Down-regulation of XBP1s alleviates the senescence of renal tubular epithelial cells induced by hypoxia/reoxygenation through Sirt3/SOD2/mtROS signaling pathway / 器官移植

Objective To investigate the role and mechanism of spliced X-box binding protein 1 (XBP1s) in the senescence of primary renal tubular epithelial cells induced by hypoxia/reoxygenation (H/R). Methods Primary renal tubular epithelial cells were divided into the normal control group (NC group), H/R group, empty adenovirus negative control group (Ad-shNC group), targeted silencing XBP1s adenovirus group (Ad-shXBP1s group), empty adenovirus+H/R treatment group (Ad-shNC+H/R group) and targeted silencing XBP1s adenovirus+H/R treatment group (Ad-shXBP1s +H/R group), respectively. The expression levels of XBP1s in the NC, H/R, Ad-shNC and Ad-shXBP1s groups were measured. The number of cells stained with β-galactosidase, the expression levels of cell aging markers including p53, p21 and γH2AX, and the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) were determined in the Ad-shNC, Ad-shNC+H/R and Ad-shXBP1s+H/R groups. Chromatin immunoprecipitation was employed to verify Sirtuin 3 (Sirt3) of XBP1s transcription regulation, and the expression levels of Sirt3 and downstream SOD2 after down-regulation of XBP1s were detected. Mitochondrial reactive oxygen species (mtROS) were detected by flow cytometry. Results Compared with the NC group, the expression level of XBP1s was up-regulated in the H/R group. Compared with the Ad-shNC group, the expression level of XBP1s was down-regulated in the Ad-shXBP1s group (both P<0.001). Compared with the Ad-shNC group, the number of cells stained with β-galactosidase was increased, the expression levels of p53, p21 and γH2AX were up-regulated, the levels of ROS, MDA and mtROS were increased, the SOD activity was decreased, the expression level of Sirt3 was down-regulated, and the ratio of Ac-SOD2/SOD2 was increased in the Ad-shNC+H/R group. Compared with the Ad-shNC+H/R group, the number of cells stained with β-galactosidase was decreased, the expression levels of p53, p21 and γH2AX were down-regulated, the levels of ROS, MDA and mtROS were decreased, the SOD activity was increased, the expression level of Sirt3 was up-regulated and the ratio of Ac-SOD2/SOD2 was decreased in the Ad-shXBP1s+H/R group (all P<0.05). Conclusions Down-regulation of XBP1s may ameliorate the senescence of primary renal tubular epithelial cells induced by H/R, which probably plays a role through the Sirt3/SOD2/mtROS signaling pathway.

Study on inhibitory effect and mechanism of hydrogen sulfide on the proliferation of cardiac fibroblasts / 中国药房

OBJECTIVE To investigate the inhibitory effect and the possible mechanism of hydrogen sulfide （H2S） on the proliferation of cardiac fibroblasts. METHODS The heart of neonatal SD rats was collected， and cardiac fibroblasts were separated with differential centrifugation. Using sodium hydrosulfide as the donor of H2S， the effects of H2S on the proliferation of cardiac fibroblasts induced by angiotensin Ⅱ （Ang Ⅱ）， hydroxyproline content and the expression of sirtuin 3 （SIRT3） protein were detected. After SIRT3 knockdown with siRNA technology， the effects of H2S on the proliferation of cardiac fibroblasts induced by Ang Ⅱ， hydroxyproline content， the expressions of collagen Ⅰ （Col Ⅰ）， collagen Ⅲ （Col Ⅲ ） and optic atrophy protein 1 （OPA1） were detected. RESULTS H2S could inhibit the proliferation of Ang Ⅱ-induced cardiac fibroblasts， reduce the content of hydroxyproline and increase the expression of SIRT3 （P＜0.05）. After down-regulating the expression of SIRT3 with siRNA technology， the inhibition of H2S on the proliferation of Ang Ⅱ-induced cardiac fibroblasts and the reduction of hydroxyproline content were both inhibited， and the effect of H2S on reducing the expression of Col Ⅰ and Col Ⅲ and enhancing the expression of OPA1 was also significantly weakened. CONCLUSIONS H2S inhibits the proliferation of Ang Ⅱ -induced cardiac fibroblasts through increasing the expression of SIRT3.

Study on differential expression of Sirtuin1 in type A aortic dissection pateints at diverse ages / 中国胸心血管外科临床杂志

@#Objective    To explore the differential expression of Sirtuin1 (SIRT1) in type A aortic dissection at diverse ages. Methods    The expression of SIRT1 and monocyte chemoattractant protein-1 (MCP-1) in aortic tissue of the patients with type A aortic dissection (an aortic dissection group) and coronary heart disease (a control group) from 2019 to 2020 in the First Hospital of China Medical University was analyzed. In each group, the patients were divided into 3 subgroups according to the age (a younger subgroup, <45 years; a middle age subgroup, 45-60 years; an elderly subgroup, > Compared with the control group, SIRT1 protein expression decreased significantly in the aortic dissection group (the younger group: 0.64±0.18 vs. 1.18±0.47; the middle age group: 0.43±0.26 vs. 0.69±0.32; the elderly group: 0.31±0.24 vs. 0.45±0.29, P<0.01). The Western blotting results showed that the expression of SIRT1 protein in the aortic dissection group decreased with age (P<0.01). The MCP-1 protein expression of younger and middle age patients in the aortic dissection group was increased compared with that in the control group (the younger group: 0.65±0.27 vs. 0.38±0.22; the middle age group: 1.08±0.30 vs. 0.46±0.36, P<0.001). MCP-1 expression increased with age (P<0.01). The result of immunohistochemical staining for SIRT1 protein was similar to that of Western blotting. Conclusion    The expression of SIRT1 decreases in patients with aortic dissection disease, and declines with age. SIRT1 may play an important role in the treatment and screening of type A aortic dissection.60 years). The quantitative real-time PCR, Western blotting and immunochemical stainning were used to detect the mRNA or protein expression of SIRT1 and MCP-1. Results    A total of 60 patients were included in each group, including 79 males and 41 females. There were 20 patients in the yonger, middle age and elderly subgroups for the two groups, respectively. Compared with the control group, the expression of SIRT1 mRNA decreased in the aortic dissection group (the younger subgroup: 4.54±1.52 vs. 8.78±2.57; the middle age group: 2.70±1.50 vs. 5.74±1.07; the elderly group: 1.41±1.33 vs. 3.09±1.14, P<0.001). Meanwhile, SIRT1 mRNA in the aortic dissection group declined with age (P<0.01).

Role of SIRT1/NLRP3 signaling pathway in sevoflurane postconditioning-induced attenuation of oxygen-glucose deprivation and restoration injury in HT22 cells / 中华麻醉学杂志

Objective:To evaluate the role of silent information regulator-1 (SIRT1)/nucleotide-binding domain (NOD)-like receptor protein-3 (NLRP3) signaling pathway in sevoflurane postconditioning-induced attenuation of oxygen-glucose deprivation and restoration (OGD/R) injury in mouse hippocampal neuronal cell line (HT22) cells.Methods:The HT22 cells were seeded in a culture plate (96-well plate, 100 μl/well; 6-well plate, 2 ml/well) at the density of 5×10 4 cells/ml or in a culture dish (6 cm in diameter) and then divided into 4 groups ( n=24 each) using a random number table method: control group (Control group), OGD/R group, sevoflurane postconditioning group (SPC group), and SIRT1 small interfering RNA group (si-SIRT 1 group). In Control group, cells were cultured at 37 ℃ in normal culture atmosphere. In OGD/R group, the culture medium was replaced with glucose-free serum-free culture medium, and cells were exposed to 95% N 2+ 5% CO 2 for 4 h in an incubator at 37 ℃, and then the glucose-free serum-free culture medium was replaced with the primary culture medium, and cells were cultured for 24 h at 37 ℃ in normal culture atmosphere. In SPC group, the glucose-free serum-free culture medium was replaced with the primary cell culture medium after 4-h oxygen and glucose deprivation, the cells were put into the hypoxia incubator chamber which was filled with 2% sevoflurane immediately after start of reoxygenation, then the chamber was placed in an incubator and the cells were cultured for 1 h at 37 ℃ in normal culture atmosphere, and finally the cells were removed from the chamber and cultured for 23 h at 37 ℃ in normal culture atmosphere. In si-SIRT1 group, SIRT1 small interfering RNA 150 pmol was added at 24 h before surgery, cells were then incubated, and the other procedures were the same as those previously described in group SPC. The cell survival rate was determined using MTT assay. TUNEL assay was used to detect cell apoptosis, and the apoptosis rate was calculated. The expression of SIRT1, NLRP3, IL-1β and IL-18 mRNA was determined using polymerase chain reaction. The expression of SIRT1, NLRP3, interleukin-1beta (IL-1β) and IL-18 was detected using Western blot. Results:Compared with Control group, the cell survival rate was significantly decreased, the apoptosis rate was increased, the expression of SIRT1 protein and mRNA was down-regulated, and the expression of NLRP3, IL-1β and IL-18 protein and mRNA was up-regulated in OGD/R group ( P<0.05). Compared with OGD/R group, the cell survival rate was significantly increased, the apoptosis rate was decreased, the expression of SIRT1 protein and mRNA was up-regulated, and the expression of NLRP3, IL-1β and IL-18 protein and mRNA was down-regulated in SPC group ( P<0.05). Compared with SPC group, the cell survival rate was significantly decreased, the apoptosis rate was increased, the expression of SIRT1 protein and mRNA was down-regulated, and the expression of NLRP3, IL-1β and IL-18 protein and mRNA was up-regulated in si-SIRT1 group ( P<0.05). Conclusions:Activation of SIRT1-NLRP3 signaling pathway is involved in sevoflurane postconditioning-induced attenuation of OGD/R injury in HT22 cells.

Relationship between SIRT1 and ferroptosis during curcumin-induced reduction of acute lung injury in a mouse model of sepsis / 中华麻醉学杂志

Objective:To evaluate the relationship between silent information regulator 1 (SIRT1) and ferroptosis during curcumin-induced reduction of acute lung injury in a mouse model of sepsis.Methods:One hundred and fifty-two SPF-grade male C57BL/6J mice, aged 8 weeks, weighing 23-27 g, were divided into 4 groups ( n=38 each) using a random number table method: sham operation group (C group), sepsis group (S group), curcumin group (Cur group) and curcumin plus SIRT1 inhibitor EX527 group (CE group). Curcumin 200 mg/kg was administered by intragastric gavage every day in Cur group. Curcumin 200 mg/kg was administered by intragastric gavage every day and EX527 5 mg/kg was intraperitoneally injected in CE group. The equal volume of solvent dimethyl sulfoxide (DMSO) was given in C group and S group. Sepsis model was developed by cecal ligation and puncture (CLP) after 5 days of consecutive administration in anesthetized animals. Twenty mice in each group were randomly selected to observe the survival condition within 7 days after CLP. The bronchoalveolar lavage fluid (BALF) was collected at 24 h after developing the model to determine the concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), IL-6 and IL-18 (by enzyme-linked immunosorbent assay), and the lung tissues were obtained for microscopic examination of the pathological changes which were scored and for determination of wet-to-dry lung weight (W/D) ratio, contents of glutathione (GSH), malondialdehyde (MDA) and iron (by colorimetry), and expression of SIRT1, glutathione peroxidase 4 (GPX4) and Acyl-CoA synthetase long chain family member 4 (ACSL4) (by Western blot). Results:Compared with C group, the 7-day survival rate after CLP was significantly decreased, the concentrations of TNF-α, IL-1β, IL-6 and IL-18 in BALF, W/D ratio and lung injury score were increased, the content of GSH in lung tissues was decreased, the contents of MDA and iron were increased, the expression of SIRT1 and GPX4 was down-regulated, and the expression of ACSL4 was up-regulated in S group ( P<0.05). Compared with S group, the 7-day survival rate after CLP was significantly increased, the concentrations of TNF-α, IL-1β, IL-6 and IL-18 in BALF, W/D ratio and lung injury score were decreased, the content of GSH was increased, the contents of MDA and iron were decreased, the expression of SIRT1 and GPX4 was up-regulated, and the expression of ACSL4 was down-regulated in Cur group ( P<0.05). Compared with Cur group, the 7-day survival rate after CLP was significantly decreased, the concentrations of TNF-α, IL-1β, IL-6 and IL-18 in BALF, W/D ratio and lung injury score were increased, the content of GSH was decreased, the contents of MDA and iron were increased, the expression of SIRT1 and GPX4 was down-regulated, and the expression of ACSL4 was up-regulated in CE group ( P<0.05). Conclusions:The mechanism by which curcumin attenuates acute lung injury may be related to activation of SIRT1 and further inhibition of ferroptosis in mice.

Relationship between miR-27a and SIRT1 during myocardial ischemia-reperfusion in rats / 中华麻醉学杂志

Objective:To evaluate the relationship between microRNA-27a (miR-27a) and silent information regulator 1 (SIRT1) during myocardial ischemia-reperfusion (I/R) in rats.Methods:Fifty clean-grade healthy male Sprague-Dawley rats, aged 2-3 months, weighing 220-280 g, were divided into 5 groups ( n=10 each) by the random number table method: sham operation group (Sham group), myocardial I/R group (I/R group), AAV9-miR-27a overexpression + myocardial I/R group (AAV+ I/R group), miR-27a antagomir + myocardial I/R group (AG+ I/R group) and AAV9-miR-27a negative control+ myocardial I/R group (NC+ I/R group). The myocardial I/R injury model was prepared by ligating the anterior descending branch of the left coronary artery for 30 min followed by 120 min reperfusion. At day 14 before ischemia, AAV9-miRNA-27a adeno-associated virus 2×10 11 v. g was injected via the tail vein in AAV+ I/R group, and AAV9-miR-27a NC 2×10 11 v. g was injected via the tail vein in NC+ I/R group. miR-27a antagomir 10 mg/kg was injected via the tail vein once a day at 3 days before ischemia in AG+ I/R group. At the end of 120 min of reperfusion, serum cardiac troponin T(cTnT), creatine kinase isoenzymes (CK-MB) and lactic dehydrogenase (LDH) concentrations and contents of glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) in myocardial tissues were determined by enzyme-linked immunosorbent assay, the percentage of myocardial infarct volume by TTC staining, the expression of miR-27a in myocardial tissues by quantitative real-time polymerase chain reaction, and the expression of SIRT1 in myocardial tissues by Western blot. Results:Compared with Sham group, the percentage of myocardial infarct volume and serum concentrations of cTnT, CK-MB and LDH were significantly increased, the contents of GSH and SOD in myocardial tissues were decreased, MDA contents were increased, miR-27a expression was up-regulated, and SIRT1 expression was down-regulated in I/R group ( P<0.05). Compared with I/R group, the percentage of myocardial infarct volume and serum concentrations of cTnT, CK-MB and LDH were significantly increased, the contents of GSH and SOD in myocardial tissues were decreased, MDA contents were increased, miR-27a expression was up-regulated, and SIRT1 expression was down-regulated in AAV+ I/R, and the percentage of myocardial infarct volume and serum concentrations of cTnT, CK-MB and LDH were significantly decreased, the contents of GSH and SOD in myocardial tissues were increased, MDA contents were decreased, miR-27a expression was down-regulated, and SIRT1 expression was up-regulated in AG+ I/R group ( P<0.05), and no significant change was found in the parameters mentioned above in NC+ I/R group ( P>0.05). Compared with AAV+ I/R group, the percentage of myocardial infarct volume and serum concentrations of cTnT, CK-MB and LDH were significantly decreased, the contents of GSH and SOD in myocardial tissues were increased, MDA contents were decreased, miR-27a expression was down-regulated, and SIRT1 expression was up-regulated in AG+ I/R group ( P<0.05). Conclusions:miR-27a is involved in the pathophysiological mechanism underlying myocardial I/R injury probably through inhibition of SIRT1 expression in rats.

Effect of exosomes derived from bone mesenchymal stem cells on postoperative cognitive function and SIRT1/NF-κB signaling pathway in aged mice / 中华麻醉学杂志

Objective:To evaluate the effect of exosomes derived from bone mesenchymal stem cells (BMSCs-EXO) on the postoperative cognitive function and silent infomation regulator 1 (SIRT1)/ nuclear factor kappa B (NF-κB) signaling pathway in aged mice.Methods:BMSCs-EXO were isolated by differential centrifugation method and then identified. Twenty healthy male C57BL/6 aged mice, aged 18 months, weighing 35-40 g, were divided into 4 groups ( n=5 each) using a random number table method: sham operation group (Sham group), operation group (O group), BMSCs-EXO group and EX527 (SIRT1 inhibitor)group. The abdomen regions were shaved for sterilization without exploratory laparotomy in Sham group. Exploratory laparotomy was performed in O group. BMSCs-EXO 50 μg was injected through the tail vein at 1 h before surgery in BMSCs-EXO group. EX527 5 mg/kg was intraperitoneally injected daily at 1-3 days before surgery, and BMSCs-EXO 50 μg was injected through the tail vein at 1 h before surgery in EX527 group. Morris water maze test was used to evaluate the learning and memory ability for 5 consecutive days staring from the 1st day after surgery. Mice were sacrificed at 1 h after the end of Morris water maze test on day 5 after surgery, and the hippocampal tissues were collected for observation of the pathological changes of hippocampal CA1 region and for determination of the expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-1β mRNA (quantitative real-time polymerase chain reaction) and SIRT1 and NF-κB p65 (by Western blot). Results:Compared with Sham group, the escape latency was significantly prolonged, the times of original platform crossing were decreased, the swimming time spent in the original platform quadrant was shortened, the expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-1β mRNA was up-regulated, the SIRT1 expression was down-regulated, the NF-κB p65 expression was up-regulated ( P<0.05), and the pathological changes of hippocampal tissues in CA1 region were found in O group. Compared with O group, the escape latency was significantly shortened, the times of original platform crossing were increased, the swimming time spent in the original platform quadrant was prolonged, the expression of TNF-α, IL-6 and IL-1β mRNA was down-regulated, the expression of SIRT1 was up-regulated, the expression of NF-κB p65 was down-regulated ( P<0.05), and the pathological changes of hippocampal tissues in CA1 region were significantly attenuated in BMSCs-EXO group ( P<0.05). Compared with BMSCs-EXO group, the escape latency was significantly prolonged, the times of original platform crossing were decreased, the swimming time spent in the original platform quadrant was shortened, the expression of TNF-α, IL-6 and IL-1β mRNA was up-regulated, the SIRT1 expression was down-regulated, the NF-κB p65 expression was up-regulated ( P<0.05), and the pathological changes of hippocampal tissues in CA1 region were accentuated in EX527 group. Conclusions:BMSCs-EXO can improve the postoperative cognitive function in aged mice, and the mechanism may be associated with the activation of SIRT1/NF-κB signaling pathway.

Role of SIRT1 in mitochondrial dysfunction in mice with lipopolysaccharide-induced brain injury / 中华麻醉学杂志

Objective:To evaluate the role of silent information regulator sirtuin 1 (SIRT1) in mitochondrial dysfunction in mice with lipopolysaccharide (LPS)-induced brain injury.Methods:Eighty clean-grade male C57BL/6 mice, aged 6-8 weeks, were divided into 4 groups ( n=20 each) by the random number table method: control group (group C), LPS-induced brain injury group (LPS group), LPS-induced brain injury plus SIRT1 inhibitor EX527 group (LPS+ E group), and LPS-induced brain injury plus SIRT1 agonist SRT1720 group (LPS+ S group). Brain injury was induced by intravenous injection of LPS 10 mg/kg. EX527 10 mg/kg was intraperitoneally injected at 72 h before LPS injection in group LPS+ E, and the equal volume of dimethyl sulfoxide was intraperitoneally injected instead in the other three groups. SRT1720 100 mg/kg was intraperitoneally injected at 30 min before LPS injection in group LPS+ S, and the equal volume of dimethyl sulfoxide was intraperitoneally injected instead in the other three groups. The novel object recognition test was performed at 24 h after LPS injection, then the mice were sacrificed, and hippocampal tissues were harvested for determination of the number of the normal neurons in the hippocampal CA1 area, ATP content and activities of mitochondrial respiratory chain complexes Ⅰ, Ⅱ, Ⅲ and Ⅳ (by spectrophotometry), and mitochondrial membrane potential (MMP) (by Jc-1 staining) and for microscopic examination of pathological changes (by Nissl staining) and ultrastructure of neuronal mitochondria (with a transmission electron microscope). Results:Compared with group C, the preference index in novel object recognition, normal neuron count, activities of mitochondrial respiratory chain complexes Ⅰ, Ⅱ, Ⅲ and Ⅳ, MMP and ATP content were significantly decreased ( P<0.05), damage to hippocampal neurons was found, mitochondrial swelling was observed and cristae structure ruptured in LPS, LPS+ S and LPS+ E groups. Compared with group LPS, the preference index in novel object recognition, activities of mitochondrial respiratory chain complexes, MMP and ATP content were significantly decreased ( P<0.05), neuronal damage was aggravated, the mitochondrial swelling and fracture of crista structure were accentuated in group LPS+ E; the preference index in novel object recognition, activities of mitochondrial respiratory chain complexes, MMP and ATP content were significantly increased ( P<0.05), neuronal damage was alleviated, and the mitochondrial swelling and fracture of crista structure were ameliorated in group LPS+ S. Conclusions:Activation of SIRT1 can improve mitochondrial dysfunction and alleviate LPS-induced brain injury in mice.

Role of SIRT1/NF-κB signaling pathway in mild hypothermia-induced promotion of microglial polarization during oxygen-glucose deprivation and restoration / 中华麻醉学杂志

Objective:To evaluate the role of Sirtuin 1/nuclear factor κB (SIRT1/NF-κB) signaling pathway in mild hypothermia-induced promotion of microglial polarization during oxygen-glucose deprivation and restoration (OGD/R).Methods:The well-grown BV2 microglia were divided into 4 groups ( n=36 each) using the random number table method: control group (group C), OGD/R group (group O), mild hypothermia group (group M), and mild hypothermia+ SIRT1 specific inhibitor EX527 group (group ME). Cells in group C were commonly cultured without any treatment. Cells in group O were subjected to 3 h of OGD followed by 21 h of restoration of O 2-glucose supply at 37 ℃. Cells in group M were subjected to 3 h of OGD followed by 21 h of restoration of O 2-glucose supply at 33 ℃. Cells in group ME were co-cultured with inhibitor EX527 (final concentration 5 nmol/L) for 12 h in the medium before OGD/R, and the other procedures were conducted as previously described in group M. The cell survival rate was detected by CCK-8 assay. The levels of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and interleukin-10 (IL-10) in supernatant were detected by enzyme-linked immunosorbent assay. The expression of CD206, CD32, inducible nitric oxide synthase (iNOS) and arginine synthase 1 (Arg-1) mRNA was detected by quantitative real-time polymerase chain reaction. The expression of CD206 and CD32 was detected by immunofluorescent staining. The expression of iNOS, Arg-1, SIRT1, NF-κB p65 (p65) and acetylated NF-κB (Ac-p65) was detected by Western blot. Results:Compared with group C, the cell survival rate was significantly decreased, the concentrations of TNF-α, IL-6 and IL-10 in the supernatant were increased, the expression of CD206, Arg-1, CD32 and iNOS was up-regulated, the expression of SIRT1 was down-regulated, and the Ac-p65/p65 ratio was increased in group O ( P<0.05). Compared with group O, the cell survival rate was significantly increased, the concentrations of TNF-α and IL-6 in the supernatant were decreased, the concentration of IL-10 was increased, the expression of CD206, Arg-1 and SIRT1 was up-regulated, the expression of CD32 and iNOS was down-regulated, and the Ac-p65/p65 ratio was decreased in group M ( P<0.05). Compared with group M, the cell survival rate was significantly decreased, the concentrations of TNF-α and IL-6 in the supernatant were increased, the concentration of IL-10 was decreased, the expression of CD206, Arg-1 and SIRT1 was down-regulated, the expression of CD32 and iNOS was up-regulated, and the Ac-p65/p65 ratio was increased in group ME ( P<0.05). Conclusions:SIRT1/NF-κB signaling pathway is involved in mild hypothermia-induced promotion of microglial polarization during OGD/R.

Mitochondrial protection effect of sirtuin2 inhibitor AGK2 on thioacetamide-induced L02 cells / 中国医师杂志

Objective:To explore the protective effect of AGK2, a selective inhibitor of sirtuin 2 (SIRT2), on the mitochondria of L02 hepatocytes induced by thioacetamide (TAA) and its related mechanism.Methods:Human-derived hepatocyte line L02 cells were cultured in vitro. Different concentrations of SIRT2 inhibitor AGK2 were used as intervention drugs. Cell counting kit-8 (CCK8) was used to detect the effects of different concentrations of AGK2 on the activity of L02 cells, and the appropriate concentration was selected as the AGK2 intervention group. The normal group was not given any drug intervention. The model group was given 90 mmol/L TAA for modeling. Low, medium and high dose AGK2 groups were added with 1, 2 and 4 μmol/L AGK2, respectively 2 h before modeling. CCK8 was used to detect cell activity in each group. Morphological changes of cells were observed under inverted light microscope. The relative protein expression levels of isocitrate dehydrogenase (IDH1), malate dehydrogenase (MDH1), SIRT2 and fission protein 1 homologue (FIS1) were detected by Western blot. The expression of SIRT2 in cells of each group was observed by confocal laser scanning microscope. The mitochondrial membrane potential of cells in each group was observed under a fluorescence microscope. Results:When AGK2 concentration was 1, 2 and 4 μmol/L, the survival rate of cells were 98.05%, 95.76% and 91.65%, respectively, with no statistical significance compared with normal group (all P>0.05). When AGK2 concentration was 8, 16, 32, 64, 128 μmol/L, the cell survival rate was significantly decreased compared with normal group (all P<0.05). Compared with the model group, the L02 cells in low, medium and high AGK2 groups had better activity and adherence, and the floating cells were significantly reduced. The higher the concentration of AGK2, the better the cell activity and adherence, and the less floating cells. Compared with the model group, the red fluorescence of L02 cells in AGK2 group was enhanced, while the green fluorescence was weakened. The higher the AGK2 concentration was, the stronger the red fluorescence was, and the weaker the green fluorescence was. Compared with the model group, the fluorescence of SIRT2 in L02 cells of low, medium and high AGK2 groups was weakened, and the higher the concentration of AGK2, the weaker the fluorescence of SIRT2. The protein expressions of IDH1 and MDH1 in L02 cells of low, medium and high AGK2 groups were significantly higher than those of model group (all P<0.05), and were positively correlated with the concentration of AGK2 ( r=0.818, P<0.05; r=0.960, P<0.05); the protein expressions of SIRT2 and FIS1 were significantly lower than those of the model group (all P<0.05), and were negatively correlated with the concentration of AGK2 ( r=-0.992, P<0.05; r=-0.998, P<0.05). Conclusions:AGK2 can reduce the mitochondrial membrane potential stimulated by TAA in L02 cells, increase the protein expression of IDH1 and MDH1, and inhibit the protein expression of SIRT2 and FIS1 in L02 cells in a dose-dependent manner.

Role of SIRT1 in regulating endoplasmic reticulum stress in early brain injury after subarachnoid hemorrhage / 国际生物医学工程杂志

Objective:To investigate the effect of Sirtuin 1 (SIRT1) on subarachnoid hemorrhage (SAH) and its possible mechanism.Methods:A mouse model of SAH was constructed by internal carotid artery puncture. The protein and mRNA expression levels of SIRT1 at 0, 3, 6, 12, 24, 48, and 72 h were detected by Western Blot and qRT-PCR. A Western Blot assay was used to examine SIRT1 and the expression levels of endoplasmic reticulum stress-related markers GRP78, p-PERK/PERK, p-eIF2α/eIF2α, and CHOP after administration of a SIRT1 inhibitor or SIRT1 si-RNA. At 24 h after SAH, subarachnoid hemorrhage volume, neurological function score, brain water content, and blood-brain barrier integrity were measured.Results:The highest expression of SIRT1 protein and mRNA was observed at 24 h compared with other time points, and the differences were statistically significant (all P < 0.001). Inhibition of SIRT1 expression leads to increased expression of endoplasmic reticulum stress-related proteins GRP78, p-PERK/PERK, p-eIF2α/eIF2α, and CHOP, exacerbating hemorrhage and brain water content, disrupting blood-brain barrier integrity, and significantly reducing neurological function scores. Conclusions:Inhibition of SIRT1 expression significantly increased the endoplasmic reticulum response to excitation and exacerbated early brain injury after SAH.

Pre-treatment of the beta3-adrenergic receptor agonist BRL37344 reduces in vivo myocardial ischemia/reperfusion injury by improving AMPK and SIRT1 activity and by suppressing mTOR and p70S6K signaling pathways

Abstract This study aimed to investigate the role and signaling pathways of β3-AR in myocardial ischemia/reperfusion (I/R) injury, which is one of the leading causes of death worldwide. 47 male rats were randomly divided into two main groups to evaluate infarct size and molecular parameters. Rats in both groups were randomly divided into 4 groups. Control (sham), I/R (30 min ischemia/120 min reperfusion), BRL37344 (BRL) (A) (5 µg/kg single-dose pre-treatment (preT) before I/R) and BRL (B) (5 µg/kg/day preT for 10 days before I/R). Infarct size was determined with triphenyltetrazolium chloride staining and analyzed with ImageJ program. The levels of AMPK, SIRT1, mTOR, and p70SK6 responsible for cellular energy and autophagy were evaluated by western blot. Infarct size increased in the I/R group (44.84 ± 1.47%) and reduced in the single-dose and 10-day BRL-treated groups (32.22 ± 1.57%, 29.65 ± 0.55%; respectively). AMPK and SIRT1 levels were decreased by I/R but improved in the treatment groups. While mTOR and p70S6K levels increased in the I/R group, they decreased with BRL preT. BRL preT protects the heart against I/R injury. These beneficial effects are mediated in part by activation of AMPK and SIRT1, inhibition of mTOR and p70S6K, and consequently protected autophagy.

Expression of sirtuin 2 and 7 in placenta accreta spectrum

SUMMARY OBJECTIVE: This study aimed to investigate the expression levels of sirtuin 2 and sirtuin 7 in the placenta accreta spectrum to reveal their role in its pathogenesis. METHODS: A total of 30 placenta accreta spectrum, 20 placenta previa, and 30 controls were experienced. The sirtuin 2 and sirtuin 7 expression levels in the placentas of these groups were determined by Western blot. sirtuin 2 and sirtuin 7 serum levels in the maternal and fetal cord blood were examined by enzyme-linked immunosorbent assay. RESULTS: It was found that sirtuin 7 in placenta accreta spectrum was significantly lower in the placenta compared to the control and placenta previa groups (p<0.05). However, a significant difference was not observed between the sirtuin 2 and sirtuin 7 levels in the maternal and fetal cord serum samples of those three groups (p>0.05). CONCLUSION: Sirtuin 7 may play an important role in the formation of placenta accreta spectrum. The effect of decreased expression of sirtuin 7 might be tissue-dependent in the placenta accreta spectrum and needs to be investigated further.

The Protective Effect of Kaempferol Against Ischemia/Reperfusion Injury Through Activating SIRT3 to Inhibit Oxidative Stress

Abstract Introduction: The objective of this study is to investigate the protective effect of kaempferol against ischemia/reperfusion (IR) injury and the underlying molecular mechanisms. Methods: H9C2 cells were pretreated with kaempferol for 24 hours and further insulted with IR injury. Cell vitality, reactive oxygen species (ROS) level, glutathione (GSH) level, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and sirtuin-3 (SIRT3), B-cell lymphoma 2 (Bcl2), and Bcl2-associated X protein (Bax) expressions were evaluated. Moreover, short interfering ribonucleic acid targeting SIRT3 was used to investigate the role of SIRT3 against IR mediated by kaempferol in vitro. IR mice models were also established to confirm the protective effects of kaempferol on IR in vivo. Results: After IR injury, H9C2 cells vitality was reduced, ROS levels, NADPH oxidase activity, and Bax expressions were increased, and GSH levels and Bcl2 expressions were decreased. After kaempferol pretreatment, the vitality of H9C2 cells was increased. The levels of ROS, NADPH oxidase activity, and Bax expression were decreased. In addition, levels of GSH and Bcl2 expression were enhanced. Furthermore, silencing SIRT3 attenuated the protective effect mediated by kaempferol, with increased ROS levels, NADPH oxidase activity, and Bax expression, along with reduced GSH level and Bcl2 expression. In vivo IR model showed that kaempferol could preserve IR-damaged cardiac function. Conclusion: Kaempferol has the capability of attenuating H9C2 cells IR injury through activating SIRT3 to inhibit oxidative stress.

Triagem biológica de inibidores de sirtuína 2 (TcSir2rp1) candidatos a antichagásicos / Biological screening of sirtuin 2 inhibitors (TcSir2rp1) antichagasic candidates

A doença de Chagas é causada pelo Trypanosoma cruzi, e atualmente, acomete entre 6 a 7 milhões de pessoas em todo o mundo. A quimioterapia disponível para seu o tratamento se baseia apenas em dois fármacos, nifurtimox e benznidazol, com mais de 50 anos de descoberto. Estes fármacos apresentam eficácia limitada, pois são pouco efetivos na fase crônica e apresentam alta toxicidade, resultando em efeitos adversos graves. Esse panorama mostra a necessidade de novas abordagens terapêuticas contra essa doença. Nesse sentido, a inibição de vias bioquímicas essencias para o parasita se mostram como uma boa sugestão para identificação de compostos promissores candidatos a novos agentes quimioterápicos. A sirtuína 2 (Sir2) são enzimas reguladoras que participam de mecanismos epigenéticos em tripanossomatídeos, e no T. cruzi possuem um papel fundamental em todos os seus estágios evolutivos, devido a este fato, se apresentam como um alvo promissor na busca por novos fármacos contra a doença de Chagas. Neste sentido propomos a busca de inibidores da Sir2 proteína 1 do T. cruzi (TcSir2rp1) que é geneticamente validada como alvo farmacológico, por meio da estratégia de triagem biológica. Realizou-se a expressão da enzima recombinante por biologia molecular em um sistema de transformação utilizando cepa de Escherichia coli Artic Express (DE3). Foi feita a purificação e a confirmação da obtenção da proteína recombinante se deu por gel SDS-PAGE. Após a obtenção da enzima os parâmetros cinéticos foram determinados por experimentos de fluorimetria. A triagem foi realizada para um conjunto de 82 compostos, previamente sintetizados pelo nosso grupo de pesquisa, como inibidores da TcSir2p1 em dose única de 100 µM. Os ensaios foram realizados em triplicata e em experimentos independentes. Dentre os 82 compostos testados, 20 apresentaram inibições maior que 50% contra a enzima TcSir2rp1, na dose de 100 µM. Dentre estes, se destacaram 3 compostos derivados de chalconas, para os quais foi determinada a potência. O composto 1 foi o que mais potente, apresentando valor de IC50 de 11,65 µM, já os compostos 3 e 5 foram menos potentes (IC50= 38,50 µM e 19,85 µM, respectivamente). Diante dos resultados obtidos, pode-se concluir que a estratégia de triagem biológica é promissora na identificação de inibidores da TcSir2p1 candidatos a agentes anti- T. cruzi

Chagas disease is caused by Trypanosoma cruzi, and currently affects 6 to 7 million people worldwide. The chemotherapy available for its treatment is based on only two drugs, nifurtimox and benznidazole, with more than 50 years of discovery. These drugs have limited efficacy, as they are ineffective in the chronic phase and have high toxicity, resulting in serious adverse effects. This panorama shows the need for new therapeutic approaches against this disease. In this sense, the inhibition of essential biochemical pathways for the parasite proves to be a good suggestion for the identification of promising compounds candidates for new chemotherapeutic agents. Sirtuin 2 (Sir2) are regulatory enzymes that participate in epigenetic mechanisms in trypanosomatids, and in T. cruzi they have a fundamental role in all their evolutionary stages, due to this fact, they present themselves as a promising target in the search for new drugs against Chagas disease. In this sense, we propose the search for inhibitors of Sir2 protein 1 of T. cruzi (TcSir2rp1) which is genetically validated as a pharmacological target, through the biological screening strategy. The expression of the recombinant enzyme was performed by molecular biology in a transformation system using strain of Escherichia coli Artic Express (DE3). Purification was performed and confirmation of obtaining the recombinant protein was performed by SDS-PAGE gel. After obtaining the enzyme, the kinetic parameters were determined by fluorimetry experiments. Screening was performed for a set of 82 compounds, previously synthesized by our research group, as TcSir2p1 inhibitors in a single dose of 100 µM. Assays were performed in triplicate and in independent experiments. Among the 82 compounds tested, 20 showed inhibitions greater than 50% against the enzyme TcSir2rp1, at a dose of 100 µM. Among these, 3 compounds derived from chalcones stood out, for which the potency was determined. Compound 1 was the most potent, with an IC50 value of 11.65 µM, while compounds 3 and 5 were less potent (IC50= 38.50 µM and 19.88 µM, respectively). In view of the results obtained, it can be concluded that the biological screening strategy is promising in the identification of TcSir2p1 inhibitors candidates for anti-T. cruzi agents

Planejamento, síntese e avaliação biológica de candidatos a fármacos: busca de inibidores epigenéticos da Sirtuína 2 Sir2 / Design, synthesis and biological evaluation of drug candidates: search for Sirtuin 2 (Sir 2) epigenetic inhibitors

As doenças negligenciadas são causadas por agentes infecciosos e parasitários, como vírus, bactérias, protozoários e helmintos. Essas doenças são prevalentes em populações de baixa renda que vivem em países em desenvolvimento e são responsáveis por incapacitar e levar milhares de pessoas à morte. Este nome se dá pois, apesar de sua grande relevância médica, recebem pouca atenção dos governos e indústrias farmacêuticas. Dentre essas doenças podemos destacar a Doença de Chagas, doença infecciosa causada pelo parasita hemoflagelado Trypanosoma cruzi. Endêmica em 21 países, com 6 a 7 milhões de pessoas infectadas resultando em 7500 mortes por ano. A quimioterapia disponível contra essa parasitose é baseada em apenas dois medicamentos, o benznidazol e o nifurtimox, ativos principalmente na fase aguda da doença e com efeitos adversos graves que comprometem a adesão ao tratamento e, além disso, apesar dos enormes esforços na pesquisa de novos agentes antichagásicos em nível nacional e internacional, na maioria realizada academicamente, ainda não foram encontradas alternativas terapêuticas para a doença, persistindo, assim, a necessidade de descoberta e desenvolvimento de novos fármacos. O início de um planejamento de um novo fármaco se dá pela definição de um alvo bioquímico a ser utilizado na busca de moléculas que possam exercer a função de inibidores ou moduladores, conforme a atividade biológica desejada. Neste sentido, as sirtuínas 2 (Sir2) são enzimas que se mostraram essenciais para o crescimento in vitro do T. cruzi em suas formas amastigota e epimastigota. No caso de tripanossomatídeos, em geral, a superexpressão de Sir2 está relacionada à sobrevivência de formas amastigotas. Assim, essas evidências indicam que a Sir2 de tripanosomatídeos tem grande potencial como alvo biológico na busca e desenvolvimento de novos fármacos antichagásicos. O objetivo principal deste projeto foi identificar moléculas que apresentaram atividade inibitória para a sirtuína 2 de T. cruzi por meio da utilização da estratégia de Planejamento de Fármacos Baseada no Ligante - Ligand Based Drug Design (LBDD) e o desenvolvimento de análogos dos inibidores da Sir2. A modificação molecular está entre algumas das técnicas tradicionais usadas no desenvolvimento racional de um fármaco, e é usada principalmente no desenvolvimento de análogos, e busca melhorar as propriedades farmacocinéticas e/ou farmacodinâmicas de um protótipo, obter propriedades de interação semelhantes ao alvo e, em alguns casos, revelar uma atividade biológica. Com este intuito, análogos do sirtinol e da salermida foram sintetizados e uma nova rota sintética utilizando o microrreator em fluxo contínuo foi desenvolvida e apresentou rendimento superior quando comparado à síntese em bancada. A partir desta metodologia foram obtidos 20 compostos. Os ensaios in vitro contra formas amastigotas do T. cruzi indicaram que 8 compostos inibiram a atividade parasitária em mais de 50%, na dose de 10 µM, sendo que alguns destes apresentaram maior inibição parasitária quando comparados ao benznidazol, o fármaco de referência e único disponível no Brasil. Com estes resultados preliminares, novos ensaios estão sendo realizados para identificar potência e mecanismo de ação destes candidatos a agentes tripanomicidas

Neglected diseases are caused by infectious and parasitic agents such as viruses, bacteria, protozoa and helminths. These diseases are prevalent in low-income populations living in developing countries and are responsible for disabling and killing thousands of people. They get this name because, despite their great medical relevance, they end up receiving little attention from governments and pharmaceutical industries. Among these diseases, we can highlight Chagas disease, an infectious endemic disease caused by the hemoflagellate parasite Trypanosoma cruzi. This disease is endemic in 21 countries, with 6 to 7 million people infected resulting in 7,500 deaths per year. Chemotherapy is based on just two drugs, benznidazole and nifurtimox, which are mainly active in the acute phase of the disease. These drugs have adverse effects that compromise adherence, even more, considering that they are not effective from the point of view of the chronic phase of the disease. Despite the enormous efforts in researching new anti-chagasic agents at the national and international level, and mostly carried out academically, therapeutic alternatives for the disease have not yet been found, thus, the need for the discovery and development of new drugs persists. Sirtuins 2 (Sir2) are enzymes that have been shown to be essential for the in vitro growth of T. cruzi in its amastigote and epimastigote forms. In the case of trypanosomatids in general, Sir2 overexpression is related to the survival of amastigote forms. Sir2 inhibitors, such as sirtinol, have shown efficacy in leishmanicides. Thus, these evidences indicate that Sir2 from trypanosomatids can be considered as a biological target in the search and development of new anti-chagasic drugs. The beginning of a new drug planning study is the definition of a biochemical target to be used in the search for molecules that can play the role of inhibitors or modulators, according to the desired biological activity. The main objective of this project was to identify molecules that presented inhibitory activity to sirtuin 2 of T. cruzi using the Ligand Based Drug Design (LBDD) strategy of planning and the development of analogues of Sir2 inhibitors. Molecular modification is a traditional technique used in the rational development of a drug, as well as the use of natural products, combinatorial chemistry, high-throughput screening (HTS), among others. Mainly used in the development of analogues, molecular modification is applied for different purposes, among them, it seeks to improve the pharmacokinetic and/or pharmacodynamic properties of a prototype, obtain target-like interaction properties and, in some cases, reveal an activity biological. For this purpose, analogues of sirtinol and salermide were synthesized and a new synthetic route using the microreactor in continuous flow was developed and presented superior yield when compared to benchtop synthesis. From this methodology, 20 compounds were obtained. in vitro assays against amastigote forms of T. cruzi indicated that 8 compounds inhibited parasitic activity by more than 50% at a dose of 10 µM, and some of these showed greater parasitic inhibition when compared to benznidazole, the reference drug, and only available in Brazil. With these preliminary results, new assays are being carried out to identify the potency and mechanism of action of these candidate trypanocidal agents

Nicotinamide mononucleotide attenuates ischemia-reperfusion injury induced by donor liver from cardiac death through Sirt3 / 器官移植

Objective To evaluate the effect and mechanism of nicotinamide mononucleotide (NMN) on ischemia-reperfusion injury (IRI) induced by donor liver after cardiac death in rat models. Methods Rat models of orthotopic liver transplantation were established by "magnetic ring + double cuff" method. SD rats were randomly divided into the sham operation group (Sham group), orthotopic liver transplantation group (OLT group), NMN treatment + orthotopic liver transplantation group (NMN group), NMN+sirtuin-3 (Sirt3) inhibitor (3-TYP) + orthotopic liver transplantation group (NMN+3-TYP group), respectively. Pathological changes and hepatocyte apoptosis of the rats were observed in each group. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were determined. Superoxide dismutase (SOD) and malondialdehyde (MDA) contents in liver tissues were detected. The expression levels of Sirt3, microtubule-associated protein 1 light chain 3 (LC3)Ⅱ, PTEN-induced putative kinase 1 (PINK1), Parkin and translocase of the outer mitochondrial membrane 20 (TOMM20) in liver tissues were measured. Postoperative survival of the rats in each group was analyzed. Results Compared with the Sham group, serum ALT and AST levels were higher in the OLT group. Compared with the OLT group, the levels of ALT and AST were decreased in the NMN group. Compared with the NMN group, the levels of ALT and AST were increased in the NMN +3-TYP group (all P < 0.05). The liver tissue structure of rats in the Sham group was basically normal. In the OLT group, pathological changes, such as evident congestion, vacuolar degeneration and hepatocyte necrosis, were observed in the liver tissues. Compared with the Sham group, Suzuki score and apoptosis rate were higher in the OLT group. Suzuki score and apoptosis rate in the NMN group were lower than those in the OLT group. Suzuki score and apoptosis rate in the NMN+3-TYP group were higher compared with those in the NMN group (all P < 0.05). Compared with the Sham group, the SOD content was decreased, whereas the MDA content was increased in the OLT group. Compared with the OLT group, the SOD content was increased, whereas the MDA content was decreased in the NMN group. Compared with the NMN group, the SOD content was decreased, whereas the MDA content was increased in the NMN+3-TYP group (all P < 0.05). Compared with the Sham group, the relative expression levels of Sirt3 and TOMM20 proteins were down-regulated, whereas those of PINK1, Parkin and LC3Ⅱproteins were up-regulated in the OLT group. Compared with the OLT group, the relative expression levels of Sirt3, PINK1, Parkin and LC3Ⅱproteins were up-regulated, whereas that of TOMM20 protein was down-regulated in the NMN group. Compared with the NMN group, the relative expression levels of PINK1, Parkin and LC3Ⅱproteins were down-regulated, whereas that of TOMM20 protein was up-regulated in the NMN+3-TYP group (all P < 0.05). In the Sham group, the 7 d survival rate of rats was 100%, 50% in the OLT group, 75% in the NMN group and 58% in the NMN+3-TYP group, respectively. Conclusions NMN may enhance the antioxidative capacity of the liver, induce PINK1/Parkin-mediated mitochondrial autophagy, and alleviate IRI of the liver by up-regulating Sirt3, thereby playing a protective role in the donor liver after cardiac death.

Inhibiting silence information regulator 2 and glutaminase in the amygdala can improve social behavior in autistic rats / 浙江大学学报·医学版

OBJECTIVE@#To investigate the underlying molecular mechanisms by which silence information regulator (SIRT) 2 and glutaminase (GLS) in the amygdala regulate social behaviors in autistic rats.@*METHODS@#Rat models of autism were established by maternal sodium valproic acid (VPA) exposure in wild-type rats and SIRT2-knockout ( SIRT2 -/-) rats. Glutamate (Glu) content, brain weight, and expression levels of SIRT2, GLS proteins and apoptosis-associated proteins in rat amygdala at different developmental stages were examined, and the social behaviors of VPA rats were assessed by a three-chamber test. Then, lentiviral overexpression or interference vectors of GLS were injected into the amygdala of VPA rats. Brain weight, Glu content and expression level of GLS protein were measured, and the social behaviors assessed.@*RESULTS@#Brain weight, amygdala Glu content and the levels of SIRT2, GLS protein and pro-apoptotic protein caspase-3 in the amygdala were increased in VPA rats, while the level of anti-apoptotic protein Bcl-2 was decreased (all P<0.01). Compared with the wild-type rats, SIRT2 -/- rats displayed decreased expression of SIRT2 and GLS proteins in the amygdala, reduced Glu content, and improved social dysfunction (all P<0.01). Overexpression of GLS increased brain weight and Glu content, and aggravated social dysfunction in VPA rats (all P<0.01). Knockdown of GLS decreased brain weight and Glu content, and improved social dysfunction in VPA rats (all P<0.01).@*CONCLUSIONS@#The glutamate circulatory system in the amygdala of VPA induced autistic rats is abnormal. This is associated with the upregulation of SIRT2 expression and its induced increase of GLS production; knocking out SIRT2 gene or inhibiting the expression of GLS is helpful in maintaining the balanced glutamate cycle and in improving the social behavior disorder of rats.

The role of down-regulation of Sirtuin 3 in skeletal muscle injury induced by iron excess / 中华内分泌代谢杂志

Objective:To explore the role of SIRT3 down-regulation in skeletal muscle injury through the changes of sirtuin 3 (SIRT3) expression in mouse skeletal muscle under iron excess in vitro or in vivo.Methods:Murine preosteoblast myoblast C2C12 cells were incubated in a medium supplemented with ferric ammonium citrate (FAC). The proliferation, apoptotic were assessed, the cell morphology was observed, and the expression of SIRT3 mRNA, protein and activity were detected. ICR mice were randomly divided into control group, FAC group and FAC+ deferrioxamine (deferoxamine, DFO) group. Normal saline was injected in the control group. FAC followed by injection of normal saline in the FAC group; and FAC followed by DFO in the FAC+ DFO group. The non-heme iron level, content of SIRT3 protein and in situ apoptosis were detected, morphology of skeletal muscle was observed.Results:Proliferation of C2C12 cells was inhibited, and the apoptotic rate were increased by FAC ( P<0.05). The mRNA, protein and activity of SIRT3 decreased by FAC ( P<0.05). The cells gradually shrank, and the length and number of myotubes were decreased by FAC. Both control and FAC+ DFO groups showed lower levels of non-heme iron in skeletal muscle compared with FAC group ( P<0.05). The levels of SIRT3 protein were decreased in FAC group compared with control group, while increased in FAC+ DFO group with FAC group ( P<0.05). The apoptotic indexes in control and FAC+ DFO groups were lower than that in FAC group. Compared with the control group, the disordered cell arrangement, fat deposition and inflammatory cell infiltration were presented in FCA group, and the change was alleviated in FAC+ DFO group. Conclusion:Iron excess can lead to the decrease of skeletal muscle mass in mice, and the mechanism may be related to the down-regulation of SIRT3 level.

Relationship between SIRT3 and mitochondrial function in mice with endotoxin-induced lung injury / 中华麻醉学杂志

Objective:To evaluate the relationship between silent information regulator 2 homologue 3 (SIRT3) and mitochondrial function in mice with endotoxin-induced lung injury.Methods:Twenty clean-grade healthy adult male wild C57BL/6 (SIRT3 + /+ ) mice, 20 SIRT3 knockout (SIRT3 -/-) mice, weighing 20-25 g, aged 6-8 weeks, were studied.SIRT3 + /+ mice and SIRT3 -/- mice were divided into 4 groups ( n=5 each) according to the random number table method: blank control group (group C, group SIRT3 -/-C), endotoxin-induced lung injury group (group L, group SIRT3 -/-L), endotoxin-induced lung injury plus resveratrol group (group L+ R, group SIRT3 -/-L+ R), and resveratrol group (group R, group SIRT3 -/-R). Resveratrol 15 mg/kg was intraperitoneally injected once a day for 7 consecutive days in L+ R, R, SIRT3 -/-L+ R and SIRT3 -/-R groups, while the equal volume of normal saline was injected in the rest groups.Lipopolysaccharid 15 mg/kg was injected via the tail vein to develop a mouse model of endotoxin-induced lung injury at 30 min after resveratrol injection on 7th day, in L+ R and SIRT3 -/-L+ R groups and at the corresponding time points in L and SIRT3 -/-L groups, while the equal volume of normal saline was injected in the other groups.Blood samples were collected from the orbital venous plexus at 12 h after injection of normal saline or lipopolysaccharid for determination of serum total oxidation state (TOS) and total antioxidant state (TAS) levels by the xylenol orange method and ABTS colorimetric method, and the oxidative stress index (OSI) was calculated.After the mice were sacrificed, the lung tissues were taken for microscopic examination of the pathological changes which were scored and for determination of the mitochondrial membrane potential (MMP) (by JC-1 method), cellular oxygen consumption rate (OCR) (by the specific fluorescent probe method), and expression of SIRT3 (by Western blot). Results:Compared with group C or group SIRT3 -/-C, the lung injury score, serum TOS concentration and OSI were significantly increased, TAS concentration, MMP and OCR were decreased, and SIRT3 expression was down-regulated in L, L+ R, SIRT3 -/-L and SIRT3 -/-L+ R groups ( P<0.05). Compared with group L, the lung injury score, serum TOS concentration and OSI were significantly decreased, TAS concentration, MMP and OCR were increased, and SIRT3 expression was up-regulated in group L+ R, and lung injury score, serum TOS concentration and OSI were significantly increased, TAS concentration, MMP and OCR were decreased, and SIRT3 expression was down-regulated in group SIRT3 -/-L ( P<0.05). Compared with group L+ R, the lung injury score, serum TOS concentration and OSI were significantly increased, the TAS concentration, MMP and OCR were decreased, and the expression of SIRT3 was down-regulated in group SIRT3 -/- L+ R ( P<0.05). There was no significant difference in the indicators mentioned above between group SIRT3 -/-L+ R and group SIRT3 -/-L ( P>0.05). Conclusions:Down-regulation of SIRT3 expression can lead to impaired mitochondrial function, which is involved in the pathophysiological mechanism of endotoxin-induced lung injury.