Effect of knockdown of PRDX6 on adaptive expression of bile acid transporter in HepG2 cells induced by rifampicin / 安徽医科大学学报

Objective @#To investigate the role of knockdown of peroxiredoxin-6 ( PRDX6) in injury and adaptive expression of bile acid transporter in human hepatoellular carcinomas ( HepG2 ) cells induced by rifampicin (RFP) . @*Methods @#Cells in logarithmic growth phase were uniformly inoculated in six-well plates , and HepG2 cells were transiently transfected with specific PRDX6-siRNA and control-siRNA to construct the knockdown group and control group . After 24 h of induction with 100 μmol/L RFP , Western blot and qRT-PCR were performed to detect the protein and gene expression levels of PRDX6 , multidrug resistance protein 1 (MDR1) , multidrug resist- ance-associated proteins 2 , 3 and 4 (MRP2 , MRP3 and MRP4) , and Na + /taurine taurocholate cotransporter pro- tein (NTCP) . Annexin V-FITC/PI double staining assay was used to detect the apoptosis rate of cells in each group ; CCK-8 assay was used to detect the changes of cell proliferation in each group; The relative contents of ala- nine aminotransferase ( ALT) , aspartate aminotransferase ( AST) , total bilirubin ( TBIL) , indirect bilirubin (IBIL) and total bile acid (TBA) in the supernatant of cell culture medium of each group were detected by kits .@*Results @#RFP increased the protein and gene expression levels of MRP2 , MRP3 , MRP4 , MDR1 , NTCP and PRDX6 in HepG2 cells (P < 0. 05) , while the protein and gene expression levels of MRP2 , MRP3 , MRP4 , MDR1 and NTCP decreased to different degrees after PRDX6 knockdown (P < 0. 05) . In addition , PRDX6 knockdown re- sulted in increased apoptosis rate of HepG2 cells (P < 0. 05) , decreased cell proliferation ability (P < 0. 05) , and increased levels of cell injury markers (ALT , AST , TBIL , DBIL , TBA) in cell culture supernatants (P < 0. 05) . @*Conclusion @#RFP increased the protein and gene expression of bile acid transporter and PRDX6 to increase in HepG2 cells . However , following knockdown of PRDX6 and treatment with RFP , the protein and gene expression levels of the bile acid transporter decreased and cell injury was aggravated , suggesting that PRDX6 played a protec- tive role in RFP-induced adaptive response in HepG2 cells .

Curcumin may inhibit chondrocytes ferroptosis by upregulating the Prdx6 expression level / 安徽医科大学学报

Objective To investigate the role and possible mechanism of curcumin(Cur)regulating Peroxiredoxin-6(Prdx6)expression in inhibiting Erastin-induced ferroptosis in C28/I2 chondrocytes.Methods Safranin O/Fast Green and hematoxylin-eosin(HE)staining were performed to observe the pathological changes in the knee joint of rats with osteoarthritis(OA).The expression levels of Prdx6 and GPX4 proteins in cartilage tissues with OA were detected by immunohistochemistry and Western blot.C28/I2 chondrocytes were treated with different concentrations of Cur,cell viability was detected by thiazolyl blue tetrazolium bromide(MTT)assay and cytotoxicity was measured by lactic dehydrogenase(LDH)assay.The production of lipid reactive oxygen species(ROS)in chondrocytes was detected by flow cytometry,and the total glutathione(GSH)assay kit was used to detect the GSH level in chondro-cytes.Western blot was performed to detect the expression level of Prdx6 and ferroptosis-related proteins in chon-drocytes.The interaction between the Cur molecule and Prdx6 was analyzed through the molecular docking tech-nique.Results During the OA progression,OA rats and OA patients showed pathological changes such as damage to the cartilage and a decrease in the number of chondrocytes.The expression levels of Prdx6 and GPX4 were re-duced in the cartilage tissues of OA patients compared with healthy people.Further study revealed that the treat-ment of Erastin-induced ferroptosis in C28/I2 chondrocytes in a mouse model with 20 μmol/L of Cur could improve cell viability,decrease cytotoxicity,inhibit lipid ROS production,and increase the level of intracellular GSH.Western blot results showed decreased expression of Prdx6,SLC7A11,FTH,and GPX4 and increased expression of ACSL4.In addition,Cur molecules interacted with Prdx6 protein by van der Waals forces and π bond.Conclu-sion Cur may inhibit Erastin-induced ferroptosis in C28/I2 chondrocytes by upregulating the Prdx6 expression lev-el.

Biochemical relationship between leiomyosarcoma and peroxiredoxin-6 expression level: Clinical implications

Uterine leiomyosarcomas are tumors with a heterogeneous genetic profiles that respond very poorly to cytotoxic chemotherapy with aggressive progression. We aimed to show the status of peroxiredoxin 6 as a biomarker in leiomyosarcoma progression.Study included 12 patients diagnosed with "leiomyosarcoma" and 13 patients diagnosed with "myoma" (as control) after histopathological examinations of clinical samples. Peroxiredoxin-6 gene expression and protein levels were evaluated on the tumor preparations (blocks) utilizing ELISA and PCR methods.Peroxiredoxin-6 protein was mainly localized in the cytoplasm of leiomyosarcoma cells, and the expression of peroxiredoxin-6 was significantly increased in cancerous tissues compared to normal myoma tissues (3.33±1.7 vs. 2.03±1.07fold change; P= 0.031). Peroxiredoxin-6 tissue protein levels were also significantly higher in leiomyosarcoma cases (100.54±66.86 vs. 183.72±64.54 pg/µg protein; P= 0.005). Our findings demonstrate that peroxiredoxin-6 plays a vital role in the emergence and development of leiomyosarcoma and that peroxiredoxin-6 level assessments can be used as a biomarker in guiding better prognosis andtreatment plans while managing leiomyosarcoma.

Phospholipid remodeling and Parkinson's disease / 药学学报

The remodeling of phospholipid includes two processes: deacylation and reacylation. It realizes the conversion of nascent phospholipids to mature phospholipids by changing the length and types of fatty acids at specific sites of phospholipids, which is a key step in phospholipid metabolism. Phospholipids are not only the basic components of biological membranes, but also participate in the transduction of many molecular signals in cells. Therefore, phospholipid remodeling disorders can affect the structure and function of cell membranes, as well as the activity of membrane proteins, causing a series of intricate signaling cascades, and finally lead to many pathological changes including neurodegeneration. This paper reviews the basic process of phospholipid remodeling and the involvement of its key enzymes, calcium independent group VIA phospholipase A2 (iPLA2β), peroxiredoxin 6 (PRDX6), calcium independent group VIB phospholipase A2 (iPLA2γ) as well as acyl-CoA lysocardiolipin acyltransferase 1 (ALCAT1) in the pathology of Parkinson's disease. The mutations in the gene encoding iPLA2β, PLA2G6, have been widely reported to be directly related to hereditary Parkinson disease-14 (PARK14). Here we focus on the molecular mechanism of iPLA2β in the development of Parkinson's disease, mainly involving phospholipid fatty acid metabolism disorders, mitochondrial physiology abnormalities and α-synuclein aggregate formation and other aspects, which will help to understand the role of phospholipid remodeling in Parkinson's disease, and provide new clues for the development of new Parkinson's disease diagnosis and treatment strategies.

Mechanism of Schisandrae Chinensis Fructus Lignans in Alleviating Learning and Memory Ability in D-galactose Aging Mice / 中国实验方剂学杂志

Objective:To study the effect of Schisandrae Chinensis Fructus lignans (SCL) on learning and memory ability of D-galactose（D-gal）-induced aging model mice. Method:ICR mice were randomly divided into 4 groups: normal group (distilled water, subcutaneous injection with normal saline), model group (distilled water, subcutaneous injection with 200 mg·kg-1D-gal), piracetam group (oral administration with 200 mg·kg-1 piracetam, subcutaneous injection with 200 mg·kg-1D-gal), low-dose SCL group (oral administration with 50 mg·kg-1·d-1 SCL, subcutaneous injection with 200 mg·kg-1·d-1 D-gal), medium-dose SCL group (oral administration with 100 mg·kg-1·d-1 SCL, subcutaneous injection with 200 mg·kg-1·d-1D-gal), high-dose SCL group (oral administration with 200 mg·kg-1·d-1 SCL, subcutaneous injection with 200 mg·kg-1·d-1 D-gal). The drugs were administered continuously for 10 weeks. Dark test and Morris water maze test were performed to observe the effect of SCL on the learning and memory ability of D-gal-induced aging mice. The activities of superoxide dismutase (SOD) and malondialdehyde (MDA) in mouse brain tissue were detected by chemical colorimetry. The expressions of peroxiredoxin-6（Prdx6） and glutathione peroxidase 1（GSH-Px1） mRNA in mouse brain tissue were detected by polymerase chain reaction (PCR). The expressions of Prdx6 and GSH-Px1 protein in mouse tissues were detected by Western blot. Result:In behavioral experiments, compared with normal group, the number of dark avoidance errors in model group significantly increased (P<0.05), the latency was significantly reduced (P<0.01), and the number of mouse passes and the target quadrant residence time were significantly reduced (P<0.01), which can be used as an indicator of successful modeling. Compared with the model group, the number of errors in the piracetam group, and medium and high-dose SCL groups was significantly reduced (P<0.05，P<0.01), and the latency was significantly prolonged (P<0.05，P<0.01). At the same time, the number of water maze passes and the target quadrant retention time in the high-dose SCL group increased significantly (P<0.01). The results of biochemical indicators showed that compared with normal group, the SOD activity in brain tissue of model group mice was significantly reduced (P<0.01), while the MDA content was increased (P<0.05). Compared with the model group, SOD activity in the brain tissues of piracetam group, and low, medium and high-dose piracetam groups was significantly increased (P<0.05), whereas the level of MDA was reduced (P<0.05). The expressions of Prdx6 and GSH-Px1 were significantly increased (P<0.05，P<0.01), indicating that the SCL administration group was dose-dependent. Conclusion:SCL can improve the learning and memory ability of D-gal-induced aging mice, which may be related to the anti-oxidation ability of SCL and the up-regulation of Prdx6 and GSH-Px1 expressions in mouse brain tissue.

Oxidative Stress Modulates the Expression Pattern of Peroxiredoxin-6 in Peripheral Blood Mononuclear Cells of Asthmatic Patients and Bronchial Epithelial Cells

PURPOSE: Reduction-oxidation reaction homeostasis is vital for regulating inflammatory conditions and its dysregulation may affect the pathogenesis of chronic airway inflammatory diseases such as asthma. Peroxiredoxin-6, an important intracellular anti-oxidant molecule, is reported to be highly expressed in the airways and lungs. The aim of this study was to analyze the expression pattern of peroxiredoxin-6 in the peripheral blood mononuclear cells (PBMCs) of asthmatic patients and in bronchial epithelial cells (BECs).METHODS: The expression levels and modifications of peroxiredoxin-6 were evaluated in PBMCs from 22 asthmatic patients. Phosphorylated and acetylated peroxiredoxin-6 in hydrogen peroxide-treated human BECs was detected using immunoprecipitation analysis. The expression level of peroxiredoxin-6 was also investigated in BECs treated with hydrogen peroxide. Cycloheximide and proteasome inhibitors were used to determine whether peroxiredoxin-6 is degraded by proteasomes.RESULTS: Peroxiredoxin-6 expression was significantly reduced in the PBMCs of asthmatic patients compared to control subjects. Distinct modification patterns for peroxiredoxin-6 were observed in the PBMCs of asthmatic patients using 2-dimensional-electrophoresis. The levels of phosphorylated serine and acetylated lysine in peroxiredoxin-6 were significantly increased in the BECs following hydrogen peroxide treatment. The level of peroxiredoxin-6 expression was reduced in hydrogen peroxide-stimulated BECs, presumably due to proteasomes.CONCLUSIONS: The expression of peroxiredoxin-6, which is down-regulated in the immune cells of asthmatic patients and BECs, can be modified by oxidative stress. This phenomenon may have an effect on asthmatic airway inflammation.

Effects and mechanism of peroxiredoxin-6 on uItravioIet induced corneaI injury in rats / 中国药科大学学报

To investigate the therapeutic effect of peroxiredoxin-6(PRDX6)on ultraviolet-induced corneal injury in rats and explore the mechanism.The rat model of corneal injury was established by exposing to ultravio-let.Male wister rats were randomly divided into control groups,dexamethasone (DXM)groups and PRDX6 groups,the rats were administered four times a day and for 12 days.The corneal opacity was observed with a slit-lamp microscope.Histopathologic changes were observed with light microscopy.The content of corneal malonalde-hyde(MDA)was determined by thiobarbituric acid test and the total antioxidative capacity(TAOC)was detected by chemical colorimetric test.P38 MAPK signal pathway was detected with the method of Western blot and the gene expression of cytokines were measured by RT-PCR method.Compared with the control group,PRDX6 treat-ment significantly reduced corneal opacity,improved corneal pathology injury,decreased the MDA content and in-creased the TAOC.In the PRDX6 group the level of phosphorylated p38 protein was significantly lower than that in the control group.The gene expression of cytokine were different between control and PRDX6 groups(P <0.05).PRDX6 showed therapeutic effect in the rat model of ultraviolet-induced corneal injury.This maybe be concerned with that it could alleviated the oxidative damage,suppressed p38 MAPK phosphorylation and regulate the gene expression of cytokine.

Dynamic expression of peroxiredoxin 6 in retina of experimental diabetic rat / 中华实验眼科杂志

Background Oxidative stress plays an important role in the pathogenesis of diabetic complications.Peroxiredoxin 6(Prx6) is a doubly-functional protein.and its ability to eliminate phospholipid hydroperoxides is essential. Objective The aim of this study was to investigate the dynamic expression of Prx6 in the retina of streptozotocin(STZ)-induced diabetes and explore its correlation with the progression of diabetic retinopathy. Methods Diabetes was induced by an intraperitoneal injection of streptozotocin(STZ)in 48 clean Wistar rats.The rats were sacrificed at 1,2,and 4 months after the injection of STZ,and expressions of Prx6 protein and Prx6 mRNA in the retina was determined by immunohistochemistry and reverse transcription polymerase chain reaction.Another 12 matched normal Wistar rats were used as the control group. Results The resuh of immunohistochemistry showed that Prx6 protein was expressed in the cytoplasm of the outer nuclear layer(ONL)and inner nuclear layer(INL)in normal rats,and low expression of Prx6 protein was observed in the ganglion cell layer (GCL).In the first month,Prx6 protein was strongly expressed in the INL and the ONL of diabetic rats.However.two and three months after STZ administration,the expression of Prx6 protein was absent in the retina,showing a considerable difference among different course groups(F=22 967.63,P＜0.05).Furthermore,the expression trend of Prx6 mRNA in the retina was similar to that of the Prx6 protein with a significant difference among different course groups(F=942.84,P＜0.05). Conclusion It is conceivable that normal maintenance of Prx6 expression may be important to the prevention of diabetic retinopathy.We hypothesize that oxidative impairments in the retina that develop over time may partly contribute towards the development of retinal dysfunction,which eventually leads to retinal degeneration during the progressive phase of STZ-induced diabetes in adult rats.