A case of podocyte infolding glomerulopathy / 中华肾脏病杂志

Podocyte infolding glomerulopathy (PIG) is a pathologic type of podocyte glomerulopathy reported recently. The characteristic is that the ultrastructure related to podocytes, such as microspheres and microtubules, are folded into the glomerular basement membrane (GBM) under electron microscope. At present, there are few reports about this disease at home and abroad, and most of them are concentrated in Japan. The clinical characteristics and pathogenesis of PIG are still unclear. In this paper, we report a case of clinical manifestations of nephrotic syndrome, renal biopsy indicated PIG, after the treatment of glucocorticoid, hydroxychloroquine and tacrolimus, the patient's clinical symptoms were relieved and urinary protein decreased.

Hepatitis B virus X protein promotes podocyte pyroptosis in hepatitis B virus-associated glomerulonephritis by down-regulating microRNA -223 targeting NLRP3 inflammasome / 中华肾脏病杂志

Objective:To investigate the potential function and related mechanism of microRNA-223 (miRNA-223) in the podocyte pyroptosis of hepatitis B virus (HBV)-associated glomerulonephritis induced by HBV X protein (HBx).Methods:HBx-overexpressing lentivirus was transfected into human renal podocytes to mimic the pathogenesis of HBV-GN. Real-time fluorescence quantitative PCR and Western blotting experiments were used to detect the mRNA and protein expression of pyroptosis-related proteins [nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1], and inflammatory factors (interleukin-1β and interleukin-18), respectively.TUNEL staining and flow cytometry were used to detect the number of pyroptosis cells. Immunofluorescence staining was used to detect the expression of podocytes biomarkers desmin and nephrin; Hoechst 33342 staining was used to observe the morphological and quantitative changes of podocyte nuclei. Enzyme-linked immunosorbent assay was used to measure caspase-1 activity. The dual luciferase reporter gene assay was used to verify the downstream target of miRNA-223. Podocytes were divided into the following nine groups: control group (no special treatment), empty plasmid group (transfected with empty plasmid), HBx overexpression group (transfected with HBx overexpression lentivirus), HBx overexpression+miRNA-223 mimic group (transfected with HBx overexpression lentivirus and miRNA-223 mimic), HBx overexpression+miRNA-223 inhibitor group (transfected with HBx overexpression lentivirus and miRNA-223 inhibitor), HBx overexpression+miRNA-223 mimic+NLRP3 group (transfected with HBx overexpression lentivirus, miRNA-223 mimic and NLRP3 overexpression plasmid), HBx overexpression+miRNA-223 mimic+ NLRP3 siRNA group (transfected with HBx overexpression lentivirus, miRNA-223 mimic and NLRP3 siRNA), HBx overexpression+miRNA-223 inhibitor+NLRP3 group (transfected with HBx overexpression lentivirus, miRNA-223 inhibitor and NLRP3 overexpression plasmid), HBx overexpression+miRNA-223 inhibitor+NLRP3 siRNA group (transfected with HBx overexpression lentivirus, miRNA-223 inhibitor and NLRP3 siRNA).Results:miRNA-223 was down-regulated in HBx overexpression group compared with the control group ( P < 0.05). TUNEL and immunofluorescence staining showed that NLRP3 knockdown attenuated podocyte injury and pyroptosis induced by HBx overexpression ( P < 0.05). Dual luciferase reporter gene assay demonstrated that NLRP3 was one of the downstream targets of miRNA-223. Rescue experiments revealed that NLRP3 overexpression weakened the protective effect of miRNA-223 in podocyte injury ( P < 0.05). The addition of miRNA-223 mimic and NLRP3 siRNA decreased the expression of NLRP3 inflammasome and cytokines, and reduced the number of pyroptosis cells induced by HBx overexpression (all P < 0.05); The addition of miRNA-223 inhibitor and NLRP3 overexpression plasmid significantly increased the expression of NLRP3 inflammasome and cytokines, caspase-1 activity, and the number of pyroptosis cells (all P < 0.05). Conclusion:HBx may promote podocyte pyroptosis of HBV-GN via downregulating miRNA-223 targeting NLRP3 inflammasome, suggesting that miRNA-223 is expected to be a potential target for the treatment of HBV-GN.

MicroRNA-26a-5p protects against podocyte injury via inhibiting TRPC6 expression in diabetic kidney disease / 中华肾脏病杂志

Objective:To investigate the protective effect and potential mechanisms of microRNA-26a-5p (miR-26a-5p) on podocyte injury in diabetic kidney disease (DKD).Methods:(1) In vivo experiment: Four-week-old db/db mice were divided into db/db group, db/db+agomir-NC group and db/db+miR-26a-5p agomir group according to random number table method, with 10 mice in each group, and 10 db/m mice of the same week-old were set as normal control group. At the age of 10 weeks, pathological changes were observed through light and electron microscopy. Kidney weight/body weight (KW/BW), urinary albumin to creatinine ratio (ACR), fasting blood glucose (FBG) and other biochemical indicators were also detected. The position and expression of miR-26a-5p in kidney tissue were determined through fluorescence in situ hybridization and quantitative real-time PCR, while the expressions of transient receptor potential cation channel-6 (TRPC6) and Nephrin in kidney tissue were determined by Western blotting and immunohistochemistry. (2) In vitro experiment: The immortalized mouse podocytes (MPC5) were divided into 5 groups: normal glucose group, high mannitol group, high glucose group, high glucose+miR-26a-5p mimic group, and high glucose+mimic-NC group. The expressions of miR-26a-5p, TRPC6 and Nephrin were detected. Luciferase reporter assay was conducted to research the relationship of miR-26a-5p and TRPC6. Results:(1) In vivo experiment: Compared with db/m group, db/db mice exhibited lower KW/BW and disrupted conditions of ACR, FBG, total cholesterol, triglycerides and low density lipoprotein cholesterol (all P<0.01). Increased glomeruli volume, more extracellular matrix deposition, thicker basement membrane and more foot process fusion were observed by light and electron microscope. Increased expression of TRPC6 protein as well as decreased expression of Nephrin protein and miR-26a-5p were detected in kidney tissues of db/db mice ( P<0.05). Compared with db/db+agomir-NC group, db/db mice transfected by miR-26a-5p agomir exhibited less albuminuria, with less protein expression of TRPC6 and more Nephrin in kidney tissue (all P<0.05). (2) In vitro experiment: Compared with normal glucose group, high glucose-treated podocytes exhibited increased expression of TRPC6 ( P<0.05), as well as decreased expression of Nephrin ( P<0.05) and miR-26a-5p ( P<0.01). Compared with high glucose+mimic-NC group, lower expression of TRPC6 and higher expression of Nephrin were detected in podocytes transfected by miR-26a-5p mimic (both P<0.05). Luciferase reporter assay confirmed that miR-26a-5p could regulate the expression of TRPC6 precisely. Conclusions:The expression of miR-26a-5p in podocytes is down-regulated in the context of high glucose and miR-26a-5p protects podocytes from injury via inhibiting the expression of TRPC6 in DKD.

The role of podocyte autophagy and endoplasmic reticulum stress in diabetic kidney disease / 中华危重病急救医学

Diabetic kidney disease (DKD) is one of the serious complications of diabetes mellitus, and it has become the leading cause of chronic renal failure in China. Podocytes are highly differentiated epithelial cells and are the important part of the glomerular filtration barrier. Apoptosis and shedding of podocytes, foot process fusion and decreased expression of slit membrane proteins can lead to proteinuria, which in turn affects the progression of DKD. Autophagy is an important process for eukaryotic cells to degrade cytoplasmic proteins and organelles,the increase of autophagy level helps to reduce podocytes damage. Endoplasmic reticulum stress (ERS) is the accumulation of misfolded proteins in cells. It allows the cells into stress state, and may be able to regulate cell damage in both directions. Autophagy and ERS are regulated by multiple signaling pathways and are considered to be closely related to the occurrence and development of DKD. This article explained some pathways and the role of podocyte autophagy and ERS in DKD, and the interaction between podocyte autophagy and ERS, which providing some potential targets for the treatment of DKD by interfering with podocyte autophagy and ERS.

Effect and Mechanism of Yishen Tongluo Prescription on miR-514a-5p/TNFSF15 Signaling Pathway in MN Rats / 中国实验方剂学杂志

ObjectiveTo explore the molecular mechanism of Yishen Tongluo prescription in inhibiting the apoptosis of glomerular podocytes in rats with membranous nephropathy （MN） based on the miR-514a-5p/tumor necrosis factor superfamily member 15 （TNFSF15） signaling pathway. MethodEighty SD rats were pre-immunized and injected with cationized bovine serum albumin （C-BSA） into the tail vein for inducing MN， and the successfully modeled MN rats were randomly divided into the model group， high-， middle-， and low-dose （26.44， 13.22， 6.61 g·kg-1） Yishen Tongluo prescription groups， and benazepril （10 mg·kg-1） group， with 10 rats in each group， and another 20 healthy rats were classified into the normal group. Rats in each group were gavaged with the corresponding drugs， once a day， for four successive weeks. After the administration， the 24-hour urine total protein （UTP） level， serum total cholesterol （TC）， triglyceride （TG）， albumin （ALB）， creatinine （SCr）， and urea nitrogen （BUN） levels were measured. The miR-514a-5p and TNFSF15 mRNA expression levels in the rat kidney tissue were detected by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the expression levels of podocyte marker proteins Nephrin， Podocin， Podocalyxin， Synaptopodin， TNFSF15， and podocyte apoptosis-related proteins B lymphocytoma-2 （Bcl-2）-related X protein （Bax）， Bcl-2-associated death promoter （BAD） protein， and B-cell lymphoma-extra large （Bcl-XL） by immunohistochemistry （IHC）. Western blot was used to detect the expression levels of TNFSF15， Bax， BAD， Bcl-2， and BCL-XL in the rat kidney tissue. The apoptosis rate of rat kidney tissue was measured using the in situ end labeling method （Tunnel）. ResultCompared with the normal group， the level of miR-514a-5p in the kidney tissue was significantly reduced （P<0.05）， and the TNFSF15 mRNA expression was significantly increased （P<0.05）. The expression levels of podocyte marker proteins Nephrin， Podocin， Podocalyxin， and Synaptopodin were down-regulated （P<0.05）. The protein expression levels of TNFSF15， Bax， and BAD were increased （P<0.05）， whereas the Bcl-2 and Bcl-XL protein expression levels were decreased （P<0.05）. The number of apoptotic cells diminished significantly （P<0.05）. Compared with the model group， the level of miR-514a-5p in the kidney tissue was significantly increased （P<0.05）， while the level of TNFSF15 mRNA was significantly decreased （P<0.05）. The expression levels of podocyte marker proteins Nephrin， Podocin， podocalyxin， and Synaptopodin were up-regulated （P<0.05）， whereas the TNFSF15， Bax， and BAD protein expression levels were down-regulated （P<0.05）. Bcl-2 and Bcl-XL protein expression levels rose （P<0.05）. The number of apoptotic cells significantly decreased （P<0.05）. ConclusionYishen Tongluo prescription reduces the apoptosis of rat kidney podocytes and alleviates the kidney injury of MN rats through the miR-514a-5p/TNFSF15 signaling pathway.

Effect of Danggui Buxuetang on Podocyte Injury in Diabetic Kidney Disease Rats： An Exploration Based on RIPK1/RIPK3/MLKL Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo observe the effect of Danggui Buxuetang on the podocyte injury and receptor-interacting protein kinase 1/receptor-interacting protein kinase3/mixed lineage kinase domain-like protein （RIPK1/RIPK3/MLKL） signaling pathway in diabetic kidney disease （DKD） ratsand to explore its possible mechanism against DKD. MethodEight of the 50 SD rats were randomly classified intoa normal group， and the remaining were fed a high-glucose and high-fat diet for six weeks and then intraperitoneally injected with 0.035 g·kg-1streptozotocin （STZ） for inducing type 2 diabetes. After successful modeling，they were randomized into the model group，high- and low-dose （1.44，0.72 g·kg-1） Danggui Buxuetang groups， and irbesartan （0.017 g·kg-1）group. After 20 weeks of drug intervention， the fasting blood glucose （FBG）， kidney index （KI），and urinary microalbumin-to-urine creatinine ratio （UACR）were detected in each group. The pathological changes in renal tissue were observed by hematoxylin-eosin （HE） staining， followed by the observation of ultrastructural changes in podocytes under the transmission electron microscope. The levels of tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in renal tissue of rats were determined by enzyme-linked immunosorbent assay （ELISA）， and the protein expression levels of RIPK1， RIPK3， and MLKL in rat kidney tissue by immunohistochemistry. The apoptosis rate of podocytes was detected by in situ nick end-labeling （TUNEL） assay. The mRNA expression levels of RIPK1， RIPK3， and MLKL in kidney tissue of rats were measured by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the protein expression levels of RIPK， RIPK3， and MLKL and podocyte marker Wilms tumor protein-1 （WT-1） in rat kidney tissue were assayed by Western blot. ResultCompared with the normal group， the model group exhibited elevated FBG， UACR， and KI （P<0.01）， glomerular hypertrophy， thickened basement membrane， increased extracellular matrix， mesangial hyperplasia， foot process fusion or loss， enhanced apoptosis in renal tissue， up-regulated TNF-α and IL-6 levels （P<0.01） and RIPK1/RIPK3/MLKL mRNA and protein expression （P<0.01）， and down-regulated WT-1 protein expression. Compared with the model group， Danggui Buxuetang high-dose group significantly reduced the levels of FBG， UACR， and KI， improved renal histopathology， podocyte loss， and apoptosis in renal tissue， down-regulated TNF-α and IL-6 levels and RIPK1/RIPK3/MLKL mRNA and protein expression （P<0.05， P<0.01）， and up-regulated WT-1 protein expression. ConclusionDanggui Buxuetang alleviates podocyte injury and delays the development of DKD possibly by regulating the RIPK1/RIPK3/MLKL signaling pathway.

Danggui Buxuetang Alleviates Oxidative Stress and Inflammation in Diabetic Kidney Disease Rats by Improving Mitochondrial Dysfunction of Podocytes / 中国实验方剂学杂志

ObjectiveTo investigate the intervention effect of Danggui Buxuetang on oxidative stress and inflammatory response in diabetic kidney disease （DKD） rats from its improvement of podocyte mitochondrial dysfunction. MethodSD rats were randomly divided into the control group and modeling group， and the ones in the latter group rats were fed a high-glucose and high-fat diet and then intraperitoneally injected with a small dose of streptozotocin （STZ） for inducing type 2 diabetes. The successfully modeled rats were randomized into the model group， high- and low-dose （1.44 and 0.72 g·kg-1） Danggui Buxuetang groups， and irbesartan （0.017 g·kg-1）group and gavaged with the corresponding drugs， while those in the normal and model groups with an equal volume of normal saline. After 20 weeks of drug intervention， the urinary microalbumin-to-urine creatinine ratio （UACR） and serum malondialdehyde （MDA） content and manganese superoxide dismutase （MnSOD） activity in each group were measured. The pathological changes in renal tissue were observed by Masson trichrome staining， and periodic acid-silver metheramine （PASM） staining， followed by the observation of ultrastructural changes in podocytes under the transmission electron microscope （TEM）. The expression level of reactive oxygen species （ROS） in rat kidney tissue was detected using a fluorescent probe dihydroethidium （DHE）. The protein expression levels of peroxisome proliferator-activated receptor γ -coactivator -1α （PGC-1α）， nucleotide-binding domain like receptor protein 3 （NLRP3）， and Wilms tumor protein-1 （WT-1） were measured by immunohistochemistry （IHC）， and the expression levels of NLRP3， interleukin-1β （IL-1β），and WT-1 in podocytes by immunofluorescence （IF） assay. The mRNA expression levels of PGC-1α and NLRP3 in the renal tissues were determined by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the protein expression levels of PGC-1α， MnSOD， NLRP3， and IL-1β were assayed by Western blot. ResultCompared with the normal group， the model group exhibited elevated UACR and MDA content， weakened MnSOD activity （P<0.01）， glomerular hypertrophy， thickened basement membrane， mesangial hyperplasia， increased extracellular matrix， K-W nodules， podocyte mitochondrial swelling， disordered mitochondrial cristae， foot process fusion or loss， vacuolization， increased ROS （P<0.01）， enhanced NLRP3 and IL-1β but diminished WT-1 expression in podocytes， down-regulated PGC-1α mRNA expression （P<0.01） and PGC-1α and MnSOD protein expression （P<0.01）， and up-regulated NLRP3 mRNA expression and NLRP3 and IL-1β protein expression （P<0.01）. Compared with the model group， Danggui Buxuetang high-dose group significantly decreased UACR and MDA， enhanced MnSOD activity （P<0.05， P<0.01）， improved renal histopathology and podocyte mitochondrial ultrastructure， decreased ROS （P<0.05， P<0.01） and NLRP3 and IL-1β expression in podocytes， enhanced WT-1 expression in podocytes， up-regulated the mRNA and protein levels of PGC-1α and MnSOD， and down-regulated the mRNA and protein levels of NLRP3 and IL-1β （P<0.05， P<0.01）. ConclusionDanggui Buxuetang alleviates oxidative stress， reduces inflammatory response， protects kidney， and delays the progression of DKD possibly by improving the mitochondrial dysfunction in podocytes of DKD rats.

Effect of Huangkui on mouse podocytes under high glucose environment / Efecto de Huangkui en podocitos de ratón en un entorno de glucosa alta

To explore a new underlying molecular mechanism of Huangkui Extract Powder (HKEP) in the alleviation of diabetic nephropathy (DN). Murine immortalized podocytes were divided into (i) normal glucose (NG, 5.6 mM), (ii) NG + HKEP (0.45 g/L), (iii) HG, and (iv) HG + HKEP (0.45 g/L) groups. MTT assay and flow cytometry were used to detect the podocyte proliferation, apoptosis and cell cycle. Cell viability was inhibited, and apoptosis increased in(iii) HG group compared with (i) NG group (p<0.05). mRNA and protein expression of nephrin and podocin significantly decreased in (iii) HG group compared with (i) NG group (p<0.05). When compared with (iii) HG group, (iv) HG + HKEP group had higher cell viability, lower apoptotic rate and higher mRNA and protein expression of nephrin and podocin (p<0.05). HKEP can attenuate HG-induced podocyte damage, which may be one of the mechanisms of HKEP for attenuating DN.

Explorar un nuevo mecanismo molecular subyacente del extracto del polvo de Huangkui (HKEP) en el alivio de la nefropatía diabética (ND). Los podocitos murinos inmortalizados se dividieron en (i) grupos de glucosa normal (NG, 5,6 mM), (ii) NG + HKEP (0,45 g/L), (iii) HG y (iv) HG + HKEP (0,45 g/L). Se utilizaron el ensayo MTT y la citometría de flujo para detectar la proliferación de podocitos, la apoptosis y el ciclo celular. La viabilidad celular se inhibió y la apoptosis aumentó en el grupo (iii) HG en comparación con el grupo (i) NG (p<0,05). La expresión de ARNm y proteínas de nefrina y podocina disminuyó significativamente en el grupo (iii) HG en comparación con el grupo (i) NG (p<0,05). En comparación con el grupo (iii) HG, el grupo (iv) HG + HKEP tuvo una mayor viabilidad celular, una tasa de apoptosis más baja y una expresión de ARNm y proteínas más altas de nefrina y podocina (p<0,05). HKEP puede atenuar el daño de los podocitos inducido por HG, que puede ser uno de los mecanismos de HKEP para atenuar la DN.

Effect and mechanism of PCSK9 on lipid homeostasis and cell damage of podocytes / 中华肾脏病杂志

Objective:To evaluate the effect of proprotein convertase subtilisin/kexin type 9 (PCSK9) on lipid homeostasis and cellular injury of podocytes, and to clarify its mechanism.Methods:Twelve-week old C57BL/6 wild-type mice ( n=10) and PCSK9 knockout ( PCSK9 KO) mice ( n=10) were selected as the animal models. The renal tissues were taken after perfusion through heart. Mouse podocytes were transfected with PCSK9 siRNA to downregulate PCSK9 expression. BODIPY 493/503 staining was performed for evaluating lipid accumulation, and standard transmission electron microscopy (TEM) was used to observe the foot process of podocytes, the shape of mitochondria and lipid droplet in podocytes. TUNEL staining was carried out to evaluate cell apoptosis in glomerulus. The parameters about mitochondria function (key enzymes such as PGC-1α, CPT-1 and Acox-1) and apoptosis were quantified through qPCR and western blotting. Results:The lipid accumulation in glomerulus of PCSK9 KO mice were more serious than controls. The expression of PGC-1α protein and PGC-1α, CPT-1 and Acox-1 mRNA in PCSK9 KO mouse kidney tissues were decreased than controls (all P<0.05), and mitochondria swelling and cristae disappearance in podocytes of PCSK9 KO mice were observed. In PCSK9 KO group, the foot process of podocytes partially fused and disappeared, and the apoptosis index increased compared with the control group ( P<0.05). In vitro, compared with the control group, the lipid accumulation was more significant, transcription level of key enzymes related to mitochondrial function was decreased, mitochondrial structure was damaged and the apoptosis index was increased in cultured podocyte PCSK9 siRNA group (all P<0.05). Conclusions:PCSK9 is involved in the lipid homeostasis of podocytes. The decrease of PCSK9 results in the increase of intracellular lipid accumulation, accompanied by the mitochondrial structure damage and disfunction of podocytes, and leads to cell apoptosis.

Role of mitofusion 2 in high glucose-induced endoplasmic reticulum stress and apoptosis of podocytes / 中华肾脏病杂志

Objective:To investigate the role of mitofusion 2 (Mfn2) in high glucose (HG)-induced endoplasmic reticulum stress (ERS) and apoptosis of podocytes.Methods:(1) Streptozocin was used to induce a diabetes mellitus (DM) rat model. Renal histopathological changes in rats were observed by HE staining. Expression of Mfn2 and CCAAT/enhancer-binding protein homologous protein (CHOP) in glomeruli was observed by immunohistochemistry. Protein levels of Mfn2, protein kinase RNA-like ER kinase (PERK), phospho(p)-PERK, and CHOP in glomeruli were analyzed by Western blotting. (2) Conditionally immortalized human podocytes (HPC) cultured in vitro were divided into control, mannitol (MA) and HG groups. Expression of Mfn2 was observed by immunofluorescence. Protein levels of Mfn2, p-PERK, PERK and CHOP in HPC were analyzed by Western blotting. Podocyte apoptosis in each group was evaluated by flow cytometry with AnnexinⅤ-PE/7AAD double staining method. (3) HPC were divided into control, HG, HG+Mfn2-Myc plasmid-transfected and HG+control plasmid-transfected groups. Protein levels of Mfn2, p-PERK, PERK and CHOP in HPC were analyzed by Western blotting. Expression of CHOP was observed by immunofluorescence. Mitochondrial membrane potential in each group was observed by mitochondrial membrane potential assay kit with JC-1. Podocyte apoptosis in each group was evaluated by flow cytometry with AnnexinⅤ-PE/7AAD double staining method. Results:(1) Compared with the control group, the glomerular mesangial matrix of the DM group rats was significantly proliferated, and the expression of Mfn2 was down-regulated with the expression of ERS-related proteins p-PERK/PERK and CHOP up-regulated (all P<0.05). (2) Compared with the control group, Mfn2 was down-regulated and p-PERK/PERK and CHOP were up-regulated in HPC of HG group (all P<0.05). Apoptosis of HPC was also increased in HG group. There was no significant difference in the above indicators between the control group and the mannitol group (all P>0.05). (3) Compared with the HG group, mitochondrial membrane potential of HPC was alleviated and apoptosis of HPC was decreased in HG+Mfn2-Myc plasmid-transfected group ( P<0.05). P-PERK/PERK and CHOP were down-regulated in HG+Mfn2-Myc plasmid-transfected group (both P<0.05). There was no significant difference in the above indicators between the HG group and the HG+control plasmid-transfected group (all P>0.05). Conclusions:Mfn2 down-regulation in HG-stimulated podocytes may induce ERS to increase apoptosis of podocytes. Up-regulation of Mfn2 can alleviate the HG-induced ERS and apoptosis in podocytes.

Period circadian clock 3 inhibits palmitic acid-induced oxidative stress and inflammatory factor secretion in podocytes / 中南大学学报(医学版)

OBJECTIVES@#High fat-induced podocyte injury is one of the important factors leading to obesity related nephropathy (ORG), but the mechanism is not clear. This study aims to explore the mechanism of period circadian clock 3 (PER3) in the oxidative stress and inflammation induced by palmitic acid (PA) in podocytes.@*METHODS@#The C57BL/6J mice were fed with chow and high-fat diet for 16 weeks. The PER3 expression in kidney tissues were detected in the normal body weight group and the obesity group. The PER3 mRNA and protein expression were detected after the podocytes were induced with different concentrations (0, 50, 150 and 300 μmol/L) of PA for 48 h. The PER3 mRNA and protein expression were detected after the podocytes were induced with 150 μmol/L PA for 0, 24, 36, and 48 h. Triglyceride (TG) levels were examined in the PA group, the adenovirus (ad)-PER3+PA group, and the siRNA-PER+PA group after the podocytes were transfected by Ad-PER3 or small interfering RNA (siRNA)-PER3 for 48 h and subsequently were induced with 150 μmol/L PA for 48 h. The differential gene expression was detected using RNA sequencing (RNA-seq) after podocytes were transfected by siRNA-PER3 (siRNA-PER3 group) and siRNA-control (siRNA-control group), respectively. The mRNA levels of nephrin, podocin, podocalyxin, podoplanin, superoxide dismutase 1 (SOD1), glutathione peroxidase 1 (GPX1), catalase (CAT), and the levels of malondialdehyde (MDA), glutathione (GSH), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and interleukin-2 (IL-2) were detected after podocytes were transfected with Ad-PER3 or Ad-control for 48 h and then they were induced by 150 μmol/L PA for 48 h.@*RESULTS@#The PER3 was down-regulated in the obesity group compared with the normal body weight group (@*CONCLUSIONS@#PER3 can decrease the PA-induced oxidative stress and inflammatory factor secretion via inhibiting the lipogenesis in podocytes.

Protective Mechanism of Danggui Shaoyaosan on Podocytes of Nephrotic Syndrome Rats Based on AngⅡ-TRPC6 Pathway / 中国实验方剂学杂志

Objective:To explore the protective effect and the mechanism of Danggui Shaoyaosan（DSS） on angiotensin Ⅱ （AngⅡ）/transient receptor potential cation channel 6 （TRPC6） pathway in nephrotic syndrome （NS） rats. Method:In animal experiments， doxorubicin （4 mg·kg^-1 for the 1^st week and 2 mg·kg^-1 for the 2^nd week） was injected twice to the tail vein of rats to induce NS model in 160 rats， which were then randomly divided into model group （normal saline）， losartan group （30 mg·kg^-1·d^-1）， and low-（4.3 g·kg^-1·d^-1）， medium-（8.6 g·kg^-1·d^-1）， and high-dose （17.2 g·kg^-1·d^-1） DSS groups. Besides， a normal group was also set. After intervention for four weeks， ultrastructure changes of the kidney were identified by transmission electron microscopy （TEM）. The 24-hour urine protein was detected by kits. Radioimmunoassay was used to detect the content of AngⅡ and Calcineurin （CaN） in plasma. Western blot was used to detect the protein expression of TRPC6， angiotensin Ⅱ type 1 receptor （AT1R）， podocyte slit diaphragm-specific protein （Nephrin）， and cysteine-aspartic acid protease-3 （Caspase-3） in the renal cortex. Immunohistochemistry was used to detect the expression of TRPC6 and AT1R in the slit diaphragm. In cell experiments， AngⅡ stimulated MPC5 podocytes. The cells were randomly divided into a normal group， an AngⅡ group， an AngⅡ+SAR7334 （TRPC6-specific inhibitor） group， an AngⅡ+5%DSS group， an AngⅡ+10%DSS group， and an AngⅡ+15%DSS group. Western blot was used to detect the protein expression of TRPC6， AT1R， Nephrin， and Caspase-3 in podocytes. Result:Compared with the normal group， the model group showed increased 24-hour urine protein content （<italic>P</italic><0.01） and AngⅡ and CaN in plasma （<italic>P</italic><0.01）， incomplete glomerular structure， the extensive fusion of podocyte process with elevated fusion rate （<italic>P</italic><0.01）， increased expression distribution of AT1R and TRPC6 in the renal cortex， and up-regulated protein expression of AT1R， TRPC6， and Caspase-3 in renal tissues （<italic>P</italic><0.01）， and reduced Nephrin protein expression （<italic>P</italic><0.01）. Compared with model group， the losartan group and the high-dose DSS group exhibited decreased 24-hour urine protein content （<italic>P</italic><0.01） and the content of AngⅡ and CaN in plasma （<italic>P</italic><0.01）， improved glomerular structure， reduced fusion rate of podocyte process （<italic>P</italic><0.01）， diminished expression distribution of TRPC6 and AT1R in the renal cortex， declining protein expression of AT1R， TRPC6 and Caspase-3 in renal tissues （<italic>P</italic><0.01）， and elevated Nephrin protein expression （<italic>P</italic><0.01）. Additionally， compared with the normal podocytes， AngⅡ-stimulated podocytes showed increased protein expression of AT1R， TRPC6 and Caspase-3 （<italic>P</italic><0.01）， and decreased expression of Nephrin （<italic>P</italic><0.01）. Compared with the AngⅡ group， the AngⅡ+SAR7334 group displayed reduced protein expression of AT1R， TRPC6， and Caspase-3 （<italic>P</italic><0.01） and increased protein expression of Nephrin （<italic>P</italic><0.01）. Conclusion:DSS can improve the pathological characteristics of NS presumedly by inhibiting the interaction between AngⅡ and TRPC6 in podocytes and improving the structural integrity of podocytes to repair the damage of glomerular molecular barrier and slow down the progression of NS-induced proteinuria.

mRNA Expression of Podocyte Associated Proteins in Peripheral Blood Mononuclear Cells of Type 2 Diabetes Mellitus Patients with and without Nephropathy.

Background: Diabetic nephropathy is the leading causeof End-Stage Renal Disease (ESRD) emerging indeveloped as well as developing countries, with thecomplicated pathogenesis. The study of expression ofthe genes related to kidney cells e.g. podocytes has beenshown to be associated with the condition, helping in theelucidation of pathogenesis of the disease. Previouslythe gene expression associated was studied in urinesamples. Material and Methods: In the present study, itwas attempted to analyze the mRNA expression ofpodocyte related genes viz. podocalyxin, podocin andsynaptopodin in Peripheral Blood Mononuclear Cells(PBMCs) in patients with diabetes with and withoutnephropathy in comparison with healthy controls byreverse transcriptase Polymerase Chain Reaction(PCR), followed by semi-quantitative PCR. Results:The expression of Synaptopodin (SYNPO) wasincreased in diabetics than the controls, while nosignificant difference was found for Podocalixyn(PODXL) and Podocin (NPHS2). The expression ofPODXL and NPHS2 was significantly up-regulated;SYNPO was unaltered in microalbuminuric patientsthan healthy controls. PODXL and SYNPO wereincreased significantly in nephropathy subjects thancontrols, with no significant change in NPHS2. Theexpression of only PODXL was found to be upregulated in microalbuminuric patients as compared toT2DM patients without nephropathy. PODXL, SYNPOwere significantly up-regulated and NPHS2 wassignificantly down-regulated in nephropathy subjects ascompared to T2DM patients without nephropathy. Asignificant down-regulation was found for NPHS2expression in nephropathy patients than microalbuminuric patients of T2DM with nephropathy.Conclusion: The detection of gene expression of theseproteins can be used as an early marker for the detectionof development of nephropathy in T2DM patients andpreventive measures can be taken to prolong the onsetof nephropathy in these patients, increasing the lifeexpectancy.

Aspirin intervenes in hyperlipidemia kidney damage by blocking endoplasmic reticulum stress in podocytes / 中华肾脏病杂志

Objective@#To investigate the effects and underlying mechanisms of aspirin on endoplasmic reticulum stress in podocytes induced by hyperlipemia.@*Methods@#Cultured podocytes were divided into four groups: control group, aspirin (100 μg/ml) group, oxidized low density lipoprotein (ox-LDL, 100 μg/ml) group, aspirin+ox-LDL group. The expression of protein kinase R-1ike endoplasmic reticulum kinase (PERK), eukaryotic translation initiation factor 2α (eIF2α), activating transcription factor-4 (ATF4) and CAAT/enhancer binding protein homologous protein (CHOP) at 6 h, 12 h, 24 h, 48 h were evaluated by real-time PCR. The related proteins of p-PERK and p-eIF2α at 24 h and ATF4 at 12 h were evaluated by Western blotting, respectively.@*Results@#The expressions of PERK, eIF2α peaked at 24 h, while ATF4 and CHOP peaked at 12 h in ox-LDL group and aspirin+ox-LDL group. Compared with control group, the expressions of PERK, eIF2α, ATF4 and CHOP were significantly higher in ox-LDL group at each times (all P<0.05). Compared with ox-LDL group, the expressions of the above indicators were significantly lower in aspirin+ox-LDL group at each times (all P<0.05). At 24 h, compared with control group, the expressions of p-PERK and p-eIF2α were significantly higher in ox-LDL group (both P<0.05). Compared with ox-LDL group, the expressions of p-PERK and p-eIF2α were significantly lower in aspirin+ox-LDL group (both P<0.05). At 12 h, the expression of ATF4 protein in each group was similar to that of mRNA. There were no significant difference in the expressions of all indicators between aspirin group and control group.@*Conclusions@#Hyperlipidemia may cause endoplasmic reticulum stress in podocytes by inducing phosphorylation of PERK and eIF2α, activating ATF4 transcription and inducing high expression of CHOP. Aspirin may partially block the PERK pathway, which may have protective effects for podocytes.

Protective effect of extractum trametes robiniophila murr on puromycin aminonucleoside-induced podocyte injury in vitro of mice and its mechanism / 吉林大学学报(医学版)

Objective: To investigate the effects of extractum trametes robiniophila murr on the filtration rate, motility and cytoskeleton rearrangement of the podocytes invitro of the puromycin aminonucleoside (PAN) - treated mice, and to clarify the protective effect of extractum trametes robiniophila murr on the podocyte injury and its mechanism. Methods: The podocytes cultured in vitro were randomly divided into control group, model group and test group. The podocytess in model group were treated with 50 mg · L-1 PAN for 24 h; the podocytess in test group were treated with 10 g · L-1 extraction trametes robiniophila murr for 1 h and then treated with 50 mg · L-1 PAN for 24 h. The filtration rate of podocytes to FITC-BSA was measured by two-compartment diffusion system; the scratch repair rate of podocytes was detected by cell scratch test, and the number of podocytes passing through the membrane was measured by Transwell cell migration test. Laser confocal microscope was used to observe the cytoskeleton rearrangement of podocyte cytoskeleton protein F-actin labeled with Invitrogen phalloidin directly. Results: Compared with control group, the FITC-BSA filtration rate of the podocytes in model group was increased significantly (P<0. 01); compared with model group, the FITC-BSA filtration rate of the podocytes in test group was decreased significantly (P<0. 01). Compared with control group, the scratch repair rate of podocytes and the number of transmembrane cells in model group were transmembrane (P<0. 05); compared with model group, the scratch repair rate of podocytes and the number of migration migration cells in test group were decreased significantly (P<0. 05). Compared with control group, the expression level of F-actin in the podocytes in model group was decreased significantly (P<0. 01), the rearrangement rate of F-actin was increased signifiantly (P< 0.01), and the structure of podocyte cytoskeleton was disordered; compared with model group, the expression level of F-actin in the podocytes in test group was increased significantly (P<0. 01), the rearrangement rate of F-actin was decreased significantly (P < 0. 01), and the skeleton rearrangement was alleviated obviously. Conclusion: Extractum trametes robiniophila murr could reduce the filtration rate of podocytes to BSA invitro under the pathological condition, and its possible mechanism is that extractum trametes robiniophila murr reduces the motility of podocytes and improve the rearrangement of podocyte cytoskeleton in vitro.

Effect of Tacrolimus on the expression of α-actinin-4 in podocytes induced by Puromycin aminonucleoside / 中华实用儿科临床杂志

Objective@#To investigate the effects of Tacrolimus(FK506) and Puromycin aminonucleoside(PAN) on apoptosis and expression of α-actinin-4 mRNA and protein in mouse glomerular podocytes in order to explore the protective effect of FK506 on podocytes.@*Methods@#Mouse glomerular podocytes were cultured in vitro, and the control group, PAN group and FK506 group were established.After 8 h, 24 h and 48 h of treatment, the cell morphology was observed and the apoptosis rate was detected.The cells were collected by real-time PCR and Western blot was used to detect the mRNA and protein expression of α-actinin-4.@*Results@#The cell body area of the PAN group was significantly smaller than that of the control group, and the cell area of the FK506 group was larger than that of the PAN group.There was no significant difference in the rate of podocyte apoptosis between those groups at 8 h (all P>0.05). At 24 h and 48 h, the apoptotic rate of podocytes in PAN group[(8.21±0.41)%, (16.32±0.17)%] were significantly higher than those in the control group[(4.28±0.35)%, (6.27±0.28)%], and the differences were significant (all P<0.05). The apoptosis rate of podocytes in FK506 group[(6.26±0.24)%, (13.32±0.24)%] were significantly lower than those in PAN group, and the differences were significant (all P<0.05). At 8 h, there was no significant difference in the expression of α-actinin-4 mRNA and protein(all P>0.05). The expression of mRNA (2.42±0.21, 3.78±0.25) and protein(0.77±0.04, 1.22±0.10) in the PAN group was significantly higher than mRNA(1.50±0.22, 2.15±0.15) and protein(0.44±0.03, 0.83±0.07) in the control group at 24 h and 48 h, and the differences were significant (all P<0.01). The expression of mRNA (1.65±0.24, 1.70±0.32) and protein (0.52±0.05, 0.56±0.07) in FK506 group was significantly lower than that of PAN group, and the differences were significant (all P<0.05).@*Conclusions@#FK506 can effectively inhibit the damage of PAN on podocytes and stabilize the expression of α-actinin-4, which provides a basis for the clinical application of FK506 in the treatment of glomerular diseases.

Effect of Danhong injection on expression of nephrin and podocin in podocyte of renal tissue in rats with membranous nephropathy / 国际中医中药杂志

Objective To observe the effect of Danhong injection on the expression of nephrin podocin protein and gene in the kidney of membranous nephropathy rats.Methods A total of 34 male clean level SD rats were divided at random into the normal control group (8 rats),model group (26 rates).The model group were injected the C-BSA into caudal vein to establish the model of the membranous nephropathy.After four week of succession of the models,two model rats were taken to confirm the success of the model.Another 24 models divided at random into model group,Losartan potassium treatment group and Danhong injection treatment group,8 in each group.In the losartan group,the losartan 40 mg/kg was administered,and the Danhong group was injected with 4 ml/kg of Danhong injection in the tail vein for 4 weeks.The rat urine was collected after the last administration,and 24 h urine protein was determined by spectrophotometer.The serum total protein,albumin,TC and TG levels were determined by automatic biochemical analyzer.The renal pathological changes were observed by HE staining.The expressions of nephrin,podocin and WT1 labeled podocytes were detected by immunohistochemical staining.The expressions of nephrin and podocin in renal tissue were detected by real-time quantitative PCR and Western blot,and the results were correlated.Results Compared with the model group,the content of serum albumin increased in the Danhong group (P＜0.01),24 h urine protein quantitation,TC,TG significantly decreased (P＜0.01).The expression of nephrin protein (1.12 ± 0.03 vs.0.57 ± 0.09),podocin protein (0.99 ± 0.04 vs.0.53 ± 0.08),nephrin mRNA (0.49 ± 0.08 vs.0.14 ± 0.02),podocin mRNA (0.50 ± 0.11 vs.1.18 ± 0.05) in Danhong group significantly increased (P＜0.01),and the number of podocytes labeled with WT1 (14.88％ ± 1.73％ vs.9.63％ ± 1.69％) significantly increased (P＜0.05).Correlation analysis showed that 24 h urine protein quantitation and expression of nephrin protein (r=-0.908),podocin protein (r=-0.916),nephrin mRNA (r=-0.930),podocin mRNA (r=-0.923).There was a negative correlation between serum albumin (r=-0.934) and podocyte count (r=-0.778) (P＜0.01),and positive correlation with TC (r=0.814) and TG (r=0.870) (P＜0.01).Conclusions The Danhong injection may reduce the urine protein of membranous nephropathy rats by up-regulating the expression of nephrin,podocin mRNA and protein in renal cells of membranous nephropathy.

Effect of Tacrolimus on the eXpression of α-actinin-4 in podocytes induced by Puromycin aminonucleoside / 中华实用儿科临床杂志

Objective To investigate the effects of Tacrolimus( FK506 )and Puromycin aminonucleoside ( PAN)on apoptosis and expression of α-actinin-4 mRNA and protein in mouse glomerular podocytes in order to ex-plore the protective effect of FK506 on podocytes. Methods Mouse glomerular podocytes were cultured in υitro,and the control group,PAN group and FK506 group were established. After 8 h,24 h and 48 h of treatment,the cell mor-phology was observed and the apoptosis rate was detected. The cells were collected by real-time PCR and Western blot was used to detect the mRNA and protein expression of α-actinin-4. Results The cell body area of the PAN group was significantly smaller than that of the control group,and the cell area of the FK506 group was larger than that of the PAN group. There was no significant difference in the rate of podocyte apoptosis between those groups at 8 h( all P>0. 05). At 24 h and 48 h,the apoptotic rate of podocytes in PAN group[(8. 21 ± 0. 41)%,(16. 32 ± 0. 17)%]were significantly higher than those in the control group[(4. 28 ± 0. 35)%,(6. 27 ± 0. 28)%],and the differences were significant(all P<0. 05). The apoptosis rate of podocytes in FK506 group[(6. 26 ± 0. 24)%,(13. 32 ± 0. 24)%] were significantly lower than those in PAN group,and the differences were significant(all P<0. 05). At 8 h,there was no significant difference in the expression of α -actinin -4 mRNA and protein( all P >0. 05 ). The expression of mRNA(2. 42 ± 0. 21,3. 78 ± 0. 25)and protein(0. 77 ± 0. 04,1. 22 ± 0. 10)in the PAN group was significantly higher than mRNA(1. 50 ± 0. 22,2. 15 ± 0. 15)and protein(0. 44 ± 0. 03,0. 83 ± 0. 07)in the control group at 24 h and 48 h,and the differences were significant(all P<0. 01). The expression of mRNA(1. 65 ± 0. 24,1. 70 ± 0. 32)and protein(0. 52 ± 0. 05,0. 56 ± 0. 07)in FK506 group was significantly lower than that of PAN group,and the differ-ences were significant(all P<0. 05). Conclusions FK506 can effectively inhibit the damage of PAN on podocytes and stabilize the expression of α-actinin-4,which provides a basis for the clinical application of FK506 in the treat-ment of glomerular diseases.

Active vitamin D3 plays a protective role in podocytes of diabetic rats by regulating autophagy activity / 中华内分泌代谢杂志

Objective To investigate the protective effect and mechanism of active vitamin D3 on podocyte injury in type 1 diabetic rats.Methods Animals were randomly divided into normal control group (NC group),diabetic nephropathy group (DN group),diabetes nephropathy plus active vitamin D3 group (DN + VD group).Random tail vein blood glucose was measured and 24 hours of urine was collected every 3 weeks to observe the dynamic changes of blood glucose and 24-hour urine volume and urinary albumin.Rats were sacrificed at the end of 18th week,the kidney weight to body weight ratio,serum creatinine,blood urea nitrogen,serum calcium,and serum phosphorus levels were measured.Pathological in glomeruli were observed by PAS staining.Immunohistochemistry and Western blotting were used to observe the expression of slit diaphragms proteins including Nephrin,Podocin,and vitamin D receptor protein VDR.The mRNA level of autophagy-related protein P62 was detected by realtime quantitative PCR,and expression of autophagy-related protein including LC3B/A,Beclin1,and P62 were detected by Western blotting.Ultrastructure of podocytes and autopbagosomes in podocytes were observed by electron microscopy.Results Levels of serum creatinine,blood urea nitrogen,and blood glucose in diabetic rats were higher than those in NC group (P＜0.05),but without significant difference between DN and DN+VD groups (P＞0.05).Compared with the DN group,the urinary protein and kidney weight to body weight ratio in the DN +VD group were significantly lower (P＜ 0.05).Mesangial matrix hyperplasia and basement membrane thickening were improved,and podocyte fusion and shedding were partially reversed.The expressions of Nephrin,Podocin,VDR,LC3B/A and Beclin1 were increased,and P62 mRNA and protein were down-regulated (P ＜ 0.05).The number of autophagosomes in podocytes increased.Besides,positive correlations were found between Nephrin and Beclin 1 (r =0.939 8,P＜0.05),as well as Nephrin and VDR (r=0.948 3,P＜0.05),and Beclin1 andVDR (r=0.9093,P＜0.05).Conclusion Active vitamin D3 inhibits the injury of diabetic nephropathy podocytes by up-regulating VDR expression and enhancing autophagy activity,thereby reducing proteinuria and delaying the development of diabetic nephropathy.

Mesenchymal Stem Cells Ameliorate Renal Inflammation in Adriamycin-induced Nephropathy

Mesenchymal stem cells (MSCs) ameliorate the renal injury in Adriamycin (ADR)-induced nephropathy, but the mechanisms underlying their efficacy remain incompletely understood. In this study, we demonstrated that MSCs increased the survival, recovered body weight loss, and decreased proteinuria and serum creatinine levels in ADR-treated mice. MSCs also prevented podocyte damage and renal fibrosis by decreasing the expression of fibronectin, collagen 1α1, and α-smooth muscle actin. From a mechanistic perspective, MSCs inhibited renal inflammation by lowering the expression of CCL4, CCL7, CCL19, IFN-α/β, TGF-β, TNF-α, and chitinase 3-like 1. In summary, our data demonstrate that MSCs improve renal functions by inhibiting renal inflammation in ADR-induced nephropathy.