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Abstract Renal involvement is one of the most severe morbidities of Fabry disease (FD), a multisystemic lysosomal storage disease with an X-linked inheritance pattern. It results from pathogenic variants in the GLA gene (Xq22.2), which encodes the production of alpha-galactosidase A (α-Gal), responsible for glycosphingolipid metabolism. Insufficient activity of this lysosomal enzyme generates deposits of unprocessed intermediate substrates, especially globotriaosylceramide (Gb3) and derivatives, triggering cellular injury and subsequently, multiple organ dysfunction, including chronic nephropathy. Kidney injury in FD is classically attributed to Gb3 deposits in renal cells, with podocytes being the main target of the pathological process, in which structural and functional alterations are established early and severely. This configures a typical hereditary metabolic podocytopathy, whose clinical manifestations are proteinuria and progressive renal failure. Although late clinical outcomes and morphological changes are well established in this nephropathy, the molecular mechanisms that trigger and accelerate podocyte injury have not yet been fully elucidated. Podocytes are highly specialized and differentiated cells that cover the outer surface of glomerular capillaries, playing a crucial role in preserving the structure and function of the glomerular filtration barrier. They are frequent targets of injury in many nephropathies. Furthermore, dysfunction and depletion of glomerular podocytes are essential events implicated in the pathogenesis of chronic kidney disease progression. We will review the biology of podocytes and their crucial role in regulating the glomerular filtration barrier, analyzing the main pathogenic pathways involved in podocyte injury, especially related to FD nephropathy.
Resumo O acometimento renal é uma das mais severas morbidades da doença de Fabry (DF), enfermidade multissistêmica de depósito lisossômico com padrão de herança ligada ao cromossomo X, decorrente de variantes patogênicas do gene GLA (Xq22.2), que codifica a produção de alfa-galactosidase A (α-Gal), responsável pelo metabolismo de glicoesfingolipídeos. A atividade insuficiente dessa enzima lisossômica gera depósitos de substratos intermediários não processados, especialmente do globotriaosilceramida (Gb3) e derivados, desencadeando injúria celular e, posteriormente, disfunção de múltiplos órgãos, incluindo a nefropatia crônica. A lesão renal na DF é classicamente atribuída aos depósitos de Gb3 nas células renais, sendo os podócitos o alvo principal do processo patológico, nos quais as alterações estruturais e funcionais são instaladas de forma precoce e severa, configurando uma podocitopatia metabólica hereditária típica, cujas manifestações clínicas são proteinúria e falência renal progressiva. Embora os desfechos clínicos tardios e as alterações morfológicas estejam bem estabelecidos nessa nefropatia, os mecanismos moleculares que deflagram e aceleram a injúria podocitária ainda não estão completamente elucidados. Podócitos são células altamente especializadas e diferenciadas que revestem a superfície externa dos capilares glomerulares, desempenhando papel essencial na preservação da estrutura e função da barreira de filtração glomerular, sendo alvos frequentes de injúria em muitas nefropatias. A disfunção e depleção dos podócitos glomerulares são, além disso, eventos cruciais implicados na patogênese da progressão da doença renal crônica. Revisaremos a biologia dos podócitos e seu papel na regulação da barreira de filtração glomerular, analisando as principais vias patogênicas envolvidas na lesão podocitária, especialmente relacionadas à nefropatia da DF.
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Objective To investigate the mechanism that Rubescensine A reduces the podocyte damage induced by high glucose(HG)through the autophagy pathway mediated by AMP activated protein kinase/silent information regulator 1(AMPK/SIRT1)pathway.Methods Human glomerular podocytes were cultured in vitro,and randomly divided into Control group(Con),HG group,hydroxychloroquine(HCQ)group,and Rapamycin(RAP)group.CCK-8 was used to detect cell viability.Western blotting was used to detect cell apoptosis and podocyte injury related protein expression in each group.The podocyte model induced by high glucose(HG)was treated with Rubescensine A(Rub A)at different concentrations and the optimal concentration was selected.Then,human glomerular podocytes were randomly divided into Con group,HG group,Rub A group,Compound C group,and Rub A+Compound C group.The expression of autophagy,AMPK/SIRT1 pathway related proteins were detected in each group.Results Compared with Con group,the podocyte viability and the protein expressions of Synaptopodin and Bcl-2 was significantly reduced(P<0.05),while the protein expressions of Desmin and Bax were significantly increased in HG group(P<0.05).Compared with the HG group,all indicators were relieved in RAP group.However,the levels of all indicators were worsened in HCQ group.Compared with Con group,the expression levels of Desminand Bax proteins in podocytes were significantly increased(P<0.05),and the podocyte viability,number of autophagosomes,the expression levels of Synaptopodin,Bcl-2,microtubule associated protein light chain 3(LC3)II/I,Beclin-1,p-AMPK/AMPK and SIRT1 proteins were significantly reduced in HG group(P<0.05).Compared with HG group and Rub A+Compound C group,the above indicators were improved in Rub A group.Compound C group reversed the protective effect of Rub A.Conclusion Rubescensine A can promote autophagy by activating AMPK/SIRT1 pathway,thereby reduce podocyte damage induced by high glucose.
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[Objective]To observe the effect of Xiaoyu Xiezhuo Drink on podocyte apoptosis and hypoxia inducible factor 1 alpha(HIF1α)expression in db/db diabetic kidney disease(DKD)model mice.[Methods]Six db/m mice were chosen as negative control group,eighteen db/db mice were chosen and divided into DKD model group,low dosage Xiaoyu Xiezhuo Drink group,high dosage Xiaoyu Xiezhuo Drink group,with six mice in each group.After gastric irrigation for twelve weeks,the urine was collected to test the levels of protein,β2-microglobulin(β2-MG),albumin/creatinine ratio(Acr),β2-microglobulin/creatinine ratio(β2-MG/Ucr);blood was collected to test the level of triglyceride(TG),total cholesterol(TC),albumin(Alb),blood urea nitrogen(BUN),serum creatinine(Scr);the kidney tissue was collected to observe the pathological change by light and electron microscope,and to test HIF1α,nephrin mRNA by Real-time polymerase chain reaction(RT-PCR).[Results]Compared with negative control group,the levels of urine protein,β2-MG,Acr,β2-MG/Ucr,serum TG,TC,BUN,Scr were increased(P＜0.01),serum Alb was decreased(P＜0.01);glomerular volume increased,capillary loops lobed,mesangial cells and matrix hyperplasia,interstitial inflammation and fibrosis increased,foot process fusion increased,basement membrane thickened;podocyte apoptosis was increased;expression of HIF1α mRNA was elevated(P＜0.01),and nephrin mRNA was descended in kidney tissue of DKD model group(P＜0.01).Compared with DKD model group,the level of urine protein,β2-MG,Acr,β2-MG/Ucr,serum TG,TC,BUN,Scr were decreased(P＜0.01),serum Alb was incresed(P＜0.01);the pathological changes of the kidney was improved;the apoptosis of podocyte was reduced;the expression of HIF1α mRNA was decreased(P＜0.01),and nephrin mRNA was incresed(P＜0.01)in the kidney tissue of varied dosage Xiaoyu Xiezhuo Drink groups.There was no statistical significance in the level of urine protein,β2-MG,Acr,β2-MG/Ucr,serum TG,TC,BUN,Scr,Alb,podocyte apoptosis,and HIF1α,nephrin mRNA in the kidney tissue between different dosage Xiaoyu Xiezhuo Drink groups(P＞0.05).[Conclusion]Xiaoyu Xiezhuo Drink could improve urinary protein,renal function,renal structure lesion and podocyte apoptosis in DKD mice,which perhaps by regulating the expression of HIF1α.
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ObjectiveTo explore the molecular mechanism of Qidi Tangshen prescription （QDTS） in regulating podocyte pyroptosis in diabetes nephropathy （DN）. MethodThrough in vivo experiment， db/db mice were divided into the model group， QDTS group （3.34 g·kg-1）， valsartan capsule group （10.29 mg·kg-1）， with db/m mice serving as the normal control. Each group consisted of 8 mice， and they underwent continuous intervention for 8 weeks. After the last administration， mice were euthanized， and kidney pathological changes were observed. Additionally， the expression levels of pyroptosis-related indicators， including NOD-like receptor protein 3 （NLRP3）， Gasdermin D protein （GSDMD）， and interleukin-1β （IL-1β） protein， were examined. Through in vitro experiment， mouse podocytes were divided into the normal glucose group （5.5 mmol·L-1 glucose）， high glucose group （35 mmol·L-1 glucose）， DMSO group （35 mmol·L-1 glucose+200 mg·L-1 DMSO）， and QDTS group （35 mmol·L-1 glucose+200 mg·L-1 QDTS freeze-dried powder）. After 48 hours of intervention， the expression levels of NLRP3， GSDMD， and IL-1β proteins were measured in podocytes. A drug-ingredient-target-disease interaction network for QDTS in the treatment of DN was constructed by network pharmacology methods. The key signaling pathways regulating podocyte pyroptosis were analyzed， and validation was conducted through in vivo and in vitro experiments. ResultCompared with normal group， glomerular hyperplasia and glomerular basement membrane thickening were observed in model group， and some segments were accompanied by obvious podocellular process fusion. The protein expressions of NLRP3， GSDMD and IL-1β in mouse kidney were increased， the protein expressions of mitogen-activated protein kinase 14 （MAPK14）， V-Rel reticuloendotheliosis virus oncogene homology A （RELA） and Caspase-8 in mouse kidney were increased （P<0.05）. Compared with model group， kidney pathological injury of mice in QDTS group was significantly reduced， and the expressions of NLRP3， GSDMD and IL-1β in kidney of mice in QDTS group and valsartan group were decreased （P<0.05）. The protein expressions of MAPK14， RELA and Caspase-8 in kidney of mice in QDTS group and valsartan group were decreased （P<0.05）. Network pharmacology results showed that there were 16 targets for QDTS to regulate DN cell pyrodeath， among which MAPK14， RELA and Caspase-8 were the key targets. Compared with normal glucose group， the protein expressions of NLRP3， GSDMD and IL-1β in high glucose group were increased （P<0.05）， and the protein expressions of MAPK14， RELA and Caspase-8 in mouse podocytes were increased （P<0.05）. Compared with high glucose group， the expressions of NLRP3， GSDMD and IL-1β in podocytes of mice in QDTS group were decreased （P<0.05）， and the expressions of MAPK14， RELA and Caspase-8 in podocytes of mice in QDTS group were decreased （P<0.05）. ConclusionQDTS reduces damage to DN podocytes， which is associated with its regulation of the MAPK14/RELA/Caspase-8 signaling pathway and inhibition of podocyte pyroptosis.
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ObjectiveTo investigate the protective mechanism of Qianyang Yuyin granules （QYYY） on aldosterone-induced podocyte injury. MethodA total of 30 C57BL/6J mice were randomly divided into five groups： control group， model group， QYYY low dose （QYYY-L） group， QYYY high dose （QYYY-H） group， and spironolactone （SPL） group， with six mice in each group. Except for the control group， mice were implanted with osmotic minipumps and injected continuously with aldosterone （300 μg·kg-1·d-1） to induce renal injury. The drug administration group was given low and high doses （2.6， 5.2 g·kg-1·d-1） of QYYY and SPL （18 mg·kg-1·d-1） for 28 days. The renal pathological changes of mice were observed by hematoxylin-eosin （HE） staining and Masson staining. The expression levels of Nephrin， Desmin， B-cell lymphoma-2 （Bcl-2）， Bcl-2-associated X （Bax）， cleaved Caspase-3， nuclear receptor subfamily 3 group C member 2 （NR3C2）， extracellular regulated protein kinases （ERK）， and phospho-ERK （p-ERK） in kidney tissue were detected by Western blot. The apoptosis levels of kidney tissue were detected by TdT-mediated dUTP nick and labeling （TUNEL） staining， and the superoxide dismutase （SOD） levels were detected. In vitro， the mice were divided into five groups： Control group， model group （aldosterone concentration of 200 nmol·L-1）， QYYY-L group， QYYY medium dose （QYYY-M） group， and QYYY-H group （25， 50， and 100 mg·L-1）. The effect of different concentrations of QYYY on the relative viability of aldosterone-induced podocytes was detected by cell proliferation and viability assay （CCK-8）. The expressions of Nephrin， Desmin， Bax， Bcl-2， cleaved Caspase-3， NR3C2， and p-ERK/ERK were detected by Western blot. AnnexinV-FITC/PI flow cytometry was used to detect the apoptosis levels of podocytes. Reactive oxygen species （ROS） in podocytes were observed by DCFH-DA. ResultCompared with the control group， the model group showed structural pathological changes and fibrotic conditions in the kidney， increased apoptosis levels （P<0.01）， and decreased SOD levels （P<0.01）. Aldosterone concentration at 200 nmol·L-1 showed a significant decrease in podocyte activity （P<0.05）. Podocytes in the model group showed structural pathological changes， disordered arrangement of intercellular microfilaments， increased apoptosis levels （P<0.01）， and increased intracellular ROS levels （P<0.01）. The protein expressions of Nephrin， Bcl-2， and p-ERK/ERK in kidney tissue and podocytes were decreased （P<0.05， P<0.01）. The protein expressions of Desmin， Bax， cleaved Caspase-3， and NR3C2 were increased （P<0.05， P<0.01）. Compared with the model group， QYYY alleviated the structural damage and fibrosis of the kidney， decreased the apoptosis levels （P<0.05， P<0.01）， and enhanced the SOD content of the kidney （P<0.05， P<0.01）. QYYY improved the activity of podocytes （P<0.05， P<0.01）， restored the foot process structure of podocytes， and decreased apoptosis levels （P<0.01） and ROS levels of podocytes （P<0.01）. The protein expressions of Nephrin， Bcl-2， and p-ERK/ERK in kidney tissue and podocytes were increased （P<0.05， P<0.01）， and the protein expressions of Desmin， Bax， cleaved Caspase-3， and NR3C2 were down-regulated （P<0.05， P<0.01）. ConclusionQYYY improves aldosterone-induced podocyte injury by regulating the NR3C2/ROS/ERK pathway.
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OBJECTIVE To investigate the effects of Taohong siwu decoction modified granules on podocyte epithelial- mesenchymal-transition （EMT） and renal fibrosis in diabetic kidney disease （DKD） model rats. METHODS Eight rats were selected as normal group （ordinary feed）； the remaining rats were given a high-glucose and high-fat diet combined with intraperitoneal injection of streptozotocin （35 mg/kg） to induce the DKD model. Model rats were randomly divided into model group， irbesartan group [positive control， 13.5 mg/（kg·d）] and modified Taohong siwu decoction group [6.48 g/（kg·d）]， with 8 rats in each group. All groups were given relevant medicine intragastrically， once a day， for 16 consecutive weeks. Twenty-four- hour urinary total protein （24 h UTP） was detected at the end of the 4th， 8th， 12th and 16th week of administration. After the last medication， the body mass， water intake， food intake， urine output， the levels of fasting blood glucose， serum creatinine （Scr） and blood urea nitrogen （BUN） as well as mRNA and protein expressions of P-cadherin， nephrin， α -smooth muscle actin （α-SMA）， Wilms’ tumor gene 1 （WT1）， transforming growth factor-β1（ TGF-β1） and type Ⅳ collagen （Col-Ⅳ） in renal tissue were determined. The pathological and morphological changes in renal tissue were observed and the thickness of the glomerular basement membrane was determined. RESULTS Compared with the model group， 24 h UTP of rats was significantly decreased in modified Taohong siwu decoction group since the 8th weekend （P＜0.05）； the body weight of rats increased significantly， but the amount of water intake and urine decreased significantly； Scr and BUN level， mRNA expression of α-SMA， mRNA and protein expressions of TGF-β1 and Col-Ⅳ were significantly reduced， while the mRNA expressions of P-cadherin， nephrin and WT1 were increased significantly （P＜0.05）； the protein deposition of α-SMA was reduced， protein depositions of P-cadherin， nephrin and WT1 were increased； the pathological damage and fibrosis of renal tissue were relieved； the thickness of glomerular basement membrane was decreased significantly （P＜0.05）. CONCLUSIONS Taohong siwu decoction modified granules can inhibit the EMT of podocyte in DKD model rats， and alleviate renal pathological damage and podocyte damage， thus protecting renal function， and delaying the process of renal fibrosis.
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OBJECTIVE To investigate the effects of Taohong siwu decoction modified granules on podocyte epithelial- mesenchymal-transition （EMT） and renal fibrosis in diabetic kidney disease （DKD） model rats. METHODS Eight rats were selected as normal group （ordinary feed）； the remaining rats were given a high-glucose and high-fat diet combined with intraperitoneal injection of streptozotocin （35 mg/kg） to induce the DKD model. Model rats were randomly divided into model group， irbesartan group [positive control， 13.5 mg/（kg·d）] and modified Taohong siwu decoction group [6.48 g/（kg·d）]， with 8 rats in each group. All groups were given relevant medicine intragastrically， once a day， for 16 consecutive weeks. Twenty-four- hour urinary total protein （24 h UTP） was detected at the end of the 4th， 8th， 12th and 16th week of administration. After the last medication， the body mass， water intake， food intake， urine output， the levels of fasting blood glucose， serum creatinine （Scr） and blood urea nitrogen （BUN） as well as mRNA and protein expressions of P-cadherin， nephrin， α -smooth muscle actin （α-SMA）， Wilms’ tumor gene 1 （WT1）， transforming growth factor-β1（ TGF-β1） and type Ⅳ collagen （Col-Ⅳ） in renal tissue were determined. The pathological and morphological changes in renal tissue were observed and the thickness of the glomerular basement membrane was determined. RESULTS Compared with the model group， 24 h UTP of rats was significantly decreased in modified Taohong siwu decoction group since the 8th weekend （P＜0.05）； the body weight of rats increased significantly， but the amount of water intake and urine decreased significantly； Scr and BUN level， mRNA expression of α-SMA， mRNA and protein expressions of TGF-β1 and Col-Ⅳ were significantly reduced， while the mRNA expressions of P-cadherin， nephrin and WT1 were increased significantly （P＜0.05）； the protein deposition of α-SMA was reduced， protein depositions of P-cadherin， nephrin and WT1 were increased； the pathological damage and fibrosis of renal tissue were relieved； the thickness of glomerular basement membrane was decreased significantly （P＜0.05）. CONCLUSIONS Taohong siwu decoction modified granules can inhibit the EMT of podocyte in DKD model rats， and alleviate renal pathological damage and podocyte damage， thus protecting renal function， and delaying the process of renal fibrosis.
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ObjectiveTo explore the molecular mechanism of modified Shengjiangsan in alleviating endoplasmic reticulum （ER） stress and reducing urinary protein in the rat model of diabetic nephropathy （DN）. MethodSeventy-five SD rats were randomized into normal， model， low-， medium-， and high-dose （4.37， 8.73， 17.46 g·kg-1， respectively） modified Shengjiangsan， and irbesartan （0.014 g·kg-1） groups， with 10 rats in each group. Rats were administrated with corresponding doses of medications or distilled water by gavage， once a day， for 8 consecutive weeks. After the last administration， the levels of glucose （GLU） in the blood， 24-hour urinary protein （24 h-UTP）， and superoxide dismutase （SOD）， malondialdehyde （MDA）， and glutathione peroxidase （GSH-Px） in the renal tissue were measured. Hematoxylin-eosin staining， periodic acid-Schiff staining， and transmission electron microscopy were employed to observe the pathological changes in rat kidneys. Immunohistochemistry was employed to measure the expression levels of nephrin， podocin， glucose-regulated protein 78 （GRP78）， C/EBP homologous protein （CHOP）， and activating transcription factor 4 （ATF4） in the kidneys of rats. Western blot was employed to measure the protein levels of silent information regulator 1 （Sirt1）， phosphorylated （p）-protein kinase RNA-like endoplasmic reticulum kinase （PERK）， and p-eukaryotic translation initiation factor 2 alpha （eIF2α） in rat kidneys. ResultCompared with the normal group， the modeling caused pathological damage to the kidneys， elevated the levels of GLU and 24 h-UTP （P<0.05）， up-regulated the protein levels of GRP78， CHOP， ATF4， p-PERK， and p-eIF2α （P<0.05）， and down-regulated the protein level of Sirt1 （P<0.05） in rat kidneys. Compared with the model group， modified Shengjiangsan and irbesartan lowered the GLU and 24 h-UTP levels （P<0.05）， alleviated the pathological damage in the renal tissue， down-regulated the protein levels of GRP78， CHOP， ATF4， p-PERK， and p-eIF2α （P<0.05）， and up-regulated the protein level of Sirt1 （P<0.05）. ConclusionModified Shengjiangsan up-regulates Sirt1 expression and inhibits phosphorylation of proteins in the PERK/eIF2α pathway to reduce ER stress and oxidative stress in the renal tissue， thus alleviating the pathological damage in the renal tissue and reducing urinary protein in DN rats.
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Steroid-resistant nephrotic syndrome (SRNS) is the second cause of chronic kidney disease in children. The SRNS has high risk of rapid progression to end-stage renal disease. With the advancement of high-throughput sequencing technology, more than 70 monogenic mutation having the Mendelian inheritance patterns are identified to be associated with SRNS. Most of these genes are involved in podocyte function. Accurate diagnosis of monogenic mutation in SRNS patients helps with guiding clinical treatment protocols and genetic counseling, avoiding the excessive use of steroids/immunosuppressive therapy, and opening up possibilities for targeted therapies in SRNS patients. In this article, our research team summarizes and generalizes the molecular mechanisms, genetic testing, and specific treatment for the major types of monogenic mutations associated with SRNS.
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ObjectiveTo observe the effects of Danggui Buxuetang on the mitochondrial fission and apoptosis of podocytes in the rat model of diabetic kidney disease （DKD） and to explore the protective effect and mechanism of Danggui Buxuetang on DKD rats. MethodSD rats were randomized into a modeling group （n=65， fed with a high-sugar and high-fat diet） and a normal group （n=10， fed with a normal diet）. After 6 weeks， the modeled rats were injected intraperitoneally with streptozotocin （STZ） for the modeling of type 2 diabetes mellitus （T2DM）. Sixty T2DM rats were randomized into model， irbesartan （0.014 g·kg-1）， and low-， medium-， and high-dose （0.36， 0.72， 1.44 g·kg-1， respectively） Danggui Buxuetang groups and administrated with corresponding drugs by gavage for 16 weeks. The levels of fasting blood glucose （FBG） and 24 h urinary protein （24 h UTP） were determined at the end of the 16th week. The pathological changes of the renal tissue were observed by hematoxylin-eosin and Masson staining. The mitochondrial ultrastructure of rat podocytes was observed by transmission electron microscopy. The level of reactive oxygen species （ROS） in the renal tissue of rats was measured by the fluorescent probe labeling of dihydroethidium （DHE）. The apoptosis of renal cells was detected by terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL）. The expression levels of Synaptopodin， Podocin， and cleaved caspase-3 in renal podocytes were detected by the immunohistochemical method （IHC）. Western blot was employed to determine the protein levels of A-kinase anchoring protein 1 （AKAP1）， phosphorylated dynamin-related protein 1 （p-Drp1）， mitofusin-2 （Mfn2）， B-cell lymphoma-2 （Bcl-2）， and Bcl-2-associated X protein （Bax）. ResultCompared with the control group， the model group showed elevated levels of FBG and 24 h UTP， mesangial hyperplasia， basement membrane thickening， mitochondrial swelling， mitochondrial crista breakage and disorder， and increased ROS and TUNEL-positive cells. In addition， the model group showcased down-regulated expression of Synaptopodin and Podocin， increased expression of cleaved Caspase-3， up-regulated protein levels of AKAP1 and p-Drp1 ， and down-regulated protein levels of Mfn2 and Bcl-2/Bax （P<0.01）. Compared with the model group， high-dose Danggui Buxuetang lowered the levels of FBG and 24 h UTP， alleviated the pathological injuries of the renal tissue and the mitochondrial injury of podocytes， decreased ROS and TUNEL-positive cells， promoted the expression of Synaptopodin and Podocin， inhibited the expression of cleaved Caspase-3， down-regulated the protein levels of AKAP1 and p-Drp1， and up-regulated the protein levels of Mfn2 and Bcl-2/Bax （P<0.05， P<0.01）. ConclusionDanggui Buxuetang may inhibit mitochondrial fission and apoptosis of podocytes and reduce urine protein by regulating the AKAP1/Drp1 pathway， thereby delaying the progression of DKD.
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ObjectiveTo explore the mechanism of Qidi Tangshen prescription （QDTS） in alleviating podocyte injury and reducing urinary protein in diabetic nephropathy （DN）. MethodUsing network pharmacology methods， we collected the chemical components and targets of QDTS， as well as the targets related to DN. Subsequently， we constructed a "drug-ingredient-target-disease" network for QDTS in the treatment of DN to systematically elucidate the mechanism. The db/db mice were assigned into the model， QDTS （3.34 g·kg-1）， and losartan capsules （10.29 mg·kg-1） groups， and db/m mice served as the normal group. Each group consisted of 8 mice， and they underwent continuous intervention for 8 weeks. After the last administration， mice were euthanized， and the urinary albumin excretion rate （UAER） and renal pathological changes were measured and observed. The expression levels of protein kinase B1 （Akt1）， hypoxia-inducible factor-1 alpha （HIF-1α）， phosphorylated B-cell lymphoma-extra-large （p-Bcl-xl）， as well as autophagy-related indicators microtubule-associated protein 1 light chain 3 （LC3）， ubiquitin-binding protein p62 （p62）， and autophagy-related gene 6 homolog （Beclin1）， were determined. Furthermore， mouse podocytes were divided into the normal glucose （5.5 mmol·L-1）， high glucose （35 mmol·L-1）， DMSO （35 mmol·L-1 glucose+200 mg·L-1 DMSO）， and QDTS （35 mmol·L-1 glucose+200 mg·L-1 QDTS freeze-dried powder） groups. After 48 h of intervention， the protein levels of Akt1， HIF-1α， p-Bcl-xl， LC3， p62， and Beclin1 in podocytes were measured. ResultQDTS had 34 active components acting on 143 targets in the treatment of DN， and 55 targets were related to autophagy， in which Akt1， HIF-1α， and Bcl-xl were the key targets. Compared with the normal group， mice in the model group exhibited significantly increased UAER， glomerular hypertrophy， deposition of blue collagen fibers， thickening of the glomerular basement membrane， and noticeable fusion of podocyte foot processes in some segments. Furthermore， the modeling up-regulated the protein levels of p-Akt1， HIF-1α， and p62 and down-regulating the protein levels of p-Bcl-xl， LC3， and Beclin1 in the renal tissue （P<0.05）. Compared with the model group， QDTS and losartan decreased UAER （P<0.05） and alleviated the pathological damage in the renal tissue. Moreover， QDTS and losartan down-regulated the protein levels of p-Akt1， HIF-1α， and p62 and up-regulated the protein levels of p-Bcl-xl， LC3， and Beclin1 in the renal tissue （P<0.05）. In comparison to the normal glucose group， the high glucose group displayed up-regulated protein levels of p-Akt1， HIF-1α， and p62 and down-regulated protein levels of p-Bcl-xl， LC3， and Beclin1 in podocytes （P<0.05）. Compared with the high glucose group， QDTS down-regulated the protein levels of p-Akt1， HIF-1α， and p62 and up-regulated the protein levels of p-Bcl-xl， LC3， and Beclin1 in podocytes （P<0.05）. ConclusionQDTS alleviates podocyte damage and reduced urinary protein in DN by regulating the Akt1/HIF-1α/Bcl-xl signaling pathway， thereby enhancing podocyte autophagy.
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GPCRs are the largest membrane protein receptor superfamily in the human body, with more than 800 isoforms, and approximately 35% of Food and Drug Administration-approved and marketed drugs currently target GPCRs for the treatment of a wide range of diseases, for heart failure (beta-adrenergic receptors), peptic ulcer (histamine receptors), prostate cancer (gonadotropin receptors), hypertension (adrenergic and angiotensin receptors), pain (opioid receptors), and bronchial asthma (beta2-adrenergic receptors) examples. Although the number of GPCRs is enormous, the signaling proteins downstream of them are limited, heterotrimeric G proteins (GPs) are key proteins that signal GPCRs, translate extracellular stimuli into intracellular responses by coupling to GPCRs and initiate multiple signaling events via downstream cascades. Podocytes are an important component of the glomerular filtration barrier, and their damage is a central event in proteinuria formation and progressive glomerulosclerosis. This article reviews the regulation of GPs, their signaling and their role in podocyte injury to provide a theoretical basis for scientific research and clinical treatment of this disease.
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IgA nephropathy is the most common primary glomerular disease in China. Its clinical manifestations are mainly proteinuria， hematuria， hypertension， edema， hyperuricemia， etc. Most patients have hidden onset. 30%-40% of patients develop into end stage renal disease 10-20 years after diagnosis and rely on dialysis or kidney transplantation to maintain their lives， which is extremely harmful. Proteinuria is a common clinical manifestation of this disease， and most patients have small-to-moderate amounts of proteinuria， while 10%-24% of patients have large amounts of proteinuria. Proteinuria is the main risk factor affecting the progression of renal function in IgA nephropathy. Podocytes are the terminal part of the glomerular filtration barrier， and various factors can affect the fusion and detachment of podocyte processes that occur after podocyte injury. They are common histological lesions in IgA nephropathy and are key factors leading to proteinuria and the continuous progression of the disease. At present， Western medicine lacks targeted treatment for podocyte injury， with limited intervention methods. Drugs such as glucocorticoids are often used for treatment， and there are many adverse reactions. Based on the physiological function of podocytes， pathological and physiological changes after injury， and histological morphology of this disease， it is believed that it is closely related to traditional Chinese medicine's "Xuanfu Theory" "Kidney Collateral Syndrome" "Collateral Disease Theory"， and "Dry Blood Theory". More and more studies have shown that traditional Chinese medicine， which has the characteristics of multiple links， pathways， and targets， has a significant therapeutic effect on podocyte injury in IgA nephropathy. It can protect podocytes and reduce proteinuria and has good application and research prospects. This article systematically summarizes the mechanism and morphological changes of podocyte injury in IgA nephropathy， the understanding of podocyte injury in traditional Chinese medicine theory， and the research progress in traditional Chinese medicine treatment of podocyte injury in IgA nephropathy， so as to provide a reference for further research and application of traditional Chinese medicine intervention in podocyte injury in IgA nephropathy.
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ObjectiveTo investigate the effect and mechanism of Dendrobium mixture （DMix）-containing serum on high glucose-induced podocyte injury in mice. MethodThe MPC5 mouse glomerular podocytes were cultured in vitro， and the optimal glucose concentration for modeling， modeling time， and concentration of DMix-containing serum for administration were determined. The cells were classified into normal （5.5 mmol·L-1 glucose+10% blank serum）， model （30 mmol·L-1 glucose+10% blank serum）， DMix-containing serum （30 mmol·L-1 glucose+10% DMix-containing serum）， ferroptosis inhibitor （Fer-1， 30 mmol·L-1 glucose+10% blank serum+1 μmol·L-1 Fer-1） groups. The corresponding kits were used to measure the levels of Fe2+ and lactate dehydrogenase （LDH） in cells. Enzyme-linked immunosorbent assay was employed to determine the content of glutathione （GSH） and lipid peroxide （LPO） in cells. Fluorescence probe was used to measure the reactive oxygen species （ROS） level. Real-time fluorescence quantitative polymerase chain reaction and Western blotting were employed to determine the mRNA and protein levels， respectively， of Wilms' tumor-1 （WT-1）， desmin， long chain acyl-CoA synthase 4 （ACSL4）， and glutathione peroxidase 4 （GPX4） in podocytes. ResultCompared with the blank group， the intervention with 30 mmol·L-1 glucose for 48 h reduced podocyte viability （P<0.01）， and the 10% DMix-containing serum showed the most significant improvement in podocyte viability （P<0.01）. Compared with the normal group， the model group presented elevated levels of Fe2+， LDH， LPO， and ROS， lowered GSH level， up-regulated mRNA and protein levels of desmin and ACSL4， and down-regulated mRNA and protein levels of WT-1 and GPX4 （P<0.01）. Compared with the model group， the DMix-containing serum lowered the Fe2+， LDH， LPO， and ROS levels， elevated the GSH level， down-regulated the mRNA and protein levels of desmin and ACSL4， and up-regulated the mRNA and protein levels of WT-1 and GPX4 in podocytes （P<0.05， P<0.01）. ConclusionDMix-containing serum exerts a protective effect on high glucose-induced podocyte injury by inhibiting ferroptosis.
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ObjectiveTo explore the underlying mechanism by which the Chinese medicine compound Yitangkang granule（YTK） treats diabetic kidney disease （DKD） by observing its effects on podocyte autophagy through the regulation of phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt）/forkhead transcription factor O1 （FoxO1） signaling pathway mediated by silent information regulator 1 （SIRT1） via advanced glycation end products （AGE）/receptor for AGE （RAGE） axis. MethodNinety-six 8-week-old healthy male SPF-grade Wistar rats were selected and randomly divided into blank control group （B）， model control group， high-dose YTK （40 g·kg-1）， medium-dose YTK （20 g·kg-1）， low-dose YTK （10 g·kg-1）， and Western medicine control （20 mg·kg-1 losartan） groups. The DKD rat model was established by high-fat diet feeding combined with intraperitoneal injection of streptozotocin. After successful modeling， the rats in each group received the corresponding treatments for eight weeks. The levels of superoxide dismutase （SOD）， malondialdehyde （MDA）， glutathione peroxidase （GSH-Px）， and catalase （CAT） were measured according to the instructions of the respective assay kits. Hematoxylin and eosin （HE） staining was used to observe pathological changes in kidney tissues. Immunohistochemistry was employed to detect the average optical density values of α-smooth muscle actin （α-SMA）， fibronectin （FN）， desmin， and nephrin. Western blot analysis was used to measure the expression levels of PI3K， phosphorylated PI3K （p-PI3K）， Akt， phosphorylated Akt （p-Akt）， RAGE， SIRT1， Caspase-3， and FoxO1 proteins in kidney tissues of DKD rats. ResultCompared with the blank control group， the model group showed significantly lower levels of SOD， GSH-Px， and CAT， and significantly higher levels of MDA （P<0.01）. The rats exhibited severe kidney damage. The positive expression of podocyte marker proteins α-SMA， FN， and desmin increased significantly， while nephrin and podocin significantly decreased （P<0.01）. The expression levels of PI3K， p-PI3K， Akt， p-Akt， RAGE， and Caspase-3 proteins were significantly elevated， while SIRT1 and FoxO1 protein levels were significantly reduced （P<0.01）. Compared with the model control group， rats in the YTK treatment groups showed significantly higher levels of SOD， GSH-Px， and CAT， and significantly lower levels of MDA in serum （P<0.01）. The degree of kidney damage was reduced to varying extents. The average optical density values of podocyte marker proteins α-SMA， FN， and desmin were significantly decreased， while nephrin and podocin significantly increased （P<0.01）. The expression levels of PI3K， p-PI3K， Akt， p-Akt， RAGE， and Caspase-3 in kidney tissues were significantly reduced， while SIRT1 and FoxO1 expression levels significantly increased （P<0.01）. The Chinese medicine groups demonstrated a clear dose-response trend. ConclusionYTK may alleviate kidney pathological damage， reduce proteinuria， and protect kidney function in DKD rats， thereby delaying the progression of DKD by improving podocyte autophagy through the AGE-RAGE axis-mediated SIRT1 regulation of the PI3K/Akt/FoxO1 signaling pathway. Additionally， a dose-response relationship was observed in the Chinese medicine groups.
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Steroid-resistant nephrotic syndrome (SRNS) is the second cause of chronic kidney disease in children. The SRNS has high risk of rapid progression to end-stage renal disease. With the advancement of high-throughput sequencing technology, more than 70 monogenic mutation having the Mendelian inheritance patterns are identified to be associated with SRNS. Most of these genes are involved in podocyte function. Accurate diagnosis of monogenic mutation in SRNS patients helps with guiding clinical treatment protocols and genetic counseling, avoiding the excessive use of steroids/immunosuppressive therapy, and opening up possibilities for targeted therapies in SRNS patients. In this article, our research team summarizes and generalizes the molecular mechanisms, genetic testing, and specific treatment for the major types of monogenic mutations associated with SRNS.
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ObjectiveTo observe the protective effect of Didang Xianxiong decoction on the kidneys of diabetic rats， its regulation on the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） signaling pathway， and its influence on podocyte apoptosis and explore the mechanism of Didang Xianxiong decoction in improving diabetic nephropathy. MethodThe diabetic model was established by a single intraperitoneal injection of streptozotocin （STZ） solution of 55 mg·kg-1. The successfully replicated model rats were randomly divided into the model group， Didang Xianxiong decoction group （8.10 g·kg-1）， Xiao Xianxiongtang group （4.05 g·kg-1）， Didangtang group （4.05 g·kg-1）， and alagebrium （ALT-711） group （3 mg·kg-1）， with six rats in each group. In addition， six rats were included in the blank group. After continuous administration for eight weeks， hematoxylin-eosin （HE） staining was used to observe the pathological changes in rats' kidney tissue. Masson staining was used to observe the degree of collagen deposition. Periodic acid-Schiff （PAS） staining was used to observe basement membrane lesions， and immunohistochemistry was used to detect the expression of phosphorylation （p）-PI3K and p-Akt proteins in rats' kidney tissue. The terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） method was used to detect podocyte apoptosis. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of PI3K and Akt in rats' kidney tissue. Western blot was used to detect the protein expression of PI3K， p-PI3K， Akt， p-Akt， B-cell lymphoma 2 （Bcl-2）， Bcl-2-associated X protein （Bax）， phosphorylation glycogen synthase kinase-3β （p-GSK-3β）， and Caspase-3 in the kidney tissue. ResultCompared with the normal group， the model group had compensatory expansion of glomeruli， proliferation of mesangial cells， a large amount of collagen deposition in the mesangial stroma， thickening of the basement membrane， decreased mRNA expression of PI3K and Akt， and inhibition of PI3K and Akt protein phosphorylation （P<0.01）. It also underwent enhanced apoptotic signaling， decreased expression of anti-apoptotic protein Bcl-2 （P<0.01）， and increased expression of Bax， p-GSK-3β， and Caspase-3 （P<0.01）. Compared with the model group， Didang Xianxiong decoction significantly improved kidney tissue pathology， increased mRNA expression of PI3K and Akt （P<0.01）， significantly up-regulated phosphorylation levels of PI3K and Akt proteins （P<0.01） and Bcl-2 expression （P<0.01）， downregulated the expression of Bax， p-GSK-3β， and Caspase-3 （P<0.01）， and weakened podocyte apoptotic signaling. ConclusionDidang Xianxiong decoction may promote the activation of the PI3K/Akt signaling pathway， inhibit podocyte apoptosis， and thus slow down the progression of diabetic nephropathy.
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Objective To investigate the role of lncRNA SNHG1 in homocysteine-induced pyroptosis of podocyte.Methods Cbs+/-mice were randomly divided into two groups:a normal diet group(ND)and a high me-thionine diet group(HMD).Western blotting was used to detect the protein expression levels of Caspase-1,Cleaved Caspase-1,and NLRP3.Mouse renal glomerular podocytes were cultured in vitro,and then assigned into a control group(Control,0 μmol/L Hcy)and a homocysteine intervention group(Hcy,80 μmol/L Hcy).Western blotting was used to detect the protein expression levels of Caspase-1,Cleaved Caspase-1,and NLRP3.Mouse renal glomerular podocyion group(OE-NC + Hcy)and the lncSNHG1 overexpression + homocysteine intervention group(OE-SNHG1 + Hcy)were also established.After 48 hours of intervention,Real-time fluorescence quantita-tive PCR was used to detect the expression of lncSNHG1 in podocytes after Hcy intervention.Western blot was used to detect the expressions of Caspase-1,Cleaved Caspase-3 and NLRP3.Immunofluorescence was used to de-tect the expression levels of GSDMD and GSDMD-N.ELISA was used to detect the contents of IL-1β and IL-18.Results(1)In the animal experiments,the expression levels of pyroptosis-related proteins Caspase-1,Cleaved Caspase-1,NLRP3,GSDMD,and GSDMD-N were all increased in the HMD group compared with the ND group.(2)In the cellular experiments,the expression levels of Caspase-1,Cleaved Caspase-1,NLRP3,GSDMD,and GSDMD-N were all increased in the Hcy group compared with the Control group,and the contents of pyroptosis-mediated inflammatory factors IL-1β and IL-18 were increased as well.(3)In the cellular experiments,the expres-sion of lncSNHG1 was increased in the Hcy group compared with the control group.After transduction with lnc-SNHG1 lentivirus,the expression of lncSNHG1 was increased in the OE-SNHG1 group,compared with the control group and the OE-NC group.(4)In the cellular experiments,the expressions of pyroptosis-related proteins Cas-pase-1,Cleaved Caspase-1,NLRP3,GSDMD,and GSDMD-N were increased compared with the OE-NC+Hcy group,and the contents of pyroptosis-mediated inflammatory factors IL-1β and IL-18 were increased in the OE-SNHG1+Hcy group.Conclusion These results indicate that lncSNHG1 may play a role in promoting Hcy induced podocytepyroptosis.
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Membranous nephropathy， an autoimmune kidney disease with glomerular podocyte injury as the core mechanism， is a common pathological type of adult nephrotic syndrome and has become the main cause of end-stage renal disease in China. Podocytes are terminally differentiated cells that play an important role in maintaining the structural and functional stability of glomeruli and are molecular barriers for protein filtration. Glomerular filtration membrane injury induced by podocyte injury is an important cause of massive proteinuria. Persistent or aggravated proteinuria may prolong the course of membranous nephropathy. It is believed that podocyte destruction in membranous nephropathy is mainly related to oxidative stress， autophagy dysregulation， abnormal expression of podocyte marker proteins， chronic inflammation， epithelial-mesenchymal cell transdifferentiation， and so on. At present， western medicine mostly uses immunosuppressants and hormones for treatment according to its pathological stage， but there are certain adverse reactions. Traditional Chinese medicine （TCM） has made some achievements in the prevention and treatment of membranous nephropathy. In recent years， studies have found that many Chinese medicines can affect the occurrence and development of membranous nephropathy in different links by acting on multiple targets in the human body， with manifest advantages. This paper overviewed the podocyte injury mechanism in membranous nephropathy and summarized the treatment of membranous nephropathy with Chinese medicine monomers， compounds， and Chinese patent medicines in intervening related target pathways， aiming to provide a basis for the clinical treatment， basic research， and targeted drug development of TCM against membranous nephropathy.
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The pathogenesis of the nephrotic syndrome is complex and the pathological types are diverse, so the minor symptoms in its early phases are difficult to detect. Renal biopsy is the gold indicator for the diagnosis of renal pathology and progression, but poor patient compliance shows, and the optimal treatment time is often delayed. Therefore, the discovery of biomarkers for early diagnosis and disease progression monitoring is of great clinical significance. In this study, doxorubicin-injured podocyte models were used to simulate human kidney disease at different stages of progression. LC-MS-based metabolomic technology combined with statistical methods was used to screen and identify the potential biomarkers associated with early injury or progression of podocytes. The results of cell viability, apoptosis tests and podocyte structural protein analysis showed that the model was successfully constructed, and the degree of podocyte injury was significantly different between the two modeling methods. According to VIP > 1 and P < 0.05 based on the orthogonal partial least squares discriminant analysis (OPLS-DA) model, nine differential metabolites reflecting early podocyte injury and twelve differential metabolites reflecting the injury progression were screened, respectively. ROC analysis was adopted to focus on the potential biomarkers that can reflecting the early podocyte injury including L-tryptophan, guanosine triphosphate (GTP), 5′-thymidylic acid (dTMP) and thymidine, and the biomarkers reflecting the injury progression of podocytes composed of L-phenylalanine, L-tyrosine acid, uridine 5′-diphosphate (UDP) and guanosine 5′-diphosphate (GDP) AUC > 0.85. It indicated that these eight metabolites may have high sensitivity and diagnostic ability. This study provides a reference for the research on biomarkers of progressive diseases.