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Renal Failure Dec 2024Diabetic kidney disease (DKD) is a common chronic microvascular complication of diabetes mellitus. Although studies have indicated the therapeutic potential of...
Diabetic kidney disease (DKD) is a common chronic microvascular complication of diabetes mellitus. Although studies have indicated the therapeutic potential of mesenchymal stem cells (MSCs) for DKD, the underlying molecular mechanisms remain unclear. Herein, we explored the renoprotective effect of placenta-derived MSCs (P-MSCs) and the potential mechanism of SIRT1/FOXO1 pathway-mediated autophagy in DKD. The urine microalbumin/creatinine ratio was determined using ELISA, and renal pathological changes were detected by special staining techniques. Immunofluorescence was used for detecting the renal tissue expression of podocin and nephrin; immunohistochemistry for the renal expression of autophagy-related proteins (LC3, Beclin-1, SIRT1, and FOXO1); and western blotting and PCR for the expression of podocyte autophagy- and pathway-related indicators. We found that P-MSCs ameliorated renal tubular injury and glomerular mesangial matrix deposition and alleviated podocyte damage in DKD rats. PMSCs enhanced autophagy levels and increased SIRT1 and FOXO1 expression in DKD rat renal tissue, whereas the autophagy inhibitor 3-methyladenine significantly attenuated the renoprotective effect of P-MSCs. P-MSCs improved HG-induced Mouse podocyte clone5(MPC5)injury, increased podocyte autophagy, and upregulated SIRT1 and FOXO1 expression. Moreover, downregulation of SIRT1 expression blocked the P-MSC-mediated enhancement of podocyte autophagy and improvement of podocyte injury. Thus, P-MSCs can significantly improve renal damage and reduce podocyte injury in DKD rats by modulating the SIRT1/FOXO1 pathway and enhancing podocyte autophagy.
Topics: Rats; Mice; Animals; Diabetic Nephropathies; Sirtuin 1; Autophagy; Kidney; Mesenchymal Stem Cells; Podocytes; Diabetes Mellitus
PubMed: 38234193
DOI: 10.1080/0886022X.2024.2303396 -
Inflammation Oct 2023The activation of nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome has been reported to importantly contribute to...
The activation of nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome has been reported to importantly contribute to glomerular inflammation and injury under different pathological conditions such as obesity. However, the mechanism mediating NLRP3 inflammasome activation in podocytes and subsequent glomerular injury remains poorly understood. Given that the ceramide signaling pathway has been reported to be implicated in obesity-related glomerulopathy (ORG), the present study was designed to test whether the ceramide-producing enzyme, acid sphingomyelinase (ASM), determines NLRP3 inflammasome activation and inflammatory exosome release in podocytes leading to glomerular inflammation and injury during ORG. In Smpd1/Podo mice, podocyte-specific overexpression of Smpd1 gene which encodes ASM significantly exaggerated high-fat diet (HFD)-induced NLRP3 inflammasome activation in podocytes and immune cell infiltration in glomeruli compared to WT/WT mice. Smpd1 gene deletion, however, blocked these pathological changes induced by HFD in Smpd1 mice. Accompanied with NLRP3 inflammasome activation and glomerular inflammation, urinary excretion of exosomes containing podocyte marker and NLRP3 inflammasome products (IL-1β and IL-18) in Smpd1/Podo mice on the HFD was much higher than that in WT/WT mice. In contrast, Smpd1 mice on the HDF had significantly lower urinary exosome excretion than WT/WT mice. Correspondingly, HFD-induced podocyte injury, glomerular sclerosis, and proteinuria were more severe in Smpd1/Podo mice, but milder in Smpd1 mice compared to WT/WT mice. Using podocytes isolated from these mice, we demonstrated that visfatin, a prototype pro-inflammatory adipokine, induced NLRP3 inflammasome activation and enrichment of multivesicular bodies (MVBs) containing IL-1β in podocytes, which was much stronger in podocytes from Smpd1/Podo mice, but weaker in those from Smpd1 mice than WT/WT podocytes. By quantitative analysis of exosomes, it was found that upon visfatin stimulation, podocytes from Smpd1/Podo mice released much more exosomes containing NLRP3 inflammasome products, but podocytes from Smpd1 mice released much less exosomes compared to WT/WT podocytes. Super-resolution microscopy demonstrated that visfatin inhibited lysosome-MVB interaction in podocytes, indicating impaired MVB degradation by lysosome. The inhibition of lysosome-MVB interaction by visfatin was amplified by Smpd1 gene overexpression but attenuated by Smpd1 gene deletion. Taken together, our results suggest that ASM in podocytes is a crucial regulator of NLRP3 inflammasome activation and inflammatory exosome release that instigate glomerular inflammation and injury during obesity.
Topics: Animals; Mice; Ceramides; Exosomes; Inflammasomes; Inflammation; Nicotinamide Phosphoribosyltransferase; NLR Family, Pyrin Domain-Containing 3 Protein; Obesity; Podocytes; Sphingomyelin Phosphodiesterase
PubMed: 37477734
DOI: 10.1007/s10753-023-01861-y -
Frontiers in Immunology 2023Podocyte injury, which involves the podocyte epithelial-mesenchymal transition (EMT) process, is a crucial factor contributing to the progression of diabetic nephropathy...
BACKGROUND
Podocyte injury, which involves the podocyte epithelial-mesenchymal transition (EMT) process, is a crucial factor contributing to the progression of diabetic nephropathy (DN) and proteinuria. Our study aimed to examine the protective properties of Angiopoietin-like protein 3 (Angptl3) knockout on podocyte damage and macrophage polarization in DN mice and podocytes treated with HG. Furthermore, we also sought to investigate the underlying molecular mechanism responsible for these effects.
METHODS
DN was induced in B6;129S5 mice through intraperitoneal injection of 40 mg/kg of streptozotocin (STZ). Subsequently, the changes in renal function, podocyte apoptosis, inflammatory factors (tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], and interleukin-1β [IL-1β]), IL-10, TGF-β1, IL-1Ra, IL-10Ra, and nephrin were evaluated. Moreover, we investigated the mechanism underlying the role of Angptl3 in macrophages polarization, podocyte injury, podocyte EMT.
RESULTS
Our findings revealed that Angptl3 knockout significantly attenuated STZ or HG-induced renal dysfunction and podocyte EMT. In both and studies, Angptl3 knockout led to (1) promote the transformation of M1 type macrophages into M2 type macrophages; (2) amelioration of the reduced expression of nephrin, synaptopodin, and podocin; (3) inhibition of NLRP3 inflammasome activation and release of IL-1β; and (4) regulation of α-SMA expression via the macrophage polarization. (5) After HG treatment, there was an increase in pro-inflammatory factors and foot cell damage. These changes were reversed upon Angptle knockdown.
CONCLUSION
Our study suggests that the knockout of Angptl3 alleviates podocyte EMT and podocyte injury by regulating macrophage polarization.
Topics: Animals; Mice; Angiopoietin-Like Protein 3; Apoptosis; Diabetes Mellitus; Diabetic Nephropathies; Epithelial-Mesenchymal Transition; Podocytes
PubMed: 37638046
DOI: 10.3389/fimmu.2023.1228399 -
American Journal of Physiology. Renal... Nov 2019Diabetic kidney disease (DKD) affects ∼40% of patients with diabetes and is associated with high mortality rates. Among different cellular targets in DKD, podocytes,... (Review)
Review
Diabetic kidney disease (DKD) affects ∼40% of patients with diabetes and is associated with high mortality rates. Among different cellular targets in DKD, podocytes, highly specialized epithelial cells of the glomerular filtration barrier, are injured in the early stages of DKD. Both clinical and experimental data support the role of preserved insulin signaling as a major contributor to podocyte function and survival. However, little is known about the key modulators of podocyte insulin signaling. This review summarizes the novel knowledge that intracellular lipids such as cholesterol and sphingolipids are major determinants of podocyte insulin signaling. In particular, the implications of these lipids on DKD development, progression, and treatment will be addressed.
Topics: Diabetic Nephropathies; Humans; Insulin; Lipid Metabolism; Podocytes; Signal Transduction
PubMed: 31545927
DOI: 10.1152/ajprenal.00379.2019 -
Nature Communications Jun 2024Recent studies have shown the crucial role of podocyte injury in the development of diabetic kidney disease (DKD). Deubiquitinating modification of proteins is widely...
Recent studies have shown the crucial role of podocyte injury in the development of diabetic kidney disease (DKD). Deubiquitinating modification of proteins is widely involved in the occurrence and development of diseases. Here, we explore the role and regulating mechanism of a deubiquitinating enzyme, OTUD5, in podocyte injury and DKD. RNA-seq analysis indicates a significantly decreased expression of OTUD5 in HG/PA-stimulated podocytes. Podocyte-specific Otud5 knockout exacerbates podocyte injury and DKD in both type 1 and type 2 diabetic mice. Furthermore, AVV9-mediated OTUD5 overexpression in podocytes shows a therapeutic effect against DKD. Mass spectrometry and co-immunoprecipitation experiments reveal an inflammation-regulating protein, TAK1, as the substrate of OTUD5 in podocytes. Mechanistically, OTUD5 deubiquitinates K63-linked TAK1 at the K158 site through its active site C224, which subsequently prevents the phosphorylation of TAK1 and reduces downstream inflammatory responses in podocytes. Our findings show an OTUD5-TAK1 axis in podocyte inflammation and injury and highlight the potential of OTUD5 as a promising therapeutic target for DKD.
Topics: Podocytes; Animals; MAP Kinase Kinase Kinases; Diabetic Nephropathies; Mice; Inflammation; Ubiquitination; Humans; Mice, Knockout; Male; Mice, Inbred C57BL; Phosphorylation; Diabetes Mellitus, Experimental; Ubiquitin-Specific Proteases; HEK293 Cells; Deubiquitinating Enzymes
PubMed: 38937512
DOI: 10.1038/s41467-024-49854-1 -
The Journal of Clinical Investigation Aug 2022With an aging population, kidney health becomes an important medical and socioeconomic factor. Kidney aging mechanisms are not well understood. We previously showed that...
With an aging population, kidney health becomes an important medical and socioeconomic factor. Kidney aging mechanisms are not well understood. We previously showed that podocytes isolated from aged mice exhibit increased expression of programmed cell death protein 1 (PD-1) surface receptor and its 2 ligands (PD-L1 and PD-L2). PDCD1 transcript increased with age in microdissected human glomeruli, which correlated with lower estimated glomerular filtration rate and higher segmental glomerulosclerosis and vascular arterial intima-to-lumen ratio. In vitro studies in podocytes demonstrated a critical role for PD-1 signaling in cell survival and in the induction of a senescence-associated secretory phenotype. To prove PD-1 signaling was critical to podocyte aging, aged mice were injected with anti-PD-1 antibody. Treatment significantly improved the aging phenotype in both kidney and liver. In the glomerulus, it increased the life span of podocytes, but not that of parietal epithelial, mesangial, or endothelial cells. Transcriptomic and immunohistochemistry studies demonstrated that anti-PD-1 antibody treatment improved the health span of podocytes. Administering the same anti-PD-1 antibody to young mice with experimental focal segmental glomerulosclerosis (FSGS) lowered proteinuria and improved podocyte number. These results suggest a critical contribution of increased PD-1 signaling toward both kidney and liver aging and in FSGS.
Topics: Aged; Animals; Endothelial Cells; Glomerulosclerosis, Focal Segmental; Humans; Kidney Glomerulus; Mice; Podocytes; Signal Transduction
PubMed: 35968783
DOI: 10.1172/JCI156250 -
Aging Jul 2023The decrease in the podocyte's lifespan and health-span that typify healthy kidney aging cause a decrease in their normal structure, physiology and function. The ability...
The decrease in the podocyte's lifespan and health-span that typify healthy kidney aging cause a decrease in their normal structure, physiology and function. The ability to halt and even reverse these changes becomes clinically relevant when disease is superimposed on an aged kidney. RNA-sequencing of podocytes from middle-aged mice showed an inflammatory phenotype with increases in the NLRP3 inflammasome, signaling for IL2/Stat5, IL6 and TNF, interferon gamma response, allograft rejection and complement, consistent with inflammaging. Furthermore, injury-induced NLRP3 signaling in podocytes was further augmented in aged mice compared to young ones. The NLRP3 inflammasome (NLRP3, Caspase-1, IL1β IL-18) was also increased in podocytes of middle-aged humans. Higher transcript expression for NLRP3 in human glomeruli was accompanied by reduced podocyte density and increased global glomerulosclerosis and glomerular volume. Pharmacological inhibition of NLRP3 with MCC950, or gene deletion, reduced podocyte senescence and the genes typifying aging in middle-aged mice, which was accompanied by an improved podocyte lifespan and health-span. Moreover, modeling the injury-dependent increase in NLRP3 signaling in human kidney organoids confirmed the anti-senescence effect of MC9950. Finally, NLRP3 also impacted liver aging. Together, these results suggest a critical role for the NLRP3 inflammasome in podocyte and liver aging.
Topics: Humans; Animals; Mice; Middle Aged; Podocytes; Inflammasomes; NLR Family, Pyrin Domain-Containing 3 Protein; Kidney Glomerulus; Aging
PubMed: 37487005
DOI: 10.18632/aging.204897 -
Advances in Clinical and Experimental... Dec 2019Diabetic nephropathy (DN) is the most common cause of end-stage renal disease (ESRD), both in the USA and in Europe; moreover, its incidence is rising worldwide. The... (Review)
Review
Diabetic nephropathy (DN) is the most common cause of end-stage renal disease (ESRD), both in the USA and in Europe; moreover, its incidence is rising worldwide. The main laboratory markers of DN progression are albuminuria and a reduction in glomerular filtration rates, although progression of the disease has been observed even in the absence of these biomarkers. Renal impairment, associated with diabetes, results from damage to the glomerular filtration barrier, at the level of highly differentiated glomerular epithelial cells: podocytes. These cells regulate glomerular filtration and many immunological processes occurring at this level. The earliest possible diagnosis of diabetic kidney disease (DKD) and implementation of intensive treatment offers the possibility of preventing or substantially delaying the onset of ESRD. In this article, we review various urinary biomarkers linked with glomerular podocyte cytophysiology as potentially sensitive diagnostic tools for the early detection of DKD. These biomarkers have predictive potential for assessing the progression toward end-stage nephropathy.
Topics: Albuminuria; Diabetic Nephropathies; Glomerular Filtration Rate; Humans; Kidney Glomerulus; Podocytes
PubMed: 31851794
DOI: 10.17219/acem/104534 -
Renal Failure 2023: Idiopathic membranous nephropathy is widely recognized as an autoimmune kidney disease that is accompanied by the discovery of several autoantibodies, and the antibody...
: Idiopathic membranous nephropathy is widely recognized as an autoimmune kidney disease that is accompanied by the discovery of several autoantibodies, and the antibody subclass in the circulation of patients with iMN is mainly IgG. However, the direct pathogenic effect of the containing anti-PLA2R IgG antibody on podocytes is not clear. A protein G affinity chromatography column was used to purify serum IgG antibodies. Containing anti-PLA2R IgG antibodies from iMN patients and IgG from healthy controls were also obtained. Based on the established podocyte culture system, purified IgG antibodies from the two groups were used to stimulate podocytes, and the expression of essential podocyte proteins (podocin), the levels of inflammatory cytokines in the cell supernatant, cytoskeletal disorders, and podocyte apoptosis were analyzed. Compared with that in the normal IgG group, the expression of podocin and podocin mRNA was reduced ( = 0.016 and = 0.005, respectively), the fluorescence intensity of podocin on the surface of podocytes was reduced, the cytoskeleton of podocytes was disordered and reorganized, and the ratio of podocyte apoptosis was increased in the iMN group ( = 0.008). The containing anti-PLA2R IgG antibody might have a direct damaging effect on podocytes in idiopathic membranous nephropathy.
Topics: Humans; Glomerulonephritis, Membranous; Podocytes; Autoantibodies; Kidney; Immunoglobulin G
PubMed: 37905942
DOI: 10.1080/0886022X.2023.2271986 -
Cells Apr 2021Vascular endothelial growth factor A (VEGFA) and its receptor VEGFR2 are the main targets of antiangiogenic therapies, and proteinuria is one of the common adverse... (Review)
Review
Vascular endothelial growth factor A (VEGFA) and its receptor VEGFR2 are the main targets of antiangiogenic therapies, and proteinuria is one of the common adverse events associated with the inhibition of the VEGFA/VEGFR2 pathway. The proteinuric kidney damage induced by VEGFR2 tyrosine kinase inhibitors (TKIs) is characterized by podocyte foot process effacement. TKI therapy promotes the formation of abnormal endothelial‒podocyte crosstalk, which plays a key role in TKI-induced podocyte injury and proteinuric nephropathy. This review article summarizes the underlying mechanism by which the abnormal endothelial‒podocyte crosstalk mediates podocyte injury and discusses the possible molecules and signal pathways involved in abnormal endothelial‒podocyte crosstalk. What is more, we highlight the molecules involved in podocyte injury and determine the essential roles of Rac1 and Cdc42; this provides evidence for exploring the abnormal endothelial‒podocyte crosstalk in TKI-induced nephrotoxicity.
Topics: Actin Cytoskeleton; Animals; Cell Movement; Endothelial Cells; Humans; Kidney; Podocytes; Protein Kinase Inhibitors
PubMed: 33921219
DOI: 10.3390/cells10040869