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1.
Life Sci ; 269: 119068, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33476631

RESUMO

AIMS: Podocyte apoptosis plays an important role in the pathogenesis of diabetic nephropathy (DN). Astragaloside IV (AS-IV) has been shown to protect against podocyte apoptosis. Here we aim to investigate the mechanism responsible for the protective effects of AS-IV. MAIN METHODS: Diabetic db/db mice and high glucose (HG)-cultured podocytes were treated with AS-IV. Renal function and histopathological changes were measured to evaluate the therapeutic effects of AS-IV against DN. Adenovirus-mediated Klotho overexpression, Klotho siRNA, and PPARγ inhibitor were applied in vitro to investigate the potential mechanism. The expression levels of mRNA and proteins were analyzed by qRT-PCR, western blot or immunofluorescence. Intracellular ROS and mitochondrial superoxide were detected by DHE and MitoSOx Red, respectively. Cell apoptosis was evaluated by TUNEL staining and flow cytometry. KEY FINDINGS: AS-IV improved renal function and ameliorated podocyte injury in db/db mice accompanied with enhanced Klotho expression in glomerular podocytes. In vitro, AS-IV inhibited HG-induced podocyte apoptosis and restored HG-inhibited Klotho expression, whereas Klotho knockdown abrogated the anti-apoptosis action of AS-IV. Further study showed that adenovirus-mediated Klotho overexpression enhanced Forkhead transcription factor O1 (FoxO1)-dependent antioxidant activity and attenuated HG-evoked oxidative stress and apoptosis. AS-IV prevented HG-induced FoxO1 inhibition and oxidative stress, whereas Klotho knockdown reversed these effects. Cotreatment with PPARγ inhibitor T0070907 abolished AS-IV-induced Klotho expression and anti-apoptosis action. SIGNIFICANCE: These data suggested that AS-IV attenuated podocyte apoptosis presumably by inhibiting oxidative stress via activating PPARγ-Klotho-FoxO1 signaling pathway, thereby ameliorating DN. This study provided new insights into the molecular mechanisms of AS-IV against DN.


Assuntos
Apoptose , Nefropatias Diabéticas/prevenção & controle , Proteína Forkhead Box O1/metabolismo , Glucuronidase/metabolismo , PPAR gama/metabolismo , Podócitos/efeitos dos fármacos , Saponinas/farmacologia , Triterpenos/farmacologia , Animais , Diabetes Mellitus Experimental/complicações , Nefropatias Diabéticas/etiologia , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Proteína Forkhead Box O1/genética , Regulação da Expressão Gênica , Glucose/metabolismo , Glucuronidase/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , PPAR gama/genética , Podócitos/metabolismo , Podócitos/patologia , Substâncias Protetoras , Transdução de Sinais
3.
Am J Physiol Renal Physiol ; 320(1): F97-F113, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-33308016

RESUMO

We recently reported that the enhanced susceptibility to chronic kidney disease (CKD) in the fawn-hooded hypertensive (FHH) rat is caused, at least in part, by a mutation in γ-adducin (ADD3) that attenuates renal vascular function. The present study explored whether Add3 contributes to the modulation of podocyte structure and function using FHH and FHH.Add3 transgenic rats. The expression of ADD3 on the membrane of primary podocytes isolated from FHH was reduced compared with FHH.Add3 transgenic rats. We found that F-actin nets, which are typically localized in the lamellipodia, replaced unbranched stress fibers in conditionally immortalized mouse podocytes transfected with Add3 Dicer-substrate short interfering RNA (DsiRNA) and primary podocytes isolated from FHH rats. There were increased F/G-actin ratios and expression of the Arp2/3 complexes throughout FHH podocytes in association with reduced synaptopodin and RhoA but enhanced Rac1 and CDC42 expression in the renal cortex, glomeruli, and podocytes of FHH rats. The expression of nephrin at the slit diaphragm and the levels of focal adhesion proteins integrin-α3 and integrin-ß1 were decreased in the glomeruli of FHH rats. Cell migration was enhanced and adhesion was reduced in podocytes of FHH rats as well as in immortalized mouse podocytes transfected with Add3 DsiRNA. Mean arterial pressures were similar in FHH and FHH.Add3 transgenic rats at 16 wk of age; however, FHH rats exhibited enhanced proteinuria associated with podocyte foot process effacement. These results demonstrate that reduced ADD3 function in FHH rats alters baseline podocyte pathophysiology by rearrangement of the actin cytoskeleton at the onset of proteinuria in young animals.


Assuntos
Citoesqueleto de Actina/metabolismo , Proteínas de Ligação a Calmodulina/metabolismo , Hipertensão/metabolismo , Podócitos/metabolismo , Proteinúria/metabolismo , Insuficiência Renal Crônica/metabolismo , Citoesqueleto de Actina/patologia , Animais , Pressão Arterial , Proteínas de Ligação a Calmodulina/genética , Adesão Celular , Linhagem Celular , Movimento Celular , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Adesões Focais/metabolismo , Adesões Focais/patologia , Hipertensão/genética , Hipertensão/patologia , Hipertensão/fisiopatologia , Integrinas/metabolismo , Masculino , Camundongos , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Podócitos/patologia , Proteinúria/genética , Proteinúria/patologia , Proteinúria/fisiopatologia , Ratos Endogâmicos , Ratos Transgênicos , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/patologia , Insuficiência Renal Crônica/fisiopatologia , Transdução de Sinais
4.
Metabolism ; 116: 154464, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33309714

RESUMO

OBJECTIVE: CER-001 is an HDL mimetic that has been tested in different pathological conditions, but never with LCAT deficiency. This study was designed to investigate whether the absence of LCAT affects the catabolic fate of CER-001, and to evaluate the effects of CER-001 on kidney disease associated with LCAT deficiency. METHODS: Lcat-/- and wild-type mice received CER-001 (2.5, 5, 10 mg/kg) intravenously for 2 weeks. The plasma lipid/ lipoprotein profile and HDL subclasses were analyzed. In a second set of experiments, Lcat-/- mice were injected with LpX to induce renal disease and treated with CER-001 and then the plasma lipid profile, lipid accumulation in the kidney, albuminuria and glomerular podocyte markers were evaluated. RESULTS: In Lcat-/- mice a decrease in total cholesterol and triglycerides, and an increase in HDL-c was observed after CER-001 treatment. While in wild-type mice CER-001 entered the classical HDL remodeling pathway, in the absence of LCAT it disappeared from the plasma shortly after injection and ended up in the kidney. In a mouse model of renal disease in LCAT deficiency, treatment with CER-001 at 10 mg/kg for one month had beneficial effects not only on the lipid profile, but also on renal disease, by limiting albuminuria and podocyte dysfunction. CONCLUSIONS: Treatment with CER-001 ameliorates the dyslipidemia typically associated with LCAT deficiency and more importantly limits renal damage in a mouse model of renal disease in LCAT deficiency. The present results provide a rationale for using CER-001 in FLD patients.


Assuntos
Apolipoproteína A-I/uso terapêutico , Nefropatias/tratamento farmacológico , Deficiência da Lecitina Colesterol Aciltransferase/tratamento farmacológico , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipídeos/sangue , Fosfolipídeos/uso terapêutico , Proteínas Recombinantes/uso terapêutico , Animais , Apolipoproteína A-I/farmacologia , Células Cultivadas , Modelos Animais de Doenças , Nefropatias/genética , Nefropatias/patologia , Deficiência da Lecitina Colesterol Aciltransferase/genética , Deficiência da Lecitina Colesterol Aciltransferase/metabolismo , Deficiência da Lecitina Colesterol Aciltransferase/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfatidilcolina-Esterol O-Aciltransferase/genética , Fosfolipídeos/farmacologia , Podócitos/efeitos dos fármacos , Podócitos/patologia , Podócitos/fisiologia , Proteínas Recombinantes/farmacologia
5.
Int J Mol Sci ; 21(24)2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33348903

RESUMO

Gangliosides constitute a subgroup of glycosphingolipids characterized by the presence of sialic acid residues in their structure. As constituents of cellular membranes, in particular of raft microdomains, they exert multiple functions, some of them capital in cell homeostasis. Their presence in cells is tightly regulated by a balanced expression and function of the enzymes responsible for their biosynthesis, ganglioside synthases, and their degradation, glycosidases. The dysregulation of their abundance results in rare and common diseases. In this review, we make a point on the relevance of gangliosides and some of their metabolic precursors, such as ceramides, in the function of podocytes, the main cellular component of the glomerular filtration barrier, as well as their implications in podocytopathies. The results presented in this review suggest the pertinence of clinical lipidomic studies targeting these metabolites.


Assuntos
Membrana Celular/metabolismo , Gangliosídeos/metabolismo , Barreira de Filtração Glomerular/metabolismo , Podócitos/patologia , Animais , Humanos , Podócitos/metabolismo
6.
J Toxicol Sci ; 45(11): 681-693, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33132242

RESUMO

Trichloroethylene (TCE) as a common organic solvent in industrial production can cause occupational medicamentosa-like dermatitis (OMDT) in some exposed workers. In addition to systemic skin damage, OMDT is also accompanied by severe kidney injury. Our previous studies show that complement (C) plays an important role in immune kidney injury caused by TCE. Specifically, C3 is mainly deposited on glomeruli. Recent studies have found that intracellular complement can be activated by cathepsin L (CTSL) and exert a series of biological effects. The purpose of this study was to explore where C3 on glomeruli comes from and what role it plays. A BALB/c mouse model of skin sensitization induced by TCE in the presence or absence of CTSL inhibitor (CTSLi,10 mg/kg). In TCE sensitization-positive mice, C3 was mainly expressed on podocytes and the expression of CTSL significantly increased in podocytes. Kidney function test and related indicators showed abnormal glomerular filtration and transmission electron microscopy revealed ultrastructure damage to podocytes. These lesions were alleviated in TCE/CTSLi positive mice. These results provide the first evidence that in TCE-induced immune kidney injury, intracellular complement in podocytes can be over-activated by CTSL and aggravates podocytes injury, thereby damaging glomerular filtration function. Intracellular complement activation and cathepsin L in podocytes may be a potential target for treating immune kidney injury induced by TCE.


Assuntos
Lesão Renal Aguda/etiologia , Lesão Renal Aguda/imunologia , Ativação do Complemento/efeitos dos fármacos , Podócitos/imunologia , Solventes/efeitos adversos , Tricloroetileno/efeitos adversos , Lesão Renal Aguda/fisiopatologia , Animais , Catepsina L/efeitos adversos , Complemento C3/metabolismo , Modelos Animais de Doenças , Feminino , Taxa de Filtração Glomerular , Glomérulos Renais/imunologia , Camundongos Endogâmicos BALB C , Podócitos/patologia , Podócitos/ultraestrutura
7.
Proc Natl Acad Sci U S A ; 117(40): 25026-25035, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32958645

RESUMO

In addition to their fundamental role in clearance, the kidneys release select molecules into the circulation, but whether any of these anabolic functions provides insight on kidney health is unknown. Using aptamer-based proteomics, we characterized arterial (A)-to-renal venous (V) gradients for >1,300 proteins in 22 individuals who underwent invasive sampling. Although most of the proteins that changed significantly decreased from A to V, consistent with renal clearance, several were found to increase, the most significant of which was testican-2. To assess the clinical implications of these physiologic findings, we examined proteomic data in the Jackson Heart Study (JHS), an African-American cohort (n = 1,928), with replication in the Framingham Heart Study (FHS), a White cohort (n = 1,621). In both populations, testican-2 had a strong, positive correlation with estimated glomerular filtration rate (eGFR). In addition, higher baseline testican-2 levels were associated with a lower rate of eGFR decline in models adjusted for age, gender, hypertension, type 2 diabetes, body mass index, baseline eGFR, and albuminuria. Glomerular expression of testican-2 in human kidneys was demonstrated by immunohistochemistry, immunofluorescence, and electron microscopy, while single-cell RNA sequencing of human kidneys showed expression of the cognate gene, SPOCK2, exclusively in podocytes. In vitro, testican-2 increased glomerular endothelial tube formation and motility, raising the possibility that its secretion has a functional role within the glomerulus. Taken together, our findings identify testican-2 as a podocyte-derived biomarker of kidney health and prognosis.


Assuntos
Biomarcadores/metabolismo , Rim/metabolismo , Proteoglicanas/genética , Proteômica , Afro-Americanos/genética , Aptâmeros de Peptídeos , Feminino , Taxa de Filtração Glomerular/genética , Humanos , Hipertensão/genética , Hipertensão/patologia , Rim/patologia , Testes de Função Renal , Glomérulos Renais/metabolismo , Masculino , Pessoa de Meia-Idade , Podócitos/metabolismo , Podócitos/patologia , Proteoglicanas/metabolismo
8.
Arch Biochem Biophys ; 692: 108541, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32781053

RESUMO

Podocytes are unique, highly specialized, terminally differentiated cells that form an essential, integral part of the glomerular filter. These cells limit the outside border of the glomerular basement membrane, forming a tight barrier that prevents significant protein loss from the capillary space. The slit diaphragm formed by podocytes is crucial for maintaining glomerular integrity and function. They are the target of injury in many glomerular diseases, including hypertension and diabetes mellitus. Accumulating studies have revealed that AMP-activated protein kinase (AMPK), an essential cellular energy sensor, might play a fundamental role in regulating podocyte metabolism and function. AMPK participates in insulin signaling, therefore controls glucose uptake and podocytes insulin sensitivity. It is also involved in insulin-dependent cytoskeleton reorganization in podocytes, mediating glomerular albumin permeability. AMPK plays an important role in the regulation of autophagy/apoptosis processes, which influence podocytes viability. The present review aimed to highlight the molecular mechanisms associated with AMPK that are involved in the regulation of podocyte function in health and disease states.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Nefropatias Diabéticas/enzimologia , Resistência à Insulina , Podócitos/enzimologia , Transdução de Sinais , Animais , Apoptose , Autofagia , Nefropatias Diabéticas/patologia , Humanos , Insulina/metabolismo , Glomérulos Renais/enzimologia , Glomérulos Renais/patologia , Podócitos/patologia
9.
BMC Nephrol ; 21(1): 326, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32753052

RESUMO

BACKGROUND: Coronavirus disease-2019 (COVID-19) is an ongoing pandemic which has affected over 12 million people across the globe. Manifestations in different organs systems are being reported regularly. Renal biopsy findings in hospitalized COVID-19 patients presenting solely with acute kidney injury (AKI) have recently been described in published literature in few case reports. The findings include diffuse acute tubular injury (ATI) along with the glomerular lesion of collapsing glomerulopathy (CG). However, nephrotic syndrome as the presenting complaint of COVID-19 has not been reported widely, neither has any other glomerular lesion other than CG. CASE PRESENTATION: We describe the kidney biopsy findings of two patients who had recent diagnoses of COVID-19 and presented with new-onset nephrotic syndrome. Renal biopsy in both patients showed ATI (as in previous reports) and distinct glomerular findings on light microscopy - that of minimal change disease (MCD) initially in one patient followed by CG in a subsequent biopsy and CG at the outset in the other patient. The electron microscopic findings in both patients were that of severe podocytopathy (diffuse and severe podocyte foot process effacement). CONCLUSION: Our cases highlight a novel clinical presentation of COVID-19 renal disease, not described before, that of new-onset nephrotic syndrome. While all published case reports describe CG as the glomerular pathology, we describe a non-CG pathology (MCD) in one of our cases, thereby adding to the repertoire of renal pathology described in association with COVID-19 patients. However, the exact mechanism by which podocyte injury or podocytopathy occurs in all such cases is still unknown. Optimal treatment options for these patients also remains unknown at this time.


Assuntos
Betacoronavirus , Infecções por Coronavirus/complicações , Túbulos Renais/patologia , Síndrome Nefrótica/patologia , Pneumonia Viral/complicações , Podócitos/patologia , Idoso , Biópsia , Humanos , Rim/patologia , Glomérulos Renais/patologia , Masculino , Pessoa de Meia-Idade , Nefrose Lipoide/etiologia , Nefrose Lipoide/patologia , Síndrome Nefrótica/etiologia , Pandemias
10.
Sci Rep ; 10(1): 9419, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32523052

RESUMO

Dominant and recessive mutations in podocalyxin (PODXL) are associated with human kidney disease. Interestingly, some PODXL mutations manifest as anuria while others are associated with proteinuric kidney disease. PODXL heterozygosity is associated with adult-onset kidney disease and podocalyxin shedding into the urine is a common biomarker of a variety nephrotic syndromes. It is unknown, however, how various lesions in PODXL contribute to these disparate disease pathologies. Here we generated two mouse stains: one that deletes Podxl in developmentally mature podocytes (Podxl∆Pod) and a second that is heterozygous for podocalyxin in all tissues (Podxl+/-). We used histologic and ultrastructural analyses, as well as clinical chemistry assays to evaluate kidney development and function in these strains. In contrast to null knockout mice (Podxl-/-), which die shortly after birth from anuria and hypertension, Podxl∆Pod mice develop an acute congenital nephrotic syndrome characterized by focal segmental glomerulosclerosis (FSGS) and proteinuria. Podxl+/- mice, in contrast, have a normal lifespan, and fail to develop kidney disease under normal conditions. Intriguingly, although wild-type C57Bl/6 mice are resistant to puromycin aminonucleoside (PA)-induced nephrosis (PAN), Podxl+/- mice are highly sensitive and PA induces severe proteinuria and collapsing FSGS. In summary, we find that the developmental timepoint at which podocalyxin is ablated (immature vs. mature podocytes) has a profound effect on the urinary phenotype due to its critical roles in both the formation and the maintenance of podocyte ultrastructure. In addition, Podxl∆Pod and Podxl+/- mice offer powerful new mouse models to evaluate early biomarkers of proteinuric kidney disease and to test novel therapeutics.


Assuntos
Nefropatias/metabolismo , Podócitos/metabolismo , Sialoglicoproteínas/metabolismo , Animais , Feminino , Glomerulosclerose Segmentar e Focal/metabolismo , Glomerulosclerose Segmentar e Focal/patologia , Heterozigoto , Humanos , Nefropatias/patologia , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Síndrome Nefrótica/metabolismo , Síndrome Nefrótica/patologia , Fenótipo , Podócitos/patologia , Proteinúria/metabolismo , Proteinúria/patologia , Puromicina Aminonucleosídeo/metabolismo
11.
BMC Med Genet ; 21(1): 137, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32590976

RESUMO

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disorder due to deficient alpha-galactosidase activity leading to intracellular glycosphingolipid accumulation. Multiple variants have been reported in the GLA gene coding for alpha-galactosidase, and the question of the pathogenicity of rare variants needs to be addressed, especially in patients with mild phenotypes. CASE PRESENTATION: The patient, a 37-year-old female, presented with a persistent proteinuria after an otherwise uncomplicated first pregnancy. Renal biopsy showed both mild mesangial IgA deposits, and a striking vacuolization of podocytes and tubular cells consistent with Fabry disease. On electron microscopy, discrete but characteristic pseudo-myelinic lamellar inclusions were observed in the podocytes' lysosomes. A more detailed physical examination revealed an angiokeratoma, and medical history ancient acroparesthesia. There was no cardiac or cerebral involvement of Fabry disease on magnetic resonance imaging. While blood enzymatic activity of alpha-ga lactosidase was normal in this patient, lysoGb3 was elevated (3 N), and a rare heterozygous variant called c.610 T > C was documented in GLA gene. The patient was treated with an ACE inhibitor, with a rapid decrease in proteinuria. After a 5-year follow-up, her renal function has remained normal, with mild proteinuria, and normal cardiac echography. CONCLUSIONS: We report and phenotypically describe the first case of a Fabry disease female patient carrying the GLA c.610 T > C variant associated with a renal-predominant clinical presentation.


Assuntos
Doença de Fabry/genética , Rim/patologia , Mutação/genética , alfa-Galactosidase/genética , Adulto , Doença de Fabry/fisiopatologia , Feminino , Humanos , Rim/fisiopatologia , Fenótipo , Podócitos/patologia
12.
Clin Sci (Lond) ; 134(11): 1245-1253, 2020 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-32501496

RESUMO

Chronic kidney disease (CKD) substantially reduces quality of life and leads to premature death for thousands of people each year. Dialysis and kidney organ transplants remain prevalent therapeutic avenues but carry significant medical, economic and social burden. Podocytes are responsible for blood filtration selectivity in the kidney, where they extend a network of foot processes (FPs) from their cell bodies which surround endothelial cells and interdigitate with those on neighbouring podocytes to form narrow slit diaphragms (SDs). During aging, some podocytes are lost naturally but accelerated podocyte loss is a hallmark of CKD. Insights into the origin of degenerative podocyte loss will help answer important questions about kidney function and lead to substantial health benefits. Here, approaches that uncover insights into podocyte mechanobiology are reviewed, both those that interrogate the biophysical properties of podocytes and how the external physical environment affects podocyte behaviour, and also those that interrogate the biophysical effects that podocytes exert on their surroundings.


Assuntos
Biofísica , Saúde , Nefropatias/patologia , Podócitos/patologia , Animais , Fenômenos Biomecânicos , Humanos , Estresse Mecânico
13.
Clin Sci (Lond) ; 134(12): 1305-1318, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32478397

RESUMO

Podocyte injury and loss contribute to proteinuria, glomerulosclerosis and eventually kidney failure. Recent studies have demonstrated that the loss of Kruppel-like factor 15 (KLF15) in podocytes increases the susceptibility to injury; however, the mechanism underlying the protective effects on podocyte injury remains incompletely understood. Herein, we showed that KLF15 ameliorates podocyte injury through suppressing NFAT signaling and the salutary effects of the synthetic glucocorticoid dexamethasone in podocyte were partially mediated by the KLF15-NFATc1 axis. We found that KLF15 was significantly reduced in glomerular cells of proteinuric patients and in ADR-, LPS- or HG-treated podocyets in vitro. Overexpression of KLF15 attenuated podocyte apoptosis induced by ADR, LPS or HG and resulted in decreased expression of pro-apoptotic Bax and increased expression of anti-apoptotic Bcl-2. Conversely, the flow cytometry analysis and TUNEl assay demonstrated that loss of KLF15 accelerated podocyte apoptosis and we further found that 11R-VIVIT, a specific NFAT inhibitor, and NFATc1-siRNA rescued KLF15-deficient induced podocyte apoptosis. Meanwhile, Western blot and RT-qPCR showed that the expression of NFATc1 was up-regulated in KLF15 silenced podocytes and reduced in KLF15 overexpressed podocytes. Mechanistically, ChIP analysis showed that KLF15 bound to the NFATc1 promoter region -1984 to -1861base pairs upstream of the transcription start site and the binding amount was decreased after treatment with LPS. The dual-luciferase reporter assay indicated that NFATc1 was a direct target of KLF15. In addition, we found that in vitro treatment with dexamethasone induced a decrease of NFATc1 expression in podocytes and was abrogated by knockdown of KLF15. Hence, our results identify the critical role of the KLF15-NFATc1 axis in podocyte injury and loss, which may be involved in mediating the salutary effects of dexamethasone in podocytes.


Assuntos
Glucocorticoides/uso terapêutico , Fatores de Transcrição Kruppel-Like/metabolismo , Fatores de Transcrição NFATC/metabolismo , Podócitos/metabolismo , Podócitos/patologia , Proteinúria/tratamento farmacológico , Proteinúria/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Dexametasona/farmacologia , Regulação para Baixo/efeitos dos fármacos , Doxorrubicina/farmacologia , Técnicas de Silenciamento de Genes , Inativação Gênica/efeitos dos fármacos , Glucocorticoides/farmacologia , Glucose/toxicidade , Humanos , Lipopolissacarídeos/farmacologia , Camundongos , Modelos Biológicos , Transdução de Sinais
14.
Am J Physiol Renal Physiol ; 318(6): F1377-F1390, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32308020

RESUMO

Ste20-like kinase SLK is critical for embryonic development and may play an important role in wound healing, muscle homeostasis, cell migration, and tumor growth. Mice with podocyte-specific deletion of SLK show albuminuria and damage to podocytes as they age. The present study addressed the role of SLK in glomerular injury. We induced adriamycin nephrosis in 3- to 4-mo-old control and podocyte SLK knockout (KO) mice. Compared with control, SLK deletion exacerbated albuminuria and loss of podocytes, synaptopodin, and podocalyxin. Glomeruli of adriamycin-treated SLK KO mice showed diffuse increases in the matrix and sclerosis as well as collapse of the actin cytoskeleton. SLK can phosphorylate ezrin. The complex of phospho-ezrin, Na+/H+ exchanger regulatory factor 2, and podocalyxin in the apical domain of the podocyte is a key determinant of normal podocyte architecture. Deletion of SLK reduced glomerular ezrin and ezrin phosphorylation in adriamycin nephrosis. Also, deletion of SLK reduced the colocalization of ezrin and podocalyxin in the glomerulus. Cultured glomerular epithelial cells with KO of SLK showed reduced ezrin phosphorylation and podocalyxin expression as well as reduced F-actin. Thus, SLK deletion leads to podocyte injury as mice age and exacerbates injury in adriamycin nephrosis. The mechanism may at least in part involve ezrin phosphorylation as well as disruption of the cytoskeleton and podocyte apical membrane structure.


Assuntos
Citoesqueleto de Actina/enzimologia , Doxorrubicina , Glomerulosclerose Segmentar e Focal/enzimologia , Nefrose/enzimologia , Podócitos/enzimologia , Proteínas Serina-Treonina Quinases/deficiência , Citoesqueleto de Actina/patologia , Actinas/metabolismo , Albuminúria/induzido quimicamente , Albuminúria/enzimologia , Albuminúria/genética , Animais , Células Cultivadas , Proteínas do Citoesqueleto/metabolismo , Modelos Animais de Doenças , Técnicas de Silenciamento de Genes , Glomerulosclerose Segmentar e Focal/induzido quimicamente , Glomerulosclerose Segmentar e Focal/genética , Glomerulosclerose Segmentar e Focal/patologia , Camundongos Knockout , Proteínas dos Microfilamentos/metabolismo , Nefrose/induzido quimicamente , Nefrose/genética , Nefrose/patologia , Fosfoproteínas/metabolismo , Fosforilação , Podócitos/patologia , Proteínas Serina-Treonina Quinases/genética , Proteínas/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo
15.
Am J Physiol Renal Physiol ; 318(5): F1295-F1305, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32249614

RESUMO

Podocyte loss and proteinuria are both key features of human diabetic nephropathy (DN). The leptin-deficient BTBR mouse strain with the ob/ob mutation develops progressive weight gain, type 2 diabetes, and diabetic nephropathy that has many features of advanced human DN, including increased mesangial matrix, mesangiolysis, podocyte loss, and proteinuria. Selective antagonism of the endothelin-1 type A receptor (ETAR) by atrasentan treatment in combination with renin-angiotensin-aldosterone system inhibition with losartan has been shown to have the therapeutic benefit of lowering proteinuria in patients with DN, but the underlying mechanism for this benefit is not well understood. Using a similar therapeutic approach in diabetic BTBR ob/ob mice, this treatment regimen significantly increased glomerular podocyte number compared with diabetic BTBR ob/ob controls and suggested that parietal epithelial cells were a source for podocyte restoration. Atrasentan treatment alone also increased podocyte number but to a lesser degree. Mice treated with atrasentan demonstrated a reduction in proteinuria, matching the functional improvement reported in humans. This is a first demonstration that treatment with the highly selective ETAR antagonist atrasentan can lead to restoration of the diminished podocyte number characteristic of DN in humans and thereby underlies the reduction in proteinuria in patients with diabetes undergoing similar treatment. The benefit of ETAR antagonism in DN extended to a decrease in mesangial matrix as measured by a reduction in accumulations of collagen type IV in both the atrasentan and atrasentan + losartan-treated groups compared with untreated controls.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Atrasentana/farmacologia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Nefropatias Diabéticas/prevenção & controle , Antagonistas do Receptor de Endotelina A/farmacologia , Losartan/farmacologia , Podócitos/efeitos dos fármacos , Sistema Renina-Angiotensina/efeitos dos fármacos , Animais , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Quimioterapia Combinada , Feminino , Camundongos , Fosforilação , Podócitos/metabolismo , Podócitos/patologia , Proteinúria/metabolismo , Proteinúria/patologia , Proteinúria/prevenção & controle , Proteínas Quinases S6 Ribossômicas/metabolismo , Serina-Treonina Quinases TOR/metabolismo
16.
Life Sci ; 252: 117653, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32277978

RESUMO

BACKGROUND/AIMS: Rehmanniae Radix (RR) and Cornus officinalis (CO) are a typical herbal pair used to treat diabetic nephropathy (DN) in clinical practice. DN can be effectively treated by catalpol (Cat) and loganin (Log), the main active components of RR and CO respectively, through combating apoptosis, oxidative stress and inflammation. Herein, a spontaneous DN and podocyte injury model induced by advanced glycation end products (AGEs), i.e. KK-Ay mice, was used to explore the cooperative effects of Log and Cat on DN and the mechanism targeting the AGEs-RAGE (receptor for AGE) pathway. METHODS AND KEY FINDINGS: Log and Cat alone or in combination mitigated diabetic symptoms, decreased the level of fasting blood glucose, and increased that of serum insulin. The two drugs alone or in combination protected renal function from damage, prevented extracellular matrix hyperplasia and glycogen deposition, as well as alleviated the loss of podocytes detected by histological assay and immunohistochemistry. Flow cytometry revealed that Log and Cat alone or in combination relieved the apoptosis of AGEs-induced podocytes in vitro. Silencing RAGE by RNA interference played a protective role in podocyte apoptosis, whereas overexpression of it worked oppositely. Western blot exhibited that Log and Cat alone or in combination inhibited the activation of RAGE/p38 MAPK/p65 NF-κB and RAGE/Nox4/p65 NF-κB pathways in podocytes. The inhibitory effects of drug combination were more evident than those of individual treatments. SIGNIFICANCE: Log and Cat cooperatively resisted the apoptosis of podocytes upon DN by targeting AGEs-RAGE and its downstream pathways p38 MAPK and Nox4.


Assuntos
Nefropatias Diabéticas/tratamento farmacológico , Glucosídeos Iridoides/farmacologia , Iridoides/farmacologia , Podócitos/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Nefropatias Diabéticas/patologia , Quimioterapia Combinada , Produtos Finais de Glicação Avançada/metabolismo , Glucosídeos Iridoides/administração & dosagem , Iridoides/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NADPH Oxidase 4/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Podócitos/patologia , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
17.
Am J Kidney Dis ; 75(6): 955-964, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32331832

RESUMO

Podocyte injury is the initiating step in the pathway toward clinically evident forms of nephrotic syndrome known as podocytopathies, represented as either minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS). There are hallmark differences in the histologic appearances of MCD and FSGS, which in turn represent distinct pathogenic models after initial podocyte injury (eg, no change in podocyte number in MCD vs podocyte detachment and death in FSGS). However, MCD and FSGS also share a number of common causes, supporting the theory that these diseases lie along a shared podocytopathy spectrum. In this installment of AJKD's Core Curriculum in Nephrology, we demonstrate how the podocytopathies can be classified according to pathogenesis and treatment response as an alternative to histologic description. Using case examples, we show how these alternative classification schemes can assist not only diagnosis, but also long-term management of podocytopathies.


Assuntos
Glomerulosclerose Segmentar e Focal , Nefrose Lipoide , Síndrome Nefrótica , Podócitos/patologia , Adulto , Gerenciamento Clínico , Glomerulosclerose Segmentar e Focal/etiologia , Glomerulosclerose Segmentar e Focal/patologia , Glomerulosclerose Segmentar e Focal/terapia , Humanos , Nefrose Lipoide/etiologia , Nefrose Lipoide/patologia , Nefrose Lipoide/terapia , Síndrome Nefrótica/etiologia , Síndrome Nefrótica/patologia , Síndrome Nefrótica/terapia
18.
Gene ; 747: 144661, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32275999

RESUMO

Recently, increasing evidence has reported that circRNAs are non-coding RNAs and they bind with the corresponding miRNAs to modulate the target genes. However, the detailed role of circRNAs in the pathogenesis of DN still remains poorly known. Currently, we aimed to study how circ_0000285 functions in DN development. We found that circ_0000285 was significantly increased in DN mice models and mouse podocytes incubated with HG. Then, circ_0000285 was overexpressed in mouse podocytes and we observed that overexpression of circ_0000285 promoted podocytes injury. Moreover, miR-654-3p was precited as a target of circ_0000285. It was shown that circ_0000285 was strongly pulled down by circ_0000285 specific probe and circ_0000285 specific probe was used to successfully enrich miR-654-3p. In addition, we reported that miR-654-3p was obviously down-regulated in DN. Inhibitors of miR-654-3p greatly reversed the effects of circ_0000285 siRNA on podocytes injury. Moreover, the inflammation release was restrained by loss of circ_0000285, while induced by miR-654-3p inhibitors. IL-6, L-1ß and TNF-α level was remarkably depressed by the knockdown of circ_0000285 and miR-654-3p inhibitors induced that. Furthermore, MAPK6 was confirmed as a direct downstream target of miR-654-3p. As shown, MAPK6 was markedly suppressed by circ_0000285 siRNA, which was rescued by the decrease of miR-654-3p. These findings revealed that circ_0000285 promoted podocyte injury via sponging miR-654-3p and activating MAPK6 in DN.


Assuntos
Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , MicroRNAs/metabolismo , Proteína Quinase 6 Ativada por Mitógeno/metabolismo , Podócitos/patologia , RNA Circular/metabolismo , Animais , Sequência de Bases , Citocinas/metabolismo , Progressão da Doença , Regulação da Expressão Gênica , Mediadores da Inflamação/metabolismo , Masculino , Camundongos , MicroRNAs/genética , Proteína Quinase 6 Ativada por Mitógeno/genética , Podócitos/metabolismo , RNA Circular/genética
19.
Sci Rep ; 10(1): 5719, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32235880

RESUMO

Although Heme Oxygenase-1 (HO-1) induction in various forms of kidney injury is protective, its role in age-related renal pathology is unknown. In the ageing kidney there is nephron loss and lesions of focal glomerulosclerosis, interstitial fibrosis, tubular atrophy and arteriolosclerosis. Underlying mechanisms include podocyte (visceral glomerular epithelial cell/GEC) injury. To assess whether HO-1 can attenuate ageing - related lesions, rats with GEC-targeted HO-1 overexpression (GECHO-1 rats) were generated using a Sleeping Beauty (SB) transposon system and extent of lesions over a 12-month period were assessed and compared to those in age-matched wild-type (WT) controls. GECHO-1 rats older than 6 months developed albuminuria that was detectable at 6 months and became significantly higher compared to age-matched WT controls at 12 months. In GECHO-1 rats, lesions of focal segmental and global glomerulosclerosis as well as tubulointerstitial lesions were prominent while podocytes were edematous with areas of foot process effacement and glomerular basement membrane thickening and wrinkling. GECHO-1 rats also developed hemoglobinuria and hemosiderinuria associated with marked tubular hemosiderin deposition and HO-1 induction, while there was depletion of splenic iron stores. Kidney injury was of sufficient magnitude to increase serum lactate dehydrogenase (LDH) and was oxidative in nature as shown by increased expression of 8-hydroxydeoxyguanosine (8-OHdg, a byproduct of oxidative DNA damage) in podocytes and tubular epithelial cells. These observations highlight a detrimental effect of podocyte-targeted HO-1 overexpression on ageing-related renal pathology and point to increased renal iron deposition as a putative underlying mechanism.


Assuntos
Albuminúria/metabolismo , Heme Oxigenase-1/metabolismo , Rim/metabolismo , Podócitos/metabolismo , Envelhecimento/metabolismo , Envelhecimento/patologia , Albuminúria/patologia , Animais , Glomerulosclerose Segmentar e Focal/metabolismo , Glomerulosclerose Segmentar e Focal/patologia , Hemossiderina/metabolismo , Rim/patologia , Podócitos/patologia , Ratos
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