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1.
Int J Mol Sci ; 22(6)2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33802083

RESUMO

Chronic kidney disease (CKD) is a global health problem associated with a number of comorbidities. Recent evidence implicates increased hemichannel-mediated release of adenosine triphosphate (ATP) in the progression of tubulointerstitial fibrosis, the main underlying pathology of CKD. Here, we evaluate the effect of danegaptide on blocking hemichannel-mediated changes in the expression and function of proteins associated with disease progression in tubular epithelial kidney cells. Primary human proximal tubule epithelial cells (hPTECs) were treated with the beta1 isoform of the pro-fibrotic cytokine transforming growth factor (TGFß1) ± danegaptide. qRT-PCR and immunoblotting confirmed mRNA and protein expression, whilst a cytokine antibody array assessed the expression/secretion of proinflammatory and profibrotic cytokines. Carboxyfluorescein dye uptake and ATP biosensing measured hemichannel activity and ATP release, whilst transepithelial electrical resistance was used to assess paracellular permeability. Danegaptide negated carboxyfluorescein dye uptake and ATP release and protected against protein changes associated with tubular injury. Blocking Cx43-mediated ATP release was paralleled by partial restoration of the expression of cell cycle inhibitors, adherens and tight junction proteins and decreased paracellular permeability. Furthermore, danegaptide inhibited TGFß1-induced changes in the expression and secretion of key adipokines, cytokines, chemokines, growth factors and interleukins. The data suggest that as a gap junction modulator and hemichannel blocker, danegaptide has potential in the future treatment of CKD.


Assuntos
Dipeptídeos/farmacologia , Células Epiteliais , Túbulos Renais Proximais , Insuficiência Renal Crônica , Fator de Crescimento Transformador beta1/metabolismo , Linhagem Celular , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Humanos , Túbulos Renais Proximais/lesões , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Insuficiência Renal Crônica/tratamento farmacológico , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/patologia
2.
Int J Mol Sci ; 22(6)2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33802660

RESUMO

Proximal tubular (PT) acidosis, which alkalinizes the urinary filtrate, together with Ca2+ supersaturation in PT can induce luminal calcium phosphate (CaP) crystal formation. While such CaP crystals are known to act as a nidus for CaP/calcium oxalate (CaOx) mixed stone formation, the regulation of PT luminal Ca2+ concentration ([Ca2+]) under elevated pH and/or high [Ca2+] conditions are unknown. Since we found that transient receptor potential canonical 3 (TRPC3) knockout (KO; -/-) mice could produce mild hypercalciuria with CaP urine crystals, we alkalinized the tubular pH in TRPC3-/- mice by oral acetazolamide (0.08%) to develop mixed urinary crystals akin to clinical signs of calcium nephrolithiasis (CaNL). Our ratiometric (λ340/380) intracellular [Ca2+] measurements reveal that such alkalization not only upsurges Ca2+ influx into PT cells, but the mode of Ca2+ entry switches from receptor-operated to store-operated pathway. Electrophysiological experiments show enhanced bicarbonate related current activity in treated PT cells which may determine the stone-forming phenotypes (CaP or CaP/CaOx). Moreover, such alkalization promotes reactive oxygen species generation, and upregulation of calcification, inflammation, fibrosis, and apoptosis in PT cells, which were exacerbated in absence of TRPC3. Altogether, the pH-induced alteration of the Ca2+ signaling signature in PT cells from TRPC3 ablated mice exacerbated the pathophysiology of mixed urinary stone formation, which may aid in uncovering the downstream mechanism of CaNL.


Assuntos
Acetazolamida/farmacologia , Cálcio/metabolismo , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Nefrolitíase/metabolismo , Nefrolitíase/patologia , Animais , Transporte Biológico/efeitos dos fármacos , Calcinose/complicações , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Fibrose , Concentração de Íons de Hidrogênio , Inflamação/patologia , Túbulos Renais Proximais/efeitos dos fármacos , Camundongos , Nefrolitíase/urina , Estresse Oxidativo/efeitos dos fármacos , Canais de Cátion TRPC/metabolismo , Regulação para Cima/efeitos dos fármacos
3.
Ecotoxicol Environ Saf ; 214: 112058, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33714136

RESUMO

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a nuclear transcription factor of great concern which is widely involved in physiological and pathological processes of the organism, but the role and regulatory mechanism of Nrf2 in kidney exposed to cadmium (Cd) remain largely unknown. Here we demonstrated that Cd exposure induced injury in primary rat proximal tubular (rPT) cells and NRK-52E cell line, which was accompanied by autophagic flux blockade and subsequent accumulation of p62. Cd-activated nucleus translocation of Nrf2 depended on p62, which promoted antioxidant genes transcription, but it failed to against Cd-induced cell injury and ultimately succumbed to Cd toxicity. CDDO Methyl Ester (CDDO-ME) or ML385 treatment aggravated or alleviated rPT cells injury induced by Cd respectively, indicating that Nrf2 nucleus translocation played a negative role during Cd-induced rPT cells injury. Phosphorylation of 5' AMP-activated protein kinase (AMPK) decreased together with enhanced Nrf2 nucleus translocation in rPT cells exposed to Cd. Dephosphorylation of AMPK induced by Cd were facilitated or restored by CDDO-ME or ML385 treatment, which confirmed AMPK is a downstream factor of Nrf2. Simultaneously, CDDO-ME further enhanced Phosphorylation of mTOR and AKT which increased during Cd exposure. While, Cd-induced phosphorylation of mTOR and AKT were reversed by ML385 treatment. These results illustrated that Cd mediated Nrf2 nucleus translocation depends on p62 accumulation which results from autophagic flux inhibition. The enhanced nucleus translocation of Nrf2 suppresses phosphorylation of AMPK to inactivate AKT/mTOR signaling, and results in rPT cells injury finally.


Assuntos
Cádmio/toxicidade , Poluentes Ambientais/toxicidade , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Antioxidantes/metabolismo , Autofagia/efeitos dos fármacos , Núcleo Celular/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo
4.
Am J Physiol Regul Integr Comp Physiol ; 320(3): R297-R306, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33407017

RESUMO

Recent evidence indicates a crucial role for G protein-coupled estrogen receptor 1 (GPER1) in the maintenance of cardiovascular and kidney health in females. The current study tested whether GPER1 activation ameliorates hypertension and kidney damage in female Dahl salt-sensitive (SS) rats fed a high-salt (HS) diet. Adult female rats were implanted with telemetry transmitters for monitoring blood pressure and osmotic minipumps releasing G1 (selective GPER1 agonist, 400 µg/kg/day ip) or vehicle. Two weeks after pump implantation, rats were shifted from a normal-salt (NS) diet (0.4% NaCl) to a matched HS diet (4.0% NaCl) for 2 wk. Twenty-four hour urine samples were collected during both diet periods and urinary markers of kidney injury were assessed. Histological assessment of kidney injury was conducted after the 2-wk HS diet period. Compared with values during the NS diet, 24-h mean arterial pressure markedly increased in response to HS, reaching similar values in vehicle-treated and G1-treated rats. HS also significantly increased urinary excretion of protein, albumin, nephrin (podocyte damage marker), and KIM-1 (proximal tubule injury marker) in vehicle-treated rats. Importantly, G1 treatment prevented the HS-induced proteinuria, albuminuria, and increase in KIM-1 excretion but not nephrinuria. Histological analysis revealed that HS-induced glomerular damage did not differ between groups. However, G1 treatment preserved proximal tubule brush-border integrity in HS-fed rats. Collectively, our data suggest that GPER1 activation protects against HS-induced proteinuria and albuminuria in female Dahl SS rats by preserving proximal tubule brush-border integrity in a blood pressure-independent manner.


Assuntos
Albuminúria/prevenção & controle , Ciclopentanos/farmacologia , Nefropatias/prevenção & controle , Glomérulos Renais/efeitos dos fármacos , Túbulos Renais Proximais/efeitos dos fármacos , Quinolinas/farmacologia , Receptores Acoplados a Proteínas-G/agonistas , Albuminúria/etiologia , Albuminúria/metabolismo , Albuminúria/patologia , Animais , Pressão Arterial , Moléculas de Adesão Celular/metabolismo , Modelos Animais de Doenças , Feminino , Hipertensão/etiologia , Hipertensão/fisiopatologia , Nefropatias/etiologia , Nefropatias/metabolismo , Nefropatias/patologia , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Ratos Endogâmicos Dahl , Receptores Acoplados a Proteínas-G/metabolismo , Transdução de Sinais , Cloreto de Sódio na Dieta
5.
Am J Physiol Renal Physiol ; 320(3): F359-F374, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33427061

RESUMO

Lysophosphatidic acid (LPA) increases platelet-derived growth factor-B (PDGFB) and connective tissue growth factor (CTGF) production and secretion by proximal tubule (PT) cells through LPA2 receptor-Gqα-αvß6-integrin-mediated activation of transforming growth factor-ß1 (TGFB1). LPA2, ß6-integrin, PDGFB, and CTGF increase in kidneys after ischemia-reperfusion injury (IRI), coinciding with fibrosis. The TGFB1 receptor antagonist SD-208 prevents increases of ß6-integrin, TGFB1-SMAD signaling, and PDGFB/CTGF expression after IRI and ameliorates fibrosis (Geng H, Lan R, Singha PK, Gilchrist A, Weinreb PH, Violette SM, Weinberg JM, Saikumar P, Venkatachalam MA. Am J Pathol 181: 1236-1249, 2012; Geng H, Lan R, Wang G, Siddiqi AR, Naski MC, Brooks AI, Barnes JL, Saikumar P, Weinberg JM, Venkatachalam MA. Am J Pathol 174: 1291-1308, 2009). We report now that LPA1 receptor signaling through epidermal growth factor receptor (EGFR)-ERK1/2-activator protein-1 cooperates with LPA2-dependent TGFB1 signaling to additively increase PDGFB/CTGF production and secretion by PT cells. Conversely, inhibition of both pathways results in greater suppression of PDGFB/CTGF production and secretion and promotes greater PT cellular differentiation than inhibiting one pathway alone. Antagonism of the LPA-generating enzyme autotaxin suppressed signaling through both pathways. After IRI, kidneys showed not only more LPA2, nuclear SMAD2/3, and PDGFB/CTGF but also increased LPA1 and autotaxin proteins, together with enhanced EGFR/ERK1/2 activation. Remarkably, the TGFB1 receptor antagonist SD-208 prevented all of these abnormalities excepting increased LPA2. SD-208 inhibits only one arm of LPA signaling: LPA2-Gqα-αvß6-integrin-dependent production of active TGFB1 and its receptor-bound downstream effects. Consequently, far-reaching protection by SD-208 against IRI-induced signaling alterations and tubule-interstitial pathology is not fully explained by our data. TGFB1-dependent feedforward modulation of LPA1 signaling is one possibility. SD-208 effects may also involve mitigation of injury caused by IRI-induced TGFB1 signaling in endothelial cells and monocytes. Our results have translational implications for using TGFB1 receptor antagonists, LPA1 and LPA2 inhibitors concurrently, and autotaxin inhibitors in acute kidney injury to prevent the development of chronic kidney disease.


Assuntos
Lesão Renal Aguda/metabolismo , Citocinas/metabolismo , Túbulos Renais Proximais/metabolismo , Receptores de Ácidos Lisofosfatídicos/metabolismo , Traumatismo por Reperfusão/metabolismo , Lesão Renal Aguda/genética , Lesão Renal Aguda/patologia , Animais , Linhagem Celular , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Modelos Animais de Doenças , Receptores ErbB/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fibrose , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Túbulos Renais Proximais/patologia , Linfocinas/metabolismo , Masculino , Camundongos , Fosforilação , Fator de Crescimento Derivado de Plaquetas/metabolismo , Ratos Sprague-Dawley , Receptores de Ácidos Lisofosfatídicos/genética , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/patologia , Transdução de Sinais , Fator de Transcrição AP-1/metabolismo , Fator de Crescimento Transformador beta1/metabolismo
6.
Life Sci ; 266: 118879, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33310030

RESUMO

Acute renal injury (AKI) is a risk factor for the development of hypertension, which involves oxidative stress, changes in Na+ handling, and the intrarenal renin-angiotensin-aldosterone system (RAAS) as underlying mechanisms. We investigated in rats whether renal ischemia-reperfusion (IR) leads to changes in the proximal tubule ATP-dependent Na+ transport and the intrarenal content of RAAS components, as well as the role of NADPH oxidase. Rats weighing 300-350 g were submitted to AKI by bilateral IR (n = 25). After IR injury, the animals were followed up for 4 weeks. One part (n = 7) received daily treatment with the NADPH oxidase inhibitor apocynin (100 mg/kg, drinking water), while another part (n = 9) received apocynin 24 h before and after IR. One group was submitted to sham surgery (n = 8). Four weeks after IR, the rats presented elevated systolic blood pressure, as well as increased lipid peroxidation, NADPH oxidase activity, (Na++K+)ATPase activity, and upregulation of type 1 angiotensin II receptor in the renal cortex. On the other hand, there was a decrease in Na+-ATPase activity and downregulation of the isoforms 1 and 2 of the angiotensin-converting enzyme, type 2 angiotensin II receptor, and of the α and ε isoforms of protein kinase C. Most of these alterations was prevented by both apocynin treatment protocols. Thus, we conclude that AKI-induced by IR may induce changes in proximal tubule ATPases and RAAS components compatible with renal Na+ retention and hypertension. These data also indicate that the NADPH oxidase represents a key factor in the origin of these alterations.


Assuntos
Lesão Renal Aguda/complicações , Hipertensão/patologia , Túbulos Renais Proximais/patologia , NADPH Oxidases/metabolismo , Sistema Renina-Angiotensina , Traumatismo por Reperfusão/complicações , Sódio/metabolismo , Lesão Renal Aguda/metabolismo , Lesão Renal Aguda/patologia , Aldosterona/metabolismo , Animais , Hipertensão/enzimologia , Hipertensão/etiologia , Túbulos Renais Proximais/metabolismo , Masculino , Estresse Oxidativo , Ratos , Ratos Wistar , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia
7.
Molecules ; 26(1)2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33374869

RESUMO

Twelve compounds, including two new aristolochic acid analogues with a formyloxy moiety (9-10) and 10 known aristolochic acid derivates (1-8 and 11-12), were obtained from the roots of Aristolochiacontorta. Their structures were elucidated using extensive spectroscopic methods. Their cytotoxic activity in human proximal tubular cells HK-2 was evaluated by the MTT method, which has been widely used to assess cell viability. Among these molecules, compounds 3 and 9 were found to be more cytotoxic. Furthermore, molecular modeling was used to evaluate, for the first time, the interactions of compounds 3 and 9 with the target protein organic anionic transporter 1 (OAT1) that plays a key role in mediating aristolochic acid nephropathy. Structure-activity relationships are briefly discussed.


Assuntos
Aristolochia/química , Ácidos Aristolóquicos/farmacologia , Carcinógenos/farmacologia , Citotoxinas/farmacologia , Túbulos Renais Proximais/patologia , Raízes de Plantas/química , Proliferação de Células , Células Cultivadas , Humanos , Túbulos Renais Proximais/efeitos dos fármacos
8.
Cell Prolif ; 53(11): e12909, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32975326

RESUMO

OBJECTIVES: In diabetic nephropathy (DN), hypoxia-inducible factor-1α (HIF-1α) activation in tubular cells plays an important protective role against kidney injury. The effects may occur via the target genes of HIF-1α, such as haem oxygenase-1 (HO-1), but the exact mechanisms are incompletely understood. MATERIALS AND METHODS: Mice with proximal tubule-specific knockout of HIF-1α (PT-HIF-1α-/- mice) were generated, and diabetes was induced in these mice by streptozotocin (STZ) injection. In addition, to mimic a hypoxic state, cobaltous chloride (CoCl2 ) was applied to HK-2 cells. RESULTS: Our study first verified that conditional knockout of HIF-1α worsened tubular injury in DN; additionally, aggravated kidney dysfunction, renal histopathological alterations, mitochondrial fragmentation, ROS accumulation and apoptosis were observed in diabetic PT-HIF-1α-/- mice. In vitro study showed that compared to control group, HK-2 cells cultured under hypoxic ambiance displayed increased mitochondrial fragmentation, ROS production, mitochondrial membrane potential loss and apoptosis. These increases were reversed by overexpression of HIF-1α or treatment with a HO-1 agonist. Importantly, cotreatment with a HIF-1α inhibitor and a HO-1 agonist rescued the HK-2 cells from the negative impacts of the HIF-1α inhibitor. CONCLUSIONS: These data revealed that HIF-1α exerted a protective effect against tubular injury in DN, which could be mediated via modulation of mitochondrial dynamics through HO-1 upregulation.


Assuntos
Nefropatias Diabéticas/patologia , Heme Oxigenase-1/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Túbulos Renais Proximais/patologia , Dinâmica Mitocondrial , Animais , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/metabolismo , Deleção de Genes , Técnicas de Inativação de Genes , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Túbulos Renais Proximais/metabolismo , Masculino , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia
9.
Chem Biol Interact ; 330: 109251, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32888910

RESUMO

Cisplatin induces acute renal failure in humans and mice.Tubular apoptosis, necrosis and inflammation are the primary pathogenesis of cisplatin-induced acute kidney injury(AKI). We previously reported that the depletion of Numb from proximal tubules exacerbates tubular cells apoptosis in cisplatin-induced AKI, however, the role of Numb in tubular necrosis and renal inflammation in cisplatin-induced AKI remains unclear. A mouse model of AKI was produced by cisplatin intraperitoneally injection in mice from proximal tubule-specific depletion of Numb (PT-Nb-KO) and their wild-type littermates (PT-Nb-WT) respectively. Renal Numb expression was determined by Western blotting. Renal morphological damage was examined by hematoxylin and eosin staining (H&E staining). Tubular necrosis was evaluated by histological study and the protein level of renal Mixed lineage kinase domain-like protein (MLKL) which is a molecular marker of necrosis. Leukocyte infiltration and pro-inflammatory cytokines was determined by immunostaining and quantitative real-time PCR (qRT-PCR) respectively.The protein level of Numb was dramatically decreased in kidneys of PT-Nb-KO mice compared with PT-Nb-WT mice. After cisplatin injection, a significant increase of tubular injury score and the protein level of renal MLKL were detected in PT-Nb-KO mice compared with those in PT-Nb-WT. In addition, the number of F4/80-positve and CD3-positive cells, markers for macrophages and neutraphils respectively, showed significantly increased in kidneys from PT-Nb-KO mice compared with those in PT-Nb-WT mice. Consistently, the gene expression of pro-inflammatory cytokines including TNF-α and MCP-1 in the kidneys was higher in PT-Nb-KO mice than those in PT-Nb-WT mice. Numb play additional protective role in cisplatin-induced AKI through ameliorating tubular necrosis and renal inflammation besides attenuating cisplatin-induced tubular apoptosis.


Assuntos
Lesão Renal Aguda/patologia , Cisplatino/efeitos adversos , Inflamação/prevenção & controle , Proteínas de Membrana/fisiologia , Necrose/prevenção & controle , Proteínas do Tecido Nervoso/fisiologia , Animais , Contagem de Células , Citocinas/metabolismo , Modelos Animais de Doenças , Inflamação/etiologia , Túbulos Renais Proximais/patologia , Mastócitos , Proteínas de Membrana/deficiência , Camundongos , Camundongos Knockout , Necrose/etiologia , Proteínas do Tecido Nervoso/deficiência , Neutrófilos , Proteínas Quinases/metabolismo
10.
Am J Physiol Renal Physiol ; 319(4): F697-F711, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32865013

RESUMO

Praliciguat, a clinical-stage soluble guanylate cyclase (sGC) stimulator, increases cGMP via the nitric oxide-sGC pathway. Praliciguat has been shown to be renoprotective in rodent models of hypertensive nephropathy and renal fibrosis. In the present study, praliciguat alone and in combination with enalapril attenuated proteinuria in the obese ZSF1 rat model of diabetic nephropathy. Praliciguat monotherapy did not affect hemodynamics. In contrast, enalapril monotherapy lowered blood pressure but did not attenuate proteinuria. Renal expression of genes in pathways involved in inflammation, fibrosis, oxidative stress, and kidney injury was lower in praliciguat-treated obese ZSF1 rats than in obese control rats; fasting glucose and cholesterol were also lower with praliciguat treatment. To gain insight into how tubular mechanisms might contribute to its pharmacological effects on the kidneys, we studied the effects of praliciguat on pathological processes and signaling pathways in cultured human primary renal proximal tubular epithelial cells (RPTCs). Praliciguat inhibited the expression of proinflammatory cytokines and secretion of monocyte chemoattractant protein-1 in tumor necrosis factor-α-challenged RPTCs. Praliciguat treatment also attenuated transforming growth factor-ß-mediated apoptosis, changes to a mesenchyme-like cellular phenotype, and phosphorylation of SMAD3 in RPTCs. In conclusion, praliciguat improved proteinuria in the ZSF1 rat model of diabetic nephropathy, and its actions in human RPTCs suggest that tubular effects may contribute to its renal benefits, building upon strong evidence for the role of cGMP signaling in renal health.


Assuntos
Apoptose/efeitos dos fármacos , Nefropatias Diabéticas/tratamento farmacológico , Agonistas da Guanilil Ciclase C/farmacologia , Túbulos Renais Proximais/efeitos dos fármacos , Nefrite/tratamento farmacológico , Pirazóis/farmacologia , Pirimidinas/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , Linhagem Celular , Citocinas/metabolismo , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Progressão da Doença , Enalapril/farmacologia , Humanos , Mediadores da Inflamação/metabolismo , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Masculino , Nefrite/metabolismo , Nefrite/patologia , Fosforilação , Ratos Zucker , Transdução de Sinais , Proteína Smad3/metabolismo
11.
Am J Physiol Renal Physiol ; 319(4): F579-F591, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32799673

RESUMO

Tubular atrophy is a common pathological feature of kidney fibrosis. Although fibroblasts play a predominant role in tissue fibrosis, the role of repairing tubular epithelia in tubular atrophy is unclear. We demonstrated the essential role of focal adhesion kinase (FAK)-mediated intratubular epithelial-mesenchymal transition (EMT) in the pathogenesis of tubular atrophy after severe ischemia-reperfusion injury (IRI). Actively proliferating tubular epithelia undergoing intratubular EMT were noted in the acute phase of severe IRI, resulting in tubular atrophy in the chronic phase, reflecting failed tubular repair. Furthermore, FAK was phosphorylated in the tubular epithelia in the acute phase of severe IRI, and its inhibition ameliorated both tubular atrophy and interstitial fibrosis in the chronic phase after injury. In vivo clonal analysis of single-labeled proximal tubular epithelial cells after IRI using proximal tubule reporter mice revealed substantial clonal expansion after IRI, reflecting active epithelial proliferation during repair. The majority of these proliferating epithelia were located in atrophic and nonfunctional tubules, and FAK inhibition was sufficient to prevent tubular atrophy. In vitro, transforming growth factor-ß induced FAK phosphorylation and an EMT phenotype, which was also prevented by FAK inhibition. In an in vitro tubular epithelia gel contraction assay, transforming growth factor-ß treatment accelerated gel contraction, which was suppressed by FAK inhibition. In conclusion, injury-induced intratubular EMT is closely related to tubular atrophy in a FAK-dependent manner.


Assuntos
Lesão Renal Aguda/patologia , Células Epiteliais/patologia , Transição Epitelial-Mesenquimal , Túbulos Renais Proximais/patologia , Lesão Renal Aguda/tratamento farmacológico , Lesão Renal Aguda/metabolismo , Animais , Atrofia , Linhagem Celular , Proliferação de Células , Modelos Animais de Doenças , Inibidores Enzimáticos/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Fibrose , Quinase 1 de Adesão Focal/antagonistas & inibidores , Quinase 1 de Adesão Focal/metabolismo , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Masculino , Camundongos Transgênicos , Fenótipo , Fosforilação , Ratos , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIa/genética , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIa/metabolismo
12.
Am J Physiol Renal Physiol ; 319(4): F686-F696, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32830535

RESUMO

Renal proximal tubular apoptosis plays a critical role in kidney health and disease. However, cellular molecules that trigger renal apoptosis remain elusive. Here, we evaluated the effect of inhibiting protein disulfide isomerase (PDI), a critical thioredoxin chaperone protein, on apoptosis as well as the underlying mechanisms in human renal proximal tubular (HK2) cells. HK2 cells were transfected with PDI-specific siRNA in the absence and presence of an antioxidant, tempol. PDI siRNA transfection resulted in a decrease of ~70% in PDI protein expression and enzyme activity. PDI inhibition increased caspase-3 activity and induced profound cell apoptosis. Mitochondrial function, as assessed by mitochondrial cytochrome c levels, mitochondrial membrane potential, oxygen consumption, and ATP levels, was significantly reduced in PDI-inhibited cells. Also, PDI inhibition caused nuclear factor erythroid 2-related factor 2 (Nrf2; a redox-sensitive transcription factor) cytoplasmic sequestration, decreased superoxide dismutase and glutathione-S-transferase activities, and increased oxidative stress. In PDI-inhibited cells, tempol reduced apoptosis, caspase-3 activity, and oxidative stress and also restored Nrf2 nuclear translocation and mitochondrial function. Silencing Nrf2 in the cells abrogated the beneficial effect of tempol, whereas Kelch-like ECH-associated protein 1 (an Nrf2 regulatory protein) silencing protected cells from PDI inhibitory effects. Collectively, our data indicate that PDI inhibition diminishes Nrf2 nuclear translocation, causing oxidative stress that further triggers mitochondrial dysfunction and renal cell apoptosis. This study suggests an important role for PDI in renal cell apoptosis involving Nrf2 and mitochondrial dysfunction.


Assuntos
Apoptose , Células Epiteliais/enzimologia , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Túbulos Renais Proximais/enzimologia , Mitocôndrias/enzimologia , Fator 2 Relacionado a NF-E2/metabolismo , Isomerases de Dissulfetos de Proteínas/metabolismo , Transporte Ativo do Núcleo Celular , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular , Óxidos N-Cíclicos/farmacologia , Metabolismo Energético , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/patologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/patologia , Fator 2 Relacionado a NF-E2/genética , Estresse Oxidativo , Isomerases de Dissulfetos de Proteínas/genética , Interferência de RNA , Transdução de Sinais , Marcadores de Spin
13.
Am J Physiol Renal Physiol ; 319(4): F603-F611, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32830538

RESUMO

The acyl-CoA synthetase medium-chain family member 2 (Acsm2) gene was first identified and cloned by our group as a kidney-specific "KS" gene. However, its expression pattern and function remain to be clarified. In the present study, we found that the Acsm2 gene was expressed specifically and at a high level in normal adult kidneys. Expression of Acsm2 in kidneys followed a maturational pattern: it was low in newborn mice and increased with kidney development and maturation. In situ hybridization and immunohistochemistry revealed that Acsm2 was expressed specifically in proximal tubular cells of adult kidneys. Data from the Encyclopedia of DNA Elements database revealed that the Acsm2 gene locus in the mouse has specific histone modifications related to the active transcription of the gene exclusively in kidney cells. Following acute kidney injury, partial unilateral ureteral obstruction, and chronic kidney diseases, expression of Acsm2 in the proximal tubules was significantly decreased. In human samples, the expression pattern of ACSM2A, a homolog of mouse Acsm2, was similar to that in mice, and its expression decreased with several types of renal injuries. These results indicate that the expression of Acsm2 parallels the structural and functional maturation of proximal tubular cells. Downregulation of its expression in several models of kidney disease suggests that Acms2 may serve as a novel marker of proximal tubular injury and/or dysfunction.


Assuntos
Coenzima A Ligases/metabolismo , Células Epiteliais/metabolismo , Túbulos Renais Proximais/metabolismo , Lesão Renal Aguda/enzimologia , Lesão Renal Aguda/genética , Lesão Renal Aguda/patologia , Animais , Coenzima A Ligases/genética , Modelos Animais de Doenças , Células Epiteliais/patologia , Fibrose , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Humanos , Integrina beta1/genética , Integrina beta1/metabolismo , Túbulos Renais Proximais/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Insuficiência Renal Crônica/enzimologia , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/patologia , Renina/genética , Renina/metabolismo , Traumatismo por Reperfusão/enzimologia , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/patologia
14.
Life Sci ; 261: 118347, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32853650

RESUMO

The effect of exosomes on receptor cells participating in intercellular communication has been extensively studied, but the effect of exosomes on donor cells remains unclear. It has been reported that exosomes secreted by renal proximal tubular epithelial cells (PTECs) under different stimuli accelerate acute and chronic kidney diseases. This study aimed to explore whether inhibiting exosomal secretion in PTECs by knocking out Rab27a, a key exosome regulatory gene, inhibits the excessive inflammatory response in PTECs and delays diabetic kidney disease (DKD). First, we proved that the bovine serum albumin (BSA)-induced inflammatory response in HK-2 cells was inhibited by knocking out Rab27a and that Rab27a, IL-6, TNF-α and COL-1 expression was markedly increased in an HFD/STZ-induced diabetic mouse model. Furthermore, miR-26a-5p expression in exosomes secreted by BSA-treated HK-2 cells was significantly increased but correspondingly decreased in the cells; after knocking out Rab27a, miR-26a-5p levels in the cells rebounded. Next, we confirmed that a miR-26a-5p mimic suppressed the inflammatory response, while a miR-26a-5p inhibitor accelerated the inflammatory response. Then, we found that miR-26a-5p targets the 3'-untranslated region (UTR) of CHAC1. Furthermore, the inflammatory response and NF-κB signalling pathway activation induction by the miR-26a-5p inhibitor were abolished by CHAC1 knockout. Therefore, we conclude that inhibiting exosome secretion by BSA-induced PTECs promotes miR-26a-5p expression in cells, thereby inhibiting the CHAC1/NF-κB pathways to prevent the inflammatory response in PTECs and delaying the development of DKD. This study provides new insight into the pathogenic mechanism of exosomes and a new therapeutic target for DKD.


Assuntos
Diabetes Mellitus Experimental/fisiopatologia , Nefropatias Diabéticas/fisiopatologia , MicroRNAs/genética , Proteínas rab27 de Ligação ao GTP/genética , Animais , Linhagem Celular , Diabetes Mellitus Experimental/genética , Nefropatias Diabéticas/genética , Células Epiteliais/citologia , Exossomos/metabolismo , Técnicas de Inativação de Genes , Humanos , Inflamação/genética , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Soroalbumina Bovina , gama-Glutamilciclotransferase/metabolismo
15.
Am J Physiol Renal Physiol ; 319(4): F664-F673, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32715764

RESUMO

Tubular changes contribute to the development of renal pathologies in diabetic kidney disease (DKD), including interstitial fibrosis. It is unclear how tubular cells relay signals to interstitial fibroblasts. Recently, exosomes have been recognized as crucial mediators of intercellular communication. We hypothesized that exosomes secreted from tubular cells may stimulate fibroblasts for interstitial fibrosis in DKD. In this study, we isolated and purified exosomes from the renal cortex of DKD mice and high glucose-treated mouse proximal tubular cells. Compared with nondiabetic mice, exosome secretion in kidney tissues decreased in DKD mice. Likewise, high glucose incubation reduced exosome secretion in mouse kidney proximal tubular BUMPT cells. To study the effect of tubular cell exosomes on fibroblasts, exosomes from BUMPT cells were added to renal fibroblast NRK-49F cell cultures. Notably, exosomes from high glucose conditioned BUMPT cells induced higher proliferation, significant morphological change, and substantial production of fibronectin, α-smooth muscle actin, and collagen type Ι in NRK-49F fibroblasts. Proteomics analysis was further performed to profile the proteins within tubular cell exosomes. Interestingly, 22 proteins were found to be differentially expressed between tubular exosomes derived from high glucose conditioned cells and those from normal glucose conditioned cells. Cytoscape analysis suggested the existence of two protein-protein interaction networks in these exosomal differentially expressed proteins. While one of the protein-protein interaction networks comprised enolase 1 (Eno1), heat shock protein family A member 8 (Hspa8), thioredoxin 1 (Txn1), peptidylprolyl isomerase A (Ppia), phosphoglycerate kinase 1 (Pgk1), DNA topoisomerase II-ß (Top2b), and ß-actin (Actb), the other had the family proteins of human leucocyte antigen F (Ywhag), a component of the ND10 nuclear body (Ywhae), interferon regulatory factor-8 (Ywhaq), and human leucocyte antigen A (Ywhaz). Gene expression analysis via Nephroseq showed a correlation of Eno1 expression with DKD clinical manifestation. In conclusion, DKD is associated with a decrease in exosome secretion in renal tubular cells. Exosomes from high glucose conditioned tubular cells may regulate the proliferation and activation of fibroblasts, contributing to the paracrine signaling mechanism responsible for the pathological onset of renal interstitial fibrosis in DKD.


Assuntos
Proliferação de Células , Nefropatias Diabéticas/metabolismo , Exossomos/metabolismo , Fibroblastos/metabolismo , Túbulos Renais Proximais/metabolismo , Comunicação Parácrina , Animais , Linhagem Celular , Técnicas de Cocultura , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Modelos Animais de Doenças , Progressão da Doença , Exossomos/genética , Exossomos/patologia , Fibroblastos/patologia , Fibrose , Túbulos Renais Proximais/patologia , Masculino , Camundongos Endogâmicos C57BL , Fosfopiruvato Hidratase/metabolismo , Mapas de Interação de Proteínas , Via Secretória , Transdução de Sinais
16.
Adv Exp Med Biol ; 1207: 469-480, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32671769

RESUMO

Acute kidney injury (AKI) is one of the major kidney diseases associated with poor clinical outcomes both in short- and long-term, which caused by toxins, transient ischemia, and so on. Autophagy is a cellular stress response that plays important roles in the pathogenesis of various diseases, including kidney diseases. Autophagy is induced in proximal tubules during AKI. It has been demonstrated that autophagy plays a renoprotective role in AKI by pharmacological and genetic inhibitory studies. However, the role of autophagy in kidney recovery and repair from AKI remains unknown mostly. In many studies, a dynamic change of autophagy was important for tubular proliferation and repair in the recovery phase of AKI. Moreover, autophagy may not only promote renal fibrosis through inducing tubular atrophy and decomposition but also prevent it by mediating intracellular degradation of excessive collagen in terms of renal fibrosis. In further researches, we expect to clarify the regulation of autophagy in kidney injury and repair, and find out therapeutic drugs for treating AKI and preventing its progression to chronic kidney disease.


Assuntos
Lesão Renal Aguda , Autofagia , Lesão Renal Aguda/tratamento farmacológico , Lesão Renal Aguda/patologia , Humanos , Túbulos Renais Proximais/patologia , Insuficiência Renal Crônica/patologia , Insuficiência Renal Crônica/prevenção & controle
17.
Life Sci ; 257: 118116, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32702447

RESUMO

Emerging evidence implicates accelerated renal tubular epithelial cell (RTEC) senescence in renal fibrosis progression. Mitophagy protects against kidney injury. However, the mechanistic interplay between cell senescence and mitophagy in RTECs is not clearly defined. The purpose of this study was to evaluate the inhibition of RTEC senescence and renal fibrosis by quercetin and explore the underlying mechanisms. We found that quercetin attenuated RTEC senescence induced by angiotensin II (AngII) in vitro and unilateral ureteral obstruction in vivo. Moreover, we demonstrated that mitochondrial abnormalities such as elevated reactive oxygen species, decreased membrane potential, and fragmentation and accumulation of mitochondrial mass, occurred in AngII-treated RTECs. Quercetin treatment reversed these effects. Furthermore, quercetin enhanced mitophagy in AngII-treated RTECs, which was markedly reduced by treatment with mitophagy-specific inhibitors. Sirtuin-1 (SIRT1) was involved in quercetin-mediated PTEN-induced kinase 1 (PINK1)/Parkin-associated mitophagy activation. Pharmacological antagonism of SIRT1 in AngII-treated RTECs blocked the effects of quercetin on mitophagy and cellular senescence. Finally, quercetin alleviated kidney fibrosis by reducing RTEC senescence via mitophagy. Collectively, the antifibrotic effect of quercetin involved inhibition of RTEC senescence, possibly through activation of SIRT1/PINK1/Parkin-mediated mitophagy. These findings suggest that pharmacological elimination of senescent cells and stimulation of mitophagy represent effective therapeutic strategies to prevent kidney fibrosis.


Assuntos
Antioxidantes/farmacologia , Senescência Celular/efeitos dos fármacos , Túbulos Renais Proximais/efeitos dos fármacos , Rim/patologia , Mitofagia/efeitos dos fármacos , Proteínas Quinases/metabolismo , Quercetina/farmacologia , Sirtuína 1/metabolismo , Animais , Antioxidantes/uso terapêutico , Linhagem Celular , Epitélio/efeitos dos fármacos , Fibrose , Citometria de Fluxo , Rim/efeitos dos fármacos , Túbulos Renais Proximais/patologia , Quercetina/uso terapêutico , Ratos
18.
Clin Sci (Lond) ; 134(12): 1357-1376, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32490513

RESUMO

Non-specific inhibition of Rho-associated kinases (ROCKs) alleviated renal fibrosis in the unilateral ureteral obstruction (UUO) model, while genetic deletion of ROCK1 did not affect renal pathology in mice. Thus, whether ROCK2 plays a role in renal tubulointerstitial fibrosis needs to be clarified. In the present study, a selective inhibitor against ROCK2 or genetic approach was used to investigate the role of ROCK2 in renal tubulointerstitial fibrosis. In the fibrotic kidneys of chronic kidney diseases (CKDs) patients, we observed an enhanced expression of ROCK2 with a positive correlation with interstitial fibrosis. In mice, the ROCK2 protein level was time-dependently increased in the UUO model. By treating CKD animals with KD025 at the dosage of 50 mg/kg/day via intraperitoneal injection, the renal fibrosis shown by Masson's trichrome staining was significantly alleviated along with the reduced expression of fibrotic genes. In vitro, inhibiting ROCK2 by KD025 or ROCK2 knockdown/knockout significantly blunted the pro-fibrotic response in transforming growth factor-ß1 (TGF-ß1)-stimulated mouse renal proximal tubular epithelial cells (mPTCs). Moreover, impaired cellular metabolism was reported as a crucial pathogenic factor in CKD. By metabolomics analysis, we found that KD025 restored the metabolic disturbance, including the impaired glutathione metabolism in TGF-ß1-stimulated tubular epithelial cells. Consistently, KD025 increased antioxidative stress enzymes and nuclear erythroid 2-related factor 2 (Nrf2) in fibrotic models. In addition, KD025 decreased the infiltration of macrophages and inflammatory response in fibrotic kidneys and blunted the activation of macrophages in vitro. In conclusion, inhibition of ROCK2 may serve as a potential novel therapy for renal tubulointerstitial fibrosis in CKD.


Assuntos
Células Epiteliais/enzimologia , Túbulos Renais Proximais/patologia , Doenças Metabólicas/enzimologia , Quinases Associadas a rho/antagonistas & inibidores , Adolescente , Animais , Anti-Inflamatórios/farmacologia , Criança , Pré-Escolar , Modelos Animais de Doenças , Células Epiteliais/efeitos dos fármacos , Feminino , Fibrose , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Lactente , Inflamação/patologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Doenças Metabólicas/patologia , Camundongos , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Células RAW 264.7 , Proteína Smad2/metabolismo , Fator de Crescimento Transformador beta1/farmacologia , Regulação para Cima/efeitos dos fármacos , Obstrução Ureteral/enzimologia , Obstrução Ureteral/patologia , Quinases Associadas a rho/metabolismo
19.
Proc Natl Acad Sci U S A ; 117(27): 15874-15883, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32571916

RESUMO

After acute kidney injury (AKI), patients either recover or alternatively develop fibrosis and chronic kidney disease. Interactions between injured epithelia, stroma, and inflammatory cells determine whether kidneys repair or undergo fibrosis, but the molecular events that drive these processes are poorly understood. Here, we use single nucleus RNA sequencing of a mouse model of AKI to characterize cell states during repair from acute injury. We identify a distinct proinflammatory and profibrotic proximal tubule cell state that fails to repair. Deconvolution of bulk RNA-seq datasets indicates that this failed-repair proximal tubule cell (FR-PTC) state can be detected in other models of kidney injury, increasing during aging in rat kidney and over time in human kidney allografts. We also describe dynamic intercellular communication networks and discern transcriptional pathways driving successful vs. failed repair. Our study provides a detailed description of cellular responses after injury and suggests that the FR-PTC state may represent a therapeutic target to improve repair.


Assuntos
Lesão Renal Aguda/metabolismo , Túbulos Renais Proximais/metabolismo , Rim/metabolismo , Transcriptoma , Lesão Renal Aguda/genética , Lesão Renal Aguda/patologia , Aloenxertos , Animais , Modelos Animais de Doenças , Fibrose , Redes Reguladoras de Genes , Humanos , Rim/lesões , Túbulos Renais Proximais/lesões , Túbulos Renais Proximais/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Análise de Sequência de RNA , Células Estromais/metabolismo , Células Estromais/patologia
20.
Life Sci ; 254: 117742, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32360619

RESUMO

AIMS: Baicalin, a flavonoid glycoside substance extracted from Scutellaria baicalensis Georgi, has been shown to exhibit multiple therapeutic properties owing to its anti-inflammatory effect. Diabetes is characterized by chronic hyperglycemia, inflammation and oxidative stress, which promote renal fibrosis and kidney failure. Although anti-fibrogenic effects of baicalin in lung and liver have been reported previously, no study has investigated its roles in renal fibrosis. Here, we demonstrated protective effects of baicalin against fibrogenic process in human kidney proximal tubular epithelial cells (HK-2) exposed to diabetic milieu. MAIN METHODS: To investigate the effects of baicalin on oxidative stress- and inflammation-induced fibrosis in HK-2 cells, protein and gene expressions of NF-κB- and STAT3-associated inflammatory molecules and TGFß-associated extracellular matrix proteins were examined by western blotting, immunocytochemistry and qRT-PCR. To determine physiological changes of HK-2 exposed to diabetic milieu in response to baicalin, production of cAMP and cGMP and Ca2+ influx were measured. KEY FINDINGS: Baicalin attenuated oxidative stress- and inflammation-inudced IκB and JAK2 phosphorylations and, subsequent, NF-κB nuclear translocation and STAT3 phosphorylation. Consequently, it markedly reduced transactivation of NF-κB- and STAT3-associated inflammatory genes such as ICAM1, VCAM1, TGFß, IL1ß and MCP1, and protein expression of TGFß-associated extracellular matrix proteins, such as fibronectin and collagen IV. These effects are, partially, attributed to its regulatory function of intracellular concentration of Ca2+ via interaction with type A γ-aminobutyric acid receptor. SIGNIFICANCE: This is the first study which investigated anti-fibrogenic effect of baicalin in human kidney cells, and our results highlight a potential therapeutic application of baicalin for diabetic nephropathy.


Assuntos
Diabetes Mellitus Tipo 2/patologia , Flavonoides/farmacologia , Túbulos Renais Proximais/efeitos dos fármacos , Adulto , Linhagem Celular , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Expressão Gênica , Humanos , Inflamação/metabolismo , Túbulos Renais Proximais/patologia , Masculino , Proteínas/metabolismo
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