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1.
Cells ; 11(24)2022 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-36552750

RESUMO

Although recent studies have reported that long non-coding RNA (lncRNA) is involved in the development of ischemic acute kidney injury (AKI), the exact function and regulatory mechanism of lncRNAs in ischemic AKI remain largely unknown. Herein, we found that ischemic injury promoted the expression of lncRNA 148400 in mouse proximal tubule-derived cell line (BUMPT) and C57BL/6J mice. Furthermore, the lncRNA148400 mediates ischemic injury-induced apoptosis of BUMPT cells. Mechanistically, lncRNA 148400 sponged miR-10b-3p to promote apoptosis via GRK4 upregulation. Finally, knockdown of lncRNA 148400 alleviated the I/R-induced deterioration of renal function, renal tubular injury, and cell apoptosis. In addition, cleaved caspase-3 is increased via targeting the miR-10b-3p/GRK4 axis. Collectively, these results showed that lncRNA 148400/miR-10b-3p/GRK4 axis mediated the development of ischemic AKI.


Assuntos
Injúria Renal Aguda , Células Epiteliais , Túbulos Renais Proximais , RNA Longo não Codificante , Animais , Camundongos , Injúria Renal Aguda/genética , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Apoptose/genética , Apoptose/fisiologia , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Camundongos Endogâmicos C57BL , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/genética , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Isquemia/genética , Isquemia/metabolismo
2.
Sci Rep ; 11(1): 16270, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34381142

RESUMO

mTOR inhibitors offer advantages after kidney transplantation including antiviral and antitumor activity besides facilitating low calcineurin inhibitor exposure to reduce nephrotoxicity. Concerns about adverse effects due to antiproliferative and antiangiogenic properties have limited their clinical use particularly early after transplantation. Interference with vascular endothelial growth factor (VEGF)-A, important for physiologic functioning of renal endothelial cells and tubular epithelium, has been implicated in detrimental renal effects of mTOR inhibitors. Low doses of Rapamycin (loading dose 3 mg/kg bodyweight, daily doses 1.5 mg/kg bodyweight) were administered in an allogenic rat kidney transplantation model resulting in a mean through concentration of 4.30 ng/mL. Glomerular and peritubular capillaries, tubular cell proliferation, or functional recovery from preservation/reperfusion injury were not compromised in comparison to vehicle treated animals. VEGF-A, VEGF receptor 2, and the co-receptor Neuropilin-1 were upregulated by Rapamycin within 7 days. Rat proximal tubular cells (RPTC) responded in vitro to hypoxia with increased VEGF-A and VEGF-R1 expression that was not suppressed by Rapamycin at therapeutic concentrations. Rapamycin did not impair proliferation of RPTC under hypoxic conditions. Low-dose Rapamycin early posttransplant does not negatively influence the VEGF network crucial for recovery from preservation/reperfusion injury. Enhancement of VEGF signaling peritransplant holds potential to further improve outcomes.


Assuntos
Transplante de Rim , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/fisiologia , Resultados Negativos , Regeneração/efeitos dos fármacos , Sirolimo/efeitos adversos , Animais , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Expressão Gênica/efeitos dos fármacos , Túbulos Renais Proximais/citologia , Masculino , Ratos Endogâmicos F344 , Ratos Endogâmicos Lew , Traumatismo por Reperfusão/genética , Sirolimo/administração & dosagem , Sirolimo/farmacologia , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/fisiologia
3.
Stem Cell Reports ; 16(1): 134-148, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-33306987

RESUMO

MicroRNAs (miRNAs) are gene expression regulators and they have been implicated in acquired kidney diseases and in renal development, mostly through animal studies. We hypothesized that the miR-199a/214 cluster regulates human kidney development. We detected its expression in human embryonic kidneys by in situ hybridization. To mechanistically study the cluster, we used 2D and 3D human embryonic stem cell (hESC) models of kidney development. After confirming expression in each model, we inhibited the miRNAs using lentivirally transduced miRNA sponges. This reduced the WT1+ metanephric mesenchyme domain in 2D cultures. Sponges did not prevent the formation of 3D kidney-like organoids. These organoids, however, contained dysmorphic glomeruli, downregulated WT1, aberrant proximal tubules, and increased interstitial capillaries. Thus, the miR-199a/214 cluster fine-tunes differentiation of both metanephric mesenchymal-derived nephrons and kidney endothelia. While clinical implications require further study, it is noted that patients with heterozygous deletions encompassing this miRNA locus can have malformed kidneys.


Assuntos
Diferenciação Celular , MicroRNAs/metabolismo , Antagomirs/metabolismo , Capilares/patologia , Técnicas de Cultura de Células , Regulação para Baixo , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/metabolismo , Modelos Biológicos , Neovascularização Fisiológica , Sialoglicoproteínas/genética , Sialoglicoproteínas/metabolismo , Proteínas WT1/genética , Proteínas WT1/metabolismo
4.
Sci Rep ; 9(1): 7883, 2019 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-31133638

RESUMO

In acute kidney injury (AKI), the S3 segment of the proximal tubule is particularly damaged, as it is most vulnerable to ischemia. However, this region is also involved in renal tubular regeneration. To deeply understand the mechanism of the repair process after ischemic injury in AKI, we focused on glial cells missing 1 (Gcm1), which is one of the genes expressed in the S3 segment. Gcm1 is essential for the development of the placenta, and Gcm1 knockout (KO) is embryonically lethal. Thus, the function of Gcm1 in the kidney has not been analyzed yet. We analyzed the function of Gcm1 in the kidney by specifically knocking out Gcm1 in the kidney. We created an ischemia-reperfusion injury (IRI) model to observe the repair process after AKI. We found that Gcm1 expression was transiently increased during the recovery phase of IRI. In Gcm1 conditional KO mice, during the recovery phase of IRI, tubular cell proliferation reduced and transforming growth factor-ß1 expression was downregulated resulting in a reduction in fibrosis. In vitro, Gcm1 overexpression promoted cell proliferation and upregulated TGF-ß1 expression. These findings indicate that Gcm1 is involved in the mechanisms of fibrosis and cell proliferation after ischemic injury of the kidney.


Assuntos
Injúria Renal Aguda/patologia , Proteínas de Ligação a DNA/metabolismo , Túbulos Renais Proximais/patologia , Regeneração/fisiologia , Traumatismo por Reperfusão/patologia , Fatores de Transcrição/metabolismo , Injúria Renal Aguda/etiologia , Animais , Proliferação de Células/fisiologia , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Regulação para Baixo , Feminino , Fibrose , Humanos , Túbulos Renais Proximais/irrigação sanguínea , Masculino , Camundongos , Camundongos Knockout , Traumatismo por Reperfusão/complicações , Fatores de Transcrição/genética , Fator de Crescimento Transformador beta1/metabolismo
5.
Proc Natl Acad Sci U S A ; 116(12): 5399-5404, 2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30833403

RESUMO

Three-dimensional renal tissues that emulate the cellular composition, geometry, and function of native kidney tissue would enable fundamental studies of filtration and reabsorption. Here, we have created 3D vascularized proximal tubule models composed of adjacent conduits that are lined with confluent epithelium and endothelium, embedded in a permeable ECM, and independently addressed using a closed-loop perfusion system to investigate renal reabsorption. Our 3D kidney tissue allows for coculture of proximal tubule epithelium and vascular endothelium that exhibits active reabsorption via tubular-vascular exchange of solutes akin to native kidney tissue. Using this model, both albumin uptake and glucose reabsorption are quantified as a function of time. Epithelium-endothelium cross-talk is further studied by exposing proximal tubule cells to hyperglycemic conditions and monitoring endothelial cell dysfunction. This diseased state can be rescued by administering a glucose transport inhibitor. Our 3D kidney tissue provides a platform for in vitro studies of kidney function, disease modeling, and pharmacology.


Assuntos
Túbulos Renais Proximais/metabolismo , Reabsorção Renal , Albuminas/metabolismo , Glucose/metabolismo , Humanos , Imageamento Tridimensional , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/ultraestrutura , Microscopia Eletrônica , Modelos Biológicos , Reabsorção Renal/fisiologia
6.
Kidney Int ; 94(3): 524-535, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30045814

RESUMO

Multiple large clinical trials have shown that sodium-glucose cotransporter (SGLT) 2 inhibitors reduce the risk of renal events. However, the mechanism responsible for this outcome remains unknown. Here we investigated the effects of the SGLT2 inhibitor luseogliflozin on the development of renal fibrosis after renal ischemia/reperfusion injury in non-diabetic mice. Luseogliflozin significantly suppressed development of renal fibrosis, prevented peritubular capillary congestion/hemorrhage, attenuated CD31-positive cell loss, suppressed hypoxia, and increased vascular endothelial growth factor (VEGF)-A expression in the kidney after ischemia/reperfusion injury. Luseogliflozin failed to induce the above-mentioned protection in animals co-treated with sunitinib, a VEGF receptor inhibitor. Additionally, luseogliflozin reduced glucose uptake and increased VEGF-A expression in the kidneys of glucose transporter 2 (GLUT2)-downregulated mice following ischemia/reperfusion and in GLUT2-knock-down cells compared with those in normal controls. Withdrawal of glucose from cultured medium, to halt glucose uptake, remarkably increased VEGF-A expression and reversed the luseogliflozin-induced increase in VEGF-A expression in the proximal tubular cells. Thus, luseogliflozin prevented endothelial rarefaction and subsequent renal fibrosis after renal ischemia/reperfusion injury through a VEGF-dependent pathway induced by the dysfunction of proximal tubular glucose uptake in tubules with injury-induced GLUT2 downregulation.


Assuntos
Injúria Renal Aguda/tratamento farmacológico , Túbulos Renais Proximais/patologia , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Transportador 2 de Glucose-Sódio/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/patologia , Inibidores da Angiogênese/farmacologia , Animais , Glicemia/metabolismo , Capilares/efeitos dos fármacos , Capilares/metabolismo , Capilares/patologia , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Fibrose , Técnicas de Silenciamento de Genes , Transportador de Glucose Tipo 2/genética , Transportador de Glucose Tipo 2/metabolismo , Humanos , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/patologia , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Sorbitol/análogos & derivados , Sorbitol/farmacologia , Sorbitol/uso terapêutico , Sunitinibe/farmacologia , Resultado do Tratamento
7.
Exp Mol Med ; 50(4): 1-17, 2018 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-29674665

RESUMO

Activation of the α7 nicotinic acetylcholine receptor (α7nAChR) has been shown to attenuate excessive inflammation by inhibiting proinflammatory cytokines during ischemia-reperfusion (IR) injury; however, the underlying kidney-specific molecular mechanisms remain unclear. The protective action of α7nAChR against renal IR injury was investigated using a selective α7nAChR agonist and antagonist. α7nAChR activation reduced plasma creatinine levels and tubular cell damage, whereas α7nAChR inhibition aggravated the IR-induced phenotype. α7nAChR activation decreased neutrophil infiltration and proinflammatory cytokine expression, increased heme oxygenase-1 (HO-1) expression, and reduced proximal tubular apoptosis after IR as shown by terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and caspase-3 cleavage. In this study, we first showed that α7nAChR activation in the proximal tubules induced HO-1 expression through the phosphoinositide 3-kinase (PI3K)/Akt and protein kinase C (PKC) signaling pathway in vivo in renal IR mice and in vitro in proximal tubular cells. Chemical inhibitors of PKC or PI3K/Akt and small interfering RNA-mediated PKC silencing confirmed the signal specificity of α7nAChR-mediated HO-1 induction in the proximal tubular cells. α7nAChR activation inhibited high-mobility group box 1 release by inducing HO-1 expression and reduced proinflammatory cytokine gene expression and apoptotic cell death in tumor necrosis factor α-stimulated proximal tubular cells. Taken together, we conclude that α7nAChR activation in proximal tubular cells directly protects cells against renal IR injury by inducing HO-1 expression through PI3K/Akt and PKC signaling.


Assuntos
Injúria Renal Aguda , Regulação Enzimológica da Expressão Gênica , Heme Oxigenase-1/biossíntese , Isquemia , Túbulos Renais Proximais , Proteínas de Membrana/biossíntese , Proteína Quinase C/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Injúria Renal Aguda/prevenção & controle , Animais , Isquemia/metabolismo , Isquemia/patologia , Isquemia/prevenção & controle , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Masculino , Camundongos
8.
Am J Physiol Renal Physiol ; 314(4): F501-F516, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29187371

RESUMO

The erythropoietin receptor (EpoR) is widely expressed but its renoprotective action is unexplored. To examine the role of EpoR in vivo in the kidney, we induced acute kidney injury (AKI) by ischemia-reperfusion in mice with different EpoR bioactivities in the kidney. EpoR bioactivity was reduced by knockin of wild-type human EpoR, which is hypofunctional relative to murine EpoR, and a renal tubule-specific EpoR knockout. These mice had lower EPO/EpoR activity and lower autophagy flux in renal tubules. Upon AKI induction, they exhibited worse renal function and structural damage, more apoptosis at the acute stage (<7 days), and slower recovery with more tubulointerstitial fibrosis at the subacute stage (14 days). In contrast, mice with hyperactive EpoR signaling from knockin of a constitutively active human EpoR had higher autophagic flux, milder kidney damage, and better renal function at the acute stage but, surprisingly, worse tubulointerstitial fibrosis and renal function at the subacute stage. Either excess or deficient EpoR activity in the kidney was associated with abnormal peritubular capillaries and tubular hypoxia, creating a "U-shaped" relationship. The direct effects of EpoR on tubular cells were confirmed in vitro by a hydrogen peroxide model using primary cultured proximal tubule cells with different EpoR activities. In summary, normal erythropoietin (EPO)/EpoR signaling in renal tubules provides defense against renal tubular injury maintains the autophagy-apoptosis balance and peritubular capillary integrity. High and low EPO/EpoR bioactivities both lead to vascular defect, and high EpoR activity overides the tubular protective effects in AKI recovery.


Assuntos
Injúria Renal Aguda/metabolismo , Capilares/metabolismo , Eritropoetina/metabolismo , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/metabolismo , Neovascularização Fisiológica , Receptores da Eritropoetina/metabolismo , Injúria Renal Aguda/genética , Injúria Renal Aguda/patologia , Injúria Renal Aguda/fisiopatologia , Animais , Apoptose , Autofagia , Capilares/patologia , Capilares/fisiopatologia , Hipóxia Celular , Células Cultivadas , Modelos Animais de Doenças , Fibrose , Humanos , Túbulos Renais Proximais/patologia , Túbulos Renais Proximais/fisiopatologia , Camundongos da Linhagem 129 , Camundongos Transgênicos , Receptores da Eritropoetina/deficiência , Receptores da Eritropoetina/genética , Transdução de Sinais
9.
Kidney Int ; 87(6): 1125-40, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25651362

RESUMO

MicroRNAs, activated by the enzyme Dicer1, control post-transcriptional gene expression. Dicer1 has important roles in the epithelium during nephrogenesis, but its function in stromal cells during kidney development is unknown. To study this, we inactivated Dicer1 in renal stromal cells. This resulted in hypoplastic kidneys, abnormal differentiation of the nephron tubule and vasculature, and perinatal mortality. In mutant kidneys, genes involved in stromal cell migration and activation were suppressed as were those involved in epithelial and endothelial differentiation and maturation. Consistently, polarity of the proximal tubule was incorrect, distal tubule differentiation was diminished, and elongation of Henle's loop attenuated resulting in lack of inner medulla and papilla in stroma-specific Dicer1 mutants. Glomerular maturation and capillary loop formation were abnormal, whereas peritubular capillaries, with enhanced branching and increased diameter, formed later. In Dicer1-null renal stromal cells, expression of factors associated with migration, proliferation, and morphogenic functions including α-smooth muscle actin, integrin-α8, -ß1, and the WNT pathway transcriptional regulator LEF1 were reduced. Dicer1 mutation in stroma led to loss of expression of distinct microRNAs. Of these, miR-214, -199a-5p, and -199a-3p regulate stromal cell functions ex vivo, including WNT pathway activation, migration, and proliferation. Thus, Dicer1 activity in the renal stromal compartment regulates critical stromal cell functions that, in turn, regulate differentiation of the nephron and vasculature during nephrogenesis.


Assuntos
Diferenciação Celular/genética , RNA Helicases DEAD-box/fisiologia , Neovascularização Fisiológica/genética , Néfrons/embriologia , Ribonuclease III/fisiologia , Actinas/metabolismo , Animais , Capilares/embriologia , Movimento Celular/genética , Proliferação de Células/genética , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Feminino , Expressão Gênica , Cadeias alfa de Integrinas/metabolismo , Glomérulos Renais/irrigação sanguínea , Glomérulos Renais/citologia , Glomérulos Renais/embriologia , Túbulos Renais/irrigação sanguínea , Túbulos Renais/citologia , Túbulos Renais/embriologia , Túbulos Renais Distais/irrigação sanguínea , Túbulos Renais Distais/citologia , Túbulos Renais Distais/embriologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/embriologia , Alça do Néfron/irrigação sanguínea , Alça do Néfron/citologia , Alça do Néfron/embriologia , Camundongos , MicroRNAs/genética , Néfrons/anormalidades , Néfrons/citologia , Organogênese/genética , Podócitos/fisiologia , Ribonuclease III/genética , Ribonuclease III/metabolismo , Células Estromais/fisiologia , Transcriptoma , Ureter/anormalidades , Via de Sinalização Wnt/genética
10.
Am J Physiol Endocrinol Metab ; 304(12): E1365-78, 2013 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-23632630

RESUMO

Matrix metalloproteinase-9 (MMP-9) causes adverse remodeling, whereas hydrogen sulfide (H2S) rescues organs in vascular diseases. The involvement of MMP-9 and H2S in diabetic renovascular remodeling is, however, not well characterized. We determined whether MMP-9 regulates H2S generation and whether H2S modulates connexin through N-methyl-d-aspartate receptor (NMDA-R)-mediated pathway in the diabetic kidney. Wild-type (WT, C57BL/6J), diabetic (Akita, C57BL/6J-Ins2(Akita)), MMP-9(-/-) (M9KO), double knockout (DKO) of Akita/MMP-9(-/-) mice and in vitro cell culture were used in our study. Hyperglycemic Akita mice exhibited increased level of MMP-9 and decreased production of H2S. H2S-synthesizing enzymes cystathionine-ß-synthase and cystathionine-γ-lyase were also diminished. In addition, increased expressions of NMDA-R1 and connexin-40 and -43 were observed in diabetic kidney. As expected, MMP-9 mRNA was not detected in M9KO kidneys. However, very thin protein expression and activity were detected. No other changes were noticed in M9KO kidney. In DKO mice, all the above molecules showed a trend toward baseline despite hyperglycemia. In vitro, glomerular endothelial cells treated with high glucose showed induction of MMP-9, attenuated H2S production, NMDA-R1 induction, and dysregulated conexin-40 and -43 expressions. Silencing MMP-9 by siRNA or inhibition of NMDA-R1 by MK801 or H2S treatment preserved connexin-40 and -43. We conclude that in diabetic renovascular remodeling MMP-9 plays a major role and that H2S has therapeutic potential to prevent adverse diabetic renal remodeling.


Assuntos
Nefropatias Diabéticas/metabolismo , Sulfeto de Hidrogênio/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Animais , Células Cultivadas , Nefropatias Diabéticas/genética , Maleato de Dizocilpina/farmacologia , Células Endoteliais/citologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Glicosúria Renal/genética , Glicosúria Renal/metabolismo , Glomérulos Renais/irrigação sanguínea , Glomérulos Renais/citologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/citologia , Metaloproteinase 9 da Matriz/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Interferente Pequeno/genética , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo
12.
Exp Toxicol Pathol ; 64(7-8): 733-41, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21296565

RESUMO

Mycotoxic nephropathy was induced in eighteen young pigs by mouldy diets containing 0.5 ppm ochratoxin A (OTA) and/or 10 ppm fumonisin B1 (FB1) for three months. While the most obvious damages provoked by OTA were seen in the kidneys as expressed by the strong degenerative changes in proximal tubules and fibrosis in kidneys, FB1 was found to induce an increase in permeability of vessels mainly in lung, brain, cerebellum or kidneys and slight to moderate degenerative changes in kidneys. Pathomorphological damages in pigs exposed to both mycotoxins simultaneously present a combination of the main lesions provoked by each mycotoxin alone being stronger in their expression. Biochemical investigations as expressed by the increase of serum creatinine, urea and enzyme activity of ASAT/ALAT and by the decrease of serum cholesterol, total protein, albumin and glucose were strongest in pigs exposed to both mycotoxins simultaneously as can be anticipated form the strongest lesions in the kidneys. Both mycotoxins and their combination were found to disturb powerfully humoral immune response in all experimental pigs as expressed by the strong decrease in antibody titer against Morbus Aujesky at days 21 and 35 after vaccination. Having in mind that the feed levels of the both mycotoxins as well as the exposure time and the pathological findings corresponded to those in some spontaneous cases of porcine nephropathy in Bulgaria and South Africa, it can be concluded that the same mycotoxins are involved in the observed field cases of that nephropathy.


Assuntos
Fumonisinas/toxicidade , Nefropatias/induzido quimicamente , Ocratoxinas/toxicidade , Ração Animal/análise , Ração Animal/toxicidade , Animais , Capilares/efeitos dos fármacos , Capilares/patologia , Modelos Animais de Doenças , Sinergismo Farmacológico , Feminino , Imunidade Humoral/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/patologia , Nefropatias/sangue , Nefropatias/imunologia , Nefropatias/patologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/patologia , Fígado/efeitos dos fármacos , Fígado/patologia , Pulmão/efeitos dos fármacos , Pulmão/patologia , Linfonodos/efeitos dos fármacos , Linfonodos/patologia , Masculino , Suínos
13.
Am J Physiol Renal Physiol ; 301(2): F387-95, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21561997

RESUMO

Renal proximal tubular epithelium can regenerate after various insults. To examine whether the tubular repair process is regulated by surrounding peritubular capillaries, we established an in vitro human tubulogenesis model that mimics in vivo tubular regeneration after injury. In this model, HGF, a potent renotropic factor, dose dependently induced tubular structures in human renal proximal tubular epithelial cells cultured in gels. Consistent with regenerating tubular cells after injury, HGF-induced tubular structures expressed a developmental gene, Pax-2, and a mesenchymal marker, vimentin, and formed a lumen with aquaporin-1 expression. Electron microscopic analysis showed the presence of microvilli on the apical site of the lumen, suggesting that these structures are morphologically equivalent to renal tubules in vivo. When cocultured with human umbilical vein endothelial cells (HUVEC), HGF-induced tubular formation was significantly enhanced. This could not be reproduced by the addition of VEGF, basic FGF, or PDGF. Protein array revealed that HUVEC produced various matrix metalloproteinases (MMPs). The stimulatory effects of coculture with HUVEC or HUVEC-derived conditional medium were almost completely abolished by addition of the tissue inhibitor of metalloproteinase (TIMP)-1 or TIMP-2. These data suggest that endothelial cell-derived factors including MMPs play a critical role in tubulogenesis and imply a potential role of peritubular capillary endothelium as a source of factor(s) required for tubular recovery after injury.


Assuntos
Fator de Crescimento de Hepatócito/fisiologia , Túbulos Renais Proximais/fisiologia , Regeneração , Animais , Movimento Celular , Proliferação de Células , Células Cultivadas , Técnicas de Cocultura , Células Endoteliais/metabolismo , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Humanos , Isquemia/patologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/patologia , Masculino , Metaloproteinases da Matriz/metabolismo , Ratos , Ratos Wistar
14.
Kidney Int ; 79(11): 1163-5, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21566638

RESUMO

Hexokinases have emerged as novel mediators of the antiapoptotic effects of growth factors in a wide variety of cells. These effects have been attributed to highly regulated direct physical and functional interactions with mitochondria. The demonstration that mitochondrial hexokinases can prevent apoptogenic 'Bax attack' in proximal tubule cells suggests a need to reexamine the specific contributions of hexokinases and glucose metabolism in this nephron segment and elsewhere within the kidney.


Assuntos
Células Epiteliais/enzimologia , Hexoquinase/metabolismo , Nefropatias/enzimologia , Túbulos Renais Proximais/enzimologia , Membranas Mitocondriais/enzimologia , Traumatismo por Reperfusão/enzimologia , Animais , Apoptose , Sobrevivência Celular , Células Epiteliais/patologia , Hexoquinase/genética , Humanos , Nefropatias/patologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/patologia , Membranas Mitocondriais/patologia , Transporte Proteico , Traumatismo por Reperfusão/patologia , Transdução de Sinais , Estresse Fisiológico , Proteína X Associada a bcl-2/metabolismo
15.
Kidney Int ; 80(2): 181-9, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21389969

RESUMO

An acute increase in the international normalized ratio (INR; a comparison of prothrombin time to monitor the effects of warfarin) over 3 in patients with chronic kidney disease (CKD) is often associated with an unexplained acute increase in serum creatinine (SC) and an accelerated progression of CKD. Kidney biopsy in a subset of these patients showed obstruction of the renal tubule by red blood cell casts, and this appears to be the dominant mechanism of the acute kidney injury. We termed this warfarin-related nephropathy (WRN), and previously reported cases of WRN only in patients with CKD. We now assess whether this occurs in patients without CKD, its risk factors, and consequences. In 15,258 patients who initiated warfarin therapy during a 5-year period, 4006 had an INR over 3 and SC measured at the same time; however, the large data set precluded individual patient clinical assessment. A presumptive diagnosis of WRN was made if the SC increased by over 0.3 mg/dl within 1 week after the INR exceeded 3 with no record of hemorrhage. WRN occurred in 20.5% of the entire cohort, 33.0% of the CKD cohort, and 16.5% of the no-CKD cohort. Other risk factors included age, diabetes mellitus, hypertension, and cardiovascular disease. The 1-year mortality was 31.1% with compared with 18.9% without WRN, an increased risk of 65%. Thus, WRN may be a common complication of warfarin therapy in high-risk patients and CKD doubles this risk. The mechanisms of these risks are unclear.


Assuntos
Nefropatias/induzido quimicamente , Nefropatias/epidemiologia , Varfarina/efeitos adversos , Biópsia , Doença Crônica , Agregação Eritrocítica , Humanos , Coeficiente Internacional Normatizado , Nefropatias/mortalidade , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/patologia , Mortalidade , Fatores de Risco
16.
Kidney Int ; 79(11): 1207-16, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21430642

RESUMO

Hexokinase (HK), the rate-limiting enzyme in glycolysis, controls cell survival by promoting metabolism and/or inhibiting apoptosis. Since HK isoforms I and II have mitochondrial targeting sequences, we attempted to separate the protective effects of HK on cell metabolism from those on apoptosis. We exposed renal epithelial cells to metabolic stress causing ATP depletion in the absence of glucose and found that this activated glycogen synthase kinase 3ß (GSK3ß) and Bax caused mitochondrial membrane injury and apoptosis. ATP depletion led to a progressive HK II dissociation from mitochondria, released mitochondrial apoptosis inducing factor and cytochrome c into the cytosol, activated caspase-3, and reduced cell survival. Compared with control, adenoviral-mediated HK I or II overexpression improved cell survival following stress, but did not prevent GSK3ß or Bax activation, improve ATP content, or reduce mitochondrial fragmentation. HK I or HK II overexpression increased mitochondria-associated isoform-specific HK content, and decreased mitochondrial membrane injury and apoptosis after stress. In vivo, HK II localized exclusively to the proximal tubule. Ischemia reduced total renal HK II content and dissociated HK II from proximal tubule mitochondria. In cells overexpressing HK II, Bax and HK II did not interact before or after stress. While the mechanism by which HK antagonizes Bax-mediated apoptosis is unresolved by these studies, one possible scenario is that the two proteins compete for a common binding site on the outer mitochondrial membrane.


Assuntos
Células Epiteliais/enzimologia , Hexoquinase/metabolismo , Nefropatias/enzimologia , Túbulos Renais Proximais/enzimologia , Membranas Mitocondriais/enzimologia , Traumatismo por Reperfusão/enzimologia , Estresse Fisiológico , Proteína X Associada a bcl-2/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Apoptose , Caspase 3/metabolismo , Sobrevivência Celular , Células Cultivadas , Citocromos c/metabolismo , Modelos Animais de Doenças , Células Epiteliais/patologia , Glucose/deficiência , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Hexoquinase/genética , Nefropatias/patologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/patologia , Camundongos , Membranas Mitocondriais/patologia , Gambás , Transporte Proteico , Traumatismo por Reperfusão/patologia , Transdução de Sinais , Fatores de Tempo , Transfecção
17.
Am J Physiol Renal Physiol ; 300(2): F488-98, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21048020

RESUMO

Peritubular vascular changes and hypoxia after glomerular injury may explain subsequent tubulointerstitial injury and fibrosis. Several studies suggested that the expected tubulointerstitial angiogenic response is actively suppressed in this setting. The mechanism of this aberrant response has not been clearly identified. We used a common model of glomerular injury in rats to assess vascular changes and to identify potential factors associated with this aberrant response. Anti-Thy1.1 antibody administration (1 or 4 weekly doses) led to a dose-dependent renal damage characterized by elevated urea and tubulointerstitial fibrosis as assessed by Picro-Sirius Red staining. We quantified peritubular capillaries using CD31 and CD34 immunohistochemistry and showed that tubular angiogenic dysregulation was associated with peritubular capillary rarefaction. Using laser capture microdissection, we demonstrated an early induction of fibrogenic and angiogenic factors in the glomeruli and a subsequent dysregulated angiogenic response in the tubulointerstitial compartment. Proximal tubules of anti-Thy1.1-treated animals had increased pigment epithelial-derived factor (PEDF) expression by immunohistochemistry. Protein taken by laser capture microdissection also showed that PEDF was upregulated. Temporally associated with PEDF expression was a transient downregulation of tubular hypoxia-inducible factor (HIF)1α. In a human proximal tubular cell culture, we show that PEDF downregulates HIF1α protein and gene expression in cells exposed to 1% oxygen. In anti-Thy1.1 glomerulonephritis, there is aberrent tubular angiogenesis associated with glomerular injury and tubulointersititial fibrosis. We showed that PEDF may be involved by downregulating HIF1α. Further work is needed to elucidate the mechanism of PEDF upregulation and action in the tubules.


Assuntos
Glomerulonefrite/fisiopatologia , Túbulos Renais Proximais/fisiopatologia , Neovascularização Patológica/fisiopatologia , Animais , Antígenos CD34/análise , Antígenos CD34/imunologia , Linhagem Celular , Regulação para Baixo , Proteínas do Olho/metabolismo , Feminino , Glomerulonefrite/patologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Falência Renal Crônica/fisiopatologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/patologia , Fatores de Crescimento Neural/metabolismo , Molécula-1 de Adesão Celular Endotelial a Plaquetas/análise , Molécula-1 de Adesão Celular Endotelial a Plaquetas/imunologia , Ratos , Ratos Sprague-Dawley , Serpinas/metabolismo , Antígenos Thy-1/imunologia , Regulação para Cima , Ureia/sangue , Fator A de Crescimento do Endotélio Vascular/análise , Fator A de Crescimento do Endotélio Vascular/metabolismo
18.
Biomed Res ; 30(4): 251-8, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19729856

RESUMO

Acute renal failure (ARF) occurs in septic patients and is histologically characterized by tubular apical damages, including brush border breakdown. Nevertheless, little information is available to identify the apical injury at a molecular level. Type 2a Na-phosphate (Pi) co-transporter (NaPiT2a) is constitutively expressed by brush borders of proximal tubules under a healthy condition. Therefore, we investigated if NaPiT2a could be used as a negative marker to predict the renal dysfunction, using an animal model of septic ARF. After the treatment of lipopolysaccharide (LPS), mice manifested the tubular apical injury and renal dysfunction, as evidenced by the increase in blood urea nitrogen (BUN) levels. Immunohistochemical examination revealed that the expression of NaPiT2a by renal proximal tubules became faint, being reciprocal to the development of tubular hypoxia during sepsis. Inversely, the loss in apical NaPiT2a was restored in a regenerating stage, associated with the recovery from renal hypoxia. Overall, there was a negative correlation between the NaPiT2a expression and BUN levels or tubular injury scores in septic mice. Our data indicate that the loss of NaPiT2a is a reliable marker for predicting the progression of septic ARF, while local hypoxia might be involved in the decrease of NaPiT2a expression.


Assuntos
Injúria Renal Aguda/metabolismo , Túbulos Renais Proximais/metabolismo , Sepse/metabolismo , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIa/biossíntese , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/patologia , Animais , Biomarcadores/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Hipóxia/induzido quimicamente , Hipóxia/metabolismo , Hipóxia/patologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/patologia , Lipopolissacarídeos/toxicidade , Camundongos , Sepse/induzido quimicamente , Sepse/patologia
19.
Apoptosis ; 14(10): 1176-89, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19685188

RESUMO

Reactive oxygen species (ROS) contribute significantly to apoptosis in renal ischemia-reperfusion (IR) injury, however the exact mechanisms are not well understood. We used novel lentiviral vectors to over-express superoxide dismutase 1 (SOD1) in proximal tubular epithelial (LLC-PK(1)) cells and determined effects of SOD1 following ATP depletion-recovery, used as a model to simulate renal IR. SOD1 over-expression partially protected against cytotoxicity (P < 0.001) and decreased superoxide (O(2) (*-)) in ATP depleted cells. The ATP depletion-mediated increase in nuclear fragmentation, an index of apoptosis and activation of caspase-3 was also partially blocked by SOD1 (P < 0.05). However, SOD1 over-expression was insufficient to completely attenuate caspase-3, indicating that ROS other than cytoplasmic O(2) (*-) are involved in ATP depletion mediated injury. To test the contribution of hydrogen peroxide, a subset of enhanced green fluorescent protein (EGFP) and SOD1 (serum free and injured) cells were treated with polyethylene glycol-catalase (PEG-catalase). As expected there was 50% reduction in cytotoxicity and caspase-3 in SOD1 cells compared to EGFP cells; catalase treatment decreased both indices by an additional 28% following ATP depletion. To test the role of mitochondrial derived superoxide, we also treated a subset of LLC-PK(1) cells with the mitochondrial antioxidant, MitoTEMPO. Treatment with MitoTEMPO also decreased ATP depletion induced cytotoxicity in LLC-PK(1) cells in a dose dependant manner. These studies indicate that both SOD1 dependent and independent pathways are integral in protection against ATP depletion-recovery mediated cytotoxicity and apoptosis, however more studies are needed to delineate the signaling mechanisms involved.


Assuntos
Apoptose , Células Epiteliais/enzimologia , Isquemia/enzimologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/citologia , Superóxido Dismutase/metabolismo , Trifosfato de Adenosina/deficiência , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Catalase/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Vetores Genéticos/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , L-Lactato Desidrogenase/metabolismo , Células LLC-PK1 , Lentivirus/genética , Piperidinas/farmacologia , Reprodutibilidade dos Testes , Superóxido Dismutase-1 , Superóxidos/metabolismo , Suínos , Fatores de Tempo
20.
Nephron Physiol ; 113(4): p23-8, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19713718

RESUMO

BACKGROUND/AIMS: Disrupting the enzyme Cyp4a14 in mice leads to hypertension, which is more severe in the male mice and appears to be due to androgen excess. Because the Cyp4a14 enzyme is located in the proximal tubule of the kidney, we hypothesized that there could be dysregulation of transport in this segment that could contribute to the hypertension. METHODS: Wild-type (SV/129) mice and mice that had targeted disruption of the Cyp4a14 gene were studied. Proximal convoluted tubules (PCT) from knockout and wild-type mice were dissected and perfused in vitrofor measurement of volume absorption (J(V)). Expression of the sodium-hydrogen exchanger 3 (NHE3), the predominant transporter responsible for sodium transport in this segment, was measured by immunoblot. Renal vascular (afferent arteriole) responses to angiotensin and endothelin were also measured. RESULTS: PCT volume absorption was elevated in tubules from the Cyp4a14 knockout mice as compared to the wild-type mice. Brush border membrane NHE3 expression was almost 2-fold higher in Cyp4a14 knockout mice than in wild-type mice. No difference was found in the afferent arteriolar response. CONCLUSION: Thus, hypertension in the Cyp4a14 knockout mice appears to be driven by excessive fluid reabsorption in the proximal tubule, which is secondary to overexpression of NHE3.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Hipertensão/metabolismo , Túbulos Renais Proximais/metabolismo , Androgênios/metabolismo , Animais , Arteríolas/fisiologia , Transporte Biológico/fisiologia , Pressão Sanguínea/fisiologia , Sistema Enzimático do Citocromo P-450/genética , Família 4 do Citocromo P450 , Modelos Animais de Doenças , Hipertensão/genética , Túbulos Renais Proximais/irrigação sanguínea , Masculino , Camundongos , Camundongos Knockout , Sódio/metabolismo , Trocador 3 de Sódio-Hidrogênio , Trocadores de Sódio-Hidrogênio/metabolismo
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