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1.
Int J Mol Sci ; 21(9)2020 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-32380787

RESUMO

Coronaviruses (CoVs), including Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and the novel coronavirus disease-2 (SARS-CoV-2) are a group of enveloped RNA viruses that cause a severe respiratory infection which is associated with a high mortality [...].


Assuntos
Lesão Renal Aguda/mortalidade , Lesão Renal Aguda/virologia , Betacoronavirus/patogenicidade , Infecções por Coronavirus/virologia , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/virologia , Pneumonia Viral/virologia , Lesão Renal Aguda/fisiopatologia , Lesão Renal Aguda/prevenção & controle , Angiotensina II/farmacologia , Catepsinas/metabolismo , Morte Celular/efeitos dos fármacos , Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/patologia , Infecções por Coronavirus/fisiopatologia , Creatinina/sangue , Estado Terminal/mortalidade , Endossomos/efeitos dos fármacos , Endossomos/enzimologia , Endossomos/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Incidência , Túbulos Renais Proximais/fisiopatologia , Lisossomos/efeitos dos fármacos , Lisossomos/enzimologia , Lisossomos/metabolismo , Pandemias , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/mortalidade , Pneumonia Viral/patologia , Pneumonia Viral/fisiopatologia , Receptores Virais/metabolismo , Síndrome Respiratória Aguda Grave/sangue , Síndrome Respiratória Aguda Grave/mortalidade , Síndrome Respiratória Aguda Grave/fisiopatologia , Internalização do Vírus , Replicação Viral
2.
PLoS One ; 15(2): e0229618, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084244

RESUMO

Prenatal hypoxia is a gestational stressor that can result in developmental abnormalities or physiological reprogramming, and often decreases cellular capacity against secondary stress. When a developing fetus is exposed to hypoxia, blood flow is preferentially redirected to vital organs including the brain and heart over other organs including the kidney. Hypoxia-induced injury can lead to structural malformations in the kidney; however, even in the absence of structural lesions, hypoxia can physiologically reprogram the kidney leading to decreased function or increased susceptibility to injury. Our investigation in mice reveals that while prenatal hypoxia does not affect normal development of the kidneys, it primes the kidneys to have an increased susceptibility to kidney injury later in life. We found that our model does not develop structural abnormalities when prenatally exposed to modest 12% O2 as evident by normal histological characterization and gene expression analysis. Further, adult renal structure and function is comparable to mice exposed to ambient oxygen throughout nephrogenesis. However, after induction of kidney injury with a nephrotoxin (cisplatin), the offspring of mice housed in hypoxia exhibit significantly reduced renal function and proximal tubule damage following injury. We conclude that exposure to prenatal hypoxia in utero physiologically reprograms the kidneys leading to increased susceptibility to injury later in life.


Assuntos
Lesão Renal Aguda/etiologia , Hipóxia/metabolismo , Rim/metabolismo , Lesão Renal Aguda/embriologia , Animais , Cisplatino/efeitos adversos , Cisplatino/farmacologia , Feminino , Hipóxia Fetal/fisiopatologia , Hemodinâmica , Hipóxia/fisiopatologia , Rim/embriologia , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oxigênio/metabolismo , Gravidez , Efeitos Tardios da Exposição Pré-Natal/metabolismo
3.
Am J Med Sci ; 359(2): 79-83, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32039769

RESUMO

BACKGROUND: The hexosamine biosynthesis pathway (HBP) is hypothesized to mediate many of the adverse effects of hyperglycemia. We have shown previously that increased flux through this pathway leads to induction of the growth factor transforming growth factor-α (TGF-α) and to insulin resistance in cultured cells and transgenic mice. TGF-ß is regulated by glucose and is involved in the development of diabetic nephropathy. We therefore hypothesized that the HBP was involved in the regulation of TGF-ß by glucose in rat vascular and kidney cells. METHODS: A plasmid containing the promoter region of TGF-ß1 cloned upstream of the firefly luciferase gene was electroporated into rat aortic smooth muscle, mesangial, and proximal tubule cells. Luciferase activity was measured in cellular extracts from cells cultured in varying concentrations of glucose and glucosamine. RESULTS: Glucose treatment of all cultured cells led to a time- and dose-dependent stimulation in TGF-ß1 transcriptional activity, with high (20 mM) glucose causing a 1.4- to 2.0-fold increase. Glucose stimulation did not occur until after 12 hours and disappeared after 72 hours of treatment. Glucosamine was more potent than glucose, with 3 mM stimulating up to a 4-fold increase in TGFß1-transcriptional activity. The stimulatory effect of glucosamine was also dose-dependent but was slower to develop and longer lasting than that of glucose. CONCLUSIONS: The metabolism of glucose through the HBP mediates extracellular matrix production, possibly via the stimulation of TGF-ß in kidney cells. Hexosamine metabolism therefore, may play a role in the development of diabetic nephropathy.


Assuntos
Nefropatias Diabéticas/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/farmacologia , Hexosaminas/biossíntese , Túbulos Renais Proximais/metabolismo , Células Mesangiais/metabolismo , Transcrição Genética/efeitos dos fármacos , Fator de Crescimento Transformador beta1/biossíntese , Animais , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Matriz Extracelular/genética , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Glucose/metabolismo , Hexosaminas/genética , Humanos , Túbulos Renais Proximais/patologia , Células Mesangiais/patologia , Camundongos , Camundongos Transgênicos , Ratos , Fatores de Tempo , Fator de Crescimento Transformador beta1/genética
4.
Nat Commun ; 11(1): 294, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941925

RESUMO

Cells subjected to stress situations mobilize specific membranes and proteins to initiate autophagy. Phosphatidylinositol-3-phosphate (PI3P), a crucial lipid in membrane dynamics, is known to be essential in this context. In addition to nutriments deprivation, autophagy is also triggered by fluid-flow induced shear stress in epithelial cells, and this specific autophagic response depends on primary cilium (PC) signaling and leads to cell size regulation. Here we report that PI3KC2α, required for ciliogenesis and PC functions, promotes the synthesis of a local pool of PI3P upon shear stress. We show that PI3KC2α depletion in cells subjected to shear stress abolishes ciliogenesis as well as the autophagy and related cell size regulation. We finally show that PI3KC2α and VPS34, the two main enzymes responsible for PI3P synthesis, have different roles during autophagy, depending on the type of cellular stress: while VPS34 is clearly required for starvation-induced autophagy, PI3KC2α participates only in shear stress-dependent autophagy.


Assuntos
Autofagia/fisiologia , Cílios/fisiologia , Fosfatidilinositol 3-Quinases/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Animais , Linhagem Celular , Tamanho Celular , Classe III de Fosfatidilinositol 3-Quinases/genética , Classe III de Fosfatidilinositol 3-Quinases/metabolismo , Regulação Enzimológica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Fosfatidilinositol 3-Quinases/genética , Estresse Mecânico
5.
Am J Physiol Renal Physiol ; 318(2): F402-F421, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31841393

RESUMO

Hypokalemia increases ammonia excretion and decreases K+ excretion. The present study examined the role of the proximal tubule protein NBCe1-A in these responses. We studied mice with Na+-bicarbonate cotransporter electrogenic, isoform 1, splice variant A (NBCe1-A) deletion [knockout (KO) mice] and their wild-type (WT) littermates were provided either K+ control or K+-free diet. We also used tissue sections to determine the effect of extracellular ammonia on NaCl cotransporter (NCC) phosphorylation. The K+-free diet significantly increased proximal tubule NBCe1-A and ammonia excretion in WT mice, and NBCe1-A deletion blunted the ammonia excretion response. NBCe1-A deletion inhibited the ammoniagenic/ammonia recycling enzyme response in the cortical proximal tubule (PT), where NBCe1-A is present in WT mice. In the outer medulla, where NBCe1-A is not present, the PT ammonia metabolism response was accentuated by NBCe1-A deletion. KO mice developed more severe hypokalemia and had greater urinary K+ excretion during the K+-free diet than did WT mice. This was associated with blunting of the hypokalemia-induced change in NCC phosphorylation. NBCe1-A KO mice have systemic metabolic acidosis, but experimentally induced metabolic acidosis did not alter NCC phosphorylation. Although KO mice have impaired ammonia metabolism, experiments in tissue sections showed that lack of ammonia does impair NCC phosphorylation. Finally, urinary aldosterone was greater in KO mice than in WT mice, but neither expression of epithelial Na+ channel α-, ß-, and γ-subunits nor of H+-K+-ATPase α1- or α2-subunits correlated with changes in urinary K+. We conclude that NBCe1-A is critical for the effect of diet-induced hypokalemia to increase cortical proximal tubule ammonia generation and for the expected decrease in urinary K+ excretion.


Assuntos
Amônia/urina , Hipopotassemia/metabolismo , Túbulos Renais Proximais/metabolismo , Potássio na Dieta/sangue , Eliminação Renal , Simportadores de Sódio-Bicarbonato/metabolismo , Acidose/genética , Acidose/metabolismo , Acidose/fisiopatologia , Aldosterona/urina , Animais , Biomarcadores/sangue , Biomarcadores/urina , Modelos Animais de Doenças , Canais Epiteliais de Sódio/metabolismo , Glutamato-Amônia Ligase/metabolismo , ATPase Trocadora de Hidrogênio-Potássio/genética , ATPase Trocadora de Hidrogênio-Potássio/metabolismo , Hipopotassemia/genética , Hipopotassemia/fisiopatologia , Túbulos Renais Proximais/fisiopatologia , Camundongos Knockout , Fosforilação , Simportadores de Sódio-Bicarbonato/deficiência , Simportadores de Sódio-Bicarbonato/genética , Membro 3 da Família 12 de Carreador de Soluto/metabolismo
6.
Mol Immunol ; 118: 117-123, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31874343

RESUMO

Acute kidney injury (AKI) has one of the highest mortalities in terms of inflammatory sepsis. MiR-20a is involved in a variety of inflammatory reactions, but its role in AKI remains unknown. The purpose of this study was to investigate specific in vitro function and mechanisms of miR-20a in AKI. We used, lipopolysaccharide (LPS) against human proximal tubular epithelial (HK-2) cells to induce an in vitro model of AKI. Then, our data showed that miR-20a expression levels were down-regulated in LPS-treated HK-2 cells. Overexpression of miR-20a promoted cell viability, inhibited apoptosis rate and inhibited the expression of apoptotic factors and inflammatory cytokines in HK-2 cells after LPS stimulation. In addition, CXCL12 was identified as a direct target of miR-20a by luciferase reporter gene assay, and CXCL12 expression was negatively regulated by miR-20a. Moreover, CXCR4 attenuated the suppression of miR-20a on inflammation and apoptosis in LPS-stimulated HK-2 cells, and further data indicated that miR-20a deactivated CXCL12/CXCR-4, NFκB and ERK1/2 signaling by targeting CXCL12. Therefore, our data revealed that miR-20a may play an anti-inflammatory and antiapoptotic roles in LPS-induced HK-2 cells via deactivation of CXCL12/CXCR-4, NFκB and ERK1/2 signaling.


Assuntos
Lesão Renal Aguda/metabolismo , Quimiocina CXCL12/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , MicroRNAs/metabolismo , NF-kappa B/metabolismo , Transdução de Sinais/fisiologia , Lesão Renal Aguda/induzido quimicamente , Apoptose/fisiologia , Linhagem Celular , Sobrevivência Celular/fisiologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos , Inflamação/metabolismo , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Lipopolissacarídeos/farmacologia
7.
Int J Mol Sci ; 21(1)2019 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-31881660

RESUMO

Renal proximal tubular epithelial cells are significantly damaged during acute kidney injury. Renal proximal tubular cell-specific autophagy-deficient mice show increased sensitivity against renal injury, while showing few pathological defects under normal fed conditions. Considering that autophagy protects the proximal tubular cells from acute renal injury, it is reasonable to assume that autophagy contributes to the maintenance of renal tubular cells under normal fed conditions. To clarify this possibility, we generated a knock out mouse model which lacks Atg7, a key autophagosome forming enzyme, in renal proximal tubular cells (Atg7flox/flox;KAP-Cre+). Analysis of renal tissue from two months old Atg7flox/flox;KAP-Cre+ mouse revealed an accumulation of LC3, binding protein p62/sequestosome 1 (a selective substrate for autophagy), and more interestingly, Kim-1, a biomarker for early kidney injury, in the renal proximal tubular cells under normal fed conditions. TUNEL (TdT-mediated dUTP Nick End Labeling)-positive cells were also detected in the autophagy-deficient renal tubular cells. Analysis of renal tissue from Atg7flox/flox;KAP-Cre+ mice at different age points showed that tubular cells positive for p62 and Kim-1 continually increase in number in an age-dependent manner. Ultrastructural analysis of tubular cells from Atg7flox/flox;KAP-Cre+ revealed the presence of intracellular inclusions and abnormal structures. These results indicated that autophagy-deficiency in the renal proximal epithelial tubular cells leads to an increase in injured cells in the kidney even under normal fed conditions.


Assuntos
Apoptose , Proteína 7 Relacionada à Autofagia/genética , Autofagia , Envelhecimento , Animais , Proteína 7 Relacionada à Autofagia/deficiência , Receptor Celular 1 do Vírus da Hepatite A/metabolismo , Rim/metabolismo , Rim/patologia , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/ultraestrutura , Camundongos , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/metabolismo , Proteína Sequestossoma-1/metabolismo
8.
Cell Physiol Biochem ; 53(4): 713-730, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31599538

RESUMO

BACKGROUND/AIMS: Renal injury related to hypertension is characterized by glomerular and tubulointerstitial damage. The overactivation of the renin-angiotensin system mainly by angiotensin II (AII) seems to be a main contributor to progressive renal fibrosis. Epithelial to mesenchymal transition (EMT) is a mechanism that promotes renal fibrosis. Owing to heat shock protein 70 (Hsp70) cytoprotective properties, the chaperone exhibits an important potential as a therapeutic target. We investigate the role of Hsp70 on Angiotensin II induced epithelial mesenchymal transition within the Losartan effect in proximal tubule cells (PTCs) from a genetic model of hypertension in rats (SHR). METHODS: Primary cell culture of PTCs from SHR and Wistar Kyoto (WKY) rats were stimulated with AII, treated with Losartan (L), (L+AII) or untreated (Cc). The functional Hsp70 role in Losartan effect, after silencing its expression by cell transfection, was determined by Immunofluorescence; Western blotting; Gelatin Zymography assays; Scratch wound assays; flow cytometry; and Live Cell Time-lapse microscopy. RESULTS: (L) and (L+AII) treatments induced highly organized actin filaments and increased cortical actin in SHR PTCs. However, SHR PTCs (Cc) and (AII) treated cells showed disorganized actin. After Hsp72 knockdown in SHR PTCs, (L) was unable to stabilize the actin cytoskeleton. We demonstrated that (L) and (L+AII) increased E-cadherin levels and decreased vinculin, α-SMA, vimentin, pERK, p38 and Smad2-3 activation compared to (AII) and (Cc) SHR PTCs. Moreover, (L) inhibited MMP-2 and MMP-9 secretion, reduced migration and cellular displacement, stabilizing intercellular junctions. Notably, (L) treatment in shHsp72 knockdown SHR PTCs showed results similar to SHR PTCs (Cc). CONCLUSION: Our results demonstrate that Losartan through Hsp70 inhibits the EMT induced by AII in proximal tubule cells derived from SHR.


Assuntos
Angiotensina II/farmacologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/metabolismo , Losartan/farmacologia , Citoesqueleto de Actina/efeitos dos fármacos , Animais , Caderinas/metabolismo , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Adesões Focais/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Proteínas de Choque Térmico HSP70/genética , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/metabolismo , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Vinculina/metabolismo
9.
Anticancer Res ; 39(10): 5515-5524, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31570445

RESUMO

BACKGROUND/AIM: Administration of cisplatin in cancer patients is limited by the kidney-related adverse effects; however, a protective strategy is absent. We hypothesized that fucoidan protects the proximal tubule epithelial (TH-1) cells against the effects of cisplatin. MATERIALS AND METHODS: To assess the effect of fucoidan, its effect on reactive oxygen species (ROS) formation, endoplasmic reticulum (ER) stress response, DNA damage response (DDR), apoptosis, and cell-cycle arrest in TH-1 cells was investigated. RESULTS: Cisplatin increased the accumulation of ROS, leading to excessive ER stress. In presence of cisplatin, treatment of TH-1 cells with fucoidan significantly reduced the ER stress by maintaining the complex of GRP78 with PERK and IRE1α. In particular, fucoidan enhanced the antioxidative capacity through up-regulation of PrPC Furthermore, fucoidan suppressed cisplatin-induced apoptosis and cell-cycle arrest, whereas silencing of PRNP blocked these effects of fucoidan. CONCLUSION: Fucoidan may be a potential adjuvant therapy for cancer patients treated with cisplatin as it preserves renal functionality.


Assuntos
Cisplatino/farmacologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Túbulos Renais Proximais/efeitos dos fármacos , Polissacarídeos/farmacologia , Substâncias Protetoras/farmacologia , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Células Epiteliais/metabolismo , Proteínas de Choque Térmico/metabolismo , Humanos , Rim/efeitos dos fármacos , Rim/metabolismo , Túbulos Renais Proximais/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Células Th1/efeitos dos fármacos , Células Th1/metabolismo , Regulação para Cima/efeitos dos fármacos , eIF-2 Quinase/metabolismo
10.
Toxicol Lett ; 317: 110-119, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31618666

RESUMO

Trichloroethylene (TCE), a commonly used industrial solvent and degreasing agent, is known to cause trichloroethylene hypersensitivity syndrome (THS) with multi-system damage, including skin, liver and kidney. Clinical evidence have shown that the kidney injury occurs in THS and our previous studies suggested that the terminal complement complex C5b-9 deposited in impaired renal tubules induced by TCE with unclear mechanisms. In the present study, we questioned whether activation of the complement system with renal deposition of C5b-9 contributes to TCE-induced kidney injury in THS. We established a BALB/c mouse model of TCE sensitization with or without pretreatment of exogenous CD59, a C5b-9 inhibitory protein. H&E staining, PAS staining, and biochemical detection of urinary proteins were performed to assess renal function. Deposition of C5b-9 and expression of CD59 were evaluated by immunohistochemistry. Sub-lytic effects of C5b-9 in tubular epithelial cells were assessed by lactate dehydrogenase (LDH) cytotoxicity assay. Expression of endocytosis receptors megalin and cubilin on proximal tubules were assessed by immunofluorescence and qRT-PCR. We found that TCE sensitization induced structural and functional changes of renal tubules in mice, associated with the deposition of sub-lytic C5b-9 on proximal tubular epithelial cells. TCE sensitization decreased proximal tubule uptake of filtered proteins and renal expression of megalin and cubilin, phenotypes that were attenuated by pretreatment with exogenous CD59. Overall, our findings reveal a novel mechanism underlying sub-lytic C5b-9 acting on megalin and cubilin, contributes to the renal tubules damage by TCE exposure.


Assuntos
Complexo de Ataque à Membrana do Sistema Complemento/metabolismo , Endocitose , Hipersensibilidade/metabolismo , Nefropatias/metabolismo , Túbulos Renais Proximais/metabolismo , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Receptores de Superfície Celular/metabolismo , Tricloroetileno , Animais , Células Cultivadas , Ativação do Complemento , Complexo de Ataque à Membrana do Sistema Complemento/imunologia , Modelos Animais de Doenças , Feminino , Hipersensibilidade/imunologia , Hipersensibilidade/patologia , Nefropatias/induzido quimicamente , Nefropatias/imunologia , Nefropatias/patologia , Túbulos Renais Proximais/imunologia , Túbulos Renais Proximais/patologia , Camundongos Endogâmicos BALB C , Transporte Proteico
11.
Int J Mol Sci ; 20(19)2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31547201

RESUMO

Although the kidneys comprise a critical target of uranium exposure, the dynamics of renal uranium distribution have remained obscure. Uranium is considered to function physiologically in the form of uranyl ions that have high affinity for phosphate groups. The present study applied microbeam-based elemental analysis to precisely determine the distribution of phosphorus and uranium in the kidneys of male Wistar rats exposed to uranium. One day after a single subcutaneous injection of uranyl acetate (2 mg/kg), areas of concentrated phosphorus were scattered in the S3 segments of the proximal tubule of the kidneys, whereas the S3 segments in control rats and in rats given a lower dose of uranium (0.5 mg/kg) contained phosphorus without concentrated phosphorus. Areas with concentrated phosphorus contained uranium 4- to 14-fold more than the mean uranium concentration (126-472 vs. 33.1 ± 4.6 µg/g). The chemical form of uranium in the concentrated phosphorus examined by XAFS was uranium (VI), suggesting that the interaction of uranyl ions with the phosphate groups of biomolecules could be involved in the formation of uranium concentration in the proximal tubules of kidneys in rats exposed to uranium.


Assuntos
Túbulos Renais Proximais/metabolismo , Compostos Organometálicos , Fósforo/metabolismo , Urânio/metabolismo , Animais , Túbulos Renais Proximais/patologia , Masculino , Compostos Organometálicos/farmacocinética , Compostos Organometálicos/farmacologia , Ratos , Ratos Wistar
12.
J Toxicol Sci ; 44(9): 611-619, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31474742

RESUMO

The kidney proximal tubule is a target of many renal toxicants, including cadmium (Cd), and also a place of reabsorption of essential metals in glomerular filtrate to systemic circulation. Although the mechanisms of metal transport in the convoluted proximal tubule (S1 and S2 segments) and the straight proximal tubule (S3 segment) may differ, little is known about the segment-specific modes of metal transport. Here, we utilized immortalized cell lines derived from the S1, S2, and S3 segments of mouse kidney proximal tubules, and examined the segment-specific and direction-dependent transport of Cd and manganese (Mn) using a trans-well culture system. The results showed that the uptakes of Cd2+ and Mn2+ from apical sides were the highest in S3 cells, and Cd2+, Mn2+, and Zn2+ mutually inhibited the apical uptake of each metal. As the expression of ZIP8, a zinc transporter having affinities for Cd2+ and Mn2+, was the highest in S3 cells, ZIP8 may contribute largely to the apical uptakes of these metals. The efficient uptake of Mn2+ from apical side of S3 cells may suggest an important role of ZIP8 in proximal tubule in reabsorption of Mn, an essential metal. Our study demonstrated that S1, S2, and S3 cells provide a useful tool for studying the segment-specific and direction-dependent transport of both toxic and essential metals in the kidney's proximal tubules.


Assuntos
Compostos de Cádmio/metabolismo , Compostos de Cádmio/toxicidade , Cádmio/metabolismo , Cádmio/toxicidade , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/metabolismo , Manganês/metabolismo , Manganês/toxicidade , Animais , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Transporte de Cátions/fisiologia , Células Cultivadas , Camundongos , Transcitose
13.
Life Sci ; 234: 116755, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31415769

RESUMO

AIMS: Vitamin D and its receptor, vitamin D receptor (VDR), have renoprotection effect against diabetic nephropathy (DN). But the exact mechanism has not been fully elucidated. Epoxyeicosatrienoic acids (EETs) are cytochrome P450 (CYP) epoxygenase-derived metabolites of arachidonic acid, protecting against diabetes and DN. Herein, we hypothesized that activation of VDR attenuated high glucose-induced cellular injury in renal tubular epithelial cells partially through up-regulating CYP2J5 expression. MAIN METHODS: Streptozotocin (STZ) was injected to induce diabetic in wild type and Vdr-/- mice. The effects of VDR knockout and an activator of VDR, paricalcitol, on the renal injury were detected. In vitro, a murine kidney proximal tubule epithelial cell line BU.MPT induced by high glucose were treated with or without paricalcitol (30 mM) for 12 h or 24 h. KEY FINDINGS: The expression of CYP2J5 was significantly decreased both in wild type and Vdr-/- diabetic mice induced by STZ. The STZ-induced kidney architecture damage and apoptosis rate in Vdr-/- mice were more severe. In vitro, high glucose treatment strongly reduced the CYP2J5 expression and the synthesis of 14,15-EET in BU.MPT cells. Supplement of 14,15-EET significantly reduced the lactate dehydrogenase (LDH) release induced by high glucose in BU.MPT cells. Furthermore, treatment with paricalcitol attenuated cellular injury and restored the expression of CYP2J5 reduced by high glucose in BU.MPT cells. SIGNIFICANCE: We conclude that activation of VDR attenuates high glucose-induced cellular injury partially dependent on CYP2J5 in murine renal tubule epithelial cells and paricalcitol may represent a potential therapy for DN.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Diabetes Mellitus Experimental/complicações , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/etiologia , Ergocalciferóis/farmacologia , Túbulos Renais Proximais/efeitos dos fármacos , Receptores de Calcitriol/agonistas , Animais , Linhagem Celular , Sistema Enzimático do Citocromo P-450/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/patologia , Ergocalciferóis/uso terapêutico , Deleção de Genes , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , Masculino , Camundongos , Camundongos Knockout , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo
14.
Int J Mol Sci ; 20(17)2019 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-31450703

RESUMO

Mitogen-activated protein kinases (MAPKs) are intracellular molecules regulating a wide range of cellular functions, including proliferation, differentiation, apoptosis, cytoskeleton remodeling and cytokine production. MAPK activity has been shown in normal kidney, and its over-activation has been demonstrated in several renal diseases. The extracellular signal-regulated protein kinases (ERK 1,2) signalling pathway is the first described MAPK signaling. Intensive investigations have demonstrated that it participates in the regulation of ureteric bud branching, a fundamental process in establishing final nephron number; in addition, it is also involved in the differentiation of the nephrogenic mesenchyme, indicating a key role in mammalian kidney embryonic development. In the present manuscript, we show that ERK1,2 signalling mediates several cellular functions also in mature kidney, describing its role along the nephron and demonstrating whether it contributes to the regulation of ion channels and transporters implicated in acid-base and electrolytes homeostasis.


Assuntos
Equilíbrio Ácido-Base , Eletrólitos/metabolismo , Sistema de Sinalização das MAP Quinases , Néfrons/metabolismo , Equilíbrio Hidroeletrolítico , Animais , Suscetibilidade a Doenças , Humanos , Túbulos Renais Coletores/metabolismo , Túbulos Renais Distais/metabolismo , Túbulos Renais Proximais/metabolismo , Alça do Néfron/metabolismo
15.
Hypertension ; 74(3): 509-517, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31352823

RESUMO

We have previously shown that podocyte injury increases the glomerular filtration of liver-derived Agt (angiotensinogen) and the generation of intrarenal Ang II (angiotensin II) and that the filtered Agt is reabsorbed by proximal tubules in a manner dependent on megalin. In the present study, we aimed to study the role of megalin in the generation of renal Ang II and sodium handling during nephrotic syndrome. We generated proximal tubule-specific megalin KO (knockout) mice and crossed these animals with NEP25 mice, in which podocyte-specific injury can be induced by injection of the immunotoxin LMB2. Without podocyte injury, renal Agt staining was markedly diminished and urinary Agt increased in KO mice. However, renal Ang II was similar between KO and control mice on average: 117 (95% CI, 101-134) versus 101 (95% CI, 68-133) fmol/g tissue. We next tested the effect of megalin KO on intrarenal Ang II generation with podocyte injury. Control NEP25 mice showed markedly increased renal Agt staining and renal Ang II levels: 450 (336-565) fmol/g tissue. Megalin KO/NEP25 mice showed markedly diminished Agt reabsorption and attenuated renal Ang II: 199 (156-242) fmol/g tissue (P<0.001). Compared with control NEP25 mice, megalin KO/NEP25 mice excreted 5-fold more sodium in the urine. Western blot analysis showed that megalin KO decreased NHE3 and the cleaved α and γ forms of Epithelial Na Channel. These data indicate that Agt reabsorbed by proximal tubules via megalin in nephrotic syndrome is converted to Ang II, which may contribute to sodium retention and edema formation by activating NHE3 and Epithelial Na Channel.


Assuntos
Angiotensina II/metabolismo , Hipernatremia/fisiopatologia , Túbulos Renais Proximais/metabolismo , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Síndrome Nefrótica/metabolismo , Síndrome Nefrótica/patologia , Animais , Biópsia por Agulha , Edema/etiologia , Edema/fisiopatologia , Hipernatremia/metabolismo , Imuno-Histoquímica , Túbulos Renais Proximais/patologia , Masculino , Camundongos , Camundongos Knockout , Podócitos/citologia , Podócitos/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Sistema Renina-Angiotensina , Fatores de Risco , Sensibilidade e Especificidade , Sódio/metabolismo , Urinálise
16.
Hypertension ; 74(3): 526-535, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31352824

RESUMO

The present study directly tested the hypothesis that the NHE3 (Na+/H+ exchanger 3) in the proximal tubules of the kidney is required for the development of Ang II (angiotensin II)-induced hypertension using PT-Nhe3-/- (proximal tubule-specific NHE3 knockout) mice. Specifically, PT-Nhe3-/- mice were generated using the SGLT2-Cre/Nhe3loxlox approach, whereas Ang II-induced hypertension was studied in 12 groups (n=5-12 per group) of adult male and female wild-type (WT) and PT-Nhe3-/- mice. Under basal conditions, systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure were significantly lower in male and female PT-Nhe3-/- than WT mice (P<0.01). A high pressor, 1.5 mg/kg per day, intraperitoneal or a slow pressor dose of Ang II, 0.5 mg/kg per day, intraperitoneal for 2 weeks significantly increased systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure in male and female WT mice (P<0.01), but the hypertensive response to Ang II was markedly attenuated in male and female PT-Nhe3-/- mice (P<0.01). Ang II impaired the pressure-natriuresis response in WT mice, whereas proximal tubule-specific deletion of NHE3 improved the pressure-natriuresis response in Ang II-infused PT-Nhe3-/- mice (P<0.01). AT1 receptor blocker losartan completely blocked Ang II-induced hypertension in both WT and PT-Nhe3-/- mice (P<0.01). However, inhibition of nitric oxide synthase with L-NG-Nitroarginine methyl ester had no effect on Ang II-induced hypertension in WT or PT-Nhe3-/- mice (not significant). Furthermore, Ang II-induced hypertension was significantly attenuated by an orally absorbable NHE3 inhibitor AVE0657. In conclusion, NHE3 in the proximal tubules of the kidney may be a therapeutical target in hypertension induced by Ang II or with increased NHE3 expression in the proximal tubules.


Assuntos
Angiotensina II/farmacologia , Túbulos Renais Proximais/metabolismo , Losartan/administração & dosagem , Receptor Tipo 1 de Angiotensina/metabolismo , Trocador 3 de Sódio-Hidrogênio/genética , Animais , Modelos Animais de Doenças , Feminino , Hipertensão/induzido quimicamente , Hipertensão/tratamento farmacológico , Hipertensão/fisiopatologia , Injeções Intraperitoneais , Túbulos Renais Proximais/patologia , Masculino , Camundongos , Camundongos Knockout , Distribuição Aleatória , Valores de Referência , Trocadores de Sódio-Hidrogênio/metabolismo , Resultado do Tratamento
17.
Int J Mol Sci ; 20(14)2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295865

RESUMO

G-protein-coupled receptor 40 (GPR40) has an anti-apoptotic effect in pancreatic ß-cells. However, its role in renal tubular cell apoptosis remains unclear. To explore the role of GPR40 in renal tubular apoptosis, a two-week unilateral ureteral obstruction (UUO) mouse model was used. The protein expression of GPR40 was decreased, while the Bax/Bcl-2 protein expression ratio, the expression of tumor necrosis factor (TNF)-α mRNA, and angiotensin II type 1 receptor (AT1R) protein were increased in mice with UUO. In vitro, pretreatment of rat proximal tubular (NRK52E) cells with GW9508, a GPR40 agonist, attenuated the decreased cell viability, increased the Bax/Bcl-2 protein expression ratio, increased protein expression of cleaved caspase-3 and activated the nuclear translocation of nuclear factor-κB (NF-κB) p65 subunit induced by TNF-α treatment. TNF-α treatment significantly increased the expression of AT1R protein and the generation of reactive oxygen species (ROS), whereas GW9508 treatment markedly reversed these effects. Pretreatment with GW1100, a GPR40 antagonist, or silencing of GPR40 in NRK52E cells promoted the increased expression of the cleaved caspase-3 protein by TNF-α treatment. Our results demonstrate that decreased expression of GPR40 is associated with apoptosis via TNF-α and AT1R in the ureteral obstructed kidney. The activation of GPR40 attenuates TNF-α-induced apoptosis by inhibiting AT1R expression and ROS generation through regulation of the NF-κB signaling pathway.


Assuntos
Lesão Renal Aguda/metabolismo , Apoptose/efeitos dos fármacos , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Lesão Renal Aguda/tratamento farmacológico , Lesão Renal Aguda/etiologia , Lesão Renal Aguda/patologia , Animais , Apoptose/genética , Biomarcadores , Modelos Animais de Doenças , Imunofluorescência , Expressão Gênica , Imuno-Histoquímica , Túbulos Renais Proximais/patologia , Masculino , Ratos , Receptores Acoplados a Proteínas-G/agonistas , Receptores Acoplados a Proteínas-G/genética , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia , Obstrução Ureteral/complicações , Obstrução Ureteral/genética , Obstrução Ureteral/metabolismo
18.
Int J Mol Sci ; 20(13)2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31262033

RESUMO

A number of signal transduction pathways are activated during Acute Kidney Injury (AKI). Of particular interest is the Salt Inducible Kinase (SIK) signaling network, and its effects on the Renal Proximal Tubule (RPT), one of the primary targets of injury in AKI. The SIK1 network is activated in the RPT following an increase in intracellular Na+ (Na+in), resulting in an increase in Na,K-ATPase activity, in addition to the phosphorylation of Class IIa Histone Deacetylases (HDACs). In addition, activated SIKs repress transcriptional regulation mediated by the interaction between cAMP Regulatory Element Binding Protein (CREB) and CREB Regulated Transcriptional Coactivators (CRTCs). Through their transcriptional effects, members of the SIK family regulate a number of metabolic processes, including such cellular processes regulated during AKI as fatty acid metabolism and mitochondrial biogenesis. SIKs are involved in regulating a number of other cellular events which occur during AKI, including apoptosis, the Epithelial to Mesenchymal Transition (EMT), and cell division. Recently, the different SIK kinase isoforms have emerged as promising drug targets, more than 20 new SIK2 inhibitors and activators having been identified by MALDI-TOF screening assays. Their implementation in the future should prove to be important in such renal disease states as AKI.


Assuntos
Lesão Renal Aguda/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Lesão Renal Aguda/genética , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Humanos , Túbulos Renais Proximais/metabolismo , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Sódio/metabolismo
19.
J Diabetes Res ; 2019: 8512028, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31355294

RESUMO

Aim: To explore the role of group 2 innate lymphoid cells (ILC2s) in the pathogenesis of renal fibrosis in diabetic kidney disease (DKD). Methods: The proportion of ILC2s and the levels of Th2 cytokines (IL-4, IL-5, and IL-13) in the peripheral blood of normal control subjects (NC) or patients with type 2 diabetes mellitus (DM), early diabetic kidney disease (DKD1), or late diabetic kidney disease (DKD2) were analyzed by flow cytometry and ELISA. The expression of transforming growth factor-ß1 (TGF-ß1), fibronectin (FN), collagen1, IL-4Rα, and IL-13Rα1 in renal tubular epithelial cells (HK-2) induced by IL-4, IL-13, or high glucose was analyzed by ELISA or qPCR. Results: The proportion of ILC2s and the levels of IL-4, IL-5, and IL-13 were significantly increased in DKD patients and were positively correlated with the severity of DKD (P < 0.05). The expression of TGF-ß1, FN, and collagen1 was significantly upregulated in HK-2 cells induced by IL-4 or IL-13 (P < 0.05). Moreover, the IL-4Rα and IL-13Rα1 mRNA in HK2 cells were increased followed by high glucose alone or combined with IL-4 or IL-13, but the differences were not statistically significant (P > 0.05). However, compared with high-glucose stimulation alone, the expression of TGF-ß1, FN, and collagen1 was significantly increased in HK-2 cells induced by high glucose combined with IL-4 or IL-13 (P < 0.05). Conclusions: ILC2s may participate in renal fibrosis in DKD partly via TGF-ß1 signal pathway.


Assuntos
Diabetes Mellitus Tipo 2/sangue , Nefropatias Diabéticas/sangue , Rim/patologia , Linfócitos/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta1/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Linhagem Celular , Colágeno/metabolismo , Diabetes Mellitus Tipo 2/complicações , Feminino , Fibrose , Humanos , Imunidade Inata/efeitos dos fármacos , Interleucina-13/sangue , Subunidade alfa1 de Receptor de Interleucina-13/sangue , Interleucina-4/sangue , Subunidade alfa de Receptor de Interleucina-4/sangue , Interleucina-5/sangue , Túbulos Renais Proximais/metabolismo , Masculino , Pessoa de Meia-Idade , Células Th2/citologia
20.
J Photochem Photobiol B ; 198: 111560, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31336216

RESUMO

Previous studies revealed significant impact on cancer cell by mid-infrared (MIR) radiation. However, the effects of narrow band MIR on immune reaction and infectious disease are still unknown. In this study, an enhanced innate immune response was observed through the interaction between Leptospiral outer membrane protein (LipL32) and toll-like receptor 2 (TLR2). Thereafter, human kidney proximal tubular cells (HK-2 cells) initiated a serial reaction of enhanced MCP-1 production. The 6 µm narrow bandwidth light source emitted by waveguide thermal emitter (WTE) was applied to induce carbonyl group (CO bond) stretching vibration during the stage of antigen-receptor complex formation. The amount of MCP-1 gene expression had 2.5 folds increase after narrow band MIR illumination comparing to non-MIR illumination at low dose LipL32 condition. Besides, both ELISA and confocal microscopy results also revealed that the chemokine concentration increased significantly after narrow band MIR illumination either at low or high concentration of LipL32. Furthermore, a specific phenomenon that narrow band MIR can amplify the signal of weak immune response by enhancing sensitivity of the interaction between antigen and receptor was observed. This study exhibits clear evidence that the narrow band MIR exposure can modulate the early immune response of infectious disease and play a potential role to develop host-directed therapy in the future.


Assuntos
Proteínas da Membrana Bacteriana Externa/farmacologia , Raios Infravermelhos , Lipoproteínas/farmacologia , Proteínas da Membrana Bacteriana Externa/imunologia , Linhagem Celular , Sobrevivência Celular/efeitos da radiação , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Leptospira/metabolismo , Lipoproteínas/imunologia
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