RESUMO
Acute kidney injury (AKI) is a common and devastating pathologic condition, associated with considerable high morbidity and mortality. Although significant breakthroughs have been made in recent years, to this day no effective pharmacological therapies for its treatment exist. AKI is known to be connected with intrarenal and systemic inflammation. The innate immune system plays an important role as the first defense response mechanism to tissue injury. Toll-like receptor 4 (TLR4) is a well-characterized pattern recognition receptor, and increasing evidence has shown that TLR4 mediated inflammatory response, plays a pivotal role in the pathogenesis of acute kidney injury. Pathogen-associated molecular patterns (PAMPS), which are the conserved microbial motifs, are sensed by these receptors. Endogenous molecules generated during tissue injury, and labeled as damage-associated molecular pattern molecules (DAMPs), also activate pattern recognition receptors, thereby offering an understanding of sterile types of inflammation. Excessive, uncontrolled and/or sustained activation of TLR4, may lead to a chronic inflammatory state. In this review we describe the role of TLR4, its endogenous ligands and activation in the inflammatory response to ischemic/reperfusion-induced AKI and sepsis-associated AKI. The potential regeneration signaling patterns of TLR4 in acute kidney injury, are also discussed.
Assuntos
Injúria Renal Aguda , Receptor 4 Toll-Like , Humanos , Injúria Renal Aguda/patologia , Inflamação/patologia , Receptores de Reconhecimento de Padrão/fisiologia , Transdução de Sinais , Rim/patologiaRESUMO
Angiotensin II exerts a cardinal role in the pathogenesis of hypertension and renal injury via action of angiotensin II type 1 (AT1) receptors. Local renin-angiotensin system (RAS) activity is essential for the mechanisms mediating pathophysiological functions. Proximal tubular angiotensinogen and tubular AT1 receptors are augmented by intrarenal angiotensin II. Caveolin 1 plays an important role as a regulatory molecule for the compartmentalization of redox signaling events through angiotensin II-induced NADPH oxidase activation in the kidney. A role for the renin-angiotensin system in the development and/or maintenance of hypertension has been demonstrated in spontaneously hypertensive rats (SHRs). Many effects of angiotensin II are dependent on the AT1 stimulation of reactive oxygen species (ROS) production by NADPH oxidase. Angiotensin II upregulation stimulates oxidative stress in proximal tubules from SHR. The NADPH oxidase 4 (Nox4) is abundantly expressed in kidney proximal tubule cells. Induction of the stress response includes synthesis of heat shock protein 70, a molecular chaperone that has a critical role in the recovery of cells from stress and in cytoprotection, guarding cells from subsequent insults. HSP70 chaperones function in part by driving the molecular triage decision, which determines whether proteins enter the productive folding pathway or result in client substrate ubiquitination and proteasomal degradation. This review examines regulation of losartan-mediated antioxidative stress responses by the chaperone HSP70 in proximal tubule cells of spontaneously hypertensive rats.
Assuntos
Injúria Renal Aguda/tratamento farmacológico , Antioxidantes/farmacologia , Proteínas de Choque Térmico HSP70/metabolismo , Hipertensão/tratamento farmacológico , Losartan/farmacologia , Angiotensina II/metabolismo , Animais , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , NADPH Oxidase 4/metabolismo , Ratos , Ratos Endogâmicos SHRRESUMO
BACKGROUND: The inflammatory response of the host to Shiga toxin and/or lipopolysaccharide (LPS) of Escherichia coli (E. coli) is included in (HUS). The TLR4-LPS complex is internalized and TLR4 induced inflammatory signaling is stopped by targeting the complex for degradation. Rab7b, a small guanosine triphosphatase (GTPase) expressed in monocytes, regulates the later stages of the endocytic pathway. OBJECTIVE: we studied the Rab7b participation on the TLR4 endocytic pathway and its effect on monocyte cytokine production along the acute course of pediatric Shiga toxin-associated HUS. METHODS AND RESULTS: Monocytes were identified according to their positivity in CD14 expression. Surface TLR4 expression in monocytes from 18 HUS patients significantly increased by day 1 to 6, showing the highest increase on day 4 compared to monocytes of 10 healthy children. Significant higher surface TLR4 expression was accompanied by increased proinflammatory intracellular cytokines, tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6). In contrast, after these time points, surface TLR4 expression and intracellular TNF-α levels, returned to near control levels after 10â¯days. Furthermore, confocal immunofluorescence microscopy proved colocalization of increased intracellular TLR4/Rab7b determined by Pearson's coefficient in monocytes from HUS patients from day 1 on the highest colocalization of both proteins by day 4. Decreased TLR4/Rab7b colocalization was shown 10â¯days after HUS onset. CONCLUSION: The colocalization of TLR4 and Rab7b allows us to suggest Rab7b participation in the control of the TLR4 endocytic pathway in HUS patient monocytes. A consequential fall in cytokine production throughout the early follow up of HUS is demonstrated.
Assuntos
Endocitose , Síndrome Hemolítico-Urêmica/metabolismo , Síndrome Hemolítico-Urêmica/patologia , Toxina Shiga/metabolismo , Receptor 4 Toll-Like/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Doença Aguda , Criança , Pré-Escolar , Citocinas/sangue , Seguimentos , Síndrome Hemolítico-Urêmica/sangue , Humanos , Lactente , Receptores de Lipopolissacarídeos/metabolismo , Monócitos/metabolismo , proteínas de unión al GTP Rab7RESUMO
A series of signaling cascades are activated after angiotensin II binds to angiotensin II type I receptor (AT1R), a peptide that is an important mediator of oxidative stress. Hsp70 regulates a diverse set of signaling pathways through interactions with proteins. Here, we tested the hypothesis of angiotensin II AT1R inhibition effect on Hsp70 interaction with Nox4/p22phox complex and Hsp70 leading to actin cytoskeleton modulation in spontaneously hypertensive rats (SHR) vascular smooth muscle cells (VSMCs). SHR and Wistar-Kyotto rats (VSMCs from 8 to 10 weeks) were stimulated with angiotensin II (100 nmol/L) for 15 min (AII), treated with losartan (100 nmol/L) for 90 min (L), and with losartan for 90 min plus angiotensin in the last 15 min (L + AII). Whereas SHR VSMCs exposure to angiotensin II overexpressed AT1R and Nox4 nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase and slightly downregulated caveolin-1 expression, losartan decreased AT1R protein levels and increased caveolin-1 and Hsp70 expression in SHR VSMC membranes. Immunoprecipitation and immunofluorescence confocal microscopy proved interaction and colocalization of membrane translocated Hsp70 and Nox4/p22phox. Increased levels of Hsp70 contrast with the decreased immunoprecipitation of Nox4/p22phox and RhoA in membranes from SHR VSMCs (L) vs SHR VSMCs (AII). Hsp72 depletion resulted in higher Nox4 expression and increased NADPH oxidase activity in VSMCs (L + AII) from SHR when contrasted with nontransfected VSMCs (L + AII). After Hsp72 knockdown in SHR VSMCs, losartan could not impair angiotensin II-enhanced stress fiber formation and focal adhesion assembly. In conclusion, our data showing a negative regulation of Hsp70 on Nox4/p22phox demonstrates a possible mechanism in explaining the antioxidative function joined to cytoskeletal integrity modulation within the effects of losartan in VSMCs from SHR.
Assuntos
Anti-Hipertensivos/farmacologia , Proteínas de Choque Térmico HSP70/metabolismo , Losartan/farmacologia , Músculo Liso Vascular/efeitos dos fármacos , NADPH Oxidases/metabolismo , Angiotensina II/farmacologia , Animais , Caveolina 1/metabolismo , Células Cultivadas , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Proteínas de Choque Térmico HSP72/antagonistas & inibidores , Proteínas de Choque Térmico HSP72/genética , Proteínas de Choque Térmico HSP72/metabolismo , Masculino , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , NADPH Oxidase 4 , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Ratos Wistar , Receptor Tipo 1 de Angiotensina/química , Receptor Tipo 1 de Angiotensina/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismoRESUMO
Evidence suggesting that statins may contribute to renoprotection has been provided in experimental and clinical studies. Statins restore endothelial nitric oxide (NO) levels by mechanisms including up-regulation of endothelial NO synthase (eNOS) expression. Caveolin-1/eNOS interaction is essential preventing inadequate NO levels. Here, we evaluated whether caveolin-1 associated with eNOS/Hsp70 expression may be involved in the mechanism by which rosuvastatin exerts tubulointerstitial fibrosis protection in neonatal unilateral ureteral obstruction (UUO). Neonatal rats subjected to UUO within 2 days of birth and controls were treated daily with vehicle or rosuvastatin (10 mg/kg/day) by oral gavage for 14 days. After UUO, morphometric evaluation of interstitial fibrosis showed increased interstitial volume (Vv) associated with reduced NO availability, increased mRNA and protein caveolin-1 expression as well as downregulation eNOS and heat shock protein 70 (Hsp70) expression. Conversely, rosuvastatin treatment attenuated the fibrotic response linked to high NO availability, decreased mRNA and protein caveolin-1 expression, and marked upregulation of eNOS and Hsp70 expression at transcriptional and posttranscriptional levels. Moreover, protein-protein interactions determined by immunoprecipitation and by immunofluorescence co-localization have shown decreased caveolin-1/eNOS as well as increased Hsp70/eNOS interaction, after rosuvastatin treatment. A dose dependent effect of rosuvastatin on decreased caveolin-1 expression was shown in control cortex. In conclusion, our data suggest that statins contribute to the protection against tubulointerstitial fibrosis injury in neonatal early kidney obstruction by increased NO availability, involving interaction of up-regulated eNOS/Hsp70 and down-regulated caveolin-1.
Assuntos
Caveolina 1/metabolismo , Fluorbenzenos/farmacologia , Proteínas de Choque Térmico HSP70/metabolismo , Nefropatias/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Substâncias Protetoras/farmacologia , Pirimidinas/farmacologia , Sulfonamidas/farmacologia , Animais , Animais Recém-Nascidos , Feminino , Humanos , Nefropatias/tratamento farmacológico , Masculino , Óxido Nítrico/metabolismo , Ratos , Ratos Endogâmicos WKY , Rosuvastatina Cálcica , Obstrução UreteralRESUMO
There is growing evidence that statins may exert renoprotective effects beyond cholesterol reduction. The cholesterol-independent or "pleiotropic" effects of statins include the upregulation of endothelial nitric oxide synthase (eNOS). Here we determined whether eNOS associated with Hsp70 expression is involved in rosuvastatin resistance to obstruction-induced oxidative stress and cell death. Neonatal rats subjected to unilateral ureteral obstruction (UUO) within two days of birth and controls were treated daily with vehicle or rosuvastatin (10 mg/kg/day) for 14 days. Decreased endogenous nitric oxide (NO) and lower mRNA and protein eNOS expression associated with downregulation of heat shock factor 1 (Hsf1) mRNA and Hsp70 protein levels were observed in the obstructed kidney cortex. Increased nicotinamide adenine dinucleotide phosphate (NADHP) oxidase activity and apoptosis induction, regulated by mitochondrial signal pathway through an increased pro-apoptotic Bax/BcL(2) ratio and caspase 3 activity, were demonstrated. Conversely, in cortex membrane fractions from rosuvastatin-treated UUO rats, marked upregulation of eNOS expression at transcriptional and posttranscriptional levels linked to increased Hsf1 mRNA expression and enhanced mRNA and protein Hsp70 expression, were observed. Consequently, there was an absence of apoptotic response and transiently decreased NADPH oxidase activity. In addition, interaction between eNOS and Hsp70 was determined by communoprecipitation in cortex membrane fractions, showing an increased ratio of both proteins, after rosuvastatin treatment in obstructed kidney. In summary, our data demonstrate that the effect of rosuvastatin on eNOS interacting with Hsp70, results in the capacity of both to prevent mitochondrial apoptotic pathway and oxidative stress in neonatal early kidney obstruction.
Assuntos
Fluorbenzenos/farmacologia , Proteínas de Choque Térmico HSP70/metabolismo , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Nefropatias/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Pirimidinas/farmacologia , Sulfonamidas/farmacologia , Obstrução Ureteral/metabolismo , Animais , Animais Recém-Nascidos , Apoptose/efeitos dos fármacos , Caspase 3/análise , Caspase 3/metabolismo , Citoproteção , Feminino , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Nefropatias/etiologia , Nefropatias/patologia , Masculino , NADPH Oxidases/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos WKY , Rosuvastatina Cálcica , Superóxido Dismutase/metabolismo , Obstrução Ureteral/complicações , Proteína X Associada a bcl-2/metabolismoRESUMO
Wilms tumor gene 1 (wt-1), a key regulator of mesenchymal-epithelial transformation, is downregulated during congenital obstructive nephropathy, leading to apoptosis. There is a functional interaction between WT-1 and inducible nitric oxide synthase (iNOS). In this regard, we reported that after neonatal unilateral ureteral obstruction, rosuvastatin prevents apoptosis through an increase in nitric oxide bioavailability, which in turn is linked to higher Hsp70 expression. Hence, the goal of this study was to determine whether a nitric oxide/Hsp70 interaction is involved in changes in WT-1 mRNA expression after ureteral obstruction. Neonatal rats submitted to experimental ureteral obstruction were treated with either vehicle or rosuvastatin for 14 days. Decreased nitric oxide and iNOS/Hsp70 expression associated wit h WT-1 low expression was shown in obstructed kidneys. Apoptosis was induced and it was associated with an increased Bax/BcL2 ratio. Conversely, iNOS/Hsp70 upregulation and an increased WT-1 mRNA expression, without an apoptotic response, were observed in the cortex of obstructed kidneys of rosuvastatin-treated rats. Nitric oxide also modulated Hsp70 and WT-1 mRNA expression in MDCK cells. Finally, in vivo experiments with nitric oxide modulators support our hypothesis that WT-1 mRNA expression is associated with nitric oxide level. Results suggest that rosuvastatin may modulate WT-1 mRNA expression through renal nitric oxide bioavailability, preventing neonatal obstruction-induced apoptosis associated with Hsp70 interaction.
Assuntos
Masculino , Animais , Feminino , Recém-Nascido , Cães , Ratos , Apoptose , Apoptose/fisiologia , Linhagem Celular , Células Epiteliais/citologia , Células Epiteliais , Células Epiteliais/fisiologia , Modelos Animais de Doenças , Inibidores Enzimáticos/farmacologia , Luminol/análogos & derivados , Luminol/farmacologia , Fluorbenzenos/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , /genética , /metabolismo , Rim/citologiaRESUMO
Wilms tumor gene 1 (wt-1), a key regulator of mesenchymal-epithelial transformation, is downregulated during congenital obstructive nephropathy, leading to apoptosis. There is a functional interaction between WT-1 and inducible nitric oxide synthase (iNOS). In this regard, we reported that after neonatal unilateral ureteral obstruction, rosuvastatin prevents apoptosis through an increase in nitric oxide bioavailability, which in turn is linked to higher Hsp70 expression. Hence, the goal of this study was to determine whether a nitric oxide/Hsp70 interaction is involved in changes in WT-1 mRNA expression after ureteral obstruction. Neonatal rats submitted to experimental ureteral obstruction were treated with either vehicle or rosuvastatin for 14 days. Decreased nitric oxide and iNOS/Hsp70 expression associated wit h WT-1 low expression was shown in obstructed kidneys. Apoptosis was induced and it was associated with an increased Bax/BcL2 ratio. Conversely, iNOS/Hsp70 upregulation and an increased WT-1 mRNA expression, without an apoptotic response, were observed in the cortex of obstructed kidneys of rosuvastatin-treated rats. Nitric oxide also modulated Hsp70 and WT-1 mRNA expression in MDCK cells. Finally, in vivo experiments with nitric oxide modulators support our hypothesis that WT-1 mRNA expression is associated with nitric oxide level. Results suggest that rosuvastatin may modulate WT-1 mRNA expression through renal nitric oxide bioavailability, preventing neonatal obstruction-induced apoptosis associated with Hsp70 interaction.(AU)
Assuntos
Masculino , Animais , Feminino , Recém-Nascido , Cães , Ratos , Apoptose , Apoptose/fisiologia , Linhagem Celular , Modelos Animais de Doenças , Inibidores Enzimáticos/farmacologia , Células Epiteliais/citologia , Células Epiteliais , Células Epiteliais/fisiologia , Luminol/análogos & derivados , Luminol/farmacologia , Fluorbenzenos/farmacologia , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Rim/citologiaRESUMO
Wilms tumor gene 1 (wt-1), a key regulator of mesenchymal-epithelial transformation, is downregulated during congenital obstructive nephropathy, leading to apoptosis. There is a functional interaction between WT-1 and inducible nitric oxide synthase (iNOS). In this regard, we reported that after neonatal unilateral ureteral obstruction, rosuvastatin prevents apoptosis through an increase in nitric oxide bioavailability, which in turn is linked to higher Hsp70 expression. Hence, the goal of this study was to determine whether a nitric oxide/Hsp70 interaction is involved in changes in WT-1 mRNA expression after ureteral obstruction. Neonatal rats submitted to experimental ureteral obstruction were treated with either vehicle or rosuvastatin for 14 days. Decreased nitric oxide and iNOS/Hsp70 expression associated with WT-1 low expression was shown in obstructed kidneys. Apoptosis was induced and it was associated with an increased Bax/BcL2 ratio. Conversely, iNOS/Hsp70 upregulation and an increased WT-1 mRNA expression, without an apoptotic response, were observed in the cortex of obstructed kidneys of rosuvastatin-treated rats. Nitric oxide also modulated Hsp70 and WT-1 mRNA expression in MDCK cells. Finally, in vivo experiments with nitric oxide modulators support our hypothesis that WT-1 mRNA expression is associated with nitric oxide level. Results suggest that rosuvastatin may modulate WT-1 mRNA expression through renal nitric oxide bioavailability, preventing neonatal obstruction-induced apoptosis associated with Hsp70 interaction.