scholarly journals Proximal Tubular Transcription Factors in Acute Kidney Injury: Recent Advances

Nephron ◽  
2020 ◽  
Vol 144 (12) ◽  
pp. 613-615
Author(s):  
Sian E. Piret ◽  
Sandeep K. Mallipattu
Keyword(s):  
Acute Kidney Injury ◽  
Transcription Factors ◽  
Cell Biology ◽  
Kidney Injury ◽  
Mechanistic Studies ◽  
Proximal Tubular ◽  
Pt Cell ◽  
Transcriptomic Changes ◽  
Major Target ◽  
Novel Therapeutic

The proximal tubule (PT) is a major target in acute kidney injury (AKI), leading to profound changes in PT cell biology. Amongst the genes with early and robust changes in expression are many transcription factors (TFs), which themselves account for other transcriptomic changes. Potentially important TFs are being revealed in large sequencing datasets; however, to understand whether these TFs account for adaptive or maladaptive changes requires further mechanistic studies, which may reveal novel therapeutic targets. This mini review will highlight the identification and biology of 3 novel TFs in AKI: <i>Sox9</i>, <i>Foxm1</i>, and <i>Foxo3</i>.

scholarly journals Proximal tubule-specific overexpression of netrin-1 suppresses acute kidney injury-induced interstitial fibrosis and glomerulosclerosis through suppression of IL-6/STAT3 signaling

2013 ◽  
Vol 304 (8) ◽  
pp. F1054-F1065 ◽  
Author(s):  
Punithavathi Ranganathan ◽  
Calpurnia Jayakumar ◽  
Ganesan Ramesh
Keyword(s):  
Acute Kidney Injury ◽  
Epithelial Cells ◽  
Interstitial Fibrosis ◽  
Kidney Injury ◽  
Transgenic Animals ◽  
Acute Injury ◽  
Tubular Epithelial Cells ◽  
Wild Type ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular

Acute kidney injury-induced organ fibrosis is recognized as a major risk factor for the development of chronic kidney disease, which remains one of the leading causes of death in the developed world. However, knowledge on molecules that may suppress the fibrogenic response after injury is lacking. In ischemic models of acute kidney injury, we demonstrate a new function of netrin-1 in regulating interstitial fibrosis. Acute injury was promptly followed by a rise in serum creatinine in both wild-type and netrin-1 transgenic animals. However, the wild-type showed a slow recovery of kidney function compared with netrin-1 transgenic animals and reached baseline by 3 wk. Histological examination showed increased infiltration of interstitial macrophages, extensive fibrosis, reduction of capillary density, and glomerulosclerosis. Collagen IV and α-smooth muscle actin expression was absent in sham-operated kidneys; however, their expression was significantly increased at 2 wk and peaked at 3 wk after reperfusion. These changes were reduced in the transgenic mouse kidney, which overexpresses netrin-1 in proximal tubular epithelial cells. Fibrosis was associated with increased expression of IL-6 and extensive and chronic activation of STAT3. Administration of IL-6 exacerbated fibrosis in vivo in wild-type, but not in netrin-1 transgenic mice kidney and increased collagen I expression and STAT3 activation in vitro in renal epithelial cells subjected to hypoxia-reoxygenation, which was suppressed by netrin-1. Our data suggest that proximal tubular epithelial cells may play a prominent role in interstitial fibrosis and that netrin-1 could be a useful therapeutic agent for treating kidney fibrosis.

scholarly journals Renalase and Biomarkers of Contrast-Induced Acute Kidney Injury

2015 ◽  
Vol 6 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Maciej T. Wybraniec ◽  
Katarzyna Mizia-Stec
Keyword(s):  
Acute Kidney Injury ◽  
Renal Injury ◽  
Amine Oxidase ◽  
Kidney Injury ◽  
Cardiorenal Syndrome ◽  
Creatinine Concentration ◽  
Invasive Cardiology ◽  
Proximal Tubular ◽  
Novel Biomarkers

Background: Contrast-induced acute kidney injury (CI-AKI) remains one of the crucial issues related to the development of invasive cardiology. The massive use of contrast media exposes patients to a great risk of contrast-induced nephropathy and chronic kidney disease development, and increases morbidity and mortality rates. The serum creatinine concentration does not allow for a timely and accurate CI-AKI diagnosis; hence numerous other biomarkers of renal injury have been proposed. Renalase, a novel catecholamine-metabolizing amine oxidase, is synthesized mainly in proximal tubular cells and secreted into urine and blood. It is primarily engaged in the degradation of circulating catecholamines. Notwithstanding its key role in blood pressure regulation, renalase remains a potential CI-AKI biomarker, which was shown to be markedly downregulated in the aftermath of renal injury. In this sense, renalase appears to be the first CI-AKI marker revealing an actual loss of renal function and indicating disease severity. Summary: The purpose of this review is to summarize the contemporary knowledge about the application of novel biomarkers of CI-AKI and to highlight the potential role of renalase as a functional marker of contrast-induced renal injury. Key Messages: Renalase may constitute a missing biochemical link in the mutual interplay between kidney and cardiac pathology known as the cardiorenal syndrome.

scholarly journals Canagliflozin protects against cisplatin-induced acute kidney injury by AMPK-mediated autophagy in renal proximal tubular cells

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Cheol Ho Park ◽  
Bin Lee ◽  
Myeonggil Han ◽  
Woo Joong Rhee ◽  
Man Sup Kwak ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Protective Effect ◽  
Kidney Injury ◽  
Proximal Tubular Cells ◽  
Cell Viability Assay ◽  
Tubular Cells ◽  
Compound C ◽  
Proximal Tubular ◽  
Renal Proximal Tubular Cells ◽  
Renal Proximal Tubular

AbstractSodium-glucose cotransporter 2 inhibitors, which are recently introduced as glucose-lowering agents, improve cardiovascular and renal outcomes in patients with diabetes mellitus. These drugs also have beneficial effects in various kidney disease models. However, the effect of SGLT2 inhibitors on cisplatin-induced acute kidney injury (AKI) and their mechanism of action need to be elucidated. In this study, we investigated whether canagliflozin protects against cisplatin-induced AKI, depending on adenosine monophosphate-activated protein kinase (AMPK) activation and following induction of autophagy. In the experiments using the HK-2 cell line, cell viability assay and molecular analysis revealed that canagliflozin protected renal proximal tubular cells from cisplatin, whereas addition of chloroquine or compound C abolished the protective effect of canagliflozin. In the mouse model of cisplatin-induced AKI, canagliflozin protected mice from cisplatin-induced AKI. However, treatment with chloroquine or compound C in addition to administration of cisplatin and canagliflozin eliminated the protective effect of canagliflozin. Collectively, these findings indicate that canagliflozin protects against cisplatin-induced AKI by activating AMPK and autophagy in renal proximal tubular cells.

scholarly journals P0511ENHANCER AND SUPER-ENHANCER DYNAMICS IN REPAIR AFTER ISCHEMIC ACUTE KIDNEY INJURY

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Julia Wilflingseder ◽  
Michaela Willi ◽  
Hye Kyung Lee ◽  
Hannes Olauson ◽  
Jakub Jankowsky ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Transcription Factors ◽  
Small Molecule ◽  
Ischemia Reperfusion Injury ◽  
Specific Binding ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Kidney Cortex ◽  
Super Enhancer

Abstract Background and Aims The endogenous repair process of the mammalian kidney allows rapid recovery after acute kidney injury (AKI) through robust proliferation of tubular epithelial cells. There is currently limited understanding of which transcriptional regulators activate these repair programs and how transcriptional dysregulation leads to maladaptive repair. Here we investigate the existence of enhancer dynamics in the regenerating mouse kidney. Method RNA-seq and ChIP-seq (H3K27ac, H3K4m3, BRD4, POL2 and selected transcription factors) were performed on samples from repairing kidney cortex 2 days after ischemia/reperfusion injury (IRI) to identify activated genes, transcription factors, enhancer and super-enhancers associated with kidney repair. Further we investigated the role of super-enhancer activation in kidney repair through pharmacological BET inhibition using the small molecule JQ1 in vitro and in acute kidney injury models in vivo. Results Response to kidney injury leads to genome-wide alteration in enhancer repertoire in-vivo. We identified 16,781 enhancer sites (H3K27ac and BRD4 positive, H3K4me3 negative binding) active in SHAM and IRI samples; 6,512 lost and 9,774 gained after IRI. The lost and gained enhancer sites can be annotated to 62% and 63% of down- and up-regulated transcripts at day 2 after kidney injury, respectively. Super-enhancer analysis revealed 164 lost and 216 gained super-enhancer sites at IRI day 2. 385 super-enhancers maintain activity before and after injury. ChIP-seq profiles of selected transcription factors based on motif analysis show specific binding at corresponding enhancer sites. We observed lost enhancer binding of HNF4A and GR mainly at kidney related enhancer elements. In contrast, STAT3 showed increased binding at injury induces enhancer elements. No dynamic was observed for STAT5. Both transcription factor groups show corresponding mRNA changes after injury. Pharmacological inhibition of enhancer and super-enhancer activity by BRD4 inhibition (JQ1: 50mg/kg/day) before IRI leads to suppression of 40% of injury-induced transcripts associated with cell cycle regulation and significantly increased mortality between days 2 and 3 after AKI. Conclusion This is the first demonstration of enhancer and super-enhancer function in the repairing kidney. In addition, our data call attention to potential caveats for use of small molecule inhibitors of BET proteins that are currently being tested in clinical trials in cancer patients who are at risk for AKI. Our analyses of enhancer dynamics after kidney injury in vivo have the potential to identify new targets for therapeutic intervention.

Ischemia-reperfusion: From cell biology to acute kidney injury

2014 ◽  
Vol 24 ◽  
pp. S4-S12 ◽  
Author(s):  
N. Chatauret ◽  
L. Badet ◽  
B. Barrou ◽  
T. Hauet
Keyword(s):  
Acute Kidney Injury ◽  
Cell Biology ◽  
Ischemia Reperfusion ◽  
Kidney Injury

COVID-19 aus Sicht des Nephrologen

2020 ◽  
Vol 145 (15) ◽  
pp. 1068-1073
Author(s):  
Martin Kann ◽  
Thomas Benzing
Keyword(s):  
Acute Kidney Injury ◽  
Kidney Transplantation ◽  
Current Knowledge ◽  
Early Stage ◽  
Kidney Tissue ◽  
Kidney Injury ◽  
Chronic Hemodialysis ◽  
Initial Presentation ◽  
Proximal Tubular ◽  
Insight Into

AbstractIncreasing insight into the clinical phenotype and mechanisms of SARS-CoV-2 infections and COVID-19 has identified damage of the kidneys as a key player in the course of the disease. This manuscript summarizes the current knowledge on direct viral infection of kidney tissue, proteinuria and acute kidney injury in COVID-19, and management of patients on chronic dialysis as well as after kidney transplantation. Direct infection of podocytes and proximal tubular cells by SARS-CoV-2 has been confirmed and results in proteinuria and hematuria at an early stage of COVID-19. In this context, any kidney affection is a predictor of worse outcomes among COVID-19 patients irrespective of the initial presentation and increases the risk of acute kidney injury. Specific therapies for kidney damage and acute kidney injury within COVID-19 that could be generally recommended are currently lacking. Patients on chronic hemodialysis in particular are at risk for contracting SARS-CoV-2 infections as indicated by outbreaks and super-spreading events in hemodialysis facilities. Immunosuppressive therapy after kidney transplantation needs to be adapted upon diagnosis of COVID-19 depending on the severity of the initial presentation.

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