Human Tubular Epithelial Cells Activate a Coordinated Stress Response after Serum Exposure [RNAseq-pid1830]
Ontology highlight
ABSTRACT: Proteinuria, the spillage of serum proteins into the urine, is a feature of glomerulonephritides, podocyte disorders and diabetic nephropathy. However, the response of tubular epithelial cells to serum protein exposure has not been systematically characterized. Using transcriptomic profiling we studied serum-induced changes in primary human tubular epithelial cells cultured in 3D microphysiological devices. Serum proteins induced cellular proliferation, secretion of cytokines and activated a coordinated stress response. We orthogonally confirmed our findings by comparing the transcriptomic and epigenomic landscapes of. Importantly, key transcriptomic programs in response to serum exposure remained consistent when comparing intact renal cortex to primary human tubules cultured in 10% fetal bovine serum and to an established mouse model of kidney injury. This serum-induced transcriptional response was dominated by AP-1 and NFkB signatures in the tubular epigenomic landscape with features of active regulation at canonical kidney injury genes (HAVCR1) and genes associated with COVID-19 (ACE2, IL6). Our data provide a reference map for dissecting the regulatory and transcriptional response of tubular epithelial cells to serum-induced injury.
Project description:Proteinuria, the spillage of serum proteins into the urine, is a feature of glomerulonephritides, podocyte disorders and diabetic nephropathy. However, the response of tubular epithelial cells to serum protein exposure has not been systematically characterized. Using transcriptomic profiling we studied serum-induced changes in primary human tubular epithelial cells cultured in 3D microphysiological devices. Serum proteins induced cellular proliferation, secretion of cytokines and activated a coordinated stress response. We orthogonally confirmed our findings by comparing the transcriptomic and epigenomic landscapes of. Importantly, key transcriptomic programs in response to serum exposure remained consistent when comparing intact renal cortex to primary human tubules cultured in 10% fetal bovine serum and to an established mouse model of kidney injury. This serum-induced transcriptional response was dominated by AP-1 and NFkB signatures in the tubular epigenomic landscape with features of active regulation at canonical kidney injury genes (HAVCR1) and genes associated with COVID-19 (ACE2, IL6). Our data provide a reference map for dissecting the regulatory and transcriptional response of tubular epithelial cells to serum-induced injury.
Project description:Our study investigates how RIPC modulates the transcriptomic profile of neutrophils and renal tubular epithelial cells in the kidney during acute kidney injury.
Project description:Ischemia-reperfusion injury-induced acute kidney injury is a major cause of chronic kidney disease, lacking effective interventions. We found elevated HNF3α expression in CKD patients, which correlated with collagen deposition, serum creatinine, and urea levels. Conditional knockout of HNF3α in renal tubular epithelial cells protected against IRI-induced renal fibrosis in vivo. To explore the mechanisms by which HNF3α promotes renal fibrosis, we transfected TKPTS cells with Hnf3a overexpression plasmids or control plasmids, and then performed transcriptome sequencing.
Project description:Our study investigates how the systemic administration of glutamine modulates the transcriptomic profile of neutrophils and renal tubular epithelial cells in the kidney during acute kidney injury.
Project description:Ischemia-reperfusion injury-induced acute kidney injury is a major cause of chronic kidney disease, lacking effective interventions. We found elevated HNF3α (also known as FOXA1) expression in CKD patients, which correlated with collagen deposition, serum creatinine, and urea levels. Conditional knockout of HNF3α in renal tubular epithelial cells protected against IRI-induced renal fibrosis in vivo. To explore the mechanisms by which HNF3α promotes renal fibrosis, we analyse the genome-wide target sites of HNF3α using CUT&Tag sequencing.
Project description:NF-κB is a key regulator of innate and adaptive immunity and is implicated in the pathogenesis of acute kidney injury (AKI). The cell type-specific functions of NF-κB in the kidney are unknown; however, the pathway serves distinct functions in immune and tissue-parenchymal cells. We analyzed tubular epithelial-specific NF-κB signaling in a mouse model of ischemia-reperfusion injury (IRI)-induced AKI. NF-κB reporter activity and nuclear localization of phosphorylated NF-κB subunit p65 analyses in mice revealed widespread NF-κB activation in renal tubular epithelia and in interstitial cells following IRI that peaked at 2-3 days after injury. To genetically antagonize tubular epithelial NF-κB activity, we generated mice expressing the human NF-κB super-repressor IκBα∆N in renal proximal, distal, and collecting duct epithelial cells. These mice were protected from IRI-induced AKI, as indicated by improved renal function, reduced tubular apoptosis, and attenuated neutrophil and macrophage infiltration. Tubular NF-κB-dependent gene expression profiles revealed temporally distinct functional gene clusters for apoptosis, chemotaxis, and morphogenesis. Primary proximal tubular cells isolated from IκBα∆N-expressing mice exposed to hypoxia-mimetic agent cobalt chloride were protected from apoptosis and expressed reduced levels of chemokines. Our results indicate that postischemic NF-κB activation in renal-tubular epithelia aggravates tubular injury and exacerbates a maladaptive inflammatory response.
Project description:NF-κB is a key regulator of innate and adaptive immunity and is implicated in the pathogenesis of acute kidney injury (AKI). The cell type-specific functions of NF-κB in the kidney are unknown; however, the pathway serves distinct functions in immune and tissue-parenchymal cells. We analyzed tubular epithelial-specific NF-κB signaling in a mouse model of ischemia-reperfusion injury (IRI)-induced AKI. NF-κB reporter activity and nuclear localization of phosphorylated NF-κB subunit p65 analyses in mice revealed widespread NF-κB activation in renal tubular epithelia and in interstitial cells following IRI that peaked at 2-3 days after injury. To genetically antagonize tubular epithelial NF-κB activity, we generated mice expressing the human NF-κB super-repressor IκBα∆N in renal proximal, distal, and collecting duct epithelial cells. These mice were protected from IRI-induced AKI, as indicated by improved renal function, reduced tubular apoptosis, and attenuated neutrophil and macrophage infiltration. Tubular NF-κB-dependent gene expression profiles revealed temporally distinct functional gene clusters for apoptosis, chemotaxis, and morphogenesis. Primary proximal tubular cells isolated from IκBα∆N-expressing mice exposed to hypoxia-mimetic agent cobalt chloride were protected from apoptosis and expressed reduced levels of chemokines. Our results indicate that postischemic NF-κB activation in renal-tubular epithelia aggravates tubular injury and exacerbates a maladaptive inflammatory response.
Project description:Streptozotocin (STZ) is an anti-cancer drug that is primarily used to treat neuroendocrine tumors (NETs) in clinical settings and develop type 1 diabetes rodent models in experimental fields. STZ is incorporated into cells through the glucose transporter, GLUT2, which is primarily expressed in pancreatic β-cells or proximal tubular epithelial cells in the kidney. However, its cytotoxic effects on kidney cells have been underestimated and the underlying mechanisms remain unclear. We herein demonstrated that DNA damage and subsequent p53 signaling were responsible for the development of STZ-induced tubular epithelial injury. We detected tubular epithelial DNA damage in NET patients treated with STZ. Unbiased transcriptomics of tubular epithelial cells in vitro showed the activation of the p53 signaling pathway by STZ. STZ induced DNA damage and activated p53 signaling in vivo in a dose-dependent manner, resulting in reduced membrane transport. The localization of STZ-induced kidney injury was limited to within the kidney cortex, which was independent of blood glucose. The pharmacological inhibition of p53 and sodium-glucose transporter 2 (SGLT2) mitigated STZ-induced epithelial injury. However, the cytotoxic effects of STZ on pancreatic β-cells were preserved in SGLT2 inhibitor-treated mice. The present results demonstrate the strong proximal tubular-specific cytotoxicity of STZ and the underlying mechanisms in vivo, which may be ameliorated by a SGLT2 inhibitor pretreatment. Since the cytotoxic effects of STZ against β-cells were not impaired by dapagliflozin, a pretreatment with a SGLT2 inhibitor has potential as a preventative remedy for kidney injury in NET patients treated with STZ.
Project description:Acute kidney injury (AKI) represents a common complication in critically ill patients that is associated with an increased morbidity and mortality. Currently, no effective treatment options are available. Here, we show that glutamine significantly attenuates leukocyte recruitment and inflammatory signaling in human and murine tubular epithelial cells (TECs). In a murine AKI model induced by ischemia-reperfusion-injury (IRI) we show that glutamine causes transcriptomic and proteomic reprogramming in renal TECs and neutrophils, resulting in decreased epithelial apoptosis, neutrophil recruitment and improved mitochondrial functionality and respiration provoked by an ameliorated oxidative phosphorylation. We identify the proteins glutamine gamma glutamyltransferase 2 (Tgm2) and apoptosis signal-regulating kinase (Ask1) as the major targets of glutamine in apoptotic signaling. Increased Tgm2 expression and reduced Ask1 activation result in decreased JNK activation leading to a diminished mitochondrial intrinsic apoptosis in kidneys upon IRI-induced AKI and under hypoxia or following TNFα-treatment of TECs. Consequently, glutamine administration attenuated kidney injury in vivo during AKI progression as well as TEC viability in vitro under inflammatory and hypoxic conditions.
Project description:Hyperlipidemia, an important risk factor for cardiovascular diseases and end-stage renal disease, often increases renal injury and compromises kidney function. In the present study, the kidney histology analysis in human samples showed that high lipid levels induced renal fibrosis. However, the mechanism of lipid nephrotoxicity remains unknown. We employed mice models of two kinds to further experiments. The kidney histology analysis in mouse showed that high lipid levels induced renal fibrosis that was further confirmed by Western blot and real-time PCR of fibrotic indexes (fibronection, collagenI and α-SMA). In Vitro analysis also supported that OX-LDL significantly induced fibrotic response in HK-2 tubular epithelial cells. To further ascertain the mechanism of high lipid-induced fibrosis, RNA-sequencing (RNA-Seq) was performed. Combined the Gene Ontology (GO) analysis results of differentially expressed mRNAs obtained by RNA-Seq with the results of LC-MS/MS and STRING Functional Association Networks showed that CD47 modulated the interaction of γ-catenin with E-cadherin and participated in epithelial–mesenchymal transformation in lipid nephrotoxicity. The inhibition of CD47 expression by transfected with shRNA plasmid or treated with anti-CD47 antibody in OX-LDL-treated tubular epithelial cells restored the expression of E-cadherin and attenuated renal injury including fibrosis and inflammatory response. These findings indicate that CD47 may be a therapeutic potential target for long-term lipid abuse-induced kidney injury.