Project description:To clarify the effects of cisplatin (cis-diamminedichloroplatinum II, CDDP) on the gene expression profiles in renal proximal tubules, microarray analyses were carried out using total RNA samples isolated from microdissected proximal tubules and whole kidneys. The molecular events underlying acute kidney injury (AKI) in the proximal tubules of rats with cisplatin-induced nephrotoxicity were successfully clarified with 17,000 transcripts. Renal proximal tubules were isolated under microscopy, and transcriptome data were collected with Rat Genome Survey Microarray® (Applied Biosystems)
Project description:To clarify the effects of cisplatin (cis-diamminedichloroplatinum II, CDDP) on the gene expression profiles in renal proximal tubules, microarray analyses were carried out using total RNA samples isolated from microdissected proximal tubules and whole kidneys. The molecular events underlying acute kidney injury (AKI) in the proximal tubules of rats with cisplatin-induced nephrotoxicity were successfully clarified with 17,000 transcripts.
Project description:Background- CINAC-patients can be identified by the recently discovered renal proximal tubular cell lysosomal lesions which are also observed in patients experiencing calcineurin inhibitor (CNI) nephrotoxicity, suggesting that CINAC is a toxin-induced nephropathy. An alternative hypothesis advocates chronic heat stress/dehydration as the major etiological factor for CINAC. Here, we evaluated in rats to what extent heat stress/dehydration reflects the renal CINAC histopathology in humans. Methods- Wistar rats were divided in 3 groups. Group 1(n=6) had free access to drinking water (control group). Group 2(n=8) was water deprived for 10 hours per 24hr, 5 days/week and placed in an incubator (37°C) for 30 min/hr during water deprivation. Group 3(n=8) underwent daily oral gavage with cyclosporine (40mg/kg body weight). After 28 days kidneys were collected for light- and electron microscopic histopathology and proteomic analysis. Results- Cyclosporine rats developed renal cortical lesions mimicking those of CINAC patients i.e. atrophic proximal tubules with associated tubulo-interstitial fibrosis. PASM staining demonstrated enlarged argyrophilic granules in the affected proximal tubules, identified as lysosomes by LAMP1 immunofluorescent staining. Electron microscopy confirmed the presence of enlarged dysmorphic lysosomes, closely mimicking the dysmorphic lysosomes seen in CINAC-patients. Dehydration was demonstrated by urinary osmolality and fluctuating body weight but showed none of the histological features of CINAC patients. Proteomic analysis confirmed cellular toxicity of cyclosporine, whereas the dehydration group lacked any of these toxicity markers. Conclusion- Dehydration/heat stress alone does not lead to the renal proximal tubular and interstitial lesions as observed in CINAC-patients. The histopathological analogy between CINAC and CNI nephrotoxicity in rats and humans and CINAC supports the toxicological etiology.
Project description:The endocytic receptor megalin constitutes the main pathway for clearance of plasma proteins from the glomerular filtrate in the proximal tubules. However, little is know about the mechanisms that control receptor activity. A widely discussed hypothesis states that the intracellular domain (ICD) of megalin, released upon ligand binding, acts as a transcription regulator to suppress receptor expression - a mechanism proposed to safeguard the proximal tubules from protein overload. Here, we have put this hypothesis to the test by generating a mouse model co-expressing the soluble ICD and the full-length receptor. Despite pronounced expression in the proximal tubules, the ICD failed to exert any effects on renal proximal tubular function such as megalin expression, protein retrieval, or renal gene transcription. Thus, our data argue that the ICD does not play a role in regulation of megalin activity in vivo in the proximal tubules. We used microarrays to compare gene expression profile in adult kidney from a new mouse model expressing the intracellular domain of megalin with wildtype. 10 week old mice were collected for RNA extraction and hybridization on Affymetrix microarrays. Three individuals for each genotype were analyzed comparing heterozygous animals for the intracellular domain of megalin with littermates controls.
Project description:The endocytic receptor megalin constitutes the main pathway for clearance of plasma proteins from the glomerular filtrate in the proximal tubules. However, little is know about the mechanisms that control receptor activity. A widely discussed hypothesis states that the intracellular domain (ICD) of megalin, released upon ligand binding, acts as a transcription regulator to suppress receptor expression - a mechanism proposed to safeguard the proximal tubules from protein overload. Here, we have put this hypothesis to the test by generating a mouse model co-expressing the soluble ICD and the full-length receptor. Despite pronounced expression in the proximal tubules, the ICD failed to exert any effects on renal proximal tubular function such as megalin expression, protein retrieval, or renal gene transcription. Thus, our data argue that the ICD does not play a role in regulation of megalin activity in vivo in the proximal tubules. We used microarrays to compare gene expression profile in adult kidney from a new mouse model expressing the intracellular domain of megalin with wildtype.
Project description:Acute kidney injury (AKI) have been thought to be reversible condition, however, emerging evidence demonstrated association between AKI and subsequent development of irreversible fibrosis and chronic kidney disease. In the present study, since recovery of AKI depends on renal tubular regeneration, factors expressing in renal tubules in adaptive or maladaptive repair process were investigated to predict reversibility of kidney injury. In the kidney of female F344 rats subjected to ischemia/reperfusion (I/R), regenerative tubules and dilated tubules were observed at 3 and 7 days after I/R. In fibrotic areas of the kidney of male SD rats subjected to I/R, renal tubules were dilated or atrophied. From microarray data of regenerative tubules, survivin, sex-determining region Y (SRY)-box 9 (SOX9), and CD44 were extracted as factors possibly relating to tubular regeneration or fibrosis. Immunohistochmical analysis demonstrated that survivin and SOX9 expressed in regenerative tubules, while SOX9 also expressed in renal tubules in fibrotic area, indicating that survivin and SOX9 contribute renal tubular regeneration, but sustained SOX9 expression may lead fibrosis. CD44 expressed in dilated tubules at day 3 and 7, and tubules in fibrotic area, suggesting that CD44 expressed in maladaptive tubules. These information will be helpful to consider reversibility of kidney injury.
Project description:We extracted proximal renal tubules of WT and Lonp1-cKO mice (n=3), and then performed isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative proteomic analysis to assess differential protein-expression levels.
Project description:Multipotent progenitor cells (MPs) have been observed in human kidneys and particularly in Bowman's capsule and proximal tubules. The kidney owns the ability to repair local damage and renal MPs may play a role in the regenerative processes. Microarray technology was applied to identify differentially expressed genes among resident MPs isolated from glomeruli and tubules of normal renal tissue, renal proximal tubular epithelial cells (RPTECs) and mesenchymal stem cells (MSCs). The results of our analysis represent a starting point for further functional studies. Experiment Overall Design: This study includes three renal tissue samples which were processed to obtain 3 glomerular progenitor populations and 3 tubular ones. Three subcoltures of MSCs and RPTECs were included as well. The differences in gene expression patterns of the 4 cell types were found out.
Project description:We used micro-dissection techniques and/or FACS to isolate cell types from the developing and adult kidney (E11.5 ureteric buds, E12.5, P1 and P4 cap mesenchyme, E15.5 collecting ducts, proximal tubules, ureter, Adult renal proximal tubules, podocytes, endothelial and mesangial cells). RNA-SEQ analysis was performed to determine the transcriptional profile of each cell type, identify component specific transcripts and isoforms and cell-type specific long-noncoding RNAs. In addition the unbiased nature of RNA-SEQ will potentially identify novel transcripts that have not been annotated in the database. Total RNA is obtained from micro-dissected and/or FACS isolated embryonic and adult kidney components. The long term goal is to generate a transcriptional atlas of developing kidney.
Project description:We used micro-dissection techniques and/or FACS to isolate cell types from the developing and adult kidney (E11.5 ureteric buds, E12.5, P1 and P4 cap mesenchyme, E15.5 collecting ducts, proximal tubules, ureter, Adult renal proximal tubules, podocytes, endothelial and mesangial cells). RNA-SEQ analysis was performed to determine the transcriptional profile of each cell type, identify component specific transcripts and isoforms and cell-type specific long-noncoding RNAs. In addition the unbiased nature of RNA-SEQ will potentially identify novel transcripts that have not been annotated in the database.