Project description:To assess the transcriptomic response to Klotho deficiency in the renal distal convolution (DC), we isolated DC cells from control and DC-specific Klotho KO mice using COPAS (Complex Object Parametric Analyzer and Sorter). Further comprehensive and unbiased RNA-seq identified altered transcripts associated with canonical MAPK pathway, as well as many novel targets of Klotho.
Project description:Study the role of klotho as a tumor suppressor in colorectal cancer. [abstract] Klotho is an anti-aging transmembrane protein, which can be shed and function as a hormone. Accumulating data indicate klotho as a tumor suppressor in a wide array of malignancies and indicate the subdomain KL1 as the active region of the protein. We aimed to study the role of klotho as a tumor suppressor in colorectal cancer. Bioinformatics analyses of TCGA datasets indicated reduced klotho mRNA levels in human colorectal cancer, along with negative regulation of klotho expression by hypermethylation of the promoter and 1st exon, and hypomethylation of an area within the gene. Overexpression or treatment with klotho or KL1 inhibited proliferation of colorectal cancer cells in vitro. The in vivo activity of klotho and KL1 was examined using two models recapitulating development of tumors in the normal colonic environment of immune-competent mice. Treatment with klotho inhibited formation of colon polyps induced by the carcinogen azoxymethane, and KL1 treatment slowed growth of orthotopically-implanted colorectal tumors. Gene expression array revealed that klotho and KL1 expression enhanced the unfolded protein response (UPR) and this was further established by increased levels of spliced XBP1, GRP78 and phosphorylated eIF2α. Furthermore, attenuation of the UPR partially abrogated klotho tumor suppressor activity. In conclusion, this study indicates klotho as a tumor suppressor in colorectal cancer and identifies, for the first time, the UPR as a pathway mediating klotho activities in cancer. These data suggest that administration of exogenous klotho or KL1 may serve as a novel strategy for prevention and treatment of colorectal cancer.
Project description:The renal distal convoluted tubule DCT is a short part of the distal nephron with specific functions transporting ions and thereby modifying Na, Ca, Mg, K balance A transcriptomic analysis of the DCT was performed to identify specific gene expression which would implicate those genes in specific DCT function Fluorescent DCT (EGFP+) were sorted out from a renal tubule suspension by a COPAS (Complex Object Parametric analyser and sorter). EGFP- and the total (ALL) fractions were also sorted by COPAS. Gene expression for each fractions (EGFP+, EGFP-, ALL) was performed in 4 mice
Project description:The renal distal convoluted tubule DCT is a short part of the distal nephron with specific functions transporting ions and thereby modifying Na, Ca, Mg, K balance A transcriptomic analysis of the DCT was performed to identify specific gene expression which would implicate those genes in specific DCT function
Project description:α-Klotho has emerged as a powerful regulator of the ageing process. To-date, the expression profile of α-Klotho in human tissues is unknown and its existence in some human tissue types is subject to much controversy. Objective: This is the first study to characterize system-wide tissue expression of transmembrane α-Klotho in humans. We have employed next generation targeted proteomic analysis using Parallel Reaction Monitoring (PRM) in parallel with conventional antibody-based methods to determine the expression and spatial distribution of human α-Klotho expression in health. Results: The distribution of α-Klotho in human tissues from various organ systems, including arterial, epithelial, endocrine, reproductive and neuronal tissues was first identified by immunohistochemistry. Kidney tissues showed strong α-Klotho expression, while liver did not reveal a detectable signal. These results were next confirmed by western blotting of both whole tissues and primary cells. To validate our antibody-based results, α-Klotho expressing tissues were subjected to PRM mass spectrometry identifying peptides specific for the full length, transmembrane α-Klotho isoform. Conclusions: The data presented confirms α-Klotho expression in the kidney tubule and in artery, and provides evidence of α-Klotho expression across organ systems and cell-types that have not previously been described in humans.
Project description:Sexual dimorphism in kidney injury markers, such as Klotho, is frequently underestimated or disregarded, as most of the preclinical research is done in male animals. Klotho is well-linked to renal health and its deletion in mice results in a severe accelerated aging-like phenotype and premature death. Here, we identified candidate Klotho enhancers and discovered their function using mice carrying deletions in the enhancer loci. Candidate Klotho enhancers were deleted using CRISPR/Cas9 genome editing. Warm ischemia-reperfusion surgery (IRI) was performed bilaterally to induce acute kidney injury and unilaterally in a fibrosis model. Using ChIP-seq and RNA-seq, we analyzed renal chromatin features and gene expression. ELISA and colorimetric assays were used to measure serum FGF23 and serum component levels. Removal of the enhancer caused more substantial reduction in Klotho mRNA levels in female mice compared to males (90 vs. 50%), supported by gene promoter marks remaining more pronounced in males. Weight, lifespan, and fertility of mice lacking the enhancers were not impacted. Only male mutant mice displayed higher Havcr1 expression after IRI than controls (mean 1048 vs. 231.4, p=0.0016). 28 days after unilateral IRI, only males displayed increased fibrosis markers, but with no difference between genotypes. Our findings reveal sexual dimorphism of Klotho gene expression and its enhancer regulation. Only male mutant mice were more susceptible to acute injury and the enhancer deletion had no impact on fibrosis. Additional investigation into the mechanisms governing Klotho regulation is imperative to reassess its effectiveness as a kidney injury marker.
Project description:Sexual dimorphism in kidney injury markers, such as Klotho, is frequently underestimated or disregarded, as most of the preclinical research is done in male animals. Klotho is well-linked to renal health and its deletion in mice results in a severe accelerated aging-like phenotype and premature death. Here, we identified candidate Klotho enhancers and discovered their function using mice carrying deletions in the enhancer loci. Candidate Klotho enhancers were deleted using CRISPR/Cas9 genome editing. Warm ischemia-reperfusion surgery (IRI) was performed bilaterally to induce acute kidney injury and unilaterally in a fibrosis model. Using ChIP-seq and RNA-seq, we analyzed renal chromatin features and gene expression. ELISA and colorimetric assays were used to measure serum FGF23 and serum component levels. Removal of the enhancer caused more substantial reduction in Klotho mRNA levels in female mice compared to males (90 vs. 50%), supported by gene promoter marks remaining more pronounced in males. Weight, lifespan, and fertility of mice lacking the enhancers were not impacted. Only male mutant mice displayed higher Havcr1 expression after IRI than controls (mean 1048 vs. 231.4, p=0.0016). 28 days after unilateral IRI, only males displayed increased fibrosis markers, but with no difference between genotypes. Our findings reveal sexual dimorphism of Klotho gene expression and its enhancer regulation. Only male mutant mice were more susceptible to acute injury and the enhancer deletion had no impact on fibrosis. Additional investigation into the mechanisms governing Klotho regulation is imperative to reassess its effectiveness as a kidney injury marker.
Project description:Sexual dimorphism in kidney injury markers, such as Klotho, is frequently underestimated or disregarded, as most of the preclinical research is done in male animals. Klotho is well-linked to renal health and its deletion in mice results in a severe accelerated aging-like phenotype and premature death. Here, we identified candidate Klotho enhancers and discovered their function using mice carrying deletions in the enhancer loci. Candidate Klotho enhancers were deleted using CRISPR/Cas9 genome editing. Warm ischemia-reperfusion surgery (IRI) was performed bilaterally to induce acute kidney injury and unilaterally in a fibrosis model. Using ChIP-seq and RNA-seq, we analyzed renal chromatin features and gene expression. ELISA and colorimetric assays were used to measure serum FGF23 and serum component levels. Removal of the enhancer caused more substantial reduction in Klotho mRNA levels in female mice compared to males (90 vs. 50%), supported by gene promoter marks remaining more pronounced in males. Weight, lifespan, and fertility of mice lacking the enhancers were not impacted. Only male mutant mice displayed higher Havcr1 expression after IRI than controls (mean 1048 vs. 231.4, p=0.0016). 28 days after unilateral IRI, only males displayed increased fibrosis markers, but with no difference between genotypes. Our findings reveal sexual dimorphism of Klotho gene expression and its enhancer regulation. Only male mutant mice were more susceptible to acute injury and the enhancer deletion had no impact on fibrosis. Additional investigation into the mechanisms governing Klotho regulation is imperative to reassess its effectiveness as a kidney injury marker.
Project description:Mutations of the β-glucuronidase protein α-Klotho have been associated with premature aging, and altered cognitive function. Although highly expressed in specific areas of the brain, Klotho functions in the central nervous system remain unknow. Here, we show that cultured hippocampal neurons respond to insulin and glutamate stimulation by elevating Klotho protein levels. Conversely, AMPA and NMDA antagonism suppress neuronal Klotho expression. We also provide evidence that soluble Klotho enhances astrocytic aerobic glycolysis by hindering pyruvate metabolism through the mitochondria, and stimulating its processing by lactate dehydrogenase. Pharmacological inhibition of FGFR1, Erk phosphorylation, and monocarboxylic acid transporters prevents Klotho-induced lactate release from astrocytes. Taken together these data suggest Klotho is a potential new player in the metabolic coupling between neurons and astrocytes. Neuronal glutamatergic activity and insulin modulation elicit Klotho release, which in turn stimulates astrocytic lactate formation and release. Lactate can then be used by neurons as a metabolic substrate contributing to fulfill their elevated energy requirements.
Project description:The expression profiles of miRNAs in klotho-deficient and wild-type mice were examined by means of GenopalM-BM-.-MICM DNA chips. The data suggested that there was a difference in the expression of miRNAs between klotho-deficient and wild-type mice. Small RNA samples prevared from 5-week-old klotho-deficient and wild-type mice were examined.