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1.
Environ Res ; 242: 117768, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38040177

ABSTRACT

Agricultural low-carbon production emerges as a pivotal function for achieving sustainable green development. However, there remains insufficient empirical evidence regarding the effect of environmental regulations and green subsidies upon the low-carbon production behavior of new agricultural entities. In this study, a questionnaire survey was administered to 268 respondents representing new agricultural entities in Guangdong Province, P.R.C. Subsequently, a structural equation model had been employed for validation analysis. This study's findings demonstrate that in general, environmental regulations positively and significantly affect the behavior of agricultural low-carbon production. Conversely, the influence of green subsidies is not statistically significant. In addition, differences are observed across different sectors, with environmental regulations significantly affecting low-carbon production behavior in the plantation sector, but not in the livestock sector. Conversely, green subsidies significantly impact low-carbon production behavior in the livestock sector, but not in the plantation sector. These findings highlight the promotional role of government-enforced environmental regulations and green subsidies in fostering low-carbon agricultural practices. Therefore, new agricultural entities should strive to augment green production technology capacities to realize sustainable green development.


Subject(s)
Agriculture , Technology , Carbon , Government Regulation , China
2.
Environ Sci Pollut Res Int ; 30(15): 42813-42828, 2023 Mar.
Article in English | MEDLINE | ID: mdl-34799797

ABSTRACT

Prior studies on environmental standards have highlighted the significance of urbanization and transportation in affecting environmental sustainability worldwide. As the empirical and theoretical debates are still unresolved and divisive, the argument of whether urbanization, transportation and economic growth in Association of Southeast Asian Nations (ASEAN) countries cause greenhouse gas (GHG) emissions remains unclear. This study aim is to examine dynamic linkage between transportation, urbanization, economic growth and GHG emissions, as well as the impact of environmental regulations on GHG emission reduction in ASEAN countries over the years 1995-2018. On methodological aspects, the study accompanies a few environmental studies that check the cross-sectional dependence and slope heterogeneity issues. Moreover, the new cross-sectionally augmented autoregressive distributed lags (CS-ARDL) methodology is also applied in the study to estimate the short-run and long-run effects of the factors on GHG emissions. Substantial evidence is provided that GHG emissions increase with transportation, urbanization and economic growth but decrease with the imposition of environmental-related taxations. Augmented mean group (AMG) and common correlated effect mean group (CCEMG) also support the findings of CS-ARDL estimates. Finally, the study calls for drastic actions in ASEAN countries to reduce GHG emissions, including environmentally friendly transportation services and environmental regulation taxes. This study also provides the guidelines to the regulators while developing policies related to control the GHG emission in the country.


Subject(s)
Economic Development , Greenhouse Gases , Urbanization , Cross-Sectional Studies , Environmental Pollution/analysis , Greenhouse Gases/analysis , Carbon Dioxide/analysis
3.
Environ Sci Pollut Res Int ; 30(15): 42753-42765, 2023 Mar.
Article in English | MEDLINE | ID: mdl-34652619

ABSTRACT

There is a shred of evidence of environmental degradation in the form of carbon emissions to behave differently when tested with different macroeconomic variables. This paper aims to examine the long-run and short-run association between natural resource rent, financial development, and urbanization on carbon emission from the context of the USA during 1995-2015 with the help of a contemporary and innovative approach named quantile autoregressive distributed lagged model (QARDL). The stated approach is applied due to the fact that non-linearity is observed for the study variables. The findings indicated that the higher financial development (0.304), natural resource rent (0.102), and urbanization (0.489) have a positive impact on the environmental degradation in the region of USA during long-run estimation in the stated quantiles of the study. This would indicate that higher financial development, urbanization, and natural resources are putting more environmental pressure on the economy of the USA. Similarly, the findings under short-run estimation confirm that past and lagged values of carbon emission, financial development, natural resource rent, and urbanization are significantly determining the current values of the carbon emission. For this reason, it is suggested that the government requires some immediate steps of the USA to control the harmful effect of such financial development, more urbanization, and higher natural resource rent as well. This would indicate the reflection of some green strategies in all three explanatory variables to generate some fruitful environmental outcomes.


Subject(s)
Carbon , Urbanization , Carbon Dioxide , Natural Resources , Economic Development
4.
Front Psychol ; 12: 732659, 2021.
Article in English | MEDLINE | ID: mdl-34925142

ABSTRACT

Entrepreneurship may be taught, and entrepreneurship education is flourishing at colleges and universities. However, previous documents show that entrepreneurship education is inconsistent with the research conclusions of entrepreneurial intention, which is a lack of discussion on the mediating effect of government subsidies from external resources. Based on the cognitive behavior theory, a mediating effect of entrepreneurship education on entrepreneurial strategy and entrepreneurial intention is built. By collecting the data of 334 questionnaires of college students in Pearl River Delta in China, a structural equation is used for empirical analysis. The result indicates that entrepreneurship education does not have a significant influence on entrepreneurial intention; exploration innovation and exploitation innovation have a positive influence on entrepreneurial intention, and exploration innovation and exploitation innovation have a mediating effect on entrepreneurship education and entrepreneurial intention; government subsidies have a positive regulating effect on exploration innovation, exploitation innovation, and entrepreneurial intention. In this article, the application of the cognitive behavior theory in the field of entrepreneurship research is expanded to provide the theoretical basis for building the entrepreneurship education ecosystem, which is conductive to innovation and entrepreneurship to promote regional economic development.

5.
Sci Adv ; 7(45): eabi8051, 2021 Nov 05.
Article in English | MEDLINE | ID: mdl-34739325

ABSTRACT

Genome-wide association studies (GWAS) have identified hundreds of genetic risk regions for kidney dysfunction [estimated glomerular filtration rate (eGFR)]; however, the causal genes, cell types, and pathways are poorly understood. Integration of GWAS and human kidney expression of quantitative trait analysis using Bayesian colocations, transcriptome-wide association studies, and summary-based Mendelian randomization studies prioritized caspase-9 (CASP9) as a kidney disease risk gene. Human kidney single-cell epigenetic and immunostaining studies indicated kidney tubule cells as a disease-causing cell type. Mice with genetic deletion or pharmacological inhibition of CASP9 showed lower apoptosis while having improved mitophagy, resulting in dampened activation of cytosolic nucleotide sensing pathways (cGAS-STING), reduction of inflammation, and protection from acute kidney disease or renal fibrosis. In summary, here, we prioritized CASP9 as an eGFR GWAS target gene and demonstrated the causal role of CASP9 in kidney disease development via improving mitophagy and lowering inflammation and apoptosis.

6.
J Clin Invest ; 131(10)2021 05 17.
Article in English | MEDLINE | ID: mdl-33998598

ABSTRACT

Genome-wide association studies (GWAS) for kidney function identified hundreds of risk regions; however, the causal variants, target genes, cell types, and disease mechanisms remain poorly understood. Here, we performed transcriptome-wide association studies (TWAS), summary Mendelian randomization, and MetaXcan to identify genes whose expression mediates the genotype effect on the phenotype. Our analyses identified Dachshund homolog 1 (DACH1), a cell-fate determination factor. GWAS risk variant was associated with lower DACH1 expression in human kidney tubules. Human and mouse kidney single-cell open chromatin data (snATAC-Seq) prioritized estimated glomerular filtration rate (eGFR) GWAS variants located on an intronic regulatory region in distal convoluted tubule cells. CRISPR-Cas9-mediated gene editing confirmed the role of risk variants in regulating DACH1 expression. Mice with tubule-specific Dach1 deletion developed more severe renal fibrosis both in folic acid and diabetic kidney injury models. Mice with tubule-specific Dach1 overexpression were protected from folic acid nephropathy. Single-cell RNA sequencing, chromatin immunoprecipitation, and functional analysis indicated that DACH1 controls the expression of cell cycle and myeloid chemotactic factors, contributing to macrophage infiltration and fibrosis development. In summary, integration of GWAS, TWAS, single-cell epigenome, expression analyses, gene editing, and functional validation in different mouse kidney disease models identified DACH1 as a kidney disease risk gene.


Subject(s)
Databases, Nucleic Acid , Eye Proteins , Kidney Diseases , Kidney Tubules/metabolism , Transcription Factors , Transcriptome , Animals , Disease Models, Animal , Eye Proteins/biosynthesis , Eye Proteins/genetics , Genome-Wide Association Study , Humans , Kidney Diseases/genetics , Kidney Diseases/metabolism , Male , Mice , Mice, Transgenic , Risk Factors , Transcription Factors/biosynthesis , Transcription Factors/genetics
7.
Sci Transl Med ; 13(576)2021 01 13.
Article in English | MEDLINE | ID: mdl-33441424

ABSTRACT

More than 800 million people in the world suffer from chronic kidney disease (CKD). Genome-wide association studies (GWAS) have identified hundreds of loci where genetic variants are associated with kidney function; however, causal genes and pathways for CKD remain unknown. Here, we performed integration of kidney function GWAS and human kidney-specific expression quantitative trait analysis and identified that the expression of beta-mannosidase (MANBA) was lower in kidneys of subjects with CKD risk genotype. We also show an increased incidence of renal failure in subjects with rare heterozygous loss-of-function coding variants in MANBA using phenome-wide association analysis of 40,963 subjects with exome sequencing data. MANBA is a lysosomal gene highly expressed in kidney tubule cells. Deep phenotyping revealed structural and functional lysosomal alterations in human kidneys from subjects with CKD risk alleles and mice with genetic deletion of Manba Manba heterozygous and knockout mice developed more severe kidney fibrosis when subjected to toxic injury induced by cisplatin or folic acid. Manba loss altered multiple pathways, including endocytosis and autophagy. In the absence of Manba, toxic acute tubule injury induced inflammasome activation and fibrosis. Together, these results illustrate the convergence of common noncoding and rare coding variants in MANBA in kidney disease development and demonstrate the role of the endolysosomal system in kidney disease development.


Subject(s)
Kidney Diseases , beta-Mannosidase , Animals , Genome-Wide Association Study , Humans , Kidney Diseases/genetics , Lysosomes , Mannosidases , Mice , Risk Factors , Severity of Illness Index , beta-Mannosidase/genetics
8.
Cell Metab ; 33(2): 379-394.e8, 2021 02 02.
Article in English | MEDLINE | ID: mdl-33301705

ABSTRACT

Kidney disease is poorly understood because of the organ's cellular diversity. We used single-cell RNA sequencing not only in resolving differences in injured kidney tissue cellular composition but also in cell-type-specific gene expression in mouse models of kidney disease. This analysis highlighted major changes in cellular diversity in kidney disease, which markedly impacted whole-kidney transcriptomics outputs. Cell-type-specific differential expression analysis identified proximal tubule (PT) cells as the key vulnerable cell type. Through unbiased cell trajectory analyses, we show that PT cell differentiation is altered in kidney disease. Metabolism (fatty acid oxidation and oxidative phosphorylation) in PT cells showed the strongest and most reproducible association with PT cell differentiation and disease. Coupling of cell differentiation and the metabolism was established by nuclear receptors (estrogen-related receptor alpha [ESRRA] and peroxisomal proliferation-activated receptor alpha [PPARA]) that directly control metabolic and PT-cell-specific gene expression in mice and patient samples while protecting from kidney disease in the mouse model.


Subject(s)
Kidney Diseases/metabolism , Receptors, Estrogen/metabolism , Animals , Cell Differentiation , Cells, Cultured , Kidney Diseases/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Receptors, Estrogen/deficiency , ERRalpha Estrogen-Related Receptor
9.
Front Psychol ; 11: 1976, 2020.
Article in English | MEDLINE | ID: mdl-33013508

ABSTRACT

Ecological innovation is an inevitable trend for firms to enhance competitiveness and sustainably operate in the context of green economy. The previous literature has rarely discussed the influence of ambidextrous learning on the eco-innovation performance of startups and ignored the moderating effect of top management's environmental awareness from the perspective of microscopic psychology. We have conducted a questionnaire survey on 212 firms established within 4 years in the Pearl River Delta of China, using the structure mode and the PROCESS by Hayes (2013) to analyze the influence of ambidextrous learning, such as exploratory learning and exploitative learning, by startups on eco-innovation performance and verify the moderating effect of top management's environmental awareness. The results show that exploratory learning and exploitative learning have a positive and significant influence on eco-innovation performance, indicating that the organizational learning of startups is conducive to improving eco-innovation performance; under the moderating effect of top management's environmental awareness, the influence of exploratory learning and exploitative learning on eco-innovation performance may differ. The results also show that in the process of organizing ambidextrous learning, startups should help raise the environmental awareness of top management to improve the eco-innovation performance, thus providing guidance for startups to carry out eco-innovation activities and for local governments to make decisions on green economy.

10.
Cell Metab ; 30(4): 784-799.e5, 2019 10 01.
Article in English | MEDLINE | ID: mdl-31474566

ABSTRACT

Fibrosis is the final common pathway leading to end-stage renal failure. By analyzing the kidneys of patients and animal models with fibrosis, we observed a significant mitochondrial defect, including the loss of the mitochondrial transcription factor A (TFAM) in kidney tubule cells. Here, we generated mice with tubule-specific deletion of TFAM (Ksp-Cre/Tfamflox/flox). While these mice developed severe mitochondrial loss and energetic deficit by 6 weeks of age, kidney fibrosis, immune cell infiltration, and progressive azotemia causing death were only observed around 12 weeks of age. In renal cells of TFAM KO (knockout) mice, aberrant packaging of the mitochondrial DNA (mtDNA) resulted in its cytosolic translocation, activation of the cytosolic cGAS-stimulator of interferon genes (STING) DNA sensing pathway, and thus cytokine expression and immune cell recruitment. Ablation of STING ameliorated kidney fibrosis in mouse models of chronic kidney disease, demonstrating how TFAM sequesters mtDNA to limit the inflammation leading to fibrosis.


Subject(s)
DNA, Mitochondrial/metabolism , Kidney Tubules/metabolism , Membrane Proteins/metabolism , Mitochondria/metabolism , Renal Insufficiency, Chronic/pathology , Animals , DNA-Binding Proteins/metabolism , Epithelial Cells/metabolism , Epithelial Cells/pathology , Fibrosis , Humans , Inflammation/pathology , Kidney Tubules/pathology , Male , Mice , Mitochondrial Proteins/metabolism , RAW 264.7 Cells , Transcription Factors/metabolism
11.
Curr Opin Nephrol Hypertens ; 28(3): 219-226, 2019 05.
Article in English | MEDLINE | ID: mdl-30844884

ABSTRACT

PURPOSE OF REVIEW: Transcriptome analysis of human kidney samples provides an integrated output of genetic, physiological, or environmental inputs. This review summarizes recent findings including gene expression and genetic variation integration, bulk and single cell gene expression analysis, and describes how such studies have improved our understanding of kidney disease development. RECENT FINDINGS: Bulk or whole tissue analysis of patient kidney samples identified a large number of genes, whose levels correlate with kidney function and/or structural damage. These genes were enriched for metabolic and immune functions. Using expression quantitative trait analysis, genetic variations-driven gene expression can be identified. Recent developments in single cell sequencing defined cell-type-specific gene expression changes and highlighted specific cell types for disease development. SUMMARY: Recent advancement in whole tissue transcriptomics, specifically incorporating genotype information and single cell data have been powerful to identify kidney disease-associated genes, pathways, and cell types.


Subject(s)
Gene Expression Profiling , Kidney/metabolism , Genotype , Humans , Kidney Diseases/etiology , Kidney Diseases/genetics , Sequence Analysis, RNA , Single-Cell Analysis
12.
Nat Med ; 24(11): 1721-1731, 2018 11.
Article in English | MEDLINE | ID: mdl-30275566

ABSTRACT

Chronic kidney disease (CKD), a condition in which the kidneys are unable to clear waste products, affects 700 million people globally. Genome-wide association studies (GWASs) have identified sequence variants for CKD; however, the biological basis of these GWAS results remains poorly understood. To address this issue, we created an expression quantitative trait loci (eQTL) atlas for the glomerular and tubular compartments of the human kidney. Through integrating the CKD GWAS with eQTL, single-cell RNA sequencing and regulatory region maps, we identified novel genes for CKD. Putative causal genes were enriched for proximal tubule expression and endolysosomal function, where DAB2, an adaptor protein in the TGF-ß pathway, formed a central node. Functional experiments confirmed that reducing Dab2 expression in renal tubules protected mice from CKD. In conclusion, compartment-specific eQTL analysis is an important avenue for the identification of novel genes and cellular pathways involved in CKD development and thus potential new opportunities for its treatment.


Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Genetic Predisposition to Disease , Quantitative Trait Loci/genetics , Renal Insufficiency, Chronic/genetics , Tumor Suppressor Proteins/genetics , Animals , Apoptosis Regulatory Proteins , Cell Compartmentation/genetics , Disease Models, Animal , Gene Expression Regulation/genetics , Genome-Wide Association Study , Humans , Kidney/metabolism , Kidney/pathology , Kidney Glomerulus/metabolism , Kidney Glomerulus/pathology , Kidney Tubules, Proximal/metabolism , Kidney Tubules, Proximal/pathology , Mice , Polymorphism, Single Nucleotide/genetics , Renal Insufficiency, Chronic/physiopathology , Signal Transduction/genetics , Transforming Growth Factor beta/genetics
13.
PLoS Biol ; 16(9): e2005233, 2018 09.
Article in English | MEDLINE | ID: mdl-30226866

ABSTRACT

While Notch signaling has been proposed to play a key role in fibrosis, the direct molecular pathways targeted by Notch signaling and the precise ligand and receptor pair that are responsible for kidney disease remain poorly defined. In this study, we found that JAG1 and NOTCH2 showed the strongest correlation with the degree of interstitial fibrosis in a genome-wide expression analysis of a large cohort of human kidney samples. Transcript analysis of mouse kidney disease models, including folic-acid (FA)-induced nephropathy, unilateral ureteral obstruction (UUO), or apolipoprotein L1 (APOL1)-associated kidney disease, indicated that Jag1 and Notch2 levels were higher in all analyzed kidney fibrosis models. Mice with tubule-specific deletion of Jag1 or Notch2 (Kspcre/Jag1flox/flox and Kspcre/Notch2flox/flox) had no kidney-specific alterations at baseline but showed protection from FA-induced kidney fibrosis. Tubule-specific genetic deletion of Notch1 and global knockout of Notch3 had no effect on fibrosis. In vitro chromatin immunoprecipitation experiments and genome-wide expression studies identified the mitochondrial transcription factor A (Tfam) as a direct Notch target. Re-expression of Tfam in tubule cells prevented Notch-induced metabolic and profibrotic reprogramming. Tubule-specific deletion of Tfam resulted in fibrosis. In summary, Jag1 and Notch2 play a key role in kidney fibrosis development by regulating Tfam expression and metabolic reprogramming.


Subject(s)
DNA-Binding Proteins/metabolism , High Mobility Group Proteins/metabolism , Jagged-1 Protein/metabolism , Kidney/metabolism , Kidney/pathology , Mitochondrial Proteins/metabolism , Receptor, Notch2/metabolism , Transcription Factors/metabolism , Animals , Cell Dedifferentiation , Cell Proliferation , Epithelial Cells/metabolism , Fibrosis , Gene Ontology , Genotype , Humans , Kidney Tubules/pathology , Male , Mice, Inbred C57BL , Mice, Knockout , Models, Biological , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Signal Transduction
14.
Proc Natl Acad Sci U S A ; 115(21): 5600-5605, 2018 05 22.
Article in English | MEDLINE | ID: mdl-29739889

ABSTRACT

Hypertonicity in renal medulla is critical for the kidney to produce concentrated urine. Renal medullary cells have to survive high medullary osmolarity during antidiuresis. Previous study reported that farnesoid X receptor (FXR), a nuclear receptor transcription factor activated by endogenous bile acids, increases urine concentrating ability by up-regulating aquaporin 2 expression in medullary collecting duct cells (MCDs). However, whether FXR is also involved in the maintenance of cell survival of MCDs under dehydration condition and hypertonic stress remains largely unknown. In the present study, we demonstrate that 24-hours water restriction selectively up-regulated renal medullary expression of FXR with little MCD apoptosis in wild-type mice. In contrast, water deprivation caused a massive apoptosis of MCDs in both global FXR gene-deficient mice and collecting duct-specific FXR knockout mice. In vitro studies showed that hypertonicity significantly increased FXR and tonicity response enhancer binding protein (TonEBP) expression in mIMCD3 cell line and primary cultured MCDs. Activation and overexpression of FXR markedly increased cell viability and decreased cell apoptosis under hyperosmotic conditions. In addition, FXR can increase gene expression and nuclear translocation of TonEBP. We conclude that FXR protects MCDs from hypertonicity-induced cell injury very likely via increasing TonEBP expression and nuclear translocation. This study provides insights into the molecular mechanism by which FXR enhances urine concentration via maintaining cell viability of MCDs under hyperosmotic condition.


Subject(s)
Kidney Concentrating Ability/physiology , Kidney Medulla/cytology , Kidney Tubules, Collecting/cytology , Osmotic Pressure/physiology , Receptors, Cytoplasmic and Nuclear/physiology , Stress, Physiological , Transcription Factors/metabolism , Animals , Gene Expression Regulation , Kidney Medulla/metabolism , Kidney Tubules, Collecting/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Transcription Factors/genetics
15.
Science ; 360(6390): 758-763, 2018 05 18.
Article in English | MEDLINE | ID: mdl-29622724

ABSTRACT

Our understanding of kidney disease pathogenesis is limited by an incomplete molecular characterization of the cell types responsible for the organ's multiple homeostatic functions. To help fill this knowledge gap, we characterized 57,979 cells from healthy mouse kidneys by using unbiased single-cell RNA sequencing. On the basis of gene expression patterns, we infer that inherited kidney diseases that arise from distinct genetic mutations but share the same phenotypic manifestation originate from the same differentiated cell type. We also found that the collecting duct in kidneys of adult mice generates a spectrum of cell types through a newly identified transitional cell. Computational cell trajectory analysis and in vivo lineage tracing revealed that intercalated cells and principal cells undergo transitions mediated by the Notch signaling pathway. In mouse and human kidney disease, these transitions were shifted toward a principal cell fate and were associated with metabolic acidosis.


Subject(s)
Cell Tracking/methods , Gene Expression Profiling/methods , Kidney Diseases/genetics , Kidney Tubules, Collecting/cytology , Kidney Tubules, Collecting/metabolism , Single-Cell Analysis/methods , Animals , Cell Plasticity , Genetic Markers , Humans , Mice , Receptors, Notch/metabolism , Sequence Analysis, RNA/methods , Signal Transduction
16.
Am J Hum Genet ; 100(6): 940-953, 2017 Jun 01.
Article in English | MEDLINE | ID: mdl-28575649

ABSTRACT

Chronic kidney disease (CKD) is a complex gene-environmental disease affecting close to 10% of the US population. Genome-wide association studies (GWASs) have identified sequence variants, localized to non-coding genomic regions, associated with kidney function. Despite these robust observations, the mechanism by which variants lead to CKD remains a critical unanswered question. Expression quantitative trait loci (eQTL) analysis is a method to identify genetic variation associated with gene expression changes in specific tissue types. We hypothesized that an integrative analysis combining CKD GWAS and kidney eQTL results can identify candidate genes for CKD. We performed eQTL analysis by correlating genotype with RNA-seq-based gene expression levels in 96 human kidney samples. Applying stringent statistical criteria, we detected 1,886 genes whose expression differs with the sequence variants. Using direct overlap and Bayesian methods, we identified new potential target genes for CKD. With respect to one of the target genes, lysosomal beta A mannosidase (MANBA), we observed that genetic variants associated with MANBA expression in the kidney showed statistically significant colocalization with variants identified in CKD GWASs, indicating that MANBA is a potential target gene for CKD. The expression of MANBA was significantly lower in kidneys of subjects with risk alleles. Suppressing manba expression in zebrafish resulted in renal tubule defects and pericardial edema, phenotypes typically induced by kidney dysfunction. Our analysis shows that gene-expression changes driven by genetic variation in the kidney can highlight potential new target genes for CKD development.


Subject(s)
Gene Expression Regulation , Genetic Variation , Kidney Diseases/genetics , Animals , Base Sequence , Gene Knockdown Techniques , Gene Regulatory Networks , Genome-Wide Association Study , Humans , Kidney/metabolism , Kidney/pathology , Kidney Diseases/pathology , Linkage Disequilibrium/genetics , Polymorphism, Single Nucleotide/genetics , Quantitative Trait Loci/genetics , Quantitative Trait, Heritable , Reproducibility of Results , Zebrafish/genetics , beta-Mannosidase/genetics
17.
Am J Physiol Renal Physiol ; 312(4): F619-F628, 2017 04 01.
Article in English | MEDLINE | ID: mdl-28052875

ABSTRACT

Liver X receptors (LXRs) including LXRα and LXRß are nuclear receptor transcription factors and play an important role in lipid and glucose metabolism. It has been previously reported that mice lacking LXRß but not LXRα develop a severe urine concentrating defect, likely via a central mechanism. Here we provide evidence that LXRß regulates water homeostasis through increasing aquaporin 2 (AQP2) protein levels in renal collecting ducts. LXRß-/- mice exhibited a reduced response to desmopressin (dDAVP) stimulation, suggesting that the diabetes insipidus phenotype is of both central and nephrogenic origin. AQP2 protein abundance in the renal inner medulla was significantly reduced in LXRß-/- mice but with little change in AQP2 mRNA levels. In vitro studies showed that AQP2 protein levels were elevated upon LXR agonist treatment in both primary cultured mouse inner medullary duct cells (mIMCD) and the mIMCD3 cell line with stably expressed AQP2. In addition, LXR agonists including TO901317 and GW3965 failed to induce AQP2 gene transcription but diminished its protein ubiquitination in primary cultured mIMCD cells, thereby inhibiting its degradation. Moreover, LXR activation-induced AQP2 protein expression was abolished by the protease inhibitor MG132 and the ubiquitination-deficient AQP2 (K270R). Taken together, the present study demonstrates that activation of LXRß increases AQP2 protein levels in the renal collecting ducts via a posttranscriptional mechanism. As such, LXRß represents a key regulator of body water homeostasis.


Subject(s)
Aquaporin 2/metabolism , Kidney Tubules, Collecting/metabolism , Liver X Receptors/metabolism , Protein Processing, Post-Translational , Animals , Antidiuretic Agents/pharmacology , Aquaporin 2/genetics , Cell Line , Deamino Arginine Vasopressin/pharmacology , Genotype , Kidney Concentrating Ability , Kidney Tubules, Collecting/drug effects , Liver X Receptors/deficiency , Liver X Receptors/drug effects , Liver X Receptors/genetics , Mice, Inbred C57BL , Mice, Knockout , Phenotype , Proteasome Endopeptidase Complex/metabolism , Protein Stability , Proteolysis , Time Factors , Transfection , Ubiquitination , Up-Regulation
18.
J Biol Chem ; 292(3): 837-846, 2017 01 20.
Article in English | MEDLINE | ID: mdl-27909050

ABSTRACT

Clear cell renal cell carcinoma (CCRCC) is an incurable malignancy in advanced stages and needs newer therapeutic targets. Transcriptomic analysis of CCRCCs and matched microdissected renal tubular controls revealed overexpression of NOTCH ligands and receptors in tumor tissues. Examination of the TCGA RNA-seq data set also revealed widespread activation of NOTCH pathway in a large cohort of CCRCC samples. Samples with NOTCH pathway activation were also clinically distinct and were associated with better overall survival. Parallel DNA methylation and copy number analysis demonstrated that both genetic and epigenetic alterations led to NOTCH pathway activation in CCRCC. NOTCH ligand JAGGED1 was overexpressed and associated with loss of CpG methylation of H3K4me1-associated enhancer regions. JAGGED2 was also overexpressed and associated with gene amplification in distinct CCRCC samples. Transgenic expression of intracellular NOTCH1 in mice with tubule-specific deletion of VHL led to dysplastic hyperproliferation of tubular epithelial cells, confirming the procarcinogenic role of NOTCH in vivo Alteration of cell cycle pathways was seen in murine renal tubular cells with NOTCH overexpression, and molecular similarity to human tumors was observed, demonstrating that human CCRCC recapitulates features and gene expression changes observed in mice with transgenic overexpression of the Notch intracellular domain. Treatment with the γ-secretase inhibitor LY3039478 led to inhibition of CCRCC cells in vitro and in vivo In summary, these data reveal the mechanistic basis of NOTCH pathway activation in CCRCC and demonstrate this pathway to a potential therapeutic target.


Subject(s)
Kidney Neoplasms/metabolism , Neoplasm Proteins/metabolism , Receptor, Notch1/metabolism , Signal Transduction , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid Precursor Protein Secretases/genetics , Amyloid Precursor Protein Secretases/metabolism , Animals , Carcinoma, Renal Cell , CpG Islands , DNA Methylation , DNA, Neoplasm/genetics , DNA, Neoplasm/metabolism , Female , Humans , Jagged-1 Protein/genetics , Jagged-1 Protein/metabolism , Kidney Neoplasms/drug therapy , Kidney Neoplasms/genetics , Kidney Neoplasms/pathology , Male , Mice , Neoplasm Proteins/antagonists & inhibitors , Neoplasm Proteins/genetics , Protease Inhibitors/pharmacology , Receptor, Notch1/genetics
19.
J Mol Cell Biol ; 8(6): 518-529, 2016 12.
Article in English | MEDLINE | ID: mdl-27436752

ABSTRACT

Among the four prostaglandin E2 receptors, EP3 receptor is the one most abundantly expressed in white adipose tissue (WAT). The mouse EP3 gene gives rise to three isoforms, namely EP3α, EP3ß, and EP3γ, which differ only at their C-terminal tails. To date, functions of EP3 receptor and its isoforms in WAT remain incompletely characterized. In this study, we found that the expression of all EP3 isoforms were downregulated in WAT of both db/db and high-fat diet-induced obese mice. Genetic ablation of three EP3 receptor isoforms (EP3-/- mice) or EP3α and EP3γ isoforms with EP3ß intact (EP3ß mice) led to an obese phenotype with increased food intake, decreased motor activity, reduced insulin sensitivity, and elevated serum triglycerides. Since the differentiation of preadipocytes and mouse embryonic fibroblasts to adipocytes was markedly facilitated by either pharmacological blockade or genetic deletion/inhibition of EP3 receptor via the cAMP/PKA/PPARγ pathway, increased adipogenesis may contribute to obesity in EP3-/- and EP3ß mice. Moreover, both EP3-/- and EP3ß mice had increased lipolysis in WAT mainly due to the activated cAMP/PKA/hormone-sensitive lipase pathway. Taken together, our findings suggest that EP3 receptor and its α and γ isoforms are involved in both adipogenesis and lipolysis and influence food intake, serum lipid levels, and insulin sensitivity.


Subject(s)
Adipogenesis , Adipose Tissue, White/metabolism , Lipolysis , Receptors, Prostaglandin E, EP3 Subtype/metabolism , Adipocytes/metabolism , Adipocytes/pathology , Animals , Cell Differentiation , Gene Deletion , Inflammation/metabolism , Inflammation/pathology , Insulin Resistance , Lipoproteins, VLDL/metabolism , Mice , Mice, Obese , Obesity/metabolism , Obesity/pathology , Phenotype , Protein Isoforms/metabolism , Rats, Sprague-Dawley , Signal Transduction , Triglycerides/metabolism
20.
Nat Rev Nephrol ; 12(7): 426-39, 2016 07.
Article in English | MEDLINE | ID: mdl-27140856

ABSTRACT

Kidney fibrosis is a common histological manifestation of functional decline in the kidney. Fibrosis is a reactive process that develops in response to excessive epithelial injury and inflammation, leading to myofibroblast activation and an accumulation of extracellular matrix. Here, we describe how three key developmental signalling pathways - Notch, Wnt and Hedgehog (Hh) - are reactivated in response to kidney injury and contribute to the fibrotic response. Although transient activation of these pathways is needed for repair of injured tissue, their sustained activation is thought to promote fibrosis. Excessive Wnt and Notch expression prohibit epithelial differentiation, whereas increased Wnt and Hh expression induce fibroblast proliferation and myofibroblastic transdifferentiation. Notch, Wnt and Hh are fundamentally different signalling pathways, but their choreographed activation seems to be just as important for fibrosis as it is for embryonic kidney development. Decreasing the activity of Notch, Wnt or Hh signalling could potentially provide a new therapeutic strategy to ameliorate the development of fibrosis in chronic kidney disease.


Subject(s)
Hedgehog Proteins/physiology , Kidney/pathology , Receptors, Notch/physiology , Signal Transduction/physiology , Wnt Signaling Pathway/physiology , Animals , Disease Models, Animal , Fibroblasts , Fibrosis/etiology , Homeostasis , Humans , Podocytes/physiology , Renal Insufficiency, Chronic/etiology
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