CAMP-induced nuclear condensation of CRTC2 promotes transcription elongation and cystogenesis in autosomal dominant polycystic kidney disease
Ontology highlight
ABSTRACT: Formation of biomolecular condensates by phase separation has recently emerged as a new principle for regulating gene expression in response to extracellular signaling. However, the molecular mechanisms underlying the coupling of signal transduction and gene activation through condensate formation, and how dysregulation of these mechanisms contributes to disease progression, remain elusive. Here we report that CREB-regulated transcription coactivator 2 (CRTC2) translocates to the nucleus and forms phase-separated condensates upon activation of cAMP signaling. We show that intranuclear CRTC2 interacts with positive transcription elongation factor b (P-TEFb) and activates P-TEFb by disrupting the inhibitory 7SK snRNP complex. Aberrantly elevated cAMP signaling plays central roles in the development of autosomal dominant polycystic kidney disease (ADPKD). We find that CRTC2 localizes to the nucleus and forms condensates in cystic epithelial cells of both mouse and human ADPKD kidneys. Genetic depletion of CRTC2 suppresses cyst growth in an orthologous ADPKD mouse model. Using integrative transcriptomic and cistromic analyses, we identify CRTC2-regulated cystogenesis-associated genes, whose activation depends on CRTC2 condensate-facilitated P-TEFb recruitment and the release of paused RNA polymerase II. Together, our findings elucidate a mechanism by which CRTC2 nuclear condensation conveys cAMP signaling to transcription elongation activation and thereby promotes cystogenesis in ADPKD.
Project description:Forming biomolecular condensates by phase separation has recently emerged as a new principle for regulating gene expression in response to extracellular signaling. However, the molecular mechanisms underlying the coupling of signaling transduction and gene activation through condensate formation and how dysregulation of these mechanisms contributes to disease progression remain elusive. Here we report that CREB-regulated transcription coactivator 2 (CRTC2) translocates to nucleus and forms phase-separated condensates upon activation of cAMP signaling. We show that CRTC2 interacts with positive transcription elongation factor b (P-TEFb), and cAMP-induced CRTC2 condensate formation activates P-TEFb by extracting P-TEFb from its inhibitory complex. Aberrantly elevated cAMP signaling plays central roles in the development of autosomal dominant polycystic kidney disease (ADPKD). We demonstrate that, in contrast to a dispersed cytosolic distribution in the normal tubular epithelia cells, CRTC2 localizes in nucleus and forms condensates in cystic epithelial cells of mouse and human ADPKD kidneys. We show that genetic depletion of CRTC2 markedly suppresses cyst growth in an orthologous ADPKD mouse model. Using integrative transcriptomic and cistromic analyses, we identify CRTC2-regulated cystogenic genes, whose activation depends on CRTC2 condensation-facilitated P-TEFb recruitment and RNA polymerase II pausing release. Together, our findings elucidate a mechanism by which CRTC2 nuclear condensation conveys cAMP signaling to transcription elongation activation and promotes cystogenesis in ADPKD.
Project description:Forming biomolecular condensates by phase separation has recently emerged as a new principle for regulating gene expression in response to extracellular signaling. However, the molecular mechanisms underlying the coupling of signaling transduction and gene activation through condensate formation and how dysregulation of these mechanisms contributes to disease progression remain elusive. Here we report that CREB-regulated transcription coactivator 2 (CRTC2) translocates to nucleus and forms phase-separated condensates upon activation of cAMP signaling. We show that CRTC2 interacts with positive transcription elongation factor b (P-TEFb), and cAMP-induced CRTC2 condensate formation activates P-TEFb by extracting P-TEFb from its inhibitory complex. Aberrantly elevated cAMP signaling plays central roles in the development of autosomal dominant polycystic kidney disease (ADPKD). We demonstrate that, in contrast to a dispersed cytosolic distribution in the normal tubular epithelia cells, CRTC2 localizes in nucleus and forms condensates in cystic epithelial cells of mouse and human ADPKD kidneys. We show that genetic depletion of CRTC2 markedly suppresses cyst growth in an orthologous ADPKD mouse model. Using integrative transcriptomic and cistromic analyses, we identify CRTC2-regulated cystogenic genes, whose activation depends on CRTC2 condensation-facilitated P-TEFb recruitment and RNA polymerase II pausing release. Together, our findings elucidate a mechanism by which CRTC2 nuclear condensation conveys cAMP signaling to transcription elongation activation and promotes cystogenesis in ADPKD.
Project description:We showed that pharmacological inhibition of P-TEFb attenuated cyst development in ADPKD mouse models. Genome-wide analyses demonstrated that P-TEFb inhibition abrogated transcriptional pause release and suppressed a pathologic gene expression program during cystogenesis. This work revealed a mechanism by which aberrant activation of P-TEFb-mediated transcription elongation promotes cystogenesis in ADPKD.
Project description:We showed that pharmacological inhibition of P-TEFb attenuated cyst development in ADPKD mouse models. Genome-wide analyses demonstrated that P-TEFb inhibition abrogated transcriptional pause release and suppressed a pathologic gene expression program during cystogenesis. This work revealed a mechanism by which aberrant activation of P-TEFb-mediated transcription elongation promotes cystogenesis in ADPKD.
Project description:Mitochondrial dysfunction is emerging as a crucial contributor to the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD), but the molecular mechanisms underlying the disturbed mitochondrial homeostasis in cystic cells remain elusive. In the present study, we identify impaired activity of NRF2 antioxidant pathway as a driver mechanism for mitochondrial dysfunction and ADPKD progression. Using a quantitative proteomic approach, we find that NRF2 antioxidant pathway is suppressed in ADPKD kidneys. In a cohort of ADPKD patients, reactive oxygen species (ROS) levels are frequently elevated, and the increased ROS levels inversely correlates with decreased NRF2 expression and positively correlates with disease severity. Genetic deletion of NRF2 increases ROS generation and promotes cyst growth in an orthologous ADPKD mouse model, while pharmacological induction of NRF2 reduces ROS levels and retards cystogenesis and disease progression. Mechanistically, NRF2 activates its antioxidant target genes mainly through remodeling enhancer landscapes. The activation domain of NRF2 forms phase-separated condensates with MED16, a Mediator complex subunit in vitro, and NRF2 is required for optimal Mediator recruitment to target genomic sites in vivo. Taken together, these findings indicate that NRF2 remodels enhancer landscapes and activates its target genes through a phase-separation mechanism, and that activation of NRF2 represents a promising strategy for restoring mitochondrial homeostasis and combatting ADPKD.
Project description:Oxidative stress is emerging as a crucial contributor to the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD), but the molecular mechanisms underlying the disturbed redox homeostasis in cystic cells remain elusive. In the present study, we identify impaired activity of Nrf2 antioxidant pathway as a driver mechanism for oxidative damage and ADPKD progression. Using a quantitative proteomic approach, together with biochemistry analyses, we find that Nrf2 antioxidant pathway is suppressed due to increased degradation of Nrf2 protein in ADPKD kidneys. In a cohort of ADPKD patients, reactive oxygen species (ROS) levels are frequently elevated, and the ROS levels inversely correlates with Nrf2 abundance and positively correlates with disease severity. Genetic deletion of Nrf2 further increases ROS generation and promotes cyst growth in an orthologous ADPKD mouse model, while pharmacological induction of Nrf2 reduces ROS levels and retards cystogenesis and disease progression. Mechanistically, pharmacological induction of Nrf2 remodels enhancer landscapes and activates Nrf2-bound enhancer-associated genes in ADPKD cells. The activation domain of Nrf2 forms phase-separated condensates with Mediator subunit MED16 in vitro, and Nrf2 is required for optimal Mediator recruitment to target genomic loci in vivo. Taken together, these findings indicate that Nrf2 remodels enhancer landscapes and activates its target genes through a phase-separation mechanism, and that activation of Nrf2 represents a promising strategy for restoring redox homeostasis and combatting ADPKD.
Project description:Oxidative stress is emerging as a crucial contributor to the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD), but the molecular mechanisms underlying the disturbed redox homeostasis in cystic cells remain elusive. In the present study, we identify impaired activity of Nrf2 antioxidant pathway as a driver mechanism for oxidative damage and ADPKD progression. Using a quantitative proteomic approach, together with biochemistry analyses, we find that Nrf2 antioxidant pathway is suppressed due to increased degradation of Nrf2 protein in ADPKD kidneys. In a cohort of ADPKD patients, reactive oxygen species (ROS) levels are frequently elevated, and the ROS levels inversely correlates with Nrf2 abundance and positively correlates with disease severity. Genetic deletion of Nrf2 further increases ROS generation and promotes cyst growth in an orthologous ADPKD mouse model, while pharmacological induction of Nrf2 reduces ROS levels and retards cystogenesis and disease progression. Mechanistically, pharmacological induction of Nrf2 remodels enhancer landscapes and activates Nrf2-bound enhancer-associated genes in ADPKD cells. The activation domain of Nrf2 forms phase-separated condensates with Mediator subunit MED16 in vitro, and Nrf2 is required for optimal Mediator recruitment to target genomic loci in vivo. Taken together, these findings indicate that Nrf2 remodels enhancer landscapes and activates its target genes through a phase-separation mechanism, and that activation of Nrf2 represents a promising strategy for restoring redox homeostasis and combatting ADPKD.