Project description:We address whether the functions of HDAC3 in skeletal muscle require its enzyme activity. By mutating the NCoR/SMRT corepressors in a knock-in mouse model named NS-DADm, we ablated the enzymatic activity of HDAC3 without affecting its protein levels. Compared to the control mice, skeletal muscles from NS-DADm mice showed lower force generation, enhanced fatigue resistance, enhanced fatty acid oxidation, reduced glucose uptake during exercise, upregulated expression of metabolic genes involved in branched-chain amino acids (BCAAs) catabolism, and aging-associated reduction in muscle mass, without changes in the muscle fiber type composition or mitochondrial protein content. These findings demonstrate that the metabolic function of HDAC3 in skeletal muscles requires its enzymatic activity.
Project description:We address the function of HDAC3 in skeletal muscle metabolism We performed HDAC3 ChIP-seq, RNA-seq, and GRO-seq in mouse muscles at different times of the day and compared between WT and HDAC3-depleted muscles.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:Histone deacetylase 3 (HDAC3) is unique among the HDAC superfamily of chromatin modifiers that silence transcription through enzymatic modification of histones, because interaction with nuclear receptor corepressors (NCoR1/2) is required for engagement of its catalytic activity. However, loss of HDAC3 also represses transcription. Here we report that, during lipopolysaccharide (LPS) activation of macrophages, the deacetylase activity of HDAC3 is selectively engaged at ATF3-bound enhancers that repress anti-inflammatory genes. By contrast, LPS-stimulated recruitment of HDAC3 to ATF2-bound sites without NCoR1/2 activates pro-inflammatory genes by a non-canonical mechanism whereby catalytically inactive HDAC3 stably interacts with p65. Consistent with this bimodal inflammatory modulation, deletion of HDAC3 in macrophages safeguards mice from lethal exposure to LPS, but this protection is not conferred by genetic or pharmacological abolition of HDAC3 catalytic activity. Thus, HDAC3 is a dichotomous transcriptional activator and repressor whose deacetylase-independent functions are critical in priming the innate immune system.
Project description:Chromatin modifiers play critical roles in epidermal development, but the functions of histone deacetylases in this context are poorly understood. We find that the Class I HDAC, HDAC3, is expressed broadly in embryonic epidermis, and is required for its orderly stepwise stratification. Stability of HDAC3 protein in vivo is reliant on NCoR and SMRT, which function redundantly in epidermal development. However, point mutations in the NCoR and SMRT Deacetylase Activating Domains, which are required for HDAC3’s enzymatic function, permit normal stratification, indicating that HDAC3’s roles in this context are independent of its histone deacetylase activity. HDAC3 functions both in conjunction with, and independent of, KLF4 to repress premature expression of different sets of terminal differentiation genes and suppresses expression of inflammatory cytokines through a RelA-dependent mechanism. These data identify HDAC3 as a hub coordinating multiple aspects of epidermal barrier acquisition. We used microarrays to determine transcriptional changes in Hdac3 deleted epidermis compared to control and Ncor1/Ncor2 deleted epidermis compared to control.
Project description:HDAC3 and HDAC8 are members of class I deacetylases involved in several biological mechanisms and represent a highly sought-after therapeutic target for drug development. It is historically challenging to develop selective deacetylase inhibitors due to their conserved catalytic domains. HDAC3 also has deacetylase-independent activity, which cannot be blocked by conventional enzymatic inhibitors. Recent advances in proteolysis-targeting chimeras (PROTACs) provides an opportunity to eliminate the whole protein selectively, abolishing both enzymatic and scaffolding functions. Here, we report a novel HDAC3/8 dual degrader YX968 that induces highly potent, rapid and selective degradation of both HDAC3 and HDAC8 without trigging pan-HDAC inhibitory effects. Unbiased quantitative proteomics experiments further confirmed its high selectivity. This dual-specific degrader specifically ablates cellular pathways attributed to HDAC3 and HDAC8 and exhibits high potency in killing cancer cells. YX968 represents a new probe for dissecting the complex biological functions of HDAC3 and HDAC8.
Project description:Chromatin modifiers play critical roles in epidermal development, but the functions of histone deacetylases in this context are poorly understood. We find that the Class I HDAC, HDAC3, is expressed broadly in embryonic epidermis, and is required for its orderly stepwise stratification. Stability of HDAC3 protein in vivo is reliant on NCoR and SMRT, which function redundantly in epidermal development. However, point mutations in the NCoR and SMRT Deacetylase Activating Domains, which are required for HDAC3’s enzymatic function, permit normal stratification, indicating that HDAC3’s roles in this context are independent of its histone deacetylase activity. HDAC3 functions both in conjunction with, and independent of, KLF4 to repress premature expression of different sets of terminal differentiation genes and suppresses expression of inflammatory cytokines through a RelA-dependent mechanism. These data identify HDAC3 as a hub coordinating multiple aspects of epidermal barrier acquisition.