p300 and cAMP response element‐binding protein‐binding protein in skeletal muscle homeostasis, contractile function, and survival

Abstract

Background Reversible ε-amino acetylation of lysine residues regulates transcription as well as metabolic flux; however, roles for specific lysine acetyltransferases in skeletal muscle physiology and function are unknown. In this study, we investigated the role of the related acetyltransferases p300 and cAMP response element-binding protein-binding protein (CBP) in skeletal muscle transcriptional homeostasis and physiology in adult mice. Methods Mice with skeletal muscle-specific and inducible knockout of p300 and CBP (PCKO) were generated by crossing mice with a tamoxifen-inducible Cre recombinase expressed under the human α-skeletal actin promoter with mice having LoxP sites flanking exon 9 of the Ep300 and Crebbp genes. Knockout of PCKO was induced at 13-15 weeks of age via oral gavage of tamoxifen for 5 days to both PCKO and littermate control [wildtype (WT)] mice. Body composition, food intake, and muscle function were assessed on day 0 (D0) through 5 (D5). Microarray and tandem mass tag mass spectrometry analyses were performed to assess global RNA and protein levels in skeletal muscle of PCKO and WT mice.Results At D5 after initiating tamoxifen treatment, there was a reduction in body weight (À15%), food intake (À78%), stride length (À46%), and grip strength (À45%) in PCKO compared with WT mice. Additionally, ex vivo contractile function [tetanic tension (kPa)] was severely impaired in PCKO vs. WT mice at D3 (~70-80% lower) and D5 (~80-95% lower) and resulted in lethality within 1 week-a phenotype that is reversed by the presence of a single allele of either p300 or CBP. The impaired muscle function in PCKO mice was paralleled by substantial transcriptional alterations (3310 genes; false discovery rate < 0.1), especially in gene networks central to muscle contraction and structural integrity. This transcriptional uncoupling was accompanied by changes in protein expression patterns indicative of impaired muscle function, albeit to a smaller magnitude (446 proteins; fold-change > 1.25; false discovery rate < 0.1). Conclusions These data reveal that p300 and CBP are required for the control and maintenance of contractile function and transcriptional homeostasis in skeletal muscle and, ultimately, organism survival. By extension, modulating p300/CBP function may hold promise for the treatment of disorders characterized by impaired contractile function in humans.

KAT3-dependent acetylation of cell type-specific genes maintains neuronal identity in the adult mouse brain

“…Our experiments in astrocytes, analysis of KAT3 peaks in different tissues and previous observations in other cell types demonstrating that the combined loss of CBP and p300 causes impaired cell-type-specific transcription [30][31][32][33] , all support this view. Further supporting this model, a very recent study in mice with skeletal muscle-specific and inducible combined ablation of p300 and CBP revealed that the two proteins are also jointly required for the control and maintenance of contractile function and transcriptional homeostasis in skeletal muscle 60 . What may differ between cell types is the specific set of TFs that recruit the KAT3 proteins to cell-type-specific loci.…”

p300 or CBP is required for insulin-stimulated glucose uptake in skeletal muscle and adipocytes

“…We attributed this lack of effect to the well-documented compensatory actions of p300 and CBP that occur when only p300 or CBP is present ( 25 , 26 ). Thus, we interbred these individual knockout models to generate a p300 and CBP skeletal muscle–specific, tamoxifen-inducible, double-knockout mouse (referred to as PCKO), which we previously described ( 27 ). Because PCKO mice die 6–7 days after initiating tamoxifen treatment ( 27 ), in this study all experiments in PCKO mice and wild-type (WT) littermates were conducted at day 1 (D1), 3 (D3), or 5 (D5) after starting tamoxifen dosing.…”

“…Concurrently, we studied a separate cohort of PCKO mice with measures being made on D5 after initiating tamoxifen dosing; D5 was chosen as there was a robust abrogation of insulin-stimulated glucose uptake by skeletal muscle in PCKO mice at this timepoint. The CBP KO/p300 HZ and p300 KO/CBP HZ lines have been described previously (27).…”

“…The abundance of insulin signaling and GLUT4 exocytic translocation proteins is significantly 8 changed in PCKO muscle at D5 but not at D3 While PCKO muscle had significant changes in mRNA expression of insulin signaling and GLUT4 trafficking genes compared to WT muscle, this cannot adequately explain the insulin resistant phenotype in PCKO mice without considering the consequent changes in protein abundance. To address this, we mined publicly available quantitative proteomics data (PRIDE project: PXD015694) in muscle from D3 and D5 PCKO, and D5 WT mice, which we previously generated (27). The PCA demonstrates that PCKO mice at D5 have a clearly different protein abundance profile compared to WT mice, whilst PCKO mice at D3 cluster closer to WT mice (Figure 3E).…”

“…Studies were conducted in male and female mice on a C57BL/6J background and housed in a conventional facility with 12-h light/12-h dark cycle. Inducible, skeletal muscle-specific, p300 and CBP double knockout mice (PCKO), as well as mice with only one allele of either p300 (CBP KO/p300 HZ) or CBP (p300 KO/CBP HZ) in skeletal muscle, have been described previously (27). Respective floxed, but Cre negative, littermates were used as experimental controls for the mouse models; collectively, these mice are referred to as wild type (WT).…”