H19 inhibition increases HDAC6 and regulates IRS1 levels and insulin signaling in the skeletal muscle during diabetes

Abstract

Background Histone deacetylases (HDACs) that catalyze removal of acetyl groups from histone proteins, are strongly associated with several diseases including diabetes, yet the precise regulatory events that control the levels and activity of the HDACs are not yet well elucidated. Methods Levels of H19 and HDACs were evaluated in skeletal muscles of normal and diabetic db/db mice by Western Blot analysis. C2C12 cells were differentiated and transfected with either the scramble or H19 siRNA and the levels of HDACs and Prkab2, Pfkfb3, Srebf1, Socs2, Irs1 and Ppp2r5b were assessed by Western Blot analysis and qRT-PCR, respectively. Levels of H9, HDAC6 and IRS1 were evaluated in skeletal muscles of scramble/ H19 siRNA injected mice and chow/HFD-fed mice. Results Our data show that the lncRNA H19 and HDAC6 exhibit inverse patterns of expression in the skeletal muscle of diabetic db/db mice and in C2C12 cells, H19 inhibition led to significant increase in HDAC activity and in the levels of HDAC6, both at the transcript and protein levels. This was associated with downregulation of IRS1 levels that were prevented in the presence of the HDAC inhibitor, SAHA, and HDAC6 siRNA suggesting the lncRNA H19-HDAC6 axis possibly regulates cellular IRS1 levels. Such patterns of H19, HDAC6 and IRS1 expression were also validated and confirmed in high fat diet-fed mice where as compared to normal chow-fed mice, H19 levels were significantly inhibited in the skeletal muscle of these mice and this was accompanied with elevated HDAC6 levels and decreased IRS1 levels. In-vivo inhibition of H19 led to significant increase in HDAC6 levels and this was associated with a decrease in IRS1 levels in the skeletal muscle. Conclusions Our results suggest a critical role for the lncRNA H19-HDAC6 axis in regulating IRS1 levels in the skeletal muscle during diabetes and therefore restoring normal H19 levels might hold a therapeutic potential for the management of aberrant skeletal muscle physiology during insulin resistance and type 2 diabetes.

Histone deacetylase functions and therapeutic implications for adult skeletal muscle metabolism

“…Upon fasting, HDAC6 deletion results in extensive mitochondrial degeneration due to a defect in mitochondrial fusion ( Lee et al, 2014 ). In diabetic mice, HDAC6 expression in skeletal muscle is upregulated, and impairs insulin signaling by downregulating Insulin Receptor Substrate 1 (IRS1) levels ( Kumar and Datta, 2022 ). This study provided further evidence that HDAC6 plays an important role in muscle metabolism.…”

“…SIRT1 and SIRT3 are the most studied sirtuins in muscle metabolism. Regardless of age, regular exercise increases the activity and expression of SIRT1 and 3, thus improving the efficiency of oxidative metabolism and mitochondrial biogenesis and function ( Boily et al, 2008 ; Lee et al, 2014 ; Kumar and Datta, 2022 ). Despite this general consideration, the effect of exercise on SIRT1 and 3 in human skeletal muscle depends on the type of exercise ( Vargas-Ortiz et al, 2019 ).…”

“…The pan-HDACi sodium butyrate improves HFD-induced obesity and insulin resistance in mice, by activating PGC-1alpha and AMPK ( Gao et al, 2009 ), and promoting the transcription of the IRS1 gene ( Chriett et al, 2017 ), thereby increasing glucose uptake, mitochondriogenesis and energy expenditure in skeletal muscle. Interestingly, IRS1 has also been identified as a target of HDAC6, and its modulation by the pan-HDACi SAHA rescues diabetic (db/db) or HFD-induced obesity in mice ( Kumar and Datta, 2022 ).…”

LncRNA H19 inhibition impairs endoplasmic reticulum-mitochondria contact in hepatic cells and augments gluconeogenesis by increasing VDAC1 levels

“…H19 is highly expressed in the skeletal muscle and H19 knockdown increases the myoblast-inhibitory genes Sirt1/FoxO1 during myogenesis and differentiation of bovine skeletal muscle satellite cells [ 70 ]. In C2C12 cells, H19 inhibition has been shown to dampen insulin-stimulated IRS1 and Akt phosphorylation [ 71 ] and by targeting hnRNPA, H19 promotes fatty acids oxidation and ameliorates skeletal muscle insulin resistance [ 72 ]. H19 expression is decreased in the muscles of insulin-resistant human subjects and high-fat diet fed rodents and mice with genetic H19 ablation exhibit muscle insulin resistance.…”

Shift work promotes adipogenesis via cortisol-dependent downregulation of EGR3-HDAC6 pathway

“…This indicates that HDAC6 could affect the metabolism of whole body and substantiated the HDAC6 is important regulator of adipose tissue [ 32 ]. Mice with specific depletion of hdac6 in adipose showed elevated lipid storage and insulin resistant [ 33 , 34 ]. EGR3 has been reported to bind to the promoter of HDAC6 to promote its expression [ 35 ].…”