Histone Deacetylase 3 Aggravates Type 1 Diabetes Mellitus by Inhibiting Lymphocyte Apoptosis Through the microRNA-296-5p/Bcl-xl Axis

Abstract

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease characterized by immune-mediated destruction of pancreatic beta-cells. Multiple microRNAs (miRNAs) have been implicated in T1DM pathogenesis. Although histone deacetylase 3 (HDAC3) has been reported to be involved in T1DM, the underlying mechanisms remain to be further elucidated. This study was designed to investigate the potential regulatory role of Hdac3 on T1DM progression. The expression of miR-296-5p and B-cell leukemia-XL (BCL-XL) was determined using RT-qPCR and Western blot assay in peripheral blood mononuclear cells (PBMCs) of patients with T1DM, tumor necrosis factor-α (TNF-α)-and cycloheximide (CHX)-induced cell model, and streptozotocin (STZ)-induced rat model. The binding affinity between miR-296-5p and Bcl-xl was verified by using dual-luciferase reporter gene assay, and the binding between Hdac3 and the promoter region of miR-296-5p was validated using chromatin immunoprecipitation assay. Western blot analysis and flow cytometry were conducted to assess the apoptotic events of lymphocytes. miR-296-5p expression was downregulated while BCL-XL expression was upregulated in PBMCs of patients with T1DM. An adverse correlation was identified between miR-296-5p and Bcl-xl in mouse TE15 B lymphocytes. Bcl-xl was further validated to be targeted and negatively regulated by miR-296-5p in 293 T cells. Hdac3 inhibited miR-296-5p expression by binding to its promoter region. The effects of overexpressed Hdac3 on lymphocyte apoptosis was counterweighed via downregulation of Bcl-xl or upregulation of miR-296-5p, the mechanism of which was further validated in a rat model of DM. Taken together, the Hdac3-mediated upregulation of Bcl-xl via inhibiting miR-296-5p promoter activity enhanced the antiapoptotic capacity of lymphocytes to accelerate the occurrence of T1DM.

Downregulated HDAC3 or up-regulated microRNA-296-5p alleviates diabetic retinopathy in a mouse model

“…Consistently, HDAC3 expression has also been validated to be heightened in diabetic mice with cerebral ischemia/reperfusion (I/R) [ 31 ]. As for miR-296-5p expression, it has been manifested that miR-296-5p levels are remarkably down-regulated in patients with type 1 diabetes mellitus [ 24 ]. Similarly, Favaro et al.…”

“…The INPUT was set as the endogenous reference. The promoter region-specific primer miR-296-5p was adopted to assess the binding between HDAC3 and miR-296-5p [ 23 , 24 ].…”

Genetic and Epigenetic Aspects of Type 1 Diabetes Mellitus: Modern View on the Problem

“…The apoptosis of β-cells underlies the progression of T1DM, and the anti-apoptotic protein BCL-XL plays one of the key roles in this process [99]. A study by Hu et al showed that HDAC3-mediated increase in BCL-XL expression through the negative regulation of the miR-296-5p gene promoter inhibits lymphocyte apoptosis, increasing the risk of T1DM development [100]. The examination of proinflammatory mediators such as COX-2 in monocytes showed an increase in the level of acetylated histone H4 in patients with T1DM [101].…”

Epigenetic regulation in metabolic diseases: mechanisms and advances in clinical study

“…HDAC3 could interact with miR-296-5p to elevate the expression of Bcl-xl, resulting in the enhancement of the antiapoptotic capacity in lymphocytes and thereby exacerbating type 1 diabetes (T1D). 186 As HATs and transcriptional co-activators, CBP and its paralogue p300 play critical roles in the β cell identity and functional maturity. By acetylating H3K27 and transcription factors, including FOXO1 and Hnf1α, CBP and p300 are responsible for T2D by regulating transcription.…”