摘要: Objectives Recent studies revealed LRRC8A to be an essential component of volume-regulated anion channel (VRAC), which regulates cellular volume homeostasis. However, evidence for the contribution of LRRC8A-dependent VRAC activity in vascular smooth muscle cells (VSMCs) is still lacking, and the relevant functional role of LRRC8A in VSMCs remains unknown. The primary goal of this study was to elucidate the role of LRRC8A in VRAC activity in VSMCs and the functional role of LRRC8A in cerebrovascular remodeling during hypertension. Materials and Methods siRNA-mediated knockdown and adenovirus-mediated overexpression of LRRC8A were used to elucidate the electrophysiological properties of LRRC8A in basilar smooth muscle cells (BASMCs). A smooth muscle-specific overexpressing transgenic mouse model was used to investigate the functional role of LRRC8A in cerebrovascular remodeling. Results LRRC8A is essential for volume-regulated chloride current (I-Cl,I- Vol) in BASMCs. Overexpression of LRRC8A induced a voltage-dependent Cl- current independently of hypotonic stimulation. LRRC8A regulated BASMCs proliferation through activation of WNK1/PI3K-p85/AKT axis. Smooth muscle-specific upregulation of LRRC8A aggravated Angiotensin II-induced cerebrovascular remodeling in mice. Conclusions LRRC8A is an essential component of VRAC and is required for cell volume homeostasis during osmotic challenge in BASMCs. Smooth muscle specific overexpression of LRRC8A increases BASMCs proliferation and substantially aggravates basilar artery remodeling, revealing a potential therapeutic target for vascular remodeling in hypertension.

摘要: Objectives Cutaneous wound healing is one of the major medical problems worldwide. Epigenetic modifiers have been identified as important players in skin development, homeostasis and wound repair. SET domain-containing 2 (SETD2) is the only known histone H3K36 tri-methylase; however, its role in skin wound healing remains unclear. Materials and Methods To elucidate the biological role of SETD2 in wound healing, conditional gene targeting was used to generate epidermis-specific Setd2-deficient mice. Wound-healing experiments were performed on the backs of mice, and injured skin tissues were collected and analysed by haematoxylin and eosin (H&E) and immunohistochemical staining. In vitro, CCK8 and scratch wound-healing assays were performed on Setd2-knockdown and Setd2-overexpression human immortalized keratinocyte cell line (HaCaT). In addition, RNA-seq and H3K36me3 ChIP-seq analyses were performed to identify the dysregulated genes modulated by SETD2. Finally, the results were validated in functional rescue experiments using AKT and mTOR inhibitors (MK2206 and rapamycin). Results Epidermis-specific Setd2-deficient mice were successfully established, and SETD2 deficiency resulted in accelerated re-epithelialization during cutaneous wound healing by promoting keratinocyte proliferation and migration. Furthermore, the loss of SETD2 enhanced the scratch closure and proliferation of keratinocytes in vitro. Mechanistically, the deletion of Setd2 resulted in the activation of AKT/mTOR signalling pathway, while the pharmacological inhibition of AKT and mTOR with MK2206 and rapamycin, respectively, delayed wound closure. Conclusions Our results showed that SETD2 loss promoted cutaneous wound healing via the activation of AKT/mTOR signalling.