血管平滑肌细胞(VSMC)的巨噬细胞样转化是动脉粥样硬化(AS)进展的危险因素。转录因子同源异型盒A1(HOXA1)在分化和发育中起着功能作用。本研究旨在探讨HOXA1在VSMC转化中的作用,从而为AS发病的潜在机制提供证据。
将高脂饮食(HFD)喂养的载脂蛋白E基因敲除(ApoE-/-)小鼠作为体内模型来模仿AS,而1-棕榈酰-2-(5-氧代戊酰)-sn-甘油-3-磷酸胆碱(POV-PC)处理的VSMC用作体外模型。产生表达靶向HOXA1的短发夹RNA的重组腺相关病毒-1(AAV-1)载体,本文称为AAV1-shHOXA1,用于整个研究的功能丧失实验。
在AS小鼠的主动脉根部,脂质沉积严重,HOXA1表达高于正常饮食或HFD喂养的宽型小鼠。沉默HOXA1抑制AS诱导的体重增加,炎症反应,血清和肝脏脂质代谢紊乱和动脉粥样硬化斑块形成。此外,HOXA1敲低AS小鼠的病变显示VSMC向巨噬细胞样细胞的转分化较少,同时抑制krüppel样因子4(KLF4)和核因子(NF)-κBRelA(p65)的表达。体外实验一致证实,HOXA1敲低抑制脂质积累,POV-PC处理的VSMC到巨噬细胞的表型转换和炎症。机制研究进一步表明,HOXA1转录激活RelA和KLF4参与了VSMC的病理表现。
HOXA1通过调节NF-κBp65和KLF4调节VSMCs可塑性参与AS进展。HOXA1有可能成为AS的生物标志物或治疗靶标。
Macrophage-like transformation of vascular smooth muscle cells (VSMCs) is a risk factor of atherosclerosis (AS) progression. Transcription factor homeobox A1 (HOXA1) plays functional roles in differentiation and development. This study aims to explore the role of HOXA1 in
VSMC transformation, thereby providing evidence for the potential mechanism of AS pathogenesis.
High fat diet (HFD)-fed apolipoprotein E knockout (ApoE-/-) mice were applied as an in vivo model to imitate AS, while 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POV-PC)-treated VSMCs were applied as an in vitro model. Recombinant adeno-associated-virus-1 (AAV-1) vectors that express short-hairpin RNAs targeting HOXA1, herein referred as AAV1-shHOXA1, were generated for the loss-of-function experiments throughout the study.
In the aortic root of AS mice, lipid deposition was severer and HOXA1 expression was higher than the wide-type mice fed with normal diet or HFD. Silencing of HOXA1 inhibited the AS-induced weight gain, inflammatory response, serum and liver lipid metabolism disorder and atherosclerotic plaque formation. Besides, lesions from AS mice with HOXA1 knockdown showed less trans-differentiation of VSMCs to macrophage-like cells, along with a suppression of krüppel-like factor 4 (KLF4) and nuclear factor (NF)-κB RelA (p65) expression. In vitro experiments consistently confirmed that HOXA1 knockdown suppressed lipid accumulation,
VSMC-to-macrophage phenotypic switch and inflammation in POV-PC-treated VSMCs. Mechanism investigations further illustrated that HOXA1 transcriptionally activated RelA and KLF4 to participate in the pathological manifestations of VSMCs.
HOXA1 participates in AS progression by regulating VSMCs plasticity via regulation of NF-κB p65 and KLF4. HOXA1 has the potential to be a biomarker or therapeutic target for AS.