Institute for Anatomy and Cell Biology, Department of Medical Cell Biology, University of Marburg, 35032, Marburg, Germany.
Section on Molecular Neuroscience, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health Intramural Research Program, Bethesda, MD, 20814, USA.
BMC Cardiovasc Disord. 2023 Nov 18;23(1):566. doi: 10.1186/s12872-023-03600-5.
Induction of chondrogenesis is associated with progressive atherosclerosis. Deficiency of the ADCYAP1 gene encoding pituitary adenylate cyclase-activating peptide (PACAP) aggravates atherosclerosis in ApoE deficient (ApoE) mice. PACAP signaling regulates chondrogenesis and osteogenesis during cartilage and bone development. Therefore, this study aimed to decipher whether PACAP signaling is related to atherogenesis-related chondrogenesis in the ApoE mouse model of atherosclerosis and under the influence of a high-fat diet.
For this purpose, PACAP/ApoE, PAC1/ApoE, and ApoE mice, as well as wildtype (WT) mice, were studied under standard chow (SC) or cholesterol-enriched diet (CED) for 20 weeks. The amount of cartilage matrix in atherosclerotic lesions of the brachiocephalic trunk (BT) with maximal lumen stenosis was monitored by alcian blue and collagen II staining on deparaffinized cross sections. The chondrogenic RUNX family transcription factor 2 (RUNX2), macrophages [(MΦ), Iba1], and smooth muscle cells (SMC, sm-α-actin) were immunohistochemically analyzed and quantified.
ApoE mice fed either SC or CED revealed an increase of alcian blue-positive areas within the media compared to WT mice. PAC1/ApoE mice under CED showed a reduction in the alcian blue-positive plaque area in the BT compared to ApoE mice. In contrast, PACAP deficiency in ApoE mice did not affect the chondrogenic signature under either diet.
Our data show that PAC1 deficiency reduces chondrogenesis in atherosclerotic plaques exclusively under conditions of CED-induced hypercholesterolemia. We conclude that CED-related chondrogenesis occurs in atherosclerotic plaques via transdifferentiation of SMCs and MΦ, partly depending on PACAP signaling through PAC1. Thus, PAC1 antagonists or PACAP agonists may offer therapeutic potential against pathological chondrogenesis in atherosclerotic lesions generated under hypercholesterolemic conditions, especially in familial hypercholesterolemia. This discovery opens therapeutic perspectives to be used in the treatment against the progression of atherosclerosis.
软骨形成的诱导与进行性动脉粥样硬化有关。编码垂体腺苷酸环化酶激活肽（PACAP）的 ADCYAP1 基因缺失会加重载脂蛋白 E 缺陷（ApoE）小鼠的动脉粥样硬化。PACAP 信号在软骨和骨骼发育过程中调节软骨形成和骨形成。因此，本研究旨在阐明 PACAP 信号是否与 ApoE 小鼠动脉粥样硬化模型中的动脉粥样硬化相关软骨形成有关，以及在高脂肪饮食的影响下是否与动脉粥样硬化相关软骨形成有关。
为此，在标准饮食（SC）或富含胆固醇饮食（CED）下研究了 PACAP/ApoE、PAC1/ApoE 和 ApoE 小鼠以及野生型（WT）小鼠 20 周。用阿尔辛蓝和脱蜡切片上的 II 型胶原蛋白染色监测肱动脉（BT）最大管腔狭窄处动脉粥样硬化病变中软骨基质的含量。用免疫组织化学分析和定量检测软骨形成 RUNX 家族转录因子 2（RUNX2）、巨噬细胞[（MΦ）、Iba1]和平滑肌细胞（SMC，sm-α-肌动蛋白）。
无论饮食如何，ApoE 小鼠的 BT 中层中的阿尔辛蓝阳性区域均高于 WT 小鼠。CED 下的 PAC1/ApoE 小鼠的 BT 中阿尔辛蓝阳性斑块面积较 ApoE 小鼠减少。相反，ApoE 小鼠中 PACAP 的缺失在两种饮食下均不影响软骨形成特征。
我们的数据表明，PAC1 缺乏可减少 CED 诱导的高胆固醇血症下动脉粥样硬化斑块中的软骨形成。我们得出结论，CED 相关的软骨形成发生在动脉粥样硬化斑块中，通过 SMC 和 MΦ 的转分化，部分依赖于 PACAP 通过 PAC1 的信号。因此，PAC1 拮抗剂或 PACAP 激动剂可能为治疗高胆固醇血症条件下产生的动脉粥样硬化病变中的病理性软骨形成提供治疗潜力，尤其是在家族性高胆固醇血症中。这一发现为治疗动脉粥样硬化的进展提供了治疗前景。
