Zhong Xingguo, Wu Feiyang, Gao Weicheng, Hu Jinlong, Shen Bing, Zhong Kaiyuan, Peng Junbin, Zhang Chong, Zhang Chao
Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, 230022 Hefei, Anhui, China.
Department of General Surgery, Anhui No. 2 Provincial People's Hospital, 230041 Hefei, Anhui, China.
Front Biosci (Landmark Ed). 2024 Nov 27;29(12):401. doi: 10.31083/j.fbl2912401.
Gallstone formation is a common digestive ailment, with unclear mechanisms underlying its development. Dysfunction of the gallbladder smooth muscle (GSM) may play a crucial role, particularly with a high-fat diet (HFD). This study aimed to investigate the effects of an HFD on GSM and assess how it alters contractility through changes in the extracellular matrix (ECM).
Guinea pigs and C57BL/6 mice were fed either an HFD or normal diet (ND). Primary cultures of their (guinea pigs) gallbladder smooth muscle cells (GSMCs) were used for experiments. Histological stains, RNA-sequencing, bioinformatics analysis, three-dimensional tissue culture, real-time polymerase chain reaction (PCR), Western blot, atomic force microscopy, and muscle tension measurements were performed.
Histological evidence indicated structural changes in the gallbladder muscle layer and ECM collagen deposition in the HFD group. The HFD group also showed increased expression of collagen, integrin family, and matrix metalloproteinase (MMP) and the phosphoinositide 3-kinase (PI3K)-protein kinase B (PKB/Akt) signaling pathway. Compared with GSMCs cultured on Matrigel containing 1 mg/mL of collagen I, those cultured with 2 mg/mL showed a phenotype change from contractile to synthetic cells. Consistent with these findings, the HFD group also demonstrated increased ECM stiffness and decreased smooth muscle contractility.
Our findings reveal a mechanism by which an HFD alters the ECM composition of the gallbladder muscle, activating the integrin/PI3K-Akt/MMP signaling pathway, thereby impacting GSMC phenotype and contractility. These insights enhance the understanding of gallstone formation mechanism and provide potential therapeutic targets to treat gallbladder dysfunction.
胆结石形成是一种常见的消化系统疾病，其发病机制尚不清楚。胆囊平滑肌（GSM）功能障碍可能起关键作用，尤其是在高脂饮食（HFD）情况下。本研究旨在探讨高脂饮食对胆囊平滑肌的影响，并评估其如何通过细胞外基质（ECM）的变化改变收缩性。
将豚鼠和C57BL/6小鼠分为高脂饮食组或正常饮食组（ND）。使用其（豚鼠）胆囊平滑肌细胞（GSMCs）的原代培养物进行实验。进行了组织学染色、RNA测序、生物信息学分析、三维组织培养、实时聚合酶链反应（PCR）、蛋白质印迹、原子力显微镜检查和肌肉张力测量。
组织学证据表明高脂饮食组胆囊肌层有结构变化和ECM胶原沉积。高脂饮食组还显示胶原蛋白、整合素家族、基质金属蛋白酶（MMP）以及磷酸肌醇3激酶（PI3K）-蛋白激酶B（PKB/Akt）信号通路的表达增加。与在含有1mg/mL I型胶原的基质胶上培养的GSMCs相比，在含有2mg/mL I型胶原的基质胶上培养的细胞表现出从收缩性细胞到合成性细胞的表型变化。与这些发现一致，高脂饮食组还表现出ECM硬度增加和平滑肌收缩性降低。
我们的研究结果揭示了一种机制，即高脂饮食改变胆囊肌肉的ECM组成，激活整合素/PI3K-Akt/MMP信号通路，从而影响GSMC表型和收缩性。这些见解增进了对胆结石形成机制的理解，并为治疗胆囊功能障碍提供了潜在的治疗靶点。
