Lysophosphatidic Acid經由Gi蛋白相關路徑在人類內皮細胞促使Membrane Type-1 Metalloproteinase之表現

Lysophosphatidic Acid Up-regulates MT1-MMP Expression through a Gi –dependent Pathway in Human Umbilical Vein Endothelial Cells

Lysophosphatidic acid（LPA）是小分子量的水解磷酸脂。LPA藉由接合到專一的G蛋白受器影響許多細胞的功能，包括細胞增生、細胞遷移、細胞入侵和細胞分化。Matrix-metalloproteinases（MMPs）是一群需要鋅離子才有活性的蛋白酶，MMPs在細胞和細胞基質間（Extracellular matrix, ECM）的交互作用中扮演著重要的角色。再者，membrane type 1-metalloproteinase（MT1-MMP）不只切除ECM也會幫助metalloproteinase-2（MMP-2,Gelatinase A）的活化，MMP-2已被證實在細胞遷移中扮演著重要的角色。我們之前的研究指出LPA會促進MMP-2在人類臍帶靜脈內皮細胞（Human umbilical vein endothelial cells, HUVECs）中的表現以及活性。在這份研究中，利用即時聚合酶放大技術（real-time PCR）以及西方點墨法（Western blotting），我們進一步發現LPA也會在HUVECs中促使MT1-MMP的訊息核醣核酸以及蛋白質表現增加。再者，藉由使用一些化學抑制物，我們發現LPA促使MT1-MMP的表現增加主要是經由Gi路徑，且部分經由Gq。這結果提供了LPA可能經由調節MT1-MMP的表現來調控ECM的新證據。

Lysophosphatidic acid (LPA) is a low molecular weight lysophospholipid (LPL). Through binding to its specific G protein-coupled receptor family, LPA regulates various cellular functions, including proliferation, migration, invasion, and differentiation. Matrix-metalloproteinases (MMPs) are zinc-dependent protease and play important roles in regulating the interaction between cells and extracellular matrix (ECM). Among these MMPs, membrane type 1-metalloproteinase (MT1-MMP) not only degrades ECM protein but also activates metalloproteinase-2 (MMP-2, Gelatinase A), which are important to endothelial cell migration. Our previous study showed that LPA enhances MMP-2 expression and activity in human umbilical vein endothelial cells (HUVECs). In this study, we further revealed that LPA also induce MT1-MMP mRNA and protein expressions in HUVECs through real-time PCR and Western blotting, respectively. Furthermore, by applying chemical inhibitors, we found that LPA-induced MT1-MMP expression is mainly through a Gi- and partially through a Gq-dependent pathway. Our results provide new evidence that LPA might modulate ECM through regulating the expression of MT1-MMP.