Abonia J Pablo, Friend Daniel S, Austen William G, Moore Francis D, Carroll Michael C, Chan Rodney, Afnan Jalil, Humbles Alison, Gerard Craig, Knight Pamela, Kanaoka Yoshihide, Yasuda Shinsuke, Morokawa Nasa, Austen K Frank, Stevens Richard L, Gurish Michael F
Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA.
J Immunol. 2005 Jun 1;174(11):7285-91. doi: 10.4049/jimmunol.174.11.7285.
Ischemia with subsequent reperfusion (IR) injury is a significant clinical problem that occurs after physical and surgical trauma, myocardial infarction, and organ transplantation. IR injury of mouse skeletal muscle depends on the presence of both natural IgM and an intact C pathway. Disruption of the skeletal muscle architecture and permeability also requires mast cell (MC) participation, as revealed by the fact that IR injury is markedly reduced in c-kit defective, MC-deficient mouse strains. In this study, we sought to identify the pathobiologic MC products expressed in IR injury using transgenic mouse strains with normal MC development, except for the lack of a particular MC-derived mediator. Histologic analysis of skeletal muscle from BALB/c and C57BL/6 mice revealed a strong positive correlation (R(2) = 0.85) between the extent of IR injury and the level of MC degranulation. Linkage between C activation and MC degranulation was demonstrated in mice lacking C4, in which only limited MC degranulation and muscle injury were apparent. No reduction in injury was observed in transgenic mice lacking leukotriene C(4) synthase, hemopoietic PGD(2) synthase, N-deacetylase/N-sulfotransferase-2 (enzyme involved in heparin biosynthesis), or mouse MC protease (mMCP) 1. In contrast, muscle injury was significantly attenuated in mMCP-5-null mice. The MCs that reside in skeletal muscle contain abundant amounts of mMCP-5 which is the serine protease that is most similar in sequence to human MC chymase. We now report a cytotoxic activity associated with a MC-specific protease and demonstrate that mMCP-5 is critical for irreversible IR injury of skeletal muscle.
缺血再灌注（IR）损伤是一个严重的临床问题，发生于物理和外科创伤、心肌梗死及器官移植后。小鼠骨骼肌的IR损伤取决于天然IgM和完整补体（C）途径的存在。骨骼肌结构破坏和通透性增加也需要肥大细胞（MC）参与，c-kit缺陷、MC缺乏的小鼠品系中IR损伤明显减轻就证明了这一点。在本研究中，我们试图利用MC发育正常但缺乏特定MC衍生介质的转基因小鼠品系，来确定IR损伤中表达的病理生物学MC产物。对BALB/c和C57BL/6小鼠骨骼肌的组织学分析显示，IR损伤程度与MC脱颗粒水平之间存在强正相关（R(2) = 0.85）。在缺乏C4的小鼠中证实了补体激活与MC脱颗粒之间的联系（此类小鼠仅有有限的MC脱颗粒和肌肉损伤）。在缺乏白三烯C(4)合成酶、造血前列腺素D(2)合成酶、N-脱乙酰酶/N-磺基转移酶-2（参与肝素生物合成的酶）或小鼠MC蛋白酶（mMCP）1的转基因小鼠中未观察到损伤减轻。相比之下，mMCP-5基因敲除小鼠的肌肉损伤明显减轻。存在于骨骼肌中的MC含有大量mMCP-5，这是一种丝氨酸蛋白酶，其序列与人类MC糜蛋白酶最为相似。我们现在报告一种与MC特异性蛋白酶相关的细胞毒性活性，并证明mMCP-5对骨骼肌不可逆的IR损伤至关重要。
