Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Kowloon Tong, Kowloon, Hong Kong SAR, PR China.
Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, PR China.
Sci Rep. 2018 May 8;8(1):7199. doi: 10.1038/s41598-018-25490-w.
In zebrafish, the role of matrix metalloproteinases (MMPs) in the inflammatory phase of heart regeneration following cryoinjury remains poorly understood. Here, we demonstrated an increase in MMP enzymatic activity and elevated expression of mmp9 and mmp13 in the injured area (IA) of hearts from as early as 1 day post-cryoinjury (dpc). Treatment with the broad-spectrum MMP inhibitor, GM6001, during the first week after cryoinjury resulted in impaired heart regeneration, as indicated by the larger scar and reduced numbers of proliferating cardiomyocytes. GM6001 also significantly reduced the number of leukocytes to the IA at 0.5 dpc to 4 dpc. Specific inhibition of both MMP-9 and MMP-13 also resulted in impaired regeneration and leukocyte recruitment. However, chemokine rescue with recombinant CXCL8 and CCL2 restored the recruitment of macrophages and the cardiac regenerative capability in GM6001-treated fish. MMP-9 and MMP-13 cleaved zebrafish CXCL8 at the same site, and the truncated form was more chemotactic than the intact form. In contrast, CCL2 did not have an MMP-9 or MMP-13 cleavage site. Together, these data suggest that MMPs might play a key role in the inflammatory phase of heart regeneration in zebrafish, by mediating leukocyte recruitment via the activation of chemokines.
在斑马鱼中，基质金属蛋白酶（MMPs）在冷冻损伤后心脏再生的炎症期的作用仍知之甚少。在这里，我们发现在冷冻损伤后 1 天（dpc），损伤区域（IA）的 MMP 酶活性增加，mmp9 和 mmp13 的表达水平升高。在冷冻损伤后第一周内用广谱 MMP 抑制剂 GM6001 处理，导致心脏再生受损，表现为疤痕更大，增殖性心肌细胞数量减少。GM6001 还显著减少了 0.5 dpc 至 4 dpc 时 IA 处白细胞的数量。同时抑制 MMP-9 和 MMP-13 也导致再生受损和白细胞募集减少。然而，用重组 CXCL8 和 CCL2 进行趋化因子挽救，恢复了 GM6001 处理的鱼中巨噬细胞的募集和心脏再生能力。MMP-9 和 MMP-13 在相同的位置切割斑马鱼 CXCL8，截短形式比完整形式更具趋化性。相比之下，CCL2 没有 MMP-9 或 MMP-13 切割位点。总之，这些数据表明 MMPs 可能通过激活趋化因子介导白细胞募集，在斑马鱼心脏再生的炎症期发挥关键作用。
