The Roles of Matrix Metalloproteinases in Anterior Regeneration in Aeolosoma viride

Abstract

Matrix metalloproteinases (MMPs) play key roles in turnover of extracellular matrix (ECM) and serve as important regulators of cell‐ECM interaction during development and regeneration. In previous studies, MMP‐2, MMP‐9 and MMP‐14 are found involved in regenerative processes in vertebrates. However, in invertebrates, no MMP‐2 or MMP‐9 has been found. So, the function of MMPs in the regenerative ability of invertebrates is an interesting question. In this research, a fresh water annelid, Aeolosoma viride, with high regenerative ability, was used to solve out this question. In the NGS transcriptome data of A. viride, only four matrix metalloproteinases, named as AviMMP1, AviMMP2, AviMTMMP1 and AviMTMMP2, were found. GM6001, MMPs inhibitor, had been treated during regeneration in A. viride and found that inhibiting MMPs activities at the early stage of anterior regeneration could delay the whole regenerative process, which means MMPs play some roles at the early stage of regeneration. The sequences of MMPs had been cloned and, in phylogenetic tree, they grouped with MMPs of other species. The qPCR data of blastema at different regenerative time point showed that Avimmp2 and Avimtmmp2 expressed highly at the early stage of anterior regeneration, but Avimmp1 and Avimtmmp1 showed no differences in expression during anterior regeneration. In situ hybridization analysis also indicated that high expression of Avimmp2 in blastema at 12, 24 and 48 hours post amputation (hpa). These data suggested that the AviMMP2 might be involved in the early stage of regeneration. On the other hand, SDS‐PAGE gelatin zymography showed the highest protease activity at 24 hpa blastema. These data suggested that MMPs have some effects on early stage of anterior regeneration, and AviMTMMP2 and AviMMP2 might be the key factors in the processes. The relationship between MMPs and the regulation of MMPs need further research to resolve.