Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai, 201306, China.
Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai, 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China.
Fish Shellfish Immunol. 2019 Jun;89:437-447. doi: 10.1016/j.fsi.2019.04.021. Epub 2019 Apr 11.
Proteinase inhibitors with the ability to inhibit specific proteinases are usually closely connected with the immune system. Interestingly, proteinase inhibitors are also a common ingredient in the organic matrix of mollusk shells. However, the molecular mechanism that underlies the role of proteinase inhibitors in immune system and shell mineralization is poorly known. In this study, a Kunitz serine proteinase inhibitor (HcKuPI) was isolated from the mussel Hyriopsis cumingii. HcKuPI was specifically expressed in dorsal epithelial cells of the mantle pallium and HcKuPI dsRNA injection caused an irregular surface and disordered deposition on the aragonite tablets of the nacreous layer. These results indicated that HcKuPI plays a vital role in shell nacreous layer biomineralization. Moreover, the expression pattern of HcKuPI during LPS challenge and pearl formation indicated its involvement in the antimicrobial process during pearl sac formation and nacre tablets accumulation during pearl formation. In the in vitro calcium carbonate crystallization assay, the addition of GST-HcKuPI increased the precipitation rate of calcium carbonate and induced the crystal overgrowth of calcium carbonate. Taken together, these results indicate that HcKuPI is involved in antimicrobial process during pearl formation, and participates in calcium carbonate deposition acceleration and morphological regulation of the crystals during nacreous layer formation. These findings extend our knowledge of the role of proteinase inhibitors in immune system and shell biomineralization.
具有抑制特定蛋白酶能力的蛋白酶抑制剂通常与免疫系统密切相关。有趣的是，蛋白酶抑制剂也是软体动物壳有机基质的常见成分。然而，蛋白酶抑制剂在免疫系统和壳矿化中作用的分子机制知之甚少。在这项研究中，从贻贝 Hyriopsis cumingii 中分离到一种 Kunitz 丝氨酸蛋白酶抑制剂（HcKuPI）。HcKuPI 特异性表达于套膜的背上皮细胞，HcKuPI dsRNA 注射导致珍珠层中文石片的表面不规则和无序沉积。这些结果表明 HcKuPI 在贝壳珍珠层生物矿化中起着至关重要的作用。此外，HcKuPI 在 LPS 挑战和珍珠形成过程中的表达模式表明，它参与了珍珠囊形成过程中的抗菌过程以及珍珠形成过程中文石片的积累。在体外碳酸钙结晶测定中，添加 GST-HcKuPI 增加了碳酸钙的沉淀速率，并诱导了碳酸钙晶体的过度生长。总之，这些结果表明 HcKuPI 参与了珍珠形成过程中的抗菌过程，并参与了碳酸钙的沉积加速和珍珠层形成过程中晶体的形态调节。这些发现扩展了我们对蛋白酶抑制剂在免疫系统和壳生物矿化中作用的认识。
