A Novel Amino Acid Substitution, Fibrinogen B?p.Pro234Leu, Associated with Hypofibrinogenemia Causing Impairment of Fibrinogen Assembly and Secretion.

ABSTRACT: We identified a novel heterozygous variant, B?p.Pro234Leu (fibrinogen Tokorozawa), which was suspected to be associated with hypofibrinogenemia. Therefore, we analyzed the assembly and secretion of this fibrinogen using Chinese hamster ovary (CHO) cells. To determine the impact on the synthesis and secretion of fibrinogen of the B?p.P234L and ?p.G242E substitutions, we established recombinant variant fibrinogen-producing CHO cell lines. Synthesis and secretion analyses were performed using an enzyme-linked immunosorbent assay (ELISA) and immunoblotting analysis with the established cell lines. In addition, we performed fibrin polymerization using purified plasma fibrinogen and in-silico analysis. Both B?p.P234L and ?p.G242E impaired the secretion and synthesis of fibrinogen. Moreover, immunoblotting analysis elucidated the mobility migration of the B?? complex in B?p.P234L. On the other hand, the fibrin polymerization of fibrinogen Tokorozawa was similar to that of normal fibrinogen. In-silico analysis revealed that the B?p.P234 residue is located in the contact region between the B? and ? chains and contacts ?p.G242 residue. The present study demonstrated that the B?p.P234L substitution resulted in hypofibrinogenemia by decreasing the assembly and secretion of fibrinogen. Therefore, there is a possibility that substitutions in the contact region between the B? and ? chains impact the assembly and secretion of fibrinogen.

SUBMITTER: Kaido T 

PROVIDER: S-EPMC7764081 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature