Characterization of aortic carboxypeptidase-like protein mutations that cause Ehlers-Danlos syndrome

Date
2022
DOI
Authors
Ahmed, Sidrah
Version
Embargo Date
2025-02-06
OA Version
Citation
Abstract
Ehlers-Danlos Syndrome (EDS) is a hereditary connective tissue disease that can cause a wide range of symptoms throughout the body. There are currently 14 different subtypes of EDS based on the molecular genetics of the disease with many subtypes due to mutations in collagen genes. Classical-like Type 2 EDS is caused by mutations in aortic carboxypeptidase-like protein (ACLP), gene name AEBP1. ACLP plays important roles in collagen polymerization, vascular smooth muscle differentiation, and myofibroblast differentiation. There have been multiple ACLP mutations that have been implicated in EDS. Previous studies have shown an ACLP mutation Asn490_Met495delins, a mutation with intron inclusion in the protein, is intracellularly retained and causes endoplasmic reticulum (ER) stress. This study aims to characterize 5 additional human ACLP mutations that cause EDS including Leu642Pro, Asn236Ser, Trp356*, Cys581*, and Arg631* to determine how these proteins disrupt the extracellular matrix (ECM). To achieve this goal, plasmid vectors harboring the desired mutation were generated. Immunofluorescent imaging revealed all mutated proteins remained in the secretory pathway and were properly translocated to the endoplasmic reticulum (ER). Western blot of cell lysate and media sample from cells transfected with the generated plasmid revealed that Leu642Pro was intracellularly retained while Asn236Ser, Trp356*, Cys581*, and Arg631* were secreted from the cell into the extracellular environment. Additionally, ACLP knockout mouse models were generated to further study the role of ACLP in aortic dysfunction observed in some ACLP null EDS patients. These studies provide further information about the molecular mechanisms in which ACLP causes EDS that could be possible targets for intervention in the future.  
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