Unravelling the role of P4HB in skeletal development using zebrafish as a disease model

Abstract

Osteogenesis imperfecta (OI), commonly known as brittle bone disease, is a genetic disorder characterized by fragile bones and connective tissue abnormalities, primarily caused by mutations in collagen-related genes such as COL1A1 and COL1A2. Recent research has implicated the P4HB gene in OI, particularly in the Cole-Carpenter syndrome variant. This study aims to explain the role of P4HB in skeletal development using zebrafish as a model organism due to their genetic similarity to humans, transparency during embryonic development, and rapid reproduction. The research specifically investigates the differential expression of the genes sox9b and bmp2b in wild-type (WT) zebrafish compared to those with mutations in the P4HB gene, hypothesizing a reduction in expression levels in the mutated models. To test this hypothesis, a knock-in model of zebrafish with the P4HB mutation was developed, allowing for the assessment of gene function and expression. In-situ hybridization techniques were used to analyze the expression patterns of sox9b and bmp2b. These genes are integral to skeletal development and are thought to be affected by disruptions in P4HB function. The results showed no significant reduction in the expression of the sox9b genes in P4HB mutant zebrafish compared to WT, in comparison to the bmp2b mutant zebrafish that showed significant reduction in expression compared to the WT. These results suggest that the P4HB mutation, which disrupts type I collagen formation, may not have a major impact on the expression of sox9b and bmp2b which are involved in cartilage and bone development. This study enhances the understanding of the genetic mechanisms underlying OI and highlights the benefit of zebrafish as a model for studying skeletal diseases. The findings also emphasize the importance of P4HB in maintaining normal skeletal development, providing potential insights for therapeutic targets in treating conditions like OI.