Project description:In this study, we use transcriptomic approaches, to delineate a non-coding TAPT1 mutation (c.1237-52G>A) resulting in a protein-null allele, that segregated with a congenital recessive disease recessive consisting of Osteogenesis Imperfecta (OI) and neonatal progeria.
Project description:In this study, we use transcriptomic approaches, to delineate a non-coding TAPT1 mutation (c.1237-52G>A) resulting in a protein-null allele, that segregated with a congenital recessive disease recessive consisting of Osteogenesis Imperfecta (OI) and neonatal progeria.
Project description:Osteogenesis Imperfecta is characterized by short stature however the cellular mechanisms behind this phenotype are unclear. We isolated tibial and femoral cartilage growth plate chondrocytes from postnatal day 5 wild type and Aga2 (a model of OI) mice and analyzed differential expression patterns using single cell RNA-seq
Project description:Osteogenesis imperfecta (OI) is most commonly caused by autosomal dominant mutations in genes encoding collagen type-I. Here, we test the hypothesis that modulation of the endoplasmic reticulum (ER) proteostasis network via the unfolded protein response (UPR) can improve the folding and secretion of the lethal osteogenesis imperfecta (OI)-causing G425S a1(I) variant. We show that specific induction of the UPR’s XBP1s transcriptional response enhances G425S a1(I) secretion up to ~300% of basal levels. Notably, the effect is selective – WT a1(I) secretion is unaltered by XBP1s. XBP1s pathway activation appears to post-translationally enhance the folding/assembly and secretion of G425S a1(I). Consistent with this notion, we find that the stable, triple-helical collagen-I secreted by XBP1s-activated G425S a1(I) patient fibroblasts includes a higher proportion of the mutant a1(I) polypeptide than the collagen-I secreted under basal ER proteostasis conditions.
Project description:Osteogenesis imperfecta (OI) is a serious genetic bone disorder characterized by congenital low bone mass, deformity and frequent fractures. Type XV OI is a moderate to severe form of skeletal dysplasia caused by WNT1 mutations. In this cohort study from southern China, we summarized the clinical phenotypes of patients with WNT1 mutations and found the proportion of type XV patients was around 10.3% (25 out of 243) with diverse phenotypic spectrums. Functional assays indicated that mutations of WNT1 significantly impaired its secretion and effective activity, leading to moderate to severe clinical manifestations, porous bone structure and enhanced osteoclastic activities. Analysis of proteomic data from human skeleton indicated that the expression of SOST was dramatically reduced in type XV patients. Single-cell transcriptome data generated from human tibia samples revealed aberrant differentiation trajectory of skeletal progenitors and impaired maturation of osteocytes, resulting in excessive CXCL12+ progenitors and abnormal cell populations with adipogenic characteristics. The integration of multi-omics data from human skeleton delineates how WNT1 regulates the differentiation and maturation of skeletal progenitors, which will provide a new direction for the treatment strategy of type XV osteogenesis imperfecta and relative low bone mass diseases such as early onset osteoporosis.
Project description:Osteogenesis is the process of bone formation and is modulated by multiple regulatory networks. With the rapid development of the epitranscriptomics field, RNA modifications and their reader, writer, and eraser (RWE) proteins are shown to be involved in the regulation of various biological processes. Few studies, however, were conducted to investigate the functions of RNA modifications and their RWE proteins in osteogenesis. By using a parallel-reaction monitoring (PRM)-based targeted proteomics method, we performed a comprehensive quantitative assessment of 154 epitranscriptomic RWE proteins during the time course of osteogenic differentiation of H9 human embryonic stem cells (ESCs). We found that approximately half of the 126 detected RWE proteins were downregulated during osteogenic differentiation, and they included mainly those proteins involved in RNA methylation and pseudouridine synthesis. Protein-protein interaction (PPI) network analysis revealed a high connectivity between the downregulated epitranscriptomic RWE proteins and osteogenesis-related proteins. Gene set enrichment analysis of previously published RNA-seq data from osteogenesis imperfecta patients suggested a potential role of METTL1, the top-ranked hub protein of downregulated RWE proteins, in osteogenesis through the cytokine network. Together, this is the first targeted profiling of epitranscriptomic RWE proteins during osteogenic differentiation of human ESCs and our work unveiled potential regulatory roles of these proteins in osteogenesis.
Project description:Scoliosis is a three-dimensional structural deformity of the spine, while the underlying pathogenesis is not fully uncovered. Osteogenesis imperfecta (OI), known as brittle bone disease, is a group of rare genetic disorder associated with osteopenia, deformity and scoliosis. Here we found the mutation in FKBP10 resulted in early onset of scoliosis via deleterious effects on collagen processing and osteoblast differentiation.
Project description:We performed shotgun proteomic analysis of human type I collagen purified from the culture medium of normal or osteogenesis imperfecta fibroblasts by LC-MS after trypsin digestion for identification of lysine glycosylation sites.