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Matrix Biology : Journal of the... Aug 2023Osteogenesis imperfecta (OI) is a family of rare heritable skeletal disorders associated with dominant mutations in the collagen type I encoding genes and recessive...
Cell differentiation and matrix organization are differentially affected during bone formation in osteogenesis imperfecta zebrafish models with different genetic defects impacting collagen type I structure.
Osteogenesis imperfecta (OI) is a family of rare heritable skeletal disorders associated with dominant mutations in the collagen type I encoding genes and recessive defects in proteins involved in collagen type I synthesis and processing and in osteoblast differentiation and activity. Historically, it was believed that the OI bone phenotype was only caused by abnormal collagen type I fibrils in the extracellular matrix, but more recently it became clear that the altered bone cell homeostasis, due to mutant collagen retention, plays a relevant role in modulating disease severity in most of the OI forms and it is correlated to impaired bone cell differentiation. Despite in vitro evidence, in vivo data are missing. To better understand the physiopathology of OI, we used two zebrafish models: Chihuahua (Chi/+), carrying a dominant p.G736D substitution in the α1 chain of collagen type I, and the recessive p3h1, lacking prolyl 3-hydroxylase (P3h1) enzyme. Both models share the delay of collagen type I folding, resulting in its overmodification and partial intracellular retention. The regeneration of the bony caudal fin of Chi/+ and p3h1 was employed to investigate the impact of abnormal collagen synthesis on bone cell differentiation. Reduced regenerative ability was evident in both models, but it was associated to impaired osteoblast differentiation and osteoblastogenesis/adipogenesis switch only in Chi/+. On the contrary, reduced osteoclast number and activity were found in both models during regeneration. The dominant OI model showed a more detrimental effect in the extracellular matrix organization. Interestingly, the chemical chaperone 4-phenylbutyrate (4-PBA), known to reduce cellular stress and increase collagen secretion, improved bone formation only in p3h1 by favoring caudal fin growth without affecting bone cell markers expression. Taken together, our in vivo data proved the negative impact of structurally abnormal collagen type I on bone formation but revealed a gene mutation-specific effect on bone cell differentiation and matrix organization in OI. These, together with the distinct ability to respond to the chaperone treatment, underline the need for precision medicine approaches to properly treat the disease.
Topics: Animals; Collagen Type I; Osteogenesis Imperfecta; Osteogenesis; Zebrafish; Collagen; Molecular Chaperones; Mutation; Cell Differentiation
PubMed: 37336269
DOI: 10.1016/j.matbio.2023.06.003 -
Bone Oct 2023Diastrophic dysplasia (DTD) is a recessive chondrodysplasia caused by pathogenic variants in the SLC26A2 gene encoding for a cell membrane sulfate/chloride antiporter...
Diastrophic dysplasia (DTD) is a recessive chondrodysplasia caused by pathogenic variants in the SLC26A2 gene encoding for a cell membrane sulfate/chloride antiporter crucial for sulfate uptake and glycosaminoglycan (GAG) sulfation. Research on a DTD animal model has suggested possible pharmacological treatment approaches. In view of future clinical trials, the identification of non-invasive biomarkers is crucial to assess the efficacy of treatments. Urinary GAG composition has been analyzed in several metabolic disorders including mucopolysaccharidoses. Moreover, the N-terminal fragment of collagen X, known as collagen X marker (CXM), is considered a real-time marker of endochondral ossification and growth velocity and was studied in individuals with achondroplasia and osteogenesis imperfecta. In this work, urinary GAG sulfation and blood CXM levels were investigated as potential biomarkers for individuals affected by DTD. Chondroitin sulfate disaccharide analysis was performed on GAGs isolated from urine by HPLC after GAG digestion with chondroitinase ABC and ACII, while CXM was assessed in dried blood spots. Results from DTD patients were compared with an age-matched control population. Undersulfation of urinary GAGs was observed in DTD patients with some relationship to the clinical severity and underlying SLC26A2 variants. Lower than normal CXM levels were observed in most patients, even if the marker did not show a clear pattern in our small patient cohort because CXM values are highly dependent on age, gender and growth velocity. In summary, both non-invasive biomarkers are promising assays targeting various aspects of the disorder including overall metabolism of sulfated GAGs and endochondral ossification.
Topics: Animals; Anion Transport Proteins; Sulfate Transporters; Achondroplasia; Glycosaminoglycans; Biomarkers; Collagen; Sulfates
PubMed: 37454964
DOI: 10.1016/j.bone.2023.116838 -
Healthcare (Basel, Switzerland) May 2024Only a few studies, mainly qualitative thematic analyses of interviews, have dealt with the psychological experience of parents of children and adolescents with...
Only a few studies, mainly qualitative thematic analyses of interviews, have dealt with the psychological experience of parents of children and adolescents with osteogenesis imperfecta (OI), a rare genetic syndrome involving skeletal fragility and increased exposure to bone fractures. The aim of the present study was to evaluate both negative (i.e., parental burden and parenting stress) and positive (i.e., coping strategies and perceived social support) experiences of parents related to their children's disease and behaviour. The participants were 34 parents of children and adolescents with OI who completed a specifically developed online survey assessing their psychological experience with caregiving, their perception of the severity level of their children's condition and any possible behavioural problems experienced by their children. Data analyses showed that 65% of the parents showed a clinical level of caregiver burden and nearly 30% a clinical level of parenting stress. Caregiver burden was related to the perceived severity level of the condition and the externalising problems shown by their children. Concerning the positive aspects of the parents' experience, a high level of perceived social support was connected to a lower level of parenting stress; the same did not happen for caregiver burden. Coping strategies were connected to stress and burden; in particular, a higher level of stress corresponded to a higher level of avoidance, and a higher level of burden corresponded to a higher level of positive attitude.
PubMed: 38786428
DOI: 10.3390/healthcare12101018 -
Journal of Endocrinological... Feb 2024Osteoporosis is a metabolic bone disorder which increases fragility fracture risk. Elderly individuals, especially postmenopausal women, are particularly susceptible to... (Review)
Review
Osteoporosis is a metabolic bone disorder which increases fragility fracture risk. Elderly individuals, especially postmenopausal women, are particularly susceptible to osteoporosis. Although rare, osteoporosis in children and young adults is becoming increasingly evident, highlighting the need for timely diagnosis, management and follow-up. Early-onset osteoporosis is defined as the presence of a low BMD (Z-score of ≤ -2.0 in individuals aged < 20 years; T-score of ≤ -2.5 in those aged between 20 to 50 years) accompanied by a clinically significant fracture history, or the presence of low-energy vertebral compression fractures even in the absence of osteoporosis. Affected children and young adults should undergo a thorough diagnostic workup, including collection of clinical history, radiography, biochemical investigation and possibly bone biopsy. Once secondary factors and comorbidities are excluded, genetic testing should be considered to determine the possibility of an underlying monogenic cause. Defects in genes related to type I collagen biosynthesis are the commonest contributors of primary osteoporosis, followed by loss-of-function variants in genes encoding key regulatory proteins of canonical WNT signalling (specifically LRP5 and WNT1), the actin-binding plastin-3 protein (encoded by PLS3) resulting in X-linked osteoporosis, and the more recent sphingomyelin synthase 2 (encoded by SGMS2) which is critical for signal transduction affecting sphingomyelin metabolism. Despite these discoveries, genetic causes and underlying mechanisms in early-onset osteoporosis remain largely unknown, and if no causal gene is identified, early-onset osteoporosis is deemed idiopathic. This calls for further research to unravel the molecular mechanisms driving early-onset osteoporosis that consequently will aid in patient management and individualised targeted therapy.
Topics: Child; Aged; Humans; Female; Young Adult; Adult; Middle Aged; Fractures, Compression; Bone Density; Spinal Fractures; Osteoporosis; Wnt Signaling Pathway
PubMed: 37668887
DOI: 10.1007/s40618-023-02179-0 -
Brazilian Journal of Otorhinolaryngology 2023To screen the COL1A1 and COL1A2 gene mutation sites in a family with type I osteogenesis imperfecta (OI)/hearing loss and analyze the characteristics and recovery of...
OBJECTIVES
To screen the COL1A1 and COL1A2 gene mutation sites in a family with type I osteogenesis imperfecta (OI)/hearing loss and analyze the characteristics and recovery of hearing loss in patients with osteogenesis imperfecta.
METHODS
The basic clinical data of OI proband and her parents were collected, and the COL1A1 and COL1A2 genes were detected in peripheral blood by PCR amplification and generation Sanger sequencing. Literature of stapedial surgery in patients with osteogenesis imperfecta was collected.
RESULTS
The heterozygous mutation of the 26 exon c.1922_1923 ins C in the OI progenitor COL1A1 gene led to the amino acid frameshift mutation of p.Pro 601FS, which was not detected in the phenotypic parents. The homozygous of exon 28 c.1782>G in COL1A2 was detected in the proband and her parents, resulting in changes in the protein p.Pro 549Ala.
CONCLUSION
The clinical symptoms of the OI proband is caused by heterozygous mutation of the 26 exon c.1922_1923 ins C in COL1A1 gene. Stapedial surgery can provide short-term and long-term hearing benefits for OI patients with hearing loss.
LEVEL OF EVIDENCE
Level 4.
Topics: Female; Humans; Collagen Type I, alpha 1 Chain; Deafness; Hearing Loss; Mutation; Osteogenesis Imperfecta
PubMed: 37678008
DOI: 10.1016/j.bjorl.2023.101312 -
Journal of Bone and Mineral Research :... Aug 2023DNA sequencing is a reliable tool for identifying genetic variants in osteogenesis imperfecta (OI) but cannot always establish pathogenicity, particularly in variants...
DNA sequencing is a reliable tool for identifying genetic variants in osteogenesis imperfecta (OI) but cannot always establish pathogenicity, particularly in variants altering splicing. RNA sequencing can provide functional evidence of the effect of a variant on the transcript but requires cells expressing the relevant genes. Here, we used urine-derived cells (UDC) to characterize genetic variants in patients with suspected or confirmed OI and provide evidence on the pathogenicity of variants of uncertain significance (VUS). Urine samples were obtained from 45 children and adolescents; UDC culture was successful in 40 of these participants (age range 4-20 years, 21 females), including 18 participants with OI or suspected OI who had a candidate variant or VUS on DNA sequencing. RNA was extracted from UDC and sequenced on an Illumina NextSeq550 device. Principal component analysis showed that the gene expression profiles of UDC and fibroblasts (based on Genotype Tissue Expression [GTEx] Consortium data) clustered close together and had less variability than those of whole blood cells. Transcript abundance was sufficient for analysis by RNA sequencing (defined as a median gene expression level of ≥10 transcripts per million) for 25 of the 32 bone fragility genes (78%) that were included in our diagnostic DNA sequencing panel. These results were similar to GTEx data for fibroblasts. Abnormal splicing was identified in 7 of the 8 participants with pathogenic or likely pathogenic variants in the splice region or deeper within the intron. Abnormal splicing was also observed in 2 VUS (COL1A1 c.2829+5G>A and COL1A2 c.693+6T>G), but no splice abnormality was observed in 3 other VUS. Abnormal deletions and duplications could also be observed in UDC transcripts. In conclusion, UDC are suitable for RNA transcript analysis in patients with suspected OI and can provide functional evidence for pathogenicity, in particular of variants affecting splicing. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
Topics: Child; Female; Adolescent; Humans; Child, Preschool; Young Adult; Adult; Osteogenesis Imperfecta; Collagen Type I, alpha 1 Chain; Mutation; Collagen Type I; Sequence Analysis, RNA
PubMed: 37293821
DOI: 10.1002/jbmr.4865 -
The Pan African Medical Journal 2023
Topics: Humans; Osteogenesis Imperfecta
PubMed: 38035154
DOI: 10.11604/pamj.2023.46.14.40948 -
Biomedicine & Pharmacotherapy =... Jun 2024Qualitative alterations in type I collagen due to pathogenic variants in the COL1A1 or COL1A2 genes, result in moderate and severe Osteogenesis Imperfecta (OI), a rare...
Qualitative alterations in type I collagen due to pathogenic variants in the COL1A1 or COL1A2 genes, result in moderate and severe Osteogenesis Imperfecta (OI), a rare disease characterized by bone fragility. The TGF-β signaling pathway is overactive in OI patients and certain OI mouse models, and inhibition of TGF-β through anti-TGF-β monoclonal antibody therapy in phase I clinical trials in OI adults is rendering encouraging results. However, the impact of TGF-β inhibition on osteogenic differentiation of mesenchymal stem cells from OI patients (OI-MSCs) is unknown. The following study demonstrates that pediatric skeletal OI-MSCs have imbalanced osteogenesis favoring the osteogenic commitment. Galunisertib, a small molecule inhibitor (SMI) that targets the TGF-β receptor I (TβRI), favored the final osteogenic maturation of OI-MSCs. Mechanistically, galunisertib downregulated type I collagen expression in OI-MSCs, with greater impact on mutant type I collagen, and concomitantly, modulated the expression of unfolded protein response (UPR) and autophagy markers. In vivo, galunisertib improved trabecular bone parameters only in female oim/oim mice. These results further suggest that type I collagen is a tunable target within the bone ECM that deserves investigation and that the SMI, galunisertib, is a promising new candidate for the anti-TGF-β targeting for the treatment of OI.
Topics: Osteogenesis Imperfecta; Osteogenesis; Animals; Humans; Mesenchymal Stem Cells; Down-Regulation; Collagen Type I; Female; Quinolines; Mice; Child; Pyrazoles; Male; Cell Differentiation; Mutation; Disease Models, Animal; Receptor, Transforming Growth Factor-beta Type I; Child, Preschool; Cells, Cultured; Transforming Growth Factor beta; Unfolded Protein Response; Signal Transduction
PubMed: 38744219
DOI: 10.1016/j.biopha.2024.116725 -
Current Issues in Molecular Biology Apr 2024Osteogenesis imperfecta (OI) is a group of inherited disorders of connective tissue that cause significant deformities and fragility in bones. Most cases of OI are...
Osteogenesis imperfecta (OI) is a group of inherited disorders of connective tissue that cause significant deformities and fragility in bones. Most cases of OI are associated with pathogenic variants in collagen type I genes and are characterized by pronounced polymorphisms in clinical manifestations and the absence of clear phenotype-genotype correlation. The objective of this study was to conduct a comprehensive molecular-genetic and clinical analysis to verify the diagnosis of OI in six Russian patients with genetic variants in the and genes. Clinical and laboratory data were obtained from six OI patients who were observed at the Medical Genetics Center in Saint Petersburg from 2016 to 2023. Next-generation sequencing on MGISEQ G400 (MGI, China) was used for DNA analysis. The GATK bioinformatic software (version 4.5.0.0) was used for variant calling and hard filtering. Genetic variants were verified by the direct automatic sequencing of PCR products using the ABI 3500X sequencer. We identified six genetic variants, as follows pathogenic c.3505G>A (p. Gly1169Ser), c.769G>A (p.Gly257Arg), VUS c.4123G>A (p.Ala1375Thr), and c.4114A>T (p.Asn1372Tyr) in ; and likely pathogenic c.2035G>A (p.Gly679Ser) and c.739-2A>T in . In addition, clinical cases are presented due to the presence of the c.4114A>T variant in the gene. Molecular genetics is essential for determining different OI types due to the high similarity across various types of the disease and the failure of unambiguous diagnosis based on clinical manifestations alone. Considering the variable approaches to OI classification, an integrated strategy is required for optimal patient management.
PubMed: 38785520
DOI: 10.3390/cimb46050252 -
The Journal of Clinical Endocrinology... Jun 2024Deficiency of cartilage-associated protein (CRTAP) can cause extremely rare autosomal recessive osteogenesis imperfecta (OI) type VII. We investigated the pathogenic...
OBJECTIVE
Deficiency of cartilage-associated protein (CRTAP) can cause extremely rare autosomal recessive osteogenesis imperfecta (OI) type VII. We investigated the pathogenic mechanisms of CRTAP variants through functional studies on bones of patients with OI.
METHODS
Two nonconsanguineous families with CRTAP mutations were included and their phenotypes and genotypes were evaluated. Bone specimens were obtained from 1 patient with OI and a normal control during orthopedic surgery. The impacts of the novel variant on the CRTAP transcript were confirmed. The expression levels of CRTAP mRNA and CRTAP protein were analyzed. The quantification of prolyl 3-hydroxylation in the α1 chain of type I collagen was evaluated.
RESULTS
Patients with OI type VII had early-onset recurrent fractures, severe osteoporosis, and bone deformities. The c.621 + 1G > A and c.1153-3C > G mutations were identified in CRTAP in the patients with OI. The c.621 + 1G > A variant was a novel mutation that could impair mRNA transcription, leading to a truncated CRTAP protein. In a patient with c.621 + 1G > A and c.1153-3C > G mutations in CRTAP, the mRNA and protein levels of CRTAP in osteoblasts were significantly decreased and the osteoid volume and osteoblast numbers were markedly reduced compared with those in the normal control individual. This was simultaneously accompanied by significantly reduced prolyl 3-hydroxylation at Pro986 in the α1 chain of type I collagen and invisible active bone formation in bone.
CONCLUSION
The novel c.621 + 1G > A mutation in CRTAP expands the genotypic spectrum of type VII OI. Biallelic mutations of c.621 + 1G > A and c.1153-3C > G in CRTAP can lead to reduced CRTAP mRNA and deficient CRTAP protein in osteoblasts, which reduces 3-hydroxylation in Pro986 of the α1 chain of type I collagen and impairs bone formation, thus contributing to severe OI type VII.
Topics: Humans; Osteogenesis Imperfecta; Extracellular Matrix Proteins; Male; Female; Phenotype; Molecular Chaperones; Mutation; Child; Pedigree; Child, Preschool; Collagen Type I; Genotype; Osteoblasts; Collagen Type I, alpha 1 Chain; Adult; Adolescent
PubMed: 38214665
DOI: 10.1210/clinem/dgae025