OMICS Profiling Identifies Signatures of Senescence in Osteogenesis Imperfecta Osteoblasts Counteracted by 4-PBA

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Mutations in collagen I are the primary cause of osteogenesis imperfecta (OI), leading to abnormal collagen folding and impaired bone quality.
• Intracellular retention of misfolded collagen disrupts osteoblast homeostasis, contributing to OI pathology.
• 4-phenylbutyrate (4-PBA) is known to improve osteoblast function in OI models.

Purpose of the Study:

• To investigate the intracellular effects of mutant collagen retention in osteoblasts.
• To elucidate the mechanisms by which 4-PBA ameliorates osteoblast dysfunction in OI.
• To analyze the secretome and transcriptome of OI mouse models.

Main Methods:

• Utilized two dominant OI mouse models (Col1a1^+/G349C and Col1a2^+/G610C).
• Performed MS/MS proteomic analysis of conditioned media to identify secreted proteins.
• Conducted transcriptomic analysis to identify key genes and pathways involved.

Main Results:

• Secretome analysis revealed senescence-associated secretory phenotype (SASP) proteins and altered cytoskeletal/adhesion components.
• Transcriptomic analysis identified P53 as a central hub, indicating premature senescence.
• 4-PBA treatment reduced SASP proteins, modulated cytoskeletal/adhesion protein expression, and decreased senescent cell markers.

Conclusions:

• Cellular senescence is a key mechanism underlying osteoblast dysfunction in OI.
• 4-PBA effectively reduces cellular senescence and associated protein secretion in OI osteoblasts.
• 4-PBA demonstrates a novel therapeutic role in restoring osteoblast homeostasis in OI.