PUBLICATION

Membrane Palmitoylated Protein 7 is Required for Osteogenesis and is Linked with Bone Mineralization and Osteoporosis: The Functional Evaluation of GEFOS GWAS Hit

Authors
Malavašič, P., Lojk, J., Lovšin, M.N., Komadina, R., Haring, G., Trebše, R., Rivadeneira, F., Karasik, D., Ostanek, B., Marc, J.
ID
ZDB-PUB-251020-16
Date
2025
Source
Calcified tissue international   116: 128128 (Journal)
Registered Authors
Karasik, David
Keywords
MPP7, Adipogenesis, HOS cell lineage, Human bone tissue, Human muscle tissue
MeSH Terms
  • Animals
  • Bone Density/genetics
  • Calcification, Physiologic*/genetics
  • Calcification, Physiologic*/physiology
  • Cell Differentiation/physiology
  • Female
  • Genome-Wide Association Study
  • Guanylate Kinases*/genetics
  • Guanylate Kinases*/metabolism
  • Humans
  • Osteoblasts/metabolism
  • Osteogenesis*/genetics
  • Osteogenesis*/physiology
  • Osteoporosis*/genetics
  • Osteoporosis*/metabolism
  • Zebrafish
PubMed
41105261 Full text @ Calcif. Tissue Int.
Abstract
Genome-wide association studies have identified multiple loci associated with bone mineral density, a major determinant of osteoporotic fracture risk. At one such locus, genetic, bioinformatic, and zebrafish knockout data strongly prioritize membrane palmitoylated protein 7 (MPP7) as a candidate gene, although its precise role in bone biology remains poorly defined. MPP7 encodes a member of the p55 Stardust family of membrane-associated guanylate kinase proteins, which are key regulators of epithelial cell polarity and junctional organization. Here, we investigated the functional role of MPP7 in bone biology. We found that MPP7 expression was significantly reduced-by approximately twofold-in bone tissue from osteoporotic patients compared with osteoarthritic patients and non-osteoporotic controls. Furthermore, we generated a CRISPR/Cas9-mediated MPP7 knockout in the human osteosarcoma HOS cell line and demonstrated that MPP7 deletion impairs osteogenic differentiation and completely abrogates mineralization through downregulation of ALPL expression. Knockout cells also displayed altered morphology, suggesting that MPP7 influences osteoblast function via effects on cell polarity and adhesion. Collectively, our findings, together with zebrafish genetic evidence, indicate that MPP7 plays a critical role in osteoblast differentiation and mineralization and may contribute to osteoporosis susceptibility in humans.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping