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Collagen XXIV Null Mouse Bones Are Not Osteoporotic Due to an Insufficiency of Osteoblastogenesis Factors
Author(s) -
Gordon Marion,
Lu Ziyao Eric,
Zhou Peihong,
Jeon Jae Yoon Louis,
Hahn Rita,
Gerecke Donald,
Ramirez Francesco,
Svoboda Kathy
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.699.1
Subject(s) - rankl , osteopontin , runx2 , endocrinology , medicine , bone remodeling , messenger rna , type i collagen , osteoporosis , collagen, type i, alpha 1 , osteopenia , osteocalcin , osteoblast , chemistry , biology , microbiology and biotechnology , gene expression , alkaline phosphatase , bone mineral , extracellular matrix , activator (genetics) , gene , receptor , biochemistry , enzyme , in vitro
Collagen XXIV is a non‐traditional member of the fibrillar collagens expressed in bone. The density of wild type (WT) and knock out (KO) mouse femurs was analyzed by micro CT. Femurs of 3 and 5 month old null mice were found to be osteoporotic as compared to those of WT mice. As a first avenue of investigation to understand this, the expression levels of mRNAs involved in the regulation of osteoblastogenesis were examined. cDNA was made from 7 days, 1 month, 2 months, 3 months, 6 months, 1 year and 1.5 year old femur RNA extracted from WT and KO mice. qPCR was used to evaluate the mRNA levels. GAPDH mRNA levels determined from the qPCR were used to normalize the results. Factors examined were RANK ligand (RANKL), Runx2, Lrp5, Indian Hedge Hog, FGF18, BMP4, Hey1 and Notch1. These mRNAs encoding osteoblastogenesis factors generally exhibited a greater expression level in the KO mice than in the WT mice. This was true for almost every time point. Since collagen XXIV null mice have osteoporotic bones, yet the bone cells express higher levels of osteoblastogenesis differentiation signals, we suggest the KO bones attempt to compensate for the cells' inability to make good mineralized bone. Future work will examine whether steps in bone remodeling is affected in KO mice. This work was supported by NEI EY009056, NIEHS ES005022 and NIAMSD AR055073