Related Experiment Video
Updated: Oct 7, 2026

Peptides from Phage Display Library Modulate Gene Expression in Mesenchymal Cells and Potentiate Osteogenesis in Unicortical Bone Defects
Published on: December 10, 2010
Parathyroid hormone-related peptide stimulates osteogenic cell proliferation through protein kinase C activation of
1Calcium Research Laboratory, Department of Medicine, McGill University Health Centre and McGill University, Montreal, Quebec H3A 1A1, Canada.
Abstract:
We investigated the mechanisms of parathyroid hormone-related peptide (PTHrP)-mediated effects on osteogenic cells in primary rat bone marrow cell (BMC) cultures. We first demonstrated by reverse transcriptase-polymerase chain reaction and immunocytochemistry that BMCs express the type I parathyroid hormone/PTHrP receptor. Treatment with PTHrP increased osteogenic cell proliferation as determined by [(3)H]thymidine and bromodeoxyuridine incorporation and augmented osteogenic colonies. Immunocytochemistry and Western blotting revealed no direct effect on expression of the osteoblast markers, type I collagen, bone sialoprotein, and osteocalcin, indicating that PTHrP did not directly stimulate differentiation in this system. PTHrP increased mitogen-activated protein kinase (MAPK) activity in BMC and MAPK activity, and PTHrP-induced osteogenic cell proliferation could be blocked by the MEK inhibitor PD-098059. PTHrP also increased Ras activity in BMC. Although wortmannin and H8, inhibitors of phosphoinositol 3-kinase and protein kinase A, respectively, did not block PTHrP-stimulated Ras or MAPK activity, chelerythrin chloride, a known protein kinase C inhibitor, did block these PTHrP actions as well as PTHrP-induced osteogenic cell proliferation. These results demonstrate that PTHrP stimulates osteogenic cell proliferation in rat marrow mesenchymal progenitor cells through protein kinase C-dependent activation of the Ras and MAPK signaling pathway.
Related Concept Videos
Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
PI3K/mTOR/AKT Signaling Pathway
The Parathyroid Glands
Oxyphil cells, whose functions remain elusive, emerge during late puberty, adding a layer of complexity to the parathyroid gland's intricacies. In contrast, principal parathyroid cells undertake a vital role by producing...
MAPK Signaling Cascades
mTOR Signaling and Cancer Progression
The mTOR pathway or the...
mTOR Signaling and Cancer Progression
The mTOR pathway or the...
