Osteogenic potential of human calcitonin gene-related peptide alpha gene-modified bone marrow mesenchymal stem cells

Most of the basic and clinical studies of osteonecrosis of the femoral head (ONFH) are restricted to bone tissues only, whereas various systems are involved in the onset and development of ONFH, including nervous system. Peptidergic nerve participates in the neuronal regulation of bone metabolism and anabolism, and plays key roles in the growth, repair and reconstruction of bone. Calcitonin gene-related peptide (CGRP), which is secreted by peptidergic nerve, is the main mediator of bone metabolism. It dramatically promotes the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Additionally, it enhances the osteoblast mass and the rate of osteoblast formation, and reduces the bone resorption by acting on osteoblasts and osteoclasts. Hence, we aimed to construct recombinant retrovirus vector pLNCX(2)-hCGRPα and to investigate the proliferation and osteogenic potential of hCGRPα-producing BMSCs (BMSCs/pLNCX(2)-hCGRPα) after virus infection.

The constructed recombinant retrovirus vector pLNCX(2)-hCGRPα was transfected into PT67 packaging cells by lipofectamine 2000. Virus was collected for BMSCs infection. The mRNA and protein expression of hCGRPα was examined by reverse transcription polymerase chain reaction (RT-PCR) and Western blotting, respectively. The cell proliferation was determined by methyl thiazoleterazolium (MTT) assay. The osteogenic potential of BMSCs was evaluated by alkaline phosphatase (ALP) activity.

Both mRNA and protein expression of hCGRPα was detected in BMSCs/pLNCX(2)-hCGRPα cells. These cells exhibited significantly elevated proliferation and ALP value as compared with control BMSCs (P < 0.05).

BMSCs/pLNCX(2)-hCGRPα cells could stably express hCGRPα and showed promoted proliferation ability and osteogenic potential as compared with control BMSCs.