Studies On The Expression Of The Recombinant Human High Mobility Group Box 1 (HMGB1) Protein In E.coli And Its Effects On The Biological Characteristics Of Human Bone Marrow Derived-mesenchymal Stem Cells (MSC)

HMGB1, which can enhance the proliferation, migration and differentiation of a variety of cells and induce cytoskeleton reorganization and wound healing, is considered as a new kind of chemokine and a signal of tissue damage. Mesenchymal stem cells (MSC) present themselves as the reservoirs for the repair and regeneration of various tissues. Different signals elicited by damage in the tissues can direct MSC to mobilize from the reservoirs, migrate into the damage sites, proliferate and differentiate into cells of connective tissue lineages. This led us to propose that HMGBl might mobilize MSC and affect its biological features. Therefore, in this study, the full-length of HMGBl cDNA was cloned, His-HMGBl fusion protein was purified, and the effect of HMGBl on the proliferation, migration, and differentiation towards ostogenesis, adipogenesis and chondrogenesis of MSC as well as the underlying mechansims were investigated in detail.Firstly, total cellular RNA was extracted from the peripheral mononuclear cells of normal adult, and the full length HMGB1 cDNA obtained by RT-PCR was cloned into expression vector pET-24a-d (+). Expression of the His-HMGBl fusion protein was induced by addition of IPTG. The bacterial lysate was subjected to affinity purification using HiTrap Chelating column. The biological activity was measured through its effect on the migration of rat smooth muscle cells (RSMC). The results showed that the recombinant HMGB1 protein was biologically active, in that it could induce the migration of RSMC as previously reported. Secondly, human bone...