347. Expression of the N-Formyl Peptide Receptor in Bone Marrow-Derived Human Mesenchymal Stem Cells
Authors: Anand Viswanathan, Richard G. Painter, Nicholas A. Lanson Jr, Guoshun Wang
Journal: Molecular Therapy (2006)

Human mesenchymal stem cells (hMSCs) from adult bone marrow can differentiate into a variety of different cell types including airway epithelial cells, suggesting the theraputic potential of stem cells in tissue injury repair. However, approaches for the efficient recruitmentof hMSCs to specific sites have not been established. To this end, we have investigated whether hMSCs express the N-formyl peptide receptor (FPR), which is typically expressed in polymorphonuclear leukocytes and is responsible for the neutrophil chemotactic response. Reverse transcription PCR using FPR specific primers resulted in a positive amplification of this mRNA. Sequencing of the amplicon proved 100% homology to the published FPR sequence. Immunofluorescence staining using a monoclonal antibody against human FPR and flow cytometric analyses demonstrated that hMSCs express FPR at the protein level. Actin polymerization after formylated peptide stimulation is one of the basic cellular responses indicative of the FPR function. We incubated hMSCs with 100nM of N-formyl methionyl leucyl phenylalanine (fMLP). Staining with phalloidin-conjugated fluorescein and flow cytometric analyses showed significant F-actin polymerization in hMSCs. Also, hMSCs were attracted toward fMLP gradients in Boyden chambers and binding of flourescein-labeled formyl-Nle-Leu-Phe-Nle-Tyr-Lys displayed the existence and functionality of the receptor in hMSCs. Thus, we conclude that hMSCs express functional formyl peptide receptors on their surface membrane and are capable of chemotaxis toward their ligand. The expression of the N-formyl peptide receptor on hMSCs, cells not normally associated with immune responses, could serve as a mechanism of directing stem cells to the sites of inflammation. Therefore, endogenous expression or over-expression of the receptor within hMSCs could be manipulated in a manner to target these cells to specific inflammatory sites, such as the lungs in cystic fibrosis.Funded in part by CFF and NIH. We thank Drs. Darwin J. Prockop and Bruce Bunnell at Tulane University for providing human hMSCs, technical support and advice. Human mesenchymal stem cells (hMSCs) from adult bone marrow can differentiate into a variety of different cell types including airway epithelial cells, suggesting the theraputic potential of stem cells in tissue injury repair. However, approaches for the efficient recruitmentof hMSCs to specific sites have not been established. To this end, we have investigated whether hMSCs express the N-formyl peptide receptor (FPR), which is typically expressed in polymorphonuclear leukocytes and is responsible for the neutrophil chemotactic response. Reverse transcription PCR using FPR specific primers resulted in a positive amplification of this mRNA. Sequencing of the amplicon proved 100% homology to the published FPR sequence. Immunofluorescence staining using a monoclonal antibody against human FPR and flow cytometric analyses demonstrated that hMSCs express FPR at the protein level. Actin polymerization after formylated peptide stimulation is one of the basic cellular responses indicative of the FPR function. We incubated hMSCs with 100nM of N-formyl methionyl leucyl phenylalanine (fMLP). Staining with phalloidin-conjugated fluorescein and flow cytometric analyses showed significant F-actin polymerization in hMSCs. Also, hMSCs were attracted toward fMLP gradients in Boyden chambers and binding of flourescein-labeled formyl-Nle-Leu-Phe-Nle-Tyr-Lys displayed the existence and functionality of the receptor in hMSCs. Thus, we conclude that hMSCs express functional formyl peptide receptors on their surface membrane and are capable of chemotaxis toward their ligand. The expression of the N-formyl peptide receptor on hMSCs, cells not normally associated with immune responses, could serve as a mechanism of directing stem cells to the sites of inflammation. Therefore, endogenous expression or over-expression of the receptor within hMSCs could be manipulated in a manner to target these cells to specific inflammatory sites, such as the lungs in cystic fibrosis. Funded in part by CFF and NIH. We thank Drs. Darwin J. Prockop and Bruce Bunnell at Tulane University for providing human hMSCs, technical support and advice.