Phenotype analysis. A. The amino acid sequence of GMME1. B. GMME1 Mechanism of Action. GMME1 is capable of blocking CCR2 homodimerization and recruitment of β-arrestin. As a result, various biochemical responses take place such as an increase in p38 phosphorylation while p44/42, AKT, STAT3 are inhibited. In addition, a strong Ca2+ influx s triggered leading to the activation of caspase 3 and apoptosis. C. The phenotype of expanded C57BL/6 MSCs was analyzed by flow cytometry for various cell surface markers. D. An RT-PCR analysis demonstrates that MSC do not express CCR2. E. MSC culture under adipogenic or osteogenic conditions leads to their differentiation. Photographs were taken under light microscopy using a Contax167MT camera (Kyocera) with a 400 ISO film attached to an Axiovert25 Zeiss microscope (Carl Zeiss) F. Following the retroviral transduction of MSC, the GFP expression levels was monitored by flow cytometry with GMME1 secretion level at 33 ng/106 cell/24 hrs as detected by ELISA (P < 0.05; n = 3/group).