ABSTRACT
UNLABELLED: This study was initiated to investigate the efficacy of myocardial fibrosis intervention via signal transducer and activators of transcription (STAT) signaling using bone marrow (BM) mesenchymal stromal cells (MSC) in which being over-expressed with the aid of bispecific antibody (BiAb) and ultrasound-mediated microbubbles (MB). BiAb was prepared and combined with isolated MSC with CD47 overexpression from male mice and trans-fused into female mice with isoproterenol-induced myocardial fibrosis via the tail vein, followed by MB. This study included five groups. Five weeks after treatment, expression levels of the sex-determining region of Y-chromosome (SRY), matrix metalloproteinases (MMP)-9, tissue inhibitor of metalloproteinase (TIMP)-1 and vascular endothelial growth factor (VEGF) in myocardium were detected by fluorescent quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression of signal transducer and activators of transcription (STAT) 1 and STAT 3 was detected by Western blot. RESULTS: The highest homing number of MSC was in the CD47 + MSC + BiAb + MB group, second highest in the CD47 + MSC + BiAb group, and lowest in MSC alone. Compared with the Control group, CD47 + MSC + BiAb + MB, CD47 + MSC + BiAb, CD47 + MSC and MSC groups had decreased levels of MMP-9, TIMP-1, STAT 1 and collagen deposition, and increased levels of STAT 3. Up regulated STAT 3 and down regulated TIMP-1 were significantly different in CD47 + MSC + BiAb + MB compared with CD47 + MSC or CD47 + MSC + BiAb. CONCLUSION: CD47 can enhance the homing rate and repairing efficacy of MSC. MSC can improve MMP-TIMP expression in injured myocardium and interfere with myocardial fibrosis after homing, a mechanism that may be related to the STAT-mediated signaling pathway.
Subject(s)
CD47 Antigen/metabolism , Cardiomyopathies/prevention & control , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/metabolism , Myocardium/metabolism , STAT1 Transcription Factor/metabolism , STAT3 Transcription Factor/metabolism , Animals , Antibodies, Bispecific/immunology , CD47 Antigen/genetics , Cardiomyopathies/chemically induced , Cardiomyopathies/genetics , Cardiomyopathies/immunology , Cardiomyopathies/metabolism , Cardiomyopathies/pathology , Cells, Cultured , Collagen/metabolism , Disease Models, Animal , Female , Fibrosis , Gene Expression Regulation , Isoproterenol , Male , Matrix Metalloproteinase 9/genetics , Matrix Metalloproteinase 9/metabolism , Mesenchymal Stem Cells/immunology , Myocardium/immunology , Myocardium/pathology , Phenotype , Rats, Sprague-Dawley , Sex-Determining Region Y Protein/genetics , Sex-Determining Region Y Protein/metabolism , Signal Transduction , Tissue Inhibitor of Metalloproteinase-1/genetics , Tissue Inhibitor of Metalloproteinase-1/metabolism , Transfection , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolismABSTRACT
The primary function of white adipose tissues is to store excess energy. The current study aimed to investigate the roles of Gremlin 2 (Grem2), a glycoprotein in adipogenesis. Using polymerase chain reactionbased microarrays, it was determined that Grem2 was markedly downregulated in adipose tissues from obese animals and humans. In addition, 3T3L1 cells were used to investigate the details of the mechanisms underlying the antiadipogenic effects of Grem2. Grem2 expression was markedly decreased upon the induction of adipocyte differentiation, as demonstrated by reverse transcriptionquantitative polymerase chain reaction and western blot analysis. Notably, Grem2 overexpression inhibited adipogenesis, while knockdown of Grem2 led to an increase in adipogenesis. At the molecular level, Grem2 promotes nuclear translocation of ßcatenin, an integral Wnt signaling component. Consistently, inhibition of Wnt/ßcatenin signaling using a retrovirus targeting the ßcatenin coding region attenuated the antiadipogenic effects of Grem2. Therefore, to the best of our knowledge, the current study shows for the first time that Grem2 may be an important regulator of adipocyte differentiation.
