Bone Marrow–Derived Cells Contribute to Vascular Inflammation but Do Not Differentiate Into Smooth Muscle Cell Lineages

Background— It has been proposed that bone marrow–derived cells infiltrate the neointima, where they differentiate into smooth muscle (SM) cells; however, technical limitations have hindered clear identification of the lineages of bone marrow–derived “SM cell–like” cells. Methods and Results— Using a specific antibody against the definitive SM cell lineage marker SM myosin heavy chain (SM-MHC) and mouse lines in which reporter genes were driven by regulatory programs for either SM-MHC or SM &agr;-actin, we demonstrated that although some bone marrow–derived cells express SM &agr;-actin in the wire injury–induced neointima, those cells did not express SM-MHC, even 30 weeks after injury. Likewise, no SM-MHC+ bone marrow–derived cells were found in vascular lesions in apolipoprotein E−/−mice or in a heart transplantation vasculopathy model. Instead, the majority of bone marrow–derived SM &agr;-actin+ cells were also CD115+CD11b+F4/80+Ly-6C+, which is the surface phenotype of inflammatory monocytes. Moreover, adoptively transferred CD11b+Ly-6C+ bone marrow cells expressed SM &agr;-actin in the injured artery. Expression of inflammation-related genes was significantly higher in neointimal subregions rich in bone marrow–derived SM &agr;-actin+ cells than in other regions. Conclusions— It appears that bone marrow–derived SM &agr;-actin+ cells are of monocyte/macrophage lineage and are involved in vascular remodeling. It is very unlikely that these cells acquire the definitive SM cell lineage.

[1]  K. Fujiu,et al.  Synthetic Retinoid Am80 Suppresses Smooth Muscle Phenotypic Modulation and In-Stent Neointima Formation by Inhibiting KLF5 , 2005, Circulation research.

[2]  R. Virmani,et al.  The good smooth muscle cells in atherosclerosis , 2000, Current atherosclerosis reports.

[3]  Tomoko Nakanishi,et al.  ‘Green mice’ as a source of ubiquitous green cells , 1997, FEBS letters.

[4]  H. Perlman,et al.  Bax‐mediated cell death by the Gax homeoprotein requires mitogen activation but is independent of cell cycle activity , 1998, The EMBO journal.

[5]  R. Nagai,et al.  Regulation of smooth muscle phenotype , 2003, Current atherosclerosis reports.

[6]  M. Bader,et al.  Smooth-muscle contraction without smooth-muscle myosin , 2000, Nature Cell Biology.

[7]  M. Makuuchi,et al.  A mouse model of vascular injury that induces rapid onset of medial cell apoptosis followed by reproducible neointimal hyperplasia. , 2000, Journal of molecular and cellular cardiology.

[8]  B. Herring,et al.  GATA-6 Can Act as a Positive or Negative Regulator of Smooth Muscle-specific Gene Expression* , 2005, Journal of Biological Chemistry.

[9]  M. Peach,et al.  Angiotensin II Induces Hypertrophy, not Hyperplasia, of Cultured Rat Aortic Smooth Muscle Cells , 1988, Circulation research.

[10]  R. Nagai,et al.  Characterization of a mammalian smooth muscle myosin heavy chain cDNA clone and its expression in various smooth muscle types. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[11]  R. Nagai,et al.  Diverse Contribution of Bone Marrow Cells to Neointimal Hyperplasia After Mechanical Vascular Injuries , 2003, Circulation research.

[12]  L. Kricka,et al.  Improved chemiluminescent western blotting procedure. , 1992, BioTechniques.

[13]  Michael S. Becker,et al.  Fate tracing reveals the endothelial origin of hematopoietic stem cells. , 2008, Cell stem cell.

[14]  Kakunaga Takeo,et al.  Transcriptional regulatory elements in the 5′ upstream and first intron regions of the human smooth muscle (aortic type) α-actin-encoding gene , 1991 .

[15]  G. Owens,et al.  Origin of neointimal smooth muscle: we've come full circle. , 2006, Arteriosclerosis, thrombosis, and vascular biology.

[16]  F. Geissmann,et al.  Blood monocytes: development, heterogeneity, and relationship with dendritic cells. , 2009, Annual review of immunology.

[17]  E. Petricoin,et al.  Laser Capture Microdissection , 1996, Science.

[18]  H. Nishimatsu,et al.  Endothelial nitric oxide synthase is essential for the HMG‐CoA reductase inhibitor cerivastatin to promote collateral growth in response to ischemia , 2001, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[19]  O. McDonald,et al.  Programming smooth muscle plasticity with chromatin dynamics. , 2007, Circulation research.

[20]  G. Owens,et al.  Development of a Smooth Muscle–Targeted Cre Recombinase Mouse Reveals Novel Insights Regarding Smooth Muscle Myosin Heavy Chain Promoter Regulation , 2000, Circulation research.

[21]  M. Makuuchi,et al.  Hematopoietic stem cells differentiate into vascular cells that participate in the pathogenesis of atherosclerosis , 2002, Nature Medicine.

[22]  M. Deschaseaux,et al.  Vascular smooth muscle differentiation of murine stroma: a sequential model. , 1999, Experimental hematology.

[23]  G. Owens,et al.  Molecular regulation of vascular smooth muscle cell differentiation in development and disease. , 2004, Physiological reviews.

[24]  A. Bellini,et al.  The role of the fibrocyte, a bone marrow-derived mesenchymal progenitor, in reactive and reparative fibroses , 2007, Laboratory Investigation.

[25]  Mark L. Benson,et al.  Isolation of vascular smooth muscle cells from a single murine aorta. , 2001, Methods in cell science : an official journal of the Society for In Vitro Biology.

[26]  M. Bennett,et al.  Progenitor cell-derived smooth muscle cells in vascular disease. , 2010, Biochemical pharmacology.

[27]  R. Nagai,et al.  Absence of p53 Leads to Accelerated Neointimal Hyperplasia After Vascular Injury , 2003, Arteriosclerosis, thrombosis, and vascular biology.

[28]  Franz Hofmann,et al.  SM22&agr; Modulates Vascular Smooth Muscle Cell Phenotype During Atherogenesis , 2004 .

[29]  J. Wilcox,et al.  Sequential patterns of chemokine- and chemokine receptor-synthesis following vessel wall injury in porcine coronary arteries. , 2007, Atherosclerosis.

[30]  L. Ashworth,et al.  Expression of human smooth muscle calponin in transgenic mice revealed with a bacterial artificial chromosome. , 2002, American journal of physiology. Heart and circulatory physiology.

[31]  H. Miller,et al.  Transfer of Endothelial Progenitor and Bone Marrow Cells Influences Atherosclerotic Plaque Size and Composition in Apolipoprotein E Knockout Mice , 2005, Arteriosclerosis, thrombosis, and vascular biology.

[32]  Markus G. Manz,et al.  Development of Monocytes, Macrophages, and Dendritic Cells , 2010, Science.

[33]  S. Sasayama,et al.  Transcriptional regulatory elements in the 5' upstream and first intron regions of the human smooth muscle (aortic type) alpha-actin-encoding gene. , 1991, Gene.

[34]  N. Caplice,et al.  Smooth Muscle Progenitor Cells in Human Blood , 2002, Circulation.

[35]  G. Owens,et al.  CArG elements control smooth muscle subtype-specific expression of smooth muscle myosin in vivo. , 2001, The Journal of clinical investigation.

[36]  Franz Hofmann,et al.  SM22alpha modulates vascular smooth muscle cell phenotype during atherogenesis. , 2004, Circulation research.