Deficiency of the stroke relevant HDAC9 gene attenuates atherosclerosis in accord with allele-specific effects at 7p21.1.
OBJECTIVE
Recent genome-wide association studies identified the histone deacetylase 9 (HDAC9) gene region as a major risk locus for large-vessel stroke and coronary artery disease. However, the mechanisms linking variants at this locus to vascular risk are poorly understood. In this study, we investigated the candidacy and directionality of HDAC9 in atherosclerosis and analyzed associations between risk alleles at 7p21.1 and plaque characteristics.


METHODS
Allele-dependent expression of HDAC9 was analyzed in human peripheral blood mononuclear cells of healthy donors. Effects of HDAC9 deficiency on atherosclerotic plaques were investigated in 18- and 28-week-old ApoE(-/-) mice by histology and immunohistochemistry. We further performed detailed plaque phenotyping and genotyping of rs2107595, the lead single-nucleotide polymorphism for large-vessel stroke, in carotid endarterectomy samples of 1858 subjects from the Athero-Express study.


RESULTS
Gene expression studies in peripheral blood mononuclear cells revealed increased mRNA levels of HDAC9 but not of neighboring genes (TWIST1/FERD3L) in risk allele carriers of rs2107595. Compared with HDAC9(+/+)ApoE(-/-) mice, HDAC9(-/-)ApoE(-/-) mice exhibited markedly reduced lesion sizes throughout atherosclerotic aortas and significantly less advanced lesions. The proportion of Mac3-positive macrophages was higher in plaques from HDAC9(-/-)ApoE(-/-) mice, but this was largely because of a lower proportion of advanced lesions. Analysis of human atherosclerotic plaques revealed no association between rs2107595 and specific plaque characteristics.


CONCLUSIONS
Our results suggest that HDAC9 represents the disease-relevant gene at the stroke and coronary artery disease risk locus on 7p21.1, and that risk alleles in this region mediate their effects through increased HDAC9 expression. Targeted inhibition of HDAC9 might be a viable strategy to prevent atherosclerosis.
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Sepiede
S
Azghandi
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Caroline
C
Prell
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Sander W
SW
van der Laan
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Manuela
M
Schneider
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Rainer
R
Malik
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Kerstin
K
Berer
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Norbert
N
Gerdes
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Gerard
G
Pasterkamp
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Christian
C
Weber
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.).
Christof
C
Haffner
From the Institute for Stroke and Dementia Research, Klinikum der Universität München, Munich, Germany (S.A., C.P., M.S., R.M., C.H., M.D.); Divisions Heart and Lungs and Laboratories and Pharmacy, University Medical Center Utrecht, Utrecht, The Netherlands (S.W.v.d.L., G.P.); Department of Neuroimmunology, Max Planck Institute of Neurobiology, Martinsried, Germany (K.B.); Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany (N.G., C.W.); and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany (M.D.). martin.dichgans@med.uni-muenchen.de.
Martin
M
Dichgans
D000368:Aged; D000483:Alleles; D000818:Animals; D001057:Apolipoproteins E / Q000235:genetics; D002340:Carotid Artery Diseases / Q000235:genetics* / Q000378:metabolism; D016894:Endarterectomy, Carotid; D005260:Female; D020869:Gene Expression Profiling; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006655:Histone Deacetylases / Q000235:genetics*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D012333:RNA, Messenger / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics*; D020521:Stroke / Q000235:genetics*
D001057:Apolipoproteins E; D012333:RNA, Messenger; D012097:Repressor Proteins; C486544:HDAC9 protein, human; C486545:Hdac9 protein, mouse; D006655:Histone Deacetylases
HDAC9 protein, human; atherosclerosis; stroke