Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Characterization of Single Histone Deacetylase Isoforms in Endothelial Cells Derived from Progenitors in Systemic Sclerosis.

Hemmatazad1,  Hossein, Maurer1,  Britta, Michel1,  Beat A., Gay1,  Renate E., Steffen1,  Gay, Avouac2,  Jèrome, Distler1,  Oliver

Center of Experimental Rheumatology, University Hospital and Zurich Center of Integrative Human Physiology (ZIHP), Zurich, Switzerland
Department of Rheumatology A, Cochin Hospital, Universitè Paris Descartes, INSERM U781, Paris, France

Background and Objectives:

Microvascular damage is a major concern in the pathogenesis of SSc with outcome depending on the extent and severity of vascular lesions. Considering reports which indicate a key role of specific histone deacetylase (HDAC) isoforms in angiogenesis, we investigate here the expression patterns of HDACs in endothelial cells derived from circulating progenitors (EPCs) from patients with SSc and from normal healthy controls, under basal and under hypoxic conditions.

Methods:

Late outgrowth EPC-derived cells were obtained from the peripheral blood of 11 patients with SSc and 6 healthy individuals according to the EUSTAR recommendations on endothelial precursor cells in SSc. All patients fulfilled the ACR classification criteria for SSc. Gene expression patterns of HDACs (1–11) and HoxA9, the key transcription factor for endothelial cells, were analyzed under basal conditions and under hypoxic (1% oxygen for 6h) conditions by TaqMan Real-time PCR using 18S for normalization. To assess the expression on protein level, antibodies against HDAC1 and HoxA9 were used for western blot.

Results:

Under basal conditions, the mRNA levels of HDAC1, 2 and 5 were significantly up regulated in endothelial cells from SSc patients by 4.33 ± 1.75, 7.40 ± 3.40 and 1.51 ± 0.54 (x-fold ± SD, p<0.05) respectively, as compared to normal healthy cells. Moreover, the expression of HDAC6 and HDAC10 were reduced by 44 ± 15 and 31 ± 20 (%± SD, p<0.05) in SSc vs. healthy EPCs. After 6h of hypoxia, we observed a notable increase in the expression of mRNA levels for HDAC1 and 2 by 2.47 ± 0.92 and 3.08 ± 1.27 (x-fold ± SD, p<0.05) in SSc cells as compared to healthy controls. In contrast, the expression levels of HDAC6 and 7 were down regulated by 31 ± 20 and 36 ± 19 (%± SD, p<0.05). It is known that HDAC1 activity is required for the expression of HoxA9 which regulates important genes in vascular formation. We observed a significant down regulation of HoxA9 mRNA by 95 ± 3 % in SSc endothelial cells vs. healthy cells. Using western blot we confirmed this data on protein level. Of interest, the protein expression of HDAC1 was in contrast to the mRNA level reduced in SSc (n=3) as compared to healthy controls under basal conditions. It has been reported that some microRNAs regulate Hox genes. Therefore, we hypothesize that microRNAs prevent the transcription of HDAC1 mRNA and regulate thereby the expression of HoxA9.

Conclusions:

We conclude that vasculopathy in SSc might be related to the different expression of HDACs in endothelial cells. Altered expression of HDACs could possibly regulate the expression of important genes involved in vascular formation via transcription factors like HoxA9 and contribute to altered angiogenesis in SSc.

To cite this abstract, please use the following information:
Hemmatazad, Hossein, Maurer, Britta, Michel, Beat A., Gay, Renate E., Steffen, Gay, Avouac, Jèrome, et al; Characterization of Single Histone Deacetylase Isoforms in Endothelial Cells Derived from Progenitors in Systemic Sclerosis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1988
DOI: 10.1002/art.29753

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