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.
The HRES-1/RAB4 Lupus Susceptibility Gene Promotes Nitric Oxide Production in Human T Cells through Direct Interaction with Endothelial Nitric Oxide Synthase Interacting Protein.
Telarico1, Tiffany N., Doherty1, Edward H., Fernandez1, David R., Bartos1, Adam, Oess2, Stephanie, Muller-Esterl2, Werner, Perl3, Andras
Polymophic haplotypes of the HRES-1 endogenous retrovirus influence lupus susceptibility. One of its gene products, HRES-1/Rab4 is overexpressed in lupus T cells and contributes to altered T cell activation via regulating endosomal recycling of cell surface CD4 and transferrin receptors as well as the CD3 zeta chain that transmits signals from the immunological synapse (IS). Increased production of nitric oxide (NO) has been linked to abnormal activation of lupus T cells and NO production has been localized to the IS. Here we investigated the role of HRES-1/Rab4 in compartmentalized production of NO.
Expression of proteins involved in NO production was investigated by RNA microrray and western blot analysis of negatively isolated T cells from 44 Caucasian female lupus patients and 23 age-matched Caucasian female controls. NO production was measured by flow cytometry. The effect of HRES-1/Rab4 on NO production and expression of proteins involved in NO synthesis was investigated by overexpression of a wild-type HRES-1/Rab4 and its dominant-negative form HRES-1/Rab4S27N. Direct interaction of HRES-1/Rab4 with potential binding partners was assessed by pull-down assays.
NO production was increased in lupus T cells by 32% (p=0.009) Expression of endothelial NO synthase (eNOS) interacting protein (NOSIP) was reduced by 61% in lupus T cells (p=0.010). Over-expression of HRES-1/Rab4 suppressed NOSIP expression and shifted it to the cytosol, enhanced eNOS expression, and NO production while dominant-negative HRES-1/Rab4S27N had the opposite effects in human T cells. NOSIP was efficiently pulled down by HRES-1/Rab4-GST but not by GST alone in Jurkat cells and human peripheral blood lymphocytes.
The results indicate that over-expression of HRES-1/Rab4 promotes NO production through direct interaction with NOSIP and its targeting to the cytosol which may activate eNOS and modulate IS formation in human T cells.
To cite this abstract, please use the following information:
Telarico, Tiffany N., Doherty, Edward H., Fernandez, David R., Bartos, Adam, Oess, Stephanie, Muller-Esterl, Werner, et al; The HRES-1/RAB4 Lupus Susceptibility Gene Promotes Nitric Oxide Production in Human T Cells through Direct Interaction with Endothelial Nitric Oxide Synthase Interacting Protein. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :2275