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.
Mitochondrial Dysfunction in T Cells Precede Disease Development in Lupus-Prone Mice.
Telarico4, Tiffany, Fernandez4, David R., Hofbauer2, Ann F., Gilkeson1, Gary S., Oates3, Jim C., Perl5, Andras
T lymphocytes from patients with systemic lupus erythematosus (SLE) exhibit increased nitric oxide (NO) production, elevation of the mitochondrial transmembrane potential (DYm) or mitochondrial hyperpolarization (MHP), and ATP depletion which predispose to pro-inflammatory death via necrosis. T lymphocytes express the endothelial isoform of NO synthase (eNOS). Here, we examined whether mitochondrial dysfunction precedes the onset of disease in murine models of SLE.
Mitochondrial function, calcium flux, and the production of nitric oxide (NO) and underlying changes in gene expression were investigated in MRL/lpr, MRL/lpr/iNOS-/-, MRL/lpr/eNOS-/-, MRL, C57BL/6-lpr, C57BL/6, NZB × NZW F1, Balb-c/NZW, NZM2328, and NZM2328/R27 female mice that were matched for age and studied in parallel. DYm (DiOC6 and TMRM), mitochondrial mass (MTG and NAO), NO production (DAF-FM and DAR-4M), reactive oxygen species (DCF-DA), intracellular reduced glutathione (GSH by MCB fluorescence) and cytosolic ([Ca2+]c) and mitochondrial calcium ([Ca2+]m) were measured by flow cytometry. Expression of the voltage-dependent anion channel 1 (VDAC1) and transaldolase that regulate GSH and DYm was investigated in splenocytes and CD4+ T cells by western blotting. As disease development, glomerulonephritis was monitored by proteinuria and histopathology. P values < 0.05 calculated by GraphPad Prism version 5.0 using paired or unpaired two-tailed t-test were considered significant.
MHP, increased mitochondrial mass, [Ca2+]m and ROI production and reduced GSH were found in CD3+ T cells from disease-free MRL/lpr but not from MRL or from C57BL/6-lpr mice relative to C57BL/6 control mice at 3 months of age. Consistent with these changes, expression of the VDAC1 (up to 7 fold increase, p=0.0008) and transaldolase (67% increase, p=0.034), genes that influence DYm, were elevated in MRL/lpr splenocytes and CD4+ T cells. NO production, DYm and mitochondrial mass were all increased in 11-month-old (NZB × NZW) F1 mice after disease onset, but these parameters were not consistently elevated prior to disease development at 6 months of age. However, increased expression of VDAC1 was detected at 6 months of age and preceded the onset of SLE (3.5-fold increase; p=0.006). NO production (DAF-FM fluorescence), DYm (TMRM fluorescence), mitochondrial mass (NAO), [Ca2+]c and [Ca2+]m stores were reduced in CD3+ T cells from C57BL/6/eNOS-/- mice relative to C57BL/6 controls. NO production (DAF-FM fluorescence p=0.001) and mitochondrial and [Ca2+]c stores were reduced in CD3+ T cells from MRL/lpr eNOS-/- mice (Fluo-3 fluorescence; p=0.03) relative to MRL/lpr controls.
Mitochondrial dysfunction, characterized by MHP and increased [Ca2+]m as well as overexpression of VDAC1 and transaldolase, precede disease development in lupus-prone mice. Increased [Ca2+]m of MRL/lpr mice may be dependent on the expression of eNOS.
To cite this abstract, please use the following information:
Telarico, Tiffany, Fernandez, David R., Hofbauer, Ann F., Gilkeson, Gary S., Oates, Jim C., Perl, Andras; Mitochondrial Dysfunction in T Cells Precede Disease Development in Lupus-Prone Mice. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :437