Leukocyte Mitochondrial DNA Alteration in Systemic Lupus Erythematosus and Its Relevance to the Susceptibility to Lupus Nephritis

Abstract

The role of mitochondrial DNA (mtDNA) alterations in the pathophysiology of systemic lupus erythematosus (SLE) remains unclear. We investigated sequence variations in the D310 region and copy number change of mtDNA in 85 SLE patients and 45 normal subjects. Leukocyte DNA and RNA were extracted from leukocytes of the peripheral venous blood. The D310 sequence variations and copy number of mtDNA, and mRNA expression levels of mtDNA-encoded genes in leukocytes were determined by quantitative real-time polymerase chain reaction (Q-PCR) and PCR-based direct sequencing, respectively. We found that leukocyte mtDNA in SLE patients exhibited higher frequency of D310 heteroplasmy (69.4% vs. 48.9%, p = 0.022) and more D310 variants (2.2 vs. 1.7, p = 0.014) than those found in controls. Among normal controls and patients with low, medium or high SLE disease activity index (SLEDAI), an ever-increasing frequency of D310 heteroplasmy was observed (p = 0.021). Leukocyte mtDNA copy number tended to be low in patients of high SLEDAI group (p = 0.068), especially in those harboring mtDNA with D310 heteroplasmy (p = 0.020). Moreover, the mtDNA copy number was positively correlated with the mRNA level of mtDNA-encoded ND1 (NADH dehydrogenase subunit 1) (p = 0.041) and ATPase 6 (ATP synthase subunit 6) (p = 0.030) genes. Patients with more D310 variants were more susceptible to lupus nephritis (p = 0.035). Taken together, our findings suggest that decrease in the mtDNA copy number and increase in D310 heteroplasmy of mtDNA are related to the development and progression of SLE, and that the patients harboring more D310 variants of mtDNA are more susceptible to lupus nephritis.

Mitochondrial DNA damage is associated with damage accrual and disease duration in patients with Systemic Lupus Erythematosus

“…Indeed, treatment with hydrogen peroxide results in a significant loss of mtDNA molecules and reduced mitochondrial function in an embryonic cell line 44 . In another study, although no significant differences were found in the numbers of mtDNA copies in lupus patients compared to healthy individuals, mtDNA copy numbers decreased among lupus patients with low SLEDAI scores relative to patients exhibiting medium and high scores 45 . Thus, our findings suggest that mtDNA damage in the form of oxidative lesions or mtDNA depletion may be contributing to SLE pathogenesis.…”

Mitochondrial DNA alterations correlate with the pathological status and the immunological ER, PR, HER-2/neu, p53 and Ki-67 expression in breast invasive ductal carcinoma

“…The D310 region of mtDNA was amplified by PCR and then subjected to direct sequencing as previously described (20,23,24). Each 50 µl PCR reaction contained 25 µl of RBC SensiZyme ® Hotstart Taq Premix (RBC Bioscience, New Taipei City, Taiwan), 22 µl of PCR-grade H 2 O, 1 µl of each primer (H76-1, 5'-CACGCGATA GCATTGCGA-3'; and L335, 5'-TAAGTGCTGTGGCCAGA AGC-3'), and 1 µl of sample DNA (10 ng/µl).…”

“…After confirmation by 3% agarose gel electrophoresis, the PCR products were subjected to direct sequencing (MB Mission Biotech, Taipei, Taiwan). The D310 sequence variations, including patterns of homoplasmy or heteroplasmy, number of detected D310 variants, and the predominant D310 variant were determined as previously described (20,23,24). Compared to the D310 sequences of the paired non-cancerous breast tissue, any sequence alterations detected in the BIDC were defined as D310 mutations (20).…”

Aberrant Free Radical Biology Is a Unifying Theme in the Etiology and Pathogenesis of Major Human Diseases

“…The vascular biology papers included reports regarding both cerebral vascular [4] and pulmonary vascular [3] endothelial cell function. Also included in this issue are papers describing the contributions of ROS and mitochondrial function to other more rare and specific disease states including lupus [8] and epilepsy [9] and chronic regional pain syndrome [10]. Popular topics in this special issue include mitochondrial function [1,2,5,8,11], oxidative stress [2,6,12–15], nitric oxide [3,16–18], cellular signaling [3,13,19].…”

“…Also included in this issue are papers describing the contributions of ROS and mitochondrial function to other more rare and specific disease states including lupus [8] and epilepsy [9] and chronic regional pain syndrome [10]. Popular topics in this special issue include mitochondrial function [1,2,5,8,11], oxidative stress [2,6,12–15], nitric oxide [3,16–18], cellular signaling [3,13,19]. In addition there are reports pertaining to endoplasmic reticulum stress [12], hypoxic stem cell niches [20], adaptive responses to oxidative stress [21], and a paper describing a Columbian medicinal plant that inhibits lipid peroxidation [22].…”