The expression and significance of microtubule-associated protein 1 light chain 3-related protein-1 (LC3) mRNA in peripheral blood mononuclear cells in patients with systemic lupus erythematosus

Abstract

Increasing evidence supports the involvement of autophagy in the etiopathology of autoimmune diseases. Systemic lupus erythematosus (SLE) is a potentially fatal autoimmune disease characterized by production of multiple autoantibodies through poorly understood mechanism. In order to explore the role of autophagy in the development of SLE, the expression of autophagy related gene microtubule-associated protein 1 light chain 3 (MAPLC3) in peripheral blood mononuclear cells (PBMCs) was measured in patients with SLE. The mRNA levels of LC3 in PBMCs from 56 SLE patients and 45 healthy individuals were detected by real-time quantitative polymerase chain reaction (qPCR) technique. Autophagy in PBMCs was also determined by flow cytometry (FACs) in 20 SLE patients and 15 healthy controls. The correlation between LC3 mRNA expression and disease activity of SLE (SLEDAI) was then analyzed. The mRNA level of LC3 (RQ) in SLE patients was obviously downregulated compared with that in healthy population (1.30 ± 0.10 vs 1.35 ± 0.09; P = 0.029), paralleled with the decreased autophagy rate detected by flow cytometry in PBMCs of SLE patients [(2.21 ± 1.07) % vs (9.91 ± 4.01) %;P = 0.047]. Moreover, LC3 mRNA expression level was negatively correlated with SLEDAI (r = -0.337, P = 0.023). However, when the clinical features of 27 SLE patients with decreased LC3 mRNA expression (RQ<1.351) were compared with those of other 29 SLE patients with normal or high LC3 mRNA expression (RQ>1.351), increasing rates of arthritis, serositis, hematological abnormalities were noted in patients with decreased LC3 mRNA expression yet without statistically significance. However, there was a significant difference between two groups in the incidence of renal involvement (P = 0.028). The impaired autophagy due to downregulated LC3 mRNA level in SLE patients indicates that autophagy plays a role in mediating the occurrence and development of SLE.