Haoyang Wang1, Cong Wang1, Limin Wang1, Tiantian Liu1, Zhiqiang Wang1, Hongjie You1, Yuanyuan Zheng1, Dali Luo2. 1. Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, PR China. 2. Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, PR China. Electronic address: luodl@ccmu.edu.cn.
Abstract
BACKGROUND/AIMS: It has been suggested that diabetes is associated with immune dysfunction, in which Ca2+ signaling malfunction in lymphocyte may contributes most. However, the pattern of the Ca2+ signal disorder and the mechanism(s) that explains the change are unclear. Here, in this study we aimed to investigate possible changes and mechanism(s) accounting for the internal Ca2+ signals in diabetic T lymphocyte upon stimulation. METHODS AND RESULTS: Using Fura-2-AM, we found a significant decrease in Ca2+ influx induced by thapsigargin (TG) and anti-CD3 antibody (OKT3) in T lymphocytes from blood of both diabetes patients and animals. Furthermore, a downregulated Orai1 protein expression, but not mRNA, was also observed in these cells using western blot and qRT-PCR, respectively. In addition, in high-glucose and agonist treated Jurkat T cells, Ca2+ entry and the release of interleukin-2 (IL-2) were also decreased. Orai1 expression reduced, while stromal interaction molecule 1 (STIM1) and other downstream proteins remained unchanged. CONCLUSION: This study demonstrates that the declined Orai1 expression, at least partly, contributes to the downregulated Ca2+ entry during lymphocyte excitation, providing an important mechanism for T lymphocyte malfunction in diabetes.
BACKGROUND/AIMS: It has been suggested that diabetes is associated with immune dysfunction, in which Ca2+ signaling malfunction in lymphocyte may contributes most. However, the pattern of the Ca2+ signal disorder and the mechanism(s) that explains the change are unclear. Here, in this study we aimed to investigate possible changes and mechanism(s) accounting for the internal Ca2+ signals in diabetic T lymphocyte upon stimulation. METHODS AND RESULTS: Using Fura-2-AM, we found a significant decrease in Ca2+ influx induced by thapsigargin (TG) and anti-CD3 antibody (OKT3) in T lymphocytes from blood of both diabetespatients and animals. Furthermore, a downregulated Orai1 protein expression, but not mRNA, was also observed in these cells using western blot and qRT-PCR, respectively. In addition, in high-glucose and agonist treated Jurkat T cells, Ca2+ entry and the release of interleukin-2 (IL-2) were also decreased. Orai1 expression reduced, while stromal interaction molecule 1 (STIM1) and other downstream proteins remained unchanged. CONCLUSION: This study demonstrates that the declined Orai1 expression, at least partly, contributes to the downregulated Ca2+ entry during lymphocyte excitation, providing an important mechanism for T lymphocyte malfunction in diabetes.