Kocic G M, Kocic R, Pavlovic R, Jevtovic-Stoimenov T, Sokolovic D, Nikolic G, Pavlovic V, Stojanovic S, Basic J, Veljkovic A, Pavlovic D, Kamenov B
Department of Biochemistry, Bul Dr Zorana Djindjica 81, 18 000 Nis, Serbia.
Exp Clin Endocrinol Diabetes. 2009 Oct;117(9):480-5. doi: 10.1055/s-0029-1202830. Epub 2009 Apr 8.
The immune response can be triggered by molecules derived from microorganisms (PAMP) or from molecules derived from damaged or dead host cells, known as the damage-associated molecular-pattern molecules (DAMP). Their immune effects are accompanied by altered redox environment. The level of stable end products of nitric oxide (NO)- plasma nitrate and nitrite (NOx), carbonyl groups (PCO) and nitrotyrosine (NTY), in relation to the metabolism of dsRNAs (poly I:C and poly A:U) and xanthine oxidase (XO activity), in plasma of type2 diabetic patients was determined. Thirty-six patients with type 2 diabetes (age group 34-66 years, 19 male and 17 female) were allocated to the study. Diabetic patients had a significantly higher level of plasma NOx products, NTY and PCO, fructosamine (FA) and XO activity indicating about altered redox environment. The concentration of circulating ribonucleic acids (CNAs) was significantly higher in type 2 diabetic patients, which was accompanied by a significantly decreased activity of RNase against double stranded RNA forms (poly I:C and poly A:U), compared to control samples. To determine whether CNAs, as possible DAMP molecules, are capable of exerting effect on inflammatory and host antiviral response, the effect of isolated CNAs on NF-kappaB, Bcl-2, Bax, MDA-5 and IRF-3 regulation was evaluated in culture of fresh isolated thymocytes. Circulating nucleic acids isolated from type 2 diabetic patients were able to upregulate NF-kappaB more than control RNA samples. In the same experimental conditions the mild Bcl-2 upregulation, followed by the marked Bax upregulation, was demonstrated. Since the Bcl-2/Bax ratio was lower in type 2 diabetic samples, obtained results may implicate that CNAs may exert proapoptotic response in type 2 diabetes. The CNAs isolated from diabetic patients were able to downregulate MDA-5 and IRF-3, very important subjects of the surveillance and cellular anti-viral response. The major findings of the present study are that impaired dsRNA metabolism may lead to increased level of different sized RNAs in type 2 diabetic patients. Acting as possible DAMP molecules, they may contribute to higher susceptibility of immune cells to inflammatory cascade via NF-kappaB activation, and possible MDA-5/IRF-3 axis downregulation, what may have an influence on further ineffective response against different pathogens.
免疫反应可由微生物衍生的分子（病原体相关分子模式，PAMP）或受损或死亡宿主细胞衍生的分子触发，后者被称为损伤相关分子模式分子（DAMP）。它们的免疫效应伴随着氧化还原环境的改变。测定了2型糖尿病患者血浆中一氧化氮（NO）的稳定终产物——血浆硝酸盐和亚硝酸盐（NOx）、羰基（PCO）和硝基酪氨酸（NTY）的水平，以及与双链RNA（聚肌胞苷酸和聚腺苷酸:尿苷酸）代谢和黄嘌呤氧化酶（XO活性）相关的水平。36例2型糖尿病患者（年龄34 - 66岁，男性19例，女性17例）被纳入研究。糖尿病患者血浆NOx产物、NTY、PCO、果糖胺（FA）和XO活性水平显著升高，表明氧化还原环境发生了改变。与对照样本相比，2型糖尿病患者循环核糖核酸（CNA）的浓度显著更高，同时针对双链RNA形式（聚肌胞苷酸和聚腺苷酸:尿苷酸）的核糖核酸酶活性显著降低。为了确定作为可能的DAMP分子的CNA是否能够对炎症和宿主抗病毒反应产生影响，在新鲜分离的胸腺细胞培养物中评估了分离的CNA对核因子κB（NF-κB）、Bcl-2、Bax、黑色素瘤分化相关基因5（MDA-5）和干扰素调节因子3（IRF-3）调节的影响。从2型糖尿病患者分离的循环核酸比对照RNA样本更能上调NF-κB。在相同实验条件下，显示出Bcl-2轻度上调，随后Bax显著上调。由于2型糖尿病样本中Bcl-2/Bax比值较低，所得结果可能意味着CNA可能在2型糖尿病中发挥促凋亡反应。从糖尿病患者分离的CNA能够下调MDA-5和IRF-3，它们是监测和细胞抗病毒反应的非常重要的指标。本研究的主要发现是，2型糖尿病患者双链RNA代谢受损可能导致不同大小RNA水平升高。作为可能的DAMP分子，它们可能通过激活NF-κB以及可能下调MDA-5/IRF-3轴，导致免疫细胞对炎症级联反应的易感性增加，这可能会影响对不同病原体的进一步无效反应。
