Exp Clin Endocrinol Diabetes 2009; 117(9): 480-485
DOI: 10.1055/s-0029-1202830
Article

© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

Possible Impact of Impaired Double-stranded RNA Degradation and Nitrosative Stress on Immuno-inflammatory Cascade in Type 2 Diabetes

G. M. Kocic 1 , R. Kocic 2 , R. Pavlovic 3 , T. Jevtovic-Stoimenov 1 , D. Sokolovic 1 , G. Nikolic 3 , V. Pavlovic 4 , S. Stojanovic 1 , J. Basic 1 , A. Veljkovic 1 , D. Pavlovic 1 , B. Kamenov 5
  • 1Department of Biochemistry, Medical Faculty, Nis, Serbia
  • 2Medical Faculty, Clinic for Endocrinology, Nis, Serbia
  • 3Department of Chemistry, Medical Faculty Nis, Nis, Serbia
  • 4Department of Physiology, Medical Faculty, Nis, Serbia
  • 5Clinic for Pediatrics, Medical Faculty, Nis, Serbia
Further Information

Publication History

received 02.01.2009 first decision 02.02.2009

accepted 02.02.2009

Publication Date:
08 April 2009 (online)

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Abstract

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-κB, 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-κB 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-κB activation, and possible MDA-5/IRF-3 axis downregulation, what may have an influence on further ineffective response against different pathogens.

References

Correspondence

Prof. G. M. KocicMD, MSc., PhD 

Department of Biochemistry Medical Faculty

Bul Dr Zorana Djindjica 81

18 000 Nis

Serbia

Email: kocicrg@yahoo.co.uk