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AB0051 Monocytes from Patients with Rheumatoid Arthritis and Type 2 Diabetes Mellitus Display an Increased Production of IL-1β Via the NLRP3-Inflammasome Activation. A Possible Implication for Therapeutic Decision in These Patients
  1. P. Ruscitti,
  2. P. Di Benedetto,
  3. P. Cipriani,
  4. V. Liakouli,
  5. O. Berardicurti,
  6. F. Carubbi,
  7. S. Alvaro,
  8. R. Giacomelli
  1. Division of Rheumatology, Department of Biotechnological and Applied Clinical Science, School of Medicine, University of L'Aquila, Division of Rheumatology, Department of Biotechnological and Applied Clinical Science, School of Medicine, University of L'Aquila, L'Aquila, Italy

Abstract

Background A better understanding about the mechanisms involved in the pathogenesis of type 2 diabetes mellitus (T2DM) showed that inflammatory cytokines such as tumor TNF-α and IL-1β play a pivotal role, mirroring data largely reported in rheumatoid arthritis (RA) [1]. Both preclinical and clinical studies confirmed the usefulness of IL-1β antagonism therapy in both diseases [2]. IL-1β is mainly produced by monocytes/macrophages. Hyperglycaemia may be able to modulate, in the cytoplasm of these cells, the assembly of a cytosolic multiprotein platforms, composed by 3 molecules: NLRP3 sensor protein; ASC adaptor protein; caspase-1, the so called NLRP3-inflammasome, where, the inactive pro-IL-1β is cleaved into active form, via caspase-1 activity [3].

Objectives We evaluated the production of IL-1 β and TNF-α, in peripheral blood monocytes (MO) of patients affected by RA or T2DM or both diseases, in order to understand if, an alteration of the glucose metabolism may influence their pro-inflammatory status.

Methods We enrolled 10 RA patients, 10 T2DM patients and 10 patients affected by both the diseases (T2DM/RA patients), and 5 healthy controls (HC). From these patients, MO were isolated from human peripheral blood mononuclear cells using CD14 selection. After that MO were incubated with 11 mmol/1 glucose (11G) and 33 mmol/1 glucose (33G), for 24 hours, and we evaluated by ELISA the concentration of both IL-1β and TNF-α released in cultured MO supernatants, the relative mRNA expression by qRT-PCR and the western blot analysis of NLRP3. Due to the non parametric distribution of our data the Mann-Whitney U test was used as appropriate for analyses. Statistical significance was expressed by a p value <0.05.

Results Our data showed, after 24 hours of incubation with 11G, a significantly increase of IL-1β in supernatants of T2DM, RA, and T2DM/RA cultured MO, when compared with HC (p<0.01 for each comparison). Our data showed that after 24 hours of incubation with 33G a significant increase of IL-1β secretion by T2DM/RA MO of patients when compared with other groups (p<0.01 for each comparison). We observed after 24 hours of incubation with both 11G and 33G an increase of TNF-α in supernatants, in all groups when compared with HC (p<0.01 for each comparison). We did not observed significant differences in TNF-α secretion among T2DM, RA and T2DM/RA patients. The analysis of relative mRNA expression confirmed these data. Our results showed after 24 hours of incubation with both 11G and 33G a significant increase in relative NLRP3 mRNA expression when we compared T2DM/RA patients and the other groups (p<0.001 for each comparison). The results of western blot analyses for NLRP3 mirrored these data.

Conclusions Our study showed an increased production of IL-1β by MO obtained from patients affected by both RA and T2DM via NLRP3-inflammasome activation suggesting a potential IL-1β target therapy.

References

  1. Donath MY, et al. Type 2 diabetes as an inflammatory disease. Nat Rev Immunol. 2011;11:98-107.

  2. Eguchi K, et al. Macrophages and islet inflammation in type 2 diabetes. Diabetes Obes Metab. 2013;3:152-158.

  3. Schroder K, et al. The NLRP3 inflammasome: a sensor for metabolic danger? Science. 2010;327:296-300.

Disclosure of Interest None declared

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