The mast cell mediator histamine affects β-INS-1 832/13 function and survival, a role in the pathogenesis of diabetes

Abstract

Abstract

The mast cell mediator histamine affects INS-1 832/13 function and survival, a role in the pathogenesis of diabetes

Background: Type 2 diabetes (T2D) is characterized by β-cells dysfunction and insulin resistance within the target tissues. Recent reports suggest a role of inflammation in the disease pathogenesis both in animal models and in human patients. Mast cells and their inflammatory mediators are key players in allergic responses. While these cells also may play a role in the regulation of the immune system, little is known about their contribution to diabetes pathogenesis.

Aims: The aim of this study was to investigate the effect of histamine on β-cell function and survival.

Methods: INS-1 (832/13) cells were co-cultured with histamine at different concentrations in the presence or absence of pro-inflammatory cytokines for 48h prior to evaluate cell apoptosis by flow cytometry. Insulin secretion was performed to study β cell function. Quantitative RT-PCR assay was performed to explore the expression of histamine receptors on INS-1(832/13) cells. Finally, the frequency of mast cells in the pancreatic islets of leptin receptor deficient (db/db) mice was investigated using flow cytometry.

Results: Histamine alone was found to have minimal effect on β cell survival. However, histamine potentiates cytokine-mixture-induced apoptosis (TNF-α, INF-γ and IL1-β) in INS-1 (832/13) cells. Nevertheless, when INS-1 (832/13) cells were culture only in the presence of IL1-β, histamine had a protective effect. Histamine might be implicated in β cell dysfunction. INS-1 (832/13) cells express specifically histamine receptor 3 (HR3), which mediates the effects of histamine in these cells. Finally, we found increased mast cell recruitment in pancreatic islets of db/db mice.

Conclusions: Histamine has a role in β cell survival and it is implicated in β cell dysfunction. These preliminary findings suggest a role of mast cell in the pathogenesis of T2D and in the response of pancreatic islet to inflammatory stimuli.

Abstract

The mast cell mediator histamine is involve in T2D pathogenicity

Diabetes mellitus is a common metabolic disorder which is characterized by high glucose levels in blood and urine. Diabetes is one of the most expanding diseases in the world today. There are 2 major types of diabetes; type 2 diabetes (T2D) contributes with up to 90% of all diabetes subtypes. Patients with T2D compose up to 150 million today and are expected to expand to 300 million year 2025. Type 1 diabetes is characterized by deficiency of insulin secretion where the immune system destroys the insulin-producing beta cells, while T2D is characterized by insulin resistance and disrupted beta cell functions. Insulin resistance refers to a defect in the receptors on the cells which responds to insulin rather than a defect in insulin production. Recently, many reports have suggested also a role of immune system in the pathogenesis of this subtype as well. Low grade inflammation seems to be behind the reduced insulin sensitivity in the target tissues. Different cells from the immune system have been indicated to participate in the observed inflammation. Macrophages, mast cells (MCs) and released inflammatory mediators seemed to be important factors participating in the development of T2D. A recent study reveals that the cytokine interleukine 1 beta (IL-1β, a soluble mediator) plays an important role in β-cell dysfunction. Lately, several reports have highlighted the role of MCs, with a negative action during the development of T2D. These reports show a higher accumulation of MCs in T2D than in normal control patients. However, the role of MCs still needs to be clarified. Histamine is first phase mediator that is secreted by MCs, with its well known action during allergic reaction. In this work we aimed to investigate the role of histamine on β-cells survival and function in T2D using two different models: the rat insulin-secreting β-cell line INS-1 (823/13) and a mouse diabetic model.

In vitro we demonstrated that histamine has a minimal effect on β-cells survival when no stress was introduce to the cell culture. However, histamine did induce β-cells death within inflamed environment. Surprisingly, histamine could rescue INS-1 (823/13) cells from IL-1β induced cell death. Despite that histamine may slightly affect β-cell survival, it could strongly influence insulin secretion. Histamine mediated its effect via histamine 3 receptor, because the inhibition of this receptor abolished its protective effect from apoptosis. Interestingly, the results of ex vivo study indicated an increased in the frequency of MCs in the pancreatic islets of T2D animal model, which confirmed the results of our in vitro study. Thus, these data suggest a role for MCs in the pathogenesis of T2D, and open the door for new therapeutic strategies in this field.



Advisors: Corrado Cilio, PhD, MD, professor of Paediatrics and Wiaam Badn, PhD
Cellular Autoimmunity Unit, LUDC, CRC, Malmö
Faculty of Medicine, Lund University
Degree project 60 credits in Molecular Biology, Medical Biology;2014
Department of Biology, Lund University

*Subject of degree project: Cellular and Molecular Immunology

• author: AL Asfoor, Shefaa A.ALQaher
• supervisor: Corrado Cilio
• organization: Degree Projects in Molecular Biology
• course: MOBT14 20122
• year: 2014
• type: H2 - Master's Degree (Two Years)
• subject: Biology and Life Sciences
• language: English
• id: 4433967
• date added to LUP: 2014-05-05 15:19:03
• date last changed: 2014-05-05 15:19:03