Defective lymphocyte caspase-3 expression in type 1 diabetes mellitus

Abstract

Objective: Activation-induced cell death (AICD) is a major mechanism in the regulation of peripheral tolerance and its impairment can determine the development of autoimmunity. In the present study, in order to evaluate the role of caspase-3 in type 1 diabetes mellitus (T1DM) AICD, caspase-3 expression was analyzed in peripheral blood lymphocytes from 37 new onset T1DM patients and from 36 normal control subjects (NC) in resting conditions and after anti-Fas-triggered apoptosis. Methods: Caspase-3 expression was determined by semiquantitative RT-PCR and Western blot. Apoptosis was induced in activated lymphocytes by anti-Fas monoclonal antibody and quantified by flow cytometry and morphological analysis. Results: Caspase-3 mRNA expression was reduced in resting lymphocytes in 18/37 T1DM patients and in 1/36 NC (P , 0.01). Patients studied for both Fas-mediated AICD and caspase-3 mRNA expression revealed that a reduced caspase-3 mRNA expression in resting lymphocytes occurred in all patients showing resistance to Fas-mediated apoptosis (T1DM vs NC, P , 0.02) with the exception of 3 patients who exhibited normal caspase-3 expression levels. Caspase-3 protein analysis confirmed mRNA data and showed an impaired expression of caspase-3 active form in T1DM subjects compared with NC. Conclusions: Our data show that defective expression and function of caspase-3 in peripheral lymphocytes of T1DM patients may contribute to the development of AICD resistance in type 1 diabetes.

Expresión disminuida de caspasa 3 asociada al polimorfismo del gen del antígeno-4 asociado a linfocito T-citotóxico (CTLA4) en pacientes chilenos con diabetes tipo 1

“…rev Med chile 2012; 140: 1109-1115 expresión disminuida de caspasa 3 y polimorfismo ctlA4 en dM1 -B. Angel et al Vendrame y cols 35 reportaron una expresión alterada de caspasa 3 en pacientes con DM1. Sus resultados mostraron una resistencia a la apoptosis mediada por el receptor de membrana Fas debido, al menos en un grupo de pacientes, a un defecto en la expresión de caspasa 3 (principal ejecutor de la muerte celular por apoptosis dependiente de Fas).…”

“…Sus resultados mostraron una resistencia a la apoptosis mediada por el receptor de membrana Fas debido, al menos en un grupo de pacientes, a un defecto en la expresión de caspasa 3 (principal ejecutor de la muerte celular por apoptosis dependiente de Fas). Ellos propusieron que la expresión y función defectuosa de caspasa 3 en linfocitos periféricos de pacientes con DM1 u otras enfermedades autoinmunes como tiroiditis, puede cumplir una función importante en la resistencia a la muerte celular y así contribuir al desarrollo de autoinmunidad en individuos susceptibles genéticamente 35,36 . Nuestros resultados indican que las CPMs provenientes de pacientes portadores del alelo G del polimorfismo + 49 A/G de CTLA4 mostraron una expresión reducida de caspasa 3 después de la exposición a altos niveles de glucosa.…”

“…Nuestros resultados indican que las CPMs provenientes de pacientes portadores del alelo G del polimorfismo + 49 A/G de CTLA4 mostraron una expresión reducida de caspasa 3 después de la exposición a altos niveles de glucosa. Este resultado es concordante con lo observado por Vendrame y cols 35 y podría indicar una resistencia a la muerte celular por parte del linfocito T.…”

Immunological characterisations of peripheral blood memory CD4+ T cells in children with type 1 diabetes, their non-diabetic siblings and age- and gender-matched unrelated healthy control children

“…Alterations in T cell apoptosis in T1D and other autoimmune diseases has been previously reported, and is becoming an important focus in T1D research. T cell resistance to apoptosis, resulting from suppressed caspase-3 expression [223,224] and/or genetic defects in Fas expression [225] has been suggested as for contributing to autoimmunity in patients with T1D and other autoimmune diseases. In our study, we did not observe any defect in expression of activated caspases-3 in reactivated CD4 + Tm cells from T1D patients.…”

“…However, the fate of repetitively reactivated CD4 + Tm cells in T1D still remains to be elucidated. Previous studies have shown that autoreactive T cells in T1D patient may possess multiple defects that increase their resistance to apoptosis, including suppressed Caspase-3 expression [223,224], and genetic defects in Fas (CD95) expression and function [225]. However, studies in patients with other autoimmune disorders such as coeliac disease and multiple sclerosis report a high sensitivity in reactivated CD4 + Tm cells to TCR-induced apoptosis [167,170], and studies using NOD mice also showed that pathogenic CD4 + Tm cells were prone to reactivation induced apoptosis [166].…”