Defective lymphocyte caspase-3 expression in type 1 diabetes mellitus.
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.
Vendrame
Francesco
F
Department of Clinical Sciences-Endocrinology, University La Sapienza, Rome, Italy.
Santangelo
Carmela
C
Misasi
Roberta
R
Dionisi
Sabrina
S
Gizzi
Chiara
C
Realacci
Massimo
M
Grassetti
Daniele
D
Di Mario
Umberto
U
Dotta
Francesco
F
D000293:Adolescent; D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000201:enzymology*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008213:Lymphocyte Activation; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000201:enzymology*; D019014:fas Receptor / Q000096:biosynthesis / Q000097:blood
D012333:RNA, Messenger; D019014:fas Receptor; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases