Coupling endoplasmic reticulum stress to cell death program in isolated human pancreatic islets: effects of gene transfer of Bcl-2.
A variety of toxic insults can result in endoplasmic reticulum (ER)-stress that ultimately leads to apoptosis. beta-cells have a highly developed ER due to a great commitment to insulin production. The present study was carried out to determine the role of ER-stress in isolated human pancreatic islet apoptosis, and the potential protective effects of Bcl-2. Isolated human islets were infected with an adenoviral vector encoding Bcl-2 and then exposed to brefeldin-A, tunicamycin, A23187 and pro-inflammatory cytokines. Activation of caspase-12 was analyzed by means of Western blots. Apoptosis was evaluated using a commercial quantitative assay. ER-stress-inducers promoted caspase-12 activation and apoptosis, effect reversed by overexpression of Bcl-2. Co-localization of caspase-12 and Bcl-2 in the microsomal islet fractions were demonstrated by means of Western blots. We can conclude that the current studies highlight the importance of Bcl-2 as an anti-apoptotic protein, and shed new light on the mechanisms underlying its cytoprotective effects on pancreatic islets.
Contreras
Juan L
JL
Division of Transplantation, University of Alabama at Birmingham, 748 Lyons-Harrison Research Building, 701 19th Street South, AL 35294, Birmingham, USA. juan.contreras@ccc.uab.edu
Smyth
Cheryl A
CA
Bilbao
Guadalupe
G
Eckstein
Christopher
C
Young
Carlton J
CJ
Thompson
J Anthony
JA
Curiel
David T
DT
Eckhoff
Devin E
DE
D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western; D020126:Brefeldin A / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D053454:Caspase 12; D020169:Caspases / Q000378:metabolism; D016207:Cytokines / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D018014:Gene Transfer Techniques; D019254:Genes, bcl-2; D006801:Humans; D018836:Inflammation Mediators / Q000494:pharmacology; D007515:Islets of Langerhans / Q000187:drug effects / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000494:pharmacology / Q000502:physiology; D014415:Tunicamycin / Q000494:pharmacology
D016207:Cytokines; D018836:Inflammation Mediators; D019253:Proto-Oncogene Proteins c-bcl-2; D014415:Tunicamycin; D020126:Brefeldin A; D000001:Calcimycin; C506444:CASP12 protein, human; D053454:Caspase 12; D020169:Caspases