Differential influence of tacrolimus and sirolimus on mitochondrial-dependent signaling for apoptosis in pancreatic cells

Abstract

To examine and compare the mitochondria-related cellular mechanisms by which tacrolimus (TAC) or sirolimus (SIR) immunosuppressive drugs alter the pancreatic exocrine and endocrine β-cell fate. Human exocrine PANC-1 and rat endocrine insulin-secreting RIN-m5F cells and isolated rat islets were submitted to 1-100 nM TAC or SIR. In cultures, insulin secretion was measured as endocrine cell function marker. Apoptosis was quantified by annexin 5 and propidium iodide staining. Cleaved caspase-3, Bax apoptosis indicators, and p53, p21 cell cycle regulators were detected by Western blot. Cell cycle and mitochondrial membrane potential (ΔΨm) were analyzed by flow cytometry and SA-beta-galactosidase (SA-β-gal) activity by fluorescence microscopy. Only TAC reduced insulin secretion by RIN-m5F after 24 h. TAC and SIR promoted moderate apoptosis in both PANC-1 and RIN-m5F after 24 h. Apoptosis was associated with up-regulated Bax (threefold) and cleaved caspase-3 (fivefold) but only in PANC-1, while p53 and p21 were up-regulated (twofold) in both cell lines. ΔΨm was impaired only in PANC-1 by TAC and SIR. Only SIR prompted cell cycle arrest in both cell lines. The induction of a premature senescence-like phenotype was confirmed in isolated islets by SA-β-gal activity. TAC and SIR are early inducers of pancreatic cell dysfunction and apoptosis but differentially alter endocrine and exocrine cells via mitochondrial-driven pathways. In rat islets, TAC and SIR prompt a senescence-like phenotype.

Strategies based on organ decellularization and recellularization

“…Graft survival rates and insulin independence have improved, but patients are still suffering from possible life‐threatening complications, such as post‐transplantation pancreatitis after SPK or portal vein thrombosis after ITX . Furthermore, patients are confronted with the requirement for lifelong immunosuppressive therapy, which has many side‐effects .…”

The therapeutic efficacy of water-soluble coenzyme Q10 in an experimental model of tacrolimus-induced diabetes mellitus

“…This presumption may be supported by the lack of difference in cell survival or ROS production in in vitro studies of the two groups. It is well known that oxidative stress [4,24,25] and apoptosis [25][26][27] are common mechanisms of TAC-induced DM. To explain the improved hyperglycemia control by CoQ 10 -W, we evaluated the antioxidant and anti-apoptotic effects of CoQ 10 -W and CoQ 10 -L in TAC-induced pancreatic islet injury.…”

Mitochondrial Respiration Is Associated with Alloxan-Induced Mitochondrial Permeability Transition

“…In previous reports we demonstrated that alloxan induced apoptotic death in INS-1 cells (a rat pancreatic β-cell line) and that the coincident mitochondrial damage is linked to apoptosis [8], and that alloxan induces MPT that requires mitochondrial energization, oxidation of protein thiols, and matrix ATP to promote energized uptake of Ca 2+ [9]. Several studies have demonstrated theinvolvement of mitochondrial events such as activation of mitochondrial-derived factors and the decrease in mitochondrial transmembrane potential in apoptosis [10] [11]. Ubiquinone is a respiratory chain component buried within the inner membrane where it accepts two electrons from complexes I or II.…”

“…Alloxan is a mild oxidant that is easily reduced to alloxan radical by GSH or ascorbate [18] [19]. MPT can be induced by a diverse range of stimuli, including prooxidants, ganglioside GD3, fatty acids, quinone compounds and thiol oxidants [10] [12] [20] [21]. Here, we showed that mitochondrial respiration is associated with alloxan-induced MPT triggered by succinate, and that MPT should be associated with redox cycling of alloxan via an electron transfer process occurring at a quinone binding site in respiratory mitochondria.…”