Chronic alcohol exposure affects pancreatic acinar mitochondrial thiamin pyrophosphate uptake: studies with mouse 266-6 cell line and primary cells

Srinivasan, Padmanabhan; Nabokina, Svetlana M.; Said, Hamid M.

doi:10.1152/ajpgi.00226.2015

Cited by 16 publications

(26 citation statements)

References 45 publications

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“…266-6 cells retain a partially differentiated phenotype and express several digestive-enzymes 20 . They respond to carbachol and CCK and have been used to investigate the physiology and pathology of the pancreas 21 . We observed that high dose of LLOMe treatment leads to significant cell death in 266-6 cell line through necrosis as indicated by increased LDH release (Supplementary figure-7).…”

Section: Resultsmentioning

confidence: 99%

Release of Cathepsin B in Cytosol Causes Cell Death in Acute Pancreatitis

et al. 2016

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BACKGROUND & AIMS Experimental studies in acute pancreatitis (AP) suggest strong association of acinar cell injury with cathepsin-B dependent intracellular activation of trypsin. However, the molecular events subsequent to trypsin activation and their role, if any, in cell death have not been studied. In this study, we have explored, for the first time, intra-acinar events downstream of trypsin activation which lead to acinar cell death. METHODS Acinar cells prepared from the pancreas of rats or mice (wild-type, trypsinogen-7 or cathepsin-B deleted) were stimulated with supramaximal caerulein and cytosolic activity of cathepsin-B and trypsin was evaluated. Permeabilzed acini were used to understand the differential role of cytosolic trypsin vs cytosolic cathepsin-B in activation of apoptosis. Cell death was evaluated by measuring specific markers for apoptosis and necrosis. RESULTS Both in vitro and in vivo studies suggest that during AP cathepsin-B leaks into the cytosol from co-localized organelles, through a mechanism dependent on active trypsin. Cytosolic cathepsin-B but not trypsin activates the intrinsic pathway of apoptosis through cleavage of bid and activation of bax. Finally, excessive release of cathepsin-B into the cytosol can lead to cell death through necrosis. CONCLUSIONS This is the first report which defines the role of trypsin in AP and demonstrates that cytosolic cathepsin-B but not trypsin activates cell death pathways. This is also the first report to suggest that trypsin is requisite for AP only because it causes release of cathepsin-B into the cytosol.

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Section: Resultsmentioning

confidence: 99%

Release of Cathepsin B in Cytosol Causes Cell Death in Acute Pancreatitis

et al. 2016

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“…Control animals received regular (no nicotine) water. After 4 weeks the mice were euthanized and the pancreas was removed and primary PAC were isolated by a collagenase type-V (Sigma, St. Louis, MO) digestion method as described previously [ 36 – 38 ]. Freshly isolated PAC were used for uptake analysis on the day of isolation with a portion stored at −80°C for protein, mRNA expression and firefly luciferase analyses.…”

Section: Methodsmentioning

confidence: 99%

Chronic Nicotine Exposure In Vivo and In Vitro Inhibits Vitamin B1 (Thiamin) Uptake by Pancreatic Acinar Cells

et al. 2015

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Thiamin (vitamin B1), a member of the water-soluble family of vitamins, is essential for normal cellular functions; its deficiency results in oxidative stress and mitochondrial dysfunction. Pancreatic acinar cells (PAC) obtain thiamin from the circulation using a specific carrier-mediated process mediated by both thiamin transporters -1 and -2 (THTR-1 and THTR-2; encoded by the SLC19A2 and SLC19A3 genes, respectively). The aim of the current study was to examine the effect of chronic exposure of mouse PAC in vivo and human PAC in vitro to nicotine (a major component of cigarette smoke that has been implicated in pancreatic diseases) on thiamin uptake and to delineate the mechanism involved. The results showed that chronic exposure of mice to nicotine significantly inhibits thiamin uptake in murine PAC, and that this inhibition is associated with a marked decrease in expression of THTR-1 and THTR-2 at the protein, mRNA and hnRNAs level. Furthermore, expression of the important thiamin-metabolizing enzyme, thiamin pyrophosphokinase (TPKase), was significantly reduced in PAC of mice exposed to nicotine. Similarly, chronic exposure of cultured human PAC to nicotine (0.5 μM, 48 h) significantly inhibited thiamin uptake, which was also associated with a decrease in expression of THTR-1 and THTR-2 proteins and mRNAs. This study demonstrates that chronic exposure of PAC to nicotine impairs the physiology and the molecular biology of the thiamin uptake process. Furthermore, the study suggests that the effect is, in part, mediated through transcriptional mechanism(s) affecting the SLC19A2 and SLC19A3 genes.

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“…Pair feeding of transgenic mice carrying the SLC25A19 promoter with thiamin-DEF and -OS diets. We pair fed (for 6 wk) transgenic mice recently generated and characterized in our laboratory (38) that carry the human SLC25A19 gene promoter [i.e., 1,080 bp (Ϫ860 to ϩ220) fragment fused with firefly luciferase reporter genes], with a thiamin-DEF or -OS diet. These two diets were identical (AIN-93G purified thiamin-deficient rodent diet; Dyets, Bethlehem, PA), but the latter one contained 6 mg/kg of added thiamin (26,32) (animals were fed this thiamin deficient diet for the specified period to develop thiamin deficiency).…”

Section: Methodsmentioning

confidence: 99%

“…In addition, we have cloned and characterized the SLC25A19 promoter and have identified an important role for the nuclear factor NF-Y in driving its basal activity (24). Furthermore, we have investigated the effect of certain environmental/external factors (specifically chronic exposure to alcohol and to components of cigarette smoke) on TPP uptake by PAC mitochondria and delineated the molecular mechanisms involved in the observed effects (38,39). However, little is currently known about possible effect of the prevailing thiamin level on TPP uptake by PAC mitochondria.…”

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confidence: 99%

Adaptive regulation of pancreatic acinar mitochondrial thiamin pyrophosphate uptake process: possible involvement of epigenetic mechanism(s)

Sabui

Subramanian

Kapadia

et al. 2017

American Journal of Physiology-Gastrointestinal and Liver Physi

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The essentiality of thiamin stems from its roles as a cofactor [mainly in the form of thiamin pyrophosphate (TPP)] in critical metabolic reactions including oxidative energy metabolism and reduction of cellular oxidative stress. Like other mammalian cells, pancreatic acinar cells (PAC) obtain thiamin from their surroundings and convert it to TPP; mitochondria then take up TPP by a carrier-mediated process that involves the mitochondrial TPP (MTPP) transporter (MTPPT; product of gene). Previous studies have characterized different physiological/biological aspects of the MTPP uptake process, but little is known about its possible adaptive regulation. We addressed this issue using pancreatic acinar 266-6 cells (PAC 266-6) maintained under thiamin-deficient (DEF) and oversupplemented (OS) conditions, as well as thiamin-DEF and -OS transgenic mice carrying the promoter. We found that maintaining PAC 266-6 under the thiamin-DEF condition leads to a significant induction in mitochondrial [H]TPP uptake, as well as in the level of expression of the MTPPT protein and mRNA compared with thiamin-OS cells. Similar findings were observed in mitochondria from thiamin-DEF mice compared with thiamin-OS. Subsequently, we demonstrated that adaptive regulation of MTTP protein was partly mediated via transcriptional mechanism(s) via studies with PAC 266-6 transfected with the promoter and transgenic mice carrying the promoter. This transcriptional regulation appeared to be, at least in part, mediated via epigenetic mechanism(s) involving histone modifications. These studies report, for the first time, that the PAC mitochondrial TPP uptake process is adaptively regulated by the prevailing thiamin level and that this regulation is transcriptionally mediated and involves epigenetic mechanism(s). Our findings show, for the first time, that the mitochondrial thiamin pyrophosphate (MTPP) uptake process is adaptively regulated by the prevailing thiamin level in pancreatic acinar cells and this regulation is mediated, at least in part, by transcriptional and epigenetic mechanism(s) affecting the promoter.

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Chronic alcohol exposure affects pancreatic acinar mitochondrial thiamin pyrophosphate uptake: studies with mouse 266-6 cell line and primary cells

Cited by 16 publications

References 45 publications

Release of Cathepsin B in Cytosol Causes Cell Death in Acute Pancreatitis

Release of Cathepsin B in Cytosol Causes Cell Death in Acute Pancreatitis

Chronic Nicotine Exposure In Vivo and In Vitro Inhibits Vitamin B1 (Thiamin) Uptake by Pancreatic Acinar Cells

Adaptive regulation of pancreatic acinar mitochondrial thiamin pyrophosphate uptake process: possible involvement of epigenetic mechanism(s)

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