Limits...
Pancreatic T cell protein-tyrosine phosphatase deficiency ameliorates cerulein-induced acute pancreatitis.

Bettaieb A, Xi Y, Hosein E, Coggins N, Bachaalany S, Wiede F, Perez S, Griffey SM, Sastre J, Tiganis T, Haj FG - Cell Commun. Signal (2014)

Bottom Line: T-cell protein tyrosine phosphatase (TCPTP) is implicated in inflammatory signaling but its significance in AP remains unclear.Amylase and lipase levels were lower in cerulein-treated panc-TCPTP KO mice compared with controls.These findings revealed a novel role for pancreatic TCPTP in the progression of cerulein-induced AP.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nutrition, University of California Davis, One Shields Ave, 3135 Meyer Hall, Davis, CA 95616, USA. fghaj@ucdavis.edu.

ABSTRACT

Background: Acute pancreatitis (AP) is a common clinical problem whose incidence has been progressively increasing in recent years. Onset of the disease is trigged by intra-acinar cell activation of digestive enzyme zymogens that induce autodigestion, release of pro-inflammatory cytokines and acinar cell injury. T-cell protein tyrosine phosphatase (TCPTP) is implicated in inflammatory signaling but its significance in AP remains unclear.

Results: In this study we assessed the role of pancreatic TCPTP in cerulein-induced AP. TCPTP expression was increased at the protein and messenger RNA levels in the early phase of AP in mice and rats. To directly determine whether TCPTP may have a causal role in AP we generated mice with pancreatic TCPTP deletion (panc-TCPTP KO) by crossing TCPTP floxed mice with Pdx1-Cre transgenic mice. Amylase and lipase levels were lower in cerulein-treated panc-TCPTP KO mice compared with controls. In addition, pancreatic mRNA and serum concentrations of the inflammatory cytokines TNFα and IL-6 were lower in panc-TCPTP KO mice. At the molecular level, panc-TCPTP KO mice exhibited enhanced cerulein-induced STAT3 Tyr705 phosphorylation accompanied by a decreased cerulein-induced NF-κB inflammatory response, and decreased ER stress and cell death.

Conclusion: These findings revealed a novel role for pancreatic TCPTP in the progression of cerulein-induced AP.

Show MeSH

Related in: MedlinePlus

Regulation of cerulein-induced ER stress and apoptosis by TCPTP. Total pancreas lysates from control without (n = 9) and with (n = 12) cerulein and panc-TCPTP KO without (n = 7) and with (n = 9) cerulein were immunoblotted for pPERK and peIF2α and their respective unphosphorylated proteins, cleaved Caspases 8, 9 and 3, PARP and Tubulin as a loading control. Bar graphs represent normalized data for pPERK/PERK, peIF2α/eIF2α and Caspase 8, 9, 3 and PARP/Tubulin as means ± SEM. (*: P ≤ 0.05; **: P ≤ 0.01) indicates significant difference between saline- and cerulein-injected mice, and (#: P ≤ 0.05; ##: P ≤ 0.01) indicates significant difference between WT and KO mice.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4016516&req=5

Figure 5: Regulation of cerulein-induced ER stress and apoptosis by TCPTP. Total pancreas lysates from control without (n = 9) and with (n = 12) cerulein and panc-TCPTP KO without (n = 7) and with (n = 9) cerulein were immunoblotted for pPERK and peIF2α and their respective unphosphorylated proteins, cleaved Caspases 8, 9 and 3, PARP and Tubulin as a loading control. Bar graphs represent normalized data for pPERK/PERK, peIF2α/eIF2α and Caspase 8, 9, 3 and PARP/Tubulin as means ± SEM. (*: P ≤ 0.05; **: P ≤ 0.01) indicates significant difference between saline- and cerulein-injected mice, and (#: P ≤ 0.05; ##: P ≤ 0.01) indicates significant difference between WT and KO mice.

Mentions: When the folding capacity of the ER is exceeded, misfolded proteins accumulate and lead to ER stress [53]. Cells use adaptive mechanisms to mitigate ER stress known as the unfolded protein response (UPR) [54]. UPR is triggered by transmembrane sensors such as PKR-like ER-regulated kinase (PERK) that detect unfolded proteins in the ER and convey information through their cytosolic domain [55]. ER stress is implicated in the pathophysiology of pancreatitis [56]. Further, we previously demonstrated that TCPTP knockdown in the glucose-responsive MIN6 β-cells attenuated PERK-eIF2α signaling [35]. In line with these findings, pancreatic TCPTP deficiency attenuated cerulein-induced PERK Thr980 and eukaryotic translation initiation factor 2α (eIF2α) Ser51 phosphorylation compared with controls (Figure 5). The UPR is deployed by cells as a compensatory mechanism to restore homeostasis, but if it fails then apoptosis commences [57]. After exposure to apoptotic stimuli, cells activate initiator Caspases (Caspases 8 and 9) that proteolytically cleave and activate effector Caspases (Caspases 3 and 7) to dismantle dying cells [58,59]. Accordingly, we assessed cerulein-induced expression of initiator and effector Caspases in control versus panc-TCPTP KO mice. Cerulein caused pro-Caspases 8, 9 and 3 cleavage and cleavage of poly ADP ribose polymerase (PARP) (Figure 5). TCPTP deficiency decreased cleaved Caspase 8, 9 and 3 expression as well as PARP indicative of decreased apoptosis (Figure 5). Collectively, these findings demonstrate decreased inflammatory signaling, and decreased ER stress and cell death upon pancreatic TCPTP deficiency during the early phase of cerulein-induced AP.


Pancreatic T cell protein-tyrosine phosphatase deficiency ameliorates cerulein-induced acute pancreatitis.

Bettaieb A, Xi Y, Hosein E, Coggins N, Bachaalany S, Wiede F, Perez S, Griffey SM, Sastre J, Tiganis T, Haj FG - Cell Commun. Signal (2014)

Regulation of cerulein-induced ER stress and apoptosis by TCPTP. Total pancreas lysates from control without (n = 9) and with (n = 12) cerulein and panc-TCPTP KO without (n = 7) and with (n = 9) cerulein were immunoblotted for pPERK and peIF2α and their respective unphosphorylated proteins, cleaved Caspases 8, 9 and 3, PARP and Tubulin as a loading control. Bar graphs represent normalized data for pPERK/PERK, peIF2α/eIF2α and Caspase 8, 9, 3 and PARP/Tubulin as means ± SEM. (*: P ≤ 0.05; **: P ≤ 0.01) indicates significant difference between saline- and cerulein-injected mice, and (#: P ≤ 0.05; ##: P ≤ 0.01) indicates significant difference between WT and KO mice.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4016516&req=5

Figure 5: Regulation of cerulein-induced ER stress and apoptosis by TCPTP. Total pancreas lysates from control without (n = 9) and with (n = 12) cerulein and panc-TCPTP KO without (n = 7) and with (n = 9) cerulein were immunoblotted for pPERK and peIF2α and their respective unphosphorylated proteins, cleaved Caspases 8, 9 and 3, PARP and Tubulin as a loading control. Bar graphs represent normalized data for pPERK/PERK, peIF2α/eIF2α and Caspase 8, 9, 3 and PARP/Tubulin as means ± SEM. (*: P ≤ 0.05; **: P ≤ 0.01) indicates significant difference between saline- and cerulein-injected mice, and (#: P ≤ 0.05; ##: P ≤ 0.01) indicates significant difference between WT and KO mice.
Mentions: When the folding capacity of the ER is exceeded, misfolded proteins accumulate and lead to ER stress [53]. Cells use adaptive mechanisms to mitigate ER stress known as the unfolded protein response (UPR) [54]. UPR is triggered by transmembrane sensors such as PKR-like ER-regulated kinase (PERK) that detect unfolded proteins in the ER and convey information through their cytosolic domain [55]. ER stress is implicated in the pathophysiology of pancreatitis [56]. Further, we previously demonstrated that TCPTP knockdown in the glucose-responsive MIN6 β-cells attenuated PERK-eIF2α signaling [35]. In line with these findings, pancreatic TCPTP deficiency attenuated cerulein-induced PERK Thr980 and eukaryotic translation initiation factor 2α (eIF2α) Ser51 phosphorylation compared with controls (Figure 5). The UPR is deployed by cells as a compensatory mechanism to restore homeostasis, but if it fails then apoptosis commences [57]. After exposure to apoptotic stimuli, cells activate initiator Caspases (Caspases 8 and 9) that proteolytically cleave and activate effector Caspases (Caspases 3 and 7) to dismantle dying cells [58,59]. Accordingly, we assessed cerulein-induced expression of initiator and effector Caspases in control versus panc-TCPTP KO mice. Cerulein caused pro-Caspases 8, 9 and 3 cleavage and cleavage of poly ADP ribose polymerase (PARP) (Figure 5). TCPTP deficiency decreased cleaved Caspase 8, 9 and 3 expression as well as PARP indicative of decreased apoptosis (Figure 5). Collectively, these findings demonstrate decreased inflammatory signaling, and decreased ER stress and cell death upon pancreatic TCPTP deficiency during the early phase of cerulein-induced AP.

Bottom Line: T-cell protein tyrosine phosphatase (TCPTP) is implicated in inflammatory signaling but its significance in AP remains unclear.Amylase and lipase levels were lower in cerulein-treated panc-TCPTP KO mice compared with controls.These findings revealed a novel role for pancreatic TCPTP in the progression of cerulein-induced AP.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Nutrition, University of California Davis, One Shields Ave, 3135 Meyer Hall, Davis, CA 95616, USA. fghaj@ucdavis.edu.

ABSTRACT

Background: Acute pancreatitis (AP) is a common clinical problem whose incidence has been progressively increasing in recent years. Onset of the disease is trigged by intra-acinar cell activation of digestive enzyme zymogens that induce autodigestion, release of pro-inflammatory cytokines and acinar cell injury. T-cell protein tyrosine phosphatase (TCPTP) is implicated in inflammatory signaling but its significance in AP remains unclear.

Results: In this study we assessed the role of pancreatic TCPTP in cerulein-induced AP. TCPTP expression was increased at the protein and messenger RNA levels in the early phase of AP in mice and rats. To directly determine whether TCPTP may have a causal role in AP we generated mice with pancreatic TCPTP deletion (panc-TCPTP KO) by crossing TCPTP floxed mice with Pdx1-Cre transgenic mice. Amylase and lipase levels were lower in cerulein-treated panc-TCPTP KO mice compared with controls. In addition, pancreatic mRNA and serum concentrations of the inflammatory cytokines TNFα and IL-6 were lower in panc-TCPTP KO mice. At the molecular level, panc-TCPTP KO mice exhibited enhanced cerulein-induced STAT3 Tyr705 phosphorylation accompanied by a decreased cerulein-induced NF-κB inflammatory response, and decreased ER stress and cell death.

Conclusion: These findings revealed a novel role for pancreatic TCPTP in the progression of cerulein-induced AP.

Show MeSH
Related in: MedlinePlus