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Effects of soluble epoxide hydrolase deficiency on acute pancreatitis in mice.

Bettaieb A, Chahed S, Tabet G, Yang J, Morisseau C, Griffey S, Hammock BD, Haj FG - PLoS ONE (2014)

Bottom Line: In addition, amylase and lipase levels were lower in cerulein-treated Ephx2 KO mice compared with controls.Moreover, pancreatic mRNA and serum concentrations of the inflammatory cytokines IL-1B and IL-6 were lower in cerulein-treated Ephx2 KO mice compared with controls.Conclusions -These findings demonstrate a novel role for sEH in the progression of cerulein- and arginine-induced AP.

View Article: PubMed Central - PubMed

Affiliation: Department of Nutrition, University of California Davis, Davis, California, United States of America.

ABSTRACT

Background: Acute pancreatitis (AP) is a frequent gastrointestinal disorder that causes significant morbidity, and its incidence has been progressively increasing. AP starts as a local inflammation in the pancreas that often leads to systemic inflammatory response and complications. Soluble epoxide hydrolase (sEH) is a cytosolic enzyme whose inhibition in murine models has beneficial effects in inflammatory diseases, but its significance in AP remains unexplored.

Methodology/principal findings: To investigate whether sEH may have a causal role in AP we utilized Ephx2 knockout (KO) mice to determine the effects of sEH deficiency on cerulein- and arginine-induced AP. sEH expression increased at the protein and messenger RNA levels, as well as enzymatic activity in the early phase of cerulein- and arginine-induced AP in mice. In addition, amylase and lipase levels were lower in cerulein-treated Ephx2 KO mice compared with controls. Moreover, pancreatic mRNA and serum concentrations of the inflammatory cytokines IL-1B and IL-6 were lower in cerulein-treated Ephx2 KO mice compared with controls. Further, Ephx2 KO mice exhibited decreased cerulein- and arginine-induced NF-κB inflammatory response, MAPKs activation and decreased cell death. Conclusions -These findings demonstrate a novel role for sEH in the progression of cerulein- and arginine-induced AP.

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Related in: MedlinePlus

sEH deficiency decreases cerulein- and arginine-induced MAPKs signaling.A) Total pancreas lysates from wild type mice without (n = 6) and with (n = 9) cerulein, and Ephx2 KO mice without (n = 6) and with (n = 9) cerulein were immunoblotted for pERK1/2, pp38, pJNK1/2 and their respective unphosphorylated proteins and Tubulin as a loading control. Representative immunoblots (n = 2–3 samples per group) are shown. Bar graphs represent normalized data for pERK/ERK, pp38/p38, and pJNK/JNK, and presented as means±SEM (AU: arbitrary units). (*: P≤0.05; **: P≤0.01) indicate significant difference between mice without and with cerulein administration, and (#: P≤0.05; ##: P≤0.01) indicate significant difference between WT and KO mice. B) Total pancreas lysates from wild type mice without (n = 8) and with (n = 8) arginine administration for the indicated times, and Ephx2 KO mice without (n = 8) and with (n = 8) arginine administration were immunoblotted for pERK1/2, pp38, pJNK1/2 and their respective unphosphorylated proteins and Tubulin. Representative immunoblots (n = 2–3 samples per group) are shown. Bar graphs represent normalized data for pERK/ERK, pp38/p38, and pJNK/JNK, and presented as means±SEM. (**: P≤0.01) indicate significant difference between mice without and with arginine administration, and (##: P≤0.01) indicates significant difference between WT and KO mice.
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pone-0113019-g004: sEH deficiency decreases cerulein- and arginine-induced MAPKs signaling.A) Total pancreas lysates from wild type mice without (n = 6) and with (n = 9) cerulein, and Ephx2 KO mice without (n = 6) and with (n = 9) cerulein were immunoblotted for pERK1/2, pp38, pJNK1/2 and their respective unphosphorylated proteins and Tubulin as a loading control. Representative immunoblots (n = 2–3 samples per group) are shown. Bar graphs represent normalized data for pERK/ERK, pp38/p38, and pJNK/JNK, and presented as means±SEM (AU: arbitrary units). (*: P≤0.05; **: P≤0.01) indicate significant difference between mice without and with cerulein administration, and (#: P≤0.05; ##: P≤0.01) indicate significant difference between WT and KO mice. B) Total pancreas lysates from wild type mice without (n = 8) and with (n = 8) arginine administration for the indicated times, and Ephx2 KO mice without (n = 8) and with (n = 8) arginine administration were immunoblotted for pERK1/2, pp38, pJNK1/2 and their respective unphosphorylated proteins and Tubulin. Representative immunoblots (n = 2–3 samples per group) are shown. Bar graphs represent normalized data for pERK/ERK, pp38/p38, and pJNK/JNK, and presented as means±SEM. (**: P≤0.01) indicate significant difference between mice without and with arginine administration, and (##: P≤0.01) indicates significant difference between WT and KO mice.

Mentions: Mitogen-activated protein kinases (MAPKs) including p38, ERK1/2 and JNK1/2 are induced rapidly and transiently during experimental AP in rodents [42]. This activation is believed to be a component of the cellular stress response in the onset of inflammation in the pancreas. Treatment with EETs reduces inflammation-induced p38 phosphorylation to mediate anti-inflammatory properties [43]. Cerulein administration led to increased phosphorylation of ERK, p38 and JNK in control mice and that was significantly decreased in Ephx2 KO mice (Fig. 4A). Similarly, arginine administration increased ERK, p38 and JNK phosphorylation in control mice and that was significantly decreased in Ephx2 KO mice (Fig. 4B). 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 [44], [45]. Accordingly, we assessed cerulein-induced expression of initiator and effector Caspases in control versus Ephx2 KO mice. Cerulein caused pro-Caspases 8, 9 and 3 cleavage and an increase in the cleavage fragments and induced cleavage of Caspase 3 substrate; poly (ADP-ribose) polymerase (PARP) (Fig. 5A). sEH deficiency decreased cleaved Caspase 8, 9 and 3 and PARP expression indicative of decreased apoptosis (Fig. 5A). In addition, comparable findings were observed in arginine-treated cohort (Fig. 5B). Collectively, these findings demonstrate decreased MAPKs signaling and cell death upon sEH deficiency during the early phase of cerulein- and arginine-induced AP.


Effects of soluble epoxide hydrolase deficiency on acute pancreatitis in mice.

Bettaieb A, Chahed S, Tabet G, Yang J, Morisseau C, Griffey S, Hammock BD, Haj FG - PLoS ONE (2014)

sEH deficiency decreases cerulein- and arginine-induced MAPKs signaling.A) Total pancreas lysates from wild type mice without (n = 6) and with (n = 9) cerulein, and Ephx2 KO mice without (n = 6) and with (n = 9) cerulein were immunoblotted for pERK1/2, pp38, pJNK1/2 and their respective unphosphorylated proteins and Tubulin as a loading control. Representative immunoblots (n = 2–3 samples per group) are shown. Bar graphs represent normalized data for pERK/ERK, pp38/p38, and pJNK/JNK, and presented as means±SEM (AU: arbitrary units). (*: P≤0.05; **: P≤0.01) indicate significant difference between mice without and with cerulein administration, and (#: P≤0.05; ##: P≤0.01) indicate significant difference between WT and KO mice. B) Total pancreas lysates from wild type mice without (n = 8) and with (n = 8) arginine administration for the indicated times, and Ephx2 KO mice without (n = 8) and with (n = 8) arginine administration were immunoblotted for pERK1/2, pp38, pJNK1/2 and their respective unphosphorylated proteins and Tubulin. Representative immunoblots (n = 2–3 samples per group) are shown. Bar graphs represent normalized data for pERK/ERK, pp38/p38, and pJNK/JNK, and presented as means±SEM. (**: P≤0.01) indicate significant difference between mice without and with arginine administration, and (##: P≤0.01) indicates significant difference between WT and KO mice.
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Related In: Results  -  Collection

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pone-0113019-g004: sEH deficiency decreases cerulein- and arginine-induced MAPKs signaling.A) Total pancreas lysates from wild type mice without (n = 6) and with (n = 9) cerulein, and Ephx2 KO mice without (n = 6) and with (n = 9) cerulein were immunoblotted for pERK1/2, pp38, pJNK1/2 and their respective unphosphorylated proteins and Tubulin as a loading control. Representative immunoblots (n = 2–3 samples per group) are shown. Bar graphs represent normalized data for pERK/ERK, pp38/p38, and pJNK/JNK, and presented as means±SEM (AU: arbitrary units). (*: P≤0.05; **: P≤0.01) indicate significant difference between mice without and with cerulein administration, and (#: P≤0.05; ##: P≤0.01) indicate significant difference between WT and KO mice. B) Total pancreas lysates from wild type mice without (n = 8) and with (n = 8) arginine administration for the indicated times, and Ephx2 KO mice without (n = 8) and with (n = 8) arginine administration were immunoblotted for pERK1/2, pp38, pJNK1/2 and their respective unphosphorylated proteins and Tubulin. Representative immunoblots (n = 2–3 samples per group) are shown. Bar graphs represent normalized data for pERK/ERK, pp38/p38, and pJNK/JNK, and presented as means±SEM. (**: P≤0.01) indicate significant difference between mice without and with arginine administration, and (##: P≤0.01) indicates significant difference between WT and KO mice.
Mentions: Mitogen-activated protein kinases (MAPKs) including p38, ERK1/2 and JNK1/2 are induced rapidly and transiently during experimental AP in rodents [42]. This activation is believed to be a component of the cellular stress response in the onset of inflammation in the pancreas. Treatment with EETs reduces inflammation-induced p38 phosphorylation to mediate anti-inflammatory properties [43]. Cerulein administration led to increased phosphorylation of ERK, p38 and JNK in control mice and that was significantly decreased in Ephx2 KO mice (Fig. 4A). Similarly, arginine administration increased ERK, p38 and JNK phosphorylation in control mice and that was significantly decreased in Ephx2 KO mice (Fig. 4B). 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 [44], [45]. Accordingly, we assessed cerulein-induced expression of initiator and effector Caspases in control versus Ephx2 KO mice. Cerulein caused pro-Caspases 8, 9 and 3 cleavage and an increase in the cleavage fragments and induced cleavage of Caspase 3 substrate; poly (ADP-ribose) polymerase (PARP) (Fig. 5A). sEH deficiency decreased cleaved Caspase 8, 9 and 3 and PARP expression indicative of decreased apoptosis (Fig. 5A). In addition, comparable findings were observed in arginine-treated cohort (Fig. 5B). Collectively, these findings demonstrate decreased MAPKs signaling and cell death upon sEH deficiency during the early phase of cerulein- and arginine-induced AP.

Bottom Line: In addition, amylase and lipase levels were lower in cerulein-treated Ephx2 KO mice compared with controls.Moreover, pancreatic mRNA and serum concentrations of the inflammatory cytokines IL-1B and IL-6 were lower in cerulein-treated Ephx2 KO mice compared with controls.Conclusions -These findings demonstrate a novel role for sEH in the progression of cerulein- and arginine-induced AP.

View Article: PubMed Central - PubMed

Affiliation: Department of Nutrition, University of California Davis, Davis, California, United States of America.

ABSTRACT

Background: Acute pancreatitis (AP) is a frequent gastrointestinal disorder that causes significant morbidity, and its incidence has been progressively increasing. AP starts as a local inflammation in the pancreas that often leads to systemic inflammatory response and complications. Soluble epoxide hydrolase (sEH) is a cytosolic enzyme whose inhibition in murine models has beneficial effects in inflammatory diseases, but its significance in AP remains unexplored.

Methodology/principal findings: To investigate whether sEH may have a causal role in AP we utilized Ephx2 knockout (KO) mice to determine the effects of sEH deficiency on cerulein- and arginine-induced AP. sEH expression increased at the protein and messenger RNA levels, as well as enzymatic activity in the early phase of cerulein- and arginine-induced AP in mice. In addition, amylase and lipase levels were lower in cerulein-treated Ephx2 KO mice compared with controls. Moreover, pancreatic mRNA and serum concentrations of the inflammatory cytokines IL-1B and IL-6 were lower in cerulein-treated Ephx2 KO mice compared with controls. Further, Ephx2 KO mice exhibited decreased cerulein- and arginine-induced NF-κB inflammatory response, MAPKs activation and decreased cell death. Conclusions -These findings demonstrate a novel role for sEH in the progression of cerulein- and arginine-induced AP.

Show MeSH
Related in: MedlinePlus