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Updated: Aug 29, 2026
Murine Model of Intestinal Ischemia-reperfusion Injury
Published on: May 11, 2016
Mitogen-activated protein kinases regulate COX-2 and mucosal recovery in ischemic-injured porcine ileum
Donnie E Shifflett1, Samuel L Jones, Adam J Moeser
1Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
Abstract:
Mitogen-activated protein kinase (MAPK) pathways transduce signals from a diverse array of extracellular stimuli. The three primary MAPK-signaling pathways are the extracellular regulated kinases (ERK1/2), p38 MAPK, and c-Jun NH(2)-terminal kinase (JNK). Previous research in our laboratory has shown that COX-2-elaborated prostanoids participate in recovery of mucosal barrier function in ischemic-injured porcine ileum. Because COX-2 expression is regulated in part by MAPKs, we postulated that MAPK pathways would play an integral role in recovery of injured mucosa. Porcine mucosa was subjected to 45 min of ischemia, after which tissues were mounted in Ussing chambers, and transepithelial electrical resistance (TER) was monitored as an index of recovery of barrier function. Treatment of tissues with the p38 MAPK inhibitor SB-203580 (0.1 mM) or the ERK1/2 inhibitor PD-98059 (0.1 mM) abolished recovery. Western blot analysis revealed that SB-203580 inhibited upregulation of COX-2 that was observed in untreated ischemic-injured mucosa, whereas PD-98059 had no effect on COX-2 expression. Inhibition of TER recovery by SB-203580 or PD-98059 was overcome by administration of exogenous prostaglandin E(2) (1 microM). The JNK inhibitor SP-600125 (0.1 mM) significantly increased TER and resulted in COX-2 upregulation. COX-2 expression appears to be positively and negatively regulated by the p38 MAPK and the JNK pathways, respectively. Alternatively, ERK1/2 appear to be involved in COX-2-independent reparative events that remain to be defined.
Insights
Mitogen-activated protein kinase (MAPK) pathways are crucial for intestinal mucosal repair after injury. The p38 MAPK pathway promotes healing by upregulating COX-2, while ERK1/2 and JNK pathways have distinct roles in this recovery process.
Area of Science:
- Cell Signaling
- Gastrointestinal Physiology
- Molecular Biology
Background:
- Mitogen-activated protein kinase (MAPK) pathways are key signal transducers for various extracellular stimuli.
- Previous studies indicated that cyclooxygenase-2 (COX-2)-derived prostanoids aid in restoring mucosal barrier function following ischemic injury.
- COX-2 expression is partially regulated by MAPKs, suggesting their involvement in mucosal repair.
Purpose of the Study:
- To investigate the role of MAPK pathways (ERK1/2, p38 MAPK, JNK) in the recovery of injured porcine intestinal mucosa.
- To determine the specific involvement of these MAPK pathways in COX-2 expression and prostaglandin E(2) (PGE(2)) mediated mucosal repair.
Main Methods:
- Porcine intestinal mucosa was subjected to ischemia and subsequently mounted in Ussing chambers to measure transepithelial electrical resistance (TER) as a barrier function indicator.
- Specific inhibitors for p38 MAPK (SB-203580), ERK1/2 (PD-98059), and JNK (SP-600125) were used to assess their effects on TER recovery and COX-2 expression.
- Western blot analysis was performed to quantify COX-2 upregulation in response to ischemia and inhibitor treatments.
- The impact of exogenous prostaglandin E(2) on TER recovery was evaluated in the presence of MAPK inhibitors.
Main Results:
- Inhibition of p38 MAPK or ERK1/2 pathways abolished the recovery of mucosal barrier function (TER).
- p38 MAPK inhibition prevented the ischemia-induced upregulation of COX-2, while ERK1/2 inhibition had no effect on COX-2 levels.
- Exogenous prostaglandin E(2) restored TER recovery that was blocked by p38 MAPK or ERK1/2 inhibitors.
- JNK inhibition enhanced TER and led to COX-2 upregulation, suggesting a negative regulatory role.
Conclusions:
- The p38 MAPK pathway plays a critical role in intestinal mucosal repair by positively regulating COX-2 expression and facilitating prostaglandin-mediated recovery.
- The ERK1/2 pathway is involved in COX-2-independent mechanisms of mucosal repair.
- The JNK pathway appears to negatively regulate COX-2 expression during mucosal healing.
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