Adaptation of extracellular matrix to massive small bowel resection in mice.

Background: Extracellular matrix (ECM) affects cell behavior, and vice versa. How ECM changes after small bowel resection (SBR) to support adaptive cellular processes has not been described. Here we characterize changes in ECM following SBR and integrate this with concomitant transcriptional perturbations.

Methods: A 50% proximal SBR or sham surgery was performed on mice. On postoperative day 7, ileal tissue was sequentially depleted of protein components to generate an ECM-enriched fraction. ECM was analyzed for protein composition using mass spectrometry with subsequent Ingenuity Pathway Analysis (IPA) to identify predicted pathways and upstream regulators. qPCR and RNA-sequencing (RNA-Seq) were performed to corroborate these predicted pathways.

Results: 3034 proteins were differentially regulated between sham and SBR, of which 95 were significant (P < 0.05). IPA analysis predicted PPARα agonism to be an upstream regulator of the observed proteomic changes (P < 0.001). qPCR and RNA-Seq with KEGG analysis confirmed significant engagement of the PPAR pathway (P < 0.05).

Conclusion: Transcriptional signatures of adapting bowel predict subsequent ECM changes after SBR. How ECM communicates with surrounding cells to drive adaptation and vice versa merits further investigation. Our findings thus far suggest ECM supports tissue hyperplasia and altered metabolic demand following SBR.