# Chemical-induced colitis lowers mitochondrial bioenergetic function in the colonic epithelium with minimal impacts on the proteome

## TL;DR

This study shows that DSS-induced colitis reduces mitochondrial function in the colon without major changes in protein levels.

## Contribution

The study reveals that DSS-induced colitis primarily affects mitochondrial respiration, especially at complex I, without significant proteomic changes.

## Key findings

- DSS treatment significantly lowers mitochondrial respiration, particularly complex I activity.
- Proteomic changes are minimal, with only NIPSNAP1 upregulated.
- Knocking down NIPSNAP1 does not rescue bioenergetic defects.

## Abstract

Dextran Sulfate Sodium (DSS) is widely used to model colitis due to its ability to disrupt the colonic epithelial barrier and trigger inflammation. While DSS is a valuable tool for studying colitis-related diseases, its impact on mitochondrial bioenergetics and the proteomic landscape of colonic tissue remains poorly understood. To address this gap, we administered 3% DSS in drinking water to C57BL/6J mice and analyzed resected colonic tissue from treated and control mice. Longitudinally opened colon segments were cleaned and subjected to high-resolution respirometry and mass spectrometry-based proteomic profiling. DSS treatment led to a global lowering of mitochondrial respiration, with the most pronounced impairments observed in complex I-supported respiration. Proteomic analysis revealed that these functional deficits occurred largely independently of changes in the mitochondrial proteome, except for an apparent upregulation of NIPSNAP1, a mitophagy-related protein. However, lentiviral knockdown of NIPSNAP1 in HCT116 cells did not rescue the observed bioenergetic defects, suggesting it is not the primary driver. Collectively, our findings show that DSS impairs mitochondrial respiration in the colon—most notably at complex I—without major alterations to the mitochondrial proteome. Given the role of mitochondrial dysfunction in various diseases, these effects should be carefully considered when using DSS-based models to study colitis pathophysiology.