Characterization of the heterogeneity in oxidative stress and transcriptional programs within the in vivo microenvironment of ulcerative colitis

Oxidative stress exerts an essential role in the pathogenesis of ulcerative colitis (UC). This study aims to unveil the heterogeneity in oxidative stress among immune cell subpopulations in UC.

Human colon epithelial cells were exposed to 100 ng/mL LPS to stimulate UC, which were administrated with antioxidants 500 mM butylated hydroxyanisole or 20 μM N-acetylcysteine. A single-cell atlas was constructed across UC, and heterogeneous cell subpopulations were evaluated at single-cell and bulk levels.

Activation of oxidative stress and inflammatory response, enhanced migration capacity, and impaired tight junction were observed in LPS-induced UC cell models, which were ameliorated by antioxidants. Five cell types: plasma cells, T cells, myeloid cells, and B cells were clustered across UC and control gut biopsies, which were tightly interacted. Myeloid cells were sub-clustered into conventional dendritic cells, M1 macrophages, IL23R⁺ myeloid cells, mast cells, and follicular dendritic cells; T cells were sub-clustered into Th17, CD4⁺ naïve T cells, CD8⁺ cytotoxic T cells, CD4⁺ exhausted T cells, CD8⁺ memory T cells, Tregs, and Th1. The heterogeneous myeloid and T cells was confirmed at the single-cell and bulk levels. The activity of oxidative stress was heterogeneous among diverse myeloid cell or T cell subpopulations, with the strongest activity in M1 macrophages and CD4⁺ exhausted T cells, respectively. It was also found the specific transcriptional programs of M1 macrophages and CD8⁺ cytotoxic T cells.

Overall, our findings unveil the heterogeneity in oxidative stress and transcriptional programs among diverse myeloid and T cell subpopulations in UC.