Impairment of the intestinal epithelium barrier through alteration of proliferation and differentiation balance in alcohol use disorder

Figure 4 Dysregulation of the Wnt pathway in alcohol use disorder through CD44. A-D: Principal component analysis of bulk transcriptomic and proteomic data. At transcriptional level, a subset of alcohol use disorder (AUD) patients clusters closely with healthy subjects (A), whereas proteomic data (B) reveal a clear separation between both groups. Gene ontology dysregulation of the canonical Wnt signaling pathway on the transcriptomic (C) and protein (D) level. Transcriptomics, controls/healthy (n = 15); AUD (n = 43). Proteomics, controls/healthy (n = 7); AUD (n = 15); E: Multiplex immunofluorescence staining of duodenal biopsies using E-cadherin (green) for epithelium, Ki67 (red) for proliferating cells, CD44 (purple) as a Wnt/β-catenin target gene, lysozyme (yellow) for Paneth cells, and DAPI (blue) for nuclei; F: Quantification of the number of CD44⁺ cells at the crypt base. Overall CD44 expression increased in AUD patients, with proliferating, CD44⁺/Ki67⁺ double-positive cells, being significantly elevated in both AUD subgroups; G: Quantification of CD44⁺ cells in the transit amplifying zone. Only a very low number of cells (less than 10%) stained positive for CD44 with numbers tending to be slightly higher in AUD patients with an altered morphology (AUD altered). Data are presented as mean ± SD. Scale bar (200 μm). Healthy (n = 8); AUD normal (n = 8); AUD altered (n = 7). AUD: Alcohol use disorder.