The effects of STAT1 dysfunction on the gut

Abstract

Introduction: Mutations in the signal transducer and activator of transcription1 (STAT1) have been associated with a variety of clinical patterns. Interestingly patients with heterozygous mutations in the DNA binding domain (DBD) of STAT1 suffer acute and chronic colitis.Methods: To further analyze the role of STAT1 deficiency in intestinal inflammation, we employed protein expression analysis of total and activated STAT1 in intestinal biopsy samples from 2 patients with heterozygous mutations in the DBD of the STAT1 gene.Results: Both patients showed clinical and histological features of colitis. Total and activated STAT1 were decreased in duodenal and colonic enterocytes, and total STAT1 was found to be mislocalized in aggregates subapically. In addition, intestinal biopsy samples showed decreased numbers of lymphocytes. Patient-derived lymphoblasts demonstrated lack of viability and high susceptibility for cell death.Conclusion: STAT1 expression and distribution in the gut of patients with mutations in the DBD are abnormal, suggesting a primary role of STAT1 dysfunction in enterocytes in addition to the secondary effect of aberrant inflammation.Statement of novelty: Colitis associated with STAT1 mutations appears to have unique features distinct from typical inflammatory bowel disease.