Aicda, encoding activation-induced cytidine deaminase (AID), is crucial for immunoglobulin (Ig) gene somatic hypermutation (SHM) and class switch DNA recombination (CSR). These processes are central to the maturation of effective antibody responses, occurring mainly in germinal centers. AID triggers DNA deamination, which underpins Ig variable gene conversion, isotype class switching, and some oncogenic translocations in B cell tumors [2,3].

In Aicda -deficient mice, IgA production is impaired. Feeding these mice a high-fat diet (HFD) exacerbates hyperinsulinemia, with increased gene expression of monocyte chemoattractant protein-1 in the liver, a chemokine related to hyperinsulinemia onset. However, Aicda deficiency does not lead to gut dysbiosis, though it does increase inflammatory cytokine gene expression in the ileum [1].

In conclusion, Aicda is essential for antibody-related processes like SHM and CSR. The use of Aicda-deficient mouse models has revealed its role in metabolic and inflammatory responses, specifically in the context of HFD-induced hyperinsulinemia and ileal inflammation, contributing to our understanding of related disease mechanisms.

References:

1. Tsuruta, Takeshi, Muhomah, Teresia Aluoch, Sonoyama, Kei, Katsumata, Emiko, Nishino, Naoki. 2021. Aicda deficiency exacerbates high-fat diet-induced hyperinsulinemia but not gut dysbiosis in mice. In Nutrition research (New York, N.Y.), 93, 15-26. doi:10.1016/j.nutres.2021.06.009. https://pubmed.ncbi.nlm.nih.gov/34332207/

2. Di Noia, Javier M, Neuberger, Michael S. . Molecular mechanisms of antibody somatic hypermutation. In Annual review of biochemistry, 76, 1-22. doi:. https://pubmed.ncbi.nlm.nih.gov/17328676/

3. Xu, Zhenming, Pone, Egest J, Al-Qahtani, Ahmed, Zan, Hong, Casali, Paolo. . Regulation of aicda expression and AID activity: relevance to somatic hypermutation and class switch DNA recombination. In Critical reviews in immunology, 27, 367-97. doi:. https://pubmed.ncbi.nlm.nih.gov/18197815/