Virus in the pathogenesis of inflammatory bowel disease: role of Toll-like receptor 7/8/3

Asadzadeh Aghdaei, Hamid; Jamshidi, Negar; Chaleshi, Vahid; Jamshidi, Nazanin; Sadeghi, Amir; Norouzinia, Mohsen; Zali, Mohammad Reza

The pathogenesis of inflammatory bowel disease (IBD) is influenced by immune system malfunction, particularly innate immune receptors such as toll-like receptors. Furthermore, it is critical to investigate the extremely close association between viruses and IBD incidence. Toll-like receptors (TLRs) 3, 5, and 7 are involved in antiviral immune responses. Finding a relationship between TLR-related virus and IBD is important not only for understanding the disease pathogenesis, but also for developing effective therapies. It has been shown that influenza is expressed more severely in patients with IBD who use immune system inhibitors, and the influenza vaccine is less effective in these patients. In dendritic cells, TLR7 and TLR8 regulate the production of interferons (IFNs) and inflammatory mediators. COVID-19 causes the production of IL-6, possibly due to the induction of TLR pathways. TLR activation by SARS-CoV-2 causes inflammation and IL-1 production, which induces the production of IL-6. Understanding TLR-associated viruses’ molecular mechanisms can greatly help improve the quality of life of people with IBD. Therefore, the present study reviewed the role of TLR7, 8, and 3 in inflammatory bowel disease as well as their association with viral infections and evaluated different antagonists for the treatment of IBD.