Th17 involvement in nonalcoholic fatty liver disease progression to non-alcoholic steatohepatitis

Figure 1 Interleukin-17 signaling cascade and amplification loop. IL-17 upregulates the production of pro inflammatory cytokines IL-6 and IL-23 through a complex intracellular signal involving IL-17 RA downstream Act1, MAPK and C/EBP transcription factors and kinases. IL-6 and IL-23 after binding their receptors, stimulate IL-17 production by PI3K and JAK/STAT3 that release NF-κB to translocate to the nucleus. IL-17: Interleukin-17; Act1: Activator 1; JAK/STAT3: Janus kinase/signal transducer and activator of transcription 3; PI3K: Phosphoinositide-3-kinase.

Figure 2 T cell differentiation and plasticity. A naïve CD4 T cell differentiates into different T effector cell subsets depending on the cytokines present in the enviroment. Effector T cells secrete their characteristic cytokines represented in red. In the presence of pro-inflammatory IL-6, already differentiated Tregs can switch their phenotipe to Th17 and secrete IL-17. IL-17: Interleukin-17; Treg: Regulatory T cells; TGF-β: Transforming growth factor β; IFN-γ: Interferon-γ.