MAP kinase inhibitor PD98059 regulates Th1, Th9, Th17, and natural T regulatory cells in an experimental autoimmune encephalomyelitis mouse model of multiple sclerosis.

Experimental autoimmune encephalitis (EAE), an animal model of multiple sclerosis (MS), provides significant insights into the mechanisms that initiate and drive autoimmunity. MS is a chronic autoimmune disease of the central nervous system, characterized by inflammatory infiltration associated with demyelination. T lymphocyte cells play a crucial role in MS, whereas natural T regulatory (nTreg) cells prevent autoimmune inflammation by suppressing lymphocyte activity. This study sought to investigate the role of PD98059, a selective MAP kinase inhibitor, in Th1, Th9, Th17, and nTreg cells using the SJL/J mouse model of EAE. Following EAE development, the mice were intraperitoneally administered PD98059 (5 mg/kg for two weeks) daily. We evaluated the effects of PD98059 on Th1 (IFN-γ and T-bet), Th9 (IL-9 and IRF4), Th17 (IL-17A and RORγT), and nTreg (FoxP3 and Helios) cells in the spleen using flow cytometry. Moreover, we explored the effects of PD98059 on the IFN-γ, T-bet, IL-9, IRF4, IL-17A, RORγT, FoxP3, and Helios mRNA and protein levels in brain tissues using qRT-PCR and Western blot analyses. PD98059 treatment significantly decreased the proportion of CD4+IFN-γ+, CD4+T-bet+, CD4+IL-9+, CD4+IRF4+, CD4+IL-17A+, CD4+RORγT+, CD4+IL-17A+, and CD4+RORγT+ cells while increasing that of CD4+FoxP3+ and CD4+Helios+ cells. In addition, PD98059 administration decreased the mRNA and protein levels of IFN-γ, T-bet, IL-9, IRF4, IL-17A, and RORγT but increased those of FoxP3 and Helios in the brain tissue of EAE mice. Our findings suggest that PD98059 corrects immune dysfunction in EAE mice, which is concurrent with the modulation of multiple signaling pathways.

Imbalance in pro-inflammatory and anti-inflammatory cytokines milieu in B cells of children with autism.

B cells play multiple roles in preservation of healthy immune system including management of immune responses by expression of pro- and anti-inflammatory cytokines. Several earlier studies have documented that B cells express both pro-inflammatory cytokines such as IL-6, TNF-α as well as anti-inflammatory cytokines such as IL-10. However, it is yet to be examined whether these pro-/anti-inflammatory cytokines are expressed in B cells of children with autism spectrum disorder (ASD). Pathophysiology of ASD begins in early childhood and is characterized by repetitive/restricted behavioral patterns, and dysfunction in communal/communication skills. ASD pathophysiology also has a strong component of immune dysfunction which has been highlighted in numerous earlier publications. In this study, we specifically explored pro-/anti-inflammatory cytokines (IL-6, IL-17A, IFN-γ, TNF-α, IL-10) in B cells of ASD subjects and compared them typically developing control (TDC) children. Present study shows that inflammatory cytokines such as IL-6 and TNF-α are elevated in B cells of ASD subjects, while anti-inflammatory cytokine, IL-10 is decreased in ASD group when compared to TDC group. Further, TLR4 activation by its ligand, lipopolysaccharide (LPS) further upregulates inflammatory potential of B cells from ASD group by increasing IL-6 expression, whereas LPS has no significant effect on IL-10 expression in ASD group. Furthermore, LPS-induced inflammatory signaling of IL-6 in B cells of ASD subjects was partially mitigated by the pretreatment with NF-kB inhibitor. Present study propounds the idea that B cells could be crucial players in causing immune dysfunction in ASD subjects through an imbalance in expression of pro-/anti-inflammatory cytokines.