TLR4-RelA-miR-30a signal pathway regulates Th17 differentiation during experimental autoimmune encephalomyelitis development

Abstract

Background Toll-like receptor 4 (TLR4) is well known for activating the innate immune system; however, it is also highly expressed in adaptive immune cells, such as CD4+ T-helper 17 (Th17) cells, which play a key role in multiple sclerosis (MS) pathology. However, the function and governing mechanism of TLR4 in Th17 remain unclear. Methods The changes of TLR4 in CD4+ T cells from MS patients and experimental autoimmune encephalomyelitis (EAE) mice were tested. TLR4-deficient (TLR4−/−) naïve T cells were induced in vitro and transferred into Rag1−/− mice to measure Th17 differentiation and EAE pathology. DNA sequence analyses combining with deletion fragments and mutation analyses, chromatin immunoprecipitation (ChIP), and electrophoretic mobility shift assay (EMSA) were used to explore the mechanism of TLR4 signaling pathway in regulating Th17 differentiation. Results The levels of TLR4 were increased in CD4+ Th17 cells both from MS patients and EAE mice, as well as during Th17 differentiation in vitro. TLR4−/− CD4+ naïve T cells inhibited their differentiation into Th17, and transfer of TLR4−/− CD4+ naïve T cells into Rag1−/− mice was defective in promoting EAE, characterized by less demyelination and Th17 infiltration in the spinal cord. TLR4 signal enhanced Th17 differentiation by activating RelA, downregulating the expression of miR-30a, a negative regulator of Th17 differentiation. Inhibition of RelA activity increased miR-30a level, but decreased Th17 differentiation rate. Furthermore, RelA directly regulated the expression of miR-30a via specific binding to a conserved element of miR-30a gene. Conclusions TLR4−/− CD4+ naïve T cells are inadequate in differentiating to Th17 cells both in vitro and in vivo. TLR4-RelA-miR-30a signal pathway regulates Th17 differentiation via direct binding of RelA to the regulatory element of miR-30a gene. Our results indicate modulating TLR4-RelA-miR-30a signal in Th17 may be a therapeutic target for Th17-mediated neurodegeneration in neuroinflammatory diseases.

Spatiotemporally specific roles of TLR4, TNF, and IL-17A in murine endotoxin-induced inflammation inferred from analysis of dynamic networks

“…These results may indicate a broad-based, TLR4-dependent deficiency in the differentiation of these cell sub-populations. In support of this hypothesis, LPS is known to drive Th17 differentiation directly (Park et al 2015 ), and this Th17 differentiation requires TLR4 (Qu 2019 ). These findings may have clinical implications, since another study suggests that LPS promotes a Th17 bias in patients with Non-alcoholic Steatohepatitis (NASH) (Wang 2020 ).…”

Sequencing of over 100,000 individuals identifies multiple genes and rare variants associated with Crohns disease susceptibility

“…NFkB is a ubiquitous transcription factor, and its most abundant form is NFKB1 complexed together with RELA. RELA regulates the Th17 pathway in autoimmune disease models 43 , and the FOXO3-NF-κB RelA protein complexes reduce proinflammatory cell signaling and function 44 . RELA haploinsufficiency causes autosomal dominant chronic mucotaneous ulceration 45 , and RELA is a master transcriptional regulator of epithelial-mesenchymal transition in epithelial cells 46 .…”

Exploration of Prognostic Biomarkers and Therapeutic Targets in The Microenvironment of Bladder Cancer Based on CXC Chemokines

“…RELA also regulates oncogene-induced senescence to decrease the proliferation in murine Kras-driven pancreatic cancer via the CXCL1/CXCR2 axis [61]. Additionally, RELA acts as an important transcription factor in the activation and stability of regulatory T cells [62] and regulates Th17 differentiation by miR-30a in experimental autoimmune encephalomyelitis [63]. NFKB1 is involved widely in carcinogenesis, including driving tumor progression or acting as a tumor-suppressor by phosphorylation and ubiquitination pathways [64].…”