Pparα knockout in mice increases the Th17 development by facilitating the IKKα/RORγt and IKKα/Foxp3 complexes

Area of Science:

• Immunology
• Metabolism
• Molecular Biology

Background:

• Helper CD4+ T cell type 17 (Th17) and regulatory CD4+ T cells (Tregs) balance is crucial for immune homeostasis.
• Metabolic factors are key regulators of T cell differentiation and function.
• Dysregulation of Th17/Treg balance is implicated in various immune and autoimmune diseases.

Purpose of the Study:

• To investigate the role of peroxisome proliferator of activated receptor-alpha (Pparα) in regulating Th17 cell differentiation.
• To elucidate the molecular mechanisms by which Pparα influences Th17 cell development and function.
• To evaluate the therapeutic potential of targeting Pparα in autoimmune diseases.

Main Methods:

• Pparα ablation in mice.
• Analysis of Th17 cell differentiation and function in vitro and in vivo.
• Investigation of molecular interactions involving IκB kinase-alpha (IKKα), RORγt, and Foxp3.
• Assessment of disease pathology in a murine experimental autoimmune encephalomyelitis (EAE) model.

Main Results:

• Pparα deficiency enhances Th17 cell differentiation and increases pro-Th17 factor HIF-1α.
• IKKα expression and nuclear localization are increased upon Pparα ablation.
• IKKα directly interacts with RORγt to promote Il17a gene expression and with Foxp3 to induce its degradation.
• Pparα deficiency exacerbates EAE pathology in mice.

Conclusions:

• Pparα acts as a suppressor of Th17 cell differentiation through modulation of IKKα, RORγt, and Foxp3.
• Pparα deficiency promotes autoimmune responses and disease severity.
• Pparα represents a potential therapeutic target for autoimmune and inflammatory conditions.