High-density lipoprotein attenuates Th1 and th17 autoimmune responses by modulating dendritic cell maturation and...

Area of Science:

• Immunology
• Cardiovascular Biology

Background:

• Autoimmune inflammatory diseases are linked to altered high-density lipoprotein (HDL) levels and function.
• The specific role of HDL in initiating or regulating autoimmune responses remains unclear.

Purpose of the Study:

• To investigate the role of HDL in the development of autoimmune responses using apolipoprotein A-I-deficient mice.
• To explore the therapeutic potential of HDL in modulating autoimmune inflammation.

Main Methods:

• Utilized apolipoprotein A-I-deficient (apoA-I(-/-)) mice to model low HDL levels.
• Assessed arthritis severity and T cell responses (Th1, Th17) in mice.
• Investigated the effect of reconstituted HDL (rHDL) on T cell cytokine secretion and dendritic cell (DC) function in vitro.
• Analyzed the molecular mechanisms of rHDL action on DCs, including NF-κB signaling and scavenger receptor involvement.

Main Results:

• ApoA-I(-/-) mice showed increased arthritis severity and elevated Th1/Th17 cell responses.
• rHDL treatment reduced IFN-γ and IL-17 secretion from stimulated T cells.
• rHDL induced an immature phenotype in DCs, downregulating costimulatory molecules and pro-inflammatory cytokine release.
• rHDL inhibited NF-κB nuclear translocation and Myd88 mRNA levels in DCs, dependent on SR-BI and ABCA1, but not ABCG1.

Conclusions:

• HDL plays a crucial role in regulating adaptive immune responses by suppressing DC function.
• HDL's anti-inflammatory effects are mediated through the inhibition of DC maturation and T cell activation.
• HDL represents a potential therapeutic target for autoimmune inflammatory diseases.