Vitamin D immune modulation of the anti-inflammatory effects of HDL-associated proteins

Abstract

Vitamin D is a crucial element in bone metabolism and plays a role in innate immunity and inflammation suppression. Deficiency in this vitamin leads to disturbances in many biological functions, including the lipid profile. The decrease in HDL levels is associated with disruptions in its function and dynamic modifications in its components, such as apolipoproteins, including ApoM, ApoA-1, and ApoD. Consequently, the anti-inflammatory potential of HDL and HDL-associated proteins is reduced, resulting in heightened inflammation. However, the relationship between modifications in lipid profile, apolipoproteins, inflammation, and vitamin D remains unclear. This review highlights the connection between vitamin D status and its possible effects on the lipid profile, specifically HDL-associated proteins.

Keywords: ApoA-1; ApoM; HDL; Immune modulation; Inflammation; Vitamin D.

Fig. 1

The biogenesis of HDL and RCT. Created by Hanaa Mousa using the BioRender website. Upon the interaction of ApoA-1 and ABCA1, the resulting complex is catalyzed by the LCAT enzyme, forming a discoidal HDL. SR-B1 mediates cholesterol efflux from macrophages and tissues into discoidal high-density lipoprotein (HDL). Another interaction with LCAT formed the mature HDL. CETP facilitates the exchange of cholesteryl esters from HDL particles with the triglycerides in LDL, VLDL, and Chylomicrons. The liver takes the cholesterol via the LDL receptor. Note: Figures 1, and 3 Created with BioRender.com

Fig. 2

3D structure of ApoM PDB file 2WEW as a lipid carrier generated using Chimera. The Lipocalin fold, consisting of eight β-strands forming a β-barrel and an α-helix with the calyix carrying myristic acid ligand, is shown. A: 3D structure with Ribon presentation. B: 3D structure with surface presentation. The signaling peptide tail is not cleaved, as shown at the bottom of the 3D figure. (Figure 2 generated using Chimera)

Fig. 3

illustrates the effect of vitamin D on the different HDL-associated proteins, eventually suppressing inflammation. Note: Figures 1, and 3 Created with BioRender.com