Combination GLP-1RA and Low-Dose IL-2 Modulates Peripheral Immune Activation and Attenuates CNS Inflammatory Transcript Signatures In Vivo.

Immune dysregulation characterized by persistent myeloid activation and associated impairment of regulatory T cell (Treg) function contributes to inflammatory signaling across peripheral and central compartments in neurodegenerative diseases. We evaluated whether combining a glucagon-like peptide-1 receptor agonist (GLP-1RA; semaglutide) with low-dose interleukin-2 (LD-IL2) could modulate myeloid-associated transcript expression and enhance Treg-associated regulatory transcripts in a subacute lipopolysaccharide (LPS)-induced model of systemic and CNS inflammation. Mice received LPS once daily for 5 days, while GLP-1RA, LD-IL2, or combination treatment was initiated 24 h after LPS onset and continued daily. Splenic immune populations were quantified, and transcript expressions were assessed in magnetically enriched CD11b+ myeloid cells and CD4+CD25+ Tregs, as well as in cortex and hippocampus. As monotherapies, GLP-1RA reduced myeloid expansion with modest modulation of pro-inflammatory and anti-inflammatory myeloid transcripts, whereas LD-IL2 selectively enhanced Treg numbers and increased transcripts associated with Treg stability and suppressive regulation, including Il2ra (CD25), Foxp3, Ctla4, Ikzf2 (HELIOS), Entpd1 (CD39), and Nt5e (CD73). Combination treatment significantly reduced LPS-induced myeloid Il6, Il1b, and Tnf expression and increased Arg1 expression. Combination treatment further enhanced Treg-associated Il2ra (CD25), Tgfb1, and Ctla4 expression relative to monotherapies. In cortical and hippocampal tissues, combination treatment produced more robust modulation of inflammatory transcripts compared with effects observed with monotherapies, including reductions in Il6 and Il1b and increases in Cd163 and Mrc1 (CD206) expression. Together, these findings demonstrate coordinated and complementary changes in peripheral immune-cell populations and myeloid inflammatory and Treg-associated regulatory transcripts and warrant further evaluation of this combination in inflammation-driven neurodegenerative disease.