The muscle regeneration marker FOXP3 is associated with muscle injury in Duchenne muscular dystrophy

Abstract

Background

In Duchenne muscular dystrophy (DMD), the immune system cells (ISC) synthesize molecules to regulate inflammation, a process needed to regenerate muscle. The relationship between those molecules and the muscle injury is unknown. Monocytes belonging to ISC are regulated by omega-3 fatty acids (ω-3 LCPUFAs) in DMD, but whether those fatty acids influence other ISC like T-cells is unknown.

Objective

We analyzed the expression of the muscle regeneration markers (FOXP3 and AREG) in circulating leukocytes of DMD patients with different lower limb muscle functions and whether ω-3 LCPUFAs regulate the expression of those markers, and the populations of circulating T-cells, their intracellular cytokines, and disease progression (CD69 and CD49d) markers.

Methods

This placebo-controlled, double-blind, randomized study was conducted in DMD boys supplemented with ω-3 LCPUFAs (n = 18) or placebo (sunflower oil, n = 13) for six months. FOXP3 and AREG mRNA expression in leukocytes, immunophenotyping of T-cell populations, CD49d and CD69 markers, and intracellular cytokines in blood samples were analyzed at baseline and months 1, 2, 3, and 6 of supplementation.

Results

Patients with assisted ambulation expressed higher (P = 0.015) FOXP3 mRNA levels than ambulatory patients. The FOXP3 mRNA expression correlated (Rho = -0.526, P = 0.03) with the Vignos scale score at month six of supplementation with ω-3 LCPUFAs. CD49d + CD8 + T-cells population was lower (P = 0.037) in the ω −3 LCPUFAs group than placebo at month six of supplementation.

Conclusion

FOXP3 is highly expressed in circulating leukocytes of DMD patients with the worst muscle function. Omega-3 LCPUFAs might modulate the synthesis of the adhesion marker CD49d + CD8 + T-cells, but their plausible impact on FOXP3 needs more research.