Wharton’s jelly mesenchymal stem cells: Future regenerative medicine for clinical applications in mitigation of radiation injury

Figure 5 Molecular mechanism of tissue repair and regeneration by Wharton’s jelly mesenchymal stem cells. Radiation-induced reactive oxygen species (ROS) causes cellular damage. In response to Wharton’s jelly, mesenchymal stem cells (WJ-MSCs) release antioxidant enzymes [superoxide dismutase (SOD), catalase] and transfer healthy mitochondria to damaged cells. Radiation triggers the release of pro-inflammatory cytokines [e.g., tumor necrosis factor-α, interleukin (IL)-1β, interferon (IFN)-γ], causing inflammation and tissue damage. WJ-MSCs migrate to injury sites, guided by chemokine receptors and adhesion molecules. WJ-MSCs interact with T cells through cell-cell contact and soluble factors, inhibiting T-cell proliferation, inducing T-cell apoptosis, and promoting the formation of regulatory T cells. They also secrete factors like prostaglandin E2 (PGE2), hepatocyte growth factor (HGF), IL-6, IL-10, transforming growth factor (TGF) β1, soluble human leukocyte antigen (HLA)-G5, and soluble galectins (1, 3, 9), which help modulate the immune response. Additionally, WJ-MSCs prevent dendritic cell maturation, altering natural killer and B cell functions to reduce inflammation and support tissue repair. Breg: B regulatory cell; CD: Cluster of differentiation; D reg: Dendritic regulatory cell; ICAM: Intercellular adhesion molecule; PD1: Programmed death 1; PDL1: Programmed death-ligand 1; RBC: Red blood cell; TCR: T cell receptor; Th cell: T helper cell; Tregs: T regulatory cells; VCAM: Vascular cell adhesion molecule; VEGF: Vascular endothelial growth factor.