Radiation-induced enteropathy remains a major complication after accidental or therapeutic exposure to ionizing radiation. Recent evidence suggests that intestinal microvascular damage significantly affects the development of radiation enteropathy. Mesenchymal stem cell (MSC) therapy is a promising tool to regenerate various tissues, including skin and intestine. Further, photobiomodulation (PBM), or low-level light therapy, can accelerate wound healing, especially by stimulating angiogenesis, and stem cells are particularly susceptible to PBM. Here, we explored the effect of PBM on the therapeutic potential of MSCs for the management of radiation enteropathy. In vitro, using human umbilical cord blood-derived MSCs, PBM increased proliferation and self-renewal. Intriguingly, the conditioned medium from MSCs treated with PBM attenuated irradiation-induced apoptosis and impaired tube formation in vascular endothelial cells, and these protective effects were associated with the upregulation of several angiogenic factors. In a mouse model of radiation-induced enteropathy, treatment with PBM-preconditioned MSCs alleviated mucosal destruction, improved crypt cell proliferation and epithelial barrier functions, and significantly attenuated the loss of microvascular endothelial cells in the irradiated intestinal mucosa. This treatment also significantly increased angiogenesis in the lamina propria. Together, we suggest that PBM enhances the angiogenic potential of MSCs, leading to improved therapeutic efficacy for the treatment of radiation-induced enteropathy.

Radiation-induced skin injury can take the form of serious cutaneous damage and have specific characteristics. Asymptomatic periods are classified as the latent stage. The skin barrier plays a critical role in the modulation of skin permeability and hydration and protects the body against a harsh external environment. However, an analysis on skin barrier dysfunction against radiation exposure in the latent stage has not been conducted. Thus, we investigated whether the skin barrier is impaired by irradiation in the latent stage and aimed to identify the molecules involved in skin barrier dysfunction. We analyzed skin barrier function and its components in SKH1 mice that received 20 and 40 Gy local irradiation. Increased transepidermal water loss and skin pH were observed in the latent stage of the irradiated skin. Skin barrier components, such as structural proteins and lipid synthesis enzymes in keratinocyte, increased in the irradiated group. Interestingly, we noted sebaceous gland atrophy and increased serine protease and inflammatory cytokines in the irradiated skin during the latent period. This finding indicates that the main factor of skin barrier dysfunction in the latent stage of radiation-induced skin injury is sebaceous gland deficiency, which could be an intervention target for skin barrier impairment.

Eosinophils are multifunctional granulocytes that reside constitutively within mucosal tissues, where they engage in bidirectional communication with the epithelial cells lining the respiratory and gastrointestinal (GI) tracts. Once regarded solely as terminal effectors of the type 2 immunity, eosinophils are now recognized as key regulators of epithelial homeostasis and barrier integrity. Epithelial cells initiate crosstalk by releasing the alarm cytokines such as interleukin (IL)-33, thymic stromal lymphopoietin (TSLP), and IL-25, which drive eosinophil recruitment, activation, and tissue retention. Conversely, eosinophils modulate epithelial function through the release of granule proteins, cytokines, and growth factors with both damaging and reparative consequences. In the airway, this crosstalk underpins the pathogenesis of eosinophilic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP), in part via eosinophil-derived mediators that disrupt tight junction integrity and fuel remodeling. In the GI tract, homeostatic eosinophils support villous architecture, epithelial turnover, and goblet cell differentiation through microbiota-driven IL-33 signals and neuropeptide-mediated neuroimmune pathways, whereas dysregulated crosstalk promotes eosinophilic esophagitis (EoE) and inflammatory bowel disease (IBD). This review synthesizes recent research to delineate the molecular mechanisms of eosinophil–epithelial crosstalk across mucosal compartments, highlight tissue-specific differences and shared mechanistic themes, and discuss the implications of these findings for targeted therapy.

Radiation-induced skin injury can be a serious cutaneous damage and have specific characteristics. Asymptomatic periods are classified as the latent stage. The skin barrier plays a critical role in the modulation of skin permeability and hydration and protects the body against a harsh external environment. However, an analysis on the skin barrier dysfunction against radiation exposure in the latent stage has not been conducted. Thus, we investigated whether skin barrier is impaired by irradiation in the latent stage and aimed to identify the molecules involved in skin barrier dysfunction. We analyzed skin barrier function and its components in SKH-1 mice that received 20 and 40 Gy local irradiation. Increased transepidermal water loss and skin pH were observed in the latent stage of the irradiated skin. Skin barrier components, such as structural proteins and lipid synthesis enzymes in keratinocyte, increased in the irradiated group. Interestingly, we noted sebaceous gland atrophy and increased serine protease and inflammatory cytokines in the irradiated skin during the latent period. This finding indicates that the main factor of skin barrier dysfunction in the latent stage of radiation-induced skin injury is sebaceous gland deficiency, which could be an intervention target for skin barrier impairment.