Effector T Cells Promote Fibrosis in Corneal Transplantation Failure

CD4+CD25- T-Cell-Secreted IFN-γ Promotes Corneal Nerve Degeneration in Diabetic Mice

Purpose

This study aimed to explore the relationship between corneal nerve degeneration and elevated dendritic cells (DCs) in diabetic keratopathy.

Methods

Corneas from diabetic and healthy mice were analyzed using single-cell RNA sequencing. Corneal nerve density and DC and T-cell infiltration were quantified through whole-mount corneal staining. Freshly isolated mouse trigeminal ganglion (TG) neurons were co-cultured with immature DCs, mature DCs, activated CD8+ T cells, and CD4+CD25- T cells. TG neurite outgrowth was assessed to identify potential effector cells driving corneal nerve degeneration. In addition, interferon-gamma (IFN-γ) and blocking antibodies were used to evaluate their effects on TG neurite outgrowth and corneal nerve degeneration in mice.

Results

Compared with age-matched healthy mice, diabetic mice exhibited a significant reduction in corneal nerve density and sensitivity, along with increased infiltration of DCs, CD4+ T cells, and CD8+ T cells. In vitro co-culture experiments revealed that CD4+CD25- T cells, rather than DCs and CD8+ T cells, significantly inhibited TG neurite outgrowth. Among cytokines, elevated IFN-γ in diabetic corneas impaired TG neurite outgrowth and induced corneal nerve degeneration, whereas IL-4 and IL-17 had no such effect. Blocking IFN-γ alleviated CD4+CD25- T-cell-induced inhibition of TG neurite outgrowth and corneal nerve degeneration in diabetic mice.

Conclusions

CD4+CD25- T cells, but not DCs or CD8+ T cells, contribute to corneal nerve degeneration in diabetic mice, a process partially mediated by IFN-γ.

Radiation-induced fibrosis: Mechanisms and therapeutic strategies from an immune microenvironment perspective

Radiation-induced fibrosis (RIF) is a severe chronic complication of radiotherapy (RT) manifested by excessive extracellular matrix (ECM) components deposition within the irradiated area. The lung, heart, skin, jaw, pelvic organs and so on may be affected by RIF, which hampers body functions and quality of life. There is accumulating evidence suggesting that the immune microenvironment may play a key regulatory role in RIF. This article discussed the synergetic or antagonistic effects of immune cells and mediators in regulating RIF's development. Several potential preventative and therapeutic strategies for RIF were proposed based on the immunological mechanisms to provide clinicians with improved cognition and clinical treatment guidance.