Ligustilide prevents thymic immune senescence by regulating Thymosin β15-dependent spatial distribution of thymic epithelial cells

Thymosin β4 Regulates the Differentiation of Thymocytes by Controlling the Cytoskeletal Rearrangement and Mitochondrial Transfer of Thymus Epithelial Cells

The thymus is one of the most crucial immunological organs, undergoing visible age-related shrinkage. Thymic epithelial cells (TECs) play a vital role in maintaining the normal function of the thymus, and their degeneration is the primary cause of age-induced thymic devolution. Thymosin β4 (Tβ4) serves as a significant important G-actin sequestering peptide. The objective of this study was to explore whether Tβ4 influences thymocyte differentiation by regulating the cytoskeletal rearrangement and mitochondrial transfer of TECs. A combination of H&E staining, immunofluorescence, transmission electron microscopy, RT-qPCR, flow cytometry, cytoskeletal immunolabeling, and mitochondrial immunolabeling were employed to observe the effects of Tβ4 on TECs' skeleton rearrangement, mitochondrial transfer, and thymocyte differentiation. The study revealed that the Tβ4 primarily regulates the formation of microfilaments and the mitochondrial transfer of TECs, along with the formation and maturation of double-negative cells (CD4-CD8-) and CD4 single-positive cells (CD3+TCRβ+CD4+CD8-) thymocytes. This study suggests that Tβ4 plays a crucial role in thymocyte differentiation by influencing the cytoskeletal rearrangement and mitochondrial transfer of TECs. These effects may be associated with Tβ4's impact on the aggregation of F-actin. This finding opens up new avenues for research in the field of immune aging.

Th22 is the effector cell of thymosin β15-induced hair regeneration in mice

BACKGROUND

Thymosin beta family has a significant role in promoting hair regeneration, but which type of T cells play a key role in this process has not been deeply studied. This research aimed to find out the subtypes of T cell that play key role in hair regeneration mediated by thymosin beta 15 (Tβ15).

METHODS

Ready-to-use adenovirus expressing mouse Tmsb15b (thymosin beta 15 overexpression, Tβ15 OX) and lentivirus-Tβ15 short hairpin RNA (Tβ15 sh) were used to evaluate the role of Tβ15 in hair regeneration and development. The effect of Th22 cells on hair regeneration was further studied by optimized Th22-skewing condition medium and IL-22 binding protein (IL-22BP, an endogenous antagonist of IL-22, also known as IL-22RA2) in both ex vivo culture C57BL/6J mouse skin and BALB/c nude mice transplanted with thymus organoid model.

RESULTS

The results show that Tβ15, the homologous of Tβ4, can promote hair regeneration by increasing the proliferation activity of hair follicle cells. In addition, high-level expression of Tβ15 can not only increase the number of Th22 cells around hair follicles but also accelerate the transformation of hair follicles to maturity. Consistent with the expected results, when the IL-22BP inhibitor was used to interfere with Th22, the process of hair regeneration was blocked.

CONCLUSIONS

In conclusion, Th22 is the key effector cell of Tβ15 inducing hair regeneration. Both Tβ15 and Th22 may be the potential drug targets for hair regeneration.