Microbiota Induces Expression of Tumor Necrosis Factor in Postnatal Mouse Skin

Tumor necrosis factor (TNF) is a pleiotropic cytokine that regulates many important processes in the body. TNF production in a physiological state supports the structure of lymphoid organs and determines the development of lymphoid cells in hematopoiesis. However, chronic TNF overexpression leads to the development of various autoimmune disorders. Sites of TNF production in the naïve state remain unclear due to the lack of in vivo models. In the present study, we used TNF-2A-Kat reporter mice to monitor the expression of TNF in different tissues. Comparative analysis of tissue fluorescence in TNF-2A-Kat reporter mice and wild type mice revealed constitutive expression of TNF in the skin of naïve adult mice. In the skin of TNF-2A-Kat reporter mouse embryos, no statistically significant differences in the expression of TNF compared to wild type animals were observed. Furthermore, we established that local depletion of microflora with topical antibiotics leads to a reduction in the fluorescence signal. Thus, we assume that the skin microflora is responsible for the expression of TNF in the skin of mice.