Niche-macrophages cell circuits in the testis – T-MAC

Macrophages (MF) populate all our tissues, from the embryonic stage to adulthood. In the testis, peritubular MF cover the surface of the seminiferous tubules while interstitial MF are interspersed between the testosterone-producing Leydig cells. The functions of these two types of MF are currently unknown. Colony stimulating factor 1 (CSF1) regulates the survival of all but a few MF. In its absence, MF cannot develop and maintain themselves, including in the testes. Interestingly, CSF1-deficient males have low testosterone levels and suffer from infertility. These results suggest that several unknown niches maintain the survival of testicular MF via CSF1 and that, in turn, testicular MF provide key signals for the development and/or maintenance of male fertility.
The testis can also be the site of infectious diseases. Since MF act as immune sentinels in many infections, they may also play a similar function in the testis.
The objectives of T-MAC are to understand how MF and their niches regulate testicular development and homeostasis as well as immune protection.