The formation of lipid droplets favors intracellular Mycobacterium leprae survival in SW-10,non-myelinating Schwann cells

Leprosy is a chronic infectious disease that is caused by the obligate intracellular pathogen mycobacterium leprae (m.leprae),which is the leading cause of all non-traumatic peripheral neuropathies worldwide. although both myelinating and non-myelinating schwann cells are infected by m.leprae in patients with lepromatous leprosy,m.leprae preferentially invades the non-myelinating schwann cells. however,the effect of m.leprae infection on non-myelinating schwann cells has not been elucidated. lipid droplets (lds) are found in m.leprae-infected schwann cells in the nerve biopsies of lepromatous leprosy patients. m.leprae-induced ld formation favors intracellular m.leprae survival in primary schwann cells and in a myelinating schwann cell line referred to as st88-14. in the current study,we initially characterized sw-10 cells and investigated the effects of lds on m.leprae-infected sw-10 cells,which are non-myelinating schwann cells. sw-10 cells express s100,a marker for cells from the neural crest,and ngfr p75,a marker for immature or non-myelinating schwann cells. sw-10 cells,however,do not express myelin basic protein (mbp),a marker for myelinating schwann cells,and myelin protein zero (mpz),a marker for precursor,immature,or myelinating schwann cells,all of which suggests that sw-10 cells are non-myelinating schwann cells. in addition,sw-10 cells have phagocytic activity and can be infected with m. leprae. infection with m. leprae induces the formation of lds. furthermore,inhibiting the formation of m. leprae-induced ld enhances the maturation of phagosomes containing live m.leprae and decreases the atp content in the m. leprae found in sw-10 cells. these facts suggest that ld formation by m. leprae favors intracellular m. leprae survival in sw-10 cells,which leads to the logical conclusion that m.leprae-infected sw-10 cells can be a new model for investigating the interaction of m.leprae with non-myelinating schwann cells. © 2017 jin et al.