Effects of mycoplasmal LAMPs on receptor responses to steroid hormones in mammalian cells

Many individuals are chronically infected or parasitically colonized with m ycoplasmas in their respiratory or urogenital tracts without apparent clini cal significance, However, prolonged close interaction between prokaryotic agents and eukaryotic host cells may gradually and significantly alter norm al biological or physiological properties of infected hosts. Steroid hormon es are associated with rates of cancer fort-nation in human, The purpose of this study is to establish a sensitive reporting system to examine whether mycoplasmal infections affect biological responses to steroid hormones in mammalian cells. We established pMTV-CAT stably transfected cell lines to t est the effect of mycoplasmal lipid-associated membrane proteins (LAMPs). R esults showed that LAMPs (1 mug/ml) from seven different species of human m ycoplasmas-M. penetrans, M. fermentans, M. genitalium, M. salivarium, M, pn eumoniae, M. orale, and M, hominis - had an inhibitory effect on androgen r eceptor (AR) response to Sa-dihydrotestosterone (DHT) in the E82 transfecta nts. The inhibitory effect of mycoplasmal LAMPs appeared to be dose depende nt. LAMPs from M, penetrans, M. genitalium, M. salivarium, M. pneumoniae, a nd M. orale also had an inhibitory effect on glucocorticoid receptor (GR) r esponse to hormone dexamethasone (Dex) in TSU transfectants. In contrast, L AMPs from M. fermentans and M. hominis showed a stimulatory effect on the G R response to Dex in these TSU cells. The results suggest that colonization or chronic infection by mycoplasmas may significantly affect the responses of mammalian host cells to various steroid hormones, potentially affecting rates of cancer formation.