Male germ cell specific sulfogalactoglycerolipid is recognized and degraded by mycoplasmas associated with male infertility

Abstract

Sulfogalactosylglycerolipid (SGG) is the major mammalian male germ cell glycolipid and has been implicated in sperm/egg binding. Mycoplasma pulmonis, a species of Mollicutes, is associated with male infertility in rodents. Purified SGG incubated in the presence of M. pulmonis was enzymatically degraded by both desulfation and deacylation. Desulfation occurred primarily at alkaline pH, and deacylation also increased with increased pH, indicating that these represent novel enzymatic activities. Digestion was facilitated, but not dependent on, the presence of detergent. Rat spermatozoa exposed to M. pulmonis showed a reduction in SGG content which was particularly marked for cauda (mature) spermatozoa. With the aid of tlc overlay binding procedure, intact M. pulmonis were found to bind specifically to sulfated glycolipids and thus SGG may provide the cell membrane receptor for this organism. The topology of mycoplasma binding to rat sperm was consistent with the known topology of sperm SGG. The reduced binding (and subsequent digestion) of caput spermatozoan SGG correlates with the membrane colocalization of SGG and its endogenous binding protein at this stage. Separation of SGG and its binding protein during epididymal sperm maturation appears to facilitate M. pulmonis binding to and digestion of cauda sperm SGG. The binding and degradation of the sperm SGG by M. pulmonis may play a role in the induction of infertility which follows infection with these organisms by interfering in sperm/egg receptor recognition.

Catabolism in Mollicutes

“…The ability of M . pulmonis to produce male infertility in rodents may also be associated with its ability to specifically degrade sulphogalactosylglycerolipid (SGG), the major mammalian male germ cell glycolipid, which is implicated in binding to egg cells (Lingwood et al, 1990); SGG underwent both desulphation and deacylation.…”

Characteristics of Mycoplasma hominis adhesion

“…In common with the patient isolates of M. hominis, however, 100 pg of fucoidan per ml inhibited 80% of PG21 attachment. The reference strain's comparative inability to adhere avidly to cell culture monolayers, as well as the inhibitory effects of low-MW DS, instead of high-MW DS, on its adherence, suggests that significant changes in the (8), as does the related genital mollicutes Ureaplasma urealyticum (human origin) and U. diversum (bovine origin) (7). The increasing body of evidence suggests that these sulfated glycolipids represent readily available and important receptors for the adherence of pathogens (4,5).…”

Mycoplasmes génitaux

“…Les auteurs en concluent que les mycoplasmes ne constituent qu'une simple colonisation ; • différents travaux et notamment ceux de l'équipe canadienne de C.A. Lingwood [17] ont établi que les mycoplasmes induisaient, chez l'animal et dans l'espèce humaine, des altérations fonctionnelles du spermatozoïde (par l'intermédiaire notamment des sulfoglycolipides). Il en résulterait une inhibition de la capacité de reconnaissance des ovocytes.…”