Understanding the pathogenesis of endometriosis through proteomics: recent advances and future prospects.

Endometriosis is a complex gynecological disease, characterized by the presence and growth of endometrial tissue outside the uterus, resulting in pelvic pain and infertility. It occurs in 10% of women in their reproductive age. The viable endometrial cells enter the peritoneal cavity by retrograde menstruation, implant, and cause lesions ectopically; depending on their ability to survive, attach, grow, and invade. These "normal" endometrial cells turn "endometriotic" apparently because of inherent abnormalities present in them. Information on these molecular abnormalities is now being sought through proteomic approaches. Recent proteome-based comparisons between the eutopic endometrium from normal women and patients with endometriosis have revealed several proteins (many of which are shown to have a role in several cancers), of which a few have been validated as potential players in the etiology of endometriosis. After an initial in-flow of information from these proteome studies of eutopic endometrium, focus now needs to be expanded to the changes in the various protein PTMs and their upstream effectors present in these tissues. Early diagnosis of endometriosis through noninvasive means is the need of the hour as well-which would require the use of the presently existing immunoassays, along with the advancing MS-based proteomics. In this review, we aim to discuss these future thrust areas of human endometriosis proteomics and also present the proteomic advances made so far in understanding the molecular basis of endometriosis.

Association of lactate, intracellular pH, and intracellular calcium during capacitation and acrosome reaction: contribution of hamster sperm dihydrolipoamide dehydrogenase, the E3 subunit of pyruvate dehydrogenase complex.

The role of dihydrolipoamide dehydrogenase (DLD), the E3 subunit of the pyruvate dehydrogenase complex (PDHc) in hamster sperm capacitation and acrosome reaction has been implicated previously. In this study, attempt has been made to understand DLD/PDHc involvement from the perspective of pyruvate/lactate metabolism. Inhibition of DLD was achieved by the use of a specific inhibitor, 5-methoxyindole-2-carboxylic acid. It was seen that 5-methoxyindole-2-carboxylic acid-treated spermatozoa with inhibited DLD (and PDHc) activity had lactate accumulation, which caused an initial lowering of the intracellular pH and calcium and an eventual block in capacitation and acrosome reaction. Collectively, the data reveal a significant contribution of the metabolic enzymes DLD and PDHc to lactate regulation in hamster spermatozoa during capacitation and acrosome reaction. Additionally, the importance of lactate regulation in the maintenance of sperm intracellular pH and calcium, two important physiologic factors essential for sperm capacitation and acrosome reaction, has also been established.

Inhibition of in vitro capacitation of hamster spermatozoa by nitric oxide synthase inhibitors.

In an attempt to understand the role of nitric oxide(NO) in sperm capacitation, in the present study, hamster spermatozoa were used to evaluate the effects of NO on motility, viability, hyperactivation, capacitation and protein tyrosine and serine phosphorylation using specific inhibitors of nitric oxide synthase (NOS); namely L-NAME (N-nito-L-aginine methyl ester) and 7-Ni (7-nitroindazole). The results indicated that L-NAME inhibits sperm motility, hyperactivation and acrosome reaction where as 7-Ni inhibits only hyperactivation and acrosome reaction thus implying that NOS inhibitors exhibit subtle differences with respect to their effects on sperm functions. This study also provides evidence that NOS inhibitors inhibit sperm capacitation by their ability to modulate protein tyrosine phosphorylation. However, the inhibitors had no effect on the protein serine phosphorylation of hamster spermatozoa during capacitation. Thus, these results indicate that NO is required