Vaginal lipidomics of women with vulvovaginal candidiasis and cytolytic vaginosis: A non-targeted LC-MS pilot study.

OBJECTIVE: To characterize the lipid profile in vaginal discharge of women with vulvovaginal candidiasis, cytolytic vaginosis, or no vaginal infection or dysbiosis. DESIGN: Cross-sectional study. SETTING: Genital Infections Ambulatory, Department of Tocogynecology, University of Campinas, Campinas, São Paulo-Brazil. SAMPLE: Twenty-four women were included in this study: eight with vulvovaginal candidiasis, eight with cytolytic vaginosis and eight with no vaginal infections or dysbiosis (control group). METHODS: The lipid profile in vaginal discharge of the different study groups was determined by liquid chromatography-mass spectrometry and further analyzed with MetaboAnalyst 3.0 platform. MAIN OUTCOME MEASURES: Vaginal lipids concentration and its correlation with vulvovaginal candidiasis and cytolytic vaginosis. RESULTS: PCA, PLS-DA and hierarchical clustering analyses indicated 38 potential lipid biomarkers for the different groups, correlating with oxidative stress, inflammation, apoptosis and integrity of the vaginal epithelial tissue. Among these, greater concentrations were found for Glycochenodeoxycholic acid-7-sulfate, O-adipoylcarnitine, 1-eicosyl-2-heptadecanoyl-glycero-3-phosphoserine, undecanoic acid, formyl dodecanoate and lipoic acid in the vulvovaginal candidiasis group; N-(tetradecanoyl)-sphinganine, DL-PPMP, 1-oleoyl-cyclic phosphatidic, palmitic acid and 5-aminopentanoic acid in the cytolytic vaginosis group; and 1-nonadecanoyl-glycero-3-phosphate, eicosadienoic acid, 1-stearoyl-cyclic-phosphatidic acid, 1-(9Z,12Z-heptadecadienoyl)-glycero-3-phosphate, formyl 9Z-tetradecenoate and 7Z,10Z-hexadecadienoic acid in the control group. CONCLUSIONS: Lipids related to oxidative stress and apoptosis were found in higher concentrations in women with vulvovaginal candidiasis and cytolytic vaginosis, while lipids related to epithelial tissue integrity were more pronounced in the control group. Furthermore, in women with cytolytic vaginosis, we observed higher concentrations of lipids related to bacterial overgrowth.

Protein Disulfide Isomerase Modulates the Activation of Thyroid Hormone Receptors.

Thyroid hormone receptors (TRs) are responsible for mediating thyroid hormone (T3 and T4) actions at a cellular level. They belong to the nuclear receptor (NR) superfamily and execute their main functions inside the cell nuclei as hormone-regulated transcription factors. These receptors also exhibit so-called "non-classic" actions, for which other cellular proteins, apart from coregulators inside nuclei, regulate their activity. Aiming to find alternative pathways of TR modulation, we searched for interacting proteins and found that PDIA1 interacts with TRß in a yeast two-hybrid screening assay. The functional implications of PDIA1-TR interactions are still unclear; however, our co-immunoprecipitation (co-IP) and fluorescence assay results showed that PDI was able to bind both TR isoforms in vitro. Moreover, T3 appears to have no important role in these interactions in cellular assays, where PDIA1 was able to regulate transcription of TRα and TRß-mediated genes in different ways depending on the promoter region and on the TR isoform involved. Although PDIA1 appears to act as a coregulator, it binds to a TR surface that does not interfere with coactivator binding. However, the TR:PDIA1 complex affinity and activation are different depending on the TR isoform. Such differences may reflect the structural organization of the PDIA1:TR complex, as shown by models depicting an interaction interface with exposed cysteines from both proteins, suggesting that PDIA1 might modulate TR by its thiol reductase/isomerase activity.

A draft of the human septin interactome.

BACKGROUND: Septins belong to the GTPase superclass of proteins and have been functionally implicated in cytokinesis and the maintenance of cellular morphology. They are found in all eukaryotes, except in plants. In mammals, 14 septins have been described that can be divided into four groups. It has been shown that mammalian septins can engage in homo- and heterooligomeric assemblies, in the form of filaments, which have as a basic unit a hetero-trimeric core. In addition, it has been speculated that the septin filaments may serve as scaffolds for the recruitment of additional proteins. METHODOLOGY/PRINCIPAL FINDINGS: Here, we performed yeast two-hybrid screens with human septins 1-10, which include representatives of all four septin groups. Among the interactors detected, we found predominantly other septins, confirming the tendency of septins to engage in the formation of homo- and heteropolymeric filaments. CONCLUSIONS/SIGNIFICANCE: If we take as reference the reported arrangement of the septins 2, 6 and 7 within the heterofilament, (7-6-2-2-6-7), we note that the majority of the observed interactions respect the "group rule", i.e. members of the same group (e.g. 6, 8, 10 and 11) can replace each other in the specific position along the heterofilament. Septins of the SEPT6 group preferentially interacted with septins of the SEPT2 group (p<0.001), SEPT3 group (p<0.001) and SEPT7 group (p<0.001). SEPT2 type septins preferentially interacted with septins of the SEPT6 group (p<0.001) aside from being the only septin group which interacted with members of its own group. Finally, septins of the SEPT3 group interacted preferentially with septins of the SEPT7 group (p<0.001). Furthermore, we found non-septin interactors which can be functionally attributed to a variety of different cellular activities, including: ubiquitin/sumoylation cycles, microtubular transport and motor activities, cell division and the cell cycle, cell motility, protein phosphorylation/signaling, endocytosis, and apoptosis.

On the denaturation mechanisms of the ligand binding domain of thyroid hormone receptors.

The ligand binding domain (LBD) of nuclear hormone receptors adopts a very compact, mostly alpha-helical structure that binds specific ligands with very high affinity. We use circular dichroism spectroscopy and high-temperature molecular dynamics simulations to investigate unfolding of the LBDs of thyroid hormone receptors (TRs). A molecular description of the denaturation mechanisms is obtained by molecular dynamics simulations of the TRalpha and TRbeta LBDs in the absence and in the presence of the natural ligand Triac. The simulations show that the thermal unfolding of the LBD starts with the loss of native contacts and secondary structure elements, while the structure remains essentially compact, resembling a molten globule state. This differs from most protein denaturation simulations reported to date and suggests that the folding mechanism may start with the hydrophobic collapse of the TR LBDs. Our results reveal that the stabilities of the LBDs of the TRalpha and TRbeta subtypes are affected to different degrees by the binding of the isoform selective ligand Triac and that ligand binding confers protection against thermal denaturation and unfolding in a subtype specific manner. Our simulations indicate two mechanisms by which the ligand stabilizes the LBD: (1) by enhancing the interactions between H8 and H11, and the interaction of the region between H1 and the Omega-loop with the core of the LBD, and (2) by shielding the hydrophobic H6 from hydration.