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The ability of the sexually transmitted parasite Trichomonas vaginalis to adhere to its human host is critical for establishing and maintaining an infection. Yet how parasites adhere to host cells is poorly understood., Trichomonas vaginalis is a highly prevalent, sexually transmitted parasite which adheres to mucosal epithelial cells to colonize the human urogenital tract. Despite adherence being crucial for this extracellular parasite to thrive within the host, relatively little is known about the mechanisms or key molecules involved in this process. Here, we have identified and characterized a T. vaginalis hypothetical protein, TVAG_157210 (TvAD1), as a surface protein that plays an integral role in parasite adherence to the host. Quantitative proteomics revealed TvAD1 to be ∼4-fold more abundant in parasites selected for increased adherence (MA parasites) than the isogenic parental (P) parasite line. De novo modeling suggested that TvAD1 binds N-acetylglucosamine (GlcNAc), a sugar comprising host glycosaminoglycans (GAGs). Adherence assays utilizing GAG-deficient cell lines determined that host GAGs, primarily heparan sulfate (HS), mediate adherence of MA parasites to host cells. TvAD1 knockout (KO) parasites, generated using CRISPR-Cas9, were found to be significantly reduced in host cell adherence, a phenotype that is rescued by overexpression of TvAD1 in KO parasites. In contrast, there was no significant difference in parasite adherence to GAG-deficient lines by KO parasites compared with wild-type, which is contrary to that observed for KO parasites overexpressing TvAD1. Isothermal titration calorimetric (ITC) analysis showed that TvAD1 binds to HS, indicating that TvAD1 mediates host cell adherence via HS interaction. In addition to characterizing the role of TvAD1 in parasite adherence, these studies reveal a role for host GAG molecules in T. vaginalis adherence.

Telomeres are structures at the ends of chromosomes that shorten during cell division and eventually signal an irreversible state of growth arrest known as cellular senescence. To delay this cellular aging, human T cells, which are critical in the immune control over infections and cancer, activate the enzyme telomerase, which binds and extends the telomeres. Several different extracts from the Astragalus membranaceus root have been documented to activate telomerase activity in human T cells. The objective of this research was to compare two extracts from Astragalus membranaceus, TA-65 and HTA, for their effects on both telomerase and proliferative activity of human CD4 and CD8 T cells. Our results demonstrate that, TA-65 increased telomerase activity significantly (1.3 to 3.3-fold relative to controls) in T cell cultures from six donors tested, whereas HTA only increased telomerase levels in two out of six donors. We also demonstrate that TA-65 activates telomerase by a MAPK- specific pathway. Finally, we determine that during a three-day culture period, only the T cells treated with the TA-65 extract showed a statistically significant increase in proliferative activity. Our results underscore the importance of comparing multiple telomerase activators within the same experiment, and of including functional assays in addition to measuring telomerase activity.

Acinetobacter baumannii is an important human pathogen due to its multi-drug resistance. In this study, the genome of an ST10 outbreak A. baumannii isolate LAC-4 was completely sequenced to better understand its epidemiology, antibiotic resistance genetic determinants and potential virulence factors. Compared with 20 other complete genomes of A. baumannii, LAC-4 genome harbors at least 12 copies of five distinct insertion sequences. It contains 12 and 14 copies of two novel IS elements, ISAba25 and ISAba26, respectively. Additionally, three novel composite transposons were identified: Tn6250, Tn6251 and Tn6252, two of which contain resistance genes. The antibiotic resistance genetic determinants on the LAC-4 genome correlate well with observed antimicrobial susceptibility patterns. Moreover, twelve genomic islands (GI) were identified in LAC-4 genome. Among them, the 33.4-kb GI12 contains a large number of genes which constitute the K (capsule) locus. LAC-4 harbors several unique putative virulence factor loci. Furthermore, LAC-4 and all 19 other outbreak isolates were found to harbor a heme oxygenase gene (hemO)-containing gene cluster. The sequencing of the first complete genome of an ST10 A. baumannii clinical strain should accelerate our understanding of the epidemiology, mechanisms of resistance and virulence of A. baumannii.

Objective: To investigate the relationship between alcohol intake and serum level of high-density lipoprotein (HDL) subfractions defined on the basis of their apolipoprotein A-I and A-II content (LpA-I and LpA-I:A-II). Design: Observational study. Setting: Institute of Internal Medicine and Medical Physiopathology, IRCCS Maggiore Hospital, University of Milan. Subjects: One hundred healthy males with a mean age of 42±11.1 y, selected among blood donors. Results: Both LpA-I and LpA-I:A-II were significantly higher in men drinking more than 30 g a day of alcohol than in non-drinkers (LpA-I: difference between means 6.5 mg/dL, 95% C.I. 1.14–11.9; LpA-I:A-II difference between means 11.5 mg/dL, 95% C.I. 0.52–22.5). The association of alcohol consumption with LpA-I and LpA-I:A-II levels was independent from age, body mass index, physical activity, serum triglycerides and diet composition. Conclusions: Alcohol consumption is associated with an increase of serum levels of both LpA-I and LpA-I:A-II particles and this may, at least in part, explain the reduced cardiovascular morbidity observed in subjects drinking moderate amounts of alcoholic beverages. Sponsorship: Supported by grants from Ricerca Corrente Ospedale Maggiore di Milano IRCCS, Milan Italy.

Trichomonas vaginalis (Tv) is an extracellular protozoan parasite that causes the most common non-viral sexually transmitted infection: trichomoniasis. While acute symptoms in women may include vaginitis, infections are often asymptomatic, but can persist and are associated with medical complications including increased HIV susceptibility, infertility, pre-term labor, and higher incidence of cervical cancer. Heightened inflammation resulting from Tv infection could account for these complications. Effective cellular immune responses to Tv have not been characterized, and re-infection is common, suggesting a dysfunctional adaptive immune response. Using primary human leukocyte components, we have established an in vitro co-culture system to assess the interaction between Tv and the cells of the human immune system. We determined that in vitro, Tv is able to lyse T-cells and B-cells, showing a preference for B-cells. We also found that Tv lysis of lymphocytes was mediated by contact-dependent and soluble factors. Tv lysis of monocytes is far less efficient, and almost entirely contact-dependent. Interestingly, a common symbiont of Tv, Mycoplasma hominis, did not affect cytolytic activity of the parasite, but had a major impact on cytokine responses. M. hominis enabled more diverse inflammatory cytokine secretion in response to Tv and, of the cytokines tested, Tv strains cleared of M. hominis induced only IL-8 secretion from monocytes. The quality of the adaptive immune response to Tv is therefore likely influenced by Tv symbionts, commensals, and concomitant infections, and may be further complicated by direct parasite lysis of effector immune cells., Author Summary The unicellular parasite Trichomonas vaginalis (Tv) causes the most common non-viral sexually transmitted infection worldwide, with approximately one quarter of a billion people infected annually. Tv infections are linked to pre-term and low-weight infant birth, increased susceptibility to and transmission of HIV infection, and increased aggressiveness of urogenital tract cancers. How the immune system responds to Tv, and how the parasite persists in the presence of the immune system, is not well understood. We show that Tv can kill human immune cells. We found that a clinical isolate of Tv is more efficient at killing immune cells than a laboratory-adapted strain, and that Tv preferentially targets B-cells. This killing activity is mediated by both contact-dependent and soluble factors. Killing immune cells could allow Tv to subvert or disable the immune system. Conversely, we found that cells of the immune system respond to Tv by secreting soluble inflammatory mediators called cytokines, mainly interleukin-8. However, these cells secrete greater amounts, and a broader profile of inflammatory cytokines when they encounter Tv harboring its symbiont bacterium, Mycoplasma hominis. We conclude that Tv may interact with immune cells in different ways, depending on the strain of Tv and the symbiont it harbors.