Project description:During sexual transmission of HIV-1 from male to female partners, the vagina is the initial site of contact with HIV infected semen. The mechanism of HIV traversing the CD4 negative multi-layered stratified squamous epithelial barrier of the vagina to infect sub-epithelial susceptible immune cells, is hitherto unknown. HIV gp120 binds to several host proteins on vaginal epithelial cells. To gain an insight into the physiologic changes that may occur in vaginal epithelial cells in response to interactions with HIV gp120, and obtain an understanding of the molecular mechanisms by which HIV breaches the vaginal epithelium, a global snap shot of gene expression profiles in the vaginal epithelial cell line Vk2/E6E7, treated with HIV gp120 was determined. The vaginal epithelial cell line Vk2/E6E7 was treated with HIV gp120 (83nM) for 24 hr, and Agilent one colour, microarrays were performed.
Project description:During sexual transmission of HIV-1 from male to female partners, the vagina is the initial site of contact with HIV infected semen. The mechanism of HIV traversing the CD4 negative multi-layered stratified squamous epithelial barrier of the vagina to infect sub-epithelial susceptible immune cells, is hitherto unknown. HIV gp120 binds to several host proteins on vaginal epithelial cells. To gain an insight into the physiologic changes that may occur in vaginal epithelial cells in response to interactions with HIV gp120, and obtain an understanding of the molecular mechanisms by which HIV breaches the vaginal epithelium, a global snap shot of gene expression profiles in the vaginal epithelial cell line Vk2/E6E7, treated with HIV gp120 was determined. The vaginal epithelial cell line Vk2/E6E7 was treated with HIV gp120 (83nM) for 24 hr, and Agilent one colour, microarrays were performed. Agilent one-color experiment,Organism: Human ,Agilent-Custom Whole Genome Human 8x60k designed by Genotypic Technology Pvt. Ltd. (AMADID: 027114), Labeling kit: Agilent Quick-Amp labeling Kit (p/n5190-0442)
Project description:The hormonal contraceptive medroxyprogesterone acetate (MPA) is associated with increased risk of human immunodeficiency virus (HIV), via incompletely understood mechanisms. Increased diversity in the vaginal microbiota modulates genital inflammation and is associated with increased HIV-1 acquisition. However, the effect of MPA on diversity of the vaginal microbiota is relatively unknown. In a cohort of female Kenyan sex workers, negative for sexually transmitted infections (STIs), with Nugent scores <7 (N=58 of 370 screened), MPA correlated with significantly increased diversity of the vaginal microbiota as assessed by 16S rRNA gene sequencing. MPA was also significantly associated with decreased levels of estrogen in the plasma, and low vaginal glycogen and α-amylase, factors implicated in vaginal colonization by lactobacilli, bacteria that are believed to protect against STIs. In a humanized mouse model, MPA treatment was associated with low serum estrogen, low glycogen and enhanced HIV-1 susceptibility. The mechanism by which the MPA mediated changes in the vaginal microbiota may contribute to HIV-1 susceptibility in humans appears to be independent of inflammatory cytokines and/or activated T cells. Altogether, these results suggest MPA-induced hypo-estrogenism may alter key metabolic components that are necessary for vaginal colonization by certain bacterial species including lactobacilli, and allow for greater bacterial diversity in the vaginal microbiota.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:The anti-HIV humoral immune response following acute infection is delayed and ineffective. HIV envelope protein gp120 binds to and signals through α4β7 on T cells. We show that gp120 also binds and signals through α4β7 on B cells, resulting in an abortive proliferative response. In primary B cells, gp120 signaling through α4β7 resulted in increased expression of TGF-β1 and the B cell inhibitory receptor FcRL4. Co-culture of B cells with HIV-infected autologous CD4+ T cells also resulted in increased B cell FcRL4 expression. These findings indicate that, in addition to inducing chronic immune activation, viral proteins can contribute directly to HIV-associated B cell dysfunction, thus providing a mechanism whereby the virus subverts the early HIV-specific humoral immune response. Forty-two samples in two batches were run with different treatments and different time points.
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
Project description:The anti-HIV humoral immune response following acute infection is delayed and ineffective. HIV envelope protein gp120 binds to and signals through α4β7 on T cells. We show that gp120 also binds and signals through α4β7 on B cells, resulting in an abortive proliferative response. In primary B cells, gp120 signaling through α4β7 resulted in increased expression of TGF-β1 and the B cell inhibitory receptor FcRL4. Co-culture of B cells with HIV-infected autologous CD4+ T cells also resulted in increased B cell FcRL4 expression. These findings indicate that, in addition to inducing chronic immune activation, viral proteins can contribute directly to HIV-associated B cell dysfunction, thus providing a mechanism whereby the virus subverts the early HIV-specific humoral immune response.
Project description:PurposeWe investigated the evidence of recent positive selection in the human phototransduction system at single nucleotide polymorphism (SNP) and gene level.MethodsSNP genotyping data from the International HapMap Project for European, Eastern Asian, and African populations was used to discover differences in haplotype length and allele frequency between these populations. Numeric selection metrics were computed for each SNP and aggregated into gene-level metrics to measure evidence of recent positive selection. The level of recent positive selection in phototransduction genes was evaluated and compared to a set of genes shown previously to be under recent selection, and a set of highly conserved genes as positive and negative controls, respectively.ResultsSix of 20 phototransduction genes evaluated had gene-level selection metrics above the 90th percentile: RGS9, GNB1, RHO, PDE6G, GNAT1, and SLC24A1. The selection signal across these genes was found to be of similar magnitude to the positive control genes and much greater than the negative control genes.ConclusionsThere is evidence for selective pressure in the genes involved in retinal phototransduction, and traces of this selective pressure can be demonstrated using SNP-level and gene-level metrics of allelic variation. We hypothesize that the selective pressure on these genes was related to their role in low light vision and retinal adaptation to ambient light changes. Uncovering the underlying genetics of evolutionary adaptations in phototransduction not only allows greater understanding of vision and visual diseases, but also the development of patient-specific diagnostic and intervention strategies.