Project description:The HIV-1 surface glycoprotein Env binds target receptors to mediate fusion of the viral and host cell membranes during infection. Env is incorporated with very low density into virions, and in some cell types, regions within the long cytosolic C-terminal tail may mediate direct or indirect associations with Gag during virus assembly and budding. Here, the mutational landscape is determined across the transmembrane and proximal cytosolic domains of Env (001428 isolate from clade C) interacting with the MA domain of Gag at cellular membranes. No evidence is found in a derivative line of HEK293 cells for specific motifs that mediate Env/MA associations.
Project description:Comparison of expression levels of the genes on chromosome 22 in the peripheral blood mononuclear cells at various time points after stimulation with HIV-gag and env peptides
Project description:Sulfs represent a class of unconventional sulfatases, which differ from all other members of the sulfatase family by their structures, catalytic features and biological functions. Through their specific endosulfatase activity in extracellular milieu, Sulfs provide an original post-synthetic regulatory mechanism for heparan sulfate complex polysaccharides and have been involved in multiple physiopathological processes, including cancer. However, Sulfs remain poorly characterized enzymes, with major discrepancies regarding their in vivo functions. Here we show that human Sulf-2 (HSulf-2) features a unique polysaccharide post-translational modification. We identified a chondroitin/dermatan sulfate glycosaminoglycan (GAG) chain, attached to the enzyme substrate binding domain. We found that this GAG chain affects enzyme/substrate recognition and tunes HSulf-2 activity in vitro and in vivo using a mouse model of tumorigenesis and metastasis. In addition, we showed that mammalian hyaluronidase acted as a promoter of HSulf-2 activity by digesting its GAG chain. In conclusion, our results highlight HSulf-2 as a unique proteoglycan enzyme and its newly-identified GAG chain as a critical non-catalytic modulator of the enzyme activity. These findings contribute in clarifying the conflicting data on the activities of the Sulfs and introduce a new paradigm into the study of these enzymes.
Project description:In the context of host-pathogen interactions, gram-negative bacterial virulence factors, such as effectors, may be transferred from bacterial to eukaryotic host cytoplasm by multicomponent Type III protein secretion systems (T3SSs). Central to Salmonella enterica serovar Typhimurium (S. Typhimurium) pathogenesis is the secretion of over 40 effectors by two T3SSs encoded within pathogenicity islands SPI-1 and SPI-2. These effectors manipulate miscellaneous host cellular processes, such as cytoskeleton organization and immune signaling pathways, thereby permitting host colonization and bacterial dissemination. Recent research on effector biology provided mechanistic insights for some effectors. However, for many effectors, clearly defined roles and host target repertoires—further clarifying effector interconnectivity and virulence networks—are yet to be uncovered. Here we demonstrate the utility of the recently described viral-like particle trapping technology Virotrap as an effective approach to catalogue S. Typhimurium effector-host protein complexes (EH-PCs). Mass spectrometry-based Virotrap analysis of the novel E3 ubiquitin ligase SspH2 previously shown to be implicated in modulating actin dynamics and immune signaling, exposed known host interactors PFN1 and -2 and several putative novel, interconnected host targets. Network analysis revealed an actin(-binding) cluster among the significantly enriched hits for SspH2, consistent with the known localization of the S-palmitoylated effector with actin cytoskeleton components in the host. We show that Virotrap complements the current state-of-the-art toolkit to study protein complexes and represents a valuable means to screen for effector host targets in a high-throughput manner, thereby bridging the knowledge gap between effector-host interplay and pathogenesis.
Project description:All lentiviral vectors derived from HIV-1 have the major splice donor (SD1) in the 5’ leader region and splice acceptor 7 (SA7) within the env region. Splicing events decrease the amount of full-length RNA available for packaging into virions and could lead to packaging of genomes containing internal deletions. Because there are splice sites or splicing enhancer/silencer elements in both gag and env, we compared how deleting each region affected intracellular genomic RNA splicing in RNA isolated from transfected HEK293Tsa cells. Oxford Nanopore direct cDNA sequencing was used to characterize the splice variants because the long-read length allows full-length transcripts to be analyzed. We show that deleting 507 nt of env, including the SA7, decreased the number of splicing events per transcript and increased the proportion of unspliced genomic RNAs ~3-fold in the cell.
Project description:Study of the changes in the HEK293 proteome when growing without transfection, when transfected with an empty plasmid and when transfected with Gagcoding gene to produce Gag VLPs,
Project description:Attenuated poxviruses are safe and capable to express foreign antigens. Poxviruses are applied in veterinary vaccination and explored as candidate vaccines for humans. However, poxviruses express multiple genes encoding proteins that interfere with components of the innate and adaptive immune response. This manuscript describes two strategies aimed to improve the immunogenicity of the highly attenuated, host-range restricted poxvirus NYVAC: deletion of the viral gene encoding type-I interferon-binding protein and development of attenuated replication-competent NYVAC. We evaluated these newly generated NYVAC mutants, encoding HIV-1 env, gag, pol and nef, for their ability to stimulate HIV-specific CD8 T-cell responses from blood mononuclear cells of HIV-infected subjects. The new vectors were evaluated and compared to the parental NYVAC vector in dendritic cells (DCs), RNA expression arrays, HIV gag expression and direct and cross-presentation assays in vitro. Deletion of type-I interferon-binding protein enhanced expression of interferon and interferon-induced genes in DCs, and increased maturation of infected DCs. Restoration of replication competence induced activation of pathways involving antigen processing and presentation. Also, replication-competent NYVAC showed increased Gag expression in infected cells, permitting enhanced cross-presentation to HIV-specific CD8 T cells and proliferation of HIV-specific memory CD8 T-cells. The recombinant NYVAC combining both modifications induced interferon-induced genes and genes involved in antigen processing and presentation, as well as increased Gag expression. This combined replication-competent NYVAC is a promising candidate for the next generation of HIV vaccines. RNA expression obtained from DCs infected by NYVAC-C-dB19R and NYVAC-C-KC-dB19R compared to RNA expression obtained from DCs infected by NYVAC-C Supplementary file 'normalized_data_Human_V3_V2.txt' reports data for ILMN identifiers common to platforms HumanRef8V2 and HumanRef8V3.
Project description:Proteoglycans (PGs) are proteins with glycosaminoglycan (GAG) chains, such as chondroitin sulfate (CS) or heparan sulfate (HS), attached to serine residues. We have earlier shown that prohormones can carry CS, thus, constituting a novel class of PGs. The mapping of GAG modifications of proteins in endocrine cells may thus assist us in delineating possible roles of PGs in endocrine cellular physiology. With this aim, we applied a glycoproteomic approach to identify PGs, their GAG chains and their attachment sites in insulin-secreting cells. Glycopeptides carrying GAG chains were enriched from human pancreatic islets, rat (INS-1 832/13) and mouse (MIN6, NIT-1) insulinoma cell lines by ion exchange chromatography, depolymerized with GAG lyases, and analyzed by nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS). We identified CS modifications of chromogranin-A, islet amyloid polypeptide, secretogranin 1 and secretogranin 2, immunoglobulin superfamily member 10, and protein AMBP. Additionally, we identified two HS-modified prohormones (chromogranin-A and secretogranin-1), which was surprising, as prohormones are not typically regarded as HSPGs. For chromogranin-A, the glycosylation site carried either CS or HS, making it a so-called hybrid site. Additional HS sites were found on syndecan-1, syndecan-4, nerurexin-2, protein NDNF, and testican-1. These results demonstrate that several prohormones, and other constituents of the insulin-secreting cells are PGs. Cell-targeted mapping of the GAG glycoproteome forms an important basis for better understanding of endocrine cellular physiology, and the novel CS and HS sites presented here provide important knowledge for future studies.
Project description:Attenuated poxviruses are safe and capable to express foreign antigens. Poxviruses are applied in veterinary vaccination and explored as candidate vaccines for humans. However, poxviruses express multiple genes encoding proteins that interfere with components of the innate and adaptive immune response. This manuscript describes two strategies aimed to improve the immunogenicity of the highly attenuated, host-range restricted poxvirus NYVAC: deletion of the viral gene encoding type-I interferon-binding protein and development of attenuated replication-competent NYVAC. We evaluated these newly generated NYVAC mutants, encoding HIV-1 env, gag, pol and nef, for their ability to stimulate HIV-specific CD8 T-cell responses from blood mononuclear cells of HIV-infected subjects. The new vectors were evaluated and compared to the parental NYVAC vector in dendritic cells (DCs), RNA expression arrays, HIV gag expression and direct and cross-presentation assays in vitro. Deletion of type-I interferon-binding protein enhanced expression of interferon and interferon-induced genes in DCs, and increased maturation of infected DCs. Restoration of replication competence induced activation of pathways involving antigen processing and presentation. Also, replication-competent NYVAC showed increased Gag expression in infected cells, permitting enhanced cross-presentation to HIV-specific CD8 T cells and proliferation of HIV-specific memory CD8 T-cells. The recombinant NYVAC combining both modifications induced interferon-induced genes and genes involved in antigen processing and presentation, as well as increased Gag expression. This combined replication-competent NYVAC is a promising candidate for the next generation of HIV vaccines.
Project description:The primary objective of this study was to evaluate response to a SIV DNA-based vaccine that was adminstered via vivo electroporation (EP) in rhesus macaques to further understand the molecular correlates of protection against SIV. In this study, rhesus macaques were immunized with a DNA vaccine including individual plasmids encoding SIV gag, env, and pol alone, or in combination with a molecular adjuvant, plasmid DNA expressing the chemokine ligand 5 (RANTES), followed by EP. At eight month post-vaccination, animals were challenged with SIV. Standard immunological assays, flow-based activation analysis without ex vivo restimulation and high-throughput gene expression analysis were performed to determine the host response to each vaccine regimen.