Open Access

Differential cellular gene expression in duck trachea infected with a highly or low pathogenic H5N1 avian influenza viru

Impact of short term HAART initiated during the acute or chronic stage on SIV infection of the male genital tract

International audiencen.

Impact of Short-Term HAART Initiated during the Chronic Stage or Shortly Post-Exposure on SIV Infection of Male Genital Organs

International audienceBACKGROUND: The male genital tract is suspected to constitute a viral sanctuary as persistent HIV shedding is found in the semen of a subset of HIV-infected men receiving effective antiretroviral therapy (HAART). The origin of this persistent shedding is currently unknown. Phylogenetic studies indicated that HIV in semen from untreated men arises from local sources and/or passive diffusion from the blood. We previously demonstrated in human and macaque low levels and localized infection of several semen-producing organs by HIV/SIV. Using a macaque model, this study investigates the impact of short term HAART (2-4 weeks) initiated either during the asymptomatic chronic stage or 4 h post-intravenous inoculation of SIVmac251 on the infection of male genital organs. METHODOLOGY/PRINCIPAL FINDINGS: Short term HAART during the chronic stage decreased blood viral load. No major impact of HAART was observed on SIV DNA levels in male genital organs using a sensitive nested PCR assay. Using in situ hybridization, SIV RNA+ cells were detected in all male genital tract organs from untreated and treated animals with undetectable blood viral load following HAART. Infected CD68+ myeloid cells and CD3+ T lymphocytes were detected pre- and post-HAART. In contrast, short term HAART initiated 4 h post-SIV exposure led to a drastic decrease of the male genital tissues infection, although it failed to prevent systemic infection. In both cases, HAART tended to decrease the number of CD3+ T cells in the male organs. CONCLUSIONS: Our results indicate that the established infection of male genital organs is not greatly impacted by short term HAART, whereas the same treatment during pre-acute phase of the infection efficiently impairs viral dissemination to the male genital tract. Further investigations are now needed to determine whether infection of male genital organs is responsible for long term persistent HIV shedding in semen despite HAART

Elite control of HIV is associated with distinct functional and transcriptional signatures in lymphoid tissue CD8+ T cells

The functional properties of circulating CD8+ T cells have been associated with immune control of HIV. However, viral replication occurs predominantly in secondary lymphoid tissues, such as lymph nodes (LNs). We used an integrated single-cell approach to characterize effective HIV-specific CD8+ T cell responses in the LNs of elite controllers (ECs), defined as individuals who suppress viral replication in the absence of antiretroviral therapy (ART). Higher frequencies of total memory and follicle-homing HIV-specific CD8+ T cells were detected in the LNs of ECs compared with the LNs of chronic progressors (CPs) who were not receiving ART. Moreover, HIV-specific CD8+ T cells potently suppressed viral replication without demonstrable cytolytic activity in the LNs of ECs, which harbored substantially lower amounts of CD4+ T cell–associated HIV DNA and RNA compared with the LNs of CPs. Single-cell RNA sequencing analyses further revealed a distinct transcriptional signature among HIV-specific CD8+ T cells from the LNs of ECs, typified by the down-regulation of inhibitory receptors and cytolytic molecules and the up-regulation of multiple cytokines, predicted secreted factors, and components of the protein translation machinery. Collectively, these results provide a mechanistic framework to expedite the identification of novel antiviral factors, highlighting a potential role for the localized deployment of noncytolytic functions as a determinant of immune efficacy against HIV

Heterogeneous antiretroviral drug distribution and HIV/SHIV detection in the gut of three species

HIV replication within tissues may increase in response to a reduced exposure to antiretroviral drugs. Traditional approaches to measuring drug concentrations in tissues are unable to characterize a heterogeneous drug distribution. Here, we used mass spectrometry imaging (MSI) to visualize the distribution of six HIV antiretroviral drugs in gut tissue sections from three species (two strains of humanized mice, macaques, and humans). We measured drug concentrations in proximity to CD3+ T cells that are targeted by HIV, as well as expression of HIV or SHIV RNA and expression of the MDR1 drug efflux transporter in gut tissue from HIV-infected humanized mice, SHIV-infected macaques, and HIV-infected humans treated with combination antiretroviral drug therapy. Serial 10-μm sections of snap-frozen ileal and rectal tissue were analyzed by MSI for CD3+ T cells and MDR1 efflux transporter expression by immunofluorescence and immunohistochemistry, respectively. The tissue slices were analyzed for HIV/SHIV RNA expression by in situ hybridization and for antiretroviral drug concentrations by liquid chromatography-mass spectrometry. The gastrointestinal tissue distribution of the six drugs was heterogeneous. Fifty percent to 60% of CD3+ T cells did not colocalize with detectable drug concentrations in the gut tissue. In all three species, up to 90% of HIV/SHIV RNA was found to be expressed in gut tissue with no exposure to drug. These data suggest that there may be gut regions with little to no exposure to antiretroviral drugs, which may result in low-level HIV replication contributing to HIV persistence

CXCR5⁺ follicular cytotoxic T cells control viral infection in B cell follicles

During unresolved infections, some viruses escape immunological control and establish a persistant reservoir in certain cell types, such as human immunodeficiency virus (HIV), which persists in follicular helper T cells (TFH cells), and Epstein-Barr virus (EBV), which persists in B cells. Here we identified a specialized group of cytotoxic T cells (TC cells) that expressed the chemokine receptor CXCR5, selectively entered B cell follicles and eradicated infected TFH cells and B cells. The differentiation of these cells, which we have called 'follicular cytotoxic T cells' (TFC cells), required the transcription factors Bcl6, E2A and TCF-1 but was inhibited by the transcriptional regulators Blimp1, Id2 and Id3. Blimp1 and E2A directly regulated Cxcr5 expression and, together with Bcl6 and TCF-1, formed a transcriptional circuit that guided TFC cell development. The identification of TFC cells has far-reaching implications for the development of strategies to control infections that target B cells and TFH cells and to treat B cell–derived malignancies

Origine du VIH/SIV dans le sperme

Alors que le sperme représente le principal vecteur de dissémination du VIH, paradoxalement l'origine du virus dans ce fluide demeure mal connue. Les virus du sperme diffèrent en partie de ceux du sang, ce qui indique une production locale du VIH au sein du tractus génital mâle. De plus, la détection in situ d'éléments viraux au niveau des progéniteurs des spermatozoïdes (cellules germinales testiculaires) suggère une infection de ces cellules. Dans ce contexte, mes travaux de thèse se sont articulés autour de 2 axes: 1 L'étude de l'origine du VIH dans le sperme: Nous avons montré une infection productive des cellules immunitaires résidentes de la vésicule séminale humaine par le VIH-1 à la fois in vitro et in vivo. De plus, nous avons entrepris chez le macaque cynomolgus une comparaison phylogénique des souches de SIV amplifiées à partir des tissus du tractus génital mâle, du sperme et du sang, afin de déterminer les sources du VIH/SIV séminal. 2 L'étude des interactions entre les cellules germinales testiculaires humaines et le VIH: Nous avons montré que ces cellules expriment plusieurs récepteurs potentiels pour le VIH, et que le virus se fixe à ces cellules in vitro. Nos résultats préliminaires suggèrent la possibilité d'une entrée du virus dans les cellules germinales isolées. Sur la base de la littérature et de nos résultats, il apparaît clairement que les différents organes constituant le tractus génital masculin sont infectés par le VIH et donc susceptibles de contribuer à la charge virale séminale. De plus, nos travaux indiquent l'existence d'interactions entre les cellules germinales testiculaires et le VIH-1, ce qui ouvre de nombreuses perspectives d'études.Although semen represents the main vector for HIV dissemination worldwide, the origin of the virus in this body fluid remains unknown. Viral strains in semen are partly different from viral strains in the blood, indicating local viral production within the male genital tract. In addition, the in situ detection of viral elements within testicular germ cells suggests an infection of these spermatozoa progenitors. In this context, my thesis was articulated around 2 axes: 1 The study of the origin of HIV in semen: We demonstrated that the resident immune cells of the human seminal vesicles can support productive HIV infection in vitro and in vivo, and therefore have the potential to contribute virus to semen. Furthermore, we began a phylogenic comparison of SIV strains amplified from the organs of the male genital tract, semen and blood, to unravel the sources of seminal SIV/HIV. 2 Study of testicular germ cells and HIV interactions: We showed that testicular germ cells express potential receptors for HIV and that the virus can bind to these cells isolated from healthy men. Preliminary results suggest that testicular germ cells can support HIV entry. Based on the literature and on our results, it clearly appears that the male genital tract organs are infected by the HIV and thus susceptible to contribute to the seminal viral load. Furthermore, our results indicate the existence of interactions between human testicular germ cells and HIV-1, which pave the way for further investigations.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Next-generation in situ hybridization approaches to define and quantify HIV and SIV reservoirs in tissue microenvironments

Abstract The development of increasingly safe and effective antiretroviral treatments for human immunodeficiency virus (HIV) over the past several decades has led to vastly improved patient survival when treatment is available and affordable, an outcome that relies on uninterrupted adherence to combination antiretroviral therapy for life. Looking to the future, the discovery of an elusive ‘cure’ for HIV will necessitate highly sensitive methods for detecting, understanding, and eliminating viral reservoirs. Next-generation, in situ hybridization (ISH) approaches offer unique and complementary insights into viral reservoirs within their native tissue environments with a high degree of specificity and sensitivity. In this review, we will discuss how modern ISH techniques can be used, either alone or in conjunction with phenotypic characterization, to probe viral reservoir establishment and maintenance. In addition to focusing on how these techniques have already furthered our understanding of HIV reservoirs, we discuss potential avenues for how high-throughput, next-generation ISH may be applied. Finally, we will review how ISH could allow deeper phenotypic and contextual insights into HIV reservoir biology that should prove instrumental in moving the field closer to viral reservoir elimination needed for an ‘HIV cure’ to be realized

Insights into early extracellular matrix evolution: spongin short chain collagen-related proteins are homologous to basement membrane type IV collagens and form a novel family widely distributed in invertebrates.

International audienceCollagens are thought to represent one of the most important molecular innovations in the metazoan line. Basement membrane type IV collagen is present in all Eumetazoa and was found in Homoscleromorpha, a sponge group with a well-organized epithelium, which may represent the first stage of tissue differentiation during animal evolution. In contrast, spongin seems to be a demosponge-specific collagenous protein, which can totally substitute an inorganic skeleton, such as in the well-known bath sponge. In the freshwater sponge Ephydatia m?ri, we previously characterized a family of short-chain collagens that are likely to be main components of spongins. Using a combination of sequence- and structure-based methods, we present evidence of remote homology between the carboxyl-terminal noncollagenous NC1 domain of spongin short-chain collagens and type IV collagen. Unexpectedly, spongin short-chain collagen-related proteins were retrieved in nonsponge animals, suggesting that a family related to spongin constitutes an evolutionary sister to the type IV collagen family. Formation of the ancestral NC1 domain and divergence of the spongin short-chain collagen-related and type IV collagen families may have occurred before the parazoan-eumetazoan split, the earliest divergence among extant animal phyla. Molecular phylogenetics based on NC1 domain sequences suggest distinct evolutionary histories for spongin short-chain collagen-related and type IV collagen families that include spongin short-chain collagen-related gene loss in the ancestors of Ecdyzosoa and of vertebrates. The fact that a majority of invertebrates encodes spongin short-chain collagen-related proteins raises the important question to the possible function of its members. Considering the importance of collagens for animal structure and substratum attachment, both families may have played crucial roles in animal diversification