Monica Miranda-Saksena

The genomic mechanisms underlying natural and effective control of viremia in HIV+ long-term non-progressors (LTNP) and elite controllers (ECs) remain obscured and poorly understood. We performed genome-wide transcriptomic expression analysis (Bead-Studio; 25,000 genes) on peripheral blood mononuclear cells from nine therapy-naïve LTNPs compared with 15 newly diagnosed HIV+ patients before and after > one year of control of viremia by HAART. Only significantly differentially expressed (DE) genes with p-value <0.01 and FDR (false discovery rate (FDR) of <1% were considered for further analysis. Pathway analysis was performed using MetaCoreTM to derive the functional annotations. Functionally significant genes were validated using quantitative real-time PCR, flow cytometry, and confocal and deltavision microscopy. Although LTNP had naturally controlled viremia (low to undetectable), gene expression levels in these LTNP were distinct from those in HIV+ patients with viremia controlled by HAART (below detection), highlighting the critical role and uniqueness of enriched pathways in the natural control of viremia in the LTNPs and ECs. Thrombospondin (THBS1) (R2 = 0.942) was identified as a POTENTIAL biomarker in our study, discriminating between viremic patients and LTNPs at the genomic (R2 = 0.942, p = 2.654e-08) and proteomic (p = 0.003761) levels. The expression levels of THBS1 were correlated with plasma viremia (R² = 0.81557; p = 0.0003761). Our results suggest a significant distinction between immune pathways in patients with therapy-mediated control of HIV replication compared to those with natural control of viremia in LTNPs, as identified by enriched genomic expression in immune activation, cytoskeletal remodeling, apoptosis, and T-cell signaling pathways. Thrombospondin plays an essential role in apoptosis; therefore, the downregulation of this marker in viremic patients MAY OFFER POTENTIAL AS A BIOMARKER for characterizing pathways of immunological control in untreated LTNP, in addition to predicting optimal treatment response in newly diagnosed HIV+ patients.

Herpes simplex virus-1 (HSV-1) is a human trophic virus capable of establishing lifelong latent infections in the neurons of the peripheral nervous system of human hosts. HSV-1 infects the host via the mucosa and skin where it replicates in epithelial cells [ 1]. Following this initial infection, the virus then enters and infects the sensory nerves of the dorsal root ganglia (DRG) or trigeminal ganglia neurons innervating the site of infection. The virus is then transported to the neuronal cell body where the viral genome is deposited in the nucleus, thereby establishing a lifelong latent infection. Viral reactivation leads to virus replication in the neuronal cell body and virus transport along nerves to the nerve terminals for subsequent spread into the skin or mucosa, resulting in either recurrent disease or asymptomatic virus shedding [ 1]. The aim of our study is to define how HSV-1 exits sensory nerves to spread to the skin during recurrent herpes. We used primary DRG neurons grown in a compartmentalized neuronal culture system that physically and fluidically separates axons from their neuronal cell bodies into two compartments. This system allows HSV-1 infection of neuronal cell bodies in one compartment and the separate treatment of axons in the second compartment [ 2]. Confocal microscopy was used to visualize viral and cellular proteins along axons, whereas electron microscopy of axons sectioned in their growth plane was used to visualize viral particles along axons and axonal growth cones located at the axon terminals [ 3]. Using this compartmentalized neuronal culture system, we showed that an intact actin cytoskeleton is required for final release of HSV-1 from axons and that myosin V is as a key molecular motor involved in this process [ 4].

Herpes simplex virus-1 (HSV-1) has evolved mechanisms to evade the host immune system and limit the antiviral effects induced by interferon (IFN) produced by local epithelial and immune cells. In this study, we determined the effects of type I, II, and III IFNs on HSV-1 release from sensory axons. Using compartmentalized microfluidic devices separating axons from the neuronal cell bodies, we showed that treating axons with type I (IFNα and IFNβ), type II (IFNγ), and type III (IFNλ) IFNs inhibited the release of HSV-1 from axons, without altering the anterograde axonal transport of viral components. Furthermore, we showed that only type II IFN induced a cell-wide response following axonal treatment, with phosphorylated STAT1 and STAT3 present along axons and in the neuronal cell body, whereas type I and III IFNs only induced a local STAT1 and STAT3 response in axons. We also showed that HSV-1 infection alone, in the absence of exogenous IFN, activated STAT1 and STAT3 in both neuronal cell bodies and along axons. However, HSV-1 infection restricted the translocation of pSTAT1 and pSTAT3 to the nucleus even in the presence of IFNs, suggesting viral evasion mechanisms are involved in limiting the IFN response in the neuronal cell body. Overall, our study indicates a key and greater antiviral role of IFNs in inhibiting HSV-1 release from axon termini than in the ganglia during recurrent infections and identifies a novel intervention site, the neuro-epidermal junction, for the development of new immunotherapies. IMPORTANCE: Herpes simplex virus-1 (HSV-1) is a human pathogen known to cause cold sores and genital herpes. HSV-1 establishes lifelong infections in our sensory neurons, with no cure or vaccine available. HSV-1 can reactivate sporadically and travel back along sensory nerves, where it can form lesions in the oral and genital mucosa, eye, and skin, or be shed asymptomatically. New treatment options are needed as resistance is emerging to current antiviral therapies. Here, we show that interferons (IFNs) are capable of blocking virus release from nerve endings, potentially stopping HSV-1 transmission into the skin. Furthermore, we show that IFNγ has the potential to have widespread antiviral effects in the neuron and may have additional effects on HSV-1 reactivation. Together, this study identifies new targets for the development of immunotherapies to stop the spread of HSV-1 from the nerves into the skin.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in the human host can lead to various clinical manifestations, from symptomless carriers to mild to moderate to severe/critical illness. Therefore, the clinical classification of SARS-CoV-2 disease, based on severity, is a reliable way to predict disease states in SARS-CoV-2 infection. Recent studies on genomics, transcriptomics, epigenomics, and immunogenomics, along with spatial analysis of immune cells have delineated and defined the categorization of these disease groups using these high throughout technologies. These technologies hold the promise of providing not only a detailed but a holistic view of SARS-CoV-2-led pathogenesis. The main genomic, cellular, and immunologic features of each disease category, and what separates them spatially and molecularly are discussed in this brief review to provide a foundational spatial understanding of SARS-CoV-2 immunopathogenesis.

Herpes simplex virus (HSV) infections are a worldwide health problem in need of new effective treatments. Of particular interest is the identification of antiviral agents that act via different mechanisms compared to current drugs, as these could interact synergistically with first-line antiherpetic agents to accelerate the resolution of HSV-1-associated lesions. For this study, we applied a structure-based molecular docking approach targeting the nectin-1 and herpesvirus entry mediator (HVEM) binding interfaces of the viral glycoprotein D (gD). More than 527,000 natural compounds were virtually screened using Autodock Vina and then filtered for favorable ADMET profiles. Eight top hits were evaluated experimentally in African green monkey kidney cell line (VERO) cells, which yielded two compounds with potential antiherpetic activity. One active compound (1-(1-benzofuran-2-yl)-2-[(5Z)-2H,6H,7H,8H-[1,3] dioxolo[4,5-g]isoquinoline-5-ylidene]ethenone) showed weak but significant antiviral activity. Although less potent than antiherpetic agents, such as acyclovir, it acted at the viral inactivation stage in a dose-dependent manner, suggesting a novel mode of action. These results highlight the feasibility of in silico approaches for identifying new antiviral compounds, which may be further optimized by medicinal chemistry approaches.

Herpes simplex virus type 1 (HSV-1) has evolved mechanisms to exploit the host cytoskeleton during entry, replication and exit from cells. In this study, we determined the role of actin and the molecular motor proteins, myosin II and myosin V, in the transport and release of HSV-1 from axon termini, or growth cones. Using compartmentalized neuronal devices, we showed that inhibition of actin polymerization, but not actin branching, significantly reduced the release of HSV-1 from axons. Furthermore, we showed that inhibition of myosin V, but not myosin II, also significantly reduced the release of HSV-1 from axons. Using confocal and electron microscopy, we determined that viral components are transported along axons to growth cones, despite actin or myosin inhibition. Overall, our study supports the role of actin in virus release from axonal growth cones and suggests myosin V as a likely candidate involved in this process.

As the severe acute respiratory syndrome coronavirus (SARS-CoV)-2 is a new virus, the current knowledge on the immunopathogenesis of this newly emerged SARS-CoV-2 is beginning to unravel with intensive ongoing global research efforts. Although a plethora of new studies have been published in a short space of time describing how the virus causes disease and incurs insults on the host immune system and the underlying immunopathogenic mechanisms remain to be elucidated. Thus, the discussion in this review is based on the most current knowledge on the immunopathogenesis of SARS-CoV-2 that has emerged in the past 12 months. The main objective is to shed light on the most current concepts in immunopathological aspects of the lung, bloodstream, and brain caused by the SARS-CoV-2, which has led to the current pandemic resulting in > 100 million infections and > 2 million deaths, and ongoing.

Skin mononuclear phagocytes (MNPs) provide the first interactions of invading viruses with the immune system. In addition to Langerhans cells (LCs), we recently described a second epidermal MNP population, Epi-cDC2s, in human anogenital epidermis that is closely related to dermal conventional dendritic cells type 2 (cDC2) and can be preferentially infected by HIV. Here we show that in epidermal explants topically infected with herpes simplex virus (HSV-1), both LCs and Epi-cDC2s interact with HSV-1 particles and infected keratinocytes. Isolated Epi-cDC2s support higher levels of infection than LCs in vitro, inhibited by acyclovir, but both MNP subtypes express similar levels of the HSV entry receptors nectin-1 and HVEM, and show similar levels of initial uptake. Using inhibitors of endosomal acidification, actin and cholesterol, we found that HSV-1 utilises different entry pathways in each cell type. HSV-1 predominantly infects LCs, and monocyte-derived MNPs, via a pH-dependent pathway. In contrast, Epi-cDC2s are mainly infected via a pH-independent pathway which may contribute to the enhanced infection of Epi-cDC2s. Both cells underwent apoptosis suggesting that Epi-cDC2s may follow the same dermal migration and uptake by dermal MNPs that we have previously shown for LCs. Thus, we hypothesize that the uptake of HSV and infection of Epi-cDC2s will stimulate immune responses via a different pathway to LCs, which in future may help guide HSV vaccine development and adjuvant targeting.

HSV-1 envelope glycoprotein E (gE) is important for viral egress and cell-to-cell spread but the host protein(s) involved in these functions have yet to be determined. We aimed to investigate a role for the Arp2/3 complex and actin regulation in viral egress based on the identification of a WAVE Regulatory Complex (WRC) Interacting Receptor Sequence (WIRS) in the cytoplasmic tail (CT) of gE. A WIRS-dependent interaction between the gE(CT) and subunits of the WRC was demonstrated by GST-pulldown assay and a role for the Arp2/3 complex in cell-to-cell spread was also observed by plaque assay. Subsequent study of a recombinant HSV-1 gE WIRS-mutant found no significant changes to viral production and release based on growth kinetics studies, or changes to plaque and comet size in various cell types, suggesting no function for the motif in cell-to-cell spread. GFP-Trap pulldown and proximity ligation assays were unable to confirm a WIRS-dependent interaction between gE and the WRC in human cell lines though the WIRS-independent interaction observed in situ warrants further study. Confocal microscopy of infected cells of neuronal origin identified no impairment of gE WIRS-mutant HSV-1 anterograde transport along axons. We propose that the identified gE WIRS motif does not function directly in recruitment of the WRC in human cells, in cell-to-cell spread of virus or in anterograde transport along axons. Further studies are needed to understand how HSV-1 manipulates and traverses the actin cytoskeleton and how gE may contribute to these processes in a WIRS-independent manner.