High Prevalence of SARS-CoV-2 Omicron Infection Despite High Seroprevalence, Sweden, 2022.

We performed 2 surveys during 2022 to estimate point prevalences of SARS-CoV-2 infection compared with overall seroprevalence in Sweden. Point prevalence was 1.4% in March and 1.5% in September. Estimated seroprevalence was >80%, including among unvaccinated children. Continued SARS-CoV-2 surveillance is necessary for detecting emerging, possibly more pathogenic variants.

Metabolic Perturbation Associated With COVID-19 Disease Severity and SARS-CoV-2 Replication.

Viruses hijack host metabolic pathways for their replicative advantage. In this study, using patient-derived multiomics data and in vitro infection assays, we aimed to understand the role of key metabolic pathways that can regulate severe acute respiratory syndrome coronavirus-2 reproduction and their association with disease severity. We used multiomics platforms (targeted and untargeted proteomics and untargeted metabolomics) on patient samples and cell-line models along with immune phenotyping of metabolite transporters in patient blood cells to understand viral-induced metabolic modulations. We also modulated key metabolic pathways that were identified using multiomics data to regulate the viral reproduction in vitro. Coronavirus disease 2019 disease severity was characterized by increased plasma glucose and mannose levels. Immune phenotyping identified altered expression patterns of carbohydrate transporter, glucose transporter 1, in CD8+ T cells, intermediate and nonclassical monocytes, and amino acid transporter, xCT, in classical, intermediate, and nonclassical monocytes. In in vitro lung epithelial cell (Calu-3) infection model, we found that glycolysis and glutaminolysis are essential for virus replication, and blocking these metabolic pathways caused significant reduction in virus production. Taken together, we therefore hypothesized that severe acute respiratory syndrome coronavirus-2 utilizes and rewires pathways governing central carbon metabolism leading to the efflux of toxic metabolites and associated with disease severity. Thus, the host metabolic perturbation could be an attractive strategy to limit the viral replication and disease severity.

Fecal Metabolome Signature in the HIV-1 Elite Control Phenotype: Enrichment of Dipeptides Acts as an HIV-1 Antagonist but a Prevotella Agonist.

HIV-1 elite controllers (EC) are a rare group among HIV-1-infected individuals who can naturally control viral replication for a prolonged period. Due to their heterogeneous nature, no universal mechanism could be attributed to the EC status; instead, several host and viral factors have been discussed as playing a role. In this study, we investigated the fecal metabolome and microbiome in a Swedish cohort of EC (n = 14), treatment-naive viremic progressors (VP; n = 16), and HIV-negative individuals (HC; n = 12). Fecal untargeted metabolomics was performed by four ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Molecular docking and biochemical microscale thermophoresis (MST) were used to describe the peptide-metabolite interactions. Single-cycle infectivity assays were performed in TZM-Bl cell lines using CCR5- and CXCR4-tropic HIV-1 strains. The microbiome analysis was performed using 16S rRNA sequencing. Th effects of metabolites on bacterial species viability were determined using several clinical isolates. We observed an enrichment of dipeptides in EC compared to VP and HC (adjusted P < 0.05). In silico analysis by molecular docking, in vitro biochemical assays, and ex vivo infection assays identified anti-HIV-1 properties for two dipeptides (WG and VQ) that could bind to the HIV-1 gp120, of which WG was more potent. The microbiome analysis identified enrichment of the genus Prevotella in EC, and these dipeptides supported bacterial growth of the genus Prevotella in vitro. The enrichments of the dipeptides and higher abundance of Prevotella have a distinct mechanism of elite control status in HIV-1 infection that influences host metabolism. IMPORTANCE HIV-1 elite controllers (EC) are a rare group among HIV-1-infected individuals who can naturally control viral replication for a prolonged period. Due to their heterogeneous nature, no universal mechanism could be attributed to the EC status; instead, several host and viral factors have been discussed as playing a role. In this study, we investigated the fecal metabolome and microbiome in a Swedish cohort of EC, treatment-naive viremic progressors (VP), and HIV-negative individuals (HC). We observed an enrichment of dipeptides in EC compared to the other two study groups. In silico and in vitro analyses identified anti-HIV-1 properties for two dipeptides that could bind to the HIV-1 gp120 and act as an HIV-1 antagonist. Furthermore, these dipeptides supported bacterial growth of the genus Prevotella in vitro that was enriched in EC, which influences host metabolism. Thus, increased levels of both dipeptides and Prevotella could provide beneficial effects for EC.

Utility of Proteomics in Emerging and Re-Emerging Infectious Diseases Caused by RNA Viruses.

Emerging and re-emerging infectious diseases due to RNA viruses cause major negative consequences for the quality of life, public health, and overall economic development. Most of the RNA viruses causing illnesses in humans are of zoonotic origin. Zoonotic viruses can directly be transferred from animals to humans through adaptation, followed by human-to-human transmission, such as in human immunodeficiency virus (HIV), severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and, more recently, SARS coronavirus 2 (SARS-CoV-2), or they can be transferred through insects or vectors, as in the case of Crimean-Congo hemorrhagic fever virus (CCHFV), Zika virus (ZIKV), and dengue virus (DENV). At the present, there are no vaccines or antiviral compounds against most of these viruses. Because proteins possess a vast array of functions in all known biological systems, proteomics-based strategies can provide important insights into the investigation of disease pathogenesis and the identification of promising antiviral drug targets during an epidemic or pandemic. Mass spectrometry technology has provided the capacity required for the precise identification and the sensitive and high-throughput analysis of proteins on a large scale and has contributed greatly to unravelling key protein-protein interactions, discovering signaling networks, and understanding disease mechanisms. In this Review, we present an account of quantitative proteomics and its application in some prominent recent examples of emerging and re-emerging RNA virus diseases like HIV-1, CCHFV, ZIKV, and DENV, with more detail with respect to coronaviruses (MERS-CoV and SARS-CoV) as well as the recent SARS-CoV-2 pandemic.

Immune Checkpoints as the Immune System Regulators and Potential Biomarkers in HIV-1 Infection.

Immune checkpoints are several co-stimulatory and inhibitory pathways that regulate T cell immune responses. Most of the discoveries about immune checkpoints were made in cancer research where inhibitory immune checkpoints cause immune exhaustion and down-regulate anti-tumor responses. In addition to cancer, immune checkpoints are exploited in chronic infectious diseases. In human immunodeficiency virus (HIV) infection, the immune checkpoint molecule called programmed cell death protein 1 (PD-1) has been determined as being a major regulatory factor for T cell exhaustion. Recent studies with antibodies blocking either PD-1 ligand 1 (PD-L1) or PD-1 show not only promising results in the enhancement of HIV-specific immune responses but even in reducing the latent HIV reservoir. Apart from the therapeutic target for a functional cure of HIV-1, immune checkpoint molecules might be used as biomarkers for monitoring disease progression and therapeutic response. In this review, we will summarize and discuss the inhibitory immune checkpoint molecules PD-1, cytotoxic T-lymphocyte-associated protein 4 (CTLA4), lymphocyte-activation gene 3 (LAG3), and T cell immunoglobulin and mucin-domain-containing-3 (TIM3) as well as the co-stimulatory molecules CD40L and CD70, including their role in immunity, with a particular focus on HIV infection, and being potential targets for a functional HIV cure.

Genome-scale metabolic models for natural and long-term drug-induced viral control in HIV infection.

Genome-scale metabolic models (GSMMs) can provide novel insights into metabolic reprogramming during disease progression and therapeutic interventions. We developed a context-specific system-level GSMM of people living with HIV (PLWH) using global RNA sequencing data from PBMCs with suppressive viremia either by natural (elite controllers, PLWHEC) or drug-induced (PLWHART) control. This GSMM was compared with HIV-negative controls (HC) to provide a comprehensive systems-level metabo-transcriptomic characterization. Transcriptomic analysis identified up-regulation of oxidative phosphorylation as a characteristic of PLWHART, differentiating them from PLWHEC with dysregulated complexes I, III, and IV. The flux balance analysis identified altered flux in several intermediates of glycolysis including pyruvate, α-ketoglutarate, and glutamate, among others, in PLWHART The in vitro pharmacological inhibition of OXPHOS complexes in a latent lymphocytic cell model (J-Lat 10.6) suggested a role for complex IV in latency reversal and immunosenescence. Furthermore, inhibition of complexes I/III/IV induced apoptosis, collectively indicating their contribution to reservoir dynamics.

Integrative proteo-transcriptomic and immunophenotyping signatures of HIV-1 elite control phenotype: A cross-talk between glycolysis and HIF signaling.

Natural control of HIV-1 is a characteristic of <1% of HIV-1-infected individuals, so called elite controllers (EC). In this study, we sought to identify signaling pathways associated with the EC phenotype using integrative proteo-transcriptomic analysis and immunophenotyping. We found HIF signaling and glycolysis as specific traits of the EC phenotype together with dysregulation of HIF target gene transcription. A higher proportion of HIF-1α and HIF-1ß in the nuclei of CD4+ and CD8+ T cells in the male EC were observed, indicating a potential increased activation of the HIF signaling pathway. Furthermore, intracellular glucose levels were elevated in EC even as the surface expression of the metabolite transporters Glut1 and MCT-1 were decreased on lymphocytes indicative of unique metabolic uptake and flux profile. Combined, our data show that glycolytic modulation and altered HIF signaling is a unique feature of the male EC phenotype that may contribute to natural control of HIV-1.

Peripheral blood CD4+CCR6+ compartment differentiates HIV-1 infected or seropositive elite controllers from long-term successfully treated individuals.

HIV-1 infection induces a chronic inflammatory environment not restored by suppressive antiretroviral therapy (ART). As of today, the effect of viral suppression and immune reconstitution in people living with HIV-1 (PLWH) has been well described but not completely understood. Herein, we show how PLWH who naturally control the virus (PLWHEC) have a reduced proportion of CD4+CCR6+ and CD8+CCR6+ cells compared to PLWH on suppressive ART (PLWHART) and HIV-1 negative controls (HC). Expression of CCR2 was reduced on both CD4+, CD8+ and classical monocytes in PLWHEC compared to PLWHART and HC. Longer suppressive therapy, measured in the same patients, decreased number of cells expressing CCR2 on all monocytic cell populations while expression on CD8+ T cells increased. Furthermore, the CD4+CCR6+/CCR6- cells exhibited a unique proteomic profile with a modulated energy metabolism in PLWHEC compared to PLWHART independent of CCR6 status. The CD4+CCR6+ cells also showed an enrichment in proteins involved in apoptosis and p53 signalling in PLWHEC compared to PLWHART, indicative of increased sensitivity towards cell death mechanisms. Collectively, this data shows how PLWHEC have a unique chemokine receptor profile that may aid in facilitating natural control of HIV-1 infection.

Multi-omics personalized network analyses highlight progressive disruption of central metabolism associated with COVID-19 severity.

The clinical outcome and disease severity in coronavirus disease 2019 (COVID-19) are heterogeneous, and the progression or fatality of the disease cannot be explained by a single factor like age or comorbidities. In this study, we used system-wide network-based system biology analysis using whole blood RNA sequencing, immunophenotyping by flow cytometry, plasma metabolomics, and single-cell-type metabolomics of monocytes to identify the potential determinants of COVID-19 severity at personalized and group levels. Digital cell quantification and immunophenotyping of the mononuclear phagocytes indicated a substantial role in coordinating the immune cells that mediate COVID-19 severity. Stratum-specific and personalized genome-scale metabolic modeling indicated monocarboxylate transporter family genes (e.g., SLC16A6), nucleoside transporter genes (e.g., SLC29A1), and metabolites such as α-ketoglutarate, succinate, malate, and butyrate could play a crucial role in COVID-19 severity. Metabolic perturbations targeting the central metabolic pathway (TCA cycle) can be an alternate treatment strategy in severe COVID-19.

Trans cohort metabolic reprogramming towards glutaminolysis in long-term successfully treated HIV-infection.

Despite successful combination antiretroviral therapy (cART), persistent low-grade immune activation together with inflammation and toxic antiretroviral drugs can lead to long-lasting metabolic flexibility and adaptation in people living with HIV (PLWH). Our study investigated alterations in the plasma metabolic profiles by comparing PLWH on long-term cART(>5 years) and matched HIV-negative controls (HC) in two cohorts from low- and middle-income countries (LMIC), Cameroon, and India, respectively, to understand the system-level dysregulation in HIV-infection. Using untargeted and targeted LC-MS/MS-based metabolic profiling and applying advanced system biology methods, an altered amino acid metabolism, more specifically to glutaminolysis in PLWH than HC were reported. A significantly lower level of neurosteroids was observed in both cohorts and could potentiate neurological impairments in PLWH. Further, modulation of cellular glutaminolysis promoted increased cell death and latency reversal in pre-monocytic HIV-1 latent cell model U1, which may be essential for the clearance of the inducible reservoir in HIV-integrated cells.

Distinct lipid profile, low-level inflammation, and increased antioxidant defense signature in HIV-1 elite control status.

HIV-1 elite controllers (EC) are a rare but heterogeneous group of HIV-1-infected individuals who can suppress viral replication in the absence of antiretroviral therapy. The mechanisms of how EC achieve undetectable viral loads remain unclear. This study aimed to investigate host plasma metabolomics and targeted plasma proteomics in a Swedish HIV-1 cohort including EC and treatment-naïve viremic progressors (VP) as well as HIV-negative individuals (HC) to get insights into EC phenotype. Metabolites belonging to antioxidant defense had higher levels in EC relative to VP, whereas inflammation markers were increased in VP compared with EC. Only four plasma proteins (CCL4, CCL7, CCL20, and NOS3) were increased in EC compared with HC, and CCL20/CCR6 axis can play an essential role in EC status. Our study suggests that low-level inflammation and oxidative stress at physiological levels could be important factors contributing to elite control phenotype.

Publisher Correction: In vitro replicative fitness of early Transmitted founder HIV-1 variants and sensitivity to Interferon alpha.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

In vitro replicative fitness of early Transmitted founder HIV-1 variants and sensitivity to Interferon alpha.

Type I interferons, particularly interferon-alpha (IFN-α), play a vital role in the host's anti-viral defenses by interfering with viral replication. However, the virus rapidly evolves to exploit the IFN-α response for its replication, spread, and pathogenic function. In this study, we attempted to determine IFN-α susceptibility and productivity of infectious transmitted/founder (TF) (n = 8) and non-transmitted (NT) viruses (n = 8) derived from HIV-1 infected infants. Independent experiments were carried out to determine IFN-α resistance, replication fitness, and viral productivity in CD4+ T cells over a short period. In vitro studies showed that TF viruses were resistant to IFN-α during the very near moment of transmission, but in the subsequent time points, they became susceptible to IFN-α. We did not observe much difference in replicative fitness of the TF viruses in cultures treated with and without IFN-α, but the difference was significant in the case of NT viruses obtained from the same individual. Despite increased susceptibility to IFN-α, NT viruses produced more viral particles than TF viruses. Similar results were also obtained in cultures treated with maraviroc (MVC). The study identified unique characteristics of TF viruses thus prompting further investigation into virus-host interaction occurring during the early stages of HIV infection.

Dysregulation in Akt/mTOR/HIF-1 signaling identified by proteo-transcriptomics of SARS-CoV-2 infected cells.

How severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections engage cellular host pathways and innate immunity in infected cells remains largely elusive. We performed an integrative proteo-transcriptomics analysis in SARS-CoV-2 infected Huh7 cells to map the cellular response to the invading virus over time. We identified four pathways, ErbB, HIF-1, mTOR and TNF signaling, among others that were markedly modulated during the course of the SARS-CoV-2 infection in vitro. Western blot validation of the downstream effector molecules of these pathways revealed a dose-dependent activation of Akt, mTOR, S6K1 and 4E-BP1 at 24 hours post infection (hpi). However, we found a significant inhibition of HIF-1α through 24hpi and 48hpi of the infection, suggesting a crosstalk between the SARS-CoV-2 and the Akt/mTOR/HIF-1 signaling pathways. Inhibition of the mTOR signaling pathway using Akt inhibitor MK-2206 showed a significant reduction in virus production. Further investigations are required to better understand the molecular sequelae in order to guide potential therapy in the management of severe coronavirus disease 2019 (COVID-19) patients.

HIV elite control is associated with reduced TRAILshort expression.

OBJECTIVE: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) dependent apoptosis has been implicated in CD4 T-cell death and immunologic control of HIV-1 infection. We have described a splice variant called TRAILshort, which is a dominant negative ligand that antagonizes TRAIL-induced cell death in the context of HIV-1 infection. HIV-1 elite controllers naturally control viral replication for largely unknown reasons. Since enhanced death of infected cells might be responsible, as might occur in situations of low (or inhibited) TRAILshort, we tested whether there was an association between elite controller status and reduced levels of TRAILshort expression. DESIGN: Cohort study comparing TRAILshort and full length TRAIL expression between HIV-1 elite controllers and viremic progressors from two independent populations. METHODS: TRAILshort and TRAIL gene expression in peripheral blood mononuclear cells (PBMCs) was determined by RNA-seq. TRAILshort and TRAIL protein expression in plasma was determined by antibody bead array and proximity extension assay respectively. RESULTS: HIV-1 elite controllers expressed less TRAILshort transcripts in PBMCs (P = 0.002) and less TRAILshort protein in plasma (P < 0.001) than viremic progressors. CONCLUSION: Reduced TRAILshort expression in PBMCs and plasma is associated with HIV-1 elite controller status.

Plasma Metabolic Signature and Abnormalities in HIV-Infected Individuals on Long-Term Successful Antiretroviral Therapy.

Targeted metabolomics studies reported metabolic abnormalities in both treated and untreated people living with human immunodeficiency virus (HIV) (PLHIV). The present study aimed to understand the plasma metabolomic changes and predicted the risk of accelerated aging in PLHIV on long-term suppressive antiretroviral therapy (ART) in a case-control study setting and its association with the plasma proteomics biomarkers of inflammation and neurological defects. Plasma samples were obtained from PLHIV on successful long-term ART for more than five years (n = 22) and matched HIV-negative healthy individuals (n = 22, HC herein). Untargeted metabolite profiling was carried out using ultra-high-performance liquid chromatography/mass spectrometry/mass spectrometry (UHPLC/MS/MS). Plasma proteomics profiling was performed using proximity extension assay targeting 184 plasma proteins. A total of 250 metabolites differed significantly (p < 0.05, q < 0.1) between PLHIV and HC. Plasma levels of several essential amino acids except for histidine, branched-chain amino acids, and aromatic amino acids (phenylalanine, tyrosine, tryptophan) were significantly lower in PLHIV compared to HC. Machine-learning prediction of metabolite changes indicated a higher risk of inflammatory and neurological diseases in PLHIV. Metabolic abnormalities were observed in amino-acid levels, energetics, and phospholipids and complex lipids, which may reflect known differences in lipoprotein levels in PLHIV that can resemble metabolic syndrome (MetS).

Systemic Inflammation and the Increased Risk of Inflamm-Aging and Age-Associated Diseases in People Living With HIV on Long Term Suppressive Antiretroviral Therapy.

The ART program in low- and middle-income countries (LMIC) like India, follows a public health approach with a standardized regimen for all people living with HIV (PLHIV). Based on the evidence from high-income countries (HIC), the risk of an enhanced, and accentuated onset of premature-aging or age-related diseases has been observed in PLHIV. However, very limited data is available on residual inflammation and immune activation in the populations who are on first-generation anti-HIV drugs like zidovudine and lamivudine that have more toxic side effects. Therefore, the aim of the present study was to evaluate the levels of systemic inflammation and understand the risk of age-associated diseases in PLHIV on long-term suppressive ART using a large number of biomarkers of inflammation and immune activation. Blood samples were obtained from therapy naïve PLHIV (Pre-ART, n = 43), PLHIV on ART for >5 years (ART, n = 53), and HIV-negative healthy controls (HIVNC, n = 41). Samples were analyzed for 92 markers of inflammation, sCD14, sCD163, and telomere length. Several statistical tests were performed to compare the groups under study. Multivariate linear regression was used to investigate the associations. Despite a median duration of 8 years of successful ART, sCD14 (p < 0.001) and sCD163 (p = 0.04) levels continued to be significantly elevated in ART group as compared to HIVNC. Eleven inflammatory markers, including 4E-BP1, ADA, CCL23, CD5, CD8A, CST5, MMP1, NT3, SLAMF1, TRAIL, and TRANCE, were found to be significantly different (p < 0.05) between the groups. Many of these markers are associated with age-related co-morbidities including cardiovascular disease, neurocognitive decline and some of these markers are being reported for the first time in the context of HIV-induced inflammation. Linear regression analysis showed a significant negative association between HIV-1-positivity and telomere length (p < 0.0001). In ART-group CXCL1 (p = 0.048) and TGF-α (p = 0.026) showed a significant association with the increased telomere length and IL-10RA was significantly associated with decreased telomere length (p = 0.042). This observation warrants further mechanistic studies to generate evidence to highlight the need for enhanced treatment monitoring and special interventions in HIV-infected individuals.

Plasma soluble factor following two decades prolonged suppressive antiretroviral therapy in HIV-1-positive males: A cross-sectional study.

Acute human immunodeficiency virus (HIV) infection is associated with a marked induction of several pathways that are linked to inflammation and CD4 T-cell depletion. Many of these processes do not fully resolve on short-term combination antiretroviral therapy (cART) (<5 years), despite complete and durable suppression of viremia. The effects of long-term (>15 years) successful antiretroviral therapy (ART) and the linkage between levels of biomarkers remain unclear. Therefore, the present study aims to assess the host plasma proteome in a well-defined clinical material from HIV-1-positive male patients on successful long-term ART (>15 years) and compared them with age-matched healthy controls and treatment-naïve male patients with viremia in a cross-sectional manner.Plasma samples were obtained from 3 categories of age-matched HIV-1-positive male patients on long-term successfully (ART, n = 10) with a median (Interquartile range, IQR) of 19 (17-20) years, treatment-naïve patients with viremia (VP, n = 14), and HIV-1-negative persons (HC, n = 11). Plasma proteome was analyzed using the proximity extension assay targeting 92 factors. Statistical analyses were performed with GraphPad Prism v7, R-packages, and Qlucore Omics Explorer v3.2. Functional enrichment analysis was performed by Kyoto Encyclopedia of Genes and Genomes (KEGG), and interactions of specific molecules were identified using Path Designer integrated into Ingenuity Pathway Analysis (IPA).Group wise comparison identified 53 soluble factors, which differed between the groups (P < .05). Cluster analysis identified 13 discrete soluble factors (CD8A, CRTAM, CXCL13, EGF, CD5, CD40, CXCL9, Gal-1, IL12RB1, KLRD1, PD-1, CASP-8 and TNFRSF9) between the studied groups (adjusted P < .001). The long-term successfully ART-treated individuals clustered and networked with the HC while VPs clustered separately. All of the proinflammatory cytokines and chemokines were normalized back to levels of healthy controls in long-term successfully ART-treated individuals, but not the levels of KLRD1 and PGDFB.sKLRD1 that is involved in the regulation of natural killer cell (NK) mediated cytotoxicity, failed to be restored to the level of HIV-negative individuals despite successful long-term ART. Additional analysis of NK cells along with T-cell subsets can provide insights into the long-term effects of ART on the immune system.

Transcriptomics and Targeted Proteomics Analysis to Gain Insights Into the Immune-control Mechanisms of HIV-1 Infected Elite Controllers.

A small subset of HIV-1 infected individuals, the "Elite Controllers" (EC), can control viral replication and restrain progression to immunodeficiency without antiretroviral therapy (ART). In this study, a cross-sectional transcriptomics and targeted proteomics analysis were performed in a well-defined Swedish cohort of untreated EC (n=19), treatment naïve patients with viremia (VP, n=32) and HIV-1-negative healthy controls (HC, n=23). The blood transcriptome identified 151 protein-coding genes that were differentially expressed (DE) in VP compared to EC. Genes like CXCR6 and SIGLEC1 were downregulated in EC compared to VP. A definite distinction in gene expression between males and females among all patient-groups were observed. The gene expression profile between female EC and the healthy females was similar but did differ between male EC and healthy males. At targeted proteomics analysis, 90% (29/32) of VPs clustered together while EC and HC clustered separately from VP. Among the soluble factors, 33 were distinctive to be statistically significant (False discovery rate=0.02). Cell surface receptor signaling pathway, programmed cell death, response to cytokine and cytokine-mediated signaling seem to synergistically play an essential role in HIV-1 control in EC.