Immunometabolic reprogramming during suppressive HIV-1 infection

Since the implementation of antiretroviral therapy (ART), infection with human immunodeficiency virus type-1 (HIV-1) has been transformed into a chronic lifelong condition. The main obstacle for a HIV-1 cure is the persistence of latently infected cells in viral reservoirs. The viral endurance can instigate detrimental changes on the function and activity of immune cells, creating a chronic inflammatory environment in people living with HIV-1 (PLWH) on successful long-term suppressive antiretroviral therapy (PLWHART). The continuous activation of immune cells may lead to an earlier onset of age-related diseases. Immunometabolism is an emerging field that studies how metabolic reprogramming has an impact on the activation, differentiation, and function of immune cells. Given that these underlying processes are likely to contribute to chronic inflammation in PLWH, the overall aim of this thesis was to evaluate how immunometabolism is reprogrammed during “controlled” HIV-1 infection, either by ART in PLWHART or in PLWH with natural control of infection, elite controllers (PLWHEC). In paper I, we integrated proteomic and transcriptomic data to investigate features distinct to the PLWHEC phenotype in a male cohort. We identified dysregulated hypoxia inducible factor (HIF) signalling and altered metabolism as unique characteristics of the male PLWHEC phenotype. As controlled HIV-1 infection still induce changes in the immune system we aimed to compare differences in the immune phenotype between PLWHEC and PLWHART and its relation to HIV-1 persistence in paper II. We identified a unique phenotype of decreased CCR6 expression on CD4+ and CD8+ T cells in PLWHEC compared to PLWHART and healthy controls (HC). Additionally, the CD4+CCR6+ cells exhibited a proteomic profile indicative of increased sensitivity towards cell death mechanisms in PLWHEC compared to PLWHART. A reduced proportion of integrated HIV-1 DNA in the reservoir of PLWHEC was found, although no difference in the amount of intact provirus. Continuing our evaluation of differences between PLWHEC and PLWHART we performed metabolo-transcriptomic analysis to understand and infer changes on a multisystem level in paper III. We detected a system level metabolic aberration mainly revolving around OXPHOS in PLWHART compared to PLWHEC. Using pharmacological modulation, we identified how this dysregulation of OXPHOS possibly affects HIV-1 reservoir dynamics and the immune senescence profile. Furthermore, to understand how HIV-1 chronicity affects long-lasting metabolic flexibility and adaptation we conducted plasma metabolomics to understand alterations during suppressive ART in a Swedish cohort in paper IV. We also aimed to characterize the cell populations that mainly contribute to changes in the metabolic environment. We detected aberrant energy metabolism in PLWHART, mainly revolving around the tricarboxylic acid cycle and amino acid synthesis. Cell-type specific evaluation showed that the main metabolic alterations occurred on monocytic cell populations, and that PLWHART exhibited dysregulated chemokine receptor expression of CCR2, CCR5, and CX3CR1 on myeloid cell lineages. In paper V, we wanted to evaluate if the altered metabolic environment was consistent on a global scale using two cohorts from low and middle-income countries (namely, Cameroon and India) using plasma metabolomics. We detected a dysregulation of amino acid metabolism and a switch towards glutaminolysis during long-term suppressive ART. In summary, the research covered in this thesis illuminates the importance of metabolic reprogramming during HIV-1 persistence in PLWH with controlled infection

Characterization of Inducible Transcription and Translation-Competent HIV-1 Using the RNAscope ISH Technology at a Single-Cell Resolution

Identifying the source and dynamics of persistent HIV-1 at single-cell resolution during cART is crucial for the design of strategies to eliminate the latent HIV-1 reservoir. An assay to measure latent HIV-1 that can distinguish inducible from defective proviruses with high precision is essential to evaluate the efficacy of HIV-1 cure efforts but is presently lacking. The primary aim of this study was therefore to identify transcription and translation competent latently infected cells through detection of biomolecules that are dependent on transcriptional activation of the provirus. We investigated the applicability of two commercially available assays; PrimeFlowTM RNA Assay (RNAflow) and RNAscope® ISH (RNAscope) for evaluation of the efficacy of latency reversal agents (LRAs) to reactivate the HIV-1 latent reservoir. The J-Lat cell model (clones 6.3, 9.3, and 10.6) and four LRAs was used to evaluate the sensitivity, specificity, and lower detection limit of the RNAflow and RNAscope assays for the detection and description of the translation-competent HIV-1 reservoir. We also checked for HIV-1 subtype specificity of the RNAscope assay using patient-derived subtype A1, B, C, and CRF01_AE recombinant plasmids following transfection in 293T cells and the applicability of the method in patient-derived peripheral blood mononuclear cells (PBMCs). The lower detection limit of RNAflow was 575 HIV-1 infected cells/million and 45 cells/million for RNAscope. The RNAscope probes, designed for HIV-1B, also detected other subtypes (A1, B, C, and CRF01_AE). RNAscope was applicable for the detection of HIV-1 in patient-derived PBMCs following LRA activation. In conclusion, our study showed that RNAscope can be used to quantify the number of directly observed individual cells expressing HIV-1 mRNA following LRA activation. Therefore, it can be a useful tool for characterization of translation-competent HIV-1 in latently infected cell at single-cell resolution in the fields of HIV-1 pathogenesis and viral persistence

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, = 43), PLHIV on ART for >5 years (ART, = 53), and HIV-negative healthy controls (HIVNC, = 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 ( < 0.001) and sCD163 ( = 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 ( < 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 ( < 0.0001). In ART-group CXCL1 ( = 0.048) and TGF-α ( = 0.026) showed a significant association with the increased telomere length and IL-10RA was significantly associated with decreased telomere length ( = 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

Multi-omics insights into host-viral response and pathogenesis in Crimean-Congo hemorrhagic fever viruses for novel therapeutic target.

The pathogenesis and host-viral interactions of the Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) are convoluted and not well evaluated. Application of the multi-omics system biology approaches, including biological network analysis in elucidating the complex host-viral response, interrogates the viral pathogenesis. The present study aimed to fingerprint the system-level alterations during acute CCHFV-infection and the cellular immune responses during productive CCHFV-replication in vitro. We used system-wide network-based system biology analysis of peripheral blood mononuclear cells (PBMCs) from a longitudinal cohort of CCHF patients during the acute phase of infection and after one year of recovery (convalescent phase) followed by untargeted quantitative proteomics analysis of the most permissive CCHFV-infected Huh7 and SW13 cells. In the RNAseq analysis of the PBMCs, comparing the acute and convalescent-phase, we observed system-level host's metabolic reprogramming towards central carbon and energy metabolism (CCEM) with distinct upregulation of oxidative phosphorylation (OXPHOS) during CCHFV-infection. Upon application of network-based system biology methods, negative coordination of the biological signaling systems like FOXO/Notch axis and Akt/mTOR/HIF-1 signaling with metabolic pathways during CCHFV-infection were observed. The temporal quantitative proteomics in Huh7 showed a dynamic change in the CCEM over time and concordant with the cross-sectional proteomics in SW13 cells. By blocking the two key CCEM pathways, glycolysis and glutaminolysis, viral replication was inhibited in vitro. Activation of key interferon stimulating genes during infection suggested the role of type I and II interferon-mediated antiviral mechanisms both at the system level and during progressive replication

Systems-level temporal immune-metabolic profile in Crimean-Congo hemorrhagic fever virus infection.

Crimean-Congo hemorrhagic fever (CCHF) caused by CCHF virus (CCHFV) is one of the epidemic-prone diseases prioritized by the World Health Organisation as public health emergency with an urgent need for accelerated research. The trajectory of host response against CCHFV is multifarious and remains unknown. Here, we reported the temporal spectrum of pathogenesis following the CCHFV infection using genome-wide blood transcriptomics analysis followed by advanced systems biology analysis, temporal immune-pathogenic alterations, and context-specific progressive and postinfection genome-scale metabolic models (GSMM) on samples collected during the acute (T0), early convalescent (T1), and convalescent-phase (T2). The interplay between the retinoic acid-inducible gene-I-like/nucleotide-binding oligomerization domain-like receptor and tumor necrosis factor signaling governed the trajectory of antiviral immune responses. The rearrangement of intracellular metabolic fluxes toward the amino acid metabolism and metabolic shift toward oxidative phosphorylation and fatty acid oxidation during acute CCHFV infection determine the pathogenicity. The upregulation of the tricarboxylic acid cycle during CCHFV infection, compared to the noninfected healthy control and between the severity groups, indicated an increased energy demand and cellular stress. The upregulation of glycolysis and pyruvate metabolism potentiated energy generation through alternative pathways associated with the severity of the infection. The downregulation of metabolic processes at the convalescent phase identified by blood cell transcriptomics and single-cell type proteomics of five immune cells (CD4+ and CD8+ T cells, CD14+ monocytes, B cells, and NK cells) potentially leads to metabolic rewiring through the recovery due to hyperactivity during the acute phase leading to post-viral fatigue syndrome

Chromatin maturation of the HIV-1 provirus in primary resting CD4+ T cells.

Human immunodeficiency virus type 1 (HIV-1) infection is a chronic condition, where viral DNA integrates into the genome. Latently infected cells form a persistent, heterogeneous reservoir that at any time can reactivate the integrated HIV-1. Here we confirmed that latently infected cells from HIV-1 positive study participants exhibited active HIV-1 transcription but without production of mature spliced mRNAs. To elucidate the mechanisms behind this we employed primary HIV-1 latency models to study latency establishment and maintenance. We characterized proviral transcription and chromatin development in cultures of resting primary CD4+ T-cells for four months after ex vivo HIV-1 infection. As heterochromatin (marked with H3K9me3 or H3K27me3) gradually stabilized, the provirus became less accessible with reduced activation potential. In a subset of infected cells, active marks (e.g. H3K27ac) and elongating RNAPII remained detectable at the latent provirus, despite prolonged proviral silencing. In many aspects, latent HIV-1 resembled an active enhancer in a subset of resting cells. The enhancer chromatin actively promoted latency and the enhancer-specific CBP/P300-inhibitor GNE049 was identified as a new latency reversal agent. The division of the latent reservoir according to distinct chromatin compositions with different reactivation potential enforces the notion that even though a relatively large set of cells contains the HIV-1 provirus, only a discrete subset is readily able to reactivate the provirus and spread the infection

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

Svensson Akusjärvi S, Krishnan S, Jütte B, et al. Peripheral blood CD4+CCR6+ compartment differentiates HIV-1 infected or seropositive elite controllers from long-term successfully treated individuals. Communications Biology. 2022;5(1): 357.**Abstract** 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 PLWHECcompared to PLWHARTand 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 PLWHECcompared to PLWHARTindependent of CCR6 status. The CD4+CCR6+cells also showed an enrichment in proteins involved in apoptosis and p53 signalling in PLWHECcompared to PLWHART, indicative of increased sensitivity towards cell death mechanisms. Collectively, this data shows how PLWHEChave a unique chemokine receptor profile that may aid in facilitating natural control of HIV-1 infection

Phenotypic Screening Identifies Synergistically Acting Natural Product Enhancing the Performance of Biomaterial Based Wound Healing

The potential of multifunctional wound heal biomaterial relies on the optimal content of therapeutic constituents as well as the desirable physical, chemical, and biological properties to accelerate the healing process. Formulating biomaterials such as amnion or collagen based scaffolds with natural products offer an affordable strategy to develop dressing material with high efficiency in healing wounds. Using image based phenotyping and quantification, we screened natural product derived bioactive compounds for modulators of types I and III collagen production from human foreskin derived fibroblast cells. The identified hit was then formulated with amnion to develop a biomaterial, and its biophysical properties, in vitro and in vivo effects were characterized. In addition, we performed functional profiling analyses by PCR array to understand the effect of individual components of these materials on various genes such as inflammatory mediators including chemokines and cytokines, growth factors, fibroblast stimulating markers for collagen secretion, matrix metalloproteinases, etc., associated with wound healing. FACS based cell cycle analyses were carried out to evaluate the potential of biomaterials for induction of proliferation of fibroblasts. Western blot analyses was done to examine the effect of biomaterial on collagen synthesis by cells and compared to cells grown in the presence of growth factors. This work demonstrated an uncomplicated way of identifying components that synergistically promote healing. Besides, we demonstrated that modulating local wound environment using biomaterials with bioactive compounds could enhance healing. This study finds that the developed biomaterials offer immense scope for healing wounds by means of their skin regenerative features such as anti-inflammatory, fibroblast stimulation for collagen secretion as well as inhibition of enzymes and markers impeding the healing, hydrodynamic properties complemented with other features including non-toxicity, biocompatibility, and safety

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, immune-phenotyping by flow cytometry, plasma metabolomics, and single cell-type metabolomics of the monocytes to identify the potential determinants of COVID-19 severity at the personalized and group level. Digital cell quantification and immune-phenotyping of the mononuclear phagocytes indicated a substantial role in coordinating the immune cells that mediate the 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