Serotonin reduction in post-acute sequelae of viral infection.

Post-acute sequelae of COVID-19 (PASC, "Long COVID") pose a significant global health challenge. The pathophysiology is unknown, and no effective treatments have been found to date. Several hypotheses have been formulated to explain the etiology of PASC, including viral persistence, chronic inflammation, hypercoagulability, and autonomic dysfunction. Here, we propose a mechanism that links all four hypotheses in a single pathway and provides actionable insights for therapeutic interventions. We find that PASC are associated with serotonin reduction. Viral infection and type I interferon-driven inflammation reduce serotonin through three mechanisms: diminished intestinal absorption of the serotonin precursor tryptophan; platelet hyperactivation and thrombocytopenia, which impacts serotonin storage; and enhanced MAO-mediated serotonin turnover. Peripheral serotonin reduction, in turn, impedes the activity of the vagus nerve and thereby impairs hippocampal responses and memory. These findings provide a possible explanation for neurocognitive symptoms associated with viral persistence in Long COVID, which may extend to other post-viral syndromes.

Multi-omics approach to socioeconomic disparity in metabolic syndrome reveals roles of diet and microbiome.

The epidemy of metabolic syndrome (MetS) is typically preceded by adoption of a "risky" lifestyle (e.g., dietary habit) among populations. Evidence shows that those with low socioeconomic status (SES) are at an increased risk for MetS. To investigate this, we recruited 123 obese subjects (body mass index [BMI] ≥ 30) from Chicago. Multi-omic data were collected to interrogate fecal microbiota, systemic markers of inflammation and immune activation, plasma metabolites, and plasma glycans. Intestinal permeability was measured using the sugar permeability testing. Our results suggest a heterogenous metabolic dysregulation among obese populations who are at risk of MetS. Systemic inflammation, linked to poor diet, intestinal microbiome dysbiosis, and gut barrier dysfunction may explain the development of MetS in these individuals. Our analysis revealed 37 key features associated with increased numbers of MetS features. These features were used to construct a composite metabolic-inflammatory (MI) score that was able to predict progression of MetS among at-risk individuals. The MI score was correlated with several markers of poor diet quality as well as lower levels of gut microbial diversity and abnormalities in several species of bacteria. This study reveals novel targets to reduce the burden of MetS and suggests access to healthy food options as a practical intervention.

Viral and Host Biomarkers of HIV Remission Post Treatment Interruption.

PURPOSE OF REVIEW: HIV rebound/remission after antiretroviral therapy (ART) interruption is likely influenced by (a) the size of the inducible replication-competent HIV reservoir and (b) factors in the host environment that influence immunological pressures on this reservoir. Identifying viral and/or host biomarkers of HIV rebound after ART cessation may improve the safety of treatment interruptions and our understanding of how the viral-host interplay results in post-treatment control. Here we review the predictive and functional significance of recently suggested viral and host biomarkers of time to viral rebound and post-treatment control following ART interruption. RECENT FINDINGS: There are currently no validated viral or host biomarkers of viral rebound; however, several biomarkers have been recently suggested. A combination of viral and host factors will likely be needed to predict viral rebound and to better understand the mechanisms contributing to post-treatment control of HIV, critical steps to developing a cure for HIV infection.

Immunogenicity of personalized dendritic-cell therapy in HIV-1 infected individuals under suppressive antiretroviral treatment: interim analysis from a phase II clinical trial.

BACKGROUND: We developed a personalized Monocyte-Derived Dendritic-cell Therapy (MDDCT) for HIV-infected individuals on suppressive antiretroviral treatment and evaluated HIV-specific T-cell responses. METHODS: PBMCs were obtained from 10 HIV+ individuals enrolled in trial NCT02961829. Monocytes were differentiated into DCs using IFN-α and GM-CSF. After sequencing each patient's HIV-1 Gag and determining HLA profiles, autologous Gag peptides were selected based on the predicted individual immunogenicity and used to pulse MDDCs. Three doses of the MDDCT were administered every 15 days. To assess immunogenicity, patients' cells were stimulated in vitro with autologous peptides, and intracellular IL-2, TNF, and interferon-gamma (IFN-γ) production were measured in CD4+ and CD8+ T-cells. RESULTS: The protocol of ex-vivo treatment with IFN-α and GM-CSF was able to induce maturation of MDDCs, as well as to preserve their viability for reinfusion. MDDCT administration was associated with increased expression of IL-2 in CD4+ and CD8+ T-cells at 15 and/or 30 days after the first MDDCT administration. Moreover, intracellular TNF and IFN-γ expression was significantly increased in CD4+ T-cells. The number of candidates that increased in vitro the cytokine levels in CD4+ and CD8+ T cells upon stimulation with Gag peptides from baseline to day 15 and from baseline to day 30 and day 120 after MDDCT was significant as compared to Gag unstimulated response. This was accompanied by an increasing trend in the frequency of polyfunctional T-cells over time, which was visible when considering both cells expressing two and three out of the three cytokines examined. CONCLUSIONS: MDDC had a mature profile, and this MDDCT promoted in-vitro T-cell immune responses in HIV-infected patients undergoing long-term suppressive antiretroviral treatment. Trial registration NCT02961829: (Multi Interventional Study Exploring HIV-1 Residual Replication: a Step Towards HIV-1 Eradication and Sterilizing Cure, https://www.clinicaltrials.gov/ct2/show/NCT02961829 , posted November 11th, 2016).

The African natural product knipholone anthrone and its analogue anthralin (dithranol) enhance HIV-1 latency reversal.

A sterilizing or functional cure for HIV is currently precluded by resting CD4+ T cells that harbor latent but replication-competent provirus. The "shock-and-kill" pharmacological ap-proach aims to reactivate provirus expression in the presence of antiretroviral therapy and target virus-expressing cells for elimination. However, no latency reversal agent (LRA) to date effectively clears viral reservoirs in humans, suggesting a need for new LRAs and LRA combinations. Here, we screened 216 compounds from the pan-African Natural Product Library and identified knipholone anthrone (KA) and its basic building block anthralin (dithranol) as novel LRAs that reverse viral latency at low micromolar concentrations in multiple cell lines. Neither agent's activity depends on protein kinase C; nor do they inhibit class I/II histone deacetylases. However, they are differentially modulated by oxidative stress and metal ions and induce distinct patterns of global gene expression from established LRAs. When applied in combination, both KA and anthralin synergize with LRAs representing multiple functional classes. Finally, KA induces both HIV RNA and protein in primary cells from HIV-infected donors. Taken together, we describe two novel LRAs that enhance the activities of multiple "shock-and-kill" agents, which in turn may inform ongoing LRA combination therapy efforts.

Breaking the Glyco-Code of HIV Persistence and Immunopathogenesis.

PURPOSE OF REVIEW: Glycoimmunology is an emerging field focused on understanding how immune responses are mediated by glycans (carbohydrates) and their interaction with glycan-binding proteins called lectins. How glycans influence immunological functions is increasingly well understood. In a parallel way, in the HIV field, it is increasingly understood how the host immune system controls HIV persistence and immunopathogenesis. However, what has mostly been overlooked, despite its potential for therapeutic applications, is the role that the host glycosylation machinery plays in modulating the persistence and immunopathogenesis of HIV. Here, we will survey four areas in which the links between glycan-lectin interactions and immunology and between immunology and HIV are well described. For each area, we will describe these links and then delineate the opportunities for the HIV field in investigating potential interactions between glycoimmunology and HIV persistence/immunopathogenesis. RECENT FINDINGS: Recent studies show that the human glycome (the repertoire of human glycan structures) plays critical roles in driving or modulating several cellular processes and immunological functions that are central to maintaining HIV infection. Understanding the links between glycoimmunology and HIV infection may create a new paradigm for discovering novel glycan-based therapies that can lead to eradication, functional cure, or improved tolerance of lifelong infection.

Glycosylation of Zika Virus is Important in Host-Virus Interaction and Pathogenic Potential.

Zika virus (ZIKV) is a global public health issue due to its association with severe developmental disorders in infants and neurological disorders in adults. ZIKV uses glycosylation of its envelope (E) protein to interact with host cell receptors to facilitate entry; these interactions could also be important for designing therapeutics and vaccines. Due to a lack of proper information about Asn-linked (N-glycans) on ZIKV E, we analyzed ZIKV E of various strains derived from different cells. We found ZIKV E proteins being extensively modified with oligomannose, hybrid and complex N-glycans of a highly heterogeneous nature. Host cell surface glycans correlated strongly with the glycomic features of ZIKV E. Mechanistically, we observed that ZIKV N-glycans might play a role in viral pathogenesis, as mannose-specific C-type lectins DC-SIGN and L-SIGN mediate host cell entry of ZIKV. Our findings represent the first detailed mapping of N-glycans on ZIKV E of various strains and their functional significance.

Distinct intestinal microbial signatures linked to accelerated systemic and intestinal biological aging.

BACKGROUND: People living with HIV (PLWH), even when viral replication is controlled through antiretroviral therapy (ART), experience persistent inflammation. This inflammation is partly attributed to intestinal microbial dysbiosis and translocation, which may lead to non-AIDS-related aging-associated comorbidities. The extent to which living with HIV - influenced by the infection itself, ART usage, sexual orientation, or other associated factors - affects the biological age of the intestines is unclear. Furthermore, the role of microbial dysbiosis and translocation in the biological aging of PLWH remains to be elucidated. To investigate these uncertainties, we used a systems biology approach, analyzing colon and ileal biopsies, blood samples, and stool specimens from PLWH on ART and people living without HIV (PLWoH) as controls. RESULTS: PLWH exhibit accelerated biological aging in the colon, ileum, and blood, as measured by various epigenetic aging clocks, compared to PLWoH. Investigating the relationship between microbial translocation and biological aging, PLWH had decreased levels of tight junction proteins in the intestines, along with increased microbial translocation. This intestinal permeability correlated with faster biological aging and increased inflammation. When investigating the relationship between microbial dysbiosis and biological aging, the intestines of PLWH had higher abundance of specific pro-inflammatory bacteria, such as Catenibacterium and Prevotella. These bacteria correlated with accelerated biological aging. Conversely, the intestines of PLWH had lower abundance of bacteria known for producing the anti-inflammatory short-chain fatty acids, such as Subdoligranulum and Erysipelotrichaceae, and these bacteria were associated with slower biological aging. Correlation networks revealed significant links between specific microbial genera in the colon and ileum (but not in feces), increased aging, a rise in pro-inflammatory microbe-related metabolites (e.g., those in the tryptophan metabolism pathway), and a decrease in anti-inflammatory metabolites like hippuric acid. CONCLUSIONS: We identified specific microbial compositions and microbiota-related metabolic pathways that are intertwined with intestinal and systemic biological aging. This microbial signature of biological aging is likely reflecting various factors including the HIV infection itself, ART usage, sexual orientation, and other aspects associated with living with HIV. A deeper understanding of the mechanisms underlying these connections could offer potential strategies to mitigate accelerated aging and its associated health complications. Video Abstract.

Predictors of HIV rebound differ by timing of antiretroviral therapy initiation.

BACKGROUNDIdentifying factors that predict the timing of HIV rebound after treatment interruption will be crucial for designing and evaluating interventions for HIV remission.METHODSWe performed a broad evaluation of viral and immune factors that predict viral rebound (AIDS Clinical Trials Group A5345). Participants initiated antiretroviral therapy (ART) during chronic (N = 33) or early (N = 12) HIV infection with ≥ 2 years of suppressive ART and restarted ART if they had 2 viral loads ≥ 1,000 copies/mL after treatment interruption.RESULTSCompared with chronic-treated participants, early-treated individuals had smaller and fewer transcriptionally active HIV reservoirs. A higher percentage of HIV Gag-specific CD8+ T cell cytotoxic response was associated with lower intact proviral DNA. Predictors of HIV rebound timing differed between early- versus chronic-treated participants, as the strongest reservoir predictor of time to HIV rebound was level of residual viremia in early-treated participants and intact DNA level in chronic-treated individuals. We also identified distinct sets of pre-treatment interruption viral, immune, and inflammatory markers that differentiated participants who had rapid versus slow rebound.CONCLUSIONThe results provide an in-depth overview of the complex interplay of viral, immunologic, and inflammatory predictors of viral rebound and demonstrate that the timing of ART initiation modifies the features of rapid and slow viral rebound.TRIAL REGISTRATIONClinicalTrials.gov NCT03001128FUNDINGNIH National Institute of Allergy and Infectious Diseases, Merck.

Immunoglobulin G N-glycan markers of accelerated biological aging during chronic HIV infection.

People living with HIV (PLWH) experience increased vulnerability to premature aging and inflammation-associated comorbidities, even when HIV replication is suppressed by antiretroviral therapy (ART). However, the factors associated with this vulnerability remain uncertain. In the general population, alterations in the N-glycans on IgGs trigger inflammation and precede the onset of aging-associated diseases. Here, we investigate the IgG N-glycans in cross-sectional and longitudinal samples from 1214 women and men, living with and without HIV. PLWH exhibit an accelerated accumulation of pro-aging-associated glycan alterations and heightened expression of senescence-associated glycan-degrading enzymes compared to controls. These alterations correlate with elevated markers of inflammation and the severity of comorbidities, potentially preceding the development of such comorbidities. Mechanistically, HIV-specific antibodies glycoengineered with these alterations exhibit a reduced ability to elicit anti-HIV Fc-mediated immune activities. These findings hold potential for the development of biomarkers and tools to identify and prevent premature aging and comorbidities in PLWH.

Human galectin-9 promotes the expansion of HIV reservoirs in vivo in humanized mice.

OBJECTIVE: The human endogenous protein galectin-9 (Gal-9) reactivates latently HIV-infected cells in vitro and ex vivo , which may allow for immune-mediated clearance of these cells. However, Gal-9 also activates several immune cells, which could negatively affect HIV persistence by promoting chronic activation/exhaustion. This potential 'double-edged sword' effect of Gal-9 raises the question of the overall impact of Gal-9 on HIV persistence in vivo . DESIGN: We used the BLT (bone marrow, liver, thymus) humanized mouse model to evaluate the impact of Gal-9 on HIV persistence in vivo during antiretroviral therapy (ART). METHODS: Two independent cohorts of ART-suppressed HIV-infected BLT mice were treated with either recombinant Gal-9 or phosphate-buffered saline control. Plasma viral loads and levels of tissue-associated HIV DNA and RNA were measured by qPCR. Immunohistochemistry and HIV RNAscope were used to quantify CD4 + T, myeloid, and HIV RNA+ cells in tissues. T cell activation and exhaustion were measured by flow cytometry, and plasma markers of inflammation were measured by multiplex cytokine arrays. RESULTS: Gal-9 did not induce plasma markers of inflammation or T cell markers of activation/exhaustion in vivo . However, the treatment significantly increased levels of tissue-associated HIV DNA and RNA compared to controls ( P  = 0.0007 and P  = 0.011, respectively, for cohort I and P  = 0.002 and P  = 0.005, respectively, for cohort II). RNAscope validated the Gal-9 mediated induction of HIV RNA in tissue-associated myeloid cells, but not T cells. CONCLUSIONS: Our study highlights the overall adverse effects of Gal-9 on HIV persistence and the potential need to block Gal-9 interactions during ART-suppressed HIV infection.

Siglec-9 Restrains Antibody-Dependent Natural Killer Cell Cytotoxicity against SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection alters the immunological profiles of natural killer (NK) cells. However, whether NK antiviral functions are impaired during severe coronavirus disease 2019 (COVID-19) and what host factors modulate these functions remain unclear. We found that NK cells from hospitalized COVID-19 patients degranulate less against SARS-CoV-2 antigen-expressing cells (in direct cytolytic and antibody-dependent cell cytotoxicity [ADCC] assays) than NK cells from mild COVID-19 patients or negative controls. The lower NK degranulation was associated with higher plasma levels of SARS-CoV-2 nucleocapsid antigen. Phenotypic and functional analyses showed that NK cells expressing the glyco-immune checkpoint Siglec-9 elicited higher ADCC than Siglec-9- NK cells. Consistently, Siglec-9+ NK cells exhibit an activated and mature phenotype with higher expression of CD16 (FcγRIII; mediator of ADCC), CD57 (maturation marker), and NKG2C (activating receptor), along with lower expression of the inhibitory receptor NKG2A, than Siglec-9- CD56dim NK cells. These data are consistent with the concept that the NK cell subpopulation expressing Siglec-9 is highly activated and cytotoxic. However, the Siglec-9 molecule itself is an inhibitory receptor that restrains NK cytotoxicity during cancer and other viral infections. Indeed, blocking Siglec-9 significantly enhanced the ADCC-mediated NK degranulation and lysis of SARS-CoV-2-antigen-positive target cells. These data support a model in which the Siglec-9+ CD56dim NK subpopulation is cytotoxic even while it is restrained by the inhibitory effects of Siglec-9. Alleviating the Siglec-9-mediated restriction on NK cytotoxicity may further improve NK immune surveillance and presents an opportunity to develop novel immunotherapeutic tools against SARS-CoV-2 infected cells. IMPORTANCE One mechanism that cancer cells use to evade natural killer cell immune surveillance is by expressing high levels of sialoglycans, which bind to Siglec-9, a glyco-immune checkpoint molecule on NK cells. This binding inhibits NK cell cytotoxicity. Several viruses, such as hepatitis B virus (HBV) and HIV, also use a similar mechanism to evade NK surveillance. We found that NK cells from SARS-CoV-2-hospitalized patients are less able to function against cells expressing SARS-CoV-2 Spike protein than NK cells from SARS-CoV-2 mild patients or uninfected controls. We also found that the cytotoxicity of the Siglec-9+ NK subpopulation is indeed restrained by the inhibitory nature of the Siglec-9 molecule and that blocking Siglec-9 can enhance the ability of NK cells to target cells expressing SARS-CoV-2 antigens. Our results suggest that a targetable glyco-immune checkpoint mechanism, Siglec-9/sialoglycan interaction, may contribute to the ability of SARS-CoV-2 to evade NK immune surveillance.

Distinct Intestinal Microbial Signatures Linked to Accelerated Biological Aging in People with HIV.

Background: People with HIV (PWH), even with controlled viral replication through antiretroviral therapy (ART), experience persistent inflammation. This is partly due to intestinal microbial dysbiosis and translocation. Such ongoing inflammation may lead to the development of non-AIDS-related aging-associated comorbidities. However, there remains uncertainty regarding whether HIV affects the biological age of the intestines and whether microbial dysbiosis and translocation influence the biological aging process in PWH on ART. To fill this knowledge gap, we utilized a systems biology approach, analyzing colon and ileal biopsies, blood samples, and stool specimens from PWH on ART and their matched HIV-negative counterparts. Results: Despite having similar chronological ages, PWH on ART exhibit accelerated biological aging in the colon, ileum, and blood, as measured by various epigenetic aging clocks, compared to HIV-negative controls. Investigating the relationship between microbial translocation and biological aging, PWH on ART had decreased levels of tight junction proteins in the colon and ileum, along with increased microbial translocation. This increased intestinal permeability correlated with faster intestinal and systemic biological aging, as well as increased systemic inflammation. When investigating the relationship between microbial dysbiosis and biological aging, the intestines of PWH on ART had higher abundance of specific pro-inflammatory bacterial genera, such as Catenibacterium and Prevotella. These bacteria significantly correlated with accelerated local and systemic biological aging. Conversely, the intestines of PWH on ART had lower abundance of bacterial genera known for producing short-chain fatty acids and exhibiting anti-inflammatory properties, such as Subdoligranulum and Erysipelotrichaceae, and these bacteria taxa were associated with slower biological aging. Correlation networks revealed significant links between specific microbial genera in the colon and ileum (but not in feces), increased aging, a rise in pro-inflammatory microbial-related metabolites (e.g., those in the tryptophan metabolism pathway), and a decrease in anti-inflammatory metabolites like hippuric acid and oleic acid. Conclusions: We identified a specific microbial composition and microbiome-related metabolic pathways that are intertwined with both intestinal and systemic biological aging in PWH on ART. A deeper understanding of the mechanisms underlying these connections could potentially offer strategies to counteract premature aging and its associated health complications in PWH.

Plasma Glycomic Markers of Accelerated Biological Aging During Chronic HIV Infection.

People with HIV (PWH) experience an increased vulnerability to premature aging and inflammation-associated comorbidities, even when HIV replication is suppressed by antiretroviral therapy (ART). However, the factors that contribute to or are associated with this vulnerability remain uncertain. In the general population, alterations in the glycomes of circulating IgGs trigger inflammation and precede the onset of aging-associated diseases. Here, we investigate the IgG glycomes of cross-sectional and longitudinal samples from 1,216 women and men, both living with virally suppressed HIV and those without HIV. Our glycan-based machine learning models indicate that living with chronic HIV significantly accelerates the accumulation of pro-aging-associated glycomic alterations. Consistently, PWH exhibit heightened expression of senescence-associated glycan-degrading enzymes compared to their controls. These glycomic alterations correlate with elevated markers of inflammatory aging and the severity of comorbidities, potentially preceding the development of such comorbidities. Mechanistically, HIV-specific antibodies glycoengineered with these alterations exhibit reduced anti-HIV IgG-mediated innate immune functions. These findings hold significant potential for the development of glycomic-based biomarkers and tools to identify and prevent premature aging and comorbidities in people living with chronic viral infections.

Comparative effectiveness of dried-plasma hepatitis B virus viral load (VL) testing in three different VL commercial platforms using ViveST for sample collection.

Ninety-six samples from hepatitis B virus (HBV)-infected individuals were used to compare ViveST samples to frozen samples in COBAS TaqMan, RealArt, and VERSANT. Correlation (r) between ViveST samples and frozen samples was 0.99 in all three platforms. Correlations among tests using frozen samples were 0.96 for COBAS and RealArt, 0.94 for COBAS and VERSANT, and 0.97 for VERSANT and RealArt. The results indicate that ViveST may be useful in clinical practice. Different HBV-VL platforms correlated well with one another.

Examining the Impact of Galectin-9 on Latent HIV Transcription.

The ß-galactoside-binding protein Galectin-9 (Gal-9) functions as a double-edged sword during HIV infection. On the one hand, Gal-9 can reactivate HIV latently infected cells, the main barrier to achieving HIV eradication, making them visible to immune clearance. On the other hand, Gal-9 induces latent HIV transcription by activating T cell Receptor (TCR) signaling pathways. These signaling pathways induce undesirable pro-inflammatory responses. While these unwanted responses can be mitigated by rapamycin without impacting Gal-9-mediated latent HIV reactivation, this effect raises the concern that Gal-9 may play a role in the chronic immune activation/inflammation that persists in people living with HIV despite antiretroviral therapy. Together, these data highlight the need to understand the positive and negative impacts of galectin interactions on immunological functions during HIV infection. In this chapter, we describe methods that can be used to investigate the effects of galectins, in particular Gal-9, on latent HIV transcription in vitro and ex vivo.

Methadone use is associated with increased levels of sCD14, immune activation, and inflammation during suppressed HIV infection.

Opioid use has negative effects on immune responses and may impair immune reconstitution in persons living with HIV (PLWH) infection undergoing antiretroviral treatment (ART). The effects of treatment with µ opioid receptor (MOR) agonists (e.g., methadone, MET) and antagonists (e.g., naltrexone, NTX) on immune reconstitution and immune activation in ART-suppressed PLWH have not been assessed in-depth. We studied the effects of methadone or naltrexone on measures of immune reconstitution and immune activation in a cross-sectional community cohort of 30 HIV-infected individuals receiving suppressive ART and medications for opioid use disorder (MOUD) (12 MET, 8 NTX and 10 controls). Plasma markers of inflammation and immune activation were measured using ELISA, Luminex, or Simoa. Plasma IgG glycosylation was assessed using capillary electrophoresis. Cell subsets and activation were studied using whole blood flow cytometry. Individuals in the MET group, but no in the NTX group, had higher plasma levels of inflammation and immune activation markers than controls. These markers include soluble CD14 (an independent predictor of morbidity and mortality during HIV infection), proinflammatory cytokines, and proinflammatory IgG glycans. This effect was independent of time on treatment. Our results indicate that methadone-based MOUD regimens may sustain immune activation and inflammation in ART-treated HIV-infected individuals. Our pilot study provides the foundation and rationale for future longitudinal functional studies of the impact of MOUD regimens on immune reconstitution and residual activation after ART-mediated suppression.

Circulating brain-derived extracellular vesicles expressing neuroinflammatory markers are associated with HIV-related neurocognitive impairment.

Background: Neurocognitive impairment remains prevalent in people with HIV (PWH) despite long term virological suppression by antiretroviral therapy (ART) regimens. Systemic and neuro-inflammatory processes are suggested to contribute to the complex pathology leading to cognitive impairment in this population, yet the underlying mechanisms remain unresolved. Extracellular vesicles (EVs) play a central role in intracellular communication and have emerged as key modulators of immunological and inflammatory responses. In this report, we examined the impact of EVs in PWH experiencing cognitive deficits to determine their relevance in HIV associated neuropathology. Methods: EV phenotypes were measured in plasma samples from 108 PWH with either cognitive impairment (CI, n=92) or normal cognition (NC, n=16) by flow cytometry. Matched cerebrospinal fluid (CSF)-derived EVs were similarly profiled from a subgroup of 84 individuals who underwent a lumbar puncture. Peripheral blood mononuclear cells were assayed by flow cytometry to measure monocyte frequencies in a subset of 32 individuals. Results: Plasma-EVs expressing CD14, CD16, CD192, C195, and GFAP were significantly higher in HIV-infected individuals with cognitive impairment compared to individuals with normal cognition. Increased CSF-EVs expressing GFAP and CD200 were found in the cognitive impairment group compared to the normal cognition group. Frequencies of patrolling monocytes correlated with plasma-EVs expressing CD14, CD66b, MCSF, MAP2, and GFAP. Frequencies of CD195 expression on monocytes correlated positively with plasma-EVs expressing CD41a, CD62P, and CD63. Expression of CD163 on monocytes correlated positively with CSF-EVs expressing GFAP and CD200. Finally, the expression of CD192 on total monocytes correlated with CSF-EVs expressing CD200, CD62P, and CD63. Conclusions: EVs expressing monocyte activation and neuronal markers associated with HIV associated cognitive impairment, suggesting that distinct EV subsets may serve as novel biomarkers of neuronal injury in HIV infection. Further circulating platelet EV levels were linked to monocyte activation indicating a potential novel interaction in the pathogenesis of HIV-related cognitive impairment.

Markers of fungal translocation are elevated during post-acute sequelae of SARS-CoV-2 and induce NF-κB signaling.

Long COVID, a type of post-acute sequelae of SARS-CoV-2 (PASC), has been associated with sustained elevated levels of immune activation and inflammation. However, the mechanisms that drive this inflammation remain unknown. Inflammation during acute coronavirus disease 2019 could be exacerbated by microbial translocation (from the gut and/or lung) to blood. Whether microbial translocation contributes to inflammation during PASC is unknown. We did not observe a significant elevation in plasma markers of bacterial translocation during PASC. However, we observed higher levels of fungal translocation - measured as ß-glucan, a fungal cell wall polysaccharide - in the plasma of individuals experiencing PASC compared with those without PASC or SARS-CoV-2-negative controls. The higher ß-glucan correlated with higher inflammation and elevated levels of host metabolites involved in activating N-methyl-d-aspartate receptors (such as metabolites within the tryptophan catabolism pathway) with established neurotoxic properties. Mechanistically, ß-glucan can directly induce inflammation by binding to myeloid cells (via Dectin-1) and activating Syk/NF-κB signaling. Using a Dectin-1/NF-κB reporter model, we found that plasma from individuals experiencing PASC induced higher NF-κB signaling compared with plasma from negative controls. This higher NF-κB signaling was abrogated by piceatannol (Syk inhibitor). These data suggest a potential targetable mechanism linking fungal translocation and inflammation during PASC.

Abnormal food timing and predisposition to weight gain: Role of barrier dysfunction and microbiota.

Obesity has become a common rising health care problem, especially in "modern" societies. Obesity is considered a low-grade systemic inflammation, partly linked to leaky gut. Circadian rhythm disruption, a common habit in modern life, has been reported to cause gut barrier impairment. Abnormal time of eating, defined by eating close to or during rest time, is shown to cause circadian rhythm disruption. Here, using a non-obesogenic diet, we found that abnormal feeding time facilitated weight gain and induced metabolic dysregulation in mice. The effect of abnormal time of eating was associated with increased gut permeability, estimated by sucralose and/or lactulose ratio and disrupted intestinal barrier marker. Analysis of gut microbiota and their metabolites, as important regulators of barrier homeostasis, revealed that abnormal food timing reduced relative abundance of butyrate-producing bacteria, and the colonic butyrate level. Overall, our data supported that dysbiosis was characterized by increased intestinal permeability and decreased beneficial barrier butyrate-producing bacteria and/or metabolite to mechanistically link the time of eating to obesity. This data provides basis for noninvasive microbial-targeted interventions to improve intestinal barrier function as new opportunities for combating circadian rhythm disruption induced metabolic dysfunction.