Inhibition of caspase pathways limits CD4+ T cell loss and restores host anti-retroviral function in HIV-1 infected humanized mice with augmented lymphoid tissue.

The study of HIV infection and pathogenicity in physical reservoirs requires a biologically relevant model. The human immune system (HIS) mouse is an established model of HIV infection, but defects in immune tissue reconstitution remain a challenge for examining pathology in tissues. We utilized exogenous injection of the human recombinant FMS-like tyrosine kinase 3 ligand (rFLT-3 L) into the hematopoietic stem cell (HSC) cord blood HIS mouse model to significantly expand the total area of lymph node (LN) and the number of circulating human T cells. The results enabled visualization and quantification of HIV infectivity, CD4 T cell depletion and other measures of pathogenesis in the secondary lymphoid tissues of the spleen and LN. Treatment with the Caspase-1/4 inhibitor VX-765 limited CD4+ T cell loss in the spleen and reduced viral load in both the spleen and axillary LN. In situ hybridization further demonstrated a decrease in viral RNA in both the spleen and LN. Transcriptomic analysis revealed that in vivo inhibition of caspase-1/4 led to an upregulation in host HIV restriction factors including SAMHD1 and APOBEC3A. These findings highlight the use of rFLT-3 L to augment human immune system characteristics in HIS mice to support investigations of HIV pathogenesis and test host directed therapies, though further refinements are needed to further augment LN architecture and cellular populations. The results further provide in vivo evidence of the potential to target inflammasome pathways as an avenue of host-directed therapy to limit immune dysfunction and virus replication in tissue compartments of HIV+ persons.

Longitudinal analysis of CSF HIV RNA in untreated people with HIV: Identification of CSF controllers.

Interindividual variation of human immunodeficiency virus (HIV) RNA setpoint in cerebrospinal fluid (CSF) and its determinants are poorly understood, but relevant for HIV neuropathology, brain reservoirs, viral escape, and reseeding after antiretroviral interruptions. Longitudinal multicentric study on demographic, clinical, and laboratory correlates of CSF HIV RNA in 2000 follow-up visits from 597 people with HIV (PWH) off antiretroviral therapy (ART) and with plasma HIV RNA > the lower limit of quantification (LLQ). Factors associated with CSF control (CSFC; CSF HIV RNA < LLQ while plasma HIV RNA > LLQ) and with CSF/plasma discordance (CSF > plasma HIV RNA > LLQ) were also assessed through mixed-effects models. Posthoc and sensitivity analyses were performed for persistent CSFC and ART-naïve participants, respectively. Over a median follow-up of 2.1 years, CSF HIV RNA was associated with CD4+ and CD8+ T cells, CSF leukocytes, blood-brain barrier (BBB) integrity, biomarkers of iron and lipid metabolism, serum globulins, past exposure to lamivudine, and plasma HIV RNA (model p < 0.0001). CSFC (persistent in 7.7% over 3 years) and CSF/plasma discordance (persistent in <0.01% over 1 year) were variably associated with the same parameters (model p < 0.001). Sensitivity analyses confirmed most of the previous associations in participants never exposed to ART. Persistent CSFC was associated with higher CD4+ T-cell count nadir (p < 0.001), lower serum globulins (p = 0.003), and lower CSF leukocytes (p < 0.001). Without ART, one in 13 PWH had persistently undetectable CSF HIV RNA, while persistent CSF/plasma discordance was extremely rare over years. Immune responses, inflammation, BBB permeability, and iron and lipid metabolism were all associated with HIV replication in CSF.

A critical role for Macrophage-derived Cysteinyl-Leukotrienes in HIV-1 induced neuronal injury.

Macrophages (MΦ) infected with human immunodeficiency virus (HIV)-1 or activated by its envelope protein gp120 exert neurotoxicity. We found previously that signaling via p38 mitogen-activated protein kinase (p38 MAPK) is essential to the neurotoxicity of HIVgp120-stimulated MΦ. However, the associated downstream pathways remained elusive. Here we show that cysteinyl-leukotrienes (CysLT) released by HIV-infected or HIVgp120 stimulated MΦ downstream of p38 MAPK critically contribute to neurotoxicity. SiRNA-mediated or pharmacological inhibition of p38 MAPK deprives MΦ of CysLT synthase (LTC4S) and, pharmacological inhibition of the cysteinyl-leukotriene receptor 1 (CYSLTR1) protects cerebrocortical neurons against toxicity of both gp120-stimulated and HIV-infected MΦ. Components of the CysLT pathway are differentially regulated in brains of HIV-infected individuals and a transgenic mouse model of NeuroHIV (HIVgp120tg). Moreover, genetic ablation of LTC4S or CysLTR1 prevents neuronal damage and impairment of spatial memory in HIVgp120tg mice. Altogether, our findings suggest a novel critical role for cysteinyl-leukotrienes in HIV-associated brain injury.

Caspase cleavage of gasdermin E causes neuronal pyroptosis in HIV-associated neurocognitive disorder.

Despite effective antiretroviral therapies, 20-30% of persons with treated HIV infection develop a neurodegenerative syndrome termed HIV-associated neurocognitive disorder (HAND). HAND is driven by HIV expression coupled with inflammation in the brain but the mechanisms underlying neuronal damage and death are uncertain. The inflammasome-pyroptosis axis coordinates an inflammatory type of regulated lytic cell death that is underpinned by the caspase-activated pore-forming gasdermin proteins. The mechanisms driving neuronal pyroptosis were investigated herein in models of HAND, using multi-platform molecular and morphological approaches that included brain tissues from persons with HAND and simian immunodeficiency virus (SIV)-infected non-human primates as well as cultured human neurons. Neurons in the frontal cortices from persons with HAND showed increased cleaved gasdermin E (GSDME), which was associated with ß-III tubulin degradation and increased HIV levels. Exposure of cultured human neurons to the HIV-encoded viral protein R (Vpr) elicited time-dependent cleavage of GSDME and Ninjurin-1 (NINJ1) induction with associated cell lysis that was inhibited by siRNA suppression of both proteins. Upstream of GSDME cleavage, Vpr exposure resulted in activation of caspases-1 and 3. Pretreatment of Vpr-exposed neurons with the caspase-1 inhibitor, VX-765, reduced cleavage of both caspase-3 and GSDME, resulting in diminished cell death. To validate these findings, we examined frontal cortical tissues from SIV-infected macaques, disclosing increased expression of GSDME and NINJ1 in cortical neurons, which was co-localized with caspase-3 detection in animals with neurological disease. Thus, HIV infection of the brain triggers the convergent activation of caspases-1 and -3, which results in GSDME-mediated neuronal pyroptosis in persons with HAND. These findings demonstrate a novel mechanism by which a viral infection causes pyroptotic death in neurons while also offering new diagnostic and therapeutic strategies for HAND and other neurodegenerative disorders.

Elevated Plasma Protein Carbonyl Concentration Is Associated with More Abnormal White Matter in People with HIV.

Structural brain abnormalities, including those in white matter (WM), remain common in people with HIV (PWH). Their pathogenesis is uncertain and may reflect multiple etiologies. Oxidative stress is associated with inflammation, HIV, and its comorbidities. The post-translational carbonylation of proteins results from oxidative stress, and circulating protein carbonyls may reflect this. In this cross-sectional analysis, we evaluated the associations between protein carbonyls and a panel of soluble biomarkers of neuronal injury and inflammation in plasma (N = 45) and cerebrospinal fluid (CSF, n = 32) with structural brain MRI. The volume of abnormal WM was normalized for the total WM volume (nAWM). In this multisite project, all regression models were adjusted for the scanner. The candidate covariates included demographics, HIV disease characteristics, and comorbidities. Participants were PWH on virally suppressive antiretroviral therapy (ART) and were mostly white (64.4%) men (88.9%), with a mean age of 56.8 years. In unadjusted analyses, more nAWM was associated with higher plasma protein carbonyls (p = 0.002) and higher CCL2 (p = 0.045). In the adjusted regression models for nAWM, the association with plasma protein carbonyls remained significant (FDR p = 0.018). Protein carbonyls in plasma may be a valuable biomarker of oxidative stress and its associated adverse health effects, including within the central nervous system. If confirmed, these findings would support the hypothesis that reducing oxidative stress could treat or prevent WM injury in PWH.

Increasing Neuroinflammation Relates to Increasing Neurodegeneration in People with HIV.

BACKGROUND: HIV infection causes neuroinflammation and immune activation (NIIA) and systemic inflammation and immune activation (SIIA), which in turn drive neurodegeneration (ND). Cross-sectionally, higher levels of NIIA biomarkers correlate with increased biomarkers of ND. A more convincing confirmation would be a longitudinal demonstration. METHODS: PWH in the US multisite CHARTER Aging project were assessed at a baseline visit and after 12 years using standardized evaluations. We measured a panel of 14 biomarkers of NIIA, SIIA, and ND in plasma and CSF at two time points and calculated changes from baseline to the 12-year visit. Factor analysis yielded simplified indices of NIIA, SIIA, and ND. RESULTS: The CSF NIIA factor analysis yielded Factor1 loading on soluble tumor necrosis factor type-2 (sTNFR-II) and neopterin, and Factor2, loading on MCP1, soluble CD14, and IL-6. The SIIA factor analysis yielded Factor1 loading on CRP, D-dimer, and Neopterin; Factor2 loading on sTNFR-II. The ND analysis yielded Factor1 loading on Phosphorylated tau (p-tau) and Aß42; Factor2 loading on NFL. NIIA Factor1, but not Factor2, correlated with increases in CSF NFL (r = 0.370, p = 0.0002). CONCLUSIONS: Increases in NIIA and SIIA in PWH were associated with corresponding increases in ND, suggesting that reducing neuro/systemic inflammation might slow or reverse neurodegeneration.

Intact Proviral DNA Analysis of the Brain Viral Reservoir and Relationship to Neuroinflammation in People with HIV on Suppressive Antiretroviral Therapy.

HIV establishes a persistent viral reservoir in the brain despite viral suppression in blood to undetectable levels on antiretroviral therapy (ART). The brain viral reservoir in virally suppressed HIV+ individuals is not well-characterized. In this study, intact, defective, and total HIV proviral genomes were measured in frontal lobe white matter from 28 virally suppressed individuals on ART using the intact proviral DNA assay (IPDA). HIV gag DNA/RNA levels were measured using single-copy assays and expression of 78 genes related to inflammation and white matter integrity was measured using the NanoString platform. Intact proviral DNA was detected in brain tissues of 18 of 28 (64%) individuals on suppressive ART. The median proviral genome copy numbers in brain tissue as measured by the IPDA were: intact, 10 (IQR 1-92); 3' defective, 509 (225-858); 5' defective, 519 (273-906); and total proviruses, 1063 (501-2074) copies/106 cells. Intact proviral genomes accounted for less than 10% (median 8.3%) of total proviral genomes in the brain, while 3' and 5' defective genomes accounted for 44% and 49%, respectively. There was no significant difference in median copy number of intact, defective, or total proviruses between groups stratified by neurocognitive impairment (NCI) vs. no NCI. In contrast, there was an increasing trend in intact proviruses in brains with vs. without neuroinflammatory pathology (56 vs. 5 copies/106 cells, p = 0.1), but no significant differences in defective or total proviruses. Genes related to inflammation, stress responses, and white matter integrity were differentially expressed in brain tissues with >5 vs. +5 intact proviruses/106 cells. These findings suggest that intact HIV proviral genomes persist in the brain at levels comparable to those reported in blood and lymphoid tissues and increase CNS inflammation/immune activation despite suppressive ART, indicating the importance of targeting the CNS reservoir to achieve HIV cure.

The HIV Restriction Factor Profile in the Brain Is Associated with the Clinical Status and Viral Quantities.

HIV-encoded DNA, RNA and proteins persist in the brain despite effective antiretroviral therapy (ART), with undetectable plasma and cerebrospinal fluid viral RNA levels, often in association with neurocognitive impairments. Although the determinants of HIV persistence have garnered attention, the expression and regulation of antiretroviral host restriction factors (RFs) in the brain for HIV and SIV remain unknown. We investigated the transcriptomic profile of antiretroviral RF genes by RNA-sequencing with confirmation by qRT-PCR in the cerebral cortex of people who are uninfected (HIV[-]), those who are HIV-infected without pre-mortem brain disease (HIV[+]), those who are HIV-infected with neurocognitive disorders (HIV[+]/HAND) and those with neurocognitive disorders with encephalitis (HIV[+]/HIVE). We observed significant increases in RF expression in the brains of HIV[+]/HIVE in association with the brain viral load. Machine learning techniques identified MAN1B1 as a key gene that distinguished the HIV[+] group from the HIV[+] groups with HAND. Analyses of SIV-associated RFs in brains from SIV-infected Chinese rhesus macaques with different ART regimens revealed diminished RF expression among ART-exposed SIV-infected animals, although ART interruption resulted in an induced expression of several RF genes including OAS3, RNASEL, MX2 and MAN1B1. Thus, the brain displays a distinct expression profile of RFs that is associated with the neurological status as well as the brain viral burden. Moreover, ART interruption can influence the brain's RF profile, which might contribute to disease outcomes.

Higher Levels of Cerebrospinal Fluid and Plasma Neurofilament Light in Human Immunodeficiency Virus-Associated Distal Sensory Polyneuropathy.

BACKGROUND: Neurofilament light (NFL) chain concentrations, reflecting axonal damage, are seen in several polyneuropathies but have not been studied in human immunodeficiency virus (HIV) distal sensory polyneuropathy (DSP). We evaluated NFL in cerebrospinal fluid (CSF) and plasma in relation to DSP in people with HIV (PWH) from 2 independent cohorts and in people without HIV (PWoH). METHODS: Cohort 1 consisted of PWH from the CHARTER Study. Cohort 2 consisted of PWH and PWoH from the HIV Neurobehavioral Research Center (HNRC). We evaluated DSP signs and symptoms in both cohorts. Immunoassays measured NFL in CSF for all and for plasma as well in Cohort 2. RESULTS: Cohort 1 consisted of 111 PWH, mean ± SD age 56.8 ± 8.32 years, 15.3% female, 38.7% Black, 49.6% White, current CD4+ T-cells (median, interquartile range [IQR]) 532/µL (295, 785), 83.5% with plasma HIV RNA ≤50 copies/mL. Cohort 2 consisted of 233 PWH of similar demographics to PWH in Cohort 1 but also 51 PWoH, together age 58.4 ± 6.68 years, 41.2% female, 18.0% Black, Hispanic, non-Hispanic White 52.0%, 6.00% White. In both cohorts of PWH, CSF and plasma NFL were significantly higher in both PWH with DSP signs. Findings were similar, albeit not significant, for PWoH. The observed relationships were not explained by confounds. CONCLUSIONS: Both plasma and CSF NFL were elevated in PWH and PWoH with DSP. The convergence of our findings with others demonstrates that NFL is a reliable biomarker reflecting peripheral nerve injury. Biomarkers such as NFL might provide, validate, and optimize clinical trials of neuroregenerative strategies in HIV DSP.

Twelve-year neurocognitive decline in HIV is associated with comorbidities, not age: a CHARTER study.

Modern antiretroviral therapy (ART) has increased longevity of people with HIV and shifted the age distribution of the HIV pandemic upward toward that of the general population. This positive development has also led to concerns about premature and/or accelerated neurocognitive and physical ageing due to the combined effects of chronic HIV, accumulating comorbidities, adverse effects or possible toxicities of ART and biological ageing. Here we present results of comprehensive assessments over 12 years of 402 people with HIV in the CNS HIV ART Effects Research (CHARTER) programme, who at follow-up were composed of younger (<60 years) and older (≥60 years) subgroups. Over the 12 years, ART use and viral suppression increased in both subgroups as did systemic and psychiatric comorbidities; participants in both subgroups also evidenced neurocognitive decline beyond what is expected in typical ageing. Contrary to expectations, all these adverse effects were comparable in the younger and older CHARTER subgroups, and unrelated to chronological age. Neurocognitive decline was unrelated to HIV disease or treatment characteristics but was significantly predicted by the presence of comorbid conditions, specifically diabetes, hypertension, chronic pulmonary disease, frailty, neuropathic pain, depression and lifetime history of cannabis use disorder. These results are not consistent with premature or accelerated neurocognitive ageing due to HIV itself but suggest important indirect effects of multiple, potentially treatable comorbidities that are more common among people with HIV than in the general population. Good medical management of HIV disease did not prevent these adverse outcomes, and increased attention to a range of comorbid conditions in people with HIV may be warranted in their care.

Microbial molecule ingress promotes neuroinflammation and brain CCR5 expression in persons with HIV-associated neurocognitive disorders.

BACKGROUND: Systemic inflammation accompanies HIV-1 infection, resulting in microbial translocation from different tissues. We investigated interactions between lentivirus infections, neuroinflammation and microbial molecule presence in the brain. METHODS: Brain tissues from adult humans with (n = 22) and without HIV-1 (n = 11) infection as well as adult nonhuman primates (NHPs) with (n = 11) and without (n = 4) SIVmac251 infection were investigated by RT-PCR/ddPCR, immunofluorescence and western blotting. Studies of viral infectivity, host immune gene expression and viability were performed in primary human neural cells. FINDINGS: Among NHPs, SIV DNA quantitation in brain showed increased levels among animals with SIV encephalitis (n = 5) that was associated with bacterial genomic copy number as well as CCR5 and CASP1 expression in brain. Microbial DnaK and peptidoglycan were immunodetected in brains from uninfected and SIV-infected animals, chiefly in glial cells. Human microglia infected by HIV-1 showed increased p24 production after exposure to peptidoglycan that was associated CCR5 induction. HIV-1 Vpr application to human neurons followed by peptidoglycan exposure resulted in reduced mitochondrial function and diminished beta-III tubulin expression. In human brains, bacterial genome copies (250-550 copies/gm of tissue), were correlated with increased bacterial rRNA and GroEL transcript levels in patients with HIV-associated neurocognitive disorders (HAND). Glial cells displayed microbial GroEL and peptidoglycan immunoreactivity accompanied by CCR5 induction in brains from patients with HAND. INTERPRETATION: Increased microbial genomes and proteins were evident in brain tissues from lentivirus-infected humans and animals and associated with neurological disease. Microbial molecule translocation into the brain might exacerbate neuroinflammatory disease severity and represent a driver of lentivirus-associated brain disease.

Neuropathic pain correlates with worsening cognition in people with human immunodeficiency virus.

Neuropathic pain and cognitive impairment are among the HIV-related conditions that have most stubbornly resisted amelioration by virally suppressive antiretroviral therapy. Overlaps between the regional brain substrates and mechanisms of neuropathic pain and cognitive disorders are increasingly recognized, yet no studies have examined the longitudinal relationship between these two disorders. Participants in the prospective, observational CNS HIV AntiRetroviral Therapy Effects Research (CHARTER) cohort underwent standardized clinical evaluations for clinical examination findings of distal sensory polyneuropathy, reporting distal neuropathic pain and neurocognitive performance at study entry (baseline) and an average of 12 years later. Change in neuropathic pain and neuropathy status from baseline to follow-up was by self-report and repeat examination, and change in neurocognitive performance was assessed using a previously published summary regression-based change score. Relationships between incident or worsened neuropathic pain and neurocognitive change were evaluated using uni- and multivariable regressions, including age at baseline and other relevant covariates. Participants were 385 people with HIV, 91 (23.6%) females, mean ± standard deviation (SD) age at baseline 43.5 (7.81) years, ethnicity 44.9% African American, 10.6% Hispanic, 42.6% non-Hispanic white and 1.82% other. Baseline median (interquartile range) nadir CD4 was 175 (34 309) cells/µl and current CD4 was 454 (279 639). Incident or worsened distal neuropathic pain occurred in 98 (25.5%) over the follow-up period. People with HIV with incident or worsened distal neuropathic pain had significantly worsened neurocognitive performance at follow-up compared to those without incident or worsened distal neuropathic pain (summary regression-based change score mean ± SD -0.408 ± 0.700 versus -0.228 ± 0.613; P = 0.0158). This effect remained significant when considering viral suppression on antiretroviral therapy, incident diabetes and other covariates as predictors. Overall neurocognitive change related to neuropathic pain was driven primarily by changes in the domains of executive function and speed of information processing. Those with incident distal neuropathy signs did not have neurocognitive worsening, nor did individuals who used opioid analgesics or other pain-modulating drugs such as amitriptyline. Worsened neurocognitive performance in people with HIV was associated with worsened neuropathic pain but not with changes in physical signs of neuropathy, and this was not attributable to therapies for pain or depression or to differences in viral suppression. This finding implies that incident or worsened pain may signal increased risk for neurocognitive impairment, and deserves more investigation, particularly if better pain management might stabilize or improve neurocognitive performance.

Peripheral inflammation and depressed mood independently predict neurocognitive worsening over 12 years.

Background: Neurocognitive (NC) impairment in people with HIV (PWH) is associated with important adverse outcomes, but no markers exist to predict long-term NC decline. We evaluated depressed mood and markers of persistent inflammation, oxidative stress and altered amyloid processing (all common in PWH) as predictors of NC worsening over 12 years. Methods: PWH were enrolled and followed longitudinally in the CNS HIV Antiretroviral Effects Research (CHARTER) study at six US sites. At entry we quantified biomarkers in blood of inflammation: (interleukin-6 [IL-6], C-reactive protein [CRP], monocyte chemoattractant protein type 1 [MCP-1], D-dimer, soluble sCD14 (sCD14), soluble tumor necrosis factor receptor - type II [sTNFR-II], neopterin, and soluble CD40 ligand [sCD40L], oxidative stress (protein carbonyls, 8-oxo-2'-deoxyguanosine [8-oxo-dG]) and altered amyloid processing [amyloid beta (Aß)-42, soluble amyloid precursor protein-α (sAPPα)] using commercial immunoassays. The Beck Depression Inventory-II (BDI-II) assessed depressed mood at entry. NC decline over 12 years was evaluated using the published and validated summary (global) regression-based change score (sRBCS). A factor analysis reduced dimensionality of the biomarkers. Univariable and multiple regression models tested the relationship between baseline predictors and the outcome of neurocognitive decline. Results: Participants were 191 PWH, 37 (19.4%) women, 46.6% African American, 43.5% non-Hispanic white, 8.83% Hispanic, 15.7% white, 1.6% other; at study entry mean (SD) age 43.6 (8.06) years, estimated duration of HIV infection (median, IQR) 9.82 [4.44, 14.5] years, nadir CD4 104/µL (19,205), current CD4 568/µL (356, 817), and 80.1% had plasma HIV RNA <50 c/mL. Participants were enrolled between 2003 and 2007; median (IQR) duration of follow-up 12.4 [9.69, 16.2] years. Three biomarker factors were identified: Factor (F)1 (IL-6, CRP), F2 (sTNFR-II, neopterin) and F3 (sCD40L, sAPPα). Participants with higher F1, reflecting worse systemic inflammation at baseline, and higher F3, had greater decline in global neurocognition (r â€‹= â€‹-0.168, p â€‹= â€‹0.0205 and r â€‹= â€‹-0.156, p â€‹= â€‹0.0309, respectively). Of the F1 components, higher CRP levels were associated with worse decline (r â€‹= â€‹-0.154, p â€‹= â€‹0.0332), while IL-6 did not (r â€‹= â€‹-0.109, p â€‹= â€‹0.135). NC change was not significantly related to F2, nor to demographics, nadir and current CD4, viral suppression or baseline NC comorbidity ratings. Individuals with worse depressed mood at entry also experienced more NC decline (r â€‹= â€‹-0.1734, p â€‹= â€‹0.0006). Together BDI-II (p â€‹= â€‹0.0290), F1 (p â€‹= â€‹0.0484) and F3 (p â€‹= â€‹0.0309) contributed independently to NC decline (p â€‹= â€‹0.0028); their interactions were not significant. Neither CRP nor IL-6 correlated significantly with depression. Conclusions: PWH with greater systemic inflammation and more depression at entry had greater NC decline over 12 years. Understanding the basis of this inflammatory state might be particularly important. These findings raise the possibility that targeted anti-inflammatory or antidepressant therapies may help prevent NC worsening in PWH with depression and inflammation.

Higher buccal mitochondrial DNA and mitochondrial common deletion number are associated with markers of neurodegeneration and inflammation in cerebrospinal fluid.

Human immunodeficiency virus (HIV) infection is potentially associated with premature aging, but demonstrating this is difficult due to a lack of reliable biomarkers. The mitochondrial (mt) DNA "common deletion" mutation (mtCDM) is a 4977-bp deletion associated with aging and neurodegenerative diseases. We examined how mtDNA and mtCDM correlate with markers of neurodegeneration and inflammation in people with and without HIV (PWH and PWOH). Data from 149 adults were combined from two projects involving PWH (n = 124) and PWOH (n = 25). We measured buccal mtDNA and mtCDM by digital droplet PCR and compared them to disease and demographic characteristics and soluble biomarkers in cerebrospinal fluid (CSF) and blood measured by immunoassay. Participants had a median age of 52 years, with 53% white and 81% men. Median mtDNA level was 1,332 copies/cell (IQR 1,201-1,493) and median mtCDM level was 0.36 copies × 102/cell (IQR 0.31-0.42); both were higher in PWH. In the best model adjusting for HIV status and demographics, higher mtDNA levels were associated with higher CSF amyloid-ß 1-42 and 8-hydroxy-2'-deoxyguanosine and higher mtCDM levels were associated with higher plasma soluble tumor necrosis factor receptor II. The differences in mtDNA markers between PWH and PWOH support potential premature aging in PWH. Our findings suggest mtDNA changes in oral tissues may reflect CNS processes, allowing the use of inexpensive and easily accessible buccal biospecimens as a screening tool for CSF inflammation and neurodegeneration. Confirmatory and mechanistic studies on mt genome alterations by HIV and ART may identify interventions to prevent or treat neurodegenerative complications.

A neuron-to-astrocyte Wnt5a signal governs astrogliosis during HIV-associated pain pathogenesis.

Chronic pain is the most common neurological disorder of HIV patients. Multiple neuropathologies were identified in the pain pathway. Among them is the prominent astrocytic reaction (also know an astrogliosis). However, the pathogenic role and mechanism of the astrogliosis are unclear. Here, we show that the astrogliosis is crucial for the pain development induced by a key neurotoxic HIV protein gp120 and that a neuron-to-astrocyte Wnt5a signal controls the astrogliosis. Ablation of astrogliosis blocked the development of gp120-induced mechanical hyperalgesia, and concomitantly the expression of neural circuit polarization in the spinal dorsal horn. We demonstrated that conditional knockout of either Wnt5a in neurons or its receptor ROR2 in astrocytes abolished not only gp120-induced astrogliosis but also hyperalgesia and neural circuit polarization. Furthermore, we found that the astrogliosis promoted expression of hyperalgesia and NCP via IL-1ß regulated by a Wnt5a-ROR2-MMP2 axis. Our results shed light on the role and mechanism of astrogliosis in the pathogenesis of HIV-associated pain.

Ethnic/Racial Disparities in Longitudinal Neurocognitive Decline in People With HIV.

BACKGROUND: To examine longitudinal neurocognitive decline among Latino, non-Latino Black, and non-Latino White people with HIV (PWH) and factors that may explain ethnic/racial disparities in neurocognitive decline. METHODS: Four hundred ninety nine PWH (13.8% Latino, 42.7% Black, 43.5% White; baseline age: M = 43.5) from the CNS HIV Anti-Retroviral Therapy Effects Research (CHARTER) study completed neurocognitive, neuromedical, and laboratory assessments every 6-12 months with up to 5 years of follow-up. Longitudinal neurocognitive change was determined via published regression-based norms. Survival analyses investigated the relationship between ethnicity/race and neurocognitive change, and baseline and time-dependent variables that may explain ethnic/racial disparities in neurocognitive decline, including socio-demographic, HIV-disease, medical, psychiatric, and substance use characteristics. RESULTS: In Cox proportional hazard models, hazard ratios for neurocognitive decline were increased for Latino compared with White PWH (HR = 2.25, 95% CI = 1.35 to 3.73, P = 0.002), and Latino compared with Black PWH (HR = 1.86, 95% CI = 1.14 to 3.04, P = 0.013), with no significant differences between Black and White PWH (P = 0.40). Comorbidities, including cardiometabolic factors and more severe neurocognitive comorbidity classification, accounted for 33.6% of the excess hazard for Latino compared with White PWH, decreasing the hazard ratio associated with Latino ethnicity (HR = 1.83, 95% CI = 1.06 to 3.16, P = 0.03), but did not fully account for elevated risk of decline. CONCLUSIONS: Latino PWH may be at higher risk of early neurocognitive decline compared with Black and White PWH. Comorbidities accounted for some, but not all, of this increased risk among Latino PWH. Future research examining institutional, sociocultural, and biomedical factors, including structural discrimination and age-related biomarkers, may further explain the observed disparities.

Lentiviral Infections Persist in Brain despite Effective Antiretroviral Therapy and Neuroimmune Activation.

HIV infection persists in different tissue reservoirs among people with HIV (PWH) despite effective antiretroviral therapy (ART). In the brain, lentiviruses replicate principally in microglia and trafficking macrophages. The impact of ART on this viral reservoir is unknown. We investigated the activity of contemporary ART in various models of lentivirus brain infection. HIV-1 RNA and total and integrated DNA were detected in cerebral cortex from all PWH (n = 15), regardless of ART duration or concurrent plasma viral quantity and, interestingly, integrated proviral DNA levels in brain were significantly higher in the aviremic ART-treated group (P < 0.005). Most ART drugs tested (dolutegravir, ritonavir, raltegravir, and emtricitabine) displayed significantly lower 50% effective concentration (EC50) values in lymphocytes than in microglia, except tenofovir, which showed 1.5-fold greater activity in microglia (P < 0.05). In SIV-infected Chinese rhesus macaques, despite receiving suppressive (n = 7) or interrupted (n = 8) ART, brain tissues had similar SIV-encoded RNA and total and integrated DNA levels compared to brains from infected animals without ART (n = 3). SIV and HIV-1 capsid antigens were immunodetected in brain, principally in microglia/macrophages, regardless of ART duration and outcome. Antiviral immune responses were comparable in the brains of ART-treated and untreated HIV- and SIV-infected hosts. Both HIV-1 and SIV persist in brain tissues despite contemporary ART, with undetectable virus in blood. ART interruption exerted minimal effect on the SIV brain reservoir and did not alter the neuroimmune response profile. These studies underscore the importance of augmenting ART potency in different tissue compartments. IMPORTANCE Antiretroviral therapy (ART) suppresses HIV-1 in plasma and CSF to undetectable levels. However, the impact of contemporary ART on HIV-1 brain reservoirs remains uncertain. An active viral reservoir in the brain during ART could lead to rebound systemic infection after cessation of therapy, development of drug resistance mutations, and neurological disease. ART's impact, including its interruption, on brain proviral DNA remains unclear. The present studies show that in different experimental platforms, contemporary ART did not suppress viral burden in the brain, regardless of ART component regimen, the duration of therapy, and its interruption. Thus, new strategies for effective HIV-1 suppression in the brain are imperative to achieve sustained HIV suppression.

Predictors of Transition to Frailty in Middle-Aged and Older People With HIV: A Prospective Cohort Study.

BACKGROUND: People with HIV (PWH) have increased frailty risk at younger ages compared with the general population. Multimorbidity is associated with frailty, yet effects of specific comorbidities on transition to frailty in PWH are unknown. SETTING: Prospective study of 219 PWH age 45 years or older in the National NeuroAIDS Tissue Consortium. METHODS: Frailty status was categorized using Fried frailty phenotype criteria. Comorbidities [bone disease, cardiovascular disease, cerebrovascular disease, liver disease, renal disease, diabetes, chronic obstructive pulmonary disease (COPD), hypertension, obesity, cancers, neuropsychiatric conditions] were assessed from longitudinal data. Associations between baseline comorbidities and transition to frailty within 30 months were analyzed using Kaplan-Meier and Cox regression models. Grip strength was assessed using mixed-effects models. RESULTS: At baseline, the median age was 61 years, 73% were male 98% were on antiretroviral therapy, 29% had ≥3 comorbidities, 27% were robust, and 73% were pre-frail. Cerebrovascular disease, diabetes, and COPD were independent predictors of transition to frailty within 30 months in models adjusted for age, sex, and multimorbidity (≥3 additional comorbidities) [hazard ratios (95% confidence intervals) 2.52 (1.29 to 4.93), 2.31 (1.12 to 4.76), and 1.82 (0.95 to 3.48), respectively]. Furthermore, cerebrovascular disease, diabetes, COPD, or liver disease co-occurring with multimorbidity was associated with substantially increased frailty hazards compared with multimorbidity alone (hazard ratios 4.75-7.46). Cerebrovascular disease was associated with decreased baseline grip strength (P = 0.0001), whereas multimorbidity, diabetes, and COPD were associated with declining grip strength (P < 0.10). CONCLUSIONS: In older PWH, cerebrovascular disease, diabetes, COPD, or liver disease co-occurring with multimorbidity is associated with substantially increased risk of becoming frail within 30 months. Interventions targeting these comorbidities may ameliorate frailty and age-related functional decline in PWH.

Multimorbidity networks associated with frailty among middle-aged and older people with HIV.

OBJECTIVE: People with HIV (PWH) have increased prevalence of multimorbidity and frailty at younger ages compared with the general population. This study investigated individual and combinatorial effects of neuropsychiatric and medical comorbidities as predictors of frailty in PWH. DESIGN: Analysis of data from the National NeuroAIDS Tissue Consortium, a longitudinal observational cohort. METHODS: Five hundred and twenty-four PWH over age 40 years were classified using Fried's Frailty criteria. Twelve comorbidities were documented from longitudinal data and associations between individual and co-occurring comorbidities with frailty were assessed using weighted network and logistic regression analyses. RESULTS: At frailty assessment between 2015 and 2020, median age was 61 years, 76% were men, 94% were on antiretroviral therapy (ART), 73% had two or more comorbidities, 24% were frail, and 52% were prefrail. Among individual comorbidities, highest odds of frailty were in participants with depressive symptoms [adjusted odds ratio (aOR), 95% confidence interval (CI) 3.48 (2.22-5.46)], followed by bone disease and chronic obstructive pulmonary disease (COPD) [2.47 (1.28-4.72) and 2.13 (1.36-3.34), respectively]. Among co-occurring comorbidities, highest odds of frailty were in participants having depressive symptoms with diabetes, hypertension, or obesity [aORs (95% CIs) 5.29 (2.32-12.08), 5.21 (2.65-10.40), 4.85 (2.39-9.95), respectively], cognitive impairment with diabetes or renal disease [2.81 (1.38-5.68) and 2.53 (1.26-5.03), respectively], renal disease with cardiovascular disease [2.81 (1.32-6.01)], and diabetes with obesity [2.76 (1.39-5.45)]. CONCLUSION: Co-occurrence of depressive symptoms, cognitive impairment, diabetes, or renal disease with other medical conditions substantially increases odds of frailty in older PWH. Identifying and treating these comorbidities may help to reduce functional decline with aging in PWH.

Novel Role for Macrophage Galactose-Type Lectin-1 to Regulate Innate Immunity against Mycobacterium tuberculosis.

Tuberculosis (TB) caused by infection with Mycobacterium tuberculosis is characterized by inflammatory pathology and poorly understood mechanisms of innate immunity. Pattern recognition receptors, expressed on the surface of macrophages, determine the balance of inflammatory and antimicrobial functions that influence disease outcome. Carbohydrate moieties displayed by mycobacteria can serve as pattern recognition receptor ligands for some members of the C-type lectin receptor (CLR) family, interactions that mediate a variety of incompletely understood immune outcomes. This work identifies a novel role for the CLR macrophage galactose-type lectin (MGL)-1 in a mouse model (C57BL/6 and MGL-1-/-) of experimental TB. Murine macrophages upregulated MGL-1 following in vitro exposure to M. tuberculosis, whereas MGL+ cells accumulated at sites of mycobacteria-driven inflammation in the lung. Pulmonary macrophages from MGL-1-deficient mice displayed increased production of proinflammatory cytokines (IL-1ß, IL-6, and IFN-γ) that were associated with greater lipid accumulation, following M. tuberculosis infection. Surprisingly, for a CLR, we also observed MGL-1-dependent antimycobacterial activity as evidenced by greater M. tuberculosis proliferation in bone marrow-derived macrophages, and the lung, of MGL-1-deficient mice. Differential transcriptome analysis further revealed that loss of MGL-1 perturbs the activation of various genes involved in the regulation of inflammation and lipid metabolism in the setting of M. tuberculosis infection. These results identify MGL-1 signaling as an important mechanism that regulates innate immunity against M. tuberculosis and indicates the potential for the MGL pathway as a novel therapeutic target for anti-TB immunity.