Probing the Interface of HIV and Inflammaging

GNLY+CD8+ T cells bridge premature aging and persistent inflammation in people living with HIV

People living with HIV (PLWH) exhibit accelerated aging, characterized by systemic inflammation, termed "inflammaging." While T-cell expansion is prevalent in PLWH, its connection to inflammaging remains unclear. In this study, we analyzed the TCRβ repertoire of 257 healthy controls (HC) and 228 PLWH, revealing pronounced T cell clonal expansion in PLWH. The expansion was only partially reversed following antiretroviral therapy (ART) and closely associated with ART duration, CD4+ T and CD8+ T cell counts and the CD4/CD8 ratio. TCR-based age modeling showed a continuous accelerated trajectory of aging in PLWH, especially in younger individuals, in stark contrast to the nonlinear aging acceleration pattern seen in HC. Furthermore, using single-cell RNA combined TCR sequencing and in vitro experiments, we identified GNLY+CD8+ T cells as the primary population driving clonal expansion and maintenance in PLWH. These cells are characterized by high cytotoxicity and low exhaustion and are activated by interleukin-15 (IL-15) in vitro. Notably, GNLY+CD8+ T cells predominantly express the pro-inflammatory 15 kDa form of granulysin(GNLY). The supernatant from IL-15-stimulated CD8+ T cells induces monocytes to secrete inflammatory factors and disrupts the integrity of intestinal epithelial cells, which can be partially restored by the anti-GNLY antibodies. These findings identify GNLY+CD8+ T cells as the central drivers of persistent clonal expansion, highlighting their crucial role for mitigating inflammaging in PLWH.

Treatment of Advanced HIV in the Modern Era

Antiretroviral therapy has transformed human immunodeficiency virus (HIV) infection from a fatal illness into a manageable chronic condition. However, despite remarkable progress, the HIV epidemic remains a global health challenge, with ambitious targets such as 95-95-95 by 2030 at risk of being unmet. While antiretroviral therapy availability has expanded worldwide, gaps persist, including unawareness of HIV status, inconsistent medication uptake, and limited engagement in care across diverse settings. Advanced HIV represents a particularly challenging yet underexplored aspect of HIV care. Its definition is complex, complicating efforts to address the needs of this vulnerable population. This review characterizes advanced HIV populations, defines them by spectra of immune suppression, antiretroviral therapy exposure, and drug resistance, and explores contemporary approaches to their management, with a particular focus on drug resistance and its clinical implications in modern HIV care. It highlights the unique challenges faced by individuals presenting late to care, those with limited care engagement, and aging populations with long-term exposure to HIV and antiretroviral therapy. By defining these populations, refining our understanding of advanced HIV, and addressing the diverse needs of affected individuals, providers can enhance outcomes and develop strategies to overcome barriers to care. Bridging these critical gaps is essential to advancing global efforts to end the HIV epidemic, both in the USA and worldwide.

Biomarkers of microbial translocation and generalized inflammation are associated with frailty among people with HIV

BACKGROUND

Frailty occurs at higher rates and younger ages among people with HIV (PWH) compared with the general population and is often attributed to chronic inflammation and subsequent immune exhaustion. We assessed how inflammatory biomarkers are associated with frailty among PWH.

METHODS

The Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems (CNICS) cohort is comprised of adult PWH in care at 10 sites, and harmonizes demographic, clinical, and patient-reported outcomes (PRO) data. A panel of 13 inflammatory biomarkers was collected from a subset of virally suppressed PWH once per person between 2010 and 2018. Frailty was measured with a validated PRO phenotype, scored 0-4, from biomarker collection date through July 2022. With adjusted linear mixed models, we estimated longitudinal associations between standard deviation-scaled log 2 -transformed biomarkers and frailty score.

RESULTS

Among 273 PWH, most were men (91%), average age at baseline was 45, 42% were non-Hispanic White whereas 35% were non-Hispanic Black, and average follow-up time was 5.5 years. Several biomarkers were associated with higher frailty, including those linked to microbial translocation (sCD14, LBP, KT ratio) and systemic inflammation (CRP, IL-6, suPAR, sTNFR1, sTNFR2). Higher IL-6 was associated with a 0.25-point higher frailty score [95% confidence interval (CI) 0.12-0.39]. Higher sTNFR1 [0.35 (0.13-0.56)], sCD14 [0.21 (0.11-0.31)], and suPAR [0.24 (0.11-0.36)] levels were also associated with higher frailty scores over follow-up.

CONCLUSION

Higher levels of biomarkers linked to microbial translocation and systemic inflammation are associated with higher average frailty scores over time in a cohort of virally suppressed PWH, highlighting these pathways as potential interventional targets for mitigating frailty in PWH.

Cytokine trajectory over time in men and women with HIV on long-term antiretroviral therapy

OBJECTIVE

Although antiretroviral therapy (ART) suppresses viral replication and reduces inflammation, it does not lead to the normalization of cytokines. The long-term effects of ART beyond viral suppression have not been studied and are mostly limited to cross-sectional research.

DESIGN

The impact of long-term ART on the trajectory of 40 cytokines/chemokines in 31 men and 59 women who maintained viral suppression over a median period of 6 years (317 visits ranging from 24 to 384 weeks post ART initiation) were measured by Luminex.

METHODS

We used a generalized additive model with a Gaussian distribution and identity link function to model concentrations over time and investigate sex and race differences.

RESULTS

While most cytokine/chemokine trajectories remained stable, the trajectory of nine markers of monocyte/macrophage activation (IP-10, I-TAC, MIG, sCD163, sCD14, MCP-1, MIP-3β, CXCL13, TNF-α) decreased over time (adj. P < 0.05). Despite continuous viral suppression, M-CSF, IL-15, and LBP increased over time (adj. P < 0.05). sCD14 was the only cytokine whose trajectory differed by sex (adj. P = 0.033). Overall, women had lower mean levels of IL-18 but higher levels of sCD14 than did men (adj. P < 0.05). GROα, LBP, and sCD14 showed significant differences between races (adj. P < 0.05). No association between cytokines and cellular HIV DNA/RNA was found.

CONCLUSION

Our study reveals a continuous decline in markers of monocyte/macrophage activation over 6 years of suppressive ART, indicating that long-term treatment may mitigate inflammaging and cardiovascular-related outcomes. The higher levels of sCD14 observed in women are consistent with them having greater innate immune activation than men do.

Knowledge, attitudes and practices in HIV-related chronic inflammation and cardiovascular risk in Spain

BACKGROUND

People with HIV (PWH) in suppressive antiretroviral treatment suffer from chronic inflammation-related comorbidities, mainly cardiovascular diseases. However, given the lack of specific evidence about inflammation in PWH, clinical guidelines do not provide recommendations for the management of this issue. To date, physician awareness of inflammation in PWH remains unclear. We analyzed the knowledge, attitudes, and practices (KAP) related to inflammation, particularly in the clinical management of PWH, of infectious disease specialists (IDS)/internists compared to other specialists treating inflammation directly (rheumatologists) or its cardiovascular consequences (cardiologists).

METHODS

A committee of IDS/internists treating PWH, cardiologists, and rheumatologists designed the KAP questionnaire. The survey was completed by 405 participants (135 physicians per specialty) stratified by Spanish geography, hospital size, and number of PWH under care (IDS/internists only).

RESULTS

IDS/internists treating PWH scored higher than cardiologists and rheumatologists on knowledge of inflammation (5.5±1.4 out of 8 points vs. 5.2±1.3 and 4.6±1.4 points, respectively; p<0.05). Nevertheless, rheumatologists showed the most proactive attitude toward inflammation (i.e., biomarkers monitoring, anti-inflammatory drug prescription and cardiologist referral), followed by cardiologists and IDS/internists (13±3 of a total of 16 points vs. 11±3 and 10±3.3 points, respectively; p<0.05), irrespective of hospital size and years of experience. Most IDS/internists (59%) include inflammation in their therapeutic recommendations. However, in IDS/internists treating PWH, we observed a negative correlation between years of experience and concern about the clinical consequences of inflammation.

CONCLUSION

Our findings show that, compared to other specialists, infectious disease specialists/internists have high knowledge about inflammation in HIV infection, but, in the absence of scientific evidence to base their decisions on inflammatory markers, the therapeutic implications are scarce. The results support the need for more evidence on the monitoring and treatment of inflammation in PWH.

The impacts of tobacco and nicotine on HIV-1 infection, inflammation, and the blood-brain barrier in the central nervous system

Human immunodeficiency virus (HIV-1) remains a persistent global health crisis. Even while successfully virologically suppressed, people with HIV (PWH) experience a higher risk for inflammatory disorders such as HIV-associated neurocognitive disorder (HAND). Tobacco use puts PWH at higher risk for neurocognitive symptoms resulting from HIV-associated neuroinflammation. The NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome has been implicated as a driver of HIV-associated inflammation, including HAND. Nicotine, the psychoactive component of tobacco smoke, has also been shown to signal through the NLRP3 inflammasome and modulate inflammatory signaling in the CNS. Here, we explore the impacts of nicotine and tobacco on the complex neurobiology of HAND, including effects on cognition, inflammation, viral latency, and blood-brain barrier integrity. We outline nicotine's role in the establishment of active and latent infection in the brain and posit the NLRP3 inflammasome as a common pathway by which HIV-1 and nicotine promote neuroinflammation in PWH.

HLA-C*07 is associated with symptomatic HIV-1-associated neurocognitive disorders (HAND) and immune dysregulation

BACKGROUND

HIV-1-associated neurocognitive disorders (HAND) in stable patients undergoing antiretroviral therapy (ART) may result from ongoing immune dysregulation and chronic inflammation. A contributing factor may result from the unstable HLA class I allele, HLA-C*07.

OBJECTIVE

To assess the genetic profile of killer-cell immunoglobulin-like receptors (KIR), human leukocyte antigens (HLA), and immune activation or senescence markers and their association with HAND in stable HIV-1 patients receiving ART.

METHODS

An observational cross-sectional study was carried out with 96 patients with asymptomatic or symptomatic HAND. HLA and KIR as well as immune activation/senescence biomarkers in peripheral blood cells were assessed by SSO-Luminex typing and flow cytometry, respectively.

RESULTS

HLA-C*07 is associated with symptomatic HAND. The frequency of two copies of HLA-C*07 was higher in patients with symptomatic than with asymptomatic HAND (12.0 vs. 2.2%, ρ < 0.001). The percentage of senescent CD8+CD28- T-cells was higher in patients with two copies of HLA-C*07 (ρ < 0.05). In patients with symptomatic HAND, the percentages of non-senescent CD8+CD28+ T cells were inversely proportional to the number of copies of the HLA-C*07 (ρ < 0.05).

CONCLUSION

Patients with symptomatic HAND showed a higher frequency of the homozygotic unstable HLA-C*07 allotype, which could be associated with neurocognitive complications. Two copies of HLA-C*07 were associated with immune senescent T lymphocyte profiles characterized by the loss of CD28 expression.

A Perfect Storm: The Convergence of Aging, Human Immunodeficiency Virus Infection, and Inflammasome Dysregulation

The emergence of combination antiretroviral therapy (cART) has greatly transformed the life expectancy of people living with HIV (PWH). Today, over 76% of the individuals with HIV have access to this life-saving therapy. However, this progress has come with a new challenge: an increase in age-related non-AIDS conditions among patients with HIV. These conditions manifest earlier in PWH than in uninfected individuals, accelerating the aging process. Like PWH, the uninfected aging population experiences immunosenescence marked by an increased proinflammatory environment. This phenomenon is linked to chronic inflammation, driven in part by cellular structures called inflammasomes. Inflammatory signaling pathways activated by HIV-1 infection play a key role in inflammasome formation, suggesting a crucial link between HIV and a chronic inflammatory state. This review outlines the inflammatory processes triggered by HIV-1 infection and aging, with a focus on the inflammasomes. This review also explores current research regarding inflammasomes and potential strategies for targeting inflammasomes to mitigate inflammation. Further research on inflammasome signaling presents a unique opportunity to develop targeted interventions and innovative therapeutic modalities for combating HIV and aging-associated inflammatory processes.

Accelerated aging in people living with HIV: The neuroimmune feedback model

People living with HIV (PLWH) experience earlier onset of aging-related comorbidities compared to their counterparts without HIV. This paper lays out a theoretical model to explain why PLWH experience accelerated aging. Briefly, the model is structured as follows. PLWH experience disproportionately heavy burdens of psychosocial stress across the life course. This psychosocial stress increases risks for depressive symptoms and problematic substance use. Depressive symptoms and problematic substance use interfere with long-term adherence to antiretroviral therapy (ART). Lower ART adherence, in turn, exacerbates the elevated systemic inflammation stemming from HIV infection. This inflammation increases risks for aging-related comorbidities. Systemic inflammation also reduces connectivity in the brain's central executive network (CEN), a large-scale brain network that is critical for coping with stressful circumstances. This reduced capacity for coping with stress leads to further increases in depressive symptoms and problematic substance use. Together, these changes form a neuroimmune feedback loop that amplifies the impact of psychosocial stress on aging-related comorbidities. In this paper, I review the existing evidence relevant to this model and highlight directions for future research.

HIV-1 infection of genetically engineered iPSC-derived central nervous system-engrafted microglia in a humanized mouse model

IMPORTANCE

Our mouse model is a powerful tool for investigating the genetic mechanisms governing central nervous system (CNS) human immunodeficiency virus type-1 (HIV-1) infection and latency in the CNS at a single-cell level. A major advantage of our model is that it uses induced pluripotent stem cell-derived microglia, which enables human genetics, including gene function and therapeutic gene manipulation, to be explored in vivo, which is more challenging to study with current hematopoietic stem cell-based models for neuroHIV. Our transgenic tracing of xenografted human cells will provide a quantitative medium to develop new molecular and epigenetic strategies for reducing the HIV-1 latent reservoir and to test the impact of therapeutic inflammation-targeting drug interventions on CNS HIV-1 latency.

Drawing the Line Between Postacute Sequelae of COVID-19 and Functional Neurologic Disorders: A Daunting Clinical Overlap or Irrelevant Conundrum?

ABSTRACT

Coronavirus disease 2019 (COVID-19) is an acute infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in its multiple variants that classically presents with cough, fatigue, fever, headache, myalgias, and diarrhea. As vaccination becomes widely available and infection rates facilitate herd immunity across the globe, more attention has been given to long-term symptoms that may persist after the index infection, which include impairments in concentration, executive dysfunction, sensory disturbances, depression, anxiety, fatigue, and cough, among other symptoms classified under the umbrella term of postacute sequelae of SARS-CoV-2 infection (PASC).Functional neurologic disorder (FND), also known as conversion disorder and functional neurologic symptom disorder, refers to the presence of one or more symptoms of altered voluntary motor or sensory function that are incompatible with and not better explained by a known neurological or medical condition that causes significant distress and functional impairment. Although the diagnosis of FND may not require the identification of an underlying psychological stressor, being diagnosed with an FND can worsen stigma and shift attention and resources away from other medical concerns that should be concomitantly addressed.This review summarizes the literature on the overlapping nature and discrimination of PASC from FND in COVID-19 survivors. Based on this, we develop a treatment framework that targets unique domains of these complex overlapping presentations, following a multidisciplinary approach with an individualized treatment plan inclusive of physical and psychological interventions focused on functional rehabilitation.

Health and sociodemographic factors associated with low muscle strength, muscle mass, and physical performance among people living with HIV

ABSTRACTThis study examined the factors associated with low muscle strength, muscle mass, and physical performance in 331 people living with HIV. Participants completed handgrip as a strength measure, appendicular skeletal muscle mass using bioimpedance analysis, and chair rise was a physical performance measure. Multivariate logistic regression was used to analyze the association between low values on these measures with sociodemographic, HIV-related factors, and comorbidities. Higher body mass index (BMI) (OR = 0.91; CI = 0.86-0.97) and higher CD4/CD8 ratio (OR = 0.38; 95% CI = 0.18-0.82) were associated with decreased likelihood of low handgrip strength. Being non-employed (OR = 2.08; 95% CI = 1.07-4.06), having hypertension (OR = 2.27; 95% CI = 1.13-4.54) and rheumatism (OR = 5.46; 95% CI = 1.68-17.74) increased the chance of low handgrip strength. Higher BMI (OR = 0.43; 95% CI = 0.34-0.56), CD4/CD8 ratio (OR = 0.29; 95% CI = 0.09-0.93), and bioimpedance phase angle (OR = 0.22; 95% CI = 0.12-0.40) were associated with decreased likelihood of low muscle mass. Lastly, having less than eight years of education (OR = 1.87; 95% CI = 1.02-3.41) and being non-employed (OR = 8.18; 95% CI = 3.09-21.61) increased the chance of low chair stand performance. In addition, higher CD4 + lymphocytes count (OR = 0.99; 95% CI = 0.99-0.99) was associated with a decreased likelihood of low chair stand performance. In conclusion, specific and non-specific HIV-related factors are associated with low handgrip strength, low muscle mass, and/or low chair stand performance.

The role of TEMRA cell-mediated immune senescence in the development and treatment of HIV disease

Human Immunodeficiency Virus (HIV) has plagued human society for a long time since its discovery, causing a large number of patients to suffer and costing hundreds of millions of medical services every year. Scientists have found that HIV and antiretroviral therapy accelerate immune aging by inducing mitochondrial dysfunction, and that terminal effector memory T cells (TEMRA cells) are crucial in immune aging. This specific subset of effector memory T cells has terminally differentiated properties and exhibits high cytotoxicity and proinflammatory capacity. We therefore explored and described the interplay between exhaustion features, essential markers, functions, and signaling pathways from previous studies on HIV, antiretroviral therapy, immune senescence, and TEMRA cells. Their remarkable antiviral capacity is then highlighted by elucidating phenotypic changes in TEMRA cells during HIV infection, describing changes in TEMRA cells before, during, and after antiretroviral therapy and other drug treatments. Their critical role in complications and cytomegalovirus (CMV)-HIV superinfection is highlighted. These studies demonstrate that TEMRA cells play a key role in the antiviral response and immune senescence during HIV infection. Finally, we review current therapeutic strategies targeting TEMRA cells that may be clinically beneficial, highlight their potential role in HIV-1 vaccine development, and provide perspectives and predictions for related future applications.

An Overview of Miami CDEIPI and a Showcase of Team Science and Cutting-Edge Research Driven by Students

BACKGROUND

The Miami-CFAR Diversity, Equity & Inclusion Pathway Initiative (Miami CDEIPI) is designed to promote a diverse scientific workforce that reflects the communities at the highest risk of HIV in South Florida.

SETTING AND METHODS

The focus of the Miami CDEIPI is to help train the next generation of Underrepresented Minorities (URM) and Black, Indigenous, People of Color (BIPOC) in HIV/AIDS-related research through a team science experience. The Miami CDEIPI objectives are to facilitate the interaction of URM/BIPOC students with the network of CFAR-affiliated investigators and to enable these students to access the cutting-edge technologies at the Miami-CFAR and the Sylvester Comprehensive Cancer Center and other resources at the University of Miami.

RESULTS

Five URM/BIPOC students supported by the program in year 1 have been carrying out projects in collaboration with mentors at their parent institution and Miami-CFAR investigators. The students used the state-of-the-art laboratories and core facilities. They began their research with a proposal designed to integrate the cutting-edge technologies now available to them. Their training included participation in Miami-CFAR-sponsored activities such as seminars, an annual conference, and a national HIV workshop. Candidates in the Miami CDEIPI are in the process of developing their research proposals, integrating cutting-edge technologies into their doctoral dissertation research. Their projects are now in the completion phase.

CONCLUSIONS

The Miami CDEIPI focuses its resources on one of the conspicuous gaps in the career paths of URM/BIPOC researchers-the dearth of leading URM/BIPOC scientists in the field. The Miami CDEIPI provides a professional network that supports the participation of URM/BIPOC trainees in innovative research and career skill training.

Antibody neutralization capacity after coronavirus disease 2019 vaccination in people with HIV in Canada

OBJECTIVES

Many vaccines require higher/additional doses or adjuvants to provide adequate protection for people with HIV (PWH). Here, we compare coronavirus disease 2019 (COVID-19) vaccine-induced antibody neutralization capacity in PWH vs. HIV-negative individuals following two vaccine doses.

DESIGN

In Canadian prospective observational cohorts, including a multicentre study of PWH receiving at least two COVID-19 vaccinations (mRNA or ChAdOx1-S), and a parallel study of HIV-negative controls (Stop the Spread Ottawa Cohort), we measured vaccine-induced neutralization capacity 3 months post dose 2 (±1 month).

METHODS

COVID-19 neutralization efficiency was measured by calculating the half maximal inhibitory dilution (ID50) using a high-throughput protein-based neutralization assay for Ancestral (Wuhan), Delta and Omicron (BA.1) spike variants. Univariable and multivariable quantile regression were used to compare COVID-19-specific antibody neutralization capacity by HIV status.

RESULTS

Neutralization assays were performed on 256 PWH and 256 controls based on specimen availability at the timepoint of interest, having received two vaccines and known date of vaccination. There was a significant interaction between HIV status and previous COVID-19 infection status in median ID50. There were no differences in median ID50 for HIV+ vs. HIV-negative persons without past COVID-19 infection. For participants with past COVID-19 infection, median ICD50 was significantly higher in controls than in PWH for ancestral SARS-CoV-2 and Omicron variants, with a trend for the Delta variant in the same direction.

CONCLUSION

Vaccine-induced SARS-CoV-2 neutralization capacity was similar between PWH vs. HIV-negative persons without past COVID-19 infection, demonstrating favourable humoral-mediated immunogenicity. Both HIV+ and HIV-negative persons demonstrated hybrid immunity.

TRIAL REGISTRATION

clinicaltrials.gov NCT04894448.

Management of Type 2 Diabetes Mellitus and Kidney Failure in People with HIV-Infection in Africa: Current Status and a Call to Action

There is an increasing global burden of diabetes mellitus (DM) and chronic kidney disease (CKD), coupled with a high burden of people with HIV (PWH). Due to an increased lifespan on ART, PWH are now at risk of developing non-communicable diseases, including DM. Africa has the greatest burden of HIV infection and will experience the greatest increase in prevalence of DM over the next two decades. In addition, there is a rising number of people with CKD and progression to kidney failure. Therefore, there is an urgent need for the early identification and management of all 3 diseases to prevent disease progression and complications. This is particularly important in Africa for people with CKD where there is restricted or no access to dialysis and/or transplantation. This review focuses on the epidemiology and pathophysiology of the interaction between HIV infection and DM and the impact that these diseases have on the development and progression of CKD. Finally, it also aims to review the data on the management, which stems from the growing burden of all three diseases.

HIV, asymptomatic STI, and the rectal mucosal immune environment among young men who have sex with men

Young men who have sex with men (YMSM) are disproportionately affected by HIV and bacterial sexually transmitted infections (STI) including gonorrhea, chlamydia, and syphilis; yet research into the immunologic effects of these infections is typically pursued in siloes. Here, we employed a syndemic approach to understand potential interactions of these infections on the rectal mucosal immune environment among YMSM. We enrolled YMSM aged 18-29 years with and without HIV and/or asymptomatic bacterial STI and collected blood, rectal secretions, and rectal tissue biopsies. YMSM with HIV were on suppressive antiretroviral therapy (ART) with preserved blood CD4 cell counts. We defined 7 innate and 19 adaptive immune cell subsets by flow cytometry, the rectal mucosal transcriptome by RNAseq, and the rectal mucosal microbiome by 16S rRNA sequencing and examined the effects of HIV and STI and their interactions. We measured tissue HIV RNA viral loads among YMSM with HIV and HIV replication in rectal explant challenge experiments among YMSM without HIV. HIV, but not asymptomatic STI, was associated with profound alterations in the cellular composition of the rectal mucosa. We did not detect a difference in the microbiome composition associated with HIV, but asymptomatic bacterial STI was associated with a higher probability of presence of potentially pathogenic taxa. When examining the rectal mucosal transcriptome, there was evidence of statistical interaction; asymptomatic bacterial STI was associated with upregulation of numerous inflammatory genes and enrichment for immune response pathways among YMSM with HIV, but not YMSM without HIV. Asymptomatic bacterial STI was not associated with differences in tissue HIV RNA viral loads or in HIV replication in explant challenge experiments. Our results suggest that asymptomatic bacterial STI may contribute to inflammation particularly among YMSM with HIV, and that future research should examine potential harms and interventions to reduce the health impact of these syndemic infections.

HIV-1 infection of genetically engineered iPSC-derived central nervous system-engrafted microglia in a humanized mouse model

The central nervous system (CNS) is a major human immunodeficiency virus type 1 reservoir. Microglia are the primary target cell of HIV-1 infection in the CNS. Current models have not allowed the precise molecular pathways of acute and chronic CNS microglial infection to be tested with in vivo genetic methods. Here, we describe a novel humanized mouse model utilizing human-induced pluripotent stem cell-derived microglia to xenograft into murine hosts. These mice are additionally engrafted with human peripheral blood mononuclear cells that served as a medium to establish a peripheral infection that then spread to the CNS microglia xenograft, modeling a trans-blood-brain barrier route of acute CNS HIV-1 infection with human target cells. The approach is compatible with iPSC genetic engineering, including inserting targeted transgenic reporter cassettes to track the xenografted human cells, enabling the testing of novel treatment and viral tracking strategies in a comparatively simple and cost-effective way vivo model for neuroHIV.

The impact of cannabinoids on inflammasome signaling in HIV-1 infection

Human immunodeficiency virus type 1 (HIV-1) is a chronic disease that afflicts over 38 million people worldwide without a known cure. The advent of effective antiretroviral therapies (ART) has significantly decreased the morbidity and mortality associated with HIV-1 infection in people living with HIV-1 (PWH), thanks to durable virologic suppression. Despite this, people with HIV-1 experience chronic inflammation associated with co-morbidities. While no single known mechanism accounts for chronic inflammation, there is significant evidence to support the role of the NLRP3 inflammasome as a key driver. Numerous studies have demonstrated therapeutic impact of cannabinoids, including exerting modulatory effects on the NLRP3 inflammasome. Given the high rates of cannabinoid use in PWH, it is of great interest to understand the intersecting biology of the role of cannabinoids in HIV-1-associated inflammasome signaling. Here we describe the literature of chronic inflammation in people with HIV, the therapeutic impact of cannabinoids in PWH, endocannabinoids in inflammation, and HIV-1-associated inflammation. We describe a key interaction between cannabinoids, the NLRP3 inflammasome, and HIV-1 viral infection, which supports further investigation of the critical role of cannabinoids in HIV-1 infection and inflammasome signaling.

Inflammasomes as mediators of inflammation in HIV-1 infection

Human immunodeficiency virus type 1 (HIV-1) infection is a chronic disease without a known cure. The advent of effective antiretroviral therapy (ART) has enabled people with HIV (PWH) to have significantly prolonged life expectancies. As a result, morbidity and mortality associated with HIV-1 infection have declined considerably. However, these individuals experience chronic systemic inflammation whose multifaceted etiology is associated with other numerous comorbidities. Inflammasomes are vital mediators that contribute to inflammatory signaling in HIV-1 infection. Here, we provide an overview of the inflammatory pathway that underlies HIV-1 infection, explicitly highlighting the role of the NLRP3 inflammasome. We also delineate the current literature on inflammasomes and the therapeutic targeting strategies aimed at the NLRP3 inflammasome to moderate HIV-1 infection-associated inflammation. Here we describe the NLRP3 inflammasome as a key pathway in developing novel therapeutic targets to block HIV-1 replication and HIV-1-associated inflammatory signaling. Controlling the inflammatory pathways is critical in alleviating the morbidities and mortality associated with chronic HIV-1 infection in PWH.

Systemic cytokines and GlycA discriminate disease status and predict corticosteroid response in HTLV-1-associated neuroinflammation

BACKGROUND

HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) is an incapacitating neuroinflammatory disorder for which no disease-modifying therapy is available, but corticosteroids provide some clinical benefit. Although HAM/TSP pathogenesis is not fully elucidated, older age, female sex and higher proviral load are established risk factors. We investigated systemic cytokines and a novel chronic inflammatory marker, GlycA, as possible biomarkers of immunopathogenesis and therapeutic response in HAM/TSP, and examined their interaction with established risk factors.

PATIENTS AND METHODS

We recruited 110 People living with HTLV-1 (PLHTLV-1, 67 asymptomatic individuals and 43 HAM/TSP patients) with a total of 946 person-years of clinical follow-up. Plasma cytokine levels (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, TNF) and GlycA were quantified by Cytometric Bead Array and 1NMR, respectively. Cytokine signaling and prednisolone response were validated in an independent cohort by nCounter digital transcriptomics. We used multivariable regression, machine learning algorithms and Bayesian network learning for biomarker identification.

RESULTS

We found that systemic IL-6 was positively correlated with both age (r = 0.50, p < 0.001) and GlycA (r = 0.45, p = 0.00049) in asymptomatics, revealing an 'inflammaging" signature which was absent in HAM/TSP. GlycA levels were higher in women (p = 0.0069), but cytokine levels did not differ between the sexes. IFN-γ (p = 0.007) and IL-17A (p = 0.0001) levels were increased in untreated HAM/TSP Multivariable logistic regression identified IL-17A and proviral load as independent determinants of clinical status, resulting in modest accuracy of predicting HAM/TSP status (64.1%), while a machine learning-derived decision tree classified HAM/TSP patients with 90.7% accuracy. Pre-treatment GlycA and TNF levels significantly predicted clinical worsening (measured by Osame Motor Disability Scale), independent of proviral load. In addition, a poor prednisolone response was significantly correlated with higher post-treatment IFN-γ levels. Likewise, a transcriptomic IFN signaling score, significantly correlated with previously proposed HAM/TSP biomarkers (CASP5/CXCL10/FCGR1A/STAT1), was efficiently blunted by in vitro prednisolone treatment of PBMC from PLHTLV-1 and incident HAM/TSP.

CONCLUSIONS

An age-related increase in systemic IL-6/GlycA levels reveals inflammaging in PLHTLV-1, in the absence of neurological disease. IFN-γ and IL-17A are biomarkers of untreated HAM/TSP, while pre-treatment GlycA and TNF predict therapeutic response to prednisolone pulse therapy, paving the way for a precision medicine approach in HAM/TSP.

Inflammation, Immune Senescence, and Dysregulated Immune Regulation in the Elderly

An optimal immune response requires the appropriate interaction between the innate and the adaptive arms of the immune system as well as a proper balance of activation and regulation. After decades of life, the aging immune system is continuously exposed to immune stressors and inflammatory assaults that lead to immune senescence. In this review, we will discuss inflammaging in the elderly, specifically concentrating on IL-6 and IL-1b in the context of T lymphocytes, and how inflammation is related to mortality and morbidities, specifically cardiovascular disease and cancer. Although a number of studies suggests that the anti-inflammatory cytokine TGF-b is elevated in the elderly, heightened inflammation persists. Thus, the regulation of the immune response and the ability to return the immune system to homeostasis is also important. Therefore, we will discuss cellular alterations in aging, concentrating on senescent T cells and CD4+ CD25+ FOXP3+ regulatory T cells (Tregs) in aging

Immunological age prediction in HIV-infected, ART-treated individuals

Anti-retroviral therapy (ART) improves life expectancy in people living with HIV (PWH), but it remains unclear how chronic HIV infection affects normal aging of the immune system. Plasma cell-free protein expression and immune phenotypes were assessed in blood from ART treated PWH (19-77yrs, n = 106) and age-matched, HIV-negative controls (HC, n = 103). Using univariate spearman correlation, we identified 277 and 491 age-associated parameters out of a total 1,357 in HC and PWH, respectively. PWH exhibited shared and distinct age-associated immune profiles compared to HC highlighting the effect of HIV infection on immunological aging. Our analysis resulted in an 8-parameter, plasma-detectable inflammatory index that correlated with chronological age of all study participants but was higher overall in PWH. Additionally, predictive modeling for age in HC participants and age-associated parameters generated a 25-parameter signature, IMAP-25, with 70% and 53% accuracy in HC and PWH, respectively. Applying the IMAP-25 signature to immunological data from PWH revealed accelerated aging in PWH by 5.6 yrs. Overall, our results demonstrate that immune signatures, easily monitored in human blood samples, can be used as an indicator of one’s ‘immunological age’ during ART-treated HIV infection and can be applied to other disease states that affect the immune system.