We investigated the interactions between human immunodeficiency virus (HIV) infection and aging and their effects on brain function demands by means of functional magnetic resonance imaging (fMRI). A ...multiple-regression model was used to study the association and interaction between fMRI measures, HIV serostatus, and age for 26 HIV-infected subjects and 25 seronegative subjects. Although HIV serostatus and age independently affected fMRI measures, no interaction occurred. Functional brain demands in HIV-positive subjects were equivalent to those of HIV-negative subjects who were 15-20 years older. Frailty parallels between HIV infection and aging could result from continued immunological challenges depleting resources and triggering increased metabolic demands. In the future, fMRI could be a noninvasive biomarker to assess HIV infection in the brain.
The accumulation of soluble proteins and metabolites during wakefulness and their clearance during sleep via the glymphatic system occurs in healthy adults and is disturbed in some neurological ...conditions. Such diurnal variations in the cerebrospinal fluid (CSF) proteins produced outside the central nervous system and entering via the blood-brain barrier (BBB) have not been evaluated in people with HIV (PWH). CSF and blood were collected in 165 PWH at six US centers between 2003 and 2007. The time of collection was compared to CSF albumin, globulin, and total protein concentrations using bivariate and multivariate regression. Participants all took antiretroviral therapy (ART) and were mostly middle-aged (median age 44.0 years) men (78.8%), with AIDS (77.0%), plasma HIV RNA ≤ 200 copies/mL (75.8%), and immune recovery (median CD4+ T-cell count 414/µL). CSF was collected at median 1:10 p.m. (range 9:00 a.m. to 5:20 p.m.) and within a median of 15 min of blood collection. A later time of CSF collection was associated with higher total protein (
= 0.0077) and albumin (
= 0.057) in CSF but not in serum, and was additionally associated with higher CSF globulin (
= 0.013). The glymphatic clearance of albumin, globulin, and total protein is preserved in PWH. The analyses of soluble biomarkers in CSF should account for the time of collection.
The Human Immunodeficiency Virus (HIV) infects cells in the Central Nervous System (CNS), where the access of antiretrovirals and antibodies that can kill the virus may be challenging. As a result of ...the early HIV entry in the brain, infected individuals develop inflammation and neurological deficits at various levels, which are aggravated by drugs of abuse. In the non-human primate model of HIV, we have previously shown that drugs of abuse such as Methamphetamine (Meth) increase brain viral load in correlation with a higher number of CCR5-expressing myeloid cells. CCR5 is a chemokine receptor that may be involved in increasing inflammation, but also, it is a co-receptor for viral entry into target cells. CCR5-expressing myeloid cells are the main targets of HIV in the CNS. Thus, the identification of factors and mechanisms that impact the expression of CCR5 in the brain is critical, as changes in CCR5 levels may affect the infection in the brain. Using a well-characterized in vitro system, with the THP1 human macrophage cell line, we have investigated the hypothesis that the expression of CCR5 is acutely affected by Meth, and examined pathways by which this effect could happen. We found that Meth plays a direct role by regulating the abundance and nuclear translocation of transcription factors with binding sites in the CCR5 promoter. However, we found that the main factor that modifies the CCR5 gene promoter at the epigenetic level towards transcription is Dopamine (DA), a neurotransmitter that is produced primarily in brain regions that are rich in dopaminergic neurons. In THP1 cells, the effect of DA on innate immune CCR5 transcription was mediated by DA receptors (DRDs), mainly DRD4. We also identified a role for DRD1 in suppressing CCR5 expression in this myeloid cell system, with potential implications for therapy. The effect of DA on innate immune CCR5 expression was also detectable on the cell surface during acute time-points, using low doses. In addition, HIV Tat acted by enhancing the surface expression of CCR5, in spite of its poor effect on transcription. Overall, our data suggests that the exposure of myeloid cells to Meth in the context of presence of HIV peptides such as Tat, may affect the number of HIV targets by modulating CCR5 expression, through a combination of DA-dependent and-independent mechanisms. Other drugs that increase DA may affect similar mechanisms. The implications of these epigenetic and translational mechanisms in enhancing HIV infection in the brain and elsewhere are demonstrated.
Even when antiretroviral therapy (ART) is started early after infection, HIV DNA might persist in the central nervous system (CNS), possibly contributing to inflammation, brain damage and ...neurocognitive impairment. Paired blood and cerebrospinal fluid (CSF) were collected from 16 HIV-infected individuals on suppressive ART: 9 participants started ART <4 months of the estimated date of infection (EDI) ("early ART"), and 7 participants started ART >14 months after EDI ("late ART"). For each participant, neurocognitive functioning was measured by Global Deficit Score (GDS). HIV DNA levels were measured in peripheral blood mononuclear cells (PBMCs) and CSF cell pellets by droplet digital (dd)PCR. Soluble markers of inflammation (sCD163, IL-6, MCP-1, TNF-α) and neuronal damage (neurofilament light NFL) were measured in blood and CSF supernatant by immunoassays. HIV-1 partial C2V3 env deep sequencing data (Roche 454) were obtained for 8 paired PBMC and CSF specimens and used for phylogenetic and compartmentalization analysis. Median exposure to ART at the time of sampling was 2.6 years (IQR: 2.2-3.7) and did not differ between groups. We observed that early ART was significantly associated with lower molecular diversity of HIV DNA in CSF (p<0.05), and lower IL-6 levels in CSF (p = 0.02), but no difference for GDS, NFL, or HIV DNA detectability compared to late ART. Compartmentalization of HIV DNA populations between CSF and blood was detected in 6 out of 8 participants with available paired HIV DNA sequences (2 from early and 4 from late ART group). Phylogenetic analysis confirmed the presence of monophyletic HIV DNA populations within the CSF in 7 participants, and the same population was repeatedly sampled over a 5 months period in one participant with longitudinal sampling. Such compartmentalized provirus in the CNS needs to be considered for the design of future eradication strategies and might contribute to the neuropathogenesis of HIV.
Monocytes and macrophages activation are crucial in human immunodeficiency virus (HIV) central nervous system (CNS) infection and HIV associated neurocognitive disorders (HAND) pathogenesis. The ...soluble form of CD14 (sCD14) is a marker of monocyte activation. We hypothesized that sCD14 levels would be lower in people with HIV-1 subtype C (HIV-1C) than in HIV-1B owing to a variant Tat cysteine dimotif (C30S31) with reduced chemotactic activity. A total of 68 paired cerebrospinal fluid (CSF) and blood samples from people with HIV (PWH); 27 samples of the HIV-1B subtype and 40 of the non-B HIV-1 subtypes (including 26,HIV-1C), and 18 HIV-negative controls were included. sCD14 levels were quantified using a high-sensitivity enzyme-linked immunosorbent assay. sCD14 increase in serum, but not in CSF, was higher in samples from HIV-1B than HIV-1C (p = 0.002; Cohen's d, 0.7). CSF or serum sCD14 values were not correlated with global deficit score or specific cognitive domains. The impact of HIV-1 on monocyte stimulation biomarkers evaluated by sCD14 in serum was subtype-dependent, higher in HIV-1B than HIV-1C, consistent with reduced chemotactic activity as hypothesized.
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•sCD14 increase in serum, but not in CSF, was higher in samples from HIV-1B than HIV-1C.•This was owing to a variant Tat cysteine dimotif (C30S) with reduced chemotactic activity in HI-1C.•CSF or serum sCD14 values were not correlated with global deficit score or specific cognitive domains.
Background & Aims The ability to obtain unlimited numbers of human hepatocytes would improve the development of cell-based therapies for liver diseases, facilitate the study of liver biology, and ...improve the early stages of drug discovery. Embryonic stem cells are pluripotent, potentially can differentiate into any cell type, and therefore could be developed as a source of human hepatocytes. Methods To generate human hepatocytes, human embryonic stem cells were differentiated by sequential culture in fibroblast growth factor 2 and human activin-A, hepatocyte growth factor, and dexamethasone. Functional hepatocytes were isolated by sorting for surface asialoglycoprotein-receptor expression. Characterization was performed by real-time polymerase chain reaction, immunohistochemistry, immunoblot, functional assays, and transplantation. Results Embryonic stem cell–derived hepatocytes expressed liver-specific genes, but not genes representing other lineages, secreted functional human liver–specific proteins similar to those of primary human hepatocytes, and showed human hepatocyte cytochrome P450 metabolic activity. Serum from rodents given injections of embryonic stem cell–derived hepatocytes contained significant amounts of human albumin and α1-antitrypsin. Colonies of cytokeratin-18 and human albumin–expressing cells were present in the livers of recipient animals. Conclusions Human embryonic stem cells can be differentiated into cells with many characteristics of primary human hepatocytes. Hepatocyte-like cells can be enriched and recovered based on asialoglycoprotein-receptor expression and potentially could be used in drug discovery research and developed as therapeutics.
Here we evaluated whether neurocognitive disorders in HIV-infected individuals on effective antiretroviral therapy (ART) are associated with persistent monocyte activation as indexed by levels of ...soluble CD163 (sCD163), shed by monocyte/macrophages.
Chronically, HIV-infected individuals were examined at two consecutive visits median interquartile range (IQR) 16 (7-32) months apart. All patients were on ART and durably virologically suppressed (plasma HIV RNA <50 copies/ml) at all visits. Thirty-four age-matched HIV-seronegative patients were used as controls.
A global deficit score (GDS) was calculated based on comprehensive neuropsychological assessment according to standard methods. Neuropsychological and medical data were used to assign neurocognitive status according to published guidelines for HIV-associated neurocognitive disorders (HAND) as follows: neuropsychologically normal (NP-nml), asymptomatic neuropsychological impairment (ANI) and minor neurocognitive disorder (MND). sCD163 in plasma and cerebrospinal fluid was measured using ELISA.
GDS-impaired patients had higher plasma sCD163 than those who were not impaired median (IQR) 1401 ng/ml (1057-2258) versus 955 ng/ml (586-1313); Wilcoxon P=0.028. Patients with MND (N=6) had significantly higher plasma sCD163 than ANI (P=0.04) or NP-nml (P=0.02). Whereas plasma sCD163 levels dropped in patients who were stably GDS-unimpaired after the first visit (P<0.032), levels remained elevated in those who remained GDS-impaired (P=0.50).
These findings are consistent with persistent monocyte/macrophage activation in neurophysiologically impaired HIV-infected individuals despite virally suppressive ART. Overall, these observations underscore the significance of monocyte/macrophage immune responses in HIV, persistent monocyte activation in HAND and the value of sCD163, as a plasma marker of neurocognitive impairment.
Abstract HIV-associated neurocognitive disorders (HAND) still occur in approximately 50% of HIV patients, and therapies to combat HAND progression are urgently needed. HIV proteins are released from ...infected cells and cause neuronal damage, possibly through mitochondrial abnormalities. Altered mitochondrial fission and fusion is implicated in several neurodegenerative disorders. Here, we hypothesized that mitochondrial fission/fusion may be dysregulated in neurons during HAND. We have identified decreased mitochondrial fission protein (dynamin 1-like; DNM1L) in frontal cortex tissues of HAND donors, along with enlarged and elongated mitochondria localized to the soma of damaged neurons. Similar pathology was observed in the brains of GFAP-gp120 tg mice. In vitro, recombinant gp120 decreased total and active DNM1L levels, reduced the level of Mitotracker staining, and increased extracellular acidification rate (ECAR) in primary neurons. DNM1L knockdown enhanced the effects of gp120 as measured by reduced Mitotracker signal in the treated cells. Interestingly, overexpression of DNM1L increased the level of Mitotracker staining in primary rat neurons and reduced neuroinflammation and neurodegeneration in the GFAP-gp120-tg mice. These data suggest that mitochondrial biogenesis dynamics are shifted towards mitochondrial fusion in brains of HAND patients and this may be due to gp120-induced reduction in DNM1L activity. Promoting mitochondrial fission during HIV infection of the CNS may restore mitochondrial biogenesis and prevent neurodegeneration.
Abstract
Background
Human immunodeficiency virus (HIV) infection leads to blood–brain barrier (BBB) dysfunction that does not resolve despite viral suppression on antiretroviral therapy (ART) and is ...associated with adverse clinical outcomes. In preclinical models, cannabis restores BBB integrity.
Methods
We studied persons with HIV (PWH) and HIV-negative (HIV−) individuals who had used cannabis recently. We assessed 2 biomarkers of BBB permeability: the cerebrospinal fluid (CSF) to serum albumin ratio (CSAR) and CSF levels of soluble urokinase plasminogen activator receptor (suPAR), a receptor for uPA, a matrix-degrading proteolytic enzyme that disrupts the BBB. A composite index of the BBB markers was created using principal components analysis. Neural injury was assessed using neurofilament light (NFL) in CSF by immunoassay.
Results
Participants were 45 PWH and 30 HIV− individuals of similar age and ethnicity. Among PWH, higher CSF suPAR levels correlated with higher CSAR values (r = 0.47, P < .001). PWH had higher (more abnormal) BBB index values than HIV− individuals (mean ± SD, 0.361 ± 1.20 vs −0.501 ± 1.11; P = .0214). HIV serostatus interacted with cannabis use frequency, such that more frequent use of cannabis was associated with lower BBB index values in PWH but not in HIV− individuals. Worse BBB index values were associated with higher NFL in CSF (r = 0.380, P = .0169).
Conclusions
Cannabis may have a beneficial impact on HIV-associated BBB injury. Since BBB disruption may permit increased entry of toxins such as microbial antigens and inflammatory mediators, with consequent CNS injury, these results support a potential therapeutic role of cannabis among PWH and may have important treatment implications for ART effectiveness and toxicity.
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