Showing papers in "Journal of Neuroimmune Pharmacology in 2021"

Is COVID-19 Gender-sensitive?

Abstract: While clinical characteristics exhibit that susceptibility to COVID-19 infection is equally likely between males and females, clinical outcomes show that males experience both a higher severity and fatality for COVID-19 infection than females. This review examines the evidence for these sex and gender differences and aims to illustrate possible mechanisms behind such sensitivity. Successful entry of SARS-CoV-2 into the body is dependent on the angiotensin-converting enzyme 2 (ACE2) receptor and the transmembrane protease serine 2 (TMPRSS2). Thus, sex-based differences in the expression of the ACE2 receptor and TMPRSS2 may explain the disparities in COVID-19 severity and fatality. Furthermore, these disparities may also be attributed to sex-based difference in immunological responses. Finally, the differences in clinical outcomes of COVID-19 infections between men and women may be due to gendered differences in behaviors, such as smoking, and prevalence to comorbidities. An understanding of the sex and gender sensitivities of COVID-19 infection is a necessary component towards the creation of effective treatment options and therapies for the virus. Graphical abstract.

Cerebral Vascular Toxicity of Antiretroviral Therapy.

Abstract: HIV infection is associated with comorbidities that are likely to be driven not only by HIV itself, but also by the toxicity of long-term use of antiretroviral therapy (ART). Indeed, increasing evidence demonstrates that the antiretroviral drugs used for HIV treatment have toxic effects resulting in various cellular and tissue pathologies. The blood-brain barrier (BBB) is a modulated anatomophysiological interface which separates and controls substance exchange between the blood and the brain parenchyma; therefore, it is particularly exposed to ART-induced toxicity. Balancing the health risks and gains of ART has to be considered in order to maximize the positive effects of therapy. The current review discusses the cerebrovascular toxicity of ART, with the focus on mitochondrial dysfunction. Graphical Abstract Graphical representation of the interactions between HIV, antiretroviral therapy (ART), and the blood-brain barrier (BBB).

SARS-CoV-2 Spike Protein Disrupts Blood-Brain Barrier Integrity via RhoA Activation.

Abstract: The SARS-CoV-2 spike protein has been shown to disrupt blood-brain barrier (BBB) function, but its pathogenic mechanism of action is unknown. Whether angiotensin converting enzyme 2 (ACE2), the viral binding site for SARS-CoV-2, contributes to the spike protein-induced barrier disruption also remains unclear. Here, a 3D-BBB microfluidic model was used to interrogate mechanisms by which the spike protein may facilitate barrier dysfunction. The spike protein upregulated the expression of ACE2 in response to laminar shear stress. Moreover, interrogating the role of ACE2 showed that knock-down affected endothelial barrier properties. These results identify a possible role of ACE2 in barrier homeostasis. Analysis of RhoA, a key molecule in regulating endothelial cytoskeleton and tight junction complex dynamics, reveals that the spike protein triggers RhoA activation. Inhibition of RhoA with C3 transferase rescues its effect on tight junction disassembly. Overall, these results indicate a possible means by which the engagement of SARS-CoV-2 with ACE2 facilitates disruption of the BBB via RhoA activation. Understanding how SARS-CoV-2 dysregulates the BBB may lead to strategies to prevent the neurological deficits seen in COVID-19 patients.

Beneficial and Adverse Effects of cART Affect Neurocognitive Function in HIV-1 Infection: Balancing Viral Suppression against Neuronal Stress and Injury

Abstract: HIV-associated neurocognitive disorders (HAND) persist despite the successful introduction of combination antiretroviral therapy (cART). While insufficient concentration of certain antiretrovirals (ARV) may lead to incomplete viral suppression in the brain, many ARVs are found to cause neuropsychiatric adverse effects, indicating their penetration into the central nervous system (CNS). Several lines of evidence suggest shared critical roles of oxidative and endoplasmic reticulum stress, compromised neuronal energy homeostasis, and autophagy in the promotion of neuronal dysfunction associated with both HIV-1 infection and long-term cART or ARV use. As the lifespans of HIV patients are increased, unique challenges have surfaced. Longer lives convey prolonged exposure of the CNS to viral toxins, neurotoxic ARVs, polypharmacy with prescribed or illicit drug use, and age-related diseases. All of these factors can contribute to increased risks for the development of neuropsychiatric conditions and cognitive impairment, which can significantly impact patient well-being, cART adherence, and overall health outcome. Strategies to increase the penetration of cART into the brain to lower viral toxicity may detrimentally increase ARV neurotoxicity and neuropsychiatric adverse effects. As clinicians attempt to control peripheral viremia in an aging population of HIV-infected patients, they must navigate an increasingly complex myriad of comorbidities, pharmacogenetics, drug-drug interactions, and psychiatric and cognitive dysfunction. Here we review in comparison to the neuropathological effects of HIV-1 the available information on neuropsychiatric adverse effects and neurotoxicity of clinically used ARV and cART. It appears altogether that future cART aiming at controlling HIV-1 in the CNS and preventing HAND will require an intricate balancing act of suppressing viral replication while minimizing neurotoxicity, impairment of neurocognition, and neuropsychiatric adverse effects. Graphical abstract Schematic summary of the effects exerted on the brain and neurocognitive function by HIV-1 infection, comorbidities, psychostimulatory, illicit drugs, therapeutic drugs, such as antiretrovirals, the resulting polypharmacy and aging, as well as the potential interactions of all these factors.

CNS Neurotoxicity of Antiretrovirals.

Abstract: The development of novel antiretroviral treatments has led to a significant turning point in the fight against HIV. Although therapy leads to virologic suppression and prolonged life expectancies, HIV-associated neurocognitive disorder (HAND) remains prevalent. While various hypotheses have been proposed to explain this phenomenon, a growing body of literature explores the neurotoxic effects of antiretroviral therapy. Research to date brings into question the potential role of such medications in neurocognitive and neuropsychiatric impairment seen in HIV-positive patients. This review highlights recent findings and controversies in cellular, molecular, and clinical neurotoxicity of antiretrovirals. It explores the pathogenesis of such toxicity and relates it to clinical manifestations in each medication class. The concept of accelerated aging in persons living with HIV (PLWH) as well as potential treatments for HAND are also discussed. Ultimately, this article hopes to educate clinicians and basic scientists about the neurotoxic effects of antiretrovirals and spur future scientific investigation into this important topic. Graphical Abstract.

Can Cytokine Blocking Prevent Depression in COVID-19 Survivors?

Abstract: Current insight on inflammation in psychiatry suggests that infection-triggered perturbation of immune homeostasis could foster psychopathology (Miller and Raison 2016). High rates of psychiatric disorders have been reported during and after coronavirus infection (Rogers et al. 2020).We also observed a psychopathological impact of COVID-19, with emergent depression and post-traumatic stress disorder (PTSD) after COVID-19 associated to systemic inflammation index (SII) during the acute illness (Mazza et al. 2020): 31% of patients self-rated in the psychopathological range for depression and 28% for PTSD, one month after hospital discharge, complete viral clearance and clinical recovery. Studies revealed persistent low-grade inflammation in mood disorders, and pointed at interleukin (IL)-1β and IL-6 as inflammatory cytokines implicated in major depression and its detrimental outcomes(Arteaga-Henríquez et al. 2019). Severe COVID-19 induces a ‘cytokine storm’ involving massive release of IL-1β and IL-6. Pharmacological blockade of both cytokines was explored and we reported benefits on hyper-inflammation and progression to respiratory failure with high-dose anakinra (Cavalli et al. 2020), a recombinant version of the human IL-1β receptor antagonist, and less clear effects with tocilizumab (Campochiaro et al. 2020), a monoclonal antibody targeting the IL-6 receptor. Given the central role of IL-1 and IL-6 in depression, we hypothesize that depressive symptoms should be lower in COVID-19 survivors treated with cytokine-blocking agents. We now prospectively evaluated the severity of depressive symptoms (Zung Self-rating Depression Scale, ZSDS) and PTSD (revised Impact of Event Scale, IES-R), one and three months after discharge, in 84 male COVID-19 survivors who during hospitalization had received the best available medical treatment at the time, including hydroxychloroquine, lopinavir/ritonavir, and respiratory support, alone or combined with anakinra (5 mg/Kg/day twice daily until clinical benefit, defined as sustained improvement of respiratory parameters and 75% reduction of serum C-reactive protein, CRP), or tocilizumab (single i.v. dose of 400 mg, followed by a second dose 24-hour apart in the event of further worsening in respiratory function). We also extracted from available charts levels of inflammatory markers during acute COVID-19, at hospital admission and before discharge: CRP, neutrophil/lymphocyte ratio (NLR), and SII. The protocol was approved by the local ethical committee. At discharge, all patients fulfilled grade 1 of the 7-point WHO Clinical severity scale (Discharge from hospital with resumption of normal activities). We tested the effect of treatment (standard management vs. standard management plus cytokine-blocking agents) and of inflammatory markers on the psychopathological status (selfreport scores) by modelling the influences of the predictors on the outcomes in the context of the General Linear Model (GLM) or Generalized Linear Model (GZLM) as appropriate, and calculating the statistical significance of the effect of the single independent factors on the dependent variables by least squares parametric estimates of predictor variables in the GLM, or by the likelihood ratio iterative estimation procedure, providing the most asymptotically efficient test in the GLZM. Analyses of multivariate and univariate effects were performed with a commercially available software (StatSoft Statistica 12, Tulsa, OK, USA) and following standard computational procedures. * Francesco Benedetti benedetti.francesco@hsr.it

ACE-2-interacting Domain of SARS-CoV-2 (AIDS) Peptide Suppresses Inflammation to Reduce Fever and Protect Lungs and Heart in Mice: Implications for COVID-19 Therapy.

Abstract: COVID-19 is an infectious respiratory illness caused by the virus strain severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and until now, there is no effective therapy against COVID-19. Since SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) for entering into host cells, to target COVID-19 from therapeutic angle, we engineered a hexapeptide corresponding to the ACE2-interacting domain of SARS-CoV-2 (AIDS) that inhibits the association between receptor-binding domain-containing spike S1 and ACE-2. Accordingly, wild type (wt), but not mutated (m), AIDS peptide inhibited SARS-CoV-2 spike S1-induced activation of NF-κB and expression of IL-6 in human lungs cells. Interestingly, intranasal intoxication of C57/BL6 mice with recombinant SARS-CoV-2 spike S1 led to fever, increase in IL-6 in lungs, infiltration of neutrophils into the lungs, arrhythmias, and impairment in locomotor activities, mimicking some of the important symptoms of COVID-19. However, intranasal treatment with wtAIDS, but not mAIDS, peptide reduced fever, protected lungs, improved heart function, and enhanced locomotor activities in SARS-CoV-2 spike S1-intoxicated mice. Therefore, selective targeting of ACE2-to-SARS-CoV-2 interaction by wtAIDS may be beneficial for COVID-19.

Mitochondrial Dynamics in SARS-COV2 Spike Protein Treated Human Microglia: Implications for Neuro-COVID.

Abstract: Emerging clinical data from the current COVID-19 pandemic suggests that ~ 40% of COVID-19 patients develop neurological symptoms attributed to viral encephalitis while in COVID long haulers chronic neuro-inflammation and neuronal damage result in a syndrome described as Neuro-COVID. We hypothesize that SAR-COV2 induces mitochondrial dysfunction and activation of the mitochondrial-dependent intrinsic apoptotic pathway, resulting in microglial and neuronal apoptosis. The goal of our study was to determine the effect of SARS-COV2 on mitochondrial biogenesis and to monitor cell apoptosis in human microglia non-invasively in real time using Raman spectroscopy, providing a unique spatio-temporal information on mitochondrial function in live cells. We treated human microglia with SARS-COV2 spike protein and examined the levels of cytokines and reactive oxygen species (ROS) production, determined the effect of SARS-COV2 on mitochondrial biogenesis and examined the changes in molecular composition of phospholipids. Our results show that SARS- COV2 spike protein increases the levels of pro-inflammatory cytokines and ROS production, increases apoptosis and increases the oxygen consumption rate (OCR) in microglial cells. Increases in OCR are indicative of increased ROS production and oxidative stress suggesting that SARS-COV2 induced cell death. Raman spectroscopy yielded significant differences in phospholipids such as Phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanolamine (PE) and phosphatidylcholine (PC), which account for ~ 80% of mitochondrial membrane lipids between SARS-COV2 treated and untreated microglial cells. These data provide important mechanistic insights into SARS-COV2 induced mitochondrial dysfunction which underlies neuropathology associated with Neuro-COVID.

Lysosomal Stress Response (LSR): Physiological Importance and Pathological Relevance.

Abstract: Extensive work has characterized endoplasmic reticulum (ER) and mitochondrial stress responses. In contrast, very little has been published about stress responses in lysosomes; subcellular acidic organelles that are physiologically important and are of pathological relevance. The greater lysosomal system is dynamic and is comprised of endosomes, lysosomes, multivesicular bodies, autophagosomes, and autophagolysosomes. They are important regulators of cellular physiology, they represent about 5% of the total cellular volume, they are heterogeneous in their sizes and distribution patterns, they are electron dense, and their subcellular positioning within cells varies in response to stimuli, insults and pH. These organelles are also integral to the pathogenesis of lysosomal storage diseases and it is increasingly recognized that lysosomes play important roles in the pathogenesis of such diverse conditions as neurodegenerative disorders and cancer. The purpose of this review is to focus attention on lysosomal stress responses (LSR), compare LSR with better characterized stress responses in ER and mitochondria, and form a framework for future characterizations of LSR. We synthesized data into the concept of LSR and present it here such that the definition of LSR can be modified as new knowledge is added and specific therapeutics are developed.

Eugenol, a Component of Holy Basil (Tulsi) and Common Spice Clove, Inhibits the Interaction Between SARS-CoV-2 Spike S1 and ACE2 to Induce Therapeutic Responses

Abstract: Spike S1 of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) binds to angiotensin-converting enzyme 2 (ACE2) on host cells to enter the cell and initiate COVID-19. Since ACE2 is a favorable enzyme, we were interested in finding a molecule capable of binding spike S1, but not ACE2, and inhibiting the interaction between spike S1 and ACE2. Holy basil (Tulsi) has a long history as a medicine for different human disorders. Therefore, we screened different components of Tulsi leaf and found that eugenol, but not other major components (e.g. ursolic acid, oleanolic acid and β-caryophylline), inhibited the interaction between spike S1 and ACE2 in an AlphaScreen-based assay. By in silico analysis and thermal shift assay, we also observed that eugenol associated with spike S1, but not ACE2. Accordingly, eugenol strongly suppressed the entry of pseudotyped SARS-CoV-2, but not vesicular stomatitis virus (VSV), into human ACE2-expressing HEK293 cells. Eugenol also reduced SARS-CoV-2 spike S1-induced activation of NF-κB and the expression of IL-6, IL-1β and TNFα in human A549 lung cells. Moreover, oral treatment with eugenol reduced lung inflammation, decreased fever, improved heart function, and enhanced locomotor activities in SARS-CoV-2 spike S1-intoxicated mice. Therefore, selective targeting of SARS-CoV-2 spike S1, but not ACE2, by eugenol may be beneficial for COVID-19 treatment.

A Role for Extracellular Vesicles in SARS-CoV-2 Therapeutics and Prevention.

Abstract: Extracellular vesicles (EVs) are the common designation for ectosomes, microparticles and microvesicles serving dominant roles in intercellular communication. Both viable and dying cells release EVs to the extracellular environment for transfer of cell, immune and infectious materials. Defined morphologically as lipid bi-layered structures EVs show molecular, biochemical, distribution, and entry mechanisms similar to viruses within cells and tissues. In recent years their functional capacities have been harnessed to deliver biomolecules and drugs and immunological agents to specific cells and organs of interest or disease. Interest in EVs as putative vaccines or drug delivery vehicles are substantial. The vesicles have properties of receptors nanoassembly on their surface. EVs can interact with specific immunocytes that include antigen presenting cells (dendritic cells and other mononuclear phagocytes) to elicit immune responses or affect tissue and cellular homeostasis or disease. Due to potential advantages like biocompatibility, biodegradation and efficient immune activation, EVs have gained attraction for the development of treatment or a vaccine system against the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) infection. In this review efforts to use EVs to contain SARS CoV-2 and affect the current viral pandemic are discussed. An emphasis is made on mesenchymal stem cell derived EVs’ as a vaccine candidate delivery system.

Immunomodulatory Potential of Cannabidiol in Multiple Sclerosis: a Systematic Review.

Abstract: Multiple sclerosis (MS) is the most common chronic autoimmune disease of the central nervous system. Efficacy of treatments for MS is associated with risk of adverse effects, and effective and well-tolerated drugs remain a major unmet need. Cannabis (Cannabis sativa L., fam. Cannabaceae) and cannabinoids are popular among MS patients to treat spasticity and pain. Cannabinoids are endowed with remarkable immunomodulating properties, and in particular the non-psychotropic cannabinoid cannabidiol (CBD) is increasingly recognized as anti-inflammatory and immunosuppressive, nevertheless with excellent tolerability even at high doses. In this systematic review, we retrieved and critically evaluated available evidence regarding the immune and disease-modifying effects of CBD in experimental autoimmune encephalomyelitis (EAE) and in MS. Evidence in rodent models of EAE strongly supports CBD as effective, while clinical evidence is still limited and usually negative, due to paucity of studies and possibly to the use of suboptimal dosing regimens. Better characterization of targets acted upon by CBD in MS should be obtained in ex vivo/in vitro studies in human immune cells, and higher doses should be tested in well-designed clinical trials with clinically relevant efficacy endpoints. Graphical Abstract.

Pretreatment of Indobufen and Aspirin and their Combinations with Clopidogrel or Ticagrelor Alleviates Inflammasome Mediated Pyroptosis Via Inhibiting NF-κB/NLRP3 Pathway in Ischemic Stroke

Abstract: Increasing studies showed that several anti-platelet drugs turned out to be a promising strategy for inflammatory response. In this study, we investigated the protective efficiency of pretreatment of indobufen or aspirin combined with clopidogrel or ticagrelor (IACT) on cerebral ischemic injury via NF-κB/NLRP3 pathway. Ischemia/reperfusion (I/R) injury was simulated in vivo by middle cerebral artery occlusion/reperfusion (MCAO/R) model, and rats were pretreated with indobufen and aspirin and their combinations with clopidogrel or ticagrelor respectively. The platelet aggregation, cerebral infarct size, water content, neurological impairment and LDH release were measured. The relative expression of inflammasome mediated pyroptosis was determined by ELISA, RT-PCR, Tunel, Immunofluorescence and Western blotting as appropriate. In vitro, I/R injury was simulated in PC12 cells using oxygen glucose deprivation/reperfusion (OGD/R) and Lipopolysaccharide (LPS) to induce pyroptosis. The effect of combinations were significantly greater than MCAO/R group on decreasing the platelet aggregation, infarct size, brain edema, LDH release and neurologic impairment. LPS aggravated I/R-induced PC12 cell injury, which was significantly suppressed by pretreatment of IACT and Bay11-7082. Mechanistically, IACT alleviated transcriptionally encoded IL-1β, IL-18 and NLRP3 via inhibiting nuclear transportation of NF-κB. Importantly, at protein level, NLRP3, Caspase-1, IL-18, IL-1β and GSDMD were significantly decreased in combination groups both in vivo and vitro. IACT reduce inflammasome mediated pyroptosis in MCAO/R rats and OGD/R PC12 cells through inhibiting NF-κB/NLRP3 signaling pathway, which suggests that drug combination is a protective strategy with clinical potential against I/R-induced injury. Graphical abstract.

Evaluating Neurodevelopmental Consequences of Perinatal Exposure to Antiretroviral Drugs: Current Challenges and New Approaches.

Abstract: As antiretroviral therapy (ART) becomes increasingly affordable and accessible to women of childbearing age across the globe, the number of children who are exposed to Human Immunodeficiency Viruses (HIV) but remain uninfected is on the rise, almost all of whom were also exposed to ART perinatally. Although ART has successfully aided in the decline of mother-to-child-transmission of HIV, the long-term effects of in utero exposure to ART on fetal and postnatal neurodevelopment remain unclear. Evaluating the safety and efficacy of therapeutic drugs for pregnant women is a challenge due to the historic limitations on their inclusion in clinical trials and the dynamic physiological states during pregnancy that can alter the pharmacokinetics of drug metabolism and fetal drug exposure. Thus, much of our data on the potential consequences of ART drugs on the developing nervous system comes from preclinical animal models and clinical observational studies. In this review, we will discuss the current state of knowledge and existing approaches to investigate whether ART affects fetal brain development, and describe novel human stem cell-based strategies that may provide additional information to better predict the impact of specific drugs on the human central nervous system.

Hydrogen Sulfide Reverses LPS-Induced Behavioral Deficits by Suppressing Microglial Activation and Promoting M2 Polarization

Abstract: Activation of microglia is a hallmark of neuroinflammation and has been implicated in the development of many psychiatric disorders. Hydrogen sulfide (H2S); a gasotransmitter has recently emerged as a potent antioxidant and anti-inflammatory molecule. However, the protective potential of H2S and its underpin molecular mechanisms in neuroinflammation associated behavioral deficits are still unknown. The present study has been designed to investigate the effect of sodium hydrogen sulfide (NaHS; a source of H2S) on microglial activation and associated behavior phenotype in response to lipopolysaccharide (LPS)-induced neuroinflammation. LPS treatment decreased H2S levels with a concomitant increase in reactive oxygen species (ROS) in the cortex and hippocampus. However, NaHS administration restored the endogenous H2S levels to the normal and decreased ROS levels. NaHS supplementation reduced the number of active microglia in the cortex and hippocampus of LPS treated animals. Morphological analysis of microglia showed significant increase in microglial density, span ratio and soma area in the cortex and hippocampus of LPS treated animals which was decreased by NaHS supplementation. Moreover, NaHS administration reduced the expression of microglial M1 phenotype markers (IL-1β, TNF-α and nitrite) and concomitantly increased the expression of M2 phenotype markers (IL-4 and TGF-β) in the brain regions of LPS treated animals. Furthermore, LPS-induced anxiety-like behavior assessed by open field test and elevated plus maze was reversed by NaHS supplementation. Taken together, these findings suggest that H2S supplementation ameliorates LPS-induced behavioral deficits by suppressing pro-inflammatory and promoting anti-inflammatory microglial response. Therefore, H2S releasing drugs may be potential therapeutics to treat neuroinflammation associated psychiatric disorders.

CBD Suppression of EAE Is Correlated with Early Inhibition of Splenic IFN-γ + CD8+ T Cells and Modest Inhibition of Neuroinflammation

Abstract: In this study cannabidiol (CBD) was administered orally to determine its effects and mechanisms in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS). We hypothesized that 75 mg/kg of oral CBD given for 5 days after initiation of disease would reduce EAE severity through suppression of either the early peripheral immune or late neuroimmune response. EAE was induced in C57BL/6 mice at two different magnitudes, and peripheral inflammatory and neuroinflammatory responses were measured at days 3, 10, and 18. Th1, Th17, Tc1, Tc17, Tregs, and myeloid derived suppressor cells (MDSC) were identified from the lymph nodes and spleens of each mouse to determine if CBD altered the suppressor cell or inflammatory cell populations in secondary lymphoid tissues. Additionally, neuroinflammation was identified in brain and spinal cord tissues using various immunohistochemical techniques and flow cytometry. Early treatment of EAE with oral CBD reduced clinical disease at the day 18 timepoint which correlated with a significant decrease in the percentage of MOG35–55 specific IFN-γ producing CD8+ T cells in the spleen at day 10. Analysis of both T cell infiltration and lesion size within the spinal cord also showed a moderate reduction in neuroinflammation within the central nervous system (CNS). These results provide evidence that oral CBD suppressed the peripheral immune response that precedes neuroinflammation; however, analysis of the neuroinflammatory endpoints also suggest that the modest reduction in neuroinflammation was only partially responsible for CBD’s neuroprotective capability.

Stress Enhances Proinflammatory Platelet Activity: the Impact of Acute and Chronic Mental Stress

Abstract: The role of platelets in hemostasis and thrombosis has long been recognized, recently their contribution to immunological and inflammatory processes is emerging. Platelets could be the missing link between cardiovascular disease, chronic stress and depressive symptoms. Both physical and mental stressors cause platelet activation reflected by changes in platelet bioactivity and aggregation. Here we evaluate the proinflammatory platelet response to acute and chronic mental stress. In a prospective study design an acute mental stress test was administered to 55 healthy male participants once without and once in the presence of chronic mental stress. Blood was collected prior to and at three time points following an acute mental stress test (0, 30, 60 min). Platelet proinflammatory activation markers, were assessed using FACS analysis and aggregability was measured in response to ADP or epinephrine using PFA-100. A linear mixed model was used for analysis. Chronic mental stress lead to a significant increase in state anxiety (p < 0.001), depressive symptoms (p = 0.045) and perceived stress (p = 0.001). The factor “chronic mental stress” was significantly associated with increased numbers of CD63+ platelets (p = 0.009). The factor “acute mental stress” was associated with alterations in CD62P+ platelets (p < 0.001), CD63+ platelets (p = 0.011), PAC-1+ platelets (p < 0.001) as well as platelet leucocyte aggregates (p = 0.019). The recovery of CD62P function following the acute mental stress exposure was significantly impaired by chronic stress (p = 0.023). Aggregation was affected by chronic and acute mental stress. In conclusion, mental stress is linked to an increased and prolonged proinflammatory platelet bioactivity. This proinflammatory and immunomodulatory stimuli could help to explain the link between mental and somatic disorders.

Combined 1-Deoxynojirimycin and Ibuprofen Treatment Decreases Microglial Activation, Phagocytosis and Dopaminergic Degeneration in MPTP-Treated Mice

Abstract: Inflammation is a predominant aspect of neurodegenerative diseases and experimental studies performed in animal models of Parkinson's disease (PD) suggesting that a sustained neuroinflammation exacerbates the nigrostriatal degeneration pathway. The central role of microglia in neuroinflammation has been studied as a target for potential neuroprotective drugs for PD, for example nonsteroidal anti-inflammatory drugs (NSAIDs) and matrix metalloproteinases (MMP) inhibitors that regulates microglial activation and migration. The aim of this study was to investigate the neuroprotective response of the iminosugar 1-deoxynojirimycin (1-DNJ) and compare its effect with a combined treatment with ibuprofen. MPTP-treated mice were orally dosed with ibuprofen and/or 1-DNJ 1. Open-field test was used to evaluate behavioral changes. Immunohistochemistry for dopaminergic neurons marker (TH+) and microglia markers (Iba-1+; CD68+) were used to investigate neuronal integrity and microglial activation in the substantia nigra pars compacta (SNpc). The pro-inflammatory cytokines TNF-α and IL-6 were analysed by qPCR. Treatments with either 1-DNJ or Ibuprofen alone did not reduce the damage induced by MPTP intoxication. However, combined treatment with 1-DNJ and ibuprofen prevents loss of mesencephalic dopaminergic neurons, decreases the number of CD68+/ Iba-1+ cells, the microglia/neurons interactions, and the pro-inflammatory cytokines, and improves behavioral changes when compared with MPTP-treated animals. In conclusion, these data demonstrate that the combined treatment with a MMPs inhibitor (1-DNJ) plus an anti-inflammatory drug (ibuprofen) has neuroprotective effects open for future therapeutic interventions. Graphical Abstract MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is a protoxicant that, after crossing the Blood Brain Barrier, is metabolized by astrocytic MAO-B to MPDP+, a pyridinium intermediate, which undergoes further two-electron oxidation to yield the toxic metabolite MPP+ (methyl-phenyltetrahydropyridinium) that is then selectively transported into nigral neurons via the mesencephalic dopamine transporter. In this study, we demonstrated that MPTP induced death of dopaminergic neurons, microgliosis, increase of gliapses, motor impairment and neuroinflammation in mice, which were inhibited by combined 1-deoxynojirimycin and ibuprofen treatment.

Antibodies from Multiple Sclerosis Brain Identified Epstein-Barr Virus Nuclear Antigen 1 & 2 Epitopes which Are Recognized by Oligoclonal Bands.

Abstract: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS), the etiology of which is poorly understood. The most common laboratory abnormality associated with MS is increased intrathecal immunoglobulin G (IgG) synthesis and the presence of oligoclonal bands (OCBs) in the brain and cerebrospinal fluid (CSF). However, the major antigenic targets of these antibody responses are unknown. The risk of MS is increased after infectious mononucleosis (IM) due to EBV infection, and MS patients have higher serum titers of anti-EBV antibodies than control populations. Our goal was to identify disease-relevant epitopes of IgG antibodies in MS; to do so, we screened phage-displayed random peptide libraries (12-mer) with total IgG antibodies purified from the brain of a patient with acute MS. We identified and characterized the phage peptides for binding specificity to intrathecal IgG from patients with MS and from controls by ELISA, phage-mediated Immuno-PCR, and isoelectric focusing. We identified two phage peptides that share sequence homologies with EBV nuclear antigens 1 and 2 (EBNA1 and EBNA2), respectively. The specificity of the EBV epitopes found by panning with MS brain IgG was confirmed by ELISA and competitive inhibition assays. Using a highly sensitive phage-mediated immuno-PCR assay, we determined specific bindings of the two EBV epitopes to IgG from CSF from 46 MS and 5 inflammatory control (IC) patients. MS CSF IgG have significantly higher bindings to EBNA1 epitope than to EBNA2 epitope, whereas EBNA1 and EBNA2 did not significantly differ in binding to IC CSF IgG. Further, the EBNA1 epitope was recognized by OCBs from multiple MS CSF as shown in blotting assays with samples separated by isoelectric focusing. The EBNA1 epitope is reactive to MS intrathecal antibodies corresponding to oligoclonal bands. This reinforces the potential role of EBV in the etiology of MS. Graphical abstract Antibodies purified from an MS brain plaque were panned by phage display peptide libraries to discern potential antigens. Phage displaying peptide sequences resembling Epstein-Barr Virus Nuclear Antigens 1 & 2 (EBNA1 & 2) epitopes were identified. Antibodies from sera and CSF from other MS patients also reacted to those epitopes. Antibodies purified from an MS brain plaque were panned by phage display peptide libraries to discern potential antigens. Phage displaying peptide sequences resembling Epstein-Barr Virus Nuclear Antigens 1 & 2 (EBNA1 & 2) epitopes were identified. Antibodies from sera and CSF from other MS patients also reacted to those epitopes.

Reactive Oxygen Species (ROS) are Critical for Morphine Exacerbation of HIV-1 gp120-Induced Pain.

Abstract: Many HIV patients develop chronic pain and use opioid-derived medicine as primary analgesics. Emerging clinical evidence suggests that chronic use of opioid analgesics paradoxically heightens pain states in patients. This side effect of opioid analgesics has a significant negative impact on clinical practice, but the underlying pathogenic mechanism remains elusive. Using a mouse model of HIV-associated pain, we simulated the development of morphine exacerbation on pain and investigated potential underlying cellular and molecular pathways. We found that repeated morphine treatment promoted astrocyte activation in the spinal dorsal horn (SDH) and up-regulation of pro-inflammatory cytokines IL-1β and TNF-α. Furthermore, we observed that morphine administration potentiated mitochondrial reactive oxygen species (ROS) in the SDH of the HIV pain model, especially on astrocytes. Systemic application of the ROS scavenger phenyl-N-t-butyl nitrone (PBN) not only blocked the enhancement of gp120-induced hyperalgesia by morphine but also astrocytic activation and cytokine up-regulation. These findings suggest a critical role of ROS in mediating the exacerbation of gp120-induced pain by morphine. Graphical abstract.

The far-reaching HAND of cART: cART effects on astrocytes

Abstract: Following the introduction of combination antiretroviral therapy (cART), the morbidity and mortality from human immunodeficiency virus (HIV) infection has been drastically curtailed and HIV has now become a chronic manageable disease. Persons living with HIV (PLWH) are living longer and experiencing significant co-morbidities and conditions of aging. NeuroHIV, clinically defined as HIV-Associated Neurocognitive Disorders (HAND) and pathologically manifested by persistent inflammation in the CNS despite cART, is a significant co-morbid condition for PLWH. In the pre-cART era, HIV mediated much of the pathogenesis in the Central Nervous System (CNS); in the cART era, with low to undetectable viremia, other mechanisms may be contributing to persistent neuroinflammation. Emerging data point to the adverse effects at the cellular level of cART, independent of HIV. Astrocytes are the most abundant cells in the CNS, playing vital roles in maintaining CNS homeostasis (e.g. metabolic support to neurons, clearance of neurotransmitters, ion balance, modulation of synaptic functions and maintaining the structural integrity of the blood brain barrier (BBB). Therefore, any disruption of their function will have wide repercussions in the CNS. In this review, we will address current knowledge and gaps on the impact of antiretrovirals (ARVs) on astrocytes and physiologic consequences in the CNS. Understanding the status of this field, will provide a practical framework to elucidate the potential role of cART-mediated dysregulation of astrocytes in neuroHIV pathogenesis and inform therapeutic strategies that are "neuro-friendly". Graphical abstract CNS-penetrating cART have the potential to cause resting astrocytes to become activated into an A1 or neurotoxic phenotype. These cells can in turn secrete inflammatory cytokines that affect surrounding microglia macrophages, as well as neurotoxic factors that impact nearby neurons. In addition, impairment in the physiologic functions of astrocytes will result in altered BBB permeability and disrupted metabolic homeostasis. CNS=Central Nervous System; cART=combined antiretroviral therapy; BBB=blood brain barrier.

Neuroprotective Effect of Phthalide Derivative CD21 against Ischemic Brain Injury:Involvement of MSR1 Mediated DAMP peroxiredoxin1 Clearance and TLR4 Signaling Inhibition.

Abstract: The macrophage scavenger receptor 1 (MSR1)-induced resolution of neuroinflammation may be a novel therapeutic strategy for ischemic stroke. Our previous study showed that the neuroprotective and anti-inflammatory effects of phthalide are associated with the inhibition of the post-ischemic damage-associated molecular pattern (DAMP)/Toll-like receptor 4 (TLR4) pathway. This study investigated the effects of the phthalide derivative CD21 on ischemic brain injury and the mechanism underlying MSR1-induced resolution of neuroinflammation. Using a rat model of 2 h transient middle cerebral artery occlusion (MCAO), MSR1-induced peroxiredoxin1 (PRX1) clearance in RAW264.7 macrophages were investigated. We show here that CD21 significantly ameliorated infarct volumes and neurological deficits in a dose-dependent manner with a ≥ 12 h therapeutic time window. Moreover, administration of 5 mg/kg/day CD21 over 24 h significantly reduced pathological damages, with associated inhibition of PRX1 expression, reduced TLR4/nuclear factor-κB activation and the suppression of the inflammatory response in MCAO rats. Furthermore, the expression of MAFB/MSR1 in the ischemic brain was elevated and the phagocytosis of PRX1 in CD68-positive macrophages isolated from the ischemic brain was enhanced. Further in vitro studies show that CD21 (20 μM) strongly enhanced the Msr1 mRNA and MSR1 protein levers in RAW264.7 cells and PRX1 internalization in cellular lysosomes, which were significantly reversed by N-acetylcysteine treatment. These results suggest that CD21 may exert neuroprotective and anti-inflammatory effects with a wide time window for the treatment of ischemic stroke. The anti-stroke effects of CD21 appear to be mediated partially via the induction of MSR1-promoted DAMP (PRX1) clearance, TLR4/nuclear factor-κB pathway inhibition, and the resolution of inflammation.

Purinergic Signaling of ATP in COVID-19 Associated Guillain-Barré Syndrome.

Abstract: Declared as a global public health emergency, coronavirus disease 2019 (COVID-19) is presented as a disease of the respiratory tract, although severe cases can affect the entire organism. Several studies have shown neurological symptoms, ranging from dizziness and loss of consciousness to cerebrovascular and neurodegenerative diseases. In this context, Guillain-Barre syndrome, an immune-mediated inflammatory neuropathy, has been closely associated with critical cases of infection with "severe acute respiratory syndrome of coronavirus 2" (SARS-CoV-2), the etiological agent of COVID-19. Its pathophysiology is related to a generalized inflammation that affects the nervous system, but neurotropism was also revealed by the new coronavirus, which may increase the risk of neurological sequel, as well as the mortality of the disease. Thus, considering the comorbidities that SARS-CoV-2 infection can promote, the modulation of purinergic signaling can be applied as a potential therapy. In this perspective, given the role of adenosine triphosphate (ATP) in neural intercommunication, the P2X7 receptor (P2X7R) acts on microglia cells and its inhibition may be able to reduce the inflammatory condition of neurodegenerative diseases. Finally, alternative measures to circumvent the reality of the COVID-19 pandemic need to be considered, given the severity of critical cases and the viral involvement of multiple organs.

Antiretroviral Drugs Promote Amyloidogenesis by De-Acidifying Endolysosomes.

Abstract: Antiretroviral therapeutics (ART) have effectively increased the long-term survival of HIV-1 infected individuals. However, the prevalence of HIV-1 associated neurocognitive disorders (HAND) has increased and so too have clinical manifestations and pathological features of Alzheimer’s disease (AD) in people living with HIV-1/AIDS. Although underlying mechanisms are not clear, chronic exposure to ART drugs has been implicated in the development of AD-like symptoms and pathology. ART drugs are categorized according to their mechanism of action in controlling HIV-1 levels. All ART drugs are organic compounds that can be classified as being either weak acids or weak bases, and these physicochemical properties may be of central importance to ART drug-induced AD-like pathology because weak bases accumulate in endolysosomes, weak bases can de-acidify endolysosomes where amyloidogenesis occurs, and endolysosome de-acidification increases amyloid beta (Aβ) protein production and decreases Aβ degradation. Here, we investigated the effects of ART drugs on endolysosome pH and Aβ levels in rat primary cultured neurons. ART drugs that de-acidified endolysosomes increased Aβ levels, whereas those that acidified endolysosomes decreased Aβ levels. Acidification of endolysosomes with the mucolipin transient receptor potential (TRPML) channel agonist ML-SA1 blocked ART drug-induced increases in Aβ levels. Further, ART drug-induced endolysosome de-acidification increased endolysosome sizes; effects that were blocked by ML-SA1-induced endolysosome acidification. These results suggest that ART drug-induced endolysosome de-acidification plays an important role in ART drug-induced amyloidogenesis and that endolysosome acidification might attenuate AD-like pathology in HIV-1 positive people taking ART drugs that de-acidify endolysosomes.

Brain Selective Estrogen Treatment Protects Dopaminergic Neurons and Preserves Behavioral Function in MPTP-induced Mouse Model of Parkinson's Disease.

Abstract: Parkinson’s disease (PD) is characterized by progressive degeneration of dopaminergic neurons in the substantia nigra and loss of both motor and non-motor features. Several clinical and preclinical studies have provided evidence that estrogen therapy reduces the risk of PD but have limitations in terms of adverse peripheral effects. Therefore, we examined the potential beneficial effects of the brain-selective estrogen prodrug, 10β, 17β-dihydroxyestra-1,4-dien-3-one (DHED) on nigrostriatal dopaminergic neurodegeneration and behavioral abnormalities in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. Wild-type mice were treated with daily subcutaneous injections of DHED (50 and 100 µg/kg) or vehicle for four weeks. To produce PD-like symptoms, mice were injected with MPTP (18 mg/kg in saline; intraperitoneally) four times at 2-hr intervals for one day. After behavioral examination, mice were sacrificed, and the brains were isolated for neurochemical and morphological examinations. MPTP injected mice exhibited loss of dopaminergic neurons and fibers in substantia nigra and striatum respectively, along with impaired motor function at day 7 post MPTP injection. These phenotypes were associated with significantly increased oxidative stress and inflammatory responses in the striatum regions. DHED treatments significantly mitigated behavioral impairments and dopaminergic neurodegeneration induced by MPTP. We further observed that DHED treatment suppressed oxidative stress and inflammation in the striatum of MPTP treated mice when compared to vehicle treated mice. In conclusions, our findings suggest that DHED protects dopaminergic neurons from MPTP toxicity in mouse model of PD and support a beneficial effect of brain-selective estrogen in attenuating neurodegeneration and motor symptoms in PD-related neurological disorders.

Protease Inhibitors, Saquinavir and Darunavir, Inhibit Oligodendrocyte Maturation: Implications for Lysosomal Stress

Abstract: Despite the introduction of antiretroviral (ARV) therapy (ART), approximately 30-50% of people living with human immunodeficiency virus-1 (HIV-1) will develop a spectrum of measurable neurocognitive dysfunction, collectively called HIV-associated neurocognitive disorder (HAND). While the clinical manifestations of HAND have changed with the advent of ART, certain pathological features have endured, including white matter alterations and dysfunction. The persistence of white matter alterations in the post-ART era suggests that ARV drugs themselves may contribute to HAND pathology. Our group has previously demonstrated that two ARV compounds from the protease inhibitor (PI) class, ritonavir and lopinavir, inhibit oligodendrocyte maturation and myelin protein production. We hypothesized that other members of the PI class, saquinavir and darunavir, could also negatively impact oligodendrocyte differentiation. Here we demonstrate that treating primary rat oligodendrocyte precursor cells with therapeutically relevant concentrations of either ARV drug results in a concentration-dependent inhibition of oligodendrocyte maturation in vitro. Furthermore, we show that acidifying endolysosomal pH via a mucolipin transient receptor potential channel 1 (TRPML1) agonist provides protection against saquinavir- and darunavir-induced inhibition of oligodendrocyte maturation. Moreover, our findings suggest, for the first time, an imperative role of proper endolysosomal pH in regulating OL differentation, and that therapeutic targeting of endolysosomes may provide protection against ARV-induced oligodendrocyte dysregulation. Graphical Abstract Treatment of primary rat oligodendrocyte precursor cells with therapeutically relevant concentrations of either antiretroviral compound of the protease inhibitor class, darunavir or saquinavir, results in a concentration-dependent inhibition of oligodendrocyte maturation in vitro. Additionally, in darunavir or saquinavir-treated cultures we observed a concentration-dependent decrease in the number of acidic lysosomes, via immunostaining with LysoTracker Red, compared with vehicle-treated cultures. Finally, we showed that acidifying endolysosomal pH via a mucolipin transient receptor potential channel 1 (TRPML1) agonist provides protection against saquinavir- or darunavir-induced inhibition of oligodendrocyte maturation. Our findings suggest, for the first time, a critical role of proper endolysosomal pH in regulating OL differentation, and that therapeutic targeting of endolysosomes may provide protection against antiretroviral-induced oligodendrocyte dysregulation.

Effects of Orally Administered Cannabidiol on Neuroinflammation and Intestinal Inflammation in the Attenuation of Experimental Autoimmune Encephalomyelitis.

Abstract: Cannabidiol (CBD) is a bioactive compound isolated from Cannabis plants that has garnered attention within the medical community due to its potent anti-inflammatory properties. To better understand how CBD limits excessive neuroinflammation we administered CBD via oral gavage (20 mg/kg) in a murine model of multiple sclerosis (MS) known as experimental autoimmune encephalomyelitis (EAE). Using single cell RNA sequencing (scRNA Seq) and array-based transcriptomics we were able to delineate how CBD limits excessive inflammation within the central nervous system (CNS) as well as within the intestinal lining in EAE. In-depth scRNA Seq analysis of CNS tissue demonstrated that CBD treatment resulted in a significant reduction in CXCL9, CXCL10 and IL-1β expression within the CNS, leading to inhibited infiltration of inflammatory macrophages. CBD inhibited IL-1β production independent of the classical cannabinoid receptors, CB1 and CB2. CBD treatment also led to induction of Myeloid-derived Suppressor Cells (MDSCs) both in the CNS and periphery. Interestingly, CBD treatment of EAE mice revealed significant suppression of inflammation in the gastrointestinal (GI) tract. The intestinal epithelial cells (IECs) of CBD treated mice demonstrated a transcriptional inhibition of a family of pyroptosis initiators that drive localized inflammation known as gasdermins (GSDMs). Further investigation into the GI tract via 16s sequencing of cecal and fecal contents demonstrated that oral administration of CBD resulted in no significant changes in the intestinal microbiota composition. These findings demonstrate the beneficial effect of CBD treatment on autoimmune neuroinflammation by ablating expression of pro-inflammatory chemoattractants, regulating inflammatory macrophage activity, promoting MDSC expansion, and limiting the systemic low-grade inflammation in the GI tract, culminating in the attenuation of EAE.

Repurposing of Tetracyclines for COVID-19 Neurological and Neuropsychiatric Manifestations: A Valid Option to Control SARS-CoV-2-Associated Neuroinflammation?

Abstract: The recent outbreak of coronavirus disease 2019 (COVID-19) has gained considerable attention worldwide due to its increased potential to spread and infect the general population. COVID-19 primarily targets the human respiratory epithelium but also has neuro-invasive potential. Indeed, neuropsychiatric manifestations, such as fatigue, febrile seizures, psychiatric symptoms, and delirium, are consistently observed in COVID-19. The neurobiological basis of neuropsychiatric COVID-19 symptoms is not fully understood. However, previous evidence about systemic viral infections pointed to an ongoing neuroinflammatory response to viral antigens and proinflammatory mediators/immune cells from the periphery. Microglia cells mediate the overproduction of inflammatory cytokines, free radicals, and damage signals, culminating with neurotoxic consequences. Semi-synthetic second-generation tetracyclines, including minocycline (MINO) and doxycycline (DOXY), are safe bacteriostatic agents that have remarkable neuroprotective and anti-inflammatory properties. Promising results have been obtained in clinical trials using tetracyclines for major psychiatric disorders, such as schizophrenia and major depression. Tetracyclines can inhibit microglial reactivity and neuroinflammation by inhibiting nuclear factor kappa B (NF-kB) signaling, cyclooxygenase 2, and matrix metalloproteinases (MMPs). This drug class also has a broad profile of activity against bacteria associated with community-based pneumonia, including atypical agents. COVID-19 patients are susceptible to secondary bacterial infections, especially those on invasive ventilation. Therefore, we suggest tetracyclines' repurposing as a potential treatment for COVID-19 neuropsychiatric manifestations. These drugs can represent a valuable multi-modal treatment for COVID-19-associated neuroinflammatory alterations based on their broad antimicrobial profile and neuroinflammation control.

STING/NF-κB/IL-6-Mediated Inflammation in Microglia Contributes to Spared Nerve Injury (SNI)-Induced Pain Initiation.

Abstract: Innate immune response acts as the first line of host defense against damage and is initiated following the recognition of pathogen-associated molecular patterns (PAMPs). For double-stranded DNA (dsDNA) sensing, interferon gene stimulator (STING) was discovered to be an integral sensor and could mediate the immune and inflammatory response. Selective STING antagonist C-176 was administered and pain behaviors were assessed following spared nerve injury (SNI)-induced neuropathic pain. The level of serum dsDNA following neuropathic pain was assessed using Elisa analysis. STING signaling pathway, microglia activation, and proinflammatory cytokines were assessed by qPCR, western blots, Elisa, and immunofluorescence staining. STING agonist DMXAA was introduced into BV-2 cells to assess the inflammatory response in microglial cells. dsDNA was significantly increased following SNI and STING/TANK-binding kinase 1 (TBK1)/nuclear factor-kappa B (NF-κB) pathway was activated in vivo and vitro. Early but not the late intrathecal injection of C-176 attenuated SNI-induced pain hypersensitivity, microglia activation, proinflammatory factors, and phosphorylated JAK2/STAT3 in the spinal cord dorsal horn, and the analgesic effect of C-176 was greatly abolished by recombinant IL-6 following SNI. We provided evidence clarifying dsDNA mediated activation of microglia STING signaling pathway, after which promoting expression of proinflammatory cytokines that are required for hyperalgesia initiation in the spinal cord dorsal horn of SNI model. Further analysis showed that microglial STING/TBK1/NF-κB may contribute to pain initiation via IL-6 signaling. Pharmacological blockade of STING may be a promising target in the treatment of initiation of neuropathic pain.