HIV-Associated Neurocognitive Disorder: A Look into Cellular and Molecular Pathology.

Despite combined antiretroviral therapy (cART) limiting HIV replication to undetectable levels in the blood, people living with HIV continue to experience HIV-associated neurocognitive disorder (HAND). HAND is associated with neurocognitive impairment, including motor impairment, and memory loss. HIV has been detected in the brain within 8 days of estimated exposure and the mechanisms for this early entry are being actively studied. Once having entered into the central nervous system (CNS), HIV degrades the blood-brain barrier through the production of its gp120 and Tat proteins. These proteins are directly toxic to endothelial cells and neurons, and propagate inflammatory cytokines by the activation of immune cells and dysregulation of tight junction proteins. The BBB breakdown is associated with the progression of neurocognitive disease. One of the main hurdles for treatment for HAND is the latent pool of cells, which are insensitive to cART and prolong inflammation by harboring the provirus in long-lived cells that can reactivate, causing damage. Multiple strategies are being studied to combat the latent pool and HAND; however, clinically, these approaches have been insufficient and require further revisions. The goal of this paper is to aggregate the known mechanisms and challenges associated with HAND.

Human immunodeficiency virus-1 Tat exerts its neurotoxic effects by downregulating Sonic hedgehog signaling.

We previously showed that HIV-1 can alter the expression of tight junction proteins by downregulating Sonic hedgehog (Shh) signaling, thereby disrupting blood-brain barrier (BBB) integrity. In this study, we employed a conditional, CNS specific, Tat transgenic murine model to investigate if HIV-Tat exerts its neurotoxic effects by downregulating Shh signaling. Results indicate that Tat + mice exhibit significantly reduced expression of Shh and Gli1. HIV-Tat induced downregulation of Shh signaling correlated with disruption of BBB function and induced infiltration of peripheral leukocytes into the brain tissue. Further, our in vivo and in vitro experiments suggest that activation of Shh signaling can rescue detrimental effects of Tat on endothelial function by inducing the expression of junctional proteins and by decreasing the levels of inflammatory cytokines/chemokines.

Seasonal variation of potentially toxic metal contamination in Yamuna riverine ecosystem, Delhi, India.

The River Yamuna in Delhi region, the National Capital Territory (NCT) of India, carries potentially toxic metals such as Cr, Pb, Mn, Mg, Hg, Fe and Zn. These contaminants are discharged mainly from industrial wastes, agricultural and household activities and domestic sewage. A total of 12 stations (2.5 to 3.5 km apart from each other) were selected for the study, covering the upstream and downstream areas of river Yamuna in Delhi. The investigated sites were evaluated for significant difference between upstream and downstream locations of river Yamuna in three different time periods (June, October, February). Metal contamination were measured in water, sediments (2 µm) and nearby agriculture soil of the river Yamuna, and found with high metal loads as compared with the international standards, chiefly in the downstream sites as the river flows through the Delhi stretch. The multivariate statistical analysis revealed spatial and temporal variations in the metal concentrations which suggest seasonal variation and common point source of some metals while different sources of other metals. The contamination of the river water and adjoining agriculture soils points towards possible entry of these metals into the food chain. The study indicates that considering the current status of metal pollution, the surface water is not in good conditions for use as drinking purpose because of the high concentrations of few potentially toxic metals. Our study recommends regular monitoring of toxic metals in Yamuna river water and sediments, strict ban on the domestic, agriculture and industrial waste disposal for the restoration of the river to its natural state.

Blocked transcription through KvDMR1 results in absence of methylation and gene silencing resembling Beckwith-Wiedemann syndrome.

The maternally methylated KvDMR1 ICR regulates imprinted expression of a cluster of maternally expressed genes on human chromosome 11p15.5. Disruption of imprinting leads to Beckwith-Wiedemann syndrome (BWS), an overgrowth and cancer predisposition condition. In the majority of individuals with BWS, maternal-specific methylation at KvDMR1 is absent and genes under its control are repressed. We analyzed a mouse model carrying a poly(A) truncation cassette inserted to prevent RNA transcripts from elongation through KvDMR1. Maternal inheritance of this mutation resulted in absence of DNA methylation at KvDMR1, which led to biallelic expression of Kcnq1ot1 and suppression of maternally expressed genes. This study provides further evidence that transcription is required for establishment of methylation at maternal gametic DMRs. More importantly, this mouse model recapitulates the molecular phenotypic characteristics of the most common form of BWS, including loss of methylation at KvDMR1 and biallelic repression of Cdkn1c, suggesting that deficiency of maternal transcription through KvDMR1 may be an underlying cause of some BWS cases.

Preventive and therapeutic challenges in combating Zika virus infection: are we getting any closer?

The neuroteratogenic nature of Zika Virus (ZIKV) infection has converted what would have been a tropical disease into a global threat. Zika is transmitted vertically via infected placental cells especially in the first and second trimesters. In the developing central nervous system (CNS), ZIKV can infect and induce apoptosis of neural progenitor cells subsequently causing microcephaly as well as other neuronal complications in infants. Its ability to infect multiple cell types (placental, dermal, and neural) and increased environmental stability as compared to other flaviviruses (FVs) has broadened the transmission routes for ZIKV infection from vector-mediated to transmitted via body fluids. To further complicate the matters, it is genetically similar (about 40%) with the four serotypes of dengue virus (DENV), so much so that it can almost be called a fifth DENV serotype. This homology poses the risk of causing cross-reactive immune responses and subsequent antibody-dependent enhancement (ADE) of infection in case of secondary infections or for immunized individuals. All of these factors complicate the development of a single preventive vaccine candidate or a pharmacological intervention that will completely eliminate or cure ZIKV infection. We discuss all of these factors in detail in this review and conclude that a combinatorial approach including immunization and treatment might prove to be the winning strategy.

Rhizoremediation of cadmium-contaminated soil associated with hydroxamate siderophores isolated from Cd-resistant plant growth-promoting Dietzia maris and Lysinibacillus strains.

In search of multitrait plant growth-promoting (PGP) inoculants, we introduced two cadmium-resistant bacterial strains, C4 (PG), C5 (WB), and their consortium C6 (PG × WB) isolated from metal-contaminated industrial waste-fed canal near West Bengal. The test isolates were biochemically characterized and screened in vitro for siderophore production. The infrared spectra revealed the hydroxamate nature of the siderophore produced. Further in green house, siderophore-based seed inoculation with selected PGP isolates exhibited stimulatory effects on seed germination (up to 85.4%), chlorophyll index (22.9 spad unit), shoot and root length (70% and 62.7%), tiller numbers (38.82%), spikelet numbers (52.2%), straw yield (62.2%), grain yield (76.1%), total dry matter of root and shoot (55.56% and 64.4%, respectively), and grain yields (76.1%) of tested wheat cultivars. The 16S rRNA sequencing identified strain PG and WB as Dietzia maris and Lysinibacillus sp. strains. Furthermore, inoculation of C6 (consortium) in both cultivar UP-2565 and KS-227 showed maximum Cd sorption capacity in roots (38.3% and 67.1%) and shoots (68.4% and 67.5%), respectively. Both the strains and their consortium showed a great potential to increase the growth and yield of wheat cultivars, which can also be utilized for rhizoremediation process.

Characterization of platelet-monocyte complexes in HIV-1-infected individuals: possible role in HIV-associated neuroinflammation.

HIV-1-associated neuroinflammation persists even with effective combined antiretroviral therapy, and it is associated with the presence of activated monocytes/macrophages within the CNS. To infiltrate the CNS, monocytes transmigrate across the selectively permeable blood-brain barrier, which is compromised during HIV-1 infection. Interestingly, platelet-derived excess soluble CD40 ligand found in the plasma and cerebrospinal fluid of HIV-1-infected individuals with cognitive impairment has previously been implicated in increased blood-brain barrier permeability. In this study we show that soluble CD40 ligand also promotes the formation of complexes between inflammatory monocytes and activated platelets (PMCs), which are detected by flow cytometry as monocytes that express excess of CD61, a platelet marker, and that these complexes are increased in individuals with HIV-1 infection. PMCs exhibit an enhanced ability to adhere to human brain microvascular endothelial cells as compared with monocytes alone, and they migrate across the transendothelial barrier. These complexes can be found marginalized in the lumen of postcapillary venules in postmortem brain tissue derived from cases of HIV-1-associated encephalitis. The extravasation of monocytes across the brain endothelium may exacerbate neuroinflammation, indicating that enhancing this event via platelet interaction may be a contributing factor in the development of cognitive impairment. Thus, dampening platelet activation, and in turn PMC formation, with antiplatelet agents may prove beneficial in developing adjunctive therapies for use in combination with combined antiretroviral therapy in an effort to reduce HIV-1-associated neurologic deficit.

Investigating the role of ankyrin-rich membrane spanning protein in human immunodeficiency virus type-1 Tat-induced microglia activation.

Long-term persistence of human immunodeficiency virus type-1 (HIV) in the central nervous system (CNS) results in mild to severe neurocognitive impairment in a significant proportion of the HIV-infected population. These neurological deficits are known as HIV-associated neurocognitive disorders (HAND). Microglia are CNS-resident immune cells that are directly infected by HIV and consequently secrete proinflammatory molecules that contribute to HIV-induced neuroinflammation. Indeed, the number of activated macrophage and microglia in the brain is more highly correlated with cognitive impairment than the amount of neuronal apoptosis. Ankyrin-rich membrane spanning protein (ARMS/Kidins220) is a multidomain transmembrane protein that is involved with neurotrophin signaling in the CNS. We have previously established the role of ARMS in mediating neuronal survival via a neurotrophin-dependent mechanism. Recent reports also have suggested that ARMS is involved with cell signaling in multiple immune cell types. In this study, we aim to investigate the role of ARMS in HIV Tat-mediated microglial cell activation by employing in vitro methods. Following ARMS depletion by a lentivirus encoding ARMS-specific short hairpin RNA (shRNA), we observed a marked reduction in the HIV Tat-induced proinflammatory response, associated with loss of tumor necrosis factor alpha production and nuclear factor-kappa B (NF-κB) activation. Furthermore, co-immunoprecipitation studies suggested that ARMS physically interacts with inhibitory kappa B kinase subunits in order to facilitate NF-κB activation. Our results establish the role of ARMS in microglial activation by HIV Tat and warrant additional studies to better understand these molecular mechanisms, which may uncover novel therapeutic targets for the treatment of HAND.

Sulforaphane prevents the reactivation of HIV-1 by suppressing NFκB signaling.

Despite more than 20 years of combination antiretroviral therapy (cART), complete eradication of HIV remains a daunting task. While cART has been very effective in limiting new cycles of infection and keeping viral load below detectable levels with partial restoration of immune functions, it cannot provide a cure. Evidently, the interruption of cART leads to a quick rebound of the viral load within a few weeks. These consistent observations have revealed HIV ability to persist as an undetectable latent reservoir in a variety of tissues that remain insensitive to antiretroviral therapies. The 'Block-and-Lock' approach to drive latent cells into deep latency has emerged as a viable strategy to achieve a functional cure. It entails the development of latency-promoting agents with anti-HIV functions. Recent reports have suggested sulforaphane (SFN), an inducer of NRF-2 (nuclear erythroid 2-related factor 2)-mediated antioxidative signaling, to possess anti-HIV properties by restricting HIV replication at the early stages. However, the effect of SFN on the expression of integrated provirus remains unexplored. We have hypothesized that SFN may promote latency and prevent reactivation. Our results indicate that SFN can render latently infected monocytes and CD4+ T cells resistant to reactivation. SFN treatments antagonized the effects of known latency reactivating agents, tumor necrosis pactor (TNF-α), and phorbol 12-myristate 13-acetate (PMA), and caused a significant reduction in HIV transcription, viral RNA copies, and p24 levels. Furthermore, this block of reactivation was found to be mediated by SFN-induced NRF-2 signaling that specifically decreased the activation of NFκB signaling and thus restricted the HIV-1 promoter (5'LTR) activity. Overall, our study provides compelling evidence to highlight the latency-promoting potential of SFN which could be used in the 'Block-and-Lock' approach to achieve an HIV cure.

Initiation of combined antiretroviral therapy confers suboptimal beneficial effects on neurovascular function in people with HIV.

Introduction: Due to advances in combined anti-retroviral treatment (cART), there is an increased burden of age-related cerebrovascular disease (CBVD), in people living with HIV (PWH). The underlying CNS injury can be assessed by measuring cerebral blood flow (CBF) and cerebrovascular reactivity (CVR). Methods: 35 treatment-naïve PWH and 53 HIV negative controls (HC) were enrolled in this study. Study participants underwent T1-weighted anatomical, pseudo-continuous arterial spin labeling, and resting-state functional MRI to obtain measures of CBF and CVR prior to starting cART treatment and at two-time points (12 weeks and 2 years) post-cART initiation. Controls were scanned at the baseline and 2-year visits. We also measured plasma levels of microparticles of endothelial and glial origin and well-known endothelial inflammation markers, ICAM-1 and VCAM-1, to assess HIV-associated endothelial inflammation and the interaction of these peripheral markers with brain neurovascular function. Results: HIV infection was found to be associated with reduced CVR and increased levels of endothelial and glial microparticles (MPs) prior to initiation of cART. Further, CVR correlated negatively with peripheral MP levels in PWH. Discussion: Our results suggest that while cART treatment has a beneficial effect on the neurovascular function after initiation, these benefits are suboptimal over time.

Complete genome sequences of Gordonia rubripertincta phages OtterstedtS21 and Patos.

We report the genomes of two viruses with siphovirus morphology, OtterstedtS21 and Patos, from Albany, New York, using Gordonia rubripertincta. The genomes of OtterstedtS21 and Patos are ~68 kbp long with 58% GC content. Both phages group with cluster DV based on gene content similarity to phages in the Actinobacteriophage database.

Monocytes complexed to platelets differentiate into functionally deficient dendritic cells.

In addition to their role in hemostasis, platelets store numerous immunoregulatory molecules such as CD40L, TGFß, ß2-microglobulin, and IL-1ß and release them upon activation. Previous studies indicate that activated platelets form transient complexes with monocytes, especially in HIV infected individuals and induce a proinflammatory monocyte phenotype. Because monocytes can act as precursors of dendritic cells (DCs) during infection/inflammation as well as for generation of DC-based vaccine therapies, we evaluated the impact of activated platelets on monocyte differentiation into DCs. We observed that in vitro cultured DCs derived from platelet-monocyte complexes (PMCs) exhibit reduced levels of molecules critical to DC function (CD206, dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin, CD80, CD86, CCR7) and reduced antigen uptake capacity. DCs derived from PMCs also showed reduced ability to activate naïve CD4+ and CD8+ T cells, and secrete IL-12p70 in response to CD40L stimulation, resulting in decreased ability to promote type-1 immune responses to HIV antigens. Our results indicate that formation of complexes with activated platelets can suppress the development of functional DCs from such monocytes. Disruption of PMCs in vivo via antiplatelet drugs such as Clopidogrel/Prasugrel or the application of platelet-free monocytes for DCs generation in vitro, may be used to enhance immunization and augment the immune control of HIV.

Not Just for Urine: A Versatile Tool for Foreign Body Removal.

The swallowed or aspirated foreign body is a common pediatric emergency medicine complaint for which emergency providers must be familiar with the intricacies of management. Most swallowed foreign bodies will harmlessly pass through the GI tract, but children with GI tract abnormalities may have an increased risk of object impaction. There are few reported cases of foreign object ingestion in children with GI tract abnormalities, specifically ostomies. The Foley catheter is a versatile tool that is easily accessible in the ED setting. We present a novel case of foreign body ingestion in an infant with a colostomy secondary to Hirschsprung's disease managed with Foley catheter retrieval through an ileostomy stoma. A 17-month-old infant presented to the ED with a chief complaint of an episode of bloody vomiting. He had a two-day history of increased irritability and intolerance of feeds with emesis after every feed. The child's medical history is pertinent for Hirschsprung's disease, for which the patient had a pull-through procedure shortly after birth and a revision of the pull-through. On physical examination, the patient's ostomy was found to contain brown-green liquid stool. A small ovular mass was visualized at the stoma during crying episodes. Supine posteroanterior radiograph of the abdomen showed an oval-shaped radiolucency consistent with a metallic ingested foreign body at the site of the stoma. The foreign object was removed using a Foley catheter and forceps and was found to be a penny. The patient was observed and discharged without complications later that day. Treatment of a symptomatic ingested foreign object requires careful consideration of the type of object present and its location in the body. In this case report, we discussed the removal of an ingested coin in a symptomatic 17-month-old infant with a history of ileostomy secondary to Hirschsprung's disease using a Foley catheter. In children with ostomies, prompt imaging and non-surgical removal may be an option to manage retrieval of these objects if the patient is stable and symptoms are not severe.

Altered and Agitated due to Hypertension: A Case of Posterior Reversible Encephalopathy Syndrome.

The authors present a case of posterior reversible encephalopathy syndrome in a patient on nutritional supplements. The presentation and emergency management are discussed.

Intractable nausea and vomiting in naïve ingestion of kratom for analgesia.

BACKGROUND: Kratom is a habit-forming opioid-like substance with an acute toxidrome of various symptoms such as diaphoresis, dizziness, nausea, and vomiting. Chronic users require increasing dosages for the analgesic effects. Although kratom use dates back to the 1800s in Asia, kratom intoxication is still a novel (but increasing) toxidrome in the Western world. Here, we present a novel case of acute toxicity from overdose in a kratom-naïve patient, taking place through recommendation by a family member who chronically takes this substance. CASE PRESENTATION: We present the case of a 62-year-old woman arriving to the emergency department (ED) with a chief complaint of intractable vomiting after ingestion of kratom. After a day of yard work, she was in pain, secondary to her osteoporotic joints. She was recommended kratom from a family member, who stated he was using kratom to transition away from opioid dependence. She took two "scoops." She proceeded to have multiple episodes of vomiting at home. She came to the ED, where she required multiple rounds of anti-emetic medication for resolution of her symptoms. DISCUSSION: We present a classic case of a novel acute toxicity: kratom. A unique aspect of this case is the circumstance by which this toxicity took place: a family member who chronically takes this substance (that requires increasing dosages to remain effective) recommended a dosage to this kratom-naïve patient, leading to overdose. This opioid family alternative substance is gaining popularity across the USA in the era of the opioid crisis. Further documentation of case reports and research is required to learn the associated risks of the use of this substance.

Novel Mechanism of Microvesicle Regulation by the Antiviral Protein Tetherin During HIV Infection.

Background Microvesicles are cell membrane-derived vesicles that have been shown to augment inflammation. Specifically, monocyte-derived microvesicles (MDMVs), which can express the coagulation protein tissue factor, contribute to thrombus formation and cardiovascular disease. People living with HIV experience higher prevalence of cardiovascular disease and also exhibit increased levels of plasma microvesicles. The process of microvesicle release has striking similarity to budding of enveloped viruses. The surface protein tetherin inhibits viral budding by physically tethering budding virus particles to cells. Hence, we investigated the role of tetherin in regulating the release of MDMVs during HIV infection. Methods and Results The plasma of aviremic HIV-infected individuals had increased levels of tissue factor + MDMVs, as measured by flow cytometry, and correlated to reduced tetherin expression on monocytes. Superresolution confocal and electron microscopy showed that tetherin localized at the site of budding MDMVs. Mechanistic studies revealed that the exposure of monocytes to HIV-encoded Tat triggered tetherin loss and subsequent rise in MDMV production. Overexpression of tetherin in monocytes led to morphologic changes in the pseudopodia directly underneath the MDMVs. Further, tetherin knockout mice demonstrated a higher number of circulating MDMVs and less time to bleeding cessation. Conclusions Our studies define a novel regulatory mechanism of MDMV release through tetherin and explore its contribution to the procoagulatory state that is frequently observed in people with HIV. Such insights could lead to improved therapies for individuals infected with HIV and also for those with cardiovascular disease.

Stress-induced overexpression of the heme-regulated eIF-2alpha kinase is regulated by Elk-1 activated through ERK pathway.

The heme-regulated eIF-2alpha kinase, also called the heme-regulated inhibitor (HRI), is activated under various cytoplasmic stresses in reticulocytes leading to inhibition of initiation of protein synthesis. Our previous studies indicated that the promoter activity and expression of the human HRI (hHRI) increase in human K562 cells during heat shock and lead exposure. Contrary to this, hemin chloride which inactivates the kinase, downregulates HRI expression. Here, we attempted to understand the mechanism of regulation of hHRI expression in the lead- and hemin-exposed cells. Our results demonstrate the involvement of two transcription factors, Elk-1 and MZF-1 in regulating HRI expression. Chromatin immunoprecipitation assays established further that Elk-1 is involved in upregulating HRI expression during stress along with a co-activator p300, while MZF-1 along with HDAC-1 is instrumental in its downregulation during hemin treatment. We also demonstrate the involvement of ERK pathway in activating Elk-1 during stress resulting in an over expression of hHRI.

Inhibition of Tropomyosin Receptor Kinase A Signaling Negatively Regulates Megakaryopoiesis and induces Thrombopoiesis.

Neurotrophin signaling modulates the differentiation and function of mature blood cells. The expression of neurotrophin receptors and ligands by hematopoietic and stromal cells of the bone marrow indicates that neurotrophins have the potential to regulate hematopoietic cell fate decisions. This study investigates the role of neurotrophins and Tropomyosin receptor kinases (Trk) in the development of megakaryocytes (MKs) and their progeny cells, platelets. Results indicate that primary human MKs and MK cells lines, DAMI, Meg-01 and MO7e express TrkA, the primary receptor for Nerve Growth Factor (NGF) signaling. Activation of TrkA by NGF enhances the expansion of human MK progenitors (MKPs) and, to some extent, MKs. Whereas, inhibition of TrkA receptor by K252a leads to a 50% reduction in the number of both MKPs and MKs and is associated with a 3-fold increase in the production of platelets. In order to further confirm the role of TrkA signaling in platelet production, TrkA deficient DAMI cells were generated using CRISPR-Cas9 technology. Comparative analysis of wild-type and TrkA-deficient Dami cells revealed that loss of TrkA signaling induced apoptosis of MKs and increased platelet production. Overall, these findings support a novel role for TrkA signaling in platelet production and highlight its potential as therapeutic target for Thrombocytopenia.

Sonic Hedgehog mimetic prevents leukocyte infiltration into the CNS during acute HIV infection.

Infiltration of infected leukocytes culminates in establishment of a brain niche for Human Immunodeficiency Virus (HIV) during acute phase of infection, initiating an ongoing cascade of persistent viral replication and inflammation, that causes irreversible neuronal injury and HIV associated neurocognitive disease (HAND). In this study, humanized mice were treated with Smoothened Agonist (SAG), a Sonic Hedgehog (Shh) mimetic in order to fortify blood brain barrier (BBB) and dampen leukocyte extravasation into CNS during AHI. Results indicate that SAG treatment reduced viral burden in the CNS immediately after HIV transmission, but also conferred extended neuroprotection via increased BBB integrity (elevated levels of tight-junction protein, Claudin 5, and reduced S100B levels in periphery). These mice also showed healthier neurons with thick, uniform dendrites and reduced numbers of activated astrocytes. Additional in vitro experiments suggested SAG treatment was not associated with the establishment or reversal of latency in the target cells. Altogether, these findings validate neuroprotective role of Shh signaling and highlight the therapeutic potential of Shh mimetics against CNS complications associated with HIV infection. Further our results strongly demonstrate that pharmacological interventions to reduce leukocyte mobilization during early HIV infection, can provide prolonged neuroprotection, which might significantly delay the onset of HAND.