The neurovascular units (NVU) are the minimal functional units of the blood–brain barrier (BBB), composed of endothelial cells, pericytes, astrocytes, microglia, neurons, and the basement membrane. The BBB serves as an important interface for immune communication between the brain and peripheral circulation. Disruption of the NVU by the human immunodeficiency virus-1 (HIV-1) induces dysfunction of the BBB and triggers inflammatory responses, which can lead to the development of neurocognitive impairments collectively known as HIV-1-associated neurocognitive disorders (HAND). Methamphetamine (METH) use disorder is a frequent comorbidity among individuals infected with HIV-1. METH use may be associated not only with rapid HIV-1 disease progression but also with accelerated onset and increased severity of HAND. However, the molecular mechanisms of METH-induced neuronal injury and cognitive impairment in the context of HIV-1 infection are poorly understood. In this review, we summarize recent progress in the signaling pathways mediating synergistic impairment of the BBB and neuronal injury induced by METH and HIV-1, potentially accelerating the onset or severity of HAND in HIV-1-positive METH abusers. We also discuss potential therapies to limit neuroinflammation and NVU damage in HIV-1-infected METH abusers.
Inflammation and an increase in antioxidant responses mediated by oxidative stress play an important role in the pathogenesis of acute liver injury (ALI). We utilized in silico prediction of biological activity spectra for substances (PASS) analysis to estimate the potential biological activity profile of deethylated ethoxyquin (DEQ) and hypothesized that DEQ exhibits antioxidant and anti-inflammatory effects in a rat model of carbon tetrachloride (CCl4)-induced ALI. Our results demonstrate that DEQ improved liver function which was indicated by the reduction of histopathological liver changes. Treatment with DEQ reduced CCl4-induced elevation of gene expression, and the activity of antioxidant enzymes (AEs), as well as the expression of transcription factors Nfe2l2 and Nfkb2. Furthermore, DEQ treatment inhibited apoptosis, downregulated gene expression of pro-inflammatory cytokines (Tnf and Il6), cyclooxygenase 2 (Ptgs2), decreased glutathione (GSH) level and myeloperoxidase (MPO) activity in rats with ALI. Notably, DEQ treatment led to an inhibition of CCl4-induced NLRP3-inflammasome activation which was indicated by the reduced protein expression of IL-1β, caspase-1, and NLRP3 in the liver. Our data suggest that DEQ has a hepatoprotective effect mediated by redox-homeostasis regulation, NLRP3 inflammasome, and apoptosis inhibition, which makes that compound a promising candidate for future clinical studies.
Brain endothelial extracellular vesicles carrying amyloid beta (EV-Aβ) can be transferred to neural progenitor cells (NPCs) leading to NPC dysfunction. However, the events involved in this EV-mediated Aβ pathology are unclear. EV-proteomics studies identified Serpine-1 (plasminogen activator inhibitor 1, PAI-1) as a major connecting “hub” on several protein–protein interaction maps. Serpine-1 was described as a key player in Aβ pathology and was linked to HIV-1 infection as well. Therefore, the aim of this work was to address the hypothesis that Serpine-1 can be transferred via EVs from brain endothelial cells (HBMEC) to NPCs and contribute to NPC dysfunction. HBMEC concentrated and released Serpine-1 via EVs, the effect that was potentiated by HIV-1 and Aβ. EVs loaded with Serpine-1 were readily taken up by NPCs, and HIV-1 enhanced this event. Interestingly, a highly specific Serpine-1 inhibitor PAI039 increased EV-Aβ transfer to NPCs in the presence of HIV-1. PAI039 also partially blocked mitochondrial network morphology alterations in the recipient NPCs, which developed mainly after HIV + Aβ-EV transfer. PAI039 partly attenuated HIV-EV-mediated decreased synaptic protein levels in NPCs, while increased synaptic protein levels in NPC projections. These findings contribute to a better understanding of the complex mechanisms underlying EV-Serpine-1 related Aβ pathology in the context of HIV infection. They are relevant to HIV-1 associated neurocognitive disorders (HAND) in an effort to elucidate the mechanisms of neuropathology in HIV infection.
6 October 2022 in Journal of Visualized Experiments
Ischemic stroke is a major cause of death and disability worldwide with limited therapeutic options. The neuropathology of ischemic stroke is characterized by an interruption in blood supply to the brain leading to cell death and cognitive dysfunction. During and after ischemic stroke, blood-brain barrier (BBB) dysfunction facilitates injury progression and contributes to poor patient recovery. Current BBB models primarily include endothelial monocultures and double co-cultures with either astrocytes or pericytes. Such models lack the ability to fully imitate a dynamic brain microenvironment, which is essential for cell-to-cell communication. Additionally, commonly used BBB models often contain immortalized human endothelial cells or animal-derived (rodent, porcine, or bovine) cell cultures that pose translational limitations. This paper describes a novel well-insert-based BBB model containing only primary human cells (brain microvascular endothelial cells, astrocytes, and brain vascular pericytes) enabling the investigation of ischemic brain injury in vitro. The effects of oxygen-glucose deprivation (OGD) on barrier integrity were assessed by passive permeability, transendothelial electrical resistance (TEER) measurements,and direct visualization of hypoxic cells. The presented protocol offers a distinct advantage inmimicking the intercellular environment of the BBB in vivo, serving as a more realistic in vitro BBB model for developing new therapeutic strategies in the setting of ischemic brain injury.
Methamphetamine (METH) use disorder (MUD) is a frequent comorbidity among people with HIV-1 (PWH). While both METH and HIV-1 independently disrupt the brai