Methamphetamine Enhances HIV-Induced Aberrant Proliferation of Neural Progenitor Cells via the FOXO3-Mediated Mechanism

Impaired olfactory bulb neurogenesis mediated by Notch1 contributes to olfactory dysfunction in mice chronically exposed to methamphetamine

Methamphetamine (Meth) is a potent central nervous system stimulant with high addictive potential and neurotoxic effects. Chronic use results in significant damage in various brain functions, including cognition, memory, and sensory perception. Olfactory dysfunction is a notable yet often overlooked consequence of Meth abuse, and its underlying mechanisms are not fully understood. This study investigates the mechanisms of Meth-induced olfactory impairment through a thorough examination of olfactory bulb (OB) neurogenesis. We found that chronic Meth abuse impaired olfactory function in mice by not only reducing the self-renewal of subventricular zone (SVZ) neural stem cells (NSCs) but also altering their differentiation potential, leading their differentiation into astrocytes at the expense of neurons. Mechanistically, Meth inhibits autophagosome-lysosome fusion by downregulating Syntaxin 17 (Stx17), which reduces autophagic flux. In NSCs, autophagy tightly regulates Notch1 levels, and impaired autophagic degradation of Notch1 leads to its abnormal activation. This alters NSCs fate determination, ultimately affecting OB neurogenesis. Our study reveals that Meth impairs olfactory function through autophagic dysfunction and aberrant Notch1 signaling. Understanding these mechanisms not only provides new insights into Meth-induced olfactory dysfunction but also offers potential targets for developing therapies to alleviate Meth-induced neurotoxicity and sensory damage in the future.

Identification of aberrant plasma vesicles containing AAK1 and CCDC18-AS1 in adolescents with major depressive disorder and preliminary exploration of treatment efficacy

BACKGROUND

Major depressive disorder (MDD) during adolescence significantly jeopardizes both mental and physical health. However, the etiology underlying MDD in adolescents remains unclear.

METHODS

A total of 74 adolescents with MDD and 40 health controls (HCs) who underwent comprehensive clinical and cognitive assessments were enrolled. Differential expression analysis was conducted on plasma extracellular vesicles (EVs) carrying long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) by microarray analysis. Two possible lncRNA-miR-mRNA networks were established and candidate regulatory axes were generated using the StarBase, miRDB, and TargetScan bioinformatics databases. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the candidate molecules and signaling axes in a clinical cohort.

RESULTS

A total of 3752 dysregulated lncRNAs and 1789 dysfunctional mRNAs were identified. Two candidate regulatory axes (AC156455.1/miR-126-5p/AAK1 and CCDC18-AS1/miR-6835-5p/CCND2) with potential connections with MDD were selected. The candidate molecules exhibit differential expression patterns among adolescents with MDD and HCs, as well as before and after treatment with sertraline in adolescents with MDD. Furthermore, AAK1, CCDC18-AS1, and miR-6835-5p expressions exhibited significant differences between the response and non-response groups. Baseline expression of CCDC18-AS1, miR-6835-5p, and CCND2 could predict the therapeutic effect of sertraline, which may be associated with reducing suicidal ideation and improving cognitive function.

CONCLUSION

Our study may provide insights into the understanding of the underlying pathological mechanisms in adolescents with MDD.

Identification of Stable Reference miRNAs for miRNA Expression Analysis in Adult Neurogenesis Across Mouse and Human Tissues

Accurate normalization in miRNA studies requires the use of appropriate endogenous controls, which can vary significantly depending on cell types, treatments, and physiological or pathological conditions. This study aimed to identify suitable endogenous miRNA controls for neural progenitor cells (NPCs) and hippocampal tissues, both of which play crucial roles in neurogenesis. Using small RNA sequencing, we identified the most stable miRNAs in primary mouse NPCs and hippocampal tissues and accessed their stability using NormFinder analysis. Six miRNAs-miR-181d-5p, miR-93-5p, miR-103-3p, let-7d-5p, miR-26a-5p, and miR-125a-5p-demonstrated high stability and were evaluated for their suitability as endogenous controls across multiple experimental conditions. All selected miRNAs exhibited consistent expression in the NE-4C mouse cell line but not in ReNcells, a human cell line. For ReNcells, only miR-186-5p, one of the known reference miRNAs tested for comparison, showed stable expression. Notably, miR-103-3p and let-7d-5p were stably expressed in hippocampal tissues from both mouse and human samples but were absent in human brain pericytes, human brain microvascular endothelial cells, and SVG p12 cells, a human fetal glial cell line. This study is the first to identify optimal reference miRNAs for adult neurogenesis in both mouse and human samples, providing reliable options for miRNA normalization and improving the accuracy and reproducibility of miRNA expression analyses in neurogenesis research.

Post-stroke hippocampal neurogenesis is impaired by microvascular dysfunction and PI3K signaling in cerebral amyloid angiopathy

Ischemic stroke and cerebral amyloid angiopathy (CAA) pose significant challenges in an aging population, particularly in post-stroke recovery. Using the 5xFAD mouse model, we explore the relationship between CAA, ischemic stroke, and tissue recovery. We hypothesize that amyloid-beta accumulation worsens stroke outcomes by inducing blood-brain barrier (BBB) dysfunction, leading to impaired neurogenesis. Our findings show that CAA exacerbates stroke outcomes, with mice exhibiting constricted BBB microvessels, reduced cerebral blood flow, and impaired tissue recovery. Transcriptional analysis shows that endothelial cells and neural progenitor cells (NPCs) in the hippocampus exhibit differential gene expression in response to CAA and stroke, specifically targeting the phosphatidylinositol 3-kinase (PI3K) pathway. In vitro experiments with human NPCs validate these findings, showing that disruption of the CXCL12-PIK3C2A-CREB3L2 axis impairs neurogenesis. Notably, PI3K pathway activation restores neurogenesis, highlighting a potential therapeutic approach. These results suggest that CAA combined with stroke induces microvascular dysfunction and aberrant neurogenesis through this specific pathway.

EcoHIV Infection of Primary Murine Brain Cell Cultures to Model HIV Replication and Neuropathogenesis

BACKGROUND

EcoHIV is a chimeric HIV that replicates in mice in CD4+ T cells, macrophages, and microglia (but not in neurons), causing lasting neurocognitive impairment resembling neurocognitive disease in people living with HIV. The present study was designed to develop EcoHIV-susceptible primary mouse brain cultures to investigate the indirect effects of HIV infection on neuronal integrity.

RESULTS

We used two EcoHIV clones encoding EGFP and mouse bone marrow-derived macrophages (BMM), mixed mouse brain cells, or enriched mouse glial cells from two wild-type mouse strains to test EcoHIV replication efficiency, the identity of productively infected cells, and neuronal apoptosis and integrity. EcoHIV replicated efficiently in BMM. In mixed brain cell cultures, EcoHIV targeted microglia but did not cause neuronal apoptosis. Instead, the productive infection of the microglia activated them and impaired synaptophysin expression, dendritic density, and axonal structure in the neurons. EcoHIV replication in the microglia and neuronal structural changes during infection were prevented by culture with an antiretroviral.

CONCLUSIONS

In murine brain cell cultures, EcoHIV replication in the microglia is largely responsible for the aspects of neuronal dysfunction relevant to cognitive disease in infected mice and people living with HIV. These cultures provide a tool for further study of HIV neuropathogenesis and its control.

The S1 subunits of SARS-CoV-2 variants differentially trigger the IL-6 signaling pathway in human brain endothelial cells and downstream impact on microglia activation

Objectives

Cerebrovascular complications are prevalent in COVID-19 infection and post-COVID conditions; therefore, interactions of SARS-CoV-2 with cerebral microvascular cells became an emerging concern.

Methods

We examined the inflammatory responses of human brain microvascular endothelial cells (HBMEC), the main structural element of the blood-brain barrier (BBB), following exposure to the S1 subunit of the spike protein of different SARS-CoV-2 variants. Specifically, we used the S1 subunit derived from the D614 variant of SARS-CoV-2, which started widely circulating in March of 2020, and from the Delta variant, which started widely circulating in early 2021. We then further examined the impact of the HBMEC secretome, produced in response to the S1 exposure, on microglial proinflammatory responses.

Results

Treatment with S1 derived from the D614 variant and from the Delta variant resulted in differential alterations of the IL-6 signaling pathway. Moreover, the HBMEC secretome obtained after exposure to the S1 subunit of the D614 variant activated STAT3 in microglial cells, indicating that proinflammatory signals from endothelial cells can propagate to other cells of the neurovascular unit. Overall, these results indicate the potential for different SARS-CoV-2 variants to induce unique cellular signatures and warrant individualized treatment strategies. The findings from this study also bring further awareness to proinflammatory responses involving brain microvasculature in COVID-19 and demonstrate how the surrounding microglia react to each unique variant derived response.

Xiaoyaosan ameliorates CUMS-induced depressive-like and anorexia behaviors in mice via necroptosis related cellular senescence in hypothalamus

ETHNOPHARMACOLOGICAL RELEVANCE

Depression and anorexia often co-occur and share symptoms such as low mood, lack of energy, and weight loss. Xiaoyaosan is a classic formula comprising of a combination of eight herbs, possessing definitive therapeutic effects, minimal side effects, and economical benefits. It has been extensively employed in clinical treatment of ailments and symptoms such as depression, anxiety, and appetite problems. Nonetheless, its exact pharmacological mechanism with necroptosis remains incompletely explicit.

AIM OF THE STUDY

The aim of this study is to explore the potential mechanisms of anti-depressive and appetite-regulating effects of the active ingredients in Xiaoyaosan, and to investigate whether there is a correlation with necroptosis.

MATERIALS AND METHODS

The network pharmacology method was conducted to identify active ingredients, which were used to predict the possible targets of Xiaoyaosan and explore the potential targets in treating depression and anorexia by overlapping with differentially expressed genes (DEGs) screened from GEO datasets (GSE125441, GSE198597, and GSE69151). Afterwards, the protein-protein interaction (PPI) network, enrichment analyses, hub gene identification, co-expression study and molecular docking were used to study the potential mechanism of Xiaoyaosan. Then, a mice model of depression was established by chronic unpredictable mild stress (CUMS) and the incidence of necroptosis in the hypothalamus of CUMS mice was investigated, while verifying the key therapeutic target of Xiaoyaosan.

RESULTS

Through network pharmacology research, it had been discovered that the 145 active ingredients of the 8 herbs in the Xiaoyaosan could regulate 198 disease targets. Through PPI network analysis and functional enrichment analysis, it had been found that the pharmacological mechanism of Xiaoyaosan mainly involved biological processes such as oxidative stress, kinase activity, and DNA metabolism. It is related to various pathways such as cellular senescence, immune inflammation, and the cell cycle, and 9 hub targets had been identified. Further analysis of the 9 hub targets and the key PPI network clusters clarified the key mechanisms by which Xiaoyaosan exerts anti-depressant and appetite regulating effects, possibly related to necroptosis-mediated cellular senescence. Molecular docking of the key indicators of cellular senescence screened by bioinformatics, SIRT1, ABL1, and MYC, revealed that the key component regulating SIRT1 is 2-[3,4-dihydroxyphenyl]-5,7-dihydroxy-6-[3-methylbut-2-enyl]chromone in licorice root, Glabridin in licorice root regulates ABL1, and β-sitosterol found in Chinese angelica, debark peony root, and fresh ginger regulates MYC. Finally, through in vivo experiments, the expression of necroptosis in the hypothalamus of CUMS mice was verified. The regulatory effects of Xiaoyaosan on key substances RIPK1, RIPK3, MLKL, and p-MLKL were determined, while regulating effects on SIRT1, ABL1, and MYC were also observed.

CONCLUSION

The present study have revealed the common mechanism of Xiaoyaosan in treating depression and anorexia, indicating that the active ingredients of Xiaoyaosan may alleviate the symptoms of depression and anorexia by intervening in the pathways related to necroptosis and cellular senescence. The hub genes and common pathways identified by the study also provide new insights into the therapeutic targets of depression and anorexia, as well as the exploration of pharmacological mechanism of Xiaoyaosan.

Astrocytes: Role in pathogenesis and effect of commonly misused drugs in the HIV infected brain

The roles of astrocytes as reservoirs and producers of a subset of viral proteins in the HIV infected brain have been studied extensively as a key to understanding HIV-associated neurocognitive disorders (HAND). However, their comprehensive role in the context of intersecting substance use and neurocircuitry of the reward pathway and HAND has yet to be fully explained. Use of methamphetamines, cocaine, or opioids in the context of HIV infection have been shown to lead to a faster progression of HAND. Glutamatergic, dopaminergic, and GABAergic systems are implicated in the development of HAND-induced cognitive impairments. A thorough review of scientific literature exploring the variety of mechanisms in which these drugs exert their effects on the HIV brain and astrocytes has revealed marked areas of convergence in overexcitation leading to increased drug-seeking behavior, inflammation, apoptosis, and irreversible neurotoxicity. The present review investigates astrocytes, the neural pathways, and mechanisms of drug disruption that ultimately play a larger holistic role in terms of HIV progression and drug use. There are opportunities for future research, therapeutic intervention, and preventive strategies to diminish HAND in the subset population of patients with HIV and substance use disorder.

Synergistic Impairment of the Neurovascular Unit by HIV-1 Infection and Methamphetamine Use: Implications for HIV-1-Associated Neurocognitive Disorders

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.