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Despite the growing interest in cell- and exosome-based therapies for neurological diseases including Alzheimer's disease (AD), there is still a gap in the investigation of more effective treatments in terms of efficacy, safety, and durability of effect. This study aimed to compare the therapeutic potential of astrocyte cells and their derived exosomes (AS-Exos) in restoring cognitive function in a mouse model of AD. AD model was induced by bilateral electrical lesioning of the nucleus basalis of Meynert (NBM). Astrocytes were isolated from neonatal rat brains, and AS-Exos were harvested from astrocyte-conditioned media using an AnaCell extraction kit. Seven days after lesion induction, astrocytes and AS-Exos were stereotaxically injected into the NBM. Four weeks later, behavioral assessments (passive avoidance and locomotor activity), electrophysiological recordings (EEG), and biochemical measurements of hippocampal brain-derived neurotrophic factor (BDNF) and acetylcholine (ACh) levels were performed. AS-Exos were confirmed as cup-shaped vesicles (30-150 nm) expressing the exosomal surface markers CD9, CD63, and CD81. NBM lesions significantly reduced step-through latency (STL), hippocampal BDNF and ACh levels, and disrupted EEG oscillatory patterns. Treatment with AS-Exos markedly improved STL and produced greater increases in hippocampal BDNF and ACh levels compared with AD and AD+saline groups. EEG analysis also revealed enhanced beta, alpha, and gamma power, with the most robust normalization observed in the AS-Exos group. AS-Exos demonstrated superior biochemical and electrophysiological benefits compared with astrocyte transplantation and provided equal or greater improvement in behavioral outcomes. These findings highlight AS-Exos as a promising cell-free therapeutic strategy for alleviating cognitive deficits associated with AD. Show less

Microglial decline in the dentate gyrus is an important mechanism in the development of depression-like behaviors in stressed animals. Reversing this decline with low-dose lipopolysaccharide (LPS) can produce rapid antidepressant effects, yet the underlying mechanisms remain incompletely understood. Our previous work identified a critical role for astrocytic P2Y1 receptor (P2Y1R) activation and subsequent dentate gyrus extracellular signal-regulated kinase 1/2 (ERK1/2)-brain-derived neurotrophic factor (BDNF) signaling in the antidepressant effect of low-dose LPS. This study elucidates the signaling cascade linking astrocytic P2Y1R mobilization to the antidepressant effect of low-dose LPS. We found that low-dose LPS promoted glutamate release through ATP-triggered astrocytic P2Y1R signaling. Blockade of N-methyl-D-aspartic acid (NMDA) receptors, but not metabotropic receptors, and the GluN2B subtype of NMDA receptors abolished the antidepressant effect of low-dose LPS. GluN2B knockdown also abolished the reversal effect of low-dose LPS on CUS-induced depression-like behaviors and impairment of dentate gyrus ERK1/2-BDNF signaling. Moreover, chelating intracellular Ca Show less

Parkinson's disease (PD) is a common neurodegenerative disorder involving multiple pathological processes. Bergapten (BeG) exhibits various pharmacological activities, including anti-inflammatory, antioxidant and neuroprotective effects, but its mechanism of action in PD remains unclear. This study aimed to investigate the neuroprotective effects and underlying mechanisms of BeG in PD models. An in vitro neuroinflammation model was established using LPS-treated astrocytes. In-vitro studies demonstrated that BeG counteracted LPS-induced astrocyte activation by reducing the expressions of GFAP, inflammatory mediators (IL-6, TNF-α, IL-1β), and A1 polarization markers. It alleviated ERS (as indicated by reduced levels of GRP78, CHOP) and apoptosis (as shown by changes in Bax, caspase-3) while enhancing Bcl-2. Mechanistically, BeG suppressed LCN2 expression and JAK2/STAT3 phosphorylation, with LCN2 overexpression attenuating its protective effects. In MPTP-treated mice, BeG improved motor function, preserved dopaminergic neurons, and reduced astrocyte activation and A1 polarization. It increased neurotrophic factors (BDNF, GDNF) while decreasing inflammation, ER stress and apoptotic markers. The inhibition of the LCN2/JAK2/STAT3 pathway was consistently observed in both models, suggesting its central role in BeG's neuroprotective mechanism. These findings suggest that BeG exerts neuroprotective effects in PD by inhibiting the LCN2/JAK2/STAT3 signaling pathway, thereby effectively inhibiting astrocyte activation-mediated neuroinflammation and ERS. Show less

The high global prevalence of anxiety disorders, coupled with the limitations of existing treatments, constitutes a severe public health challenge. Chronic stress, as a core environmental trigger, has garnered increasing attention for its mechanism of mediating brain-derived neurotrophic factor (BDNF) imbalance through neuroinflammation. BDNF dysregulation may contribute to anxiety disorders, particularly in subtypes with heightened neuroinflammation. The objective of this review is to comprehensively and methodically explores the potential role of the "M1-like microglia-A1-like astrocyte axis (M1-A1 axis)" in linking chronic stress to BDNF dysregulation in anxiety disorders, and to provide a theoretical basis for intervention strategies targeting this axis. By synthesizing recent relevant clinical and preclinical evidence, this review integrates evidence from molecular to systems levels, focusing on the activation mechanisms of neuroinflammation under chronic stress, the crosstalk between glial cells, and their regulatory network on BDNF. Chronic stress is associated with peripheral and central cascades through hypothalamic-pituitary-adrenal (HPA) axis activation and gut microbiota disruption. Within the central nervous system (CNS), stress induces microglial polarization toward the pro-inflammatory microglial subpopulations (hereinafter referred to as M1-like microglia). The signals released by M1-like microglia, such as Interleukin-1 alpha (IL-1α), Tumor Necrosis Factor-alpha (TNF-α), and Complement Component 1q (C1q) (ITC), drive astrocytes to transform into the neurotoxic astrocyte states (hereinafter referred to as A1-like astrocyte), forming the "M1-A1 axis". This axis contributes to BDNF dysregulation through the following mechanisms: (1) Release of pro-inflammatory cytokines inhibits BDNF transcription and translation; (2) Induction of astrocytic lactate metabolism disruption, which impairs neuronal energy supply and acidifies the microenvironment, further amplifying inflammation and affecting BDNF expression; (3) Compromise of the blood-brain barrier(BBB)enables peripheral immune cells to penetrate into the CNS, and these cells work in synergy with central glial cells to amplify inflammation. The reduction in BDNF and the imbalance in the ratio of its precursor to mature form ultimately lead to impaired synaptic plasticity in brain regions like the hippocampus (HIP) and amygdala, precipitating anxiety-like behaviors. Existing pharmacological interventions are inadequate to reverse this pathological process. The M1-A1 axis may serve as a key node linking chronic stress to BDNF dysregulation and anxiety disorders. Targeting the phenotypic transformation of glial cells, repairing the BBB, or modulating glial cell metabolism (e.g., lactate shuttle) may represent potential strategies requiring further validation. Future research should focus on the spatiotemporal dynamics of this axis and its clinical translation. Show less