Search Results (112)

Animal studies have shown that early life exposure to general anesthetics may impair brain development. However, the implications of this phenomenon in human patients remain unclear. In this study, we use an induced pluripotent stem cell (iPSC)-derived human brain microphysiological system (bMPS) to investigate the effects of early sevoflurane (SEV) exposure on human brain development. Human iPSCs were cultured and differentiated into neural progenitor cells (NPCs) and then into bMPS. At week 8, bMPSs were exposed to 2.4% SEV for 4 h. Four weeks after exposure, immunofluorescence (IF), Western blotting (WB), and quantitative real-time polymerase chain reaction (qPCR) were conducted to evaluate the alteration of nerve cells in bMPS. After SEV exposure, the number of apoptotic cells increases, and the level of neural differentiation markers decreases. The ratios of mature neurons over NPCs and mature oligodendrocytes over oligodendrocyte progenitor cells (OPCs) are reduced, which leads to a reduction in myelination. SEV also impedes the development of astrocytes and synaptogenesis, especially the formation of excitatory synapses. Meanwhile, SEV increases the expression of molecules in the mammalian target of rapamycin (mTOR) signal pathway. In conclusion, early SEV exposure substantially disrupts the development of human brain tissue, and the mTOR signal pathway is likely to be involved in this alteration. Full article

Traumatic brain injury (TBI) initiates a cascade of molecular and cellular reactions leading to long-term disturbances of neuronal and glial homeostasis. One of the key mechanisms of secondary injury is a pathological increase in intracellular Ca²⁺ concentration. Parvalbumin (PV) plays an important role in the regulation of Ca²⁺ homeostasis in neurons. In turn, connexin 43 (Cx43) is the principal protein of astrocytic gap junctions (GJs), which ensure neuroglial communication. The spatiotemporal changes in these proteins and the mechanisms of their interaction after TBI remain insufficiently studied. In the present study, a comprehensive analysis of the expression, localization, and spatial organization of PV and Cx43 in the cerebral cortex following TBI was performed. In intact tissue, PV was localized predominantly in neurons, whereas Cx43 formed typical punctate structures of astrocytic GJs. Twenty-four hours after TBI, a sharp activation of PV with pronounced nuclear translocation was observed against the background of a catastrophic decrease in Cx43 expression, accompanied by a reduction in the number of NeuN⁺ neurons and signs of apoptosis. However, after 7 days, a mirror-opposite effect was detected, characterized by decreased PV expression and increased Cx43 levels with its aggregation into cluster-like structures, as well as partial restoration of NeuN immunoreactivity. In addition, molecular dynamics simulations demonstrated that the stability of the PV–Cx43 complex is determined by the presence of Ca²⁺ and physiological pH, whereas acidosis and Ca²⁺ overload destabilize their interaction. Taken together, these results reveal a phase-dependent mirror-opposite pattern of PV and Cx43 expression and localization and emphasize the key role of Ca²⁺- and pH-dependent neuroglial interactions in TBI. Full article

Advantageous functions have been attributed to amyloid β, which helps explain its expression despite a propensity to aggregate. Besides supporting cognitive processes, it has antimicrobial activity, e.g., amyloid β can entrap pathogens or disrupt their membranes. Since iron is an essential element for invading organisms, limiting its availability is an antimicrobial strategy. This can be achieved by various means, such as reducing circulating iron, as is the case for anemia of inflammation or anemia of chronic disease, which may occur in Alzheimer’s disease. The protein lactoferrin both sequesters iron and generates proteolytic fragments with antimicrobial properties, and amyloid β may have similar traits. Amyloid β, which is derived from proteolytic cleavage of amyloid precursor protein, directly inhibits microorganisms. In addition, it binds redox-active metals, such as iron and copper. After being generated, amyloid β can enter the interstitial fluid and undergo clearance by a variety of mechanisms (e.g., glymphatic system, transport across the blood–brain barrier, and uptake by microglia or astrocytes). This clearance, together with its small size and iron-binding properties, positions amyloid β to perform a surveillance function to access, capture, and export labile iron. By removing extraneous iron, amyloid β also helps to limit metal-catalyzed reactions that cause tissue damage. In summary, besides preventing the aggregation and neurotoxicity of amyloid β, the clearance of amyloid β from the CNS may serve a surveillance function to remove loosely bound iron to avert injury by redox reactions and enable amyloid β to function as a mammalian siderophore making iron unavailable to invading microorganisms. Full article

Background/Objectives: Maresin-1 (MaR1), a specialized pro-resolving mediator (SPM) derived from omega-3 fatty acids, has demonstrated potent anti-inflammatory and pro-resolving properties. However, its effects on depression-like behaviors and the associated dynamics of neuroinflammation, particularly in the context of chronic stress, are not yet fully understood. This study aimed to investigate the therapeutic potential of MaR1 in a chronic unpredictable stress (CUS) model and to monitor its dynamic effects on neuroimmune activity using longitudinal in vivo imaging. Methods: Adolescent male C57BL/6J mice were subjected to a 5-week CUS protocol. Mice exhibiting stable anhedonia were randomized to receive intraperitoneal injections of either MaR1 (5 µg/kg) or vehicle every other day for 4 weeks. During this period, CUS procedures were maintained. Depression-like behaviors were assessed using the sucrose preference test (SPT), tail suspension test (TST), and open field test (OFT). Dynamic changes in neuroinflammation were monitored via longitudinal [18F]DPA-714 positron emission tomography (PET) scans at baseline and after 2 and 4 weeks of treatment. Ex vivo analyses included immunofluorescence quantification of hippocampal microglia (ionized calcium-binding adaptor molecule 1, Iba1), astrocytes (glial fibrillary acidic protein, GFAP), and 18 kDa translocator protein (TSPO) co-expression, alongside quantitative polymerase chain reaction (qPCR) and Western blotting for inflammatory markers (IL-1β, IL-4, TSPO). Results: MaR1 treatment selectively alleviated depression-like behaviors, significantly reversing CUS-induced anhedonia in the SPT and improving locomotor activity, while its effect on despair-like behavior (TST) was not statistically significant. Longitudinal PET imaging revealed a biphasic neuroimmune response, characterized by an initial increase in [18F]DPA-714 standardized uptake value (SUV) at 2 weeks, followed by a return toward baseline at 4 weeks. Histologically, MaR1 reversed CUS-induced hippocampal microglial loss, resulting in a rebound of microglial numbers, and normalized astrocytic activation. At the molecular level, MaR1 dynamically modulated cytokine expression, culminating in a significant upregulation of the pro-resolving marker IL-4 and TSPO at 4 weeks. Conclusions: These findings indicate that Maresin-1 treatment is associated with behavioral improvement and dynamic modulation of glial activity and TSPO PET signals in the hippocampus. This study highlights the value of TSPO PET imaging for monitoring dynamic glial changes during therapeutic intervention and provides supportive evidence for targeting neuroimmune pathways in depression. Full article

Glycosaminoglycans (GAGs), also named ‘mucopolysaccharides’, are nodal constituents of the connective tissue matrix which go through synthesis, demolition, and reconstruction within several cellular structures: an abnormal GAG catabolism is the basis of progressive intra-lysosomal accumulation of non-metabolized GAGs, defining all mucopolysaccharidoses (MPS), protean disorders characterized by physical abnormalities and multi-organ failure depending on the specific site of non-renewable GAGs stored. A severe cognitive decline is typically observed in the Sanfilippo syndrome, which corresponds to MPS type III, a group of four inherited neurodegenerative diseases resulting from the lack of specific enzymes involved in heparan sulfate (HS) metabolism. As a consequence, the storage of partially degraded HS fragments within lysosomes of the central nervous system elicits chain inflammatory reactions involving the NLRP3-inflammasome in microglia and astrocytes, which cease their homeostatic and immune functions and finally compromise neuron survival. This article provides an overview of the neuroinflammatory picture observed in children with MPS type III, postulating a role of HS accumulation to prime innate immunity responses which culminate with pro-inflammatory cytokine release in the brain and highlighting the relevance of interleukin-1 as a main contributor to neuroinflammation. Full article

Neuropeptides (NPs) are small molecular messengers synthesized in large dense core vesicles (LDCVs) and secreted to the extracellular space. In the central nervous system (CNS), NPs are secreted to the synaptic space, playing crucial roles in modulating neurons, astrocytes, microglia, oligodendrocytes, and other glial cells, through G-protein-coupled receptors, thereby influencing complex multicellular responses. During neuroinflammation, NPs regulate glial and neuronal reactions to inflammatory signals, promoting resolution and preventing chronic, non-resolving inflammation. For example, NPs inhibit apoptosis in neurons and oligodendrocytes while inducing anti-inflammatory effects in microglia and astrocytes, modulating cytokine secretion. Here, we present the notion that neuropeptides could participate in neuroinflammatory progression, altering glial responses, leading to excessive, non-resolutive inflammation when dysregulated. NP signaling—whether excessive or deficient—can disrupt specific cellular processes, leading to pathological inflammation, gliosis, and functional loss—hallmarks of neurodegenerative diseases. Despite their significance, the precise mechanisms underlying NP-mediated effects remain incompletely understood. This review synthesizes experimental and translational evidence highlighting the pivotal role of NPs in resolving neuroinflammation and explores how targeting NPs or their receptors could offer novel therapeutic strategies for neurodegenerative disorders. Further research is needed to elucidate the specific signaling pathways and receptor dynamics involved, which could pave the way for innovative treatments that address the root causes of these debilitating conditions. Full article

Astrocytic tumors are a heterogeneous group of glial neoplasms characterized by marked differences in biological behavior and patient prognosis. Transforming growth factor-beta (TGF-β) signaling plays a pivotal role in astrocytoma pathogenesis; however, the extent and mechanisms of its epigenetic regulation remain poorly understood. This study aimed to investigate how promoter methylation and microRNA-mediated mechanisms regulate key genes within the TGF-β signaling pathway across various astrocytoma grades. Tumor tissue samples from 65 patients with WHO grade II–IV astrocytomas were analyzed using Affymetrix gene expression and microRNA microarrays. Promoter methylation of TGF-β signaling genes was assessed using methylation-specific polymerase chain reaction (MSP). Gene expression was validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR), and protein levels were quantified using enzyme-linked immunosorbent assay (ELISA). MicroRNA targets were predicted using bioinformatic tools, and survival analyses were conducted using Kaplan–Meier and Cox regression models. Six genes—SMAD1, SMAD3, SKIL, BMP2, SMAD4, and MAPK1—showed significant upregulation in high-grade tumors (fold change > 5.0, p < 0.05), supported by RT-qPCR and protein-level data. Promoter hypomethylation and reduced expression of regulatory microRNAs (e.g., hsa-miR-145-5p targeting SMAD3) were more common in higher-grade tumors. Protein–protein interaction analysis indicated strong functional interconnectivity among the overexpressed genes. High protein levels of SMAD1, SMAD3, and SKIL were significantly associated with shorter overall survival (p < 0.001). This multi-level analysis reveals that astrocytic tumor progression involves epigenetic derepression and microRNA-mediated dysregulation of TGF-β signaling. Elevated expression of SMAD1, SMAD3, and SKIL emerged as strong prognostic indicators, underscoring their potential as biomarkers and therapeutic targets in astrocytic tumors. Full article

Background: Severe damage to one side of the brain often leads to adverse consequences and can also cause widespread changes throughout the brain, especially in the contralateral area. Studying molecular changes in the contralateral cerebral hemisphere, especially with regard to genetic regulation, can help discover potential treatment strategies to promote recovery after severe brain trauma on one side. Methods: In our study, the right motor cortex was surgically removed to simulate severe unilateral brain injury, and changes in glial cells and synaptic structure in the contralateral cortex were subsequently assessed through immunohistological, morphological, and Western blot analyses. We conducted transcriptomic studies to explore changes in gene expression levels associated with the inflammatory response. Results: Seven days after corticotomy, levels of reactive astrocytes and hypertrophic microglia increased significantly in the experimental group, while synapsin-1 and PSD-95 levels in the contralateral motor cortex increased. These molecular changes are associated with structural changes, including destruction of dendritic structures and the encapsulation of astrocytes by synapses. Genome-wide transcriptome analysis showed a significant increase in gene pathways involved in inflammatory responses, synaptic activity, and nerve fiber regeneration in the contralateral cortex after corticorectomy. Key transcription factors such as NF-κB1, Rela, STAT3 and Jun were identified as potential regulators of these contralateral changes. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) confirmed that the mRNA expression levels of Cacna1c, Tgfb1 and Slc2a1 genes related to STAT3, JUN, and NF-κB regulation significantly increased in the contralateral cortex of the experimental group. Conclusions: After unilateral brain damage occurs, changes in the contralateral cerebral hemisphere are closely related to processes involving inflammation and synaptic function. Full article

The habenula (Hb) of the epithalamus is formed of the medial (MHb) and lateral (LHb) parts. The improper functioning of the Hb may lead to depression and anxiety. The glutamate excitotoxicity is accompanied by astroglia reactivity and leads to the damage of nervous system structures. The aim of the study was to assess the influence of monosodium glutamate (MSG) administrated subcutaneously to rats in doses of 2 g/kg b.w. (I) and 4 g/kg b.w. (II), on astroglia in the MHb and LHb. Based on immunohistochemical reactions, the morphology, number of astrocytes immunoreactive for glial fibrillary acidic protein (GFAP-IR) and S100β protein (S100β-IR), and their surface area, perimeter, number and length of processes, and cytoplasmic-nuclear immunostaining intensity for the studied proteins were assessed. In the MHb of animals receiving MSG, especially at a high dose, hypertrophy and an increase in the number of GFAP-IR and S100β-IR cells were demonstrated. In the LHb, only hypertrophy of processes in S100β-positive glia was observed. The immunostaining intensity increased in GFAP-IR glia and decreased in S100β-IR cells only in animals from group I. The results revealed that astroglia respond to MSG depending on its dose and the Hb part. This different behavior of glia may indicate their different sensitivity and resistance to damaging factors. Full article

Amyotrophic lateral sclerosis (ALS) remains a progressive neurodegenerative disease, lacking effective causal therapies. The Wobbler mouse model harboring a spontaneous autosomal recessive mutation in the vacuolar protein sorting associated protein (Vps54), has emerged as a valuable model for investigating ALS pathophysiology and potential treatments. This model exhibits cellular and phenotypic parallels to human ALS, including protein aggregation, microglia and astrocyte activation, as well as characteristic disease progression at distinct stages. Exploring the underlying pathomechanisms and identifying therapeutic targets requires a comprehensive analysis of gene and protein expression. In this study, we examined the expression of three well-established housekeeping genes and proteins—calnexin, ß-actin, and ßIII-tubulin—in the cervical spinal cord of the Wobbler model. These candidates were selected based on their demonstrated stability across various systems like animal models or cell culture. Calnexin, an integral protein of the endoplasmic reticulum, ß-actin, a structural component of the cytoskeleton, and ß-tubulin III, a component of microtubules, were quantitatively assessed using quantitative reverse transcription-polymerase chain reaction (RT-PCR) for gene expression and Western blotting for protein expression. Our results revealed no significant differences in the expression of CANX, ACTB, and TUBB3 between spinal cords of wild-type and Wobbler mice at the symptomatic stage (p40) at both the gene and protein levels. These findings suggest that the pathophysiological alterations induced by the Wobbler mutation do not significantly affect the expression of these crucial housekeeping genes and proteins at p40. Overall, this study provides a basis for further investigations using the Wobbler mouse model, while highlighting the potential use of calnexin, ß-actin, and ßIII-tubulin as reliable reference genes and proteins in future research to aid in the discovery for effective therapeutic interventions. Full article

Alzheimer’s disease (AD) is a neurodegenerative condition in which amyloid-beta (Aβ) plaques trigger oxidative stress (OS) and neuroinflammation, causing memory loss. OS and neurodegeneration can also be caused by reactive astrocytes, thereby promoting AD via toxic metabolite accumulation in the astrocytic urea cycle. However, the effect of molecular hydrogen (H₂) on this cycle remains unknown. Therefore, we investigated whether H₂ treatment could reduce OS-induced neurodegeneration and memory loss. 5xFAD (n = 14) and wild-type (n = 15) mice were randomized into four groups and treated with either 3% hydrogen gas (H₂) or vehicle for 60 days. Cognitive behaviors were evaluated using the Morris water maze and Y-maze tests. In addition, we used biochemical assays to measure ammonia and hydrogen peroxide (H₂O₂) levels in the hippocampi of the mice and AβO-treated primary mouse astrocytes. Aβ, γ-aminobutyric acid (GABA), and the expression of inflammatory markers were evaluated using immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (qRT-PCR). We observed that H₂ treatment significantly prevented cognitive deficits, oxidative stress, the accumulation of toxic metabolites, and the increase in inflammatory markers in 5xFAD mice. These results suggest that H₂ therapy can mitigate toxic metabolites in the astrocytic urea cycle, thereby reducing neurodegeneration and memory loss in AD. Full article

Chronic inflammation is increasingly recognized as a driver of glioma progression, with tumor necrosis factor-alpha (TNF-α) playing a central role in modulating the tumor microenvironment. This study aimed to investigate the expression profiles and regulatory mechanisms of TNF-α and its downstream mediators—including interleukin-1 beta (IL-1β), Mitogen-Activated Protein Kinase Kinase Kinase 8 (MAP3K8), and Mitogen-activated protein kinase kinase 7 (MAP2K7)—in astrocytic tumors of varying malignancy. We conducted an integrative molecular analysis of 60 human astrocytic tumor samples (20 G2, 12 G3, 28 G4) using transcriptomic microarrays, Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR), Enzyme-Linked Immunosorbent Assay (ELISA), Western blotting, immunohistochemistry, methylation-specific PCR, and miRNA profiling. Prognostic associations were evaluated using Kaplan–Meier survival and Cox regression analyses. TNF-α, IL-1β, and MAP3K8 were significantly upregulated in high-grade tumors, with log₂ fold changes ranging from 5.56 to 8.76 (p < 0.001). High expression of TNF-α (HR = 2.10, 95% CI: 1.27–3.46, p = 0.004), IL-1β (HR = 2.35, 95% CI: 1.45–3.82, p = 0.001), and MAP3K8 (Hazard Ratio; HR = 1.88, 95% confidence interval; 95% CI: 1.12–3.16, p = 0.015) was associated with poorer overall survival. miR-34a-3p and miR-30 family members, predicted to target TNF-α and IL-1β, were markedly downregulated in G3/G4 tumors (e.g., miR-30e-3p fold change: –3.78, p < 0.01). Promoter hypomethylation was observed in G3/G4 tumors, supporting epigenetic activation. Our findings establish a multi-layered regulatory mechanism of TNF-α signaling in astrocytic tumors. These data highlight the TNF-α/IL-1β/MAP3K8 axis as a critical driver of glioma aggressiveness and a potential therapeutic target. Full article

In previous studies, we isolated a series of novel gentisides with nerve growth factor (NGF)-mimic activities from Gentiana rigescens Franch and conducted continuous structure–activity relationship (SAR) studies. Recently, a lead compound named TBG096 was discovered with significant NGF-mimic activity, low toxicity, and ability to pass through the blood–brain barrier (BBB). At the cell level, TBG096 exerts NGF-mimic activity by regulation of heat-shock cognate protein 70 (Hsc70) and downstream proteins. Subsequently, high-fat diet (HFD)-induced Alzheimer disease (AD) mouse models were used to evaluate the anti-AD efficacy of the compound. TBG096 significantly improved the memory dysfunction of AD mice at doses of 0.1, 5, and 20 mg/kg, respectively. In order to elucidate the mechanism of action of the compound against AD, the RNA-sequence analysis of transcriptomics, quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence staining, and Western blot analysis were performed using animal samples. TBG096 significantly increased the expression of the Wnt gene family (Wnt10b, Wnt5a, and Wnt1) and the number of mature neurons and newborn neurons in the hippocampus and cerebral cortex of AD mice, respectively. At the same time, it reduced the activity of microglia, astrocyte cells, and expression of inducible nitric oxide synthase (INOS) in the brain. Moreover, this compound significantly increased phosphorylated-adenosine 5′-monophosphate-activated protein kinase (AMPK), Hsc70, and lysosomal-associated membrane protein 2a (LAMP2A) and decreased the expression of hexokinase 2 (HK2), pyruvate kinase M2 (PKM2), amyloid precursor protein (APP), microtubule-associated protein tau (Tau), phosphoryl-Tau, and β-amyloid (Aβ) at the protein level. These results suggest that TBG096 produced the NGF-mimic activity and the anti-AD effect via promoting neurogenesis and modification of the Hsc70/HK2/PKM2/LAMP2A signaling pathway, proposing a potential novel approach to counteracting cognitive decline by developing small molecules that promote neurogenesis and the Hsc70 signaling pathway. Full article

Background/Objectives: Parkinson’s disease (PD) is a neuro-degenerative disease for which a radical cure is not available, only symptomatic control. Studies have shown that hypoxia may have disease-modifying effects on PD. Methods: Herein, we investigated whether short-term hypoxia activates astrocytes and whether it has a protective effect on pre-formed fibril (PFF)-treated primary cortical neurons. Results: Long-term hypoxia suppresses astrocyte activation and induces cell death, whereas short-term hypoxia activates astrocytes without affecting cellular apoptosis or viability. Short-term hypoxia restored the cellular apoptosis and viability of PFF-treated neurons and reduced toxic phospho-α-synuclein (p-α-syn) aggregation. Similarly, the short-term hypoxia-exposed astrocyte-conditioned medium rescued cellular apoptosis and the viability of PFF-treated neurons and p-α-syn expression. Quantitative polymerase chain reaction revealed that short-term hypoxia promotes protective A2 astrocytes and suppresses toxic A1 astrocytes. Conclusions: Our findings suggest that short-term hypoxia has a neuro-protective effect against PD by activating protective A2 astrocytes, which rescue PFF-induced neuronal cell death. This provides insights into the clinical implications of short-term hypoxia as a disease-modifying PD strategy. Full article

Methamphetamine (METH) use is frequent among people with HIV (PWH) and appears to increase the risk of neuronal injury and neurocognitive impairment (NCI). This study explored in vivo the effects of a 12 week (long-term), low-dose METH regimen in a transgenic animal model of neuroHIV with inducible expression of HIV-1 transactivator of transcription (Tat). Seven months after transient Tat induction and five months after METH exposure ended, we detected behavioral changes in the Barnes maze (BM) spatial memory task in the Tat and METH groups but not the combined Tat + METH group. The novel object recognition (NOR) task revealed that Tat extinguished discrimination in female animals with and without METH, although METH alone slightly improved NOR. In contrast, in males, Tat, METH, and Tat + METH all compromised NOR. Neuropathological examination detected sex-dependent and brain region-specific changes of pre-synaptic terminals, neurites, and activation of astrocytes and microglia. RNA-sequencing and quantitative reverse transcription polymerase chain reaction indicated that METH and Tat significantly altered gene expression, including factors linked to Alzheimer’s disease-like NCI. In summary, chronic low-dose METH exerts long-term effects on behavioral function, neuropathology, and mRNA expression, and modulates the effects of Tat, suggesting sex-dependent and -independent mechanisms may converge in HIV brain injury and NCI. Full article