Inflammatory Response in the CNS: Friend or Foe?

Environmental exposures and familial background alter the induction of neuropathology and inflammation after SARS-CoV-2 infection

Post-infection sequela of several viruses have been linked with Parkinson's disease (PD). Here, we investigated whether mice infected with SARS-CoV-2 alone or in combination with two putative Parkinsonian toxins, MPTP and paraquat, increased the susceptibility to develop Parkinsonian pathology. We also examined if G2019S LRRK2 mice had any change in sensitivity to SARS-CoV-2 as well as if vaccination against this virus altered any neuropathology. Infection with WA-1/2020 or Omicron B1.1.529 strains sensitized both WT and G2019S LRRK2 mice to the neuropathological effects of a subtoxic exposure to MPTP, but not paraquat. These neuropathologies were rescued in WT mice vaccinated with mRNA- or protein-based SARS-CoV-2 vaccines. However, G2019S LRRK2 mutant mice were only protected with the protein-based vaccine. These results highlight the role of both environmental exposures and familial background on the development of Parkinsonian pathology secondary to viral infection and the benefit of vaccines in reducing these risks.

The basolateral amygdala and striatum propagate alpha-synuclein pathology causing increased fear response in a Parkinson's disease model

Alpha-synuclein (aSyn)-related pathology crucially contributes to the pathogenesis of Parkinson's disease, a frequent and incurable neurodegenerative disease characterized by progressive motor and non-motor symptoms. Anxiety and fear- related neuropsychiatric symptoms develop frequently and early in the disease, but a lack of understanding of pathogenesis hampers rational therapy. This study aimed to decipher whether aSyn pathology in the basolateral amygdala (BLA) is causative of fear and anxiety. Bilateral stereotaxic injections of human aSyn-preformed amyloid fibrils (PFF) in BLA, striatum, or substantia nigra were conducted in female mice overexpressing human aSyn (Thy1-aSyn) and in wildtype littermates (WT). We characterized the propagation of aSyn pathology and related neuropathological changes across brain regions and examined the behavioral and fear responses in mice up to 2 months post-injection of PFF. While PFF injections induced local aSyn fibril pathology close to all respective injection sites in transgenic mice, we observed differences in propagation, downstream pathology and behavioral alterations. The BLA and the striatum, but not the substantia nigra, effectively propagated aSyn pathology to connected brain regions at 2.5 months post injection. This involved enhanced microgliosis and astrogliosis in the nigrostriatal system and loss of GABAergic parvalbuminergic interneurons in the striatum and corticolimbic brain regions. Intra-BLA PFF injections resulted in increased cued fear response in both transgenic mice and WT mice at 1 month post injection. The effect was more pronounced in the transgenic mice. Conversely, intra-striatal PFF injections enhanced contextual fear in WT at 2 months post injection. These findings imply that increased fear is inducible by aSyn pathology, especially if originating in the BLA or striatum. Furthermore, both regions are hub regions of aSyn pathology propagation, thereby contributing to disease progression. These insights provide mechanisms that can guide rational therapeutic development.

Targeted miRNA Delivery in Epilepsy: Mechanisms, Advances, and Therapeutic Potential

Epilepsy, a neurological disorder characterized by recurrent seizures, presents significant therapeutic challenges, with roughly 30% of individuals demonstrating resistance to antiepileptic drugs. Drug-resistant epilepsy diminishes patients' quality of life and underscores the critical need for innovative therapeutic approaches. MicroRNAs, small non-coding RNA molecules, have emerged as key regulators in the pathogenesis of epilepsy, influencing neuronal excitability, synaptic plasticity, and neuroinflammatory processes. By targeting multiple genes and pathways involved in epileptogenesis, miRNAs offer promising opportunities for precision medicine. This review explores the dual roles of specific miRNAs in epilepsy, acting as both promoters and inhibitors of pathogenic pathways, and highlights recent advancements in miRNA-based therapeutic delivery systems. State-of-the-art approaches, including lipid nanoparticles, viral vectors, and exosome-based systems, are being developed to address challenges such as blood-brain barrier penetration, targeted delivery, and minimizing systemic side effects. These advancements lay the groundwork for more effective and personalized treatment strategies.

Microglia Sing the Prelude of Neuroinflammation-Associated Depression

Major depressive disorder (MDD) is a psychiatric condition characterized by sadness and anhedonia and is closely linked to chronic low-grade neuroinflammation, which is primarily induced by microglia. Nonetheless, the mechanisms by which microglia elicit depressive symptoms remain uncertain. This review focuses on the mechanism linking microglia and depression encompassing the breakdown of the blood-brain barrier, the hypothalamic-pituitary-adrenal axis, the gut-brain axis, the vagus and sympathetic nervous systems, and the susceptibility influenced by epigenetic modifications on microglia. These pathways may lead to the alterations of microglia in cytokine levels, as well as increased oxidative stress. Simultaneously, many antidepressant treatments can alter the immune phenotype of microglia, while anti-inflammatory treatments can also have antidepressant effects. This framework linking microglia, neuroinflammation, and depression could serve as a reference for targeting microglia to treat depression.

Impact of Psychological Stress and Spontaneous Tumour Regression on the Hippocampal Proteome in a Mouse Model of Breast Cancer

Cognitive impairment is common in people diagnosed with breast cancer, but the molecular mechanisms that underlie maladaptive changes in the brain are unknown. The psychological stress of a cancer diagnosis is certainly a contributing factor. Here, we investigated alterations in the hippocampal proteome in response to both cancer and psychological stress using label-free quantitative mass spectrometry techniques. An orthotopic syngeneic model of triple-negative breast cancer (TNBC) was established by injecting Py230 cells into the mammary fat pads of female C57Bl/6 mice. Half of the mice were subjected to a daily restraint stress paradigm. Mice that experienced both cancer and restraint stress lost weight and displayed larger tumours compared to non-stressed mice. Their urinary corticosterone levels were also elevated, as measured by enzyme-linked immunosorbent assay. Non-stressed tumour-bearing mice displayed higher levels of TNFα in the prefrontal cortex (PFC) compared to stressed mice with cancer. Flow cytometry results suggested that the CD4+/CD8+ T cell ratios were also raised in non-stressed tumour-bearing mice compared to both controls and stressed mice with TNBC. Bioinformatic analysis of hippocampal proteomes indicated that cancer alone causes reduced mitochondrial respiration and ATP synthesis, as well as impaired glutamate recycling and synaptic plasticity. Moreover, daily stress in TNBC mice caused further mitochondrial dysfunction, increased oxidative phosphorylation, and altered lipid metabolism. Importantly, over half of the mammary tumours that initially developed spontaneously regressed after 7-9 weeks in these young immunocompetent mice. Tumour regression inhibited TNFα increases in the PFC. However, the hippocampal proteomes of tumour-bearing mice were largely similar to mice in which tumours regressed, suggesting that spontaneous regression of breast cancer confers lasting physiological dysregulations that impact hippocampal protein expression. This study in mice may help to identify molecular mechanisms responsible for long-term memory impairments in cancer survivors and reveal novel drug targets for cancer-related cognitive impairment.

Unleashing the potential: 40 Hz multisensory stimulation therapy for cognitive impairment

Cognitive impairment encompasses a spectrum of disorders marked by acquired deficits in cognitive function, potentially leading to diminished daily functioning and work capacity, often accompanied by psychiatric and behavioral disturbances. Alzheimer's disease (AD) and Post-stroke cognitive impairment (PSCI) are significant causes of cognitive decline. With the global population getting older, AD and PSCI are becoming major health concerns, underscoring the critical necessity for successful treatment options. In recent years, various non-invasive biophysical stimulation techniques, including ultrasound, light, electric, and magnetic stimulation, have been developed for the treatment of central nervous system diseases. Preliminary clinical studies have demonstrated the feasibility and safety of these techniques. This review discuss the impact of 40 Hz multisensory stimulation on cerebral function, behavioral outcomes, and disease progression in both animal models and individuals exhibiting cognitive deficits, such as AD and PSCI. Furthermore, it summarizes the potential neural pathways involved in this therapeutic modality by synthesizing evidence from a variety of studies within the field. Subsequently, it evaluates the existing constraints of this technique and underscores the potential advantages of 40 Hz multisensory stimulation therapy for individuals with cognitive deficits, with the goal of enhancing the management and care of AD and PSCI.

The crosstalk between CNS resident glial cells and peripheral immune cells is critical for age-dependent demyelination and subsequent remyelination

White-matter diseases like multiple sclerosis begin in young adulthood. Aging, being a risk factor, contributes to the progression of these diseases and makes neurological disabilities worsen. Aging causes white matter alteration due to myelin loss, axonal degeneration, and hyperintensities, resulting in cognitive impairment and neurological disorders. Aging also negatively affects central nervous system resident glial cells and peripheral immune cells, contributing to myelin degeneration and diminished myelin renewal process. Restoration of myelin failure with aging accelerates the progression of cognitive decline. This review will mainly focus on how age-related altered functions of glial and peripheral cells will affect myelin sheath alteration and myelin restoration. This understanding can give us insights into the underlying mechanisms of demyelination and failure of remyelination with aging concerning altered glial and peripheral immune cell function and their crosstalk. Also, we will explain the therapeutic strategies to enhance the remyelination process of an aging brain to improve the cognitive health of an aging person.

Microglial cGAS Deletion Preserves Intercellular Communication and Alleviates Amyloid-β-Induced Pathogenesis of Alzheimer's Disease

Innate immune activation plays a crucial role in the pathogenesis of Alzheimer's disease (AD) and related dementias (ADRD). The cytosolic DNA sensing pathway, involving cGAMP synthase (cGAS) and Stimulator of Interferon Genes (STING), has emerged as a key mediator of neurodegenerative diseases. However, the precise mechanisms through which cGAS activation influences AD progression remain poorly understood. In this study, we observed significant up-regulation of cGAS-STING signaling pathway in AD. Notably, this increase is primarily attributed to microglia, rather than non-microglial cell types. Using an inducible, microglia-specific cGAS knockout mouse model in the 5xFAD background, we demonstrated that deleting microglial cGAS at the onset of amyloid-β (Aβ) pathology profoundly restricts plaque accumulation and protects mice from Aβ-induced cognitive impairment. Mechanistically, our study revealed cGAS promotes plaque-associated microglia accumulation and is essential for inflammasome activation. Moreover, we showed that restricting cGAS-mediated innate immunity is crucial for preserving inter-cellular communication in the brain and induces pleiotrophin, a neuroprotective factor. These findings offer novel insights into the specific roles of the innate immune system in AD employing a cell-type-specific approach. The conclusions provide a foundation for targeted interventions to modulate the microglial cGAS-STING signaling pathway, offering promising therapeutic strategy for AD treatment.

Liposomal Lactoferrin Reduces Brain Neuroinflammation in Rats and Alleviates Jetlag and Improves Sleep Quality After Long-Haul Travel

Insufficient sleep and circadian misalignment increase inflammatory agents. This triggers neuroinflammation and can result in health issues including depression, dementia, lifestyle-related diseases, and industrial accidents. Lactoferrin (LF) confers neuroprotective effects, which are derived from its anti-inflammatory, antioxidant, and iron metabolic properties; however, its roles in acute neuroinflammation and circadian rhythm disruption are yet to be elucidated. Therefore, we aimed to test the effects of LF on rat neuroinflammation and sleep and jetlag in humans. Rats received 7 days of an oral liposomal bovine LF (L-bLF) or vehicle followed by polyriboinosinic:polyribocytidylic acid (poly I:C) peritoneal injections (n = 5-6). Compared with the rats given poly I:C only, the rats given L-bLF and poly I:C had lower Il1b, Tnf, Casp1, Nfe212, Gclm, and Sod2 expression in the hippocampus. This open-label pilot study was carried out on tour conductors performing regular international tour responsibilities, and the data were compared between the initial tour without L-bLF intake and the subsequent tour with L-bLF intake. In the tour with L-bLF intake, L-bLF administration started from one week before the trip and was continued during the trip. In both periods, the tour conductors experienced limited sleep; however, both subjective and objective sleep quality was significantly better with the oral L-bLF intake than without. Overall, we found that prophylactic L-bLF supplementation reduced neuroinflammation in rat hippocampi and improved sleep quality and jetlag in tour conductors.

Interconnections of screen time with neuroinflammation

The increasing prevalence of screen time among modern citizens has raised concerns regarding its potential impact on neuroinflammation and overall brain health. This review examines the complex interconnections between screen time and neuroinflammatory processes, particularly in children and adolescents. We analyze existing literature that explores how excessive digital media use can lead to alterations in neurobiological pathways, potentially exacerbating inflammatory responses in the brain. Key findings suggest that prolonged exposure to screens may contribute to neuroinflammation through mechanisms such as disrupted sleep patterns, diminished cognitive engagement, and increased stress levels. Similarly, we discuss the implications of these findings for mental health and cognitive development, emphasizing the need for a balanced approach to screen time. This review highlights the necessity for further research to elucidate the causal relationships and underlying mechanisms linking screen time and neuroinflammation, thereby informing guidelines for healthy media consumption.

Prenatal inflammation exacerbates hyperoxia-induced neonatal brain injury

BACKGROUND

Premature born infants are at high risk to develop white matter injury (WMI). Hyperoxia and perinatal inflammation are main risk factors for preterm birth and associated brain injury. To date the majority of experimental studies have focused on isolated insults. However, clinically, WMI injury is a multifactorial disorder caused by a variety of triggers. To establish a clinically relevant rodent model of WMI, we combined prenatal inflammation with postnatal hyperoxia to investigate individual, and additive or synergistic effects on inflammatory processes, myelination and grey matter development.

METHODS

At embryonic day 20, pregnant Wistar rat dams received either a single intraperitoneal injection of 100 µg/ kg lipopolysaccharide (LPS) or sodium chloride. Offspring were either exposed to hyperoxia (80% O2) or normoxia (21% O2) from postnatal day 3 to 5. Animals were sacrificed immediately after hyperoxia or 6 days later, corresponding to term-equivalent age. White and grey matter development and neuroinflammatory responses were investigated at cellular and molecular levels applying immunohistochemistry, western blotting, real time PCR in brain tissues and multiplex protein expression analysis on serum samples.

RESULTS

Prenatal inflammation combined with postnatal hyperoxia resulted in reduced body weight and length in the offspring, accompanied by increased serum leptin levels at term equivalent age. The altered body parameters, like body weight, were associated with decreased brain volume, thinning of deep cortical layers and hypomyelination. As potential underlying mechanisms, we identified severe myelination deficits and an increased microglia activation associated with elevated inflammatory cytokine expression in brain tissues, while peripheral cytokine levels were reduced. Interestingly, effects on body size were mainly mediated by prenatal LPS, independent of hyperoxia, while oligodendrocyte degeneration was mainly induced by postnatal hyperoxia, independent of prenatal inflammation. However, for the majority of pathological changes, including brain size, myelination deficits, microglia activation and inflammatory cytokine expression, additive or synergistic effects were detected.

CONCLUSION

Prenatal inflammation combined with postnatal hyperoxia results in aggravated myelination deficits and inflammatory responses compared to single insults, making it an ideal model to improve our understanding of the complex pathophysiology underlying WMI and to evaluate urgently needed therapies.

Ligand-receptor interactions: A key to understanding microglia and astrocyte roles in epilepsy

Epilepsy continues to pose significant social and economic challenges on a global scale. Existing therapeutic approaches predominantly revolve around neurocentric mechanisms, and fail to control seizures in approximately one-third of patients. This underscores the pressing need for novel and complementary treatment approaches to address this gap. An increasing body of literature points to a role for glial cells, including microglia and astrocytes, in the pathogenesis of epilepsy. Notably, microglial cells, which serve as pivotal inflammatory mediators within the epileptic brain, have received increasing attention over recent years. These immune cells react to epileptogenic insults, regulate neuronal processes, and play diverse roles during the process of epilepsy development. Additionally, astrocytes, another integral non-neuronal brain cells, have garnered increasing recognition for their dynamic contributions to the pathophysiology of epilepsy. Their complex interactions with neurons and other glial cells involve modulating synaptic activity and neuronal excitability, thereby influencing the aberrant networks formed during epileptogenesis. This review explores the alterations in microglial and astrocytic function and their mechanisms of communication following an epileptogenic insult, examining their contribution to epilepsy development. By comprehensively studying these mechanisms, potential avenues could emerge for refining therapeutic strategies and ameliorating the impact of this complex neurological disease.

Brain interleukins and Alzheimer's disease

The central nervous system (CNS) is immune-privileged by several immuno-modulators as interleukins (ILs). ILs are cytokines secreted by immune cells for cell-cell signaling communications and affect the functions of the CNS. ILs were reported to orchestrate different molecular and cellular mechanisms of both physiological and pathological events, through overproduction or over-expression of their receptors. They interact with numerous receptors mediating pro-inflammatory and/or anti-inflammatory actions. Interleukins have been implicated to participate in neurodegenerative diseases. They play a critical role in Alzheimer's disease (AD) pathology which is characterized by the over-production of pro-inflammatory ILs. These may aggravate neurodegeneration, in addition to their contribution to detrimental mechanisms as oxidative stress, and excitotoxicity. However, recent research on the relation between ILs and AD revealed major discrepancies. Most of the major ILs were shown to play both pro- and anti-inflammatory roles in different experimental settings and models. The interactions between different ILs through shared pathways also add to the difficulty of drawing solid conclusions. In addition, targeting the different ILs has not yielded consistent results. The repeated failures of therapeutic drugs in treating AD necessitate the search for novel agents targeting multiple mechanisms of the disease pathology. In this context, the understanding of interleukins and their roles throughout the disease progression and interaction with other systems in the brain may provide promising therapeutic targets for the prevention or treatment of AD.

Psychedelics in neuroinflammation: Mechanisms and therapeutic potential

Neuroinflammation is a critical factor in the pathogenesis of various neurodegenerative and psychiatric disorders, including Alzheimer's disease, Parkinson's disease, and major depressive disorder. Psychedelics, such as psilocybin, lysergic acid diethylamide (LSD), and dimethyltryptamine (DMT), have demonstrated promising therapeutic effects on neuroinflammation, primarily through interactions with serotonin (5-HT) receptors, particularly the 5-HT2A receptor. Activation of these receptors by psychedelics modulates the production of pro-inflammatory cytokines, regulates microglial activity, and shifts the balance between neurotoxic and neuroprotective metabolites. Additionally, psychedelics affect critical signaling pathways, including the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), and mechanistic target of rapamycin (mTOR) pathways, promoting neuroplasticity and exerting anti-inflammatory effects. Beyond the serotonergic system, other neurotransmitter systems-including the glutamatergic, dopaminergic, noradrenergic, gamma-aminobutyric acid (GABAergic), and cholinergic systems-also play significant roles in mediating the effects of psychedelics. This review examines the intricate mechanisms by which psychedelics modulate neuroinflammation and underscores their potential as innovative therapeutic agents for treating neuroinflammatory and neuropsychiatric disorders.

P2X7R antagonism suppresses long-lasting brain hyperexcitability following traumatic brain injury in mice

Purpose: Post-traumatic epilepsy (PTE) is one of the most common life-quality reducing consequences of traumatic brain injury (TBI). However, to date there are no pharmacological approaches to predict or to prevent the development of PTE. The P2X7 receptor (P2X7R) is a cationic ATP-dependent membrane channel that is expressed throughout the brain. While increasing evidence suggests a role for the P2X7R during seizures and epilepsy, it is unclear if changes in P2X7R expression can predict TBI-induced epilepsy development, and whether P2X7R antagonism can protect against long-lasting brain hyperexcitability caused by TBI. Methods: TBI was induced in adult male mice using the controlled cortical impact model (CCI). To test the anti-epileptogenic effects of P2X7R antagonism, mice were treated with brain-penetrant P2X7R antagonists JNJ-54175446 (30 mg/kg) or AFC-5128 (30 mg/kg) for 7 days post-CCI. The cell-type specific effects of P2X7Rs on TBI-induced hyperexcitability were analyzed in mice lacking exon 2 of the P2rx7 gene selectively in microglia (P2rx7:Cx3cr1-Cre). Static positron emission tomography (PET) via an intravenous injection of the P2X7R radioligand 18F-JNJ-64413739 and magnetic resonance imaging (MRI) were conducted twice during the first- and third-week post-injury. Results: Following TBI, while there were no obvious changes in P2X7R protein levels in the ipsilateral hippocampus post-injury, there was a delayed increase in P2X7R protein levels in the ipsilateral cortex at 3 months post-injury. Treatment with P2X7R antagonists shortly after TBI reduced long-lasting brain hyperexcitability, reduced cortical contusion volume, and normalized injury-induced hyperactivity to control sham-levels at 3 weeks post-TBI. Notably, mice lacking P2rx7 in microglia had an increased seizure threshold after TBI, suggesting that P2X7R contributed to brain hyperexcitability via its effects on microglia. Finally, P2X7R radioligand uptake after TBI correlated with seizure threshold at 3 weeks post-injury. Conclusions: Our results demonstrate the antiepileptogenic potential of P2X7R antagonism to prevent TBI-induced epilepsy and indicate that P2X7R-based PET imaging may be a useful diagnostic tool to identify people at risk of developing PTE.

Inflammatory biomarkers profiles and cognition among older adults

Inflammation plays a major role in cognitive aging. Most studies on peripheral inflammation and cognitive aging focused on selected major inflammatory biomarkers. However, inflammatory markers are regulated and influenced by each other, and it is therefore important to consider a more comprehensive panel of markers to better capture diverse immune pathways and characterize the overall inflammatory profile of individuals. We explored 23 circulating inflammatory biomarkers using data from 1,743 participants without dementia (≥ 65 years-old) from the community-based, multiethnic Washington Heights Inwood Columbia Aging Project. Using principal component analysis (PCA), we developed six inflammatory profiles (PC-1 to PC-6) based on these 23 biomarkers and tested the association of resulting inflammatory profile with cognitive decline, over up to 12 years of follow-up. PC-1 described a pro-inflammatory profile characterized by high positive loadings for pro-inflammatory biomarkers. A higher PC-1 score was associated with lower baseline cognitive performances. No association of this profile with cognitive decline was observed in longitudinal analysis. However, PC-5 characterized by high PDGF-AA and RANTES was associated with a faster cognitive decline. Among older adults, a circulating pro-inflammatory immune profile is associated with lower baseline cognitive performance, and some specific pro-inflammatory cytokines might be associated with faster cognitive decline.

Targeting Cytokine-Mediated Inflammation in Brain Disorders: Developing New Treatment Strategies

Cytokine-mediated inflammation is increasingly recognized for playing a vital role in the pathophysiology of a wide range of brain disorders, including neurodegenerative, psychiatric, and neurodevelopmental problems. Pro-inflammatory cytokines such as interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) cause neuroinflammation, alter brain function, and accelerate disease development. Despite progress in understanding these pathways, effective medicines targeting brain inflammation are still limited. Traditional anti-inflammatory and immunomodulatory drugs are effective in peripheral inflammatory illnesses. Still, they face substantial hurdles when applied to the central nervous system (CNS), such as the blood-brain barrier (BBB) and unwanted systemic effects. This review highlights the developing treatment techniques for modifying cytokine-driven neuroinflammation, focusing on advances that selectively target critical cytokines involved in brain pathology. Novel approaches, including cytokine-specific inhibitors, antibody-based therapeutics, gene- and RNA-based interventions, and sophisticated drug delivery systems like nanoparticles, show promise with respect to lowering neuroinflammation with greater specificity and safety. Furthermore, developments in biomarker discoveries and neuroimaging techniques are improving our ability to monitor inflammatory responses, allowing for more accurate and personalized treatment regimens. Preclinical and clinical trial data demonstrate the therapeutic potential of these tailored techniques. However, significant challenges remain, such as improving delivery across the BBB and reducing off-target effects. As research advances, the creation of personalized, cytokine-centered therapeutics has the potential to alter the therapy landscape for brain illnesses, giving patients hope for better results and a higher quality of life.

Spatial distribution-based progression of spinal cord injury pathology: a key role for neuroimmune cells

An external trauma, illness, or other pathological cause can harm the structure and function of the spinal cord, resulting in a significant neurological disorder known as spinal cord injury (SCI). In addition to impairing movement and sensory functions, spinal cord injury (SCI) triggers complex pathophysiological responses, with the spatial dynamics of immune cells playing a key role. The inflammatory response and subsequent healing processes following SCI are profoundly influenced by the spatial distribution and movement of immune cells. Despite significant advances in both scientific and clinical research, SCI therapy still faces several challenges. These challenges primarily stem from our limited understanding of the spatial dynamics of immune cell distribution and the processes that regulate their interactions within the microenvironment following injury. Therefore, a comprehensive investigation into the spatial dynamics of immune cells following SCI is essential to uncover their mechanisms in neuroinflammation and repair, and to develop novel therapeutic strategies.

Recent Advances in the Mechanisms of Postoperative Neurocognitive Dysfunction: A Narrative Review

Postoperative neurocognitive dysfunction (PND) is a prevalent and debilitating complication in elderly surgical patients, characterized by persistent cognitive decline that negatively affects recovery and quality of life. As the aging population grows, the rising number of elderly surgical patients has made PND an urgent clinical challenge. Despite increasing research efforts, the pathophysiological mechanisms underlying PND remain inadequately characterized, underscoring the need for a more integrated framework to guide targeted interventions. To better understand the molecular mechanisms and therapeutic targets of PND, this narrative review synthesized evidence from peer-reviewed studies, identified through comprehensive searches of PubMed, Embase, Cochrane Library, and Web of Science. Key findings highlight neuroinflammation, oxidative stress, mitochondrial dysfunction, neurotransmitter imbalances, microvascular changes, and white matter lesions as central to PND pathophysiology, with particular parallels to encephalocele- and sepsis-associated cognitive impairments. Among these, neuroinflammation, mediated by pathways such as the NLRP3 inflammasome and blood-brain barrier disruption, emerges as a pivotal driver, triggering cascades that exacerbate neuronal injury. Oxidative stress and mitochondrial dysfunction synergistically amplify these effects, while neurotransmitter imbalances and microvascular alterations, including white matter lesions, contribute to synaptic dysfunction and cognitive decline. Anesthetic agents modulate these interconnected pathways, exhibiting both protective and detrimental effects. Propofol and dexmedetomidine demonstrate neuroprotective properties by suppressing neuroinflammation and microglial activation, whereas inhalational anesthetics like sevoflurane intensify oxidative stress and inflammatory responses. Ketamine, with its anti-inflammatory potential, offers promise but requires further evaluation to determine its long-term safety and efficacy. By bridging molecular insights with clinical practice, this review highlights the critical role of personalized anesthetic strategies in mitigating PND and improving cognitive recovery in elderly surgical patients. It aims to inform future research and clinical decision-making to address this multifaceted challenge.

Human Microglia-Like Cells Differentiated from Monocytes with GM-CSF and IL-34 Show Phagocytosis of α-Synuclein Aggregates and C/EBPβ-Dependent Proinflammatory Activation

Microglia, the main resident immune cells in the central nervous system, are implicated in the pathogenesis of various neurological disorders. Much of our knowledge on microglial biology was obtained using rodent microglial cultures. To understand the role of microglia in human disease, reliable in vitro models of human microglia are necessary. Monocyte-derived microglia-like cells (MDMi) are a promising approach. This study aimed to characterize MDMi cells generated from adult human monocytes using granulocyte-macrophage colony-stimulating factor and interleukin-34. To this end, 49 independent cultures of MDMI were prepared, and various methodological and functional studies were performed. We show that with this protocol, adult human monocytes develop into microglia-like cells, a coating is unnecessary, and high cell density seeding is preferable. When compared to monocytes, MDMi upregulate the expression of many, but not all, microglial markers, indicating that, although these cells display a microglia-like phenotype, they cannot be considered bona fide human microglia. At the functional level, MDMi phagocytose α-synuclein aggregates and responds to lipopolysaccharide (LPS) by nuclear translocation of the transcription factor nuclear factor-kappaB (NFkappaB) and the upregulation of proinflammatory genes. Finally, a long-lasting silencing of the transcription factor CCAAT/enhancer protein β (C/EBPβ) was achieved by small interfering RNA, resulting in the subsequent downregulation of proinflammatory genes. This supports the hypothesis that C/EBPβ plays a key role in proinflammatory gene program activation in human microglia. Altogether, this study sheds new light on the properties of MDMi cells and supports these cells as a promising in vitro model for studying adult human microglia-like cells.

Epidemic Zika virus strains from the Asian lineage induce an attenuated fetal brain pathogenicity

The 2015-2016 Zika virus (ZIKV) outbreak in the Americas revealed the ability of ZIKV from the Asian lineage to cause birth defects, generically called congenital Zika syndrome (CZS). Notwithstanding the long circulation history of Asian ZIKV, no ZIKV-associated CZS cases were reported prior to the outbreaks in French Polynesia (2013) and Brazil (2015). Whether the sudden emergence of CZS resulted from an evolutionary event of Asian ZIKV has remained unclear. We performed a comparative analysis of the pathogenicity of pre-epidemic and epidemic Asian ZIKV strains in mouse embryonic brains using a female immunocompetent intraplacental infection mouse model. All studied Asian ZIKV strains are neurovirulent, but pre-epidemic strains are consistently more pathogenic in the embryos than their epidemic equivalents. Pathogenicity is not directly linked to viral replication. By contrast, an influx of macrophages/microglial cells is noted in infected fetal brains for both pre-epidemic and epidemic ZIKV strains. Moreover, all tested ZIKV strains trigger an immunological response, whereby the intensity of the response differs between strains, and with epidemic ZIKV strains generally mounting a more attenuated immunostimulatory response. Our study reveals that Asian ZIKV strains evolved towards pathogenic attenuation, potentially resulting in CZS emergence in neonates rather than premature death in utero.

The Critical Role of Autophagy and Phagocytosis in the Aging Brain

As the organism ages, there is a decline in effective energy supply, and this retards the ability to elaborate new proteins. The consequences of this are especially marked in the gradual decline in brain function. The senescence of cells and their constituent organelles is ultimately the cause of aging of the entire nervous system. What is less immediately obvious is that brain aging is also accompanied by the failure of catabolic events that lead to the removal of non-functional cells and ineffective subcellular components. The removal of non-working cellular and subcellular elements within the brain is essential in order to allow the appearance of fresh cells and organelles with a full range of capacities. Thus, the maintenance of operative mechanisms for the dispersal of failed tissue components is important, and its diminished capacity with aging is a significant contributory factor to the onset and progression of age-related neurological disorder. This report discusses the mechanisms underlying autophagy and phagocytosis and how these can be adversely modulated as aging proceeds. The means by which the effective recycling of cellular components may be reinstated in the aged brain are considered.

Molecular intersections of traumatic brain injury and Alzheimer's disease: the role of ADMSC-derived exosomes and hub genes in microglial polarization

Traumatic brain injury (TBI) is a significant contributor to global mortality and morbidity, with emerging evidence indicating a heightened risk of developing Alzheimer's disease (AD) following TBI. This study aimed to explore the molecular intersections between TBI and AD, focusing on the role of adipose mesenchymal stem cell (ADMSC)-derived exosomes and hub genes involved in microglial polarization. Transcriptome profiles from TBI (GSE58485) and AD (GSE74614) datasets were analyzed to identify differentially expressed genes (DEGs). The hub genes were validated in independent datasets (GSE180811 for TBI and GSE135999 for AD) and localized to specific cell types using single-cell RNA (scRNA) sequencing data (GSE160763 for TBI and GSE224398 for AD). Experimental validation was conducted to investigate the role of these genes in microglial polarization using cell culture and ADMSC-derived exosomes interventions. Our results identified three hub genes-Bst2, B2m, and Lgals3bp-that were upregulated in both TBI and AD, with strong associations to inflammation, neuronal apoptosis, and tissue repair processes. scRNA sequencing revealed that these genes are predominantly expressed in microglia, with increased expression during M1 polarization. Knockdown of these genes reduced M1 polarization and promoted M2 phenotype in microglia. Additionally, ADMSC-derived exosomes attenuated M1 polarization and downregulated the expression of hub genes. This study provides novel insights into the shared molecular pathways between TBI and AD, highlighting potential therapeutic targets for mitigating neuroinflammation and promoting recovery in both conditions.

New insights into protein-protein interaction modulators in drug discovery and therapeutic advance

Protein-protein interactions (PPIs) are fundamental to cellular signaling and transduction which marks them as attractive therapeutic drug development targets. What were once considered to be undruggable targets have become increasingly feasible due to the progress that has been made over the last two decades and the rapid technological advances. This work explores the influence of technological innovations on PPI research and development. Additionally, the diverse strategies for discovering, modulating, and characterizing PPIs and their corresponding modulators are examined with the aim of presenting a streamlined pipeline for advancing PPI-targeted therapeutics. By showcasing carefully selected case studies in PPI modulator discovery and development, we aim to illustrate the efficacy of various strategies for identifying, optimizing, and overcoming challenges associated with PPI modulator design. The valuable lessons and insights gained from the identification, optimization, and approval of PPI modulators are discussed with the aim of demonstrating that PPI modulators have transitioned beyond early-stage drug discovery and now represent a prime opportunity with significant potential. The selected examples of PPI modulators encompass those developed for cancer, inflammation and immunomodulation, as well as antiviral applications. This perspective aims to establish a foundation for the effective targeting and modulation of PPIs using PPI modulators and pave the way for future drug development.

Rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone prevent amnesia induced in scopolamine zebrafish (Danio rerio) model by increasing the mRNA expression of bdnf, npy, egr-1, nfr2α, and creb1 genes

The increasing attention towards age-related diseases has generated significant interest in the concept of cognitive dysfunction associated with Alzheimer's disease (AD). Certain limitations are associated with the current therapies, and flavonoids have been reported to exhibit multiple biological activities and anti-AD effects in several AD models owing to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties. In this study, we performed an initial in silico predictions of the pharmacokinetic properties of three flavonoids (rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone). Subsequently, we evaluated the antiamnesic and antioxidant potential of flavonoids in concentrations of 1, 3, and 5 μg/L in scopolamine (100 μM)-induced amnesic zebrafish (Danio rerio) model. Zebrafish behavior was analyzed by novel tank diving test (NTT), Y-maze, and novel object recognition test (NOR). Acetylcholinesterase (AChE) activity, brain antioxidant status and the expression of bdnf, npy, egr1, nrf2α, creb1 genes, and CREB-1 protein level was measured to elucidate the underlying mechanism of action. Our flavonoids improved memory and decreased anxiety-like behavior of scopolamine-induced amnesia in zebrafish. Also, the studied flavonoids reduced AChE activity and brain oxidative stress and upregulated the gene expression, collectively contributing to neuroprotective properties. The results of our study add new perspectives on the properties of flavonoids to regulate the evolution of neurodegenerative diseases, especially AD, by modulating the expression of genes involved in the regulation of synaptic plasticity, axonal growth, and guidance, sympathetic and vagal transmission, the antioxidant response and cell proliferation and growth.

Environmental exposures and familial background alter the induction of neuropathology and inflammation after SARS-CoV-2 infection

Basal ganglia disease has been reported as a post-infection sequela of several viruses, with documentation of this phenomenon from the H1N1 Spanish flu to the recent COVID-19 (SARS-CoV-2) pandemic. SARS-CoV-2 infection leads to multisystem deficits, including those affecting the nervous system. Here, we investigated whether a SARS-CoV-2 infection alone increases the susceptibility to develop parkinsonian phenotypes in C57BL/6J mice expressing the human ACE2 receptor, or in addition to two well-known toxin exposures, MPTP and paraquat. Additionally, we examined mice carrying a G2019S mutation in the LRRK2 gene. We also examined if vaccination with either an mRNA- or protein-based vaccine can alter any observed neuropathology. We find that the infection with the WA-1/2020 (alpha) or omicron B1.1.529 strains in ACE2 and G2019S LRRK2 mice both synergize with a subtoxic exposure to the mitochondrial toxin MPTP to induce neurodegeneration and neuroinflammation in the substantia nigra. This synergy appears toxin-dependent since we do not observe this following exposure to the direct redox-inducing compound paraquat. This synergistic neurodegeneration and neuroinflammation is rescued in WT mice that were vaccinated using either mRNA- and protein- based vaccines directed against the Spike protein of the SARS-CoV-2 virus. However, in the G2019S LRRK2 mutant mice, we find that only the protein-based vaccine but not the mRNA- based vaccine resulted in a rescue of the SARS-CoV-2 mediated neuropathology. Taken together, our results highlight the role of both environmental exposures and familial background on the development of parkinsonian pathology secondary to viral infection and the benefit of vaccines in reducing these risks.

Cross-talk between adipose tissue and microbiota-gut-brain-axis in brain development and neurological disorder

The gut microbiota is an important factor responsible for the physiological processes as well as pathogenesis of host. The communication between central nervous system (CNS) and microbiota occurs by different pathways i.e., chemical, neural, immune, and endocrine. Alteration in gut microbiota i.e., gut dysbiosis causes alteration in the bidirectional communication between CNS and gut microbiota and linked to the pathogenesis of neurological and neurodevelopmental disorder. Therefore, now-a-days microbiota-gut-brain-axis (MGBA) has emerged as therapeutic target for the treatment of metabolic disorder. But, experimental data available on MGBA from basic research has limited application in clinical study. In present study we first summarized molecular mechanism of microbiota interaction with brain physiology and pathogenesis via collecting data from different sources i.e., PubMed, Scopus, Web of Science. Furthermore, evidence shows that adipose tissue (AT) is active during metabolic activities and may also interact with MGBA. Hence, in present study we have focused on the relationship among MGBA, brown adipose tissue, and white adipose tissue. Along with this, we have also studied functional specificity of AT, and understanding heterogeneity among MGBA and different types of AT. Therefore, molecular interaction among them may provide therapeutic target for the treatment of neurological disorder.

Neuroimmune communication of the cholinergic system in gut inflammation and autoimmunity

Neuroimmune communication in the body forms a bridge between two central regulatory systems of the body, i.e., nervous and immune systems. The cholinergic system is a crucial modulatory neurotransmitter in the central and peripheral nervous system. It includes the neurotransmitter acetylcholine (ACh), the enzyme required for the synthesis of ACh (choline acetyltransferase, ChAT), the enzyme required for its degradation (acetylcholinesterase, AChE), and cholinergic receptors (Nicotinic acetylcholine receptors and muscarinic acetylcholine receptors). The cholinergic system in neurons is well known for its role in cognitive function, sensory perception, motor control, learning, and memory processes. It has been shown that the non-neuronal cholinergic system (NNCS) is present in various tissues and immune cells and forms a neuroimmune communications system. In the present review, we discussed the NNCS on immune cells, its role in homeostasis and inflammatory reactions in the gut, and how it can be exploited in treating inflammatory responses.

Targeting inflammation and gut microbiota with antibacterial therapy: Implications for central nervous system health

The complex symbiotic relationship between inflammation, the gut microbiota, and the central nervous system (CNS) has become a pivotal focus of contemporary biomedical research. Inflammation, as a physiological defense mechanism, plays a dual role as both a protective and pathological factor, and is intricately associated with gut microbiota homeostasis, often termed the "second brain." The gutbrain axis (GBA) exemplifies this multifaceted interaction, where gut health exerts significantly regulatory effects on CNS functions. Antibacterial therapies represent both promising and challenging strategies for modulating inflammation and gut microbiota composition to confer CNS benefits. However, while such therapies may exert positive modulatory effects on the gut microbiota, they also carry the potential to disrupt microbial equilibrium, potentially exacerbating neurological dysfunction. Recent advances have provided critical insights into the therapeutic implications of antibacterial interventions; nevertheless, the application of these therapies in the context of CNS health warrants a judicious and evidence-based approach. As research progresses, deeper investigation into the microbial-neural interface is essential to fully realize the potential of therapies targeting inflammation and the gut microbiota for CNS health. Future efforts should focus on refining antibacterial interventions to modulate the gut microbiota while minimizing disruption to microbial balance, thereby reducing risks and enhancing efficacy in CNS-related conditions. In conclusion, despite challenges, a more comprehensive understanding of the GBA, along with precise modulation through targeted antibacterial therapies, offers significant promise for advancing CNS disorder treatment. Continued research in this area will lead to innovative interventions and improved patient outcomes.

Microglia regulate motor neuron plasticity via reciprocal fractalkine and adenosine signaling

We report an important role for microglia in regulating neuroplasticity within phrenic motor neurons. Brief episodes of low oxygen (acute intermittent hypoxia; AIH) elicit a form of respiratory motor plasticity known as phrenic long-term facilitation (pLTF) that is regulated by the balance of competing serotonin vs adenosine-initiated cellular mechanisms. Serotonin arises from brainstem raphe neurons, but the source of adenosine is unknown. We tested if hypoxic episodes initiate phrenic motor neuron to microglia fractalkine signaling that evokes extracellular adenosine formation using a well-defined neurophysiology preparation in male rats. With moderate AIH, phrenic motor neuron adenosine 2A receptor activation undermines serotonin-dominant pLTF whereas severe AIH induces pLTF by the adenosine-dependent mechanism. Consequently, phrenic motor neuron fractalkine knockdown, microglial fractalkine receptor inhibition, and microglial ablation enhance moderate AIH, but suppress severe AIH-induced pLTF. We conclude, microglia play important roles in healthy spinal cords, regulating plasticity in motor neurons responsible for breathing.

Irisin's emerging role in Parkinson's disease research: A review from molecular mechanisms to therapeutic prospects

Parkinson's disease (PD), a neurodegenerative disorder characterized by impaired motor function, is typically treated with medications and surgery. However, recent studies have validated physical exercise as an effective adjunct therapy, significantly improving both motor and non-motor symptoms in PD patients. Irisin, a myokine, has garnered increasing attention for its beneficial effects on the nervous system. Research has shown that irisin plays a crucial role in regulating metabolic balance, optimizing autophagy, maintaining mitochondrial quality, alleviating oxidative stress and neuroinflammation, and regulating cell death-all processes intricately linked to the pathogenesis of PD. This review examines the mechanisms through which irisin may counteract PD, provides insights into its biological effects, and considers its potential as a target for therapeutic strategies.

Microglial depletion rescues spatial memory impairment caused by LPS administration in adult mice

Recent studies have highlighted the importance of microglia, the resident macrophages in the brain, in regulating cognitive functions such as learning and memory in both healthy and diseased states. However, there are conflicting results and the underlying mechanisms are not fully understood. In this study, we examined the effect of depleting adult microglia on spatial learning and memory under both physiological conditions and lipopolysaccharide (LPS)-induced neuroinflammation. Our results revealed that microglial depletion by PLX5622 caused mild spatial memory impairment in mice under physiological conditions; however, it prevented memory deficits induced by systemic LPS insult. Inactivating microglia through minocycline administration replicated the protective effect of microglial depletion on LPS-induced memory impairment. Furthermore, our study showed that PLX5622 treatment suppressed LPS-induced neuroinflammation, microglial activation, and synaptic dysfunction. These results strengthen the evidence for the involvement of microglial immunoactivation in LPS-induced synaptic and cognitive malfunctions. They also suggest that targeting microglia may be a potential approach to treating neuroinflammation-associated cognitive dysfunction seen in neurodegenerative diseases.

Gut Microbiota and Immune System Dynamics in Parkinson's and Alzheimer's Diseases

The gut microbiota, a diverse collection of microorganisms in the gastrointestinal tract, plays a critical role in regulating metabolic, immune, and cognitive functions. Disruptions in the composition of these microbial communities, termed dysbiosis, have been linked to various neurodegenerative diseases (NDs), such as Parkinson's disease (PD) and Alzheimer's disease (AD). One of the key pathological features of NDs is neuroinflammation, which involves the activation of microglia and peripheral immune cells. The gut microbiota modulates immune responses through the production of metabolites and interactions with immune cells, influencing the inflammatory processes within the central nervous system. This review explores the impact of gut dysbiosis on neuroinflammation, focusing on the roles of microglia, immune cells, and potential therapeutic strategies targeting the gut microbiota to alleviate neuroinflammatory processes in NDs.

Navigating the nano-bio immune interface: advancements and challenges in CNS nanotherapeutics

In recent years, significant advancements have been made in utilizing nanoparticles (NPs) to modulate immune responses within the central nervous system (CNS), offering new opportunities for nanotherapeutic interventions in neurological disorders. NPs can serve as carriers for immunomodulatory agents or platforms for delivering nucleic acid-based therapeutics to regulate gene expression and modulate immune responses. Several studies have demonstrated the efficacy of NP-mediated immune modulation in preclinical models of neurological diseases, including multiple sclerosis, stroke, Alzheimer's disease, and Parkinson's disease. While challenges remain, advancements in NPs engineering and design have led to the development of NPs using diverse strategies to overcome these challenges. The nano-bio interface with the immune system is key in the conceptualization of NPs to efficiently act as nanotherapeutics in the CNS. The biomolecular corona plays a pivotal role in dictating NPs behavior and immune recognition within the CNS, giving researchers the opportunity to optimize NPs design and surface modifications to minimize immunogenicity and enhance biocompatibility. Here, we review how NPs interact with the CNS immune system, focusing on immunosurveillance of NPs, NP-induced immune reprogramming and the impact of the biomolecular corona on NPs behavior in CNS immune responses. The integration of NPs into CNS nanotherapeutics offers promising opportunities for addressing the complex challenges of acute and chronic neurological conditions and pathologies, also in the context of preventive and rehabilitative medicine. By harnessing the nano-bio immune interface and understanding the significance of the biomolecular corona, researchers can develop targeted, safe, and effective nanotherapeutic interventions for a wide range of CNS disorders to improve treatment and rehabilitation. These advancements have the potential to revolutionize the treatment landscape of neurological diseases, offering promising solutions for improved patient care and quality of life in the future.

The interplay between epitranscriptomic RNA modifications and neurodegenerative disorders: Mechanistic insights and potential therapeutic strategies

Neurodegenerative disorders encompass a group of age-related conditions characterized by the gradual decline in both the structure and functionality of the central nervous system (CNS). RNA modifications, arising from the epitranscriptome or RNA-modifying protein mutations, have recently been observed to contribute significantly to neurodegenerative disorders. Specific modifications like N6-methyladenine (m6A), N1-methyladenine (m1A), 5-methylcytosine (m5C), pseudouridine and adenosine-to-inosine (A-to-I) play key roles, with their regulators serving as crucial therapeutic targets. These epitranscriptomic changes intricately control gene expression, influencing cellular functions and contributing to disease pathology. Dysregulation of RNA metabolism, affecting mRNA processing and noncoding RNA biogenesis, is a central factor in these diseases. This review underscores the complex relationship between RNA modifications and neurodegenerative disorders, emphasizing the influence of RNA modification and the epitranscriptome, exploring the function of RNA modification enzymes in neurodegenerative processes, investigating the functional consequences of RNA modifications within neurodegenerative pathways, and evaluating the potential therapeutic advancements derived from assessing the epitranscriptome.

Plastic Events of the Vestibular Nucleus: the Initiation of Central Vestibular Compensation

Vestibular compensation is a physiological response of the vestibular organs within the inner ear. This adaptation manifests during consistent exposure to acceleration or deceleration, with the vestibular organs incrementally adjusting to such changes. The molecular underpinnings of vestibular compensation remain to be fully elucidated, yet emerging studies implicate associations with neuroplasticity and signal transduction pathways. Throughout the compensation process, the vestibular sensory neurons maintain signal transmission to the central equilibrium system, facilitating adaptability through alterations in synaptic transmission and neuronal excitability. Notable molecular candidates implicated in this process include variations in ion channels and neurotransmitter profiles, as well as neuronal and synaptic plasticity, metabolic processes, and electrophysiological modifications. This study consolidates the current understanding of the molecular events in vestibular compensation, augments the existing research landscape, and evaluates contemporary therapeutic strategies. Furthermore, this review posits potential avenues for future research that could enhance our comprehension of vestibular compensation mechanisms.

The Dual Role of Amyloid Beta-Peptide in Oxidative Stress and Inflammation: Unveiling Their Connections in Alzheimer's Disease Etiopathology

Alzheimer's disease (AD) is a progressive neurodegenerative disease, and it is currently the seventh leading cause of death worldwide. It is characterized by the extracellular aggregation of the amyloid β-peptide (Aβ) into oligomers and fibrils that cause synaptotoxicity and neuronal death. Aβ exhibits a dual role in promoting oxidative stress and inflammation. This review aims to unravel the intricate connection between these processes and their contribution to AD progression. The review delves into oxidative stress in AD, focusing on the involvement of metals, mitochondrial dysfunction, and biomolecule oxidation. The distinct yet overlapping concept of nitro-oxidative stress is also discussed, detailing the roles of nitric oxide, mitochondrial perturbations, and their cumulative impact on Aβ production and neurotoxicity. Inflammation is examined through astroglia and microglia function, elucidating their response to Aβ and their contribution to oxidative stress within the AD brain. The blood-brain barrier and oligodendrocytes are also considered in the context of AD pathophysiology. We also review current diagnostic methodologies and emerging therapeutic strategies aimed at mitigating oxidative stress and inflammation, thereby offering potential treatments for halting or slowing AD progression. This comprehensive synthesis underscores the pivotal role of Aβ in bridging oxidative stress and inflammation, advancing our understanding of AD and informing future research and treatment paradigms.

The impact of neuroinflammation on neuronal integrity

Neuroinflammation, characterized by a complex interplay among innate and adaptive immune responses within the central nervous system (CNS), is crucial in responding to infections, injuries, and disease pathologies. However, the dysregulation of the neuroinflammatory response could significantly affect neurons in terms of function and structure, leading to profound health implications. Although tremendous progress has been made in understanding the relationship between neuroinflammatory processes and alterations in neuronal integrity, the specific implications concerning both structure and function have not been extensively covered, with the exception of perspectives on glial activation and neurodegeneration. Thus, this review aims to provide a comprehensive overview of the multifaceted interactions among neurons and key inflammatory players, exploring mechanisms through which inflammation influences neuronal functionality and structural integrity in the CNS. Further, it will discuss how these inflammatory mechanisms lead to impairment in neuronal functions and architecture and highlight the consequences caused by dysregulated neuronal functions, such as cognitive dysfunction and mood disorders. By integrating insights from recent research findings, this review will enhance our understanding of the neuroinflammatory landscape and set the stage for future interventions that could transform current approaches to preserve neuronal integrity and function in CNS-related inflammatory conditions.

Nuclear GAPDH in cortical microglia mediates cellular stress-induced cognitive inflexibility

We report a mechanism that underlies stress-induced cognitive inflexibility at the molecular level. In a mouse model under subacute cellular stress in which deficits in rule shifting tasks were elicited, the nuclear glyceraldehyde dehydrogenase (N-GAPDH) cascade was activated specifically in microglia in the prelimbic cortex. The cognitive deficits were normalized with a pharmacological intervention with a compound (the RR compound) that selectively blocked the initiation of N-GAPDH cascade without affecting glycolytic activity. The normalization was also observed with a microglia-specific genetic intervention targeting the N-GAPDH cascade. At the mechanistic levels, the microglial secretion of High-Mobility Group Box (HMGB), which is known to bind with and regulate the NMDA-type glutamate receptors, was elevated. Consequently, the hyperactivation of the prelimbic layer 5 excitatory neurons, a neural substrate for cognitive inflexibility, was also observed. The upregulation of the microglial HMGB signaling and neuronal hyperactivation were normalized by the pharmacological and microglia-specific genetic interventions. Taken together, we show a pivotal role of cortical microglia and microglia-neuron interaction in stress-induced cognitive inflexibility. We underscore the N-GAPDH cascade in microglia, which causally mediates stress-induced cognitive alteration.

Concentration of IL-1β, IL-7, IL-12, IL-17, CX3CL1, ITAC and relation with the seizure severity and sudden unexpected death in epilepsy patient

OBJECTIVE

Inflammation plays an important role in epilepsy. There is evidence for the relationship between proinflammatory cytokines and epilepsy. We aimed to detect the serum levels of multiple cytokines in epilepsy patients, looking for biological indicators, and providing a theoretical basis for the clinical diagnosis, treatment, and prognosis of epilepsy.

MATERIALS AND METHODS

In this study, 30 patients with drug-resistant epilepsy (DRE), 30 patients with well-controlled epilepsy (WCE), and 29 healthy controls (HC) were enrolled. Multi-proinflammatory cytokines were measured by LUMINX multi-factor detection.

RESULTS

The levels of IL-1β, IL-7, IL-12, and IL-17 were significantly elevated, and the levels of CX3CL1 and ITAC were significantly decreased in epilepsy patients compared with healthy controls. Furthermore, the level of IL-17 was significantly higher in the DRE group compared to WCE. We also found the ratio of IL-7/CX3CL discriminates accurately between patients and controls, with a ROC Area Under the Curve (AUC) of 0.963 (P<0.001). The levels of IL-1β, IL-7, IL-12, and IL-17 in the DRE group were positively correlated with the National Hospital Seizure Severity Scale (NHS3) scores (IL-1β, P = 0.029; IL-12, P = 0.039; IL-17, P = 0.004). IL-17 was positively correlated with seizure frequency (P = 0.050), while ITAC was negatively correlated with seizure frequency (P = 0.012) and Sudden Unexpected Death in Epilepsy-3 (SUDEP-3) scores (P = 0.023).

CONCLUSIONS

IL-1β, IL-12, and IL-17 may be used to predict seizure severity and the IL-7/CX3CL1 ratio may be a candidate biomarker for predicting epileptic seizures. While CX3CL1 and ITAC play anti-epileptic effects, ITAC may be used to assess the risk of SUDEP.

Inflammaging and Brain Aging

Progress made by the medical community in increasing lifespans comes with the costs of increasing the incidence and prevalence of age-related diseases, neurodegenerative ones included. Aging is associated with a series of morphological changes at the tissue and cellular levels in the brain, as well as impairments in signaling pathways and gene transcription, which lead to synaptic dysfunction and cognitive decline. Although we are not able to pinpoint the exact differences between healthy aging and neurodegeneration, research increasingly highlights the involvement of neuroinflammation and chronic systemic inflammation (inflammaging) in the development of age-associated impairments via a series of pathogenic cascades, triggered by dysfunctions of the circadian clock, gut dysbiosis, immunosenescence, or impaired cholinergic signaling. In addition, gender differences in the susceptibility and course of neurodegeneration that appear to be mediated by glial cells emphasize the need for future research in this area and an individualized therapeutic approach. Although rejuvenation research is still in its very early infancy, accumulated knowledge on the various signaling pathways involved in promoting cellular senescence opens the perspective of interfering with these pathways and preventing or delaying senescence.

Intravenous administration of human amnion-derived mesenchymal stem cells improves gait and sensory function in mouse models of spinal cord injury

Introduction

Spinal cord injury (SCI) leads to severe disabilities and remains a significant social and economic challenge. Despite advances in medical research, there are still no effective treatments for SCI. Human amnion-derived mesenchymal stem cells (hAMSCs) have shown potential due to their anti-inflammatory and neuroprotective effects. This study evaluates the therapeutic potential of intravenously administered hAMSCs in SCI models.

Methods

Three days after induction of SCI with forceps calibrated with a 0.2 mm gap, hAMSCs or vehicle were administered intravenously. Up to 4 weeks of SCI induction, motor function was assessed by scores on the Basso Mouse Locomotor Scale (BMS) and the Basso-Beattie-Bresnahan Scale (BBB), and sensory function by hindlimb withdrawal reflex using von Frey filaments. Six weeks after SCI induction, gait function was assessed using three-dimensional motion analysis. Immunohistochemistry, polymerase chain reaction (PCR), flow cytometry, and ELISA assay were performed to clarify the mechanisms of functional improvement.

Results

The hAMSC treatment significantly improved sensory response and gait function. In the SCI site, immunohistochemistry showed a reduction in Iba1-positive cells and PCR revealed decreased TNFα and increased BDNF levels in the hAMSC-treated group. In assessing the systemic inflammatory response, hAMSC treatment reduced monocytic bone marrow-derived suppressor cells (M-MDSCs) and Ly6C-positive inflammatory macrophages in the bone marrow by flow cytometry and serum NO levels by ELISA assay.

Discussion

This study demonstrates the therapeutic potential of the hAMSC in SCI, with improvements in gait and sensory functions and reduced inflammation both locally and systemically. The findings support further investigation of the hAMSC as a potential treatment for SCI, focusing on their ability to modulate inflammation and promote neuroprotection.

Potential Application of Plant-Derived Compounds in Multiple Sclerosis Management

Multiple sclerosis (MS) is a chronic autoimmune disorder characterized by inflammation, demyelination, and neurodegeneration, resulting in significant disability and reduced quality of life. Current therapeutic strategies primarily target immune dysregulation, but limitations in efficacy and tolerability highlight the need for alternative treatments. Plant-derived compounds, including alkaloids, phenylpropanoids, and terpenoids, have demonstrated anti-inflammatory effects in both preclinical and clinical studies. By modulating immune responses and promoting neuroregeneration, these compounds offer potential as novel adjunctive therapies for MS. This review provides insights into the molecular and cellular basis of MS pathogenesis, emphasizing the role of inflammation in disease progression. It critically evaluates emerging evidence supporting the use of plant-derived compounds to attenuate inflammation and MS symptomology. In addition, we provide a comprehensive source of information detailing the known mechanisms of action and assessing the clinical potential of plant-derived compounds in the context of MS pathogenesis, with a focus on their anti-inflammatory and neuroprotective properties.

Curcumin as a potential therapeutic agent for treating neurodegenerative diseases

Neurodegenerative diseases are characterized by the progressive loss of neuronal structure and function, posing a tremendous burden on health systems worldwide. Although the underlying pathological mechanisms for various neurodegenerative diseases are still unclear, a common pathological hallmark is the abundance of neuroinflammatory processes, which affect both disease onset and progression. In this review, we explore the pathways and role of neuroinflammation in various neurodegenerative diseases and further assess the potential use of curcumin, a natural spice with antioxidant and anti-inflammatory properties that has been extensively used worldwide as a traditional medicine and potential therapeutic agent. Following the examination of preclinical and clinical studies that assessed curcumin as a potential therapeutic agent, we highlight the bioavailability of curcumin in the body and discuss both the challenges and benefits of using curcumin as a therapeutic compound for treating neurodegeneration. Although elucidating the involvement of curcumin in aging and neurodegeneration has great potential for developing future CNS-related therapeutic targets, further research is required to elucidate the mechanisms by which Curcumin affects brain physiology, especially BBB integrity, under both physiological and disease conditions.

Role of Inflammation and the NF-κB Signaling Pathway in Hirschsprung's Disease

Hirschsprung's disease (HSCR, incidence 1/5000 live births) is caused by the failure of neural crest-derived precursors to migrate, survive, proliferate, or differentiate during the embryonic development of the Enteric Nervous System (ENS), which could be disrupted by many factors, including inflammatory processes. The NF-κB family controls several biological processes, including inflammation, neurogenesis, and cell migration. With the aim of studying the potential role of NF-κB in HSCR, we have analyzed the expression of the NF-κB main subunits and other NF-κB-related genes by RT-qPCR in HSCR tissue samples (sub-divided into ganglionic and aganglionic segments). We found decreased gene expression of the NF-κB main subunit RELA but also of NFKBIA, TNFA, TFGBR2, and ERBB3 in the pathologic distal aganglionic segments compared to the proximal ganglionic segments. Moreover, we could also confirm the lower protein expression of RelA/p65 in the aganglionic distal segments by immunofluorescence staining. Further, we show that the expression of RelA/p65 protein in the proximal segments concurs with lymphocyte infiltration in the bowel tissue, indicating a pro-inflammatory activation of p65 in the proximal ganglionic HSCR tissue in the patients analyzed. All in all, our findings suggest that the modulation of NF-κB signaling in the neuro-enteric system does obviously contribute to the pathological effects of HSCR.

Unraveling the interplay of neuroinflammatory signaling between parenchymal and meningeal cells in migraine headache

BACKGROUND

The initiation of migraine headaches and the involvement of neuroinflammatory signaling between parenchymal and meningeal cells remain unclear. Experimental evidence suggests that a cascade of inflammatory signaling originating from neurons may extend to the meninges, thereby inducing neurogenic inflammation and headache. This review explores the role of parenchymal inflammatory signaling in migraine headaches, drawing upon recent advancements. BODY: Studies in rodents have demonstrated that sterile meningeal inflammation can stimulate and sensitize meningeal nociceptors, culminating in headaches. The efficacy of relatively blood-brain barrier-impermeable anti-calcitonin gene-related peptide antibodies and triptans in treating migraine attacks, both with and without aura, supports the concept of migraine pain originating in meninges. Additionally, PET studies utilizing inflammation markers have revealed meningeal inflammatory activity in patients experiencing migraine with aura, particularly over the occipital cortex generating visual auras. The parenchymal neuroinflammatory signaling involving neurons, astrocytes, and microglia, which eventually extends to the meninges, can link non-homeostatic perturbations in the insensate brain to pain-sensitive meninges. Recent experimental research has brought deeper insight into parenchymal signaling mechanisms: Neuronal pannexin-1 channels act as stress sensors, initiating the inflammatory signaling by inflammasome formation and high-mobility group box-1 release in response to transient perturbations such as cortical spreading depolarization (CSD) or synaptic metabolic insufficiency caused by transcriptional changes induced by migraine triggers like sleep deprivation and stress. After a single CSD, astrocytes respond by upregulating the transcription of proinflammatory enzymes and mediators, while microglia are involved in restoring neuronal structural integrity; however, repeated CSDs may prompt microglia to adopt a pro-inflammatory state. Transcriptional changes from pro- to anti-inflammatory within 24 h may serve to dampen the inflammatory signaling. The extensive coverage of brain surface and perivascular areas by astrocyte endfeet suggests their role as an interface for transporting inflammatory mediators to the cerebrospinal fluid to contribute to meningeal nociception.

CONCLUSION

We propose that neuronal stress induced by CSD or synaptic activity-energy mismatch may initiate a parenchymal inflammatory signaling cascade, transmitted to the meninges, thereby triggering lasting headaches characteristic of migraine, with or without aura. This neuroinflammatory interplay between parenchymal and meningeal cells points to the potential for novel targets for migraine treatment and prophylaxis.

Differential effect of an evolving amyloid and tau pathology on brain phospholipids and bioactive lipid mediators in rat models of Alzheimer-like pathology

BACKGROUND

Brain inflammation contributes significantly to the pathophysiology of Alzheimer's disease, and it is manifested by glial cell activation, increased production of cytokines/chemokines, and a shift in lipid mediators from a pro-homeostatic to a pro-inflammatory profile. However, whether the production of bioactive lipid mediators is affected at earlier stages, prior to the deposition of Aβ plaques and tau hyperphosphorylation, is unknown. The differential contribution of an evolving amyloid and tau pathology on the composition and abundance of membrane phospholipids and bioactive lipid mediators also remains unresolved.

METHODS

In this study, we examined the cortical levels of DHA- and AA-derived bioactive lipid mediators and of membrane phospholipids by liquid chromatography with tandem mass spectrometry in transgenic rat models of the Alzheimer's-like amyloid and tau pathologies at early and advanced pathological stages.

RESULTS

Our findings revealed a complex balance between pro-inflammatory and pro-resolving processes in which tau pathology has a more pronounced effect compared to amyloid pathology. At stages preceding tau misfolding and aggregation, there was an increase in pro-resolving lipid mediators (RVD6 and NPD1), DHA-containing phospholipids and IFN-γ levels. However, in advanced tau pathology displaying NFT-like inclusions, neuronal death, glial activation and cognitive deficits, there was an increase in cytokine and PGD2, PGE2, and PGF2α generation accompanied by a drop in IFN-γ levels. This pathology also resulted in a marked increase in AA-containing phospholipids. In comparison, pre-plaque amyloid pathology already presented high levels of cytokines and AA-containing phospholipids together with elevated RVD6 and NPD1 levels. Finally, Aβ plaque deposition was accompanied by a modest increase in prostaglandins, increased AA-containing phospholipids and reduced DHA-containing phospholipids.

CONCLUSIONS

Our findings suggest a dynamic trajectory of inflammatory and lipid mediators in the evolving amyloid and tau pathologies and support their differing roles on membrane properties and, consequentially, on signal transduction.

Anti-Neuroinflammatory Effects of Ginkgo biloba Extract EGb 761 in LPS-Activated BV2 Microglial Cells

Inflammatory processes in the brain can exert important neuroprotective functions. However, in neurological and psychiatric disorders, it is often detrimental due to chronic microglial over-activation and the dysregulation of cytokines and chemokines. Growing evidence indicates the emerging yet prominent pathophysiological role of neuroinflammation in the development and progression of these disorders. Despite recent advances, there is still a pressing need for effective therapies, and targeting neuroinflammation is a promising approach. Therefore, in this study, we investigated the anti-neuroinflammatory potential of a marketed and quantified proprietary herbal extract of Ginkgo biloba leaves called EGb 761 (10-500 µg/mL) in BV2 microglial cells stimulated by LPS (10 ng/mL). Our results demonstrate significant inhibition of LPS-induced expression and release of cytokines tumor necrosis factor-α (TNF-α) and Interleukin 6 (IL-6) and chemokines C-X-C motif chemokine ligand 2 (CXCL2), CXCL10, c-c motif chemokine ligand 2 (CCL2) and CCL3 in BV2 microglial cells. The observed effects are possibly mediated by the mitogen-activated protein kinases (MAPK), p38 MAPK and ERK1/2, as well as the protein kinase C (PKC) and the nuclear factor (NF)-κB signaling cascades. The findings of this in vitro study highlight the anti-inflammatory properties of EGb 761 and its therapeutic potential, making it an emerging candidate for the treatment of neuroinflammatory diseases and warranting further research in pre-clinical and clinical settings.

Genus Sambucus: Exploring Its Potential as a Functional Food Ingredient with Neuroprotective Properties Mediated by Antioxidant and Anti-Inflammatory Mechanisms

The genus Sambucus, mainly Sambucus nigra, has emerged as a valuable source of bioactive compounds with potential neuroprotective properties. This review explores the antioxidant, anti-inflammatory, and neuroregenerative effects of Sambucus-derived compounds and their implications for brain health and cognitive function. In vitro studies have demonstrated the ability of Sambucus extracts to mitigate oxidative stress, modulate inflammatory responses, and promote neural stem cell proliferation and differentiation. In vivo studies using animal models of neurodegenerative diseases, such as Alzheimer's and Parkinson's, have shown that Sambucus compounds can improve cognitive function, motor performance, and neuronal survival while attenuating neuroinflammation and oxidative damage. The neuroprotective effects of Sambucus are primarily attributed to its rich content of polyphenols, particularly anthocyanins, which exert their benefits through multiple mechanisms, including the modulation of signaling pathways involved in inflammation, apoptosis, mitochondrial function, and oxidative stress. Furthermore, the potential of Sambucus as a functional food ingredient is discussed, highlighting its application in various food products and the challenges associated with the stability and bioavailability of its bioactive compounds. This review provides a comprehensive overview of the current state of research on the neuroprotective potential of Sambucus and its derivatives, offering valuable insights for the development of dietary strategies to promote brain health and prevent age-related cognitive decline.