Pretreatment with Liposome-Encapsulated Shrimp Shell Extract Attenuated Neuronal Damage and Death in Aβ1-42-Induced Memory Deficits in Rats

The accumulation of amyloid-beta (Aβ) peptides is a crucial factor in the neuronal degeneration of Alzheimer's disease (AD). The current study investigated the underlying neuroprotective mechanisms of shrimp shell extract (SSE) and liposome-encapsulated SSE (SSE/L) against Aβ1-42-induced neuronal damage and death in rats. Intracerebroventricular infusion of Aβ1-42 effectively induced memory decline, as observed in a reduction of the rat's discriminating ability in the novel object recognition and novel object location tasks. Oral pretreatment with 100 mg/kg of SSE demonstrated no preventive effect on the memory decline induced by Aβ1-42 infusion. However, treatment with SSE/L 100 mg/kg BW effectively attenuated memory deficits in both behavioral assessments following two and four weeks after Aβ1-42 infusion. Moreover, SSE/L exerted neuroprotective effects by reducing lipid peroxidation and increasing Nrf2/HO-1 expression. There was a significant decrease in Iba1 and GFAP (biomarkers of microglia and astrocyte activity, respectively), as well as a decrease in the levels of NF-κB expression and the inflammatory cytokines TNF-α and IL-6 in the cortical and hippocampal tissues. Treatment with SSE/L also reduced the pro-apoptotic proteins Bax and cleaved caspase-3 while raising the anti-apoptotic protein Bcl2. In addition, the beneficial effects of SSE/L were along with the effects of a positive control commercial astaxanthin (AST). The findings of this study indicated that SSE/L provided neuroprotective effects on Aβ1-42-induced AD rats by ameliorating oxidative stress, neuroinflammation and apoptotic cell death. Therefore, SSE/L might be employed to prevent and mitigate Aβ accumulation-induced neurotoxicity in AD.

Unveiling the link between chronic pain and misuse of opioids and cannabis

Over 50 million Americans endure chronic pain where many do not receive adequate treatment and self-medicate to manage their pain by taking substances like opioids and cannabis. Research has shown high comorbidity between chronic pain and substance use disorders (SUD) and these disorders share many common neurobiological underpinnings, including hypodopaminergic transmission. Drugs commonly used for self-medication such as opioids and cannabis relieve emotional, bothersome components of pain as well as negative emotional affect that perpetuates misuse and increases the risk of progressing towards drug abuse. However, the causal effect between chronic pain and the development of SUDs has not been clearly established. In this review, we discuss evidence that affirms the proposition that chronic pain is a risk factor for the development of opioid and cannabis use disorders by outlining the clinical evidence and detailing neurobiological mechanisms that link pain and drug misuse. Central to the link between chronic pain and opioid and cannabis misuse is hypodopaminergic transmission and the modulation of dopamine signaling in the mesolimbic pathway by opioids and cannabis. Moreover, we discuss the role of kappa opioid receptor activation and neuroinflammation in the context of dopamine transmission, their contribution to opioid and cannabis withdrawal, along with potential new treatments.

Impact of high-fat diet on cognitive behavior and central and systemic inflammation with aging and sex differences in mice

Aging and age-related diseases are associated with cellular stress, metabolic imbalance, oxidative stress, and neuroinflammation, accompanied by cognitive impairment. Lifestyle factors such as diet, sleep fragmentation, and stress can potentiate damaging cellular cascades and lead to an acceleration of brain aging and cognitive impairment. High-fat diet (HFD) has been associated with obesity, metabolic disorders like diabetes, and cardiovascular disease. HFD also induces neuroinflammation, impairs learning and memory, and may increase anxiety-like behavior. Effects of a HFD may also vary between sexes. The interaction between Age- and Sex- and Diet-related changes in neuroinflammation and cognitive function is an important and poorly understood area of research. This study was designed to examine the effects of HFD on neuroinflammation, behavior, and neurodegeneration in mice in the context of aging or sex differences. In a series of studies, young (2-3 months) or old (12-13 months) C57BL/6J male mice or young male and female C57Bl/6J mice were fed either a standard diet (SD) or a HFD for 5-6 months. Behavior was assessed in Activity Chamber, Y-maze, Novel Place Recognition, Novel Object Recognition, Elevated Plus Maze, Open Field, Morris Water Maze, and Fear Conditioning. Post-mortem analyses assessed a panel of inflammatory markers in the plasma and hippocampus. Additionally, proteomic analysis of the hypothalamus, neurodegeneration, neuroinflammation in the locus coeruleus, and neuroinflammation in the hippocampus were assessed in a subset of young and aged male mice. We show that HFD increased body weight and decreased locomotor activity across groups compared to control mice fed a SD. HFD altered anxiety-related exploratory behavior. HFD impaired spatial learning and recall in young male mice and impaired recall in cued fear conditioning in young and aged male mice, with no effects on spatial learning or fear conditioning in young female mice. Effects of Age and Sex were observed on neuroinflammatory cytokines, with only limited effects of HFD. HFD had a more significant impact on systemic inflammation in plasma across age and sex. Aged male mice had induction of microglial immunoreactivity in both the locus coeruleus (LC) and hippocampus an effect that HFD exacerbated in the hippocampal CA1 region. Proteomic analysis of the hypothalamus revealed changes in pathways related to metabolism and neurodegeneration with both aging and HFD in male mice. Our findings suggest that HFD induces widespread systemic inflammation and limited neuroinflammation. In addition, HFD alters exploratory behavior in male and female mice, and impairs learning and memory in male mice. These results provide valuable insight into the impact of diet on cognition and aging pathophysiology.

L-DOPA regulates neuroinflammation and Aβ pathology through NEP and ADAM17 in a mouse model of AD

Dopamine plays important roles in cognitive function and inflammation and therefore is involved in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD). Drugs that increase or maintain dopamine levels in the brain could be a therapeutic strategy for AD. However, the effects of dopamine and its precursor levodopa (L-DOPA) on Aβ/tau pathology in vivo and the underlying molecular mechanisms have not been studied in detail. Here, we investigated whether L-DOPA treatment alters neuroinflammation, Aβ pathology, and tau phosphorylation in 5xFAD mice, a model of AD. We found that L-DOPA administration significantly reduced microgliosis and astrogliosis in 5xFAD mice. In addition, L-DOPA treatment significantly decreased Aβ plaque number by upregulating NEP and ADAM17 levels in 5xFAD mice. However, L-DOPA-treated 5xFAD mice did not exhibit changes in tau hyperphosphorylation or tau kinase levels. These data suggest that L-DOPA alleviates neuroinflammatory responses and Aβ pathology but not tau pathology in this mouse model of AD.

Voltage-gated potassium channel 1.3: A promising molecular target in multiple disease therapy

Voltage-gated potassium channel 1.3 (Kv1.3) has emerged as a pivotal player in numerous biological processes and pathological conditions, sparking considerable interest as a potential therapeutic target across various diseases. In this review, we present a comprehensive examination of Kv1.3 channels, highlighting their fundamental characteristics and recent advancements in utilizing Kv1.3 inhibitors for treating autoimmune disorders, neuroinflammation, and cancers. Notably, Kv1.3 is prominently expressed in immune cells and implicated in immune responses and inflammation associated with autoimmune diseases and chronic inflammatory conditions. Moreover, its aberrant expression in certain tumors underscores its role in cancer progression. While preclinical studies have demonstrated the efficacy of Kv1.3 inhibitors, their clinical translation remains pending. Molecular imaging techniques offer promising avenues for tracking Kv1.3 inhibitors and assessing their therapeutic efficacy, thereby facilitating their development and clinical application. Challenges and future directions in Kv1.3 inhibitor research are also discussed, emphasizing the significant potential of targeting Kv1.3 as a promising therapeutic strategy across a spectrum of diseases.

Propionic acid ameliorates cognitive function through immunomodulatory effects on Th17 cells in perioperative neurocognitive disorders

Background

Elderly patients undergoing surgery are prone to cognitive decline known as perioperative neurocognitive disorders (PND). Several studies have shown that the microglial activation and the decrease of short-chain fatty acids (SCFAs) in gut induced by surgery may be related to the pathogenesis of PND. The purpose of this study was to determine whether microglia and short-chain fatty acids were involved in cognitive dysfunction in aged rats.

Methods

Male wild-type Wistar rats aged 11-12 months were randomly divided into control group (Ctrl: Veh group), propionic acid group (Ctrl: PA group), exploratory laparotomy group (LP: Veh group) and propionic acid + exploratory laparotomy group (LP: PA group) according to whether exploratory laparotomy (LP) or PA pretreatment for 21 days was performed. The motor ability of the rats was evaluated by open field test on postoperative day 3 (POD3), and then the cognitive function was evaluated by Y-maze test and fear conditioning test. The expression of IL-1β, IL-6, RORγt and IL-17A mRNA in hippocampus was detected by RT-qPCR, the expression of IL-17A and IL-17RA in hippocampus was detected by Western blot, and the activation of microglia was detected by immunofluorescence.

Results

The PND rat model was successfully established by laparotomy. Compared with Ctrl: Veh group, the body weight of LP: Veh group decreased, the percentage of spontaneous alternations in Y maze decreased (P < 0.001), and the percentage of freezing time in contextual fear test decreased (P < 0.001). Surgery triggers neuroinflammation, manifested as the elevated levels of the inflammatory cytokines IL-1β (P < 0.001) and IL-6 (P < 0.001), the increased expression of the transcription factor RORγt (P = 0.0181, POD1; P = 0.0073, POD5)and major inflammatory cytokines IL-17A (P = 0.0215, POD1; P = 0.0071, POD5), and the increased average fluorescence intensity of Iba1 (P < 0.001, POD1; P < 0.001, POD5). After PA preconditioning, the recovery of rats in LP: PA group was faster than that in LP: Veh group as the body weight lost on POD1 (P = 0.0148) was close to the baseline level on POD5 (P = 0.1846), and they performed better in behavioral tests. The levels of IL-1β (P < 0.001) and IL-6 (P = 0.0035) inflammatory factors in hippocampus decreased on POD1 and the average fluorescence intensity of Iba1 decreased (P = 0.0024, POD1; P < 0.001, POD5), representing the neuroinflammation was significantly improved. Besides, the levels of RORγt mRNA (P = 0.0231, POD1; P = 0.0251, POD5) and IL-17A mRNA (P = 0.0208, POD1; P = 0.0071, POD5) in hippocampus as well as the expression of IL-17A (P = 0.0057, POD1; P < 0.001, POD5) and IL-17RA (P = 0.0388) decreased.

Conclusion

PA pretreatment results in reduced postoperative neuroinflammation and improved cognitive function, potentially attributed to the regulatory effects of PA on Th17-mediated immune responses.

Neuroprotective effect of tanshinone IIA-modified mesenchymal stem cells in a lipopolysaccharide-induced neuroinflammation model

In this study, the neuroprotective potential of tanshinone IIA (TIIA)-modified mesenchymal stem cells (MSC) were investigated using a murine model of lipopolysaccharide (LPS)-induced neuroinflammation. The cognitive performance of the mice was assessed using the Y-maze and Morris water maze tests, while immunofluorescence and Western blot analyses were employed to evaluate the hippocampal expression of pertinent markers and inflammatory factors, respectively. The results from the behavioral experiments demonstrated discernible differences in learning and memory abilities between the model group and the control group (P < 0.05), confirming the successful induction of neuroinflammation. Both the MSC and TIIA-MSC groups exhibited enhancements in the cognitive abilities of neuroinflammatory mice, with the TIIA-MSC group demonstrating a more pronounced improvement (P < 0.01). Immunofluorescence analysis revealed significant activation of microglia in the model group, while the MSC and TIIA-MSC groups exhibited a reduction in hippocampal microglial activation, with the TIIA-MSC group displaying a more substantial decrease. A statistically significant difference in the expression levels of IL-1, IL-6, and TNF-α was observed between the model and control groups (P < 0.05), indicating that IL-1, IL-6, and TNF-α were downregulated in both the MSC and TIIA-MSC groups. Notably, the downregulatory effect was more prominent in the TIIA-MSC group (P < 0.01). Compared to MSC treatment alone, the administration of TIIA-modified MSC demonstrated a superior protective effect against lipopolysaccharide-induced neuroinflammation. These findings underscore the potential therapeutic efficacy of TIIA-modified MSC in mitigating neuroinflammatory responses.

Bone-derived PDGF-BB enhances hippocampal non-specific transcytosis through microglia-endothelial crosstalk in HFD-induced metabolic syndrome

BACKGROUND

It is well known that high-fat diet (HFD)-induced metabolic syndrome plays a crucial role in cognitive decline and brain-blood barrier (BBB) breakdown. However, whether the bone-brain axis participates in this pathological process remains unknown. Here, we report that platelet-derived growth factor-BB (PDGF-BB) secretion by preosteoclasts in the bone accelerates neuroinflammation. The expression of alkaline phosphatase (ALPL), a nonspecific transcytosis marker, was upregulated during HFD challenge.

MAIN BODY

Preosteoclast-specific Pdgfb transgenic mice with high PDGF-BB concentrations in the circulation recapitulated the HFD-induced neuroinflammation and transcytosis shift. Preosteoclast-specific Pdgfb knockout mice were partially rescued from hippocampal neuroinflammation and transcytosis shifts in HFD-challenged mice. HFD-induced PDGF-BB elevation aggravated microglia-associated neuroinflammation and interleukin-1β (IL-1β) secretion, which increased ALPL expression and transcytosis shift through enhancing protein 1 (SP1) translocation in endothelial cells.

CONCLUSION

Our findings confirm the role of bone-secreted PDGF-BB in neuroinflammation and the transcytosis shift in the hippocampal region during HFD challenge and identify a novel mechanism of microglia-endothelial crosstalk in HFD-induced metabolic syndrome.

Long-Term Accumulation of T Cytotoxic 1, T Cytotoxic 17, and T Cytotoxic 17/1 Cells in the Brain Contributes to Microglia-Mediated Chronic Neuroinflammation After Ischemic Stroke

Post-stroke neuroinflammation affects the damage and recovery of neurological functions. T cells including CD8+ T cells were present in the ipsilateral hemisphere in the subacute and late phases of ischemic stroke. However, the potential roles of CD8+ T cell subsets in the progression of neuroinflammation have not been characterized. In the current mouse transient middle cerebral artery occlusion model, we investigated the existence of CD8+ T cell subsets in the ipsilateral hemisphere in the subacute and late phases of stroke. We found that ipsilateral CD8+ T cells were present on post-stroke day 3 and increased on post-stroke day 30. The day-3 ipsilateral CD8+ T cells predominantly produced interferon-γ (IFN-γ), while the day-30 ipsilateral CD8+ T cells co-expressed IFN-γ and interleukin-17A (IL-17A). In addition, evaluation of cytokines and transcription factors of the day-30 ipsilateral CD8+ T cells revealed the presence of T cytotoxic 1 (Tc1), T cytotoxic 17 (Tc17), and T cytotoxic 17/1 (Tc17/1) cells. Furthermore, based on the expression of a series of chemokine/cytokine receptors, viable ipsilateral Tc1, Tc17, and Tc17.1 cells were identified and enriched from the day-30 ipsilateral CD8+ T cells, respectively. Co-culture of microglia with ipsilateral Tc1, Tc17, or Tc17.1 cells indicated that the three CD8+ T cell subsets up-regulated the expression of pro-inflammatory mediators by microglia, with Tc17.1 cells being the most potent cell in doing so. Collectively, this study sheds light on the contributions of Tc1, Tc17, and Tc17.1 cells to long-term neuroinflammation after ischemic stroke.

Interaction of high-fat diet and brain trauma alters adipose tissue macrophages and brain microglia associated with exacerbated cognitive dysfunction

Obesity increases the morbidity and mortality of traumatic brain injury (TBI). Detailed analyses of transcriptomic changes in the brain and adipose tissue were performed to elucidate the interactive effects between high-fat diet-induced obesity (DIO) and TBI. Adult male mice were fed a high-fat diet (HFD) for 12 weeks prior to experimental TBI and continuing after injury. High-throughput transcriptomic analysis using Nanostring panels of the total visceral adipose tissue (VAT) and cellular components in the brain, followed by unsupervised clustering, principal component analysis, and IPA pathway analysis were used to determine shifts in gene expression patterns and molecular pathway activity. Cellular populations in the cortex and hippocampus, as well as in VAT, during the chronic phase after combined TBI-HFD showed amplification of central and peripheral microglia/macrophage responses, including superadditive changes in selected gene expression signatures and pathways. Furthermore, combined TBI and HFD caused additive dysfunction in Y-Maze, Novel Object Recognition (NOR), and Morris water maze (MWM) cognitive function tests. These novel data suggest that HFD-induced obesity and TBI can independently prime and support the development of altered states in brain microglia and VAT, including the disease-associated microglia/macrophage (DAM) phenotype observed in neurodegenerative disorders. The interaction between HFD and TBI promotes a shift toward chronic reactive microglia/macrophage transcriptomic signatures and associated pro-inflammatory disease-altered states that may, in part, underlie the exacerbation of cognitive deficits. Thus, targeting of HFD-induced reactive cellular phenotypes, including in peripheral adipose tissue immune cell populations, may serve to reduce microglial maladaptive states after TBI, attenuating post-traumatic neurodegeneration and neurological dysfunction.

Increased levels and activation of the IL-17 receptor in microglia contribute to enhanced neuroinflammation in cerebellum of hyperammonemic rats

BACKGROUND

Patients with liver cirrhosis may show minimal hepatic encephalopathy (MHE) with mild cognitive impairment and motor incoordination. Rats with chronic hyperammonemia reproduce these alterations. Motor incoordination in hyperammonemic rats is due to increased GABAergic neurotransmission in cerebellum, induced by neuroinflammation, which enhances TNFα-TNFR1-S1PR2-CCL2-BDNF-TrkB pathway activation. The initial events by which hyperammonemia triggers activation of this pathway remain unclear. MHE in cirrhotic patients is triggered by a shift in inflammation with increased IL-17. The aims of this work were: (1) assess if hyperammonemia increases IL-17 content and membrane expression of its receptor in cerebellum of hyperammonemic rats; (2) identify the cell types in which IL-17 receptor is expressed and IL-17 increases in hyperammonemia; (3) assess if blocking IL-17 signaling with anti-IL-17 ex-vivo reverses activation of glia and of the TNFα-TNFR1-S1PR2-CCL2-BDNF-TrkB pathway.

RESULTS

IL-17 levels and membrane expression of the IL-17 receptor are increased in cerebellum of rats with hyperammonemia and MHE, leading to increased activation of IL-17 receptor in microglia, which triggers activation of STAT3 and NF-kB, increasing IL-17 and TNFα levels, respectively. TNFα released from microglia activates TNFR1 in Purkinje neurons, leading to activation of NF-kB and increased IL-17 and TNFα also in these cells. Enhanced TNFR1 activation also enhances activation of the TNFR1-S1PR2-CCL2-BDNF-TrkB pathway which mediates microglia and astrocytes activation.

CONCLUSIONS

All these steps are triggered by enhanced activation of IL-17 receptor in microglia and are prevented by ex-vivo treatment with anti-IL-17. IL-17 and IL-17 receptor in microglia would be therapeutic targets to treat neurological impairment in patients with MHE.

Edaravone Dexborneol mitigates pathology in animal and cell culture models of Alzheimer's disease by inhibiting neuroinflammation and neuronal necroptosis

BACKGROUND

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease with limited disease-modifying treatments. Drug repositioning strategy has now emerged as a promising approach for anti-AD drug discovery. Using 5×FAD mice and Aβ-treated neurons in culture, we tested the efficacy of Y-2, a compounded drug containing the antioxidant Edaravone (Eda), a pyrazolone and (+)-Borneol, an anti-inflammatory diterpenoid from cinnamon, approved for use in amyotrophic lateral sclerosis patients.

RESULTS

We examined effects of Y-2 versus Eda alone by i.p. administered in 8-week-old 5×FAD mice (females) for 4 months by comparing cognitive function, Aβ pathologies, neuronal necroptosis and neuroinflammation. Using primary neurons and astrocytes, as well as neuronal and astrocytic cell lines, we elucidated the molecular mechanisms of Y-2 by examining neuronal injury, astrocyte-mediated inflammation and necroptosis. Here, we find that Y-2 improves cognitive function in AD mice. Histopathological data show that Y-2, better than Eda alone, markedly ameliorates Aβ pathologies including Aβ burden, astrogliosis/microgliosis, and Tau phosphorylation. In addition, Y-2 reduces Aβ-induced neuronal injury including neurite damage, mitochondrial impairment, reactive oxygen species production and NAD+ depletion. Notably, Y-2 inhibits astrocyte-mediated neuroinflammation and attenuates TNF-α-triggered neuronal necroptosis in cell cultures and AD mice. RNA-seq further demonstrates that Y-2, compared to Eda, indeed upregulates anti-inflammation pathways in astrocytes.

CONCLUSIONS

Our findings infer that Y-2, better than Eda alone, mitigates AD pathology and may provide a potential drug candidate for AD treatment.

Cyclooxygenase-2 inhibitors alleviated depressive and anxious-like behaviors in mice exposed to lipopolysaccharide: Involvement of oxidative stress and neuroinflammation

Depression and anxiety disorders have their pathophysiologies linked to inflammation and oxidative stress. In this context, celecoxib (CLX) and etoricoxib (ETR) inhibit cyclooxygenase 2 (COX-2), an enzyme expressed by cells involved in the inflammatory process and found in the brain. Studies have been using CLX as a possible drug in the treatment of depression, although its mechanisms at the central nervous system level are not fully elucidated. In this study, the effects of CLX and ETR on behavioral, oxidative, and inflammatory changes induced by systemic exposure to Escherichia coli lipopolysaccharide (LPS) were evaluated in adult male swiss mice. For ten days, the animals received intraperitoneal injections of LPS at 0.5 mg/kg. From the sixth to the tenth day, one hour after LPS exposure, they were treated orally with CLX (15 mg/kg), ETR (10 mg/kg), or fluoxetine (FLU) (20 mg/kg). Twenty-four hours after the last oral administration, the animals underwent evaluation of locomotor activity (open field test), predictive tests for depressive-like behavior (forced swim and tail suspension tests), and anxiolytic-like effect (elevated plus maze and hole board tests). Subsequently, the hippocampus, prefrontal cortex and striatum were dissected for the measurement of oxidative and nitrosative parameters (malondialdehyde, nitrite, and glutathione) and quantification of pro-inflammatory cytokines (IL-1β and IL-6). LPS induced depressive and anxious-like behavior, and treatment with CLX or ETR was able to reverse most of the behavioral changes. It was evidenced that nitrosative stress and the degree of lipid peroxidation induced by LPS were reduced in different brain areas after treatment with the drugs, as well as the endogenous defense system against free radicals was strengthened. CLX and ETR also significantly reduced LPS-induced cytokine levels. These data are expected to expand information on the role of inflammation in depression and anxiety and provide insights into possible mechanisms of COX-2 inhibitors in psychiatric disorders with a neurobiological basis in inflammation and oxidative stress.

Obesity-induced blood-brain barrier dysfunction: phenotypes and mechanisms

Obesity, a burgeoning global health issue, is increasingly recognized for its detrimental effects on the central nervous system, particularly concerning the integrity of the blood-brain barrier (BBB). This manuscript delves into the intricate relationship between obesity and BBB dysfunction, elucidating the underlying phenotypes and molecular mechanisms. We commence with an overview of the BBB's critical role in maintaining cerebral homeostasis and the pathological alterations induced by obesity. By employing a comprehensive literature review, we examine the structural and functional modifications of the BBB in the context of obesity, including increased permeability, altered transport mechanisms, and inflammatory responses. The manuscript highlights how obesity-induced systemic inflammation and metabolic dysregulation contribute to BBB disruption, thereby predisposing individuals to various neurological disorders. We further explore the potential pathways, such as oxidative stress and endothelial cell dysfunction, that mediate these changes. Our discussion culminates in the summary of current findings and the identification of knowledge gaps, paving the way for future research directions. This review underscores the significance of understanding BBB dysfunction in obesity, not only for its implications in neurodegenerative diseases but also for developing targeted therapeutic strategies to mitigate these effects.

Dantrolene alleviates mitochondrial dysfunction and neuroinflammation in traumatic brain injury by modulating the NF-ĸβ/Akt pathway

Traumatic brain injury (TBI) triggers a bevy of changes including mitochondrial dysfunction, apoptosis, oxidative stress, neurobehavioural impairment, and neuroinflammation, among others. Dantrolene (DNT), a muscle relaxant which inhibits intracellular Ca2+ signaling from the ER, has been repurposed as a potential neuroprotective agent in various neurological diseases. However, there have been limited studies on whether it can mitigate TBI-induced deficits and restore impaired mitochondrial dynamics. This study sought to evaluate whether Dantrolene can potentially provide neuroprotection in an in vivo model of TBI. Male wistar rats subjected to TBI were treated with DNT (10 mg/kg) 1 h and 12 h post surgery. Animals were assessed 24 h post-TBI to evaluate neurobehavioural deficits and cerebral edema. We evaluated the protein expressions of apoptotic, autophagic, and neuroinflammatory markers by immunoblotting, as well as Mitochondrial Membrane Potential (MMP) and Reactive Oxygen Species (ROS) via Flow Cytometry to ascertain the effects of DNT on TBI. We further analysed immunofluorescence staining with Glial Fibrillary Acidic Protein (GFAP) and immunohistochemistry with NF-κβ to investigate neuroinflammation. H&E staining was also performed post-TBI. Our findings revealed DNT administration inhibits mitochondria-mediated apoptotis and reduces heightened oxidative stress. DNT treatment was also found to reverse neurobehavioural impairments and offer neuroprotection by preserving neuronal architechture. We also demonstrated that DNT inhibits neuronal autophagy and alleviates neuroinflammation following TBI by modulating the NF-κβ/Akt signaling pathway. Thus, our results suggest a novel application of DNT in ameliorating the multitude of deficits induced by TBI, thereby conferring neuroprotection.

A novel p55PIK signaling peptide inhibitor alleviates neuroinflammation via the STAT3/NF-kB signaling pathway in experimental stroke

BACKGROUND

Ischemic stroke remains the predominant contributor to mortality and disability globally. Microglia undergo rapid activation and initiate inflammatory cascade reactions by phenotypic polarization, participating in the regulation of inflammatory injury and tissue repair post-ischemic stroke. Regulating microglia-mediated neuroinflammation is a promising therapeutic strategy for ischemic stroke. Previously, we designed and synthesized a novel p55PIK inhibitor, TAT-N15 polypeptide, which presents inhibitive activity on NF-κB signaling-mediated inflammation in acute conjunctivitis and allergic rhinitis. The present study aimed to explore the therapeutic effect and mechanism of TAT-N15 on ischemia stroke.

METHODS

The mouse model of transient cerebral ischemia was made using the intraluminal filament method. After being treated with daily intraperitoneal injections of TAT-N15 (10 mg/kg) for 7 d, the neurological outcomes and the cerebral infarction volume were evaluated. Histopathology of the ischemia cerebral hemisphere was observed by H&E and Nissl staining. Neuronal survival, astrogliosis, and co-labeling of CD86/Iba1 and CD206/Iba1 were detected by immunofluorescence. The cell apoptosis was estimated by TUNEL staining. The expression levels of apoptosis-associated proteins, proinflammatory cytokines, protein markers of M1 and M2 microglia, and the phosphorylation of NF-κB and STAT3 proteins in the ischemic penumbra were detected by Western blot.

RESULTS

TAT-N15 treatment significantly decreased the infarct volume and alleviated neurological functional impairment, neuronal injury, and neuron apoptosis. Meanwhile, TAT-N15 treatment restrained the activation of microglia and astrocytes as well as the protein expression of proinflammatory cytokine in ischemic penumbra. Additionally, the administration of TAT-N15 treatment resulted in a significant reduction in the density of M1 phenotype microglia while concurrently increasing the density of M2 phenotype microglia within the ischemic penumbra. Finally, mechanical analysis unveiled that TAT-N15 exerted a substantial inhibitory effect on the protein expression of phosphorylated STAT3 and NF-κB.

CONCLUSION

TAT-N15 may inhibit neuroinflammation via regulating microglia activation and polarization through the STAT3/NF-κB pathway, which exhibits the neuroprotection effect in ischemic stroke.

Evaluating the utility of serum NfL, GFAP, UCHL1 and tTAU as estimates of CSF levels and diagnostic instrument in neuroinflammation and multiple sclerosis

BACKGROUND

This study aimed to evaluate the utility of neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase L1 (UCHL1) and total tau (tTAU) serum concentrations as approximation for cerebrospinal fluid (CSF) concentrations of the respective biomarkers in the context of neuroinflammation and multiple sclerosis (MS).

METHODS

NfL, GFAP, UCHL1 and tTAU concentrations in serum and CSF were measured in 183 patients (122 with neuroinflammatory disease and 61 neurological or somatoform disease controls) using the single molecule array HD-1 analyzer (Quanterix, Boston, MA). Spearman's rank correlations were computed between serum and CSF concentrations. In a second step, the effects of age, BMI, gadolinium-enhancing lesions in MRI, integrity of the blood-brain barrier (BBB) and presence of acute relapse were accounted for by computing partial correlations. The analyses were repeated for a subsample consisting of MS phenotype patients only (n = 118). EDSS, MS disease activity and acute relapse were considered as additional covariates. Receiver operating characteristic (ROC) analysis was performed for each serum/CSF biomarker concentration to assess how well the particular biomarker concentration differentiates MS patients from somatoform disease controls. Correlations between serum and CSF levels as well as area under the curve (AUC) values were compared for the different biomarkers using z-test statistics.

RESULTS

Serum concentrations correlated positively with CSF levels for NfL (r = 0.705, p < 0.01) as well as for GFAP (r = 0.259, p < 0.01). Correlation coefficients were significantly higher for NfL than for GFAP (z = 5.492, p < 0.01). We found no significant serum-CSF correlations for UCHL1 or tTAU. After adjusting for covariates, the results remained unchanged. In the analysis focusing only on MS patients, the results were replicated. ROC analysis demonstrated similarly acceptable performance of serum and CSF NfL values in differentiating MS phenotype patients from somatoform disease controls. AUC values were significantly higher for serum and CSF NfL compared to other biomarkers.

CONCLUSION

NfL and GFAP but not UCHL1 or tTAU serum concentrations are associated with CSF levels of the respective biomarker. NfL exhibits more robust correlations between its serum and CSF concentrations as compared to GFAP independently from BBB integrity, clinical and radiological covariates. Both serum and CSF NfL values differentiate between MS and controls.

Alpha-synuclein inclusion responsive microglia are resistant to CSF1R inhibition

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disorder that is characterized by the presence of proteinaceous alpha-synuclein (α-syn) inclusions (Lewy bodies), markers of neuroinflammation and the progressive loss of nigrostriatal dopamine (DA) neurons. These pathological features can be recapitulated in vivo using the α-syn preformed fibril (PFF) model of synucleinopathy. We have previously determined that microglia proximal to PFF-induced nigral α-syn inclusions increase in soma size, upregulate major-histocompatibility complex-II (MHC-II) expression, and increase expression of a suite of inflammation-associated transcripts. This microglial response is observed months prior to degeneration, suggesting that microglia reacting to α-syn inclusion may contribute to neurodegeneration and could represent a potential target for novel therapeutics. The goal of this study was to determine whether colony stimulating factor-1 receptor (CSF1R)-mediated microglial depletion impacts the magnitude of α-syn aggregation, nigrostriatal degeneration, or the response of microglial in the context of the α-syn PFF model.

METHODS

Male Fischer 344 rats were injected intrastriatally with either α-syn PFFs or saline. Rats were continuously administered Pexidartinib (PLX3397B, 600 mg/kg), a CSF1R inhibitor, to deplete microglia for a period of either 2 or 6 months.

RESULTS

CSF1R inhibition resulted in significant depletion (~ 43%) of ionized calcium-binding adapter molecule 1 immunoreactive (Iba-1ir) microglia within the SNpc. However, CSF1R inhibition did not impact the increase in microglial number, soma size, number of MHC-II immunoreactive microglia or microglial expression of Cd74, Cxcl10, Rt-1a2, Grn, Csf1r, Tyrobp, and Fcer1g associated with phosphorylated α-syn (pSyn) nigral inclusions. Further, accumulation of pSyn and degeneration of nigral neurons was not impacted by CSF1R inhibition. Paradoxically, long term CSF1R inhibition resulted in increased soma size of remaining Iba-1ir microglia in both control and PFF rats, as well as expression of MHC-II in extranigral regions.

CONCLUSIONS

Collectively, our results suggest that CSF1R inhibition does not impact the microglial response to nigral pSyn inclusions and that CSF1R inhibition is not a viable disease-modifying strategy for PD.

Regulatory roles of microRNAs in modulating mitochondrial dynamics, amyloid beta fibrillation, microglial activation, and cholinergic signaling: Implications for alzheimer's disease pathogenesis

Alzheimer's Disease (AD) remains a formidable challenge due to its complex pathology, notably involving mitochondrial dysfunction and dysregulated microRNA (miRNA) signaling. This study delves into the underexplored realm of miRNAs' impact on mitochondrial dynamics and their interplay with amyloid-beta (Aβ) aggregation and tau pathology in AD. Addressing identified gaps, our research utilizes advanced molecular techniques and AD models, alongside patient miRNA profiles, to uncover miRNAs pivotal in mitochondrial regulation. We illuminate novel miRNAs influencing mitochondrial dynamics, Aβ, and tau, offering insights into their mechanistic roles in AD progression. Our findings not only enhance understanding of AD's molecular underpinnings but also spotlight miRNAs as promising therapeutic targets. By elucidating miRNAs' roles in mitochondrial dysfunction and their interactions with hallmark AD pathologies, our work proposes innovative strategies for AD therapy, aiming to mitigate disease progression through targeted miRNA modulation. This contribution marks a significant step toward novel AD treatments, emphasizing the potential of miRNAs in addressing this complex disease.

Adaptive immune changes associate with clinical progression of Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the most frequent cause of dementia. Recent evidence suggests the involvement of peripheral immune cells in the disease, but the underlying mechanisms remain unclear.

METHODS

We comprehensively mapped peripheral immune changes in AD patients with mild cognitive impairment (MCI) or dementia compared to controls, using cytometry by time-of-flight (CyTOF).

RESULTS

We found an adaptive immune signature in AD, and specifically highlight the accumulation of PD1+ CD57+ CD8+ T effector memory cells re-expressing CD45RA in the MCI stage of AD. In addition, several innate and adaptive immune cell subsets correlated to cerebrospinal fluid (CSF) biomarkers of AD neuropathology and measures for cognitive decline. Intriguingly, subsets of memory T and B cells were negatively associated with CSF biomarkers for tau pathology, neurodegeneration and neuroinflammation in AD patients. Lastly, we established the influence of the APOE ε4 allele on peripheral immunity.

CONCLUSIONS

Our findings illustrate significant peripheral immune alterations associated with both early and late clinical stages of AD, emphasizing the necessity for further investigation into how these changes influence underlying brain pathology.

Galectin-3 absence alters lymphocytes populations dynamics behavior and promotes functional recovery after spinal cord injury in mice

Spinal cord injury (SCI) results from various mechanisms that damage the nervous tissue and the blood-brain barrier, leading to sensory and motor function loss below the injury site. Unfortunately, current therapeutic approaches for SCI have limited efficacy in improving patients outcomes. Galectin-3, a protein whose expression increases after SCI, influences the neuroinflammatory response by favoring pro-inflammatory M1 macrophages and microglia, while inhibiting pro-regenerative M2 macrophages and microglia, which are crucial for inflammation resolution and tissue regeneration. Previous studies with Galectin-3 knock-out mice demonstrated enhanced motor recovery after SCI. The M1/M2 balance is strongly influenced by the predominant lymphocytic profiles (Th1, Th2, T Reg, Th17) and cytokines and chemokines released at the lesion site. The present study aimed to investigate how the absence of galectin-3 impacts the adaptive immune system cell population dynamics in various lymphoid spaces following a low thoracic spinal cord compression injury (T9-T10) using a 30 g vascular clip for one minute. It also aimed to assess its influence on the functional outcome in wild-type (WT)and Galectin-3 knock-out (GALNEG) mice. Histological analysis with hematoxylin-eosin and Luxol Fast Blue staining revealed that WT and GALNEG animals exhibit similar spinal cord morphology. The absence of galectin-3 does not affect the common neuroanatomy shared between the groups prompting us to analyze outcomes between both groups. Following our crush model, both groups lost motor and sensory functions below the lesion level. During a 42-day period, GALNEG mice demonstrated superior locomotor recovery in the Basso Mouse Scale (BMS) gait analysis and enhanced motor coordination performance in the ladder rung walk test (LRW) compared to WT mice. GALNEG mice also exhibited better sensory recovery, and their electrophysiological parameters suggested a higher number of functional axons with faster nerve conduction. Seven days after injury, flow cytometry of thymus, spleen, and blood revealed an increased number of T Reg and Th2 cells, accompanied by a decrease in Th1 and Th17 cells in GALNEG mice. Immunohistochemistry conducted on the same day exhibited an increased number of Th2 and T Reg cells around the GALNEG's spinal cord lesion site. At 42-day dpi immunohistochemistry analyses displayed reduced astrogliosis and greater axon preservation in GALNEG's spinal cord seem as a reduction of GFAP immunostaining and an increase in NFH immunostaining, respectively. In conclusion, GALNEG mice exhibited better functional recovery attributed to the milder pro-inflammatory influence, compensated by a higher quantity of T Reg and Th2 cells. These findings suggest that galectin-3 plays a crucial role in the immune response after spinal cord injury and could be a potential target for clinical therapeutic interventions.

Potential therapeutic and diagnostic approaches of exosomes in multiple sclerosis pathophysiology

Exosomes are bilayer lipid vesicles that are released by cells and contain proteins, nucleic acids, and lipids. They can be internalized by other cells, inducing inflammatory responses and instigating toxicities in the recipient cells. Exosomes can also serve as therapeutic vehicles by transporting protective cargo to maintain homeostasis. Multiple studies have shown that exosomes can initiate and participate in the regulation of neuroinflammation, improve neurogenesis, and are closely related to the pathogenesis of central nervous system (CNS) diseases, including multiple sclerosis (MS). Exosomes can be secreted by both neurons and glial cells in the CNS, and their contents change with disease occurrence. Due to their ability to penetrate the blood-brain barrier and their stability in peripheral fluids, exosomes are attractive biomarkers of CNS diseases. In recent years, exosomes have emerged as potential therapeutic agents for CNS diseases, including MS. However, the molecular pathways in the pathogenesis of MS are still unknown, and further research is needed to fully understand the role of exosomes in the occurrence or improvement of MS disease. Thereby, in this review, we intend to provide a more complete understanding of the pathways in which exosomes are involved and affect the occurrence or improvement of MS disease.

Microglial Exosomes in Paraquat-Induced Parkinson's Disease: Neuroprotection and Biomarker Clues

The exact mechanisms underlying the initiation and exacerbation of Parkinson's disease (PD) by paraquat remain unclear. We have revealed that exosomes mediate neurotoxicity induced by low dose paraquat exposure by transmitting intercellular signaling. Exposure to 40 μM paraquat promoted exosome release from mouse microglia cells (BV2) in vitro. Paraquat exposure at 100 μM caused degeneration of mouse dopaminergic MN9D cells and inhibited microglia exosome uptake by fluorescently labeling exosomes. We established an incubation model for exosomes and dopaminergic neuron cells under PQ treatment. The results indicated that microglial exosomes alleviated degeneration, increasing proliferation and PD-related protein expression of dopaminergic neurons; however, paraquat reversed this effect. Then, through exosome high-throughput sequencing and qRT-PCR experiments, miR-92a-3p and miR-24-3p were observed to transfer from exosomes to dopaminergic neurons, inhibited by paraquat. The specificity of miR-92a-3p and miR-24-3p was verified in PD patients exosomes, indicating the potential diagnostic value of the exosomal miRNAs in paraquat-induced PD. These results suggest glia-neuron communication in paraquat-induced neurodegeneration and may identify stable paraquat-mediated PD biomarkers, offering clues for early recognition and prevention of pesticide-induced degenerative diseases.

Fatsia japonica extract exerts antioxidant and anti-neuroinflammatory effects on neuronal cells and a zebrafish model

ETHNOPHARMACOLOGICAL RELEVANCE

Fatsia japonica is a traditional medicine used to treat various diseases, including inflammation-related disorders. However, its antineuroinflammatory and neuroprotective effects remain unclear.

AIM OF THE STUDY

We aimed to evaluate the anti-neuroinflammatory and neuroprotective effects of F. japonica extract to identify the underlying mechanisms.

MATERIALS AND METHODS

The components of F. japonica extract were profiled using ultra-high-performance liquid chromatography-mass spectrometry. The effects of F. japonica extract were investigated in BV2 microglia and HT22 hippocampal cells. Furthermore, in vivo effects of F. japonica extract were assessed using zebrafish models treated with H2O2 and LPS to evaluate the effects of in vivo.

RESULTS

We identified 27 compounds in the F. japonica extract. F. japonica extract demonstrated anti-inflammatory properties by suppressing LPS-induced inflammatory responses in both BV2 cells and zebrafish, along with inhibiting the activation of the nuclear factor (NF)-κB (p65) pathway. The protective effects of this extract were also observed on glutamate-treated HT22 cells and in H2O2-induced zebrafish. Furthermore, F. japonica extract upregulated nuclear factor E2-related (Nrf) 2/heme oxygenase (HO)-1 expression in BV2 and HT22 cells.

CONCLUSIONS

F. japonica extract exerted anti-neuroinflammatory and neuroprotective effects through Nrf2/HO-1 and the NF-κB pathway.

Cell-Free Supernatant of Lactobacillus rhamnosus and Bifidobacterium breve Ameliorates Ischemic Stroke-Generated Neurological Deficits in Rats

The beneficial effects of probiotics, postbiotics, and paraprobiotics have already been registered in managing ischemic stroke-generated neuroinflammation and gut dysbiosis. Herein, we examined the impact of cell-free supernatant (CFS) obtained from probiotics (Lactobacillus rhamnosus UBLR-58 and Bifidobacterium breve UBBr-01) in a rat transient middle cerebral artery occlusion (MCAO) model of focal cerebral injury. Pre-MCAO supplementation of probiotics (2 × 109 CFU/mL) for 21 days or CFS (1 mL/rat) for 7 days protect the MCAO-induced somatosensory and motor impairments recorded at 24 h and 72 h after reperfusion in foot-fault, rotarod, adhesive removal, and vibrissae-evoked forelimb placing tests. We also noted the reduced infarct area and neuronal degradation in the right hemisphere of probiotics- and CFS-recipient MCAO-operated animals. Moreover, MCAO-induced altered concentrations of glial-fibrillary acidic protein, NeuN, zonula occludens-1 (ZO-1), TLR4, IL-1β, IL-6, and TNF-α, as well as matrix metalloproteinase-9 (MMP9) were reversed in the treatment groups. Probiotics and CFS treatment ameliorated the elevated levels of IL-6, IL-1β, and MMP9 in the blood plasma of rats. The disrupted microbial phyla, Firmicutes-to-Bacteroides ratio, villi/crypt ratio, and decreased mucin-producing goblet cells, ZO-1, and occludin in the colon of MCAO-operated rats were recovered following probiotics and CFS treatment. NMR characterization of CFS and rat blood plasma revealed the presence of several important bacterial metabolites. These findings suggest that the CFS obtained from Lactobacillus rhamnosus UBLR-58 and Bifidobacterium breve UBBr-01 has the propensity to improve MCAO-generated neurological dysfunctions in rats by dampening neuroinflammation and modulating the gut-brain axis modulators.

Arjunolic acid ameliorates lipopolysaccharide-induced depressive behavior by inhibiting neuroinflammation via microglial SIRT1/AMPK/Notch1 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Neuroinflammation is involved in the pathogenesis of depression disorder by activating microglia cells, increasing proinflammatory cytokines, effecting serotonin synthesis and metabolism, and neuronal apoptosis and neurogenesis. Arjunolic acid (ARG) is a triterpenoid derived from the fruits of Akebia trifoliata for treating psychiatric disorders in TCM clinic, which exhibits anti-inflammatory and neuroprotective effects. However, its anti-depressive effect and underlying mechanism are unknown.

AIM OF THE STUDY

The aim of this study is to explore the effect of arjunolic acid on depression and its possible mechanisms.

METHODS

Intraperitoneal injection of LPS in mice and LPS stimulated-BV2 microglia were utilized to set up in vivo and in vitro models. Behavioral tests, H&E staining and ELISA were employed to evaluate the effect of arjunolic acid on depression. RT-qPCR, immunofluorescence, molecular docking and Western blot were performed to elucidate the molecular mechanisms.

RESULTS

Arjunolic acid dramatically ameliorated depressive behavior in LPS-induced mice. The levels of BDNF and 5-HT in the hippocampus of the mice were increased, while the number of iNOS + IBA1+ cells in the brain were decreased and Arg1+IBA1+ positive cells were increased after arjunolic acid treatment. In addition, arjunolic acid promoted the polarization of BV2 microglia from M1 to M2 type. Notably, drug affinity responsive target stability (DARTS), cellular thermal shift assay (CETSA) and molecular docking technologies identified SIRT1 as the target of arjunolic acid. Moreover, after SIRT1 inhibition by using EX-527, the effects of arjunolic acid on ameliorating LPS-induced depressive behavior in mice and promoting M2 Microglia polarization were blocked. In addition, arjunolic acid activated AMPK and decreased Notch1 expression, however, inhibition of AMPK, the effect of arjunolic acid on the downregulation of Notch1 expression were weaken.

CONCLUSIONS

This study elucidates that arjunolic acid suppressed neuroinflammation through modulating the SIRT1/AMPK/Notch1 signaling pathway. Our study demonstrates that arjunolic acid might serve as a potiential anti-depressant.

Regulation of human microglial gene expression and function via RNAase-H active antisense oligonucleotides in vivo in Alzheimer's disease

BACKGROUND

Microglia play important roles in maintaining brain homeostasis and neurodegeneration. The discovery of genetic variants in genes predominately or exclusively expressed in myeloid cells, such as Apolipoprotein E (APOE) and triggering receptor expressed on myeloid cells 2 (TREM2), as the strongest risk factors for Alzheimer's disease (AD) highlights the importance of microglial biology in the brain. The sequence, structure and function of several microglial proteins are poorly conserved across species, which has hampered the development of strategies aiming to modulate the expression of specific microglial genes. One way to target APOE and TREM2 is to modulate their expression using antisense oligonucleotides (ASOs).

METHODS

In this study, we identified, produced, and tested novel, selective and potent ASOs for human APOE and TREM2. We used a combination of in vitro iPSC-microglia models, as well as microglial xenotransplanted mice to provide proof of activity in human microglial in vivo.

RESULTS

We proved their efficacy in human iPSC microglia in vitro, as well as their pharmacological activity in vivo in a xenografted microglia model. We demonstrate ASOs targeting human microglia can modify their transcriptional profile and their response to amyloid-β plaques in vivo in a model of AD.

CONCLUSIONS

This study is the first proof-of-concept that human microglial can be modulated using ASOs in a dose-dependent manner to manipulate microglia phenotypes and response to neurodegeneration in vivo.

Sex Dimorphism in Pain Threshold and Neuroinflammatory Response: The Protective Effect of Female Sexual Hormones on Behavior and Seizures in an Allergic Rhinitis Model

Our previous research demonstrated that allergic rhinitis could impact behavior and seizure threshold in male mice. However, due to the complex hormonal cycles and hormonal influences on behavior in female mice, male mice are more commonly used for behavioral tests. In this study, we aimed to determine whether these findings were replicable in female mice and to explore the potential involvement of sexual hormones in regulating neuroinflammation in an allergic model. Our results indicate that pain threshold was decreased in female mice with allergic rhinitis and the levels of IL-23/IL-17A/IL-17R were increased in their Dorsal root ganglia. However, unlike males, female mice with AR did not display neuropsychological symptoms such as learning and memory deficits, depression, and anxiety-like behavior. This was along with decreased levels of DNA methyl transferase 1 (DNMT1) and inflammatory cytokines in their hippocampus. Ovariectomized mice were used to mitigate hormonal effects, and the results showed that they had behavioral changes and neuroinflammation in their hippocampus similar to male mice, as well as increased levels of DNMT1. These findings demonstrate sex differences in how allergic rhinitis affects behavior, pain sensitivity, and seizure thresholds. Furthermore, our data suggest that DNMT1 may be influenced by sexual hormones, which could play a role in modulating inflammation in allergic conditions.

Modulation of Gut Microbiota Through Dietary Intervention in Neuroinflammation and Alzheimer's and Parkinson's Diseases

PURPOSE OF REVIEW

The gut microbiota plays a crucial role in the pathogenesis of neuroinflammation and Alzheimer's and Parkinson's diseases. One of the main modulators of the gut microbiota is the diet, which directly influences host homeostasis and biological processes. Some dietary patterns can affect neurodegenerative diseases' progression through gut microbiota composition, gut permeability, and the synthesis and secretion of microbial-derived neurotrophic factors and neurotransmitters. This comprehensive review critically assesses existing studies investigating the impact of dietary interventions on the modulation of the microbiota in relation to neurodegenerative diseases and neuroinflammation.

RECENT FINDINGS

There are limited studies on the effects of specific diets, such as the ketogenic diet, Mediterranean diet, vegetarian diet, and Western diet, on the progression of neuroinflammation and Alzheimer's and Parkinson's diseases through the gut-brain axis. The ketogenic diet displays promising potential in ameliorating the clinical trajectory of mild cognitive impairment and Alzheimer's disease. However, conflicting outcomes were observed among various studies, highlighting the need to consider diverse types of ketogenic diets and their respective effects on clinical outcomes and gut microbiota composition. Vegetarian and Mediterranean diets, known for their anti-inflammatory properties, can be effective against Parkinson's disease, which is related to inflammation in the gut environment. On the other hand, the westernization of dietary patterns was associated with reduced gut microbial diversity and metabolites, which ultimately contributed to the development of neuroinflammation and cognitive impairment. Various studies examining the impact of dietary interventions on the gut-brain axis with regard to neuroinflammation and Alzheimer's and Parkinson's diseases are thoroughly reviewed in this article. A strong mechanistic explanation is required to fully understand the complex interactions between various dietary patterns, gut microbiota, and microbial metabolites and the effects these interactions have on cognitive function and the progression of these diseases.

Effect of prednisolone in a kindling model of epileptic seizures in rats on cytokine and intestinal microbiota diversity

Epilepsy is a neurological disease characterized by spontaneous and recurrent seizures. Epileptic seizures can be initiated and facilitated by inflammatory mechanisms. As the dysregulation of the immune system would be involved in epileptogenesis, it is suggested that anti-inflammatory medications could impact epileptic seizures. These medications could potentially have a side effect by altering the structure and composition of the intestinal microbiota. These changes can disrupt microbial homeostasis, leading to dysbiosis and potentially exacerbating intestinal inflammation. We hypothesize that prednisolone may affect the development of epileptic seizures, potentially influencing the diversity of the intestinal microbiota and the regulation of pro-inflammatory cytokines in intestinal tissue. This study aimed to evaluate the effects of prednisolone treatment on epileptic seizures and investigate the effect of this drug on the bacterial diversity of the intestinal microbiota and markers of inflammatory processes in intestinal tissue. We used Male Wistar rat littermates (n = 31, 90-day-old) divided into four groups: positive control treated with 2 mg/kg of diazepam (n = 6), negative control treated with 0.9 g% sodium chloride (n = 6), and the remaining two groups were subjected to treatment with prednisolone, with one receiving 1 mg/kg (n = 9) and the other 5 mg/kg (n = 10). All administrations were performed intraperitoneally (i.p.) over 14 days. To induce the chronic model of epileptic seizures, we administered pentylenetetrazole (PTZ) 25 mg/kg i.p. on alternate days. Seizure latency (n = 6 - 10) and TNF-α and IL-1β concentrations from intestinal samples were measured by ELISA (n = 6 per group), and intestinal microbiota was evaluated with intergenic ribosomal RNA (rRNA) spacer (RISA) analysis (n = 6 per group). The prednisolone treatment demonstrated an increase in the latency time of epileptic seizures and TNF-α and IL-1β concentrations compared to controls. There was no statistically significant difference in intestinal microbiota diversity between the different treatments. However, there was a strong positive correlation between microbial diversity and TNF-α and IL-1β concentrations. The administration of prednisolone yields comparable results to diazepam on increasing latency between seizures, exhibiting promise for its use in clinical studies. Although there were no changes in intestinal microbial diversity, the increase in the TNF-α and IL-1β cytokines in intestinal tissue may be linked to immune system signaling pathways involving the intestinal microbiota. Additional research is necessary to unravel the intricacies of these pathways and to understand their implications for clinical practice.

PM2.5 exposure upregulates pro-inflammatory protein expression in human microglial cells via oxidant stress and TLR4/NF-κB pathway

Exposure to ambient PM2.5 is associated with neurodegenerative disorders, in which microglia activation plays a critical role. Thus far, the underlying mechanisms for PM2.5-induced microglia activation have not been well elucidated. In this study, a human microglial cell line (HMC3) was used as the in vitro model to examine the inflammatory effect (hall marker of microglia activation) of PM2.5 and regulatory pathways. The expression of inflammatory mediators including interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2) as well as the brain derived neurotrophic factor (BDNF) were determined by ELISA and/or real-time PCR, respectively. Flow cytometry was used to measure the production of intracellular reactive oxygen species (ROS). Western blot was used to measure protein levels of Toll-like receptor 4 (TLR4), NF-κB inhibitor α (IκBα) and COX-2. It was shown that PM2.5 stimulation increased IL-6 and COX-2 expression but decreased BDNF expression in a dose-dependent manner. Further studies showed that PM2.5 triggered the formation of ROS and pre-treatment with the ROS scavenger acetylcysteine (NAC) significantly suppressed PM2.5-induced IL-6 and COX-2 expression. Moreover, the nuclear factor kappa B (NF-κB) inhibitor BAY11-7085 or the TLR4 neutralizing antibody markedly blocked PM2.5-induced IL-6 and COX-2 expression. However, NAC or BAY11-7085 exhibited minimal effect on PM2.5-induced BDNF down-regulation. In addition, pre-treatment with BAY11-7085 or TLR4 neutralizing antibody reduced ROS production induced by PM2.5, and NAC pre-treatment inhibited TLR4 expression and NF-κB activation induced by PM2.5. Collectively, PM2.5 treatment induced IL-6 and COX-2 but suppressed BDNF expression. PM2.5-induced IL-6 and COX-2 expression was mediated by interactive oxidative stress and TLR4/NF-κB pathway.

Mouse serum albumin induces neuronal apoptosis and tauopathies

The elderly frequently present impaired blood-brain barrier which is closely associated with various neurodegenerative diseases. However, how the albumin, the most abundant protein in the plasma, leaking through the disrupted BBB, contributes to the neuropathology remains poorly understood. We here demonstrated that mouse serum albumin-activated microglia induced astrocytes to A1 phenotype to remarkably increase levels of Elovl1, an astrocytic synthase for very long-chain saturated fatty acids, significantly promoting VLSFAs secretion and causing neuronal lippoapoptosis through endoplasmic reticulum stress response pathway. Moreover, MSA-activated microglia triggered remarkable tau phosphorylation at multiple sites through NLRP3 inflammasome pathway. Intracerebroventricular injection of MSA into the brains of C57BL/6J mice to a similar concentration as in patient brains induced neuronal apoptosis, neuroinflammation, increased tau phosphorylation, and decreased the spatial learning and memory abilities, while Elovl1 knockdown significantly prevented the deleterious effect of MSA. Overall, our study here revealed that MSA induced tau phosphorylation and neuron apoptosis based on MSA-activated microglia and astrocytes, respectively, showing the critical roles of MSA in initiating the occurrence of tauopathies and cognitive decline, and providing potential therapeutic targets for MSA-induced neuropathology in multiple neurodegenerative disorders.

Pathological high intraocular pressure induces glial cell reactive proliferation contributing to neuroinflammation of the blood-retinal barrier via the NOX2/ET-1 axis-controlled ERK1/2 pathway

BACKGROUND

NADPH oxidase (NOX), a primary source of endothelial reactive oxygen species (ROS), is considered a key event in disrupting the integrity of the blood-retinal barrier. Abnormalities in neurovascular-coupled immune signaling herald the loss of ganglion cells in glaucoma. Persistent microglia-driven inflammation and cellular innate immune system dysregulation often lead to deteriorating retinal degeneration. However, the crosstalk between NOX and the retinal immune environment remains unresolved. Here, we investigate the interaction between oxidative stress and neuroinflammation in glaucoma by genetic defects of NOX2 or its regulation via gp91ds-tat.

METHODS

Ex vivo cultures of retinal explants from wildtype C57BL/6J and Nox2 -/- mice were subjected to normal and high hydrostatic pressure (Pressure 60 mmHg) for 24 h. In vivo, high intraocular pressure (H-IOP) was induced in C57BL/6J mice for two weeks. Both Pressure 60 mmHg retinas and H-IOP mice were treated with either gp91ds-tat (a NOX2-specific inhibitor). Proteomic analysis was performed on control, H-IOP, and treatment with gp91ds-tat retinas to identify differentially expressed proteins (DEPs). The study also evaluated various glaucoma phenotypes, including IOP, retinal ganglion cell (RGC) functionality, and optic nerve (ON) degeneration. The superoxide (O2-) levels assay, blood-retinal barrier degradation, gliosis, neuroinflammation, enzyme-linked immunosorbent assay (ELISA), western blotting, and quantitative PCR were performed in this study.

RESULTS

We found that NOX2-specific deletion or activity inhibition effectively attenuated retinal oxidative stress, immune dysregulation, the internal blood-retinal barrier (iBRB) injury, neurovascular unit (NVU) dysfunction, RGC loss, and ON axonal degeneration following H-IOP. Mechanistically, we unveiled for the first time that NOX2-dependent ROS-driven pro-inflammatory signaling, where NOX2/ROS induces endothelium-derived endothelin-1 (ET-1) overexpression, which activates the ERK1/2 signaling pathway and mediates the shift of microglia activation to a pro-inflammatory M1 phenotype, thereby triggering a neuroinflammatory outburst.

CONCLUSIONS

Collectively, we demonstrate for the first time that NOX2 deletion or gp91ds-tat inhibition attenuates iBRB injury and NVU dysfunction to rescue glaucomatous RGC loss and ON axon degeneration, which is associated with inhibition of the ET-1/ERK1/2-transduced shift of microglial cell activation toward a pro-inflammatory M1 phenotype, highlighting NOX2 as a potential target for novel neuroprotective therapies in glaucoma management.

TRIM28 Fosters Microglia Ferroptosis via Autophagy Modulation to Enhance Neuropathic Pain and Neuroinflammation

This study explores the molecular underpinnings of neuropathic pain (NPP) and neuroinflammation, focusing on the role of TRIM28 in the regulation of autophagy and microglia ferroptosis. Leveraging transcriptomic data associated with NPP, we identified TRIM28 as a critical regulator of ferroptosis. Through comprehensive analysis, including Gene Ontology enrichment and protein-protein interaction network assessments, we unveiled GSK3B as a downstream target of TRIM28. Experimental validation confirmed the capacity of TRIM28 to suppress GSK3B expression and attenuate autophagic processes in microglia. We probed the consequences of autophagy and ferroptosis on microglia physiology, iron homeostasis, oxidative stress, and the release of proinflammatory cytokines. In a murine model, we validated the pivotal role of TRIM28 in NPP and neuroinflammation. Our analysis identified 20 ferroptosis regulatory factors associated with NPP, with TRIM28 emerging as a central orchestrator. Experimental evidence affirmed that TRIM28 governs microglial iron homeostasis and cell fate by downregulating GSK3B expression and modulating autophagy. Notably, autophagy was found to influence oxidative stress and proinflammatory cytokine release through the iron metabolism pathway, ultimately fueling neuroinflammation. In vivo experiments provided conclusive evidence of TRIM28-mediated pathways contributing to heightened pain sensitivity in neuroinflammatory states. The effect of TRIM28 on autophagy and microglia ferroptosis drives NPP and neuroinflammation. These findings offer promising avenues for identifying novel therapeutic targets to manage NPP and neuroinflammation.

Glucose-modified BSA/procyanidin C1 NPs penetrate the blood-brain barrier and alleviate neuroinflammation in Alzheimer's disease models

Alzheimer's disease (AD) is a chronic neurodegenerative disease with high prevalence, long duration and poor prognosis. The blood-brain barrier (BBB) is a physiologic barrier in the central nervous system, which hinders the entry of most drugs into the brain from the blood, thus affecting the efficacy of drugs for AD. Natural products are recognized as one of the promising and unique therapeutic approaches to treat AD. To improve the efficiency and therapeutic effect of the drug across the BBB, a natural polyphenolic compound, procyanidin C-1 (C1) was encapsulated in glucose-functionalized bovine serum albumin (BSA) nanoparticles to construct Glu-BSA/C1 NPs in our study. Glu-BSA/C1 NPs exhibited good stability, slow release, biocompatibility and antioxidant properties. In addition, Glu-BSA/C1 NPs penetrated the BBB, accumulated in the brain by targeting Glut1, and maintained the BBB integrity both in vitro and in vivo. Moreover, Glu-BSA/C1 NPs alleviated memory impairment of 5 × FAD mice by reducing Aβ deposition and Tau phosphorylation and promoting neurogenesis. Mechanistically, Glu-BSA/C1 NPs significantly activated the PI3K/AKT pathway and inhibited the NLRP3/Caspase-1/IL-1β pathway thereby suppressing neuroinflammation. Taken together, Glu-BSA/C1 NPs could penetrate the BBB and mitigate neuroinflammation in AD, which provides a new therapeutic approach targeting AD.

Itaconate alleviates anesthesia/surgery-induced cognitive impairment by activating a Nrf2-dependent anti-neuroinflammation and neurogenesis via gut-brain axis

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a common neurological complication of anesthesia and surgery in aging individuals. Neuroinflammation has been identified as a hallmark of POCD. However, safe and effective treatments of POCD are still lacking. Itaconate is an immunoregulatory metabolite derived from the tricarboxylic acid cycle that exerts anti-inflammatory effects by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In this study, we investigated the effects and underlying mechanism of 4-octyl itaconate (OI), a cell-permeable itaconate derivative, on POCD in aged mice.

METHODS

A POCD animal model was established by performing aseptic laparotomy in 18-month-old male C57BL/6 mice under isoflurane anesthesia while maintaining spontaneous ventilation. OI was intraperitoneally injected into the mice after surgery. Primary microglia and neurons were isolated and treated to lipopolysaccharide (LPS), isoflurane, and OI. Cognitive function, neuroinflammatory responses, as well as levels of gut microbiota and their metabolites were evaluated. To determine the mechanisms underlying the therapeutic effects of OI in POCD, ML385, an antagonist of Nrf2, was administered intraperitoneally. Cognitive function, neuroinflammatory responses, endogenous neurogenesis, neuronal apoptosis, and Nrf2/extracellular signal-related kinases (ERK) signaling pathway were evaluated.

RESULTS

Our findings revealed that OI treatment significantly alleviated anesthesia/surgery-induced cognitive impairment, concomitant with reduced levels of the neuroinflammatory cytokines IL-1β and IL-6, as well as suppressed activation of microglia and astrocytes in the hippocampus. Similarly, OI treatment inhibited the expression of IL-1β and IL-6 in LPS and isoflurane-induced primary microglia in vitro. Intraperitoneal administration of OI led to alterations in the gut microbiota and promoted the production of microbiota-derived metabolites associated with neurogenesis. We further confirmed that OI promoted endogenous neurogenesis and inhibited neuronal apoptosis in the hippocampal dentate gyrus of aged mice. Mechanistically, we observed a decrease in Nrf2 expression in hippocampal neurons both in vitro and in vivo, which was reversed by OI treatment. We found that Nrf2 was required for OI treatment to inhibit neuroinflammation in POCD. The enhanced POCD recovery and promotion of neurogenesis triggered by OI exposure were, at least partially, mediated by the activation of the Nrf2/ERK signaling pathway.

CONCLUSIONS

Our findings demonstrate that OI can attenuate anesthesia/surgery-induced cognitive impairment by stabilizing the gut microbiota and activating Nrf2 signaling to restrict neuroinflammation and promote neurogenesis. Boosting endogenous itaconate or supplementation with exogenous itaconate derivatives may represent novel strategies for the treatment of POCD.

Pan-neuronal expression of human mutant SOD1 in Drosophila impairs survival and motor performance, induces early neuroinflammation and chromosome aberrations

Several mutations in the SOD1 gene encoding for the antioxidant enzyme Superoxide Dismutase 1, are associated with amyotrophic lateral sclerosis, a rare and devastating disease characterized by motor neuron degeneration and patients' death within 2-5 years from diagnosis. Motor neuron loss and related symptomatology manifest mostly in adult life and, to date, there is still a gap of knowledge on the precise cellular and molecular events preceding neurodegeneration. To deepen our awareness of the early phases of the disease, we leveraged two Drosophila melanogaster models pan-neuronally expressing either the mutation A4V or G85R of the human gene SOD1 (hSOD1A4V or hSOD1G85R). We demonstrate that pan-neuronal expression of the hSOD1A4V or hSOD1G85R pathogenic construct impairs survival and motor performance in transgenic flies. Moreover, protein and transcript analysis on fly heads indicates that mutant hSOD1 induction stimulates the glial marker Repo, up-regulates the IMD/Toll immune pathways through antimicrobial peptides and interferes with oxidative metabolism. Finally, cytological analysis of larval brains demonstrates hSOD1-induced chromosome aberrations. Of note, these parameters are found modulated in a timeframe when neurodegeneration is not detected. The novelty of our work is twofold: we have expressed for the first time hSOD1 mutations in all neurons of Drosophila and confirmed some ALS-related pathological phenotypes in these flies, confirming the power of SOD1 mutations in generating ALS-like phenotypes. Moreover, we have related SOD1 pathogenesis to chromosome aberrations and antimicrobial peptides up-regulation. These findings were unexplored in the SOD1-ALS field.

Neuroprotective potential of pyrazole benzenesulfonamide derivative T1 in targeted intervention against PTZ-induced epilepsy-like condition in in vivo zebrafish model

Epilepsy is a chronic neurological disease characterized by a persistent susceptibility to seizures. Pharmaco-resistant epilepsies, impacting around 30 % of patients, highlight the urgent need for improved treatments. Neuroinflammation, prevalent in epileptogenic brain regions, is a key player in epilepsy, prompting the search for new mechanistic therapies. Hence, in this study, we explored the anti-inflammatory potential of pyrazole benzenesulfonamide derivative (T1) against pentylenetetrazole (PTZ) induced epilepsy-like conditions in in-vivo zebrafish model. The results from the survival assay showed 79.97 ± 6.65 % at 150 µM of T1 compared to PTZ-group. The results from reactive oxygen species (ROS), apoptosis and histology analysis showed that T1 significantly reduces cellular damage due to oxidative stress in PTZ-exposed zebrafish. The gene expression analysis and neutral red assay results demonstrated a notable reduction in the inflammatory response in zebrafish pre-treated with T1. Subsequently, the open field test unveiled the anti-convulsant activity of T1, particularly at a concentration of 150 μM. Moreover, both RT-PCR and immunohistochemistry findings indicated a concentration-dependent potential of T1, which inhibited COX-2 in zebrafish exposed to PTZ. In summary, T1 protected zebrafish against PTZ-induced neuronal damage, and behavioural changes by mitigating the inflammatory response through the inhibition of COX-2.

Neuroprotective role of Carvacrol via Nrf2/HO-1/NLRP3 axis in Rotenone-induced PD mice model

Parkinson's disease (PD) is a multifactorial neurodegenerative disorder whose cause is unclear. Neuroinflammation is recognized as one of the major pathogenic mechanisms involved in the development and progression of PD. NLRP3 inflammasome is the most widely studied inflammatory mediator in various diseases including PD. Several phytoconstituents have shown neuroprotective role in PD. Carvacrol is a phenolic monoterpene commonly found in the essential oils derived from plants belonging to Lamiaceae family. It is well known for its anti-inflammatory and antioxidant properties and has been widely explored in several diseases. In this study, we explored the role of Carvacrol in suppressing neuroinflammation by regulating NLRP3 inflammasome through Nrf2/HO-1 axis and subsequently, inflammatory cytokines like IL-1β, IL-18 in Rotenone induced PD mice model. Three doses (25 mg/kg, 50 mg/kg, 100 mg/kg p.o.) of Carvacrol were administered to, respectively, three groups (LD, MD, HD), one hour after administration of Rotenone (1.5 mg/kg, i.p.), every day, for 21 days. Treatment with Carvacrol ameliorated the motor impairment caused by Rotenone. It alleviated neurotoxicity and reduced inflammatory cytokines. Further, Carvacrol also alleviated oxidative stress and increased antioxidant enzymes. From these results, we show that Carvacrol exerts neuroprotective effects in PD via anti-inflammatory and antioxidant mechanisms and could be a potential therapeutic option in PD.

PD-L1/PD-1 pathway: a potential neuroimmune target for pain relief

Pain is a common symptom of many diseases with a high incidence rate. Clinically, drug treatment, as the main method to relieve pain at present, is often accompanied by different degrees of adverse reactions. Therefore, it is urgent to gain a profound understanding of the pain mechanisms in order to develop advantageous analgesic targets. The PD-L1/PD-1 pathway, an important inhibitory molecule in the immune system, has taken part in regulating neuroinflammation and immune response. Accumulating evidence indicates that the PD-L1/PD-1 pathway is aberrantly activated in various pain models. And blocking PD-L1/PD-1 pathway will aggravate pain behaviors. This review aims to summarize the emerging evidence on the role of the PD-L1/PD-1 pathway in alleviating pain and provide an overview of the mechanisms involved in pain resolution, including the regulation of macrophages, microglia, T cells, as well as nociceptor neurons. However, its underlying mechanism still needs to be further elucidated in the future. In conclusion, despite more deep researches are needed, these pioneering studies indicate that PD-L1/PD-1 may be a potential neuroimmune target for pain relief.

P2X7 receptor: a potential target for treating comorbid anxiety and depression

In clinical practice, depression and anxiety frequently coexist, and they are both comorbid with somatic diseases. The P2X7R is an adenosine 5'-triphosphate (ATP)-gated non-selective cation channel that is widely expressed in immune-related cells. Under conditions of stress, chronic pain, and comorbid chronic physical illness, P2X7R activation in glial cells leads to neuroinflammation. This could contribute to the development of anxiety and depression-related emotional disturbances. Previous studies have shown that the P2X7 receptor (P2X7R) plays an important role in the pathogenesis of both anxiety and depression. Thus, the P2X7R may play a role in the comorbidity of anxiety and depression. Positron emission tomography can be used to assess the degree and location of neuroinflammation by monitoring functional and expression-related changes in P2X7R, which can facilitate clinical diagnoses and guide the treatment of patients with anxiety and depression. Moreover, single nucleotide polymorphisms (SNPs) in the P2X7R gene are associated with susceptibility to different types of psychiatric disorders. Thus, evaluating the SNPs of the P2X7R gene could enable personalized mood disorder diagnoses and treatments. If the P2X7R were set as a therapeutic target, selective P2X7R antagonists may modulate P2X7R function, thereby altering the balance of intra- and extra-cellular ATP. This could have therapeutic implications for treating anxiety and depression, as well as for pain management. According to in vitro and in vivo studies, the P2X7R plays an important role in anxiety and depression. In this review, we consider the potential of the P2X7R as a therapeutic target for comorbid anxiety and depression, and discuss the potential diagnostic and therapeutic value of this receptor.

An overview of current advances in perinatal alcohol exposure and pathogenesis of fetal alcohol spectrum disorders

The adverse use of alcohol is a serious global public health problem. Maternal alcohol consumption during pregnancy usually causes prenatal alcohol exposure (PAE) in the developing fetus, leading to a spectrum of disorders known as fetal alcohol spectrum disorders (FASD) and even fetal alcohol syndrome (FAS) throughout the lifelong sufferers. The prevalence of FASD is approximately 7.7 per 1,000 worldwide, and is even higher in developed regions. Generally, Ethanol in alcoholic beverages can impair embryonic neurological development through multiple pathways leading to FASD. Among them, the leading mechanism of FASDs is attributed to ethanol-induced neuroinflammatory damage to the central nervous system (CNS). Although the underlying molecular mechanisms remain unclear, the remaining multiple pathological mechanisms is likely due to the neurotoxic damage of ethanol and the resultant neuronal loss. Regardless of the molecular pathway, the ultimate outcome of the developing CNS exposed to ethanol is almost always the destruction and apoptosis of neurons, which leads to the reduction of neurons and further the development of FASD. In this review, we systematically summarize the current research progress on the pathogenesis of FASD, which hopefully provides new insights into differential early diagnosis, treatment and prevention for patents with FASD.

Pro-inflammatory cytokines in stress-induced depression: Novel insights into mechanisms and promising therapeutic strategies

Stress-mediated depression is one of the common psychiatric disorders with a high prevalence and suicide rate, there is a lack of effective treatment. Accordingly, effective treatments with few adverse effects are urgently needed. Pro-inflammatory cytokines (PICs) may play a key role in stress-mediated depression. Thereupon, both preclinical and clinical studies have found higher levels of IL-1β, TNF-α and IL-6 in peripheral blood and brain tissue of patients with depression. Recent studies have found PICs cause depression by affecting neuroinflammation, monoamine neurotransmitters, hypothalamic pituitary adrenal axis and neuroplasticity. Moreover, they play an important role in the symptom, development and progression of depression, maybe a potential diagnostic and therapeutic marker of depression. In addition, well-established antidepressant therapies have some relief on high levels of PICs. Importantly, anti-inflammatory drugs relieve depressive symptoms by reducing levels of PICs. Collectively, reducing PICs may represent a promising therapeutic strategy for depression.

The firestorm within: A narrative review of extreme heat and wildfire smoke effects on brain health

Climate change is generating increased heatwaves and wildfires across much of the world. With these escalating environmental changes comes greater impacts on human health leading to increased numbers of people suffering from heat- and wildfire smoke-associated respiratory and cardiovascular impairment. One area of health impact of climate change that has received far less attention is the effects of extreme heat and wildfire smoke exposure on human brain health. As elevated temperatures, and wildfire-associated smoke, are increasingly experienced simultaneously over summer periods, understanding this combined impact is critical to management of human health especially in the elderly, and people with dementia, and other neurological disorders. Both extreme heat and wildfire smoke air pollution (especially particulate matter, PM) induce neuroinflammatory and cerebrovascular effects, oxidative stress, and cognitive impairment, however the combined effect of these impacts are not well understood. In this narrative review, a comprehensive examination of extreme heat and wildfire smoke impact on human brain health is presented, with a focus on how these factors contribute to cognitive impairment, and dementia, one of the leading health issues today. Also discussed is the potential impact of combined heat and wildfire smoke on brain health, and where future efforts should be applied to help advance knowledge in this rapidly growing and critical field of health research.

Deciphering the therapeutic potential of SheXiangXinTongNing: Interplay between gut microbiota and brain metabolomics in a CUMS mice model, with a focus on tryptophan metabolism

Depression, a prevalent and multifaceted mental disorder, has emerged as a significant public health concern due to its escalating prevalence and heightened risk of severe suicidality. Given its profound impact, the imperative for preventing and intervening in depression is paramount. Substantial evidence underscores intricate connections between depression and cardiovascular health. SheXiangXinTongNing (XTN), a recognized traditional Chinese medicine for treating Coronary Heart Disease (CHD), prompted our exploration into its antidepressant effects and underlying mechanisms. In this investigation, we assessed XTN's antidepressant potential using the chronic unpredictable mild stress (CUMS) mice model and behavioral tests. Employing network pharmacology, we delved into the intricate mechanisms at play. We characterized the microbial composition and function in CUMS mice, both with and without XTN treatment, utilizing 16S rRNA sequencing and metabolomics analysis. The joint analysis of these results via Cytoscape identified pivotal metabolic pathways. In the realm of network pharmacology, XTN administration exhibited antidepressant effects by modulating pathways such as IL-17, neuroactive ligand-receptor interaction, PI3K-Akt, cAMP, calcium, and dopamine synapse signaling pathways. Our findings revealed that XTN significantly mitigated depression-like symptoms and cognitive deficits in CUMS mice by inhibiting neuroinflammation and pyroptosis. Furthermore, 16S rRNA sequencing unveiled that XTN increased the alpha-diversity and beta-diversity of the gut microbiome in CUMS mice. Metabolomics analysis identified brain metabolites crucial for distinguishing between the CUMS and CUMS+XTN groups, with a focus on pathways like Tryptophan metabolism and Linoleic acid metabolism. Notably, specific bacterial families, including Alloprevotella, Helicobacter, Allobaculum, and Clostridia, exhibited robust co-occurring relationships with brain tryptophan metabolomics, hinting at the potential mediating role of gut microbiome alterations and metabolites in the efficacy of XTN treatment. In conclusion, our study unveils modifications in microbial compositions and metabolic functions may be pivotal in understanding the response to XTN treatment, offering novel insights into the mechanisms underpinning the efficacy of antidepressants.

Maresin1 improves hippocampal neuroinflammation and cognitive function in septic rats by activating the SLC7A11 / GPX4 ferroptosis signaling pathway

Sepsis-associated encephalopathy (SAE) is a prevalent complication of sepsis, with hippocampal neuroinflammation playing a crucial role in SAE-induced cognitive impairment. Maresin1 (MaR1), a bioactive docosahexaenoic acid (DHA) metabolite, demonstrates comprehensive anti-inflammatory and neuroprotective attributes. Yet, its protective efficacy against SAE-induced cognitive decline remains unexplored. In this investigation, we implemented a rat SAE model via cecal ligation and puncture (CLP), while lipopolysaccharide (LPS) stimulation of HT22 cells simulated an in vitro SAE model; both models were pre-treated with MaR1. We evaluated rat learning and memory using a water maze, assessed hippocampal neuron damage via Nissl and FJC staining, and observed mitochondrial alterations through TEM. In vivo and in vitro assays gauged levels of Fe2+, MDA, GSH, and SOD. Additionally, Iba1 expression in the hippocampus was examined via immunofluorescence, while SLC7A11 and GPX4 protein expression levels were determined using western blot. Our findings indicated CLP-induced learning and memory impairment in rats, along with heightened ROS, Fe2+, and MDA levels in hippocampal neurons, diminished GSH and SOD levels, and down-regulated ferroptosis-related proteins (GPX4 and SLC7A11). Remarkably, MaR1 treatment attenuated these adverse effects. In LPS-stimulated HT22 cells, MaR1 lowered lipid ROS and bolstered mitochondrial membrane potential. Nonetheless, the ferroptosis inducer Erastin reversed MaR1's protective effects. Transwell experiments further showed MaR1's potential to inhibit microglia activation triggered by ferroptosis in HT22 cells. Consequently, MaR1 may mitigate hippocampal neuroinflammation via activating the SLC7A11/GPX4 ferroptosis signaling pathway, thus ameliorating SAE-related cognitive impairment.

Polar lipids modify Alzheimer's Disease pathology by reducing astrocyte pro-inflammatory signaling through platelet-activating factor receptor (PTAFR) modulation

BACKGROUND

Pro-inflammatory processes triggered by the accumulation of extracellular amyloid beta (Aβ) peptides are a well-described pathology in Alzheimer's disease (AD). Activated astrocytes surrounding Aβ plaques contribute to inflammation by secreting proinflammatory factors. While astrocytes may phagocytize Aβ and contribute to Aβ clearance, reactive astrocytes may also increase Aβ production. Therefore, identifying factors that can attenuate astrocyte activation and neuroinflammation and how these factors influence pro-inflammatory pathways is important for developing therapeutic and preventive strategies in AD. Here, we identify the platelet-activating factor receptor (PTAFR) pathway as a key mediator of astrocyte activation. Intriguingly, several polar lipids (PLs) have exhibited anti-inflammatory protective properties outside the central nervous system through their inhibitory effect on the PTAFR pathway. Thus, we additionally investigated whether different PLs also exert inhibitory effects on the PAF pathway in astrocytes and whether their presence influences astrocytic pro-inflammatory signaling and known AD pathologies in vitro.

METHODS

PLs from salmon and yogurt were extracted using novel food-grade techniques and their fatty acid profile was determined using LC/MS. The effect of PLs on parameters such as astrocyte activation and generation of oxygen species (ROS) was assessed. Additionally, effects of the secretome of astrocytes treated with these polar lipids on aged neurons was measured.

RESULTS

We show that PLs obtained from salmon and yogurt lower astrocyte activation, the generation of reactive oxygen species (ROS), and extracellular Aβ accumulation. Cell health of neurons exposed to the secretome of astrocytes treated with salmon-derived PLs and Aβ was less affected than those treated with astrocytes exposed to Aβ only.

CONCLUSION

Our results highlight a novel underlying mechanism, why consuming PL-rich foods such as fish and dairy may reduce the risk of developing dementia and associated disorders.

Prussian blue analogues improves the microenvironment after spinal cord injury by regulating Zn

Mitochondrial injury, neuronal apoptosis and phenotypic transformation of macrophages are the main mechanisms of spinal cord injury. Based on the Prussian blue nanomase's strong ability to clear free radicals, the treatment of spinal cord injury with nano-zirconium (Pb-Zr) was carried out. The disease treatment strategy based on nanomaterials has excellent therapeutic effect, and Prussian blue analogs have good therapeutic properties, so the application prospects of Prussian blue analogs is broad. From the point of view of Prussian blue content, improving the presence of zirconium in the microenvironment significantly increased the activity of Prussian blue. Prussian Blue zirconium significantly improved lipopolysaccharide (LPS) and interferon (IFN-γ) induced neuronal cell (pc12 cells) and macrophage dysfunction by improving oxidative stress, inflammation, and apoptosis in the microenvironment. It can promote the recovery of motor function after spinal cord injury. In vivo experiments, it shows that Prussian blue zirconium can improve inflammation, apoptosis and oxidative stress of spinal cord tissue, promote regenerative therapy after spinal cord injury, and improve motor function. Moreover, it has been reported that high-priced Zr4+ cations can regulate the deposition and nucleation behavior of Zn2+ in high-performance zinc metal anodes. Therefore, we propose the hypothesis that Pb-Zr modulates Zn2+ be used to promote recovery from spinal cord injury. The results show that nanomaterial is beneficial in the treatment of spinal cord injury. This study provides a good prospect for the application of spinal cord injury treatment. It also provides an important feasibility for subsequent clinical conversions.

Fibrinogen deposition promotes neuroinflammation and fibrin-derived γ377-395 peptide ameliorates neurological deficits after ischemic stroke

BACKGROUND

Fibrin(ogen) deposition in the central nervous system (CNS) contributes to neuropathological injury; however, its role in ischemic stroke is unknown. In this study, we identified fibrinogen as a novel proinflammatory regulator of post-stroke neuroinflammation and revealed the neuro-protection effect of fibrin-derived γ377-395peptide in stroke.

METHODS

Fibrinogen depletion and fibrinogen-derived γ377-395peptide treatment were performed 2 h after establishing a permanent middle cerebral artery occlusion (pMCAO) model. The infarction volume, neurological score, fibrin(ogen) deposition, and inflammatory response were evaluated 24 h after occlusion. Both in vivo and in vitro studies were conducted to assess the therapeutic potential of the γ377-395peptide in blocking the interactions between fibrin(ogen) and neutrophils.

RESULTS

Fibrin(ogen) deposited in the infarct core promoted post-stroke inflammation and exacerbated neurological deficits in the acute phase after stroke onset. Reducing fibrinogen deposition resulted in a decrease in infarction volume, improved neurological scores, and reduced inflammation in the brain. Additionally, the presence of neutrophil accumulation near fibrin(ogen) deposits was observed in ischemic lesions, and the engagement of fibrin(ogen) by integrin receptor αMβ2 promoted neutrophil activation and post-stroke inflammation. Finally, inhibiting fibrin(ogen)-mediated neutrophil activation using a fibrinogen-derived γ377-395peptide significantly attenuated neurological deficits.

CONCLUSIONS

Fibrin(ogen) is a crucial regulator of post-stroke inflammation and contributes to secondary brain injury. The inflammation induced by fibrin(ogen) is primarily driven by neutrophils during acute ischemic stroke and can be ameliorated using the fibrin-derived γ377-395peptide. Targeting the fibrin(ogen)-mediated neuropathological process represents a promising approach for neuroprotective therapy after stroke while preserving its beneficial coagulation function.