Journal of neuroimmune pharmacology : the official journal of the Society on NeuroImmune Pharmacology最新文献

Emerging evidence highlights the significance of peripheral inflammation in the pathogenesis of Parkinson's disease (PD) and suggests the gut as a viable therapeutic target. This study aimed to explore the neuroprotective effects of the probiotic formulation VSL#3^® and its underlying mechanism in a PD mouse model induced by MPTP. Following MPTP administration, the striatal levels of dopamine and its metabolites, as along with the survival rate of dopaminergic neurons in the substantia nigra, were significantly reduced in PD mice. MPTP also significantly increased the mRNA expression of pro-inflammatory cytokines TNF-α and IL-1β, while reducing anti-inflammation mediators, like glia cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) in the striatum. These pathological changes were notably mitigated by VSL#3^® treatment, suggesting its neuroprotective and anti-inflammatory effects in the brain. Additionally, VSL#3^® significantly lowered the circulating levels of pro-inflammatory cytokines, and reduced TNF-α and IL-1β mRNA expression in the liver, indicating an inhibition of cytokine transfer. In the intestine, the probiotic treatment markedly decreased the mRNA expression of pro-inflammatory cytokines, (TNF-α, IL-1β, IL-6 and IL-17), and the other two key components of the NLRP3 inflammasome, caspase-1 and NLRP3, demonstrating an inhibition of VSL#3^® on gut NLRP3 inflammasome. VSL#3^® exerts neuroprotective effects in PD mice through the suppression of intestinal inflammation, particularly inhibiting the intestinal NLRP3 inflammasome. This study supports the therapeutic potential of targeting intestinal inflammation and utilizing probiotics in PD treatment.

IL-2/IL-2R inhibition improved the prognosis of ischemic stroke by regulating T cells, while the respective contribution of T cells with high/medium/low-affinity IL-2 receptors remained unclear. Single-cell RNA sequencing data of ischemic brain tissue revealed that most of the high-affinity IL-2R would be expressed by CD8 + T cells, especially by a highly-proliferative subset. Interestingly, only the CD8 + T cells with high-affinity IL-2R infiltrated ischemic brain tissues, highly expressing 32 genes (including Cdc20, Cdca3/5, and Asns) and activating 7 signaling pathways (including the interferon-alpha response pathway, a key mediator in the proliferation, migration, and cytotoxicity of CD8 + T cells). Its interaction with endothelial cells and the ligand-receptor interaction analysis also suggested an augmented brain infiltration after cerebral ischemia. In IL-2Rα KO mice, who would have no high- or low-affinity IL-2R in CD8 + T cells, the RNA-seq, qPCR, immunofluorescence, and multiplex assays found that the expression of CD8b, CD122, CD132, and Vcam-1 was upregulated in the acute phase of cerebral ischemia, with decreasing H2-k1 positive cells and increasing Vcam-1 and CD8b positive cells in brain tissue. However, inflammation pathways in brain were inhibited and peripheral inflammatory cytokine levels were reduced, indicating that CD8 + T cells changed into an anti-inflammatory phenotype. The IL-2Rα KO mice after cerebral ischemia also performed better in behavioral tests and had more favorable results in diffusion tensor imaging, electrophysiology, and MBP testing. Our findings suggested that the CD8 + T cells with high-affinity IL-2R, as well as IL-2Rα, might be targeted to improve the clinical management of ischemic stroke.

Parkinson's disease (PD) is a complex progressive neurodegenerative disorder and the pathogenesis and treatment methods are unknown. This aim is to investigate the effects of long non coding RNA NEAT1 (LncRNA NEAT1) on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD). Immunoprecipitation and western blot were used to search for the effects of LncRNA NEAT1 on PD. Tyrosine hydroxylase (TH) and brain derived neurotrophic factor (BDNF) were evaluated in substantia nigra (SN) region of the brain by immunohistochemical staining. Compared with the control group, the relative expression level of LncRNA NEAT1 in the MPTP group was significantly increased. LncRNA NEAT1 is negatively correlated with miR-376b-3p. LncRNA NEAT1 significantly increased oxidative stress, neuroinflammation along with enhanced neurotrophic potential via NLR family Pyrin domain protein 3 (NLRP3) pathway. In conclusion, these results indicated that LncRNA NEAT1 participated in the pathophysiological of PD and its mechanism via the miR-376b-3p/NLRP3 signaling pathway.

Microglial polarization and ferroptosis are important pathological features in Alzheimer's disease (AD). Ghrelin, a brain-gut hormone, has potential neuroprotective effects in AD. This study aimed to explore the potential mechanisms by which ghrelin regulates the progression of AD, as well as the crosstalk between microglial polarization and ferroptosis. Mouse BV2 microglial cells and male mice were treated with beta-amyloid (Aβ) (1-42) to simulate the AD environment. Microglia ferroptosis was measured by detecting levels of ferroptosis-related proteins (SLC7A11, GPX4, FTL1, and FTH1), metabolic markers (ROS, MDA, GSH, SOD), and observing mitochondrial morphological changes. Microglial polarization was evaluated by measuring levels of inflammatory markers and surface markers. The impact of ghrelin on Aβ_1-42-exposed microglia was assessed by coupling with the ferroptosis activator Erastin. Cognitive impairment in AD mice was evaluated through behavioral tests. Tissue staining was applied to determine neuronal damage. In Aβ_1-42-exposed microglia, ghrelin upregulated the protein expression of SLC7A11, GPX4, FTL1 and FTH1, reduced ROS and MDA levels, and elevated GSH and SOD levels through the BMP6/SMAD1 pathway. Ghrelin alleviated mitochondrial structural damage. Additionally, ghrelin reduced levels of pro-inflammatory factors and CD86, while increasing levels of anti-inflammatory factors and CD206. Erastin reversed the effects of ghrelin on ferroptosis and phenotypic polarization in Aβ_1-42-exposed microglia. In AD mice, ghrelin ameliorated abnormal behavior, neuroinflammation, and plaque deposition. Ghrelin attenuated iNOS/IBA1-positive expression and enhanced Arg-1/IBA1-positive expression in the hippocampus. Ghrelin induces microglial M2 polarization by inhibiting microglia ferroptosis, thereby alleviating neuroinflammation. Our results indicate that ghrelin may serve as a promising potential agent for treating cognitive impairment in AD.

Empagliflozin (EMPA) is one of the sodium/glucose cotransporter 2 (SGLT2) inhibitors that has been recently approved for the treatment of diabetes mellitus type II. Recently, EMPA has shown protective effects in different neurological disorders, besides its antidiabetic activity. Kindling is a relevant model to study epilepsy and neuroplasticity. This study aimed to investigate the potential protective effects of EMPA (1 and 3 mg/kg orally) against convulsant effects induced by pentylenetetrazole (PTZ) using a modified window- (win-) PTZ kindling protocol. The biochemical dysfunction and hippocampal damage induced by PTZ were profoundly reversed by EMPA treatment in a dose-dependent manner, as evidenced by the significant increase in reduced glutathione (GSH) and decrease in malondialdehyde (MDA) hippocampal contents. Furthermore, EMPA counteracted PTZ-induced neuronal damage in the hippocampal region, as confirmed by histopathological examination of the hippocampal tissues. EMPA impaired astrocytosis and showed an antiapoptotic effect through a significant reduction of glial fibrillary acidic protein (GFAP) and BCL2-Associated X Protein (BAX) expressions, respectively. Interestingly, EMPA exhibited an antiepileptic effect against PTZ-induced seizures through significantly reducing neuronal PAS domain Protein 4 (Npas4), cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) hippocampal expressions, and enhancing the brain-derived neurotrophic factor (BDNF)-tropomyosin receptor kinase B (TrkB) pathway, which are found to be involved in epileptogenesis, eventually leading to significant improvement of behavioral impairments induced by PTZ. Hence, these results showed further prospective insights for EMPA as a neuroprotective agent.

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder of complex pathogenesis and multiple interacting signaling pathways where amyloidal-β protein (Aβ) clearance plays a crucial role in cognitive decline. Herein, the current study investigated the possible modulatory effects of memantine/ rosuvastatin therapy on TGF-β1/p-Smad/p21 signaling pathway and their correlation to the blood brain barrier transporters involved in Aβ-clearance and microRNAs as a novel molecular mechanism in AD treatment. AD was induced by a single intracerebroventricular streptozotocin injection (ICV-STZ, 3 mg/kg) in rats and drug therapy was continued for 28 days after AD induction. Efficacy was monitored by applying a battery of behavioral assessments, as well as biochemical, histopathological, molecular and gene expression techniques. The upregulated TGF-β1-signaling in the untreated rats was found to be highly correlated to transporters and microRNAs governing Aβ-efflux; ABCA1/miRNA-26 and LRP1/miRNA-205 expressions, rather than RAGE/miRNA-185 controlling Aβ-influx; an effect that was opposed by the tested drugs and was found to be correlated with the abolished TGF-β1-signaling as well. Combined memantine/rosuvastatin therapy ameliorated the STZ evoked decreases in escape latency and number of crossovers in the Morris water maze test, % spontaneous alternation in the Y-maze test, and discrimination and recognition indices in the object recognition test. The evoked behavioral responses were directly related to the β-amyloid accumulation and the alteration in its clearance. Additionally, drug treatment increased brain glutathione and decreased malondialdehyde levels. These findings were histopathologically confirmed by a marked reduction of gliosis and restoration of neuronal integrity in the CA1 region of the hippocampus of the AD rats. These findings implicated that the memantine/rosuvastatin combination could offer a new therapeutic potential for AD management by abrogating the TGF-β1/p-Smad2/p21 pathway and regulating Aβ-clearance.

Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra that primarily affects movement control. Neuroinflammation plays a pivotal role in driving the disease's progression. The persistent inflammatory state in the brain exacerbates neuronal damage, creating a cycle that perpetuates the neurodegenerative process. Glucocorticoids, such as dexamethasone, have potent anti-inflammatory properties and have been studied for their neuroprotective potential in different neurodegenerative diseases. However, their specific impact on PD remains unclear. This study aimed to evaluate the impact of dexamethasone on a neuromelanin (NM)-driven model of PD. We demonstrated that dexamethasone administration significantly improved motor function and preserved dopaminergic neuron compared to untreated controls in our study. These neuroprotective effects were mediated, at least in part, by suppressing reactive microglia and reducing the infiltration of peripheral immune cells into the brain. Our findings underscore the potential therapeutic benefits of dexamethasone in mitigating neuroinflammation and maintaining neuronal integrity in a NM-driven model of PD. These results advocate for further investigation into glucocorticoid-based therapies as adjunctive treatments for PD, particularly in scenarios where neuroinflammation contributes prominently to disease progression.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by the expansion of a CAG trinucleotide repeat in the huntingtin (HTT) gene. When the CAG repeat exceeds 36, it results in the accumulation of the mutant HTT (mHTT) protein in neurons and glial cells. Key pathological mechanisms in HD include excitotoxicity, energy dysfunction, impaired mitochondrial function, increased oxidative stress, and neuroinflammation. The NLRP3 inflammasome is a multimeric protein complex element of NLRP3, ASC, and caspase-1, which regulates interleukin (IL)-1β and IL-18 secretion. The NLRP3 inflammasome plays an important role in inflammatory reactions and is involved in the pathogenesis of several neurodegenerative diseases. We have previously demonstrated high NLRP3 inflammasome expression levels in the striatum of R6/2 mice (a transgenic HD mouse model). Systematic administration of an NLRP3 inhibitor (MCC950) to R6/2 mice suppressed the NLRP3 inflammasome, decreased IL-1β and reactive oxygen species production, and reduced neuronal toxicity, suggesting protective effects against HD. Antrodia cinnamomea is an indigenous medicinal fungus in Taiwan, which shows diverse medicinal and pharmacological activities, but its effects in HD are not well understood. Herein, we report that systematic administration of Antcin-H isolated from A. cinnamomea to R6/2 mice suppressed the NLRP3 inflammasome, IL-1β production, and reduced neuronal toxicity. Most importantly, oral administration of Antcin-H reduced disease progression by increasing neuronal survival, reducing neuroinflammation during an extended lifespan, and improving motor dysfunction in R6/2 mice. Taken together, our data suggest that Antcin-H has therapeutic potential for treating HD.

Infection with human immunodeficiency virus (HIV) increases risk for maladies of the gut barrier, which promotes sustained systemic inflammation even in virally controlled patients. We previously revealed morphological disorganization of colon epithelial barrier proteins in HIV-1 transgenic (Tg) rats. The current study evaluated mechanisms that may underlie gut barrier pathology induced by toxic HIV-1 proteins. Methamphetamine (meth) use is prevalent among HIV-infected individuals, and meth can exaggerate morbidity of HIV infection. Thus, we determined whether meth exposure worsened HIV-associated gut pathology using colon samples from HIV-1 Tg and non-Tg rats that self-administered meth 2 h/day for 21 days. Immunoblotting was conducted for occludin (a gut barrier protein) and matrix metalloproteinase-9 (MMP-9; a proteinase regulator of occludin). Colon levels of occludin were decreased, and MMP-9 levels and activity were increased in HIV-1 Tg rats. A Pearson correlation revealed an inverse relationship between occludin levels and MMP-9 activity. Doses of meth that were self-administered by Tg rats were lower than other rat models. Meth-induced trends in non-Tg rats were not significant, and meth did not exaggerate effects seen in Tg rats. Accordingly, only the HIV-effects on epithelial function were explored further. Transepithelial resistance (TER) across a monolayer of human colon epithelial cells (Caco-2) was used to examine treatments with the HIV-1 toxic protein, Tat, and the ability of pioglitazone, a PPARγ agonist that inhibits MMP-9, to mitigate Tat-induced changes. Exposure to Tat for 24 h decreased TER, which co-occurred with decreases in levels of barrier tight junction proteins (occludin, claudin-1, and zonula occludens-1) and with increases in the level and activity of MMP-9. Pretreatment or post-treatment with pioglitazone respectively prevented and restored Tat-induced impairments of Caco-2 barrier. Thus, while low doses of meth did not alter barrier proteins in the current study, exposure to HIV-1 proteins disrupted the gut barrier, and this action involved a dysregulation of MMP-9.