The management of cognitive impairments in schizophrenia presents a considerable challenge, with a strong association between neuroinflammation and its progression. Urolithin A (UA) demonstrates important anti-inflammatory properties in multiple neurological disease models, contributing to the enhancement of cognitive deficits. However, it remains uncertain if UA can produce comparable neuroregulatory effects in female rat models of schizophrenia. Eight-week-old female Sprague Dawley rats received either 0.1 mg/kg of MK801 or volume-matched saline via intraperitoneal injection for 5 consecutive days. Furthermore, they were administered 150 mg/kg of UA through oral gavage for 4 weeks. Behavioral assessments were performed to evaluate cognitive function and behavior after UA treatment. Immunofluorescence staining was employed to assess microglial activity in the hippocampus, while Western blot analysis was conducted to investigate the expression of neuroinflammation-associated proteins. Prolonged exposure to MK801 induces schizophrenia-like behaviors and cognitive deficits in female rats. It also elevates the expression of NLRP3, Caspase-1, IL-1β, and IL-18 proteins in the hippocampus, accompanied by the activation of microglial cells. However, UA treatment can reverse the expression of these inflammatory proteins and the activation of microglial cells induced by MK801. This is the first study to evaluate the effects of UA on behavior and cognition in a female rat model of schizophrenia. The findings indicate that UA mitigates MK-801-induced cognitive deficits in female rats by inhibiting neuroinflammation and microglial activation via modulation of the NLRP3 signaling pathway. These findings offer preclinical data endorsing the possible application of UA as a dietary supplement to prevent cognitive deficits in schizophrenia.

The immune system plays a critical role in regulating amyloid-beta (Aβ) metabolism in Alzheimer's Disease (AD). Both T and B lymphocytes are involved in the pathogenesis of AD. The sphingosine-1-phosphate (S1P) receptor modulator fingolimod used in the treatment of multiple sclerosis, can promote lymphocyte homing, potentially reducing the infiltration of peripheral lymphocytes into the brain.

In this study, 8-month-old APP/PS1 mice were orally administered fingolimod at a dose of 1 mg/kg/day or saline as a control for 2 months. After treatment, the mice were subjected to behavioral tests, pathological examinations, and biochemical analyses to evaluate behavioral deficits and AD-type pathologies.

Fingolimod inhibits the infiltration of peripheral lymphocytes into the brain and reduces neuroinflammation. Fingolimod enhances cognitive function and alleviates brain Aβ deposition. Additionally, fingolimod treatment mitigates other AD-related pathologies, including Tau hyperphosphorylation, neuroinflammation, and neurodegeneration. Proteomic analysis further confirms the therapeutic effects of fingolimod in AD, reflected by the downregulation of proteins involved in multiple AD-associated pathways.

This study illustrates that fingolimod effectively ameliorates multiple pathological features of AD, highlighting its potential as a promising therapeutic candidate for the disease.

Cognitive impairment in schizophrenia occurs in the early stages of the disease and is closely associated with prognosis. Alleviation of cognitive impairment in schizophrenia faces major challenges owing to the lack of preventive and therapeutic drugs that are novel and effective. Urolithin A (UA) is a gut microbial metabolite of ellagic acid that has demonstrated neuroprotective effects in multiple neurological disease models. Nonetheless, the neuromodulatory role of UA in schizophrenia is yet to be elucidated. Wistar rat pups were separated from their mothers for 24 h on postnatal days (PNDs) 9-10 to establish an early-life stress model. The pups were pretreated with UA at different administration times (2, 4, and 6 weeks) and doses (50, 100, and 150 mg/kg) from adolescence (PND29). Behavioral tests were performed after the end of the administration. Subsequently, hippocampal samples were collected for histopathological and molecular evaluations. Male offspring rats subjected to maternal separation exhibited increased sensitivity to prepulse inhibition and cognitive impairment, accompanied by severe neuroinflammation and impaired neurogenesis. However, UA attenuated maternal separation-induced prepulse inhibition deficits and cognitive impairments and restored hippocampal neurogenesis in a dose-dependent manner. Furthermore, UA pretreatment preserved dendritic spine density, synapses, and presynaptic vesicles. In addition, it exerted anti-inflammatory effects by inhibiting microglial activation and expression of the proinflammatory cytokines tumor necrosis factor-α, interleukin-6, and interleukin-1β. Potential mechanisms included upregulation of brain-derived neurotrophic factor protein expression and activation of the extracellular signal-regulated kinase signaling pathway. This study is the first preclinical evaluation of the effects of UA on cognitive impairment in schizophrenia. The findings suggest that changes in cognitive function linked to schizophrenia are driven by the interaction among neuroinflammation, neurogenesis, and synaptic plasticity and that UA has the potential to reverse these processes. These observations provide evidence for future clinical trials of UA as a dietary supplement for preventing schizophrenia.

Fingolimod (FTY720), an antagonist of sphingosine-1-phosphate (S1P), functions by binding to S1P receptors (S1PRs), excluding S1PR2. It received approval from the Food and Drug Administration (FDA) for the treatment of multiple sclerosis (MS) in 2010. As the first non-selective oral agonist for S1PRs, FTY720's diverse and systemic receptor expression often leads to alterations in various signaling pathways and multiple systems, making it a subject of intense research. Recent studies have identified a wide range of novel or potential functions for FTY720 beyond its application in MS. These include effects on the blood-brain barrier (BBB), vascular system, organelles, and cell death, as well as potential applications in organ transplantation, immune disorders, oncological conditions, neurological and psychiatric disorders, viral infections, and hypersensitivity diseases. This paper reviews the novel roles, targets, and mechanisms of FTY720 that hold promise for clinical utility. Additionally, it summarizes FTY720's derivation and development process, the characterization and mechanism of the structure of FTY720-P bound to S1PRs, the clinical safety profile, future challenges, and potential strategies to address them. These insights aim to guide future research and applications of FTY720, maximizing its therapeutic potential.

The pathogenesis of cognitive impairment in schizophrenia (SCZ) remains unclear. Accumulating studies showed that inflammatory-immune dysregulation and altered brain derived neurotrophic factor (BDNF) levels play a crucial role in the psychopathology of SCZ. However, their association with cognitive dysfunction in first-episode SCZ patients has not been thoroughly investigated.

To explore the interaction effects between cognitive function and inflammatory cytokines and BDNF in first-episode SCZ.

The current study is a cross-sectional case-control investigation that recruited 84 patients with first-episode SCZ (SCZ group) and 80 healthy controls (HCs group) at the Huzhou Third Municipal Hospital between August 2021 and September 2023. ELISA was employed to measure the serum levels of interleukin (IL)-1β, IL-4, IL-6, IL-10, and BDNF. The Chinese brief cognitive test (C-BCT) and the positive and negative syndrome scales were measured the severity of cognitive impairment and psychiatric symptoms.

Compared to the HC group, the SCZ group exhibited elevated IL-1β and IL-6 levels, decreased BDNF levels, and reduced C-BCT scores (all P < 0.001). In SCZ, BDNF was negatively correlated with IL-6 (r = -0.324, P < 0.05). Information processing speed was negatively correlated with IL-6 (r = -0.315, P < 0.05) and positively with BDNF (r = 0.290, P < 0.05); attention, working memory, comprehensive ability, and executive function were negatively correlated with IL-1β and IL-6 (all P < 0.05) and positively with BDNF (all P < 0.05). Multiple regression analysis showed IL-6 influenced C-BCT dimensions (β = -0.218 to -0.327, all P < 0.05); attention and executive ability were influenced by IL-1β (β = -0.199 to -0.261, all P < 0.05); comprehensive executive ability was influenced by BDNF (β = 0.209, P < 0.05).

Our findings suggested that interrelationships between immune dysfunction and neurotrophic deficiency might underlie the pathological mechanisms of cognitive impairments in first-episode SCZ patients.

Chronic unpredictable and unavoidable stress is associated with mental health problems such as depression and anxiety, whereas cycles of stress and stress relief strengthen resilience. It has been suggested that increased breakdown of brain endocannabinoids (eCB) promotes a feeling of adversity. To assess the impact of stress on bioactive lipid homeostasis, we analyzed eCB, sphingolipids, and ceramides in seven brain regions and plasma in a mouse model of chronic unpredictable mild stress. Chronic unpredictable mild stress (CUMS) was associated with low levels of anandamide in hippocampus and prefrontal cortex in association with indicators of anxiety (elevated plus maze). Oppositely, CUMS caused elevated levels of sphingosine-1-phosphate (S1P d18:1) and sphinganine-1-phosphate (S1P d18:0) in the midbrain and thalamus, which was associated with readouts of increased stress resilience, i.e., marble burying and struggling in the tail suspension tests. In the periphery, elevated plasma levels of ceramides revealed similarities with human major depression and suggested unfavorable effects of stress on metabolism, but plasma lipids were not associated with body weight, sucrose consumption, or behavioral features of depression or anxiety. The observed brain site-specific lipid changes suggest that the forebrain succumbs to adverse stress effects while the midbrain takes up defensive adjustments.

Embedding methods have emerged as a valuable class of approaches for distilling essential information from complex high-dimensional data into more accessible lower-dimensional spaces. Applications of embedding methods to biological data have demonstrated that gene embeddings can effectively capture physical, structural, and functional relationships between genes. However, this utility has been primarily realized by using gene embeddings for downstream machine-learning tasks. Much less has been done to examine the embeddings directly, especially analyses of gene sets in embedding spaces. Here, we propose an Algorithm for Network Data Embedding and Similarity (ANDES), a novel best-match approach that can be used with existing gene embeddings to compare gene sets while reconciling gene set diversity. This intuitive method has important downstream implications for improving the utility of embedding spaces for various tasks. Specifically, we show how ANDES, when applied to different gene embeddings encoding protein-protein interactions, can be used as a novel overrepresentation- and rank-based gene set enrichment analysis method that achieves state-of-the-art performance. Additionally, ANDES can use multiorganism joint gene embeddings to facilitate functional knowledge transfer across organisms, allowing for phenotype mapping across model systems. Our flexible, straightforward best-match methodology can be extended to other embedding spaces with diverse community structures between set elements.

Neuropsychiatric and neurological disorders pose a significant global health burden, highlighting the need for innovative therapeutic approaches. Fingolimod (FTY720), a common drug to treat multiple sclerosis, has shown promising efficacy against various neuropsychiatric and neurological disorders. Fingolimod exerts its neuroprotective effects by targeting multiple cellular and molecular processes, such as apoptosis, oxidative stress, neuroinflammation, and autophagy. By modulating Sphingosine-1-Phosphate Receptor activity, a key regulator of immune cell trafficking and neuronal function, it also affects synaptic activity and strengthens memory formation. In the hippocampus, fingolimod decreases glutamate levels and increases GABA levels, suggesting a potential role in modulating synaptic transmission and neuronal excitability. Taken together, fingolimod has emerged as a promising neuroprotective agent for neuropsychiatric and neurological disorders. Its broad spectrum of cellular and molecular effects, including the modulation of apoptosis, oxidative stress, neuroinflammation, autophagy, and synaptic plasticity, provides a comprehensive therapeutic approach for these debilitating conditions. Further research is warranted to fully elucidate the mechanisms of action of fingolimod and optimize its use in the treatment of neuropsychiatric and neurological disorders.

The treatment of cognitive impairment in schizophrenia is an unaddressed need due to the absence of novel treatments. Recent studies demonstrated that fingolimod and siponimod have neuroprotective effects in several neuropsychiatric disorders; however, their pharmacological mechanisms are unclear. The objective of this study was to identify potential molecular mechanisms of fingolimod and siponimod for improving cognition of schizophrenia through network pharmacology and molecular docking. The putative target genes of ingredients, schizophrenia, and impaired cognition were obtained from online databases, including SwissTargetPrediction, PharmMapper, GeneCards, CTD, DisGeNET, and OMIM. A protein-protein interaction network was constructed to identify core targets. The DAVID database was used for GO and KEGG pathway enrichment analyses. An ingredient-target-pathway-disease network was constructed using Cytoscape. Finally, the interactions between ingredients and core targets were assessed with molecular docking. The analysis revealed 260 targets shared by fingolimod and siponimod, 257 unique targets for fingolimod, and 88 unique targets for siponimod. Two signaling pathways were involved in fingolimod-mediated improvements in the cognition of schizophrenia, including the PI3K-Akt and MAPK signaling pathways. The core targets that regulated these two pathways included IL1B, AKT1, TNF, IL6, INS, BCL2, and BDNF. The MAPK signaling pathway was involved in siponimod-mediated improvement in the cognition of schizophrenia. The MAPK pathway was regulated by three core targets, namely TNF, AKT1, and CASP3. Docking scores ranged from -5.0 to -10.4 kcal/mol. Our analysis revealed that fingolimod regulates the PI3K-Akt and MAPK signaling pathways via the core targets IL1B, AKT1, TNF, IL6, INS, BCL2, and BDNF, and siponimod regulates the MAPK signaling pathways via the core targets AKT1, TNF, and CASP3 to improve the cognition of schizophrenia. Our results provide potential targets and a theoretical basis for the design of new drugs to treat the impaired cognition of schizophrenia.

The small-molecule drug, FTY720 (fingolimod), is a synthetic sphingosine 1-phosphate (S1P) analogue currently used to treat relapsing-remitting multiple sclerosis in both adults and children. FTY720 can cross the blood-brain barrier (BBB) and, over time, accumulate in lipid-rich areas of the central nervous system (CNS) by incorporating into phospholipid membranes. FTY720 has been shown to enhance cell membrane fluidity, which can modulate the functions of glial cells and neuronal populations involved in regulating behaviour. Moreover, direct modulation of S1P receptor-mediated lipid signalling by FTY720 can impact homeostatic CNS physiology, including neurotransmitter release probability, the biophysical properties of synaptic membranes, ion channel and transmembrane receptor kinetics, and synaptic plasticity mechanisms. The aim of this study was to investigate how chronic FTY720 treatment alters the lipid composition of CNS tissue in adolescent mice at a key stage of brain maturation. We focused on the hippocampus, a brain region known to be important for learning, memory, and the processing of sensory and emotional stimuli. Using mass spectrometry-based lipidomics, we discovered that FTY720 increases the fatty acid chain length of hydroxy-phosphatidylcholine (PCOH) lipids in the mouse hippocampus. It also decreases PCOH monounsaturated fatty acids (MUFAs) and increases PCOH polyunsaturated fatty acids (PUFAs). A total of 99 lipid species were up-regulated in the mouse hippocampus following 3 weeks of oral FTY720 exposure, whereas only 3 lipid species were down-regulated. FTY720 also modulated anxiety-like behaviours in young mice but did not affect spatial learning or memory formation. Our study presents a comprehensive overview of the lipid classes and lipid species that are altered in the hippocampus following chronic FTY720 exposure and provides novel insight into cellular and molecular mechanisms that may underlie the therapeutic or adverse effects of FTY720 in the central nervous system.

We aimed to evaluate the potential of a novel selective α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) potentiator, LT-102, in treating cognitive impairments associated with schizophrenia (CIAS) and elucidating its mechanism of action.

The activity of LT-102 was examined by Ca2+ influx assays and patch-clamp in rat primary hippocampal neurons. The structure of the complex was determined by X-ray crystallography. The selectivity of LT-102 was evaluated by hERG tail current recording and kinase-inhibition assays. The electrophysiological characterization of LT-102 was characterized by patch-clamp recording in mouse hippocampal slices. The expression and phosphorylation levels of proteins were examined by Western blotting. Cognitive function was assessed using the Morris water maze and novel object recognition tests.

LT-102 is a novel and selective AMPAR potentiator with little agonistic effect, which binds to the allosteric site formed by the intradimer interface of AMPAR's GluA2 subunit. Treatment with LT-102 facilitated long-term potentiation in mouse hippocampal slices and reversed cognitive deficits in a phencyclidine-induced mouse model. Additionally, LT-102 treatment increased the protein level of brain-derived neurotrophic factor and the phosphorylation of GluA1 in primary neurons and hippocampal tissues.

We conclude that LT-102 ameliorates cognitive impairments in a phencyclidine-induced model of schizophrenia by enhancing synaptic function, which could make it a potential therapeutic candidate for CIAS.

This study was conducted to investigate the effects of long-term low-dose lithium adjunct to antipsychotic agent use on the cognitive performance, whole-brain gray-matter volume (GMV), and interleukin-6 (IL-6) level in drug-naive patients with first-episode schizophrenia, and to examine relationships among these factors. In this double-blind randomized controlled study, 50 drug-naive patients with first-episode schizophrenia each took low-dose (250 mg/day) lithium and placebo (of the same shape and taste) adjunct to antipsychotic agents (mean, 644.70 ± 105.58 and 677.00 ± 143.33 mg/day chlorpromazine equivalent, respectively) for 24 weeks. At baseline and after treatment completion, the MATRICS Consensus Cognitive Battery (MCCB) was used to assess cognitive performance, 3-T magnetic resonance imaging was performed to assess structural brain alterations, and serum IL-6 levels were quantified by immunoassay. Treatment effects were assessed within and between patient groups. Relationships among cognitive performance, whole-brain GMVs, and the IL-6 level were investigated by partial correlation analysis. Relative to baseline, patients in the lithium group showed improved working memory, verbal learning, processing speed, and reasoning/problem solving after 24 weeks of treatment; those in the placebo group showed only improved working memory and verbal learning. The composite MCCB score did not differ significantly between groups. The whole-brain GMV reduction was significantly lesser in the lithium group than in the placebo group (0.46% vs. 1.03%; P < 0.001). The GMV and IL-6 reduction ratios correlated with each other in both groups (r = -0.17, P = 0.025). In the lithium group, the whole-brain GMV reduction ratio correlated with the working memory improvement ratio (r = -0.15, P = 0.030) and processing speed (r = -0.14, P = 0.036); the IL-6 reduction ratio correlated with the working memory (r = -0.21, P = 0.043) and verbal learning (r = -0.30, P = 0.031) improvement ratios. In the placebo group, the whole-brain GMV reduction ratio correlated only with the working memory improvement ratio (r = -0.24, P = 0.019); the IL-6 reduction ratio correlated with the working memory (r = -0.17, P = 0.022) and verbal learning (r = -0.15, P = 0.011) improvement ratios. Both treatments implemented in this study nearly improved the cognitive performance of patients with schizophrenia; relative to placebo, low-dose lithium had slightly greater effects on several aspects of cognition. The patterns of correlation among GMV reduction, IL-6 reduction, and cognitive performance improvement differed between groups.

Comprehending the pathogenesis of schizophrenia represents a challenge for global mental health. To date, although it is evident that alterations in dopaminergic, serotonergic, and glutamatergic neurotransmission underlie the clinical expressiveness of the disease, neuronal disconnections represent only an epiphenomenon. In recent years, several clinical studies have converged on the hypothesis of microglia hyperactivation and a consequent neuroinflammatory state as a pathogenic substrate of schizophrenia. Prenatal, perinatal, and postnatal factors can cause microglia to switch from M2 anti-inflammatory to M1 pro-inflammatory states. A continuous mild neuroinflammatory state progressively leads to neuronal loss, a reduction in dendritic spines, and myelin degeneration. The augmentation of drugs that reduce neuroinflammation to antipsychotics could be an effective therapeutic modality in managing schizophrenia. This review will consider studies in which drugs with anti-inflammatory and neuroprotective properties have been used in addition to antipsychotic treatment in patients with schizophrenia.