Tumor necrosis factor receptor 1 is a negative regulator of progenitor proliferation in adult hippocampal neurogenesis

Controversies and insights into cytokine regulation of neurogenesis and behavior in adult rodents

Adult learning, memory, and social interaction partially depend on neurogenesis in two regions: the hippocampus and the subventricular zone. There is evidence that the immune system is important for these processes in pathological situations, but there is no review of its role in non-pathological or near-physiological conditions. Although further research is warranted in this area, some conclusions can be drawn. Intrusive LyC6hi monocytes and autoreactive CD4+ T cells have a positive impact on neurogenesis and behavior, but the latter are deleterious if specific to external antigens. Mildly activated microglia play a crucial role in promoting these processes, by eliminating apoptotic neuronal progenitors and producing low levels of interleukins, which increase if the cells are activated, leading to inhibition of neurogenesis. Chemokines are poorly studied, but progenitor cells and neurons express their receptors, which appear important for migration and maturation. The few works that jointly analyzed neurogenesis and behavior showed congruent effects of immune cells and cytokines. In conclusion, the immune system components -mostly local- seem of utmost importance for the control of behavior under non-pathological conditions.

The immune regulatory mechanism of ketamine-induced psychiatric disorders: A new perspective on drug-induced psychiatric symptoms

Ketamine, a psychoactive substance strictly regulated by international drug conventions, is classified as a "new type drug" due to its excitatory, hallucinogenic, or inhibitory effects. The etiology of ketamine-induced psychiatric symptoms is multifaceted, with the immune regulatory mechanism being the most prominent among several explanatory theories. In recent years, the interaction between the immune system and nervous system have garnered significant attention in neuropsychiatric disorder research. Notably, the infiltration of peripheral lymphocytes into the central nervous system has emerged as an early hallmark of certain neuropsychiatric disorders. However, a notable gap exists in the current literature, regarding the immune regulatory mechanisms, specifically the peripheral immune alterations, associated with ketamine-induced psychiatric symptoms. To address this void, this article endeavors to provide a comprehensive overview of the pathophysiological processes implicated in psychiatric disorders or symptoms, encompassing those elicited by ketamine. This analysis delves into aspects such as nerve damage, alterations within the central immune system, and the regulation of the peripheral immune system. By emphasizing the intricate crosstalk between the peripheral immune system and the central nervous system, this study sheds light on their collaborative role in the onset and progression of psychiatric diseases or symptoms. This insight offers fresh perspectives on the underlying mechanisms, diagnosis and therapeutic strategies for mental disorders stemming from drug abuse.

Plasma proteomics in epilepsy: Network-based identification of proteins associated with seizures

PURPOSE

Identification of potential biomarkers of seizures.

METHODS

In this exploratory study, we quantified plasma protein intensities in 15 patients with recent seizures compared to 15 patients with long-standing seizure freedom. Using TMT-based proteomics we found fifty-one differentially expressed proteins.

RESULTS

Network analyses including co-expression networks and protein-protein interaction networks, using the STRING database, followed by network centrality and modularity analyses revealed 22 protein modules, with one module showing a significant association with seizures. The protein-protein interaction network centered around this module identified a subnetwork of 125 proteins, grouped into four clusters. Notably, one cluster (mainly enriching inflammatory pathways and Gene Ontology terms) demonstrated the highest enrichment of known epilepsy-related genes.

CONCLUSION

Overall, our network-based approach identified a protein module linked with seizures. The module contained known markers of epilepsy and inflammation. The results also demonstrate the potential of network analysis in discovering new biomarkers for improved epilepsy management.

A microglia-containing cerebral organoid model to study early life immune challenges

Prenatal infections and activation of the maternal immune system have been proposed to contribute to causing neurodevelopmental disorders (NDDs), chronic conditions often linked to brain abnormalities. Microglia are the resident immune cells of the brain and play a key role in neurodevelopment. Disruption of microglial functions can lead to brain abnormalities and increase the risk of developing NDDs. How the maternal as well as the fetal immune system affect human neurodevelopment and contribute to NDDs remains unclear. An important reason for this knowledge gap is the fact that the impact of exposure to prenatal risk factors has been challenging to study in the human context. Here, we characterized a model of cerebral organoids (CO) with integrated microglia (COiMg). These organoids express typical microglial markers and respond to inflammatory stimuli. The presence of microglia influences cerebral organoid development, including cell density and neural differentiation, and regulates the expression of several ciliated and mesenchymal cell markers. Moreover, COiMg and organoids without microglia show similar but also distinct responses to inflammatory stimuli. Additionally, IFN-γ induced significant transcriptional and structural changes in the cerebral organoids, that appear to be regulated by the presence of microglia. Specifically, interferon-gamma (IFN-γ) was found to alter the expression of genes linked to autism. This model provides a valuable tool to study how inflammatory perturbations and microglial presence affect neurodevelopmental processes.

The potential mechanism of mitochondrial homeostasis in postoperative neurocognitive disorders: an in-depth review

Postoperative neurocognitive disorders (PND) are the most common neurological disorders following surgery and anaesthesia before and within 12 months after surgery, with a high prevalence in the geriatric population. PND can severely deteriorate the quality of life of patients, especially among the elderly, mainly manifested as memory loss, attention, decline and language comprehension disorders, mostly in elderly patients, with an incidence as high as 31%. Previous studies have also raised the possibility of accelerated cognitive decline and underlying neuropathological processes associated with diseases that affect cognitive performance (e.g. Alzheimer's dementia) for reasons related to anaesthesia and surgery. Currently, most research on PND has focused on various molecular pathways, especially in the geriatric population. The various hypotheses that have been proposed regarding the mechanisms imply peripheral neuroinflammation, oxidative stress, mitochondrial homeostasis, synaptic function, autophagy disorder, blood-brain barrier dysfunction, the microbiota-gut-brain axis and lack of neurotrophic support. However, the underlying pathogenesis and molecular mechanisms of PND have not yet been uncovered. Recent research has focused on mitochondrial homeostasis. In this paper, we present a review of various studies to better understand and characterize the mechanisms of associated cognitive dysfunction. As the biochemical basis of PND becomes more clearly defined, future treatments based on mitochondrial homeostasis modulation can prove to be very promising.

Taurine Reverses Arsenic-Induced Inhibition of Hippocampal Neurogenesis and Depression-Like Behavior in Mice

Arsenic exposure results in damage to the neurological system. We previously demonstrated the arsenic-induced inhibition of hippocampal neurogenesis and its reversibility after exposure is terminated. The present study aimed to reveal whether arsenic-induced inhibition of hippocampal neurogenesis was ameliorated when taurine was co-administered, and we also investigated depression-like behavioral changes using the forced swim test. Mice were randomly divided into four groups. The first group received distilled water only for 4 months (control group), the second group received 4.0 mg/L As2O3 via drinking water for 4 months (arsenic group), the third group received 4.0 mg/L As2O3 and taurine (150 mg/kg body weight, by gavage, twice a week) for 4 months (arsenic + taurine group), and the fourth group received taurine only by gavage for 4 months (taurine group). The percentage of new mature neurons decreased in the arsenic group compared with the control group (64% ± 0.90% vs. 76% ± 1.9%, p < 0.01); however, this percentage was reversed to control levels in the arsenic + taurine group (76% ± 1.4%, p > 0.05). In the forced swim test, the immobility time during the last 4 min was significantly increased in the arsenic group, but restored to control levels in the arsenic + taurine group. The possible mechanisms of this taurine amelioration of hippocampal damage were further investigated, and included a reduction in oxidative stress as indicated by carbonyl content, inflammation, and aquaporin1, 4, and 8 expressions, as well as an increase in Wnt3a and brain-derived neurotrophic factor expression in western blot analyses.

Recent advances in the synthesis of antidepressant derivatives: pharmacologic insights for mood disorders

Mood disorders, including depression, remain a significant global health concern, necessitating continuous efforts to develop novel and more effective antidepressant therapies. Although there have been significant advancements in comprehending the biology of Major Depressive Disorder (MDD), a considerable number of people suffering from depression do not exhibit positive responses to the pharmacologic treatments now available. This study specifically examines emerging targets and potential future approaches for pharmaceutical interventions in the treatment of MDD. The discussion revolves around novel therapeutic agents and their effectiveness in treating depression. The focus is on the specific pathophysiological pathways targeted by these agents and the amount of evidence supporting their use. While conventional antidepressants are anticipated to continue being the primary treatment for MDD in the foreseeable future, there is currently extensive research being conducted on numerous new compounds to determine their effectiveness in treating MDD. Many of these compounds have shown encouraging results. This review highlighted the recent advances in the synthesis of antidepressant derivatives and explores their pharmacologic insights for the treatment of mood disorders.

Decoding paradoxical links of cytokine markers in cognition: Cross talk between physiology, inflammaging, and Alzheimer's disease- related cognitive decline

Recent research has revolutionized our understanding of memory consolidation by emphasizing the critical role of astrocytes, microglia, and immune cells in through cytokine signaling. Cytokines, compact proteins, play pivotal roles in neuronal development, synaptic transmission, and normal aging. This review explores the cellular mechanisms contributing to cognitive decline in inflammaging and Alzheimer's disease, highlighting the paradoxical effects of most studied cytokines (IL-1, IL-6, TNF-α) in brain function, which act as a double-edged sword in brain physiology, acting both as facilitators of healthy cognitive function and as a potential contributor to cognitive decline.

Exploring the molecular targets of fingolimod and siponimod for treating the impaired cognition of schizophrenia using network pharmacology and molecular docking

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.

Human microglia-derived proinflammatory cytokines facilitate human retinal ganglion cell development and regeneration

Microglia (μG), the resident immune cells in the central nervous system, surveil the parenchyma to maintain the structural and functional homeostasis of neurons. Besides, they influence neurogenesis and synaptogenesis through complement-mediated phagocytosis. Emerging evidence suggests that μG may also influence development through proinflammatory cytokines. Here, we examined the premise that tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β), the two most prominent components of the μG secretome, influence retinal development, specifically the morphological and functional differentiation of human retinal ganglion cells (hRGCs). Using controlled generation of hRGCs and human μG (hμG) from pluripotent stem cells, we demonstrate that TNF-α and IL-1β secreted by unchallenged hμG did not influence hRGC generation. However, their presence significantly facilitated neuritogenesis along with the basal function of hRGCs, which involved the recruitment of the AKT/mTOR pathway. We present ex vivo evidence that proinflammatory cytokines may play an important role in the morphological and physiological maturation of hRGCs, which may be recapitulated for regeneration.

A microglia-containing cerebral organoid model to study early life immune challenges

Prenatal infections and activation of the maternal immune system have been proposed to contribute to causing neurodevelopmental disorders (NDDs), chronic conditions often linked to brain abnormalities. Microglia are the resident immune cells of the brain and play a key role in neurodevelopment. Disruption of microglial functions can lead to brain abnormalities and increase the risk of developing NDDs. How the maternal as well as the fetal immune system affect human neurodevelopment and contribute to NDDs remains unclear. An important reason for this knowledge gap is the fact that the impact of exposure to prenatal risk factors has been challenging to study in the human context. Here, we characterized a model of cerebral organoids (CO) with integrated microglia (COiMg). These organoids express typical microglial markers and respond to inflammatory stimuli. The presence of microglia influences cerebral organoid development, including cell density and neural differentiation, and regulates the expression of several ciliated mesenchymal cell markers. Moreover, COiMg and organoids without microglia show similar but also distinct responses to inflammatory stimuli. Additionally, IFN-γ induced significant transcriptional and structural changes in the cerebral organoids, that appear to be regulated by the presence of microglia. Specifically, interferon-gamma (IFN-γ) was found to alter the expression of genes linked to autism. This model provides a valuable tool to study how inflammatory perturbations and microglial presence affect neurodevelopmental processes.

Creatine supplementation increases postnatal growth and strength and prevents overexpression of pro-inflammatory interleukin 6 in the hippocampus in an experimental model of cerebral palsy

ABSTRACTObjectives: The aim of this study was thus to evaluate the effect of Cr supplementation on morphological changes and expression of pro-inflammatory cytokines in the hippocampus and on developmental parameters. Methods: Male Wistar rat pups were submitted to an experimental model of CP. Cr was administered via gavage from the 21st to the 28th postnatal day, and in water after the 28th, until the end of the experiment. Body weight (BW), food consumption (FC), muscle strength, and locomotion were evaluated. Expression of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) were assessed in the hippocampus by quantitative real-time polymerase chain reaction. Iba1 immunoreactivity was assessed by immunocytochemistry in the hippocampal hilus. Results: Experimental CP caused increased density and activation of microglial cells, and overexpression of IL-6. The rats with CP also presented abnormal BW development and impairment of strength and locomotion. Cr supplementation was able to reverse the overexpression of IL-6 in the hippocampus and mitigate the impairments observed in BW, strength, and locomotion. Discussion: Future studies should evaluate other neurobiological characteristics, including changes in neural precursor cells and other cytokines, both pro- and anti-inflammatory.

Exploring Zika Virus Impact on Endothelial Permeability: Insights into Transcytosis Mechanisms and Vascular Leakage

Treating brain disease is challenging, and the Zika virus (ZIKV) presents a unique obstacle due to its neuroinvasive nature. In this review, we discuss the immunopathogenesis of ZIKV and explore how the virus interacts with the body's immune responses and the role of the protein Mfsd2a in maintaining the integrity of the blood-brain barrier (BBB) during ZIKV neuroinvasion. ZIKV has emerged as a significant public health concern due to its association with severe neurological problems, including microcephaly and Gillain-Barré Syndrome (GBS). Understanding its journey through the brain-particularly its interaction with the placenta and BBB-is crucial. The placenta, which is designed to protect the fetus, becomes a pathway for ZIKV when infected. The BBB is composed of brain endothelial cells, acts as a second barrier, and protects the fetal brain. However, ZIKV finds ways to disrupt these barriers, leading to potential damage. This study explores the mechanisms by which ZIKV enters the CNS and highlights the role of transcytosis, which allows the virus to move through the cells without significantly disrupting the BBB. Although the exact mechanisms of transcytosis are unclear, research suggests that ZIKV may utilize this pathway.

The strong inverse association between plasma concentrations of soluble tumor necrosis factor receptors type 1 with adiponectin/leptin ratio in older women

Complex inflammatory crosstalk between muscular and adipose organs during ageing is controlled by adipokines and myokines. The Adiponectin/Leptin ratio (A/L ratio) has proven to be a promising biomarker for identifying insulin sensitivity, cardiovascular risk and adipose tissue inflammation. Although the A/L ratio has been related to inflammatory conditions, its ability to associate with or indicate the behavior of other inflammatory mediators remains unknown. The present study aimed to verify the association between the A/L ratio and a panel of inflammatory biomarkers in community-dwelling older women. The plasmatic concentrations of adiponectin, leptin, resistin, brain-derived neurotrophic factor (BDNF), interferon-gamma (IFN-γ), interleukins 2, 4, 5, 6, 8 and 10, tumour necrosis factor (TNF) and its soluble receptors (sTNF-r) 1 and 2 were evaluated in 71 community-dwelling older women with 75 (±7) years. The A/L ratio was negative and inverse correlated with BNDF (r = -0.29; p = 0.01), IL-8 (r = -0.37; p = 0.001) and sTNFr- 1 (r = -0.98; p < 0.001) levels. A strong and inverse association, with proportional effect, between A/L ratio and sTNFr-1 concentrations was found (Adjusted R2 = 0.22; β = -0.48; p > 0.001). It suggests that the presence of sTNFr-1 causes an inflammatory effect that affect cross-talk between muscle and adipose tissue, contributing to pro-inflammatory imbalance, which may have molecular and functional consequences. In addition, we provide insights into diagnostic biomarkers for inflammation, especially related to muscle wasting and intrinsic capacity in older people.

Sex specific effects of buprenorphine on adult hippocampal neurogenesis and behavioral outcomes during the acute phase after pediatric traumatic brain injury in mice

Traumatic brain injury (TBI) in children often causes cognitive and mental dysfunctions, as well as acute and chronic pain. Adult hippocampal neurogenesis plays a key role in cognition, depression, and pain. Adult hippocampal neurogenesis can be modulated by genetic and environmental factors, such as TBI and opioids. Buprenorphine (BPN), a semisynthetic opioid, is commonly used for pain management in children, however, the effects of BPN on adult hippocampal neurogenesis after pediatric TBI are still unclear. This study investigated the sex-specific effects of BPN on adult hippocampal neurogenesis during acute phase after pediatric TBI. Male and female littermates were randomized on postnatal day 20-21(P20-21) into Sham, TBI+saline and TBI+BPN groups. BPN was administered intraperitoneally to the TBI+BPN mice at 30 min after injury, and then every 6-12 h (h) for 2 days (d). Bromodeoxyuridine (BrdU) was administered intraperitoneally to all groups at 2, 4, 6, and 8-h post-injury. All outcomes were evaluated at 3-d post-BrdU administration. We found that TBI induced significant cognitive impairment, depression, and reduced adult hippocampal neurogenesis in both male and female mice, with more prominent effects in females. BPN significantly improved adult hippocampal neurogenesis and depression in males, but not in females. We further demonstrated that differential expressions of opioid receptors, transcription factors and neuroinflammatory markers at the neurogenic niche might be responsible for the differential effects of BPN in males and females. In conclusion, this study elucidates the effects of BPN on adult hippocampal neurogenesis and behavioral outcomes at the acute phase after pediatric TBI.

Exercise training improves long-term memory in obese mice

Obesity has been linked to a range of pathologies, including dementia. In contrast, regular physical activity is associated with the prevention or reduced progression of neurodegeneration. Specifically, physical activity can improve memory and spatial cognition, reduce age-related cognitive decline, and preserve brain volume, but the mechanisms are not fully understood. Accordingly, we investigated whether any detrimental effects of high-fat diet (HFD)-induced obesity on cognition, motor behavior, adult hippocampal neurogenesis, and brain-derived neurotrophic factor (BDNF) could be mitigated by voluntary exercise training in male C57Bl/6 mice. HFD-induced impairment of motor function was not reversed by exercise. Importantly, voluntary wheel running improved long-term memory and increased hippocampal neurogenesis, suggesting that regular physical activity may prevent cognitive decline in obesity.

Prediction and Validation of Hub Genes Related to Major Depressive Disorder Based on Co-expression Network Analysis

Major depressive disorder (MDD) is generally among the most prevalent psychiatric illnesses. Significant advances have occurred in comprehension of the MDD biology. However, it is still essential to recognize new biomarkers for potential targeted treatment of patients with MDD. The present work deals with in-depth comparative computational analyses to obtain new insights, such as gene ontology and pathway enrichment analyses and weighted gene co-expression network analysis (WGCNA) through gene expression dataset. The expression of selected hub-genes was validated in MDD patients using quantitative real-time PCR (RT-qPCR). We found that MDD progression includes the turquoise module genes (p-value = 1e-18, r = 0.97). According to gene enrichment analysis, the cytokine-mediated signaling pathway mostly involves genes in this module. By selection of four candidate hub-genes (IL6, NRG1, TNF, and BDNF), RT-qPCR validation was performed. A significant NRG1 downregulation was revealed by the RT-qPCR outcomes in MDD. In MDD patients, TNF and IL6 expression were considerably higher, and no considerable differences were found in the BDNF expression. Ultimately, based on ROC analyses, IL6, NRG1, and TNF had a higher MDD diagnostic performance. Therefore, our study presents information on the intricate association between MDD development and cytokine-mediated signaling, thus providing new rationales to develop new therapeutic approaches.

Neutrophil gelatinase-associated lipocalin (NGAL) and inflammatory markers in schizophrenia: A comparative analysis of drug-naive schizophrenia patients, remitted patients, and healthy controls

This study aims to examine the plasma concentrations of NGAL and other inflammatory parameters, including TNF-α, IL-1β, and IFN-γ, in schizophrenia patients and healthy volunteers. It also investigates potential associations between these biomarkers and symptom severity in schizophrenia and the utility of NGAL as a potential diagnostic and monitoring biomarker for schizophrenia. The study included 49 drug-naive schizophrenia patients (DNS), 59 patients with schizophrenia in remission (REM) on antipsychotic treatment, and 58 healthy volunteers (HC). The Positive and Negative Symptoms Evaluation Scale (PANSS) was utilized to assess the severity of symptoms in schizophrenia patients. Plasma levels of TNF-α, IL-1β, IFN-γ, and NGAL were measured for all participants. NGAL levels were significantly lower in the DNS group than in HC. Significantly lower TNF-α levels were observed in both the DNS and REM groups compared to the HC group. Notably, a statistically significant positive correlation was detected between TNF-α and NGAL levels. The findings of this study are noteworthy, as they demonstrate that drug-naive individuals with schizophrenia exhibit significantly diminished levels of NGAL and TNF-α compared to healthy controls. These identified biomarkers hold promise for providing valuable insights into the complex and evolving pathophysiology of schizophrenia.

Microglial depletion after brain injury prolongs inflammation and impairs brain repair, adult neurogenesis and pro-regenerative signaling

The adult zebrafish brain, unlike mammals, has a remarkable regenerative capacity. Although inflammation in part hinders regeneration in mammals, it is necessary for zebrafish brain repair. Microglia are resident brain immune cells that regulate the inflammatory response. To explore the microglial role in repair, we used liposomal clodronate or colony stimulating factor-1 receptor (csf1r) inhibitor to suppress microglia after brain injury, and also examined regeneration in two genetic mutant lines that lack microglia. We found that microglial ablation impaired telencephalic regeneration after injury. Microglial suppression attenuated cell proliferation at the intermediate progenitor cell amplification stage of neurogenesis. Notably, the loss of microglia impaired phospho-Stat3 (signal transducer and activator of transcription 3) and ß-Catenin signaling after injury. Furthermore, the ectopic activation of Stat3 and ß-Catenin rescued neurogenesis defects caused by microglial loss. Microglial suppression also prolonged the post-injury inflammatory phase characterized by neutrophil accumulation, likely hindering the resolution of inflammation. These findings reveal specific roles of microglia and inflammatory signaling during zebrafish telencephalic regeneration that should advance strategies to improve mammalian brain repair.

Autocrine positive feedback of tumor necrosis factor from activated microglia proposed to be of widespread relevance in chronic neurological disease

Over a decade's experience of post-stroke rehabilitation by administering the specific anti-TNF biological, etanercept, by the novel perispinal route, is consistent with a wide range of chronically diminished neurological function having been caused by persistent excessive cerebral levels of TNF. We propose that this TNF persistence, and cerebral disease chronicity, largely arises from a positive autocrine feedback loop of this cytokine, allowing the persistence of microglial activation caused by the excess TNF that these cells produce. It appears that many of these observations have never been exploited to construct a broad understanding and treatment of certain chronic, yet reversible, neurological illnesses. We propose that this treatment allows these chronically activated microglia to revert to their normal quiescent state, rather than simply neutralizing the direct harmful effects of this cytokine after its release from microglia. Logically, this also applies to the chronic cerebral aspects of various other neurological conditions characterized by activated microglia. These include long COVID, Lyme disease, post-stroke syndromes, traumatic brain injury, chronic traumatic encephalopathy, post-chemotherapy, post-irradiation cerebral dysfunction, cerebral palsy, fetal alcohol syndrome, hepatic encephalopathy, the antinociceptive state of morphine tolerance, and neurogenic pain. In addition, certain psychiatric states, in isolation or as sequelae of infectious diseases such as Lyme disease and long COVID, are candidates for being understood through this approach and treated accordingly. Perispinal etanercept provides the prospect of being able to treat various chronic central nervous system illnesses, whether they are of infectious or non-infectious origin, through reversing excess TNF generation by microglia.

Motor deficits are associated with increased glial cell activation in the hypothalamus and cerebellum of young rats subjected to cerebral palsy

Cerebral palsy (CP) is a syndrome characterized by a wide range of sensory and motor damage, associated with behavioral and cognitive deficits. The aim of the present study was to investigate the potential of a model of CP using a combination of perinatal anoxia and sensorimotor restriction of hind paws to replicate motor, behavioral and neural deficits. A total of 30 of male Wistar rats were divided into Control (C, n = 15), and CP (CP, n = 15) groups. The potential of the CP model was assessed by evaluating food intake, the behavioral satiety sequence, performance on the CatWalk and parallel bars, muscle strength, and locomotor activity. The weight of the encephalon, soleus, and extensor digitorum longus (EDL) muscles, and the activation of glial cells (microglia and astrocytes) were also measured. The CP animals showed delayed satiety, impaired locomotion on the CatWalk and open field test, reduced muscle strength, and reduced motor coordination. CP also reduced the weight of the soleus and muscles, brain weight, liver weight, and quantity of fat in various parts of the body. There was also found to be an increase in astrocyte and microglia activation in the cerebellum and hypothalamus (arcuate nucleus, ARC) of animals subjected to CP.

Advances in the study of the molecular biological mechanisms of radiation-induced brain injury

Radiation therapy is one of the most commonly used treatments for head and neck cancers, but it often leads to radiation-induced brain injury. Patients with radiation-induced brain injury have a poorer quality of life, and no effective treatments are available. The pathogenesis of this condition is unknown. This review summarizes the molecular biological mechanism of radiation-induced brain injury and provides research directions for future studies. The molecular mechanisms of radiation-induced brain injury are diverse and complex. Radiation-induced chronic neuroinflammation, destruction of the blood-brain barrier, oxidative stress, neuronal damage, and physiopathological responses caused by specific exosome secretion lead to radiation-induced brain injury.

The Implications of Cannabinoid-Induced Metabolic Dysregulation for Cellular Differentiation and Growth

The endocannabinoid system (ECS) governs and coordinates several physiological processes through an integrated signaling network, which is responsible for inducing appropriate intracellular metabolic signaling cascades in response to (endo)cannabinoid stimulation. This intricate cellular system ensures the proper functioning of the immune, reproductive, and nervous systems and is involved in the regulation of appetite, memory, metabolism, and development. Cannabinoid receptors have been observed on both cellular and mitochondrial membranes in several tissues and are stimulated by various classes of cannabinoids, rendering the ECS highly versatile. In the context of growth and development, emerging evidence suggests a crucial role for the ECS in cellular growth and differentiation. Indeed, cannabinoids have the potential to disrupt key energy-sensing metabolic signaling pathways requiring mitochondrial-ER crosstalk, whose functioning is essential for successful cellular growth and differentiation. This review aims to explore the extent of cannabinoid-induced cellular dysregulation and its implications for cellular differentiation.

Detrimental Effects of Alcohol-Induced Inflammation on Brain Health: From Neurogenesis to Neurodegeneration

Alcohol consumption is known to cause several brain anomalies. The pathophysiological changes associated with alcohol intoxication are mediated by various factors, most notable being inflammation. Alcohol intoxication may cause inflammation through several molecular mechanisms in multiple organs, including the brain, liver and gut. Alcohol-induced inflammation in the brain and gut are intricately connected. In the gut, alcohol consumption leads to the weakening of the intestinal barrier, resulting in bacteria and bacterial endotoxins permeating into the bloodstream. These bacterial endotoxins can infiltrate other organs, including the brain, where they cause cognitive dysfunction and neuroinflammation. Alcohol can also directly affect the brain by activating immune cells such as microglia, triggering the release of pro-inflammatory cytokines and neuroinflammation. Since alcohol causes the death of neural cells, it has been correlated to an increased risk of neurodegenerative diseases. Besides, alcohol intoxication has also negatively affected neural stem cells, affecting adult neurogenesis and causing hippocampal dysfunctions. This review provides an overview of alcohol-induced brain anomalies and how inflammation plays a crucial mechanistic role in alcohol-associated pathophysiology.

Effects of a six-month yoga intervention on the immune-inflammatory pathway in antipsychotic-stabilized schizophrenia patients: A randomized controlled trial

BACKGROUND

Schizophrenia is a complex neuropsychiatric disorder for which several etiopathological theories have been proposed, one of the prominent ones being immune dysfunction. Recent studies on yoga as an add-on therapy have shown improvement in negative symptoms, cognition, and quality of life in schizophrenia patients. However, the biological mechanism/s of action of yoga in schizophrenia are not clear. The current study was aimed at exploring the effects of long-term (6 months) add-on yoga therapy on the immune inflammatory pathway in schizophrenia patients.

METHODS

Sixty schizophrenia patients were randomized to add-on yoga therapy (YT=30) and treatment-as-usual (TAU=30) groups of which 21 patients in YT and 20 in TAU group completed the study. Blood samples and clinical assessments were obtained at baseline and at the end of 6 months. The plasma levels of nine cytokines (IL-2, IL-4, IL-5, IL-10, IL-12(p70), IL-13, GM-CSF, IFN-γ, and TNF-α) were quantified using multiplex suspension array. The clinical assessments included SAPS, SANS, BPRS, PSS, CGI, SOFS and WHOQUOL-BREF.

RESULTS

Patients in the yoga group showed significant reductions in plasma TNF-α (Z = 2.99, p = 0.003) and IL-5 levels (Z = 2.20, p = 0.03) and greater clinical improvements in SAPS, SANS, PSS, and SOFS scores as compared to TAU group. Further, plasma TNF-α levels exhibited a positive correlation with negative symptoms (r_s =0.45, p = 0.02) and socio-occupational functioning (r_s =0.61, p = 0.002) in the YT group.

CONCLUSIONS

The findings of the study suggest that improvements in schizophrenia psychopathology with yoga interventions are associated with immuno-modulatory effects.

Microglia activation mediates circadian rhythm disruption-induced cognitive impairment in mice

Alzheimer's disease (AD) is the leading cause of dementia and there are no effective treatments for this disease currently. Circadian rhythm disruption (CRD) is a hallmark of modern society that appears to be on the rise. It is well reported that AD is associated with disrupted circadian functioning and CRD can impair cognitive function. However, the cellular mechanisms underlying CRD-associated cognitive decline remain elusive. In this study, we investigated whether microglia are involved in CRD-induced cognitive decline. We established experimental 'jet lag' (phase delay of the light/dark cycles)-induced CRD mouse model and observed significant impairment of spatial learning and memory function in these mice. In the brain, CRD resulted in neuroinflammation, which was characterized by microglia activation and increased pro-inflammatory cytokine production, impairments in neurogenesis and reduction of synaptic proteins in the hippocampus. Interestingly, elimination of microglia with the colony stimulating factor-1 receptor inhibitor PLX3397 prevented CRD-induced neuroinflammation, cognitive decline, impairment of neurogenesis and loss of synaptic proteins. These findings collectively suggest that microglia activation plays a key role in CRD-induced cognitive deficit most likely through neuroinflammation-mediated impairments in adult neurogenesis and synapses.

The Role of Tumor Necrosis Factor Following Spinal Cord Injury: A Systematic Review

Pre-clinical studies place tumor necrosis factor (TNF) as a central player in the inflammatory response after spinal cord injury (SCI), and blocking its production and/or activity has been proposed as a possible treatment option after SCI. This systematic review provides an overview of the literature on the temporal and cellular expression of TNF after SCI and clarifies the potential for its therapeutic manipulation in SCI. A systematic search was performed in EMBASE (Ovid), MEDLINE (Ovid), and Web of Science (Core Collection). The search terms were the MeSH forms of tumor necrosis factor and spinal cord injury in the different databases, and the last search was performed on February 3, 2021. We found twenty-four articles examining the expression of TNF, with most using a thoracic contusive SCI model in rodents. Two articles described the expression of TNF receptors in the acute phase after SCI. Twenty-one articles described the manipulation of TNF signaling using genetic knock-out, pharmaceutical inhibition, or gain-of-function approaches. Overall, TNF expression increased rapidly after SCI, within the first hours, in resident cells (neurons, astrocytes, oligodendrocytes, and microglia) and again in macrophages in the chronic phase after injury. The review underscores the complexity of TNF's role after SCI and indicates that TNF inhibition is a promising therapeutic option. This review concludes that TNF plays a significant role in the inflammatory response after SCI and suggests that targeting TNF signaling is a feasible therapeutic approach.

Short-term administration of tibolone reduces inflammation and oxidative stress in the hippocampus of ovariectomized rats fed high-fat and high-fructose

Inflammation and oxidative stress are critical events involved in neurodegeneration. In animal models, it has been shown that chronic consumption of a hypercaloric diet, which leads to inflammatory processes, affects the hippocampus, a brain region fundamental for learning and memory processes. In addition, advanced age and menopause are risk factors for neurodegeneration. Hormone replacement therapy (HRT) ameliorates menopause symptoms. Tibolone (TB), a synthetic hormone, exerts estrogenic, progestogenic and androgenic effects on different tissues. We aimed to determine the effect of short-term TB administration on oxidative stress and inflammation markers in the hippocampus of ovariectomized rats fed a high-fat-and-fructose diet (HFFD). Adult female rats were ovariectomized (OVX) and fed standard diet or HFFD-consisting of 10% lard supplemented chow and 20% high-fructose syrup in the drinking water-and administered vehicle or TB (1 mg/kg for seven days). Finally, we administered hormone receptor antagonists (MPP, RU486 or FLU) to each of the OVX + HFFD + TB groups. Bodyweight, triglycerides and cholesterol, oxidative stress and inflammation markers, and the activity and expression of antioxidant enzymes were quantified in the hippocampus of each experimental group. We observed that short-term TB administration significantly reduced body weight, AGEs, MDA levels, increased SOD and GPx activity, improved GSH/GSSG ratio, and reduced IL-6 and TNF-α. Our findings suggest that short-term administration of TB decreases oxidative stress and reduces inflammation caused by HFFD and early estrogenic decline. These effects occurred via estrogen receptor alpha.

Associations between glutamic acid decarboxylase antibodies, oxidative stress markers, and cognitive capacity in adolescents who stutter

In this study, we amid to evaluate the correlation between the change in the expressed levels of anti-GAD antibodies titers, oxidative stress markers, cytokines markers, and cognitive capacity in adolescents with mild stuttering. Eighty participants (60 male/20 female) with the age range of 10-18 years with moderate stutteringparticipated in this study. To assess the stuttering and cognitive function, stutteringseverity instrument (SSI-4; 4th edit.)and the LOTCA-7 scores assessment were applied respectively in all subjects. In addition, serum GAD antibodies, cytokines like TNF-α, CRP,and IL-6 withtotal antioxidant capacity and nitric oxide as oxidative stress markers were estimated using calorimetry and immunoassay techniques.The results showed that good cognitive capacity was reported in about 56.25 % of the study population (n = 45) with a 117.52 ± 6.3 mean LOTCA-7 score. However, abnormal cognitive function was identified in 43.75 % of the study population (n = 35); they were categorized into moderate (score 62-92, n = 35), and poor (score 31-62; n = 10). There were significant associations between cognitive capacity reported and all biomarkers. The expression of GAD antibodies is significantly associated with the degree of cognitive capacity among students with stuttering. Significant association with the reduction (P = 0.01) in LOTCA-7 score domains, particularly orientation, thinking operations, attention, and concentration among students with variable cognitive capacity compared to controls. In addition, the expressed higher GAD antibodies in students with moderate and poor cognitive capacity showed to be significantly correlated with both elevated concentrations of cytokines; TNF-α, CRP, and IL-6, and the reduction of TAC and nitric oxide (NO) respectively. This study concludes that abnormality of cognitive capacity showed to be associated with higher expression of GAD antibodies, cytokines, and oxidative stress in school students with moderate stuttering.

Cellular plasticity and myeloid inflammation in the adult brain are independent of the transcriptional modulator DREAM

The downstream regulatory element antagonist modulator (DREAM) modulates ion channel function and gene transcription. Functionally, DREAM is implicated in physiological and pathological processes including cell proliferation, inflammation, and nociception. Despite its multiple functions and robust expression in forebrain tissue, neurons and glial cells, the role of DREAM in regard to cellular plasticity and tumor necrosis factor (TNF)-mediated inflammation is largely unexplored. Here, we demonstrate that adult hippocampal neurogenesis as well as the density and plasticity of glial cells in the hippocampus and thalamus are independent of the presence of DREAM. Further, DREAM deletion does not alter the regional myeloid response and inflammatory gene expression induced by chronic peripheral inflammation in mice overexpressing human TNF. Our data suggest that despite their highly dynamic regulation, neural cell plasticity and adult neurogenesis in the hippocampus do not depend on the multifunctional protein DREAM. Furthermore, TNF-mediated myeloid inflammation in the brain persists in the absence of DREAM.

The Dialogue Between Neuroinflammation and Adult Neurogenesis: Mechanisms Involved and Alterations in Neurological Diseases

Adult neurogenesis occurs mainly in the subgranular zone of the hippocampal dentate gyrus and the subventricular zone of the lateral ventricles. Evidence supports the critical role of adult neurogenesis in various conditions, including cognitive dysfunction, Alzheimer's disease (AD), and Parkinson's disease (PD). Several factors can alter adult neurogenesis, including genetic, epigenetic, age, physical activity, diet, sleep status, sex hormones, and central nervous system (CNS) disorders, exerting either pro-neurogenic or anti-neurogenic effects. Compelling evidence suggests that any insult or injury to the CNS, such as traumatic brain injury (TBI), infectious diseases, or neurodegenerative disorders, can provoke an inflammatory response in the CNS. This inflammation could either promote or inhibit neurogenesis, depending on various factors, such as chronicity and severity of the inflammation and underlying neurological disorders. Notably, neuroinflammation, driven by different immune components such as activated glia, cytokines, chemokines, and reactive oxygen species, can regulate every step of adult neurogenesis, including cell proliferation, differentiation, migration, survival of newborn neurons, maturation, synaptogenesis, and neuritogenesis. Therefore, this review aims to present recent findings regarding the effects of various components of the immune system on adult neurogenesis and to provide a better understanding of the role of neuroinflammation and neurogenesis in the context of neurological disorders, including AD, PD, ischemic stroke (IS), seizure/epilepsy, TBI, sleep deprivation, cognitive impairment, and anxiety- and depressive-like behaviors. For each disorder, some of the most recent therapeutic candidates, such as curcumin, ginseng, astragaloside, boswellic acids, andrographolide, caffeine, royal jelly, estrogen, metformin, and minocycline, have been discussed based on the available preclinical and clinical evidence.

Effect of Heat Stress on Hippocampal Neurogenesis: Insights into the Cellular and Molecular Basis of Neuroinflammation-Induced Deficits

Heat stress is known to result in neuroinflammation, neuronal damage, and disabilities in learning and memory in animals and humans. It has previously been reported that cognitive impairment caused by neuroinflammation may at least in part be mediated by defective hippocampal neurogenesis, and defective neurogenesis has been linked to aberrantly activated microglial cells. Moreover, the release of cytokines within the brain has been shown to contribute to the disruption of cognitive functions in several conditions following neuroinflammation. In this review, we summarize evolving evidence for the current understanding of inflammation-induced deficits in hippocampal neurogenesis, and the resulting behavioral impairments after heat stress. Furthermore, we provide valuable insights into the molecular and cellular mechanisms underlying neuroinflammation-induced deficits in hippocampal neurogenesis, particularly relating to cognitive dysfunction following heat stress. Lastly, we aim to identify potential mechanisms through which neuroinflammation induces cognitive dysfunction, and elucidate how neuroinflammation contributes to defective hippocampal neurogenesis. This review may therefore help to better understand the relationship between hippocampal neurogenesis and heat stress.

Stem Cells and Targeted Gene Therapy in Brain and Spinal Cord Tumors

The CNS tumors, in particular those with malignant characteristics, are prominent burdens around the world with high mortality and low cure rate. Given that, researchers were curious about novel treatments with promising effectiveness which resulted in shifting the dogmatism era of neurogenesis to the current concept of postnatal neurogenesis. Considering all existing stem cells, various strategies are available for treating CNS cancers, including hematopoietic stem cells transplantation, mesenchymal stem cells transplantation, neural stem cells (NSCs) transplantation, and using stem cells as genetic carriers called "suicide gene therapy". Despite some complications, this ongoing therapeutic method has succeeded in decreasing tumor volume, inhibiting tumor progression, and enhancing patients' survival. These approaches could lead to acceptable results, relatively better safety, and tolerable side effects compared to conventional chemo and radiotherapy. Accordingly, this treatment will be applicable to a wide range of CNS tumors in the near future. Furthermore, tumor genomic analysis and understanding of the underlying molecular mechanisms will help researchers determine patient selection criteria for targeted gene therapy.

The Molecular and Functional Changes of Neural Stem Cells in Alzheimer's Disease: Can They be Reinvigorated to Conduct Neurogenesis

Alzheimer's disease (AD) is considered one of the most complicated neurodegenerative disorders, and it is associated with progressive memory loss and remarkable neurocognitive dysfunction that negatively impacts the ability to perform daily living activities. AD accounts for an estimated 60-80% of dementia cases. AD's previously known pathological basis is the deposition of amyloid β (Aβ) aggregates and the formation of neurofibrillary tangles by tau hyperphosphorylation in the cell bodies of neurons that are located in the hippocampus, neocortex, and certain other regions of the cerebral hemispheres and limbic system. The lack of neurotransmitter acetylcholine and the activation of oxidative stress cascade may also contribute to the pathogenesis of AD. These pathological events can lead to irreversible loss of neuronal networks and the emergence of memory impairment and cognitive dysfunction that can engender an abnormal change in the personality. AD cannot be cured, and to some extent, the prescribed medications can only manage the symptoms associated with this disease. Several studies have reported that the regenerative abilities of neural stem/progenitor cells (NSCs) remarkably decline in AD, which disturbs the balancing power to control its progression. Exogenous infusion or endogenous activation of NSCs may be the ultimate solution to restore the neuronal networks in the brain of AD patients and regenerate the damaged areas responsible for memory and cognition. In this mini-review, we will touch upon the fate of NSCs in AD and the utilization of neurogenesis using modified NSCs to restore cognitive functions in AD.

The Gut-Immune-Brain Axis: An Important Route for Neuropsychiatric Morbidity in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) comprises Crohn's disease (CD) and ulcerative colitis (UC) and is associated with neuropsychiatric symptoms like anxiety and depression. Both conditions strongly worsen IBD disease burden. In the present review, we summarize the current understanding of the pathogenesis of depression and anxiety in IBD. We present a stepwise cascade along a gut-immune-brain axis initiated by evasion of chronic intestinal inflammation to pass the epithelial and vascular barrier in the gut and cause systemic inflammation. We then summarize different anatomical transmission routes of gut-derived peripheral inflammation into the central nervous system (CNS) and highlight the current knowledge on neuroinflammatory changes in the CNS of preclinical IBD mouse models with a focus on microglia, the brain-resident macrophages. Subsequently, we discuss how neuroinflammation in IBD can alter neuronal circuitry to trigger symptoms like depression and anxiety. Finally, the role of intestinal microbiota in the gut-immune-brain axis in IBD will be reviewed. A more comprehensive understanding of the interaction between the gastrointestinal tract, the immune system and the CNS accounting for the similarities and differences between UC and CD will pave the path for improved prediction and treatment of neuropsychiatric comorbidities in IBD and other inflammatory diseases.

Fatty Acid-Derived N-acylethanolamines Dietary Supplementation Attenuates Neuroinflammation and Cognitive Impairment in LPS Murine Model

Neuroinflammation plays a critical role in the pathogenesis of most neurological and neurodegenerative diseases and therefore represents a potential therapeutic target. In this regard, accelerating the resolution process in chronic neuroinflammation may be an effective strategy to deal with the cognitive consequences of neuropathology and generalized inflammatory processes. N-acylethanolamine (NAE) derivatives of fatty acids, being highly active lipid mediators, possess pro-resolving activity in inflammatory processes and are promising agents for the suppression of neuroinflammation and its consequences. This paper is devoted to a study of the effects played by dietary supplement (DS), containing a composition of fatty acid-derived NAEs, obtained from squid Berryteuthis magister, on the hippocampal neuroinflammatory and memory processes. By detecting the production of pro-inflammatory cytokines and glial markers, a pronounced anti-inflammatory activity of DS was demonstrated both in vitro and in vivo. DS administration reversed the LPS-induced reduction in hippocampal neurogenesis and memory deterioration. LC-MS analysis revealed an increase in the production of a range of NAEs with well-documented anti-inflammatory activity in response to the administered lipid composition. To conclude, we found that tested DS suppresses the neuroinflammatory response by reducing glial activation, positively regulates neural progenitor proliferation, and attenuates hippocampal-dependent memory impairment.

Pro-Inflammatory Profile of Children Exposed to Maternal Chikungunya Virus Infection during the Intrauterine Period: A One-Year Follow-Up Study

Chikungunya virus (CHIKV) vertical transmission occurs due to maternal viremia in the prepartum. Clinical presentation in neonates can be varied; however, the consequences of intrauterine exposure on the immune response are unclear. Thus, we aimed to analyze inflammatory alterations in children exposed to maternal CHIKV infection. This is a cross-sectional study that included children exposed to maternal CHIKV infection (confirmed by RT-qPCR and/or IgM). Circulant immune mediators were analyzed by a multiplex assay. RESULTS: We included 33 children, with a mean age of 3 ± 2.9 months-old, and 19 (57.6%) were male. Only one child presented neurological alterations. CHIKV-exposed infants showed elevated levels of MIP-1α, MIP-1β, and CCL-2 (p < 0.05). Pro-inflammatory cytokines such as TNFα, IL-6, and IL-7 (p < 0.0001) were also increased. In addition, lower levels of PDGF-BB and GM-CSF were observed in the same group (p < 0.0001). Principal component (PC) analysis highlighted a distinction in the inflammatory profile between groups, where PC explained 56.6% of the alterations. Our findings suggest that maternal exposure to CHIKV can affect the circulating levels of pro-inflammatory cytokines during the infants’ first year of life. The long-term clinical consequences of these findings should be investigated.

TNFα-Induced Oxidative Stress and Mitochondrial Dysfunction Alter Hypothalamic Neurogenesis and Promote Appetite Versus Satiety Neuropeptide Expression in Mice

Maternal obesity results in programmed offspring hyperphagia and obesity. The increased offspring food intake is due in part to the preferential differentiation of hypothalamic neuroprogenitor cells (NPCs) to orexigenic (AgRP) vs. anorexigenic (POMC) neurons. The altered neurogenesis may involve hypothalamic bHLH (basic helix–loop–helix) neuroregulatory factors (Hes1, Mash1, and Ngn3). Whilst the underlying mechanism remains unclear, it is known that mitochondrial function is critical for neurogenesis and is impacted by proinflammatory cytokines such as TNFα. Obesity is associated with the activation of inflammation and oxidative stress pathways. In obese pregnancies, increased levels of TNFα are seen in maternal and cord blood, indicating increased fetal exposure. As TNFα influences neurogenesis and mitochondrial function, we tested the effects of TNFα and reactive oxidative species (ROS) hydrogen peroxide (H₂O₂) on hypothalamic NPC cultures from newborn mice. TNFα treatment impaired NPC mitochondrial function, increased ROS production and NPC proliferation, and decreased the protein expression of proneurogenic Mash1/Ngn3. Consistent with this, AgRP protein expression was increased and POMC was decreased. Notably, treatment with H₂O₂ produced similar effects as TNFα and also reduced the protein expression of antioxidant SIRT1. The inhibition of STAT3/NFκB prevented the effects of TNFα, suggesting that TNFα mediates its effects on NPCs via mitochondrial-induced oxidative stress that involves both signaling pathways.

Multi-strain Probiotic Formulation Reverses Maternal Separation and Chronic Unpredictable Mild Stress-Generated Anxiety- and Depression-like Phenotypes by Modulating Gut Microbiome-Brain Activity in Rats

Depression is a debilitating mental disorder that affects >322 million people worldwide. Despite the availability of several antidepressant agents, many patients remain treatment refractory. A growing literature study has indicated the role of gut microbiota in neuropsychiatric disorders. Herein, we examined the psychobiotic-like activity of multi-strain probiotic formulation in maternal separation (MS) and chronic unpredictable mild stress (CUMS) models of anxiety- and depression-like phenotypes in Sprague-Dawley rats. Early- and late-life stress was employed in both male and female rats by exposing them to MS and CUMS. The multi-strain probiotic formulation (Cognisol) containing Bacillus coagulans Unique IS-2, Lactobacillus plantarum UBLP-40, Lactobacillus rhamnosus UBLR-58, Bifidobacterium lactis UBBLa-70, Bifidobacterium breve UBBr-01, and Bifidobacterium infantis UBBI-01 at a total strength of 10 billion cfu along with l-glutamine was administered for 6 weeks via drinking water. Neurobehavioral assessment was done using the forced swim test (FST), sucrose preference test (SPT), elevated plus maze (EPM), and open field test (OFT). Animals were sacrificed after behavioral assessment, and blood, brain, and intestine samples were collected to analyze the levels of cytokines, metabolites, and neurotransmitters and histology. Animals exposed to stress showed increased passivity, consumed less sucrose solution, and minimally explored the open arms in the FST, SPT, and EPM, respectively. Administration of multi-strain probiotics along with l-glutamine for 6 weeks ameliorated the behavioral abnormalities. The locomotor activity of animals in the OFT and their body weight remained unchanged across the groups. Cognisol treatment reversed the decreased BDNF and serotonin levels and increased CRP, TNF-α, and dopamine levels in the hippocampus and/or frontal cortex. Administration of Cognisol also restored the plasma levels of l-tryptophan, l-kynurenine, kynurenic-acid, and 3-hydroxyanthranilic acid; the Firmicutes-to-Bacteroides ratio; the levels of acetate, propionate, and butyrate in fecal samples; the villi/crypt ratio; and the goblet cell count, which manifested in the restoration of intestinal functions. We suggest that the multi-strain probiotic and glutamine formulation (Cognisol) ameliorated the MS + UCMS-generated anxiety- and depression-like phenotypes by reshaping the gut microbiome-brain activity in both sexes.

Neuroprotective Effect of Bcl-2 on Lipopolysaccharide-Induced Neuroinflammation in Cortical Neural Stem Cells

Neuroinflammation is involved in the pathogenesis of neurodegenerative diseases due to increased levels of pro-inflammatory cytokines in the central nervous system (CNS). Chronic neuroinflammation induced by neurotoxic molecules accelerates neuronal damage. B-cell lymphoma 2 (Bcl-2) is generally accepted to be an important anti-apoptotic factor. However, the role of Bcl-2 in neuroprotection against neuroinflammation remains to be determined. The purpose of this study was to investigate the neuroprotective effect of Bcl-2 on lipopolysaccharide (LPS)-induced neuroinflammation in cortical neural stem cells (NSCs). LPS decreased mRNA and protein levels of Tuj-1, a neuron marker, and also suppressed neurite outgrowth, indicating that LPS results in inhibition of neuronal differentiation of NSCs. Furthermore, LPS treatment inhibited Bcl-2 expression during neuronal differentiation; inhibition of neuronal differentiation by LPS was rescued by Bcl-2 overexpression. LPS-induced pro-inflammatory cytokines, including interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α), were decreased by Bcl-2 overexpression. Conversely, Bcl-2 siRNA increased the LPS-induced levels of IL-6 and TNF-α, and decreased neuronal differentiation of NSCs, raising the possibility that Bcl-2 mediates neuronal differentiation by inhibiting the LPS-induced inflammatory response in NSC. These results suggest that Bcl-2 has a neuroprotective effect by inhibiting the LPS-induced inflammatory response in NSCs.

Context-dependent effects of inflammation on retina regeneration

Inflammation is required for the proliferation of Müller glia (MG) into multipotent progenitors (MGPCs) in the injured fish and avian retinas. However, its function in retina regeneration has not been fully understood. Here we investigated the role of inflammation in three different retinal regeneration paradigms in zebrafish (stab-injury, NMDA-injury and insulin treatment). We first show that different types of immune cells and levels of inflammatory cytokines were found in the retinas of these paradigms. Though zymosan injection alone was insufficient to induce MG proliferation in the uninjured retina, immune suppression significantly inhibited MGPC formation in all three paradigms. Enhancing inflammation promoted MGPC formation after stab-injury, while exhibiting a context-dependent role in the NMDA or insulin models. We further show that proper levels of inflammation promoted MG reprogramming and cell cycle re-entry after stab- or NMDA-injury, but excessive inflammation also suppressed MG proliferation in the latter model. Finally, inflammation differentially affected neuronal regeneration in various injury paradigms. Our study reveals the complex and context-dependent role of inflammation during retinal repair in fish and suggests accurate inflammation management may be crucial for successful retina regeneration in mammals.

Zika Virus Neuropathogenesis: The Different Brain Cells, Host Factors and Mechanisms Involved

Zika virus (ZIKV), despite being discovered six decades earlier, became a major health concern only after an epidemic in French Polynesia and an increase in the number of microcephaly cases in Brazil. Substantial evidence has been found to support the link between ZIKV and neurological complications in infants. The virus targets various cells in the brain, including radial glial cells, neural progenitor cells (NPCs), astrocytes, microglial and glioblastoma stem cells. It affects the brain cells by exploiting different mechanisms, mainly through apoptosis and cell cycle dysregulation. The modulation of host immune response and the inflammatory process has also been demonstrated to play a critical role in ZIKV induced neurological complications. In addition to that, different ZIKV strains have exhibited specific neurotropism and unique molecular mechanisms. This review provides a comprehensive and up-to-date overview of ZIKV-induced neuroimmunopathogenesis by dissecting its main target cells in the brain, and the underlying cellular and molecular mechanisms. We highlighted the roles of the different ZIKV host factors and how they exploit specific host factors through various mechanisms. Overall, it covers key components for understanding the crosstalk between ZIKV and the brain.

Experimental Arthritis Inhibits Adult Hippocampal Neurogenesis in Mice

Background: Adult-born neurons of the hippocampal dentate gyrus play a role in specific forms of learning, and disturbed neurogenesis seems to contribute to the development of neuropsychiatric disorders, such as major depression. Neuroinflammation inhibits adult neurogenesis, but the effect of peripheral inflammation on this form of neuroplasticity is ambiguous. Objective: Our aim was to investigate the influence of acute and chronic experimental arthritis on adult hippocampal neurogenesis and to elucidate putative regulatory mechanisms. Methods: Arthritis was triggered by subcutaneous injection of complete Freund’s adjuvant (CFA) into the hind paws of adult male mice. The animals were killed either seven days (acute inflammation) or 21 days (chronic inflammation) after the CFA injection. Behavioral tests were used to demonstrate arthritis-related hypersensitivity to painful stimuli. We used in vivo bioluminescence imaging to verify local inflammation. The systemic inflammatory response was assessed by complete blood cell counts and by measurement of the cytokine/chemokine concentrations of TNF-α, IL-1α, IL-4, IL-6, IL-10, KC and MIP-2 in the inflamed hind limbs, peripheral blood and hippocampus to characterize the inflammatory responses in the periphery and in the brain. In the hippocampal dentate gyrus, the total number of newborn neurons was determined with quantitative immunohistochemistry visualizing BrdU- and doublecortin-positive cells. Microglial activation in the dentate gyrus was determined by quantifying the density of Iba1- and CD68-positive cells. Results: Both acute and chronic arthritis resulted in paw edema, mechanical and thermal hyperalgesia. We found phagocytic infiltration and increased levels of TNF-α, IL-4, IL-6, KC and MIP-2 in the inflamed hind paws. Circulating neutrophil granulocytes and IL-6 levels increased in the blood solely during the acute phase. In the dentate gyrus, chronic arthritis reduced the number of doublecortin-positive cells, and we found increased density of CD68-positive macrophages/microglia in both the acute and chronic phases. Cytokine levels, however, were not altered in the hippocampus. Conclusions: Our data suggest that acute peripheral inflammation initiates a cascade of molecular and cellular changes that eventually leads to reduced adult hippocampal neurogenesis, which was detectable only in the chronic inflammatory phase.

Ameliorating effect of continuous alpha-glycosyl isoquercitrin treatment starting from late gestation in a rat autism model induced by postnatal injection of lipopolysaccharides

The present study investigated the role of neuroinflammation and brain oxidative stress induced by neonatal treatment with lipopolysaccharides (LPS) on the development of autism spectrum disorder (ASD)-like behaviors and disruptive hippocampal neurogenesis in rats by exploring the chemopreventive effects of alpha-glycosyl isoquercitrin (AGIQ) as an antioxidant. AGIQ was dietary administered to dams at 0.25% or 0.5% (w/w) from gestational day 18 until postnatal day (PND) 21 on weaning and then to pups until the adult stage on PND 77. The pups were intraperitoneally injected with LPS (1 mg/kg body weight) on PND 3. At PND 6, LPS alone increased Iba1+ and CD68+ cell numbers without changing the CD163+ cell number and strongly upregulated pro-inflammatory cytokine gene expression (Il1a, Il1b, Il6, Nfkb1, and Tnf) in the hippocampus, and increased brain malondialdehyde levels. At PND 10, pups decreased ultrasonic vocalization (USV), suggesting the induction of pro-inflammatory responses and oxidative stress to trigger communicative deficits. By contrast, LPS alone upregulated Nfe2l2 expression at PND 6, increased Iba1+, CD68+, and CD163+ cell numbers, and upregulated Tgfb1 at PND 21, suggesting anti-inflammatory responses until the weaning period. However, LPS alone disrupted hippocampal neurogenesis at weaning and suppressed social interaction parameters and rate of freezing time at fear acquisition and extinction during the adolescent stage. On PND 77, neuroinflammatory responses had mostly disappeared; however, disruptive neurogenesis and fear memory deficits were sustained. AGIQ ameliorated most changes on acute pro-inflammatory responses and oxidative stress at PND 6, and the effects on USVs at PND 10 and neurogenesis and behavioral parameters throughout the adult stage. These results suggested that neonatal LPS treatment induced acute but transient neuroinflammation, triggering the progressive disruption of hippocampal neurogenesis leading to abnormal behaviors in later life. AGIQ treatment was effective for ameliorating LPS-induced progressive changes by critically suppressing initial pro-inflammatory responses and oxidative stress.

Neuroinflammation as an etiological trigger for depression comorbid with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) suffer from depression at higher rates than the general population. An etiological trigger of depressive symptoms is theorised to be inflammation within the central nervous system. It is believed that heightened intestinal inflammation and dysfunction of the enteric nervous system (ENS) contribute to impaired intestinal permeability, which facilitates the translocation of intestinal enterotoxins into the blood circulation. Consequently, these may compromise the immunological and physiological functioning of distant non-intestinal tissues such as the brain. In vivo models of colitis provide evidence of increased blood–brain barrier permeability and enhanced central nervous system (CNS) immune activity triggered by intestinal enterotoxins and blood-borne inflammatory mediators. Understanding the immunological, physiological, and structural changes associated with IBD and neuroinflammation may aid in the development of more tailored and suitable pharmaceutical treatment for IBD-associated depression.

Prior maternal separation stress alters the dendritic complexity of new hippocampal neurons and neuroinflammation in response to an inflammatory stressor in juvenile female rats

Stress during critical periods of neurodevelopment is associated with an increased risk of developing stress-related psychiatric disorders, which are more common in women than men. Hippocampal neurogenesis (the birth of new neurons) is vulnerable to maternal separation (MS) and inflammatory stressors, and emerging evidence suggests that hippocampal neurogenesis is more sensitive to stress in the ventral hippocampus (vHi) than in the dorsal hippocampus (dHi). Although research into the effects of MS stress on hippocampal neurogenesis is well documented in male rodents, the effect in females remains underexplored. Similarly, reports on the impact of inflammatory stressors on hippocampal neurogenesis in females are limited, especially when female bias in the prevalence of stress-related psychiatric disorders begins to emerge. Thus, in this study we investigated the effects of MS followed by an inflammatory stressor (lipopolysaccharide, LPS) in early adolescence on peripheral and hippocampal inflammatory responses and hippocampal neurogenesis in juvenile female rats. We show that MS enhanced an LPS-induced increase in the pro-inflammatory cytokine IL-1β in the vHi but not in the dHi. However, microglial activation was similar following LPS alone or MS alone in both hippocampal regions, while MS prior to LPS reduced microglial activation in both dHi and vHi. The production of new neurons was unaffected by MS and LPS. MS and LPS independently reduced the dendritic complexity of new neurons, and MS exacerbated LPS-induced reductions in the complexity of distal dendrites of new neurons in the vHi but not dHi. These data highlight that MS differentially primes the physiological response to LPS in the juvenile female rat hippocampus.

Spinal Cord Injury Leads to Hippocampal Glial Alterations and Neural Stem Cell Inactivation

The hippocampus encodes spatial and contextual information involved in memory and learning. The incorporation of new neurons into hippocampal networks increases neuroplasticity and enhances hippocampal-dependent learning performances. Only few studies have described hippocampal abnormalities after spinal cord injury (SCI) although cognitive deficits related to hippocampal function have been reported in rodents and even humans. The aim of this study was to characterize in further detail hippocampal changes in the acute and chronic SCI. Our data suggested that neurogenesis reduction in the acute phase after SCI could be due to enhanced death of amplifying neural progenitors (ANPs). In addition, astrocytes became reactive and microglial cells increased their number in almost all hippocampal regions studied. Glial changes resulted in a non-inflammatory response as the mRNAs of the major pro-inflammatory cytokines (IL-1β, TNFα, IL-18) remained unaltered, but CD200R mRNA levels were downregulated. Long-term after SCI, astrocytes remained reactive but on the other hand, microglial cell density decreased. Also, glial cells induced a neuroinflammatory environment with the upregulation of IL-1β, TNFα and IL-18 mRNA expression and the decrease of CD200R mRNA. Neurogenesis reduction may be ascribed at later time points to inactivation of neural stem cells (NSCs) and inhibition of ANP proliferation. The number of granular cells and CA1 pyramidal neurons decreased only in the chronic phase. The release of pro-inflammatory cytokines at the chronic phase might involve neurogenesis reduction and neurodegeneration of hippocampal neurons. Therefore, SCI led to hippocampal changes that could be implicated in cognitive deficits observed in rodents and humans.

Agonistic analog of growth hormone-releasing hormone promotes neurofunctional recovery and neural regeneration in ischemic stroke

Ischemic stroke can induce neurogenesis. However, most stroke-generated newborn neurons cannot survive. It has been shown that MR-409, a potent synthetic agonistic analog of growth hormone-releasing hormone (GHRH), can protect against some life-threatening pathological conditions by promoting cell proliferation and survival. The present study shows that long-term treatment with MR-409 (5 or 10 μg/mouse/d) by subcutaneous (s.c.) injection significantly reduces the mortality, ischemic insult, and hippocampal atrophy, and improves neurological functional recovery in mice operated on for transient middle cerebral artery occlusion (tMCAO). Besides, MR-409 can stimulate endogenous neurogenesis and improve the tMCAO-induced loss of neuroplasticity. MR-409 also enhances the proliferation and inhibits apoptosis of neural stem cells treated with oxygen and glucose deprivation-reperfusion. The neuroprotective effects of MR-409 are closely related to the activation of AKT/CREB and BDNF/TrkB pathways. In conclusion, the present study demonstrates that GHRH agonist MR-409 has remarkable neuroprotective effects through enhancing endogenous neurogenesis in cerebral ischemic mice.