Th17 and Cognitive Impairment: Possible Mechanisms of Action

The Effects of Sishen Wan on T Cell Responses in Mice Models of Ulcerative Colitis Induced by Dextran Sodium Sulfate

Currently, it is unclear whether Sishen Wan (SSW) could modulate the balance of Th1 cells, Th17 cells, and Tregs and we evaluated the effects of SSW on T cell responses in mice models of ulcerative colitis (UC). The mice models of acute UC (4% dextran sodium sulfate (DSS), 8 days) and chronic UC (3% DSS, 16 days) with SSW were assayed. Colon tissues were collected for immunohistochemical analysis, enzyme linked immunosorbent assay (ELISA), and flow cytometry (FCM). The expressions of cytokines associated with Tregs, transcription factors of Th17 cells, the frequencies of Th1 cells, Th17 cells, and Tregs, and the functional plasticity of Th17 cells were detected. The frequency of IFN-γ⁺ T cells was not changed significantly with SSW treatment in acute DSS. In chronic models, the frequency of IFN-γ⁺ T cells was downregulated with SSW. Meanwhile, the levels of RORγt and the frequency of IL-17A⁺ Th17 cells showed no significant differences after SSW treatment. Despite no significant effect on the transdifferentiation of Th17 cells in chronic UC models, SSW transdifferentiated Th17 cells into IL-10⁺ Th17 cells and downregulated IFN-γ⁺ Th17 cells/IL-10⁺ Th17 cells in acute DSS. Moreover, there were no significant changes of cytokines secreted by Tregs in acute DSS after SSW treatment, but SSW facilitated the expressions of IL-10 and IL-35, as well as development of IL-10⁺ Tregs in chronic DSS. SSW showed depressive effects on the immunoreaction of Th17 cells and might promote the conversion of Th17 cells into IL-10⁺ Th17 cells in acute UC, while it inhibited the excessive reaction of Th1 cells, facilitated the development of Tregs, and enhanced the anti-inflammatory effects in chronic UC.

Cancer-related cognitive impairment is associated with perturbations in inflammatory pathways

Cancer-related cognitive impairment (CRCI) is a significant problem for patients receiving chemotherapy. While a growing amount of pre-clinical and clinical evidence suggests that inflammatory mechanisms underlie CRCI, no clinical studies have evaluated for associations between CRCI and changes in gene expression. Therefore, the purpose of this study was to evaluate for differentially expressed genes and perturbed inflammatory pathways across two independent samples of patients with cancer who did and did not report CRCI. The Attentional Function Index (AFI) was the self-report measure used to assess CRCI. AFI scores of <5 and of >7.5 indicate low versus high levels of cognitive function, respectively. Of the 185 patients in Sample 1, 49.2% had an AFI score of <5 and 50.8% had an AFI score of >7.5. Of the 158 patients in Sample 2, 50.6% had an AFI score of <5 and 49.4% had an AFI score of >7.5. Data from 182 patients in Sample 1 were analyzed using RNA-seq. Data from 158 patients in Sample 2 were analyzed using microarray. Twelve KEGG signaling pathways were significantly perturbed between the AFI groups, five of which were signaling pathways related to inflammatory mechanisms (e.g., cytokine-cytokine receptor interaction, tumor necrosis factor signaling). This study is the first to describe perturbations in inflammatory pathways associated with CRCI. Findings highlight the role of cytokines both in terms of cytokine-specific pathways, as well as pathways involved in cytokine production and cytokine activation. These findings have the potential to identify new targets for therapeutics and lead to the development of interventions to improve cognition in patients with cancer.

Inflammation: A Mediator Between Hypertension and Neurodegenerative Diseases

Hypertension is the most prevalent and modifiable risk factor for stroke, vascular cognitive impairment, and Alzheimer's disease. However, the mechanistic link between hypertension and neurodegenerative diseases remains to be understood. Recent evidence indicates that inflammation is a common pathophysiological trait for both hypertension and neurodegenerative diseases. Low-grade chronic inflammation at the systemic and central nervous system levels is now recognized to contribute to the physiopathology of hypertension. This review speculates that inflammation represents a mediator between hypertension and neurodegenerative diseases, either by a decrease in cerebral blood flow or a disruption of the blood-brain barrier which will, in turn, let inflammatory cells and neurotoxic molecules enter the brain parenchyma. This may impact brain functions including cognition and contribute to neurodegenerative diseases. This review will thus discuss the relationship between hypertension, systemic inflammation, cerebrovascular functions, neuroinflammation, and brain dysfunctions. The potential clinical future of immunotherapies against hypertension and associated cerebrovascular risks will also be presented.

Neurofilament light: a possible prognostic biomarker for treatment of vascular contributions to cognitive impairment and dementia

Background

Decreased cerebral blood flow and systemic inflammation during heart failure (HF) increase the risk for vascular contributions to cognitive impairment and dementia (VCID) and Alzheimer disease-related dementias (ADRD). We previously demonstrated that PNA5, a novel glycosylated angiotensin 1–7 (Ang-(1–7)) Mas receptor (MasR) agonist peptide, is an effective therapy to rescue cognitive impairment in our preclinical model of VCID. Neurofilament light (NfL) protein concentration is correlated with cognitive impairment and elevated in neurodegenerative diseases, hypoxic brain injury, and cardiac disease. The goal of the present study was to determine (1) if treatment with Ang-(1–7)/MasR agonists can rescue cognitive impairment and decrease VCID-induced increases in NfL levels as compared to HF-saline treated mice and, (2) if NfL levels correlate with measures of cognitive function and brain cytokines in our VCID model.

Methods

VCID was induced in C57BL/6 male mice via myocardial infarction (MI). At 5 weeks post-MI, mice were treated with daily subcutaneous injections for 24 days, 5 weeks after MI, with PNA5 or angiotensin 1–7 (500 microg/kg/day or 50 microg/kg/day) or saline (n = 15/group). Following the 24-day treatment protocol, cognitive function was assessed using the Novel Object Recognition (NOR) test. Cardiac function was measured by echocardiography and plasma concentrations of NfL were quantified using a Quanterix Simoa assay. Brain and circulating cytokine levels were determined with a MILLIPLEX MAP Mouse High Sensitivity Multiplex Immunoassay. Treatment groups were compared via ANOVA, significance was set at p < 0.05.

Results

Treatment with Ang-(1–7)/MasR agonists reversed VCID-induced cognitive impairment and significantly decreased NfL levels in our mouse model of VCID as compared to HF-saline treated mice. Further, NfL levels were significantly negatively correlated with cognitive scores and the concentrations of multiple pleiotropic cytokines in the brain.

Conclusions

These data show that treatment with Ang-(1–7)/MasR agonists rescues cognitive impairment and decreases plasma NfL relative to HF-saline-treated animals in our VCID mouse model. Further, levels of NfL are significantly negatively correlated with cognitive function and with several brain cytokine concentrations. Based on these preclinical findings, we propose that circulating NfL might be a candidate for a prognostic biomarker for VCID and may also serve as a pharmacodynamic/response biomarker for therapeutic target engagement.

Bee venom acupuncture therapy ameliorates neuroinflammatory alterations in a pilocarpine-induced epilepticus model

Bee venom (BV) is applied in different traditional medicinal therapies and is used worldwide to prevent and treat many acute and chronic diseases. Epilepsy has various neurological effects, e.g., epileptogenic insults; thus, it is considered a life-threatening condition. Seizures and their effects add to the burden of epilepsy because they can have health effects including residual disability and even premature mortality. The use of antiinflammatory drugs to treat epilepsy is controversial; therefore, the alternative nonchemical apitherapy benefits of BV were evaluated in the present study by assessing neuroinflammatory changes in a pilocarpine-induced epilepticus model. Levels of electrolytes, neurotransmitters, and mRNA expression for some gate channels were determined. Moreover, ELISA assays were conducted to detect pro- and anti-inflammatory cytokines, whereas RT-PCR was performed to assess mRNA expression of Foxp3 and CTLA-4. BV ameliorated the interruption in electrolytes and ions through voltage- and ligand-gated ion channels, and it limited neuronal excitability via rapid repolarization of action potentials. In addition, BV inhibited the high expression of proinflammatory cytokines. Acupuncture with BV was effective in preventing some of the deleterious consequences of epileptogenesis associated with high levels of glutamate and DOPA in the hippocampus. BV ameliorates changes in the expression of voltage-gated channels, rebalances blood electrolytes and neurotransmitters, and modulates the levels of pro- and anti-inflammatory cytokines. Thus, BV could reduce the progression of epileptogenesis as a cotherapy with other antiepileptic drugs.

Asthma and posttraumatic stress disorder (PTSD): Emerging links, potential models and mechanisms

Posttraumatic stress disorder (PTSD) is a highly prevalent, debilitating mental health condition. A better understanding of contributory neurobiological mechanisms will lead to effective treatments, improving quality of life for patients. Given that not all trauma-exposed individuals develop PTSD, identification of pre-trauma susceptibility factors that can modulate posttraumatic outcomes is important. Recent clinical evidence supports a strong link between inflammatory conditions and PTSD. A particularly strong association has been reported between asthma and PTSD prevalence and severity. Unlike many other PTSD-comorbid inflammatory conditions, asthma often develops in children, sensitizing them to subsequent posttraumatic pathology throughout their lifetime. Currently, there is a significant need to understand the neurobiology, shared mechanisms, and inflammatory mediators that may contribute to comorbid asthma and PTSD. Here, we provide a translational perspective of asthma and PTSD risk and comorbidity, focusing on clinical associations, relevant rodent paradigms and potential mechanisms that may translate asthma-associated inflammation to PTSD development.

Circadian Clock Regulates Inflammation and the Development of Neurodegeneration

The circadian clock regulates numerous key physiological processes and maintains cellular, tissue, and systemic homeostasis. Disruption of circadian clock machinery influences key activities involved in immune response and brain function. Moreover, Immune activation has been closely linked to neurodegeneration. Here, we review the molecular clock machinery and the diurnal variation of immune activity. We summarize the circadian control of immunity in both central and peripheral immune cells, as well as the circadian regulation of brain cells that are implicated in neurodegeneration. We explore the important role of systemic inflammation on neurodegeneration. The circadian clock modulates cellular metabolism, which could be a mechanism underlying circadian control. We also discuss the circadian interventions implicated in inflammation and neurodegeneration. Targeting circadian clocks could be a potential strategy for the prevention and treatment of inflammation and neurodegenerative diseases.

Interleukin-17A in Alzheimer's disease: recent advances and controversies

Alzheimer’s disease (AD) is a progressive neurodegenerative disease that mainly affects older adults. Although the global burden of AD is increasing year by year, the causes of AD remain largely unknown. Numerous basic and clinical studies have shown that interleukin-17A (IL-17A) may play a significant role in the pathogenesis of AD. A comprehensive assessment of the role of IL-17A in AD would benefit the diagnosis, understanding of etiology and treatment. However, over the past decade, controversies remain regarding the expression level and role of IL-17A in AD. We have incorporated newly published researches and point out that IL-17A expression levels may vary along with the development of AD, exercising different roles at different stages of AD, although much more work remains to be done to support the potential role of IL-17A in AD-related pathology. Here, it is our intention to review the underlying mechanisms of IL-17A in AD and address the current controversies in an effort to clarify the results of existing research and suggest future studies.

Exposure to hypertonic solutions during pregnancy induces autism-like behaviors via the NFAT-5 pathway in offspring in a rat model

OBJECTIVES

to investigate the effects of hyperosmolar state (HS) on immune response and inflammation via the NFAT5 pathway and examine whether immune-mediated conditions trigger autism-like behavior in offspring.

METHODS

a pregnant rat model was performed by administering hyperosmotic solutions. Pregnant rats were divided into 2 main groups; control (group I) and hyperosmolar groups (group II). Control group rats were given % 0.25 NaCI (tap water) (n = 6), the Hyperosmolar (HO) group was further subdivided into 3 groups as; Group II a rats which were given % 3 hypertonic NaCl (n = 6), Group II b rats were given mineral water (% 3 NaHCO3+magnesium+calcium content) (n = 6), and Group II c rats were given Ayran (% 0.8 NaCl content) (n = 6). Their offspring were examined for behaviors, biochemical and histological abnormality.

RESULTS

in offspring, TNF- α, IL-17, NFAT-5, and NGF levels in the brain were significantly higher in hyperosmotic solution groups than in control rats. Exposure of pregnant rats to hyperosmotic solution resulted in autism-like behaviors in their offspring. Through immunohistochemical methods, we found that CA1 and CA2 of the hippocampus indicated decreased number of neurons in hyperosmotic solution groups compared with the control group.

CONCLUSIONS

our findings once again emphasized that the immune-mediated conditions involved in the pathophysiology of autism. NFAT5 pathway may be a key factor in the development of neuroinflammation by hyperosmotic solutions.

The imbalance of Th17/Treg via STAT3 activation modulates cognitive impairment in P. gingivalis LPS-induced periodontitis mice

Periodontitis is one of the most common oral diseases worldwide, and it is associated with various systemic diseases, including cognitive diseases. STAT3 regulates the inflammatory cascade and influences adaptive immunity by modulating Th17/Treg cell differentiation. In this study, we aimed to explore the effect of adaptive immunity inside and outside the brain on the association between periodontitis and cognitive impairment and understand the role of the STAT3 signaling pathway. We established Porphyromonas gingivalis LPS-induced periodontitis mice models by injecting P. gingivalis LPS into the gingival sulcus of mice. Behavioral tests showed that learning and memory abilities were impaired. The flow cytometry data showed an imbalance in the Th17/Treg ratio in the blood and brain samples of the mice. The expression of Th17-related cytokines (IL-1β, IL-17A, IL-21, and IL-22) increased, whereas that of Treg-related cytokines (IL-2 and IL-10) decreased in both the blood and the brain. The level of LPS increased and the STAT3 signaling pathway was activated during this process. These effects were reversed by C188-9, a STAT3 inhibitor. In conclusion, P. gingivalis LPS-induced periodontitis may promote the occurrence and progression of cognitive impairment by modulating the Th17/Treg balance inside and outside the brain. The STAT3 signaling pathway may have immunoregulatory effects on the mouth-to-brain axis.

Modulating neuroinflammation in neurodegeneration-related dementia: can microglial toll-like receptors pull the plug?

Neurodegeneration-associated dementia disorders (NADDs), namely Alzheimer and Parkinson diseases, are developed by a significant portion of the elderly population globally. Extensive research has provided critical insights into the molecular basis of the pathological advancements of these diseases, but an efficient curative therapy seems elusive. A common attribute of NADDs is neuroinflammation due to a chronic inflammatory response within the central nervous system (CNS), which is primarily modulated by microglia. This response within the CNS is positively regulated by cytokines, chemokines, secondary messengers or cyclic nucleotides, and free radicals. Microglia mediated immune activation is regulated by a positive feedback loop in NADDs. The present review focuses on evaluating the crosstalk between inflammatory mediators and microglia, which aggravates both the clinical progression and extent of NADDs by forming a persistent chronic inflammatory milieu within the CNS. We also discuss the role of the human gut microbiota and its effect on NADDs as well as the suitability of targeting toll-like receptors for an immunotherapeutic intervention targeting the deflation of an inflamed milieu within the CNS.

Gut Dysbiosis and Western Diet in the Pathogenesis of Essential Arterial Hypertension: A Narrative Review

Metabolic syndrome is a cluster of the most dangerous cardiovascular (CV) risk factors including visceral obesity, insulin resistance, hyperglycemia, alterations in lipid metabolism and arterial hypertension (AH). In particular, AH plays a key role in the complications associated with metabolic syndrome. High salt intake is a well-known risk factor for AH and CV diseases. Vasoconstriction, impaired vasodilation, extracellular volume expansion, inflammation, and an increased sympathetic nervous system (SNS) activity are the mechanisms involved in the pathogenesis of AH, induced by Western diet. Gut dysbiosis in AH is associated with reduction of short chain fatty acid-producing bacteria: acetate, butyrate and propionate, which activate different pathways, causing vasoconstriction, impaired vasodilation, salt and water retention and a consequent high blood pressure. Moreover, increased trimethylamine N-oxide and lipopolysaccharides trigger chronic inflammation, which contributes to endothelial dysfunction and target organs damage. Additionally, a high salt-intake diet impacts negatively on gut microbiota composition. A bidirectional neuronal pathway determines the "brain-gut" axis, which, in turn, influences blood pressure levels. Then, we discuss the possible adjuvant novel treatments related to gut microbiota modulation for AH control.

The Impact of SARS-CoV-2 Infection on the Development of Neurodegeneration in Multiple Sclerosis

The novel coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global challenge. Currently, there is some information on the consequences of COVID-19 infection in multiple sclerosis (MS) patients, as it is a newly discovered coronavirus, but its far-reaching effects on participation in neurodegenerative diseases seem to be significant. Recent cases reports showed that SARS-CoV-2 may be responsible for initiating the demyelination process in people who previously had no symptoms associated with any nervous system disorders. It is presently known that infection of SARS-CoV-2 evokes cytokine storm syndrome, which may be one of the factors leading to the acute cerebrovascular disease. One of the substantial problems is the coexistence of cerebrovascular disease and MS in an individual's life span. Epidemiological studies showed an enhanced risk of death rate from vascular disabilities in MS patients of approximately 30%. It has been demonstrated that patients with severe SARS-CoV-2 infection usually show increased levels of D-dimer, fibrinogen, C-reactive protein (CRP), and overactivation of blood platelets, which are essential elements of prothrombotic events. In this review, the latest knowledge gathered during an ongoing pandemic of SARS-CoV-2 infection on the neurodegeneration processes in MS is discussed.

Effects of RORγt overexpression on the murine central nervous system

Objective

T helper 17 (Th17) cells are a subset of CD4⁺ T cells that produce interleukin (IL)‐17A. Recent studies showed that an increase in circulating IL‐17A causes cognitive dysfunction, although it is unknown how increased systemic IL‐17A affects brain function. Using transgenic mice overexpressing RORγt, a transcription factor essential for differentiation of Th17 cells (RORγt Tg mice), we examined changes in the brain caused by chronically increased IL‐17A resulting from excessive activation of Th17 cells.

Results

RORγt Tg mice exhibited elevated Rorc and IL‐17A mRNA expression in the colon, as well as a chronic increase in circulating IL‐17A. We found that the immunoreactivity of Iba1 and density of microglia were lower in the dentate gyrus of RORγt Tg mice compared with wild‐type mice. However, GFAP⁺ astrocytes were unchanged in the hippocampi of RORγt Tg mice. Levels of synaptic proteins were not significantly different between RORγt Tg and wild‐type mouse brains. In addition, novel object location test results indicated no difference in preference between these mice.

Conclusion

Our findings indicate that a continuous increase of IL‐17A in response to RORγt overexpression resulted in decreased microglia activity in the dentate gyrus, but had only a subtle effect on murine hippocampal functions.

Using transgenic mice overexpressing RORγt, a transcription factor essential for differentiation of Th17 cells, we examined changes in the brain caused by chronically increased IL‐17A resulting from excessive activation of Th17 cells. RORγt Tg mice exhibited elevated Rorc and IL‐17A mRNA expression in the colon, as well as a chronic increase in circulating IL‐17A. Our findings indicate that a continuous increase of IL‐17A in response to RORγt overexpression resulted in decreased microglia activity in the dentate gyrus but had a subtle effect on murine hippocampal functions.

Gut permeability and cognitive decline: A pilot investigation in the Northern Manhattan Study

Background

Gut microbiota may impact cognitive function and decline, though data are limited. This pilot study examines the associations between gut dysbiosis products, plasma lipopolysaccharide (LPS) and soluble CD14 (sCD14), with cognitive decline and immune molecule activation among 40 participants in the longitudinal population-based Northern Manhattan Study.

Methods

We selected stroke- and dementia-free participants at baseline with high activation levels of core components of the immune signaling pathways underlying microbiota metabolite-cognitive associations (IL-1, IL-17, TNF). Participants were followed with up to three complete neuropsychological assessments, at least 5 years apart.

Results

Elevated sCD14 was associated with high levels of IL-1 pathway activation (p ​< ​0.05), whereas in samples where only those molecules within the IL-17 and TNF pathways were increased, LPS and sCD14 levels were not elevated. LPS was associated with decline in global cognitive performance over 2–3 assessments (adjusted β ​= ​-0.023 per SD per year, 95% CI:-0.036, −0.010). The association between sCD14 and cognitive decline was marginal (adjusted β ​= ​-0.018 per SD per year, 95% CI:-0.040, 0.004).

Conclusions

These preliminary data support the hypothesis that gut dysbiosis leads to systemic and neuro-inflammation, and subsequently cognitive decline. Further large targeted and untargeted gut microbiota-derived metabolomic studies are needed.

Interleukin-17 induced by cumulative mild stress promoted depression-like behaviors in young adult mice

The number of young adult patients with major depression, one of the most common mental disorders, is gradually increasing in modern society. Stressful experiences in early life are considered one of the risk factors for chronic depressive symptoms, along with an abnormal inflammatory response in later life. Although increased inflammatory activity has been identified in patients with depression, the cause of long-lasting depressive states is still unclear. To identify the effects of cumulative mild stress in brain development periods, we generated a young adult depression mouse model exposed to cumulative mild stress (CPMS; cumulative mild prenatal stress, mild maternal separation, and mild social defeat) to mimic early life adversities. CPMS mice exhibited more long-lasting anxiety and depression-like behaviors than groups exposed to single or double combinations of mild stress in young adult age. Using the molecular works, we found that inflammatory cytokines, especially interleukin (IL)-17, upregulated microglial activation in the hippocampus, amygdala, and prefrontal cortex of CPMS mice. In the brains of CPMS mice, we also identified changes in the T helper (Th)-17 cell population as well as differentiation. Finally, anti-IL-17 treatment rescued anxiety and depression-like behavior in CPMS mice. In conclusion, we found that cumulative mild stress promoted long-lasting depressive symptoms in CPMS mice through the upregulation of IL-17. We suggest that the CPMS model may be useful to study young adult depression and expect that IL-17 may be an important therapeutic target for depression in young adults.

Cellular and Molecular Mechanisms of R/S-Roscovitine and CDKs Related Inhibition under Both Focal and Global Cerebral Ischemia: A Focus on Neurovascular Unit and Immune Cells

Ischemic stroke is the second leading cause of death worldwide. Following ischemic stroke, Neurovascular Unit (NVU) inflammation and peripheral leucocytes infiltration are major contributors to the extension of brain lesions. For a long time restricted to neurons, the 10 past years have shown the emergence of an increasing number of studies focusing on the role of Cyclin-Dependent Kinases (CDKs) on the other cells of NVU, as well as on the leucocytes. The most widely used CDKs inhibitor, (R)-roscovitine, and its (S) isomer both decreased brain lesions in models of global and focal cerebral ischemia. We previously showed that (S)-roscovitine acted, at least, by modulating NVU response to ischemia. Interestingly, roscovitine was shown to decrease leucocytes-mediated inflammation in several inflammatory models. Specific inhibition of roscovitine majors target CDK 1, 2, 5, 7, and 9 showed that these CDKs played key roles in inflammatory processes of NVU cells and leucocytes after brain lesions, including ischemic stroke. The data summarized here support the investigation of roscovitine as a potential therapeutic agent for the treatment of ischemic stroke, and provide an overview of CDK 1, 2, 5, 7, and 9 functions in brain cells and leucocytes during cerebral ischemia.

CD8+ T Cell-Mediated Mechanisms Contribute to the Progression of Neurocognitive Impairment in Both Multiple Sclerosis and Alzheimer's Disease?

Neurocognitive impairment (NCI) is one of the most relevant clinical manifestations of multiple sclerosis (MS). The profile of NCI and the structural and functional changes in the brain structures relevant for cognition in MS share some similarities to those in Alzheimer's disease (AD), the most common cause of neurocognitive disorders. Additionally, despite clear etiopathological differences between MS and AD, an accumulation of effector/memory CD8+ T cells and CD8+ tissue-resident memory T (Trm) cells in cognitively relevant brain structures of MS/AD patients, and higher frequency of effector/memory CD8+ T cells re-expressing CD45RA (TEMRA) with high capacity to secrete cytotoxic molecules and proinflammatory cytokines in their blood, were found. Thus, an active pathogenetic role of CD8+ T cells in the progression of MS and AD may be assumed. In this mini-review, findings supporting the putative role of CD8+ T cells in the pathogenesis of MS and AD are displayed, and putative mechanisms underlying their pathogenetic action are discussed. A special effort was made to identify the gaps in the current knowledge about the role of CD8+ T cells in the development of NCI to "catalyze" translational research leading to new feasible therapeutic interventions.

Comparison between cerebrospinal fluid and serum levels of myelin-associated glycoprotein, total antioxidant capacity, and 8-hydroxy-2'-deoxyguanosine in patients with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory disease characterized by demyelinated lesions in the brain, the spinal cord, and the optic nerve. It is one of the most common neurological disorders. In this study, serum and cerebrospinal fluid (CSF) levels of total antioxidant capacity (TAC), myelin-associated glycoprotein (MAG), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were investigated to determine their effects on MS.

MATERIALS AND METHOD

In this study, 25 serum and cerebrospinal samples from MS patients as a case group and 40 serum and CSF samples from healthy participants as a control group were collected and analyzed. Concentrations of TAC, MAG, and 8-OhdG were determined in the samples using a dedicated kit and relayed using the ELISA device.

RESULTS

The mean serum antibody levels of MAG and TAC were higher in the case group than the control group, although the difference in the MAG level was not significant (P > 0.05). However, the mean serum level of -8 OHdG was lower in the case group than the control group. Moreover, the mean levels of the evaluated biomarkers in the CSF samples were higher in the case group than in the control group. Still, the difference was only significant in terms of TAC levels (P < 0.05). Receiver operating characteristics curve analysis showed that the area under the curve was 0.71 and 0.69 for 8-OhdG and TAC serum levels, respectively, and 0.73 for both TAC and CSF levels, which was not significantly different from that in other biomarkers.

CONCLUSION

Elevated TAC levels in serum and CSF samples and 8-OhdG in serum samples may be associated with MS pathogenesis. However, further investigation is needed to consider these cases as a follow-up to the therapeutic goals or treatment process.

Paradoxical Effects of a Cytokine and an Anticonvulsant Strengthen the Epigenetic/Enzymatic Avenue for Autism Research

Maternal exposure to the valproate short-chain fatty acid (SCFA) during pregnancy is known to possibly induce autism spectrum disorders (ASDs) in the offspring. By contrast, case studies have evidenced positive outcomes of this anticonvulsant drug in children with severe autism. Interestingly, the same paradoxical pattern applies to the IL-17a inflammatory cytokine involved in the immune system regulation. Such joint apparent contradictions can be overcome by pointing out that, among their respective signaling pathways, valproate and IL-17a share an enhancement of the “type A monoamine oxidase” (MAOA) enzyme carried by the X chromosome. In the Guided Propagation (GP) model of autism, such enzymatic rise triggers a prenatal epigenetic downregulation, which, without possible X-inactivation, and when coinciding with genetic expression variants of other brain enzymes, results in the delayed onset of autistic symptoms. The underlying imbalance of synaptic monoamines, serotonin in the first place, would reflect a mismatch between the environment to which the brain metabolism was prepared during gestation and the postnatal actual surroundings. Following a prenatal exposure to molecules that significantly elicit the MAOA gene expression, a daily treatment with the same metabolic impact would tend to recreate the fetal environment and contribute to rebalance monoamines, thus allowing proper neural circuits to gradually develop, provided behavioral re-education. Given the multifaceted other players than MAOA that are involved in the regulation of serotonin levels, potential compensatory effects are surveyed, which may underlie the autism heterogeneity. This explanatory framework opens up prospects regarding autism prevention and treatment, strikingly in line with current advances along the gut microbiome–brain axis.

Dysregulated bile acid receptor-mediated signaling and IL-17A induction are implicated in diet-associated hepatic health and cognitive function

BACKGROUND

Chronic consumption of high sugar and high fat diet associated with liver inflammation and cognitive decline. This paper tests a hypothesis that the development and resolution of diet-induced nonalcoholic fatty liver disease (NAFLD) has an impact on neuroplasticity and cognition.

METHODS

C57BL/6 wild-type mice were fed with either a healthy control diet (CD) or a fructose, palmitate, and cholesterol (FPC)-enriched diet since weaning. When mice were 3-months old, FPC diet-fed mice were randomly assigned to receive either FPC-enriched diet with or without 6% inulin supplementation. At 8 months of age, all three groups of mice were euthanized followed by analysis of inflammatory signaling in the liver and brain, gut microbiota, and cecal metabolites.

RESULTS

Our data showed that FPC diet intake induced hepatic steatosis and inflammation in the liver and brain along with elevated RORγ and IL-17A signaling. Accompanied by microglia activation and reduced hippocampal long-term potentiation, FPC diet intake also reduced postsynaptic density-95 and brain derived neurotrophic factor, whereas inulin supplementation prevented diet-reduced neuroplasticity and the development of NAFLD. In the gut, FPC diet increased Coriobacteriaceae and Erysipelotrichaceae, which are implicated in cholesterol metabolism, and the genus Allobaculum, and inulin supplementation reduced them. Furthermore, FPC diet reduced FXR and TGR5 signaling, and inulin supplementation reversed these changes. Untargeted cecal metabolomics profiling uncovered 273 metabolites, and 104 had significant changes due to FPC diet intake or inulin supplementation. Among the top 10 most affected metabolites, FPC-fed mice had marked increase of zymosterol, a cholesterol biosynthesis metabolite, and reduced 2,8-dihydroxyquinoline, which has known benefits in reducing glucose intolerance; these changes were reversible by inulin supplementation. Additionally, the abundance of Barnesiella, Coprobacter, Clostridium XIVa, and Butyrivibrio were negatively correlated with FPC diet intake and the concentration of cecal zymosterol but positively associated with inulin supplementation, suggesting their benefits.

CONCLUSION

Taken together, the presented data suggest that diet alters the gut microbiota and their metabolites, including bile acids. This will subsequently affect IL-17A signaling, resulting in systemic impacts on both hepatic metabolism and cognitive function.

Immune activity at birth and later psychopathology in childhood

Disruption of neurodevelopmental trajectories can alter brain circuitry and increase the risk of psychopathology later in life. While preclinical studies have demonstrated that the immune system and cytokines influence neurodevelopment, whether immune activity and in particular which cytokines at birth are associated with psychopathology remains poorly explored in children. We used data and biological samples from 869 mother-child pairs participating in the French mother-child cohort EDEN. As proxies for immune activity at birth, we measured the levels of 27 cytokines in umbilical cord blood sera (CBS). We then explored the association between CBS cytokine levels and five psychopathological dimensions assessed in 5-year-old children using the Strengths and Difficulties Questionnaire (SDQ). Five cytokines were positively associated with psychopathology: C-X-C motif chemokine Ligand (CXCL)10, interleukin (IL)-10 and IL-12p40 with emotional symptoms, C–C motif chemokine Ligand (CCL)11 with conduct problems, and CCL11, and IL-17A with peer relationships problems. In contrast, seven cytokines were negatively associated with psychopathology: IL-7, IL-15 and Tumor Necrosis Factor (TNF)-β with emotional symptoms, CCL4 and IL-6 with conduct problems, CCL26 and IL-15 with peer relationships problems, and CCL26, IL-7, IL-15, and TNF-α with abnormal prosocial behavior. Without implying causation, these associations support the notion that cytokines influence neurodevelopment in humans and the risk of psychopathology later in life.

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Twelve cytokines at birth are associated with psychopathology in 5-year-old children.

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IL-7, IL-10, IL-12p40, IL-15, TNF-β and CXCL10 are associated with emotional symptoms.

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IL-6, CCL4 and CCL11 are associated with conduct problems.

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IL-15, IL-17A, CCL11 and CCL26 are associated with peer relationship problems.

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IL-7, IL-15, TNF-α and CCL26 are associated with prosocial behavior.

The Inflamed Brain in Schizophrenia: The Convergence of Genetic and Environmental Risk Factors That Lead to Uncontrolled Neuroinflammation

Schizophrenia is a disorder with a heterogeneous etiology involving complex interplay between genetic and environmental risk factors. The immune system is now known to play vital roles in nervous system function and pathology through regulating neuronal and glial development, synaptic plasticity, and behavior. In this regard, the immune system is positioned as a common link between the seemingly diverse genetic and environmental risk factors for schizophrenia. Synthesizing information about how the immune-brain axis is affected by multiple factors and how these factors might interact in schizophrenia is necessary to better understand the pathogenesis of this disease. Such knowledge will aid in the development of more translatable animal models that may lead to effective therapeutic interventions. Here, we provide an overview of the genetic risk factors for schizophrenia that modulate immune function. We also explore environmental factors for schizophrenia including exposure to pollution, gut dysbiosis, maternal immune activation and early-life stress, and how the consequences of these risk factors are linked to microglial function and dysfunction. We also propose that morphological and signaling deficits of the blood-brain barrier, as observed in some individuals with schizophrenia, can act as a gateway between peripheral and central nervous system inflammation, thus affecting microglia in their essential functions. Finally, we describe the diverse roles that microglia play in response to neuroinflammation and their impact on brain development and homeostasis, as well as schizophrenia pathophysiology.

The role of TH17 cells in multiple sclerosis: Therapeutic implications

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) where immunopathology is thought to be mediated by myelin-reactive CD4⁺ T helper (TH) cells. The TH cells most commonly implicated in the pathogenesis of the disease are of TH1 and TH17 lineage, which are defined by the production of interferon-γ and interleukin-17, respectively. Moreover, there is emerging evidence for the involvement of TH17.1 cells, which share the hallmarks of TH1 and TH17 subsets. In this review, we summarise current knowledge about the potential role of TH17 subsets in the initiation and progression of the disease and put a focus on their response to approved immunomodulatory MS drugs. In this regard, TH17 cells are abundant in peripheral blood, cerebrospinal fluid and brain lesions of MS patients, and their counts and inflammatory mediators are further increased during relapses. Fingolimod and alemtuzumab induce a paramount decrease in central memory T cells, which harbour the majority of peripheral TH17 cells, while the efficacy of natalizumab, dimethyl fumarate and importantly hematopoietic stem cell therapy correlates with TH17.1 cell inhibition. Interestingly, also CD20 antibodies target highly inflammatory TH cells and hamper TH17 differentiation by IL-6 reductions. Moreover, recovery rates of TH cells best correlate with long-term efficacy after therapeutical immunodepletion. We conclude that central memory TH17.1 cells play a pivotal role in MS pathogenesis and they represent a major target of MS therapeutics.

Antagonistic effects of IL-17 and Astragaloside IV on cortical neurogenesis and cognitive behavior after stroke in adult mice through Akt/GSK-3β pathway

We aimed to investigate the exact effect of IL-17 on regulating neural stem cells (NSCs) stemness and adult neurogenesis in ischemic cortex after stroke, how Astragaloside IV(As-IV) regulated IL-17 expression and the underlying mechanism. Photochemical brain ischemia model was established and IL-17 protein expression was observed at different time after stroke in WT mice. At 3 days after stroke, when IL-17 expression peaked, IL-17 knock out (KO) mice were used to observe cell proliferation and neurogenesis in ischemic cortex. Then, As-IV was administered intravenously to assess cell apoptosis, proliferation, neurogenesis, and cognitive deficits by immunochemistry staining, western blots, and animal behavior tests in WT mice. Furthermore, IL-17 KO mice and As-IV were used simultaneously to evaluate the mechanism of cell apoptosis and proliferation after stroke in vivo. Besides, in vitro, As-IV and recombinant mouse IL-17A was administered, respectively, into NSCs culture, and then their diameters, viable cell proliferation and pathway relevant protein was assessed. The results showed knocking out IL-17 contributed to regulating PI3K/Akt pathway, promoting NSCs proliferation, and neurogenesis after ischemic stroke. Moreover, As-IV treatment helped inhibit neural apoptosis, promote the neurogenesis and eventually relieve mice anxiety after stroke. Unsurprisingly, IL-17 protein expression could be downregulated by As-IV in vivo and in vitro and they exerted antagonistic effect on neurogenesis by regulating Akt/GSK-3β pathway, with significant regulation for apoptosis. In conclusion, IL-17 exerts negative effect on promoting NSCs proliferation, neurogenesis and cognitive deficits after ischemic stroke, which could be reversed by As-IV.

Average daily gain divergence in beef steers is associated with altered plasma metabolome and whole blood immune-related gene expression

We evaluated the plasma amine/phenol- and carbonyl-metabolome and whole-blood immune gene expression profiles in beef steers with divergent average daily gain (ADG). Forty-eight Angus crossbred beef steers (21 days postweaning; 210 ± 8.5 kg of body weight) were fed the same total mixed ration ad libitum for 42 days with free access to water. After 42 days of feeding, the steers were divided into two groups of lowest (LF: n = 8) and highest ADG (HF: n = 8). Blood samples were taken from all steers. The blood samples from LF and HF steers were used for further analysis. A subsample of the whole blood was immediately transferred into RNA-protect tubes for RNA extraction and messenger RNA expressions of 84 genes involved in innate and adaptive immune responses. Another subsample of the whole blood was immediately centrifuged to harvest the plasma for subsequent metabolome analysis. The average daily dry matter intake of the steers in LF and HF was 6.08 kg ± 0.57 and 6.04 kg ± 0.42, respectively, and was similar between the two groups (P = 0.72). The ADG (1.09 kg ± 0.13) of LF was lower (P = 0.01) than that of HF (1.63 kg ± 0.20). The expressions of 10 immune-related genes were upregulated (FC ≥ 1.2; P ≤ 0.05) in HF steers; these genes were involved in viral pathogen recognition and eradication, defense against intracellular and extracellular pathogens and parasites, and immune response homeostasis. A total number of 42 carbonyl-containing metabolites and 229 amine/phenol-containing metabolites were identified in the plasma samples of both groups. No alteration in carbonyl-metabolome was detected. Ten metabolites with immunomodulatory, anti-inflammatory, and reactive oxygen-scavenging properties were greater (FDR ≤ 0.05) in HF steers, whereas eight metabolites including arginine, phenylalanine, guanidoacetic acid, and aspartyl-threonine were greater in LF steers. This study demonstrated that beef steers with divergent ADG had altered plasma amine/phenol metabolome and immune-related gene expressions in the blood. Notably, plasma metabolites and immune-related genes of great health benefits were greater in steers with high ADG.