Intermittent Fasting Alleviates the Increase of Lipoprotein Lipase Expression in Brain of a Mouse Model of Alzheimer's Disease: Possibly Mediated by β-hydroxybutyrate

β-Hydroxybutyrate as an epigenetic modifier: Underlying mechanisms and implications

Previous studies have found that β-Hydroxybutyrate (BHB), the main component of ketone bodies, is of physiological importance as a backup energy source during starvation or induces diabetic ketoacidosis when insulin deficiency occurs. Ketogenic diets (KD) have been used as metabolic therapy for over a hundred years, it is well known that ketone bodies and BHB not only serve as ancillary fuel substituting for glucose but also induce anti-oxidative, anti-inflammatory, and cardioprotective features via binding to several target proteins, including histone deacetylase (HDAC), or G protein-coupled receptors (GPCRs). Recent advances in epigenetics, especially novel histone post-translational modifications (HPTMs), have continuously updated our understanding of BHB, which also acts as a signal transduction molecule and modification substrate to regulate a series of epigenetic phenomena, such as histone acetylation, histone β-hydroxybutyrylation, histone methylation, DNA methylation, and microRNAs. These epigenetic events alter the activity of genes without changing the DNA structure and further participate in the pathogenesis of related diseases. This review focuses on the metabolic process of BHB and BHB-mediated epigenetics in cardiovascular diseases, diabetes and complications of diabetes, neuropsychiatric diseases, cancers, osteoporosis, liver and kidney injury, embryonic and fetal development, and intestinal homeostasis, and discusses potential molecular mechanisms, drug targets, and application prospects.

Single-nucleus RNA-sequencing of autosomal dominant Alzheimer disease and risk variant carriers

Genetic studies of Alzheimer disease (AD) have prioritized variants in genes related to the amyloid cascade, lipid metabolism, and neuroimmune modulation. However, the cell-specific effect of variants in these genes is not fully understood. Here, we perform single-nucleus RNA-sequencing (snRNA-seq) on nearly 300,000 nuclei from the parietal cortex of AD autosomal dominant (APP and PSEN1) and risk-modifying variant (APOE, TREM2 and MS4A) carriers. Within individual cell types, we capture genes commonly dysregulated across variant groups. However, specific transcriptional states are more prevalent within variant carriers. TREM2 oligodendrocytes show a dysregulated autophagy-lysosomal pathway, MS4A microglia have dysregulated complement cascade genes, and APOEε4 inhibitory neurons display signs of ferroptosis. All cell types have enriched states in autosomal dominant carriers. We leverage differential expression and single-nucleus ATAC-seq to map GWAS signals to effector cell types including the NCK2 signal to neurons in addition to the initially proposed microglia. Overall, our results provide insights into the transcriptional diversity resulting from AD genetic architecture and cellular heterogeneity. The data can be explored on the online browser ( http://web.hararilab.org/SNARE/ ).

In situ silver nanoparticle development for molecular-specific biological imaging via highly accessible microscopies

In biological studies and diagnoses, brightfield (BF), fluorescence, and electron microscopy (EM) are used to image biomolecules inside cells. When compared, their relative advantages and disadvantages are obvious. BF microscopy is the most accessible of the three, but its resolution is limited to a few microns. EM provides a nanoscale resolution, but sample preparation is time-consuming. In this study, we present a new imaging technique, which we termed decoration microscopy (DecoM), and quantitative investigations to address the aforementioned issues in EM and BF microscopy. For molecular-specific EM imaging, DecoM labels proteins inside cells using antibodies bearing 1.4 nm gold nanoparticles (AuNPs) and grows silver layers on the AuNPs' surfaces. The cells are then dried without buffer exchange and imaged using scanning electron microscopy (SEM). Structures labeled with silver-grown AuNPs are clearly visible on SEM, even they are covered with lipid membranes. Using stochastic optical reconstruction microscopy, we show that the drying process causes negligible distortion of structures and that less structural deformation could be achieved through simple buffer exchange to hexamethyldisilazane. Using DecoM, we visualize the nanoscale alterations in microtubules by microtubule-severing proteins that cannot be observed with diffraction-limited fluorescence microscopy. We then combine DecoM with expansion microscopy to enable sub-micron resolution BF microscopy imaging. We first show that silver-grown AuNPs strongly absorb white light, and the structures labeled with them are clearly visible on BF microscopy. We then show that the application of AuNPs and silver development must follow expansion to visualize the labeled proteins clearly with sub-micron resolution.

Fasting: From Physiology to Pathology

Overnutrition is a risk factor for various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. Therefore, targeting overnutrition represents a simple but attractive strategy for the treatment of these increasing public health threats. Fasting as a dietary intervention for combating overnutrition has been extensively studied. Fasting has been practiced for millennia, but only recently have its roles in the molecular clock, gut microbiome, and tissue homeostasis and function emerged. Fasting can slow aging in most species and protect against various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. These centuried and unfading adventures and explorations suggest that fasting has the potential to delay aging and help prevent and treat diseases while minimizing side effects caused by chronic dietary interventions. In this review, recent animal and human studies concerning the role and underlying mechanism of fasting in physiology and pathology are summarized, the therapeutic potential of fasting is highlighted, and the combination of pharmacological intervention and fasting is discussed as a new treatment regimen for human diseases.

The molecular mechanism of γ-aminobutyric acid against AD: the role of CEBPα/circAPLP2/miR-671-5p in regulating CNTN1/2 expression

The expression levels of the synaptic-related proteins contactin 1/2 (CNTN1/2) are down-regulated in the brain of Alzheimer's disease (AD), but the mechanism has not been clarified. γ-Aminobutyric acid (GABA) is considered a biologically active ingredient in food. Our previous research revealed that GABA can regulate CEBPα expression in Aβ-treated U251 cells. However, it is uncertain whether GABA can antagonize the pathogenesis of AD. Whether GABA can inhibit the reduction in CNTN1/2 expression by regulating CEBPα/circAPLP2/miR-671-5p in the AD brain remains unclear yet. Here, we demonstrate that GABA could attenuate the deposition of Aβ in the brain and ameliorate cognitive impairments in AD model mice. The expressions of CEBPα, circAPLP2, and CNTN1/2 were decreased and that of miR-671-5p was increased in AD model mouse brains and Aβ-induced SH-SY5Y cells. These alterations were partly reversed by GABA. The CNTN1/2 expression was down-regulated and up-regulated in SH-SY5Y cells treated with miR-671-5p mimics and miR-671-5p inhibitors, respectively. The results from the luciferase reporter assay revealed that miR-671-5p could bind to the 3'-untranslated region of circAPLP2. The silencing of circAPLP2 with the siRNA duplex caused an up-regulation of miR-671-5p and a down-regulation of CNTN1/2 in SH-SY5Y cells. The silencing of CEBPα with the siRNA duplex caused a down-regulation of circAPLP2 or CNTN1/2 and an up-regulation of miR-671-5p. In conclusion, GABA may decrease the deposition of Aβ in the brain, inhibit the down-regulation of CNTN1/2 expression, and ameliorate the cognitive deficits of AD model mice. The CEBPα/circAPLP2/miR-671-5p pathway plays a role in regulating CNTN1/2 expression by GABA in AD.

Complementary and Alternative Medicine Approaches in Alzheimer Disease and Other Neurocognitive Disorders

As our population ages, there is interest in delaying or intervening in cognitive decline. While newer agents are under development, agents in mainstream use do not impact the course of diseases that cause cognitive decline. This increases interest in alternative strategies. Even as we welcome possible new disease-modifying agents, they are likely to remain costly. Herein, we review the evidence behind other complementary and alternative strategies for cognitive enhancement and prevention of cognitive decline.

Heat shock protein amplification improves cerebellar myelination in the Npc1nih mouse model

BACKGROUND

Niemann-Pick disease type C (NPC) is a rare prematurely fatal lysosomal lipid storage disease with limited therapeutic options. The prominent neuropathological hallmarks include hypomyelination and cerebellar atrophy. We previously demonstrated the efficacy of recombinant human heat shock protein 70 (rhHSP70) in preclinical models of the disease. It reduced glycosphingolipid levels in the central nervous system (CNS), improving cerebellar myelination and improved behavioural phenotypes in Npc1^nih (Npc1^-/-) mice. Furthermore, treatment with arimoclomol, a well-characterised HSP amplifier, attenuated lysosomal storage in NPC patient fibroblasts and improved neurological symptoms in Npc1^-/- mice. Taken together, these findings prompted the investigation of the effects of HSP amplification on CNS myelination.

METHODS

We administered bimoclomol daily or rhHSP70 6 times per week to Npc1^-/- (BALB/cNctr-Npc1^m1N/J, also named Npc1^nih) mice by intraperitoneal injection from P7 through P34 to investigate the impact on CNS myelination. The Src-kinase inhibitor saracatinib was administered with/without bimoclomol twice daily to explore the contribution of Fyn kinase to bimoclomol's effects.

FINDINGS

Treatment with either bimoclomol or rhHSP70 improved myelination and increased the numbers of mature oligodendrocytes (OLs) as well as the ratio of active-to-inactive forms of phosphorylated Fyn kinase in the cerebellum of Npc1^-/- mice. Additionally, treatment with bimoclomol preserved cerebellar weight, an effect that was abrogated when co-administered with saracatinib, an inhibitor of Fyn kinase. Bimoclomol-treated mice also exhibited increased numbers of immature OLs within the cortex.

INTERPRETATION

These data increase our understanding of the mechanisms by which HSP70 regulates myelination and provide further support for the clinical development of HSP-amplifying therapies in the treatment of NPC.

FUNDING

Funding for this study was provided by Orphazyme A/S (Copenhagen, Denmark) and a Pathfinder Award from The Wellcome Trust.

Amyloid beta and its naturally occurring N-terminal variants are potent activators of human and mouse formyl peptide receptor 1

Formyl peptide receptors (FPRs) may contribute to inflammation in Alzheimer's disease through interactions with neuropathological Amyloid beta (Aβ) peptides. Previous studies reported activation of FPR2 by Aβ_1-42, but further investigation of other FPRs and Aβ variants is needed. This study provides a comprehensive overview of the interactions of mouse and human FPRs with different physiologically relevant Aβ-peptides using transiently transfected cells in combination with calcium imaging. We observed that, in addition to hFPR2, all other hFPRs also responded to Aβ_1-42, Aβ_1-40, and the naturally occurring variants Aβ_11-40 and Aβ_17-40. Notably, Aβ_11-40 and Aβ_17-40 are very potent activators of mouse and human FPR1, acting at nanomolar concentrations. Buffer composition and aggregation state are extremely crucial factors that critically affect the interaction of Aβ with different FPR subtypes. To investigate the physiological relevance of these findings, we examined the effects of Aβ_11-40 and Aβ_17-40 on the human glial cell line U87. Both peptides induced a strong calcium flux at concentrations that are very similar to those obtained in experiments for hFPR1 in HEK cells. Further immunocytochemistry, qPCR, and pharmacological experiments verified that these responses were primarily mediated through hFPR1. Chemotaxis experiments revealed that Aβ_11-40 but not Aβ_17-40 evoked cell migration, which argues for a functional selectivity of different Aβ peptides. Together, these findings provide the first evidence that not only hFPR2 but also hFPR1 and hFPR3 may contribute to neuroinflammation in Alzheimer's disease through an interaction with different Aβ variants.

Association between vascular endothelial growth factor-mediated blood-brain barrier dysfunction and stress-induced depression

Several lines of evidence suggest that stress induces the neurovascular dysfunction associated with increased blood-brain barrier (BBB) permeability, which could be an important pathology linking stress and psychiatric disorders, including major depressive disorder (MDD). However, the detailed mechanism resulting in BBB dysfunction associated in the pathophysiology of MDD still remains unclear. Herein, we demonstrate the role of vascular endothelial growth factor (VEGF), a key mediator of vascular angiogenesis and BBB permeability, in stress-induced BBB dysfunction and depressive-like behavior development. We implemented an animal model of depression, chronic restraint stress (RS) in BALB/c mice, and found that the BBB permeability was significantly increased in chronically stressed mice. Immunohistochemical and electron microscopic observations revealed that increased BBB permeability was associated with both paracellular and transcellular barrier alterations in the brain endothelial cells. Pharmacological inhibition of VEGF receptor 2 (VEGFR2) using a specific monoclonal antibody (DC101) prevented chronic RS-induced BBB permeability and anhedonic behavior. Considered together, these results indicate that VEGF/VEGFR2 plays a crucial role in the pathogenesis of depression by increasing the BBB permeability, and suggest that VEGFR2 inhibition could be a potential therapeutic strategy for the MDD subtype associated with BBB dysfunction.

Opioid receptor activation suppresses the neuroinflammatory response by promoting microglial M2 polarization

Activation of microglia is considered the most important component of neuroinflammation. Microglia can adopt a pro-inflammatory (M1) or anti-inflammatory (M2) phenotype. Opioid receptors (ORs) have been shown to control neurotransmission of various peptidergic neurons, but their potential role in regulating microglial function is largely unknown. Here, we aimed to investigate the effect of the OR agonists DAMGO, DADLE and U-50488 on the polarization of C8-B4 microglial cells. We observed that opioids suppressed lipopolysaccharide (LPS)-triggered M1 polarization and promoted M2 polarization. This was reflected in lower phagocytic activity, lower production of NO, lower expression of TNF-α, IL-1β, IL-6, IL-86 and IL-12 beta p40 together with higher migration rate, and increased expression of IL-4, IL-10, arginase 1 and CD 206 in microglia, compared to cells affected by LPS. We demonstrated that the effect of opioids on microglial polarization is mediated by the TREM2/NF-κB signaling pathway. These results provide new insights into the anti-inflammatory and neuroprotective effects of opioids and highlight their potential in combating neurodegenerative diseases.

Comparing emotional working memory in adolescents and young adults with and without depressive symptoms: developmental and psychopathological differences

Depressive symptoms are associated with working memory impairments. Yet, comparative studies examining working memory across the developmental spectrum in depressed and non depressed cohorts are lacking. This study examined emotional working memory in 74 adolescents (mean age = 14; 21 with depressive symptoms) and 92 adults (mean age = 22; 36 with depressive symptoms). Participants completed two versions of an emotional face n-back task, and either paid attention to the valence of the emotion or the gender. Both tasks were completed at low load (0-back) and high load (2-back). In the high load condition, healthy adolescents showed a bias towards positive faces, both speeding up reaction times (RTs) when emotion was task relevant but slowing RTs when they were task irrelevant. This interaction was neither significant in adolescents with depressive symptoms nor in young adults. Depressive symptoms did not influence RTs in low load. The results indicate that adolescents with depressive symptoms might lack the bias towards positive affective material at high load WM task present in healthy adolescents.

A closer look at sex pheromone autodetection in the Oriental fruit moth

Female moths emit sex pheromone to attracts males, and although they are not attracted to their own sex pheromone, they appear to detect it as it affects their behavior. In order to elucidate the mechanism of pheromone “autodetection” we compared responses of olfactory receptor neurons (ORNs) of male and female Grapholita molesta, a species with reported pheromone autodetection. Two concentrations of the major (Z8-12:Ac) and minor (E8-12:Ac) sex pheromone components, a plant-volatile blend containing methyl salicylate, terpinyl acetate and (E)-β-farnesene, and the male-produced hair-pencil (i.e., courtship) pheromone (ethyl trans-cinnamate) were tested in 45 male and 305 female ORNs. Hierarchical cluster analysis showed radically different peripheral olfactory systems between sexes that could be linked to their specific roles. In males 63% of the ORNs were tuned specifically to the major or minor female sex pheromone components, and 4% to the plant volatile blend, while the remaining 33% showed unspecific responses to the stimulus panel. In females 3% of the ORNs were specifically tuned to the male hair-pencil pheromone, 6% to the plant volatile blend, 91% were unspecific, and no ORN was tuned their own sex pheromone components. The lack of sex pheromone-specific ORNs in females suggests that they are not able to discriminate pheromone blends, and thus pheromone autodetection is unlikely in this species. We discuss our results in the context of the methodological limitations inherent to odor stimulation studies.

Indoor green wall affects health-associated commensal skin microbiota and enhances immune regulation: a randomized trial among urban office workers

Urbanization reduces microbiological abundance and diversity, which has been associated with immune mediated diseases. Urban greening may be used as a prophylactic method to restore microbiological diversity in cities and among urbanites. This study evaluated the impact of air-circulating green walls on bacterial abundance and diversity on human skin, and on immune responses determined by blood cytokine measurements. Human subjects working in offices in two Finnish cities (Lahti and Tampere) participated in a two-week intervention, where green walls were installed in the rooms of the experimental group. Control group worked without green walls. Skin and blood samples were collected before (Day0), during (Day14) and two weeks after (Day28) the intervention. The relative abundance of genus Lactobacillus and the Shannon diversity of phylum Proteobacteria and class Gammaproteobacteria increased in the experimental group. Proteobacterial diversity was connected to the lower proinflammatory cytokine IL-17A level among participants in Lahti. In addition, the change in TGF-β1 levels was opposite between the experimental and control group. As skin Lactobacillus and the diversity of Proteobacteria and Gammaproteobacteria are considered advantageous for skin health, air-circulating green walls may induce beneficial changes in a human microbiome. The immunomodulatory potential of air-circulating green walls deserves further research attention.

The neuroprotective effects of intermittent fasting on brain aging and neurodegenerative diseases via regulating mitochondrial function

Intermittent fasting (IF) has been studied for its effects on lifespan and the prevention or delay of age-related diseases upon the regulation of metabolic pathways. Mitochondria participate in key metabolic pathways and play important roles in maintaining intracellular signaling networks that modulate various cellular functions. Mitochondrial dysfunction has been described as an early feature of brain aging and neurodegeneration. Although IF has been shown to prevent brain aging and neurodegeneration, the mechanism is still unclear. This review focuses on the mechanisms by which IF improves mitochondrial function, which plays a central role in brain aging and neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. The cellular and molecular mechanisms of IF in brain aging and neurodegeneration involve activation of adaptive cellular stress responses and signaling- and transcriptional pathways, thereby enhancing mitochondrial function, by promoting energy metabolism and reducing oxidant production.

Can dietary patterns prevent cognitive impairment and reduce Alzheimer's disease risk: exploring the underlying mechanisms of effects

Alzheimer's disease (AD) is one of the fastest growing cognitive decline-related neurological diseases. To date, effective curative strategies have remained elusive. A growing body of evidence indicates that dietary patterns have significant effects on cognitive function and the risk of developing AD. Previous studies on the association between diet and AD risk have mainly focused on individual food components and specific nutrients, and the mechanisms responsible for the beneficial effects of dietary patterns on AD are not well understood. This article provides a comprehensive overview of the effects of dietary patterns, including the Mediterranean diet (MedDiet), dietary approaches to stop hypertension (DASH) diet, Mediterranean-DASH diet intervention for neurological delay (MIND), ketogenic diet, caloric restriction, intermittent fasting, methionine restriction, and low-protein and high-carbohydrate diet, on cognitive impairment and summarizes the underlying mechanisms by which dietary patterns attenuate cognitive impairment, especially highlighting the modulation of dietary patterns on cognitive impairment through gut microbiota. Furthermore, considering the variability in individual metabolic responses to dietary intake, we put forward a framework to develop personalized dietary patterns for people with cognitive disorders or AD based on individual gut microbiome compositions.

Effect of multi-epitope derived from HIV-1 on REM sleep deprivation-induced spatial memory impairment with respect to the level of immune factors in mice

Objectives

Sleep deprivation (SD) has a negative impact on cognitive functions including learning and memory. Many studies have shown that rapid-eye-movement (REM) SD also disrupts memory performance. In this study, we aimed to investigate the effect of multi-epitope Gag-Pol-Env-Tat derived from Human immunodeficiency virus 1 (HIV-1) on REM SD-induced spatial memory impairment with respect to the levels of interleukin-4 (IL-4), interleukin-17 (IL-17), interferon-gamma (IFN-γ), immunoglobulin G1 (IgG1), immunoglobulin G2a (IgG2a), and lymphocyte proliferation in NMRI mice. We used multi-epitope Gag-Pol-Env-Tat derived from HIV-1 because Gag-Pol-Env-Tat immunogen sequence is one of the most sensitive immunogen sequences of HIV-1 that can significantly augment cellular and humoral immune systems, leading to the improvement of cognitive functions.

Materials and Methods

Morris water maze apparatus was used to assess spatial memory, and multi-platform apparatus was used to induce RSD for 24 hr. Multi-epitope derived from HIV-1 was subcutaneously injected at the dose of 20 µgr/ml, once and fourteen days before RSD.

Results

RSD impaired spatial memory and injection of multi-epitope derived from HIV-1 reversed this effect. RSD decreased IL-4, IgG1, and IgG2a levels, while multi-epitope derived from HIV-1 reversed these effects. Multi-epitope derived from HIV-1 also increased lymphocyte proliferation and decreased IL-17 levels in both control and RSD mice.

Conclusion

Multi-epitope derived from HIV-1 may improve memory performance via induction of anti-inflammatory immune response.

The druggability of bitter taste receptors for the treatment of neurodegenerative disorders

The delivery of therapeutic drugs to the brain remains a major pharmacology challenge. A complex system of chemical surveillance to protect the brain from endogenous and exogenous toxicants at brain barriers hinders the uptake of many compounds with significant in vitro and ex vivo therapeutic properties. Despite the advances in the field in recent years, the components of this system are not completely understood. Recently, a large group of chemo-sensing receptors, have been identified in the blood-cerebrospinal fluid barrier. Among these chemo-sensing receptors, bitter taste receptors (TAS2R) hold promise as potential drug targets, as many TAS2R bind compounds with recognized neuroprotective activity (quercetin, resveratrol, among others). Whether activation of TAS2R by their ligands contributes to their diverse biological actions described in other cells and tissues is still debatable. In this review, we discuss the potential role of TAS2R gene family as the mediators of the biological activity of their ligands for the treatment of central nervous system disorders and discuss their potential to counteract drug resistance by improving drug delivery to the brain.

Response of Astrocytes to Blood Exposure due to Shunt Insertion in vitro

The breakdown of the ventricular zone (VZ) with the presence of blood in cerebrospinal fluid (CSF) has been shown to increase shunt catheter obstruction in the treatment of hydrocephalus, but the mechanisms by which this occurs are generally unknown. Using a custom-built incubation chamber, we immunofluorescently assayed cell attachment and morphology on shunt catheters with and without blood after 14 days. Samples exposed to blood showed significantly increased cell attachment (average total cell count 392.0±317.1 versus control of 94.7±44.5, P<0.0001). Analysis of the glial fibrillary acidic protein (GFAP) expression showed similar trends (854.4±450.7 versus control of 174.3±116.5, P<0.0001). An in vitro model was developed to represent the exposure of astrocytes to blood following an increase in BBB permeability. Exposure of astrocytes to blood increases the number of cells and their spread on the shunt.

Gut microbiota-a positive contributor in the process of intermittent fasting-mediated obesity control

Historically, intermittent fasting (IF) has been considered as an effective strategy for controlling the weight of athletes before competition. Along with excellent insight into its application in various spaces by numerous studies, increasing IF-mediated positive effects have been reported, including anti-aging, neuroprotection, especially obesity control. Recently, the gut microbiota has been considered as an essential manipulator for host energy metabolism and its structure has been reported to be sensitive to dietary structure and habits, indicating that there is a potential and strong association between IF and gut microbiota. In this paper, we focus on the crosstalk between these symbionts and energy metabolism during IF which hold the promise to optimize host energy metabolism at various physical positions, including adipose tissue, liver and intestines, and further improve milieu internal homeostasis. Moreover, this paper also discusses the positive function of a potential recommendatory strain (Akkermansia muciniphila) based on the observational data for IF-mediated alternated pattern of gut microbiota and a hopefully regulatory pathway (circadian rhythm) for gut microbiota in IF-involved improvement on host energy metabolism. Finally, this review addresses the limitation and perspective originating from these studies, such as the association with tissue-specific bio-clock and single strain research, which may continuously reveal novel viewpoints and mechanisms to understand the energy metabolism and develop new strategies for treating obesity, diabetes, and metabolic disorders.

A hyperacute immune map of ischaemic stroke patients reveals alterations to circulating innate and adaptive cells

Systemic immune changes following ischaemic stroke are associated with increased susceptibility to infection and poor patient outcome due to their role in exacerbating the ischaemic injury and long-term disability. Alterations to the abundance or function of almost all components of the immune system post-stroke have been identified, including lymphocytes, monocytes and granulocytes. However, subsequent infections have often confounded the identification of stroke-specific effects. Global understanding of very early changes to systemic immunity is critical to identify immune targets to improve clinical outcome. To this end, we performed a small, prospective, observational study in stroke patients with immunophenotyping at a hyperacute time point (< 3 h) to explore early changes to circulating immune cells. We report, for the first time, decreased frequencies of type 1 conventional dendritic cells (cDC1), haematopoietic stem and progenitor cells (HSPCs), unswitched memory B cells and terminally differentiated effector memory T cells re-expressing CD45RA (TEMRA). We also observed concomitant alterations to human leucocyte antigen D-related (HLA-DR), CD64 and CD14 expression in distinct myeloid subsets and a rapid activation of CD4+ T cells based on CD69 expression. The CD69+ CD4+ T cell phenotype inversely correlated with stroke severity and was associated with naive and central memory T (TCM) cells. Our findings highlight early changes in both the innate and adaptive immune compartments for further investigation as they could have implications the development of post-stroke infection and poorer patient outcomes.

Up-regulation of MMP-2 by histone H3K9 β-hydroxybutyrylation to antagonize glomerulosclerosis in diabetic rat

AIMS

Besides energy supply, β-hydroxybutyrate (BHB) acts as a bioactive molecule to play multiple protective roles, even in diabetes and its complications. The aim of this study was to investigate the antagonizing effects of BHB against diabetic glomerulosclerosis and the underlying mechanism.

METHODS

Male Sprague-Dawley rats were intraperitoneally injected with streptozotocin to induce diabetes and then treated with different concentrations of β-hydroxybutyrate. After 10 weeks, body weight, blood glucose, serum creatinine and 24-h urine protein were examined. Glomerular morphological changes and the contents of collagen type IV (COL IV) were evaluated. Then, transforming growth factor (TGF)-β/Smad3 contents and matrix metalloproteinase-2 (MMP-2) generation were detected. Moreover, the total contents of trans-activating histone H3K9 β-hydroxybutyrylation (H3K9bhb) and the contents of H3K9bhb in the Mmp-2 promoter were measured.

RESULTS

It was firstly confirmed that BHB treatments reduced renal biochemical indicators and attenuated glomerular morphological changes of the diabetic rats, with COL IV content decreased in a concentration-dependent manner. Then, BHB treatments were found to up-regulate renal MMP-2 generation of the diabetic rats significantly, while not affecting the increased TGF-β/Smad3 contents. Furthermore, the contents of H3K9bhb in the Mmp-2 promoter were elevated significantly for the middle and high concentrations of BHB treatments, up-regulating MMP-2 generation.

CONCLUSION

BHB treatments could up-regulate MMP-2 generation via causing elevated H3K9bhb in its promoter to antagonize glomerulosclerosis in the diabetic rats.

Vitamin D Deficiency in Autism Spectrum Disorder: A Cross-Sectional Study

Vitamin D plays a role in central nervous system (CNS) development. Recent literature focused on vitamin D status in children and adolescents with autism spectrum disorder (ASD), but with inconsistent results. Our case-control study is aimed at evaluating serum 25-hydroxyl-vitamin D (25(OH)D) concentration in children with ASD (ASD group, n = 54) compared to children affected by other neurological and psychiatric disorders (non-ASD group, n = 36). All patients were admitted at the Complex Operative Unit of Child Neuropsychiatry, Polyclinic of Bari, Italy. 25(OH)D was quantified by chemiluminescence immunoassay and level defined as: deficiency (<20 ng/mL); insufficiency (20-30); normality (30-100); toxicity (>100). Statistical analysis was performed using SPSS20 (significance < 0.05). The ASD group showed 25(OH)D a mean level significantly lower than control (p = 0.014). Multivariable logistic regression analysis showed an association between ASD and vitamin D deficiency (p = 0.006). The nature of such association is unclear. Vitamin D deficiency may probably act as a risk factor for the development of ASD. Further studies are needed to unravel the role of vitamin D in ASD etiology and investigate its therapeutic potential.

Exploration of the Molecular Mechanism for Lipoprotein Lipase Expression Variations in SH-SY5Y Cells Exposed to Different Doses of Amyloid-Beta Protein

Progressive accumulation of amyloid-β (Aβ) plaques in the brain is a characteristic pathological change in Alzheimer's disease (AD). We previously found the expression of lipoprotein lipase (LPL) was increased in SH-SY5Y cells exposed to low-dose Aβ and decreased in cells with high-dose Aβ exposure, but the molecular mechanism is still unclear. Based on previous studies, the opposite regulation of histone deacetylase2 (HDAC2) and HDAC3 on LPL expression probably explain the above molecular mechanism, in which microRNA-29a and peroxisome proliferator-activated receptor γ (PPARγ) may be involved. This study further revealed the mechanism of HDAC2 and HDAC3 on conversely regulating LPL expression. The results showed that HDAC2 down-regulated microRNA-29a by decreasing histone acetylation (Ace-H3K9) level in its promoter region, subsequently increasing LPL expression directly or through PPARγ/LPL pathway; HDAC3 decreased LPL expression through inhibiting Ace-H3K9 levels in LPL and PPARγ promoter regions and up-regulating microRNA-29a. This study also found that with increasing concentrations of Aβ in cells, HDAC2 and HDAC3 expression were gradually increased, and Ace-H3K9 levels in LPL and PPARγ promoter region regulated by HDAC3 were decreased correspondingly, while Ace-H3K9 levels in microRNA-29a promoter region modulated by HDAC2 were not decreased gradually but presented a U-shaped trend. These may lead to the results that a U-shaped alteration in microRNA-29a expression, subsequently leading to an inverse U-shaped alteration in PPARγ or LPL expression. In conclusion, HDAC2 and HDAC3 at least partly mediate LPL expression variations in different concentrations of Aβ exposed SH-SY5Y cells, in which microRNA-29a and PPARγ are involved, and the histone acetylation level in microRNA-29a promoter region plays a key role.

Prenatal Exposure to Valproic Acid Affects Microglia and Synaptic Ultrastructure in a Brain-Region-Specific Manner in Young-Adult Male Rats: Relevance to Autism Spectrum Disorders

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental conditions categorized as synaptopathies. Environmental risk factors contribute to ASD aetiology. In particular, prenatal exposure to the anti-epileptic drug valproic acid (VPA) may increase the risk of autism. In the present study, we investigated the effect of prenatal exposure to VPA on the synaptic morphology and expression of key synaptic proteins in the hippocampus and cerebral cortex of young-adult male offspring. To characterize the VPA-induced autism model, behavioural outcomes, microglia-related neuroinflammation, and oxidative stress were analysed. Our data showed that prenatal exposure to VPA impaired communication in neonatal rats, reduced their exploratory activity, and led to anxiety-like and repetitive behaviours in the young-adult animals. VPA-induced pathological alterations in the ultrastructures of synapses accompanied by deregulation of key pre- and postsynaptic structural and functional proteins. Moreover, VPA exposure altered the redox status and expression of proinflammatory genes in a brain region-specific manner. The disruption of synaptic structure and plasticity may be the primary insult responsible for autism-related behaviour in the offspring. The vulnerability of specific synaptic proteins to the epigenetic effects of VPA may highlight the potential mechanisms by which prenatal VPA exposure generates behavioural changes.

Inhibition of the pro-inflammatory mediators in rat neutrophils by shanzhiside methyl ester and its acetyl derivative isolated from Barleria prionitis

ETHNOPHARMACOLOGICAL RELEVANCE

The aerial parts of Barleria prionitis Linn. (BP) (Acanthaceae) plant has long been used to treat inflammatory disorders such as toothache, swellings, arthritis and gout.

AIM OF THE STUDY

The purpose of this study was to evaluate the effects of shanzhiside methyl ester (SME), 8-O-acetyl shanzhiside methyl ester (ASME) and iridoid glycosides rich monoterpenoidal fraction (IFBp), isolated from the aerial part of BP, on the pro-inflammatory mediators in stimulated rat neutrophils.

MATERIALS AND METHODS

Rat neutrophils were incubated with or without test drugs. The influence of laboratory isolated and identified SME, ASME and IFBp on the production and release of pro-inflammatory mediators i.e. myeloperoxidase (MPO), elastase, matrix metalloproteinase-9 (MMP-9), interleukin 8 (IL-8), tumor necrosis factor alpha (TNF-α) and leukotriene B4 (LTB4) was evaluated in the formyl-met-leu-phenylalanine (f-MLP) and lipopolysaccharide (LPS) stimulated rat neutrophils using enzyme-linked immunosorbent assay (ELISA) methods. IFBp was also standardized with the high performance thin layer chromatography by simultaneous determination of SME and ASME marker compounds.

RESULTS

SME, ASME and IFBp displayed concentration-dependent inhibitory effects on the MPO, elastase and MMP-9 enzymes release, and IL-8, TNF-α and LTB4 cytokines production in the f-MLP and LPS stimulated rat neutrophils. The content of SME and ASME was found to be 17.32 ± 1.98 and 11.30 ± 1.06% w/w, respectively, in IFBp by HPTLC method.

CONCLUSION

Altogether, the present results suggest that the iridoidal glycosides of BP may be considered as therapeutic strategy against neutrophil-mediated inflammatory diseases. Developed and validated HPTLC method for the standardization of IFBp of BP can be used as a quality control tool for the routine qualitative and quantitative analysis of Barleria species containing SME and/or ASME.

β-Hydroxybutyrate Ameliorates Aβ-Induced Downregulation of TrkA Expression by Inhibiting HDAC1/3 in SH-SY5Y Cells

Tyrosine kinase receptor A (TrkA) plays an important role in the protection of cholinergic neurons in Alzheimer's disease (AD). This study was designed to investigate whether β-hydroxybutyrate (BHB), an endogenous histone deacetylase (HDAC) inhibitor, upregulates the expression of TrkA by affecting histone acetylation in SH-SY5Y cells treated with amyloid β-protein (Aβ). The results showed that BHB ameliorated the reduction of cell vitality and downregulation of TrkA expression induced by Aβ. Furthermore, BHB inhibited the upregulation of HDAC1/2/3 expression and downregulation of histone acetylation (Ace-H3K9 and Ace-H4K12) levels in Aβ-treated cells. The expression of TrkA was upregulated in HDAC1- or 3-silenced SH-SY5Y cells. However, there was no significant difference in TrkA expression between the HDAC2 knockdown and control cells. In conclusion, this study demonstrates that BHB protects against Aβ-induced neurotoxicity in SH-SY5Y cells. The underlying mechanism of the effect may be associated with the upregulation of TrkA expression by inhibiting HDAC1/3.

As a Histone Deacetylase Inhibitor, γ-Aminobutyric Acid Upregulates GluR2 Expression: An In Vitro and In Vivo Study

SCOPE

γ-Aminobutyric acid (GABA) possesses extensive physiological functions and can be directly obtained from foods. GABA-enriched functional foods have been developed and the commercial demands for GABA are increasing. GABA is widely recognized as a central nervous system inhibitory neurotransmitter and plays an important role in some diseases by binding to its receptors. However, some of the functions of GABA are not explained by neurotransmission or GABA receptor pathways. Therefore, this study investigates whether GABA has the potential to inhibit histone deacetylase (HDAC).

METHODS AND RESULTS

It is found that GABA inhibits HDAC1/2/3 expression and upregulates histone acetylation levels (Ace-H3K9/Ace-H4K12) in SH-SY5Y cells (which express GABA receptors), 3T3-L1 cells (which do not express GABA receptors), and the cerebral cortex in mice. Glutamate receptor 2 (GluR2) is a subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor and is implicated in the pathogenesis of some neurological diseases. It is also found that GABA increases GluR2 expression by inhibiting HDAC1/2 but not HDAC3.

CONCLUSION

A novel role for GABA is demonstrated in which it acts as an HDAC inhibitor. The present study expands the horizons for exploring the non-neurotransmitter functions of GABA.

Lipid Hydrolase Enzymes: Pragmatic Prolongevity Targets for Improved Human Healthspan?

Compelling evidence suggests that lipid metabolism, which plays critical roles in fat storage, cell membrane maintenance, and cell signaling, is intricately linked to aging. Lipid hydrolases are important enzymes that catalyze the hydrolysis of more complex lipids into simpler lipids. Diverse interventions targeting lipid hydrolases can prolong or shorten life in model organisms. For example, the genetic removal of or RNAi knockdown against a phospholipase can reduce lifespan in Caenorhabditis elegans, Drosophila melanogaster, and Mus musculus. The removal of lysosomal acid lipase results in premature death in mice, while its overexpression in nematodes generates lean, long-lived individuals. The overexpression or inhibition of diacylglycerol lipase leads to enhanced or reduced longevity, respectively, in both worms and flies. Lifespan can also be extended by knocking down triacylglycerol lipases in yeast, overexpressing fatty acid amide hydrolase in worms, or removing hepatic lipase in a mouse model of coronary disease. Conversely, flies lacking the triacylglycerol lipase Brummer are obese and short lived. Linking sphingolipids and aging, removing the sphingomyelinase inositol phosphosphingolipid phospholipase shortens chronological lifespan in Saccharomyces cerevisiae, while inhibiting an acid sphingomyelinase in worms or inactivating alkaline ceramidase in flies extends lifespan. The clinical potential of manipulating these enzymes is highlighted by the FDA-approved obesity drug orlistat, which is an inhibitor of pancreatic and hepatic lipases that induces weight loss and improves insulin/glucose homeostasis. Additional research is warranted to better understand how these lipid hydrolases impact aging and to determine if clinical interventions targeting them are capable of improving human healthspan.

Neuroepigenetics and Alzheimer's Disease: An Update

Epigenetics is the study of changes in gene expression which may be triggered by both genetic and environmental factors, and independent from changes to the underlying DNA sequence-a change in phenotype without a change in genotype-which in turn affects how cells read genes. Epigenetic changes represent a regular and natural occurrence but can be influenced also by factors such as age, environment, and disease state. Epigenetic modifications can manifest themselves not only as the manner in which cells terminally differentiate, but can have also deleterious effects, resulting in diseases such as cancer. At least three systems including DNA methylation, histone modification, and non-coding RNA (ncRNA)-associated gene silencing are thought to initiate and sustain epigenetic change. For example, in Alzheimer's disease (AD), both genetic and non-genetic factors contribute to disease etiopathology. While over 250 gene mutations have been related to familial AD, less than 5% of AD cases are explained by known disease genes. More than likely, non-genetic factors, probably triggered by environmental factors, are causative factors of late-onset AD. AD is associated with dysregulation of DNA methylation, histone modifications, and ncRNAs. Among the classes of ncRNA, microRNAs (miRNAs) have a well-established regulatory relevance. MicroRNAs are highly expressed in CNS neurons, where they play a major role in neuron differentiation, synaptogenesis, and plasticity. MicroRNAs impact higher cognitive functions, as their functional impairment is involved in the etiology of neurological diseases, including AD. Alterations in the miRNA network contribute to AD disease processes, e.g., in the regulation of amyloid peptides, tau, lipid metabolism, and neuroinflammation. MicroRNAs, both as biomarkers for AD and therapeutic targets, are in the early stages of exploration. In addition, emerging data suggest that altered transcription of long ncRNAs, endogenous, ncRNAs longer than 200 nucleotides, may be involved in an elevated risk for AD.