Characterization of an NF-kappaB-regulated, miRNA-146a-mediated down-regulation of complement factor H (CFH) in metal-sulfate-stressed human brain cells

Epigenetic Mechanisms of Aluminum-Induced Neurotoxicity and Alzheimer's Disease: A Focus on Non-Coding RNAs

Aluminum (Al) is known to induce neurotoxic effects, potentially contributing to Alzheimer's disease (AD) pathogenesis. Recent studies suggest that epigenetic modification may contribute to Al neurotoxicity, although the mechanisms are still debatable. Therefore, the objective of the present study was to summarize existing data on the involvement of epigenetic mechanisms in Al-induced neurotoxicity, especially AD-type pathology. Existing data demonstrate that Al exposure induces disruption in DNA methylation, histone modifications, and non-coding RNA expression in brains. Alterations in DNA methylation following Al exposure were shown to be mediated by changes in expression and activity of DNA methyltransferases (DNMTs) and ten-eleven translocation proteins (TETs). Al exposure was shown to reduce histone acetylation by up-regulating expression of histone deacetylases (HDACs) and impair histone methylation, ultimately contributing to down-regulation of brain-derived neurotrophic factor (BDNF) expression and activation of nuclear factor κB (NF-κB) signaling. Neurotoxic effects of Al exposure were also associated with aberrant expression of non-coding RNAs, especially microRNAs (miR). Al-induced patterns of miR expression were involved in development of AD-type pathology by increasing amyloid β (Aβ) production through up-regulation of Aβ precursor protein (APP) and β secretase (BACE1) expression (down-regulation of miR-29a/b, miR-101, miR-124, and Let-7c expression), increasing in neuroinflammation through NF-κB signaling (up-regulation of miR-9, miR-125b, miR-128, and 146a), as well as modulating other signaling pathways. Furthermore, reduced global DNA methylation, altered histone modification, and aberrant miRNA expression were associated with cognitive decline in Al-exposed subjects. However, further studies are required to evaluate the contribution of epigenetic mechanisms to Al-induced neurotoxicity and/or AD development.

Nuclear factor kappa B (NF-κB) participates in the aluminum-induced down-regulation of miR29a/b1

BACKGROUND

Studies have shown that aluminum (Al) is one of the environmental risk factors leading to Alzheimer's disease (AD), and Al exposure can cause elevated levels of BACE1mRNA, β-secretase (BACE1), and amyloid beta (Aβ) in vivo and in vitro. Previous studies by our research group have shown that this is partly caused by the negative regulation of BACE1 by miRNA29a/b1 (miR29a/b1). Despite the observed the role of nuclear factor kappa B (NF-κB) on many miRNAs, the upstream regulation of NF-κB protein on miR29 remains poorly understood. The purpose of this study was to better define the relationship between NF-κB and miR29a/b1 and the potentially relevant signaling pathways.

METHODS

On the one hand, we constructed the animal model of Al exposure by the intraperitoneal injection of aluminum-maltolate (Al(mal)3) in rats. Conversely, NF- κB inhibitors were added to adrenal phaeochromocytoma (PC12) cells exposed to Al(mal)3.

RESULTS

We verified that NF-κB shows an increasing trend with Al accumulation in the brain of rats, which is accompanied by a downward trend of miR29a/b1. Notably, the suppression of NF-κB significantly increased miR29a/b1 and affected the expression of BACE1mRNA and downstream proteins.

CONCLUSION

Al-induced NF-κB can negatively regulate the expression of miR29a/b1, which then significantly enhances the expression of BACE1 and Aβ plaques.

Intrahippocampal Inoculation of Aβ1-42 Peptide in Rat as a Model of Alzheimer's Disease Identified MicroRNA-146a-5p as Blood Marker with Anti-Inflammatory Function in Astrocyte Cells

Circulating microRNAs (miRNAs) have aroused a lot of interest as reliable blood diagnostic biomarkers of Alzheimer's disease (AD). Here, we investigated the panel of expressed blood miRNAs in response to aggregated Aβ_1-42 peptides infused in the hippocampus of adult rats to mimic events of the early onset of non-familial AD disorder. Aβ_1-42 peptides in the hippocampus led to cognitive impairments associated with an astrogliosis and downregulation of circulating miRNA-146a-5p, -29a-3p, -29c-3p, -125b-5p, and-191-5p. We established the kinetics of expression of selected miRNAs and found differences with those detected in the APP_swe/PS1_dE9 transgenic mouse model. Of note, miRNA-146a-5p was exclusively dysregulated in the Aβ-induced AD model. The treatment of primary astrocytes with Aβ_1-42 peptides led to miRNA-146a-5p upregulation though the activation of the NF-κB signaling pathway, which in turn downregulated IRAK-1 but not TRAF-6 expression. As a consequence, no induction of IL-1β, IL-6, or TNF-α was detected. Astrocytes treated with a miRNA-146-5p inhibitor rescued IRAK-1 and changed TRAF-6 steady-state levels that correlated with the induction of IL-6, IL-1β, and CXCL1 production, indicating that miRNA-146a-5p operates anti-inflammatory functions through a NF-κB pathway negative feedback loop. Overall, we report a panel of circulating miRNAs that correlated with Aβ_1-42 peptides' presence in the hippocampus and provide mechanistic insights into miRNA-146a-5p biological function in the development of the early stage of sporadic AD.

Microglial Activation in Metal Neurotoxicity: Impact in Neurodegenerative Diseases

Neurodegenerative processes encompass a large variety of diseases with different pathological patterns and clinical features, such as Alzheimer's and Parkinson's diseases. Exposure to metals has been hypothesized to increase oxidative stress in brain cells leading to cell death and neurodegeneration. Neurotoxicity of metals has been demonstrated by several in vitro and in vivo experimental studies, and most probably, each metal has its specific pathway to trigger cell death. As a result, exposure to essential metals, such as manganese, iron, copper, zinc, and cobalt, and nonessential metals, including lead, aluminum, and cadmium, perturbs metal homeostasis at the cellular and organism levels leading to neurodegeneration. In this contribution, a comprehensive review of the molecular mechanisms by which metals affect microglia physiology and signaling properties is presented. Furthermore, studies that validate the disruption of microglia activation pathways as an essential mechanism of metal toxicity that can contribute to neurodegenerative disease are also presented and discussed.

The Factor H protein family: The switchers of the complement alternative pathway

The factor H (FH) protein family is emerging as a complex network of proteins controlling the fate of the complement alternative pathway (AP) and dictating susceptibility to a wide range of diseases including infectious, inflammatory, autoimmune, and degenerative diseases and cancer. Composed, in man, of seven highly related proteins, FH, factor H-like 1, and 5 factor H-related proteins, some of the FH family proteins are devoted to down-regulating the AP, while others exert an opposite function by promoting AP activation. Recent findings have provided insights into the molecular mechanisms defining their biological roles and their pathogenicity, illustrating the relevance that the balance between the regulators and the activators within this protein family has in defining the outcome of complement activation on cell surfaces. In this review we will discuss the emerging roles of the factor H protein family, their impact in the complement cascade, and their involvement in the pathogenesis of complement-mediated diseases associated with the AP dysregulation.

Epigenetics: a new warrior against cardiovascular calcification, a forerunner in modern lifestyle diseases

Arterial and aortic valve calcifications are the most prevalent pathophysiological conditions among all the reported cases of cardiovascular calcifications. It increases with several risk factors like age, hypertension, external stimuli, mechanical forces, lipid deposition, malfunction of genes and signaling pathways, enhancement of naturally occurring calcium inhibitors, and many others. Modern-day lifestyle is affected by numerous environmental factors and harmful toxins that impair our health rather than providing benefits. Applying the combinatorial approach or targeting the exact mechanism could be a new strategy for drug designing or attenuating the severity of calcification. Most of the non-communicable diseases are life-threatening; thus, altering the phenotype and not the genotype may reveal the gateway for fighting with upcoming hurdles. Overall, this review summarizes the reason behind the generation of arterial and aortic valve calcification and its related signaling pathways and also the detrimental effects of calcification. In addition, the individual process of epigenetics and how the implementation of this process becomes a novel approach for diminishing the harmful effect of calcification are discussed. Noteworthy, as epigenetics is linked with genetics and environmental factors necessitates further clinical trials for complete and in-depth understanding and application of this strategy in a more specific and prudent manner.

Predicting conversion from mild cognitive impairment to Alzheimer's disease with multimodal latent factors

INTRODUCTION

We studied the ability of latent factor scores to predict conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD) and investigated whether multimodal factor scores improve predictive power, relative to single-modal factor scores.

METHOD

We conducted exploratory factor analyses (EFAs) and confirmatory factor analyses (CFAs) of the baseline data of MCI subjects in the Alzheimer's Disease Neuroimaging Initiative (ADNI) to generate factor scores for three data modalities: neuropsychological (NP), magnetic resonance imaging (MRI), and cerebrospinal fluid (CSF). Factor scores from single or multiple modalities were entered in logistic regression models to predict MCI to AD conversion for 160 ADNI subjects over a 2-year interval.

RESULTS

NP factors attained an area under the curve (AUC) of .80, with a sensitivity of .66 and a specificity of .77. MRI factors reached a comparable level of performance (AUC = .80, sensitivity = .66, specificity = .78), whereas CSF factors produced weaker prediction (AUC = .70, sensitivity = .56, specificity = .79). Combining NP factors with MRI or CSF factors produced better prediction than either MRI or CSF factors alone. Similarly, adding MRI factors to NP or CSF factors produced improvements in prediction relative to NP or CSF factors alone. However, adding CSF factors to either NP or MRI factors produced no improvement in prediction.

CONCLUSIONS

Latent factor scores provided good accuracy for predicting MCI to AD conversion. Adding NP or MRI factors to factors from other modalities enhanced predictive power but adding CSF factors did not.

A disturbed balance between blood complement protective factors (FH, ApoE) and common pathway effectors (C5a, TCC) in acute COVID-19 and during convalesce

A complement effect on homeostasis during infection is determined by both cytotoxic (activate complement component 5 (C5a) terminal cytotoxic complex (TCC)), and cytoprotective elements (complement factor H (FH), as well as apolipoprotein E (ApoE)). Here, we investigated the gap in knowledge in their blood milieu during SARS-CoV-2 infection with respect to the viral burden, level of tissue necrosis, and immunological response. 101 patients hospitalized with a PCR-confirmed diagnosis of COVID-19 had blood collected at H1 (48 h), H2 (3-4 Days), H3 (5-7 days), H4 (more than 7 days up to 93 days). Pre-existing conditions, treatment, the incidence of cerebrovascular events (CVA), a history of deep venous thrombosis (DVT) and pulmonary embolism (PE), and mortality was collected using electronic medical records. Plasma C5a, TCC, FH, and ApoE were considered as a complement milieu. Tissue necrosis (HMGB1, RAGE), non-specific inflammatory responses (IL-6, C-reactive protein), overall viral burden (SARS-CoV-2 spike protein), and specific immune responses (IgG, IgA, IgM directed αS- & N-proteins) were assessed simultaneously. C5a remained elevated across all time points, with the peak at 5-7 days. Studied elements of complement coalesced around three clusters: #0 (↑↑↑C5a, ↑↑TCC, ↓↓ApoE), #1 ↑C5a, ↑TCC, ↑↑↑FH); #2 (↑C5a, ↑TCC, ↑FH, ↑↑↑ApoE). The decline in FH and ApoE was a predictor of death, while TCC and C5a correlated with patient length of stay, APACHE, and CRP. Increased levels of C5a (Δ = 122.64; p = 0.0294; data not shown) and diminished levels of FH (Δ = 836,969; p = 0.0285; data not shown) co-existed with CVA incidence. C5a correlated storngly with blood RAGE and HMGB1, but not with viral load and immunological responsiveness. Remdesivir positively affected FH preservation, while convalescent plasma treatment elevated C5a levels. Three clusters of complement activation demonstrated a various milieu of ApoE & FH vs C5a & TCC in COVID-19 patients. Complement activation is linked to increased necrosis markers but not to viral burden or immune system response.

Genetics and Epigenetics of Spontaneous Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a complex and heterogeneous disease, and there is no effective treatment. Spontaneous ICH represents the final manifestation of different types of cerebral small vessel disease, usually categorized as: lobar (mostly related to cerebral amyloid angiopathy) and nonlobar (hypertension-related vasculopathy) ICH. Accurate phenotyping aims to reflect these biological differences in the underlying mechanisms and has been demonstrated to be crucial to the success of genetic studies in this field. This review summarizes how current knowledge on genetics and epigenetics of this devastating stroke subtype are contributing to improve the understanding of ICH pathophysiology and their potential role in developing therapeutic strategies.

Characterization of an Immortalized Human Microglial Cell Line as a Tool for the Study of Diabetic Retinopathy

The complexity of the retinal structure reflects on the difficulty to describe its composite cell interactions. Microglia is responsible for the immune reaction to inflammatory stimuli during diabetic retinopathy (DR), but most studies still use rodent cells. We characterized a commercially available immortalized human microglial line and tested its susceptibility to inflammation, to study the interactions between the neuro-vascular retinal portions in species-specific models. After checking the expression of microglial markers, we tried lipopolysaccharide (LPS) stimulation and several pro-inflammatory cocktails to select the best combination able to induce a significant M1 (inflammatory) response. We measured M1 induction through the expression of pro- and anti-inflammatory molecules and performed morphologic and functional assays. Marker expression confirmed the human microglial derivation of these cells. Differently from rodents, LPS did not induce a M1 profile. The best pro-inflammatory stimulus was an interleukin-1β + tumor necrosis factor-α + interferon-γ cocktail, which induced morphology changes and increased proliferation, apoptosis, migration, reactive oxygen species, and the expression of inflammatory cytokines and miRNAs. In conclusion, this microglial line proved potentially useful to investigate the cascade of events leading to DR. In perspective, co-culture models involving microvascular cells will help in the understanding of multifaceted interactions of the neurovascular unit.

Sporadic Alzheimer's Disease- and Neurotoxicity-Related microRNAs Affecting Key Events of Tau-Driven Adverse Outcome Pathway Toward Memory Loss

BACKGROUND

A complex network of aging-related homeostatic pathways that are sensitive to further deterioration in the presence of genetic, systemic, and environmental risk factors, and lifestyle, is implicated in the pathogenesis of progressive neurodegenerative diseases, such as sporadic (late-onset) Alzheimer's disease (sAD).

OBJECTIVE

Since sAD pathology and neurotoxicity share microRNAs (miRs) regulating common as well as overlapping pathological processes, environmental neurotoxic compounds are hypothesized to exert a risk for sAD initiation and progression.

METHODS

Literature search for miRs associated with human sAD and environmental neurotoxic compounds was conducted. Functional miR analysis using PathDip was performed to create miR-target interaction networks.

RESULTS

The identified miRs were successfully linked to the hypothetical starting point and key events of the earlier proposed tau-driven adverse outcome pathway toward memory loss. Functional miR analysis confirmed most of the findings retrieved from literature and revealed some interesting findings. The analysis identified 40 miRs involved in both sAD and neurotoxicity that dysregulated processes governing the plausible adverse outcome pathway for memory loss.

CONCLUSION

Creating miR-target interaction networks related to pathological processes involved in sAD initiation and progression, and environmental chemical-induced neurotoxicity, respectively, provided overlapping miR-target interaction networks. This overlap offered an opportunity to create an alternative picture of the mechanisms underlying sAD initiation and early progression. Looking at initiation and progression of sAD from this new angle may open for new biomarkers and novel drug targets for sAD before the appearance of the first clinical symptoms.

The emerging role of noncoding RNAs in neuroinflammation: Implications in pathogenesis and therapeutic approaches

Noncoding RNAs (ncRNAs) are important regulators of gene expression in different cell processes. Due to their ability in monitoring neural development genes, these transcripts confer neurons with the potential to exert broad control over the expression of genes for performing neurobiological functions. Although the change of ncRNA expression in different neurodegenerative diseases has been reviewed elsewhere, only recent evidence drove our attention to unravel the involvement of these molecules in neuroinflammation within these devastating disorders. Remarkably, the interactions between ncRNAs and inflammatory pathways are not fully recognized. Therefore, this review has focused on the interplay between diverse inflammatory pathways and the related ncRNAs, including microRNAs, long noncoding RNAs, and competing endogenous RNAs in Alzheimer's disease, Parkinson's diseases, amyotrophic lateral sclerosis, epilepsy, multiple sclerosis, Huntington's disease, and prion diseases. Providing novel insights in the field of combining biomarkers is a critical step for using them as diagnostic tools and therapeutic targets in clinical settings.

An Emerging Role of miRNAs in Neurodegenerative Diseases: Mechanisms and Perspectives on miR146a

Significance: Advancements in and access to health care have led to unprecedented improvements in the quality of life and increased lifespan of human beings in the past century. However, aging is a significant risk factor for neurodegenerative diseases (NDs). Hence, improved life expectancy has led to an increased incidence of NDs. Despite intense research, effective treatments for NDs remain elusive. The future of neurotherapeutics development depends on effective disease modification strategies centered on carefully scrutinized targets. Recent Advances: As a promising new direction, recent evidence has demonstrated that epigenetic processes modify diverse biochemical pathways, including those related to NDs. Small non-coding RNAs, known as microRNAs (miRNAs), are components of the epigenetic system that alter the expression of target genes at the post-transcriptional level. Critical Issues: miRNAs are expressed abundantly in the central nervous system and are critical for the normal functioning and survival of neurons. Here, we review recent advances in elucidating miRNAs' roles in NDs and discuss their potential as therapeutic targets. In particular, neuroinflammation is a major pathological hallmark of NDs and miR146a is a crucial regulator of inflammation. Future Directions: Finally, we explore the possibilities of developing miR146a as a potential biomarker and therapeutic target where additional research may help facilitate the detection and amelioration of neuroinflammation in NDs. Antioxid. Redox Signal. 35, 580-594.

microRNA-146a-5p, Neurotropic Viral Infection and Prion Disease (PrD)

The human brain and central nervous system (CNS) harbor a select sub-group of potentially pathogenic microRNAs (miRNAs), including a well-characterized NF-kB-sensitive Homo sapiens microRNA hsa-miRNA-146a-5p (miRNA-146a). miRNA-146a is significantly over-expressed in progressive and often lethal viral- and prion-mediated and related neurological syndromes associated with progressive inflammatory neurodegeneration. These include ~18 different viral-induced encephalopathies for which data are available, at least ~10 known prion diseases (PrD) of animals and humans, Alzheimer’s disease (AD) and other sporadic and progressive age-related neurological disorders. Despite the apparent lack of nucleic acids in prions, both DNA- and RNA-containing viruses along with prions significantly induce miRNA-146a in the infected host, but whether this represents part of the host’s adaptive immunity, innate-immune response or a mechanism to enable the invading prion or virus a successful infection is not well understood. Current findings suggest an early and highly interactive role for miRNA-146a: (i) as a major small noncoding RNA (sncRNA) regulator of innate-immune responses and inflammatory signaling in cells of the human brain and CNS; (ii) as a critical component of the complement system and immune-related neurological dysfunction; (iii) as an inducible sncRNA of the brain and CNS that lies at a critical intersection of several important neurobiological adaptive immune response processes with highly interactive associations involving complement factor H (CFH), Toll-like receptor pathways, the innate-immunity, cytokine production, apoptosis and neural cell decline; and (iv) as a potential biomarker for viral infection, TSE and AD and other neurological diseases in both animals and humans. In this report, we review the recent data supporting the idea that miRNA-146a may represent a novel and unique sncRNA-based biomarker for inflammatory neurodegeneration in multiple species. This paper further reviews the current state of knowledge regarding the nature and mechanism of miRNA-146a in viral and prion infection of the human brain and CNS with reference to AD wherever possible.

NF-κB-Induced Upregulation of miR-146a-5p Promoted Hippocampal Neuronal Oxidative Stress and Pyroptosis via TIGAR in a Model of Alzheimer's Disease

Alzheimer’s disease (AD) is a common neurodegenerative disorder that places a heavy burden on patients and society. Hippocampal neuronal loss is a hallmark of AD progression. Therefore, understanding the mechanism underlying hippocampal neuronal death would be of great importance for the diagnosis and treatment of AD. This study aimed to explore the molecular mechanism via which nuclear factor kappa β (NF-κB) promotes hippocampal neuronal oxidative stress and pyroptosis in AD. We collected serum samples from 101 healthy elderly people and 112 patients with AD at the Affiliated Hospital of Kunming University of Science and Technology between January 2017 and January 2020. Commercially available human hippocampal neurons (HHNs) were used to establish an AD model (AD-HHN) following Aβ25–35 treatment. The mRNA expression levels of NF-κB and pyroptosis markers [NLR family pyrin domain-containing 3, caspase-1, interleukin (IL)-1β, and interleukin-18] mRNA and the expression level of miR-146a-5p in the serum samples of patients with AD and AD-HHNs were determined by quantitative reverse transcription polymerase chain reaction. Oxidative stress indices (reactive oxygen species, malondialdehyde, nicotinamide adenine dinucleotide phosphate, superoxide dismutase, glutathione, and catalase) were measured by Enzyme-Linked Immunosorbent Assay (ELISA). The expression of proteins [NF-κB, TP53-induced glycolysis and apoptosis regulator (TIGAR), and pyroptosis markers] was tested by western blotting. The relationship between miR-146a-5p and TIGAR was investigated using a dual luciferase reporter gene assay. We found that NF-κB and miR-146a-5p were highly expressed, while TIGAR was low expressed in patients with AD and AD-HHNs. In addition, there was a significant positive correlation between the expression levels of NF-κB and miR-146a-5p, but a negative correlation between NF-κB mRNA and TIGAR mRNA in patients with AD, as well as miR-146a-5p and TIGAR mRNA in patients with AD. In AD-HNNs, miR-146a-5p targeted and downregulated the expression of TIGAR. Knockdown of NF-κB or overexpression of TIGAR markedly attenuated oxidative stress and pyroptosis in AD-HHNs, while concurrent overexpression of miR-146a-5p inhibited these effects. In conclusion, NF-κB-induced upregulation of miR-146a-5p promoted oxidative stress and pyroptosis in AD-HNNs by targeting TIGAR.

Viral Involvement in Alzheimer's Disease

Alzheimer's disease (AD) is characterized by the presence of β-amyloid plaques (Aβ) and neurofibrillary tangles (NFTs) in the brain. The prevalence of the disease is increasing and is expected to reach 141 million cases by 2050. Despite the risk factors associated with the disease, there is no known causative agent for AD. Clinical trials with many drugs have failed over the years, and no therapeutic has been approved for AD. There is increasing evidence that pathogens are found in the brains of AD patients and controls, such as human herpes simplex virus-1 (HSV-1). Given the lack of a human model, the route for pathogen entry into the brain remains open for scrutiny and may include entry via a disturbed blood-brain barrier or the olfactory nasal route. Many factors can contribute to the pathogenicity of HSV-1, such as the ability of HSV-1 to remain latent, tau protein phosphorylation, increased accumulation of Aβ invivo and in vitro, and repeated cycle of reactivation if immunocompromised. Intriguingly, valacyclovir, a widely used drug for the treatment of HSV-1 and HSV-2 infection, has shown patient improvement in cognition compared to controls in AD clinical studies. We discuss the potential role of HSV-1 in AD pathogenesis and argue for further studies to investigate this relationship.

The Risks of miRNA Therapeutics: In a Drug Target Perspective

RNAi therapeutics have been growing. Patisiran and givosiran, two siRNA-based drugs, were approved by the Food and Drug Administration in 2018 and 2019, respectively. However, there is rare news on the advance of miRNA drugs (another therapeutic similar to siRNA drug). Here we report the existing obstacles of miRNA therapeutics by analyses for resources available in a drug target perspective, despite being appreciated when it began. Only 10 obtainable miRNA drugs have been in clinical trials with none undergoing phase III, while over 60 siRNA drugs are in complete clinical trial progression including two approvals. We mechanically compared the two types of drug and found that their major distinction lay in the huge discrepancy of the target number of two RNA molecules, which was caused by different complementary ratios. One miRNA generally targets tens and even hundreds of genes. We named it “too many targets for miRNA effect” (TMTME). Further, two adverse events from the discontinuation of two miRNA therapeutics were exactly answered by TMTME. In summary, TMTME is inevitable because of the special complementary approach between miRNA and its target. It means that miRNA therapeutics would trigger a series of unknown and unpreventable consequences, which makes it a considerable alternative for application.

MiRNA-15b and miRNA-125b are associated with regional Aβ-PET and FDG-PET uptake in cognitively normal individuals with subjective memory complaints

There is substantial experimental evidence for dysregulation of several microRNA (miRNA) expression levels in Alzheimer's disease (AD). MiRNAs modulate critical brain intracellular signaling pathways and are associated with AD core pathophysiological mechanisms. First, we conducted a real-time quantitative PCR-based pilot study to identify a set of brain-enriched miRNAs in a monocentric cohort of cognitively normal individuals with subjective memory complaints, a condition associated with increased risk of AD. Second, we investigated the impact of age, sex, and the Apolipoprotein E ε4 (APOE ε4) allele, on the identified miRNA plasma concentrations. In addition, we explored the cross-sectional and longitudinal association of the miRNAs plasma concentrations with regional brain metabolic uptake using amyloid-β (Aβ)-positron emission tomography (Aβ-PET) and ¹⁸F-fluorodeoxyglucose-PET (¹⁸F-FDG-PET). We identified a set of six brain-enriched miRNAs-miRNA-125b, miRNA-146a, miRNA-15b, miRNA-148a, miRNA-26b, and miRNA-100. Age, sex, and APOE ε4 allele were not associated with individual miRNA abundance. MiRNA-15b concentrations were significantly lower in the Aβ-PET-positive compared to Aβ-PET-negative individuals. Furthermore, we found a positive effect of the miRNA-15b*time interaction on regional metabolic ¹⁸F-FDG-PET uptake in the left hippocampus. Plasma miRNA-125b concentrations, as well as the miRNA-125b*time interaction (over a 2-year follow-up), were negatively associated with regional Aβ-PET standard uptake value ratio in the right anterior cingulate cortex. At baseline, we found a significantly negative association between plasma miRNA-125b concentrations and ¹⁸F-FDG-PET uptake in specific brain regions. In an asymptomatic at-risk population for AD, we show significant associations between plasma concentrations of miRNA-125b and miRNA-15b with core neuroimaging biomarkers of AD pathophysiology. Our results, coupled with existing experimental evidence, suggest a potential protective anti-Aβ effect of miRNA-15b and a biological link between miRNA-125b and Aβ-independent neurotoxic pathways.

Association of Complement-Related Proteins in Subjects With and Without Second Trimester Gestational Diabetes

INTRODUCTION

Gestational Diabetes Mellitus (GDM) development is related to underlying metabolic syndrome that is associated with elevated complement C3 and C4. Elevated C3 levels have been associated with preeclampsia and the development of macrosomia.

METHODS

This case-control study included 34 pregnant women with GDM and 16 non-diabetic (ND) women in their second trimester. Complement-related proteins were measured and correlated with demographic, biochemical, and pregnancy outcome data.

RESULTS

GDM women were older with a higher BMI (p<0.001); complement C3, C4 and Factor-H were significantly elevated (p=0.001, p=0.05, p=0.01, respectively). When adjusted for age and BMI, Complement C3 (p=0.04) and Factor-H (p=0.04) remained significant. Partial correlation showed significant correlation between C4 with serum alanine aminotransferase (ALT) (p<0.05) and 2^nd term diastolic blood pressure (p<0.05); Factor-H and C-reactive protein (CRP; p<0.05). Pearson bivariate analysis revealed significant correlations between C3, C4, and Factor-H and CRP; p<0.05; C3 and gestational age at delivery (GA; p<0.05); C4 and ALT and second-trimester systolic blood pressure (STBP) (p=0.008 and p<0.05, respectively); Factor-H and glycated hemoglobin (HbA1c) (p<0.05). Regression analysis showed that the elevation of C3 could be accounted for by age, BMI, GA and CRP, with CRP being the most important predictor (p=0.02). C4 elevation could be accounted for by ALT, CRP and STBP. CRP predicted Factor-H elevation.

CONCLUSION

The increased C3, C4 and Factor-H during the second trimester of pregnancy in GDM are not independently associated with GDM; inflammation and high BMI may be responsible for their elevation. The elevation of second trimester C3 in GDM is associated with earlier delivery and further work is needed to determine if this is predictive.

Effects of Myo-inositol Alone and in Combination with Seleno-Lmethionine on Cadmium-Induced Testicular Damage in Mice

BACKGROUND

Cadmium (Cd) impairs gametogenesis and damages the blood-testis barrier.

OBJECTIVE

As the primary mechanism of Cd-induced damage is oxidative stress, the effects of two natural antioxidants, myo-inositol (MI) and seleno-L-methionine (Se), were evaluated in mice testes.

METHODS

Eighty-four male C57 BL/6J mice were divided into twelve groups: 0.9% NaCl (vehicle; 1 ml/kg/day i.p.); Se (0.2 mg/kg/day per os); Se (0.4 mg/kg/day per os); MI (360 mg/kg/day per os); MI plus Se (0.2 mg/kg/day); MI plus Se (0.4 mg/kg/day); CdCl2 (2 mg/kg/day i.p.) plus vehicle; CdCl2 plus MI; CdCl2 plus Se (0.2 mg/kg/day); CdCl2 plus Se (0.4 mg/kg/day); CdCl2 plus MI plus Se (0.2 mg/kg/day); and CdCl2 plus MI plus Se (0.4 mg/kg/day). After 14 days, testes were processed for biochemical, structural and immunohistochemical analyses.

RESULTS

CdCl2 increased iNOS and TNF-α expression and Malondialdehyde (MDA) levels, lowered glutathione (GSH) and testosterone, induced testicular lesions, and almost eliminated claudin-11 immunoreactivity. Se administration at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression, maintained GSH, MDA and testosterone levels, structural changes and low claudin-11 immunoreactivity. MI alone or associated with Se at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression and MDA levels, increased GSH and testosterone levels, ameliorated structural organization and increased claudin-11 patches number.

CONCLUSION

We demonstrated a protective effect of MI, a minor role of Se and an evident positive role of the association between MI and Se on Cd-induced damages of the testis. MI alone or associated with Se might protect testes in subjects exposed to toxicants, at least to those with behavior similar to Cd.

microRNA-146a Signaling in Alzheimer's Disease (AD) and Prion Disease (PrD)

The mouse- and human-brain-resident, nuclear factor kappa B (NF-κB)-regulated, micro RNA-146a-5p (miRNA-146a-5p) is an inducible, 22-nucleotide, single-stranded non-coding RNA (sncRNA) easily detected in several brain and immunological cell types, and an important epigenetic modulator of inflammatory signaling and the innate-immune response in several neurological disorders. Among all studied microRNAs, miRNA-146a-5p (typically referred to as just miRNA-146a) has been well characterized and its pathological function in progressive, age-related, and lethal human inflammatory neurodegenerative disease states is well documented. This communication will review our current understanding of miRNA-146a, its induction by the NF-kB-stimulating actions of inflammatory mediators, including the secretory products of certain microbial species such as viral vectors, and Gram-negative bacteria (such as Bacteroides fragilis) that are normal residents of the human gastrointestinal (GI) tract microbiome, and how miRNA-146a appears to contribute to neuro-pathological, neuro-inflammatory, and altered neuro-immunological aspects of both Alzheimer's disease (AD) and prion disease (PrD).

MicroRNAs in the regulation of cellular redox status and its implications in myocardial ischemia-reperfusion injury

MicroRNAs (miRNAs) are small RNAs that do not encode for proteins and play key roles in the regulation of gene expression. miRNAs are involved in a comprehensive range of biological processes such as cell cycle control, apoptosis, and several developmental and physiological processes. Oxidative stress can affect the expression levels of multiple miRNAs and, conversely, miRNAs may regulate the expression of redox sensors, alter critical components of the cellular antioxidants, interact with the proteasome, and affect DNA repair systems. The number of publications identifying redox-sensitive miRNAs has increased significantly over the last few years, and some miRNA targets such as Nrf2, SIRT1 and NF-κB have been identified. The complex interplay between miRNAs and ROS is discussed together with their role in myocardial ischemia-reperfusion injury and the potential use of circulating miRNAs as biomarkers of myocardial infarction. Detailed knowledge of redox-sensitive miRNAs is needed to be able to effectively use individual compounds or sets of miRNA-modulating compounds to improve the health-related outcomes associated with different diseases.

MicroRNA-146a Is a Wide-Reaching Neuroinflammatory Regulator and Potential Treatment Target in Neurological Diseases

Progressive functional deterioration and loss of neurons underlies neurological diseases and constitutes an important cause of disability and death worldwide. The causes of various types of neurological diseases often share several critical nerve-related cellular mechanisms and pathological features, particularly the neuroinflammatory response in the nervous system. A rapidly growing body of evidence indicates that various microRNAs play pivotal roles in these processes in neurological diseases and might be viable therapeutic targets. Among these microRNAs, microRNA-146a (miR-146a) stands out due to the rapid increase in recent literature on its mechanistic involvement in neurological diseases. In this review, we summarize and highlight the critical role of miR-146a in neurological diseases. MiR-146a polymorphisms are associated with the risk of neurological disease. Alterations in miR-146a expression levels are crucial events in the pathogenesis of numerous neurological diseases that are spatially and temporally diverse. Additionally, the target genes of miR-146a are involved in the regulation of pathophysiological processes in neurological diseases, particularly the neuroinflammatory response. In summary, miR-146a mainly plays a critical role in neuroinflammation during the progression of neurological diseases and might be a prospective biomarker and therapeutic target. Understanding the mechanisms by which miR-146a affects the neuroinflammatory response in different neurological injuries, different cell types, and even different stages of certain neurological diseases will pave the way for its use as a therapeutic target in neurodegenerative diseases.

Crosstalk of MicroRNAs and Oxidative Stress in the Pathogenesis of Cancer

Oxidative stress refers to an imbalance between reactive oxygen species (ROS) generation and body's capability to detoxify the reactive mediators or to fix the relating damage. MicroRNAs are considered to be important mediators that play essential roles in the regulation of diverse aspects of carcinogenesis. Growing studies have demonstrated that the ROS can regulate microRNA biogenesis and expression mainly through modulating biogenesis course, transcription factors, and epigenetic changes. On the other hand, microRNAs may in turn modulate the redox signaling pathways, altering their integrity, stability, and functionality, thus contributing to the pathogenesis of multiple diseases. Both ROS and microRNAs have been identified to be important regulators and potential therapeutic targets in cancers. However, the information about the interplay between oxidative stress and microRNA regulation is still limited. The present review is aimed at summarizing the current understanding of molecular crosstalk between microRNAs and the generation of ROS in the pathogenesis of cancer.

[MicroRNA and their potential role in the pathogenesis of hemorrhagic stroke]

Spontaneous (non-traumatic) intracerebral hemorrhage (ICH), or hemorrhagic stroke, is a common and serious disease with high morbidity and mortality. Current methods of treating hemorrhagic stroke, from conservative to surgical, are insufficient, which justifies the continuation of the study of this condition, including cellular and molecular changes that occur during a stroke. MicroRNAs (miRNAs) are a class of small non-coding RNAs that play an important role in post-transcriptional regulation of gene expression. MicroRNAs are involved in almost all biological processes, including cell proliferation, apoptosis and cell differentiation, and are also key substances in pathophysiological processes in many diseases, and therefore they can be both potential biomarkers and new therapeutic targets in cancer, degenerative and cardiovascular disease. In recent years, a number of studies have been aimed at studying the role of microRNAs in pathophysiological processes in hemorrhagic stroke, such as apoptosis, inflammation, oxidative stress, violation of the blood-brain barrier (BBB) and cerebral edema. The results of the studies demonstrated that changes in miRNA expression may be associated with the prognosis of ICH. In this article, we consider studies related to miRNAs and hemorrhagic stroke, and clarify the complex relationship between them.

Aluminum-induced generation of lipopolysaccharide (LPS) from the human gastrointestinal (GI)-tract microbiome-resident Bacteroides fragilis

Gram-negative bacteria of the human gastrointestinal (GI) tract microbiome: (i) are capable of generating a broad-spectrum of highly neurotoxic, pro-inflammatory and potentially pathogenic molecules; and (ii) these include a highly immunogenic class of amphipathic surface glycolipids known as lipopolysaccharide (LPS). Bacteroides fragilis (B. fragilis), a commensal, Gram negative, non-motile, non-spore forming obligatory anaerobic bacillus, and one of the most abundant bacteria found in the human GI tract, produces a particularly pro-inflammatory and neurotoxic LPS (BF-LPS). BF-LPS: (i) is known to be secreted from the B. fragilis outer membrane into the external-medium; (ii) can damage biophysiological barriers via cleavage of zonula adherens cell-cell adhesion proteins, thereby disrupting both the GI-tract barrier and the blood-brain barrier (BBB); (iii) is able to transit GI-tract barriers into the systemic circulation and cross the BBB into the human CNS; and (iv) accumulates within CNS neurons in neurodegenerative disorders such as Alzheimer's disease (AD). This short communication provides evidence that the incubation of B. fragilis with aluminum sulfate [Al₂(SO₄)₃] is a potent inducer of BF-LPS. The results suggest for the first time that the pro-inflammatory properties of aluminum may not only be propagated by aluminum itself, but by a stimulation in the production of microbiome-derived BF-LPS and other pro-inflammatory pathogenic microbial products normally secreted from human GI-tract-resident microorganisms.

Candidate Genes and MiRNAs Linked to the Inverse Relationship Between Cancer and Alzheimer's Disease: Insights From Data Mining and Enrichment Analysis

The incidence of cancer and Alzheimer’s disease (AD) increases exponentially with age. A growing body of epidemiological evidence and molecular investigations inspired the hypothesis of an inverse relationship between these two pathologies. It has been proposed that the two diseases might utilize the same proteins and pathways that are, however, modulated differently and sometimes in opposite directions. Investigation of the common processes underlying these diseases may enhance the understanding of their pathogenesis and may also guide novel therapeutic strategies. Starting from a text-mining approach, our in silico study integrated the dispersed biological evidence by combining data mining, gene set enrichment, and protein-protein interaction (PPI) analyses while searching for common biological hallmarks linked to AD and cancer. We retrieved 138 genes (ALZCAN gene set), computed a significant number of enriched gene ontology clusters, and identified four PPI modules. The investigation confirmed the relevance of autophagy, ubiquitin proteasome system, and cell death as common biological hallmarks shared by cancer and AD. Then, from a closer investigation of the PPI modules and of the miRNAs enrichment data, several genes (SQSTM1, UCHL1, STUB1, BECN1, CDKN2A, TP53, EGFR, GSK3B, and HSPA9) and miRNAs (miR-146a-5p, MiR-34a-5p, miR-21-5p, miR-9-5p, and miR-16-5p) emerged as promising candidates. The integrative approach uncovered novel miRNA-gene networks (e.g., miR-146 and miR-34 regulating p62 and Beclin1 in autophagy) that might give new insights into the complex regulatory mechanisms of gene expression in AD and cancer.

Addressing Alzheimer's Disease (AD) Neuropathology Using Anti-microRNA (AM) Strategies

Disruptions in multiple neurobiological pathways and neuromolecular processes have been widely implicated in the etiopathology of Alzheimer's disease (AD), a complex, progressive, and ultimately lethal neurological disorder whose current incidence, both domestically and globally, is reaching epidemic proportions. While only a few percent of all AD cases appear to have a strong genetic or familial component, the major form of this disease, known as idiopathic or sporadic AD, displays a multi-factorial pathology and represents one of the most complex and perplexing neurological disorders known. More effective and innovative pharmacological strategies for the successful intervention and management of AD might be expected: (i) to arise from strategic-treatments that simultaneously address multiple interrelated AD targets that are directed at the initiation, development, and/or propagation of this disease and (ii) those that target the "neuropathological core" of the AD process at early or upstream stages of AD. This "Perspectives paper" will review current research involving microRNA (miRNA)-mediated, messenger RNA (mRNA)-targeted gene expression pathways in sporadic AD and address the potential implementation of evolving anti-microRNA (AM) strategies in the amelioration and clinical management of AD. This novel-therapeutic approach: (i) incorporates a system involving the restoration of multiple miRNA-regulated mRNA-targets via the use of selectively-stabilized AM species; and (ii) that via implementation of synthetic AMs, the abundance of only relatively small-families of miRNAs need be modulated or neutralized to re-establish neural-homeostasis in the AD-affected brain. In doing so, these strategic approaches will jointly and interactively address multiple AD-associated processes such as the disruption of synaptic communication, defects in amyloid peptide clearance and amyloidogenesis, tau pathology, deficits in neurotrophic support, alterations in the innate immune response, and the proliferation of neuroinflammatory signaling.

Mixed Diets Reduce the Oxidative Stress of Common Carp (Cyprinus carpio): Based on MicroRNA Sequencing

The rice-fish mode, a mode of ecological aquaculture, has become a popular research topic in recent years. The antioxidant capacity of fish can be affected by the type of diet. Three groups of adult common carp (initial weight 517.8 ± 50 g) were fed earthworm (group A), earthworm + duckweed (group M), and duckweed (group P). The antioxidant capacity of common carp (Cyprinus carpio) was evaluated by histopathological sectioning, antioxidant enzyme activity, and the miRNA transcriptome profile. The pathological changes in group M were lighter than those in groups C and A. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) significantly increased in group M, and the malondialdehyde content (MDA) significantly decreased (p < 0.05). Additionally, nine differentially expressed miRNAs (DEMs) were found between groups A and M, and eight DEMs found between groups P and M were identified in the liver of common carp. Five miRNAs were reported to be related to oxidative stress, including miR-137-3p, miR-143-3p, miR-146a-5p, miR-21-5p, and miR-125b-5p. Compared with group M, all five detected miRNAs were upregulated in group A, and four of the detected miRNAs were upregulated in group P. The targets of the five miRNAs were further predicted via functional analysis. Our study confirmed that omnivorous common carp exhibits stronger antioxidant capacity when feeding on both an animal diet and a plant diet.

Facile synthesis of copper sulfide decorated reduced graphene oxide nanocomposite for high sensitive detection of toxic antibiotic in milk

The development of an effective technique for detecting antibiotic drugs remains a serious task due to their toxicity to public health. For this purpose, herein, we report an electrochemical detection based on Cu₂S nanosphere decorated reduced graphene oxide (RGO@Cu₂S NC) nanocomposite. A sonochemical-assisted method was adopted to prepare the nanocomposite. Subsequently, its morphological, elemental, and crystal structural aspects were analysed. The electrochemical properties were examined in order to ensure the material's suitability in electrocatalytic sensing. RGO@Cu₂S NC affixed screen-printed electrode was found to exhibit tremendous electrocatalytic capability toward chloramphenicol (CAP) reduction. A sensitive and reproducible amperometric CAP sensor was fabricated which was able to detect concentration at the nanomolar level. The method worked well even in real samples (fresh milk samples) and the results are evaluated by HPLC method and amperometric methods.

Aluminum in Neurological and Neurodegenerative Disease

With continuing cooperation from 18 domestic and international brain banks over the last 36 years, we have analyzed the aluminum content of the temporal lobe neocortex of 511 high-quality human female brain samples from 16 diverse neurological and neurodegenerative disorders, including 2 groups of age-matched controls. Temporal lobes (Brodmann areas A20-A22) were selected for analysis because of their availability and their central role in massive information-processing operations including efferent-signal integration, cognition, and memory formation. We used the analytical technique of (i) Zeeman-type electrothermal atomic absorption spectrophotometry (ETAAS) combined with (ii) preliminary analysis from the advanced photon source (APS) hard X-ray beam (7 GeV) fluorescence raster-scanning (XRFR) spectroscopy device (undulator beam line 2-ID-E) at the Argonne National Laboratory, US Department of Energy, University of Chicago IL, USA. Neurological diseases examined were Alzheimer's disease (AD; N = 186), ataxia Friedreich's type (AFT; N = 6), amyotrophic lateral sclerosis (ALS; N = 16), autism spectrum disorder (ASD; N = 26), dialysis dementia syndrome (DDS; N = 27), Down's syndrome (DS; trisomy, 21; N = 24), Huntington's chorea (HC; N = 15), multiple infarct dementia (MID; N = 19), multiple sclerosis (MS; N = 23), Parkinson's disease (PD; N = 27), and prion disease (PrD; N = 11) that included bovine spongiform encephalopathy (BSE; "mad cow disease"), Creutzfeldt-Jakob disease (CJD) and Gerstmann-Straussler-Sheinker syndrome (GSS), progressive multifocal leukoencephalopathy (PML; N = 11), progressive supranuclear palsy (PSP; N = 24), schizophrenia (SCZ; N = 21), a young control group (YCG; N = 22; mean age, 10.2 ± 6.1 year), and an aged control group (ACG; N = 53; mean age, 71.4 ± 9.3 year). Using ETAAS, all measurements were performed in triplicate on each tissue sample. Among these 17 common neurological conditions, we found a statistically significant trend for aluminum to be increased only in AD, DS, and DDS compared to age- and gender-matched brains from the same anatomical region. This is the largest study of aluminum concentration in the brains of human neurological and neurodegenerative disease ever undertaken. The results continue to suggest that aluminum's association with AD, DDS, and DS brain tissues may contribute to the neuropathology of those neurological diseases but appear not to be a significant factor in other common disorders of the human brain and/or CNS.

Aluminum in neurological disease - a 36 year multicenter study

Aluminum is a ubiquitous neurotoxin highly enriched in our biosphere, and has been implicated in the etiology and pathology of multiple neurological diseases that involve inflammatory neural degeneration, behavioral impairment and cognitive decline. Over the last 36 years our group has analyzed the aluminum content of the temporal lobe neocortex of 511 high quality coded human brain samples from 18 diverse neurological and neurodegenerative disorders, including 2 groups of age-matched controls. Brodmann anatomical areas including the inferior, medial and superior temporal gyrus (A20-A22) were selected for analysis: (i) because of their essential functions in massive neural information processing operations including cognition and memory formation; and (ii) because subareas of these anatomical regions are unique to humans and are amongst the earliest areas affected by progressive neurodegenerative disorders such as Alzheimer's disease (AD). Coded brain tissue samples were analyzed using the analytical technique of: (i) Zeeman-type electrothermal atomic absorption spectrophotometry (ETAAS) combined with (ii) an experimental multi-elemental analysis using the advanced photon source (APS) ultra-bright storage ring-generated hard X-ray beam (7 GeV) and fluorescence raster scanning (XRFR) spectroscopy device at the Argonne National Laboratory, US Department of Energy, University of Chicago IL, USA. These data represent the largest study of aluminum concentration in the brains of human neurological and neurodegenerative disease ever undertaken. Neurological diseases examined were AD (N=186), ataxia Friedreich's type (AFT; N=6), amyotrophic lateral sclerosis (ALS; N=16), autism spectrum disorder (ASD; N=26), dialysis dementia syndrome (DDS; N=27), Down's syndrome (DS; trisomy21; N=24), Huntington's chorea (HC; N=15), multiple infarct dementia (MID; N=19), multiple sclerosis (MS; N=23), Parkinson's disease (PD; N=27), prion disease (PrD; N=11) including bovine spongiform encephalopathy (BSE; 'mad cow disease'), Creutzfeldt-Jakob disease (CJD) and Gerstmann-Straussler-Sheinker syndrome (GSS), progressive multifocal leukoencephalopathy (PML; N=11), progressive supranuclear palsy (PSP; N=24), schizophrenia (SCZ; N=21), a young control group (YCG; N=22) and an aged control group (ACG; N=53). Amongst these 18 common neurological conditions and controls we report a statistically significant trend for aluminum to be increased only in AD, DS and DDS compared to age- and gender-matched brains from the same anatomical region. The results continue to suggest that aluminum's association with AD, DDS and DS brain tissues may contribute to the neuropathology of these neurological diseases but appear not to be a significant factor in other common disorders of the human central nervous system (CNS).

Multiple Immune-Inflammatory and Oxidative and Nitrosative Stress Pathways Explain the Frequent Presence of Depression in Multiple Sclerosis

Patients with a diagnosis of multiple sclerosis (MS) or major depressive disorder (MDD) share a wide array of biological abnormalities which are increasingly considered to play a contributory role in the pathogenesis and pathophysiology of both illnesses. Shared abnormalities include peripheral inflammation, neuroinflammation, chronic oxidative and nitrosative stress, mitochondrial dysfunction, gut dysbiosis, increased intestinal barrier permeability with bacterial translocation into the systemic circulation, neuroendocrine abnormalities and microglial pathology. Patients with MS and MDD also display a wide range of neuroimaging abnormalities and patients with MS who display symptoms of depression present with different neuroimaging profiles compared with MS patients who are depression-free. The precise details of such pathology are markedly different however. The recruitment of activated encephalitogenic Th17 T cells and subsequent bidirectional interaction leading to classically activated microglia is now considered to lie at the core of MS-specific pathology. The presence of activated microglia is common to both illnesses although the pattern of such action throughout the brain appears to be different. Upregulation of miRNAs also appears to be involved in microglial neurotoxicity and indeed T cell pathology in MS but does not appear to play a major role in MDD. It is suggested that the antidepressant lofepramine, and in particular its active metabolite desipramine, may be beneficial not only for depressive symptomatology but also for the neurological symptoms of MS. One clinical trial has been carried out thus far with, in particular, promising MRI findings.

The role of the microRNA-146a/complement factor H/interleukin-1β-mediated inflammatory loop circuit in the perpetuate inflammation of chronic temporal lobe epilepsy

Increasing evidence indicates that neuroinflammation plays a crucial role in the pathogenesis of temporal lobe epilepsy (TLE). However, it is unclear how the perpetuate inflammation develops. Some recent studies have suggested the possible involvement of microRNA-146a (miR-146a) in the modulation of inflammatory signaling occurring in TLE. To understand how miR-146a modulates inflammatory signaling in TLE, we investigated the role of interleukin-1β (IL-1β), miR-146a and human complement factor H (CFH) in the perpetuate inflammation in rat models of chronic TLE and U251 cells. We found that enhancive miR-146a could upregulate the expression of IL-1β and downregulate the expression of CFH, whereas reductive miR-146a could downregulate the expression of IL-1β and upregulate the expression of CFH, in hippocampi of chronic TLE rat models. Meanwhile, enhancive miR-146a could increase the abnormal wave forms in the chronic TLE rat models. Additionally, enhancive IL-1β could feedback downregulate the expression of CFH, upregulate the expression of miR-146a and increase the abnormal wave forms in chronic TLE rat models. After CFH gene knockdown in U251 cells, enhancive miR-146a did not upregulate the expression of IL-1β. In summary, this study shows that enhancive miR-146a can upregulate the inflammatory factor IL-1β in chronic TLE by downregulating CFH, and that upregulation of IL-1β plays an important feedback-regulating role in the expression of miR-146a and CFH, forming a miR-146a–CFH–IL-1β loop circuit that initiates a cascade of inflammation and then leads to the perpetuate inflammation in TLE. Therefore, modulation of the miR-146a–CFH–IL-1β loop circuit could be a novel therapeutic target for TLE.

Summary: The microRNA-146a–complement factor H–interleukin-1β loop circuit might initiate a cascade of inflammation, leading to the perpetuate inflammation in temporal lobe epilepsy.

Microbiome-Mediated Upregulation of MicroRNA-146a in Sporadic Alzheimer's Disease

The first indication of a potential mechanistic link between the pathobiology of the human gastrointestinal (GI)-tract microbiome and its contribution to the pathogenetic mechanisms of sporadic Alzheimer's disease (AD) came a scant 4 years ago (1). Ongoing research continues to strengthen the hypothesis that neurotoxic microbial-derived components of the GI tract microbiome can cross aging GI tract and blood-brain barriers and contribute to progressive proinflammatory neurodegeneration, as exemplified by the AD-process. Of central interest in these recent investigations are the pathological roles played by human GI tract resident Gram-negative anaerobic bacteria and neurotropic viruses-two prominent divisions of GI tract microbiome-derived microbiota-which harbor considerable pathogenic potential. It is noteworthy that the first two well-studied microbiota-the GI tract abundant Gram-negative bacteria Bacteroides fragilis and the neurotropic herpes simplex virus-1 both share a final common pathway of NF-κB (p50/p65) activation and microRNA-146a induction with ensuing pathogenic stimulation of innate-immune and neuroinflammatory pathways. These appear to strongly contribute to the inflammation-mediated amyloidogenic neuropathology of AD. This communication: (i) will review recent research contributions that have expanded our understanding of the nature of the translocation of microbiome-derived neurotoxins-across biophysiological barriers; (ii) will assess multiple-recent investigations of the induction of the proinflammatory pathogenic microRNA-146a by these two prominent classes of human microbiota; and (iii) will discuss the role of molecular neurobiology and mechanistic contribution of polymicrobial infections to AD-type neuropathological change.

Turing Revisited: Decoding the microRNA Messages in Brain Extracellular Vesicles for Early Detection of Neurodevelopmental Disorders

The prevention of neurodevelopmental disorders (NDD) of prenatal origin suffers from the lack of objective tools for early detection of susceptible individuals and the long time lag, usually in years, between the neurotoxic exposure and the diagnosis of mental dysfunction. Human data on the effects of alcohol, lead, and mercury and experimental data from animals on developmental neurotoxins and their long-term behavioral effects have achieved a critical mass, leading to the concept of the Developmental Origin of Health and Disease (DOHaD). However, there is currently no way to evaluate the degree of brain damage early after birth. We propose that extracellular vesicles (EVs) and particularly exosomes, released by brain cells into the fetal blood, may offer us a non-invasive means of assessing brain damage by neurotoxins. We are inspired by the strategy applied by Alan Turing (a cryptanalyst working for the British government), who created a first computer to decrypt German intelligence communications during World War II. Given the growing evidence that microRNAs (miRNAs), which are among the molecules carried by EVs, are involved in cell-cell communication, we propose that decrypting messages from EVs can allow us to detect damage thus offering an opportunity to cure, reverse, or prevent the development of NDD. This review summarizes recent findings on miRNAs associated with selected environmental toxicants known to be involved in the pathophysiology of NDD.

Redox regulation of microRNAs in cancer

Dysregulation of microRNAs (miRNAs) has long been implicated in tumorigenesis, whereas the underlying mechanisms remain largely unknown. Oxidative stress is a hallmark of cancer that involved in multiple pathophysiological processes, including the aberrant regulation of miRNAs. Compelling evidences have implied complicated interplay between reactive oxygen species (ROS) and miRNAs. Indeed, ROS induces carcinogenesis through either reducing or increasing the miRNA level, leading to the activation of oncogenes or silence of tumor suppressors, respectively. In turn, miRNAs target ROS productive genes or antioxidant responsive elements to affect cellular redox balance, which contributes to establishing a microenvironment favoring cancer cell growth and metastasis. Both miRNAs and ROS have been identified as potential biomarkers and therapeutic targets in human malignancies, and comprehensive understanding of the molecular events herein will facilitate the development of novel cancer therapeutic strategies.

Stress-induced changes in miRNA biogenesis and functioning

MicroRNAs (miRNAs) are small, noncoding RNAs that play key roles in the regulation of cellular homeostasis in eukaryotic organisms. There is emerging evidence that some of these processes are influenced by various forms of cellular stresses, including DNA damage, pathogen invasion or chronic stress associated with diseases. Many reports over the last decade demonstrate examples of stress-induced miRNA deregulation at the level of transcription, processing, subcellular localization and functioning. Moreover, core miRNA biogenesis proteins and their interactions with partners can be selectively regulated in response to stress signaling. However, little is known about the role of isomiRs and the interactions of miRNA with non-canonical targets in the context of the stress response. In this review, we summarize the current knowledge on miRNA functions under various stresses, including chronic stress and miRNA deregulation in the pathogenesis of age-associated neurodegenerative disorders.

Lipopolysaccharide (LPS) Accumulates in Neocortical Neurons of Alzheimer's Disease (AD) Brain and Impairs Transcription in Human Neuronal-Glial Primary Co-cultures

Several independent laboratories have recently reported the detection of bacterial nucleic acid sequences or bacterial-derived neurotoxins, such as highly inflammatory lipopolysaccharide (LPS), within Alzheimer’s disease (AD) affected brain tissues. Whether these bacterial neurotoxins originate from the gastrointestinal (GI) tract microbiome, a possible brain microbiome or some dormant pathological microbiome is currently not well understood. Previous studies indicate that the co-localization of pro-inflammatory LPS with AD-affected brain cell nuclei suggests that there may be a contribution of this neurotoxin to genotoxic events that support inflammatory neurodegeneration and failure in homeostatic gene expression. In this report we provide evidence that in sporadic AD, LPS progressively accumulates in neuronal parenchyma and appears to preferentially associate with the periphery of neuronal nuclei. Run-on transcription studies utilizing [α-³²P]-uridine triphosphate incorporation into newly synthesized total RNA further indicates that human neuronal-glial (HNG) cells in primary co-culture incubated with LPS exhibit significantly reduced output of DNA transcription products. These studies suggest that in AD LPS may impair the efficient readout of neuronal genetic information normally required for the homeostatic operation of brain cell function and may contribute to a progressive disruption in the read-out of genetic information.

Deficits in the Proline-Rich Synapse-Associated Shank3 Protein in Multiple Neuropsychiatric Disorders

Signaling between neurons in the human central nervous system (CNS) is accomplished through a highly interconnected network of presynaptic and postsynaptic elements essential in the conveyance of electrical and neurochemical information. One recently characterized core postsynaptic element essential to the efficient operation of this complex network is a relatively abundant ~184.7 kDa proline-rich synapse-associated cytoskeletal protein known as Shank3 (SH3-ankyrin repeat domain; encoded at human chr 22q13.33). In this “Perspectives” article, we review and comment on current advances in Shank3 research and include some original data that show common Shank3 deficits in a number of seemingly unrelated human neurological disorders that include sporadic Alzheimer’s disease (AD), autism spectrum disorder (ASD), bipolar disorder (BD), Phelan–McDermid syndrome (PMS; 22q13.3 deletion syndrome), and schizophrenia (SZ). Shank3 was also found to be downregulated in the CNS of the transgenic AD (TgAD) 5x familial Alzheimer’s disease murine model engineered to overexpress the 42 amino acid amyloid-beta (Aβ42) peptide. Interestingly, the application of known pro-inflammatory stressors, such as the Aβ42 peptide and the metal-neurotoxin aluminum sulfate, to human neuronal–glial cells in primary culture resulted in a significant decrease in the expression of Shank3. These data indicate that deficits in Shank3-expression may be one common denominator linking a wide-range of human neurological disorders that exhibit a progressive or developmental synaptic disorganization that is temporally associated with cognitive decline.

Epigenetic modifications of gene expression by lifestyle and environment

Epigenetics oftenly described as the heritable changes in gene expression independent of changes in DNA sequence. Various environmental factors such as nutrition-dietary components, lifestyle, exercise, physical activity, toxins, and other contributing factors remodel the genome either in a constructive or detrimental way. Since epigenetic changes are reversible and nutrition is one of the many epigenetic regulators that modify gene expression without changing the DNA sequence, dietary nutrients and bioactive food components contribute to epigenetic phenomena either by directly suppressing DNA methylation or histone catalyzing enzymes or by changing the availability of substrates required for enzymatic reactions. Diets that contain catechol-dominant polyphenols are reported to suppress enzyme activity and activate epigenetically silenced genes. Furthermore, several dietary nutrients play a crucial role in one-carbon metabolism including folate, cobalamin, riboflavin, pyridoxine, and methionine by directly affecting S-adenosyl-L-methionine. Soy polyphenols block DNA methyltransferases and histone deacetylases to reverse aberrant CpG island methylation. Organosulfur rich compounds such as the sulforaphane found in broccoli appear to normalize DNA methylation and activate miR-140 expression, which represses SOX9 and ALDH1 and decreases tumor growth. The purpose of this short communication is to overview the epigenetic regulatory mechanisms of diet and other environmental factors. We discuss the epigenetic contributions of dietary components with a particular focus on nutritional polyphenols and flavonoids as epigenetic mediators that modify epigenetic tags and control gene expression. These mechanisms provide new insights to better understand the influence of dietary nutrients on epigenetic modifications and gene expression.

The putative role of environmental aluminium in the development of chronic neuropathology in adults and children. How strong is the evidence and what could be the mechanisms involved?

The conceptualisation of autistic spectrum disorder and Alzheimer's disease has undergone something of a paradigm shift in recent years and rather than being viewed as single illnesses with a unitary pathogenesis and pathophysiology they are increasingly considered to be heterogeneous syndromes with a complex multifactorial aetiopathogenesis, involving a highly complex and diverse combination of genetic, epigenetic and environmental factors. One such environmental factor implicated as a potential cause in both syndromes is aluminium, as an element or as part of a salt, received, for example, in oral form or as an adjuvant. Such administration has the potential to induce pathology via several routes such as provoking dysfunction and/or activation of glial cells which play an indispensable role in the regulation of central nervous system homeostasis and neurodevelopment. Other routes include the generation of oxidative stress, depletion of reduced glutathione, direct and indirect reductions in mitochondrial performance and integrity, and increasing the production of proinflammatory cytokines in both the brain and peripherally. The mechanisms whereby environmental aluminium could contribute to the development of the highly specific pattern of neuropathology seen in Alzheimer's disease are described. Also detailed are several mechanisms whereby significant quantities of aluminium introduced via immunisation could produce chronic neuropathology in genetically susceptible children. Accordingly, it is recommended that the use of aluminium salts in immunisations should be discontinued and that adults should take steps to minimise their exposure to environmental aluminium.

Immunosuppressive effects and associated compensatory responses in zebrafish after full life-cycle exposure to environmentally relevant concentrations of cadmium

In natural environments, fish survive in polluted water by cadmium (Cd) throughout their whole life cycle. However, little information is available on Cd toxicity considering a life cycle assessment. The present study investigated effects of environmental levels of cadmium (0, 2.5, and 5μg/L) on immune responses in liver and spleen of zebrafish for 15 weeks, from embryos to sexually maturity. Nitric oxide (NO) levels and iNOS activity declined in liver and spleen of zebrafish exposed to 5μg/L Cd, suggesting an immunosuppressive effect. The result was further supported by the decreased transcriptional levels of proinflammatory cytokines by Cd, such as interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-1β (IL-1β), and tumour necrosis factor-α (TNF-α) in liver. However, a sharp increase in the mRNA levels of these cytokines was observed in spleen of zebrafish exposed to Cd. The increased mRNA expression of these proinflammatory cytokines may be the secondary effect following immunosuppression and just reflect a compensatory mechanism for coping with the decreased immunity, which may explain an increase in mRNA levels and a decrease in iNOS activity in spleen of zebrafish exposed to Cd. In liver, the down-regulated mRNA levels of iNOS paralleled with the decreased iNOS activity, suggesting a synchronous response from a molecular level to a biochemical level. Positive correlations between mRNA expression levels of nuclear transcription factor κB (NF-κB) and proinflammatory cytokines were also observed, suggesting that NF-κB might be required for the protracted induction of inflammatory genes. The corresponding changes in the mRNA levels of the inhibitor of κBα (IκBαa and IκBαb) may form a feedback loop to restore transcriptional activity of NF-κB. Furthermore, splenic ROS levels were increased by 5μg/L Cd, possibly activating NF-κB pathway. Taken together, immunosuppressive effects and tissue-dependent compensatory responses were demonstrated in zebrafish after full life-cycle exposure to environmental levels of Cd, indicating a compromise between survival and immunity.

A critical evaluation of neuroprotective and neurodegenerative MicroRNAs in Alzheimer's disease

Currently, 5.4 million Americans suffer from AD, and these numbers are expected to increase up to 16 million by 2050. Despite tremendous research efforts, we still do not have drugs or agents that can delay, or prevent AD and its progression, and we still do not have early detectable biomarkers for AD. Multiple cellular changes have been implicated in AD, including synaptic damage, mitochondrial damage, production and accumulation of Aβ and phosphorylated tau, inflammatory response, deficits in neurotransmitters, deregulation of the cell cycle, and hormonal imbalance. Research into AD has revealed that miRNAs are involved in each of these cellular changes and interfere with gene regulation and translation. Recent discoveries in molecular biology have also revealed that microRNAs play a major role in post-translational regulation of gene expression. The purpose of this article is to review research that has assessed neuroprotective and neurodegenerative characteristics of microRNAs in brain samples from AD transgenic mouse models and patients with AD.

An Eye on Age-Related Macular Degeneration: The Role of MicroRNAs in Disease Pathology

Age-related macular degeneration (AMD) is the primary cause of blindness in developed countries, and is the third leading cause worldwide. Emerging evidence suggests that beside environmental and genetic factors, epigenetic mechanisms, such as microRNA (miRNA) regulation of gene expression, are relevant to AMD providing an exciting new avenue for research and therapy. MiRNAs are short, non-coding RNAs thought to be imperative for coping with cellular stress. Numerous studies have analyzed miRNA dysregulation in AMD patients, although with varying outcomes. Four studies which profiled dysregulated circulating miRNAs in AMD yielded unique sets, and there is only minimal overlap in ocular miRNA profiling of AMD. Mouse models of AMD, including oxygen-induced retinopathy and laser-induced choroidal neovascularization, showed similarities to some extent with miRNA patterns in AMD. For example, miR-146a is an extensively researched miRNA thought to modulate inflammation, and was found to be upregulated in AMD mice and cellular systems, but also in human AMD retinae and vitreous humor. Similarly, mir-17, miR-125b and miR-155 were dysregulated in multiple AMD mouse models as well as in human AMD plasma or retinae. These miRNAs are thought to regulate angiogenesis, apoptosis, phagocytosis, and inflammation. A promising avenue of research is the modulation of such miRNAs, as the phenotype of AMD mice could be ameliorated with antagomirs or miRNA-mimic treatment. However, before meaningful strides can be made to develop miRNAs as a diagnostic or therapeutic tool, reproducible miRNA profiles need to be established for the various clinical outcomes of AMD.

Integrated analysis neurimmiRs of tilapia (Oreochromis niloticus) involved in immune response to Streptococcus agalactiae, a pathogen causing meningoencephalitis in teleosts

MicroRNAs (miRNAs) are a class of noncoding RNA molecules and play important roles in a wide spectrum of biological processes, including in immune response. Recent years have witnessed considerable amount of research interest in studies on miRNA-mediated modulation gene function during neuroinflammation. Here, we evaluated Streptococcus agalactiae infected tilapia (Oreochromis niloticus) brain for the expression profile of miRNAs, potential functions and their correlation with genes involved in inflammatory pathways. A total of 1981 miRNAs were identified, including in 486 miRNAs which have homologues in the currently available databases and 1945 novel miRNAs. The expression levels of 547 miRNAs were significantly altered at 6 h-48 h post-bacterial infection, and these miRNAs were therefore classified as differentially expressed tilapia miRNAs. Real-time PCR were implemented for 14 miRNAs co-expressed in five samples, and agreement was confirmed between the high-throughput sequencing and real-time PCR data. For the 486 differentially expressed miRNAs target 41,820 genes. GO and KEGG enrichment analysis revealed that some target genes of miRNAs were grouped mainly into the categories of apoptotic, signal pathwayand immune response. This is the first report of comprehensive identification of teleost miRNAs being differentially regulated in brain in normal conditions relating to bacterial infection.