More than fear? Brain activation patterns of dental phobic patients before and after an exposure-based treatment.

Hyperactivation of brain networks conferring defensive mobilization is assumed to underlie inappropriate defensive-preparation in patients with Specific Phobia. However, studies targeting Dental Phobia (DP) yielded quite heterogeneous results and research concerning the effects of exposure treatments on phobic brain activation so far is missing. This functional Magnetic Resonance Imaging (fMRI) study aimed to investigate activation patterns in DP patients during exposure to phobia-related stimuli and the effects of an exposure-based fear treatment on phobia-related activation. Seventeen patients with DP and seventeen non-phobic, healthy controls participated in this fMRI experiment presenting dental-related and neutral auditory and visual stimuli. After completing a short exposure-based CBT program, patients were scanned a second time to illustrate treatment-related changes in brain activation patterns. Pre-treatment fMRI results demonstrate enhanced activation in DP-patients mainly in the precuneus and lateral parietal cortex. Moreover, a small activation focus was observed in the amygdala and anterior cingulate cortex (ACC) as parts of classically fear-related structures. Activation in all these clusters decreased significantly from pre- to post-treatment assessment and in the case of the ACC was correlated with dental fear reduction. Activation changes in the precuneus and lateral parietal cortex suggest a pronounced first-person perspective memory processing including a vivid recall of contextual information from an egocentric perspective triggered by exposure to phobia-related stimuli. Besides a treatment-sensitive hyperactivity of fear-sensitive structures, DP may also be characterized by a disturbed memory retrieval that can be reorganized by successful exposure treatment.

Forensic investigation on a combined death by food aspiration and acute escitalopram intoxication occurred to a psychiatric subject in a nursing home.

Food aspiration is one of the major health risks for elderly people in nursing homes which could lead to death. Moreover, misconducts in pharmacotherapy may represent a potential risk of adverse drug reactions. It is reported here the toxicological evaluation of a combined death by food aspiration and acute escitalopram intoxication of a psychiatric subject, occurred in a nursing home. An 89-year-old man, suffering from dysphagia and Alzheimer's, was resident in a nursing home. He was fed with a liquid diet administered directly in mouth using a syringe. The man was also being treated with escitalopram 10 mg tablet. One evening, after receiving the meal in the usual way, the man complained of sudden illness. Carried to the emergency room, the man died about 3 h later with a diagnosis of cardiogenic shock subsequentially to ab ingestis. The histological findings revealed the presence of exogenous material, probably food, up to the finest bronchial branches. The toxicological examination revealed the presence of escitalopram and its main metabolite, desmethylcitalopram: in the blood 1972 ng/ml and 285 ng/ml, in the brain 4657 ng/g and 1025 ng/g, in the gastric content 2317 ng/g and 423 ng/g, in the lung 21,771 ng/g and 468 ng/g, respectively. The bad practice of the nurses to dissolve the escitalopram tablet in the liquefied food and to administer the therapy with a syringe directly into the mouth emerged thanks this investigation. Following food aspiration, escitalopram was absorbed by inhalation route, reaching high concentrations in blood and tissues. The death occurred due to a combined mechanism between food aspiration and the escitalopram toxic action.

Periodontitis is associated with altered brain structure and function in normal cognition middle-aged and elderly individuals.

BACKGROUND: Numerous studies have proposed that periodontitis is a potential risk factor for Alzheimer's disease. However, the association between periodontitis and brain normal cognition in aged and elderly individuals (NCs) is unclear. Such a link could provide clues to Alzheimer's disease development and strategies for early prevention. OBJECTIVE: To explore the associations between periodontal condition and metrics of both brain structure and function among NCs with the help of multimodal magnetic resonance imaging (MRI). METHODS: High-resolution T1-weighted structural data, resting-state functional-MRI data, and measures of periodontal condition were collected from 40 NCs. Cortical volume, thickness, and area as well as regional homogeneity were calculated with the aid of DPABISurf software. Correlation analyses were then conducted between each imaging metric and periodontal index. RESULTS: Consistent negative correlations were observed between severity of periodontitis (mild, moderate, severe) and cortical volume, area, and thickness, not only in brain regions that took charge of primary function but also in brain regions associated with advanced cognition behavior. Among participants with mild attachment loss (AL) and a shallow periodontal pocket depth (PPD), periodontal index was positively correlated with most measures of brain structure and function, while among participants with severe AL and deep PPD, periodontal index was negatively correlated with measures of brain structure and function (all p < .005 for each hemisphere). CONCLUSIONS: Our results demonstrate that periodontitis is associated with widespread changes in brain structure and function among middle-aged and elderly adults without signs of cognitive decline, which might be a potential risk factor for brain damage.

Periodontitis and brain magnetic resonance imaging markers of Alzheimer's disease and cognitive aging.

INTRODUCTION: We examined the association of clinical, microbiological, and host response features of periodontitis with MRI markers of atrophy/cerebrovascular disease in the Washington Heights Inwood Columbia Aging Project (WHICAP) Ancillary Study of Oral Health. METHODS: We analyzed 468 participants with clinical periodontal data, microbial plaque and serum samples, and brain MRIs. We tested the association of periodontitis features with MRI features, after adjusting for multiple risk factors for Alzheimer's disease/Alzheimer's disease-related dementia (AD/ADRD). RESULTS: In fully adjusted models, having more teeth was associated with lower odds for infarcts, lower white matter hyperintensity (WMH) volume, higher entorhinal cortex volume, and higher cortical thickness. Higher extent of periodontitis was associated with lower entorhinal cortex volume and lower cortical thickness. Differential associations emerged between colonization by specific bacteria/serum antibacterial IgG responses and MRI outcomes. DISCUSSION: In an elderly cohort, clinical, microbiological, and serological features of periodontitis were associated with MRI findings related to ADRD risk. Further investigation of causal associations is warranted.

Do Microplastics Have Neurological Implications in Relation to Schizophrenia Zebrafish Models? A Brain Immunohistochemistry, Neurotoxicity Assessment, and Oxidative Stress Analysis.

The effects of exposure to environmental pollutants on neurological processes are of increasing concern due to their potential to induce oxidative stress and neurotoxicity. Considering that many industries are currently using different types of plastics as raw materials, packaging, or distribution pipes, microplastics (MPs) have become one of the biggest threats to the environment and human health. These consequences have led to the need to raise the awareness regarding MPs negative neurological effects and implication in neuropsychiatric pathologies, such as schizophrenia. The study aims to use three zebrafish models of schizophrenia obtained by exposure to ketamine (Ket), methionine (Met), and their combination to investigate the effects of MP exposure on various nervous system structures and the possible interactions with oxidative stress. The results showed that MPs can interact with ketamine and methionine, increasing the severity and frequency of optic tectum lesions, while co-exposure (MP+Met+Ket) resulted in attenuated effects. Regarding oxidative status, we found that all exposure formulations led to oxidative stress, changes in antioxidant defense mechanisms, or compensatory responses to oxidative damage. Met exposure induced structural changes such as necrosis and edema, while paradoxically activating periventricular cell proliferation. Taken together, these findings highlight the complex interplay between environmental pollutants and neurotoxicants in modulating neurotoxicity.

No genetic causal associations between periodontitis and brain atrophy or cognitive impairment: evidence from a comprehensive bidirectional Mendelian randomization study.

BACKGROUND: Observational studies have explored the relationships of periodontitis with brain atrophy and cognitive impairment, but these findings are limited by reverse causation, confounders and have reported conflicting results. Our study aimed to investigate the causal associations of periodontitis with brain atrophy and cognitive impairment through a comprehensive bidirectional Mendelian randomization (MR) research. METHODS: We incorporated two distinct genome-wide association study (GWAS) summary datasets as an exploration cohort and a replication cohort for periodontitis. Four and eight metrics were selected for the insightful evaluation of brain atrophy and cognitive impairment, respectively. The former involved cortical thickness and surface area, left and right hippocampal volumes, with the latter covering assessments of cognitive performance, fluid intelligence scores, prospective memory, and reaction time for mild cognitive impairment to Alzheimer's disease (AD), Lewy body dementia, vascular dementia and frontotemporal dementia for severe situations. Furthermore, supplementary analyses were conducted to examine the associations between the longitudinal rates of change in brain atrophy and cognitive function metrics with periodontitis. The main analysis utilized the inverse variance weighting (IVW) method and evaluated the robustness of the results through a series of sensitivity analyses. For multiple tests, associations with p-values < 0.0021 were considered statistically significant, while p-values ≥ 0.0021 and < 0.05 were regarded as suggestive of significance. RESULTS: In the exploration cohort, forward and reverse MR results revealed no causal associations between periodontitis and brain atrophy or cognitive impairment, and only a potential causal association was found between AD and periodontitis (IVW: OR = 0.917, 95% CI from 0.845 to 0.995, P = 0.038). Results from the replication cohort similarly corroborated the absence of a causal relationship. In the supplementary analyses, the longitudinal rates of change in brain atrophy and cognitive function were also not found to have causal relationships with periodontitis. CONCLUSIONS: The MR analyses indicated a lack of substantial evidence for a causal connection between periodontitis and both brain atrophy and cognitive impairment.

RNASEH2C c.194G>A is a Chinese-specific founder mutation in three unrelated patients with Aicardi-Goutières syndrome 3.

Biallelic pathogenic variants in RNASEH2C cause Aicardi-Goutières syndrome 3 (AGS3, MIM #610329), a rare early-onset encephalopathy characterized by intermittent unexplained fever, chilblains, irritability, progressive microcephaly, dystonia, spasticity, severe psychomotor retardation and abnormal brain imaging. Currently, approximately 50 individuals with AGS3 and 19 variants in RNASEH2C have been revealed. Here, we reported the novel clinical manifestations and genotypic information of three unrelated Chinese patients with AGS3 caused by pathogenic variants in RNASEH2C. In addition to three novel missense variants (c.101G>A, p.Cys34Tyr; c.401T>A, p.Leu134Gln and c.434G>T, p.Arg145Leu), one missense variant (c.194G>A, p.Gly65Asp) reoccurred in all patients but was completely absent in South Asian and other ethnicities. Our study expanded the variant spectrum of RNASEH2C and identified RNASEH2C c.194G>A as a Chinese-specific founder mutation. The novel phenotypes, including mouth ulcers, hip dysplasia, retarded dentition and hypogonadism, observed in our patients greatly enriched the clinical characteristics of AGS3.

Immuno-epigenetic signature derived in saliva associates with the encephalopathy of prematurity and perinatal inflammatory disorders.

BACKGROUND: Preterm birth is closely associated with a phenotype that includes brain dysmaturation and neurocognitive impairment, commonly termed Encephalopathy of Prematurity (EoP), of which systemic inflammation is considered a key driver. DNA methylation (DNAm) signatures of inflammation from peripheral blood associate with poor brain imaging outcomes in adult cohorts. However, the robustness of DNAm inflammatory scores in infancy, their relation to comorbidities of preterm birth characterised by inflammation, neonatal neuroimaging metrics of EoP, and saliva cross-tissue applicability are unknown. METHODS: Using salivary DNAm from 258 neonates (n = 155 preterm, gestational age at birth 23.28 - 34.84 weeks, n = 103 term, gestational age at birth 37.00 - 42.14 weeks), we investigated the impact of a DNAm surrogate for C-reactive protein (DNAm CRP) on brain structure and other clinically defined inflammatory exposures. We assessed i) if DNAm CRP estimates varied between preterm infants at term equivalent age and term infants, ii) how DNAm CRP related to different types of inflammatory exposure (maternal, fetal and postnatal) and iii) whether elevated DNAm CRP associated with poorer measures of neonatal brain volume and white matter connectivity. RESULTS: Higher DNAm CRP was linked to preterm status (-0.0107 ± 0.0008, compared with -0.0118 ± 0.0006 among term infants; p < 0.001), as well as perinatal inflammatory diseases, including histologic chorioamnionitis, sepsis, bronchopulmonary dysplasia, and necrotising enterocolitis (OR range |2.00 | to |4.71|, p < 0.01). Preterm infants with higher DNAm CRP scores had lower brain volume in deep grey matter, white matter, and hippocampi and amygdalae (ß range |0.185| to |0.218|). No such associations were observed for term infants. Association magnitudes were largest for measures of white matter microstructure among preterms, where elevated epigenetic inflammation associated with poorer global measures of white matter integrity (ß range |0.206| to |0.371|), independent of other confounding exposures. CONCLUSIONS: Inflammatory-related DNAm captures the allostatic load of inflammatory burden in preterm infants. Such DNAm measures complement biological and clinical metrics when investigating the determinants of neurodevelopmental differences.

White matter abnormalities mediate the association between masticatory dysfunction and cognition among older adults.

BACKGROUND: Masticatory parameters, such as reduced number of teeth and posterior contacts, have been shown to be associated with reduced cognitive status. The underlying mechanisms that affect these associations, are however, not well understood. OBJECTIVES: The study aims to investigate the association between masticatory dysfunction and cognition and explore the mediating effect of brain structure. METHODS: In this cross-sectional study, 45 older adults with subjective masticatory dysfunction (mean age 72.3 ± 4.0 years) were included. Mini-Mental State Examination score <25, brain trauma, neurological disease, neurodegenerative disorders, depression or poor Swedish language skills were criteria for exclusion. Cognitive functions (executive function and episodic memory) and masticatory dysfunction defined by functional occluding status (FOS; the number of occluding units and number of remaining teeth) were analysed with partial correlation models. Structural magnetic resonance imaging was performed on 28 feasible participants. Multiple regression analyses were performed to evaluate the predictive value of brain structure and white matter hypointensities (WM-hypo) on cognitive functions. A mediation analysis was applied to assess significant predictor/s of the association between FOS and cognition. RESULTS: Both episodic memory and executive functions were positively correlated with FOS. WM-hypo predicted cognitive status (executive function, p ≤ .01). WM-hypo mediated 66.6% (p = 0.06) of the association between FOS and executive functions. CONCLUSION: Associations between FOS and cognitive functions are reported, where FOS, a potential modifiable risk factor, was related to both episodic memory and executive functions. The mediating effect of WM-hypo on the association between FOS and executive functions highlights the impact of the vascularisation of the brain on the link between mastication and cognition. The present study provides increased knowledge that bridges the gap between masticatory dysfunction and cognition.

Surface Modification of Nanoparticles Enhances Drug Delivery to the Brain and Improves Survival in a Glioblastoma Multiforme Murine Model.

Glioblastoma multiforme (GBM) is the most malignant type of brain tumor and has an extremely poor prognosis. Current treatment protocols lack favorable outcomes, and alternative treatments with superior efficacy are needed. In this study, we demonstrate that loading paclitaxel (PTX) in a polymeric, nanoparticulate delivery system is capable of improving its brain accumulation and therapeutic activity. We independently incorporated two different positively charged surface modifiers, poly(amidoamine) (PAMAM) and poly(ethylenimine) (PEI), onto poly(lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG), PLGA-PEG, nanoparticles (NPs) using a modified nanoprecipitation technique that assures the formation of nanosized particles while exposing the positively charged polymer on the surface. The prepared NPs underwent comprehensive analyses of their size, charge, in vitro permeability against a BBB cell line, and in vivo biodistribution. Our results demonstrated the successful fabrication of positively charged NPs using PAMAM or PEI. Importantly, significant improvement in brain accumulation (in vivo) was associated with NPs containing PAMAM compared to unmodified NPs or NPs containing PEI. Finally, the efficacy of PAMAM-modified NPs loaded with PTX was evaluated with orthotopic human GBM xenografts in a mouse model, and the data demonstrated improved survival and equivalent safety compared to soluble PTX. Our data substantiate the importance of surface chemistry on the magnitude of NP accumulation in the brain and pave the way for further in vivo evaluation of chemotherapeutic drugs against GBM that have previously been overlooked because of their limited ability to cross the BBB.

Differences in Brain Volume by Tooth Loss and Cognitive Function in Older Japanese Adults.

BACKGROUND: We investigated the association between tooth loss and structural brain volume and its mediating effect on the association between tooth loss and cognitive function in older Japanese. METHODS: A cross-sectional study was conducted by using the data of 494 randomly sampled community-dwelling individuals aged 65-84 years living in Tokamachi City, Japan. Total brain volume (TBV), gray matter volume (GMV), white matter volume (WMV), and hippocampal volume (HV) were measured with magnetic resonance imaging. The association of self-reported number of teeth (≥20, 1-19, and 0) with cognitive function assessed with the Japanese version of the Quick Mild Cognitive Impairment screen and structural brain volume was examined. Causal mediation analysis was performed to evaluate the mediating effect of structural brain volume. Age, sex, socioeconomic status, health behavior, comorbid conditions, and total intracranial volume were adjusted. RESULTS: Respondents with no teeth showed lower cognitive function (coefficient = -4.01; 95% confidence interval [CI]: -7.19, -0.82), lower TBV (coefficient = -10.34; 95% CI: -22.84, 2.17), and lower GMV (coefficient = -6.92; 95% CI: -14.84, 0.99) than those with ≥20 teeth (P for trends were 0.003, 0.035, and 0.047, respectively). The number of teeth was not significantly associated with WMV or HV. GMV showed a significant mediating effect on the association between the number of teeth and cognitive function (coefficient = -0.38; 95% CI: -1.14, -0.002, corresponding to 9.0% of the total effect), whereas TBV did not. CONCLUSIONS: GMV was suggested to mediate the relationship between tooth loss and lower cognitive function.

A rare case report of primary Sjögren's syndrome with clinical characteristics similar to those of CLIPPERS.

BACKGROUND: Primary Sjögren's syndrome (pSS) is an autoimmune inflammatory disease characterized by dryness of the eyes, mouth and other mucous membranes. Patients with pSS can also present with extraglandular manifestations, such as pulmonary, kidney and nervous system involvement. Central nervous system (CNS) manifestations have rarely been described in pSS. CASE PRESENTATION: A 33-year-old man was admitted with a one-month history of dizziness, speech disturbance, and walking instability. His brain enhanced magnetic resonance imaging (MRI) showed symmetrical, enhanced "salt-and-pepper-like" speckled lesions in the brainstem, basal ganglia, and subcortical regions, and his diagnosis was considered possible chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS). Further examination revealed that anti-SSA antibody was positive, and the Schirmer test and labial salivary gland histopathology were abnormal, which supported the diagnosis of pSS. CONCLUSION: pSS is a chronic systemic autoimmune disease that involves neurological complications. This case suggests that CNS lesions of pSS can present with clinical and MRI findings similar to those of CLIPPERS.

De novo stop-loss variants in CLDN11 cause hypomyelinating leukodystrophy.

Claudin-11, a tight junction protein, is indispensable in the formation of the radial component of myelin. Here, we report de novo stop-loss variants in the gene encoding claudin-11, CLDN11, in three unrelated individuals presenting with an early-onset spastic movement disorder, expressive speech disorder and eye abnormalities including hypermetropia. Brain MRI showed a myelin deficit with a discrepancy between T1-weighted and T2-weighted images and some progress in myelination especially involving the central and peripheral white matter. Exome sequencing identified heterozygous stop-loss variants c.622T>C, p.(*208Glnext*39) in two individuals and c.622T>G, p.(*208Gluext*39) in one individual, all occurring de novo. At the RNA level, the variant c.622T>C did not lead to a loss of expression in fibroblasts, indicating this transcript is not subject to nonsense-mediated decay and most likely translated into an extended protein. Extended claudin-11 is predicted to form an alpha helix not incorporated into the cytoplasmic membrane, possibly perturbing its interaction with intracellular proteins. Our observations suggest that stop-loss variants in CLDN11 expand the genetically heterogeneous spectrum of hypomyelinating leukodystrophies.

Structural and functional brain changes in X-linked Charcot-Marie-Tooth disease: insights from a multimodal neuroimaging study.

PURPOSE: Brain involvement in X-linked Charcot-Marie-Tooth disease (CMTX) has been previously reported. We studied the brain structural and functional integrity using a multimodal neuroimaging approach in patients with no current central nervous system (CNS) symptoms, in order to further delineate the disease's phenotype. METHODS: Seventeen CMTX patients with no current CNS symptoms and 24 matched healthy controls underwent brain magnetic resonance imaging (MRI). Structural integrity was evaluated performing Gray matter analysis with voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) of diffusion tensor imaging (DTI). Functional integrity was evaluated with resting-state functional MRI (rs-fMRI). RESULTS: Decreased gray matter density was detected in CMTX patients compared to healthy controls in bilateral hippocampus, left thalamus, left postcentral gyrus, left superior parietal lobule, left cerebellum crus I and II, and vermis VI. DTI analysis showed increased fractional anisotropy and radial diffusivity in the right anterior insula and increased axial diffusivity in right cerebellum crus I in CMTX patients. rs-fMRI revealed decreased spontaneous neural activity on left precentral gyrus in patients compared to healthy controls. CONCLUSION: Advanced magnetic resonance (MR) neuroimaging techniques in CMTX patients revealed structural and functional involvement of multiple motor and extra-motor brain areas. MR neuroimaging techniques have the potential to delineate the CNS phenotype of a peripheral neuropathy like CMTX.

Effect of periodontal treatment on preclinical Alzheimer's disease-Results of a trial emulation approach.

INTRODUCTION: We investigated the relationship between periodontal treatment and pre-clinical Alzheimer's disease (AD). METHODS: In this quasi-experimental design, 177 periodontally treated patients from the "Greifswald Approach to Individualized Medicine" cohort, which used the same protocols as the population-based Study of Health in Pomerania TREND (SHIP-TREND), and 409 untreated subjects from SHIP-TREND were analyzed. Subjects were younger than 60 years at the magnetic resonance imaging examination, with a median observation period of 7.3 years. Imaging markers for brain atrophy in late-onset AD and brain aging were used as the outcomes. RESULTS: Robust to sensitivity analyses, periodontal treatment had a favorable effect on AD-related brain atrophy (-0.41; 95% confidence interval: -0.70 to -0.12; P = .0051), which corresponds to a shift from the 50th to the 37th percentile of the outcome distribution. For brain aging, the treatment effect was uncertain. CONCLUSION: Periodontitis is related to pre-clinical AD in our population.

Physiological and Pathological Remodeling of Cerebral Microvessels.

There is growing evidence that the remodeling of cerebral microvessels plays an important role in plastic changes in the brain associated with development, experience, learning, and memory consolidation. At the same time, abnormal neoangiogenesis, and deregulated regulation of microvascular regression, or pruning, could contribute to the pathogenesis of neurodevelopmental diseases, stroke, and neurodegeneration. Aberrant remodeling of microvesselsis associated with blood-brain barrier breakdown, development of neuroinflammation, inadequate microcirculation in active brain regions, and leads to the dysfunction of the neurovascular unit and progressive neurological deficits. In this review, we summarize current data on the mechanisms of blood vessel regression and pruning in brain plasticity and in Alzheimer's-type neurodegeneration. We discuss some novel approaches to modulating cerebral remodeling and preventing degeneration-coupled aberrant microvascular activity in chronic neurodegeneration.

Stroke.

Stroke is a major cause of death and disability globally. Diagnosis depends on clinical features and brain imaging to differentiate between ischaemic stroke and intracerebral haemorrhage. Non-contrast CT can exclude haemorrhage, but the addition of CT perfusion imaging and angiography allows a positive diagnosis of ischaemic stroke versus mimics and can identify a large vessel occlusion target for endovascular thrombectomy. Management of ischaemic stroke has greatly advanced, with rapid reperfusion by use of intravenous thrombolysis and endovascular thrombectomy shown to reduce disability. These therapies can now be applied in selected patients who present late to medical care if there is imaging evidence of salvageable brain tissue. Both haemostatic agents and surgical interventions are investigational for intracerebral haemorrhage. Prevention of recurrent stroke requires an understanding of the mechanism of stroke to target interventions, such as carotid endarterectomy, anticoagulation for atrial fibrillation, and patent foramen ovale closure. However, interventions such as lowering blood pressure, smoking cessation, and lifestyle optimisation are common to all stroke subtypes.

EV71 infection induces neurodegeneration via activating TLR7 signaling and IL-6 production.

As a neurotropic virus, human Enterovirus 71 (EV71) infection causes hand-foot-and-mouth disease (HFMD) and may develop severe neurological disorders in infants. Toll-like receptor 7 (TLR7) acts as an innate immune receptor and is also a death receptor in the central nervous system (CNS). However, the mechanisms underlying the regulation of TLR7-mediated brain pathogenesis upon EV71 infection remain largely elusive. Here we reveal a novel mechanism by which EV71 infects astrocytes in the brain and induces neural pathogenesis via TLR7 and interleukin-6 (IL-6) in C57BL/6 mice and in human astroglioma U251 cells. Upon EV71 infection, wild-type (WT) mice displayed more significant body weight loss, higher clinical scores, and lower survival rates as compared with TLR7-/- mice. In the cerebral cortex of EV71-infected mice, neurofilament integrity was disrupted, and inflammatory cell infiltration and neurodegeneration were induced in WT mice, whereas these were largely absent in TLR7-/- mice. Similarly, IL-6 production, Caspase-3 cleavage, and cell apoptosis were significantly higher in EV71-infected WT mice as compared with TLR7-/- mice. Moreover, EV71 preferentially infected and induced IL-6 in astrocytes of mice brain. In U251 cells, EV71-induced IL-6 production and cell apoptosis were suppressed by shRNA-mediated knockdown of TLR7 (shTLR7). Moreover, in the cerebral cortex of EV71-infected mice, the blockade of IL-6 with anti-IL-6 antibody (IL-6-Ab) restored the body weight loss, attenuated clinical scores, improved survival rates, reduced the disruption of neurofilament integrity, decreased cell apoptotic induction, and lowered levels of Caspase-3 cleavage. Similarly, in EV71-infected U251 cells, IL-6-Ab blocked EV71-induced IL-6 production and cell apoptosis in response to viral infection. Collectively, it's exhibited TLR7 upregulation, IL-6 induction and astrocytic cell apoptosis in EV71-infected human brain. Taken together, we propose that EV71 infects astrocytes of the cerebral cortex in mice and human and triggers TLR7 signaling and IL-6 release, subsequently inducing neural pathogenesis in the brain.

Electrostatic interactions at the five-fold axis alter heparin-binding phenotype and drive enterovirus A71 virulence in mice.

Enterovirus A71 (EV-A71) causes hand, foot and mouth disease epidemics with neurological complications and fatalities. However, the neuropathogenesis of EV-A71 remains poorly understood. In mice, adaptation and virulence determinants have been mapped to mutations at VP2-149, VP1-145 and VP1-244. We investigate how these amino acids alter heparin-binding phenotype and shapes EV-A71 virulence in one-day old mice. We constructed six viruses with varying residues at VP1-98, VP1-145 (which are both heparin-binding determinants) and VP2-149 (based on the wild type 149K/98E/145Q, termed KEQ) to generate KKQ, KKE, KEE, IEE and IEQ variants. We demonstrated that the weak heparin-binder IEE was highly lethal in mice. The initially strong heparin-binding IEQ variant acquired an additional mutation VP1-K244E, which confers weak heparin-binding phenotype resulting in elevated viremia and increased virus antigens in mice brain, with subsequent high virulence. IEE and IEQ-244E variants inoculated into mice disseminated efficiently and displayed high viremia. Increasing polymerase fidelity and impairing recombination of IEQ attenuated the virulence, suggesting the importance of population diversity in EV-A71 pathogenesis in vivo. Combining in silico docking and deep sequencing approaches, we inferred that virus population diversity is shaped by electrostatic interactions at the five-fold axis of the virus surface. Electrostatic surface charges facilitate virus adaptation by generating poor heparin-binding variants for better in vivo dissemination in mice, likely due to reduced adsorption to heparin-rich peripheral tissues, which ultimately results in increased neurovirulence. The dynamic switching between heparin-binding and weak heparin-binding phenotype in vivo explained the neurovirulence of EV-A71.

Expanding the KIF4A-associated phenotype.

Kinesin super family (KIF) genes encode motor kinesins, a family of evolutionary conserved proteins, involved in intracellular trafficking of various cargoes. These proteins are critical for various physiological processes including neuron function and survival, ciliary function and ciliogenesis, and cell-cycle progression. Recent evidence suggests that alterations in motor kinesin genes can lead to a variety of human diseases, including monogenic disorders. Neuropathies, impaired higher brain functions, structural brain abnormalities and multiple congenital anomalies (i.e., renal, urogenital, and limb anomalies) can result from pathogenic variants in many KIF genes. We expand the phenotype associated with KIF4A variants from developmental delay and intellectual disability with or without epilepsy to a congenital anomaly phenotype with hydrocephalus and various brain anomalies at the more severe end of phenotypic manifestations. Additional anomalies of the kidneys and urinary tract, congenital lymphedema, eye, and dental anomalies seem to be variably associated and overlap with clinical signs observed in other kinesinopathies. Caution still applies to missense variants, but hopefully, future work will further establish genotype-phenotype correlations in a larger number of patients and functional studies may give further insights into the complex function of KIF4A.