Progress on low susceptibility mechanisms of transmissible spongiform encephalopathies

Transmissible spongiform encephalopathies （TSEs）, also known as prion diseases, are a group of fatal neurodegenerative diseases detected in a wide range of mammalian species. The ＂protein-only＂ hypothesis of TSE suggests that prions are transmissible particles devoid of nucleic acid and the primary pathogenic event is thought to be the conversion of cellular prion protein （PrPc） into the disease-associated isoform （prpSc）. According to susceptibility to TSEs, animals can be classified into susceptible species and low susceptibility species. In this review we focus on several species with low susceptibility to TSEs： dogs, rabbits, horses and buffaloes. We summarize recent studies into the characteristics of low susceptibility regarding protein structure, and biochemical and genetic properties.

New perspectives for mesenchymal stromal cells as an adjuvant therapy for infectious disease-associated encephalopathies

Knowledge of the mechanisms that trigger infection-related encephalopathies is still very limited and cell therapies are one of the most promising alternatives for neurodegenerative diseases,and its application in infectious diseases can be of great relevance.Mesenchymal stromal cells are cells with great immunomodulatory potential;therefore,their use in clinical and preclinical studies in a variety of diseases,including central nervous system diseases,increased in the last decade.Mesenchymal stromal cells can exert their beneficial effects through several mechanisms,such as direct cell contact,through surface receptors,and also through paracrine or endocrine mechanisms.The paracrine mechanism is widely accepted by the scientific community and involves the release of soluble factors,which include cytokines,chemokines and trophic factors,and extracellular vesicles.This mini review discusses mesenchymal stromal cells mechanisms of action in neurological disorders,the neuroinflammatory process that takes place in the brain as a result of peripheral inflammation and changes in the brain’s cellular scenario as a common factor in central nervous system diseases,and mesenchymal stromal cells therapy in encephalopathies.Mesenchymal stromal cells have been shown to act in neuroinflammation processes,leading to improved survival and mitigating behavioral damage.More recently,these cells have been tested in preclinical models of infectious diseases-associated encephalopathies(e.g.,cerebral malaria and sepsis associated encephalopathy)and have shown satisfactory results.

A Rapid Bioassay for Classical and L-Type Bovine Spongiform Encephalopathies

The rapid detection of infectivity of several agents that cause Creutzfeldt-Jakob disease has previously been achieved by assaying for deposits of abnormal prion protein (PrPSc) in follicular dendritic cells in the spleens of transgenic mice carrying the human prion protein gene. In this study, transgenic mice expressing the bovine prion protein were inoculated intraperitoneally with classical (C-type) or atypical L-type bovine spongiform encephalopathies (BSE). Proteinase-resistant PrPSc were detected in the spleens of all transgenic mice at 75 days after inoculation with both types of BSE. Infectivity in PrPSc-positive spleens of the transgenic mice revealed that prions of C- and L-type BSE replicated. These results suggest that bioassay system by the transgenic mice could be useful for the rapid detection of BSE infectivity with discriminating between C- and L-type BSEs.

Epileptic Encephalopathies in Infants and Children: Study of Clinico-Electroencephalographic Spectrum in a Tertiary Hospital in Bangladesh

Background: The epileptic encephalopathies collectively exact an immense personal, medical, and financial toll on the affected children, their families, and the healthcare system. Objective: This study was aimed to delineate the clinical spectrum of patients with Epileptic encephalopathies (EEs) and classify them under various epileptic syndromes. Methods: This was a cross-sectional study that was carried out in the department of Neurophysiology of the National Institute of Neurosciences and Hospital, Bangladesh from July 2016 to June 2019. Children with recurrent seizures which were difficult to control and associated with developmental arrest or regression in absence of a progressive brain pathology were considered to be suffering from EE. Children under 12 years of age fulfilling the inclusion criteria were enrolled in the study. These patients were evaluated clinically and Electroencephalography (EEG) was done in all children at presentation. Based on the clinical profile and EEG findings the patients were categorized under various epileptic syndromes according to International League Against Epilepsy (ILAE) classification 2010. Results: A total of 1256 children under 12 years of age were referred to the Neurophysiology Department. Among them, 162 (12.90%) fulfilled the inclusion criteria. Most of the patients were male (64.2%) and below 1 year (37.7%) of age. The majority (56.8%) were delivered at the hospital and 40.1% had a history of perinatal asphyxia. Development was age-appropriate before the onset of a seizure in 38.9% of cases. Most (53.7%) of the patients had seizure onset within 3 months of age. Categorization of Epileptic syndromes found that majority had West Syndrome (WS) (37.65%) followed by Lennox-Gastaut syndrome (LGS) (22.22%), Otahara syndrome (11.73%), Continuous spike-and-wave during sleep (CSWS) (5.66%), Myoclonic astatic epilepsy (MAE) (4.94%), Early myoclonic encephalopathy (EME) (3.7%), Dravet syndrome (3.7%) and Landau-Kleffner syndrome (LKS) (1.23%). 9.26% of syndromes were unclassified. Conclusion: EEG was found to be a useful tool in the evaluation of Epileptic encephalopathies. The clinico-electroencephalographic features are age-related. Their recognition and appropriate management are critical.

Does MgSO_(4) protect the preterm brain?Dissecting its role in the pathophysiology of hypoxic ischemic encephalopathy

Mitigating preterm encephalopathy continues to be one of the greatest challenges in perinatal medicine.Preterm encephalopathy is associated with high mortality,serious morbidity,and significant socio-economic impacts on the individuals,their families,and public health sectors and welfare systems that last a lifetime.The cost of disability associated with preterm brain injury continues to rise.Prevention of this injury,and disability,would significantly reduce this socioeconomic burden.

Connecting cellular mechanisms and extracellular vesicle cargo in traumatic brain injury

Traumatic brain injury is followed by a cascade of dynamic and complex events occurring at the cellular level. These events include: diffuse axonal injury, neuronal cell death, blood-brain barrier break down, glial activation and neuroinflammation, edema, ischemia, vascular injury, energy failure, and peripheral immune cell infiltration. The timing of these events post injury has been linked to injury severity and functional outcome. Extracellular vesicles are membrane bound secretory vesicles that contain markers and cargo pertaining to their cell of origin and can cross the blood-brain barrier. These qualities make extracellular vesicles intriguing candidates for a liquid biopsy into the pathophysiologic changes occurring at the cellular level post traumatic brain injury. Herein, we review the most commonly reported cargo changes in extracellular vesicles from clinical traumatic brain injury samples. We then use knowledge from animal and in vitro models to help infer what these changes may indicate regrading cellular responses post traumatic brain injury. Future research should prioritize labeling extracellular vesicles with markers for distinct cell types across a range of timepoints post traumatic brain injury.

Classical bovine spongiform encephalopathy and chronic wasting disease:two sides of the prion coin

Transmissible spongiform encephalopathies(TSEs)are a group of progressive and ultimately fatal neurologic diseases of man and animals,all resulting from the propagated misfolding of the host's normal cellular prion protein.These diseases can be spontaneous,heritable,anthropogenic/iatrogenic,or in some cases horizontally transmissible,and include such notable TSEs as bovine spongiform encephalopathy(BSE)of cattle and chronic wasting disease(CWD)of cervids.Although they are both unequivocally protein misfolding disorders,they differ markedly in their pathogenesis,transmissibility,and zoonotic potential.While the BSE epidemic has largely abated over the past three decades following global feed bans on ruminant meat and bone meal,CWD,which is readily transmitted through various forms of excreta,has rapidly expanded from its original endemic zone to encompass much of North America,along with recently identified foci in Scandinavia.Most importantly,although the classical form of BSE has proven transmissible to humans consuming contaminated beef or beef products,so far there have been no conclusive reports on the zoonotic transmission of cWD to humans.The underlying basis for these differences-whether host or agent directed-are not well understood,though may be due to inherent differences in the three-dimensional structure of the misfolded BSE or CWD prion proteins or the expression levels and tissue distribution of respective cellular prion proteins.With the uncontrolled geographic spread of CWD,it is imperative that we improve our understanding of the factors governing prion disease pathogenesis,transmission,and zoonotic potential.

Subdural effusion associated with COVID-19 encephalopathy: A case report

BACKGROUND The precise mechanism by which severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)impacts the central nervous system remains unclear,with manifestations spanning from mild symptoms(e.g.,olfactory and gustatory deficits,hallucinations,and headache)to severe complications(e.g.,stroke,seizures,encephalitis,and neurally demyelinating lesions).The occurrence of single-pass subdural effusion,as described below,is extremely rare.CASE SUMMARY A 56-year-old male patient presented with left-sided limb weakness and slurred speech as predominant clinical symptoms.Through comprehensive imaging and diagnostic assessments,he was diagnosed with cerebral infarction complicated by hemorrhagic transformation affecting the right frontal,temporal,and parietal regions.In addition,an intracranial infection with SARS-CoV-2 was identified during the rehabilitation process;consequently,an idiopathic subdural effusion developed.Remarkably,the subdural effusion underwent absorption within 6 d,with no recurrence observed during the 3-month follow-up.CONCLUSION Subdural effusion is a potentially rare intracranial complication associated with SARS-CoV-2 infection.

Magnetic resonance imaging scanning susceptibility weighted imaging sequences in the diagnosis and prognostic evaluation of neonatal hypoxic-ischemic encephalopathy

BACKGROUND Magnetic resonance imaging(MRI)scanning with susceptibility weighted imaging(SWI)sequences plays a significant role in the diagnosis and prognostic evaluation of neonatal hypoxic-ischemic encephalopathy(HIE).AIM To observe the role of MRI multi-parameter quantitative indexes in the diagnosis of neonatal HIE.METHODS The imaging data from 23 cases of neonatal HIE admitted to the Imaging Department of Ganyu District People's Hospital of Lianyungang City and 23 neonates without HIE admitted during the same period were analyzed retrospectively from August,2021 to December,2023.The results of clinical judgment were compared with the results of computed tomography(CT)and MRI examinations.RESULTS The degree of cerebral edema(more than moderate),the number of damaged brain regions(>2),the number of cerebral hemorrhages(>2),and the percentage of small venous dilatation detected were higher in MRI than in CT examination,and the differences were statistically significant(P<0.05).The total area of the largest region of cerebral damage and of cerebral hemorrhage observed by MRI examination were significantly larger than those of CT examination(P<0.01).Multiparametric quantitative MRI combined with diffusion weighted imaging and SWI had higher sensitivity and accuracy than CT diagnosis,and the difference was statistically significant(P<0.05).The difference in the specificity of the two modes of diagnosis was not significant(P>0.05).CONCLUSION The use of MRI multi-parameter quantitative indexes can accurately diagnose and evaluate neonatal HIE.

Transplantation of human placental chorionic plate-derived mesenchymal stem cells for repair of neurological damage in neonatal hypoxic-ischemic encephalopathy

Neonatal hypoxic-ischemic encephalopathy is often associated with permanent cerebral palsy,neurosensory impairments,and cognitive deficits,and there is no effective treatment for complications related to hypoxic-ischemic encephalopathy.The therapeutic potential of human placental chorionic plate-derived mesenchymal stem cells for various diseases has been explored.However,the potential use of human placental chorionic plate-derived mesenchymal stem cells for the treatment of neonatal hypoxic-ischemic encephalopathy has not yet been investigated.In this study,we injected human placental chorionic plate-derived mesenchymal stem cells into the lateral ventricle of a neonatal hypoxic-ischemic encephalopathy rat model and observed significant improvements in both cognitive and motor function.Protein chip analysis showed that interleukin-3 expression was significantly elevated in neonatal hypoxic-ischemic encephalopathy model rats.Following transplantation of human placental chorionic plate-derived mesenchymal stem cells,interleukin-3 expression was downregulated.To further investigate the role of interleukin-3 in neonatal hypoxic-ischemic encephalopathy,we established an in vitro SH-SY5Y cell model of hypoxic-ischemic injury through oxygen-glucose deprivation and silenced interleukin-3 expression using small interfering RNA.We found that the activity and proliferation of SH-SY5Y cells subjected to oxygen-glucose deprivation were further suppressed by interleukin-3 knockdown.Furthermore,interleukin-3 knockout exacerbated neuronal damage and cognitive and motor function impairment in rat models of hypoxic-ischemic encephalopathy.The findings suggest that transplantation of hpcMSCs ameliorated behavioral impairments in a rat model of hypoxic-ischemic encephalopathy,and this effect was mediated by interleukin-3-dependent neurological function.

Fecal microbiota transplantation in the treatment of hepatic encephalopathy:A perspective

Due to its complex pathogenesis,treatment of hepatic encephalopathy(HE)continues to be a therapeutic challenge.Of late,gut microbiome has garnered much attention for its role in the pathogenesis of various gastrointestinal and liver diseases and its potential therapeutic use.New evidence suggests that gut micro-biota plays a significant role in cerebral homeostasis.Alteration in the gut microbiota has been documented in patients with HE in a number of clinical and experimental studies.Research on gut dysbiosis in patients with HE has opened newer therapeutic avenues in the form of probiotics,prebiotics and the latest fecal microbiota transplantation(FMT).Recent studies have shown that FMT is safe and could be effective in improving outcomes in advanced liver disease patients presenting with HE.However,questions over the appropriate dose,duration and route of administration for best treatment outcome remains unsettled.

Role of fecal microbiota transplant in management of hepatic encephalopathy: Current trends and future directions

Fecal microbiota transplantation(FMT)offers a potential treatment avenue for hepatic encephalopathy(HE)by leveraging beneficial bacterial displacement to restore a balanced gut microbiome.The prevalence of HE varies with liver disease severity and comorbidities.HE pathogenesis involves ammonia toxicity,gut-brain communication disruption,and inflammation.FMT aims to restore gut microbiota balance,addressing these factors.FMT's efficacy has been explored in various conditions,including HE.Studies suggest that FMT can modulate gut microbiota,reduce ammonia levels,and alleviate inflammation.FMT has shown promise in alcohol-associated,hepatitis B and C-associated,and non-alcoholic fatty liver disease.Benefits include improved liver function,cognitive function,and the slowing of disease progression.However,larger,controlled studies are needed to validate its effectiveness in these contexts.Studies have shown cognitive improvements through FMT,with potential benefits in cirrhotic patients.Notably,trials have demonstrated reduced serious adverse events and cognitive enhancements in FMT arms compared to the standard of care.Although evidence is promising,challenges remain:Limited patient numbers,varied dosages,administration routes,and donor profiles.Further large-scale,controlled trials are essential to establish standardized guidelines and ensure FMT's clinical applications and efficacy.While FMT holds potential for HE management,ongoing research is needed to address these challenges,optimize protocols,and expand its availability as a therapeutic option for diverse hepatic conditions.

Can rifaximin for hepatic encephalopathy be discontinued during broad-spectrum antibiotic treatment?

Hepatic encephalopathy(HE)is a formidable complication in patients with decompensated cirrhosis,often necessitating the administration of rifaximin(RFX)for effective management.RFX,is a gut-restricted,poorly-absorbable oral rifamycin derived antibiotic that can be used in addition to lactulose for the secondary prophylaxis of HE.It has shown notable reductions in infection,hospital readmission,duration of hospital stay,and mortality.However,limited data exist about the concurrent use of RFX with broad-spectrum antibiotics,because the patients are typically excluded from studies assessing RFX efficacy in HE.A pharmacist-driven quasi-experimental pilot study was done to address this gap.They argue against the necessity of RFX in HE during broad-spectrum antibiotic treatment,particularly in critically ill patients in intensive care unit(ICU).The potential for safe RFX discontinuation without adverse effects is clearly illuminated and valuable insight into the optimization of therapeutic strategies is offered.The findings also indicate that RFX discontinuation during broadspectrum antibiotic therapy was not associated with higher rates of delirium or coma,and this result remained robust after adjustment in multivariate analysis.Furthermore,rates of other secondary clinical and safety outcomes,including ICU mortality and 48-hour changes in vasopressor requirements,were comparable.However,since the activity of RFX is mainly confined to the modulation of gut microbiota,its potential utility in patients undergoing extensive systemic antibiotic therapy is debatable,given the overlapping antibiotic activity.Further,this suggests that the action of RFX on HE is class-specific(related to its activity on gut microbiota),rather than drug-specific.A recent double-blind randomized controlled(ARiE)trial provided further evidence-based support for RFX withdrawal in critically ill cirrhotic ICU patients receiving broad-spectrum antibiotics.Both studies prompt further discussion about optimal therapeutic strategy for patients facing the dual challenge of HE and systemic infections.Despite these compelling results,both studies have limitations.A prospective,multi-center evaluation of a larger sample,with placebo control,and comprehensive neurologic evaluation of HE is warranted.It should include an exploration of longer-term outcome and the impact of this protocol in non-critically ill liver disease patients.

Fetal Head Compression: Its Possible Role in Neurologic Injury

It is widely assumed that fetal ischemic brain injury during labor derives almost exclusively from severe, systemic hypoxemia with marked neonatal depression and acidemia. Severe asphyxia, however, is one of several causes of perinatal neurological injury and may not be the most common;most neonates diagnosed with hypoxic-ischemic encephalopathy do not have evidence of severe asphyxia. Sepsis, direct brain trauma, and drug or toxin exposure account for some cases, while mechanical forces of labor and delivery that increase fetal intracranial pressure sufficiently to impair brain perfusion may also contribute. Because of bony compliance and mobile suture lines, the fetal skull changes shape and redistributes cerebrospinal fluid during labor according to constraints imposed by contractions, and bony and soft tissue elements of the birth canal as the head descends. These accommodations, including the increase in intracranial pressure, are adaptive and necessary for efficient descent of the head while safeguarding cerebral blood flow. Autonomic reflexes mediated through central receptors normally provide ample protection of the brain from the considerable pressure exerted on the skull. On occasion, those forces, which are transmitted intracranially, may overcome the various adaptive anatomical, cardiovascular, metabolic, and neurological mechanisms that maintain cerebral perfusion and oxygen availability, resulting in ischemic brain injury. Accepting the notion of a potentially adverse impact of fetal head compression suggests that avoidance of excessive uterine activity and of relentless pushing without steady progress in descent may offer protection for the fetal brain during parturition. Excessive head compression should be considered in the differential diagnosis of ischemic encephalopathy.

Audit of Neonatal Jaundice as Experienced at a Mission Hospital in Western Nigeria

Introduction: Neonatal jaundice (NNJ) is a common disorder in neonates that can impact negatively on the brain and cause death. The peculiarities in aetiology and solutions for different settings are a knowledge gap. This informed the desire to determine local aetiology and solutions for neonatal jaundice in a missionary hospital in Abeokuta, Southwestern Nigeria. Methods: Consecutive consenting babies diagnosed with significant neonatal jaundice were studied between July 2016 and June 2019. Institutional ethical consent was obtained. A proforma was used to obtain socio-demographic data and other relevant information such as age, sex, birthweight, gestational age and history regarding the jaundice. All the information obtained was inputted into a computer and analysed with SPSS version 16. Results: A total of 179 babies with neonatal jaundice comprising of 120 (67.0%) boys and 59 (33.0%) girls with ages ranging between 1 and 12 days (mean 2.7 ± 2.9) were studied. Prematurity, ABO incompatibility, neonatal sepsis and glucose-6-phosphate enzyme deficiency accounted for over 80% of the causes of significant NNJ. Sixty (33.5%) of the 179 babies studied developed acute bilirubin encephalopathy and 11 (6.1%) mortalities were recorded. Higher proportions of babies that were out-born with spontaneous vaginal delivery modes had acute bilirubin encephalopathy (p < 0.05). Mothers with formal education had better outcome compared to mothers without, in terms of mortalities (p < 0.05). Conclusion: Neonatal jaundice is still a significant cause of morbidity and mortality in the neonatal age group. Maternal education is key to good outcome in neonatal jaundice.

Tacrolimus-induced posterior reversible encephalopathy syndrome following liver transplantation

In this editorial,we talk about a compelling case focusing on posterior reversible encephalopathy syndrome(PRES)as a complication in patients undergoing liver transplantation and treated with Tacrolimus.Tacrolimus(FK 506),derived from Streptomyces tsukubaensis,is a potent immunosuppressive macrolide.It inhibits Tcell transcription by binding to FK-binding protein,and is able to amplify glucocorticoid and progesterone effects.Tacrolimus effectively prevents allograft rejection in transplant patients but has adverse effects such as Tacrolimus-related PRES.PRES presents with various neurological symptoms alongside elevated blood pressure,and is primarily characterized by vasogenic edema on neuroimaging.While computed tomography detects initial lesions,magnetic resonance imaging,especially the Fluid-Attenuated Inversion Recovery sequence,is superior for diagnosing cortical and subcortical edema.Our discussion centers on the incidence of PRES in solid organ transplant recipients,which ranges between 0.5 to 5+ACU-,with varying presentations,from seizures to visual disturbances.The case of a 66-year-old male status post liver transplantation highlights the diagnostic and management challenges associated with Tacrolimus-related PRES.Radiographically evident in the parietal and occipital lobes,PRES underlines the need for heightened vigilance among healthcare providers.This editorial emphasizes the importance of early recognition,accurate diagnosis,and effective management of PRES to optimize outcomes in liver transplant patients.The case further explores the balance between the efficacy of immunosuppression with Tacrolimus and its potential neurological risks,underlining the necessity for careful monitoring and intervention strategies in this patient population.

Progress in pathogenesis and treatment of type A hepatic encephalopathy in acute liver failure:a comprehensive review

Hepatic encephalopathy is a serious neuropsychiatric complication caused by liver failure,which is characterized by the development of cognitive and motor disorders into coma.Typically,hepatic encephalopathy can be divided into three types(A,B,and C)according to the etiology.Type A hepatic encephalopathy(AHE)caused by acute liver failure seriously affects the prognosis of patients,ranging from mild neuropsychological changes to coma,brain edema,and even death.So far,the research on the pathogenesis of AHE has focused on the toxic effects of ammonia on the central nervous system,metabolic disorders(glutamine and lactate accumulation),neurotransmission alteration,systemic inflammation,especially neuro-inflammation.All these mechanisms are not independent,but mutually have synergistic effects.In clinic,treatment of AHE based on only one mechanism is often ineffective.To clarify the pathogenesis and the interaction among the mechanisms will be beneficial to the effective treatment of AHE and reduce the mortality.The aim of this review is to provide comprehensive scientific evidence for the clinical treatment of AHE via collecting and analyzing the latest mechanism of AHE,and clarifying the relationship among these mechanisms combing the investigation of the latest research progress of drug treatment of acute liver failure.Consequently,we find that the pathogenesis of AHE is a complex neurocognitive disorder shaped by interactions among hyperammonemia,inflammation,and changes in neurotransmission,the signaling pathways thereby integrating the inflammatory and neurological inputs to impact pathophysiological or neurobehavioral outcomes.

Inducing prion protein shedding as a neuroprotective and regenerative approach in pathological conditions of the brain:from theory to facts

In the last decades,the role of the prion protein(PrP) in neurodegenerative diseases has been intensively investigated,initially in prion diseases of humans(e.g., Creutzfeldt-J akob disease) and animals(e.g.,scrapie in sheep,chronic wasting disease in deer and elk,or "mad cow disease" in cattle).Templated misfolding of physiological cellular prion protein(PrPC) into an aggregation-prone isoform(termed PrP "Scrapie"(PrPSc)),self-re plication and spreading of the latter inside the brain and to peripheral tissues,and the associated formation of infectious proteopathic seeds(termed "prions")are among the essential pathogenic mechanisms underlying this group of fatal and transmissible spongiform encephalopathies.Late r,key roles of the correctly folded PrPCwere identified in more common human brain diseases(such as Alzheimer s disease or Parkinson’s disease) associated with the misfolding and/or accumulation of other proteins(such as amyloid-β,tau or α-synuclein,respectively).PrPChas also been linked with n euro protective and regenerative functions,for instance in hypoxic/ischemic conditions such as stroke.However,despite a mixed "bouquet" of suggested functions,our understanding of pathological and,especially,physiological roles played by PrPCin the brain and beyond is ce rtainly incomplete.Interactions with various other proteins at the cell surfa ce or within intracellular compartments may account for the functional diversity linked with PrPC.Moreover,conserved endogenous proteolytic processing of PrPCgenerates seve ral defined PrPCfragments,possibly holding intrinsic functions in physiological and pathological conditions,thus making the "true and complete biology" of this protein more complicated to be elucidated.Here,we focus on one of those released PrPCfragments,namely shed PrP(sPrP),generated by a membrane-proximate ADAM10-mediated cleavage event at the cell surfa ce.Similar to other soluble PrP fragments(such as the N1 fragment representing PrP’s released N-terminal tail upon the major α-cleavage event)or expe rimentally employed recombinant PrP,sPrP is being suggested to act n euro protective in Alzheimer’s disease and other protein misfolding diseases.Seve ral lines of evidence on extracellular PrPC(fragments) suggest that induction of PrPCrelease co uld be a future therapeutic option in various brain disorders.Our recent identification of a substrate-specific approach to stimulate the shedding by ADAM 10,based on ligands binding to cell surface PrPC,may further set the stage for research into this direction.

Ion channels in neurodevelopment:lessons from the Integrin-KCNB1 channel complex

Ion channels modulate cellular excitability by regulating ionic fluxes across biological membranes.Pathogenic mutations in ion channel genes give rise to epileptic disorders that are among the most frequent neurological diseases affecting millions of individuals worldwide.Epilepsies are trigge red by an imbalance between excitatory and inhibitory conductances.However,pathogenic mutations in the same allele can give rise to loss-of-function and/or gain-of-function va riants,all able to trigger epilepsy.Furthermore,certain alleles are associated with brain malformations even in the absence of a clear electrical phenotype.This body of evidence argues that the underlying epileptogenic mechanisms of ion channels are more diverse than originally thought.Studies focusing on ion channels in prenatal cortical development have shed light on this apparent paradox.The picture that emerges is that ion channels play crucial roles in landmark neurodevelopmental processes,including neuronal migration,neurite outgrowth,and synapse formation.Thus,pathogenic channel mutants can not only cause epileptic disorders by alte ring excitability,but further,by inducing morphological and synaptic abnormalities that are initiated during neocortex formation and may persist into the adult brain.

Reperfusion after hypoxia-ischemia exacerbates brain injury with compensatory activation of the antiferroptosis system:based on a novel rat model

Hypoxic-ischemic encephalopathy,which predisposes to neonatal death and neurological sequelae,has a high morbidity,but there is still a lack of effective prevention and treatment in clinical practice.To better understand the pathophysiological mechanism underlying hypoxic-ischemic encephalopathy,in this study we compared hypoxic-ischemic reperfusion brain injury and simple hypoxic-ischemic brain injury in neonatal rats.First,based on the conventional RiceVannucci model of hypoxic-ischemic encephalopathy,we established a rat model of hypoxic-ischemic reperfusion brain injury by creating a common carotid artery muscle bridge.Then we performed tandem mass tag-based proteomic analysis to identify differentially expressed proteins between the hypoxic-ischemic reperfusion brain injury model and the conventional Rice-Vannucci model and found that the majority were mitochondrial proteins.We also performed transmission electron microscopy and found typical characteristics of ferroptosis,including mitochondrial shrinkage,ruptured mitochondrial membranes,and reduced or absent mitochondrial cristae.Further,both rat models showed high levels of glial fibrillary acidic protein and low levels of myelin basic protein,which are biological indicators of hypoxic-ischemic brain injury and indicate similar degrees of damage.Finally,we found that ferroptosis-related Ferritin(Fth1)and glutathione peroxidase 4 were expressed at higher levels in the brain tissue of rats with hypoxic-ischemic reperfusion brain injury than in rats with simple hypoxic-ischemic brain injury.Based on these results,it appears that the rat model of hypoxic-ischemic reperfusion brain injury is more closely related to the pathophysiology of clinical reperfusion.Reperfusion not only aggravates hypoxic-ischemic brain injury but also activates the anti-ferroptosis system.