Targeting TrkB–PSD-95 coupling to mitigate neurological disorders

Tropomyosin receptor kinase B(TrkB)signaling plays a pivotal role in dendritic growth and dendritic spine formation to promote learning and memory.The activity-dependent release of brain-derived neurotrophic factor at synapses binds to pre-or postsynaptic TrkB resulting in the strengthening of synapses,reflected by long-term potentiation.Postsynaptically,the association of postsynaptic density protein-95 with TrkB enhances phospholipase Cγ-Ca^(2+)/calmodulin-dependent protein kinaseⅡand phosphatidylinositol 3-kinase-mechanistic target of rapamycin signaling required for long-term potentiation.In this review,we discuss TrkB-postsynaptic density protein-95 coupling as a promising strategy to magnify brain-derived neurotrophic factor signaling towards the development of novel therapeutics for specific neurological disorders.A reduction of TrkB signaling has been observed in neurodegenerative disorders,such as Alzheimer's disease and Huntington's disease,and enhancement of postsynaptic density protein-95 association with TrkB signaling could mitigate the observed deficiency of neuronal connectivity in schizophrenia and depression.Treatment with brain-derived neurotrophic factor is problematic,due to poor pharmacokinetics,low brain penetration,and side effects resulting from activation of the p75 neurotrophin receptor or the truncated TrkB.T1 isoform.Although TrkB agonists and antibodies that activate TrkB are being intensively investigated,they cannot distinguish the multiple human TrkB splicing isoforms or cell type-specific functions.Targeting TrkB–postsynaptic density protein-95 coupling provides an alternative approach to specifically boost TrkB signaling at localized synaptic sites versus global stimulation that risks many adverse side effects.

Role of copper in central nervous system physiology and pathology

Copper is a transition metal and an essential element for the organism,as alterations in its homeostasis leading to metal accumulation or deficiency have pathological effects in several organs,including the central nervous system.Central copper dysregulations have been evidenced in two genetic disorders characterized by mutations in the copper-ATPases ATP7A and ATP7B,Menkes disease and Wilson’s disease,respectively,and also in multifactorial neurological disorders such as Alzheimer’s disease,Parkinson’s disease,amyotrophic lateral sclerosis,and multiple sclerosis.This review summarizes current knowledge about the role of copper in central nervous system physiology and pathology,reports about unbalances in copper levels and/or distribution under disease,describes relevant animal models for human disorders where copper metabolism genes are dysregulated,and discusses relevant therapeutic approaches modulating copper availability.Overall,alterations in copper metabolism may contribute to the etiology of central nervous system disorders and represent relevant therapeutic targets to restore tissue homeostasis.

Evidence supporting the relationship between maternal asthma and risk for autism spectrum disorders

During pregnancy,maternal immune activation(MIA),due to infection,chronic inflammatory disorders,or toxic exposures,can result in lasting health impacts on the developing fetus.MIA has been associated with an increased risk of neurodevelopmental disorders,such as autism spectrum disorder(ASD)in the offspring.ASD is characterized by increased repetitive and stereotyped behaviors and decreased sociability.As of 2020,1 in 36 children are diagnosed with ASD by the age of 8 years,with ASD rates continuing to increase in prevalence in USA(Tamayo et al.,2023).Post-mortem brain studies,biomarker and transcriptomic studies,and epidemiology studies have provided compelling evidence of immune dysregulation in the circulation and brain of individuals diagnosed with ASD.Currently,the etiology of ASD is largely unknown,however,genetic components and environmental factors can contribute to increased susceptibility.Maternal allergic asthma(MAA),a form of MIA,has been identified as a potential risk factor for developing neurodevelopmental disorders(Patel et al.,2020).Asthma is a chronic inflammatory condition driven by a T-helper type(TH)2 immune response.

Peripheral mitochondrial DNA as a neuroinflammatory biomarker for major depressive disorder

In the pathogenesis of major depressive disorder, chronic stress-related neuroinflammation hinders favorable prognosis and antidepressant response. Mitochondrial DNA may be an inflammatory trigger, after its release from stress-induced dysfunctional central nervous system mitochondria into peripheral circulation. This evidence supports the potential use of peripheral mitochondrial DNA as a neuroinflammatory biomarker for the diagnosis and treatment of major depressive disorder. Herein, we critically review the neuroinflammation theory in major depressive disorder, providing compelling evidence that mitochondrial DNA release acts as a critical biological substrate, and that it constitutes the neuroinflammatory disease pathway. After its release, mitochondrial DNA can be carried in the exosomes and transported to extracellular spaces in the central nervous system and peripheral circulation. Detectable exosomes render encaged mitochondrial DNA relatively stable. This mitochondrial DNA in peripheral circulation can thus be directly detected in clinical practice. These characteristics illustrate the potential for mitochondrial DNA to serve as an innovative clinical biomarker and molecular treatment target for major depressive disorder. This review also highlights the future potential value of clinical applications combining mitochondrial DNA with a panel of other biomarkers, to improve diagnostic precision in major depressive disorder.

Potassium and calcium channels in different nerve cells act as therapeutic targets in neurological disorders

The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems.

Aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders:progress of experimental models based on disease pathogenesis

Neuromyelitis optica spectrum disorders are neuroinflammatory demyelinating disorders that lead to permanent visual loss and motor dysfunction.To date,no effective treatment exists as the exact causative mechanism remains unknown.Therefore,experimental models of neuromyelitis optica spectrum disorders are essential for exploring its pathogenesis and in screening for therapeutic targets.Since most patients with neuromyelitis optica spectrum disorders are seropositive for IgG autoantibodies against aquaporin-4,which is highly expressed on the membrane of astrocyte endfeet,most current experimental models are based on aquaporin-4-IgG that initially targets astrocytes.These experimental models have successfully simulated many pathological features of neuromyelitis optica spectrum disorders,such as aquaporin-4 loss,astrocytopathy,granulocyte and macrophage infiltration,complement activation,demyelination,and neuronal loss;however,they do not fully capture the pathological process of human neuromyelitis optica spectrum disorders.In this review,we summarize the currently known pathogenic mechanisms and the development of associated experimental models in vitro,ex vivo,and in vivo for neuromyelitis optica spectrum disorders,suggest potential pathogenic mechanisms for further investigation,and provide guidance on experimental model choices.In addition,this review summarizes the latest information on pathologies and therapies for neuromyelitis optica spectrum disorders based on experimental models of aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders,offering further therapeutic targets and a theoretical basis for clinical trials.

Potential role and therapeutic implications of glutathione peroxidase 4 in the treatment of Alzheimer's disease

Alzheimer's disease is an age-related neurodegenerative disorder with a complex and incompletely understood pathogenesis. Despite extensive research, a cure for Alzheimer's disease has not yet been found. Oxidative stress mediates excessive oxidative responses, and its involvement in Alzheimer's disease pathogenesis as a primary or secondary pathological event is widely accepted. As a member of the selenium-containing antioxidant enzyme family, glutathione peroxidase 4 reduces esterified phospholipid hydroperoxides to maintain cellular redox homeostasis. With the discovery of ferroptosis, the central role of glutathione peroxidase 4 in anti-lipid peroxidation in several diseases, including Alzheimer's disease, has received widespread attention. Increasing evidence suggests that glutathione peroxidase 4 expression is inhibited in the Alzheimer's disease brain, resulting in oxidative stress, inflammation, ferroptosis, and apoptosis, which are closely associated with pathological damage in Alzheimer's disease. Several therapeutic approaches, such as small molecule drugs, natural plant products, and non-pharmacological treatments, ameliorate pathological damage and cognitive function in Alzheimer's disease by promoting glutathione peroxidase 4 expression and enhancing glutathione peroxidase 4 activity. Therefore, glutathione peroxidase 4 upregulation may be a promising strategy for the treatment of Alzheimer's disease. This review provides an overview of the gene structure, biological functions, and regulatory mechanisms of glutathione peroxidase 4, a discussion on the important role of glutathione peroxidase 4 in pathological events closely related to Alzheimer's disease, and a summary of the advances in small-molecule drugs, natural plant products, and non-pharmacological therapies targeting glutathione peroxidase 4 for the treatment of Alzheimer's disease. Most prior studies on this subject used animal models, and relevant clinical studies are lacking. Future clinical trials are required to validate the therapeutic effects of strategies targeting glutathione peroxidase 4 in the treatment of Alzheimer's disease.

Exploiting fly models to investigate rare human neurological disorders

Rare neurological diseases,while individually are rare,collectively impact millions globally,leading to diverse and often severe neurological symptoms.Often attributed to genetic mutations that disrupt protein function or structure,understanding their genetic basis is crucial for accurate diagnosis and targeted therapies.To investigate the underlying pathogenesis of these conditions,researchers often use non-mammalian model organisms,such as Drosophila(fruit flies),which is valued for their genetic manipulability,cost-efficiency,and preservation of genes and biological functions across evolutionary time.Genetic tools available in Drosophila,including CRISPR-Cas9,offer a means to manipulate gene expression,allowing for a deep exploration of the genetic underpinnings of rare neurological diseases.Drosophila boasts a versatile genetic toolkit,rapid generation turnover,and ease of large-scale experimentation,making it an invaluable resource for identifying potential drug candidates.Researchers can expose flies carrying disease-associated mutations to various compounds,rapidly pinpointing promising therapeutic agents for further investigation in mammalian models and,ultimately,clinical trials.In this comprehensive review,we explore rare neurological diseases where fly research has significantly contributed to our understanding of their genetic basis,pathophysiology,and potential therapeutic implications.We discuss rare diseases associated with both neuron-expressed and glial-expressed genes.Specific cases include mutations in CDK19 resulting in epilepsy and developmental delay,mutations in TIAM1 leading to a neurodevelopmental disorder with seizures and language delay,and mutations in IRF2BPL causing seizures,a neurodevelopmental disorder with regression,loss of speech,and abnormal movements.And we explore mutations in EMC1 related to cerebellar atrophy,visual impairment,psychomotor retardation,and gain-of-function mutations in ACOX1 causing Mitchell syndrome.Loss-of-function mutations in ACOX1 result in ACOX1 deficiency,characterized by very-long-chain fatty acid accumulation and glial degeneration.Notably,this review highlights how modeling these diseases in Drosophila has provided valuable insights into their pathophysiology,offering a platform for the rapid identification of potential therapeutic interventions.Rare neurological diseases involve a wide range of expression systems,and sometimes common phenotypes can be found among different genes that cause abnormalities in neurons or glia.Furthermore,mutations within the same gene may result in varying functional outcomes,such as complete loss of function,partial loss of function,or gain-of-function mutations.The phenotypes observed in patients can differ significantly,underscoring the complexity of these conditions.In conclusion,Drosophila represents an indispensable and cost-effective tool for investigating rare neurological diseases.By facilitating the modeling of these conditions,Drosophila contributes to a deeper understanding of their genetic basis,pathophysiology,and potential therapies.This approach accelerates the discovery of promising drug candidates,ultimately benefiting patients affected by these complex and understudied diseases.

Lipid droplets in the nervous system:involvement in cell metabolic homeostasis

Lipid droplets serve as primary storage organelles for neutral lipids in neurons,glial cells,and other cells in the nervous system.Lipid droplet formation begins with the synthesis of neutral lipids in the endoplasmic reticulum.Previously,lipid droplets were recognized for their role in maintaining lipid metabolism and energy homeostasis;however,recent research has shown that lipid droplets are highly adaptive organelles with diverse functions in the nervous system.In addition to their role in regulating cell metabolism,lipid droplets play a protective role in various cellular stress responses.Furthermore,lipid droplets exhibit specific functions in neurons and glial cells.Dysregulation of lipid droplet formation leads to cellular dysfunction,metabolic abnormalities,and nervous system diseases.This review aims to provide an overview of the role of lipid droplets in the nervous system,covering topics such as biogenesis,cellular specificity,and functions.Additionally,it will explore the association between lipid droplets and neurodegenerative disorders.Understanding the involvement of lipid droplets in cell metabolic homeostasis related to the nervous system is crucial to determine the underlying causes and in exploring potential therapeutic approaches for these diseases.

Glucocorticoid receptor signaling in the brain and its involvement in cognitive function

The hypothalamic-pituitary-adrenal axis regulates the secretion of glucoco rticoids in response to environmental challenges.In the brain,a nuclear receptor transcription fa ctor,the glucocorticoid recepto r,is an important component of the hypothalamicpituitary-a d renal axis's negative feedback loop and plays a key role in regulating cognitive equilibrium and neuroplasticity.The glucoco rticoid receptor influences cognitive processes,including glutamate neurotransmission,calcium signaling,and the activation of brain-derived neurotrophic factor-mediated pathways,through a combination of genomic and non-genomic mechanisms.Protein interactions within the central nervous system can alter the expression and activity of the glucocorticoid receptor,there by affecting the hypothalamic-pituitary-a d renal axis and stress-related cognitive functions.An appropriate level of glucocorticoid receptor expression can improve cognitive function,while excessive glucocorticoid receptors or long-term exposure to glucoco rticoids may lead to cognitive impairment.Patients with cognitive impairment-associated diseases,such as Alzheimer's disease,aging,depression,Parkinson's disease,Huntington's disease,stroke,and addiction,often present with dysregulation of the hypothalamic-pituitary-adrenal axis and glucocorticoid receptor expression.This review provides a comprehensive overview of the functions of the glucoco rticoid receptor in the hypothalamic-pituitary-a d renal axis and cognitive activities.It emphasizes that appropriate glucocorticoid receptor signaling fa cilitates learning and memory,while its dysregulation can lead to cognitive impairment.This provides clues about how glucocorticoid receptor signaling can be targeted to ove rcome cognitive disability-related disorders.

CNKSR2 interactome analysis indicates its association with the centrosome/microtubule system

The protein connector enhancer of kinase suppressor of Ras 2(CNKSR2),present in both the postsynaptic density and cytoplasm of neurons,is a scaffolding protein with several protein-binding domains.Variants of the CNKSR2 gene have been implicated in neurodevelopmental disorders,particularly intellectual disability,although the precise mechanism involved has not yet been fully understood.Research has demonstrated that CNKSR2 plays a role in facilitating the localization of postsynaptic density protein complexes to the membrane,thereby influencing synaptic signaling and the morphogenesis of dendritic spines.However,the function of CNKSR2 in the cytoplasm remains to be elucidated.In this study,we used immunoprecipitation and high-resolution liquid chromatography-mass spectrometry to identify the interactors of CNKSR2.Through a combination of bioinformatic analysis and cytological experiments,we found that the CNKSR2 interactors were significantly enriched in the proteome of the centrosome.We also showed that CNKSR2 interacted with the microtubule protein DYNC1H1 and with the centrosome marker CEP290.Subsequent colocalization analysis confirmed the centrosomal localization of CNKSR2.When we downregulated CNKSR2 expression in mouse neuroblastoma cells(Neuro 2A),we observed significant changes in the expression of numerous centrosomal genes.This manipulation also affected centrosome-related functions,including cell size and shape,cell proliferation,and motility.Furthermore,we found that CNKSR2 interactors were highly enriched in de novo variants associated with intellectual disability and autism spectrum disorder.Our findings establish a connection between CNKSR2 and the centrosome,and offer new insights into the underlying mechanisms of neurodevelopmental disorders.

Exploring the interaction between the gut microbiota and cyclic adenosine monophosphate-protein kinase A signaling pathway:a potential therapeutic approach for neurodegenerative diseases

The interaction between the gut microbiota and cyclic adenosine monophosphate(cAMP)-protein kinase A(PKA)signaling pathway in the host's central nervous system plays a crucial role in neurological diseases and enhances communication along the gut–brain axis.The gut microbiota influences the cAMP-PKA signaling pathway through its metabolites,which activates the vagus nerve and modulates the immune and neuroendocrine systems.Conversely,alterations in the cAMP-PKA signaling pathway can affect the composition of the gut microbiota,creating a dynamic network of microbial-host interactions.This reciprocal regulation affects neurodevelopment,neurotransmitter control,and behavioral traits,thus playing a role in the modulation of neurological diseases.The coordinated activity of the gut microbiota and the cAMP-PKA signaling pathway regulates processes such as amyloid-β protein aggregation,mitochondrial dysfunction,abnormal energy metabolism,microglial activation,oxidative stress,and neurotransmitter release,which collectively influence the onset and progression of neurological diseases.This study explores the complex interplay between the gut microbiota and cAMP-PKA signaling pathway,along with its implications for potential therapeutic interventions in neurological diseases.Recent pharmacological research has shown that restoring the balance between gut flora and cAMP-PKA signaling pathway may improve outcomes in neurodegenerative diseases and emotional disorders.This can be achieved through various methods such as dietary modifications,probiotic supplements,Chinese herbal extracts,combinations of Chinese herbs,and innovative dosage forms.These findings suggest that regulating the gut microbiota and cAMP-PKA signaling pathway may provide valuable evidence for developing novel therapeutic approaches for neurodegenerative diseases.

Biomarker bust:meta-analyses reveal unreliability of neuronal extracellular vesicles for diagnosing parkinsonian disorders

A range of neurodegenerative disorders,collectively termed parkinsonian disorders,present with a complex array of both motor and non-motor symptoms.Included in this group are Parkinson’s disease(PD),dementia with Lewy bodies(DLB),multiple system atrophy(MSA),corticobasal syndrome(CBS),and progressive supranuclear palsy(PSP).These disorders are differentiated neuropathologically by their dominant protein pathologies involvingα-synuclein(α-syn)and/or tau,the types of brain cells affected,such as neurons,oligodendroglia,and astrocytes,and the specific brain regions involved(Tolosa et al.,2021).

MicroRNAs as potential biomarkers for diagnosis of post-traumatic stress disorder

Post-traumatic stress disorder is a mental disorder caused by exposure to severe traumatic life events.Currently,there are no validated biomarkers or laboratory tests that can distinguish between trauma survivors with and without post-traumatic stress disorder.In addition,the heterogeneity of clinical presentations of post-traumatic stress disorder and the overlap of symptoms with other conditions can lead to misdiagnosis and inappropriate treatment.Evidence suggests that this condition is a multisystem disorder that affects many biological systems,raising the possibility that peripheral markers of disease may be used to diagnose post-traumatic stress disorder.We performed a PubMed search for microRNAs(miRNAs)in post-traumatic stress disorder(PTSD)that could serve as diagnostic biomarkers and found 18 original research articles on studies performed with human patients and published January 2012 to December 2023.These included four studies with whole blood,seven with peripheral blood mononuclear cells,four with plasma extracellular vesicles/exosomes,and one with serum exosomes.One of these studies had also used whole plasma.Two studies were excluded as they did not involve microRNA biomarkers.Most of the studies had collected samples from adult male Veterans who had returned from deployment and been exposed to combat,and only two were from recently traumatized adult subjects.In measuring miRNA expression levels,many of the studies had used microarray miRNA analysis,miRNA Seq analysis,or NanoString panels.Only six studies had used real time polymerase chain reaction assay to determine/validate miRNA expression in PTSD subjects compared to controls.The miRNAs that were found/validated in these studies may be considered as potential candidate biomarkers for PTSD and include miR-3130-5p in whole blood;miR-193a-5p,-7113-5p,-125a,-181c,and-671-5p in peripheral blood mononuclear cells;miR-10b-5p,-203a-3p,-4488,-502-3p,-874-3p,-5100,and-7641 in plasma extracellular vesicles/exosomes;and miR-18a-3p and-7-1-5p in blood plasma.Several important limitations identified in the studies need to be taken into account in future studies.Further studies are warranted with war veterans and recently traumatized children,adolescents,and adults having PTSD and use of animal models subjected to various stressors and the effects of suppressing or overexpressing specific microRNAs.

Advancement in utilization of magnetic resonance imaging and biomarkers in the understanding of schizophrenia

Historically,psychiatric diagnoses have been made based on patient’s reported symptoms applying the criteria from diagnostic and statistical manual of mental disorders.The utilization of neuroimaging or biomarkers to make the diagnosis and manage psychiatric disorders remains a distant goal.There have been several studies that examine brain imaging in psychiatric disorders,but more work is needed to elucidate the complexities of the human brain.In this editorial,we examine two articles by Xu et al and Stoyanov et al,that show developments in the direction of using neuroimaging to examine the brains of people with schizo-phrenia and depression.Xu et al used magnetic resonance imaging to examine the brain structure of patients with schizophrenia,in addition to examining neurotransmitter levels as biomarkers.Stoyanov et al used functional magnetic resonance imaging to look at modulation of different neural circuits by diagnostic-specific scales in patients with schizophrenia and depression.These two studies provide crucial evidence in advancing our understanding of the brain in prevalent psychiatric disorders.

Liposomes as versatile agents for the management of traumatic and nontraumatic central nervous system disorders:drug stability,targeting efficiency,and safety

Various nanoparticle-based drug delivery systems for the treatment of neurological disorders have been widely studied.However,their inability to cross the blood–brain barrier hampers the clinical translation of these therapeutic strategies.Liposomes are nanoparticles composed of lipid bilayers,which can effectively encapsulate drugs and improve drug delivery across the blood–brain barrier and into brain tissue through their targeting and permeability.Therefore,they can potentially treat traumatic and nontraumatic central nervous system diseases.In this review,we outlined the common properties and preparation methods of liposomes,including thin-film hydration,reverse-phase evaporation,solvent injection techniques,detergent removal methods,and microfluidics techniques.Afterwards,we comprehensively discussed the current applications of liposomes in central nervous system diseases,such as Alzheimer's disease,Parkinson's disease,Huntington's disease,amyotrophic lateral sclerosis,traumatic brain injury,spinal cord injury,and brain tumors.Most studies related to liposomes are still in the laboratory stage and have not yet entered clinical trials.Additionally,their application as drug delivery systems in clinical practice faces challenges such as drug stability,targeting efficiency,and safety.Therefore,we proposed development strategies related to liposomes to further promote their development in neurological disease research.

Magnetic resonance imaging evaluation and nuclear receptor binding SET domain protein 1 mutation in the Sotos syndrome with attention-deficit/hyperactivity disorder

Sotos syndrome is characterized by overgrowth features and is caused by alterations in the nuclear receptor binding SET domain protein 1 gene.Attentiondeficit/hyperactivity disorder(ADHD)is considered a neurodevelopment and psychiatric disorder in childhood.Genetic characteristics and clinical presentation could play an important role in the diagnosis of Sotos syndrome and ADHD.Magnetic resonance imaging(MRI)has been used to assess medical images in Sotos syndrome and ADHD.The images process is considered to display in MRI while wavelet fusion has been used to integrate distinct images for achieving more complete information in single image in this editorial.In the future,genetic mechanisms and artificial intelligence related to medical images could be used in the clinical diagnosis of Sotos syndrome and ADHD.

Autism spectrum disorder:difficulties in diagnosis and microRNA biomarkers

We performed a PubMed search for microRNAs in autism spectrum disorder that could serve as diagnostic biomarkers in patients and selected 17 articles published from January 2008 to December 2023,of which 4 studies were performed with whole blood,4 with blood plasma,5 with blood serum,1 with serum neural cell adhesion molecule L1-captured extracellular vesicles,1 with blood cells,and 2 with peripheral blood mononuclear cells.Most of the studies involved children and the study cohorts were largely males.Many of the studies had performed microRNA sequencing or quantitative polymerase chain reaction assays to measure microRNA expression.Only five studies had used real-time polymerase chain reaction assay to validate microRNA expression in autism spectrum disorder subjects compared to controls.The microRNAs that were validated in these studies may be considered as potential candidate biomarkers for autism spectrum disorder and include miR-500a-5p,-197-5p,-424-5p,-664a-3p,-365a-3p,-619-5p,-664a-3p,-3135a,-328-3p,and-500a-5p in blood plasma and miR-151a-3p,-181b-5p,-320a,-328,-433,-489,-572,-663a,-101-3p,-106b-5p,-19b-3p,-195-5p,and-130a-3p in blood serum of children,and miR-15b-5p and-6126 in whole blood of adults.Several important limitations were identified in the studies reviewed,and need to be taken into account in future studies.Further studies are warranted with children and adults having different levels of autism spectrum disorder severity and consideration should be given to using animal models of autism spectrum disorder to investigate the effects of suppressing or overexpressing specific microRNAs as a novel therapy.

MicroRNAs as potential diagnostic biomarkers for bipolar disorder

Abnormal expression of microRNAs is connected to brain development and disease and could provide novel biomarkers for the diagnosis and prognosis of bipolar disorder. We performed a PubMed search for microRNA biomarkers in bipolar disorder and found 18 original research articles on studies performed with human patients and published from January 2011 to June 2023. These studies included microRNA profiling in bloodand brain-based materials. From the studies that had validated the preliminary findings,potential candidate biomarkers for bipolar disorder in adults could be miR-140-3p,-30d-5p,-330-5p,-378a-5p,-21-3p,-330-3p,-345-5p in whole blood, miR-19b-3p,-1180-3p,-125a-5p, let-7e-5p in blood plasma, and miR-7-5p,-23b-5p,-142-3p,-221-5p,-370-3p in the blood serum. Two of the studies had investigated the changes in microRNA expression of patients with bipolar disorder receiving treatment. One showed a significant increase in plasma miR-134 compared to baseline after 4 weeks of treatment which included typical antipsychotics, atypical antipsychotics, and benzodiazepines. The other study had assessed the effects of prescribed medications which included neurotransmitter receptorsite binders(drug class B) and sedatives, hypnotics, anticonvulsants, and analgesics(drug class C) on microRNA results. The combined effects of the two drug classes increased the significance of the results for miR-219 and-29c with miR-30e-3p and-526b* acquiring significance. MicroRNAs were tested to see if they could serve as biomarkers of bipolar disorder at different clinical states of mania, depression, and euthymia. One study showed that upregulation in whole blood of miR-9-5p,-29a-3p,-106a-5p,-106b-5p,-107,-125a-3p,-125b-5p and of miR-107,-125a-3p occurred in manic and euthymic patients compared to controls, respectively, and that upregulation of miR-106a-5p,-107 was found for manic compared to euthymic patients. In two other studies using blood plasma,downregulation of miR-134 was observed in manic patients compared to controls, and dysregulation of miR-134,-152,-607,-633,-652,-155 occurred in euthymic patients compared to controls. Finally, microRNAs such as miR-34a,-34b,-34c,-137, and-140-3p,-21-3p,-30d-5p,-330-5p,-378a-5p,-134,-19b-3p were shown to have diagnostic potential in distinguishing bipolar disorder patients from schizophrenia or major depressive disorder patients, respectively. Further studies are warranted with adolescents and young adults having bipolar disorder and consideration should be given to using animal models of the disorder to investigate the effects of suppressing or overexpressing specific microRNAs.

Macular microvascular and structural changes on optical coherence tomography angiography in atypical optic neuritis

BACKGROUND Atypical optic neuritis,consisting of neuromyelitis optica spectrum disorders(NMOSD)or myelin oligodendrocyte glycoprotein antibody disease(MOGAD),has a very similar presentation but different prognostic implications and longterm management strategies.Vascular and metabolic factors are being thought to play a role in such autoimmune neuro-inflammatory disorders,apart from the obvious immune mediated damage.With the advent of optical coherence tomography angiography(OCTA),it is easy to pick up on these subclinical macular microvascular and structural changes.AIM To study the macular microvascular and structural changes on OCTA in atypical optic neuritis.METHODS This observational cross-sectional study involved 8 NMOSD and 17 MOGAD patients,diagnosed serologically,as well as 10 healthy controls.Macular vascular density(MVD)and ganglion cell+inner plexiform layer thickness(GCIPL)were studied using OCTA.RESULTS There was a significant reduction in MVD in NMOSD and MOGAD affected as well as unaffected eyes when compared with healthy controls.NMOSD and MOGAD affected eyes had significant GCIPL thinning compared with healthy controls.NMOSD unaffected eyes did not show significant GCIPL thinning compared to healthy controls in contrast to MOGAD unaffected eyes.On comparing NMOSD with MOGAD,there was no significant difference in terms of MVD or GCIPL in the affected or unaffected eyes.CONCLUSION Although significant microvascular and structural changes are present on OCTA between atypical optic neuritis and normal patients,they could not help in differentiating between NMOSD and MOGAD cases.