ST2 levels and neurodegenerative diseases: is this a significant relation?

Interleukin-33 (IL-33), belonging to the interleukin-1 cytokine family, has a decoy receptor soluble ST2 (sST2). IL-33 is found in oligodendrocytes and astrocytes and is involved in central nervous system healing and repair, whereas ST2 is found in microglia and astrocytes. Some studies have found a link between changes in the IL-33/ST2 pathway and neurodegenerative disorders. This review article investigates the relationship between the interleukin-33 (IL-33)/ST2 pathway and neurodegenerative disorders. It was discovered that soluble st2 levels were increased. Furthermore, IL-33 levels were found to be lower in many neurodegenerative diseases such as Alzheimer's and amyotrophic lateral sclerosis (ALS). The association with other disorders, such as ankylosing spondylitis, multiple sclerosis, and systemic lupus erythematosus (SLE), was also observed. Various studies suggest that ST2/IL-33 signalling may be pivotal in the disease modulation of neurodegenerative disorders. The serum sST2 level test can be useful in determining the inflammatory status and severity of illness in many neurodegenerative disorders. In this review, we will discuss recent findings concerning the interleukin-33 (IL-33)/ST2 pathway and its role in the diagnosis and treatment of diseases with neurodegeneration.

Autophagy Deregulation in HIV-1-Infected Cells Increases Extracellular Vesicle Release and Contributes to TLR3 Activation

Human immunodeficiency virus type 1 (HIV-1) infection can result in HIV-associated neurocognitive disorder (HAND), a spectrum of disorders characterized by neurological impairment and chronic inflammation. Combined antiretroviral therapy (cART) has elicited a marked reduction in the number of individuals diagnosed with HAND. However, there is continual, low-level viral transcription due to the lack of a transcription inhibitor in cART regimens, which results in the accumulation of viral products within infected cells. To alleviate stress, infected cells can release accumulated products, such as TAR RNA, in extracellular vesicles (EVs), which can contribute to pathogenesis in neighboring cells. Here, we demonstrate that cART can contribute to autophagy deregulation in infected cells and increased EV release. The impact of EVs released from HIV-1 infected myeloid cells was found to contribute to CNS pathogenesis, potentially through EV-mediated TLR3 (Toll-like receptor 3) activation, suggesting the need for therapeutics to target this mechanism. Three HIV-1 TAR-binding compounds, 103FA, 111FA, and Ral HCl, were identified that recognize TAR RNA and reduce TLR activation. These data indicate that packaging of viral products into EVs, potentially exacerbated by antiretroviral therapeutics, may induce chronic inflammation of the CNS observed in cART-treated patients, and novel therapeutic strategies may be exploited to mitigate morbidity.

Localization of hyperpolarization-activated cyclic nucleotide-gated channels in the vertebrate retinas across species and their physiological roles

Transmembrane proteins known as hyperpolarization-activated cyclic nucleotide-gated (HCN) channels control the movement of Na+ and K+ ions across cellular membranes. HCN channels are known to be involved in crucial physiological functions in regulating neuronal excitability and rhythmicity, and pacemaker activity in the heart. Although HCN channels have been relatively well investigated in the brain, their distribution and function in the retina have received less attention, remaining their physiological roles to be comprehensively understood. Also, because recent studies reported HCN channels have been somewhat linked with the dysfunction of photoreceptors which are affected by retinal diseases, investigating HCN channels in the retina may offer valuable insights into disease mechanisms and potentially contribute to identifying novel therapeutic targets for retinal degenerative disorders. This paper endeavors to summarize the existing literature on the distribution and function of HCN channels reported in the vertebrate retinas of various species and discuss the potential implications for the treatment of retinal diseases. Then, we recapitulate current knowledge regarding the function and regulation of HCN channels, as well as their relevance to various neurological disorders.

Preclinical Evaluation of Azabenzimidazole-Based PET Radioligands for γ-8 Dependent Transmembrane AMPA Receptor Regulatory Protein Imaging

AMPA glutamate receptors (AMPARs) play a pivotal role in excitatory neurotransmission, particularly in the hippocampus where the TARP γ-8 subunit is enriched and serves as a target for emerging anti-epileptic drugs. To enable in vivo visualization of TARP γ-8 distribution and expression by positron emission tomography (PET), this study focuses on the development of novel 18 F-labeled TARP γ-8 inhibitors and their corresponding precursors, stemming from the azabenzimidazole scaffold. The resulting radioligands [18 F]TARP-2204 and [18 F]TARP-2205 were successfully synthesized with acceptable radiochemical yield, high molar activity, and excellent radiochemical purity. In vitro autoradiography demonstrates high level of specific binding of [18 F]TARP-2205 to TARP γ-8 in both rat and nonhuman primate brain tissues. However, unexpected radiodefluorination in PET imaging studies of rodents emphasizes the need for further structural refinement. This work serves as an excellent starting point for the development of future 18 F-labeled TARP γ-8 PET tracers, offering valuable insights into medicinal chemistry design, radiosynthesis and subsequent PET evaluation.

Brain-derived extracellular vesicles: Potential diagnostic biomarkers for central nervous system diseases

Extracellular vesicles (EVs) are membrane-enclosed nanovesicles secreted by cells into the extracellular space and contain functional biomolecules, e.g. signaling receptors, bioactive lipids, nucleic acids, and proteins, which can serve as biomarkers. Neurons and glial cells secrete EVs, contributing to various physiological and pathological aspects of brain diseases. EVs confer their role in the bidirectional crosstalk between the central nervous system (CNS) and the periphery owing to their distinctive ability to cross the unique blood-brain barrier (BBB). Thus, EVs in the blood, cerebrospinal fluid (CSF), and urine can be intriguing biomarkers, enabling the minimally invasive diagnosis of CNS diseases. Although there has been an enormous interest in evaluating EVs as promising biomarkers, the lack of ultra-sensitive approaches for isolating and detecting brain-derived EVs (BDEVs) has hindered the development of efficient biomarkers. This review presents the recent salient findings of exosomal biomarkers, focusing on brain disorders. We summarize highly sensitive sensors for EV detection and state-of-the-art methods for single EV detection. Finally, the prospect of developing advanced EV analysis approaches for the non-invasive diagnosis of brain diseases is presented.

Advances in Neuro-Oncological Imaging: An Update on Diagnostic Approach to Brain Tumors

This study delineates the pivotal role of imaging within the field of neurology, emphasizing its significance in the diagnosis, prognostication, and evaluation of treatment responses for central nervous system (CNS) tumors. A comprehensive understanding of both the capabilities and limitations inherent in emerging imaging technologies is imperative for delivering a heightened level of personalized care to individuals with neuro-oncological conditions. Ongoing research in neuro-oncological imaging endeavors to rectify some limitations of radiological modalities, aiming to augment accuracy and efficacy in the management of brain tumors. This review is dedicated to the comparison and critical examination of the latest advancements in diverse imaging modalities employed in neuro-oncology. The objective is to investigate their respective impacts on diagnosis, cancer staging, prognosis, and post-treatment monitoring. By providing a comprehensive analysis of these modalities, this review aims to contribute to the collective knowledge in the field, fostering an informed approach to neuro-oncological care. In conclusion, the outlook for neuro-oncological imaging appears promising, and sustained exploration in this domain is anticipated to yield further breakthroughs, ultimately enhancing outcomes for individuals grappling with CNS tumors.

Navigating the brain: the role of exosomal shuttles in precision therapeutics

Brain diseases have become one of the leading roots of mortality and disability worldwide, contributing a significant part of the disease burden on healthcare systems. The blood-brain barrier (BBB) is a primary physical and biological obstacle that allows only small molecules to pass through it. Its selective permeability is a significant challenge in delivering therapeutics into the brain for treating brain dysfunction. It is estimated that only 2% of the new central nervous system (CNS) therapeutic compounds can cross the BBB and achieve their therapeutic targets. Scientists are exploring various approaches to develop effective cargo delivery vehicles to promote better therapeutics targeting the brain with minimal off-target side effects. Despite different synthetic carriers, one of the natural brain cargo delivery systems, "exosomes," are now employed to transport drugs through the BBB. Exosomes are naturally occurring small extracellular vesicles (EVs) with unique advantages as a therapeutic delivery system for treating brain disorders. They have beneficial innate aspects of biocompatibility, higher stability, ability to cross BBB, low cytotoxicity, low immunogenicity, homing potential, targeted delivery, and reducing off-site target effects. In this review, we will discuss the limitations of synthetic carriers and the utilization of naturally occurring exosomes as brain-targeted cargo delivery vehicles and highlight the methods for modifying exosome surfaces and drug loading into exosomes. We will also enlist neurodegenerative disorders targeted with genetically modified exosomes for their treatment.

Simulating neuronal development: exploring potential mechanisms for central nervous system metastasis in acute lymphoblastic leukemia

Background

Acute lymphoblastic leukemia (ALL) is prone to metastasize to the central nervous system (CNS), which is an important cause of poor treatment outcomes and unfavorable prognosis. However, the pathogenesis of CNS metastasis of ALL cells has not been fully illuminated. Recent reports have shed some light on the correlation between neural mechanisms and ALL CNS metastasis. These progressions prompt us to study the relationship between ALL central nervous system metastasis and neuronal development, exploring potential biomarkers and therapeutic targets of CNS metastasis.

Materials and methods

ALL central nervous system metastasis- and neuronal development-related differentially expressed genes (DEGs) were identified by analyzing gene expression datasets GSE60926 and GSE13715. Target prediction and network analysis methods were applied to assess protein-protein interaction networks. Gene Ontology (GO) terms and pathway enrichment for DEGs were assessed. Co-expressed differentially expressed genes (co-DEGs) coupled with corresponding predicted microRNAs (miRNAs) were studied as well. Reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry were employed for the validation of key co-DEGs in primary ALL cells. Furthermore, ALL cells were treated with a vascular endothelial growth factor (VEGF) inhibitor to block neuronal development and assess changes in the co-DEGs.

Results

We identified 216, 208, and 204 DEGs in ALL CNS metastasis specimens and neuronal development samples (GSE60926 and GSE13715). CD2, CD3G, CD3D, and LCK may be implicated in ALL CNS metastasis. LAMB1, MATN3, IGFBP3, LGALS1, and NEUROD1 may be associated with neuronal development. Specifically, four co-DEGs (LGALS1, TMEM71, SHISA2, and S100A11) may link ALL central nervous system metastasis and neuronal development process. The miRNAs for each co-DEG could be potential biomarkers or therapeutic targets for ALL central nervous system metastasis, especially hsa-miR-22-3p, hsa-miR-548t-5p, and hsa-miR-6134. Additionally, four co-DEGs (LGALS1, TMEM71, SHISA2, and S100A11) were validated in CNS-infiltrated ALL cells. The VEGF inhibitor demonstrated a suppressive effect on mRNA and protein expression of key co-DEGs.

Conclusion

The bioinformatic survey and key gene validation suggest a possible correlation between ALL CNS metastasis and the neuronal development process. Simulating the neuronal development process might be a possible strategy for CNS metastasis in ALL. LGALS1, TMEM71, SHISA2, and S100A11 genes are promising and novel biomarkers and targets in ALL CNS metastasis.

Drug delivery for neurodegenerative diseases is a problem, but lipid nanocarriers could provide the answer

Neurodegenerative disorders encompass diseases that involve the degeneration of neurons, particularly those within the central nervous system. These are the most commonly observed disorders among the geriatric population. The treatment or management of this condition presents additional challenges due to therapeutics that may not be as effective as desired. The primary obstacle that often hinders the efficacy of therapy is the existence of a blood-brain barrier (BBB). The BBB serves as a vital safeguard for the brain, effectively obstructing the passage of drugs into the brain cells. Hence, the management of damaging neurodegenerative conditions such as Alzheimer's disease (AD), Parkinson's disease (PD), Cerebrovascular diseases (CVDs), Huntington's disease (HD), and Multiple sclerosis (MS) is currently the primary area of research interest. The innovative utilization of nanoparticles as drug carriers provides renewed optimism in addressing many complicated medical conditions. In this article, I have aimed to gather published information regarding various lipid nanoparticles that can efficiently transport medication to the brain to address neurodegenerative disorders. According to the published literature, liposomes, solid-lipid nanoparticles, nanostructured nanoparticles, microemulsions, and nanoemulsions are potential nanocarriers that can treat neurodegenerative disorders.

Orosomucoid-1 Arises as a Shared Altered Protein in Two Models of Multiple Sclerosis

Multiple sclerosis (MS) is a complex autoimmune and neurodegenerative disorder that affects the central nervous system (CNS). It is characterized by a heterogeneous disease course involving demyelination and inflammation. In this study, we utilized two distinct animal models, cuprizone (CPZ)-induced demyelination and experimental autoimmune encephalomyelitis (EAE), to replicate various aspects of the disease. We aimed to investigate the differential CNS responses by examining the proteomic profiles of EAE mice during the peak disease (15 days post-induction) and cuprizone-fed mice during the acute phase (38 days). Specifically, we focused on two different regions of the CNS: the dorsal cortex (Cx) and the entire spinal cord (SC). Our findings revealed varied glial, synaptic, dendritic, mitochondrial, and inflammatory responses within these regions for each model. Notably, we identified a single protein, Orosomucoid-1 (Orm1), also known as Alpha-1-acid glycoprotein 1 (AGP1), that consistently exhibited alterations in both models and regions. This study provides insights into the similarities and differences in the responses of these regions in two distinct demyelinating models.

Cerebrospinal fluid flushing as a means of neuroprotection

Central nervous system (CNS) injury or disease states are often difficult to treat due to the closed system of the dura mater/blood-brain barrier and the bony skull and vertebrae. The closed system results in at least partial containment of any pro-inflammatory molecules, pathogens, or toxic byproducts in the case of brain or spinal cord lesions, which can result in a destructive feedback loop. Cervical-approach access techniques (lateral C1-C2, suboccipital and lateral atlanto-occipital space punctures) are less-common methods of cerebrospinal fluid (CSF) sampling due to the relative ease and safety of lumbar spinal taps. However, with improved image-guidance, these cervical-level CSF access points are still useful when there are certain contraindications and difficulties when attempting to sample the CSF via the typical lumbar spinal approach. With the advent of microcatheters and minimally invasive techniques, combined with body fluid filtration technology, the question arises: could dual microcatheters be introduced for inflow and outflow of purified or artificial CSF to break the destructive feedback loop and thus diminish CNS damage?. We hypothesize that intrathecal spinal catheters could be placed in 2 positions (e.g., via a cervical route and the typical lumbar spinal route) to allow for both an input and output to more effectively filter or "flush" the CSF. This could have broad implications in the treatment of strokes, traumatic brain or spinal cord injury, infections, autoimmune diseases, and even malignancies within the CNS-in short, any disease with abnormalities detectable in the CSF.

The emerging role of exosomes in communication between the periphery and the central nervous system

Exosomes, membrane-enclosed vesicles, are secreted by all types of cells. Exosomes can transport various molecules, including proteins, lipids, functional mRNAs, and microRNAs, and can be circulated to various recipient cells, leading to the production of local paracrine or distal systemic effects. Numerous studies have proved that exosomes can pass through the blood-brain barrier, thus, enabling the transfer of peripheral substances into the central nervous system (CNS). Consequently, exosomes may be a vital factor in the exchange of information between the periphery and CNS. This review will discuss the structure, biogenesis, and functional characterization of exosomes and summarize the role of peripheral exosomes deriving from tissues like the lung, gut, skeletal muscle, and various stem cell types in communicating with the CNS and influencing the brain's function. Then, we further discuss the potential therapeutic effects of exosomes in brain diseases and the clinical opportunities and challenges. Gaining a clearer insight into the communication between the CNS and the external areas of the body will help us to ascertain the role of the peripheral elements in the maintenance of brain health and illness and will facilitate the design of minimally invasive techniques for diagnosing and treating brain diseases.

The black swan: a case of central nervous system graft-versus-host disease

OBJECTIVES

Graft-versus-host disease (GVHD) of central nervous system is an atypical and rare manifestation of chronic GVHD, presenting with a heterogeneous spectrum of signs and symptoms. Diagnosis of neurological manifestations of GVHD can be highly challenging and remain associated with dismal prognosis, significant morbidity, and reduced quality of life.

CASE PRESENTATION

In this report, we describe a 39-year-old woman developing neurological signs and symptoms 8 months after allogeneic HSCT magnetic resonance imaging showed multifocal hyperintense lesions involving the periventricular region and frontal subcortical white matter. There was no laboratory evidence of infective or malignant etiology, and the case was diagnosed as CNS-GVHD. The patient was treated with intravenous methylprednisolone pulse therapy and the clinical conditions gradually improved. After few months, patient symptoms progressed despite the addition of high-dose intravenous immunoglobulin, tacrolimus, and a new course of high dose steroids. To engage targeted therapy, the patient underwent brain biopsy that revealed a loss of myelin fibers, perivascular and diffuse infiltration of T cells, and macrophages associated with reactive gliosis, representing a demyelinating disease. We intensified treatment with cyclophosphamide and subsequently introduced ibrutinib as salvage strategy. Despite a magnetic resonance imaging showing great regression of the demyelinating lesions, patient's conditions deteriorated and she died 16 months after HSCT.

CONCLUSIONS

CNS-GVHD is a rare complication of HSCT that is difficult to diagnose. Based on our experience, brain biopsy may represent a useful diagnostic tool when the clinical features of neurological symptoms are ambiguous or in patients without evidence of preceding chronic GVHD.

Two Cases of Acute Focal Bacterial Nephritis With Central Nervous System Manifestations in Children and Literature Review

Acute focal bacterial nephritis (AFBN) is a kidney disease characterized by a localized bacterial infection that manifests as an inflammatory mass. Most children with AFBN have nonspecific symptoms including fever, vomiting, and abdominal discomfort, and some develop neurological symptoms such as meningeal irritation, unconsciousness, and seizures as their condition worsens. This was 2 cases of AFBN with central nervous system manifestations in children, and we analyzed its possible mechanisms of the clinical and radiographic features. We experience 2 very unusual cases of AFBN which were linked to central nervous system abnormalities. A 6-year-old boy with AFBN and clinically moderate ncephalitis/encephalopathy with a reversible splenial lesion (MERS) presented with neurological symptoms, including unconsciousness and convulsions. The second case involved an 8-year-old child with AFBN-associated acute encephalopathy who exhibited neurological symptoms, including unconsciousness. According to previous research, AFBN is linked to central nervous system impairment. As a result, when a clinician meets a patient with an inexplicable fever caused by a neurological condition, he should pay attention to this diagnosis of AFBN and follow it in the abdominal graph.

Amino-terminal proteolytic fragment of the axon growth inhibitor Nogo-A (Rtn4A) is upregulated by injury and promotes axon regeneration

After adult mammalian central nervous system injury, axon regeneration is extremely limited or absent, resulting in persistent neurological deficits. Axon regeneration failure is due in part to the presence of inhibitory proteins, including NogoA (Rtn4A), from which two inhibitory domains have been defined. When these inhibitory domains are deleted, but an amino-terminal domain is still expressed in a gene trap line, mice show axon regeneration and enhanced recovery from injury. In contrast, when there is no amino-terminal Nogo-A fragment in the setting of inhibitory domain deletion, then axon regeneration and recovery are indistinguishable from WT. These data indicated that an amino-terminal Nogo-A fragment derived from the gene trap might promote axon regeneration, but this had not been tested directly and production of this fragment without gene targeting was unclear. Here, we describe posttranslation production of an amino-terminal fragment of Nogo-A from the intact gene product. This fragment is created by proteolysis near amino acid G214-N215 and levels are enhanced by axotomy. Furthermore, this fragment promotes axon regeneration in vitro and acts cell autonomously in neurons, in contrast to the inhibitory extracellular action of other Nogo-A domains.Proteins interacting with the amino-terminal Nogo-A fragment by immunoprecipitation include HSPA8 (HSC70, HSP7C). Suppression of HSPA8 expression by shRNA decreases axon regeneration from cerebral cortical neurons and overexpression increases axon regeneration. Moreover, the amino-terminal Nogo-A fragment increases HSPA8 chaperone activity. These data provide an explanation for varied results in different gene-targeted Nogo-A mice, as well as revealing an axon regeneration promoting domain of Nogo-A.

Large granular lymphocyte lymphoma with leukemic phase and suspicion of leptomeningeal lymphomatosis in a cat - a case report

INTRODUCTION

In this case report we present a feline large granular lymphocyte (LGL) lymphoma, a rare morphologically distinct subtype of lymphoma, in a twelve-year-old female spayed domestic short hair cat, with high suspicion of leptomeningeal lymphomatosis due to magnetic resonance imaging findings and results of cerebral spinal fluid analyses. Diagnosis of LGL lymphoma was confirmed by means of blood cytology and polymerase chain reaction for antigen receptor rearrangements.

The Upper Nasal Space: Option for Systemic Drug Delivery, Mucosal Vaccines and "Nose-to-Brain"

Sino-nasal disease is appropriately treated with topical treatment, where the nasal mucosa acts as a barrier to systemic absorption. Non-invasive nasal delivery of drugs has produced some small molecule products with good bioavailability. With the recent COVID pandemic and the need for nasal mucosal immunity becoming more appreciated, more interest has become focused on the nasal cavity for vaccine delivery. In parallel, it has been recognized that drug delivery to different parts of the nose can have different results and for "nose-to-brain" delivery, deposition on the olfactory epithelium of the upper nasal space is desirable. Here the non-motile cilia and reduced mucociliary clearance lead to longer residence time that permits enhanced absorption, either into the systemic circulation or directly into the CNS. Many of the developments in nasal delivery have been to add bioadhesives and absorption/permeation enhancers, creating more complicated formulations and development pathways, but other projects have shown that the delivery device itself may allow more differential targeting of the upper nasal space without these additions and that could allow faster and more efficient programs to bring a wider range of drugs-and vaccines-to market.

Sequential therapy with crizotinib and a second-generation ALK inhibitor versus direct therapy of a second-generation ALK inhibitor in ALK-positive advanced lung cancer: a real-world study

Background

There are few real-world studies in which the efficacy of sequential crizotinib and second-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are compared with direct therapy of second-generation ALK TKI in ALK-positive advanced lung cancer.

Methods

Between May 2014 and October 2022, 211 patients from the Zhejiang Cancer Hospital who harbored ALK rearrangement were analyzed. Of these patients, 115 received crizotinib with sequential second-generation ALK TKIs, and 96 patients received a second-generation ALK TKI directly. The survival analysis of median progression-free survival (PFS), overall survival (OS), and central nervous system time to progression (CNS TTP) in the various groups were calculated using the Kaplan-Meier method and compared by the log-rank test.

Results

Of the 211 lung cancer patients with ALK rearrangement, there were no statistical differences in PFS (25.27 vs. 20.47 months, P=0.644) and OS (70.27 months vs. not reached, P=0.991) between the 115 patients in the sequential therapy group and the 96 patients in the direct second-generation group. In the patients with baseline brain metastases at study entry (n=54), the sequential therapy group had a significantly shorter median CNS TTP than the direct second-generation group (10.40 vs. 22.40 months, P=0.040). Multivariate analyses revealed that the prognostic factors for PFS included performance status (PS, P=0.047) and brain metastases (P=0.010). For OS, the prognostic factors included PS (P=0.047) and liver metastases (P=0.021).

Conclusions

There was no statistical difference in efficacy between first-generation sequential second-generation ALK TKIs and direct therapy of second-generation ALK TKI regimens. The CNS efficacy of the direct second-generation group was better than that of the sequential therapy group. The prognostic factors for PFS included PS and brain metastases, while the prognostic factors for OS, PS and liver metastases were included.

Remyelination and Ageing: Ethical Considerations of Using Surgically Joined Animals in Research

Remyelination is a key repair process that ensures neurons remain protected following injury. This process is mediated by remyelinating oligodendrocytes in vertebrates, however, similarly to other neurobiological processes, the rate and efficiency of remyelination decreases across age and under pathological conditions. This has largely been attributed to two main contributors: 1) decreased exogenous signals supporting remyelination; and 2) aging of precursor cells that no longer differentiate into remyelinating oligodendrocytes. Here we discuss a key paper by Ruckh et al. (2012) who presented novel evidence that exposure to soluble bloodstream factors of young mice significantly rescues remyelination in old mice following a demyelinating insult. In this paper, a parabiosis approach was used where young and old mice were surgically joined for three weeks before and then left as a pair throughout the experiment. Ruckh and colleagues also offer novel insight into the role played by immune system cells, specifically macrophages, in clearance of myelin debris, a further contributor to remyelination. This paper is a good tool to expose undergraduate neuroscience students to basic molecular processes underlying conduction and transmission, helping them link cellular and network components. It also offers a platform for introducing the practicalities of in vivo research and debating ethical controversies that arise in animal research.

Synthesis, In Silico and In Vitro Characterization of Novel N,N-Substituted Pyrazolopyrimidine Acetamide Derivatives for the 18KDa Translocator Protein (TSPO)

The translocator protein (TSPO) is an interesting biological target for molecular imaging and therapy because the overexpression of TSPO is associated with microglial activation caused by neuronal damage or neuroinflammation, and these activated microglia are involved in various central nervous system (CNS) diseases. The TSPO is a target for neuroprotective treatment, which is used with the aim of reducing microglial cell activation. The novel N,N-disubstituted pyrazolopyrimidine acetamides scaffold (GMA 7-17), which bears a fluorine atom and is directly linked to the phenyl moiety, was synthesized, and each of the novel ligands was characterized in vitro. All of the newly synthesized ligands displayed picomolar to nanomolar affinity for the TSPO. Particularly, an in vitro affinity study led to the discovery of 2-(5,7-diethyl-2-(4-fluorophenyl)pyrazolo [1,5-a]pyrimidin-3-yl)-N-ethyl-N-phenylacetamide GMA 15 (Ki = 60 pM), a novel TSPO ligand that exhibits a 61-fold enhancement in affinity compared to the reference standard DPA-714 (Ki = 3.66 nM). Molecular dynamic (MD) studies of the highest affinity binder, GMA 15, were carried out to check its time-dependent stability with the receptor compared to DPA-714 and PK11195. The hydrogen bond plot also indicated that GMA 15 formed higher hydrogen bonds compared to DPA-714 and PK11195. We anticipate that further optimization to enhance the potency in a cellular assay needs to be followed, but our strategy of identifying potential TSPO binding novel scaffolds may open up a new avenue to develop novel TSPO ligands suited for potential molecular imaging and a wide range of therapeutic applications.

Multidrug-Loaded Lipid Nanoemulsions for the Combinatorial Treatment of Cerebral Cavernous Malformation Disease

Cerebral cavernous malformation (CCM) or cavernoma is a major vascular disease of genetic origin, whose main phenotypes occur in the central nervous system, and is currently devoid of pharmacological therapeutic strategies. Cavernomas can remain asymptomatic during a lifetime or manifest with a wide range of symptoms, including recurrent headaches, seizures, strokes, and intracerebral hemorrhages. Loss-of-function mutations in KRIT1/CCM1 are responsible for more than 50% of all familial cases, and have been clearly shown to affect cellular junctions, redox homeostasis, inflammatory responses, and angiogenesis. In this study, we investigated the therapeutic effects of multidrug-loaded lipid nanoemulsions in rescuing the pathological phenotype of CCM disease. The pro-autophagic rapamycin, antioxidant avenanthramide, and antiangiogenic bevacizumab were loaded into nanoemulsions, with the aim of reducing the major molecular dysfunctions associated with cavernomas. Through Western blot analysis of biomarkers in an in vitro CCM model, we demonstrated that drug-loaded lipid nanoemulsions rescue antioxidant responses, reactivate autophagy, and reduce the effect of pro-angiogenic factors better than the free drugs. Our results show the importance of developing a combinatorial preventive and therapeutic approach to reduce the risk of lesion formation and inhibit or completely revert the multiple hallmarks that characterize the pathogenesis and progression of cavernomas.

Aquaporin-4 Expression Switches from White to Gray Matter Regions during Postnatal Development of the Central Nervous System

Aquaporin-4 (AQP4) is the most abundant water channel in the central nervous system and plays a fundamental role in maintaining water homeostasis there. In adult mice, AQP4 is located mainly in ependymal cells, in the endfeet of perivascular astrocytes, and in the glia limitans. Meanwhile, its expression, location, and function throughout postnatal development remain largely unknown. Here, the expression of AQP4 mRNA was studied by in situ hybridization and RT-qPCR, and the localization and amount of protein was studied by immunofluorescence and western blotting, both in the brain and spinal cord. For this, wild-type mice of the C57BL/6 line, aged 1, 3, 7, 11, 20, and 60 days, and 18 months were used. The results showed a change in both the expression and location of AQP4 in postnatal development compared to those during adult life. In the early stages of postnatal development it appears in highly myelinated areas, such as the corpus callosum or cerebellum, and as the animal grows, it disappears from these areas, passing through the cortical regions of the forebrain and concentrating around the blood vessels. These findings suggest an unprecedented possible role for AQP4 in the early cell differentiation process, during the first days of life in the newborn animal, which will lead to myelination.

Glial cells: an important switch for the vascular function of the central nervous system

In this review, we first describe the current understanding of glial-mediated vascular function affecting the role of the blood-brain barrier (BBB) in central nervous system (CNS) disorders. BBB, mainly composed of glial and endothelial cells (ECs), is the protective structure that orchestrates the transport of substances, including ions, molecules, and cells from brain vessels into or out of the CNS. Then, we display the multiple communication between glial and vascular function based on angiogenesis, vascular wrapping, and blood perfusion in the brain. Glial can support microvascular ECs to form a blood network connecting to neurons. Astrocytes, microglia, and oligodendrocytes are the common types of glial surrounding the brain vessel. Glial-vessel interaction is required for the permeability and integrity of BBB. Glial cells surrounding the cerebral blood vessels can transmit communication signals to ECs and regulate the activity of vascular endothelial growth factor (VEGF) or Wnt-dependent endothelial angiogenesis mechanism. In addition, these glial cells monitor the blood flow in the brain via Ca²⁺/K⁺-dependent pathways. Finally, we provide a potential research direction for the glial-vessel axis in CNS disorders. Microglial activation can trigger astrocyte activation, which suggests that microglia-astrocyte interaction may play a key role in monitoring cerebral blood flow. Thus, microglia-astrocyte interaction can be the key point of follow-up studies focusing on the microglia-blood mechanism. More investigations focus on the mechanism of how oligodendrocyte progenitor cells communicate and interact with ECs. The direct role of oligodendrocytes in modulating vascular function needs to be explored in the future.

Modifying antibody-FcRn interactions to increase the transport of antibodies through the blood-brain barrier

The blood-brain barrier (BBB) largely excludes antibodies from entering the central nervous system, thus limiting the potential of therapeutic antibodies to treat conditions such as neurodegenerative diseases and neuro-psychiatric disorders. Here, we demonstrate that the transport of human antibodies across the BBB in mice can be enhanced by modulating their interactions with the neonatal Fc receptor (FcRn). When M252Y/S254T/T246E substitutions are introduced on the antibody Fc domain, immunohistochemical assays reveal widespread distribution of the engineered antibodies throughout the mouse brain. These engineered antibodies remain specific for their antigens and retain pharmacological activity. We propose that novel brain-targeted therapeutic antibodies can be engineered to differentially engage FcRn for receptor-mediated transcytosis across the BBB in order to improve neurological disease therapeutics in the future.

Enterovirus-71 utilizes small extracellular vesicles to cross the blood-brain barrier for infecting the central nervous system via transcytosis

BACKGROUND

Central nervous system (CNS) infections caused by Enterovirus 71 (EV71) pose a serious threat to children, causing severe neurogenic complications and even fatality in some patients. However, the pathogenesis of EV71 infections in the CNS remains unclear.

METHODS

An in vitro blood-brain barrier (BBB) model was constructed by coculturing brain microvascular endothelial cells (BMECs) and astrocytes in transwell inserts for simulating CNS infections. EV71 virions and small extracellular vesicles (sEVs) derived from EV71-infected cells (EV71-sEVs) were isolated from the cell culture supernatant by density gradient centrifugation. The BBB model was separately infected with EV71 virions and EV71-sEVs. The mechanism of crossing the BBB was determined by inhibiting the different endocytic modes. A murine model of EV71 infection was constructed for confirming the results of in vitro experiments.

RESULTS

The EV71-sEVs containing viral components were endocytosed by BMECs and released on the abluminal side of the BBB model, where they infected the astrocytes without disrupting the BBB in the early stages of infection. The integrity of the tight junctions (TJs) between BMECs was breached via downregulation of PI3K/Akt signaling in the late stages of infection.

CONCLUSIONS

EV71 utilized the circulating sEVs for infecting the CNS by crossing the BBB.

MRI characteristics of ventral vertebral venous plexus occlusion due to lymphoma in a large breed dog

Intravascular lymphoma is a rare presentation of lymphoma with a predilection to the central nervous system (CNS). A 9-year-old male-neutered Collie presented with a 3-month history of lymphadenopathy and a 6-day history of an acute onset, progressive, painful, symmetrical L4-S3 myelopathy. Magnetic resonance imaging revealed multifocal extradural spinal cord compressions from L3 to L6 secondary to a bilaterally enlarged and occluded ventral vertebral venous plexus (VVVP). Histopathology revealed low-grade lymphoma within the venous plexus in the lumbar vertebral column, tracheobronchial lymph nodes, and tonsils. Intravascular lymphoma should be considered a differential diagnosis for enlarged VVVP causing compression of the spinal cord.

Effect of Renal Ischemia Reperfusion on Brain Neuroinflammation

Acute kidney injury (AKI) is an inflammatory sequence. It can lead to distant organ injury, including damage to the central nervous system (CNS), mediated by increased circulating cytokines and other inflammatory mediators. It can also lead to increased blood-brain barrier (BBB) permeability. However, the effect of AKI on the inflammatory response of the brain has not yet been investigated. Therefore, we observed the effect of AKI on BBB permeability, microglia and astrocyte activation, and neuronal toxicity in the brain. The striatum and ventral midbrain, known to control overall movement, secrete the neurotransmitter dopamine. The activation of microglia and astrocytes present in this area causes neuro-degenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). The activation of astrocytes and microglia in the hippocampus and cerebral cortex, which are responsible for important functions, including memory, learning, concentration, and language, can trigger nerve cell apoptosis. The activation of astrocytes and microglia at this site is also involved in the inflammatory response associated with the accumulation of beta-amyloid. In the situation of kidney ischemia reperfusion (IR)-induced AKI, activation of microglia and astrocytes were observed in the striatum, ventral midbrain, hippocampus, and cortex. However, neuronal cell death was not observed until 48 h.

Epstein-Barr Virus Detection in the Central Nervous System of HIV-Infected Patients

Simply detecting Epstein-Barr virus deoxyribonucleic acid (EBV-DNA) is insufficient to diagnose EBV-associated diseases. The current literature around EBV-DNA detection from cerebrospinal fluid (CSF) in human immunodeficiency virus (HIV)-positive non-lymphoma patients was systematically reviewed and a meta-analysis reporting the estimated pooled prevalence in this population when PCR methods are employed, targeting different sequence segments within the EBV genome, was conducted. Using a combination of three key concepts-Epstein-Barr virus detection, central nervous system disease, and human cerebrospinal fluid-and their MeSH terms, the PubMed database was searched. A total of 273 papers reporting the detection of EBV in CNS were screened, of which 13 met the inclusion criteria. The meta-analysis revealed a pooled prevalence of EBV-DNA in CSF of 20% (CI: 12-31%). The highest pooled prevalence was from studies conducted on the African population at 39% (CI: 27-51%). The investigation of the presence of EBV-DNA in the CSF was also very varied, with several gene targets used. While most patients from the articles included in this review and meta-analysis were symptomatic of CNS disorders, the pathogenicity of EBV in non-lymphoma HIV patients when detected in CSF has still not been determined. The presence of EBV-DNA in the CNS remains a concern, and further research is warranted to understand its significance in causing CNS disorders.

Near-Infrared Photothermally Enhanced Photo-Oxygenation for Inhibition of Amyloid-β Aggregation Based on RVG-Conjugated Porphyrinic Metal-Organic Framework and Indocyanine Green Nanoplatform

Amyloid aggregation is associated with many neurodegenerative diseases such as Alzheimer's disease (AD). The current technologies using phototherapy for amyloid inhibition are usually photodynamic approaches based on evidence that reactive oxygen species can inhibit Aβ aggregation. Herein, we report a novel combinational photothermally assisted photo-oxygenation treatment based on a nano-platform of the brain-targeting peptide RVG conjugated with the 2D porphyrinic PCN-222 metal-organic framework and indocyanine green (PCN-222@ICG@RVG) with enhanced photo-inhibition in Alzheimer's Aβ aggregation. A photothermally assisted photo-oxygenation treatment based on PCN@ICG could largely enhance the photo-inhibition effect on Aβ₄₂ aggregation and lead to much lower neurotoxicity upon near-infrared (NIR) irradiation at 808 nm compared with a single modality of photo-treatment in both cell-free and in vitro experiments. Generally, local photothermal heat increases the instability of Aβ aggregates and keeps Aβ in the status of monomers, which facilitates the photo-oxygenation process of generating oxidized Aβ monomers with low aggregation capability. In addition, combined with the brain-targeting peptide RVG, the PCN-222@ICG@RVG nanoprobe shows high permeability of the human blood-brain barrier (BBB) on a human brain-on-a-chip platform. The ex vivo study also demonstrates that NIR-activated PCN-222@ICG@RVG could efficiently dissemble Aβ plaques. Our work suggests that the combination of photothermal treatment with photo-oxygenation can synergistically enhance the inhibition of Aβ aggregation, which may boost NIR-based combinational phototherapy of AD in the future.

Hepatitis E virus infects brain microvascular endothelial cells, crosses the blood-brain barrier, and invades the central nervous system

Hepatitis E virus (HEV) causes not only acute and chronic hepatitis but also neurological disorders. To delineate the mechanism of HEV-associated neurological diseases, we showed that both quasi-enveloped and nonenveloped HEVs can cross the blood–brain barrier model in a tumor necrosis factor alpha (TNF-α)-independent manner and productively infect brain microvascular endothelial cells in vitro. Furthermore, we showed that HEV was detected in brain and spinal cord from HEV-infected pigs and that pigs with detectable HEV in central nervous system (CNS) tissues had histological lesions in brain and spinal cord and significantly higher levels of proinflammatory cytokines TNF-α and interleukin 18 than pigs without detectable HEV in CNS tissues. The results shed light on a potential mechanism of HEV-associated neuroinvasion.

Hepatitis E virus (HEV) is an important but understudied zoonotic virus causing both acute and chronic viral hepatitis. A proportion of HEV-infected individuals also developed neurological diseases such as Guillain–Barré syndrome, neuralgic amyotrophy, encephalitis, and myelitis, although the mechanism remains unknown. In this study, by using an in vitro blood–brain barrier (BBB) model, we first investigated whether HEV can cross the BBB and whether the quasi-enveloped HEV virions are more permissible to the BBB than the nonenveloped virions. We found that both quasi-enveloped and nonenveloped HEVs can similarly cross the BBB and that addition of proinflammatory cytokine tumor necrosis factor alpha (TNF-α) has no significant effect on the ability of HEV to cross the BBB in vitro. To explore the possible mechanism of HEV entry across the BBB, we tested the susceptibility of human brain microvascular endothelial cells lining the BBB to HEV infection and showed that brain microvascular endothelial cells support productive HEV infection. To further confirm the in vitro observation, we conducted an experimental HEV infection study in pigs and showed that both quasi-enveloped and nonenveloped HEVs invade the central nervous system (CNS) in pigs, as HEV RNA was detected in the brain and spinal cord of infected pigs. The HEV-infected pigs with detectable viral RNA in CNS tissues had histological lesions in brain and spinal cord and significantly higher levels of proinflammatory cytokines TNF-α and interleukin 18 than the HEV-infected pigs without detectable viral RNA in CNS tissues. The findings suggest a potential mechanism of HEV-associated neuroinvasion.

Screening for neurodegeneration in Langerhans cell histiocytosis with neurofilament light in plasma

Patients with Langerhans cell histiocytosis (LCH) may develop progressive neurodegeneration in the central nervous system (ND‐CNS‐LCH). Neurofilament light protein (NFL) in cerebrospinal fluid (CSF) is a promising biomarker to detect and monitor ND‐CNS‐LCH. We compared paired samples of NFL in plasma (p‐NFL) and CSF in 10 patients (19 samples). Nine samples had abnormal CSF‐NFL (defined as ≥380 ng/l) with corresponding p‐NFL ≥ 2 ng/l. Ten samples had CSF‐NFL < 380 ng/l; eight (80%) with p‐NFL < 2 ng/l (p < 0.001; Fisher's exact test). Thus, our results suggest that p‐NFL may be used to screen for ND‐CNS‐LCH. Further studies are encouraged, including the role of p‐NFL for monitoring of ND‐CNS‐LCH.

Poloxamer 188 (P188), A Potential Polymeric Protective Agent for Central Nervous System Disorders: A Systematic Review

Poloxamer 188 (P188) is an FDA-approved biocompatible block copolymer composed of repeating units of Poly(Ethylene Oxide) (PEO) and poly(propylene oxide) (PPO). Due to its amphiphilic nature and high Hydrophile-Lipophile Balance (HLB) value of 29, P188 is used as a stabilizer/emulsifier in many cosmetics and pharmaceutical preparations. While the applications of P188 as an excipient are widely explored, the data on the pharmacological activity of P188 are scarce. Notably, the neuroprotective potential of P188 has gained a lot of interest. Therefore, this systematic review is aimed at summarizing evidence of neuroprotective potential of P188 in CNS disorders. The PRISMA model was used, and five databases (Google Scholar, Scopus, Wiley Online Library, ScienceDirect, and PubMed) were searched with relevant keywords. The search resulted in 11 articles, which met the inclusion criteria. These articles described the protective effects of P188 on traumatic brain injury or mechanical injury in cells, neurotoxicity, Parkinson's disease, Amyotrophic lateral sclerosis (ALS), and ischemia/ reperfusion injury from stroke. All the articles were original research in experimental or pre-clinical stages using animal models or in vitro systems. The reported activities demonstrated the potential of P188 as a neuroprotective agent in improving CNS conditions such as neurodegeneration.

Risdiplam: an investigational motor neuron-2 (SMN-2) splicing modifier for spinal muscular atrophy (SMA)

INTRODUCTION

Spinal muscular atrophy (SMA) is a rare autosomal recessive neuromuscular disease which is characterized by muscle atrophy and early death in most patients. Risdiplam is the third overall and first oral drug approved for SMA with disease-modifying potential. Risdiplam acts as a survival motor neuron 2 (SMN2) pre-mRNA splicing modifier with satisfactory safety and efficacy profile. This review aims to critically appraise the place of risdiplam in the map of SMA therapeutics.

AREAS COVERED

This review gives an overview of the current market for SMA and presents the mechanism of action and the pharmacological properties of risdiplam. It also outlines the development of risdiplam from early preclinical stages through to the most recently published results from phase 2/3 clinical trials. Risdiplam has proved its efficacy in pivotal trials for SMA Types 1, 2, and 3 with a satisfactory safety profile.

EXPERT OPINION

In the absence of comparative data with the other two approved drugs, the role of risdiplam in the treatment algorithm of affected individuals is examined in three different patient populations based on the age and diagnosis method (newborn screening or clinical, symptom-driven diagnosis). Long-term data and real-world data will play a fundamental role in its future.

Small but Mighty-Exosomes, Novel Intercellular Messengers in Neurodegeneration

Simple Summary

Exosomes are biological nanoparticles recently recognized as intercellular messengers. They contain a cargo of lipids, proteins, and RNA. They can transfer their content to not only cells in the vicinity but also to cells at a distance. This unique ability empowers them to modulate the physiology of recipient cells. In brain, exosomes play a role in neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease and amyotrophic lateral sclerosis.

Abstract

Exosomes of endosomal origin are one class of extracellular vesicles that are important in intercellular communication. Exosomes are released by all cells in our body and their cargo consisting of lipids, proteins and nucleic acids has a footprint reflective of their parental origin. The exosomal cargo has the power to modulate the physiology of recipient cells in the vicinity of the releasing cells or cells at a distance. Harnessing the potential of exosomes relies upon the purity of exosome preparation. Hence, many methods for isolation have been developed and we provide a succinct summary of several methods. In spite of the seclusion imposed by the blood–brain barrier, cells in the CNS are not immune from exosomal intrusive influences. Both neurons and glia release exosomes, often in an activity-dependent manner. A brief description of exosomes released by different cells in the brain and their role in maintaining CNS homeostasis is provided. The hallmark of several neurodegenerative diseases is the accumulation of protein aggregates. Recent studies implicate exosomes’ intercellular communicator role in the spread of misfolded proteins aiding the propagation of pathology. In this review, we discuss the potential contributions made by exosomes in progression of Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Understanding contributions made by exosomes in pathogenesis of neurodegeneration opens the field for employing exosomes as therapeutic agents for drug delivery to brain since exosomes do cross the blood–brain barrier.

Celsr family genes are dynamically expressed in embryonic and juvenile zebrafish

The Cadherin EGF LAG seven-pass G-type receptor (Celsr) family belongs to the adhesion G-protein coupled receptor superfamily. In most vertebrates, the Celsr family has three members (CELSR1-3), whereas zebrafish display four paralogues (celsr1a, 1b, 2, 3). Although studies have shown the importance of the Celsr family in planar cell polarity, axonal guidance, and dendritic growth, the molecular mechanisms of the Celsr family regulating these cellular processes in vertebrates remain elusive. Zebrafish is an experimentally more amenable model to study vertebrate development, as zebrafish embryos develop externally, optically transparent, remain alive with malformed organs, and zebrafish is genetically similar to humans. Understanding the detailed expression pattern is the first step of exploring the functional mechanisms of the genes involved in development. Thus, we report the spatiotemporal expression pattern of Celsr family members in zebrafish nervous tissues. Our analysis shows that celsr1b and celsr2 are expressed maternally. In embryos, celsr1a, celsr1b, and celsr2 are expressed in the neural progenitors, and celsr3 is expressed in all five primary neural clusters of the brain and mantle layer of the spinal cord. In juvenile zebrafish, celsr1a, celsr1b, and celsr2 are presumably expressed in the neural progenitor enriched regions of the CNS. Therefore, the expression pattern of zebrafish Celsr family members is reminiscent of patterns described in other vertebrates or mammalian speciate. This indicates the conserved role of Celsr family genes in nervous system development and suggests zebrafish as an excellent model to explore the cellular and molecular mechanisms of Celsr family genes in vertebrate neurogenesis. This article is protected by copyright. All rights reserved.

Identification of an Orally Bioavailable, Brain-Penetrant Compound with Selectivity for the Cannabinoid Type 2 Receptor

Modulation of the endocannabinoid system (ECS) is of great interest for its therapeutic relevance in several pathophysiological processes. The CB2 subtype is largely localized to immune effectors, including microglia within the central nervous system, where it promotes anti-inflammation. Recently, a rational drug design toward precise modulation of the CB2 active site revealed the novelty of Pyrrolo[2,1-c][1,4]benzodiazepines tricyclic chemotype with a high conformational similarity in comparison to the existing leads. These compounds are structurally unique, confirming their chemotype novelty. In our continuing search for new chemotypes as selective CB2 regulatory molecules, following SAR approaches, a total of 17 selected (S,E)-11-[2-(arylmethylene)hydrazono]-PBD analogs were synthesized and tested for their ability to bind to the CB1 and CB2 receptor orthosteric sites. A competitive [³H]CP-55,940 binding screen revealed five compounds that exhibited >60% displacement at 10 μM concentration. Further concentration-response analysis revealed two compounds, 4k and 4q, as potent and selective CB2 ligands with sub-micromolar activities (K_i = 146 nM and 137 nM, respectively). In order to support the potential efficacy and safety of the analogs, the oral and intravenous pharmacokinetic properties of compound 4k were sought. Compound 4k was orally bioavailable, reaching maximum brain concentrations of 602 ± 162 ng/g (p.o.) with an elimination half-life of 22.9 ± 3.73 h. Whether administered via the oral or intravenous route, the elimination half-lives ranged between 9.3 and 16.7 h in the liver and kidneys. These compounds represent novel chemotypes, which can be further optimized for improved affinity and selectivity toward the CB2 receptor.

Association of Dietary Prebiotic Consumption with Reduced Risk of Alzheimer's Disease in a Multiethnic Population

OBJECTIVE

This study aimed to investigate the association between dietary prebiotic intake and risk for Alzheimer's disease (AD).

METHODS

This longitudinal study includes 1,837 elderly (≥65 years) participants of a multi-ethnic community-based cohort study who were dementia-free at baseline and had provided dietary information from food frequency questionnaires. Total daily intake of fructan, one of the best-known prebiotics, was calculated based on consumption frequency and fructan content per serving of 8 food items. The associations of daily fructan intake with AD risk were examined using a Cox proportional hazards model, adjusted for cohort recruitment wave, age, gender, race/ethnicity, education, daily caloric intake, and APOE genotype. Effect modification by race/ethnicity, APOE genotype, and gender was tested by including an interaction term into the Cox models, as well as by stratified analyses.

RESULTS

Among 1,837 participants (1,263 women [69%]; mean [SD] age = 76 [6.3] years), there were 391 incident AD cases during a mean follow-up of 7.5 years (13736 person-years). Each additional gram of fructan intake was associated with 24% lower risk for AD ((95% CI)=0.60-0.97; P =0.03). Additional adjusting for smoking, alcohol consumption, and comorbidity index did not change results materially. The associations were not modified by race/ethnicity, gender, and APOE genotype, although stratified analyses showed that fructan intake was significantly associated with reduced AD risk in Hispanics but not in non-Hispanic Blacks or Whites.

CONCLUSION

Higher dietary fructan intake is associated with a reduced risk of clinical Alzheimer's disease among older adults.

Microbes, metabolites and (synaptic) malleability, oh my! The effect of the microbiome on synaptic plasticity

The microbiome influences the emotional and cognitive phenotype of its host, as well as the neurodevelopment and pathophysiology of various brain processes and disorders, via the well‐established microbiome–gut–brain axis. Rapidly accumulating data link the microbiome to severe neuropsychiatric disorders in humans, including schizophrenia, Alzheimer's and Parkinson's. Moreover, preclinical work has shown that perturbation of the microbiome is closely associated with social, cognitive and behavioural deficits. The potential of the microbiome as a diagnostic and therapeutic tool is currently undercut by a lack of clear mechanistic understanding of the microbiome–gut–brain axis. This review establishes the hypothesis that the mechanism by which this influence is carried out is synaptic plasticity – long‐term changes to the physical and functional neuronal structures that enable the brain to undertake learning, memory formation, emotional regulation and more. By examining the different constituents of the microbiome–gut–brain axis through the lens of synaptic plasticity, this review explores the diverse aspects by which the microbiome shapes the behaviour and mental wellbeing of the host. Key elements of this complex bi‐directional relationship include neurotransmitters, neuronal electrophysiology, immune mediators that engage with both the central and enteric nervous systems and signalling cascades that trigger long‐term potentiation of synapses. The importance of establishing mechanistic correlations along the microbiome–gut–brain axis cannot be overstated as they hold the potential for furthering current understanding regarding the vast fields of neuroscience and neuropsychiatry. This review strives to elucidate the promising theory of microbiome‐driven synaptic plasticity in the hope of enlightening current researchers and inspiring future ones.

Primary central nervous system sarcoma with DICER1 mutation-treatment results of a novel molecular entity in pediatric Peruvian patients

BACKGROUND

A high frequency of primary central nervous system (CNS) sarcomas was observed in Peru. This article describes the clinical characteristics, biological characteristics, and outcome of 70 pediatric patients.

METHODS

Data from 70 pediatric patients with primary CNS sarcomas diagnosed between January 2005 and June 2018 were analyzed. DNA methylation profiling from 28 tumors and gene panel sequencing from 27 tumors were available.

RESULTS

The median age of the patients was 6 years (range, 2-17.5 years), and 66 of 70 patients had supratentorial tumors. DNA methylation profiling classified 28 of 28 tumors as primary CNS sarcoma, DICER1 mutant. DICER1 mutations were found in 26 of 27 cases, TP53 mutations were found in 22 of 27 cases, and RAS-pathway gene mutations (NF1, KRAS, and NRAS) were found in 19 of 27 tumors, all of which were somatic (germline control available in 19 cases). The estimated incidence in Peru was 0.19 cases per 100,000 children (<18 years old) per year, which is significantly higher than the estimated incidence in Germany (0.007 cases per 100,000 children [<18 years] per year; P < .001). Patients with nonmetastatic disease (n = 46) that were treated with a combination therapy had a 2-year progression-free survival (PFS) rate of 58% (95% CI, 44%-76%) and a 2-year overall survival rate of 71% (95% CI, 57%-87%). PFS was the highest in patients treated with chemotherapy with ifosfamide, carboplatin, and etoposide (ICE) after upfront surgery followed by radiotherapy and ICE (2-year PFS, 79% [59%-100%], n = 18).

CONCLUSIONS

Primary CNS sarcoma with DICER1 mutation has an aggressive clinical course. A combination of surgery, chemotherapy, and radiotherapy seems beneficial. An underlying cancer predisposition syndrome explaining the increased incidence in Peruvian patients has not been identified so far.

LAY SUMMARY

A high incidence of primary pediatric central nervous system sarcomas in the Peruvian population is described. Using sequencing technologies and DNA methylation profiling, it is confirmed that these tumors molecularly belong to the recently proposed entity "primary central nervous system sarcomas, DICER1 mutant." Unexpectedly, DICER1 mutations as well as all other defining tumor mutations (TP53 mutations and RAS-pathway mutations) were not inherited in all 19 patients where analyzation was possible. These tumors have an aggressive clinical course. Multimodal combination therapy based on surgery, ifosfamide, carboplatin, and etoposide chemotherapy, and local radiotherapy leads to superior outcomes.

BCI-Based Control for Ankle Exoskeleton T-FLEX: Comparison of Visual and Haptic Stimuli with Stroke Survivors

Brain–computer interface (BCI) remains an emerging tool that seeks to improve the patient interaction with the therapeutic mechanisms and to generate neuroplasticity progressively through neuromotor abilities. Motor imagery (MI) analysis is the most used paradigm based on the motor cortex’s electrical activity to detect movement intention. It has been shown that motor imagery mental practice with movement-associated stimuli may offer an effective strategy to facilitate motor recovery in brain injury patients. In this sense, this study aims to present the BCI associated with visual and haptic stimuli to facilitate MI generation and control the T-FLEX ankle exoskeleton. To achieve this, five post-stroke patients (55–63 years) were subjected to three different strategies using T-FLEX: stationary therapy (ST) without motor imagination, motor imagination with visual stimulation (MIV), and motor imagination with visual-haptic inducement (MIVH). The quantitative characterization of both BCI stimuli strategies was made through the motor imagery accuracy rate, the electroencephalographic (EEG) analysis during the MI active periods, the statistical analysis, and a subjective patient’s perception. The preliminary results demonstrated the viability of the BCI-controlled ankle exoskeleton system with the beta rebound, in terms of patient’s performance during MI active periods and satisfaction outcomes. Accuracy differences employing haptic stimulus were detected with an average of 68% compared with the 50.7% over only visual stimulus. However, the power spectral density (PSD) did not present changes in prominent activation of the MI band but presented significant variations in terms of laterality. In this way, visual and haptic stimuli improved the subject’s MI accuracy but did not generate differential brain activity over the affected hemisphere. Hence, long-term sessions with a more extensive sample and a more robust algorithm should be carried out to evaluate the impact of the proposed system on neuronal and motor evolution after stroke.

Emerging roles of Dectin-1 in noninfectious settings and in the CNS

Dectin-1 is a C-type lectin receptor (CLR) expressed on the surface of various mammalian myeloid cells. Dectin-1 recognizes β-glucans and elicits antifungal proinflammatory immune responses. Recent studies have begun to examine the biology of Dectin-1 in previously less explored settings, such as homeostasis, sterile inflammation, and in the central nervous system. Indeed, in certain contexts, Dectin-1 is now known to promote tolerance, and anti-inflammatory and neuroprotective responses. In this review, we provide an overview of the current understanding of the roles of Dectin-1 in immunology beyond the context of fungal infections, mainly focusing on in vivo neuroimmunology studies, which could reveal new therapeutic approaches to modify innate immune responses in neurologic disorders.

Next generation sequencing for diagnosis of central nervous system aspergillosis in liver transplant recipients

Background

Fungal encephalitis is uncommon and sometimes fatal in liver transplant (LT) recipients. Early diagnosis of central nervous system (CNS) fungal infections, especially aspergillosis, is difficult based on routine tests of cerebrospinal fluid (CSF) alone. Next-generation sequencing (NGS) as a new tool may help in this respect.

Methods

Shotgun metagenomics was used to detect pathogens in CSF of patients, who were clinically suspected of CNS infection. Sequencing was performed at BGIseq-50 platform (BGI, Shenzhen).

Results

NGS technique identified Aspergillus in CSF of 5 patients, who were suspected of CNS infection, although clinical symptoms of these patients varied dramatically. The resulting sequence reads corresponding to Aspergillus species ranged from 2 to 25, with genomic coverage ranging from 0.0003% to 0.0036%. Rapid identification of Aspergillus enabled early appropriate antifungal therapy, although 4 patients eventually died of severe infection.

Conclusions

This is the first study to highlight the utility of NGS in early diagnosis of CNS aspergillosis in LT recipients. This new tool may be helpful in improving the diagnosis of CNS aspergillosis.

GSK-3β, FYN, and DYRK1A: Master Regulators in Neurodegenerative Pathways

Protein kinases (PKs) have been recognized as central nervous system (CNS)-disease-relevant targets due to their master regulatory role in different signal transduction cascades in the neuroscience space. Among them, GSK-3β, FYN, and DYRK1A play a crucial role in the neurodegeneration context, and the deregulation of all three PKs has been linked to different CNS disorders with unmet medical needs, including Alzheimer’s disease (AD), Parkinson’s disease (PD), frontotemporal lobar degeneration (FTLD), and several neuromuscular disorders. The multifactorial nature of these diseases, along with the failure of many advanced CNS clinical trials, and the lengthy approval process of a novel CNS drug have strongly limited the CNS drug discovery. However, in the near-decade from 2010 to 2020, several computer-assisted drug design strategies have been combined with synthetic efforts to develop potent and selective GSK-3β, FYN, and DYRK1A inhibitors as disease-modifying agents. In this review, we described both structural and functional aspects of GSK-3β, FYN, and DYRK1A and their involvement and crosstalk in different CNS pathological signaling pathways. Moreover, we outlined attractive medicinal chemistry approaches including multi-target drug design strategies applied to overcome some limitations of known PKs inhibitors and discover improved modulators with suitable blood–brain barrier (BBB) permeability and drug-like properties.

Emerging roles of IL-34 in neurodegenerative and neurological infectious disease

Neurological infections are often devastating in their clinical presentation. Although significant advances have made in neuroimaging techniques and molecular tools for diagnosis, as well as in anti-infective therapy, these diseases always difficult to diagnose and treat. Neuroparasitic infections and virus infections lead to neurological infections. In the nervous system, various cytokines and chemokines act as neuroinflammatory agents, neuromodulators, regulate neurodevelopment, and synaptic transmission. Among the most important cytokines, interleukins (ILs) are a large group of immunomodulatory proteins that elicit a wide variety of responses in cells and tissues. These ILs are involved in pro and anti-inflammatory effects, systemic inflammation, immune system modulation and play crucial roles in fighting cancer, infectious disease, and neurological disorders. Interleukin-34 (IL-34) identified by screening a comprehensive human protein library containing ∼3400 secreted and extracellular domain proteins in a human monocyte viability assay. Recent evidence has disclosed the crucial roles of IL-34 in the proliferation and differentiation of mononuclear phagocyte lineage cells, osteoclastogenesis, and inflammation. Additionally, IL-34 plays an important role in development, homeostasis, and disease. Dysregulation in IL-34 function can lead to various inflammatory and infectious diseases (e.g. Inflammatory bowel disease, liver fibrosis, Systemic Lupus erythematosus, rheumatoid arthritis), neurological disorders (e.g. Alzheimer disease) and neurological infectious disease (e.g. West Nile virus disease). In this review, we explore the biological role of IL-34 in addition to various impairments caused by dysregulation in IL-34 and discuss their potential links that may lead to important therapeutic and/or preventive strategies for these disorders.

Diversity of Adult Neural Stem and Progenitor Cells in Physiology and Disease

Adult neural stem and progenitor cells (NSPCs) contribute to learning, memory, maintenance of homeostasis, energy metabolism and many other essential processes. They are highly heterogeneous populations that require input from a regionally distinct microenvironment including a mix of neurons, oligodendrocytes, astrocytes, ependymal cells, NG2+ glia, vasculature, cerebrospinal fluid (CSF), and others. The diversity of NSPCs is present in all three major parts of the CNS, i.e., the brain, spinal cord, and retina. Intrinsic and extrinsic signals, e.g., neurotrophic and growth factors, master transcription factors, and mechanical properties of the extracellular matrix (ECM), collectively regulate activities and characteristics of NSPCs: quiescence/survival, proliferation, migration, differentiation, and integration. This review discusses the heterogeneous NSPC populations in the normal physiology and highlights their potentials and roles in injured/diseased states for regenerative medicine.