Neurodegeneration In Central Nervous System Research Articles

A phase II trial examining the safety and preliminary efficacy of repetitive transcranial magnetic stimulation (rTMS) for people living with multiple sclerosis

BackgroundMultiple sclerosis (MS) is a chronic neurological condition and the leading cause of non-traumatic disability in young adults. MS pathogenesis leads to the death of oligodendrocytes, demyelination, and progressive central nervous system neurodegeneration. Endogenous remyelination occurs in people with MS (PwMS) but is insufficient to repair the damage. Our preclinical studies in mice indicate that endogenous remyelination can be supported by the delivery of repetitive transcranial magnetic stimulation (rTMS). Our phase I trial concluded that 20 sessions of rTMS, delivered over 5 weeks, are safe and feasible for PwMS. This phase II trial aims to investigate the safety and preliminary efficacy of rTMS for PwMS.MethodsParticipants must be aged 18–65 years, diagnosed with MS by a neurologist, stable and relapse free for 6 months, have an Extended Disability Status Scale (EDSS) between 1.5 and 6 (inclusive), willing to travel to a study site every weekday for 4 consecutive weeks, and able to provide informed consent and access the internet. Participants from multiple centres will be randomised 2:1 (rTMS to sham) stratified by sex.The intervention will be delivered with a Magstim Rapid2 stimulator device and circular 90-mm coil or MagVenture MagPro stimulator device with C100 circular coil, positioned to stimulate a broad area including frontal and parietal cortices. For the rTMS group, pulse intensity will be set at 18% (MagVenture) or 25% (Magstim) of maximum stimulator output (MSO), and rTMS applied as intermittent theta burst stimulation (iTBS) (~ 3 min per side; 600 pulses). For the sham group, the procedure will be the same, but the intensity is set at 0%. Each participant will attend 20 intervention sessions over a maximum of 5 weeks.Outcome measures include MS Functional Composite Score (primary), Fatigue Severity Scale, Hospital Anxiety and Depression Scale, Quality of Life, and Pittsburgh Sleep Quality Index/Numeric Rating Scale and adverse events (secondary) and advanced MRI metrics (tertiary). Outcomes will be measured at baseline and after completing the intervention.DiscussionThis study will determine if rTMS can improve functional outcomes or other MS symptoms and determine whether rTMS has the potential to promote remyelination in PwMS.Trial registrationRegistered with Australian New Zealand Clinical Trials Registry, 20 January 2022; ACTRN12622000064707.

Macrophages and HLA-Class II Alleles in Multiple Sclerosis: Insights in Therapeutic Dynamics.

Antigen presentation is a crucial mechanism that drives the T cell-mediated immune response and the development of Multiple Sclerosis (MS). Genetic alterations within the highly variable Major Histocompatibility Complex Class II (MHC II) have been proven to result in significant changes in the molecular basis of antigen presentation and the clinical course of patients with both Adult-Onset MS (AOMS) and Pediatric-Onset MS (POMS). Among the numerous polymorphisms of the Human Leucocyte Antigens (HLA), within MHC II complex, HLA-DRB1*15:01 has been labeled, in Caucasian ethnic groups, as a high-risk allele for MS due to the ability of its structure to increase affinity to Myelin Basic Protein (MBP) epitopes. This characteristic, among others, in the context of the trimolecular complex or immunological synapsis, provides the foundation for autoimmunity triggered by environmental or endogenous factors. As with all professional antigen presenting cells, macrophages are characterized by the expression of MHC II and are often implicated in the formation of MS lesions. Increased presence of M1 macrophages in MS patients has been associated both with progression and onset of the disease, each involving separate but similar mechanisms. In this critical narrative review, we focus on macrophages, discussing how HLA genetic alterations can promote dysregulation of this population's homeostasis in the periphery and the Central Nervous System (CNS). We also explore the potential interconnection in observed pathological macrophage mechanisms and the function of the diverse structure of HLA alleles in neurodegenerative CNS, seen in MS, by comparing available clinical with molecular data through the prism of HLA-immunogenetics. Finally, we discuss available and experimental pharmacological approaches for MS targeting the trimolecular complex that are based on cell phenotype modulation and HLA genotype involvement and try to reveal fertile ground for the potential development of novel drugs.

Naujųjų anti-CD20 monokloninių antikūnų vaidmuo gydant itin aktyvią recidyvuojančiąją remituojančiąją išsėtinę sklerozę: ofatumumabo klinikinis efektyvumas ir saugumas

Multiple sclerosis is the most common chronic demyelinating neurodegenerative central nervous system disease among young adults. Considering its extent in a relatively young population, multiple sclerosis determines a significant socioeconomic burden to the society due to the cost of disease modifying treatment and a lower working capacity of patients and their caregivers. It is important to control neuroinflammation in the central nervous system caused by the pathologic activity of immune cells by considering a high efficacy treatment early in the disease course in order to prevent accumulation of neurological damage and to improve long term outcomes. According to the newest clinical studies, anti-CD20 therapies have proven their effectiveness and safety in active relapsing multiple sclerosis treatment: since 2018, ocrelizumab, and, since 2023, ofatumumab have both been available as treatment options in Lithuania. Because of its high potency and safety, as well as the specific mechanism of action, ofatumumab is effective in lower doses, and, after initial training at a health care facility, it can be self-administered through subcutaneous injection. This article reviews the efficacy, safety data and treatment indications of the latest available anti-CD20 monoclonal antibodies.

The Immunomodulatory Potential of Short-Chain Fatty Acids in Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative central nervous system (CNS) disorder, characterized by focal inflammation, demyelination, irreversible axonal loss and neurodegeneration. The proposed mechanism involves auto-reactive T lymphocytes crossing the blood-brain barrier (BBB), contributing to inflammation and demyelination. Pro-inflammatory Th1 and Th17 lymphocytes are pivotal in MS pathogenesis, highlighting an imbalanced interaction with regulatory T cells. Dysbiosis in the gut microbiota, characterized by microbial imbalance is implicated in systemic inflammation, yet its exact role in MS remains elusive. Short-chain fatty acids (SCFAs), including valerate, butyrate, propionate, and acetate, produced through dietary fiber fermentation by the gut microbiota, modulate inflammation and immune responses. Particularly, butyrate and propionate exhibit pronounced anti-inflammatory effects in both the gut and CNS. These SCFAs influence regulatory T lymphocyte expression and BBB permeability. This review discusses the potential therapeutic implications of SCFA in MS, highlighting their ability to modulate the gut-brain axis and restore immune balance.

New Insights into Microglia as Therapeutic Targets in Alzheimer’s Disease

Abstract: Alzheimer's disease (AD) is the most common neurodegenerative disease, accounting for 60–70% of dementia cases globally. Inflammation of the central nervous system (CNS) caused by microglia is a common characteristic of neurodegenerative illnesses such as Parkinson's disease and AD. Research has recently examined the relationship between neurodegenerative diseases and CNS microglia. Microglial cells comprise 10–15% of all CNS cells and are brain-resident myeloid cells mediating critical processes to support the CNS. Microglia have a variety of receptors that operate as molecular sensors, detecting exogenous and endogenous CNS injuries and triggering an immune response. Microglia serve as brain guardians by boosting phagocytic clearance and providing trophic support to enable tissue repair and maintain cerebral homeostasis, in addition to their traditional immune cell activity. At rest, microglia manage CNS homeostasis by phagocytic action, which removes pathogens and cell debris. Microglia cells that have been "resting" convert into active cells that create inflammatory mediators, protecting neurons and protecting against invading pathogens. Neuronal damage and neurodegenerative disorders are caused by excessive inflammation. Different microglial cells reply at different phases of the disease can lead to new therapy options and reduced inflammatory activity. This review focuses on the potential function of microglia, microglia subtypes, and M1/M2 phenotypic changes associated with neurodegenerative disorders. Microglial membrane receptors, the involvement of microglia in neuroinflammation, microglial targets in AD and the double role of microglia in AD pathogenesis are also discussed in this review.

Botulinum Neurotoxin Induces Neurotoxic Microglia Mediated by Exogenous Inflammatory Responses.

Botulinum neurotoxin serotype A (BoNT/A) is widely used in therapeutics and cosmetics. The effects of multi-dosed BoNT/A treatment are well documented on the peripheral nervous system (PNS), but much less is known on the central nervous system (CNS). Here, the mechanism of multi-dosed BoNT/A leading to CNS neurodegeneration is explored by using the 3D human neuron-glia model. BoNT/A treatment reduces acetylcholine, triggers astrocytic transforming growth factor beta, and upregulates C1q, C3, and C5 expression, inducing microglial proinflammation. The disintegration of the neuronal microtubules is escorted by microglial nitric oxide, interleukin 1β, tumor necrosis factor α, and interleukin 8. The microglial proinflammation eventually causes synaptic impairment, phosphorylated tau (pTau) aggregation, and the loss of the BoNT/A-treated neurons. Taking a more holistic approach, the model will allow to assess therapeutics for the CNS neurodegeneration under the prolonged use of BoNT/A.

In silico approach of 2,5-Diketopiperazines from marine organisms to neurodegenerative diseases

In this paper we present an in silico studies of new biological active of 2,5-Diketopiperazines candidates, from Marine Organisms to neurodegenerative diseases particular for the neurodegenerative central nervous system to Alzheimer's, Huntington and Parkinson’s diseases. A total of 35 DKPs were studied, by structural similarity analysis obtained MAO-A/B, β/γ-Secretase, COX-1/2 enzymes targets obtained, to continue molecular docking studies compared to endogenous substrates and reference inhibitors, finding a multitarget potential to increase dopamine levels and decrease β-amyloid and PGE2 levels, which makes them excellent molecules for studies against neurodegenerative diseases. DKP4, DKP23 and DKP25 as inhibitors of the 6 enzymes and DKP15, DKP19, DKP21, DKP26 and DKP33 for β-Secretease specifically, the rest with multitarget potential, denoting that the DKP ring serves as a base to generate multitarget or unitarget compounds through modifications in substituents. Finally, DKPs present low bioaccumulation in the body, no toxicity, high feasibility of crossing hematoencephalic membrane and activity on the CNS, which makes them an interesting set of molecules for the search for alternatives against neurodegenerative diseases.

Tear fluid as a source of biomarkers for the neurodegeneration in central nervous system

Composition of tear fluid alter not only in ocular diseases but in systemic pathologic processes including central nervous system (CNS) disorders. It is due to the variety of regulatory pathways for the tear production with active participation of CNS. The review represent data about mechanisms of tear production regulation, sources of metabolites present in tears, alterations of tear fluid composition in Alzheimer’s and Parkinson diseases, multiple sclerosis and amyotrophic lateral sclerosis. These neurodegenerative diseases are accompanied by typical alteration of concentrations of different protein bioregulators (cytokines, growth factors, synucleins, etc.) and catecholamines. These alterations often correlate with ones in cerebrospinal fluid appearing even before the clinical manifestation of the disease. Thus tear fluid analyses is a promising non-invasive method for the early diagnostic, prognosis and monitoring of neurodegenerative diseases, and also for the personalized therapy. We tried to represent the most recent data because interest to this problem has increased during the last years, and our own data also.

Publicly available ex vivo transcriptomics datasets to explore CNS physiology and neurodegeneration: state of the art and perspectives.

The central nervous system (CNS) is characterized by an intricate composition of diverse cell types, including neurons and glia cells (astrocytes, oligodendrocytes, and microglia), whose functions may differ along time, between sexes and upon pathology. The advancements in high-throughput transcriptomics are providing fundamental insights on cell phenotypes, so that molecular codes and instructions are ever more described for CNS physiology and neurodegeneration. To facilitate the search of relevant information, this review provides an overview of key CNS transcriptomics studies ranging from CNS development to ageing and from physiology to pathology as defined for five neurodegenerative disorders and their relative animal models, with a focus on molecular descriptions whose raw data were publicly available. Accurate phenotypic descriptions of cellular states correlate with functional changes and this knowledge may support research devoted to the development of therapeutic strategies supporting CNS repair and function.

RISK FACTORS AND PREVENTION OF MULTIPLE SCLEROSIS

Multiple sclerosis (MS) is a chronic autoimmune-inflammatory disease that causes widespread neurodegeneration in central nervous system. The prevalence of MS is increasing worldwide, and the cause of the disease is still unclear. However, the role of a number of factors in developing MS has been studied. These include genetic factors, race and ethnicity, Epstein-Barr virus infection, geografic latitude, ultraviolet exposure, migration, low blood levels of vitamin D, female gender, diet, obesity, smoking, occupational exposure to toxic substances, stress, mycoplasma pneumonia infection, etc. The proposed literature review discusses studies on the study and prevention of risk factors for MS.

Renewal of oligodendrocyte lineage reverses dysmyelination and CNS neurodegeneration through corrected N-acetylaspartate metabolism.

Myelinating oligodendrocytes are essential for neuronal communication and homeostasis of the central nervous system (CNS). One of the most abundant molecules in the mammalian CNS is N-acetylaspartate (NAA), which is catabolized into L-aspartate and acetate by the enzyme aspartoacylase (ASPA) in oligodendrocytes. The resulting acetate moiety is thought to contribute to myelin lipid synthesis. In addition, affected NAA metabolism has been implicated in several neurological disorders, including leukodystrophies and demyelinating diseases such as multiple sclerosis. Genetic disruption of ASPA function causes Canavan disease, which is hallmarked by increased NAA levels, myelin and neuronal loss, large vacuole formation in the CNS, and early death in childhood. Although NAA's direct role in the CNS is inconclusive, in peripheral adipose tissue, NAA-derived acetate has been found to modify histones, a mechanism known to be involved in epigenetic regulation of cell differentiation. We hypothesize that a lack of cellular differentiation in the brain contributes to the disruption of myelination and neurodegeneration in diseases with altered NAA metabolism, such as Canavan disease. Our study demonstrates that loss of functional Aspa in mice disrupts myelination and shifts the transcriptional expression of neuronal and oligodendrocyte markers towards less differentiated stages in a spatiotemporal manner. Upon re-expression of ASPA, these oligodendrocyte and neuronal lineage markers are either improved or normalized, suggesting that NAA breakdown by Aspa plays an essential role in the maturation of neurons and oligodendrocytes. Also, this effect of ASPA re-expression is blunted in old mice, potentially due to limited ability of neuronal, rather than oligodendrocyte, recovery.

MiR-485 regulates Th17 generation and pathogenesis in experimental autoimmune encephalomyelitis through targeting STAT3

Experimental autoimmune encephalomyelitis (EAE) is an induced autoimmune disease widely used as an animal model for multiple sclerosis, which is mainly characterized by demyelination, axonal loss, as well as neurodegeneration of central nervous system (CNS). T-helper (Th) 17 cell that generate interleukin-17 (IL-17) plays a key role in its pathogenesis. Their activity and differentiation are tightly regulated by some cytokines and transcription factors. Certain microRNAs (miRNAs) are involved in the pathogenesis of various autoimmune disorders, including EAE. Our research detected a novel miRNA that can regulate EAE. According to the results, during EAE, the expression of miR-485 notably lowered, and STAT3 was significantly increased. It was discovered that miR-485 knockdown in vivo upregulated Th17-associated cytokines and aggravated EAE, while the overexpressed miR-485 down-regulated Th17-associated cytokines and mitigated EAE. The up-regulation of miRNA-485 in vitro inhibited Th17-associated cytokines expression within EAE CD4+ T cells. Furthermore, as revealed by target prediction and dual-luciferase reporter assays, miR-485 directly targets STAT3, a gene that encodes a protein responsible for Th17 generation. Overall, miR-485 exert vital functions in Th17 generation and EAE pathogenesis.

Complement Turning Violent in Ultra-Rare Genetic Disorder

Abstract Sandhoff disease (SD) is an ultra-rare lysosomal storage disorder (LSD), which affects ~ 1/1000, 000 live birth. SD is caused by genetic deficiency of beta (β) Hexosaminidase and resulting excess central nervous system (CNS) synthesis of GM2 ganglioside (GM2) and its impact on neuron death. The exact mechanisms underlying such GM2-driven neuron death are unknown in SD. Glucosylceramide (GC) induced complement 5a (C5a) and its C5aR1 activation causes tissue inflammation in experimental and clinical Gaucher disease. Additionally, C5a-C5aR1 axis was found to sparks CNS inflammation and neurodegeneration in several brain diseases including, intracerebral hemorrhage, traumatic brain injury, myasthenia gravis, amyotrophic lateral sclerosis, neuromyelitis optica spectrum, Alzheimer, and Huntington’s diseases. Here, we determined the increased brain levels of C5a and C5aR1 in a beta (β) hexosaminidase inhibitor (HABI)-induced experimental mouse model of SD, when compared to vehicle (PBS) injected WT control mice. Also, HABI-induced experimental mouse model of SD showed increased microglial cells activation, massive brain generation of pro-inflammatory cytokines and loss of neurons, when compared to vehicle injected WT mice. To assess the relevance of C5a-C5aR1 axis activation for brain inflammation in SD, we targeted β hexosaminidase with HAB-I in WT and C5aR1 −/−mice. Strikingly, as compared to HABI-injected WT mice, HABI-injected C5aR1 −/−mice caused marked reduction in microglial cell activation, brain production of pro-inflammatory cytokines, and the loss of neurons. These data suggest that the C5a-C5aR1 axis is a critical driver of neuroinflammation and neurodegeneration in SD. No Funding

Molecular mechanisms of neuroprotective offerings by rosmarinic acid against neurodegenerative and other CNS pathologies.

Rosmarinic acid (RA) is a natural phenolic compound present in culinary herbs of the Boraginaceae, Lamiaceae/Labiatae, and Nepetoideae families. While the medicinal applications of these plants have been known for ages, RA has only been relatively recently established as an effective ameliorative agent against various disorders including cardiac diseases, cancer, and neuropathologies. In particular, several studies have confirmed the neuroprotective potential of RA in multiple cellular and animal models, as well as in clinical studies. The neuroprotective effects mediated by RA stem from its multimodal actions on a plethora of cellular and molecular pathways; including oxidative, bioenergetic, neuroinflammatory, and synaptic signaling. In recent years, RA has garnered tremendous interest as an ideal therapeutic candidate for treating neurodegenerative diseases. This review first briefly discusses the pharmacokinetics of RA and then proceeds to detail the neuroprotective mechanisms of RA at the molecular levels. Finally, the authors focus on the ameliorative potential of RA against several central nervous system (CNS) disorders, ranging from neuropsychological stress and epilepsy to neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, Parkinson's disease, Lewy body dementia, and amyotrophic lateral sclerosis.

Controlling the Impact of Helicobacter pylori-Related Hyperhomocysteinemia on Neurodegeneration.

Helicobacter pylori infection consists a high global burden affecting more than 50% of the world's population. It is implicated, beyond substantiated local gastric pathologies, i.e., peptic ulcers and gastric cancer, in the pathophysiology of several neurodegenerative disorders, mainly by inducing hyperhomocysteinemia-related brain cortical thinning (BCT). BCT has been advocated as a possible biomarker associated with neurodegenerative central nervous system disorders such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and/or glaucoma, termed as "ocular Alzheimer's disease". According to the infection hypothesis in relation to neurodegeneration, Helicobacter pylori as non-commensal gut microbiome has been advocated as trigger and/or mediator of neurodegenerative diseases, such as the development of Alzheimer's disease. Among others, Helicobacter pylori-related inflammatory mediators, defensins, autophagy, vitamin D, dietary factors, role of probiotics, and some pathogenetic considerations including relevant involved genes are discussed within this opinion article. In conclusion, by controlling the impact of Helicobacter pylori-related hyperhomocysteinemia on neurodegenerative disorders might offer benefits, and additional research is warranted to clarify this crucial topic currently representing a major worldwide burden.

NEUROPROTECTIVE ACTIVITIES AND REPAIR MECHANISMS OF GINKGO BILOBA EXTRACT EGB 761 ON CNS INJURIES AND NEURODEGENERATIVE DISORDERS

With an increasing number of neurodegenerative diseases and brain injuries, the focus of the research using synthetic and herbal medicines with an objective to treat the existing problems in neuroscience is ever-increasing. The availability of natural resources, knowledge about ancient herbs, and the mechanisms underlying neurodegenerative disorders and brain injuries is essential to developing herbal supplements with the potential to treat brain diseases and injuries. Despite the variety of synthetically manufactured drugs for brain health, the need for herbal and natural supplements is ever-rising due to the adverse long-term side effects of synthetic drugs. Ginkgo biloba — an Asian plant that is known to possess various neuroprotective properties — has been used as a medicine, even before 1505 AD. G. biloba extract EGB761 has been known to treat and manage impaired nervous system disorders. The current review discusses the neuroprotective properties of G. biloba and its repair mechanisms against subarachnoid hemorrhage, central nervous system (CNS) injuries like traumatic brain injury, ischemic brain injury, early brain injury, spinal cord injury, hypoxia, neuronal apoptosis, neurodegenerative diseases like Alzheimer’s, Parkinson’s, neuroplasticity, neurogenesis, synaptogenesis and its free radical scavenging activity, and neuroleptic properties for a nutritional approach to manage neurodegenerative disorders and CNS injuries.

Fast and Sustained Axonal Growth by BDNF Released from Chitosan Microspheres.

Brain-derived neurotrophic factor (BDNF) regulates dendritic branching and dendritic spine morphology, as well as synaptic plasticity and long-term potentiation. Consequently, BDNF deficiency has been associated with some neurological disorders such as Alzheimer's, Parkinson's or Huntington's diseases. In contrast, elevated BDNF levels correlate with recovery after traumatic central nervous system (CNS) injuries. The utility of BDNF as a therapeutic agent is limited by its short half-life in a pathological microenvironment and its low efficacy caused by unwanted consumption of non-neuronal cells or inappropriate dosing. Here, we tested the activity of chitosan microsphere-encapsulated BDNF to prevent clearance and prolong the efficacy of this neurotrophin. Neuritic growth activity of BDNF release from chitosan microspheres was observed in the PC12 rat pheochromocytoma cell line, which is dependent on neurotrophins to differentiate via the neurotrophin receptor (NTR). We obtained a rapid and sustained increase in neuritic out-growth of cells treated with BDNF-loaded chitosan microspheres over control cells (p < 0.001). The average of neuritic out-growth velocity was three times higher in the BDNF-loaded chitosan microspheres than in the free BDNF. We conclude that the slow release of BDNF from chitosan microspheres enhances signaling through NTR and promotes axonal growth in neurons, which could constitute an important therapeutic agent in neurodegenerative diseases and CNS lesions.

Tissue-resident immune cells in the pathogenesis of multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS) in which genetic and environmental factors contribute to disease progression. Both innate and adaptive immune cells, including T cells, B cells, activated macrophages and microglia, have been identified to be involved in the pathogenesis of MS, leading to the CNS inflammation, neurodegeneration and demyelination. In recent years, there has been considerable progress in understanding the contribution of tissue-resident immune cells in the pathogenesis of MS. We performed a keyword-based search in PubMed database. We combined "multiple sclerosis" with keywords, such as tissue-resident memory T cells, microglia to search for relevant literatures in PubMed. In this review, we comprehensively describe the characteristics of tissue-resident memory T cells and microglia, summarize their role in the pathogenesis of MS, and discuss their interaction with other immune cells in the CNS.

Intravenous 2-hydroxypropyl-β-cyclodextrin (Trappsol® Cyclo™) demonstrates biological activity and impacts cholesterol metabolism in the central nervous system and peripheral tissues in adult subjects with Niemann-Pick Disease Type C1: Results of a phase 1 trial.

Niemann-Pick Disease Type C1 (NPC1) is a disorder of intracellular cholesterol and lipid trafficking that leads to the accumulation of cholesterol and lipids in the late endosomal/lysosomal compartment, resulting in systemic manifestations (including hepatosplenomegaly and lung infiltration) and neurodegeneration. Preclinical studies have demonstrated that systemically administered 2-hydroxypropyl-β-cyclodextrin (HPβCD; Trappsol® Cyclo™) restores cholesterol metabolism and homeostasis in peripheral organs and tissues and in the central nervous system (CNS). Here, we assessed the safety, pharmacokinetics, and pharmacodynamics of HPβCD in peripheral tissues and the CNS in adult subjects with NPC1. A Phase 1, randomized, double-blind, parallel group study enrolled 13 subjects with NPC1 who received either 1500 mg/kg or 2500 mg/kg HPβCD intravenously every 2 weeks for a total of 7 doses (14 weeks). Subjects were 18 years or older, with a confirmed diagnosis of NPC1 and evidence of systemic involvement on clinical assessment. Pharmacokinetic evaluations in plasma and cerebrospinal fluid (CSF) were performed at the first and seventh infusions. Pharmacodynamic assessments included biomarkers of systemic cholesterol synthesis (serum lathosterol) and degradation (serum 4β-hydroxycholesterol), secondary sphingomyelin storage (plasma lysosphingomyelin-509, now more accurately referred to as N-palmitoyl-O-phosphocholineserine [PPCS]), and CNS-specific biomarkers of neurodegeneration (CSF total Tau) and cholesterol metabolism (serum 24(S)-hydroxycholesterol [24(S)-HC]). Safety monitoring included assessments of liver and kidney function, infusion related adverse events, and hearing evaluations. Ten subjects completed the study, with 6 at the 1500 mg/kg dose and 4 at the 2500 mg/kg dose. One subject withdrew following the first infusion after experiencing hypersensitivity pneumonitis, and 2 subjects withdrew after meeting a stopping rule related to hearing loss. Overall, HPβCD had an acceptable safety profile. The observed pharmacokinetic profile of HPβCD was similar following the first and seventh infusions, with a plasma half-life of 2 h, a maximum concentration reached at 6 to 8 h, and no evidence of accumulation. Serum biomarkers of cholesterol metabolism showed reduced synthesis and increased degradation. Compared to Baseline, filipin staining of liver tissue showed significant reductions of trapped unesterified cholesterol at both dose levels at Week 14. Plasma PPCS levels were also reduced. HPβCD was detected at low concentrations in the CSF (maximum, 33 μM) at both dose levels and persisted longer in CSF than in plasma. Total Tau levels in CSF decreased in most subjects. Serum levels of 24(S)-HC, a cholesterol metabolite from the CNS that is exported across the blood-brain barrier and into the circulation, decreased after both the first and seventh doses. Hence, pharmacodynamic assessments in both peripheral and CNS-related tissue show target engagement. While not the aim of the study, subjects reported favorable impacts on their quality of life. The plasma pharmacokinetics and pharmacodynamics of HPβCD administered at two intravenous dose levels to subjects with NPC1 were comparable to those observed in preclinical models. HPβCD cleared cholesterol from the liver and improved peripheral biomarkers of cholesterol homeostasis. At low CSF concentrations, HPβCD appeared to be pharmacologically active in the CNS based on the increased efflux of 24(S)-HC and reduction in CSF total Tau, a biomarker of CNS neurodegeneration. These data support the initiation of longer-term clinical trials to evaluate the safety and efficacy of intravenous HPβCD in subjects with NPC1. (ClinicalTrials.gov numbers: present trial, NCT02939547; open-label extension of the present trial, NCT03893071; global pivotal trial, NCT04860960).

Bone Marrow-Derived BRAFV600E-Mutated Cells Drive Neurodegeneration in a Mouse Model of Langerhans Cell Histiocytosis

Progressive neurodegeneration is a devastating and ultimately fatal complication in some survivors of multi-system high-risk Langerhans Cell Histiocytosis (LCH). Patients often develop LCH-ND years after the diagnosis and successful treatment of their systemic disease, and mechanisms that underlie LCH-ND remain largely undefined. BRAFV600E+ myeloid cells have been identified in areas of active neurodegeneration. However, it is unclear if the cell of origin of this disease is mutated microglia or circulating peripheral LCH cells invading the brain tissue. Embryonic origin (e.g. microglia) versus hematopoietic origin (or both) is a critical question to be able to identify, prevent and cure LCH-ND. We therefore tested the ability of bone marrow (BM)-derived BRAFV600E cells to migrate to the brain in a mouse model. We used BM chimera to study the transition of BRAFV600E-mutated cells to the brain as well as mechanisms of neurologic damage therein. Therefore, WT mice were conditioned with head-shielded Total Body Irradiation (TBI) and transplanted with BM from SCLCre-ER-TxBRAFV600ExRosa26YFP [LCH chimera] or SCLCre-ER-TxBRAFWTxRosa26YFP [control chimera]. Cre-recombination was induced after an engraftment period of 4 weeks. Mice were analyzed 4 months after Tamoxifen induction. LCH chimera exhibit a parenchymal infiltration with BM-derived BRAFV600E+ macrophages 4 months after Cre-recombination while control chimera do not have substantial numbers of reporter-tagged cells in the brain. The localization pattern of BRAFV600E+ macrophages in the brain recapitulate the pattern observed in humans, i.e. in the Brain Stem and Cerebellum. BM-derived BRAFV600E+ macrophages accumulate at the interface between the bloodstream and the central nervous system (CNS) parenchyma with 10-fold higher frequency than BM-derived BRAFWT macrophages and are associated with signs of local inflammation, astrocyte activation and decline in Purkinje cell density. Finally, LCH chimera exhibit signs of neurologic impairment (e.g. ataxia, decreased strength) that was partially reversed by targeted treatment. We conclude that BRAFV600E+ BM-derived myeloid progenitors reproducibly invade brain parenchyma where they differentiate into macrophages and induce inflammation and CNS injury. These novel insights inform previously unrecognized pathogenic mechanisms for LCH, with clinical implications in predicting LCH-ND risk, surveillance strategies, and novel therapeutic opportunities. Further, these data demonstrate potential for MAPK activation in hematopoietic myeloid progenitors to drive CNS inflammation and neurodegeneration, which may impact a broad range of neuropathological conditions beyond LCH.