Safety, pharmacokinetic, and functional effects of the nogo-a monoclonal antibody in amyotrophic lateral sclerosis: a randomized, first-in-human clinical trial

Inter-Antibody Variability in the Clinical Pharmacokinetics of Monoclonal Antibodies Characterized Using Population Physiologically Based Pharmacokinetic Modeling

The objective of this work was to develop a population physiologically based pharmacokinetic (popPBPK) model to characterize the variability in the clinical PK of monoclonal antibodies (mAbs) following intravenous (IV) and subcutaneous (SC) administration. An extensive literature search was conducted and clinical PK data for FDA-approved as well as non-approved mAbs were collected. Training and validation datasets of 44 and 9 mAbs exhibiting linear pharmacokinetics were used for model development. The variability in antibody PK was captured by accounting for different rate constants of pinocytosis (CLup) and intracellular degradation (kdeg) for different mAbs. Typical values for CLup and kdeg and their respective inter-antibody variabilities (ωClup, ωKdeg) were estimated to be 0.32 L/h/L and 26.1 h-1 (73% and 46%). Varied absorption profiles following SC dosing were characterized by incorporating inter-antibody variability in local degradation (kSC) and rate of lymphatic uptake (S_Lu) of mAbs. Estimates for typical kSC and S_Lu values, and ωKsc,ωS_Lu, were found to be 0.0015 h-1 and 0.54 (193%, and 49%). FDA-approved mAbs showed less local degradation (0.0014 h-1 vs. 0.0038 h-1) compared with other clinically tested mAbs, whereas no substantial differences in physiological processes involved in disposition were observed. To evaluate the generalizability of estimated PK parameters and model validation, the final popPBPK model was used to simulate the range of expected PK for mAbs following SC administration of nine different mAbs that were not used for model-building purposes. The predicted PK of all nine mAbs was within the expected range specified a priori. Thus, the popPBPK model presented here may serve as a tool to predict the clinical PK of mAbs with linear disposition before administering them to humans. The model may also support preclinical-to-clinical translation and 'first-in-human' dose determination for mAbs.

Biomarkers in amyotrophic lateral sclerosis: current status and future prospects

Disease heterogeneity in amyotrophic lateral sclerosis poses a substantial challenge in drug development. Categorization based on clinical features alone can help us predict the disease course and survival, but quantitative measures are also needed that can enhance the sensitivity of the clinical categorization. In this Review, we describe the emerging landscape of diagnostic, categorical and pharmacodynamic biomarkers in amyotrophic lateral sclerosis and their place in the rapidly evolving landscape of new therapeutics. Fluid-based markers from cerebrospinal fluid, blood and urine are emerging as useful diagnostic, pharmacodynamic and predictive biomarkers. Combinations of imaging measures have the potential to provide important diagnostic and prognostic information, and neurophysiological methods, including various electromyography-based measures and quantitative EEG-magnetoencephalography-evoked responses and corticomuscular coherence, are generating useful diagnostic, categorical and prognostic markers. Although none of these biomarker technologies has been fully incorporated into clinical practice or clinical trials as a primary outcome measure, strong evidence is accumulating to support their clinical utility.

Therapeutic targeting of ALS pathways: Refocusing an incomplete picture

Numerous potential amyotrophic lateral sclerosis (ALS)-relevant pathways have been hypothesized and studied preclinically, with subsequent translation to clinical trial. However, few successes have been observed with only modest effects. Along with an improved but incomplete understanding of ALS as a neurodegenerative disease is the evolution of more sophisticated and diverse in vitro and in vivo preclinical modeling platforms, as well as clinical trial designs. We highlight proposed pathological pathways that have been major therapeutic targets for investigational compounds. It is likely that the failures of so many of these therapeutic compounds may not have occurred because of lack of efficacy but rather because of a lack of preclinical modeling that would help define an appropriate disease pathway, as well as a failure to establish target engagement. These challenges are compounded by shortcomings in clinical trial design, including lack of biomarkers that could predict clinical success and studies that are underpowered. Although research investments have provided abundant insights into new ALS-relevant pathways, most have not yet been developed more fully to result in clinical study. In this review, we detail some of the important, well-established pathways, the therapeutics targeting them, and the subsequent clinical design. With an understanding of some of the shortcomings in translational efforts over the last three decades of ALS investigation, we propose that scientists and clinicians may choose to revisit some of these therapeutic pathways reviewed here with an eye toward improving preclinical modeling, biomarker development, and the investment in more sophisticated clinical trial designs.

Central nervous system demyelinating diseases: glial cells at the hub of pathology

Inflammatory demyelinating diseases (IDDs) are among the main causes of inflammatory and neurodegenerative injury of the central nervous system (CNS) in young adult patients. Of these, multiple sclerosis (MS) is the most frequent and studied, as it affects about a million people in the USA alone. The understanding of the mechanisms underlying their pathology has been advancing, although there are still no highly effective disease-modifying treatments for the progressive symptoms and disability in the late stages of disease. Among these mechanisms, the action of glial cells upon lesion and regeneration has become a prominent research topic, helped not only by the discovery of glia as targets of autoantibodies, but also by their role on CNS homeostasis and neuroinflammation. In the present article, we discuss the participation of glial cells in IDDs, as well as their association with demyelination and synaptic dysfunction throughout the course of the disease and in experimental models, with a focus on MS phenotypes. Further, we discuss the involvement of microglia and astrocytes in lesion formation and organization, remyelination, synaptic induction and pruning through different signaling pathways. We argue that evidence of the several glia-mediated mechanisms in the course of CNS demyelinating diseases supports glial cells as viable targets for therapy development.

Unveiling the modulation of Nogo receptor in neuroregeneration and plasticity: Novel aspects and future horizon in a new frontier

Neurodegenerative diseases (NDs) such as Alzheimer's, Parkinson's, Multiple Sclerosis, Hereditary Spastic Paraplegia, and Amyotrophic Lateral Sclerosis have emerged as the most dreaded diseases due to a lack of precise diagnostic tools and efficient therapies. Despite the fact that the contributing factors of NDs are still unidentified, mounting evidence indicates the possibility that genetic and cellular changes may lead to the significant production of abnormally misfolded proteins. These misfolded proteins lead to damaging effects thereby causing neurodegeneration. The association between Neurite outgrowth factor (Nogo) with neurological diseases and other peripheral diseases is coming into play. Three isoforms of Nogo have been identified Nogo-A, Nogo-B and Nogo-C. Among these, Nogo-A is mainly responsible for neurological diseases as it is localized in the CNS (Central Nervous System), whereas Nogo-B and Nogo-C are responsible for other diseases such as colitis, lung, intestinal injury, etc. Nogo-A, a membrane protein, had first been described as a CNS-specific inhibitor of axonal regeneration. Several recent studies have revealed the role of Nogo-A proteins and their receptors in modulating neurite outgrowth, branching, and precursor migration during nervous system development. It may also modulate or affect the inhibition of growth during the developmental processes of the CNS. Information about the effects of other ligands of Nogo protein on the CNS are yet to be discovered however several pieces of evidence have suggested that it may also influence the neuronal maturation of CNS and targeting Nogo-A could prove to be beneficial in several neurodegenerative diseases.

Nogo-A and LINGO-1: Two Important Targets for Remyelination and Regeneration

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) that causes progressive neurological disability in most patients due to neurodegeneration. Activated immune cells infiltrate the CNS, triggering an inflammatory cascade that leads to demyelination and axonal injury. Non-inflammatory mechanisms are also involved in axonal degeneration, although they are not fully elucidated yet. Current therapies focus on immunosuppression; however, no therapies to promote regeneration, myelin repair, or maintenance are currently available. Two different negative regulators of myelination have been proposed as promising targets to induce remyelination and regeneration, namely the Nogo-A and LINGO-1 proteins. Although Nogo-A was first discovered as a potent neurite outgrowth inhibitor in the CNS, it has emerged as a multifunctional protein. It is involved in numerous developmental processes and is necessary for shaping and later maintaining CNS structure and functionality. However, the growth-restricting properties of Nogo-A have negative effects on CNS injury or disease. LINGO-1 is also an inhibitor of neurite outgrowth, axonal regeneration, oligodendrocyte differentiation, and myelin production. Inhibiting the actions of Nogo-A or LINGO-1 promotes remyelination both in vitro and in vivo, while Nogo-A or LINGO-1 antagonists have been suggested as promising therapeutic approaches for demyelinating diseases. In this review, we focus on these two negative regulators of myelination while also providing an overview of the available data on the effects of Nogo-A and LINGO-1 inhibition on oligodendrocyte differentiation and remyelination.

Comprehensive Research on Past and Future Therapeutic Strategies Devoted to Treatment of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a rapidly debilitating fatal neurodegenerative disorder, causing muscle atrophy and weakness, which leads to paralysis and eventual death. ALS has a multifaceted nature affected by many pathological mechanisms, including oxidative stress (also via protein aggregation), mitochondrial dysfunction, glutamate-induced excitotoxicity, apoptosis, neuroinflammation, axonal degeneration, skeletal muscle deterioration and viruses. This complexity is a major obstacle in defeating ALS. At present, riluzole and edaravone are the only drugs that have passed clinical trials for the treatment of ALS, notwithstanding that they showed modest benefits in a limited population of ALS. A dextromethorphan hydrobromide and quinidine sulfate combination was also approved to treat pseudobulbar affect (PBA) in the course of ALS. Globally, there is a struggle to prevent or alleviate the symptoms of this neurodegenerative disease, including implementation of antisense oligonucleotides (ASOs), induced pluripotent stem cells (iPSCs), CRISPR-9/Cas technique, non-invasive brain stimulation (NIBS) or ALS-on-a-chip technology. Additionally, researchers have synthesized and screened new compounds to be effective in ALS beyond the drug repurposing strategy. Despite all these efforts, ALS treatment is largely limited to palliative care, and there is a strong need for new therapeutics to be developed. This review focuses on and discusses which therapeutic strategies have been followed so far and what can be done in the future for the treatment of ALS.

Physiologically Based Modeling to Predict Monoclonal Antibody Pharmacokinetics in Humans from in vitro Physiochemical Properties

A model-based framework is presented to predict monoclonal antibody (mAb) pharmacokinetics (PK) in humans based on in vitro measures of antibody physiochemical properties. A physiologically based pharmacokinetic (PBPK) model is used to explore the predictive potential of 14 in vitro assays designed to measure various antibody physiochemical properties, including nonspecific cell-surface interactions, FcRn binding, thermal stability, hydrophobicity, and self-association. Based on the mean plasma PK time course data of 22 mAbs from humans reported in the literature, we found a significant positive correlation (R = 0.64, p = .0013) between the model parameter representing antibody-specific vascular to endothelial clearance and heparin relative retention time, an in vitro measure of nonspecific binding. We also found that antibody-specific differences in paracellular transport due to convection and diffusion could be partially explained by antibody heparin relative retention time (R = 0.52, p = .012). Other physiochemical properties, including antibody thermal stability, hydrophobicity, cross-interaction and self-association, in and of themselves were not predictive of model-based transport parameters. In contrast to other studies that have reported empirically derived expressions relating in vitro measures of antibody physiochemical properties directly to antibody clearance, the proposed PBPK model-based approach for predicting mAb PK incorporates fundamental mechanisms governing antibody transport and processing, informed by in vitro measures of antibody physiochemical properties, and can be expanded to include more descriptive representations of each of the antibody processing subsystems, as well as other antibody-specific information.

Antibody-Based Therapeutic Interventions for Amyotrophic Lateral Sclerosis: A Systematic Literature Review

Amyotrophic Lateral Sclerosis (ALS) is a mid-life onset neurodegenerative disease that manifests its symptomatology with motor impairments and cognitive deficits overlapping with Frontotemporal Lobar Degeneration (FTLD). The etiology of ALS remains elusive, with various mechanisms and cellular targets implicated, and no treatment can reverse or stop the progression of the pathology. Therapeutic interventions based on passive immunization are gaining attention for neurodegenerative diseases, and FDA recently approved the first antibody-based approach for Alzheimer's disease. The present systematic review of the literature aims to highlight the efforts made over the past years at developing antibody-based strategies to cure ALS. Thirty-one original research papers have been selected where the therapeutic efficacy of antibodies were investigated and described in patients and animal models of ALS. Antibody-based interventions analyzed, target both extracellular molecules implicated in the pathology and intracellular pathogenic proteins known to drive the disease, such as SOD1, TDP-43 or C9ORF72 repeats expansions. The potentials and limitations of these therapeutic interventions have been described and discussed in the present review.

The Implication of Reticulons (RTNs) in Neurodegenerative Diseases: From Molecular Mechanisms to Potential Diagnostic and Therapeutic Approaches

Reticulons (RTNs) are crucial regulatory factors in the central nervous system (CNS) as well as immune system and play pleiotropic functions. In CNS, RTNs are transmembrane proteins mediating neuroanatomical plasticity and functional recovery after central nervous system injury or diseases. Moreover, RTNs, particularly RTN4 and RTN3, are involved in neurodegeneration and neuroinflammation processes. The crucial role of RTNs in the development of several neurodegenerative diseases, including Alzheimer's disease (AD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), or other neurological conditions such as brain injury or spinal cord injury, has attracted scientific interest. Reticulons, particularly RTN-4A (Nogo-A), could provide both an understanding of early pathogenesis of neurodegenerative disorders and be potential therapeutic targets which may offer effective treatment or inhibit disease progression. This review focuses on the molecular mechanisms and functions of RTNs and their potential usefulness in clinical practice as a diagnostic tool or therapeutic strategy.

Targeting for Success: Demonstrating Proof-of-Concept with Mechanistic Early Phase Clinical Pharmacology Studies for Disease-Modification in Neurodegenerative Disorders

The clinical failure rate for disease-modifying treatments (DMTs) that slow or stop disease progression has been nearly 100% for the major neurodegenerative disorders (NDDs), with many compounds failing in expensive and time-consuming phase 2 and 3 trials for lack of efficacy. Here, we critically review the use of pharmacological and mechanistic biomarkers in early phase clinical trials of DMTs in NDDs, and propose a roadmap for providing early proof-of-concept to increase R&D productivity in this field of high unmet medical need. A literature search was performed on published early phase clinical trials aimed at the evaluation of NDD DMT compounds using MESH terms in PubMed. Publications were selected that reported an early phase clinical trial with NDD DMT compounds between 2010 and November 2020. Attention was given to the reported use of pharmacodynamic (mechanistic and physiological response) biomarkers. A total of 121 early phase clinical trials were identified, of which 89 trials (74%) incorporated one or multiple pharmacodynamic biomarkers. However, only 65 trials (54%) used mechanistic (target occupancy or activation) biomarkers to demonstrate target engagement in humans. The most important categories of early phase mechanistic and response biomarkers are discussed and a roadmap for incorporation of a robust biomarker strategy for early phase NDD DMT clinical trials is proposed. As our understanding of NDDs is improving, there is a rise in potentially disease-modifying treatments being brought to the clinic. Further increasing the rational use of mechanistic biomarkers in early phase trials for these (targeted) therapies can increase R&D productivity with a quick win/fast fail approach in an area that has seen a nearly 100% failure rate to date.

Neurite Outgrowth Inhibitor (NogoA) Is Upregulated in White Matter Lesions of Complex Cortical Malformations

Complex cortical malformations (CCMs), such as hemimegalencephaly and polymicrogyria, are associated with drug-resistant epilepsy and developmental impairment. They share certain neuropathological characteristics including mammalian target of rapamycin (mTOR) activation and an atypical number of white matter neurons. To get a better understanding of the pathobiology of the lesion architecture, we investigated the role of neurite outgrowth inhibitor A (NogoA), a known regulator of neuronal migration. Epilepsy surgery specimens from 16 CCM patients were analyzed and compared with sections of focal cortical dysplasia IIB (FCD IIB, n = 22), tuberous sclerosis complex (TSC, n = 8) as well as healthy controls (n = 15). Immunohistochemistry was used to characterize NogoA, myelination, and mTOR signaling. Digital slides were evaluated automatically with ImageJ. NogoA staining showed a significantly higher expression within the white matter of CCM and FCD IIB, whereas cortical tubers presented levels similar to controls. Further analysis of possible associations of NogoA with other factors revealed a positive correlation with mTOR and seizure frequency. To identify the main expressing NogoA cell type, double staining revealed dysmorphic neuronal white matter cells. Increased NogoA expression is associated with profound inhibition of neuritic sprouting and therefore contributes to a decrease in neuronal network complexity in CCM patients.

Monoclonal full-length antibody against TAR DNA binding protein 43 reduces related proteinopathy in neurons

Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), 2 incurable neurodegenerative disorders, share the same pathological hallmark named TDP43 (TAR DNA binding protein 43) proteinopathy. This event is characterized by a consistent cytoplasmic mislocalization and aggregation of the protein TDP43, which loses its physiological properties, leading neurons to death. Antibody-based approaches are now emerging interventions in the field of neurodegenerative disorders. Here, we tested the target specificity, in vivo distribution, and therapeutic efficacy of a monoclonal full-length antibody, named E6, in TDP43-related conditions. We observed that the antibody recognizes specifically the cytoplasmic fraction of TDP43. We demonstrated its ability in targeting large neurons in the spinal cord of mice and in reducing TDP43 mislocalization and NF-κB activation. We also recognized the proteasome as well as the lysosome machineries as possible mechanisms used by the antibody to reduce TDP43 proteinopathy. To our knowledge, this is the first report showing the therapeutic efficacy and feasibility of a full-length antibody against TDP43 in reducing TDP43 proteinopathy in spinal neurons of an ALS/FTLD mouse model.

A full-length antibody against TDP43 reduces TDP43 proteinopathy in spinal neurons of an amyotrophic lateral sclerosis/Frontotemporal lobar degeneration mouse model.

Translating concepts of neural repair after stroke: Structural and functional targets for recovery

Stroke is among the most common causes of adult disability worldwide, and its disease burden is shifting towards that of a long-term condition. Therefore, the development of approaches to enhance recovery and augment neural repair after stroke will be critical. Recovery after stroke involves complex interrelated systems of neural repair. There are changes in both structure (at the molecular, cellular, and tissue levels) and function (in terms of excitability, cortical maps, and networks) that occur spontaneously within the brain. Several approaches to augment neural repair through enhancing these changes are under study. These include identifying novel drug targets, implementing rehabilitation strategies, and developing new neurotechnologies. Each of these approaches has its own array of different proposed mechanisms. Current investigation has emphasized both cellular and circuit-based targets in both gray and white matter, including axon sprouting, dendritic branching, neurogenesis, axon preservation, remyelination, blood brain barrier integrity, blockade of extracellular inhibitory signals, alteration of excitability, and promotion of new brain cortical maps and networks. Herein, we review for clinicians recovery after stroke, basic elements of spontaneous neural repair, and ongoing work to augment neural repair. Future study requires alignment of basic, translational, and clinical research. The field continues to grow while becoming more clearly defined. As thrombolysis changed stroke care in the 1990 s and thrombectomy in the 2010 s, the augmentation of neural repair and recovery after stroke may revolutionize care for these patients in the coming decade.

A Review on the Etiology and Management of Pediatric Traumatic Spinal Cord Injuries

CONTEXT

Pediatric traumatic spinal cord injury (SCI) is an uncommon presentation in the emergency department. Severe injuries are associated with devastating outcomes and complications, resulting in high costs to both the society and the economic system.

EVIDENCE ACQUISITION

The data on pediatric traumatic spinal cord injuries has been narratively reviewed.

RESULTS

Pediatric SCI is a life-threatening emergency leading to serious outcomes and high mortality in children if not managed promptly. Pediatric SCI can impose many challenges to neurosurgeons and caregivers because of the lack of large studies with high evidence level and specific guidelines in terms of diagnosis, initial management and of in-hospital treatment options. Several novel potential treatment options for SCI have been developed and are currently under investigation. However, research studies into this field have been limited by the ethical and methodological challenges.

CONCLUSION

Future research is needed to investigate the safety and efficacy of the recent uprising neurodegenerative techniques in SCI population. Owing to the current limitations, there is a need to develop novel trial methodologies that can overcome the current methodological and ethical limitations.

Clinical neurophysiology of anterior horn cell disorders

The development of neurophysiological techniques for clinical assessment in the 20th century is closely related to the study of anterior horn cell diseases. The effects of motor axon loss on nerve conduction velocity and compound motor amplitude were elucidated first in amyotrophic lateral sclerosis (ALS), as was the characterization of reinnervation as detected by needle electromyography. The same changes noted in early studies still play a major role in the diagnosis of anterior horn cell diseases. In addition, much of modern neurophysiological assessment of motor axon quantitation, ion channel changes in neurogenic disease, and cortical physiology studies to assess both network and excitability abnormalities have all been applied to ALS. In this chapter, we summarize the clinical attributes of ALS and Spinal Muscular Atrophy, and review how clinical neurophysiology is employed in the clinical and the research setting.

The development of biological therapies for neurological diseases: moving on from previous failures

INTRODUCTION

Although years of research have expanded the use of biologics for several clinical conditions, such development has not yet occurred in the treatment of neurological diseases. With the advancement of biologic technologies, there is promise for these therapeutics as novel therapeutic approaches for neurological diseases. Areas covered: In this article, the authors review the therapeutic potential of different types of biologics for the treatment of neurological diseases. Preclinical and clinical studies that investigate the efficacy and safety of biologics in the treatment of neurological diseases, namely Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson disease, multiple sclerosis, and stroke, were reviewed. Moreover, the authors describe the key challenges in the development of therapeutically safe and effective biologics for the treatment of neurological diseases. Expert opinion: Several biologics have shown promise in the treatment of neurological diseases. However, the complexity of the CNS, as well as a limited understanding of disease progression, and restricted access of biologics to the CNS has limited successful development. Therefore, more research needs to be conducted to overcome these hurdles before developing effective and safe biologics for neurological diseases. The emergence of new technologies for the design, production and delivery of biologics will accelerate translating biologics to the clinic.

Opportunities and pitfalls in clinical proof-of-concept: principles and examples

Clinical proof-of-concept trials crucially inform major resource deployment decisions. This paper discusses several mechanisms for enhancing their rigour and efficiency. The importance of careful consideration when using a surrogate endpoint is illustrated; situational effectiveness of run-in patient enrichment is explored; a versatile tool is introduced to ensure a strong pharmacological underpinning; the benefits of dose-titration are revealed by simulation; and the importance of adequately scheduled observations is shown. The general process of model-based trial design and analysis is described and several examples demonstrate the value in historical data, simulation-guided design, model-based analysis and trial adaptation informed by interim analysis.

p75NTR and TROY: Uncharted Roles of Nogo Receptor Complex in Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), have been on the forefront of drug discovery for most of the myelin inhibitory molecules implicated in axonal regenerative process. Nogo-A along with its putative receptor NgR and co-receptor LINGO-1 has paved the way for the production of pharmaceutical agents such as monoclonal antibodies, which are already put into handful of clinical trials. On the other side, little progress has been made towards clarifying the role of neurotrophin receptor p75 (p75NTR) and TROY in disease progression, other key players of the Nogo receptor complex. Previous work of our lab has shown that their exact location and type of expression is harmonized in a phase-dependent manner. Here, in this review, we outline their façade in normal and diseased central nervous system (CNS) and suggest a role for p75NTR in chronic axonal regeneration whereas TROY in acute inflammation of EAE intercourse.

Blood-Brain Barrier Driven Pharmacoresistance in Amyotrophic Lateral Sclerosis and Challenges for Effective Drug Therapies

The blood-brain barrier (BBB) is essential for proper neuronal function, homeostasis, and protection of the central nervous system (CNS) microenvironment from blood-borne pathogens and neurotoxins. The BBB is also an impediment for CNS penetration of drugs. In some neurologic conditions, such as epilepsy and brain tumors, overexpression of P-glycoprotein, an efflux transporter whose physiological function is to expel catabolites and xenobiotics from the CNS into the blood stream, has been reported. Recent studies reported that overexpression of P-glycoprotein and increase in its activity at the BBB drives a progressive resistance to CNS penetration and persistence of riluzole, the only drug approved thus far for treatment of amyotrophic lateral sclerosis (ALS), rapidly progressive and mostly fatal neurologic disease. This review will discuss the impact of transporter-mediated pharmacoresistance for ALS drug therapy and the potential therapeutic strategies to improve the outcome of ALS clinical trials and efficacy of current and future drug treatments.

Spatiotemporal and Long Lasting Modulation of 11 Key Nogo Signaling Genes in Response to Strong Neuroexcitation

Inhibition of nerve growth and plasticity in the CNS is to a large part mediated by Nogo-like signaling, now encompassing a plethora of ligands, receptors, co-receptors and modulators. Here we describe the distribution and levels of mRNA encoding 11 key genes involved in Nogo-like signaling (Nogo-A, Oligodendrocyte-Myelin glycoprotein (OMgp), Nogo receptor 1 (NgR1), NgR2, NgR3, Lingo-1, TNF receptor orphan Y (Troy), Olfactomedin, Lateral olfactory tract usher substance (Lotus) and membrane-type matrix metalloproteinase-3 (MT3-MPP)), as well as BDNF and GAPDH. Expression was analyzed in nine different brain areas before, and at eight time points during the first 3 days after a strong neuroexcitatory stimulation, caused by one kainic acid injection. A temporo-spatial pattern of orderly transcriptional regulations emerges that strengthens the role of Nogo-signaling mechanisms for synaptic plasticity in synchrony with transcriptional increases of BDNF mRNA. For most Nogo-type signaling genes, the largest alterations of mRNA levels occur in the dentate gyrus, with marked alterations also in the CA1 region. Changes occurred somewhat later in several areas of the cerebral cortex. The detailed spatio-temporal pattern of mRNA presence and kainic acid-induced transcriptional response is gene-specific. We reveal that several different gene alterations combine to decrease (and later increase) Nogo-like signaling, as expected to allow structural plasticity responses. Other genes are altered in the opposite direction, suggesting that the system prepares in advance in order to rapidly restore balance. However, the fact that Lingo-1 shows a seemingly opposite, plasticity inhibiting response to kainic acid (strong increase of mRNA in the dentate gyrus), may instead suggest a plasticity-enhancing intracellular function of this presumed NgR1 co-receptor.

Restoring brain function after stroke - bridging the gap between animals and humans

Stroke is the leading cause of complex adult disability in the world. Recovery from stroke is often incomplete, which leaves many people dependent on others for their care. The improvement of long-term outcomes should, therefore, be a clinical and research priority. As a result of advances in our understanding of the biological mechanisms involved in recovery and repair after stroke, therapeutic opportunities to promote recovery through manipulation of poststroke plasticity have never been greater. This work has almost exclusively been carried out in preclinical animal models of stroke with little translation into human studies. The challenge ahead is to develop a mechanistic understanding of recovery from stroke in humans. Advances in neuroimaging techniques now enable us to reconcile behavioural accounts of recovery with molecular and cellular changes. Consequently, clinical trials can be designed in a stratified manner that takes into account when an intervention should be delivered and who is most likely to benefit. This approach is expected to lead to a substantial change in how restorative therapeutic strategies are delivered in patients after stroke.

Drugs in clinical development for the treatment of amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic Lateral Sclerosis (ALS) is a fatal motor neuron progressive disorder for which no treatment exists to date. However, there are other investigational drugs and therapies currently under clinical development may offer hope in the near future. Areas covered: We have reviewed all the ALS ongoing clinical trials (until November 2016) and collected in Clinicaltrials.gov or EudraCT. We have described them in a comprehensive way and have grouped them in the following sections: biomarkers, biological therapies, cell therapy, drug repurposing and new drugs. Expert opinion: Despite multiple obstacles that explain the absence of effective drugs for the treatment of ALS, joint efforts among patient's associations, public and private sectors have fueled innovative research in this field, resulting in several compounds that are in the late stages of clinical trials. Drug repositioning is also playing an important role, having achieved the approval of some orphan drug applications, in late phases of clinical development. Endaravone has been recently approved in Japan and is pending in USA.

Neuromuscular Disease in the Neurointensive Care Unit

Neuromuscular diseases are syndromic disorders that affect nerve, muscle, and/or neuromuscular junction. Knowledge about the management of these diseases is required for anesthesiologists, because these may frequently be encountered in the intensive care unit, operating room, and other settings. The challenges and advances in management for some of the neuromuscular diseases most commonly encountered in the operating room and neurointensive care unit are reviewed.

Nogo-A Antibodies for Progressive Multiple Sclerosis

Most of the current therapies, as well as many of the clinical trials, for multiple sclerosis (MS) target the inflammatory autoimmune processes, but less than 20% of all clinical trials investigate potential therapies for the chronic progressive disease stage of MS. The latter is responsible for the steadily increasing disability in many patients, and there is an urgent need for novel therapies that protect nervous system tissue and enhance axonal growth and/or remyelination. As outlined in this review, solid pre-clinical data suggest neutralization of the neurite outgrowth inhibitor Nogo-A as a potential new way to achieve both axonal and myelin repair. Several phase I clinical studies with anti-Nogo-A antibodies have been conducted in different disease paradigms including MS and spinal cord injury. Data from spinal cord injury and amyotrophic lateral sclerosis (ALS) trials accredit a good safety profile of high doses of anti-Nogo-A antibodies administered intravenously or intrathecally. An antibody against a Nogo receptor subunit, leucine rich repeat and immunoglobulin-like domain-containing protein 1 (LINGO-1), was recently shown to improve outcome in patients with acute optic neuritis in a phase II study. Nogo-A-suppressing antibodies could be novel drug candidates for the relapsing as well as the progressive MS disease stage. In this review, we summarize the available pre-clinical and clinical evidence on Nogo-A and elucidate the potential of Nogo-A-antibodies as a therapy for progressive MS.

Nogo receptor complex expression dynamics in the inflammatory foci of central nervous system experimental autoimmune demyelination

BACKGROUND

Nogo-A and its putative receptor NgR are considered to be among the inhibitors of axonal regeneration in the CNS. However, few studies so far have addressed the issue of local NgR complex multilateral localization within inflammation in an MS mouse model of autoimmune demyelination.

METHODS

Chronic experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice. Analyses were performed on acute (days 18-22) and chronic (day 50) time points and compared to controls. The temporal and spatial expression of the Nogo receptor complex (NgR and coreceptors) was studied at the spinal cord using epifluorescent and confocal microscopy or real-time PCR. Data are expressed as cells/mm2, as mean % ± SEM, or as arbitrary units of integrated density.

RESULTS

Animals developed a moderate to severe EAE without mortality, followed by a progressive, chronic clinical course. NgR complex spatial expression varied during the main time points of EAE. NgR with coreceptors LINGO-1 and TROY was increased in the spinal cord in the acute phase whereas LINGO-1 and p75 signal seemed to be dominant in the chronic phase, respectively. NgR was detected on gray matter NeuN+ neurons of the spinal cord, within the white matter inflammatory foci (14.2 ± 4.3 % NgR+ inflammatory cells), and found to be colocalized with GAP-43+ axonal growth cones while no β-TubIII+, SMI-32+, or APP+ axons were found as NgR+. Among the NgR+ inflammatory cells, 75.6 ± 9.0 % were microglial/macrophages (lectin+), 49.6 ± 14.2 % expressed CD68 (phagocytic ED1+ cells), and no cells were Mac-3+. Of these macrophages/monocytes, only Arginase-1+/NgR+ but not iNOS+/NgR+ were present in lesions both in acute and chronic phases.

CONCLUSIONS

Our data describe in detail the expression of the Nogo receptor complex within the autoimmune inflammatory foci and suggest a possible immune action for NgR apart from the established inhibitory one on axonal growth. Its expression by inflammatory macrophages/monocytes could signify a possible role of these cells on axonal guidance and clearance of the lesioned area during inflammatory demyelination.

Pathogenesis of amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) or motor neuron disease is a rapidly progressive neurodegenerative disorder. The primary involvement is of motor neurons in the brain, spinal cord and peripherally. There is secondary weakness of muscles and primary involvement of other brain regions, especially involving cognition.

SOURCES OF DATA

Peer-reviewed journal articles and reviews. PubMed.gov

AREAS OF AGREEMENT

The pathogenesis of ALS remains largely unknown. There are a wide range of potential mechanisms related to neurodegeneration. An increasing number of genetic factors are recognized.

AREAS OF CONTROVERSY

There remains controversy, or lack of knowledge, in explaining how cellular events manifest as the complex human disease. There is controversy as to how well cellular and animal models of disease relate to the human disease.

GROWING POINTS

Large-scale international collaborative genetic epidemiological studies are replacing local studies. Therapies related to pathogenesis remain elusive, with the greatest advances to date relating to provision of care (including multidisciplinary management) and supportive care (nutrition and respiratory support).

AREAS TIMELY FOR DEVELOPING RESEARCH

The identification of C9orf72 hexanucleotide repeats as the most frequent genetic background to ALS, and the association with frontotemporal dementia, gives the potential of a genetic background against which to study other risk factors, triggers and pathogenic mechanisms, and to develop potential therapies.

Amyotrophic Lateral Sclerosis, 2016: existing therapies and the ongoing search for neuroprotection

INTRODUCTION

Amyotrophic lateral sclerosis (ALS), one in a family of age-related neurodegenerative disorders, is marked by predominantly cryptogenic causes, partially elucidated pathophysiology, and elusive treatments. The challenges of ALS are illustrated by two decades of negative drug trials.

AREAS COVERED

In this article, we lay out the current understanding of disease genesis and physiology in relation to drug development in ALS, stressing important accomplishments and gaps in knowledge. We briefly consider clinical ALS, the ongoing search for biomarkers, and the latest in trial design, highlighting major recent and ongoing clinical trials; and we discuss, in a concluding section on future directions, the prion-protein hypothesis of neurodegeneration and what steps can be taken to end the drought that has characterized drug discovery in ALS.

EXPERT OPINION

Age-related neurodegenerative disorders are fast becoming major public health problems for the world's aging populations. Several agents offer promise in the near-term, but drug development is hampered by an interrelated cycle of obstacles surrounding etiological, physiological, and biomarkers discovery. It is time for the type of government-funded, public-supported offensive on neurodegenerative disease that has been effective in other fields.

Concise Review: Bridging the Gap: Novel Neuroregenerative and Neuroprotective Strategies in Spinal Cord Injury

Spinal cord injuries (SCIs) result in devastating lifelong disability for patients and their families. The initial mechanical trauma is followed by a damaging secondary injury cascade involving proapoptotic signaling, ischemia, and inflammatory cell infiltration. Ongoing cellular necrosis releases ATP, DNA, glutamate, and free radicals to create a cytotoxic postinjury milieu. Long-term regeneration of lost or injured networks is further impeded by cystic cavitation and the formation of an inhibitory glial-chondroitin sulfate proteoglycan scar. In this article, we discuss important neuroprotective interventions currently applied in clinical practice, including surgical decompression, blood pressure augmentation, and i.v. methylprednisolone. We then explore exciting translational therapies on the horizon, such as riluzole, minocycline, fibroblast growth factor, magnesium, and hypothermia. Finally, we summarize the key neuroregenerative strategies of the next decade, including glial scar degradation, Rho-ROCK inhibition, cell-based therapies, and novel bioengineered adjuncts. Throughout, we emphasize the need for combinatorial approaches to this multifactorial problem and discuss relevant studies at the forefront of translation. We conclude by providing our perspectives on the future direction of SCI research.

SIGNIFICANCE

Spinal cord injuries (SCIs) result in devastating, lifelong disability for patients and their families. This article discusses important neuroprotective interventions currently applied in clinical practice, including surgical decompression, blood pressure augmentation, and i.v. methylprednisolone. Translational therapies on the horizon are discussed, such as riluzole, minocycline, fibroblast growth factor, magnesium, and hypothermia. The key neuroregenerative strategies of the next decade are summarized, including glial scar degradation, Rho-ROCK inhibition, cell-based therapies, and novel bioengineered adjuncts. The need for combinatorial approaches to this multifactorial problem is emphasized, relevant studies at the forefront of translation are discussed, and perspectives on the future direction of SCI research are presented.

Promoting recovery from ischemic stroke

Over recent decades, experimental and clinical stroke studies have identified a number of neurorestorative treatments that stimulate neural plasticity and promote functional recovery. In contrast to the acute stroke treatments thrombolysis and endovascular thrombectomy, neurorestorative treatments are still effective when initiated days after stroke onset, which makes them applicable to virtually all stroke patients. In this article, selected physical, pharmacological and cell-based neurorestorative therapies are discussed, with special emphasis on interventions that have already been transferred from the laboratory to the clinical setting. We explain molecular and structural processes that promote neural plasticity, discuss potential limitations of neurorestorative treatments, and offer a speculative viewpoint on how neurorestorative treatments will evolve.

Non-canonical actions of Nogo-A and its receptors

Nogo-A is a myelin associated protein and one of the most potent neurite growth inhibitors in the central nervous system. Interference with Nogo-A signaling has thus been investigated as therapeutic target to promote functional recovery in CNS injuries. Still, the finding that Nogo-A presents a fairly ubiquitous expression in many types of neurons in different brain regions, in the eye and even in the inner ear suggests for further functions besides the neurite growth repression. Indeed, a growing number of studies identified a variety of functions including regulation of neuronal stem cells, modulation of microglial activity, inhibition of angiogenesis and interference with memory formation. Aim of the present commentary is to draw attention on these less well-known and sometimes controversial roles of Nogo-A. Furthermore, we are addressing the role of Nogo-A in neuropathological conditions such as ischemic stroke, schizophrenia and neurodegenerative diseases.

Use of biomarkers in ALS drug development and clinical trials

The past decade has seen a dramatic increase in the discovery of candidate biomarkers for ALS. These biomarkers typically can either differentiate ALS from control subjects or predict disease course (slow versus fast progression). At the same time, late-stage clinical trials for ALS have failed to generate improved drug treatments for ALS patients. Incorporation of biomarkers into the ALS drug development pipeline and the use of biologic and/or imaging biomarkers in early- and late-stage ALS clinical trials have been absent and only recently pursued in early-phase clinical trials. Further clinical research studies are needed to validate biomarkers for disease progression and develop biomarkers that can help determine that a drug has reached its target within the central nervous system. In this review we summarize recent progress in biomarkers across ALS model systems and patient population, and highlight continued research directions for biomarkers that stratify the patient population to enrich for patients that may best respond to a drug candidate, monitor disease progression and track drug responses in clinical trials. It is crucial that we further develop and validate ALS biomarkers and incorporate these biomarkers into the ALS drug development process. This article is part of a Special Issue entitled ALS complex pathogenesis.

Ozanezumab dose selection for amyotrophic lateral sclerosis by pharmacokinetic-pharmacodynamic modelling of immunohistochemistry data from patient muscle biopsies

Amyotrophic Lateral Sclerosis (ALS) is a rare and fatal neurodegenerative disease with a high unmet medical need. In this context, a potential therapy should be brought to patients in the most expeditious way and early exploration of pharmacology is highly beneficial. Ozanezumab, a humanised IgG monoclonal antibody against Nogo-A protein which is an inhibitor of neurite outgrowth, is currently under development for the treatment of ALS and has been recently assessed in 76 patients in a first-in-human study. Inadequate target engagement has been recognised as a major contributing reason for drug trial failures. In this work, we describe the development of a pharmacokinetic-pharmacodynamic (PKPD) model using immunohistochemistry (IHC) data of co-localization of ozanezumab with Nogo-A in skeletal muscle as a surrogate measure of target engagement. The rich plasma concentration data and the sparse IHC data after one or two intravenous doses of ozanezumab were modelled simultaneously using a non-linear mixed-effect approach. The final PKPD model was a two-compartment PK model combined with an effect compartment PD model that accounted for the delay in ozanezumab concentrations to reach the site of action which is skeletal muscle. Diagnostic plots showed a satisfactory fit of both PK and IHC data. The model was used as a simulation tool to design a dose regimen for sustained drug-target co-localization in a phase II study.

Treatment of rats with an anti-(+)-methamphetamine monoclonal antibody shortens the duration of action of repeated (+)-methamphetamine challenges over a one month period

This study assessed clinical scenarios of continuing monoclonal antibody (mAb) treatment for (+)-methamphetamine (METH) addiction, and the implications of missing or discontinuing this therapy. We hypothesized that chronic anti-METH mAb7F9 (METH KD=9 nM) treatment of rats could significantly decrease METH-induced behaviors; even with repeated METH challenges, use of METH doses in excess of mAb binding sites, and after discontinuing mAb treatment which results in a 10-fold reduction in mAb7F9 serum concentrations. Male Sprague Dawley rats (n=6/group) were treated with i.v. saline or a loading dose of mAb7F9 to achieve instant steady-state conditions followed by two weekly (141 mg/kg) doses ending on day 14. METH (0.56 mg/kg) was administered 4h and three days after each saline or mAb7F9 treatment, and on day 21. This produced locomotion and rearing behavior that lasted about 120 min in control rats. In mAb7F9 treated rats, METH-induced distance traveled was significantly reduced from 60 to 120 min (P<0.05) on days 0-21 and rearing was significantly reduced from 60 to 120 min on days 0-17. METH serum concentrations determined 5h after METH dosing was significantly increased in mAb7F9-treated rats after all METH challenges. On days 24 and 28 (the final day), the rats were administered a 3-fold higher METH dose (1.68 mg/kg). MAb7F9 treated rats showed a substantially earlier termination of the METH-induced locomotion on both days, even though the METH dose exceeded mAb7F9s binding capacity. METH brain concentrations determined 5h after METH on day 28 were also significantly decreased in mAb7F9-treated rats. In conclusion, over one month, mAb7F9 significantly and continuously bound METH and reduced METH-induced locomotor effects even after discontinuation of mAb treatment and challenge with higher METH doses.