Fasudil, a rho kinase inhibitor, limits motor neuron loss in experimental models of amyotrophic lateral sclerosis

SAFE-ROCK: A Phase I Trial of an Oral Application of the ROCK Inhibitor Fasudil to Assess Bioavailability, Safety, and Tolerability in Healthy Participants

BACKGROUND

The intravenous (IV) formulation of Rho-kinase (ROCK) inhibitor fasudil has been approved for the treatment of subarachnoid haemorrhage since 1995. Additionally, fasudil has shown promising preclinical results for various chronic diseases, including neurodegenerative diseases such as amyotrophic lateral sclerosis, Parkinson's disease, and dementia, in which long-term intravenous (IV) administration might not be suitable.

OBJECTIVE

The objective of this study was to assess the absolute bioavailability of oral, in comparison to IV, application of the approved formulation of fasudil (ERIL®) and to evaluate the safety and tolerability of the oral application of fasudil.

METHODS

This was a phase I, single-center, open-label, randomized, two period cross-over clinical trial in healthy women and men. By applying a cross-over design, each subject served as their own control. Two treatments were investigated, separated by a wash out phase of at least 3 days. Oral fasudil was administered once on day 1 to assess pharmacokinetics and three times on day 2, at an interval of 8 ± 1 h, to assess safety and gastrointestinal tolerability. For pharmacometrics of IV fasudil, it was administered once on day 1. Plasma profiles of fasudil and its active metabolite hydroxyfasudil after oral or IV administration were measured by liquid chromatography electrospray tandem mass spectrometry. Tolerability was assessed as proportion of subjects without significant drug intolerance, and safety was assessed by the proportion of subjects without clinical or laboratory treatment-associated serious adverse events. Gastrointestinal safety was assessed by applying the gastrointestinal symptom rating scale (GSRS).

RESULTS

Fourteen subjects aged 30-70 years were included in this trial. After oral administration, fasudil concentrations in blood were mostly very low [1.4 g/L; coefficient of variation (CV) 41.0%]. After IV application, the peak concentration was 100.6 µg/L (CV 74.2%); however, a high variance in peak concentrations were assessed for both treatments. The maximal concentrations of hydroxyfasudil in blood were similar after oral and IV treatment [111.6 µg/L (CV 24.1%) and 108.4 µg/L (CV 19.7%), respectively]. Exposure of hydroxyfasudil (assessed as AUC0-tz) differed between both treatments, with 449 µg × h/L after IV treatment and 309 µg × h/L after oral treatment. Therefore, the absolute bioavailability of hydroxyfasudil after the oral treatment was approximately 69% of the IV treatment. No serious adverse events (SAEs) occurred during this trial, and good tolerability of oral fasudil (90 mg/day) was documented.

CONCLUSIONS

Oral fasudil was generally well tolerated in the studied population, and no safety concerns were identified. However, systemic bioavailability of oral hydroxyfasudil corresponded to 69%, and dose adjustments need to considered. The results presented here lay grounds for future trials of fasudil in chronic diseases, which require an oral long-term application. This trial was registered with EudraCT (no. 2019-001805-26).

TwinF interface inhibitor FP802 stops loss of motor neurons and mitigates disease progression in a mouse model of ALS

Toxic signaling by extrasynaptic NMDA receptors (eNMDARs) is considered an important promoter of amyotrophic lateral sclerosis (ALS) disease progression. To exploit this therapeutically, we take advantage of TwinF interface (TI) inhibition, a pharmacological principle that, contrary to classical NMDAR pharmacology, allows selective elimination of eNMDAR-mediated toxicity via disruption of the NMDAR/TRPM4 death signaling complex while sparing the vital physiological functions of synaptic NMDARs. Post-disease onset treatment of the SOD1G93A ALS mouse model with FP802, a modified TI inhibitor with a safe pharmacology profile, stops the progressive loss of motor neurons in the spinal cord, resulting in a reduction in the serum biomarker neurofilament light chain, improved motor performance, and an extension of life expectancy. FP802 also effectively blocks NMDA-induced death of neurons in ALS patient-derived forebrain organoids. These results establish eNMDAR toxicity as a key player in ALS pathogenesis. TI inhibitors may provide an effective treatment option for ALS patients.

Protocol for a randomized, placebo-controlled, double-blind phase IIa study of the safety, tolerability, and symptomatic efficacy of the ROCK-inhibitor Fasudil in patients with Parkinson's disease (ROCK-PD)

Background

The Rho-kinase (ROCK) inhibitor Fasudil has shown symptomatic and disease-modifying effects in Parkinson's disease (PD) models in vitro and in vivo. In Japan, Fasudil has been approved for the treatment of subarachnoid haemorrhage since 1995 and shows a favourable safety profile.

Objectives/design

To investigate the safety, tolerability, and symptomatic efficacy of ROCK-inhibitor Fasudil in comparison to placebo in a randomized, national, multicenter, double-blind phase IIa study in patients with PD.

Methods/analysis

We plan to include 75 patients with at least 'probable' PD (MDS criteria), Hoehn and Yahr stages 1-3, and age 30-80 years in 13 German study sites. Patients must be non-fluctuating and their response to PD medication must have been stable for 6 weeks. Patients will be randomly allocated to treatment with the oral investigational medicinal product (IMP) containing either Fasudil in two dosages, or placebo, for a total of 22 days. As primary analysis, non-inferiority of low/high dose of Fasudil on the combined endpoint consisting of occurrence of intolerance and/or treatment-related serious adverse events (SAEs) over 22 days will be assessed in a sequential order, starting with the lower dose. Secondary endpoints will include tolerability alone over 22 days and occurrence of treatment-related SAEs (SARs) over 22 and 50 days and will be compared on group level. Additional secondary endpoints include efficacy on motor and non-motor symptoms, measured on established scales, and will be assessed at several timepoints. Biomaterial will be collected to determine pharmacokinetics of Fasudil and its active metabolite, and to evaluate biomarkers of neurodegeneration.

Ethics/registration/discussion

After positive evaluation by the competent authority and the ethics committee, patient recruitment started in the 3rd quarter of 2023. ROCK-PD is registered with Eudra-CT (2021-003879-34) and clinicaltrials.gov (NCT05931575). Results of this trial can pave way for conducting extended-duration studies assessing both symptomatic efficacy and disease-modifying properties of Fasudil.

Hydroxyfasudil regulates immune balance and suppresses inflammatory responses in the treatment of experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is a central nervous system (CNS) disease with complicated etiology. Multifocal demyelination and invasion of inflammatory cells are its primary pathological features. Fasudil has been confirmed to improve experimental autoimmune encephalomyelitis (EAE), an animal model of MS. However, Fasudil is accompanied by several shortcomings in the clinical practice. Hydroxyfasudil is a metabolite of Fasudil in the body with better pharmaceutical properties. Therefore, we attempted to study the influence of Hydroxyfasudil upon EAE mice. The results demonstrated that Hydroxyfasudil relieved the symptoms of EAE and the associated pathological damage, reduced the adhesion molecules and chemokines, decreased the invasion of peripheral immune cells. Simultaneously, Hydroxyfasudil modified the rebalance of peripheral T cells. Moreover, Hydroxyfasudil shifted the M1 phenotype to M2 polarization, inhibited inflammatory signaling cascades as well as inflammatory factors, and promoted anti-inflammatory factors in the CNS. In the end, mice in the Hydroxyfasudil group expressed more tight junction proteins, indirectly indicating that the blood-brain barrier (BBB) was protected. Our results indicate that Hydroxyfasudil may be a prospective treatment for MS.

Microglia in neurodegenerative diseases: mechanism and potential therapeutic targets

Microglia activation is observed in various neurodegenerative diseases. Recent advances in single-cell technologies have revealed that these reactive microglia were with high spatial and temporal heterogeneity. Some identified microglia in specific states correlate with pathological hallmarks and are associated with specific functions. Microglia both exert protective function by phagocytosing and clearing pathological protein aggregates and play detrimental roles due to excessive uptake of protein aggregates, which would lead to microglial phagocytic ability impairment, neuroinflammation, and eventually neurodegeneration. In addition, peripheral immune cells infiltration shapes microglia into a pro-inflammatory phenotype and accelerates disease progression. Microglia also act as a mobile vehicle to propagate protein aggregates. Extracellular vesicles released from microglia and autophagy impairment in microglia all contribute to pathological progression and neurodegeneration. Thus, enhancing microglial phagocytosis, reducing microglial-mediated neuroinflammation, inhibiting microglial exosome synthesis and secretion, and promoting microglial conversion into a protective phenotype are considered to be promising strategies for the therapy of neurodegenerative diseases. Here we comprehensively review the biology of microglia and the roles of microglia in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, multiple system atrophy, amyotrophic lateral sclerosis, frontotemporal dementia, progressive supranuclear palsy, corticobasal degeneration, dementia with Lewy bodies and Huntington's disease. We also summarize the possible microglia-targeted interventions and treatments against neurodegenerative diseases with preclinical and clinical evidence in cell experiments, animal studies, and clinical trials.

Emerging clinical investigational drugs for the treatment of amyotrophic lateral sclerosis

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder caused by motoneuron death with a median survival time of 3-5 years since disease onset. There are no effective treatments to date. However, a variety of innovative investigational drugs and biological-based therapies are under clinical development.

AREAS COVERED

This review provides an overview of the clinical investigational small molecules as well as a brief summary of the biological-based therapies that are currently undergoing clinical trials for the treatment of ALS. All the data were obtained from ClinicalTrials.gov (registered through November 1).

EXPERT OPINION

Drug discovery for ALS is an active and evolving field, where many investigational clinical drugs are in different trials. There are several mechanisms of action supporting all these new therapies, although proteostasis is gaining stage. Probably, small orally bioavailable molecules able to recover functional TDP-43 homeostasis may have solid chances to modify ALS progression.

Key role of Rho GTPases in motor disorders associated with neurodevelopmental pathologies

Growing evidence suggests that Rho GTPases and molecules involved in their signaling pathways play a major role in the development of the central nervous system (CNS). Whole exome sequencing (WES) and de novo examination of mutations, including SNP (Single Nucleotide Polymorphism) in genes coding for the molecules of their signaling cascade, has allowed the recent discovery of dominant autosomic mutations and duplication or deletion of candidates in the field of neurodevelopmental diseases (NDD). Epidemiological studies show that the co-occurrence of several of these neurological pathologies may indeed be the rule. The regulators of Rho GTPases have often been considered for cognitive diseases such as intellectual disability (ID) and autism. But, in a remarkable way, mild to severe motor symptoms are now reported in autism and other cognitive NDD. Although a more abundant litterature reports the involvement of Rho GTPases and signaling partners in cognitive development, molecular investigations on their roles in central nervous system (CNS) development or degenerative CNS pathologies also reveal their role in embryonic and perinatal motor wiring through axon guidance and later in synaptic plasticity. Thus, Rho family small GTPases have been revealed to play a key role in brain functions including learning and memory but their precise role in motor development and associated symptoms in NDD has been poorly scoped so far, despite increasing clinical data highlighting the links between cognition and motor development. Indeed, early impairements in fine or gross motor performance is often an associated feature of NDDs, which then impact social communication, cognition, emotion, and behavior. We review here recent insights derived from clinical developmental neurobiology in the field of Rho GTPases and NDD (autism spectrum related disorder (ASD), ID, schizophrenia, hypotonia, spastic paraplegia, bipolar disorder and dyslexia), with a specific focus on genetic alterations affecting Rho GTPases that are involved in motor circuit development.

Dysregulation of miR-193a serves as a potential contributor to MS pathogenesis via affecting RhoA and Rock1

BACKGROUND

Multiple sclerosis (MS) is one of the most common neurological diseases that cause chronic inflammation of the central nervous system and demyelination of the myelin sheath. At present, microRNAs (miRNAs) are considered not only a diagnostic and prognostic indicator of diseases but also a new goal in gene therapy. This study aims to find a simple, non-invasive, valuable biomarker for early detection and potential treatment of MS.

METHODS

In the present study, 30 patients with MS were included. The qRT-PCR method was performed to evaluate the expression level of miR-193a, RhoA, and ROCK1. Besides, western blotting was performed to determine the expression level of RhoA and ROCK1 at protein levels. Moreover, we aimed to clarify the possible correlation between miR-193a-5p and its-regulated target genes so that miR-193a-5p mimic was transfected into MS-derived cultured PBMSs, and the expression level of RhoA and ROCK1 were then evaluated by qRT-PCR and Western blotting. In the final step, the correlation between miR-193a-5p and clinicopathological features of patients was investigated.

RESULTS

Results showed that miR-193a was decreased while RhoA and ROCK1 were up-regulated in PBMCs obtained from patients with MS compared to the control group. It was also revealed that miR-193a transfection reduced RhoA and ROCK1 expression at mRNA and protein levels. The results from the Chi-square analysis showed that down-regulation of miR-193a was associated with increased CRP level, CSF IgG positivity, and MSSS (Multiple Sclerosis Severity Score), suggesting miR-193a is a potential diagnostic and prognostic indicator.

CONCLUSION

We implied that miR-193a could modulate RhoA and ROCK 1 expression in MS patients, in which its down-regulation leads to increased expression of RhoA and ROCK1 and poor prognosis of patients with MS. Therefore, miR-193a and its associated targets could serve potential prognostic, diagnostic, and therapeutic efficacy in MS patients.

Cytoskeleton saga: Its regulation in normal physiology and modulation in neurodegenerative disorders

Cells are fundamental units of life. To ensure the maintenance of homeostasis, integrity of structural and functional counterparts is needed to be essentially balanced. The cytoskeleton plays a vital role in regulating the cellular morphology, signalling and other factors involved in pathological conditions. Microtubules, actin (microfilaments), intermediate filaments (IF) and their interactions are required for these activities. Various proteins associated with these components are primary requirements for directing their functions. Disruption of this organization due to faulty genetics, oxidative stress or impaired transport mechanisms are the major causes of dysregulated signalling cascades leading to various pathological conditions like Alzheimer's (AD), Parkinson's (PD), Huntington's disease (HD) or amyotrophic lateral sclerosis (ALS), hereditary spastic paraplegia (HSP) or any traumatic injury like spinal cord injury (SCI). Novel or conventional therapeutic approaches may be specific or non-specific, targeting either three basic components of the cytoskeleton or various cascades that serve as a cue to numerous pathways like ROCK signalling or the GSK-3β pathway. An enormous number of drugs have been redirected for modulating the cytoskeletal dynamics and thereby may pave the way for inhibiting the progression of these diseases and their complications.

RhoA Signaling in Neurodegenerative Diseases

Ras homolog gene family member A (RhoA) is a small GTPase of the Rho family involved in regulating multiple signal transduction pathways that influence a diverse range of cellular functions. RhoA and many of its downstream effector proteins are highly expressed in the nervous system, implying an important role for RhoA signaling in neurons and glial cells. Indeed, emerging evidence points toward a role of aberrant RhoA signaling in neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, and amyotrophic lateral sclerosis. In this review, we summarize the current knowledge of RhoA regulation and downstream cellular functions with an emphasis on the role of RhoA signaling in neurodegenerative diseases and the therapeutic potential of RhoA inhibition in neurodegeneration.

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.

Modeling axonal regeneration by changing cytoskeletal dynamics in stem cell-derived motor nerve organoids

Oxidative stress triggers axon degeneration and cell death, leading to the development of neurodegenerative diseases. Spinal motor nerves project very long axons, increasing the burden on axonal transport and metabolism. As such, spinal motor nerves are expected to be susceptible to oxidative stress, but model systems for visualizing and investigating acutely degenerating motor axons are limited. In this study, we establish motor nerve organoids from human pluripotent stem cells (hPSCs) with properties similar to those of neuromesodermal progenitors (NMPs), a population of progenitor cells that comprise the caudal spinal cord. Three-dimensional differentiation of organoids efficiently gave rise to mature motor neurons within 18 days. Adherent organoids showed robust axon fascicles and active growth cones under normal conditions. In addition, more homogenous and efficient generation of motor neurons were achieved when organoids were dissociated into individual cells. Hydrogen peroxide-induced oxidative stress resulted in a broad range of signs of axon degeneration including the disappearance of growth cones and neurites, axon retraction, axon fragmentation and bleb formation, and apoptotic cell death, whose severity can be reliably quantifiable in our culture system. Remarkably, cytoskeletal drugs modulating actin or microtubule turnover differentially facilitated axon dynamics and increased axon regenerative potential. Taken together, our motor nerve organoid model could be potentially useful for drug screens evaluating the rearrangement of cytoskeletons in regenerating motor axons.

Microglia in motor neuron disease: Signaling evidence from last 10 years

Motor neuron disease (MND), including amyotrophic lateral sclerosis, spinal muscular atrophy and others, involved the upper or lower motor neurons selective loss, is characterized by neurodegeneration and neuroinflammation, in conjunction with microglia. We summarized that pathways and key mediators are associated with microglia, such as fractalkine signaling, purinergic signaling, NF-κB signaling, p38 MAPK signaling, TREM2-APOE signaling, ROCK signaling, C1q signaling, and Ion channel, which are involved in the activation, proliferation, and inflammation of microglia. This review aims to identify the microglia-related molecular target and explore potential treatment strategies for MND based on that target.

Histopathological changes of the spinal cord and motor neuron dynamics in SOD1 Tg mice

We analyzed the histopathological changes and the number of motor neurons (MNs) in the lumbar spinal cord of Cu/Zn superoxide dismutase transgenic (SOD1^G93ATg) mice, which are frequently used as a disease model of amyotrophic lateral sclerosis (ALS). In SOD1^G93ATg mice, hyaline inclusions and foamy vacuoles in the neuronal cell body were observed at 7 weeks of age before neurologic symptoms, and large vacuoles, spheroid formation, and nerve cell aggregation became prominent after 13 weeks of age. The number of healthy MNs was 28.7 to 37.1 cells/animal in wild-type mice and 9.3 to 13.6 cells/animal in transgenic (Tg) mice. Furthermore, the number of MNs, including degenerative neurons, in Tg mice was 27.3–36.1 cells/animal at 18 weeks of age and 17.8–19.6 cells/animal at 21 weeks of age. The present results provide useful information for the development of drugs in ALS treatment.

Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses

Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.

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.

Repurposing old molecules for new indications: Defining pillars of success from lessons in the past

Drug repurposing or studying existing drugs for potential therapeutic utility in newer indications has been identified as an attractive option for treating a number of diseases. Various strategies of drug repurposing include serendipitous observation of drug's unexpected effects, directing the failed investigational drugs to new indications and currently adopted systematic approach to identify, screen and develop existing drug molecules for new off-label indications. Drug repurposing is able to constructively overcome the bottleneck restraints encountered during traditional de novo drug development process in grounds of timelines, cost and resources. However, success rates of drug repurposing programs are not very impressive. Through a meticulous examination of some failed repurposing attempts we aimed to identify key factors leading to high attrition rate in such studies. Based on the fundamental elements of knowledge and evaluation, we have defined four pillars toward improving success rate in drug repurposing programs viz. sound knowledge of the repurposed drug's pharmacological characteristics (pillar 1: drug pharmacology); drug formulation considerations in new indication (pillar 2: drug formulation); evaluation in representative biological assays with translational potential (pillar 3: evaluation in biological assays); and robust clinical trial methodologies including biomarker driven approach to provide conclusive evidence of repurposed drug's efficacy in new indication (pillar 4: clinical evaluation). In addition to the pharmacological challenges, certain regulatory concerns, including lack of clear guidelines for evaluation and market exclusivity pose hurdles in the application of drug repurposing, which may however be overcome to a great extent by adopting some strategies as discussed in this review.

Role of EphA4 in Mediating Motor Neuron Death in MND

Motor neuron disease (MND) comprises a group of fatal neurodegenerative diseases with no effective cure. As progressive motor neuron cell death is one of pathological characteristics of MND, molecules which protect these cells are attractive therapeutic targets. Accumulating evidence indicates that EphA4 activation is involved in MND pathogenesis, and inhibition of EphA4 improves functional outcomes. However, the underlying mechanism of EphA4’s function in MND is unclear. In this review, we first present results to demonstrate that EphA4 signalling acts directly on motor neurons to cause cell death. We then review the three most likely mechanisms underlying this effect.

Emerging targets in drug discovery against neurodegenerative diseases: Control of synapsis disfunction by the RhoA/ROCK pathway

Synaptic spine morphology is controlled by the activity of Rac1, Cdc42 and RhoA, which need to be finely balanced, and in particular RhoA/ROCK prevents the formation of new protrusions by stabilizing actin formation. These processes are crucial to the maturation process, slowing the de novo generation of new spines. The RhoA/ROCK also influences plasticity processes, and selective modulation by ROCK1 of MLC-dependent actin dynamics leads to neurite retraction, but not to spine retraction. ROCK1 is also responsible for the reduction of the readily releasable pool of synaptic vesicles. These and other evidences suggest that ROCK1 is the main isoform acting on the presynaptic neuron. On the other hand, ROCK2 seems to have broad effects on LIMK/cofilin-dependent plasticity processes such as cofilin-dependent PSD changes. The RhoA/ROCK pathway is an important factor in several different brain-related pathologies via both downstream and upstream pathways. In the aggregate, these evidences show that the RhoA/ROCK pathway has a central role in the etiopathogenesis of a large group of CNS diseases, which underscores the importance of the pharmacological modulation of RhoA/ROCK as an important pathway to drug discovery in the neurodegenerative disease area. This article aims at providing the first review of the role of compounds acting on the RhoA/ROCK pathway in the control of synaptic disfunction.

The Regulatory Role of Reticulons in Neurodegeneration: Insights Underpinning Therapeutic Potential for Neurodegenerative Diseases

In the last few decades, cytoplasmic organellar dysfunction, such as that of the endoplasmic reticulum (ER), has created a new area of research interest towards the development of serious health maladies including neurodegenerative diseases. In this context, the extensively dispersed family of ER-localized proteins, i.e. reticulons (RTNs), is gaining interest because of its regulative control over neural regeneration. As most neurodegenerative diseases are pathologically manifested with the accretion of misfolded proteins with subsequent induction of ER stress, the regulatory role of RTNs in neural dysfunction cannot be ignored. With the limited information available in the literature, delineation of the functional connection between rising consequences of neurodegenerative diseases and RTNs need to be elucidated. In this review, we provide a broad overview on the recently revealed regulatory roles of reticulons in the pathophysiology of several health maladies, with special emphasis on neurodegeneration. Additionally, we have also recapitulated the decisive role of RTN4 in neurite regeneration and highlighted how neurodegeneration and proteinopathies are mechanistically linked with each other through specific RTN paralogues. With the recent findings advocating zebrafish Rtn4b (a mammalian Nogo-A homologue) downregulation following central nervous system (CNS) lesion, RTNs provides new insight into the CNS regeneration. However, there are controversies with respect to the role of Rtn4b in zebrafish CNS regeneration. Given these controversies, the connection between the unique regenerative capabilities of zebrafish CNS by distinct compensatory mechanisms and Rtn4b signalling pathway could shed light on the development of new therapeutic strategies against serious neurodegenerative diseases.

Amyotrophic Lateral Sclerosis: Molecular Mechanisms, Biomarkers, and Therapeutic Strategies

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with the progressive loss of motor neurons, leading to a fatal paralysis. According to whether there is a family history of ALS, ALS can be roughly divided into two types: familial and sporadic. Despite decades of research, the pathogenesis of ALS is still unelucidated. To this end, we review the recent progress of ALS pathogenesis, biomarkers, and treatment strategies, mainly discuss the roles of immune disorders, redox imbalance, autophagy dysfunction, and disordered iron homeostasis in the pathogenesis of ALS, and introduce the effects of RNA binding proteins, ALS-related genes, and non-coding RNA as biomarkers on ALS. In addition, we also mention other ALS biomarkers such as serum uric acid (UA), cardiolipin (CL), chitotriosidase (CHIT1), and neurofilament light chain (NFL). Finally, we discuss the drug therapy, gene therapy, immunotherapy, and stem cell-exosomal therapy for ALS, attempting to find new therapeutic targets and strategies. A challenge is to study the various mechanisms of ALS as a syndrome. Biomarkers that have been widely explored are indispensable for the diagnosis, treatment, and prevention of ALS. Moreover, the development of new genes and targets is an urgent task in this field.

Rho-associated kinases contribute to the regulation of tau phosphorylation and amyloid metabolism during neuronal plasticity

BACKGROUND

Neural plasticity under physiological condition develops together with normal tau phosphorylation and amyloid precursor protein (APP) processing. Since restoration of PI3-kinase signaling has therapeutic potential in Alzheimer's disease, we investigated plasticity-related changes in tau and APP metabolism by the selective Rho-kinase inhibitor fasudil.

METHODS

Field potentials composed of a field excitatory post-synaptic potential (fEPSP) and a population spike (PS) were recorded from a granule cell layer of the dentate gyrus. Plasticity of synaptic strength and neuronal function was induced by strong tetanic stimulation (HFS) and low-frequency stimulation (LFS) patterns. Infusions of saline or fasudil were given for 1 h starting from the application of the induction protocols. Total and phosphorylated tau levels and soluble APPα levels were measured in the hippocampus, which was removed after at least 1 h post-induction period.

RESULTS

Fasudil infusion resulted in attenuation of fEPSP slope and PS amplitude in response to both HFS and LFS. Fasudil reduced total tau and phosphorylated tau at residue Thr¹⁸¹ in the HFS-stimulated hippocampus, while Thr²³¹ phosphorylation was reduced by fasudil treatment in the LFS-stimulated hippocampus. Ser⁴¹⁶ phosphorylation was increased by fasudil treatment in both HFS- and LFS-stimulated hippocampus. Fasudil significantly increased soluble APPα in LFS-stimulated hippocampus, but not in HFS-stimulated hippocampus.

CONCLUSION

In light of our findings, we suggest that increased activity of Rho kinase could trigger a mechanism that goes awry during synaptic plasticity which is reversed by a Rho-kinase inhibitor. Thus, Rho-kinase inhibition might be a therapeutic target in cognitive disorders.

Pharmacological Modulators of Small GTPases of Rho Family in Neurodegenerative Diseases

Classical Rho GTPases, including RhoA, Rac1, and Cdc42, are members of the Ras small GTPase superfamily and play essential roles in a variety of cellular functions. Rho GTPase signaling can be turned on and off by specific GEFs and GAPs, respectively. These features empower Rho GTPases and their upstream and downstream modulators as targets for scientific research and therapeutic intervention. Specifically, significant therapeutic potential exists for targeting Rho GTPases in neurodegenerative diseases due to their widespread cellular activity and alterations in neural tissues. This study will explore the roles of Rho GTPases in neurodegenerative diseases with focus on the applications of pharmacological modulators in recent discoveries. There have been exciting developments of small molecules, nonsteroidal anti-inflammatory drugs (NSAIDs), and natural products and toxins for each classical Rho GTPase category. A brief overview of each category followed by examples in their applications will be provided. The literature on their roles in various diseases [e.g., Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), Frontotemporal dementia (FTD), and Multiple sclerosis (MS)] highlights the unique and broad implications targeting Rho GTPases for potential therapeutic intervention. Clearly, there is increasing knowledge of therapeutic promise from the discovery of pharmacological modulators of Rho GTPases for managing and treating these conditions. The progress is also accompanied by the recognition of complex Rho GTPase modulation where targeting its signaling can improve some aspects of pathogenesis while exacerbating others in the same disease model. Future directions should emphasize the importance of elucidating how different Rho GTPases work in concert and how they produce such widespread yet different cellular responses during neurodegenerative disease progression.

The Cellular Prion Protein-ROCK Connection: Contribution to Neuronal Homeostasis and Neurodegenerative Diseases

Amyloid-based neurodegenerative diseases such as prion, Alzheimer's, and Parkinson's diseases have distinct etiologies and clinical manifestations, but they share common pathological events. These diseases are caused by abnormally folded proteins (pathogenic prions PrP^Sc in prion diseases, β-amyloids/Aβ and Tau in Alzheimer's disease, α-synuclein in Parkinson's disease) that display β-sheet-enriched structures, propagate and accumulate in the nervous central system, and trigger neuronal death. In prion diseases, PrP^Sc-induced corruption of the physiological functions exerted by normal cellular prion proteins (PrP^C) present at the cell surface of neurons is at the root of neuronal death. For a decade, PrP^C emerges as a common cell surface receptor for other amyloids such as Aβ and α-synuclein, which relays, at least in part, their toxicity. In lipid-rafts of the plasma membrane, PrP^C exerts a signaling function and controls a set of effectors involved in neuronal homeostasis, among which are the RhoA-associated coiled-coil containing kinases (ROCKs). Here we review (i) how PrP^C controls ROCKs, (ii) how PrP^C-ROCK coupling contributes to neuronal homeostasis, and (iii) how the deregulation of the PrP^C-ROCK connection in amyloid-based neurodegenerative diseases triggers a loss of neuronal polarity, affects neurotransmitter-associated functions, contributes to the endoplasmic reticulum stress cascade, renders diseased neurons highly sensitive to neuroinflammation, and amplifies the production of neurotoxic amyloids.

Rho-kinase inhibition by fasudil modulates pre-synaptic vesicle dynamics

The Rho kinase (ROCK) signaling pathway is an attractive therapeutic target in neurodegeneration since it has been linked to the prevention of neuronal death and neurite regeneration. The isoquinoline derivative fasudil is a potent ROCK inhibitor, which is already approved for chronic clinical treatment in humans. However, the effects of chronic fasudil treatments on neuronal function are still unknown. We analyzed here chronic fasudil treatment in primary rat hippocampal cultures. Neurons were stimulated with 20 Hz field stimulation and we investigated pre-synaptic mechanisms and parameters regulating synaptic transmission after fasudil treatment by super resolution stimulated emission depletion (STED) microscopy, live-cell fluorescence imaging, and western blotting. Fasudil did not affect basic synaptic function or the amount of several synaptic proteins, but it altered the chronic dynamics of the synaptic vesicles. Fasudil reduced the proportion of the actively recycling vesicles, and shortened the vesicle lifetime, resulting overall in a reduction of the synaptic response upon stimulation. We conclude that fasudil does not alter synaptic structure, accelerates vesicle turnover, and decreases the number of released vesicles. This broadens the known spectrum of effects of this drug, and suggests new potential clinical uses.

Environmental enrichment combined with fasudil promotes motor function recovery and axonal regeneration after stroke

Fasudil, a Rho-associated protein kinase (ROCK) inhibitor, has a protective effect on the central nervous system. In addition, environmental enrichment is a promising technique for inducing the recovery of motor impairments in ischemic stroke models. The present study aimed to explore whether environmental enrichment combined with fasudil can facilitate motor function recovery and induce cortical axonal regeneration after stroke. First, a mouse model of ischemic cerebral stroke was established by photochemical embolization of the left sensorimotor cortex. Fasudil solution (10 mg/kg per day) was injected intraperitoneally for 21 days after the photothrombotic stroke. An environmental enrichment intervention was performed on days 7–21 after the photothrombotic stroke. The results revealed that environmental enrichment combined with fasudil improved motor function, increased growth-associated protein 43 expression in the infarcted cerebral cortex, promoted axonal regeneration on the contralateral side, and downregulated ROCK, p-LIM domain kinase (LIMK)1, and p-cofilin expression. The combined intervention was superior to monotherapy. These findings suggest that environmental enrichment combined with fasudil treatment promotes motor recovery after stroke, at least partly by stimulating axonal regeneration. The underlying mechanism might involve ROCK/LIMK1/cofilin pathway regulation. This study was approved by the Institutional Animal Care and Use Committee of Fudan University, China (approval No. 20160858A232) on February 24, 2016.

Recent advances in understanding amyotrophic lateral sclerosis and emerging therapies

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that is characterized by degeneration of both upper and lower motor neurons and subsequent progressive loss of muscle function. Within the last decade, significant progress has been made in the understanding of the etiology and pathobiology of the disease; however, treatment options remain limited and only two drugs, which exert a modest effect on survival, are approved for ALS treatment in the US. Therefore, the search for effective ALS therapies continues, and over 60 clinical trials are in progress for patients with ALS and other therapeutics are at the pre-clinical stage of development. Recent advances in understanding the genetics, pathology, and molecular mechanisms of ALS have led to the identification of novel targets and strategies that are being used in emerging ALS therapeutic interventions. Here, we review the current status and mechanisms of action of a selection of emerging ALS therapies in pre-clinical or early clinical development, including gene therapy, immunotherapy, and strategies that target neuroinflammation, phase separation, and protein clearance.

Fasudil attenuates glial cell-mediated neuroinflammation via ERK1/2 and AKT signaling pathways after optic nerve crush

To investigate the functional role of fasudil in optic nerve crush (ONC), and further explore its possible molecular mechanism. After ONC injury, the rats were injected intraperitoneally either with fasudil or normal saline once a day until euthanized. RGCs survival was assessed by retrograde labeling with FluoroGold. Retinal glial cells activation and population changes (GFAP, iba-1) were measured by immunofluorescence. The expressions of cleaved caspase 3 and 9, p-ERK1/2 and p-AKT were detected by western blot. The levels of the pro-inflammatory cytokines were determined using real-time polymerase chain reaction. Fasudil treatment inhibited RGCs apoptosis and reduced RGCs loss demonstrated by the decreased apoptosis-associated proteins expression and the increased fluorogold labeling of RGCs after ONC, respectively. In addition, the ONC + fasudil group compared had a significantly lower expression of GFAP and iba1 compared with the ONC group. The levels of pro-inflammatory cytokines were significantly reduced in the ONC + fasudil group than in the ONC group. Furthermore, the phosphorylation levels of ERK1/2 and AKT (p-ERK1/2 and p-AKT) were obviously elevated by the fasudil treatment. Our study demonstrated that fasudil attenuated glial cell-mediated neuroinflammation by up-regulating the ERK1/2 and AKT signaling pathways in rats ONC models. We conclude that fasudil may be a novel treatment for traumatic optic neuropathy.

Clinically Precedented Protein Kinases: Rationale for Their Use in Neurodegenerative Disease

Kinases are an intensively studied drug target class in current pharmacological research as evidenced by the large number of kinase inhibitors being assessed in clinical trials. Kinase-targeted therapies have potential for treatment of a broad array of indications including central nervous system (CNS) disorders. In addition to the many variables which contribute to identification of a successful therapeutic molecule, drug discovery for CNS-related disorders also requires significant consideration of access to the target organ and specifically crossing the blood-brain barrier (BBB). To date, only a small number of kinase inhibitors have been reported that are specifically designed to be BBB permeable, which nonetheless demonstrates the potential for success. This review considers the potential for kinase inhibitors in the context of unmet medical need for neurodegenerative disease. A subset of kinases that have been the focus of clinical investigations over a 10-year period have been identified and discussed individually. For each kinase target, the data underpinning the validity of each in the context of neurodegenerative disease is critically evaluated. Selected molecules for each kinase are identified with information on modality, binding site and CNS penetrance, if known. Current clinical development in neurodegenerative disease are summarized. Collectively, the review indicates that kinase targets with sufficient rationale warrant careful design approaches with an emphasis on improving brain penetrance and selectivity.

Protein kinase inhibitors for amyotrophic lateral sclerosis therapy

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that causes the progressive loss of motoneurons and, unfortunately, there is no effective treatment for this disease. Interconnecting multiple pathological mechanisms are involved in the neuropathology of this disease, including abnormal aggregation of proteins, neuroinflammation and dysregulation of the ubiquitin proteasome system. Such complex mechanisms, together with the lack of reliable animal models of the disease have hampered the development of drugs for this disease. Protein kinases, a key pharmacological target in several diseases, have been linked to ALS as they play a central role in the pathology of many diseases. Therefore several inhibitors are being currently trailed for clinical proof of concept in ALS patients. In this review, we examine the recent literature on protein kinase inhibitors currently in pharmaceutical development for this diseaseas future therapy for AS together with their involvement in the pathobiology of ALS. LINKED ARTICLES: This article is part of a themed issue on Neurochemistry in Japan. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.6/issuetoc.

Involvement of orexinergic system in psychiatric and neurodegenerative disorders: A scoping review

Orexin is a neuropeptide secreted from lateral hypothalamus and pre-frontal cortex concerned in the wakefulness and excitement. This study aimed to review the possible neurobiological effect of orexin. A diversity of search strategies was adopted and assumed which included electronic database searches of Medline and PubMed using MeSH terms, keywords, and title words during the search. Orexin plays a vital role in activation of learning, memory acquisition, and consolidation through activation of monoaminergic system, which affect cognitive flexibility and cognitive function. Orexin stimulates adrenocorticotropin and corticosteroid secretions via activation of central corticotropin-releasing hormone. Cerebrospinal fluid (CSF) and serum orexin serum levels are reduced in depression, schizophrenia, and narcolepsy. However, high orexin serum levels are revealed in drug addictions. Regarding neurodegenerative brain diseases, CSF and serum orexin serum levels are reduced Parkinson disease, Alzheimer dementia, Huntington's disease, amyotrphic lateral sclerosis, and multiple sclerosis. Orexin antagonist leads to significant reduction of sympathetic over-activity during withdrawal syndrome. As well, orexin antagonist improves sleep pattern. Orexinergic system is involved in the different psychiatric and neurological disorders; therefore, targeting of this system could be possible novel pathway in the management of these disorders. In addition, measurement of CSF and serum orexin levels might predict the relapse and withdrawal of addict patients.

Emerging Drugs for the Treatment of Amyotrophic Lateral Sclerosis: A Focus on Recent Phase 2 Trials

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease involving both upper and lower motor neurons and resulting in increasing disability and death 3-5 years after onset of symptoms. Over 40 large clinical trials for ALS have been negative, except for Riluzole that offers a modest survival benefit, and Edaravone that modestly reduces disease progression in patients with specific characteristics. Thus, the discovery of efficient disease modifying therapy is an urgent need.

AREAS COVERED

Although the cause of ALS remains unclear, many studies have demonstrated that neuroinflammation, proteinopathies, glutamate-induced excitotoxicity, microglial activation, oxidative stress, and mitochondrial dysfunction may play a key role in the pathogenesis. This review highlights recent discoveries relating to these diverse mechanisms and their implications for the development of therapy. Ongoing phase 2 clinical trials aimed to interfere with these pathophysiological mechanisms are discussed.

EXPERT OPINION

This review describes the challenges that the discovery of an efficient drug therapy faces and how these issues may be addressed. With the continuous advances coming from basic research, we provided possible suggestions that may be considered to improve performance of clinical trials and turn ALS research into a 'fertile ground' for drug development for this devastating disease.

Omics Approach to Axonal Dysfunction of Motor Neurons in Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is an intractable adult-onset neurodegenerative disease that leads to the loss of upper and lower motor neurons (MNs). The long axons of MNs become damaged during the early stages of ALS. Genetic and pathological analyses of ALS patients have revealed dysfunction in the MN axon homeostasis. However, the molecular pathomechanism for the degeneration of axons in ALS has not been fully elucidated. This review provides an overview of the proposed axonal pathomechanisms in ALS, including those involving the neuronal cytoskeleton, cargo transport within axons, axonal energy supply, clearance of junk protein, neuromuscular junctions (NMJs), and aberrant axonal branching. To improve understanding of the global changes in axons, the review summarizes omics analyses of the axonal compartments of neurons in vitro and in vivo, including a motor nerve organoid approach that utilizes microfluidic devices developed by this research group. The review also discusses the relevance of intra-axonal transcription factors frequently identified in these omics analyses. Local axonal translation and the relationship among these pathomechanisms should be pursued further. The development of novel strategies to analyze axon fractions provides a new approach to establishing a detailed understanding of resilience of long MN and MN pathology in ALS.

Compassionate Use of the ROCK Inhibitor Fasudil in Three Patients With Amyotrophic Lateral Sclerosis

The Rho kinase (ROCK) inhibitor Fasudil is a promising drug for a disease-modifying therapy of amyotrophic lateral sclerosis (ALS). In preclinical models, Fasudil was shown to increase motor neuron survival, inhibit axonal degeneration, enhance axonal regeneration and modulate microglial function in vitro and in vivo. It prolonged survival and improved motor function of SOD1-G93A-mice. Recently, a phase IIa clinical trial has been commenced to investigate the safety, tolerability, and efficacy of Fasudil in ALS patients at an early stage of disease (ROCK-ALS trial, NCT03792490, Eudra-CT-Nr.: 2017-003676-31). Although Fasudil has been approved in Japan for many years for the treatment of vasospasms following subarachnoid hemorrhage and is known to have a favorable side effect profile in these patients, there is no data on its use in human patients with ALS or any other neurodegenerative conditions. Here, we report the first three cases of compassionate use of Fasudil in patients with ALS. Between May 2017 and February 2019, one male (66 years old) and two female (62 and 68 years old) subjects with probable or definite ALS according to the El Escorial criteria (one of the females having a pathogenic SOD1 mutation) were administered Fasudil 30 mg intravenously twice daily over 45 min on 20 consecutive working days. Blood pressure, heart rate and routine laboratory tests were constantly controlled. All three subjects tolerated the Fasudil infusions well without any obvious side effects. Interestingly, the slow vital capacity showed a significant increase in one of the patients. Taken together, we report here the first compassionate use of the ROCK inhibitor Fasudil in three ALS patients, which was well-tolerated.

Elucidation the binding mechanism of Nelumbo nucifera-derived isoquinoline alkaloids as Rho-kinase 1 inhibitors by molecular docking and dynamic simulation

Rho-kinase 1 (ROCK1) is a key molecular target for controlling smooth muscle (SM) contraction in asthma, gastrointestinal disorders, hypertension. Embryos of lotus seed (Nelumbo nucifera) are traditional folk herbs widely used in treating various diseases which are closely related to SM contraction. With the aim of explaining the mechanism of embryos of lotus seed, 27 isoquinoline alkaloids were isolated from the embryos of lotus seed, the inhibitory activity of these alkaloids against ROCK1 were virtual screened via molecular docking and molecular dynamics (MD) simulations. The docking results indicated that 5 bisbenzylisoquinolines (BBIs) and 1 tribenzylisoquinoline (TBI) were potent inhibitors with high binding affinity for both A and B chains of ROCK1 (AcRock and BcRock). The MD results also revealed that neoliensinine (28) was the most potent inhibitor, which was corresponding to the irreversible relaxation effect of neoliensinine on SM. Moreover, through the MD simulation, it also indicated that neoliensinine (28) interacted in its stretched conformation through polar solvation interactions and van der Waal forces. Finally, with the best calculation results, the inhibition effect of neoliensinine (28) on the contraction of vascular smooth muscle cells (VSMCs) and ROCK1 was also confirmed by several biological tests.Communicated by Ramaswamy H. Sarma.

Glial Cells-The Strategic Targets in Amyotrophic Lateral Sclerosis Treatment

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease, which is characterized by the degeneration of motor neurons in the motor cortex and the spinal cord and subsequently by muscle atrophy. To date, numerous gene mutations have been linked to both sporadic and familial ALS, but the effort of many experimental groups to develop a suitable therapy has not, as of yet, proven successful. The original focus was on the degenerating motor neurons, when researchers tried to understand the pathological mechanisms that cause their slow death. However, it was soon discovered that ALS is a complicated and diverse pathology, where not only neurons, but also other cell types, play a crucial role via the so-called non-cell autonomous effect, which strongly deteriorates neuronal conditions. Subsequently, variable glia-based in vitro and in vivo models of ALS were established and used for brand-new experimental and clinical approaches. Such a shift towards glia soon bore its fruit in the form of several clinical studies, which more or less successfully tried to ward the unfavourable prognosis of ALS progression off. In this review, we aimed to summarize current knowledge regarding the involvement of each glial cell type in the progression of ALS, currently available treatments, and to provide an overview of diverse clinical trials covering pharmacological approaches, gene, and cell therapies.

Dysregulation of Rac or Rho elicits death of motor neurons and activation of these GTPases is altered in the G93A mutant hSOD1 mouse model of amyotrophic lateral sclerosis

Rho GTPases play a central role in neuronal survival; however, the antagonistic relationship between Rac and Rho in the regulation of motor neuron survival remains poorly defined. In the current study, we demonstrate that treatment with NSC23766, a selective inhibitor of the Rac-specific guanine nucleotide exchange factors, Tiam1 and Trio, is sufficient to induce the death of embryonic stem cell (ESC)-derived motor neurons. The mode of cell death is primarily apoptotic and is characterized by caspase-3 activation, de-phosphorylation of ERK5 and AKT, and nuclear translocation of the BH3-only protein Bad. As opposed to the inhibition of Rac, motor neuron cell death is also induced by constitutive activation of Rho, via a mechanism that depends on Rho kinase (ROCK) activity. Investigation of Rac and Rho in the G93A mutant, human Cu, Zn-superoxide dismutase (hSOD1) mouse model of amyotrophic lateral sclerosis (ALS), revealed that active Rac1-GTP is markedly decreased in spinal cord motor neurons of transgenic mice at disease onset and end-stage, when compared to age-matched wild type (WT) littermates. Furthermore, although there is no significant change in active RhoA-GTP, total RhoB displays a striking redistribution from motor neuron nuclei in WT mouse spinal cord to motor neuron axons in end-stage G93A mutant hSOD1 mice. Collectively, these data suggest that the intricate balance between pro-survival Rac signaling and pro-apoptotic Rho/ROCK signaling is critical for motor neuron survival and therefore, disruption in the balance of their activities and/or localization may contribute to the death of motor neurons in ALS.

Synergistic effects of Rho kinase inhibitor Y-27632 and Noggin overexpression on the proliferation and neuron-like cell differentiation of stem cells derived from human exfoliated deciduous teeth

Stem cells from human exfoliated deciduous teeth (SHEDs) are highly proliferative, clonogenic, and multipotent stem cells with a neural crest cell origin. This property could be a desirable option for potential therapeutic applications. In this study, we focus on the effects of Rho kinase inhibitors Y-27632 and Noggin on the proliferation of SHEDs and their differentiation into neuron-like cells. SHEDs were extracted from 10 samples of deciduous teeth obtained from healthy children aged from 5 to 10. The passaged SHEDs were transfected with Noggin, Y-27632, or their combination. By means of MTT and colony formation assays, the effects of Y-27632 and Noggin on cell viability and colony formation were detected. Cellular morphology and neurosphere formation were observed under a microscope. Y-27632 transfection in SHEDs showed enhanced cell viability, colony formation, and neurosphere formation indicating that Y-27632 could promote cell proliferation of SHEDs. Furthermore, we observed that the SHEDs treated with Noggin in combination with Y-27632 displayed typical neuron-like cell morphology and reticular processes. Noggin or Y-27632 alone or in combination induced obviously increased NSE, Nestin, and GFAP levels, which were highest in SHEDs treated with the combination of Noggin and Y-27632. These findings suggest that Y-27632 promotes the proliferation of SHEDs, and Y-27632 and Noggin in combination have a synergistic effect on promoting differentiation of SHEDs into neuron-like cells.

Reducing EphA4 before disease onset does not affect survival in a mouse model of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects motor neurons resulting in severe neurological symptoms. Previous findings of our lab suggested that the axonal guidance tyrosine-kinase receptor EphA4 is an ALS disease-modifying gene. Reduction of EphA4 from developmental stages onwards rescued a motor neuron phenotype in zebrafish, and heterozygous deletion before birth in the SOD1^G93A mouse model of ALS resulted in improved survival. Here, we aimed to gain more insights in the cell-specific role of decreasing EphA4 expression in addition to timing and amount of EphA4 reduction. To evaluate the therapeutic potential of lowering EphA4 later in life, we ubiquitously reduced EphA4 levels to 50% in SOD1^G93A mice at 60 days of age, which did not modify disease parameters. Even further lowering EphA4 levels ubiquitously or in neurons, did not improve disease onset or survival. These findings suggest that lowering EphA4 as target in ALS may suffer from a complex therapeutic time window. In addition, the complexity of the Eph-ephrin signalling system may also possibly limit the therapeutic potential of such an approach in ALS. We suggest here that a specific EphA4 knockdown in adulthood may have a limited therapeutic potential for ALS.

Nonphosphorylatable Src Ser75 Mutation Increases Ethanol Preference and Consumption in Mice

Src is highly expressed in CNS neurons and contributes not only to developmental proliferation and differentiation but also to high-order brain functions, such as those contributing to alcohol consumption. Src knock-out mice exhibit no CNS abnormalities, presumably due to compensation by other Src family kinases (SFKs), but have a shortened lifespan and osteopetrosis-associated defects, impeding investigations of the role of Src on behavior in adult mice. However, the Unique domain of Src differs from those in other SFKs and is phosphorylated by cyclin-dependent kinase 1 (Cdk1) and Cdk5 at Ser75, which influences its postmitotic function in neurons. Therefore, ethanol consumption in mice harboring nonphosphorylatable (Ser75Ala) or phosphomimetic (Ser75Asp) Src mutants was investigated. Mice harboring the Ser75Ala Src mutant, but not the Ser75Asp mutant, had a higher preference for and consumption of solutions containing 5% and 10% ethanol than wild-type mice. However, plasma ethanol concentrations and sensitivities to the sedative effects of ethanol were not different among the groups. In mice harboring the Ser75Ala Src mutant, the activity of Rho-associated kinase (ROCK) in the striatum was significantly lower and Akt Ser473 phosphorylation was significantly higher than in wild-type mice. These results suggest that Src regulates voluntary ethanol drinking in a manner that depends on Ser75 phosphorylation.

ROCK inhibition improves axonal regeneration in a preclinical model of amyotrophic lateral sclerosis

Alteration of the RhoA/ROCK (Rho kinase) pathway has been shown to be neuroprotective in SOD1^G93A mice, the most commonly used animal model of ALS. Since previous studies indicate that, apart from neuroprotection, ROCK inhibitor Y-27632 can also accelerate regeneration of motor axons, we here assessed the regenerative capability of axons in SOD1^G93A mice with and without treatment with Y-27632. Regeneration of axons was examined after sciatic nerve crush in pre- and symptomatic SOD1^G93A mice. Proregenerative effects of Y-27632 were studied during the disease course in the SOD1^G93A mouse model. In symptomatic SOD1^G93A mice, axonal regeneration was markedly reduced compared to presymptomatic SOD1^G93A mice and wild types. Treatment with Y-27632 improved functional and morphological measures of motor axons after sciatic crush in all tested conditions. Y-27632 treatment did not increase the lifespan of symptomatic SOD1^G93A mice, but did improve axonal (re)innervation of neuromuscular junctions. Our study provides proof of concept that axonal regeneration of motor neurons harboring SOD1^G93A is impaired, but amenable for pharmacological interventions aiming to accelerate axonal regeneration. Given the lack of treatments for ALS, approaches to improve axonal regeneration, including by inhibiting ROCK, should be further explored.

ROCK-ALS: Protocol for a Randomized, Placebo-Controlled, Double-Blind Phase IIa Trial of Safety, Tolerability and Efficacy of the Rho Kinase (ROCK) Inhibitor Fasudil in Amyotrophic Lateral Sclerosis

Objectives: Disease-modifying therapies for amyotrophic lateral sclerosis (ALS) are still not satisfactory. The Rho kinase (ROCK) inhibitor fasudil has demonstrated beneficial effects in cell culture and animal models of ALS. For many years, fasudil has been approved in Japan for the treatment of vasospasm in patients with subarachnoid hemorrhage with a favorable safety profile. Here we describe a clinical trial protocol to repurpose fasudil as a disease-modifying therapy for ALS patients. Methods: ROCK-ALS is a multicenter, double-blind, randomized, placebo-controlled phase IIa trial of fasudil in ALS patients (EudraCT: 2017-003676-31, NCT: 03792490). Safety and tolerability are the primary endpoints. Efficacy is a secondary endpoint and will be assessed by the change in ALSFRS-R, ALSAQ-5, slow vital capacity (SVC), ECAS, and the motor unit number index (MUNIX), as well as survival. Efficacy measures will be assessed before (baseline) and immediately after the infusion therapy as well as on days 90 and 180. Patients will receive a daily dose of either 30 or 60 mg fasudil, or placebo in two intravenous applications for a total of 20 days. Regular assessments of safety will be performed throughout the treatment period, and in the follow-up period until day 180. Additionally, we will collect biological fluids to assess target engagement and evaluate potential biomarkers for disease progression. A total of 120 patients with probable or definite ALS (revised El Escorial criteria) and within 6-18 months of the onset of weakness shall be included in 16 centers in Germany, Switzerland and France. Results and conclusions: The ROCK-ALS trial is a phase IIa trial to evaluate the ROCK-inhibitor fasudil in early-stage ALS-patients that started patient recruitment in 2019.

The protective effect of non-invasive low intensity pulsed electric field and fucoidan in preventing oxidative stress-induced motor neuron death via ROCK/Akt pathway

With the expansion of the aged population, it is predicted that neurodegenerative diseases (NDDs) will become a major threat to public health worldwide. However, existing therapies can control the symptoms of the diseases at best, rather than offering a fundamental cure. As for the complex pathogenesis, clinical and preclinical researches have indicated that oxidative stress, a central role in neuronal degeneration, is a possible therapeutic target in the development of novel remedies. In this study, the motor neuron-like cell line NSC-34 was employed as an experimental model in probing the effects induced by the combination of non-invasive low intensity pulsed electric field (LIPEF) and fucoidan on the H₂O₂-induced neuron damage. It was found that single treatment of the LIPEF could protect the NSC-34 cells from oxidative stress, and the protective effect was enhanced by combining the LIPEF and fucoidan. Notably, it was observed that single treatment of the LIPEF obviously suppressed the H₂O₂-enhanced expression of ROCK protein and increased the phosphorylation of Akt in the H₂O₂-treated NSC-34 cells. Moreover, the LIPEF can be easily modified to concentrate on a specific area. Accordingly, this technique can be used as an advanced remedy for ROCK inhibition without the drawback of drug metabolism. Therefore, we suggest the LIPEF would be a promising strategy as a treatment for motor neurodegeneration and warrant further probe into its potential in treating other neuronal degenerations.

Suppression of glioblastoma by a drug cocktail reprogramming tumor cells into neuronal like cells

Glioblastoma (GBM) is the most common and aggressive malignant tumor in adult brain. Even with the current standard therapy including surgical resection followed by postoperative radiotherapy and chemotherapy with temozolomide (Temo), GBM patients still have a poor median survival. Reprogramming of tumor cells into non-malignant cells might be a promising therapeutic strategy for malignant tumors, including GBM. Based on previous studies using small molecules to reprogram astrocytes into neuronal cells, here we further identified a FTT cocktail of three commonly used drugs (Fasudil, Tranilast, and Temo) to reprogram patient-derived GBM cells, either cultured in serum containing or serum-free medium, into neuronal like cells. FTT-treated GBM cells displayed a neuronal like morphology, expressed neuronal genes, exhibited neuronal electrophysiological properties, and showed attenuated malignancy. More importantly, FTT cocktail more significantly suppressed tumor growth and prolonged survival in GBM patient derived xenograft than Temo alone. Our study provided preclinical evidence that the neuronal reprogramming drug cocktail might be a promising strategy to improve the existing treatment for GBM.

Neuropeptide VGF-Derived Peptide LQEQ-19 has Neuroprotective Effects in an In Vitro Model of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease caused by the loss of upper and lower motor neurons resulting in muscle weakness and paralysis. Recently, VGF, a neuropeptide that is a precursor of bioactive polypeptides, was found to be decreased in ALS patients, and its inducer exerted protective effects in models of ALS. These findings suggested that VGF was involved in the pathology of ALS. Here, we investigated the neuroprotective effects of various VGF-derived peptides in an in vitro ALS model. We applied seven VGF-derived peptides (TLQP-21, AQEE-30, AQEE-11, LQEQ-19, QEEL-16, LENY-13, and HVLL-7) to the motor neuron-derived cell line, NSC-34, expressing SOD1^G93A, which is one of the mutated proteins responsible for familial ALS. Nuclear staining revealed that AQEE-30 and LQEQ-19, which are derived from the C-terminal polypeptide of the VGF precursor protein, attenuated neuronal cell death. Furthermore, immunoblot analysis demonstrated that LQEQ-19 promoted the phosphorylation of Akt and extracellular signal-regulated kinase (ERK) 1/2, and inhibiting these mitogen-activated MAP kinases (MAPKs) with phosphoinositide 3-kinase or MEK/ERK inhibitors, eliminated the neuroprotective effects of LQEQ-19. In conclusion, these results suggest that VGF C-terminal peptides exert their neuroprotective effects via activation of MAPKs such as Akt and ERK1/2. Furthermore, these findings indicate that VGF-derived peptides have potential application in ALS therapy.