Laquinimod (ABR-215062) suppresses the development of experimental autoimmune encephalomyelitis, modulates the Th1/Th2 balance and induces the Th3 cytokine TGF-beta in Lewis rats

Exploring immunotherapeutic strategies for neurodegenerative diseases: a focus on Huntington's disease and Prion diseases

Immunotherapy has emerged as a promising therapeutic approach for the treatment of neurodegenerative disorders, which are characterized by the progressive loss of neurons and impaired cognitive functions. In this review, active and passive immunotherapeutic strategies that help address the underlying pathophysiology of Huntington's disease (HD) and prion diseases by modulating the immune system are discussed. The current landscape of immunotherapeutic strategies, including monoclonal antibodies and vaccine-based approaches, to treat these diseases is highlighted, along with their potential benefits and mechanisms of action. Immunotherapy generally works by targeting disease-specific proteins, which serve as the pathological hallmarks of these diseases. Additionally, the review addresses the challenges and limitations associated with immunotherapy. For HD, immunotherapeutic approaches focus on neutralizing the toxic effects of mutant huntingtin and tau proteins, thereby reducing neurotoxicity. Immunotherapeutic approaches targeting flanking sequences, rather than the polyglutamine tract in the mutant huntingtin protein, have yielded promising outcomes for patients with HD. In prion diseases, therapies attempt to prevent or eliminate misfolded proteins that cause neurodegeneration. The major challenge in prion diseases is immune tolerance. Approaches to overcome the highly tolerogenic nature of the prion protein have been discussed. A common hurdle in delivering antibodies is the blood‒brain barrier, and strategies that can breach this barrier are being investigated. As protein aggregation and neurotoxicity are related, immunotherapeutic strategies being developed for other neurodegenerative diseases could be repurposed to target protein aggregation in HD and prion diseases. While significant advances in this field have been achieved, continued research and development are necessary to overcome the existing limitations, which will help in shaping the future of immunotherapy as a strategy for managing neurological disorders.

Disease-modifying therapy in progressive multiple sclerosis: a systematic review and network meta-analysis of randomized controlled trials

Background

Currently, disease-modifying therapies (DMTs) for progressive multiple sclerosis (PMS) are widely used in clinical practice. At the same time, there are a variety of drug options for DMTs, but the effect of the drugs that can better relieve symptoms and improve the prognosis are still inconclusive.

Objectives

This systematic review aimed to evaluate the efficacy and safety of DMTs for PMS and to identify the best among these drugs.

Methods

MEDLINE, EMBASE, the Cochrane Library, and clinicaltrials.gov were systematically searched to identify relevant studies published before 30 January, 2023. We assessed the certainty of the evidence using the confidence in the network meta-analysis (CINeMA) framework. We estimated the summary risk ratio (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes with 95% credible intervals (CrIs).

Results

We included 18 randomized controlled trials (RCTs) involving 9,234 patients in the study. DMT can effectively control the disease progression of MS. Among them, mitoxantrone, siponimod, and ocrelizumab are superior to other drug options in delaying disease progression (high certainty). Mitoxantrone was the best (with high certainty) for mitigating deterioration (progression of disability). Ocrelizumab performed best on the pre- and post-treatment Timed 25-Foot Walk test (T25FW; low certainty), as did all other agents (RR range: 1.12-1.05). In the 9-Hole Peg Test (9HPT), natalizumab performed the best (high certainty), as did all other agents (RR range: 1.59-1.09). In terms of imaging, IFN-beta-1b performed better on the new T2 hypointense lesion on contrast, before and after treatment (high certainty), while siponimod performed best on the change from baseline in the total volume of lesions on T2-weighted image contrast before and after treatment (high certainty), and sWASO had the highest area under the curve (SUCRA) value (100%). In terms of adverse events (AEs), rituximab (RR 1.01), and laquinimod (RR 1.02) were more effective than the placebo (high certainty). In terms of serious adverse events (SAEs), natalizumab (RR 1.09), and ocrelizumab (RR 1.07) were safer than placebo (high certainty).

Conclusion

DMTs can effectively control disease progression and reduce disease deterioration during the treatment of PMS.

Systematic review registration

https://inplasy.com/?s=202320071, identifier: 202320071.

Mechanistic Insights, Treatment Paradigms, and Clinical Progress in Neurological Disorders: Current and Future Prospects

Neurodegenerative diseases (NDs) are a major cause of disability and are related to brain development. The neurological signs of brain lesions can vary from mild clinical shortfalls to more delicate and severe neurological/behavioral symptoms and learning disabilities, which are progressive. In this paper, we have tried to summarize a collective view of various NDs and their possible therapeutic outcomes. These diseases often occur as a consequence of the misfolding of proteins post-translation, as well as the dysfunctional trafficking of proteins. In the treatment of neurological disorders, a challenging hurdle to cross regarding drug delivery is the blood-brain barrier (BBB). The BBB plays a unique role in maintaining the homeostasis of the central nervous system (CNS) by exchanging components between the circulations and shielding the brain from neurotoxic pathogens and detrimental compounds. Here, we outline the current knowledge about BBB deterioration in the evolving brain, its origin, and therapeutic interventions. Additionally, we summarize the physiological scenarios of the BBB and its role in various cerebrovascular diseases. Overall, this information provides a detailed account of BBB functioning and the development of relevant treatments for neurological disorders. This paper will definitely help readers working in the field of neurological scientific communities.

Targeting receptor-ligand chemistry for drug delivery across blood-brain barrier in brain diseases

The blood-brain barrier (BBB) is composed of a layer of endothelial cells that is interspersed with a series of tight junctions and characterized by the absence of fenestrations. The permeability of this barrier is controlled by junctions such as tight junctions and adherent junctions as well as several cells such as astrocytes, pericytes, vascular endothelial cells, neurons, microglia, and efflux transporters with relatively enhanced expression. It plays a major role in maintaining homeostasis in the brain and exerts a protective regulatory control on the influx and efflux of molecules. However, it proves to be a challenge for drug delivery strategies that target brain diseases like Dementia, Parkinson's Disease, Alzheimer's Disease, Brain Cancer or Stroke, Huntington's Disease, Lou Gehrig's Disease, etc. Conventional modes of drug delivery are invasive and have been known to contribute to a "leaky BBB", recent studies have highlighted the efficiency and relative safety of receptor-mediated drug delivery. Several receptors are exhibited on the BBB, and actively participate in nutrient uptake, and recognize specific ligands that modulate the process of endocytosis. The strategy employed in receptor-mediated drug delivery exploits this process of "tricking" the receptors into internalizing ligands that are conjugated to carrier systems like liposomes, nanoparticles, monoclonal antibodies, enzymes etc. These in turn are modified with drug molecules, therefore leading to delivery to desired target cells in brain tissue. This review comprehensively explores each of those receptors that can be modified to serve such purposes as well as the currently employed strategies that have led to increased cellular uptake and transport efficiency.

Aryl Hydrocarbon Receptor Activation in Astrocytes by Laquinimod Ameliorates Autoimmune Inflammation in the CNS

Objective

MS is an autoimmune demyelinating disease of the CNS, which causes neurologic deficits in young adults and leads to progressive disability. The aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, can drive anti-inflammatory functions in peripheral immune cells and also in CNS-resident cells. Laquinimod is a drug developed for the treatment of MS known to activate AHR, but the cellular targets of laquinimod are still not completely known. In this work, we analyzed the contribution of AHR activation in astrocytes to its beneficial effects in the experimental autoimmune encephalomyelitis (EAE) preclinical model of MS.

Methods

We used conditional knockout mice, in combination with genome-wide analysis of gene expression by RNA-seq and in vitro culture systems to investigate the effects of laquinimod on astrocytes.

Results

We found that AHR activation in astrocytes by laquinimod ameliorates EAE, a preclinical model of MS. Genome-wide RNA-seq transcriptional analyses detected anti-inflammatory effects of laquinimod in glial cells during EAE. Moreover, we established that the Delaq metabolite of laquinimod dampens proinflammatory mediator production while activating tissue-protective mechanisms in glia.

Conclusions

Taken together, these findings suggest that AHR activation by clinically relevant AHR agonists may represent a novel therapeutic approach for the treatment of MS.

Laquinimod dampens IL-1β signaling and Th17-polarizing capacity of monocytes in patients with MS

OBJECTIVE

To assess the impact of laquinimod treatment on monocytes and to investigate the underlying immunomodulatory mechanisms in MS.

METHODS

In this cross-sectional study, we performed in vivo and in vitro analyses of cluster of differentiation (CD14⁺) monocytes isolated from healthy donors (n = 15), untreated (n = 13), and laquinimod-treated patients with MS (n = 14). Their frequency and the expression of surface activation markers were assessed by flow cytometry and the viability by calcein staining. Cytokine concentrations in the supernatants of lipopolysaccharide (LPS)-stimulated monocytes were determined by flow cytometry. The messenger ribonucleic acid (mRNA) expression level of genes involved in cytokine expression was measured by quantitative PCR. The LPS-mediated nuclear factor kappa-light-chain-enhancer of activated B-cell (NF-κB) activation was determined by the quantification of the phosphorylation level of the p65 subunit. Laquinimod-treated monocytes were cocultured with CD4⁺ T cells, and the resulting cytokine production was analyzed by flow cytometry after intracellular cytokine staining. The interleukin (IL)-17A concentration of the supernatant was assessed by ELISA.

RESULTS

Laquinimod did not alter the frequency or viability of circulating monocytes, but led to an upregulation of CD86 expression. LPS-stimulated monocytes of laquinimod-treated patients with MS secreted less IL-1β following a downregulation of IL-1β gene expression. Phosphorylation levels of the NF-κB p65 subunit were reduced after laquinimod treatment, indicating a laquinimod-associated inhibition of the NF-κB pathway. T cells primed with laquinimod-treated monocytes differentiated significantly less into IL-17A-producing T helper (Th)-17 cells.

CONCLUSIONS

Our findings suggest that inhibited NF-κB signaling and downregulation of IL-1β expression in monocytes contributes to the immunomodulatory effects of laquinimod and that the impairment of Th17 polarization might mediate its disease-modifying activity in MS.

Laquinimod exerts anti-inflammatory and antiapoptotic effects in retinal ischemia/reperfusion injury

Retinal ischemia/reperfusion (I/R) occurs in various vision disabled ocular diseases, involved in acute glaucoma, diabetic retinopathy, ischemic optic neuropathy, hypertensive retinopathy and retinal vascular occlusion. Laquinimod (LQ), a new type of immunosuppressant, has been reported to exert anti-inflammatory effects on autoimmune diseases. This research aims to investigate the protective effect of LQ on I/R damage by focusing on inhibiting dysregulated neuroinflammation and neuronal apoptosis. In our study, mice were treated with LQ after high intraocular pressure (IOP)-induced retinal I/R injury. The data showed that LQ significantly attenuated high IOP-induced retinal ganglion cell (RGC) death and inner plexiform layer (IPL) thinning and inhibited microglial activation. The results of qRT-PCR, flow cytometry and Luminex multiplex assays demonstrated the anti-inflammatory action of LQ in BV2 cells stimulated with lipopolysaccharide (LPS). In addition, primary RGC apoptosis induced by oxygen-glucose deprivation/reperfusion (OGD/R) was also directly suppressed by LQ. Importantly, LQ inhibited the expression of cleaved caspase-8 and the downstream NLRP3 inflammasome and IL-1β. In conclusion, our findings offer the first evidence that LQ treatment prevents retinal I/R damage. Furthermore, LQ could directly inhibit RGC apoptosis. Caspase-8 activation and subsequent inflammation can also be suppressed by LQ, which suggests that LQ may act through inhibiting the caspase-8 pathway. This study demonstrates a new mechanism of LQ and provides beneficial preclinical data for the clinical application of LQ.

Laquinimod Prevents Adipogenesis and Obesity by Down-Regulating PPAR-γ and C/EBPα through Activating AMPK

BACKGROUND AND PURPOSE

obesity is defined as excessive accumulation of adipose tissues and is becoming one of the main global severe public health issues. The present study aims to investigate the anti-adipogenesis of laquinimod and the underlying mechanism.

METHODS

a differentiation cocktail was used to differentiate 3T3-L1 cells, and mice were fed with high fat food to establish the obesity animal model. Oil red O staining, glycerol production assay, and the release of triglyceride were used to evaluate the differentiation degree of 3T3-L1 cells. The expression level of sterol regulatory element binding transcription factor 1 (Srebp1), fatty acid binding protein-4 (FABP4), glucose transporter 4 (GLUT4), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT enhancer-binding proteins (C/EBPα), and phosphorylation of adenosine 5'-monophosphate (AMP)-activated protein kinase α (p-AMPKα) was determined by quantitative real time PCRqRT-PCR and western blot analysis. The pathological state of adipose tissues was evaluated by hematoxylin-eosin staining.

RESULTS

the amount and UV absorption of oil red O, glycerol production, release of triglyceride, and the expression of SREBP1, FABP4, and Glut4 in differentiated 3T3-L1 cells were decreased by the administration of laquinimod. PPAR-γ and C/EBPα were down-regulated, and p-AMPKα was up-regulated by laquinimod. The down-regulated PPAR-γ and C/EBPα, as well as the inhibited lipid accumulation functioned by laquinimod, were reversed by the coincubation with the AMPK inhibitor compound C. Decreased body weight, visceral adipocyte tissue weight, and size of adipocytes were observed in in vivo obesity mice after administration with laquinimod.

CONCLUSION

laquinimod might prevent adipogenesis by down-regulating PPAR-γ and C/EBPα through activating AMPK.

Immunotherapies in Huntington's disease and α-Synucleinopathies

Modulation of immune activation using immunotherapy has attracted considerable attention for many years as a potential therapeutic intervention for several inflammation-associated neurodegenerative diseases. However, the efficacy of single-target immunotherapy intervention has shown limited or no efficacy in alleviating disease burden and restoring functional capacity. Marked immune system activation and neuroinflammation are important features and prodromal signs in polyQ repeat disorders and α-synucleinopathies. This review describes the current status and future directions of immunotherapies in proteinopathy-induced neurodegeneration with emphasis on preclinical and clinical efficacies of several anti-inflammatory compounds and antibody-based therapies for the treatment of Huntington's disease and α-synucleinopathies. The review concludes with how disease modification and functional restoration could be achieved by using targeted multimodality therapy to target multiple factors.

Laquinimod ameliorates secondary brain inflammation

Accumulating evidence suggests that a degenerative processes within the brain can trigger the formation of new, focal inflammatory lesions in Multiple Sclerosis (MS). Here, we used a novel pre-clinical MS animal model to test whether the amelioration of degenerative brain events reduces the secondary recruitment of peripheral immune cells and, in consequence, inflammatory lesion development. Neural degeneration was induced by a 3 weeks cuprizone intoxication period. To mitigate the cuprizone-induced pathology, animals were treated with Laquinimod (25 mg/kg) during the cuprizone-intoxication period. At the beginning of week 6, encephalitogenic T cell development in peripheral lymphoid organs was induced by the immunization with myelin oligodendrocyte glycoprotein 35-55 peptide (i.e., Cup/EAE). Demyelination, axonal injury and reactive gliosis were determined by immunohistochemistry. Positron emission tomography (PET) imaging was performed to analyze glia activation in vivo. Vehicle-treated cuprizone mice displayed extensive callosal demyelination, glia activation and enhanced TSPO-ligand binding. This cuprizone-induced pathology was profoundly ameliorated in mice treated with Laquinimod. In vehicle-treated Cup/EAE mice, the cuprizone-induced pathology triggered massive peripheral immune cell recruitment into the forebrain, evidenced by multifocal perivascular inflammation, glia activation and neuro-axonal injury. While anti myelin oligodendrocyte glycoprotein 35-55 peptide immune responses were comparable in vehicle- and Laquinimod-treated Cup/EAE mice, the cuprizone-triggered immune cell recruitment was ameliorated by the Laquinimod treatment. This study clearly illustrates that amelioration of a primary brain-intrinsic degenerative process secondary halts peripheral immune cell recruitment and, in consequence, inflammatory lesion development. These findings have important consequences for the interpretation of the results of clinical studies.

Cortical and meningeal pathology in progressive multiple sclerosis: a new therapeutic target?

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease that involves an intricate interaction between the central nervous system and the immune system. Nevertheless, its etiology is still unknown. MS exhibits different clinical courses: recurrent episodes with remission periods ('relapsing-remitting') that can evolve to a 'secondary progressive' form or persistent progression from the onset of the disease ('primary progressive'). The discovery of an effective treatment and cure has been hampered due to the pathological and clinical heterogeneity of the disease. Historically, MS has been considered as a disease exclusively of white matter. However, patients with progressive forms of MS present with cortical lesions associated with meningeal inflammation along with physical and cognitive disabilities. The pathogenesis of the cortical lesions has not yet been fully described. Animal models that represent both the cortical and meningeal pathologies will be critical in addressing MS pathogenesis as well as the design of specific treatments. In this review, we will address the state-of-the-art diagnostic and therapeutic alternatives and the development of strategies to discover new therapeutic approaches, especially for the progressive forms.

Transcriptomic Impact of IMA-08401, a Novel AHR Agonist Resembling Laquinimod, on Rat Liver

IMA-08401 (C2) is a novel aryl hydrocarbon receptor (AHR) agonist and selective AHR modulator (SAHRM) that is structurally similar to laquinimod (LAQ). Both compounds are converted to the AHR-active metabolite DELAQ (IMA-06201) in vivo. SAHRMs have been proposed as therapeutic options for various autoimmune disorders. Clinical trials on LAQ have not reported any significant toxic outcomes and C2 has shown low toxicity in rats; however, their functional resemblance to the highly toxic AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) raises questions. Here, we characterize the hepatic transcriptomic changes induced by acute (single-dose) and subacute exposure (repeated dosing for 5 days followed by a 5-day recovery period) to C2 in Sprague-Dawley rats. Exposure to C2 leads to activation of the AHR, as shown by altered transcription of Cyp1a1. We identify a heightened response early after exposure that drops off by day 10. Acute exposure to C2 leads to changes to transcription of genes involved in antiviral and antibacterial responses, which highlights the immunomodulator effects of this AHR agonist. Subacute exposure causes an oxidative stress response in the liver, the consequences of which require further study on target tissues such as the CNS and immune system, both of which may be compromised in this patient population.

Laquinimod protects the optic nerve and retina in an experimental autoimmune encephalomyelitis model

BACKGROUND

The oral immunomodulatory agent laquinimod is currently evaluated for multiple sclerosis (MS) treatment. Phase II and III studies demonstrated a reduction of degenerative processes. In addition to anti-inflammatory effects, laquinimod might have neuroprotective properties, but its impact on the visual system, which is often affected by MS, is unknown. The aim of our study was to investigate potential protective effects of laquinimod on the optic nerve and retina in an experimental autoimmune encephalomyelitis (EAE) model.

METHODS

We induced EAE in C57/BL6 mice via MOG_35-55 immunization. Animals were divided into an untreated EAE group, three EAE groups receiving laquinimod (1, 5, or 25 mg/kg daily), starting the day post-immunization, and a non-immunized control group. Thirty days post-immunization, scotopic electroretinograms were carried out, and mice were sacrificed for histopathology (HE, LFB), immunohistochemistry (MBP, Iba1, Tmem119, F4/80, GFAP, vimentin, Brn-3a, cleaved caspase 3) of the optic nerve and retina, and retinal qRT-PCR analyses (Brn-3a, Iba1, Tmem119, AMWAP, CD68, GFAP). To evaluate the effect of a therapeutic approach, EAE animals were treated with 25 mg/kg laquinimod from day 16 when 60% of the animals had developed clinical signs of EAE.

RESULTS

Laquinimod reduced neurological EAE symptoms and improved the neuronal electrical output of the inner nuclear layer compared to untreated EAE mice. Furthermore, cellular infiltration, especially recruited phagocytes, and demyelination in the optic nerve were reduced. Microglia were diminished in optic nerve and retina. Retinal macroglial signal was reduced under treatment, whereas in the optic nerve macroglia were not affected. Additionally, laquinimod preserved retinal ganglion cells and reduced apoptosis. A later treatment with laquinimod in a therapeutic approach led to a reduction of clinical signs and to an improved b-wave amplitude. However, no changes in cellular infiltration and demyelination of the optic nerves were observed. Also, the number of retinal ganglion cells remained unaltered.

CONCLUSION

From our study, we deduce neuroprotective and anti-inflammatory effects of laquinimod on the optic nerve and retina in EAE mice, when animals were treated before any clinical signs were noted. Given the fact that the visual system is frequently affected by MS, the agent might be an interesting subject of further neuro-ophthalmic investigations.

Clinical Trials Corner: September 2017

Clinical Trials Corner of Journal of Huntington’s Disease will regularly review ongoing and recently completed clinical trials in Huntington’s disease. In this inaugural issue, we list all currently registered and ongoing clinical trials, expand on LEGATO-HD and IONIS-HTT_Rx, and cover two recently finished trials: Amaryllis and Pride-HD.

Paquinimod prevents development of diabetes in the non-obese diabetic (NOD) mouse

Quinoline-3-carboxamides (Q compounds) are immunomodulatory compounds that have shown efficacy both in autoimmune disease and cancer. We have in here investigated the impact of one such compound, paquinimod, on the development of diabetes in the NOD mouse model for type I diabetes (T1D). In cohorts of NOD mice treated with paquinimod between weeks 10 to 20 of age and followed up until 40 weeks of age, we observed dose-dependent reduction in incidence of disease as well as delayed onset of disease. Further, in contrast to untreated controls, the majority of NOD mice treated from 15 weeks of age did not develop diabetes at 30 weeks of age. Importantly, these mice displayed significantly less insulitis, which correlated with selectively reduced number of splenic macrophages and splenic Ly6Chi inflammatory monocytes at end point as compared to untreated controls. Collectively, these results demonstrate that paquinimod treatment can significantly inhibit progression of insulitis to T1D in the NOD mouse. We propose that the effect of paquinimod on disease progression may be related to the reduced number of these myeloid cell populations. Our finding also indicates that this compound could be a candidate for clinical development towards diabetes therapy in humans.

The Role of Astrocytes in Multiple Sclerosis

The role traditionally assigned to astrocytes in the pathogenesis of multiple sclerosis (MS) lesions has been the formation of the glial scar once inflammation has subsided. Astrocytes are now recognized to be early and highly active players during lesion formation and key for providing peripheral immune cells access to the central nervous system. Here, we review the role of astrocytes in the formation and evolution of MS lesions, including the recently described functional polarization of astrocytes, discuss prototypical pathways for astrocyte activation, and summarize mechanisms by which MS treatments affect astrocyte function.

Microglial Phenotypes and Functions in Multiple Sclerosis

Microglia are the resident immune cells that constantly survey the central nervous system. They can adapt to their environment and respond to injury or insult by altering their morphology, phenotype, and functions. It has long been debated whether microglial activation is detrimental or beneficial in multiple sclerosis (MS). Recently, the two opposing yet connected roles of microglial activation have been described with the aid of novel microglial markers, RNA profiling, and in vivo models. In this review, microglial phenotypes and functions in the context of MS will be discussed with evidence from both human pathological studies, in vitro and in vivo models. Microglial functional diversity-phagocytosis, antigen presentation, immunomodulation, support, and repair-will also be examined in detail. In addition, this review discusses the emerging evidence for microglia-related targets as biomarkers and therapeutic targets for MS.

Laquinimod attenuates inflammation by modulating macrophage functions in traumatic brain injury mouse model

Background

Traumatic brain injury (TBI) is a critical public health and socio-economic problem worldwide. A growing body of evidence supports the involvement of inflammatory events in TBI. It has been reported that resident microglia and infiltrating monocytes promote an inflammatory reaction that leads to neuronal death and eventually behavioral and cognitive impairment. Currently, there is no effective treatment for TBI and the development of new therapeutic strategies is a scientific goal of highest priority. Laquinimod, an orally administered neuroimmunomodulator initially developed for the treatment of multiple sclerosis, might be a promising neuroprotective therapy for TBI. Herein, we aim to investigate the hypothesis that laquinimod will reduce the central nervous system (CNS) damage caused by TBI.

Methods

To test our hypothesis, Ccr2^rfp/+Cx3cr1^gfp/+ mice were submitted to a moderate TBI induced by fluid percussion. Sham controls were submitted only to craniotomy. Mice were treated daily by oral gavage with laquinimod (25 mg/kg) 7 days before and 3 days after TBI. The brains of mice treated or not treated with laquinimod were collected at 3 and 120 days post injury, and brain morphological changes, axonal injury, and neurogenesis were evaluated by microscopy analysis. We also isolated microglia from infiltrating monocytes, and the expression of immune gene mRNAs were analyzed by employing a quantitative NanoString nCounter technique.

Results

Laquinimod prevented ventricle enlargement caused by TBI in the long term. Immunohistochemical analyses revealed decreased axonal damage and restored neurogenesis in the laquinimod-treated TBI group at early stage (3 days post injury). Notably, laquinimod inhibited the monocytes infiltration to the brain. Hierarchial clustering demonstrated that the microglial gene expression from the TBI group treated with laquinimod resembles the sham group more than the TBI-water control group.

Conclusions

Administration of laquinimod reduced lesion volume and axonal damage and restored neurogenesis after TBI. Laquinimod might be a potential therapy strategy to improve TBI long-term prognosis.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1075-y) contains supplementary material, which is available to authorized users.

Safety and in vivo immune assessment of escalating doses of oral laquinimod in patients with RRMS

Background

Laquinimod is an oral immunomodulator in clinical development to treat relapsing-remitting multiple sclerosis (RRMS). Laquinimod is in clinical development for the treatment of multiple sclerosis and Huntington Disease (HD). The objective of this study is to assess the safety, tolerability, pharmacokinetics (PK) and cytoimmunologic effects following escalating doses of laquinimod in patients with RRMS.

Methods

One hundred twelve patients were randomly assigned to laquinimod/placebo in a series of separate dose-escalating cohorts starting from a daily oral dose of 0.9 mg/1.2 mg escalating to 2.7 mg, in 0.3 mg increments.

Results

Twenty-eight patients received placebo and 84 received laquinimod ranging from 0.9 to 2.7 mg. No deaths occurred. One serious adverse event (SAE) of perichondritis was reported, which was unrelated to laquinimod (0.9 mg). There was no increased incidence of adverse events (AEs) with escalating doses. Laquinimod-treated patients showed more abnormal laboratory levels in liver enzymes, P-amylase, C-reactive protein (CRP), and fibrinogen, but most shifts were clinically non-significant. The exposure of laquinimod was dose proportional and linear in the tested dose range. An immunological substudy showed significant dose-dependent decreases in 6-sulpho LacNAc + dendritic cell (slanDC) frequency following laquinimod compared to placebo.

Conclusion

Laquinimod doses up to 2.7 mg were safely administered to patients with RRMS. An in vivo effect of laquinimod on the innate immune system was demonstrated.

Trial registration

EudraCT Number: 2009-011234-99. Registered 23 June 2009.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0945-z) contains supplementary material, which is available to authorized users.

Laquinimod has no effects on brain volume or cellular CNS composition in the F1 3xTg-AD/C3H mouse model of Alzheimer's disease

BACKGROUND

Laquinimod is an anti-inflammatory agent with good central nervous system (CNS) bioavailability, and neuroprotective and myelorestorative properties. A clinical trial in patients with multiple sclerosis demonstrated that laquinimod significantly reduced loss of brain volume. The cellular substrate or molecular events underlying that treatment effect are unknown. In this study, we aimed to explore laquinimod's potential effects on brain volume, animal behavior, cellular numbers and composition of CNS-intrinsic cells and mononuclear cells within the CNS, amyloid beta (Aβ) accumulation and tau phosphorylation in the F1 3xTg-AD/C3H mouse model of Alzheimer's disease.

METHODS

Utilizing a dose response study design, four months old F1 3xTg-AD/C3H mice were treated for 10months between ages 4 and 14months with laquinimod (5, 10, or 25mg/kg), or PBS administered by oral gavage. Brain volumes were measured in a 7 Tesla magnetic resonance imager (MRI) at ages 4 and 14months. Behavioral testing included locomotor and rearing activity and the Morris water maze task. Cell numbers and immunophenotypes were assessed by multiparameter flow cytometry. Aβ deposition and tau phosphorylation were determined by immunohistochemistry.

RESULTS

In the F1 3xTg-AD/C3H animal model of AD, there was no detectable reduction of brain volume over a period of 10months of treatment, as there was not brain atrophy in any of the placebo or treatment groups. Laquinimod had no detectable effects on most neurobehavioral outcomes. The number or composition of CNS intrinsic cells and mononuclear subsets isolated from the CNS were not altered by laquinimod.

CONCLUSION

This is the first demonstration that there are no age-associated brain volume changes in the F1 3xTg-AD/C3H mouse model of Alzheimer's disease. Consequently, laquinimod had no effect on that outcome of this study. Most secondary outcomes on the effects of laquinimod on behavior and the number and composition of CNS-intrinsic cells and mononuclear cells within the CNS were also negative.

Laquinimod enhances central nervous system barrier functions

Laquinimod is currently being tested as a therapeutic drug in multiple sclerosis. However, its exact mechanism of action is still under investigation. Tracking of fluorescently-tagged encephalitogenic T cells during experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, revealed that laquinimod significantly reduces the invasion of pathogenic effector T cells into the CNS tissue. T-cell activation, differentiation and amplification within secondary lymphoid organs after immunization with myelin antigen, their migratory capacity and re-activation within the nervous tissue were either only mildly affected or remained unchanged. Instead, laquinimod directly impacted the functionality of the CNS vasculature. The expression of tight junction proteins p120 and ZO-1 in human brain endothelial cells was up-regulated upon laquinimod treatment, resulting in a significant increase in the transendothelial electrical resistance of confluent monolayers of brain endothelial cells. Similarly, expression of the adhesion molecule activated leukocyte cell adhesion molecule (ALCAM) and inflammatory chemokines CCL2 and IP-10 was suppressed, leading to a significant reduction in the migration of memory T_H1 and T_H17 lymphocytes across the blood brain barrier (BBB). Our data indicate that laquinimod exerts its therapeutic effects by tightening the BBB and limiting parenchymal invasion of effector T cells, thereby reducing CNS damage.

Laquinimod Safety Profile: Pooled Analyses from the ALLEGRO and BRAVO Trials

BACKGROUND

Laquinimod 0.6 mg is a once-daily, oral, disease-modifying therapy in development for the treatment of multiple sclerosis (MS) that was investigated in two double-blind, placebo-controlled, phase 3 trials: ALLEGRO and BRAVO.

METHODS

Data from these studies were pooled to assess the safety profile of laquinimod versus placebo. Adverse events (AEs), laboratory value changes, and potential risks identified in preclinical studies were evaluated in participants in ALLEGRO and BRAVO treated with at least one dose of laquinimod or matching placebo (1:1 random assignment).

RESULTS

In total, 1988 patients received at least one dose of study drug (laquinimod: n = 983 [mean ± SD duration, 639 ± 190 days]; placebo: n = 1005 [mean ± SD duration, 627 ± 198 days]). Early terminations due to AEs were infrequent (laquinimod: 6.4%; placebo: 4.7%). Death was reported in four patients (laquinimod: n = 1; placebo: n = 3). Rates of serious AEs (including malignancies, infections, and cardiovascular AEs) were similar between groups. The most common AEs identified with laquinimod use were back and neck pain and appendicitis. Laquinimod was also associated with asymptomatic changes in liver enzyme levels, fibrinogen levels, and hematologic parameters that followed a consistent temporal pattern: mild, nonprogressive, and occurring within 90 days of treatment initiation, then stabilizing or reverting to baseline levels during continued treatment.

CONCLUSIONS

Data from these pivotal laquinimod studies demonstrate a safety profile comprising benign or manageable AEs and asymptomatic laboratory findings with a clear temporal pattern. Potential risks noted in preclinical studies were not observed.

Treatment of spontaneous EAE by laquinimod reduces Tfh, B cell aggregates, and disease progression

Objective:

To evaluate the influence of oral laquinimod, a candidate multiple sclerosis (MS) treatment, on induction of T follicular helper cells, development of meningeal B cell aggregates, and clinical disease in a spontaneous B cell–dependent MS model.

Methods:

Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice by immunization with recombinant myelin oligodendrocyte glycoprotein (rMOG) protein. Spontaneous EAE was evaluated in C57BL/6 MOG p35-55–specific T cell receptor transgenic (2D2) × MOG-specific immunoglobulin (Ig)H-chain knock-in (IgH^MOG-ki [Th]) mice. Laquinimod was administered orally. T cell and B cell populations were examined by flow cytometry and immunohistochemistry.

Results:

Oral laquinimod treatment (1) reduced CD11c⁺CD4⁺ dendritic cells, (2) inhibited expansion of PD-1⁺CXCR5⁺BCL6⁺ T follicular helper and interleukin (IL)-21–producing activated CD4⁺CD44⁺ T cells, (3) suppressed B cell CD40 expression, (4) diminished formation of Fas⁺GL7⁺ germinal center B cells, and (5) inhibited development of MOG-specific IgG. Laquinimod treatment not only prevented rMOG-induced EAE, but also inhibited development of spontaneous EAE and the formation of meningeal B cell aggregates. Disability progression was prevented when laquinimod treatment was initiated after mice developed paralysis. Treatment of spontaneous EAE with laquinimod was also associated with increases in CD4⁺CD25^hiFoxp3⁺ and CD4⁺CD25⁺IL-10⁺ regulatory T cells.

Conclusions:

Our observations that laquinimod modulates myelin antigen–specific B cell immune responses and suppresses both development of meningeal B cell aggregates and disability progression in spontaneous EAE should provide insight regarding the potential application of laquinimod to MS treatment. Results of this investigation demonstrate how the 2D2 × Th spontaneous EAE model can be used successfully for preclinical evaluation of a candidate MS treatment.

Tweaking Mesenchymal Stem/Progenitor Cell Immunomodulatory Properties with Viral Vectors Delivering Cytokines

Mesenchymal Stem Cells (MSCs) can be found in various body sites. Their main role is to differentiate into cartilage, bone, muscle, and fat cells to allow tissue maintenance and repair. During inflammation, MSCs exhibit important immunomodulatory properties that are not constitutive, but require activation, upon which they may exert immunosuppressive functions. MSCs are defined as "sensors of inflammation" since they modulate their ability of interfering with the immune system both in vitro and in vivo upon interaction with different factors. MSCs may influence immune responses through different mechanisms, such as direct cell-to-cell contact, release of soluble factors, and through the induction of anergy and apoptosis. Human MSCs are defined as plastic-adherent cells expressing specific surface molecules. Lack of MHC class II antigens makes them appealing as allogeneic tools for the therapy of both autoimmune diseases and cancer. MSC therapeutic potential could be highly enhanced by the expression of exogenous cytokines provided by transduction with viral vectors. In this review, we attempt to summarize the results of a great number of in vitro and in vivo studies aimed at improving the ability of MSCs as immunomodulators in the therapy of autoimmune, degenerative diseases and cancer. We will also compare results obtained with different vectors to deliver heterologous genes to these cells.

Further understanding of the immunopathology of multiple sclerosis: impact on future treatments

INTRODUCTION

The understanding of the immunopathogenesis of multiple sclerosis (MS) has expanded with more research into T-cell subtypes, cytokine contributors, B-cell participation, mitochondrial dysfunction, and more. Treatment options have rapidly expanded with three relatively recent oral therapy alternatives entering the arena.

AREAS COVERED

In the following review, we discuss current mechanisms of immune dysregulation in MS, how they relate to current treatments, and the impact these findings will have on the future of therapy. Expert commentary: The efficacy of these medications and understanding their mechanisms of actions validates the immunopathogenic mechanisms thought to underlie MS. Further research has exposed new targets, while new promising therapies have shed light on new aspects into the pathophysiology of MS.

Laquinimod dampens hyperactive cytokine production in Huntington's disease patient myeloid cells

Huntington's disease (HD) is a neurodegenerative condition characterized by pathology in the brain and peripheral tissues. Hyperactivity of the innate immune system, due in part to NFκB pathway dysregulation, is an early and active component of HD. Evidence suggests targeting immune disruption may slow disease progression. Laquinimod is an orally active immunomodulator that down-regulates proinflammatory cytokine production in peripheral blood mononuclear cells, and in the brain down-regulates astrocytic and microglial activation by modulating NFκB signalling. Laquinimod had beneficial effects on inflammation, brain atrophy and disease progression in multiple sclerosis (MS) in two phase III clinical trials. This study investigated the effects of laquinimod on hyperactive proinflammatory cytokine release and NFκB signalling in HD patient myeloid cell cultures. Monocytes from manifest (manHD) and pre-manifest (preHD) HD gene carriers and healthy volunteers (HV) were treated with laquinimod and stimulated with lipopolysaccharide. After 24 h pre-treatment with 5 μM laquinimod, manHD monocytes released lower levels of IL-1β, IL-5, IL-8, IL-10, IL-13 and TNFα in response to stimulation. PreHD monocytes released lower levels of IL-8, IL-10 and IL-13, with no reduction observed in HV monocytes. The effects of laquinimod on dysfunctional NFκB signalling in HD was assessed by inhibitor of kappa B (IκB) degradation kinetics, nuclear translocation of NFκB and interactions between IκB kinase (IKK) and HTT, in HD myeloid cells. No differences were observed between laquinimod-treated and untreated conditions. These results provide evidence that laquinimod dampens hyper-reactive cytokine release from manHD and preHD monocytes, with a much reduced effect on HV monocytes. Evidence suggests targeting CNS and peripheral immune disruption may slow Huntington's disease (HD) neurodegenerative processes. The effects of laquinimod, an orally active immunomodulator, on hyperactive cytokine release and dysfunctional NFκB signalling in stimulated myeloid cell cultures from pre-manifest and manifest HD gene carriers and healthy volunteers were investigated. Laquinimod dampened cytokine release but did not impact NFκB signalling. Read the Editorial Highlight for this article on page 670.

Laquinimod prevents cuprizone-induced demyelination independent of Toll-like receptor signaling

Objective:

To test whether Toll-like receptor (TLR) signaling plays a key role for reduced nuclear factor B (NF-κB) activation after laquinimod treatment in the model of cuprizone-induced demyelination, oligodendrocyte apoptosis, inflammation, and axonal damage.

Methods:

Ten-week-old C57BL/6J, TLR4^−/−, and MyD88^−/− mice received 0.25% cuprizone for 6 weeks and were treated daily with 25 mg/kg laquinimod or vehicle. After 6 weeks of demyelination, extent of demyelination, oligodendrocyte density, microglia infiltration, and axonal damage were analyzed in the corpus callosum. Additionally, we analyzed primary mouse astrocytes from C57BL/6J, TLR4^−/−, MyD88^−/−, and TRIF^−/− mice for alteration in NF-κB signaling.

Results:

Vehicle-treated controls from C57BL/6J, TLR4^−/−, and MyD88^−/− mice displayed extensive callosal demyelination as well as microglial activation. In contrast, mice treated with 25 mg/kg laquinimod showed mainly intact callosal myelin. The demyelination score was significantly higher in all untreated mice compared to mice treated with laquinimod. There were significantly fewer APP-positive axonal spheroids, Mac3-positive macrophages/microglia, and less oligodendrocyte apoptosis in the corpus callosum of laquinimod-treated mice in comparison to untreated controls. Stimulated primary mouse astrocytes from laquinimod-treated groups show reduced NF-κB activation compared to vehicle-treated controls.

Conclusions:

Our results confirm that laquinimod prevents demyelination in the cuprizone mouse model for multiple sclerosis via downregulation of NF-κB activation. This laquinimod effect, however, does not involve upstream Toll-like receptor signaling.

Will novel oral formulations change the management of inflammatory bowel disease?

INTRODUCTION

The traditional management of inflammatory bowel disease (IBD) with sulphasalazine/5-aminosalicylic acid, glucocorticoids and immunomodulators (i.e., thiopurines and methotrexate) was nearly two decades ago extended with intravenously or subcutaneously administered biologics (i.e., tumor necrosis factor inhibitors and later gut-selective integrin antagonists). However, recently, orally administered treatments with simple, well-characterized, and stable structures consisting of either small molecules or anti-sense therapy have been devised.

AREAS COVERED

This review discusses the current approaches with promising new oral drugs with distinct modes of action, including: the Janus kinase inhibitors (i.e., tofacitinib, filgotinib and peficitinib); the immunomodulatory drug (laquinimod); a small α4 antagonist (AJM300); agonists for sphingosine-phosphate receptors (i.e., ozanimod, APD334, and amiselimod), as well as anti-sense therapy (mongersen) targeting SMAD7, drugs which directly target intracellular pathways of relevance for intestinal inflammation.

EXPERT OPINION

A new avenue using easily administered oral therapies for the management of IBD is being introduced. While their place in the clinical armamentarium remains to be proven, it is likely that many of these drugs will find their place in the treatment algorithm of IBD in the next few years. Thus, we will face times in which IBD therapy will be based on significantly more tablets than prescribed today.

Current stage in inflammatory bowel disease: What is next?

In recent years, the incidence of inflammatory bowel disease (IBD) has been on the rise, extending to countries where it was infrequent in the past. As a result, the gap between high and low incidence countries is decreasing. The disease, therefore, has an important economic impact on the healthcare system. Advances in recent years in pharmacogenetics and clinical pharmacology have allowed for the development of treatment strategies adjusted to the patient profile. Concurrently, new drugs aimed at inflammatory targets have been developed that may expand future treatment options. This review examines advances in the optimization of existing drug treatments and the development of novel treatment options for IBD.

A phase II study of laquinimod in Crohn's disease

OBJECTIVE

Laquinimod is an oral therapeutic agent under investigation for the treatment of Crohn's disease (CD), Huntington's disease, lupus nephritis and multiple sclerosis. This dose escalation study evaluated the safety and efficacy of laquinimod as induction therapy in patients with active moderate-severe CD.

DESIGN

Multicentre, double-blind, sequential-cohort, randomised controlled trial with laquinimod doses of 0.5, 1, 1.5 or 2 mg/day or placebo (n=45 per cohort randomised in a 2:1 ratio) for 8 weeks with 4-week follow-up. Stable concomittant therapies and prior use of anti-tumour necrosis factor agents were permitted. Comprehensive safety assessments were performed and efficacy analyses included the proportions of patients in clinical remission (CD Activity Index (CDAI) <150 and no treatment failure (TF)), and with a clinical response (70 or 100 point CDAI reduction from baseline or remission and no TF).

RESULTS

117 patients received laquinimod and 63 patients received placebo. The overall incidence of adverse events (AEs) in the laquinimod group was similar to the pooled placebo group (86.2%-96.7% vs 82.5%) and most AEs were mild to moderate in severity. Treatment with laquinimod 0.5 mg showed consistent effects on remission (48.3% (CI 31% to 66%) vs 15.9% (CI 9% to 27%)), response 100 (55.2% (CI 37% to 71%) vs 31.7% (CI 22% to 44%)) and response 70 (62.1% (CI 44% to 77%) vs 34.9% (CI 24% to 47%)) versus placebo. Laquinimod 1.0 mg showed less benefit (26.7% remission (CI 14% to 44%) and 53.3% response 70 (CI 36% to 70%)), and no effect was noted on remission/response at higher doses.

CONCLUSIONS

Laquinimod was safe and well tolerated, and the effects on remission and response of the 0.5 mg dose suggest a treatment benefit in patients with CD.

TRIAL REGISTRATION NUMBER

NCT00737932.

The role of laquinimod in modulation of the immune response in relapsing-remitting multiple sclerosis: Lessons from gene expression signatures

Laquinimod, is a potential oral immunomodulatory drug, for relapsing-remitting multiple sclerosis (RRMS). We analyzed the blood-transcriptional changes in RRMS patients (who participated in the ALLEGRO clinical trial) at one and six months after laquinimod treatment using gene expression microarrays. The molecular effects of laquinimod were enhanced by duration of treatment and showed down-regulation of inflammatory responses mainly via TGFb signaling, and of pro-inflammatory cytokines as well as of cellular movement, including adhesion, migration and leukocyte extravasation signaling. Our results demonstrate that laquinimod suppresses inflammation through down-regulation of inflammatory cytokines and arrest of leukocyte extravasation and thereby could attenuate disease activity in RRMS patients.

Immune parameters of patients treated with laquinimod, a novel oral therapy for the treatment of multiple sclerosis: results from a double-blind placebo-controlled study

Laquinimod is a novel orally administered drug for the treatment of relapsing remitting multiple sclerosis (RRMS). In this immunological substudy of the phase III Assessment of Oral Laquinimod in Preventing Progression of MS (ALLEGRO) trial, we performed an ex vivo and in vitro analysis of effects exerted by laquinimod on peripheral blood immune cell populations from RRMS patients with a special focus on monocyte phenotype and function. Approximately 100 patients were enrolled following a standardized protocol. Half of the patients received laquinimod and the other half received placebo. Peripheral blood samples were collected prior to commencement of therapy and after 1, 3, 6, 12, and 24 months of continuous therapy. Main lymphocytic and antigen presenting cell fractions were analyzed in peripheral blood mononuclear cells (PBMCs) ex vivo by flow cytometry. The proliferative response of PBMCs to mitogen or recall antigen was assessed in culture experiments. Untouched monocytes were sorted magnetically and cultured under pro-inflammatory conditions. PBMC analysis showed no significant differences of investigated lymphocytic and antigen presenting cell populations over time within each group, or between the two groups. However, the detailed in vitro analysis of monocytes demonstrated a lower level of CD86 expression on monocytes stimulated with LPS in laquinimod patients beginning from the 1st month of treatment. Upon pro-inflammatory stimulation, monocytes obtained from laquinimod treated patients tended to secrete lower levels of the proinflammatory chemokines CCL2 or CCL5. Taken together, in this prospective study, we demonstrate immune modulation but no immunosuppressive biological activity of laquinimod in a large group of MS patients.

Oral disease-modifying therapies for multiple sclerosis

Classical multiple sclerosis (MS) treatments using first-line injectable drugs, although widely applied, remain a major concern in terms of therapeutic adherence and efficacy. New oral drugs recently approved for MS treatment represent significant advances in therapy. The oral route of administration clearly promotes patient satisfaction and increases therapeutic compliance. However, these drugs may also have safety and tolerability issues, and a thorough analysis of the risks and benefits is required. Three oral drugs have been approved by regulatory agencies for MS treatment: fingolimod, teriflunomide, and dimethyl fumarate. This article reviews the mechanisms of action, safety, and efficacy of these drugs and two other drugs that have yielded positive results in phase III trials: cladribine and laquinimod.

Neurobehavioral burden of multiple sclerosis with nanotheranostics

Multiple sclerosis (MS) is a chronic demyelinating neurological disorder affecting people worldwide; women are affected more than men. MS results in serious neurological deficits along with behavioral compromise, the mechanisms of which still remain unclear. Behavioral disturbances such as depression, anxiety, cognitive impairment, psychosis, euphoria, sleep disturbances, and fatigue affect the quality of life in MS patients. Among these, depression and psychosis are more common than any other neurological disorders. In addition, depression is associated with other comorbidities. Although anxiety is often misdiagnosed in MS patients, it can induce suicidal ideation if it coexists with depression. An interrelation between sleep abnormalities and fatigue is also reported among MS patients. In addition, therapeutics for MS is always a challenge because of the presence of the blood-brain barrier, adding to the lack of detailed understanding of the disease pathology. In this review, we tried to summarize various behavioral pathologies and their association with MS, followed by its conventional treatment and nanotheranostics.

Relationship between T-lymphocyte subsets in peripheral blood and acute rejection after liver transplantation in rats

AIM: To investigate the changes of CD4⁺/CD8⁺ T-lymphocyte subsets in peripheral blood in rats after liver transplantation, and to evaluate their effect on acute rejection.

METHODS: Inbred DA and Lewis rats were randomly divided into three groups: a liver isograft group (group I: Lewis → Lewis, n = 12), a liver allograft group (A group: DA → Lewis, n = 12), and a sham-operated group (group C: Lewis rats, n = 12). Modified "two-cuff technique" was used to perform rat orthotopic liver transplantation. Survival rates at 1 and 2 wk were computed. Histological changes of graft and the changes of CD4⁺/CD8⁺ T-lymphocyte subsets in peripheral blood after transplantation were examined by HE staining and flow cytometry, respectively.

RESULTS: One-week survival rates in group I and group A were 100% and 41.7%, respectively. Two-week survival rates were 75% and 8.3%, respectively (P < 0.05). Group A showed severe acute graft rejection 7 d after transplantation, but this did not occur in group I. The percentage of CD4⁺ T cells was significantly higher in group A than in group I and group C (P < 0.05). The percentage of CD8⁺ T cells was significantly lower in group I than in group A (P < 0.05). The ratio of CD4⁺/CD8⁺ T cells was significantly higher in group A than in group I and group C (P < 0.05). Serum levels of interferon-γ (IFN-γ) were markedly increased in group A, but decreased in groups I and C, while interleukin-10 (IL-10) showed an opposite trend.

CONCLUSION: The changes of CD4⁺/CD8⁺ T-lymphocyte subsets in peripheral blood are closely related to rejection and tolerance after rat liver transplantation. CD4⁺ T cell proliferative activity and the ratio of CD4⁺/CD8⁺ T cells induce acute rejection, and CD8⁺ T cell reduction may be one of the mechanisms of immune tolerance.

Multiple sclerosis: overview of disease-modifying agents

Multiple sclerosis (MS) is a chronic autoimmune disease that usually affects young adults, causing progressive physical and cognitive disability. Since the 1990s, its treatment has been based on parenteral medications known collectively as immunomodulators. This drug class is considered safe and usually prevents 30% of MS relapses. Drugs in this class exert almost the same efficacy and require an inconvenient administration route. New medications have recently been launched worldwide. Thus, new oral drugs are increasingly being administered to MS patients and contributing to a better quality of life, since these have better efficacy than the old immunomodulators. Today, 10 different drugs for MS are marketed worldwide, which requires deep knowledge among neurologists and other healthcare professionals. This paper summarizes all the drugs approved for MS in the US and Europe, emphasizing their mechanism of action, the results from phase II and III studies, and the product safety.

Future treatment approaches to multiple sclerosis

The modern treatment era for multiple sclerosis (MS) began in 1993 with the approval of the first disease-modifying agent. Since then the field has greatly expanded, with 10 therapies currently approved to treat MS. These treatments are effective to reduce relapses and changes on MRI, and slow disability. However, despite these medications some patients continue to have exacerbations, accumulate disability, and develop progressive disease due to partial effectiveness. New molecules with novel mechanisms of action and targets are being explored. Hopefully these agents will yield even greater efficacy without significant safety concerns. As more aggressive therapies are available to treat MS, the goals and expectations of treatment are also likely to change. Some of the emerging therapies, including alemtuzumab, daclizumab, rituximab, ocrelizumab, laquinimod, estriol, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins), vitamin D, and stem cell transplantation, will be discussed in this chapter. In the future, therapies with different mechanisms may be combined, but this will need to be evaluated in clinical trials. Neuroprotection and repair definitely warrant further study. The future of MS treatment is very exciting, especially as our armamentarium expands.

In vitro assessment of the direct effect of laquinimod on basic functions of human neural stem cells and oligodendrocyte progenitor cells

Laquinimod is an orally active immunomodulatory small molecule that has shown clear clinical benefit in trials for relapsing-remitting multiple sclerosis and in experimental rodent models that emulate multiple sclerosis (MS). Studies in healthy mice, and in mice with experimental autoimmune encephalomyelitis, have demonstrated that laquinimod is capable of entering the central nervous system. It is therefore important to determine if laquinimod is capable of a direct influence on basic functions of neural stem cells (NSC) or oligodendrocyte progenitor cells (OPC)--cells critical for myelin repair in MS. In order to address this question, a series of experiments was conducted to determine the effect of exogenous laquinimod on viability, proliferation, migration and differentiation of human NSC and OPC in vitro. These data show, for the first time in cells of human origin, that direct, short-term interaction between laquinimod and NSC or OPC, in an isolated in vitro setting, is not detrimental to the basic cellular function of these cells.

Laquinimod reduces neuroaxonal injury through inhibiting microglial activation

OBJECTIVE

Laquinimod is an emerging oral medication for multiple sclerosis (MS) that reduces brain atrophy and progression of disability in two Phase III clinical trials. The mechanism of these effects is unclear. Persistent activation of microglia occurs in MS and contributes to injury. Thus, we investigated whether laquinimod alters properties of microglia in culture and in experimental autoimmune encephalomyelitis (EAE), and whether this reduces neurodegeneration.

METHODS

Microglia were cultured from human brains. EAE was induced in mice.

RESULTS

The activation of human microglia increased levels of several pro- and anti-inflammatory cytokines and these elevations were attenuated by pretreatment with laquinimod. Laquinimod prevented the decline in activated microglia of miR124a, a microRNA implicated in maintaining microglia quiescence, and reduced the activity of several signaling pathways (Jun-N-terminal kinase, ribosomal S6 kinase, and AKT/protein kinase B) in activated microglia. In EAE, axonal injury correlated with accumulation of microglia/macrophages in the spinal cord. EAE mice treated with laquinimod before onset of clinical signs subsequently had reduced microglia/macrophage density and axonal injury. Remarkably, when laquinimod treatment was initiated well into the disease course, the progressive demyelination, and axonal loss was halted. Besides inflammatory molecules associated with microglia, the level of inducible nitric oxide (NO) synthase capable of producing free radical toxicity was attenuated by laquinimod in EAE mice. Finally, in coculture where microglia activation caused neuronal death, laquinimod decreased NO levels, and neurotoxicity.

INTERPRETATION

Laquinimod is a novel inhibitor of microglial activation that lowers microglia-induced neuronal death in culture and axonal injury/loss in EAE.

Laquinimod therapy in multiple sclerosis: a comprehensive review

Introduction

Multiple sclerosis (MS) is considered an autoimmune disease with inflammatory and neurodegenerative underlying processes that affect the central nervous system. The available disease-modifying therapies (DMTs) approved to treat MS have only shown partial benefit in controlling the disease progression, primarily impeding its inflammatory component, while the parenteral administration of most of these therapies has shown to affect patient compliance. Laquinimod is a promising new oral drug recently evaluated in a third phase III clinical trial that demonstrated beneficial effects in delaying disease progression and preventing brain atrophy, suggesting a potential neuroprotective effect and a favorable safety profile.

Areas Covered

This is a comprehensive review covering clinical efficacy and safety data obtained from two phase III clinical trials, as well as the presumed beneficial mechanism of action, of laquinimod. This article also provides a short overview of the oral DMTs recently approved for the treatment of relapsing MS, as well as challenges that still remain to be overcome to fully control the relentless course of MS.

Conclusion

Laquinimod has been shown to have a novel immunomodulatory and potential neuroprotective mechanism of action as suggested from animal models and in vitro experimental data. Phase III clinical trials ALLEGRO (Clinicaltrials.gov #NCT00509145) and BRAVO (Clinicaltrials.gov #NCT00605215) have demonstrated clinical efficacy and tolerability, while the third phase III study is currently evaluating the safety and efficacy of laquinimod at a higher dosage. Emerging oral treatments like laquinimod will provide new options for patients to consider that can lead to better patient adherence and improved outcomes.

Electronic supplementary material

The online version of this article (doi:10.1007/s40120-014-0017-6) contains supplementary material, which is available to authorized users.