Inhibition of experimental autoimmune encephalomyelitis by a novel small molecular weight proinflammatory cytokine suppressing drug

Therapeutic treatment with the anti-inflammatory drug candidate MW151 may partially reduce memory impairment and normalizes hippocampal metabolic markers in a mouse model of comorbid amyloid and vascular pathology

Alzheimer’s disease (AD) is the leading cause of dementia in the elderly, but therapeutic options are lacking. Despite long being able to effectively treat the ill-effects of pathology present in various rodent models of AD, translation of these strategies to the clinic has so far been disappointing. One potential contributor to this situation is the fact that the vast majority of AD patients have other dementia-contributing comorbid pathologies, the most common of which are vascular in nature. This situation is modeled relatively infrequently in basic AD research, and almost never in preclinical studies. As part of our efforts to develop small molecule, anti-inflammatory therapeutics for neurological injury and disease, we have recently been exploring potentially promising treatments in preclinical multi-morbidity contexts. In the present study, we generated a mouse model of mixed amyloid and hyperhomocysteinemia (HHcy) pathology in which to test the efficacy of one of our anti-inflammatory compounds, MW151. HHcy can cause cerebrovascular damage and is an independent risk factor for both AD dementia and vascular contributions to cognitive impairment and dementia. We found that MW151 was able to partially rescue hippocampal-dependent spatial memory and learning deficits in this comorbidity context, and further, that the benefit is associated with a normalization of hippocampal metabolites detectable via magnetic resonance spectroscopy. These findings provide evidence that MW151 in particular, and potentially anti-inflammatory treatment more generally, may be beneficial in AD patients with comorbid vascular pathology.

A comprehensive review on the role of chemokines in the pathogenesis of multiple sclerosis

Multiple sclerosis (MS) as a chronic inflammatory disorder of the central nervous system (CNS) is thought to be caused by the abnormal induction of immune responses. Chemokines as molecules that can engage leukocytes into the location of inflammation, actively participate in the pathogenesis of MS. Several members of this family of chemo attractants have been shown to be dysregulated in the peripheral blood, cerebrospinal fluid or CNS lesions of MS patients. Studies in animal models of MS particularly experimental autoimmune encephalomyelitis have indicated the critical roles of chemokines in the pathophysiology of MS. In the current review, we summarize the data regarding the role of CCL2, CCL3, CCL4, CCL11, CCL20, CXCL1, CXCL2, CXCL8, CXCL10, CXCL12 and CXCL13 in the pathogenesis of MS.

The regulation and importance of monocyte chemoattractant protein-1

PURPOSE OF REVIEW

Monocyte chemoattractant protein (MCP)-1, a chemokine regulating monocyte chemotaxis and T-lymphocyte differentiation by binding to the CC chemokine receptor 2 (CCR2), plays a crucial role in the pathogenesis of inflammatory diseases, atherosclerosis and cancer. This review summarizes the current knowledge on the regulation and importance of the MCP-1/CCR2 axis, focusing on the therapeutic potential of its inhibition.

RECENT FINDINGS

Differential modulation of MCP-1 and CCR2 lead to downstream activation pathways, pathogenetic to differing disease conditions characterized by dysregulated monocyte/macrophage tissue recruitment. Pharmacological targeting of the MCP-1/CCR2 axis has led to selective MCP-1/CCR2 antagonists that have now entered phase I/II clinical trials for the treatment of inflammatory diseases, atherosclerosis and cancer. The pleiotropic nonselective MCP-1/CCR2 inhibition by current pharmacological agents is thought to contribute to their anti-inflammatory and antiatherosclerotic effects that is also seen for nutraceutical compounds such as curcumin.

SUMMARY

MCP-1 has a critical role in regulating chemotaxis both in health and disease, with increasing interest in its pharmacological inhibition. However, the therapeutic efficacy and safety of targeting the MCP-1/CCR2 axis is still in evolution.

MW151 Inhibited IL-1β Levels after Traumatic Brain Injury with No Effect on Microglia Physiological Responses

A prevailing neuroinflammation hypothesis is that increased production of proinflammatory cytokines contributes to progressive neuropathology, secondary to the primary damage caused by a traumatic brain injury (TBI). In support of the hypothesis, post-injury interventions that inhibit the proinflammatory cytokine surge can attenuate the progressive pathology. However, other post-injury neuroinflammatory responses are key to endogenous recovery responses. Therefore, it is critical that pharmacological attenuation of detrimental or dysregulated neuroinflammatory processes avoid pan-suppression of inflammation. MW151 is a CNS-penetrant, small molecule experimental therapeutic that restores injury- or disease-induced overproduction of proinflammatory cytokines towards homeostasis without immunosuppression. Post-injury administration of MW151 in a closed head injury model of mild TBI suppressed acute cytokine up-regulation and downstream cognitive impairment. Here, we report results from a diffuse brain injury model in mice using midline fluid percussion. Low dose (0.5–5.0 mg/kg) administration of MW151 suppresses interleukin-1 beta (IL-1β) levels in the cortex while sparing reactive microglia and astrocyte responses. To probe molecular mechanisms, we used live cell imaging of the BV-2 microglia cell line to demonstrate that MW151 does not affect proliferation, migration, or phagocytosis of the cells. Our results provide insight into the roles of glial responses to brain injury and indicate the feasibility of using appropriate dosing for selective therapeutic modulation of injurious IL-1β increases while sparing other glial responses to injury.

Closed head injury in an age-related Alzheimer mouse model leads to an altered neuroinflammatory response and persistent cognitive impairment

Epidemiological studies have associated increased risk of Alzheimer's disease (AD)-related clinical symptoms with a medical history of head injury. Currently, little is known about pathophysiology mechanisms linked to this association. Persistent neuroinflammation is one outcome observed in patients after a single head injury. Neuroinflammation is also present early in relevant brain regions during AD pathology progression. In addition, previous mechanistic studies in animal models link neuroinflammation as a contributor to neuropathology and cognitive impairment in traumatic brain injury (TBI) or AD-related models. Therefore, we explored the potential interplay of neuroinflammatory responses in TBI and AD by analysis of the temporal neuroinflammatory changes after TBI in an AD model, the APP/PS1 knock-in (KI) mouse. Discrete temporal aspects of astrocyte, cytokine, and chemokine responses in the injured KI mice were delayed compared with the injured wild-type mice, with a peak neuroinflammatory response in the injured KI mice occurring at 7 d after injury. The neuroinflammatory responses were more persistent in the injured KI mice, leading to a chronic neuroinflammation. At late time points after injury, KI mice exhibited a significant impairment in radial arm water maze performance compared with sham KI mice or injured wild-type mice. Intervention with a small-molecule experimental therapeutic (MW151) that selectively attenuates proinflammatory cytokine production yielded improved cognitive behavior outcomes, consistent with a link between neuroinflammatory responses and altered risk for AD-associated pathology changes with head injury.

Attenuation of traumatic brain injury-induced cognitive impairment in mice by targeting increased cytokine levels with a small molecule experimental therapeutic

Background

Evidence from clinical studies and preclinical animal models suggests that proinflammatory cytokine overproduction is a potential driving force for pathology progression in traumatic brain injury (TBI). This raises the possibility that selective targeting of the overactive cytokine response, a component of the neuroinflammation that contributes to neuronal dysfunction, may be a useful therapeutic approach. MW151 is a CNS-penetrant, small molecule experimental therapeutic that selectively restores injury- or disease-induced overproduction of proinflammatory cytokines towards homeostasis. We previously reported that MW151 administered post-injury (p.i.) is efficacious in a closed head injury (CHI) model of diffuse TBI in mice. Here we test dose dependence of MW151 to suppress the target mechanism (proinflammatory cytokine up-regulation), and explore the therapeutic window for MW151 efficacy.

Methods

We examined suppression of the acute cytokine surge when MW151 was administered at different times post-injury and the dose-dependence of cytokine suppression. We also tested a more prolonged treatment with MW151 over the first 7 days post-injury and measured the effects on cognitive impairment and glial activation.

Results

MW151 administered up to 6 h post-injury suppressed the acute cytokine surge, in a dose-dependent manner. Administration of MW151 over the first 7 days post-injury rescues the CHI-induced cognitive impairment and reduces glial activation in the focus area of the CHI.

Conclusions

Our results identify a clinically relevant time window post-CHI during which MW151 effectively restores cytokine production back towards normal, with a resultant attenuation of downstream cognitive impairment.

An anti-neuroinflammatory that targets dysregulated glia enhances the efficacy of CNS-directed gene therapy in murine infantile neuronal ceroid lipofuscinosis

Infantile neuronal ceroid lipofuscinosis (INCL) is an inherited neurodegenerative lysosomal storage disease (LSD) caused by a deficiency in palmitoyl protein thioesterase-1 (PPT1). Studies in Ppt1(-/-) mice demonstrate that glial activation is central to the pathogenesis of INCL. Astrocyte activation precedes neuronal loss, while cytokine upregulation associated with microglial reactivity occurs before and concurrent with neurodegeneration. Therefore, we hypothesized that cytokine cascades associated with neuroinflammation are important therapeutic targets for the treatment of INCL. MW01-2-151SRM (MW151) is a blood-brain barrier penetrant, small-molecule anti-neuroinflammatory that attenuates glial cytokine upregulation in models of neuroinflammation such as traumatic brain injury, Alzheimer's disease, and kainic acid toxicity. Thus, we used MW151, alone and in combination with CNS-directed, AAV-mediated gene therapy, as a possible treatment for INCL. MW151 alone decreased seizure susceptibility. When combined with AAV-mediated gene therapy, treated INCL mice had increased life spans, improved motor performance, and eradication of seizures. Combination-treated INCL mice also had decreased brain atrophy, astrocytosis, and microglial activation, as well as intermediary effects on cytokine upregulation. These data suggest that MW151 can attenuate seizure susceptibility but is most effective when used in conjunction with a therapy that targets the primary genetic defect.

Early stage drug treatment that normalizes proinflammatory cytokine production attenuates synaptic dysfunction in a mouse model that exhibits age-dependent progression of Alzheimer's disease-related pathology

Overproduction of proinflammatory cytokines in the CNS has been implicated as a key contributor to pathophysiology progression in Alzheimer's disease (AD), and extensive studies with animal models have shown that selective suppression of excessive glial proinflammatory cytokines can improve neurologic outcomes. The prior art, therefore, raises the logical postulation that intervention with drugs targeting dysregulated glial proinflammatory cytokine production might be effective disease-modifying therapeutics if used in the appropriate biological time window. To test the hypothesis that early stage intervention with such drugs might be therapeutically beneficial, we examined the impact of intervention with MW01-2-151SRM (MW-151), an experimental therapeutic that selectively attenuates proinflammatory cytokine production at low doses. MW-151 was tested in an APP/PS1 knock-in mouse model that exhibits increases in AD-relevant pathology progression with age, including increases in proinflammatory cytokine levels. Drug was administered during two distinct but overlapping therapeutic time windows of early stage pathology development. MW-151 treatment attenuated the increase in microglial and astrocyte activation and proinflammatory cytokine production in the cortex and yielded improvement in neurologic outcomes, such as protection against synaptic protein loss and synaptic plasticity impairment. The results also demonstrate that the therapeutic time window is an important consideration in efficacy studies of drugs that modulate glia biological responses involved in pathology progression and suggest that such paradigms should be considered in the development of new therapeutic regimens that seek to delay the onset or slow the progression of AD.

The CCL2 synthesis inhibitor bindarit targets cells of the neurovascular unit, and suppresses experimental autoimmune encephalomyelitis

BACKGROUND

Production of the chemokine CCL2 by cells of the neurovascular unit (NVU) drives critical aspects of neuroinflammation. Suppression of CCL2 therefore holds promise in treating neuroinflammatory disease. Accordingly, we sought to determine if the compound bindarit, which inhibits CCL2 synthesis, could repress the three NVU sources of CCL2 most commonly reported in neuroinflammation--astrocytes, microglia and brain microvascular endothelial cells (BMEC)--as well as modify the clinical course of neuroinflammatory disease.

METHODS

The effect of bindarit on CCL2 expression by cultured murine astrocytes, microglia and BMEC was examined by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Bindarit action on mouse brain and spinal cord in vivo was similarly investigated by qRT-PCR following LPS injection in mice. And to further gauge the potential remedial effects of bindarit on neuroinflammatory disease, its impact on the clinical course of experimental autoimmune encephalomyelitis (EAE) in mice was also explored.

RESULTS

Bindarit repressed CCL2 expression by all three cultured cells, and antagonized upregulated expression of CCL2 in both brain and spinal cord in vivo following LPS administration. Bindarit also significantly modified the course and severity of clinical EAE, diminished the incidence and onset of disease, and evidenced signs of disease reversal.

CONCLUSION

Bindarit was effective in suppressing CCL2 expression by cultured NVU cells as well as brain and spinal cord tissue in vivo. It further modulated the course of clinical EAE in both preventative and therapeutic ways. Collectively, these results suggest that bindarit might prove an effective treatment for neuroinflammatory disease.

Animal models of multiple sclerosis--potentials and limitations

Experimental autoimmune encephalomyelitis (EAE) is still the most widely accepted animal model of multiple sclerosis (MS). Different types of EAE have been developed in order to investigate pathogenetic, clinical and therapeutic aspects of the heterogenic human disease. Generally, investigations in EAE are more suitable for the analysis of immunogenetic elements (major histocompatibility complex restriction and candidate risk genes) and for the study of histopathological features (inflammation, demyelination and degeneration) of the disease than for screening of new treatments. Recent studies in new EAE models, especially in transgenic ones, have in connection with new analytical techniques such as microarray assays provided a deeper insight into the pathogenic cellular and molecular mechanisms of EAE and potentially of MS. For example, it was possible to better delineate the role of soluble pro-inflammatory (tumor necrosis factor-α, interferon-γ and interleukins 1, 12 and 23), anti-inflammatory (transforming growth factor-β and interleukins 4, 10, 27 and 35) and neurotrophic factors (ciliary neurotrophic factor and brain-derived neurotrophic factor). Also, the regulatory and effector functions of distinct immune cell subpopulations such as CD4+ Th1, Th2, Th3 and Th17 cells, CD4+FoxP3+ Treg cells, CD8+ Tc1 and Tc2, B cells and γδ+ T cells have been disclosed in more detail. The new insights may help to identify novel targets for the treatment of MS. However, translation of the experimental results into the clinical practice requires prudence and great caution.

Enhanced microglial activation and proinflammatory cytokine upregulation are linked to increased susceptibility to seizures and neurologic injury in a 'two-hit' seizure model

Early-life seizures result in increased susceptibility to seizures and greater neurologic injury with a second insult in adulthood. The mechanisms which link seizures in early-life to increased susceptibility to neurologic injury following a 'second hit' are not known. We examined the contribution of microglial activation and increased proinflammatory cytokine production to the subsequent increase in susceptibility to neurologic injury using a kainic acid (KA)-induced, established 'two-hit' seizure model in rats. Postnatal day (P)15 rats were administered intraperitoneal KA (early-life seizures) or saline, followed on P45 with either a 'second hit' of KA, a first exposure to KA (adult seizures), or saline. We measured the levels of proinflammatory cytokines (IL-1 beta, TNF-alpha, and S100B), the chemokine CCL2, microglial activation, seizure susceptibility and neuronal outcomes in adult rats 12 h and 10 days after the second hit on P45. The 'two-hit' group exposed to KA on both P15 and P45 had higher levels of cytokines, greater microglial activation, and increased susceptibility to seizures and neurologic injury compared to the adult seizures group. Treatment after early-life seizures with Minozac, a small molecule experimental therapeutic that targets upregulated proinflammatory cytokine production, attenuated the enhanced microglial and cytokine responses, the increased susceptibility to seizures, and the greater neuronal injury in the 'two-hit' group. These results implicate microglial activation as one mechanism by which early-life seizures contribute to increased vulnerability to neurologic insults in adulthood, and indicate the potential longer term benefits of early-life intervention with therapies that target up-regulation of proinflammatory cytokines.

Animal models of multiple sclerosis for the development and validation of novel therapies - potential and limitations

Various types of experimental autoimmune encephalomyelitis (EAE) reflect some of the pathogenetic, clinical, and therapeutic features of the different forms of multiple sclerosis (MS), thereby, providing some, albeit limited, insight into the molecular and cellular basis of the human disease. Specific questions of MS therapy including the search for new therapeutic targets and strategies and their validation require investigations in different available EAE models. A survey is given of experimental therapeutic approaches that are currently under study with the most promising examples of monoclonal antibodies, gene therapy, stem cell transplantation and orally applied small molecular weight disease-modifying drugs. Reasons for therapy failure and adverse side-effects of some experimental trials are discussed. Precaution is advised, if results of new experimental approaches are translated into clinical practice.