Immunotherapy for neurological diseases

Patients with multiple sclerosis who develop immunogenicity to interferon-beta have distinct transcriptomic and proteomic signatures prior to treatment which are associated with disease severity

Anti-drug antibodies (ADA) reduce the efficacy of immunotherapies in multiple sclerosis (MS) and are associated with increased disease progression risk. Blood biomarkers predicting immunogenicity to biopharmaceuticals represent an unmet clinical need. Patients with relapsing remitting (RR)MS were recruited before (baseline), three, and 12 (M12) months after commencing interferon-beta treatment. Neutralising ADA-status was determined at M12, and patients were stratified at baseline according to their M12 ADA-status (ADA-positive/ADA-negative). Patients stratified as ADA-positive were characterised by an early dampened response to interferon-beta (prior to serum ADA detection) and distinct proinflammatory transcriptomic/proteomic peripheral blood signatures enriched for 'immune response activation' including phosphoinositide 3-kinase-γ and NFκB-signalling pathways both at baseline and throughout the treatment course, compared to ADA-negative patients. These immunogenicity-associated proinflammatory signatures significantly overlapped with signatures of MS disease severity. Thus, whole blood molecular profiling is a promising tool for prediction of ADA-development in RRMS and could provide insight into mechanisms of immunogenicity.

Natural product/diet-based regulation of macrophage polarization: Implications in treatment of inflammatory-related diseases and cancer

Macrophages are phagocytic cells with important physiological functions, including the digestion of cellular debris, foreign substances, and microbes, as well as tissue development and homeostasis. The tumor microenvironment (TME) shapes the aggressiveness of cancer, and the biological and cellular interactions in this complicated space can determine carcinogenesis. TME can determine the progression, biological behavior, and therapy resistance of human cancers. The macrophages are among the most abundant cells in the TME, and their functions and secretions can determine tumor progression. The education of macrophages to M2 polarization can accelerate cancer progression, and therefore, the re-education and reprogramming of these cells is promising. Moreover, macrophages can cause inflammation in aggravating pathological events, including cardiovascular diseases, diabetes, and neurological disorders. The natural products are pleiotropic and broad-spectrum functional compounds that have been deployed as ideal alternatives to conventional drugs in the treatment of cancer. The biological and cellular interactions in the TME can be regulated by natural products, and for this purpose, they enhance the M1 polarization of macrophages, and in addition to inhibiting proliferation and invasion, they impair the chemoresistance. Moreover, since macrophages and changes in the molecular pathways in these cells can cause inflammation, the natural products impair the pro-inflammatory function of macrophages to prevent the pathogenesis and progression of diseases. Even a reduction in macrophage-mediated inflammation can prevent organ fibrosis. Therefore, natural product-mediated macrophage targeting can alleviate both cancerous and non-cancerous diseases.

A Comprehensive Review on Neuroimmunology: Insights from Multiple Sclerosis to Future Therapeutic Developments

This review delves into neuroimmunology, focusing on its relevance to multiple sclerosis (MS) and potential treatment advancements. Neuroimmunology explores the intricate relationship between the immune system and the central nervous system (CNS). Understanding these mechanisms is vital for grasping the pathophysiology of diseases like MS and for devising innovative treatments. This review introduces foundational neuroimmunology concepts, emphasizing the role of immune cells, cytokines, and blood-brain barrier in CNS stability. It highlights how their dysregulation can contribute to MS and discusses genetic and environmental factors influencing MS susceptibility. Cutting-edge research methods, from omics techniques to advanced imaging, have revolutionized our understanding of MS, offering valuable diagnostic and prognostic tools. This review also touches on the intriguing gut-brain axis, examining how gut microbiota impacts neuroimmunological processes and its potential therapeutic implications. Current MS treatments, from immunomodulatory drugs to disease-modifying therapies, are discussed alongside promising experimental approaches. The potential of personalized medicine, cell-based treatments, and gene therapy in MS management is also explored. In conclusion, this review underscores neuroimmunology's significance in MS research, suggesting that a deeper understanding could pave the way for more tailored and effective treatments for MS and similar conditions. Continued research and collaboration in neuroimmunology are essential for enhancing patient outcomes.

Big versus small: The impact of aggregate size in disease

Protein aggregation results in an array of different size soluble oligomers and larger insoluble fibrils. Insoluble fibrils were originally thought to cause neuronal cell deaths in neurodegenerative diseases due to their prevalence in tissue samples and disease models. Despite recent studies demonstrating the toxicity associated with soluble oligomers, many therapeutic strategies still focus on fibrils or consider all types of aggregates as one group. Oligomers and fibrils require different modeling and therapeutic strategies, targeting the toxic species is crucial for successful study and therapeutic development. Here, we review the role of different-size aggregates in disease, and how factors contributing to aggregation (mutations, metals, post-translational modifications, and lipid interactions) may promote oligomers opposed to fibrils. We review two different computational modeling strategies (molecular dynamics and kinetic modeling) and how they are used to model both oligomers and fibrils. Finally, we outline the current therapeutic strategies targeting aggregating proteins and their strengths and weaknesses for targeting oligomers versus fibrils. Altogether, we aim to highlight the importance of distinguishing the difference between oligomers and fibrils and determining which species is toxic when modeling and creating therapeutics for protein aggregation in disease.

Natural product-based pharmacological studies for neurological disorders

Central nervous system (CNS) disorders and diseases are expected to rise sharply in the coming years, partly because of the world's aging population. Medicines for the treatment of the CNS have not been successfully made. Inadequate knowledge about the brain, pharmacokinetic and dynamic errors in preclinical studies, challenges with clinical trial design, complexity and variety of human brain illnesses, and variations in species are some potential scenarios. Neurodegenerative diseases (NDDs) are multifaceted and lack identifiable etiological components, and the drugs developed to treat them did not meet the requirements of those who anticipated treatments. Therefore, there is a great demand for safe and effective natural therapeutic adjuvants. For the treatment of NDDs and other memory-related problems, many herbal and natural items have been used in the Ayurvedic medical system. Anxiety, depression, Parkinson's, and Alzheimer's diseases (AD), as well as a plethora of other neuropsychiatric disorders, may benefit from the use of plant and food-derived chemicals that have antidepressant or antiepileptic properties. We have summarized the present level of knowledge about natural products based on topological evidence, bioinformatics analysis, and translational research in this review. We have also highlighted some clinical research or investigation that will help us select natural products for the treatment of neurological conditions. In the present review, we have explored the potential efficacy of phytoconstituents against neurological diseases. Various evidence-based studies and extensive recent investigations have been included, which will help pharmacologists reduce the progression of neuronal disease.

Risk of dementia or Parkinson's disease in the presence of Sjögren's syndrome: A systematic review and meta-analysis

Objective

Evidence from observational studies suggests that Sjögren's syndrome (SS) may contribute to an elevated risk of Parkinson's disease (PD) and dementia. However, few studies have been undertaken to summarize and assess the consistency of the data quantitatively. Therefore, we evaluated the risk of dementia and PD in SS patients through a systematic review and meta-analysis approach.

Methods

Two reviewers independently conducted a systematic search of PubMed, Embase, and Web of Science databases (updated to February 14, 2022) to identify published literature on the association between SS and dementia or PD. The risk estimates of dementia or PD in patients with SS were pooled using fixed or random-effects models.

Results

Of the 631 studies initially searched, 10 were eventually included. Pooled results suggested that the risk of developing dementia significantly increased in patients with SS (HR = 1.24, 95% CI: 1.15-1.33, P < 0.001), and such risk in females with SS was similar to that in males. The risk of PD was 1.36 times higher in SS (HR = 1.36, 95% CI: 1.23-1.50, P < 0.001). The association between SS and PD risk appeared to occur primarily in female patients (female: HR = 1.28, 95% CI: 1.21-1.35; P < 0.001 vs. male: HR = 1.00, 95% CI: 0.87-1.16, P = 0.962, respectively). No significant effect of age was observed on the risk of developing PD and dementia in SS patients.

Conclusion

Our study supports that people with SS are at higher risk of PD and dementia than the general population. Further studies are needed to elucidate the underlying mechanisms and to assess whether interventions for SS have the potential to affect dementia and PD development.

Cancer and Parkinson's Disease: Common Targets, Emerging Hopes

Cancer and neurodegeneration are two major leading causes of morbidity and death worldwide. At first sight, the two fields do not seem to share much in common and, if anything, might be placed on opposite ends of a spectrum. Although neurodegeneration results in excessive neuronal cell death, cancer emerges from increased proliferation and resistance to cell death. Therefore, one might expect significant differences in the underlying pathophysiological mechanisms. However, the more we deepen our understanding of these two types of diseases, the more we appreciate the unexpected overlap between them. Although most epidemiological studies support an inverse association between the risk for development of neurodegenerative diseases and cancer, increasing evidence points to a positive correlation between specific types of cancer, like melanoma, and neurodegenerative diseases, like Parkinson's disease (PD). We believe that deciphering the molecular processes and pathways underlying one of these diseases may significantly increase our understanding about the other. Therefore, the identification of novel biomarkers and therapeutic approaches in cancer, may lead to improved diagnosis and treatment of neurodegeneration, and vice versa. In this Viewpoint, we summarize recent findings connecting both diseases and speculate that insights from one disease may inform on mechanisms, and help identify novel biomarkers and targets for intervention, possibly leading to improved management of both diseases. © 2020 International Parkinson and Movement Disorder Society.

Vasoactive Intestinal Peptide Decreases β-Amyloid Accumulation and Prevents Brain Atrophy in the 5xFAD Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by extracellular deposits of fibrillary β-amyloid (Aβ) plaques in the brain that initiate an inflammatory process resulting in neurodegeneration. The neuronal loss associated with AD results in gross atrophy of affected regions causing a progressive loss of cognitive ability and memory function, ultimately leading to dementia. Growing evidence suggests that vasoactive intestinal peptide (VIP) could be beneficial for various neurodegenerative diseases, including AD. The study investigated the effects of VIP on 5xFAD, a transgenic mouse model of AD. Toward this aim, we used 20 5xFAD mice in two groups (n = 10 each), VIP-treated (25 ng/kg i.p. injection, three times per week) and saline-treated (the drug's vehicle) following the same administration regimen. Treatment started at 1 month of age and ended 2 months later. After 2 months of treatment, the mice were euthanized, their brains dissected out, and immunohistochemically stained for Aβ₄₀ and Aβ₄₂ on serial sections. Then, plaque analysis and stereological morphometric analysis were performed in different brain regions. Chronic VIP administration in 5xFAD mice significantly decreased the levels of Aβ₄₀ and Aβ₄₂ plaques in the subiculum compared to the saline treated 5xFAD mice. VIP treatment also significantly decreased Aβ₄₀ and Aβ₄₂ plaques in cortical areas and significantly increased the hippocampus/cerebrum and corpus callosum/cerebrum ratio but not the cerebral cortex/cerebrum ratio. In summary, we found that chronic administration of VIP significantly decreased Aβ plaques and preserved against atrophy for related brain regions in 5xFAD AD mice.

Three-Dimensional in Vitro Cell Culture Models in Drug Discovery and Drug Repositioning

Drug development is a lengthy and costly process that proceeds through several stages from target identification to lead discovery and optimization, preclinical validation and clinical trials culminating in approval for clinical use. An important step in this process is high-throughput screening (HTS) of small compound libraries for lead identification. Currently, the majority of cell-based HTS is being carried out on cultured cells propagated in two-dimensions (2D) on plastic surfaces optimized for tissue culture. At the same time, compelling evidence suggests that cells cultured in these non-physiological conditions are not representative of cells residing in the complex microenvironment of a tissue. This discrepancy is thought to be a significant contributor to the high failure rate in drug discovery, where only a low percentage of drugs investigated ever make it through the gamut of testing and approval to the market. Thus, three-dimensional (3D) cell culture technologies that more closely resemble in vivo cell environments are now being pursued with intensity as they are expected to accommodate better precision in drug discovery. Here we will review common approaches to 3D culture, discuss the significance of 3D cultures in drug resistance and drug repositioning and address some of the challenges of applying 3D cell cultures to high-throughput drug discovery.

Secretome released from hydrogel-embedded adipose mesenchymal stem cells protects against the Parkinson's disease related toxin 6-hydroxydopamine

Neurodegenerative diseases, as Parkinson’s disease (PD), involve irreversible neural cell damage and impairment. In PD, there is a selective degeneration of the dopaminergic neurons leading to motor symptoms. A common finding in PD neurodegeneration is the increase of reactive oxygen species (ROS), leading to oxidative stress. To date there are only interventions to relieve PD symptoms, however progress has been made in the development of therapies that target the immune system or use its components as therapeutic agents; among these, mesenchymal stem cells (MSCs), which are able to express neuroprotective factors as cytokines, chemokines and angiogenic molecules, collectively named secretome, that accumulate in MSC culture medium. However, lasting cell-free administration of secretome in vitro or in vivo is challenging. We used the conditioned media from rat adipose tissue-derived MSCs (RAA-MSCs) to check for neuroprotective activity towards pro-oxidizing agents such as hydrogen peroxide (H₂O₂) or the dopaminergic selective toxin 6-hydroxydopamine (6-OHDA) that is commonly used to model PD neurodegeneration. When neuroblastoma SH-SY5Y cells were pre-conditioned with 100% RAA-MSC media, then treated with H₂O₂ and 6-OHDA, mortality and ROS generation were reduced. We implemented the controlled release of RAA-MSC secretome from injectable biodegradable hydrogels that offer a possible in situ implant with mini-invasive techniques. The hydrogels were composed of type I bovine collagen (COLL) and low-molecular-weight hyaluronic acid (LMWHA) or COLL and polyethylene glycol (PEG). Hydrogels were suitable for RAA-MSC embedding up to 48 h and secretome from these RAA-MSCs was active and counteracted 6-OHDA toxicity, with upregulation of the antioxidant enzyme sirtuin 3 (SIRT3). These results support a biomaterials-based approach for controlled delivery of MSC-produced neuroprotective factors in a PD-relevant experimental context.

Nanomaterials for In Vivo Imaging

In vivo imaging, which enables us to peer deeply within living subjects, is producing tremendous opportunities both for clinical diagnostics and as a research tool. Contrast material is often required to clearly visualize the functional architecture of physiological structures. Recent advances in nanomaterials are becoming pivotal to generate the high-resolution, high-contrast images needed for accurate, precision diagnostics. Nanomaterials are playing major roles in imaging by delivering large imaging payloads, yielding improved sensitivity, multiplexing capacity, and modularity of design. Indeed, for several imaging modalities, nanomaterials are now not simply ancillary contrast entities, but are instead the original and sole source of image signal that make possible the modality's existence. We address the physicochemical makeup/design of nanomaterials through the lens of the physical properties that produce contrast signal for the cognate imaging modality-we stratify nanomaterials on the basis of their (i) magnetic, (ii) optical, (iii) acoustic, and/or (iv) nuclear properties. We evaluate them for their ability to provide relevant information under preclinical and clinical circumstances, their in vivo safety profiles (which are being incorporated into their chemical design), their modularity in being fused to create multimodal nanomaterials (spanning multiple different physical imaging modalities and therapeutic/theranostic capabilities), their key properties, and critically their likelihood to be clinically translated.

Caspase-1 causes truncation and aggregation of the Parkinson's disease-associated protein α-synuclein

The aggregation of α-synuclein (aSyn) leading to the formation of Lewy bodies is the defining pathological hallmark of Parkinson's disease (PD). Rare familial PD-associated mutations in aSyn render it aggregation-prone; however, PD patients carrying wild type (WT) aSyn also have aggregated aSyn in Lewy bodies. The mechanisms by which WT aSyn aggregates are unclear. Here, we report that inflammation can play a role in causing the aggregation of WT aSyn. We show that activation of the inflammasome with known stimuli results in the aggregation of aSyn in a neuronal cell model of PD. The insoluble aggregates are enriched with truncated aSyn as found in Lewy bodies of the PD brain. Inhibition of the inflammasome enzyme caspase-1 by chemical inhibition or genetic knockdown with shRNA abated aSyn truncation. In vitro characterization confirmed that caspase-1 directly cleaves aSyn, generating a highly aggregation-prone species. The truncation-induced aggregation of aSyn is toxic to neuronal culture, and inhibition of caspase-1 by shRNA or a specific chemical inhibitor improved the survival of a neuronal PD cell model. This study provides a molecular link for the role of inflammation in aSyn aggregation, and perhaps in the pathogenesis of sporadic PD as well.

Fluorescence imaging of in vivo miR-124a-induced neurogenesis of neuronal progenitor cells using neuron-specific reporters

Background

Facilitation of the differentiation of the stem cells toward neuronal lineage is crucial for enhancing the differentiation efficacy of grafted stem cells for the possible treatment of neurodegenerative disorders. MicroRNA124a (miR-124a) has been considered as a neuronal lineage regulator, possessing the capability to activate neuronal differentiation. In this study, using a neuronal promoter-based reporter and live-cell fluorescence imaging, we visualized in vitro and in vivo the enhanced neuronal differentiation of neuronal progenitor cells with miR-124a overproduction.

Methods

The neuron specific alpha1 tubulin promoter-driven RFP reporter (pTa1-RFP) was used to trace the miR-124a-induced neuronal differentiation in live cell condition. MiR-124a or miR-scramble in 10 % glucose buffer was mixed with in vivo-jetPEITM and in vivo fluorescence images were obtained daily using Maestro spectral fluorescent imager.

Results

Neurite outgrowth was clearly seen in F11 cells after miR-124a transfection, and immunofluorescence staining showed increase of Tuj1 and NF at 48 hours. When pTa1-RFP-transfected F11 cells were implanted simultaneously with miR-124a into the nude mice, gradually increasing reporter signals and morphological changes indicated neuronal differentiation for 48 hours in live cells in vitro. The miR-124a-treated F11 cells showed higher reporter signals on in vivo fluorescence imaging than miR-scramble-treated cells, which were verified by ex vivo confirmation of Tuj1 and NF expression.

Conclusions

These results indicated that neuronal reporter-based neurogenesis imaging can be used for monitoring miR-124a acting as neuronal activator when miRNA was injected in in vivo PEI-coated form for miRNA-mediated regenerative therapy.

Statistical research on the bioactivity of new marine natural products discovered during the 28 years from 1985 to 2012

Every year, hundreds of new compounds are discovered from the metabolites of marine organisms. Finding new and useful compounds is one of the crucial drivers for this field of research. Here we describe the statistics of bioactive compounds discovered from marine organisms from 1985 to 2012. This work is based on our database, which contains information on more than 15,000 chemical substances including 4196 bioactive marine natural products. We performed a comprehensive statistical analysis to understand the characteristics of the novel bioactive compounds and detail temporal trends, chemical structures, species distribution, and research progress. We hope this meta-analysis will provide useful information for research into the bioactivity of marine natural products and drug development.

'As above, so below' examining the interplay between emotion and the immune system

While the concept of a palpable relationship between our mental and physical well-being is certainly not new, it is only in the light of modern scientific research that we have begun to realize how deeply connected our emotional and immune states may be. We begin this review with a series of studies demonstrating how four fundamental emotional responses: anger, anxiety, mirth and relaxation are able modulate cytokine production and cellular responses to a variety of immune stimuli. These modulations are shown to be either detrimental or beneficial to a patient's health dependent on the context and duration of the emotion. We also discuss the reverse, highlighting research demonstrating how the loss of key immune cells such as T lymphocytes in clinical and animal studies can negatively impact both emotional well-being and cognition. Additionally, to give a more complete picture of the manifold pathways that link emotion and the immune system, we give a brief overview of the influence the digestive system has upon mental and immunological health. Finally, throughout this review we attempt to highlight the therapeutic potential of this burgeoning field of research in both the diagnosis and treatment of immune and disorders. As well as identifying some of the key obstacles the field must address in order to put this potential into practice.

New immunological approaches in treating and diagnosing CNS diseases

The immune system evolved to launch effective and specific responses against pathogens. A key feature of this defense mechanism is its ability to differentiate between self and nonself. However, in autoimmune diseases, the host's immune system fails to discriminate self versus foreign. The CNS is further protected by the blood-brain barrier. In spite of its 'immune privilege,' the brain is not protected from autoimmunity; perhaps paradoxically xenoantibodies can be used to treat neurological diseases. We describe patents covering treatment methods for CNS diseases with suspected or demonstrated autoimmune etiology. These include multiple sclerosis and, Alzheimer's and Parkinson's disease. The goal is to less invasively, yet efficiently, treat neurological diseases. Although autoimmune responses are often detrimental, recent studies have begun to harness, boost and induce immune responses as a mechanism of treatment. The patents discussed herein highlight new treatments for Alzheimer's and Parkinson's disease, multiple sclerosis, and seizure disorders.

Expression of the protein chaperone, clusterin, in spinal cord cells constitutively and following cellular stress, and upregulation by treatment with Hsp90 inhibitor

Clusterin, a protein chaperone found at high levels in physiological fluids, is expressed in nervous tissue and upregulated in several neurological diseases. To assess relevance to amyotrophic lateral sclerosis (ALS) and other motor neuron disorders, clusterin expression was evaluated using long-term dissociated cultures of murine spinal cord and SOD1(G93A) transgenic mice, a model of familial ALS. Motor neurons and astrocytes constitutively expressed nuclear and cytoplasmic forms of clusterin, and secreted clusterin accumulated in culture media. Although clusterin can be stress inducible, heat shock failed to increase levels in these neural cell compartments despite robust upregulation of stress-inducible Hsp70 (HspA1) in non-neuronal cells. In common with HSPs, clusterin was upregulated by treatment with the Hsp90 inhibitor, geldanamycin, and thus could contribute to the neuroprotection previously identified for such compounds in disease models. Clusterin expression was not altered in cultured motor neurons expressing SOD1(G93A) by gene transfer or in presymptomatic SOD1(G93A) transgenic mice; however, clusterin immunolabeling was weakly increased in lumbar spinal cord of overtly symptomatic mice. More striking, mutant SOD1 inclusions, a pathological hallmark, were strongly labeled by anti-clusterin. Since secreted, as well as intracellular, mutant SOD1 contributes to toxicity, the extracellular chaperoning property of clusterin could be important for folding and clearance of SOD1 and other misfolded proteins in the extracellular space. Evaluation of chaperone-based therapies should include evaluation of clusterin as well as HSPs, using experimental models that replicate the control mechanisms operant in the cells and tissue of interest.

Therapeutic antibodies in stroke

Immunotherapy represents an active area of biomedical research to treat cancer, autoimmune diseases, and neurodegenerative disorders. In stroke, recanalization therapy is effective in reducing brain tissue damage after acute ischemic stroke. However, the narrow time window restricts its application for the majority of stroke patients. There is an urgent need to develop adjuvant therapies such as immunotherapy, stem cell replacement, and neuroprotective drugs. A number of molecules have been targeted for immunotherapy in stroke management, including myelin-associated proteins and their receptors, N-methyl-d-aspartic acid receptors, cytokines, and cell adhesion molecules. Both active vaccination and passive antibodies were tested in animal models of acute ischemic stroke. However, the mechanisms underlying the efficacy of immunotherapy are different for each target protein. Blocking myelin-associated proteins may enhance neuroplasticity, whereas blocking adhesion molecules may yield neuroprotection by suppressing the immune response after stroke. Although results from animal studies are encouraging, clinical trials using therapeutic antibodies failed to improve stroke outcome due to severe side effects. It remains a challenge to generate specific therapeutic antibodies with minimal side effects on other organs and systems.

CD4⁺ but not CD8⁺ T cells revert the impaired emotional behavior of immunocompromised RAG-1-deficient mice

An imbalanced immune system has long been known to influence a variety of mood disorders including anxiety, obsessive-compulsive disorders and depression. In this study, we sought to model the impact of an immunocompromised state on these emotional behaviors using RAG-1⁻/⁻ mice, which lack T and B cells. We also investigated the relative contribution of CD4⁺ or CD8⁺ T cells to these manifestations using RAG-1⁻/⁻/OT-II and RAG-1⁻/⁻/OT-I transgenic mice, respectively. Our results show that RAG-1⁻/⁻ mice present a significant increase in digging and marble-burying activities compared with wild-type mice. Surprisingly, these anxiety-like behaviors were significantly reverted in RAG-1⁻/⁻/OT-II but not RAG-1⁻/⁻/OT-I transgenic mice. Immunodepletion experiments with anti-CD4 or anti-CD8 in C57/BL6 mice or repopulation studies in RAG-1⁻/⁻ mice did not reproduce these findings. Microarray analysis of the brain of RAG-1⁻/⁻ and RAG-1⁻/⁻/OT-II mice revealed a significantly different gene fingerprint, with the latter being more similar to wild-type mice than the former. Further analysis revealed nine main signaling pathways as being significantly modulated in RAG-1⁻/⁻ compared with wild-type mice. Taken together, these results suggest that life-long rather than transient immunodeficient conditions influence the emotional behaviors in mice. Most interestingly, these effects seem to correlate with a specific absence of CD4⁺ rather than CD8⁺ T cells. Validation of these findings in man might provide new clues on the mechanism by which early life immune modulation might impact mood response in adults and provide a further link between immune and emotional well-being.

Pathways towards an effective immunotherapy for Parkinson's disease

Immunizations that target specific types of immune responses are used commonly to prevent microbial infections. However, a range of immune responses may prove necessary to combat the ravages of neurodegenerative diseases. The goal is to eliminate the 'root' cause of neurodegenerative disorders, misfolded aggregated proteins, while harnessing adaptive immune responses to promote neural repair. However, immunization strategies used to elicit humoral immune responses against aberrant brain proteins have yielded mixed success. While specific proteins can be cleared, the failures in halting disease progression revolve, in measure, around adaptive immune responses that promote autoreactive T cells and, as such, induce a meningoencephalitis, accelerating neurodegeneration. Thus, alternative approaches for protein clearance and neural repair are desired. To this end, our laboratories have sought to transform autoreactive adaptive immune responses into regulatory neuroprotective cells in Parkinson's disease. In this context, induction of immune responses against modified brain proteins serves to break immunological tolerance, while eliciting adaptive immunity to facilitate neuronal repair. How to harness the immune response in the setting of Parkinson's disease requires a thorough understanding of the role of immunity in human disease and the ways to modify such immune responses to elicit therapeutic gain. These are discussed in this review.

Different molecular pathologies result in similar spatial patterns of cellular inclusions in neurodegenerative disease: a comparative study of eight disorders

Recent research suggests cell-to-cell transfer of pathogenic proteins such as tau and α-synuclein may play a role in neurodegeneration. Pathogenic spread along neural pathways may give rise to specific spatial patterns of the neuronal cytoplasmic inclusions (NCI) characteristic of these disorders. Hence, the spatial patterns of NCI were compared in four tauopathies, viz., Alzheimer's disease, Pick's disease, corticobasal degeneration, and progressive supranuclear palsy, two synucleinopathies, viz., dementia with Lewy bodies and multiple system atrophy, the 'fused in sarcoma' (FUS)-immunoreactive inclusions in neuronal intermediate filament inclusion disease, and the transactive response DNA-binding protein (TDP-43)-immunoreactive inclusions in frontotemporal lobar degeneration, a TDP-43 proteinopathy (FTLD-TDP). Regardless of molecular group or morphology, NCI were most frequently aggregated into clusters, the clusters being regularly distributed parallel to the pia mater. In a significant proportion of regions, the regularly distributed clusters were in the size range 400-800 μm, approximating to the dimension of cell columns associated with the cortico-cortical pathways. The data suggest that cortical NCI in different disorders exhibit a similar spatial pattern in the cortex consistent with pathogenic spread along anatomical pathways. Hence, treatments designed to protect the cortex from neurodegeneration may be applicable across several different disorders.

Peripheral immune contributions to the maintenance of central glial activation underlying neuropathic pain

Recent evidence implicates an adaptive immune response in the central nervous system (CNS) mechanisms of neuropathic pain. This review identifies how neuropathic pain alters CNS immune privilege to facilitate T cell infiltration. Once in the CNS, T cells may interact with the local antigen presenting cells, microglia, via the major histocompatibility complex and the costimulatory molecules CD40 and B7. In this way, T cells may contribute to the maintenance of neuropathic pain through pro-inflammatory interactions with microglia and by facilitating the activation of astrocytes in the spinal dorsal horn. Based on the evidence presented in this review, we suggest that this bidirectional, pro-inflammatory system of neurons, glia and T cells in neuropathic pain should be renamed the pentapartite synapse, and identifies the latest member as a potential disease-modifying therapeutic target.

Combined anti-inflammatory effects of β2-adrenergic agonists and PDE4 inhibitors on astrocytes by upregulation of intracellular cAMP

Inflammation is an important hallmark of all neurodegenerative diseases and activation of different glial populations may be involved in the progression of some of these disorders. Especially, the activation of astroglia can lead to long-term detrimental morphological changes, such as scar formation. Therefore, improved strategies to modulate inflammation in these cells are currently being investigated. We investigated the interaction of phosphodiesterase (PDE) 4 inhibitors, such as rolipram, with other agents raising cellular cAMP levels. When used alone, none of the PDE4 inhibitors increased cAMP levels. The adenylate cyclase activator forskolin, the β(2)-adrenergic agonist clenbuterol and the mixed β(1)/β(2)-adrenergic agonist isoproterenol increased intracellular cAMP levels of cortical murine astrocytes. This increase was synergistically elevated by rolipram or the PDE4 inhibitor RO-201724, but not by inhibition of PDE3. Inflammatory stimulation of the cells with the cytokines TNF-α, IL-1β and IFN-γ strongly induced PDE4B and augmented overall PDE4 activity, while PDE3 activity was low. Clenbuterol and forskolin caused downregulation of cytokines and chemokines such as IL-6 and MCP-1. This effect was further enhanced by rolipram, but not by the PDE3 inhibitor milrinone. The cAMP-raising drug combinations attenuated the upregulation of TNF-α and IL-6 mRNA and the secretion of IL-6, but did not affect initial NF-κB signalling triggered by the stimulating cytokines. These results indicate that PDE4 may be a valuable anti-inflammatory target in brain diseases, especially under conditions associated with stimulation of cAMP-augmenting astrocyte receptors as is observed by clenbuterol treatment.

Immunolocalization of influenza A virus and markers of inflammation in the human Parkinson's disease brain

Although much is known regarding the molecular mechanisms leading to neuronal cell loss in Parkinson's disease (PD), the initiating event has not been identified. Prevailing theories including a chemical insult or infectious agent have been postulated as possible triggers, leading to neuroinflammation. We present immunohistochemical data indicating the presence of influenza A virus within the substantia nigra pars compacta (SNpc) from postmortem PD brain sections. Influenza A virus labeling was identified within neuromelanin granules as well as on tissue macrophages in the SNpc. Further supporting a role for neuroinflammation in PD was the identification of T-lymphocytes that colocalized with an antibody to caspase-cleaved Beclin-1 within the SNpc. The presence of influenza A virus together with macrophages and T-lymphocytes may contribute to the neuroinflammation associated with this disease.

A deadly spread: cellular mechanisms of α-synuclein transfer

Classically, Parkinson's disease (PD) is linked to dopamine neuron death in the substantia nigra pars compacta. Intracytoplasmic protein inclusions named Lewy bodies, and corresponding Lewy neurites found in neuronal processes, are also key features of the degenerative process in the substantia nigra. The molecular mechanisms by which substantia nigra dopamine neurons die and whether the Lewy pathology is directly involved in the cell death pathway are open questions. More recently, it has become apparent that Lewy pathology gradually involves greater parts of the PD brain and is widespread in late stages. In this review, we first discuss the role of misfolded α-synuclein protein, which is the main constituent of Lewy bodies, in the pathogenesis of PD. We then describe recent evidence that α-synuclein might transfer between cells in PD brains. We discuss in detail the possible molecular mechanisms underlying the proposed propagation and the likely consequences for cells that take up α-synuclein. Finally, we focus on aspects of the pathogenic process that could be targeted with new pharmaceutical therapies or used to develop biomarkers for early PD detection.

Inflammation and gliosis in neurological diseases--clinical implications

The inflammatory reaction accompany all acute processes in the central nervous system (CNS), (as stroke or traumatic brain injury) and chronic neurodegenerative processes (as Parkinson's or Alzheimer's disease), and through the stage of cleaning of damage tissue, contribute to recovery and regeneration and eventually to restoration of the function. However many studies showed that inflammation in the CNS may be harmful because of an excessive vulnerability of the nervous tissue or impaired regulation. Manipulation of the inflammation is now one of the approaches in the treatment of the various diseases of the CNS.

Marine natural product drug discovery: Leads for treatment of inflammation, cancer, infections, and neurological disorders

Natural products, secondary metabolites, isolated from plants, animals and microbes are important sources for bioactive molecules that in many cases have been developed into treatments for diseases. This review will focus on describing the potential for finding new treatments from marine natural products for inflammation, cancer, infections, and neurological disorders. Historically terrestrial natural products have been studied to a greater extent and such classic drugs as aspirin, vincristine and many of the antibiotics are derived from terrestrial natural products. The need for new therapeutics in the four areas mentioned is dire. Within the last 30 years marine natural products, with their unique structures and high level of halogenation, have shown many promising activities against the inflammatory response, cancer, infections and neurological disorders. The review will outline examples of such compounds and activities.

Preclinical studies of methylthioadenosine for the treatment of multiple sclerosis

BACKGROUND

Methylthioadenosine (MTA) is a natural metabolite with immunomodulatory properties. MTA improves the clinical course and pathology of the animal model of multiple sclerosis, even when therapy is started after disease onset.

OBJECTIVE

Our aim was to compare the efficacy of MTA in ameliorating experimental autoimmune encephalomyelitis (EAE) compared with first line approved therapies, to develop an oral formulation of MTA and to assess its pharmacokinetic profile.

METHODS

EAE was induced in C57BL/6 mice by immunization with MOG(35-55) peptide in Freund's Adjuvant. Animals were treated with MTA, interferon-beta or glatiramer acetate starting the day of immunization and the clinical score was collected blind. Pharmacokinetic studies were performed in Sprague Dawley rats by administering MTA by intraperitoneal injection and orally, and collecting blood at different intervals. MTA levels were measured by high-performance liquid chromatography.

RESULTS

We found that MTA ameliorated EAE in a dose-response manner. Moreover, the highest dose of MTA (60 mg/kg) was more efficacious than mouse interferon-beta or glatiramer acetate. We developed a salt of MTA for oral administration, with similar dose-response effect in the EAE model. Combination therapy assays between MTA and interferon-beta or glatiramer acetate were more effective than the individual therapies. Finally, oral MTA half-life was 20 min, with a C(max) of 80 mg/L and without signs of obvious toxicity (animal death, behavioural changes, liver enzymes).

CONCLUSIONS

In the EAE model MTA is more efficacious than first line therapies for multiple sclerosis, with a dose- response effect and higher efficacy when combined with interferon-beta or glatiramer acetate. Oral MTA was also effective in the animal model of multiple sclerosis.

Selective MyD88-dependent pathway inhibition by the cyanobacterial natural product malyngamide F acetate

In response to evolutionary selective pressure, prokaryotes have developed a rich array of secondary metabolites, some of which may be inhibitory to the innate immune system and the inflammatory response in vertebrates. We utilized the RAW264.7 macrophage cell line stimulated with LPS in a nitric oxide (NO) assay to screen for compounds with immunomodulatory activities from a library of marine natural products, and found that the malyngamide structure class, found commonly in the marine cyanobacterium Lyngbya majuscula, has potent activity. Several of the malyngamides were found to possess IC50 values of 5.4-18microM. Malyngamide F acetate exhibited strong concentration-dependent anti-inflammatory activity in the NO assay with an IC50 of 7.1microM and with no cytotoxicity at the concentrations tested. Subsequent real-time PCR of selected genes revealed a unique cytokine profile after LPS stimulation (TLR4) with decreased expression of iNOS, IL-1beta, IL-6, and IL-10, but increased TNF-alpha expression. Additional experiments utilizing CpG and Poly I:C stimulation to selectively activate the MyD88-dependent and -independent pathways via TLR9 and TLR3 substantiated the finding that malyngamide F acetate selectively inhibits the MyD88-dependent pathway. To our knowledge, this is the first report of a natural product inhibiting the MyD88-dependent pathway.

Lack of functional relevance of isolated cell damage in transplants of Parkinson's disease patients

Postmortem analyses from clinical neural transplantation trials of several subjects with Parkinson's disease revealed surviving grafted dopaminergic neurons after more than a decade. A subset of these subjects displayed isolated dopaminergic neurons within the grafts that contained Lewy body-like structures. In this review, we discuss why this isolated cell damage is unlikely to affect the overall graft function and how we can use these observations to help us to understand age-related neurodegeneration and refine our future cell replacement therapies.

Advances in imaging of new targets for pharmacological intervention in stroke: real-time tracking of T-cells in the ischaemic brain

BACKGROUND AND PURPOSE

T-cells may play a role in the evolution of ischaemic damage and repair, but the ability to image these cells in the living brain after a stroke has been limited. We aim to extend the technique of real-time in situ brain imaging of T-cells, previously shown in models of immunological diseases, to models of experimental stroke.

EXPERIMENTAL APPROACH

Male C57BL6 mice (6-8 weeks) (n= 3) received a total of 2-5 x 10(6) carboxyfluorescein diacetate succinimidyl ester (CFSE)-labelled lymphocytes from donor C57BL6 mice via i.v. injection by adoptive transfer. Twenty-four hours later, recipient mice underwent permanent left distal middle cerebral artery occlusion (MCAO) by electrocoagulation or by sham surgery under isoflurane anaesthesia. Female hCD2-green fluorescent protein (GFP) transgenic mice that exhibit GFP-labelled T-cells underwent MCAO. At 24 or 48 h post-MCAO, a sagittal brain slice (1500 microm thick) containing cortical branches of the occluded middle cerebral artery (MCA) was dissected and used for multiphoton laser scanning microscopy (MPLSM).

KEY RESULTS

Our results provide direct observations for the first time of dynamic T-cell behaviour in living brain tissue in real time and herein proved the feasibility of MPLSM for ex vivo live imaging of immune response after experimental stroke.

CONCLUSIONS AND IMPLICATIONS

It is hoped that these advances in the imaging of immune cells will provide information that can be harnessed to a therapeutic advantage.

Heterogeneity of microglial activation in the innate immune response in the brain

The immune response in the brain has been widely investigated and while many studies have focused on the proinflammatory cytotoxic response, the brain's innate immune system demonstrates significant heterogeneity. Microglia, like other tissue macrophages, participate in repair and resolution processes after infection or injury to restore normal tissue homeostasis. This review examines the mechanisms that lead to reduction of self-toxicity and to repair and restructuring of the damaged extracellular matrix in the brain. Part of the resolution process involves switching macrophage functional activation to include reduction of proinflammatory mediators, increased production and release of anti-inflammatory cytokines, and production of cytoactive factors involved in repair and reconstruction of the damaged brain. Two partially overlapping and complimentary functional macrophage states have been identified and are called alternative activation and acquired deactivation. The immunosuppressive and repair processes of each of these states and how alternative activation and acquired deactivation participate in chronic neuroinflammation in the brain are discussed.

Viral-like brain inflammation during development causes increased seizure susceptibility in adult rats

Viral infections of the CNS and their accompanying inflammation can cause long-term neurological effects, including increased risk for seizures. To examine the effects of CNS inflammation, we infused polyinosinic:polycytidylic acid, intracerebroventricularly to mimic a viral CNS infection in 14 day-old rats. This caused fever and an increase in the pro-inflammatory cytokine, interleukin (IL)-1beta in the brain. As young adults, these animals were more susceptible to lithium-pilocarpine and pentylenetetrazol-induced seizures and showed memory deficits in fear conditioning. Whereas there was no alteration in adult hippocampal cytokine levels, we found a marked increase in NMDA (NR2A and C) and AMPA (GluR1) glutamate receptor subunit mRNA expression. The increase in seizure susceptibility, glutamate receptor subunits, and hippocampal IL-1beta levels were suppressed by neonatal systemic minocycline. Thus, a novel model of viral CNS inflammation reveals pathophysiological relationships between brain cytokines, glutamate receptors, behaviour and seizures, which can be attenuated by anti-inflammatory agents like minocycline.

Neuroprotection of microglial conditioned medium on 6-hydroxydopamine-induced neuronal death: role of transforming growth factor beta-2

Microglia, the immune cells of the CNS, play essential roles in both physiological and pathological brain states. Here we have used an in vitro model to demonstrate neuroprotection of a 48 h-microglial conditioned medium (MCM) towards cerebellar granule neurons (CGNs) challenged with the neurotoxin 6-hydroxydopamine, which induces a Parkinson-like neurodegeneration, and to identify the protective factor(s). MCM nearly completely protects CGNs from 6-hydroxydopamine neurotoxicity and at least some of the protective factor(s) are peptidic in nature. While the fraction of the medium containing molecules < 30 kDa completely protects CGNs, fractions containing molecules < 10 kDa or > 10 kDa are not neuroprotective. We further demonstrate that microglia release high amounts of transforming growth factor-beta2 (TGF-beta2) and that its exogenous addition to the fraction of the medium not containing it (< 10 kDa) fully restores the neuroprotective action. Moreover, MCM neuroprotection is significantly counteracted by an inhibitor of TGF-beta2 transduction pathway. Our results identify TGF-beta2 as an essential neuroprotective factor released by microglia in its culture medium that requires to be fully effective the concomitant presence of other factor(s) of low molecular weight.

Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest regarding a broad scope of topics are abstracted monthly.