Medicinal Chemistry - Volume 14, Issue 2, 2018

Background: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Of the plethora of motor and sensory disturbances experienced by sufferers, neuropathic pain is a highly prevalent and debilitating symptom, and at present remains extremely difficult to treat. Common forms of neuropathic pain seen in MS patients include central neuropathic pain, Lhermitte's phenomenon and trigeminal neuralgia, which are all speculated to arise from specific patterns of lesion formation. Objective: Efficacious pharmacological interventions for the treatment of neuropathic pain associated with MS are lacking, and have been largely informed by drug trials in peripheral neuropathies and spinal cord injury. Method/Results: Neuropathic pain in MS is inadequately relieved by conventional analgesics, and first-line therapies are generally comprised of anti-depressive and anti-convulsive drugs. A range of alternatives have been proposed and tested with variable success, including cannabinoids and certain opioid analgesics. Animals with experimental autoimmune encephalomyelitis (EAE), an autoimmune model of MS, also exhibit neuropathic pain symptoms. Conclusion: Studies aimed at understanding the mechanisms underlying EAE-induced neuropathic pain and investigating the efficacy of novel pharmacological interventions at the animal level offer an exciting area of future research, and may inform future therapeutic options for MS-associated neuropathic pain.

Background: Myelin oligodendrocyte glycoprotein (MOG) is located on the external surface of myelin, a membranous component of the central nervous system (CNS) that forms the insulating lipid layer around neurons. The major MOG splicing variant (a1 transcript) encodes a transmembrane protein with an extracellular domain of an Ig variable (IgV) fold. MOG IgV domains from the same or different cells dimerize and contribute to the organization and maintenance of the myelin sheath in neurons. The encepalitogenic T cells recognize MOG and its immunodominant epitopes (epitopes 1-22, 35-55 and 92-106 located at the dimer interface) as foreign antigens and cause the destruction of myelin (demyelination) leading to the clinical condition known as multiple sclerosis (MS). Recognition of the antigen takes place in the context of the trimolecular complex formed by HLA, MOGpeptides and TCR. Objective: Understanding the role of MOG in MS. Method/Results: We have reviewed herein, the genomic organization of the human MOG gene, the structural characteristics of the MOG protein, the involvement of MOG in MS and clinical studies for the treatment of MS based on MOG peptide analogues. Conclusion: Conjugates of antigenic MOG peptides to mannan and combinations of antigenic MOG and other peptides chemically linked to cells of the immune system may modify the immune response, alleviating in some cases the symptoms of MS.

Background: Multiple sclerosis (MS) is a progressive, demyelinating condition of the central nervous system, manifesting in loss or alterations in function of sensory, motor and cognitive function. Of the various environmental and behavioural risk factors identified as playing a role in MS onset and progression, perhaps none has been as consistent as vitamin D. Objective: In this review, we will endeavour to present a general background on the role of vitamin D in human health and particularly in MS, as well as the substantial epidemiological evidence in support of vitamin D's role in MS. Results: Initially identified via the oft-noted latitudinal gradient in MS prevalence and incidence, vitamin D has since been demonstrated to have a strong and consistent inverse association with MS risk and clinical course. Cases have much lower levels of the diagnostic metabolite of vitamin D, 25- hydroxyvitamin D (25(OH)D) compared to healthy controls, while those with more active disease have lower levels of 25(OH)D than other cases with less active disease. These case-control and crosssectional study results led the way to cohort studies which indicated significant inverse associations between serum 25(OH)D and clinical activity in MS. The combined weight of indirect and direct observational evidence have been the impetus for completed and ongoing randomised trials of vitamin D supplementation, alone or in addition to standard immunomodulatory medications, as an intervention in MS onset and clinical course. Moreover, in addition to being a distinct factor in MS aetiology, vitamin D has been demonstrated to interact with a variety of other risk factors, from genetic predictors like HLA-DR1 genotype to behavioural factors like smoking. Conclusion: There is an abundance of epidemiological evidence, both direct and indirect, as well as significant biological plausibility substantiating a role for vitamin D in the onset & progression of multiple sclerosis.

Background: Monoclonal antibodies (mAbs) are now established as targeted therapies for malignancies, transplant rejection, autoimmune and infectious diseases. Two monoclonal antibodies are available for treatment and other antibodies are currently being tested in multiple sclerosis (MS) patients. Objectives: The purpose of the present review paper is to outline the antibody engineering technologies, the immunologic and pharmacologic concepts of mAbs and the current status of treatment in MS with emphasis on clinical efficacy and safety. Method: We conducted a through review of the scientific literature published until 31 December 2014 (print and electronic publications) concerning the production, applications and side effects of the use of Mabs. Sixty five articles were used in total (both original research and review papers). Conclusion: With the introduction of mAbs the treatment of MS has entered a new era, both with respect to efficacy and target specificity. However, administration of mAbs carries the risk of immune reactions such as acute anaphylaxis, serum sickness, infection and other autoimmune diseases. In addition, unexpected consequences arise from our incomplete knowledge of the immune system. For example, natalizumab, a monoclonal antibody targeting α4-integrin on leukocytes increases the risk of developing progressive multifocal leukoencephalopathy, without causing notable immunosuppression. Further study on the use of mabs is required, both in vitro and in the clinical field, in order to increase our knowledge upon these new revolutionary therapeutic agents.

Background: Matrix metalloproteinases (MMPs) are zinc-containing endopeptidases, proteins essential to the degradation of various tissue extracellular matrix proteins. Under normal conditions, MMPs participate in several physiological processes, both in the developing organism and the adult. Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS), affecting primarily young adults. Inflammatory infiltrations of the CNS parenchyma by autoreactive immune cells, that mediate myelin degradation in the form of the demyelination “plaque”, are the pathological hallmark of the disease. Due to their capacity to orchestrate tissue penetration from various cells, MMPs have been elucidated in MS as mediators of blood-brain barrier disruption and CNS inflammation, thus contributing to the disease pathogenesis. Objective: This review focuses on clinical and experimental evidence of MMPs' pathogenetic role in MS and its animal model, experimental autoimmune encephalomyelitis (EAE). Method: A MEDLINE search was performed for using the following terms: “metalloproteinases”, “multiple sclerosis”, “experimental autoimmune encephalomyelitis”, “central nervous system” and “autoimmunity”. Results: Expression patterns of MMPs and their specific inhibitor molecules at the sites of MS and EAE lesions, as well as by specific cell types of the immune system, provide evidence of MMPs' role in the pathogenesis of CNS autoimmunity. Clinical evidence suggests differential profile of MMPs' expression in serum and cerebrospinal fluid (CSF) between MS patients with various disease types and healthy adults, rendering MMPs potential biomarkers for disease incidence and activity. Conclusion: MMPs' role in the processes of CNS inflammation, de- and remyelination, confers implications as therapeutic targets, either alone, or in relation with widely-used disease modifying treatments in MS.

Background: Damage to the myelin sheath (demyelination) is one of the main manifestations of multiple sclerosis (MS). Interestingly, both MS and vitamin B deficiencies result in severe myelin degeneration, leading to loss in neuronal signal transmission. Objective: Deficiency in vitamin B complex vary, although common symptoms include fatigue, increased oxidative stress, inflammation and demyelination. In particular, vitamin B12 (cobalamin) has had increased attention for its role in the methylation process, involvement in myelination and remyelination, and reversal of MS symptoms. Method: Here, we discuss the role of vitamin B complex (B1, B2, B3, B4, B5, B6, B7, B9, B12) in MS. Results: The anti-inflammatory and re-myelinating attributes of vitamin B complex members are promising, despite limited clinical studies. Conclusion: There is an urgent need for larger studies to determine the role of vitamin B supplementation alone, or in combination with other therapeutic agents, in prevention or reversal of MS, and aid in improved quality of life of MS patients.

Background: Cancers of the lymphatic cells (lymphomas) account for approximately 12% of malignant diseases worldwide. The nitrostyrene scaffold is identified as a lead target structure for the development of particularly effective compounds targeting Burkitt's lymphoma (BL). Objectives: The aims of the curent study were to synthesise a panel of nitrostyrene compounds and to evaluate their activity in Burkitt's lymphoma (BL). Methods: A panel of structurally varied compounds were designed and synthesised using Henry Knoevenagel condensation reactions. Single crystal X-Ray analysis confirmed the E configuration for six examples of these novel structures. A number of nitrostyrene-related compounds were also investigated including 1,3-bis(aryl)-2-nitropropenes together with heterocyclic scaffolds containing the nitrovinyl pharmacophore such as 3-nitro-2-phenyl-2H-chromenes. The antiproliferative activities of the compounds were evaluated using the BL cell lines EBV- MUTU-1 and EBV+ DG- 75 (chemoresistant) to establish preliminary structure-activity relationships. Results: Lead compounds with optimized nitrostyrene scaffolds and 3-nitro-2-phenyl-2Hchromene structures were successfully established with typical IC50 values of 0.45 μM and 0.47 μM in MUTU-1 cells and 1.41 μM and 1.92 μM, respectively, in DG-75 cells. The mechanism of cell death was identified as apoptotic and the lead compound was found to elicit comparable apoptotic effects to Taxol in Burkitt's lymphoma cell lines MUTU-1 and DG-75. Conclusion: This class of pharmaceutically active compounds with potential for the treatment of Burkitt's lymphoma suggest a potential role for nitrostyrene based agents in chemotherapy.

Background: Currently, used oral antiplatelet drugs are both limited and associated with the risk of treatment failure/resistance. Research in this area is hence highly desired. A series of xanthene-3-ones derivatives, we had synthesized, showed us that these derivatives had antiplatelet activity. As far as we know, no research on the effects of xanthen-3-ones in this area has been done. Objective: The aim was to study the antiplatelet potential of a series of synthesised 9-phenylxanthene- 3-ones and to find the ideal structural feature(s) for antiplatelet potential and determine the mechanism of action. Methods: The compounds were synthesized from 1,2,4-triacetoxybenzene and various benzaldehydes. The reaction proceeded smoothly under acidic alcoholic conditions, furnishing the desired products in good yields. The compounds were first screened in whole human blood where platelet aggregation was induced by arachidonic acid. Further analysis was targeted at search of the mechanism of action. Results: Initial screening showed that a majority of the synthesized derivatives had substantial antiplatelet potential. None of the compounds were able to block cyclooxygenase 1 or thromboxane synthase. The mechanism appeared to be based on antagonism of thromboxane effects. The most potent compound 9-(4'-dimethylaminophenyl)-2,6,7-trihydroxy-xanthene-3-one had better potential to block collagen induced platelet aggregation than clinically used acetylsalicylic acid. Conclusion: The last mentioned derivative is promising for further in vivo testing.