Inflammation, lesions & 'black holes'
Promising prevention method found(17/03/15)
Scientists at the Walter and Eliza Hall Institute in Australia have developed a new drug-like molecule which can halt inflammation and has shown promise in preventing the progression of MS, reports Business Insider Australia.
Dr Ueli Nachbur, Associate Professor John Silke, Associate Professor Guillaume Lessene, Professor Andrew Lew and colleagues say the molecule inhibits a key signal which triggers inflammation.
“Inflammation results when our immune cells release hormones called cytokines, which is a normal response to disease,” Dr Nachbur said. “However when too many cytokines are produced, inflammation can get out-of-control and damage our own body, all of which are hallmarks of immune or inflammatory diseases.”
To apply the brakes on this runaway immune response, institute researchers developed a small drug-like molecule called WEHI-345 that binds to and inhibits a key immune signalling protein called RIPK2. This prevents the release of inflammatory cytokines.
The molecule is seen as a great starting point for a drug discovery program which may one day lead to new treatments for MS and other inflammatory diseases.
The research is published in the journal Nature Communications.
Source: Business Insider Australia © 2007-2015 Allure Media (17/03/15)
Scientists have developed a new inhibitor for the treatment of inflammatory diseases. They have come up with a potent, selective, small-molecule inhibitor called MCC950. MCC950 is the inhibitor of NLRP3, a NOD-like receptor (NLR) family, pyrin domain–containing protein 3 inflammasome. NLRP3 inflammasome s a component of the inflammatory process, and its activation is pathogenic in conditions like multiple sclerosis, type 2 diabetes, Alzheimer’s disease and atherosclerosis.
The results have been published in Nature Medicine and could prove to be a therapy for various conditions in the future. MCC950 specifically inhibits only NLRP3 and not other inflammasomes. MCC950 reduced interleukin-1β (IL-1β) production in vivo and attenuated the severity of experimental autoimmune encephalomyelitis (EAE), a disease model of multiple sclerosis.
Dr. Rebecca Coll, from UQ’s Institute for Molecular Bioscience, said “Inflammatory diseases result when our immune system is unable to switch off and so causes chronic inflammation in the body. Current therapies for inflammatory diseases, such as asprin, ibuprofen and steroids, don’t work well in severe cases and are not targeted, which can limit their effectiveness and cause side-effects. We now know that MCC950 can block an important component of the immune response — an inflammasome called NLRP3 that ‘switches on’ inflammation in our immune cells.”
Researchers hope this development would help in treating patients diagnosed with Cryopyrin-Associated Periodic Syndromes (CAPS), a family of rare and severe autoinflammatory diseases caused by a genetic mutation to NLRP3. Professor Luke O’Neill, Co-author and from Trinity College Dublin said, “We are excited about MCC950, which we believe has real potential to benefit patients suffering from several highly debilitating diseases, where there is a dire need for new medicines.”
Source: biotechin.asia (16/03/15)
Six Case Western Reserve scientists are part of an international team that has discovered two compounds that show promise in decreasing inflammation associated with diseases such as ulcerative colitis, arthritis and multiple sclerosis. The compounds, dubbed OD36 and OD38, specifically appear to curtail inflammation-triggering signals from RIPK2 (serine/threonine/tyrosine kinase 2). RIPK2 is an enzyme that activates high-energy molecules to prompt the immune system to respond with inflammation. The findings of this research appear in the Journal of Biological Chemistry.
"This is the first published indication that blocking RIPK2 might be efficacious in inflammatory disease," said senior author Derek Abbott, MD, PhD, associate professor of pathology, Case Western Reserve University School of Medicine. "Our data provides a strong rationale for further development and optimization of RIPK2-targeted pharmaceuticals and diagnostics."
In addition to Abbott and his medical school colleagues, the research team included representatives of Oncodesign, a therapeutic molecule biotechnology company in Dijon, France; Janssen Research & Development, a New Jersey-based pharmaceutical company; and Asclepia Outsourcing Solutions, a Belgium-based medicinal chemistry company.
The normal function of RIPK2 is to send warning signals to cells that bacterial infection has occurred, which in turn spurs the body to mobilize white blood cells. The white blood cells identify and encircle pathogens, which cause blood to accumulate in the region. It is this blood build-up that leads to the red and swollen areas characteristic of inflammation. When this process goes awry, the inflammation increases dramatically and tissue destruction ensues. RIPK2 works in conjunction with NOD1 and NOD2 (nucleotide-binding oligomerization domain) proteins in controlling responses by the immune system that lead to this inflammation process.
In this research project, investigators applied state-of-the-art genetic sequencing to learn the unique set of genes driven specifically by NOD2 proteins. They ultimately zeroed in on three specific NOD2-driven inflammation genes (SLC26a, MARCKSL1, and RASGRP1) that guided investigators in finding the most effective compounds.
Oncodesign searched its library of 4,000 compounds that targeted kinases, and after exhaustive study, narrowed the selection down to 13. Then investigators tested the 13 compounds in mouse and human cells and found that two compounds, OD36 and OD38, were most effective in blocking RIPK2.
"Based on the design of OD36 and OD38, we have developed with Oncodesign fifth-generation compounds that are even more effective than the first-generation OD36 and OD38," Abbott said. "Our next step is to seek a larger pharmaceutical company that can move these compounds forward into Phase 1 clinical trials in humans."
Source: News-Medical.Net Copyright 2000-2014 AZoM.com Limited (27/10/14)
Progressive multiple sclerosis CSF induces inflammatory demyelination, axonal loss, and astrogliosis in mice(15/08/14)
Cristofanilli M, Rosenthal H, Cymring B, Gratch D, Pagano B, Xie B, Sadiq SA.
Multiple sclerosis (MS) is an autoimmune disease characterised by inflammatory demyelination and neurodegeneration throughout the CNS, which lead over time to a condition of irreversible functional decline known as progressive MS.
Currently, there are no satisfactory treatments for this condition because the mechanisms that underlie disease progression are not well understood. This is partly due to the lack of a specific animal model that represents progressive MS.
We investigated the effects of intracerebroventricular injections of cerebrospinal fluid (CSF) derived from untreated primary progressive (PPMS), secondary progressive (SPMS), and relapsing/remitting (RRMS) MS patients into mice.
We found discrete inflammatory demyelinating lesions containing macrophages, B cell and T cell infiltrates in the brains of animals injected with CSF from patients with progressive MS. These lesions were rarely found in animals injected with RRMS-CSF and never in those treated with control-CSF.
Animals that developed brain lesions also presented extensive inflammation in their spinal cord. However, discrete spinal cord lesions were rare and only seen in animals injected with PPMS-CSF. Axonal loss and astrogliosis were seen within the lesions following the initial demyelination. In addition, Th17 cell activity was enhanced in the CNS and in lymph nodes of progressive MS-CSF injected animals compared to controls. Furthermore, CSF derived from MS patients who were clinically stable following therapy had greatly diminished capacity to induce CNS lesions in mice. Finally, we provided evidence suggesting that differential expression of pro-inflammatory cytokines present in the progressive MS CSF might be involved in the observed mouse pathology. Our data suggests that the agent(s) responsible for the demyelination and neurodegeneration characteristic of progressive MS is present in patient CSF and is amenable to further characterization in experimental models of the disease.
Source: Exp Neurol. 2014 Aug 8. pii: S0014-4886(14)00248-9. doi: 10.1016/j.expneurol.2014.07.020. [Epub ahead of print] & Pubmed PMID: 25111532 (15/08/14)
Physicians commonly measure multiple sclerosis (MS) disease activity based on the appearance of new T2-weighted hyperintense MRI lesions, which arise due to edema, inflammation, gliosis, and axonal loss. Given the nonspecific disease processes leading to these lesions and the often-mediocre correlation between T2 lesions and clinical outcomes, however, the search continues for a more specific tool that lends insight into MS pathophysiology and disease activity.
In recent years, increasing attention has been paid to the possibility of measuring chronic or persistent T1-weighted lesions that appear hypointense relative to normal-appearing white matter—lesions also known as “black holes”—as a means of gauging MS-associated neurodegeneration. This approach is supported by a considerable body of histopathological evidence indicating that chronic T1 black holes reflect irreversible demyelination and axonal loss.1
“In general, knowledge of the spatial localisation and time evolution of T1-weighted lesions may help resolve some mysterious aspects of MS, which remains a largely unresolved pathology,” explained Khader M. Hasan, PhD, an Associate Professor of Radiology at the University of Texas Medical School at Houston, in an interview with MedPage Today.
Some consider the evolution of T1 lesions to be one of the most promising endpoints in phase 2 clinical trials of neuroprotective and reparative MS interventions.2 But despite this enthusiasm, a proven link between persistent black holes and clinical outcomes in MS remains elusive. Whereas a handful of studies have pinpointed a correlation between black hole volume and clinical disability as measured by the Expanded Disability Status Scale (EDSS), several others have failed to identify such ties.1
To shed more light on whether black holes can be utilised to measure clinically relevant disease progression over time, lead investigator Nicola De Stefano, MD, PhD, an Associate Professor of Neurology at the University of Siena, Italy, and his colleagues conducted a longitudinal MRI study among a small group of 57 patients with confirmed relapsing-remitting MS for an average of 5 years. The investigators obtained brain scans of patients in 2000-2001 and again 10 years later using the same MRI protocol, thus ensuring comparable image quality at both time points. The scans were then compared to evaluate how patients’ brain lesions evolved over time and the impact of these changes on long-term disability, as measured using the EDSS.3
The majority of patients—82%—experienced disease relapse over the 10-year study period, and the average EDSS score for the total cohort worsened from 1.8±1.1 (mean [SD]) at baseline to 2.5±1.7 after 10 years (P<.001).3 In tandem, over the 10-year follow-up period mean T2 lesion volume increased from 5.8 ±6.4 to 8.3±8.1 cm3 (P<.001), and mean T1 lesion volume from 2.4±3.6 to 4.4±5 cm3 (P<.001).3
The investigators found that the long-term change in EDSS score was linked to the number of new and enlarging T1 and T2 lesions, as well as to increasing lesion volume. Notably, stepwise multiple regression analysis revealed that EDSS-measured declines in clinical disability best correlated with the combined measure of baseline T1 lesion count and increase in T1 lesion volume over time.3 Together, these factors explained 37% of the variability in worsening of the EDSS score over 10 years.3
“The finding in our study that the number of black holes at baseline and their volume increase over time were the only significant brain lesion correlates of EDSS worsening over 10 years highlights the role of neurodegeneration in the pathophysiology of long-term disability in MS,” wrote Dr. De Stefano and colleagues about their results, published in the Multiple Sclerosis Journal.3
Despite these findings, Dr. Hasan still views the relationship between T1 black holes and clinical measures of disease activity as tenuous. “Yes, black hole lesions are important, but other lesion types are also important. The lesion-centered approach in MS has not provided breakthrough insights into the pathogenesis of MS, as most MS lesions remain asymptomatic,” he commented.
One of Dr. Hasan’s biggest criticisms of the study is that the investigators provided no analysis of the possible effect of therapy. Fifty of the 57 patients received disease-modifying therapy during the study period, which makes it difficult to ascertain if and how much lesion evolution was influenced by the presence of treatment and the specific type of treatment.3 Phase 3 clinical studies that measure T1 black hole evolution may provide a deeper understanding of the ongoing disease process in MS and the possible effects of treatment.
These criticisms aside, Robert T. Naismith, MD, an Assistant Professor of Neurology at Washington University School of Medicine in St. Louis, believes that the findings from the recent Italian MRI study increase our understanding of T1 black holes in MS and may help inform treatment decisions. “The presence of black holes at baseline or their appearance during treatment should be one of several factors in predicting risk and may tip the decision toward either a first-line therapeutic with relatively high efficacy, or increased monitoring if an agent is chosen based primarily on established safety,” Dr. Naismith stated in a commentary on this study published last August in NEJM Journal Watch.4
1 Sahraian MA, Radue EW, Haller S, et al. Black holes in multiple sclerosis: definition, evolution, and clinical correlations. Acta Neurol Scand. 2010;122:1-8.
2 Barkhof F, Calabresi PA, Miller DH, et al. Imaging outcomes for neuroprotection and repair in multiple sclerosis trials. Nat Rev Neurol. 2009;5:256-266.
3 Giorgio A, Stromillo ML, Bartolozzi ML, et al. Relevance of hypointense brain MRI lesions for long-term worsening of clinical disability in relapsing multiple sclerosis. Mult Scler. 2014;20:214-219.
4 Naismith RT. “Black holes” and long-term disability in multiple sclerosis. NEJM Journal Watch. http://www.jwatch.org/na31801/2013/08/05/black-holes-and-long-term-disability-multiple-sclerosis. Published August 5, 2013. Accessed March 25, 2014.
Source: Medpage Today © 2014 Everyday Health Media, LLC (19/06/14)