99 research outputs found
Functional Roles of Peroxisome Proliferator-Activated Receptor β/δ in a Model of Relapsing-Remitting Experimental Autoimmune Encephalomyelitis
No full textMultiple sclerosis (MS) is a chronic neurodegenerative disease characterized by lesions that form within the central nervous system which induce symptoms such as muscle weakness and paralysis. Many aspects of MS, ranging from causation to immunopathology, are currently under investigation as little is known of the factors that contribute to and exacerbate this disease. Presently, evidence suggests MS to be an inflammatory disease mediated by an autoimmune response to an unknown antigen. Results from clinical studies as well as animal models such as experimental autoimmune encephalomyelitis (EAE) suggest MS is initiated and maintained by immune cells such as Th1 lymphocytes. As a result, therapeutics prescribed to MS patients’ focus on modulating the inflammatory response so as to minimize myelin loss and CNS damage. Peroxisome proliferator-activated receptors (PPARs) are a family of transcription factors that show promise as potential targets for MS therapeutics. The PPAR sub-types, PPARα and PPARγ, have been shown to inhibit the propagation of inflammatory pathways and decrease the activity of pro-inflammatory cells in a number of inflammation driven diseases including rheumatoid arthritis and atherosclerosis. The anti-inflammatory role of PPARβ/δ is less well known, although preliminary studies suggest activation of this receptor may potentiate the activity of other transcription factors involved in inhibiting inflammatory pathways. As the PPAR family of transcription factors exhibit similar functions, it is hypothesized that the PPARβ/δ sub-type may have immunomodulatory effects that are comparable and complimentary to PPARα and –γ. This thesis describes a novel model of relapsing-remitting EAE (RR-EAE) that presents a disease course where EAE relapses are followed by periods of recovery that are characterized by the absence of clinical symptoms. Furthermore, a therapeutic intervention study carried out using this model demonstrates that the PPARγ agonist pioglitazone can decrease the severity of a relapse episode when drug treatment begins prior to a predicted relapse event. The inhibition of immune cell infiltration into the CNS and decreased immune cell activity mediated by pioglitazone, suggests that this ligand modulates the immune response. These results indicate that pioglitazone may be an effective treatment for relapsing-remitting MS. To examine the role of PPARβ/δ in RR-EAE and explore its effect on the activity of inflammatory cells, PPARβ/δ knockout mice were used due to the current lack of specific antagonists for this receptor. PPARβ/δ wild-type mice developed RR-EAE when immunized using protocol intended to induce this disease course. PPARβ/δ knockout mice however, developed chronic EAE when immunized in the same manner. Consistent with sustained clinical symptoms, CNS immune cell infiltration and activity was maintained throughout the disease in PPARβ/δ knockout mice. In contrast, the presence of immune cells within the CNS and consequent activity fluctuated according to the relapse and recovery pattern of disease in PPARβ/δ wild-type mice. PPARβ/δ appears to modulate inflammation by potentiating the apoptosis of activated T cells. Therefore, PPARβ/δ agonists may be potential candidates for MS treatment
Peripheral neural targets in obesity
No full textInterest in pharmacological treatments for obesity that act in the brain to reduce appetite has increased exponentially over recent years, but failures of clinical trials and withdrawals due to adverse effects have so far precluded any success. Treatments that do not act within the brain are, in contrast, a neglected area of research and development. This is despite the fact that a vast wealth of molecular mechanisms exists within the gut epithelium and vagal afferent system that could be manipulated to increase satiety. Here we discuss mechano- and chemosensory pathways from the gut involved in appetite suppression, and distinguish between gastric and intestinal vagal afferent pathways in terms of their basic physiology and activation by enteroendocrine factors. Gastric bypass surgery makes use of this system by exposing areas of the intestine to greater nutrient loads resulting in greater satiety hormone release and reduced food intake. A non-surgical approach to this system is preferable for many reasons. This review details where the opportunities may lie for such approaches by describing nutrient-sensing mechanisms throughout the gastrointestinal tract.Amanda J Page, Erin Symonds, Madusha Peiris, L Ashley Blackshaw and Richard L Youn
T Cell responses to whole SARS Coronavirus in humans
No full textEffective vaccines should confer long-term protection against future outbreaks of severe acute respiratory syndrome (SARS) caused by a novel zoonotic coronavirus (SARS-CoV) with unknown animal reservoirs. We conducted a cohort study examining multiple parameters of immune responses to SARS-CoV infection, aiming to identify the immune correlates of protection. We used a matrix of overlapping peptides spanning whole SARS-CoV proteome to determine T cell responses from 128 SARS convalescent samples by ex vivo IFN-γ ELISPOT assays. Approximately 50% of convalescent SARS patients were positive for T cell responses, and 90% possessed strongly neutralizing Abs. Fifty-five novel T cell epitopes were identified, with spike protein dominating total T cell responses. CD8+ T cell responses were more frequent and of a greater magnitude than CD4+ T cell responses (p < 0.001).
Polychromatic cytometry analysis indicated that the virus-specific T cells from the severe group tended to be a central memory phenotype (CD27+/CD45RO+) with a significantly higher frequency of polyfunctional CD4+ T cells producing IFN-γ, TNF-α, and IL-2, and CD8+ T cells producing IFN-γ, TNF-α, and CD107a (degranulation), as compared with the mild-moderate group. Strong T cell responses correlated significantly (p < 0.05) with higher neutralizing Ab. The serum cytokine profile during acute infection indicated a significant elevation of innate immune responses. Increased Th2 cytokines were observed in patients with fatal infection. Our study provides a roadmap for the immunogenicity of SARS-CoV and types of immune responses that may be responsible for the virus clearance, and should serve as a benchmark for SARS-CoV vaccine design and evaluation
Tu1923 - Multiple Nutrient Stimulation Enhances Enteroendocrine Cell Responses in Human and Mouse Colon
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Inaction and Impunity: Incidents of Religious Violence Targeting Christians, Muslims and Hindus (2015-2019)
No full text45p. The study is based on information provided by the National Christian Evangelical Alliance of Sri Lanka (NCEASL). It was compiled by Media Team of Verité Research. Mahoshadi Peiris was the lead researcher and author of the study. The team comprised of Mihindu Perera and Jonathan Cruse.Ethno-religious violence in Sri Lanka is a chronic and systemic problem that has continued despite successive changes in government. This study examines the key trends of incidents of violence faced by minority Christian, Muslim and Hindu groups in Sri Lanka between 2015 and 2019.
In 2015, the National Christian Evangelical Alliance of Sri Lanka and Verité Research released Silent Suppression: Restrictions on Religious Freedoms of Christians 1994-2004, a 20-year trend analysis report on ethno-religious violence.
This study build on that previous report by analysing 397 incidents of Freedom of Religion or Belief (FoRB) violations against Christians, multiple incidents of anti-Muslim riots, and discrimination against Hindu communities in the Northern and Eastern Provinces.
The findings of the study highlight a concerning trend of increased involvement of state officials as both active and passive actors in violations against minority communities. Moreover, the study finds that religious violence is sustained invariably through the action or inaction of the state
The presence of 5-HT in myenteric varicosities is not due to uptake of 5-HT released from the mucosa during dissection: use of a novel method for quantifying 5-HT immunoreactivity in myenteric ganglia
No full textAuthor version made available according to Publisher copyright policy. This is the accepted version of the following article:
Keating, D. J., Peiris, H., Kyloh, M., Brookes, S. J. H. and Spencer, N. J. (2013), The presence of 5-HT in myenteric varicosities is not due to uptake of 5-HT released from the mucosa during dissection: use of a novel method for quantifying 5-HT immunoreactivity in myenteric ganglia. Neurogastroenterology & Motility, 25: 849–853,
which has been published in final form at
http://dx.doi.org/10.1111/nmo.12189.
In addition, authors may also transmit, print and share copies with colleagues, provided that there is no systematic distribution of the submitted version, e.g. posting on a listserve, network or automated delivery
GPR84 in physiology—Many functions in many tissues
No full textMembers of the GPCR superfamily have a wide variety of physiological roles and are therefore valuable targets for developing effective medicines. However, within this superfamily are receptors that are less well characterized and remain orphans, including GPR84. This receptor is stimulated by ligands derived from dietary nutrients, specifically medium chain fatty acids (C9-14), and novel synthetic agonists. There are data demonstrating the role of GPR84 in inflammatory pathways, in addition to emerging data suggesting a key role for GPR84 as a nutrient-sensing GPCR involved in metabolism by sensing energy load via nutrient exposure and subsequent signalling leading to modulation of food intake. Exploring GPR84 pharmacology, its localization and what drives its expression has revealed multiple roles for this receptor. Here, we will reflect on these various roles of GRP84 demonstrated thus far, primarily by exploring data from pre-clinical and clinical studies in various physiological systems, with a specific focus on the gastrointestinal tract
Cosmological parameter estimation using Very Small Array data out to ℓ= 1500
No full textWe estimate cosmological parameters using data obtained by the Very Small Array (VSA) in its extended configuration, in conjunction with a variety of other cosmic microwave background (CMB) data and external priors. Within the flat Λ cold dark matter (ΛCDM) model, we find that the inclusion of high-resolution data from the VSA modifies the limits on the cosmological parameters as compared to those suggested by the Wilkinson Microwave Anisotropy Probe (WMAP) alone, while still remaining compatible with their estimates. We find that Ωbh2= 0.0234+0.0012−0.0014, Ωdmh2= 0.111+0.014−0.016, h= 0.73+0.09−0.05, nS= 0.97+0.06−0.03, 1010AS= 23+7−3 and τ= 0.14+0.14−0.07 for WMAP and VSA when no external prior is included. On extending the model to include a running spectral index of density fluctuations, we find that the inclusion of VSA data leads to a negative running at a level of more than 95 per cent confidence ( nrun=−0.069 ± 0.032 ), something that is not significantly changed by the inclusion of a stringent prior on the Hubble constant. Inclusion of prior information from the 2dF galaxy redshift survey reduces the significance of the result by constraining the value of Ωm. We discuss the veracity of this result in the context of various systematic effects and also a broken spectral index model. We also constrain the fraction of neutrinos and find that fν < 0.087 at 95 per cent confidence, which corresponds to mν < 0.32 eV when all neutrino masses are equal. Finally, we consider the global best fit within a general cosmological model with 12 parameters and find consistency with other analyses available in the literature. The evidence for nrun < 0 is only marginal within this model
A model of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice for the characterisation of intervention therapies
No full textMultiple sclerosis (MS) and its different forms are Studied in the animal model experimental autoimmune encephalomyelitis (EAE). Relapsing-remitting MS. the most common form of the disease can be induced in mice where clinical symptoms fluctuate in severity over time. However. the animal model does not experience periods of recovery where clinical signs are absent, unlike the human disease. We have developed a novel model of relapsing-remitting EAE in C57BL/6 mice immunised with myelin oligodendrocyte glycoprotein (MOG) peptide and Quil A as adjuvant. These animals have relapses that are followed by periods of recovery, during which time the animals do not exhibit illness. Furthermore. administration of the PPAR gamma agonist pioglitazone prior to a predicted relapse prevents the expected development of symptoms in a dose-dependent fashion. Immune cell infiltration into white matter of the CNS and decreased production of inflammatory cytokine IFN-gamma in treated animals were also observed. Our model will be a valuable tool in assessing intervention therapies for RR-MS sufferers. (c) 2007 Elsevier B.V. All rights reserved
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