Type I Interferon Drives Dendritic Cell Apoptosis via Multiple BH3-Only Proteins following Activation by PolyIC In Vivo

BACKGROUND: DC are activated by pathogen-associated molecular patterns (PAMPs), and this is pivotal for the induction of adaptive immune responses. Thereafter, the clearance of activated DC is crucial to prevent immune pathology. While PAMPs are of major interest for vaccine science due to their adjuvant potential, it is unclear whether and how PAMPs may affect DC viability. We aimed to elucidate the possible apoptotic mechanisms that control activated DC lifespan in response to PAMPs, particularly in vivo. METHODOLOGY/PRINCIPAL FINDINGS: We report that polyinosinic:polycytidylic acid (PolyIC, synthetic analogue of dsRNA) induces dramatic apoptosis of mouse splenic conventional DC (cDC) in vivo, predominantly affecting the CD8α subset, as shown by flow cytometry-based analysis of splenic DC subsets. Importantly, while Bim deficiency conferred only minor protection, cDC depletion was prevented in mice lacking Bim plus one of three other BH3-only proteins, either Puma, Noxa or Bid. Furthermore, we show that Type I Interferon (IFN) is necessary and sufficient for DC death both in vitro and in vivo, and that TLR3 and MAVS co-operate in IFNß production in vivo to induce DC death in response to PolyIC. CONCLUSIONS/SIGNIFICANCE: These results demonstrate for the first time in vivo that apoptosis restricts DC lifespan following activation by PolyIC, particularly affecting the CD8α cDC subset. Such DC apoptosis is mediated by the overlapping action of pro-apoptotic BH3-only proteins, including but not solely involving Bim, and is driven by Type I IFN. While Type I IFNs are important anti-viral factors, CD8α cDC are major cross-presenting cells and critical inducers of CTL. We discuss such paradoxical finding on DC death with PolyIC/Type I IFN. These results could contribute to understand immunosuppression associated with chronic infection, and to the optimization of DC-based therapies and the clinical use of PAMPs and Type I IFNs

Using C. elegans to discover therapeutic compounds for ageing-associated neurodegenerative diseases

Age-associated neurodegenerative disorders such as Alzheimer’s disease are a major public health challenge, due to the demographic increase in the proportion of older individuals in society. However, the relatively few currently approved drugs for these conditions provide only symptomatic relief. A major goal of neurodegeneration research is therefore to identify potential new therapeutic compounds that can slow or even reverse disease progression, either by impacting directly on the neurodegenerative process or by activating endogenous physiological neuroprotective mechanisms that decline with ageing. This requires model systems that can recapitulate key features of human neurodegenerative diseases that are also amenable to compound screening approaches. Mammalian models are very powerful, but are prohibitively expensive for high-throughput drug screens. Given the highly conserved neurological pathways between mammals and invertebrates, Caenorhabditis elegans has emerged as a powerful tool for neuroprotective compound screening. Here we describe how C. elegans has been used to model various human ageing-associated neurodegenerative diseases and provide an extensive list of compounds that have therapeutic activity in these worm models and so may have translational potential

Maintaining quality of life in multiple sclerosis: fact, fiction, or limited reality? Mantendo a qualidade de vida na esclerose múltipla: fato, ficção ou realidade circunscrita?

Health-related quality of life (HRQOL) is an important marker for health-related impacts on individuals with chronic diseases. This HRQOL study compares multiple sclerosis (MS) patients to a socio-demographically-matched healthy control group. HRQOL was assessed by means of a modular instrument (DEFU/DEFIS), which allows comparisons between diseased and healthy individuals. Main goal of the study was to obtain pertinent data to build a more reliable theoretical framework concerning HRQOL in MS. Another aim was to test the hypothesis of the so-called happiness paradox, according to which disabled individuals could maintain reasonable levels of HRQOL. Results show that MS individuals present lower levels of HRQOL in comparison to healthy controls, arguing against the happiness paradox hypothesis. Preservation of HRQOL levels against certain levels of disability may be restricted to a group of patients.<br>A qualidade de vida relacionada à saúde (QVRS) é um indicador importante do impacto das doenças crônicas sobre a vida dos indivíduos. Esse estudo propõe uma comparação da qualidade de vida de uma amostra de portadores de esclerose múltipla (EM) e uma amostra pareada de indivíduos saudáveis, avaliada pelos questionários DEFU / DEFIS. O objetivo é contribuir para a construção de um referencial teórico a respeito do impacto das doenças crônicas e de seus tratamentos no bem-estar dos pacientes, assim como de investigar a hipótese do paradoxo da felicidade, segundo a qual os pacientes manteriam um bom nível de sensação de bem-estar apesar de suas incapacidades causadas pela doença. Os resultados mostraram que pacientes com EM apresentam graus mais baixos de QVRS do que indivíduos sadios, o que não corrobora a existência do paradoxo da felicidade. No entanto, é possível que a preservação da QVRS apesar das vicissitudes associadas à doença possa ser restrita a um grupo de pacientes

Comparison of DNA-Hydrolyzing Antibodies from the Cerebrospinal Fluid and Serum of Patients with Multiple Sclerosis

It was found that high-affinity anti-DNA antibodies were one of the major components of the intrathecal IgG response in multiple sclerosis (MS) patients [Williamson et al., PNAS, 2001]. Recently we have shown that IgGs from the sera of MS patients are active in the hydrolysis of DNA. Here we have shown, for the first time, that average concentration of total proteins (132-fold), total IgGs (194-fold) and anti-DNA antibodies (200-fold) in the sera is significantly higher than that in the cerebrospinal fluid (CSF) of fifteen MS patients. The relative activities of total protein from sera and CSFs varied remarkably from patient to patient. It was surprising that the specific DNase activity of the total protein of CSF reparations were 198-fold higher than the serum ones. Electrophoretically and immunologically homogeneous IgGs were obtained by sequential affinity chromatography of the CSF proteins on protein G-Sepharose and FPLC gel filtration. We present first evidence showing that IgGs from CSF not only bind but efficiently hydrolyze DNA and that average specific DNase activity of homogeneous antibodies from CSF is unpredictably ∼49-fold higher than that from the sera of the same MS patients. Some possible reasons of these findings are discussed. We suggest that DNase IgGs of CSF may promote important neuropathologic mechanisms in this chronic inflammatory disorder and MS pathogenesis development