Cytokines regulation of chemokine and chemokine receptor in relation to multiple sclerosis.

Expression of chemokines CXCL10 and CCL2 is elevated within inflammatory lesions in the central nervous system (CNS) of multiple sclerosis (MS) patients, particularly in astrocytes. These chemokines play a critical role in the recruitment of inflammatory cells into the CNS during inflammation. However, the cerebrospinal fluid of MS patients also shows high levels of CXCL10 at the time of relapse but by contrast CCL2 is decreased. In the present study, the mechanisms controlling the synthesis and release of these two chemokines in MS were assessed in vitro using primary human brain astrocytes isolated from MS and non-MS individuals. Pro-inflammatory cytokines (interleukin-1beta , tumour necrosis factor and interferon-gamma) increased the expression of both CCL2 and CXCL10 by astrocytes at the mRNA and protein level, as determined by real time PCR and enzyme linked immunosorbent assays (ELISA), respectively. CCL2 binding to astrocytes was then determined to evaluate any autocrine action on astrocytes in a single astrocyte preparation. CCL2 bound constitutively and following cytokine treatment. CCL2-binding was not the result of the interaction with its receptor since astrocytes did not express CCR2 on this astrocyte culture. CCR2-independent binding of CCL2 was confirmed by the absence of intracellular signalling, evidenced by the lack of calcium influx as well as of Erk and Akt phosphorylation, in CCL2-treated astrocytes. Even though astrocytes expressed CXCR3, similar negative results on calcium influx and downstream signalling pathways were observed for CXCL10. D6 chemokine decoy receptor expression was then assessed in vitro and in situ to further investigate the mechanism(s) of chemokine binding to astrocytes. Cultured astrocytes constitutively expressed the D6 decoy receptor at the mRNA and protein level, but levels were unchanged following cytokine treatment. D6 was expressed in situ in MS normal appearing white matter and in control brain tissue, at both the mRNA and protein level. D6 expression was detected on neurons and microglia but not astrocytes using imunohistochemical methods. Incubation of frozen brain sections with biotinylated CCL2 resulted in partial co-localisation with D6 staining.Altogether, these results suggest a role for astrocytes in regulating inflammation through synthesis and secretion of CCL2 and CXCL10. Subsequently, CCL2 binding to astrocytes, either by binding to D6 decoy receptor or by alternative mechanisms, may establish a chemokine gradient in the CNS, and direct the migration of leukocytes

Direct impact of COVID-19 by estimating disability-adjusted life years at national level in France in 2020

Background: The World Health Organization declared a pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), on March 11, 2020. The standardized approach of disability-adjusted life years (DALYs) allows for quantifying the combined impact of morbidity and mortality of diseases and injuries. The main objective of this study was to estimate the direct impact of COVID-19 in France in 2020, using DALYs to combine the population health impact of infection fatalities, acute symptomatic infections and their post-acute consequences, in 28 days (baseline) up to 140 days, following the initial infection. Methods: National mortality, COVID-19 screening, and hospital admission data were used to calculate DALYs based on the European Burden of Disease Network consensus disease model. Scenario analyses were performed by varying the number of symptomatic cases and duration of symptoms up to a maximum of 140 days, defining COVID-19 deaths using the underlying, and associated, cause of death. Results: In 2020, the estimated DALYs due to COVID-19 in France were 990 710 (1472 per 100 000), with 99% of burden due to mortality (982 531 years of life lost, YLL) and 1% due to morbidity (8179 years lived with disability, YLD), following the initial infection. The contribution of YLD reached 375%, assuming the duration of 140 days of post-acute consequences of COVID-19. Post-acute consequences contributed to 49% of the total morbidity burden. The contribution of YLD due to acute symptomatic infections among people younger than 70 years was higher (67%) than among people aged 70 years and above (33%). YLL among people aged 70 years and above, contributed to 74% of the total YLL. Conclusions: COVID-19 had a substantial impact on population health in France in 2020. The majority of population health loss was due to mortality. Men had higher population health loss due to COVID-19 than women. Post-acute consequences of COVID-19 had a large contribution to the YLD component of the disease burden, even when we assume the shortest duration of 28 days, long COVID burden is large. Further research is recommended to assess the impact of health inequalities associated with these estimates

Cytokines regulation of chemokine and chemokine receptor in relation to multiple sclerosis

Expression of chemokines CXCLIO and CCL2 is elevated within inflammatory lesions in the central nervous' system (CNS) of multiple sclerosis (MS) patients, particularly in astrocytes. These' chemokines play a critical role in the recruitment of inflammatory cells into the CNS during inflammation. However, the cerebrospinal fluid of MS patients also shows high levels of CXCLlO at the time of relapse but by contrast CCL2 is decreased. In the present study, the mechanisms controlling the synthesis and release of these two chemokines in MS were assessed in vitro using primary human brain astrocytes isolated from MS and non-MS individuals. Pro-inflammatory cytokines (interleukin -1f3 , tumour necrosis factor and interferon,) increased the expression of both CCL2 and CXCLIO by astrocytes at the mRNA and protein level, as determined by real time PCR and enzyme linked immunosorbent assays (ELISA), respectively. CCL2 binding to astrocytes was then determined to evaluate any autocrine action on astrocytes in a single astrocyte preparation. CCL2 bound constitutively and following cytokine treatment. CCL2-binding was not the result of the interaction with its receptor since astrocytes did not express CCR2 on this astrocyte culture. CCR2-independent binding of CCL2 was confirmed by the absence of intracellular signalling, evidenced by the lack of calcium influx as well as of Erk and Akt phosphorylation, in CCL2-treated astrocytes. Even though astrocytes expressed CXCR3, similar negative results on calcium influx and downstream signalling pathways were observed for CXCLlP. D6 chemokine decoy receptor expression was then assessed in vitro and in situ to further investigate the mechanism(s) of chemokine binding to astrocytes. Cultured astrocytes constitutively expressed the D6 decoy receptor at the mRN~ and· . protein level, but levels were unchanged following cytokine treatment. D6 was expressed in situ in MS normal appearing white matter and in control brain tissue, at both the mRNA and protein level. D6 expression was detected on neurons and microglia but not astrocytes using imunohistochemical methods. Incubation of frozen brain sections with biotinylated CCL2 resulted in partial co-localisation with D6 staining. Altogether, these results suggest a role for astrocytes in regulating inflammation through synthesis and secretion of CCL2 and CXCLIO. Subsequently, CCL2 binding to astrocytes, either by binding to D6 decoy receptor or by alternative mechanisms, may establish a chemokine gradient in the CNS, and direct the migration of leukocytes.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Management of superficial venous thrombosis in unevaluated situations: Cancer, severe renal impairment, pregnancy and post-partum

International audienceBackground Information is lacking as to the management of patients with superficial venous thrombosis (SVT) whose profile has been excluded from trials, such as patients with active cancer, severe renal impairment, or pregnancy. Objectives To describe the frequency and management of SVT occurring in these situations. Methods We retrospectively analyzed the frequency, management and evolution of all patients with isolated SVT associated with either active cancer, severe renal impairment, or pregnant or postpartum women, diagnosed in 2 university hospital between January 1st, 2015 and December 31st, 2016. Results Of the 594 isolated SVTs individualized from the 7941 reports screened, 149 SVTs (105 in the upper extremity, 44 in the lower extremity) were analyzed: 94 (63%) associated with active cancer, 27 (18%) with severe renal impairment and 30 (20%) pregnant or postpartum women. SVT was treated with anticoagulant in 34 (36%) patients with cancer, 3 (11%) patients with severe renal impairment and 19 (63%) pregnant or postpartum women. At 3-month, 16 patients (10.8%) had a further venous thromboembolic event, 8 (5.4%) major bleeding, and 9 (6.1%) died. Conclusion SVT in patients with active cancer, severe renal impairment and pregnant or postpartum women represents a quarter of isolated SVTs diagnosed. Heterogeneity of treatment patterns mainly affects patients with cancer and severe renal impairment. Poor outcomes, although probably linked to morbidity, call for dedicated research in these specific situations

Pharmacological Characterisation of Nicotinic Acetylcholine Receptors Expressed in Human iPSC-Derived Neurons.

Neurons derived from human induced pluripotent stem cells (iPSCs) represent a potentially valuable tool for the characterisation of neuronal receptors and ion channels. Previous studies on iPSC-derived neuronal cells have reported the functional characterisation of a variety of receptors and ion channels, including glutamate receptors, γ-aminobutyric acid (GABA) receptors and several voltage-gated ion channels. In the present study we have examined the expression and functional properties of nicotinic acetylcholine receptors (nAChRs) in human iPSC-derived neurons. Gene expression analysis indicated the presence of transcripts encoding several nAChR subunits, with highest levels detected for α3-α7, β1, β2 and β4 subunits (encoded by CHRNA3-CHRNA7, CHRNB1, CHRNB2 and CHRNB4 genes). In addition, similarly high transcript levels were detected for the truncated dupα7 subunit transcript, encoded by the partially duplicated gene CHRFAM7A, which has been associated with psychiatric disorders such as schizophrenia. The functional properties of these nAChRs have been examined by calcium fluorescence and by patch-clamp recordings. The data obtained suggest that the majority of functional nAChRs expressed in these cells have pharmacological properties typical of α7 receptors. Large responses were induced by a selective α7 agonist (compound B), in the presence of the α7-selective positive allosteric modulator (PAM) PNU-120596, which were blocked by the α7-selective antagonist methyllycaconitine (MLA). In addition, a small proportion of the neurons express nAChRs with properties typical of heteromeric (non-α7 containing) nAChR subtypes. These cells therefore represent a great tool to advance our understanding of the properties of native human nAChRs, α7 in particular

ER stress inhibits neuronal death by promoting autophagy

Endoplasmic reticulum (ER) stress has been implicated in neurodegenerative diseases but its relationship and role in disease progression remain unclear. Using genetic and pharmacological approaches, we showed that mild ER stress ("preconditioning") is neuroprotective in Drosophila and mouse models of Parkinson disease. In addition, we found that the combination of mild ER stress and apoptotic signals triggers an autophagic response both in vivo and in vitro. We showed that when autophagy is impaired, ER-mediated protection is lost. We further demonstrated that autophagy inhibits caspase activation and apoptosis. Based on our findings, we conclude that autophagy is required for the neuroprotection mediated by mild ER stress, and therefore ER preconditioning has potential therapeutic value for the treatment of neurodegenerative diseases

Pharmacological properties of nAChR ligands on iPSC-derived neurons.

<p>Data are means ± SEM of 3–5 independent experiments.</p><p>Pharmacological properties of nAChR ligands on iPSC-derived neurons.</p

Influence of temperature on potentiation of Compound B responses by PNU-120596.

<p>A) Representative FLIPR traces showing the change in fluorescence observed when compound B (1 μM) and PNU-120596 (100 μM) were co-applied to iPSC-derived neurons at room temperature (RT) (closed circles) and at 37°C (open circles). B) Concentration-response relationship of PNU-120596 in the presence of compound B (1 μM) at room temperature (RT) and at 37°C. Data points are means of 4 independent experiments each of which generated paired data from the same batch of cells incubated at two temperatures.</p

Potentiation and antagonism of nAChR agonist responses in iPSC neurons.

<p>(A) Representative of FLIPR traces produced with a range of compound B concentrations (0.3 nM—1 μM) in the presence of PNU-120596 (3 μM). Also shown are concentration-response curves for the agonists compound B (circles), epibatidine (triangles) and choline (squares), in the presence of PNU-120596 (3 μM) (B). Responses to compound B (1 μM) in the presence of PNU-120596 (3 μM) were blocked completely in a concentration-dependent manner by the α7-selective antagonist MLA (C). Data are means ± SEM of 3–5 independent experiments.</p