Association of NaV1.8 with lipid rafts in DRG sensory neurons

Voltage gated sodium channels (VGSCs) play a key role in the initiation and propagation of action potentials in neuronal cells. NaV1.8 is a Tetrodotoxin resistant VGSC expressed in nociceptors and underlies the majority of sodium currents during action potentials. Many studies have highlighted a key role of NaV1.8 in different pain pathways. Lipid rafts are microdomains of the plasma membrane highly enriched in cholesterol and sphingolipids characterised by unique physical features: a liquid ordered phase and the resistance to nonionic detergent at 4°C. Lipid rafts are thought to act as platforms on the membrane where proteins and lipids can be compartmentalised and functionally clustered. In the present study we investigated NaV1.8 sub-cellular localisation and explored the idea that it is associated with lipid rafts in nociceptors. We hypothesised that lipid rafts on primary sensory neurons act as a platform on the membrane where NaV1.8 can be trafficked and underlie action potentials generation. We demonstrated that NaV1.8 is associated with lipid rafts along the sciatic nerve ex vivo and in DRG neurons in vitro. We also found that NaV1.8 is distributed in clusters along the axons of DRG neurons in vitro and ex vivo. We investigated the functional meaning of NaV1.8-raft association by studying action potential propagation in sensory neurons, in response to mechanical and chemical stimulation, by calcium imaging. Disruption of the association between NaV1.8 and lipid rafts in cultured sensory neurons, by methyl-betacyclodextrin and 7-ketocholesterol, caused a reduction in the number of cells able to propagate action potentials. In addition, lipid raft depletion caused a remarkable reduction in the conduction velocity upon mechanical stimulation. These findings highlight the importance of the association between NaV1.8 and lipid rafts in the conduction of action potentials and could lead to new perspectives in the study of NaV1.8 trafficking and nociceptor excitability

Association between Tetrodotoxin Resistant Channels and Lipid Rafts Regulates Sensory Neuron Excitability

PubMed ID: 22870192This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Insight Report: COVID-19 Community Involvement - “Let’s Talk About…HIV Care”

This informal session led by the Patient Experience Research Centre (PERC), in collaboration with Positively UK, invited people living with, affected by, or working in HIV to share their experience, views, questions and concerns on accessing HIV care during COVID-19. The aim of the call was to gather feedback on specific areas to help guide a proposed qualitative (interview-based study) looking to explore experiences, specifically on: 1. Challenges and concerns in managing HIV care during COVID-19 2. Challenges in the provision of HIV care during COVID-19 3. Opportunities presented for HIV care during COVID-19 We also wished to inspire new ways to rapidly engage and involve communities remotely during a public health emergency, through strengthening partnerships with existing groups (in this case, Positively UK)

Report 14: Online community involvement in COVID-19 research & outbreak response: early insights from a UK perspective

The Patient Experience Research Centre (PERC) at Imperial College London is developing research to explore and understand people’s views about, experiences of and behavioural responses to the outbreak in the UK and elsewhere. To guide that effort and to help inform COVID-19 research and responses more broadly - for example in mathematical modelling and policy - PERC launched an online community involvement initiative that sought rapid, early insight from members of the public and aimed to establish a network for ongoing community engagement. Priority areas for COVID-19 research Vaccine development was considered the most urgent research priority for many respondents. Social studies exploring the public’s experiences, risk perceptions and behaviours during this outbreak were necessary and important according to 95% of the respondents. Such research could: Improve the way the current outbreak response is planned and implemented; Improve the way information and guidance is provided to and understood by the public; Optimise the support provided to communities and vulnerable groups; and Improve future outbreak preparedness. Other recommended areas of research included: Understanding the role of the media in influencing how people react and respond; Furthering our basic understanding of the virus – how it spreads, who it affects the most and why, and whether people achieve and maintain immunity after being infected; Critiquing the UK’s response to the pandemic against that of other countries; and Ensuring lessons can be learnt from this outbreak to better equip us for future outbreaks, and public health emergencies in general. Key unmet needs amongst communities The main challenges described by respondents were ineffective communication, including access to information and information overload; and conflicting guidance and misinformation. Respondents’ described feelings of concern, confusion and, in some cases, panic as a result of these communication and information challenges. Others shared their frustration that there was nowhere to post their concerns or questions. In addition, respondents expressed a need for more detailed and bespoke practical guidance about their risk and how best to prepare and protect themselves and their loved ones. Almost half (47%) wanted to hear about the latest research on the virus, and 45% wanted a dedicated internet portal where they could access the latest information and trusted guidance. Making information more accessible to different communities, including those who are not online and those who have English as a second language was also highlighted as a priority

Clustering of the K⁺ channel GORK of Arabidopsis parallels its gating by extracellular K⁺

GORK is the only outward-rectifying Kv-like K<sup>+</sup> channel expressed in guard cells. Its activity is tightly regulated to facilitate K<sup>+</sup> efflux for stomatal closure and is elevated in ABA in parallel with suppression of the activity of the inward-rectifying K<sup>+</sup> channel KAT1. Whereas the population of KAT1 is subject to regulated traffic to and from the plasma membrane, nothing is known about GORK, its distribution and traffic in vivo. We have used transformations with fluorescently-tagged GORK to explore its characteristics in tobacco epidermis and Arabidopsis guard cells. These studies showed that GORK assembles in puncta that reversibly dissociated as a function of the external K<sup>+</sup> concentration. Puncta dissociation parallelled the gating dependence of GORK, the speed of response consistent with the rapidity of channel gating response to changes in the external ionic conditions. Dissociation was also suppressed by the K<sup>+</sup> channel blocker Ba<sup>2+</sup>. By contrast, confocal and protein biochemical analysis failed to uncover substantial exo- and endocytotic traffic of the channel. Gating of GORK is displaced to more positive voltages with external K<sup>+</sup>, a characteristic that ensures the channel facilitates only K<sup>+</sup> efflux regardless of the external cation concentration. GORK conductance is also enhanced by external K<sup>+</sup> above 1 mM. We suggest that GORK clustering in puncta is related to its gating and conductance, and reflects associated conformational changes and (de)stabilisation of the channel protein, possibly as a platform for transmission and coordination of channel gating in response to external K<sup>+</sup>

The role of public involvement in the design of the first SARS-CoV-2 human challenge study during an evolving pandemic

High quality health care research must involve patients and the public. This ensures research is important, relevant and acceptable to those it is designed to benefit. The world’s first human challenge study with SARS-CoV-2 undertook detailed public involvement to inform study design despite the urgency to review and establish the study. The work was integral to the UK Research Ethics Committee review and approval of the study. Discussion with individuals from ethnic minorities within the UK population supported decision-making around the study exclusion criteria. Public review of study materials for consent processes led to the addition of new information, comparisons and visual aids to help volunteers consider the practicalities and risks involved in participating. A discussion exploring the acceptability of a human challenge study with SARS-CoV-2 taking place in the UK, given the current context of the pandemic, identified overall support for the study. Public concern for the wellbeing of trial participants, as a consequence of isolation, was identified. We outline our approach to public involvement and its impact on study design

Infection-related and -unrelated malignancies, HIV and the aging population

Funding Information: Conflicts of interest: JR reports personal fees from Abbvie, Bionor, BMS, Boehringer, Gilead, Merck, Janssen, Tobira, Tibotec and ViiV, outside the submitted work. OK has received honoraria, consultancy and/or lecture fees from Abbott, Gilead, GSK, Janssen, Merck, Tibotec and Viiv outside the submitted work. All other authors state no commercial or other associations that may pose a conflict of interest. Funding: Primary support for EuroSIDA is provided by the European Commission BIOMED 1 (CT94-1637), BIOMED 2 (CT97-2713), 5th Framework (QLK2-2000-00773), 6th Framework (LSHP-CT-2006-018632) and 7th Framework (FP7/2007?2013; EuroCoord n? 260694) programmes. Current support also includes unrestricted grants from Janssen R&D, Merck and Co. Inc., Pfizer Inc. and GlaxoSmithKline LLC. The participation of centres in Switzerland was supported by The Swiss National Science Foundation (Grant 108787). The authors have no financial disclosures to make. Author contributions: LS developed the project, analysed the data, and was responsible for writing the manuscript. ?HB and OK contributed to the study design and analysis, interpretation of the data and writing of the manuscript. JL proposed the project and contributed to the study design, ideas for analysis, interpretation of the data and writing of the manuscript. BL, PD, AC, JR, BK, JT and IK contributed to national coordination, study design and writing of the manuscript. AM supervised the project and contributed to the study design and analysis, interpretation of the data and writing of the manuscript. Publisher Copyright: © 2016 British HIV AssociationObjectives: HIV-positive people have increased risk of infection-related malignancies (IRMs) and infection-unrelated malignancies (IURMs). The aim of the study was to determine the impact of aging on future IRM and IURM incidence. Methods: People enrolled in EuroSIDA and followed from the latest of the first visit or 1 January 2001 until the last visit or death were included in the study. Poisson regression was used to investigate the impact of aging on the incidence of IRMs and IURMs, adjusting for demographic, clinical and laboratory confounders. Linear exponential smoothing models forecasted future incidence. Results: A total of 15 648 people contributed 95 033 person-years of follow-up, of whom 610 developed 643 malignancies [IRMs: 388 (60%); IURMs: 255 (40%)]. After adjustment, a higher IRM incidence was associated with a lower CD4 count [adjusted incidence rate ratio (aIRR) CD4 count < 200 cells/μL: 3.77; 95% confidence interval (CI) 2.59, 5.51; compared with ≥ 500 cells/μL], independent of age, while a CD4 count < 200 cells/μL was associated with IURMs in people aged < 50 years only (aIRR: 2.51; 95% CI 1.40–4.54). Smoking was associated with IURMs (aIRR: 1.75; 95% CI 1.23, 2.49) compared with never smokers in people aged ≥ 50 years only, and not with IRMs. The incidences of both IURMs and IRMs increased with older age. It was projected that the incidence of IRMs would decrease by 29% over a 5-year period from 3.1 (95% CI 1.5–5.9) per 1000 person-years in 2011, whereas the IURM incidence would increase by 44% from 4.1 (95% CI 2.2–7.2) per 1000 person-years over the same period. Conclusions: Demographic and HIV-related risk factors for IURMs (aging and smoking) and IRMs (immunodeficiency and ongoing viral replication) differ markedly and the contribution from IURMs relative to IRMs will continue to increase as a result of aging of the HIV-infected population, high smoking and lung cancer prevalence and a low prevalence of untreated HIV infection. These findings suggest the need for targeted preventive measures and evaluation of the cost−benefit of screening for IURMs in HIV-infected populations.publishersversionPeer reviewe