Dataset Information

Mechanism and site of action of big dynorphin on ASIC1a.

ABSTRACT: Acid-sensing ion channels (ASICs) are proton-gated cation channels that contribute to neurotransmission, as well as initiation of pain and neuronal death following ischemic stroke. As such, there is a great interest in understanding the in vivo regulation of ASICs, especially by endogenous neuropeptides that potently modulate ASICs. The most potent endogenous ASIC modulator known to date is the opioid neuropeptide big dynorphin (BigDyn). BigDyn is up-regulated in chronic pain and increases ASIC-mediated neuronal death during acidosis. Understanding the mechanism and site of action of BigDyn on ASICs could thus enable the rational design of compounds potentially useful in the treatment of pain and ischemic stroke. To this end, we employ a combination of electrophysiology, voltage-clamp fluorometry, synthetic BigDyn analogs, and noncanonical amino acid-mediated photocrosslinking. We demonstrate that BigDyn binding results in an ASIC1a closed resting conformation that is distinct from open and desensitized states induced by protons. Using alanine-substituted BigDyn analogs, we find that the BigDyn modulation of ASIC1a is primarily mediated through electrostatic interactions of basic amino acids in the BigDyn N terminus. Furthermore, neutralizing acidic amino acids in the ASIC1a extracellular domain reduces BigDyn effects, suggesting a binding site at the acidic pocket. This is confirmed by photocrosslinking using the noncanonical amino acid azidophenylalanine. Overall, our data define the mechanism of how BigDyn modulates ASIC1a, identify the acidic pocket as the binding site for BigDyn, and thus highlight this cavity as an important site for the development of ASIC-targeting therapeutics.

SUBMITTER: Borg CB

PROVIDER: S-EPMC7132280 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Mechanism and site of action of big dynorphin on ASIC1a.

Borg Christian B CB Braun Nina N Heusser Stephanie A SA Bay Yasmin Y Weis Daniel D Galleano Iacopo I Lund Camilla C Tian Weihua W Haugaard-Kedström Linda M LM Bennett Eric P EP Lynagh Timothy T Strømgaard Kristian K Andersen Jacob J Pless Stephan A SA

Proceedings of the National Academy of Sciences of the United States of America 20200312 13

Acid-sensing ion channels (ASICs) are proton-gated cation channels that contribute to neurotransmission, as well as initiation of pain and neuronal death following ischemic stroke. As such, there is a great interest in understanding the in vivo regulation of ASICs, especially by endogenous neuropeptides that potently modulate ASICs. The most potent endogenous ASIC modulator known to date is the opioid neuropeptide big dynorphin (BigDyn). BigDyn is up-regulated in chronic pain and increases ASIC- ...[more]

PMID: 32165542

Similar Datasets

Project description:Rheumatic Heart Disease (RHD) remains endemic in low- and middle-income countries (LMICs) despite its virtual elimination in high-income countries. RHD Action was launched to amplify global efforts to control RHD in 2015 by World Heart Federation and Reach, with demonstration projects in Uganda and Tanzania, and support from Medtronic Foundation. The Small Grants Programme focuses on three domains: People and Communities, Medicines and Technologies, and Systems and Services. It is designed to support patient and community groups in promoting awareness, advocacy, and to build health workers' capacity to prevent and treat RHD in LMICs. Our study evaluates the impact and effectiveness of the RHD Action Small Grants Programme. Methods: We conducted a mixed method study that involved both quantitative and qualitative surveys, through phone interviews and online surveys amongst the grant beneficiaries, to assess the impact and effectiveness of the small grant programme. An invitation to complete an online survey, using a Google Forms format, was issued to Small Grant Project Directors and Co-Directors that received funding for projects between 2017 and 2019. The online survey requested basic project information using tick boxes, Likert scales, and short answer open-ended questions about successes and challenges faced by recipients. The questionnaire also addressed recipients' experience with the RHD Action Small Grants process - applying for the grant, nature and quality of support received to carry out project, the reporting process, and any media coverage provided. For the phone interviews, responses to the short-answer questions were used as the basis for follow up phone interviews. The discussions were recorded, transcribed and thematically analysed for new and recurring themes emerging from the in-depth discussions. Initiated in 2017, RHD Action has funded 21 proposals from a pool of 60 submissions. Recipient countries include Zambia, Uganda (2), Namibia, Kenya, Malawi (2), Egypt, Ethiopia, Nigeria (3), Rwanda (2), Mozambique, and Cameroon (2) as well as Fiji (2), the Philippines and Nepal. Five recipients were funded in 2017, eight in 2018 and eight in 2019. Project directors are primarily junior doctors and project managers supervised by senior mentors. In most cases, this is their first funding award. These projects have demonstrated tangible impact and have provided content for first manuscript and abstract submissions and presentations at professional conferences. Grant reports are presented as website stories showcasing the achievements of small local efforts with meaningful impact. For RHD Action, there is large return on a modest monetary investment resulting in a very visible, viable global RHD networking platform for enthusiastic community and provider activists.

Dataset Information

Mechanism and site of action of big dynorphin on ASIC1a.

Publications

Mechanism and site of action of big dynorphin on ASIC1a.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets