Nitric oxide promotes cysteine N-degron proteolysis through control of oxygen availability.

Selected proteins containing an N-terminal cysteine (Nt-Cys) are subjected to rapid, O-dependent proteolysis via the Cys/Arg-branch of the N-degron pathway. Cysteine dioxygenation is catalyzed in mammalian cells by 2-aminoethanethiol dioxygenase (ADO), an enzyme that manifests extreme O sensitivity. The canonical substrates of this pathway in mammalia are the regulators of G-protein signaling 4, 5, and 16, as well as interleukin-32.

Making sense of oxygen sensing.

Homeostatic control of cellular oxygen availability is a crucial feature of all eukaryotic life, and central to this process is the ability to sense oxygen across a broad range of concentrations and time scales. Much of our understanding of the molecular mechanisms underpinning oxygen sensing has been obtained using cell culture models, yet the biophysical properties of oxygen combined with the complex nature of cellular O consumption can make the interpretation of such data difficult. In this commentary, we have outlined some of the main problems encountered in measuring and manipulating cell monolayer oxygenation in vitro, and contextualised them using both historical and contemporary examples.

Hif-2α programs oxygen chemosensitivity in chromaffin cells.

The study of transcription factors that determine specialized neuronal functions has provided invaluable insights into the physiology of the nervous system. Peripheral chemoreceptors are neurone-like electrophysiologically excitable cells that link the oxygen concentration of arterial blood to the neuronal control of breathing. In the adult, this oxygen chemosensitivity is exemplified by type I cells of the carotid body, and recent work has revealed one isoform of the hypoxia-inducible transcription factor (HIF), HIF-2α, as having a nonredundant role in the development and function of that organ.

N-terminal cysteine acetylation and oxidation patterns may define protein stability.

Oxygen homeostasis is maintained in plants and animals by O-sensing enzymes initiating adaptive responses to low O (hypoxia). Recently, the O-sensitive enzyme ADO was shown to initiate degradation of target proteins RGS4/5 and IL32 via the Cysteine/Arginine N-degron pathway. ADO functions by catalysing oxidation of N-terminal cysteine residues, but despite multiple proteins in the human proteome having an N-terminal cysteine, other endogenous ADO substrates have not yet been identified.

Paving the way for patient centricity in real-world evidence (RWE): Qualitative interviews to identify considerations for wider implementation of patient-reported outcomes in RWE generation.

Objectives: Real-world evidence (RWE) generation can be enhanced by including patient-reported outcomes (PROs). Methods for collecting and using PRO data in the real-world setting are currently underdeveloped and there is no international guidance specific to its use in this context. This study explored stakeholders' perspectives and needs for using PROs in RWE generation.

Comparative analysis of N-terminal cysteine dioxygenation and prolyl-hydroxylation as oxygen-sensing pathways in mammalian cells.

In animals, adaptation to changes in cellular oxygen levels is coordinated largely by 2-oxoglutarate-dependent prolyl-hydroxylase domain (PHD) dioxygenase family members, which regulate the stability of their hypoxia-inducible factor (HIF) substrates to promote expression of genes that adapt cells to hypoxia. Recently, 2-aminoethanethiol dioxygenase (ADO) was identified as a novel O-sensing enzyme in animals. Through N-terminal cysteine dioxygenation and the N-degron pathway, ADO regulates the stability of a set of non-transcription factor substrates; the regulators of G-protein signaling 4, 5.

Monitoring ADO dependent proteolysis in cells using fluorescent reporter proteins.

2-Aminoethanethiol dioxygenase (ADO) is the mammalian orthologue of the plant cysteine oxidases and together these enzymes are responsible for catalysing dioxygenation of N-terminal cysteine residues of certain proteins. This modification creates an N-degron motif that permits arginylation and subsequent proteasomal degradation of such proteins via the Arg-branch of the N-degron pathway. In humans 4 proteins have been identified as substrates of ADO; regulators of G-protein signalling (RGS) 4, 5 and 16, and interleukin-32 (IL-32).

Implementation of patient-reported outcome measures in real-world evidence studies: Analysis of ClinicalTrials.gov records (1999-2021).

Background: Real-world evidence (RWE) plays an increasingly important role within global regulatory and reimbursement processes. RWE generation can be enhanced by collecting and using patient-reported outcomes (PROs), which can provide valuable information on the effectiveness, safety, and tolerability of health interventions from the patient perspective. This analysis aims to examine and summarise the utilisation of patient-reported outcomes measures (PROMs) in real-world studies.

Systematic review of guidance for the collection and use of patient-reported outcomes in real-world evidence generation to support regulation, reimbursement and health policy.

Background: Real-world evidence (RWE) plays an increasingly important role within global regulatory and reimbursement processes. RWE generation can be enhanced by the collection and use of patient-reported outcomes (PROs), which can provide valuable information on the effectiveness, safety, and tolerability of health interventions from the patient perspective. This systematic review aims to examine and summarise the available PRO-specific recommendations and guidance for RWE generation.

Nitric oxide biosensor uncovers diminished ferrous iron-dependency of cultured cells adapted to physiological oxygen levels.

Iron is an essential metal for cellular metabolism and signaling, but it has adverse effects in excess. The physiological consequences of iron deficiency are well established, yet the relationship between iron supplementation and pericellular oxygen levels in cultured cells and their downstream effects on metalloproteins has been less explored. This study exploits the metalloprotein geNOps in cultured HEK293T epithelial and EA.

International perspectives on suboptimal patient-reported outcome trial design and reporting in cancer clinical trials: A qualitative study.

Purpose: Evidence suggests that the patient-reported outcome (PRO) content of cancer trial protocols is frequently inadequate and non-reporting of PRO findings is widespread. This qualitative study examined the factors influencing suboptimal PRO protocol content, implementation, and reporting, and use of PRO data during clinical interactions.

Methods: Semi-structured interviews were conducted with four stakeholder groups: (1) trialists and chief investigators; (2) people with lived experience of cancer; (3) international experts in PRO cancer trial design; (4) journal editors, funding panelists, and regulatory agencies.

Hypoxic and pharmacological activation of HIF inhibits SARS-CoV-2 infection of lung epithelial cells.

COVID-19, caused by the novel coronavirus SARS-CoV-2, is a global health issue with more than 2 million fatalities to date. Viral replication is shaped by the cellular microenvironment, and one important factor to consider is oxygen tension, in which hypoxia inducible factor (HIF) regulates transcriptional responses to hypoxia. SARS-CoV-2 primarily infects cells of the respiratory tract, entering via its spike glycoprotein binding to angiotensin-converting enzyme 2 (ACE2).

Development of a core outcome set for use in community-based bipolar trials-A qualitative study and modified Delphi.

Background: A core outcome set (COS) is a standardised collection of outcomes to be collected and reported in all trials within a research area. A COS can reduce reporting bias and facilitate evidence synthesis. This is currently unavailable for use in community-based bipolar trials.

Nrf2-regulated redox signaling in brain endothelial cells adapted to physiological oxygen levels: Consequences for sulforaphane mediated protection against hypoxia-reoxygenation.

Ischemic stroke is associated with a surge in reactive oxygen species generation during reperfusion. The narrow therapeutic window for the delivery of intravenous thrombolysis and endovascular thrombectomy limits therapeutic options for patients. Thus, understanding the mechanisms regulating neurovascular redox defenses are key for improved clinical translation.

CXCR2 antagonist for patients with chronic obstructive pulmonary disease with chronic mucus hypersecretion: a phase 2b trial.

Background: Oral CXC chemokine receptor 2 (CXCR2) antagonists have been shown to inhibit neutrophil migration and activation in the lung in preclinical and human models of neutrophilic airway inflammation. A previous study with danirixin, a reversible CXCR2 antagonist, demonstrated a trend for improved respiratory symptoms and health status in patients with COPD.

Methods: This 26-week, randomised, double-blind, placebo-controlled phase IIb study enrolled symptomatic patients with mild-to-moderate COPD at risk for exacerbations.

Conserved N-terminal cysteine dioxygenases transduce responses to hypoxia in animals and plants.

Organisms must respond to hypoxia to preserve oxygen homeostasis. We identify a thiol oxidase, previously assigned as cysteamine (2-aminoethanethiol) dioxygenase (ADO), as a low oxygen affinity (high- O) amino-terminal cysteine dioxygenase that transduces the oxygen-regulated stability of proteins by the N-degron pathway in human cells. ADO catalyzes the conversion of amino-terminal cysteine to cysteine sulfinic acid and is related to the plant cysteine oxidases that mediate responses to hypoxia by an identical posttranslational modification.

Systematic Evaluation of Patient-Reported Outcome Protocol Content and Reporting in Cancer Trials.

Background: Patient-reported outcomes (PROs) are captured within cancer trials to help future patients and their clinicians make more informed treatment decisions. However, variability in standards of PRO trial design and reporting threaten the validity of these endpoints for application in clinical practice.

Methods: We systematically investigated a cohort of randomized controlled cancer trials that included a primary or secondary PRO.

Defining Physiological Normoxia for Improved Translation of Cell Physiology to Animal Models and Humans.

The extensive oxygen gradient between the air we breathe (Po ~21 kPa) and its ultimate distribution within mitochondria (as low as ~0.5-1 kPa) is testament to the efforts expended in limiting its inherent toxicity. It has long been recognized that cell culture undertaken under room air conditions falls short of replicating this protection in vitro.

Patient-reported outcome measures used in patients with primary sclerosing cholangitis: a systematic review.

Background: Primary Sclerosing Cholangitis (PSC) is a rare chronic, cholestatic liver condition in which patients can experience a range of debilitating symptoms. Patient reported outcome measures (PROMs) could provide a valuable insight into the impact of PSC on patient quality of life and symptoms. A previous review has been conducted on the quality of life instruments used in liver transplant recipients.

Evaluation of patient-reported outcome protocol content and reporting in UK cancer clinical trials: the EPiC study qualitative protocol.

Introduction: Patient-reported outcomes (PROs) are increasingly included within cancer clinical trials. If appropriately collected, analysed and transparently reported, these data might provide invaluable evidence to inform patient care. However, there is mounting indication that the design and reporting of PRO data in cancer trials may be suboptimal.

Reduced SERCA activity underlies dysregulation of Ca homeostasis under atmospheric O levels.

Unregulated increases in cellular Ca homeostasis are a hallmark of pathophysiological conditions and a key trigger of cell death. Endothelial cells cultured under physiologic O conditions (5% O) exhibit a reduced cytosolic Ca response to stimulation. The mechanism for reduced plateau [Ca] upon stimulation was due to increased sarco/endoplasmic reticulum Ca ATPase (SERCA)-mediated reuptake rather than changes in Ca influx capacity.

Assessing the impact of healthcare research: A systematic review of methodological frameworks.

Background: Increasingly, researchers need to demonstrate the impact of their research to their sponsors, funders, and fellow academics. However, the most appropriate way of measuring the impact of healthcare research is subject to debate. We aimed to identify the existing methodological frameworks used to measure healthcare research impact and to summarise the common themes and metrics in an impact matrix.

A PP2A-mediated feedback mechanism controls Ca-dependent NO synthesis under physiological oxygen.

Intracellular O is a key regulator of NO signaling, yet most studies are conducted in atmospheric O levels, hyperoxic with respect to the physiologic milieu. We investigated NO signaling in endothelial cells cultured in physiologic (5%) O and stimulated with histamine or shear stress. Culture of cells in 5% O (>5 d) decreased histamine- but not shear stress-stimulated endothelial (e)NOS activity.

Measurement properties of patient-reported outcome measures (PROMs) used in adult patients with chronic kidney disease: A systematic review.

Background: Patient-reported outcome measures (PROMs) can provide valuable information which may assist with the care of patients with chronic kidney disease (CKD). However, given the large number of measures available, it is unclear which PROMs are suitable for use in research or clinical practice. To address this we comprehensively evaluated studies that assessed the measurement properties of PROMs in adults with CKD.