Biology subjects

Filgueiras-Rama, D.

Publications and source records attributed to Filgueiras-Rama, D..

3 recordsLinked to original sources

bioRxiv2026

Electrophysiological dependent antiarrhythmic drug response in population-based models of paroxysmal atrial fibrillation

Response to antiarrhythmic drugs varies markedly across patients with atrial fibrillation (AF), suggesting that treatment efficacy depends on the interaction between drug-specific mechanisms and patient-specific electrophysiological substrate. Here, we used population-based computational models to investigate how electrophysiological substrate and inter-individual ionic variability influence pharmacological efficacy and the underlying mechanisms. Two populations of human atrial models were generated from distinct substrates: a reference left atrial model and a second model incorporating inward-rectifier-enhancement (IRE) through a 2-fold increase in IK1 and IK,ACh. Both populations were independently calibrated against the same experimental datasets from patients with paroxysmal AF (pAF), yielding pAF and IRE-pAF populations. Sustained reentrant activity was induced in two-dimensional tissue simulations and subsequently used to assess cardioversion efficacy of flecainide, vernakalant and tertiapin-Q. Despite satisfying the same calibration criteria, IRE-pAF population exhibited a more arrhythmogenic phenotype: shorter refractoriness, higher dominant frequency (DF) and greater rotor stability. Antiarrhythmic efficacy markedly differed between substrates. Flecainide cardioversion decreased in IRE-pAF compared with pAF (34% vs 21%), whereas IK,ACh-targeting therapies preserved or improved efficacy in IRE-pAF (vernakalant: 41% vs 44%, tertiapin-Q: 11% vs 18%). Across drugs and substrates, rotor DF strongly influenced cardioversion outcome, with higher-frequency rotors showing lower termination rates. Drug-induced DF reduction emerged as a key mechanism associated with successful cardioversion, whereas effective refractory period (ERP) prolongation alone did not consistently explain treatment efficacy. In pAF, vernakalant achieved higher cardioversion efficacy than flecainide despite a smaller increase in ERP and greater DF reduction. Ionic analyses further showed that elevated IK,ACh favored responses to vernakalant and tertiapin-Q. These findings demonstrate that cardioversion efficacy emerges from the interaction between electrophysiological substrate, rotor dynamics and drug-specific mechanisms. In particular, substrates differing in inward rectifier activity exhibit distinct response patterns, while DF emerges as a robust marker of pharmacological susceptibility and a potential guide for drug-mediated AF termination.

bioengineering↗

bioRxiv2024

Protein aggregation capture assisted profiling of the thiol redox proteome

Oxidative damage is critical in various diseases, including cardiovascular and neurological conditions. Thiol redox reactions, acting as oxidative stress sensors, influence protein structure and function. Redox proteomics based on differential alkylation of reduced and oxidized Cys forms using mass spectrometry enables comprehensive analysis of thiol redox status in cells and tissues. We introduce PACREDOX, an innovative redox proteomics approach based on the Protein Aggregation Capture (PAC) protocol and we demonstrate its compatibility with library free data-independent acquisition (DIA). PACREDOX reduces preparation time and costs compared to traditional methods, such as FASILOX, while maintaining thiol and proteome coverage. To enable library-free DIA, we corrected in silico spectral libraries in DIA-NN using experimental retention time data from beta-methylthiol-modified peptides. PACREDOX with DIA quantified 4,000 protein groups and [~]45,000 modified peptides in myocardial tissue from a porcine model of atrial fibrillation, including over 8,000 cysteine-containing peptides, 30% of which were reversibly oxidized. Benchmarking PACREDOX and DIA against FASILOX in a myocardial infarction model reflects the potential and efficiency of this methodology to study oxidative damage. Overall, PACREDOX offers a high-throughput, cost-effective strategy for thiol redox proteome analysis, compatible with label-free quantitative workflows.

systems biology↗

bioRxiv2021

MKK6 deficiency promotes cardiac dysfunction through MKK3-p38γ/δ-mTOR hyperactivation

Stress-activated p38 kinases control a plethora of functions and their dysregulation has been linked to development of steatosis, obesity, immune disorders and cancer. Therefore, they have been identified as potential targets for novel therapeutic strategies. There are four p38 family members (p38, p38{beta}, p38{gamma}, and p38{delta}) that are activated by MKK3 and MKK6. Here we demonstrate that lack of MKK6 reduces the life span in mice. Longitudinal study of cardiac function in Mkk6-/- mice showed that young mice have cardiac hypertrophy which progresses to cardiac dilatation and fibrosis with age. Mechanistically, lack of MKK6 blunts p38 activation while causing MKK3-p38{gamma}/{delta} hyperphosphorylation and increased mTOR signaling, resulting in cardiac hypertrophy. Cardiac hypertrophy in Mkk6-/- mice is reverted by knocking out either p38{gamma} or p38{delta}, or by inhibiting mTOR pathway with rapamycin. In conclusion, we have identified a key role for the MKK3/6-p38{gamma}/{delta} pathway in the development of cardiac hypertrophy, which has important implications for the clinical use of p38 inhibitors in the long-term treatment since they might result in cardiotoxicity. eLifes Review ProcesseLife works to improve the process of peer review so that it more effectively conveys the assessment of expert reviewers to authors, readers and other interested parties. In the future we envision a system in which research is first published as a preprint and the outputs of peer review are the primary way research is assessed, rather than journal title. Our editorial process produces two outputs: i) an assessment by peers designed to be posted alongside a preprint for the benefit of the readers; ii) detailed feedback on the manuscript for the authors, including requests for revisions and suggestions for improvement. Therefore we want to change how we construct and write peer reviews to make them useful to both authors and readers in a way that better reflects the work you put into reading and thinking about a paper. eLife reviews now have three parts: O_LIAn evaluation summary (in two or three sentences) that captures the major conclusions of the review in a concise manner, accessible to a wide audience. C_LIO_LIA public review that details the strengths and weaknesses of the manuscript before you, and discusses whether the authors claims and conclusions are justified by their data. C_LIO_LIA set of private recommendations for the authors that outline how you think the science and its presentation could be strengthened. C_LI All three sections will be used as the basis for an eLife publishing decision, which will, as always, be made after a consultation among the reviewers and editor. Each of the public reviews will be published (anonymously) alongside the preprint, together with a response from the authors if they choose. In the case of papers we reject after review, the authors can choose to delay posting until their paper has been published elsewhere. If this is your first time going through this new process, we ask that you take some time to read our Reviewer Guide, which discusses how we see each section will be used, what it should contain, and what we hope it accomplishes. And we remind you that, with the shift of reviews from private correspondence to public discourse, it is more important than ever that reviews are written in a clear and constructive manner appropriate for a public audience and mindful of the impact language choices might have on the authors.

molecular biology↗