Biology subjects

Koay, Y. C.

Publications and source records attributed to Koay, Y. C..

4 recordsLinked to original sources

bioRxiv2025

Targeting Runx1 protects against heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a public health problem and an elusive illness for which there are few treatment options. HFpEF is a systemic condition with a broad phenotype including diastolic dysfunction, pulmonary oedema, exercise intolerance, and left ventricular (LV) hypertrophy, collectively resulting in enhanced morbidity and mortality. Master-regulator transcription factor RUNX1 has recently been identified as a mediator of pathological changes in many cardiac diseases, however its role in HFpEF was unknown. Here we show that inhibition of Runx1 limits adverse cardiac remodelling in a clinically relevant mouse model of HFpEF. Cardiomyocyte-specific tamoxifen-inducible Runx1-deficient mice with HFpEF are protected, with preservation of diastolic function, and attenuation of pulmonary oedema, exercise intolerance, and hypertrophy. Furthermore, targeting Runx1 in HFpEF by using gene transfer or small molecule inhibitors improves diastolic function, both in female and male mice. Overall, our research enhances our understanding of RUNX1 in cardiac disease and demonstrates a novel translational target for the treatment of HFpEF. Keywords: Heart failure with preserved ejection fraction, metabolic heart failure, diastolic dysfunction, hypertrophy, pulmonary oedema, exercise intolerance CLINICAL PERSPECTIVEHeart failure (HF) is a leading cause of death world-wide and traditionally divided into different subtypes according to cardiac ejection fraction (EF). In contrast to HF with reduced EF (HFrEF), there are limited treatment options for HF with preserved EF which is of considerable concern given that HFpEF is projected to become the dominant HF subtype in the future 1. RUNX1 has been demonstrated to play an important role in the development of many cardiac and non-cardiac diseases. As a result, the potential for RUNX1 inhibitors as therapeutic agents across various conditions has become increasingly evident. In this study we established the therapeutic potential of targeting RUNX1 in the context of HFpEF. Targeting RUNX1 in cardiomyocytes markedly attenuates the development of the HFpEF phenotype and therefore this novel translational therapeutic target has great potential to address one of the biggest challenges in cardiac research.

physiology↗

bioRxiv2025

Optimized protocols for commonly-used murine models of heart failure with preserved ejection fraction.

BackgroundHFpEF is a leading cause of death worldwide and clinically relevant preclinical models are required to identify new therapeutic targets. The most clinically representative murine models of heart failure with preserved ejection fraction (HFpEF) in common use include a "2-hit" model combining metabolic stress with hypertension (high-fat diet [HFD] + N(gamma)-nitro-L-arginine methyl ester [L-NAME]) and a "3-hit" model that includes age as an additional "hit" (age + HFD + deoxycorticosterone pivalate [DOCP]). However, both models have reproducibility challenges, and sub-strain and sex dependency. Here we optimize both preclinical models to overcome these challenges. MethodsIn this study we optimized both models: (1) The 2-hit model was optimised to reproduce HFpEF (defined as the induction and maintenance of obesity, hypertension, diastolic dysfunction, left ventricular hypertrophy, lung congestion, and exercise intolerance) in both C57BL/6N and 6J mice using increasing L-NAME doses (0.5 g/L to 1.75 g/L) and protocol lengths (7 weeks to 13 weeks); and (2) The 3-hit model used 12-week-old C57BL/6N and 6J mice and two aging protocols were compared: HFD for 7 months, or healthy chow for 5 months then high fat diet for 7 months. After HFD, mice received an intraperitoneal injection of DOCP to induce hypertension via sodium retention. To enhance and prolong the effect of DOCP, mice received 1% NaCl drinking water at the time of injection until sacrifice, henceforth called "4-hit". To ensure the phenotype was maintained, a second bolus of DOCP was administered 8 weeks after the first. ResultsFor the 2-hit protocol, HFpEF was successfully induced in C57BL/6J mice when exposed to a 13-week L-NAME protocol with gradually increasing dosage from 1.0 g/L to 1.75 g/L. C57BL/6N mice showed the desired parameters after 7-weeks of 0.5 g/L L-NAME, which were not augmented by increased dosage or time administered. For the 4-hit mice, after addition of 1% NaCl drinking water following DOCP administration, a clear HFpEF phenotype was observed in C57BL/6N and 6J mice in both male and females, and maintained for up to 12 weeks. ConclusionsOur modifications ensure the 2-hit model is equally effective in both commonly used J and N substrains of C57BL/6 mice. Our 4-hit model overcomes the challenges of the 3-hit model, enhances reproducibility and robustness, which we demonstrate across sexes and substrains. Both of these new protocols will enhance clinically relevant mechanistic studies on HFpEF.

physiology↗

bioRxiv2022

Anabolic Factors and Myokines Improve Differentiation of Human Embryonic Stem Cell Derived Skeletal Muscle Cells

Skeletal muscle weakness is linked to many adverse health outcomes. Current research to identify new drugs has often been inconclusive due to lack of adequate cellular models. We have previously developed a scalable monolayer system to differentiate human embryonic stem cell (hESC) into mature skeletal muscle cells (SkMC) within 26 days without cell sorting or genetic manipulation. Here, building on our previous work, we show that differentiation and fusion of myotubes can be further enhanced using the anabolic factors testosterone (T) and follistatin (F) in combination with a cocktail of myokines (C). Importantly, combined TFC treatment significantly enhanced both hESC-SkMC fusion index and expression of various skeletal muscle markers including the motor protein Myosin Heavy Chain (MyHC). Transcriptomic and proteomic analysis revealed oxidative phosphorylation as the most up-regulated pathway and a significantly higher level of ATP and increased mitochondrial mass were also observed in TFC-treated hESC-SkMCs, suggesting enhanced energy metabolism is coupled to improved muscle differentiation. This cellular model will be a powerful tool for studying in vitro myogenesis and for drug discovery to further enhance muscle development or treat muscle diseases.

cell biology↗

bioRxiv2020

hRUV: Hierarchical approach to removal of unwanted variation for large-scale metabolomics data

Liquid chromatography-mass spectrometry based metabolomics studies are increasingly applied to large population cohorts, running for several weeks to months, even extending to years of data acquisition. This inevitably introduces unwanted intra- and inter-batch variations over time that can overshadow true biological signals and thus hinder potential biological discoveries. To date, normalization approaches have struggled to mitigate the variability introduced by technical factors whilst preserving biological variance, especially for protracted acquisitions. Here, we designed an experiment with an arrangement to embed biological sample replicates to measure the variance within and between batches for over 1,000 human plasma samples run over 44 days. We integrate these replicates in a novel workflow to remove unwanted variation in a hierarchical structure (hRUV) by progressively merging the adjustments in neighbouring batches. We demonstrate significant improvement of hRUV over existing methods in maintaining biological signals whilst removing unwanted variation for large scale metabolomics studies.

bioinformatics↗