Biology subjects

Ruskoaho, H.

Publications and source records attributed to Ruskoaho, H..

5 recordsLinked to original sources

bioRxiv2026

Patient-Derived hiPSC-Cardiomyocytes and Engineered Heart Tissues Reveal Distinct Functional Phenotypes in Inherited Cardiomyopathies

Background Hypertrophic and dilated cardiomyopathies (HCM and DCM) are the most common inherited cardiomyopathies. However, genotype-specific molecular and functional cardiomyocyte phenotypes and responses to neurohormonal stimulation remain incompletely understood. Here, we investigated whether patient-derived HCM and DCM cardiomyocytes exhibit distinct baseline phenotypes or differential responses to hypertrophic stimulation and pharmacological treatment. Methods Three human-induced pluripotent stem cell (hiPSC) lines were used: a control line, an HCM patient-derived line carrying a MYBPC3 mutation, and a DCM patient-derived line carrying an LMNA mutation. The cells were differentiated into hiPSC-cardiomyocytes, which were exposed to endothelin-1 and the GATA4-targeted compound 3i-1262, followed by transcriptional and protein expression analyses. In addition, engineered heart tissues (EHTs) were generated and cultured for 40 days, with endothelin-1 and 3i-1262 treatment applied during the final 20 days. Lastly, {beta}-adrenergic stimulation with isoprenaline was performed. EHT contractile function was quantified using MUSCLEMOTION. Results Patient-derived hiPSC-cardiomyocytes exhibited genotype-dependent responses to endothelin-1 at the transcriptional and protein levels. DCM-cardiomyocytes failed to maintain structural integrity in the EHTs, resulting in tissue fracture or cessation of beating. Functional analyses demonstrated distinct baseline contractile properties between control and cardiomyopathy EHTs, as well as differential responses to endothelin-1 and isoprenaline. Conclusions Patient-derived hiPSC-cardiomyocytes exhibit genotype-specific molecular and functional phenotypes. EHTs generated from HCM hiPSC-derived cardiomyocytes showed a progressive decline in apparent force, whereas DCM EHTs fractured over time, suggesting mutation-associated phenotypes in 3D cardiac tissue models. These findings highlight the utility of hiPSC-based cardiac models for investigating molecular and functional disease mechanisms and pharmacological responses in inherited cardiomyopathies. Keywords: hypertrophic cardiomyopathy, dilated cardiomyopathy, engineered heart tissues, hiPSC-derived cardiomyocytes, GATA4

pharmacology and toxicology↗

bioRxiv2025

The novel SCN5A-P1891A mutation is associated with left ventricular hypertrabeculation and links Nav1.5 to cardiomyocyte proliferation and disrupted 3D cardiac tissue formation

BackgroundLeft ventricular hypertrabeculation (LVHT) is a heterogenous cardiac condition with a complex and poorly understood aetiology. We comprehensively characterised the effect of a novel P1891A mutation in the SCN5A gene, which encodes the voltage-gated sodium channel Nav1.5, identified in a Finnish family diagnosed with LVHT. MethodsWe generated SCN5A-P1891A mutation-carrying human induced pluripotent stem cell-derived cardiomyocytes (P1891A-hiPSC-CMs) and performed electrophysiological assessments, including patch-clamp studies, and fluorescent calcium imaging, to determine the mutations effect on hiPSC-CM electrophysiology. We also evaluated the impact of the mutation on the proliferative capacity in response to mitogenic stimuli and on the hypertrophic response following cyclic mechanical stretch or endothelin-1 treatment. Further, we assessed the effect on contractile parameters in three-dimensional (3D) contractile hydrogels (engineered heart tissues, EHTs) and conducted advanced proteomics to understand the consequences of the mutation on Nav1.5 protein-protein interactions. ResultsThe SCN5A-P1891A mutation reduced the sodium current densities and increased both the sodium window current and arrhythmogenicity; however, action potential parameters were unaffected. Advanced proteomics characterised, for the first time, the complete Nav1.5 interactome and revealed that the SCN5A-P1891A mutation negated interactions with fibroblast growth factor 12 (FGF12) and FGF13, that are known to modulate sodium channel activity. Baseline proliferation was unchanged, although aged P1891A-hiPSC-CMs demonstrated enhanced proliferative capacity following mitogenic stimulation. Further, P1891A-hiPSC-CMs exhibited a heightened stress response upon mechanical stretch, resulting in the upregulation of heart failure-associated genes. Strikingly, EHTs derived from P1891A-hiPSC-CMs yielded disparate phenotypes. Whilst the majority condensed only partially and failed to beat synchronously, a small subset condensed fully yet exhibited weak contractile properties, alongside age-associated functional decline. In contrast, EHTs derived from healthy control hiPSC-CMs consistently condensed fully and demonstrated a positive correlation between post-fabrication age and contractile properties ConclusionsOur study presents a unique aetiology of LVHT and reveals a novel association between SCN5A mutations and enhanced human cardiomyocyte proliferation. Further, the inability of P1891A-hiPSC-CMs to consistently form fully condensed 3D cardiac tissues may be linked to their abnormal response to mechanical stretch and provides a powerful 3D model for future mechanistic research and drug development studies to better understand and treat LVHT.

molecular biology↗

bioRxiv2023

α-Melanocyte-Stimulating Hormone Regulates Pathological Cardiac Remodeling by Activating Melanocortin 5 Receptor in Cardiomyocytes

Background-Melanocyte-stimulating hormone (-MSH) regulates diverse physiological functions by activating melanocortin receptors (MC-R). -MSH is predominantly expressed in the pituitary gland, but it is also found in several peripheral tissues such as the skin and heart. However, the role of -MSH and its possible target receptors in the heart remain completely unknown. Therefore, we sought to investigate whether -MSH could be involved in the regulation of pathological cardiac remodeling. MethodsTissue -MSH concentrations and the effects of chronic -MSH administration were investigated in mice subjected to transverse aortic constriction (TAC). Rat H9c2 cells, neonatal mouse ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) were used to study the effects of -MSH and selective MC-R agonists. Inducible cardiomyocyte-specific melanocortin 5 receptor (MC5-R) knockout mouse model was engineered to investigate the role of MC5-R in cardiac hypertrophy. Results-MSH was highly expressed in the mouse heart, particularly in the ventricles, and its level was reduced in the left ventricles of TAC-operated mice. Administration of a stable -MSH analogue protected mice against TAC-induced cardiac hypertrophy and systolic dysfunction. In vitro experiments revealed that cardiomyocytes serve as effector cells for the -MSH mediated antihypertrophic signaling and that selective activation of MC5-R mimics the actions of -MSH. In keeping with these findings, MC5-R was downregulated in the failing mouse heart and stressed hiPSC-CMs. Silencing of MC5-R in mouse cardiomyocytes induced hypertrophy and fibrosis markers in vitro and aggravated TAC-induced cardiac hypertrophy and fibrosis in vivo. Conversely, pharmacological activation of MC5-R improved systolic function and reduced cardiac fibrosis in TAC-operated mice. Conclusions-MSH is expressed in the heart and protects against pathological cardiac remodeling by activating MC5-R in cardiomyocytes. These results suggest that analogues of naturally occurring -MSH, that have been recently approved for clinical use and have agonistic activity at MC5-R, may be of benefit in treating heart failure.

physiology↗

bioRxiv2021

Transcriptomics reveal stretched human pluripotent stem cell-derived cardiomyocytes as an advantageous hypertrophy model

Left ventricular hypertrophy, characterized by hypertrophy of individual cardiomyocytes, is an adaptive response to an increased cardiac workload that eventually leads to heart failure. Previous studies using neonatal rat ventricular myocytes (NRVMs) and animal models have revealed several genes and signaling pathways associated with hypertrophy and mechanical load. However, these models are not directly applicable to humans. Here, we studied the effect of cyclic mechanical stretch on gene expression of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) using RNA sequencing. hiPSC-CMs showed distinct hypertrophic changes in gene expression at the level of individual genes and in biological processes. We also identified several differentially expressed genes that have not been previously associated with cardiomyocyte hypertrophy and thus serve as attractive targets for future studies. When compared to previously published data attained from stretched NRVMs and human embryonic stem cell-derived cardiomyocytes, hiPSC-CMs displayed a smaller number of changes in gene expression, but the differentially expressed genes revealed more pronounced enrichment of hypertrophy-related biological processes and pathways. Overall, these results establish hiPSC-CMs as a valuable in vitro model for studying human cardiomyocyte hypertrophy. Non-standard Abbreviations and AcronymsET-1, endothelin-1; GO, gene ontology; hESC-CM, human embryonic stem cell-derived cardiomyocyte; hiPSC, human induced pluripotent stem cell; hiPSC-CM, human induced pluripotent stem cell-derived cardiomyocyte; MAPK, mitogen-activated protein kinase; MEK1/2, mitogen-activated protein kinase kinase 1/2; NRVM, neonatal rat ventricular myocyte; PKC, protein kinase C; PBS, phosphate-buffered saline; RB+, RPMI 1640 supplemented with B-27; RB-, RPMI 1640 medium supplemented with B-27 without insulin; RT, room temperature; TF, transcription factor

cell biology↗

bioRxiv2018

Molecular atlas of postnatal mouse heart development

RationaleMammals lose the ability to regenerate their hearts within one week after birth. During this regenerative window, cardiac energy metabolism shifts from glycolysis to fatty acid oxidation, and recent evidence suggests that metabolism may participate in controlling cardiomyocyte cell cycle. However, the molecular mechanisms mediating the loss of postnatal cardiac regeneration are not fully understood.\n\nObjectiveThis study aims at providing an integrated resource of mRNA, protein and metabolite changes in the neonatal heart to identify metabolism-related mechanisms associated with the postnatal loss of regenerative capacity.\n\nMethods and ResultsMouse ventricular tissue samples taken on postnatal days 1, 4, 9 and 23 (P01, P04, P09 and P23, respectively) were analyzed with RNA sequencing (RNAseq) and global proteomics and metabolomics. Differential expression was observed for 8547 mRNAs and for 1199 of the 2285 quantified proteins. Furthermore, 151 metabolites with significant changes were identified. Gene ontology analysis, KEGG pathway analysis and fuzzy c-means clustering were used to identify biological processes and metabolic pathways either up- or downregulated on all three levels. Among these were branched chain amino acid degradation (upregulated at P23) and production of free saturated and monounsaturated medium- to long-chain fatty acids (upregulated at P04 and P09; downregulated at P23). Moreover, the HMG-CoA synthase (HMGCS)-mediated mevalonate pathway and ketogenesis were transiently activated. Pharmacological inhibition of HMGCS in primary neonatal rat ventricular cardiomyocytes reduced the percentage of BrdU+ cardiomyocytes, providing evidence that the mevalonate and ketogenesis routes may participate in regulating cardiomyocyte cell cycle.\n\nConclusionsThis is the first systems-level resource combining data from genome-wide transcriptomics with global quantitative proteomics and untargeted metabolomics analyses of the mouse heart throughout the early postnatal period. This integrated multi-level data of molecular changes associated with the loss of cardiac regeneration may open up new possibilities for the development of regenerative therapies.

systems biology↗