Biology subjects

Angelini, G.

Publications and source records attributed to Angelini, G..

4 recordsLinked to original sources

bioRxiv2026

Validation of differentiated sinoatrial-like hiPSCs as a model of native sinus node myocytes

BackgroundHuman induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) constitute an attractive system for basic research and pharmacologic screening of new molecules of clinical interest. Numerous protocols aiming at differentiating atrial- or ventricular-like cardiomyocytes (hiPSC-CMs) are available. Conversely, only a few are available for obtaining patient-derived sinoatrial node-like pacemaker myocytes (PM-hiPSC-CMs). Here we validate a new protocol to differentiate mature PM-hiPSC-CMs as a model of native sinoatrial node (SAN) myocytes. MethodsWe generated PM-hiPSC-CMs through a 2D matrix-sandwich method promoting epithelial-to-mesenchymal transition and small molecule-based temporal modulation of Wnt signaling pathway. In addition, we treated our cells with triiodothyronine, dexamethasone and intracellular cyclic AMP (DTA) to enhance expression of proteins involved in intracellular Ca2+ handling. ResultsProteomic analyses showed expression of key SAN proteins in DTA-treated PM-hiPSC-CMs. Importantly, expression of proteins related to Ca2+ handling was increased in DTA-treated PM-hiPSC-CMs compared to untreated ones. DTA-treated PM-hiPSC-CMs displayed action potentials, ionic currents and intracellular Ca2+ dynamics typical of native SAN. In addition, pacemaker activity responded to both {beta}-adrenergic and muscarinic stimulation. ConclusionsOur data indicate that the differentiation protocol effectively generates PM-hiPSC-CMs with typical native human SAN features. This protocol may serve as a potential approach to generate PM-hiPSC-CMs from patients with history of sinoatrial node disfunction (SND) carrying different mutations in ion channels underlying pacemaking. In addition, these in vitro models of SND could be used for testing long-term vector-based gene therapeutic strategies to handle bradycardia.

cell biology↗

bioRxiv2025

A resource and computational approach for quantifying gene editing allelism at single-cell resolution

CRISPR-Cas9-based gene editing is a powerful approach to developing gene and cell therapies for several diseases. Engineering cell therapies requires accurate assessment of gene editing allelism because editing patterns can vary across cells leading to genotypic heterogeneity. This can hinder development of robust cell therapies. Droplet-based targeted single-cell DNA sequencing (scDNAseq) has been used to genotype targeted loci across thousands of cells enabling high-throughput assessment of gene editing efficiency. Here, we constructed a "ground truth" gene editing single-cell DNAseq atlas, along with an artifact-aware computational workflow called GUMM (Genotyping Using Mixture Models) to systematically infer single-cell allelism from these data. This resource was created by expanding CRISPR-Cas9-edited HL-60 clones that harbored distinct insertion-deletion (indel) profiles in CLEC12A and mixing them at pre-defined ratios to create artificial cocktails that mimic the potential editing diversity of a CRISPR-Cas9 experiment. This enabled assessment of technical artifacts that confound interpretation of allelism in the readouts of gene edited cells. GUMM was able to accurately genotype cells and infer the original clonal composition of the artificial cocktails even in the presence of artifacts.

bioinformatics↗

bioRxiv2024

circRNA-miRNA-mRNA networks reveal a proangiogenic action of circNPHP1 in human ischemic heart disease

BackgroundIschemic heart disease (IHD) is characterized by insufficient myocardial blood flow in the left ventricle and aggravated by diabetes mellitus. Endothelial resilience and reparative angiogenesis are tightly controlled processes. Gene expression is regulated by multimodal interactions between RNA species. Circular RNAs (circRNAs) can sponge microRNAs (miRNAs) to reduce the repressive effects of miRNAs on its messenger RNA (mRNAs) targets. MethodsLeft ventricle whole RNA-sequencing (circRNAs, mRNAs) and small RNA- sequencing (miRNAs) datasets were obtained from 3 patient groups: IHD with/out T2DM and controls (N=11 to 12/group) as part of a prospective observational cardiac surgery study. The interactions between differentially expressed (DE) circRNAs, miRNA and mRNAs were identified with a customized bioinformatics pipeline. The emerging networks were screened using endothelial-specific RNA-sequencing datasets from GEO resulting in EC-rich networks. CircRNAs from these networks were subsequently screened (RT-PCR) in endothelial cells (ECs) exposed to disease-mimicking conditions vs control. Afterwards, circRNA pulldown allowed to interrogate the circRNA-miRNAs interactome in ECs. EC biology assays using loss-of-function and gain-of-function approaches corroborated the study. ResultsWe identified novel circRNA-miRNA-mRNA interactions in the human diseased heart. CircNPHP1, which is upregulated in IHD with/out Type-2 diabetes mellitus (T2DM), sponges miR-221-3p to de-repress VEGF-A and BCL2, increasing the angiogenic capacity of ECs under disease and disease-mimicking conditions. ConclusionsThe interactions between individual members of different RNA species are affected by IHD. The therapeutic value of circNPHP1/miR-221-3p axis could be further investigated. Visual Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=61 SRC="FIGDIR/small/597402v2_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@18a3b0forg.highwire.dtl.DTLVardef@2b5dc1org.highwire.dtl.DTLVardef@11848c3org.highwire.dtl.DTLVardef@1511c9e_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIWe found a novel circRNA-miRNA-mRNA network in IHD and Type 2 diabetes. C_LIO_LICircNPHP1 regulates angiogenesis and proliferation in the cardiac ECs exposed to conditions mimicking IHD and Type 2 diabetes. C_LIO_LIWe elucidated a novel pro-angiogenic subnetwork commanded by circNPHP1/miR-221-3p/BCL2/VEGFA. C_LIO_LIWe identified circNPHP1 as a potential new target for therapeutic angiogenesis. C_LI

cell biology↗

bioRxiv2019

Multiplexed and Inducible Gene Modulation in Human Pluripotent Stem Cells by CRISPR Interference and Activation

CRISPR-Cas9-mediated gene interference (CRISPRi) and activation (CRISPRa) approaches hold promise for functional genomic studies and genome-wide screens in human pluripotent stem cells (hPSCs). However, in contrast to CRISPR-Cas9 nuclease approaches, the efficiency of CRISPRi/a depends on continued expression of the dead Cas9 (dCas9) effector and guide RNA (gRNA), which can vary substantially depending on transgene design and delivery. Here, we design new fluorescently labeled piggyBac (PB) vectors to deliver robust and stable expression of multiplexed gRNAs. In addition, we generate hPSC lines harboring AAVS1-integrated, inducible and fluorescent dCas9-KRAB and dCas9-VPR transgenes to allow for accurate quantification and tracking of cells that express both the dCas9 effectors and gRNAs. We then employ these systems to target the TCF4 gene and conduct a rigorous assessment of expression levels of the dCas9 effectors, gRNAs and targeted gene. Collectively, these data provide proof-of-principle application of a stable, multiplexed PB gRNA delivery system that can be widely exploited to further enable genome engineering studies in hPSCs. Paired with diverse CRISPR tools including our dual fluorescence CRISPRi/a cell lines, this system would facilitate functional dissection of individual genes and pathways as well as larger-scale screens for studies of development and disease.

molecular biology↗