Cardiovascular diseases (CVDs) are often linked to ageing and are the major cause of death worldwide. The declined proliferation of adult stem cells in the heart often impedes its regenerative potential. Thus, an investigation of the proliferative potential of adult human cardiac stem cells (hCSCs) might be of great interest for improving cell-based treatments of cardiovascular diseases. The application of human blood serum was already shown to enhance hCSC proliferation and reduce senescence. Here, the underlying signalling pathways of serum-mediated hCSC proliferation were studied. We are the first to demonstrate the involvement of the transcription factor NF-κB in the serum-mediated proliferative response of hCSCs by utilizing the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC). RNA-Sequencing (RNA-Seq) revealed ATF6B, COX5B, and TNFRSF14 as potential targets of NF-κB that are involved in serum-induced hCSC proliferation.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by progressive memory impairment and cognitive decline. The APOE4 allele represents one of the most prominent genetic risk factors. In this study, we investigated the impact of APOE4 on the cholinergic neuronal development and on the neuronal inflammatory response to TNF-α stimulation. To address this, human induced pluripotent stem cells (hiPSCs) carrying a homozygous APOE4 genotype and an isogenic APOE3 control were differentiated into cholinergic-like induced neurons (iNs) by LHX8 overexpression. APOE4 was associated with accelerated early neuronal differentiation, as reflected by earlier downregulation of the progenitor marker Nestin. However, delayed expression of synaptophysin indicated impaired synaptic maturation. Functionally, APOE3 iNs exhibited a robust but temporally regulated response to TNF-α, whereas APOE4 iNs were characterized by a delayed yet sustained induction of inflammatory signaling. Moreover, APOE4 iNs displayed an enhanced stress-associated transcriptional response at early differentiation stages. Collectively, these findings suggest that APOE4 influences both neuronal development and the timing and persistence of inflammatory responses, potentially predisposing cholinergic neurons to later dysfunction in AD.

The adult mammalian heart exhibits limited regenerative capacity. Although the epicardium contributes to cardiac injury responses and remodeling, expandable adult human in vitro models for investigating epicardial activation and epithelial-to-mesenchymal (EMT)-associated cellular responses remain limited. Here, we isolated human epicardium-derived cells from the adult heart auricle, expressing WT1⁺/MSLN⁺/CRIP1⁺ and generated an expandable immortalized epicardium-derived cell (iEPDC) population, allowing the investigation of intercellular dynamics upon EMT activation. TGFβ signaling was modulated using SB431542 or TGFβ3. Morphological, immunocytochemical, transcriptomic and functional analyses were performed to investigate treatment-dependent responses. SB431542-treated iEPDCs displayed epithelial-like characteristics and elevated WT1, MSLN and CRIP1 expression, with CRIP1 detected at both transcript and protein levels. TGFβ3-treated cells expressed the mesenchymal markers VIM and CD105 and exhibited spindle-shaped morphology, increased migratory behavior and upregulation of mesenchymal- and remodeling-associated markers. Transcriptomic analyses revealed distinct treatment-dependent profiles, enrichment of ‘focal adhesion’, ‘ECM-receptor interaction’ and cytoskeleton-associated pathways in TGFβ3-treated iEPDCs and intermediate transcriptional characteristics in untreated cells. Together, these findings establish adult iEPDCs as an expandable in vitro model for investigating TGFβ-dependent epicardial activation and EMT-associated processes in the adult human heart. Furthermore, the integration of phenotypic, transcriptomic and functional findings revealed the treatment-responsive plasticity of adult human iEPDCs, supporting future studies of injury-associated epicardial activation.