Human induced pluripotent stem cells (hiPSCs) are reprogrammed cells that have hallmarks similar to embryonic stem cells including the capacity of self-renewal and differentiation into cardiac myocytes. The improvements in reprogramming and differentiating methods achieved in the past 10 years widened the use of hiPSCs, especially in cardiac research. hiPSC-derived cardiac myocytes (CMs) recapitulate phenotypic differences caused by genetic variations, making them human attractive disease models and useful tools for drug discovery and toxicology testing. In addition, hiPSCs can be used as source cells for cardiac regeneration in animal models. Here, we review the advances in the genetic and epigenetic control of cardiomyogenesis that underlies the significant improvement of the induced reprogramming of somatic cells to CMs. We also cover the phenotypic characteristics of the hiPSCs derived CMs, their ability to rescue injured CMs through paracrine effects, the novel approaches in tissue engineering for hiPSC-derived cardiac tissue generation, and finally, their potential use in biomedical applications.

Mycotoxins are secondary metabolites produced by filamentous fungi associated to a variety of acute and chronic foodborne diseases. Current toxicology studies mainly rely on monolayer cell cultures and animal models, which are undeniably affected by several limitations. To bridge the gap between the current in vitro toxicology approach and the in vivo predictivity of the data, we here investigated the cytotoxic effects induced by the mycotoxins sterigmatocystin (STE), ochratoxin A (OTA) and patulin (PAT) on different 2D and 3D cell cultures. We focused on human tumours (neuroblastoma SH-SY5Y cells, and epithelial breast cancer MDA-MB-213 cells) and healthy cells (bone marrow derived mesenchymal stem cells, BM-MSC, and umbilical vein endothelial cells, HUVECs). Cytotoxicity of STE, OTA, and PAT was determined after 24, 48 and 72 h of exposure by ATP assay in both culture models. 3D spheroids morphology was also analysed using the MATLAB-based open-source software AnaSP. Our results highlighted how each cell line and different culture models showed specific sensitivities, reinforcing the importance of using more complex models for toxicology studies and a multiple cell line approach for an improved and more comprehensive risk assessment.

Diffuse intrinsic pontine glioma (DIPG), affecting children aged 4-7 years, is a rare, aggressive tumor that originates in the pons and then spreads to nearby tissue. DIPG is the leading cause of death for pediatric brain tumors due to its infiltrative nature and inoperability. Radiotherapy has only a palliative effect in stabilizing symptoms. In silico and preclinical studies identified ONC201, as a cytotoxic agent against some human cancer cell lines, including DIPG ones. Single crystal X-ray analysis of the complex of the human mitochondrial caseinolytic serine protease type C (hClpP) and ONC201 (PDB ID: 6DL7) allowed to identify hClpP as its main target. Hyperactivation of hClpP causes damage to mitochondrial oxidative phosphorylation and cell death. In some DIPG patients, receiving ONC201, an acquired resistance was observed. In this context, a wide program was initiated to discover original scaffolds for new hClpP activators to treat ONC201-non-responding patients. Harmaline, a small molecule belonging to the chemical class of β -carboline, was identified through Fingerprints for Ligands and Proteins (FLAP), a structure-based Virtual Screening approach. Molecular dynamics simulations and a deep in vitro investigation showed interesting information on the interaction and activation of hClpP by harmaline.