Clinical potentials of human pluripotent stem cells.

Aging, injuries, and diseases can be considered as the result of malfunctioning or damaged cells. Regenerative medicine aims to restore tissue homeostasis by repairing or replacing cells, tissues, or damaged organs, by linking and combining different disciplines including engineering, technology, biology, and medicine. To pursue these goals, the discipline is taking advantage of pluripotent stem cells (PSCs), a peculiar type of cell possessing the ability to differentiate into every cell type of the body. Human PSCs can be isolated from the blastocysts and maintained in culture indefinitely, giving rise to the so-called embryonic stem cells (ESCs). However, since 2006, it is possible to restore in an adult cell a pluripotent ESC-like condition by forcing the expression of four transcription factors with the rejuvenating reprogramming technology invented by Yamanaka. Then the two types of PSC can be differentiated, using standardized protocols, towards the cell type necessary for the regeneration. Although the use of these derivatives for therapeutic transplantation is still in the preliminary phase of safety and efficacy studies, a lot of efforts are presently taking place to discover the biological mechanisms underlying genetic pathologies, by differentiating induced PSCs derived from patients, and new therapies by challenging PSC-derived cells in drug screening.

Human iPSC-Derived 3D Hepatic Organoids in a Miniaturized Dynamic Culture System.

The process of identifying and approving a new drug is a time-consuming and expensive procedure. One of the biggest issues to overcome is the risk of hepatotoxicity, which is one of the main reasons for drug withdrawal from the market. While animal models are the gold standard in preclinical drug testing, the translation of results into therapeutic intervention is often ambiguous due to interspecies differences in hepatic metabolism. The discovery of human induced pluripotent stem cells (hiPSCs) and their derivatives has opened new possibilities for drug testing. We used mesenchymal stem cells and hepatocytes both derived from hiPSCs, together with endothelial cells, to miniaturize the process of generating hepatic organoids. These organoids were then cultivated in vitro using both static and dynamic cultures. Additionally, we tested spheroids solely composed by induced hepatocytes. By miniaturizing the system, we demonstrated the possibility of maintaining the organoids, but not the spheroids, in culture for up to 1 week. This timeframe may be sufficient to carry out a hypothetical pharmacological test or screening. In conclusion, we propose that the hiPSC-derived liver organoid model could complement or, in the near future, replace the pharmacological and toxicological tests conducted on animals.

Generation of the induced pluripotent stem cell line UNIBSi017-A from an individual with cardiospondylocarpofacial syndrome and the MAP3K7 c.737-7A > G variant.

TAK1 is a serine threonine kinase that mediates signal transduction induced by TGFß and bone morphogenetic proteins, and controls a variety of cell functions by modulating the downstream activation of NF-kkB, JNK, and p38. Heterozygous variants in the coding MAP3K7 gene cause the cardiospondylocarpofacial syndrome, characterized by various abnormalities. Skin fibroblasts derived from a patient carrying the MAP3K7 c.737-7A>G heterozygous variant were reprogrammed using Sendai viral vector system carrying the Yamanaka factors. The generated induced pluripotent stem cells (iPSC) line retained the original genotype, expressed pluripotency markers, and differentiated into cells of the three germ layers.

Generation of induced pluripotent stem cells (iPSC) from an atrial fibrillation patient carrying a KCNA5 p.D322H mutation.

Atrial fibrillation (AF) is the most common sustained arrhythmia associated with several cardiac risk factors, but increasing evidences indicated a genetic component. Indeed, genetic variations of the atrial specific KCNA5 gene have been identified in patients with early-onset lone AF. To investigate the molecular mechanisms underlying AF, we reprogrammed to pluripotency polymorphonucleated leukocytes isolated from the blood of a patient carrying a KCNA5 p.D322H mutation, using a commercially available non-integrating system. The generated iPSCs expressed pluripotency markers and differentiated toward cells belonging to the three embryonic germ layers. Moreover, the cells showed a normal karyotype and retained the p.D322H mutation.

Generation of induced pluripotent stem cells (iPSC) from an atrial fibrillation patient carrying a PITX2 p.M200V mutation.

Atrial fibrillation (AF) is the most common sustained arrhythmia associated with several cardiac risk factors, but increasing evidences indicated a genetic component. Indeed, genetic variations of the specific PITX2 gene have been identified in patients with early-onset AF. To investigate the molecular mechanisms underlying AF, we reprogrammed to pluripotency polymorphonucleated leukocytes isolated from the blood of a patient carrying a PITX2 p.M200V mutation, using a commercially available non-integrating expression system. The generated iPSCs expressed pluripotency markers and differentiated toward cells belonging to the three embryonic germ layers. Moreover, the cells showed a normal karyotype and retained the PITX2 p.M200V mutation.