Coronary heart disease (CHD) is a leading cause of death globally, while its current management is limited to reducing the myocardial infarction area without actually replacing dead cardiomyocytes. Direct cell reprogramming is a method of cellular cardiomyoplasty which aims for myocardial tissue regeneration, and CD34+ cells are one of the potential sources due to their shared embryonic origin with cardiomyocytes. However, the isolation and culture of non-adherent CD34+ cells is crucial to obtain adequate cells for high-efficiency genetic modification. This study aimed to investigate the optimal method for isolation and culture of CD34+ peripheral blood cells using certain culture media. A peripheral blood sample was obtained from a healthy subject and underwent pre-enrichment, isolation, and expansion. The culture was subsequently observed for their viability, adherence, and confluence. Day 0 observation of the culture showed a healthy CD34+ cell with a round cell shape, without any adherent cells present yet. Day 4 of observation showed that CD34+ cells within the blood plasma medium became adherent, indicated by their transformations into spindle or oval morphologies. Meanwhile, CD34+ cells in vitronectin and fibronectin media showed no adherent cells and many of them died. Day 7 observation revealed more adherent CD34+ cells in blood plasma medium, and which had 75% of confluence. In conclusion, the CD34+ cells that were isolated using a combination of density and magnetic methods may be viable and adequately adhere in culture using blood plasma medium, but not in cultures using fibronectin and vitronectin.

Stem cells are highly resistant to viral infection compared to their differentiated progeny; however, the mechanism is mysterious. Here, we analyzed gene expression in mammalian stem cells and cells at various stages of differentiation. We find that, conserved across species, stem cells express a subset of genes previously classified as interferon (IFN) stimulated genes (ISGs) but that expression is intrinsic, as stem cells are refractory to interferon. This intrinsic ISG expression varies in a cell-type-specific manner, and many ISGs decrease upon differentiation, at which time cells become IFN responsive, allowing induction of a broad spectrum of ISGs by IFN signaling. Importantly, we show that intrinsically expressed ISGs protect stem cells against viral infection. We demonstrate the in vivo importance of intrinsic ISG expression for protecting stem cells and their differentiation potential during viral infection. These findings have intriguing implications for understanding stem cell biology and the evolution of pathogen resistance.