Mesenchymal stem cell (MSC)-based therapy using gene delivery systems has been suggested for degenerative diseases. Although MSC-based clinical applications are effective and safe, the mode of action remains unclear. Researchers have commonly applied viral-based gene modification because this system has efficient vehicles. While viral transfection carries many risks, such as oncogenes and chromosomal integration, nonviral gene delivery techniques are less expensive, easier to handle, and safe, although they are less efficient. The electroporation method, which uses Nucleofection technology, provides critical opportunities for hard-to-transfect primary cell lines, including MSCs. Therefore, to improve the therapeutic efficacy using genetically modified MSCs, researchers must determine the optimal conditions for the introduction of the Nucleofection technique in MSCs. Here, we suggest optimal methods for gene modification in PD-MSCs using an electroporation gene delivery system for clinical application.

Retinal degenerative diseases result from oxidative stress and mitochondrial dysfunction, leading to the loss of visual acuity. Damaged retinal pigment epithelial (RPE) and photoreceptor cells undergo mitophagy. Pigment epithelium-derived factor (PEDF) protects from oxidative stress in RPE and improves mitochondrial functions. Overexpression of PEDF in placenta-derived mesenchymal stem cells (PD-MSCs; PD-MSCsPEDF) provides therapeutic effects in retinal degenerative diseases. Here, we investigated whether PD-MSCsPEDF restored the visual cycle through a mitophagic mechanism in RPE cells in hydrogen peroxide (H2O2)-injured rat retinas. Compared with naïve PD-MSCs, PD-MSCsPEDF augmented mitochondrial biogenesis and translation markers as well as mitochondrial respiratory states. In the H2O2-injured rat model, intravitreal administration of PD-MSCsPEDF restored total retinal layer thickness compared to that of naïve PD-MSCs. In particular, PTEN-induced kinase 1 (PINK1), which is the major mitophagy marker, exhibited increased expression in retinal layers and RPE cells after PD-MSCPEDF transplantation. Similarly, expression of the visual cycle enzyme retinol dehydrogenase 11 (RDH11) showed the same patterns as PINK1 levels, resulting in improved visual activity. Taken together, these findings suggest that PD-MSCsPEDF facilitate mitophagy and restore the loss of visual cycles in H2O2-injured rat retinas and RPE cells. These data indicate a new strategy for next-generation MSC-based treatment of retinal degenerative diseases.

Background Cholesterol accumulation and calcium depletion induce hepatic injury via the endoplasmic reticulum (ER) stress response. ER stress regulates the calcium imbalance between the ER and mitochondria. We previously reported that phosphatase of regenerating liver-1 (PRL-1)-overexpressing placenta-derived mesenchymal stem cells (PD-MSCsPRL−1) promoted liver regeneration via mitochondrial dynamics in a cirrhotic rat model. However, the role of PRL-1 in ER stress-dependent calcium is not clear. Therefore, we demonstrated that PD-MSCsPRL−1 improved hepatic functions by regulating ER stress and calcium channels in a rat model of bile duct ligation (BDL). Methods Liver cirrhosis was induced in Sprague–Dawley (SD) rats using surgically induced BDL for 10 days. PD-MSCs and PD-MSCsPRL−1 (2 × 106 cells) were intravenously administered to animals, and their therapeutic effects were analyzed. WB-F344 cells exposed to thapsigargin (TG) were cocultured with PD-MSCs or PD-MSCsPRL−1. Results ER stress markers, e.g., eukaryotic translation initiation factor 2α (eIF2α), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP), were increased in the nontransplantation group (NTx) compared to the control group. PD-MSCsPRL−1 significantly decreased ER stress markers compared to NTx and induced dynamic changes in calcium channel markers, e.g., sarco/endoplasmic reticulum Ca2+ -ATPase 2b (SERCA2b), inositol 1,4,5-trisphosphate receptor (IP3R), mitochondrial calcium uniporter (MCU), and voltage-dependent anion channel 1 (VDAC1) (*p < 0.05). Cocultivation of TG-treated WB-F344 cells with PD-MSCsPRL−1 decreased cytosolic calmodulin (CaM) expression and cytosolic and mitochondrial Ca2+ concentrations. However, the ER Ca2+ concentration was increased compared to PD-MSCs (*p  < 0.05). PRL-1 activated phosphatidylinositol-3-kinase (PI3K) signaling via epidermal growth factor receptor (EGFR), which resulted in calcium increase via CaM expression. Conclusions These findings suggest that PD-MSCsPRL−1 improved hepatic functions via calcium changes and attenuated ER stress in a BDL-injured rat model. Therefore, these results provide useful data for the development of next-generation MSC-based stem cell therapy for regenerative medicine in chronic liver disease.

Background: Accumulation of cholesterol and depletion of calcium induce hepatic injury through the endoplasmic reticulum (ER) stress response. ER stress regulates the calcium imbalance between the ER and mitochondria. Previously, we reported that phosphatase of regenerating liver-1 (PRL-1)-overexpressing placenta-derived mesenchymal stem cells (PD-MSCsPRL-1) promoted liver regeneration through mitochondrial dynamics in a cirrhotic rat model. However, whether PRL-1 is involved in ER stress-dependent calcium is unclear. So, we demonstrated that PD-MSCsPRL-1 improves hepatic functions by regulating ER stress and calcium channels in a rat model of bile duct ligation (BDL). Methods: Liver cirrhosis was induced in Sprague-Dawley (SD) rats using surgically induced BDL for 10 days. PD-MSCs and PD-MSCsPRL-1 (2x106 cells) were intravenously administered to animals, and their therapeutic effects were analyzed. WB-F344 cells exposed to thapsigargin (TG) were cocultured with PD-MSCs or PD-MSCsPRL-1. Results: ER stress markers (e.g., eIF2α, ATF4, and CHOP) were increased in the non-transplantation group (NTx) compared with the control group. PD-MSCsPRL-1 significantly decreased ER stress markers compared to NTx and induced dynamic changes in calcium channel markers (e.g., SERCA2b, IP3R, MCU, and VDAC1) (*p<0.05). In TG-treated WB-F344 cells, cocultivation with PD-MSCsPRL-1 decreased cytosolic CaM expression and cytosolic and mitochondrial Ca2+ concentrations; however, the ER Ca2+ concentration was increased compared to that in PD-MSCs (*p<0.05). Additionally, PRL-1 through epidermal growth factor receptor (EGFR) activated phosphatidylinositol-3-kinase (PI3K) signaling, resulting in calcium increases via CaM expression. Conclusions: These findings suggest that PD-MSCsPRL-1 improved hepatic functions through calcium changes and attenuated ER stress in a BDL-injured rat model. Therefore, these results provide useful data for the development of next-generation MSC-based stem cell therapy for regenerative medicine in chronic liver disease.