Soo Kim’s research while affiliated with Asan Medical Center and other places

Compared with conventional mesenchymal stem cells (MSCs), induced mesenchymal stem cells (iMSCs) from induced pluripotent stem cells are unique cell sources for tissue regeneration. The effect of extracellular vesicles (EVs) secreted from iMSCs on inhibiting acute kidney injury (AKI) to chronic kidney disease (CKD) transition was not reported. In this study, we investigated whether EVs from iMSCs (iMSC-EVs) could inhibit AKI-to-CKD transition. iMSC-EVs exhibited the general characteristics of EVs, such as protein marker expression, morphology, and size. Additionally, iMSC-EVs were detected in renal tissues after intravenous injection. In human renal tubular epithelial cells, the increase in pro-fibrotic gene expression in response to transforming growth factor β1 treatment was decreased by iMSC-EVs. In a mouse model of the AKI-to-CKD transtion induced by folic acid, repeated administration of iMSC-EVs restored renal function at day 14. Specifically, iMSC-EVs reduced interstitial fibrosis, sustained inflammation, various types of cell death, and the number of immune cells infiltrating kidneys. Capillary rarefaction in renal tissue was also reversed by iMSC-EVs. Our results demonstrate that iMSC-EVs reduced interstitial fibrosis, inflammation, and cell death occurring during the CKD transition after AKI. Thus, iMSC-EVs have the potential to block AKI-to-CKD transition.

Background Androgenetic alopecia (AGA) is a common form of hair loss. Androgens, such as testosterone and dihydrotestosterone, are the main causes of AGA. Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) can reduce AGA. However, preparing therapeutic doses of MSCs for clinical use is challenging. Induced pluripotent stem cell-derived MSCs (iMSCs) are homogenous and easily expandable, enabling scalable production of EVs. Hyaluronic acid (HA) can exert various functions including free radical scavenging, immune regulation, and cell migration. Herein, we examined whether hyaluronic acid (HA) stimulation of iMSCs could produce EVs with enhanced therapeutic outcomes for AGA. Methods EVs were collected from iMSCs primed with HA (HA–iMSC–EVs) or without HA (iMSC–EVs). The characteristics of EVs were examined using dynamic light scattering, cryo-transmission electron microscopy, immunoblotting, flow cytometry, and proteomic analysis. In vitro, we compared the potential of EVs in stimulating the survival of hair follicle dermal papilla cells undergoing testosterone-mediated AGA. Additionally, the expression of androgen receptor (AR) and relevant growth factors as well as key proteins of Wnt/β-catenin signaling pathway (β-catenin and phosphorylated GSK3β) was analyzed. Subsequently, AGA was induced in male C57/BL6 mice by testosterone administration, followed by repeated injections of iMSC–EVs, HA–iMSC–EVs, finasteride, or vehicle. Several parameters including hair growth, anagen phase ratio, reactivation of Wnt/β-catenin pathway, and AR expression was examined using qPCR, immunoblotting, and immunofluorescence analysis. Results Both types of EVs showed typical characteristics for EVs, such as size distribution, markers, and surface protein expression. In hair follicle dermal papilla cells, the mRNA levels of AR, TGF-β, and IL-6 increased by testosterone was blocked by HA–iMSC–EVs, which also contributed to the augmented expression of trophic genes related to hair regrowth. However, no notable changes were observed in the iMSC–EVs. Re-activation of Wnt/β-catenin was observed in HA–iMSC–EVs but not in iMSC–EVs, as shown by β-catenin stabilization and an increase in phosphorylated GSK3β. Restoration of hair growth was more significant in HA–iMSC–EVs than in iMSC–EVs, and was comparable to that in mice treated with finasteride. Consistently, the decreased anagen ratio induced by testosterone was reversed by HA–iMSC–EVs, but not by iMSC–EVs. An increased expression of hair follicular β-catenin protein, as well as the reduction of AR was observed in the skin tissue of AGA mice receiving HA–iMSC–EVs, but not in those treated with iMSC–EVs. Conclusions Our results suggest that HA–iMSC–EVs have potential to improve AGA by regulating growth factors/cytokines and stimulating AR-related Wnt/β-catenin signaling.

Background Skin injuries occur for various reasons during whole life. Some chronic wounds could cause an impaired wound healing process characterized by wound hypoxia, high levels of oxygen radicals, elevated levels of matrix metalloproteases, delayed cellular infiltration and granulation tissue formation, reduced angiogenesis, decreased collagen synthesis and organization. In this study, we report the EVs from hyaluronic acid-primed iMSCs (HA-iMSC-EVs) accelerating wound healing and regenerating damaged tissues by inducing the various growth factors in the thermal injury of mice. Methods EVs were collected from iMSCs primed with HA (HA-iMSC-EVs) or without HA (iMSC-EVs) and were isolated using TFF systems. Both EVs analyzed the characteristics. We investigated the proteome of HA-iMSC-EVs using the protein set ontology analysis and protein-protein interaction network. To evaluate the effect of HA-iMSC-EVs on the oxidative stress-induced wound healing delayed model, we assessed the effect of EVs on cell viability, cell migration rate, and the mRNA expression of growth factors using a hydrogen peroxide-exposed HDF model. In addition, we observed elastin and collagen expressions using an ICC staining in the HDF model. In thermal burn wound mice (BALB/c), we compared the effect of EVs in wound closure rate and histological analysis, including expression of elastin, collagen, α-SMA, and CD31. Results HA-iMSC-EVs exhibited typical EV characteristics, including size distribution, markers, and surface protein expression. In GO term analysis, HA-iMSC-EVs increased the proteins associated with ECM, including collagen biosynthesis and elastin fiber formation. In hydrogen peroxide exposed HDF models, HA-iMSC-EVs notably increased cell viability and migration activity. Furthermore, HA-iMSC-EVs increased RNA expression of VEGF, IGF1, and HGF and decreased IL-6 mRNA expression compared to the PBS group. Elastin and collagen expression in the HA-iMSC-EVs group were also significantly increased. In burn-injured mice, HA-iMSC-EVs accelerated wound closure and enhanced histological recovery. HA-iMSC-EVs increased collagen and elastin density on the upper dermis and decreased α-SMA expression. Additionally, HA-iMSC-EVs promoted the capillary density in the dermis. Conclusions Our results suggest that HA-iMSC-EVs accelerated the recovery from burn wound by providing ECM composition signal and regulating growth factors. Our strategy may contribute to the development of alternative treatment option for burn wounds. Trial registration : Not applicable.

Background Myocardial infarction (MI), a representative form of ischemic heart disease, remains a huge burden worldwide. This study aimed to explore whether extracellular vesicles (EVs) secreted from hyaluronic acid (HA)-primed induced mesenchymal stem cells (HA-iMSC-EVs) could enhance the cardiac repair after MI. Results HA-iMSC-EVs showed typical characteristics for EVs such as morphology, size, and marker proteins expression. Compared with iMSC-EVs, HA-iMSC-EVs showed enhanced tube formation and survival against oxidative stress in endothelial cells, while reduced reactive oxygen species (ROS) generation in cardiomyocytes. In THP-1 macrophages, both types of EVs markedly reduced the expression of pro-inflammatory signaling players, whereas HA-iMSC-EVs were more potent in augmenting anti-inflammatory markers. A significant decrease of inflammasome proteins was observed in HA-iMSC-EV-treated THP-1. Further, phospho-SMAD2 as well as fibrosis markers in TGF-β1-stimulated cardiomyocytes were reduced in HA-iMSC-EVs treatment. Proteomic data showed that HA-iMSC-EVs were enriched with multiple pathways including immunity, extracellular matrix organization, angiogenesis, and cell cycle. The localization of HA-iMSC-EVs in myocardium was confirmed after delivery by either intravenous or intramyocardial route, with the latter increased intensity. Echocardiography revealed that intramyocardial HA-iMSC-EVs injections improved cardiac function and reduced adverse cardiac remodeling and necrotic size in MI heart. Histologically, MI hearts receiving HA-iMSC-EVs had increased capillary density and viable myocardium, while showed reduced fibrosis. Conclusions Our results suggest that HA-iMSC-EVs improve cardiac function by augmenting vessel growth, while reducing ROS generation, inflammation, and fibrosis in MI heart. Graphical Abstract

Background Acute kidney injury (AKI) has a complex pathophysiology and imposes serious health concerns worldwide. Extracellular vesicles (EVs) derived from induced mesenchymal stem cells (iMSCs) have been recognized as novel cell-free therapeutics for various inflammatory and degenerative disorders. In this study, we investigated whether iMSCs stimulated with a pan-peroxisome proliferator-activated receptor (PPAR) agonist could enhance the therapeutic efficacy of EVs against AKI. Methods Human iMSCs were primed with or without lanifibranor, a PPAR agonist for 24 h, and EVs were collected after an additional 24 h. The basic characteristics of EVs were evaluated using cryo-transmission electron microscopy imaging, immunoblot detection of EV markers, nanoparticle tracking analysis, and localization in AKI kidneys. In vitro, the potential of the EVs to promote the growth and survival of HK-2 cells undergoing cisplatin-induced apoptosis and anti-inflammatory effects in M1-polarized THP-1 was compared. Subsequently, AKI was induced in BALB/c mice using cisplatin. After 8 and 24 h of cisplatin treatment, iMSC-EVs or pan-PPAR-iMSC-EVs were injected intravascularly. At 96 h after cisplatin administration, the renoprotective effects of iMSC-EVs or pan-PPAR-iMSC-EVs in inhibiting inflammation and apoptosis were compared using serum biochemistry, histology, immunohistochemistry, and gene expression analysis by qPCR. Results Both EV types expressed EV markers and had typical EV morphology, and their localization in the renal tissue was confirmed. The proliferation and survival of HK-2 cells were higher in pan-PPAR-iMSC-EVs than those in iMSC-EVs. In M1-polarized THP-1 cells, the reduction in the mRNA expression of inflammatory cytokines was more significant in pan-PPAR-iMSC-EVs than that in iMSC-EVs. In the mouse model of cisplatin-induced AKI, pan-PPAR-iMSC-EVs markedly enhanced renoprotective effects compared to iMSC-EVs. Specifically, pan-PPAR-iMSC-EVs reduced tissue inflammation, immune cell infiltration, and apoptosis. Pan-PPAR-iMSC-EVs also increased renal capillary density. Conclusion Priming iMSCs with a PPAR agonist significantly improved the therapeutic potential of EVs by reducing inflammation and apoptosis. The reported strategy may contribute to the development of a novel cell-free option for AKI treatment. Trial registration: Not applicable.

Background Myocardial infarction (MI), a representative form of ischemic heart disease, remains a huge burden worldwide. This study aimed to explore whether extracellular vesicles (EVs) secreted from hyaluronic acid (HA)-primed induced mesenchymal stem cells (HA-iMSC-EVs) could enhance the cardiac repair after MI. Results HA-iMSC-EVs showed typical characteristics for EVs such as morphology, size, and marker proteins expression. Compared with iMSC-EVs, HA-iMSC-EVs showed enhanced tube formation and survival against oxidative stress in endothelial cells, while reduced reactive oxygen species (ROS) generation in cardiomyocytes. In THP-1 macrophages, both types of EVs markedly reduced the expression of pro-inflammatory signaling players, whereas HA-iMSC-EVs were more potent in augmenting anti-inflammatory markers. A significant decrease of inflammasome proteins was observed in HA-iMSC-EV-treated THP-1. Further, phospho-SMAD2 as well as fibrosis markers in TGF-b1-stimulated cardiomyocytes were reduced in HA-iMSC-EVs treatment. Proteomic data showed that HA-iMSC-EVs were enriched with multiple pathways including immunity, extracellular matrix organization, angiogenesis, and cell cycle. The localization of HA-iMSC-EVs in myocardium was confirmed after delivery by either intravenous or intramyocardial route, with the latter increased intensity. Echocardiography revealed that intramyocardial HA-iMSC-EVs injections improved cardiac function and reduced adverse cardiac remodeling and necrotic size in MI heart. Histologically, MI hearts receiving HA-iMSC-EVs had increased capillary density and viable myocardium, while showed reduced fibrosis. Conclusions Our results suggest that HA-iMSC-EVs improve cardiac function by augmenting vessel growth, while reducing ROS generation, inflammation, and fibrosis in MI heart.