Exosomal miR-17-5p from human embryonic stem cells prevents pulmonary fibrosis by targeting thrombospondin-2.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible lung disease characterized by pulmonary fibrosis and lung dysfunction, ultimately leading to respiratory failure. Many preclinical studies have investigated the therapeutic potential of stem cell-derived exosomes in this disease, particularly mesenchymal stem cell-derived exosomes. However, the effects of embryonic stem cell-derived exosomes in IPF remain unclear. METHODS: We established a bleomycin (BLM)-induced pulmonary fibrosis mice model and administered human embryonic stem cell exosomes (hESC-exo) from the first day after BLM treatment. The effects of hESC-exo were assessed by pulmonary function tests, biochemical analysis, histochemistry, quantitative real-time polymerase chain reaction (qPCR), and western blot (WB). RNA-seq was used to screen for the potential therapeutic targets of hESC-exo in fibrotic lungs; the identified signaling axis was characterized using a luciferase assay, qPCR, and WB. RESULTS: Results indicated hESC-exo administration notably alleviated inflammation, removed deposited collagen, and rescued alveolar architecture in the lungs of BLM-induced mice. In vivo and in vitro tests revealed that hESC-exo-derived miR-17-5p directly bound thrombospondin-2 (Thbs2) to regulate inflammation and fibrosis; thus, hESC-exo protected against BLM toxicity in the lungs via the miR-17-5p/Thbs2 axis. CONCLUSION: These results suggest a promising new treatment for fibrosis-associated diseases.

Mesenchymal stem cells alleviate aging in vitro and in vivo.

Background: Aging is a natural and multi-factorial phenomenon associated with multiple human pathologies. Mesenchymal stem cells (MSCs) hold great promise in clinical fields of medicine including tissue repair, cardiovascular disease, and brain ischemic injury. The purpose of this study was to explore the roles of MSCs in improving the condition of aging cells, repairing aging tissues and organs, and extending the life span of elderly mice. Methods: This study was carried out both in vitro and in vivo. We used MSCs to intervene with IMR-90 senescent cells induced by D-galactose and aged C57BL/6 mice. Results: After 48 hours of co-culturing the aged cells with MSCs, the up-regulated expression of inflammatory factor, interleukin 6 (IL6), and the down-regulated expression of several growth factors, such as transforming growth factor (TGFß1) and growth differentiation factor (GDF11), in D-galactose induced senescent cells were reversed. Moreover, compared with aged cells, the number of mitochondria and the telomere length were increased with MSC treatment. Similarly, in aged mice, the symptoms related to aging were improved after MSC treatment: the mouse hair became shiny and dense, and the symptoms of bladder overactivity were relieved. Hematoxylin and eosin (H&E) and Masson's trichrome staining showed that the histopathological changes in skin, bladder, liver, and lung were apparently improved. Conclusions: Treatment with MSCs effectively improves aging-related phenotypes and plays a beneficial role in improving aging and aging-related diseases.

Systemic proteomics and miRNA profile analysis of exosomes derived from human pluripotent stem cells.

BACKGROUND: Increasing studies have reported the therapeutic effect of mesenchymal stem cell (MSC)-derived exosomes by which protein and miRNA are clearly characterized. However, the proteomics and miRNA profiles of exosomes derived from human embryonic stem cells (hESCs) and human-induced pluripotent stem cells (hiPSCs) remain unclear. METHODS: In this study, we isolated exosomes from hESCs, hiPSCs, and human umbilical cord mesenchymal stem cells (hUC-MSCs) via classic ultracentrifugation and a 0.22-µm filter, followed by the conservative identification. Tandem mass tag labeling and label-free relative peptide quantification together defined their proteomics. High-throughput sequencing was performed to determine miRNA profiles. Then, we conducted a bioinformatics analysis to identify the dominant biological processes and pathways modulated by exosome cargos. Finally, the western blot and RT-qPCR were performed to detect the actual loads of proteins and miRNAs in three types of exosomes. RESULTS: Based on our study, the cargos from three types of exosomes contribute to sophisticated biological processes. In comparison, hESC exosomes (hESC-Exos) were superior in regulating development, metabolism, and anti-aging, and hiPSC exosomes (hiPSC-Exos) had similar biological functions as hESC-Exos, whereas hUC-MSCs exosomes (hUC-MSC-Exos) contributed more to immune regulation. CONCLUSIONS: The data presented in our study help define the protein and miRNA landscapes of three exosomes, predict their biological functions via systematic and comprehensive network analysis at the system level, and reveal their respective potential applications in different fields so as to optimize exosome selection in preclinical and clinical trials.

CUGBP1, a crucial factor for heart regeneration in mice.

The mammalian heart is capable of achieving perfect regeneration following cardiac injury through sustained cardiomyocyte proliferation during the early period after birth. However, this regenerative capacity is lost by postnatal day 7 and throughout adulthood. CUGBP1 is critical for normal cardiac development but its role in heart regeneration remains unclear. Cardiac CUGBP1 levels are high in the early postnatal period and soon downregulate to adult levels within 1 week following birth in mice. The simultaneously diminished regenerative capacity and CUGBP1 levels by postnatal day lead us to hypothesize that CUGBP1 may be beneficial in heart regeneration. In this study, the function of CUGBP1 in heart regeneration was tested by a heart apex resection mouse model. We demonstrate that cardiac inactivation of CUGBP1 impairs neonatal heart regeneration at P1, in turn, replenishment of CUGBP1 levels prolong regenerative potential at P8 and P14. Furthermore, our results imply that the Wnt/ß-catenin signaling and GATA4 involve in the CUGBP1 modulated neonatal heart regeneration. Altogether, our findings support CUGBP1 as a key factor promoting post-injury heart regeneration and provide a potential therapeutic method for heart disease.

Coordinated Regulation of Grape Berry Flesh Color by Transcriptional Activators and Repressors.

Yan73 is a teinturier Vitis vinifera variety with red berry flesh, but the molecular mechanisms underlying its flesh coloration remain unclear. We analyzed the flavonoid metabolic and transcriptome profiles of Yan73 berry red and white flesh using HPLC-ESI-MS/MS and RNA-sequencing technologies. Anthocyanins are the main flavonoids responsible for Yan73 berry flesh color, and the coloration is coordinately regulated by the VvMYBA1 transcriptional activator and VvMYBC2-L1 transcriptional repressor. Furthermore, yeast one- and two-hybrid, dual luciferase, and bimolecular fluorescence complementation assays suggested that VvMYBA1 positively regulates Yan73 berry flesh color via interactions with VvWDR1 and the activation of the VvCHI3, VvOMT, and VvGST4 promoters, whereas VvMYBC2-L1 negatively regulates Yan73 berry flesh color, possibly by competing with the R2R3-MYB transcriptional activators for bHLH partners or by repressing VvOMT and VvGST4 expression. Our findings provide new insights into the molecular mechanisms regulating grape flesh color.