OBJECTIVE: To investigate the regulatory effect and mechanism of DNA methyltransferase 3A (DNMT3a) in hydroquinone-induced hematopoietic stem cell toxicity. METHODS: Cells (HSPC-1) were divided into 4 groups, that is A: normal HSPC-1; B: HQ-intervented HSPC-1; C: group B + pcDNA3 empty vector; D: group B + pcDNA3- DNMT3a. RT-qPCR and Western blot were used to detect the expression levels of DNMT3a and PARP-1 mRNA and protein, respectively. Cell morphology was observe; Cell viability and apoptosis rate of HSPC-1 were detected by MTT and flow cytometry, respectively. RESULTS: Compared with group A, the expression levels of DNMT3a mRNA and protein in HSPC-1 of group B were decreased, while PARP-1 mRNA and protein were increased (P<0.05); there was no significant difference in the above indexes between group C and group B; compared with group B, the expression levels of DNMT3a mRNA and protein showed increased, while PARP-1 mRNA and protein were decreased significantly in cells of group D transfected with DNMT3a (P<0.05). Cells in each group were transfected with DNMT3a and cultured for 24 h, HSPC-1 in group A showed high density growth and mononuclear fusion growth, while the number of HSPC-1 in group B and C decreased and grew slowly. Compared with group B and C, the cell growth rate of group D was accelerated. The MTT analysis showed that cell viability of HSPC-1 in group B were lower than that of group A at 24 h, 48 h and 72 h (P<0.05); after transfected with DNMT3a, the cell viability of HSPC-1 in group D were higher than that of group B at 24 h, 48 h and 72 h (P<0.05). The apoptosis rate of cells in group B was significantly higher than that of group A (P<0.001), while the apoptosis rate in group D was lower than that of group B (P<0.001). CONCLUSION DNMT3a may be involved in the damage of hematopoietic stem cells induced by hydroquinone, which may be related to the regulation of PARP-1 activity by hydroquinone-inhibited DNMT3a.
Apoptosis ; Cell Proliferation ; DNA Methyltransferase 3A ; Hematopoietic Stem Cells/drug effects* ; Humans ; Hydroquinones/toxicity* ; Poly (ADP-Ribose) Polymerase-1 ; RNA, Messenger/metabolism*

OBJECTIVE: To investigate the the effects of leptin on the proliferation, differentiation and PTEN expression of rat retinal progenitor cells (RPCs) cultured under hypoxic condition. METHODS: SD rat RPCs were cultured in normoxic conditions or exposed to hypoxia in the presence of 0, 0.3, 1.0, 3.0, 10, and 30 nmol/L leptin for 12, 48 and 72 h, and the cell viability was assessed using cell counting kit 8 (CCK 8) assay. The RPCs in primary culture were divided into control group, hypoxia group, and hypoxia+leptin group, and after 48 h of culture, the cell medium was replaced with differentiation medium and the cells were further cultured for 6 days. Immunofluorescence staining was employed to detect the cells positive for β-tubulin III and GFAP, and Western blotting was used to examine the expression of PTEN at 48 h of cell culture. RESULTS: The first generation of RPCs showed suspended growth in the medium with abundant and bright cellular plasma and formed mulberry like cell spheres after 2 days of culture. Treatment with low-dose leptin (below 3.0 nmol/L) for 48 h obviously improved the viability of RPCs cultured in hypoxia, while at high concentrations (above 10 nmol/L), leptin significantly suppressed the cell viability (P < 0.05). The cells treated with 3.0 nmol/L leptin for 48 h showed the highest viability (P < 0.05). After treatment with 3.0 nmol/L leptin for 48 h, the cells with hypoxic exposure showed similar GFAP and β-tubulin Ⅲ positivity with the control cells (P>0.05), but exhibited an obvious down-regulation of PTEN protein expression compared with the control cells (P < 0.05). CONCLUSION In rat RPCs with hypoxic exposure, treatment with low dose leptin can promote the cell proliferation and suppress cellular PTEN protein expression without causing significant effects on cell differentiation.
Animals ; Cell Differentiation/drug effects* ; Cell Hypoxia/drug effects* ; Cell Proliferation/drug effects* ; Cells, Cultured ; Leptin/pharmacology* ; PTEN Phosphohydrolase/metabolism* ; Rats ; Rats, Sprague-Dawley ; Retina/metabolism* ; Stem Cells/metabolism* ; Tubulin

The coronavirus disease 2019 (COVID-19) pandemic is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is spread primary via respiratory droplets and infects the lungs. Currently widely used cell lines and animals are unable to accurately mimic human physiological conditions because of the abnormal status of cell lines (transformed or cancer cells) and species differences between animals and humans. Organoids are stem cell-derived self-organized three-dimensional culture in vitro and model the physiological conditions of natural organs. Here we showed that SARS-CoV-2 infected and extensively replicated in human embryonic stem cells (hESCs)-derived lung organoids, including airway and alveolar organoids which covered the complete infection and spread route for SARS-CoV-2 within lungs. The infected cells were ciliated, club, and alveolar type 2 (AT2) cells, which were sequentially located from the proximal to the distal airway and terminal alveoli, respectively. Additionally, RNA-seq revealed early cell response to virus infection including an unexpected downregulation of the metabolic processes, especially lipid metabolism, in addition to the well-known upregulation of immune response. Further, Remdesivir and a human neutralizing antibody potently inhibited SARS-CoV-2 replication in lung organoids. Therefore, human lung organoids can serve as a pathophysiological model to investigate the underlying mechanism of SARS-CoV-2 infection and to discover and test therapeutic drugs for COVID-19.
Adenosine Monophosphate/therapeutic use* ; Alanine/therapeutic use* ; Alveolar Epithelial Cells/virology* ; Antibodies, Neutralizing/therapeutic use* ; COVID-19/virology* ; Down-Regulation ; Drug Discovery ; Human Embryonic Stem Cells/metabolism* ; Humans ; Immunity ; Lipid Metabolism ; Lung/virology* ; RNA, Viral/metabolism* ; SARS-CoV-2/physiology* ; Virus Replication/drug effects*

Once pulp necrosis or apical periodontitis occurs on immature teeth, the weak root and open root apex are challenging to clinicians. Berberine (BBR) is a potential medicine for bone disorders, therefore, we proposed to apply BBR in root canals to enhance root repair in immature teeth. An in vivo model of immature teeth with apical periodontitis was established in rats, and root canals were filled with BBR, calcium hydroxide or sterilized saline for 3 weeks. The shape of the roots was analyzed by micro-computed tomography and histological staining. In vitro, BBR was introduced into stem cells from apical papilla (SCAPs). Osteogenic differentiation of stem cells from apical papilla was investigated by alkaline phosphatase activity, mineralization ability, and gene expression of osteogenic makers. The signaling pathway, which regulated the osteogenesis of SCAPs was evaluated by quantitative real time PCR, Western blot analysis, and immunofluorescence. In rats treated with BBR, more tissue was formed, with longer roots, thicker root walls, and smaller apex diameters. In addition, we found that BBR promoted SCAPs osteogenesis in a time-dependent and concentration-dependent manner. BBR induced the expression of β-catenin and enhanced β-catenin entering into the nucleus, to up-regulate more runt-related nuclear factor 2 downstream. BBR enhanced root repair in immature teeth with apical periodontitis by activating the canonical Wnt/β-catenin pathway in SCAPs.
Animals ; Berberine ; pharmacology ; Cell Differentiation ; drug effects ; Dental Papilla ; Male ; Osteogenesis ; drug effects ; Periapical Periodontitis ; therapy ; Rats ; Stem Cells ; cytology ; drug effects ; metabolism ; Wnt Signaling Pathway ; drug effects ; Wnt3A Protein ; genetics ; metabolism ; X-Ray Microtomography

An ideal animal model of azoospermia would be a powerful tool for the evaluation of spermatogonial stem cell (SSC) transplantation. Busulfan has been commonly used to develop such a model, but 30%-87% of mice die when administered an intraperitoneal injection of 40 mg kg^-1. In the present study, hematoxylin and eosin staining, Western blot, immunofluorescence, and quantitative real-time polymerase chain reaction were used to test the effects of busulfan exposure in a mouse model that received two intraperitoneal injections of busulfan at a 3-h interval at different doses (20, 30, and 40 mg kg^-1) on day 36 or a dose of 40 mg kg^-1 at different time points (0, 9, 18, 27, 36, and 63 days). The survival rate of the mice was 100%. When the mice were treated with 40 mg kg^-1 busulfan, dramatic SSC depletion occurred 18 days later and all of the germ cells were cleared by day 36. In addition, the gene expressions of glial cell line-derived neurotrophic factor (GDNF), fibroblast growth factor 2 (FGF2), chemokine (C-X-C Motif) ligand 12 (CXCL12), and colony-stimulating factor 1 (CSF1) were moderately increased by day 36. A 63-day, long-term observation showed the rare restoration of endogenous germ cells in the testes, suggesting that the potential period for SSC transplantation was between day 36 and day 63. Our results demonstrate that the administration of two intraperitoneal injections of busulfan (40 mg kg^-1 in total) at a 3-h interval to mice provided a nonlethal and efficient method for recipient preparation in SSC transplantation and could improve treatments for infertility and the understanding of chemotherapy-induced gonadotoxicity.
Adult Germline Stem Cells/transplantation* ; Animals ; Azoospermia/chemically induced* ; Busulfan/toxicity* ; Disease Models, Animal ; Infertility, Male/chemically induced* ; Injections, Intraperitoneal ; Male ; Mice ; Spermatogenesis/drug effects* ; Spermatogonia/drug effects* ; Stem Cell Transplantation/methods*

OBJECTIVE: To explore the protective effect of NANOG against hydrogen peroxide (H2O2) -induced cell damage in the human hair follicle mesenchymal stem cells (hHF-MSCs). METHODS: NANOG was expressed from a lentiviral vector, pLVX-IRES-ZsGreen. NANOG hHF-MSCs and vector hHF-MSCs were treated with 400 μmol/L hydrogen peroxide (H2O2) for 2 h, the cell survival rate, cell morphology, ROS production, apoptosis and expression of AKT, ERK, and p21 were determined and compared. RESULTS: Our results showed that NANOG could activate AKT and upregulate the expression of p-AKT, but not p-ERK. When treated with 400 μmol/L H2O2, NANOG hHF-MSCs showed higher cell survival rate, lower ROS production and apoptosis, higher expression of p-AKT, higher ratio of p-AKT/AKT. CONCLUSION Our results suggest that NANOG could protect hHF-MSCs against cell damage caused by H2O2 through activating AKT signaling pathway.
Cell Survival ; Drug Evaluation, Preclinical ; Hair Follicle ; cytology ; Humans ; Hydrogen Peroxide ; Lentivirus ; Mesenchymal Stem Cells ; drug effects ; metabolism ; Nanog Homeobox Protein ; metabolism ; pharmacology ; Oxidative Stress ; drug effects ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction

As the epitome of the modern regenerative medicine, stem cells were proposed in the basic sense no more than 200 years ago. However, the concept of "stem cells" existed long before the modern medical description. The hypothesis that all things, including our sentient body, were generated from a small origin was shared between Western and Chinese people. The ancient Chinese philosophers considered Jing (also known as essence) as the origin of life. In Chinese medicine (CM), Jing is mainly stored in Kidney (Shen) and the so-called Shen-Jing (Kidney essence). Here, we propose that Shen-Jing is the CM term used to express the meaning of "origin and regeneration". This theoretical discovery has at least two applications. First, the actions underlying causing Shen-Jing deficiency, such as excess sexual intercourse, chronic diseases, and aging, might damage the function of stem cells. Second, a large number of Chinese herbs with Shen-Jing-nourishing efficacy had been proven to affect stem cell proliferation and differentiation. Therefore, if Shen-Jing in CM is equivalent with stem cells in regenerative medicine, higher effective modulators for regulating stem-cell behaviors from Kidney-tonifying herbs would be expected.
Drugs, Chinese Herbal ; pharmacology ; Humans ; Kidney ; drug effects ; Medicine, Chinese Traditional ; Regenerative Medicine ; Stem Cells

Diffuse intrinsic pontine glioma (DIPG) is the main cause of brain tumor-related death among children. Until now, there is still a lack of effective therapy with prolonged overall survival for this disease. A typical strategy for preclinical cancer research is to find out the molecular differences between tumor tissue and para-tumor normal tissue, in order to identify potential therapeutic targets. Unfortunately, it is impossible to obtain normal tissue for DIPG because of the vital functions of the pons. Here we report the human fetal hindbrain-derived neural progenitor cells (pontine progenitor cells, PPCs) as normal control cells for DIPG. The PPCs not only harbored similar cell biological and molecular signatures as DIPG glioma stem cells, but also had the potential to be immortalized by the DIPG-specific mutation H3K27M in vitro. These findings provide researchers with a candidate normal control and a potential medicine carrier for preclinical research on DIPG.
Animals ; Brain Stem Neoplasms ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Cellular Senescence ; Female ; Glioma ; genetics ; metabolism ; pathology ; Histones ; genetics ; Humans ; Mice, Inbred NOD ; Mice, SCID ; Neoplasm Transplantation ; Neoplastic Stem Cells ; drug effects ; metabolism ; pathology ; Neural Stem Cells ; drug effects ; metabolism ; pathology ; Pons ; embryology ; metabolism ; pathology ; Primary Cell Culture

OBJECTIVE: To investigate the effects of autophagy on osteogenic differentiation of stem cells from the apical papilla (SCAPs) in the presence of tumor necrosis factor- (TNF-) stimulation . METHODS: SCAPs treated with TNF- (0, 5, and 10 ng/mL) with or without 5 mmol/L 3-MA were examined for the expression of autophagy marker LC3-Ⅱ using Western blotting. The cells were transfected with GFP-LC3 plasmid and fluorescence microscopy was used for quantitative analysis of intracellular GFP-LC3; AO staining was used to detect the acidic vesicles in the cells. The cell viability was assessed with CCK-8 assays and the cell apoptosis rate was analyzed using flow cytometry. The cells treated with TNF- or with TNF- and 3-MA were cultured in osteogenic differentiation medium for 3 to 14 days, and real- time PCR was used to detect the mRNA expressions of osteogenesis-related genes (ALP, BSP, and OCN) for evaluating the cell differentiation. RESULTS: TNF- induced activation of autophagy in cultured SCAPs. Pharmacological inhibition of TNF--induced autophagy by 3-MA significantly decreased the cell viability and increased the apoptosis rate of SCAPs ( < 0.05). Compared with the cells treated with TNF- alone, the cells treated with both TNF- and 3-MA exhibited decreased expressions of the ALP and BSP mRNA on days 3, 7 and 14 during osteogenic induction ( < 0.05) and decreased expression of OCN mRNA on days 3 and 7 during the induction ( < 0.05). CONCLUSIONS Autophagy may play an important role during the osteogenic differentiation of SCAPs in the presence of TNF- stimulation.
Autophagy ; drug effects ; physiology ; Cell Differentiation ; drug effects ; physiology ; Cell Survival ; drug effects ; Cells, Cultured ; Dental Papilla ; cytology ; Green Fluorescent Proteins ; Humans ; Osteogenesis ; physiology ; Stem Cells ; drug effects ; physiology ; Transfection ; Tumor Necrosis Factor-alpha ; administration & dosage ; antagonists & inhibitors ; pharmacology

Genetic studies have revealed a critical role of Distal-homeobox (Dlx) genes in bone formation, and our previous study showed that Dlx2 overexpressing in neural crest cells leads to profound abnormalities of the craniofacial tissues. The aim of this study was to investigate the role and the underlying molecular mechanisms of Dlx2 in osteogenic differentiation of mouse bone marrow stromal cells (BMSCs) and pre-osteoblast MC3T3-E1 cells. Initially, we observed upregulation of Dlx2 during the early osteogenesis in BMSCs and MC3T3-E1 cells. Moreover, Dlx2 overexpression enhanced alkaline phosphatase (ALP) activity and extracellular matrix mineralization in BMSCs and MC3T3-E1 cell line. In addition, micro-CT of implanted tissues in nude mice confirmed that Dlx2 overexpression in BMSCs promoted bone formation in vivo. Unexpectedly, Dlx2 overexpression had little impact on the expression level of the pivotal osteogenic transcription factors Runx2, Dlx5, Msx2, and Osterix, but led to upregulation of Alp and Osteocalcin (OCN), both of which play critical roles in promoting osteoblast maturation. Importantly, luciferase analysis showed that Dlx2 overexpression stimulated both OCN and Alp promoter activity. Through chromatin-immunoprecipitation assay and site-directed mutagenesis analysis, we provide molecular evidence that Dlx2 transactivates OCN and Alp expression by directly binding to the Dlx2-response cis-acting elements in the promoter of the two genes. Based on these findings, we demonstrate that Dlx2 overexpression enhances osteogenic differentiation in vitro and accelerates bone formation in vivo via direct upregulation of the OCN and Alp gene, suggesting that Dlx2 plays a crucial role in osteogenic differentiation and bone formation.
Animals ; Cell Differentiation ; physiology ; Core Binding Factor Alpha 1 Subunit ; Homeodomain Proteins ; metabolism ; Mesenchymal Stem Cells ; metabolism ; Mice ; Mice, Nude ; Osteoblasts ; metabolism ; Osteocalcin ; drug effects ; Osteogenesis ; physiology ; Transcription Factors ; metabolism ; Up-Regulation