Stem cells and development最新文献

Tooth dentin is a crucial tooth structure. The biological process of odontoblast differentiation is essential for formation of normal dentin. Accumulation of reactive oxygen species (ROS) leads to oxidative stress, which can influence the differentiation of several cells. As a member of the importin-β superfamily, importin 7 (IPO7) is essential for nucleocytoplasmic transport and plays an important role in the processes of odontoblast differentiation and oxidative stress. Nevertheless, the association between ROS, IPO7, and odontoblast differentiation in mouse dental papilla cells (mDPCs) and the underlying mechanisms remain to be elucidated. In this study, we confirmed that ROS suppressed odontoblastic differentiation of mDPCs as well as the expression and nucleocytoplasmic shuttle of IPO7 in cells, while overexpression of IPO7 can rescue these effects. ROS resulted in increased phosphorylation of p38 and cytoplasmic aggregation of phosphorylated p38 (p-p38), which was able to be reversed by overexpression of IPO7. p-p38 interacted with IPO7 in mDPCs without hydrogen peroxide (H₂O₂) treatment, but in the presence of H₂O₂, the interaction between p-p38 and IPO7 was significantly decreased. Inhibition of IPO7 increased the expression level and nuclear translocation of p53, which are mediated by cytoplasmic aggregation of p-p38. In conclusion, ROS inhibited odontoblastic differentiation of mDPCs, which is mediated by downregulation and damaged nucleocytoplasmic shuttle of IPO7.

Adult neural stem cells (NSCs) are restricted to the two neurogenic regions of the mammalian brain, where they self-renew and generate progenies of multiple lineages, including neurons, astrocytes, and oligodendrocytes. Single-cell RNA sequencing technology, which reconstructs high-resolution transcriptional landscapes, provides valuable insights into cellular heterogeneity and developmental dynamics. In this review, we overviewed recent progress in the single-cell analyses of both conventional and unconventional NSCs. We discussed the heterogeneity among the stem cell pool and characterized the transcriptional alterations in aging and brain tumors. A comprehensive understanding of NSCs in physiological and pathological settings will provide insights for the rejuvenation of the aged brain and restoration of normal brain function in multiple neurological disorders.

Adipose-derived stem cells (ASCs), as a cell therapy with considerable therapeutic potential, have received increasing attention in tissue repair, endocrine regulation, immune regulation, and aging and obesity research. Gut microbiota are present in all organisms and play important roles in the development of aging and obesity. Dysbiosis activates inflammatory pathways that may contribute to the development of aging and obesity. We used C57BL/6 J mice of different ages to carry out the experiment. Young mice were used as donors for ASC. Feces from the three groups were collected for 16sRNA sequencing to analyze the species composition of intestinal microorganisms, and then, predicted metabolic pathways by PICRUSt2 using 16s rRNA gene sequences. Immune cell levels in abdominal adipose tissue were assessed by flow cytometry. The content of IL-6, IL-1β, TNF-α, and lipopolysaccharides in serum was measured by ELISA kit. Our 16sRNA sequencing data showed restoration of gut microbiota diversity and an increase in beneficial flora (Akkermansia, Lactobacillus, Prevotella) 7 days after ASC transplantation. In addition, the inflammatory environment improved in older transplanted mice.

Peritoneal fibrosis is a critical sequela that limits the application of peritoneal dialysis (PD). This study explored the role and mechanism of bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) in preventing PD-associated peritoneal injury. C57BL/6 mice were randomized into three groups: a control (saline), peritoneal injury [2.5% glucose peritoneal dialysate + lipopolysaccharide (LPS)], and peritoneal injury + exosome group. After 6 weeks, mice were dissected, and the parietal peritoneum was collected. The level of peritoneal structural and functional damage was assessed. Additionally, transcriptome analysis of the peritoneum and miRNA sequencing on BMSC-Exos were performed. The parietal peritoneum had significantly thickened, and peritoneal function was impaired in the peritoneal injury group. Peritoneal structural and functional damage was significantly reduced after exosome treatment, while peritoneal inflammation, fibrosis, angiogenesis, and mesothelial damage significantly increased. Transcriptomic analysis showed that the BMSC-Exos affected the cell cycle process, cell differentiation, and inflammatory response regulation. Significant pathways in the exosome group were enriched by inflammation, immune response, and cell differentiation, which constitute a molecular network that regulates the peritoneal protective mechanism. Additionally, inflammatory factors (TNF-α, IL-1β), fibrosis markers (α-SMA, collagen-III, fibronectin), profibrotic cytokines (TGF-β1), and angiogenesis-related factor (VEGF) were downregulated at the mRNA and protein levels through BMSC-Exos treatment. BMSC-Exos treatment can prevent peritoneal injury by inhibiting peritoneal fibrosis, inflammation, and angiogenesis, showing a multitarget regulatory effect. Therefore, BMSC-Exos therapy might be a new therapeutic strategy for treating peritoneal injury.

Most pediatric patients with global developmental delay (GDD) or intellectual disability (ID) have disrupted development. Since allogeneic umbilical cord blood (UCB) may exert neurotrophic effects, a prospective clinical trial was conducted to assess the efficacy and safety of UCB therapy for GDD and ID. A total of 13 children (ages 23-149 months) with GDD and ID were enrolled and followed up for 12 months. Under criteria of histocompatibility and cell number, allogeneic UCB units were selected and infused once intravenously, and adverse events were monitored. The Bayley Scale of Infant Development-II (BSID-II) was used as primary outcome measurement tool, and evaluations for various functional abilities were also implemented. Safety assessment did not reveal significant adverse effects. Functional improvements in mental and motor developments along with daily living activities and languages were observed at 12 months postintervention compared with the baseline abilities (P < 0.05). Furthermore, mental developmental quotient derived from BSID-II mental scale revealed significantly facilitated improvement during the first 3 months (P < 0.05). In the survey conducted 80.7 ± 13.0 months after UCB infusion to assess satisfaction and long-term safety, no long-term adverse effects were reported, and 70% of the guardians reported satisfaction with the UCB infusion. Long-term changes in two patients who were regularly followed up beyond the study completion were noticeable. One case observed for 4 years showed dramatic improvement until 12 months after UCB therapy, whereas she showed insignificant improvement beyond 12 months after the therapy. Another case showed alleviation of autism with findings of anti-inflammatory response in his peripheral blood after UCB infusion. This clinical study provides support for further applications of UCB as a therapeutic avenue for children with GDD or ID owing to its safety and partial efficacy. Due to patient heterogeneity, further studies focusing on specific clinical manifestations and etiologies are required. Registered at www.clinicaltrials.gov (NCT01769716).

Hematopoietic stem cell (HSC)-based gene therapy has already reached clinical reality in a few applications. Fetal administration of genetically modified HSCs has only been feasible to date through invasive and morbid methods. It has been recently shown that native donor HSCs can reach the fetal circulation and bone marrow after simple delivery into the amniotic fluid, at least in a syngeneic healthy model. We sought to determine whether the transamniotic route could also be a practical alternative for the fetal administration of genetically modified HSCs in a comparable model. Pregnant Lewis rat dams underwent volume-matched intra-amniotic injections in all their fetuses (n = 47) on gestational day 17 (E17; term = E21-22) of donor HSCs genetically modified using a custom lentiviral vector designed to constitutively express both a firefly luciferase reporter gene and a human adenosine deaminase (ADA) transgene. Donor HSCs consisted of syngeneic cells isolated from the amniotic fluid and phenotyped by flow cytometry. Fetuses were euthanized at term, when seven select sites relevant to HSC-based therapies were screened for either luciferase activity by luminometry or for the presence of human ADA mRNA by digital droplet polymerase chain reaction (ddPCR). Among survivors (30/47; 64%), positive luminescence and positive human ADA expression were detected in the bone marrow (respectively, 33% and 76%), liver (respectively, 11% and 81%), spleen (respectively, 11% and 67%), thymus (respectively, 33% and 67%), lungs (respectively, 44% and 86%), and brain (respectively, 22% and 90%). Nucleated peripheral blood cells were analyzed only by ddPCR, showing positive human ADA expression at 54%. We conclude that genetically modified HSCs can reach the fetal circulation and fetal bone marrow after simple intra-amniotic administration in a syngeneic rat model. Gene therapy by transamniotic HSC delivery may become a practicable, minimally invasive strategy for the prenatal treatment of select hemoglobinopathies, immunodeficiencies, and inherited metabolic disorders.

Cellular therapy (CT) can be defined as the transference into a person of healthy cells to correct defective functions. Yesterday (1950-2010), CT consisted mostly of hematopoietic transplants for the treatment of a variety of hematological disorders. Interestingly, during that period of time other cell types with therapeutic potential-including certain lymphoid populations and other nonhematopoietic cells-were discovered and characterized; thus, CT became a promising discipline for the treatment of a broader diversity of diseases. Today (2011-2023), CT has significantly grownup through preclinical studies and clinical trials, and it is currently progressing toward its consolidation as one of the pillars of medicine in the 21st century. Indeed, different types of stem cells (e.g., hematopoietic, mesenchymal, neural, and pluripotent), as well as different lymphoid and myeloid cell populations (e.g., TILs, CAR-Ts, CAR-NKs, and DUOC-01) are being used in clinical settings or are being tested in clinical trials. For the past decade, several CT modalities have been developed, and today, many of them are being used in the clinic. Tomorrow (2024-2040), already established CT modalities will surely be improved and applied more frequently, and novel therapies (that will include cell types such as iPSCs) will enter and expand within the clinical ground. It is noteworthy, however, that despite significant advancements and achievements, problems still need to be solved and obstacles need to be overcome. Technical, ethical, and economic issues persist and they need to be addressed. Undoubtedly, exciting times of challenges and opportunities are coming ahead in the CT arena.

Many adult somatic stem cell lineages are comprised of subpopulations that differ in gene expression, mitotic activity, and differentiation status. In this study, we explored if cellular heterogeneity also exists within oogonial stem cells (OSCs), and how chronological aging impacts OSCs. In OSCs isolated from mouse ovaries by flow cytometry and established in culture, we identified subpopulations of OSCs that could be separated based on differential expression of stage-specific embryonic antigen 1 (SSEA1) and cluster of differentiation 61 (CD61). Levels of aldehyde dehydrogenase (ALDH) activity were inversely related to OSC differentiation, whereas commitment of OSCs to differentiation through transcriptional activation of stimulated by retinoic acid gene 8 was marked by a decline in ALDH activity and in SSEA1 expression. Analysis of OSCs freshly isolated from ovaries of mice between 3 and 20 months of age revealed that these subpopulations were present and persisted throughout adult life. However, expression of developmental pluripotency associated 3 (Dppa3), an epigenetic modifier that promotes OSC differentiation into oocytes, was lost as the mice transitioned from a time of reproductive compromise (10 months) to reproductive failure (15 months). Further analysis showed that OSCs from aged females could be established in culture, and that once established the cultured cells reactivated Dppa3 expression and the capacity for oogenesis. Analysis of single-nucleus RNA sequence data sets generated from ovaries of women in their 20s versus those in their late 40s to early 50s showed that the frequency of DPPA3-expressing cells decreased with advancing age, and this was paralleled by reduced expression of several key meiotic differentiation genes. These data support the existence of OSC subpopulations that differ in gene expression profiles and differentiation status. In addition, an age-related decrease in Dppa3/DPPA3 expression, which is conserved between mice and humans, may play a role in loss of the ability of OSCs to maintain oogenesis with age.

Adverse intrauterine environments can cause persistent changes in epigenetic profiles of stem cells, increasing susceptibility of the offspring to developing metabolic diseases later in life. Effective approaches to restore the epigenetic landscape and function of stem cells remain to be determined. In this study, we investigated the effects of pharmaceutical activation of AMP-activated protein kinase (AMPK), an essential regulator of energy metabolism, on mitochondrial programming of Wharton's Jelly mesenchymal stem cells (WJ-MSCs) from women with diabetes during pregnancy. Induction of myogenic differentiation of WJ-MSCs was associated with increased proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression and mitochondrial DNA (mtDNA) abundance. Inhibition of DNA methylation by 5 Azacytidine significantly increased PGC-1α expression and mtDNA abundance in WJ-MSCs, which were abolished by AMPK inhibitor Compound C (CC), suggesting an AMPK-dependent role of DNA demethylation in regulating mitochondrial biogenesis in WJ-MSCs. Furthermore, activation of AMPK in diabetic WJ-MSCs by AICAR or metformin decreased the level of PGC-1α promoter methylation and increased PGC-1α expression. Notably, decreased PGC-1α promoter methylation by transient treatment of AMPK activators persisted after myogenic differentiation. This was associated with enhanced myogenic differentiation capacity of human WJ-MSCs and increased mitochondrial function. Taken together, our findings revealed an important role for AMPK activators in epigenetic regulation of mitochondrial biogenesis and myogenesis in WJ-MSCs, which could lead to potential therapeutics for preventing fetal mitochondrial programming and long-term adverse outcome in offspring of women with diabetes during pregnancy.

Cartilage is derived from the chondrogenic differentiation of stem cells, for which the regulatory mechanism has not been fully elucidated. N6-methyladenosine (m6A) messenger RNA (mRNA) methylation is the most common posttranscriptional modification in eukaryotic mRNAs and is mediated by m6A regulators. However, whether m6A regulators play roles in chondrogenic differentiation is unknown. Herein, we aim to determine the role of a main m6A reader protein, YTH N6-methyladenosine RNA binding protein 1 (YTHDF1), in chondrogenic differentiation regulation. Western blotting (WB) assays found that the expression of YTHDF1 increased during chondrogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). The results of quantitative polymerase chain reaction, WB, immunohistochemistry, and Alcian blue staining revealed that overexpression of YTHDF1 increased cartilage matrix synthesis and the expression of chondrogenic markers when hBMSCs, ATDC5 cells, or C3H10T1/2 cells were induced to undergo chondrogenesis. Conversely, chondrogenesis was clearly inhibited when YTHDF1 was knocked down in hBMSCs, ATDC5 cells, or C3H10T1/2 cells. Further RNA sequencing and molecular biology experiments found that YTHDF1 activated the Wnt/β-catenin signaling pathway during chondrogenic differentiation. Finally, the effects of overexpression and knockdown of YTHDF1 on chondrogenic differentiation were reversed by inhibiting or activating β-catenin activity. Therefore, we demonstrated that YTDHF1 promoted chondrogenic differentiation through activation of the Wnt/β-catenin signaling pathway.