Long non-coding RNA (LncRNA) plays an important role in nervous system development and neurological diseases. Previous studies by the research team have demonstrated that human umbilical cord mesenchymal stem cells overexpressing erythropoietin (EPO-MSCs) under ischemic and hypoxic conditions have better neuroprotective functions and significantly activate the expression of LncRNA XIST. Research suggests that XIST is related to the pathogenesis of hypoxic-ischemic encephalopathy, but the role and mechanism of its regulation by EPO-MSCs in protecting ischemic-hypoxic neurons remain unclear.

To explore the new mechanism by which LncRNA XIST, in response to EPO-MSC signaling, affects the apoptosis of ischemic-hypoxic SH-SY5Y cells.

(1) SH-SY5Y cell lines with knockdown of LncRNA XIST (sh-XIST) and negative control (NC-XIST) were constructed through lentiviral transfection. Oxygen-glucose deprivation was used to induce ischemic-hypoxic injury in the cells. Transwell chambers were used to create a non-contact co-culture system with EPO-MSCs, sh-XIST, and NC-XIST ischemic-hypoxic SH-SY5Y cells. Cell proliferation ability was detected using the CCK-8 assay. Cell migration ability was assessed using the scratch assay, and cell apoptosis was measured by flow cytometry. (2) RNA-seq bioinformatics analysis was performed to screen for differentially expressed genes and pathways between sh-XIST and NC-XIST cell lines. Dual-luciferase experiments were used to verify the relationship between miR-124-3p and the target genes XIST and GRIN1. qRT-PCR was conducted to validate the expression levels of downstream miR-124-3p and GRIN1 genes. (3) miR-124-3p inhibitors and mimics were added to verify phenotypic changes in SH-SY5Y cells after ischemic-hypoxic injury and co-culture with EPO-MSCs.

(1) Compared with the NC-XIST group, SH-SY5Y cells in the sh-XIST group showed reduced proliferation and migration abilities and increased apoptosis after ischemic-hypoxic injury and co-culture with EPO-MSCs. (2) Dual-luciferase experiments showed that miR-124-3p interacted with the target gene XIST. SH-SY5Y cells transfected with miR-124-3p mimics and co-cultured with EPO-MSCs showed decreased apoptosis after ischemic-hypoxic injury, while SH-SY5Y cells transfected with miR-124-3p inhibitors showed increased apoptosis after co-culture with EPO-MSCs. (3) Transcriptomic sequencing and bioinformatics analysis of sh-XIST revealed significant downregulation of the neuroactive ligand-receptor pathway and the key receptor gene GRIN1 for central nervous system development. (4) Dual-luciferase experiments showed that miR-124-3p interacted with GRIN1. GRIN1 expression was significantly downregulated in the sh-XIST group after ischemic-hypoxic injury compared with the NC-XIST group. These findings indicate that LncRNA XIST promotes GRIN1 expression by upregulating miR-124-3p, thereby reducing cell apoptosis after ischemic-hypoxic injury and co-culture with EPO-MSCs and enhancing proliferation and migration. sh-XIST can block this protective function.

Hepatocyte-like cells induced by mesenchymal stem cells are promising seed cells for liver regeneration or liver tissue engineering. The efficiency of traditional two-dimensional culture for hepatocyte induction is low, and more and more research is focused on three-dimensional culture for inducing hepatocyte differentiation.

To summarize three-dimensional culture models for the hepatic induction of mesenchymal stem cells, focus on research progress on the epigenetic regulation mechanisms of mesenchymal stem cell hepatogenic differentiation, providing a theoretical basis for improving the differentiation efficiency of mesenchymal stem cells.

Relevant articles in the PubMed and other databases such as CNKI were searched, using Chinese and English search terms “mesenchymal stem cell, 3D culture, hepatogenic differentiation, hepatocyte-like cells, epigenetics.” Additionally, the literature tracing method was employed to find some of the literature for a comprehensive review and analysis.

(1) Common three-dimensional culture models for the hepatogenic differentiation of mesenchymal stem cells currently include spheroids, biological scaffolds, bioprinting, and microfluidic chips. Each of these models has its own advantages and disadvantages in the process of inducing hepatogenic differentiation. (2) During the differentiation of mesenchymal stem cells into hepatocyte-like cells, epigenetic regulation plays a key role, primarily involving histone modification, DNA methylation, and the regulation of non-coding RNAs. (3) Under three-dimensional culture conditions, epigenetic modifications, especially histone acetylation, play an important role in promoting the hepatogenic differentiation of mesenchymal stem cells.

Previous studies have found that growth arrest and DNA damage-inducible protein 45β (Gadd45b) is beneficial to the repair of acute cerebral ischemia, but the action mechanism is still unclear.

To investigate the effect and mechanism of Gadd45b on white matter demyelinating lesions in rats with chronic cerebral ischemia.

SD rats were randomly divided into four groups: sham operation group, model group, empty vector group, and Gadd45b overexpression group, with 15 rats in each group. Gadd45b-overexpressing lentivirus and no-load lentivirus were injected into the bilateral hippocampus and bilateral ventricles of rats. One week after lentivirus transfection, the rat model of chronic hypoperfusion cerebral ischemia was established by bilateral common carotid artery ligation. Three weeks after the bilateral common carotid artery ligation, the learning and cognitive functions of rats were evaluated by novel object recognition test. Luxol fast blue staining was used to observe the changes of myelin structure in the corpus callosum of rats. Hematoxylin-eosin staining and Nissl staining were used to observe the damage of the rat corpus callosum. Immunofluorescence staining was used to detect the expression of myelin basic protein and neurofilament protein 200 in the corpus callosum of rats. Immunofluorescence double staining was used to detect the expression of astrocyte markers GFAP/C3d and GFAP/S100A10 in rat brain tissue. ELISA was used to detect the levels of tumor necrosis factor-α and interleukin-6 in the supernatant of brain tissue.

(1) Gadd45b overexpression could significantly improve the learning and cognitive function of rats with chronic cerebral ischemia, and improve demyelination and pathological damage in the rat corpus callosum. (2) The results of immunofluorescence showed that Gadd45b overexpression significantly increased the expression levels of myelin basic protein and neurofilament protein 200 in the brain tissue of rats with chronic cerebral ischemia. (3) Gadd45b overexpression reduced GFAP/C3d double positive cells and increased GFAP/S100A10 double positive cells in the brain tissue of rats with chronic cerebral ischemia. (4) Gadd45b overexpression reduced the levels of tumor necrosis factor-α and interleukin-6 in the brain tissue of rats with chronic cerebral ischemia. It is concluded that Gadd45b overexpression improves cognitive dysfunction by promoting the A2 phenotype transformation of astrocytes, alleviating white matter myelin structure damage and neuroinflammation in rats with chronic cerebral ischemia.

Currently, spinal cord injury imposes a huge psychological and economic burden on patients and the National Health Service. The prevention, treatment, and rehabilitation of spinal cord injury have become an important topic in the field of medicine. Therefore, it is important to explore new effective therapeutic strategies based on an in-depth understanding of the underlying molecular mechanisms of spinal cord injury.

To review the research progress on the mechanism of action of mesenchymal stem cell-derived exosomes loaded with various miRNAs in improving the function of spinal cord injury, and based on the current status of clinical translation, to put forward a few thoughts and outlooks on their clinical use.

The first author searched CNKI and PubMed databases using “mesenchymal stem cells, exosomes, spinal cord injury, miRNA, pathophysiology, clinical translation, clinical trials, good manufacturing practice” as Chinese and English search terms. The types of literature included treatises and reviews, and the language types were English and Chinese. Finally, 72 papers were screened and analyzed.

(1) This article outlines the biological properties of exosomes and the advantages that they can serve as good vectors for loading miRNAs. A variety of miRNAs mediated by mesenchymal stem cell-derived exosomes mainly promote the recovery of neuronal function by regulating the expression of nerve regeneration-associated proteins, repressing RAS homologous gene family member A, activating cyclophosphoadenosine effector-binding proteins, and signaling and transcriptional activation proteins 3, and regulating phosphoinositide and tensin homologue/programmed cell death factor 4 pathways. Inflammatory responses were improved by regulating endoplasmic reticulum-to-nucleus signaling 1, expression of interferon regulatory factor 5, Toll-like receptor 4/nuclear factor-kappa B pathway, and down-regulating related pro-inflammatory factors. Angiogenesis was promoted by inhibition of germination-associated domain 1-containing EVH1 and phosphatidylinositol 3-kinase regulatory subunit 2. (2) Further comparative analyses revealed that miR-216-5p, miR-145-5p, and miR-146b improved inflammatory responses by regulating related pathways. Combining these miRNAs may produce more significant effects; hypoxic preconditioning may be a preconditioning method to increase the efficacy of exosomal therapy. (3) There are currently no clinical trials applying mesenchymal stem cell-derived exosomes to spinal cord injury, which is related to the need to meet good manufacturing practices before they can be put into clinical use. Challenges such as the need for large-scale, high-volume cell production, the lack of an efficient and uniform method for isolating exosomes, and the need to pass a strict regulatory approval mechanism prior to clinical use have impeded the clinical entry. (4) miRNAs have great potential as exosomal contents of mesenchymal stem cells in the treatment of spinal cord injury, and their mechanism of action should be explored in depth as well as accelerated to the clinical trial stage in order to provide a new and effective method for the treatment of spinal cord injury.

With aging, the regenerative capacity and differentiation function of bone marrow mesenchymal stem cells progressively decline, reducing bone tissue repair efficacy. Thus, identifying bone marrow mesenchymal stem cell subpopulations with enhanced osteogenic potential is of significant importance for advancing bone tissue engineering.

To evaluate the osteogenic differentiation potential differences between STRO-1 positive and negative bone marrow mesenchymal stem cells under osteogenic induction conditions.

SD rat bone marrow mesenchymal stem cells were isolated and cultured. The expression of CD29, CD45, CD90, and STRO-1 was identified via flow cytometry and immunofluorescence. Immunomagnetic cell sorting was used to separate STRO-1 positive and negative bone marrow mesenchymal stem cells. The cells of two groups were subjected to osteogenic induction for 7 and 14 days. qRT-PCR and western blotting were performed to analyze differences in osteogenesis-related gene expression (Collagen I, Runt-related transcription factor 2, osteoprotegerin, and osteocalcin) and protein levels. Alizarin red staining and alkaline phosphatase staining were used to observe calcium nodule formation.

Flow cytometry showed high expression levels of CD29 and CD90 and low expression of CD45, with a positive STRO-1 expression rate of 12.8%. Immunofluorescence results were consistent with those of flow cytometry. After magnetic cell sorting, STRO-1 positive cells demonstrated a higher colony formation rate than STRO-1 negative cells. On day 14, STRO-1 positive cells showed significantly higher osteogenic differentiation potential than on day 7, with significantly elevated osteogenesis-related marker levels compared to STRO-1 negative cells (P < 0.01). The findings indicate that STRO-1 positive bone marrow mesenchymal stem cells exhibit significant advantages in osteogenic potential, providing a theoretical basis for their selection as ideal seed cells in bone tissue engineering. In future applications, they may represent a promising therapeutic approach for bone defect repair.

Premature ovarian failure has manifested a trend of younger, and stem cell therapy has been progressively implemented in clinical practice in recent years. Nevertheless, given the extensive range of sources and variegated existence of stem cells in diverse tissues, certain disparities prevail in their biological characteristics and functions. In this paper, the therapeutic efficacies of dissimilar sources of mesenchymal stem cells on animal models of premature ovarian failure were contrasted, with the aim of providing a basis for the clinical application of stem cells.

The animal model experiments of mesenchymal stem cell therapy for premature ovarian failure were retrieved from PubMed, The Cochrane Library, and EMbase, as well as Chinese databases such as CNKI, WanFang, VIP, and China Biomedical Literature Service. The search period extended from the inception to December 31, 2023. Two researchers independently screened the literature, extracted and analyzed the data. The quality of the included studies was evaluated by means of the SYRCLE animal experiment bias risk assessment table. Main outcome measures: Follicle stimulating hormone, estradiol, luteinizing hormone, the quantity of follicles at all levels. Secondary outcome measure: Pregnancy rate. Network meta-analysis, mapping, and tabulation were executed using Stata 17.0 software after assessing the risk of bias in the included studies.

Totally 24 animal experiment studies were incorporated, and the overall quality of the literature was mediocre, encompassing 7 distinct sources of mesenchymal stem cells. They were umbilical cord-derived mesenchymal stem cells, menstrual blood-derived mesenchymal stem cells, placenta-derived mesenchymal stem cells, human cord blood-derived mesenchymal stem cells, bone marrow-derived mesenchymal stem cells, adipose-derived mesenchymal stem cells, and amnio-derived mesenchymal stem cells. The network meta-analysis demonstrated that (1) in contrast to the blank group, mesenchymal stem cells from various sources were effective in enhancing the pregnancy rate and estradiol, reducing follicle-stimulating hormone and luteinizing hormone, augmenting the number of follicles at all levels, and diminishing the number of atretic follicles. (2) According to the area map under the cumulative sequencing curve, the three stem cells with the most prominent efficacy in improving estradiol levels were umbilical cord-derived mesenchymal stem cells (72.7%) > adipose-derived mesenchymal stem cells (72.6%) > menstrual blood-derived mesenchymal stem cells (71.7%). (3) The three kinds of stem cells with the highest efficacy in reducing follicle-stimulating hormone levels were the adipose-derived mesenchymal stem cells (96.3%) > human cord blood-derived mesenchymal stem cells (65.4%) > umbilical cord-derived mesenchymal stem cells (63.9%). (4) The three kinds of stem cells with the highest efficacy in reducing luteinizing hormone levels were adipose-derived mesenchymal stem cells (100.0%) > umbilical cord-derived mesenchymal stem cells (51.6%) > human cord blood-derived mesenchymal stem cells (46.8%). (5) The top three kinds of stem cells for increasing the number of primordial follicles were human cord blood-derived mesenchymal stem cells (76.3%) > umbilical cord-derived mesenchymal stem cells (75.5%) > menstrual blood-derived mesenchymal stem cells (57.5%). (6) The top three kinds of stem cells for increasing the number of primary follicles were umbilical cord-derived mesenchymal stem cells (75.3%) > adipose-derived mesenchymal stem cells (53.0%) > the placenta-derived mesenchymal stem cells (51.7%). (7) The top three kinds of stem cells for increasing the number of secondary follicles were adipose-derived mesenchymal stem cells (76.1%) > menstrual blood-derived mesenchymal stem cells (66.8%) > umbilical cord-derived mesenchymal stem cells (66.5%). (8) The top three kinds of stem cells in reducing the number of atretic follicles were adipose-derived mesenchymal stem cells (99.9%) > bone marrow-derived mesenchymal stem cells (68.1%) > umbilical cord-derived mesenchymal stem cells (53.4%).

(1) For animal models of premature ovarian failure, the results of the network meta-analysis disclosed that various stem cell transplantation treatments were preponderant over the blank or placebo group to varying extents, and the efficacies were comparable. (2) The results indicated that umbilical cord-derived mesenchymal stem cells were the most frequently utilized and adipose-derived mesenchymal stem cells were the most potent. More high-quality experimental study data are requisite in the future for further validation.

Long noncoding RNA TP53TG1 (lncRNA TP53TG1) is involved in regulating the proliferation, migration, invasion, and apoptosis of various cancer cells, but there are few reports on its role in other cells.

To investigate the effects and pathways of lncRNA TP53TG1 on the proliferation and differentiation of human stem cells from the apical papilla.

Human stem cells from the apical papilla were isolated and cultured, and then transfected with lncRNA TP53TG1 overexpression lentivirus. RT-qPCR was used to detect the overexpression efficiency of lncRNA TP53TG1. Western blot assay was used to detect the relative expression levels of PI3K, AKT, ERK, P38, Smad3, and their phosphorylated proteins. Human stem cells from the apical papilla were divided into the empty lentiviral vector transfection group and the lncRNA TP53TG1 overexpression group. CCK-8 assay was used to measure the cell proliferation. Alkaline phosphatase activity was detected by alkaline phosphatase staining on day 5 of osteogenic induction. Formation of mineralized nodules was detected by alizarin red staining on day 21 of osteogenic induction. RT-qPCR was used to detect the mRNA expression levels of dentin sialophosphoprotein, Runt-related transcription factor 2, dentin matrix protein 1, and bone sialoprotein on days 3, 7, and 14 of osteogenic induction. Western blot assay was used to detect the protein expression levels of dentin sialophosphoprotein and Runt-related transcription factor 2 on days 3, 7, and 14 of osteogenic induction.

(1) RT-qPCR results showed that the lentivirus was successfully integrated into the genome of stem cells from the apical papilla. Western blot assay results showed that overexpression of lncRNA TP53TG1 up-regulated the protein levels of p-PI3K and p-AKT without affecting the expression of phosphorylated proteins in other pathways. (2) Starting from day 3 of cell culture, overexpression of lncRNA TP53TG1 significantly promoted the proliferation of stem cells from the apical papilla. (3) In the process of inducing odontogenic differentiation of stem cells from the apical papilla, overexpression of lncRNA TP53TG1 promoted the expression of odontogenic and osteogenic differentiation-related genes and proteins, significantly increased alkaline phosphatase activity and mineralized nodule formation. (4) The results show that lncRNA TP53TG1 may promote the odontogenic and osteogenic differentiation of stem cells from the apical papilla by activating the PI3K/AKT signaling pathway.

Enhancing the differentiation of induced pluripotent stem cells into lung stem cells is crucial for repairing lung injuries. NKX2.1 is the earliest marker of lung epithelial differentiation and plays a significant regulatory role in lung development. However, the impact of its expression on the differentiation of induced pluripotent stem cells into lung stem cells remains inadequately understood.

To investigate the effect of NKX2.1 on the differentiation of induced pluripotent stem cells into lung stem cells.

Induced pluripotent stem cells were cultured in vitro. The expression of specific pluripotent stem cell genes was assessed using real-time fluorescence quantitative PCR. NKX2.1 was overexpressed in induced pluripotent stem cells, which were then induced to differentiate into lung stem cells. The expression of FoxA2, SOX9, and P63 was determined via quantitative PCR and immunofluorescence on day 7 of induction of differentiation. The expression of the alveolar marker SPB and SPC was evaluated through immunofluorescence staining on day 7 of induction of differentiation.

(1) Induced pluripotent stem cells in vitro were tightly packed and showed typical clonoid growth and significantly expressed stem cell-specific genes OCT-4, SOX2, and NANOG. (2) Compared with the non-transfected control group, the expression of NKX2.1 in human induced pluripotent stem cells was significantly increased in the NKX2.1 overexpression group (P < 0.000 1). (3) Seven days after induction of differentiation, compared with the non-transfected control group, the expression of lung stem cell-related markers FoxA2, SOX9, and P63 was significantly increased in the NKX2.1 overexpression group (P < 0.000 1). (4) Thirteen days after induction of differentiation, compared with the non-transfected control group, the fluorescence intensity of alveolar cell marker molecules SPB and SPC increased significantly in the overexpression NKX2.1 group. The results show that NKX2.1 can promote the differentiation of induced pluripotent stem cells into lung stem cells.

Accurate early diagnosis and timely reperfusion therapy are important prerequisites for saving the lives and improving the prognosis of patients with acute myocardial infarction. Therefore, it is important to find ideal biomarkers for early diagnosis of acute myocardial infarction.

To analyze key genes associated with neutrophils by acute myocardial infarction through bioinformatics and machine learning to explore new biomarkers.

Differentially expressed genes were identified based on the Gene Expression Omnibus (GEO) database and Limma R package. Deconvolution algorithm was used to explore the immune cells infiltration level. Then, acute myocardial infarction and neutrophils-related biomarkers were screened by weighted gene co-expression network analysis (WGCNA), protein-protein interaction (PPI) networks, machine learning, and functional enrichment analysis. Receiver operating characteristic curve analysis was conducted to assess the diagnostic efficacy of biomarkers for acute myocardial infarction. Targeted drugs for biomarkers were screened through the STITCH and Herb database. Finally, the hospitalized patients who were first diagnosed with acute myocardial infarction in the Department of Cardiology of Affiliated Hospital of Guizhou Medical University from March to June 2023 were used as the experimental group, and the hospitalized patients who had no ischemic changes on electrocardiograms and no stenosis on coronary angiograms during the same period were used as the control group. Peripheral blood of the patients in the two groups was collected. The relative expressions of the genes were verified in the human peripheral blood samples by RT-qPCR.

(1) A total of 2 349 differentially expressed genes were obtained, and immune infiltration analysis revealed differences in immune cell scores such as B cells memory, NK cells resting, and Neutrophils between the disease and normal groups. (2) Using WGCNA, two gene modules, ME green and ME turquoise, were found to exhibit the highest correlation with neutrophil fine with acute myocardial infarction. (3) Twenty-four differential module genes were obtained after intersecting with differentially expressed genes. Functional enrichment analysis revealed that they were associated with a variety of processes such as innate immune response and defense response to bacteria. KEGG results showed that they were mainly associated with the tumor necrosis factor signaling pathway. (4) The genes mined by the machine learning algorithm took the intersection to obtain three genes, namely, S100A12, PTCH1, and LOC400499, all of which were greater than 0.7 by the area under the receiver operating characteristic curve in both the GSE48060 and GSE66360 datasets. They were considered as potential biomarkers. (5) Based on the STITCH and Herb databases, 11 target drugs were found for S100A12 and a total of 6 target drugs were found for PTCH1. (6) RT-qPCR results showed that S100A12, PTCH1, and LOC400499 were significantly differentially expressed in acute myocardial infarction patients compared with controls (P < 0.05). (7) S100A12, PTCH1, and LOC400499 may be potential diagnostic biomarkers for acute myocardial infarction, but their specificity in relation to acute myocardial infarction needs to be further investigated, in which S100A12 may be a potential target for regulating acute myocardial infarction.

Human umbilical cord mesenchymal stem cell-derived exosomes were found to be effective in promoting neural repair in spinal cord injury.

To investigate whether exosomes derived from human umbilical cord mesenchymal stem cells are able to attenuate neuroinflammation and promote recovery of motor function by promoting polarization of microglia toward the M2 type.

Totally 48 SD rats were randomly divided into a sham operation group, a model group, and an exosome group (n=16 per group). A rat spinal cord injury model was established using the modified Allen method. The exosome group was injected with 20 μL of human umbilical cord mesenchymal stem cell-derived exosomes intrathecally via neuroendoscopy 24 hours after injury. At 3, 7, 14, and 21 days after modeling, the recovery of the motor function of the hind limbs of the rats was assessed by BBB scoring method combined with Rivlin's slant plate test. The damage of spinal cord tissues was detected by using hematoxylin-eosin staining and Nissl staining. The expression levels of brain-derived neurotrophic factor and vascular endothelial growth factor A proteins were detected by western blot assay. The expression proportion of M1-type markers (inducible nitric oxide synthase) and M2 markers (arginase-1) in the spinal cord tissues was detected by immunofluorescence method. qRT-PCR and western blot assay were used to detect the expression levels of inducible nitric oxide synthase and arginase-1 in spinal cord tissues. ELISA was utilized to detect the levels of pro-inflammatory factors (tumor necrosis factor α, interleukin 1β, and interleukin 6) and anti-inflammatory factors (interleukin 10) levels in spinal cord tissues.

(1) At 3, 7, and 14 days postoperatively, the BBB scores of the exosome group were better than those of the model group (P < 0.05). The angles of the Rivlin slanting plate experiments of the exosome group were significantly higher than those of the model group at 7 and 14 days postoperatively (P < 0.05). The results of hematoxylin-eosin staining and Nissl staining indicated that the spinal cord tissues and nerve injuries of the exosome group were reduced in comparison with those of the model group, and the levels of brain-derived neurotrophic factor and vascular endothelial growth factor A in spinal cord tissues of the exosome group were higher than those in the model group at 7 days postoperatively (P < 0.05). (2) Immunofluorescence experiments showed that the number of inducible nitric oxide synthase-positive microglial cells in the lesion area of the exosome group was significantly reduced and the level of Arg1-positive microglial cells increased in the lesion area of the exosome group compared with the model group at 7 days postoperatively (P < 0.05). qRT-PCR and western blot assay also confirmed the results of immunofluorescence experiments. (3) The secretion of pro-inflammatory factors tumor necrosis factor α, interleukin 1β, and interleukin 6 in spinal cord tissues of the exosome group was reduced compared with the model group (P < 0.05), whereas the secretion of the inflammation-suppressing factor interleukin 10 was increased compared with the model group (P < 0.05). These findings conclude that human umbilical cord mesenchymal stem cell-derived exosomes could promote the polarization of microglial cells from the M1 to the M2 type and decrease the release of pro-inflammatory factors, thereby reducing the secondary damage of neuroinflammation in spinal cord injury.