Exosomes have been confirmed to be closely related to cartilage degeneration in osteoarthritis. However, the role and mechanism of exosome-derived genes in cartilage degeneration of osteoarthritis have not been fully elucidated.

Bioinformatics analyses were used to screen the genes related to cartilage degeneration in the synovial exosomes of patients with osteoarthritis, and to determine their biological functions and signaling pathways in order to provide new therapeutic targets for delaying cartilage degeneration in osteoarthritis.

Firstly, osteoarthritis-related exosome dataset GSE185059 and cartilage degeneration dataset GSE114007 were downloaded from Gene Expression Omnibus (GEO) database to screen exosome-derived cartilage degeneration related genes. GO functional and KEGG pathway enrichment analyses were performed based on the screened exosome-derived cartilage degeneration related genes. Protein-protein interaction network was drawn and Ingenuity Pathway Analysis (IPA) was conducted to screen and obtain key exosome-derived cartilage degeneration-related genes. Finally, qRT-PCR was used to verify the expression of key genes in osteoarthritis cartilage tissue and interleukin-1β stimulated chondrocyte models.

(1) There were 831 differentially expressed genes in the GSE185059 dataset and 5 323 differentially expressed genes in the GSE114007 dataset. A total of 94 exosome-derived cartilage degeneration related genes were screened after the intersection of these differentially expressed genes, of which 51 genes were down-regulated and 43 genes were up-regulated. (2) GO functional enrichment analysis showed that the up-regulated genes were mainly involved in the positive regulation of cell-cell adhesion, the positive regulation of T cell activation, and chronic inflammatory response, while the down-regulated genes were mainly involved in biological processes such as cell aggregation, cartilage differentiation and development, and skeletal system morphogenesis. (3) KEGG pathway enrichment analysis showed that exosome-derived cartilage degeneration-related genes were mainly involved in tryptophan enrichment metabolism, vitamin B6 metabolism, and leukocyte transendothelial migration. (4) The constructed protein-protein interaction network confirmed the existence of multiple interaction relationships among exosome-derived cartilage degeneration-related genes. Combined with five algorithms in CytoHubba software, four key exosome-derived cartilage degeneration-related genes were further screened, namely THY1, CYP1A1, NFKB2, and COL6A3. (5) The results of qRT-PCR showed that compared with normal cartilage, the expressions of THY1 and COL6A3 in osteoarthritic cartilage were increased, while the expression of CYP1A1 and NFKB2 was decreased. Similarly, compared with the unstimulated group, the expression of THY1 and COL6A3 in the interleukin-1β induced chondrocytes was upregulated, while the expression of CYP1A1 and NFKB2 was downregulated. (6) These results indicate that THY1, CYP1A1, NFKB2, and COL6A3 are genes related to cartilage degeneration in the exosomes of synovial fluid of patients with osteoarthritis, and may participate in the pathogenesis of osteoarthritis by regulating biological processes such as protein tyrosine kinase activity and lipid metabolism, as well as nuclear factor-κB signaling pathway and focal adhesion signaling pathway. However, the specific regulatory roles and molecular mechanisms of these key genes in cartilage degeneration need to be further verified by experiments.

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.

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.

Radiotherapy for head and neck tumors can easily cause xerostomia, seriously affecting the quality of life of patients. In recent years, engineered stem cells and their paracrine factors have shown therapeutic potential in the repair of salivary gland injury. However, there is currently no experimental study on the application of amniotic mesenchymal stem cell-derived exosome in radiation-induced salivary gland injury.

To preliminarily explore the repair effect of exosome derived from human amniotic mesenchymal stem cells on radiation-induced submandibular gland injury.

Human amniotic mesenchymal stem cell exosomes were extracted and identified by ultrafiltration and ultracentrifugation. SD rats were randomly divided into a control group, a radiation injury group, and a radiation injury+exosome group. An in vitro model of radiation-induced submandibular gland injury was constructed using the submandibular gland tissue of SD rats irradiated with 18 Gy of radiation. One day after radiation modeling, exosome derived from human amniotic mesenchymal stem cells was injected into the submandibular gland in situ. Samples are taken at 1, 3, 7, and 14 days to detect the resting salivary flow rate. The structure of the submandibular gland tissue was observed by hematoxylin-eosin staining. The expression of glycogen particles in the submandibular gland tissue was observed by Periodic Acid-Schiff staining. Fibrosis in the submandibular gland tissue was observed by Masson staining. The secretion of salivary amylase was detected by enzyme-linked immunosorbent assay. The expression of aquaporin and tight junction proteins in submandibular gland tissue was observed by immunofluorescence staining. Real-time fluorescence quantitative PCR was used to detect the relative expression levels of aquaporins and salivary amylase mRNA in submandibular gland tissue. TUNEL assay was used to detect the apoptosis rate of submandibular gland tissues in each group.

After radiomodeling, compared with the radiation injury group, (1) hematoxylin-eosin staining observed that the submandibular gland tissue structure in the radiation injury+exosome group was restored, the nucleoli increased, the number of acinus increased, and the acinar atrophy improved. (2) Glycogen staining observed that the number and density of positive zymogen granules in the acinar cytoplasm of the radiation injury+exosome group gradually increased. (3) Masson staining results observed that the number and density of positive collagen fibers in the interstitium and around the ducts in the radiation injury+exosome group gradually decreased, the degree of fibrosis decreased, and the collagen deposition decreased. (4) The salivary flow rate in the radiation injury+exosome group increased (P < 0.05). The fluorescence intensity of aquaporin-5 was enhanced (P < 0.05) and the gene expression was significantly enhanced (P < 0.01). The fluorescence distribution of tight junction protein 4 was weakened and the fluorescence intensity decreased (P < 0.05, P < 0.01). The content of salivary amylase increased (P < 0.05) and gene expression were significantly increased (P < 0.01). The number of positive apoptotic cells decreased (P < 0.05, P < 0.01). It is indicated that local injection of exosome derived from human amniotic mesenchymal stem cells could improve the pathological morphology of submandibular gland tissue, promote saliva flow rate and amylase expression, and may play a functional repair role in radioactive submandibular gland injury by inhibiting acinar apoptosis.

The cryopreservation technology enables tissues/cells to be stored for a long time in a low-temperature environment while maintaining the integrity of their activity and function, which is of great significance for the construction of cell therapy, tissue engineering and biological sample banks. Cryoprotective agents often contain dimethyl sulfoxide and serum. To avoid the toxic side effects of dimethyl sulfoxide, the complexity of serum components and immune responses, although some finished cryoprotective agents have been marketed, they are faced with many difficulties such as high cost and limited application. Therefore, there is an urgent need to develop a cryoprotective agent with clear components and the ability to solve the above problems.

To evaluate the effects of a novel cryoprotectant on cryopreservation efficiency of different tissue and cell sources.

By applying the novel cryoprotectant as an experimental group with the commercially available and widely used cryoprotectant (control group) to umbilical cord Wharton's jelly tissue, umbilical cord mesenchymal stem cells, umbilical cord blood/peripheral blood mononuclear cells, NK and CIK cells, comparative analyses were conducted in terms of cell morphology, number, viability, surface markers, differentiation potential, and cell-killing toxicity assay before cryopreservation and after resuscitation thawing. We confirmed the cryopreservation effect of the new cryoprotectant and its potential application value.

(1) The novel cryoprotectant facilitated the normal growth of cryopreserved Wharton's jelly tissue upon recovery, exhibiting mesenchymal stem cell morphology. No significant differences were observed between the experimental and control groups in terms of cell recovery rate, surface markers, and differentiation potential. (2) There was no significant difference in the number and viability of cells between the experimental group and the control group after cryopreservation of cord blood/peripheral blood mononuclear cells, and the cryo-resuscitated cell numbers and viability of derived NK cells/CIK cells did not show significant difference between the experimental and control groups. (3) For NK cells derived and differentiated from cord blood/peripheral blood mononuclear cells, there was no significant difference in the proportion of CD56⁺CD16⁺ cell subpopulations between the experimental group and the control group. For CIK cells derived and differentiated from cord blood/peripheral blood mononuclear cells, there was no significant difference in the proportions of CD3⁺CD8⁺ and CD3⁺CD56⁺ cell subpopulations between the experimental group and the control group. (4) In terms of cytotoxicity testing, when the effective-target ratio of immune cells and melanoma cell line Mel624 was 20:1, whether it was NK cells/CIK cells derived from cord blood or peripheral blood mononuclear cells, there was no significant difference in the tumoricidal activity of cells between the experimental group and the control group. These findings suggest that the novel cryoprotectant can replace existing commercially available and widely used cryoprotectants, and is applicable to Wharton's jelly tissue, umbilical cord mesenchymal stem cells, umbilical cord blood/peripheral blood mononuclear cells, as well as NK and CIK cells, providing a solid technical foundation for the scaling, standardization, and commercialization of universal cryoprotectants.

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.

Extracellular vesicles have received extensive attention in the field of bone defect regeneration and repair in recent years. However, natural extracellular vesicles have deficiencies in sustained controlled release, tissue targeting, and drug loading capacity. Therefore, the introduction of engineering strategies to modify extracellular vesicles to enhance their therapeutic efficacy has become a research hotspot.

To review the role and application progress of engineered extracellular vesicles in the regeneration and repair of bone defects.

PubMed, Web of Science, CNKI, and WanFang databases were searched for relevant articles published in the past fifteen years. The search terms were “engineering, extracellular vesicles, exosomes, bone defect, bone regeneration, bone repair” in Chinese and English. After removal of poorly related, outdated, and duplicate studies by screening, 93 articles were finally included for review according to inclusion criteria.

(1) Extracellular vesicles are primarily isolated based on their density, size, immunoaffinity, and surface charge. After isolation, extracellular vesicles are characterized using imaging techniques, size- and counting-based techniques, and flow cytometry. (2) Extracellular vesicles stimulate bone regeneration by regulating immunity, angiogenesis, and proliferation and differentiation of target cells. (3) The engineering strategies of extracellular vesicles include surface modification and cargo loading. (4) The introduction of bone morphogenetic protein 2, mutant hypoxia-inducible factor-1α, vascular endothelial growth factor, miRNA and other bioactive factors into extracellular vesicles through engineering strategies can enhance their regenerative repair ability for bone defects.

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.

Human pluripotent stem cell-derived cardiomyocytes offer an ideal cellular resource for studying heart diseases, conducting drug screening, developing in vitro heart models, and exploring potential cell therapies. However, human pluripotent stem cell-derived cardiomyocytes are characterized by immaturity with limited specific gene expression, low Ca²⁺ processing levels, and underdeveloped structural, metabolic, and electrophysiological features. These limitations significantly impede the application of human pluripotent stem cell-derived cardiomyocytes.

To review the academic progress and clinical application of promoting the maturation of human pluripotent stem cell-derived cardiomyocytes by in vitro synthetic microenvironment.

CNKI, WanFang, VIP, PubMed, Web of Science, and Medline databases were searched, with “human pluripotent stem cells, human myocardial cells, hPSC-CMs, mature, OA, human pluripotent stem cell-derived cardiomyocytes, hPSC-CMs” as English search terms and “human pluripotent stem cells, cardiomyocytes, mature, OA, hPSC-CMs” as Chinese search terms. All relevant literature published from January 2002 to July 2024 was retrieved and 82 articles were included in the review.

(1) In recent years, in vitro synthetic microenvironments have attracted extensive attention due to their excellent intrinsic properties such as stiffness, plasticity, nanoscale morphology, and chemical functionality. (2) Human pluripotent stem cell-derived cardiomyocytes can be used as an effective platform for the treatment of cardiovascular diseases. (3) Mechanical stimulation, electrical stimulation, addition of biochemical molecules, and three-dimensional culture methods are effective methods to promote the maturation of human pluripotent stem cell-derived cardiomyocytes, which can further promote the clinical application of human pluripotent stem cell-derived cardiomyocytes.

Hematopoietic stem cell transplantation is a widely used treatment method to cure malignant and nonmalignant diseases originated from hematological cells. Mobilization and collection of sufficient hematopoietic stem cells are the preconditions to ensure rapid and sustained hematopoietic reconstitution after hematopoietic stem cell transplantation. However, the most commonly used granulocyte colony-stimulating factor with or without chemotherapy still has a mobilization failure rate of 10% to 40%.

To review the present status of hematopoietic stem cell mobilization in recent years, analyze the advantages and disadvantages of different mobilization plans, and be looking forward for new mobilization methods.

Using “hematopoietic stem cell, hematopoietic stem cell transplantation, hematopoietic stem cell mobilization, cytokines, thrombopoietin, CXCR4 antagonists, integrin antagonist, chemotherapy, mobilization efficiency” as Chinese and English keywords, articles published from 1990 to 2024 were searched on CNKI, PubMed, and WanFang databases. A total of more than 300 articles were retrieved, and 68 articles were finally included.

More and more studies have found that granulocyte colony-stimulating factor combined with other agents including plerixafor, interleukins, thrombopoietin, and integrin antagonist could improve hematopoietic stem cell mobilization. Combined use can reduce the dose of granulocyte colony-stimulating factor and related adverse reactions. Some new drugs, such as soluble recombinant FLT3-ligand (CDX-301) and dual α9β1/α4β1 integrin inhibitor BOP, can be combined with granulocyte colony-stimulating factor to promote hematopoietic stem cell mobilization. In addition, some potential mobilization targets, such as prostaglandin E2 receptor and sphingosine 1-phosphate, are still in the research stage. In addition to inherent patient characteristics and treatment options, incorporating biomarkers into the factors affecting mobilization and developing new predictive models will help to effectively predict the failure of hematopoietic stem cell mobilization and improve stem cell mobilization technology.