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.

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.

Remyelination in the central nervous system is a basic repair process triggered by demyelinating events, mainly through the proliferation, migration, and differentiation of oligodendrocyte precursor cells into oligodendrocytes. The process of remyelination is affected by many factors such as astrocytes, myelin debris, microglia, macrophages, endothelial cells, pericytes, T cells, and age.

Astrocytes play an important role in regulating synaptic activity, nutritional support, and tissue repair in the central nervous system. This review aims to provide potential therapeutic targets for demyelinating diseases of central nervous system by reviewing the role of astrocytes in remyelination.

A search was conducted on relevant literature collected from CNKI, PubMed, and Web of Science from 2014 to 2024. The search terms were “astrocytes, oligodendrocyte precursor cells, remyelination” in both Chinese and English. Finally, 66 articles were included after screening and summarized.

(1) The treatment of demyelinating diseases, such as multiple sclerosis, is limited to disease-modifying therapies, and there is no available method to overcome the failure of remyelination. Therefore, it is necessary to explore targets related to remyelination to promote myelin repair. (2) Remyelination is a process in which oligodendrocyte precursor cells proliferate, migrate, differentiate, and mature into oligodendrocytes, and the latter produce myelin to wrap axons to form myelin sheath. (3) Astrocytes regulate remyelination by phagocytosis of myelin debris, participating in inflammatory response, transforming into oligodendrocyte lineage cells, providing energy supply for oligodendrocyte lineage cells, releasing neurotrophic factors, and secreting extracellular matrix components. (4) The drugs screened in this paper use astrocytes and their derived factors as intervention targets to regulate the remyelination. Some drugs have satisfactory effects, but their effectiveness and safety still need more basic research and clinical trials to verify. (5) The mechanism of action of astrocytes in remyelination has not been fully elucidated, and the related molecular targets and signaling pathways can be further studied.

Bone marrow mesenchymal stem cells are the main effector cells for bone formation. With the increase of age, the regenerative ability of bone marrow mesenchymal stem cells is weakened and the differentiation function is impaired, leading to poor osteoporosis. Therefore, restoring the regenerative capacity and cellular function of aged bone marrow mesenchymal stem cells is essential for the effective treatment of osteoporosis.

To investigate the effects of passage 3 and passage 11 bone marrow mesenchymal stem cells-derived exosomes of young rats on the aging of bone marrow mesenchymal stem cells derived from elderly rats.

Bone marrow mesenchymal stem cells from 6-8-week-old female SD rats were isolated and cultured, and passaged to the passages 3 and 11, respectively. Then, exosomes from passages 3 and 11 bone marrow mesenchymal stem cells were extracted. Bone marrow mesenchymal stem cells from 18-month-old female SD rats were isolated and cultured, passaged to passage 3, and divided into 3 groups. The control group was routinely cultured, and the other two groups were intervened with exosomes from passages 3 and 11 bone marrow mesenchymal stem cells. After 48 hours of exosome intervention, the expression of β-galactosidase in the nucleus was detected by β-galactosidase staining kit. The expression of aging-related genes was detected by qRT-PCR. The expression differences of miRNA in exosomes from passages 3 and 11 bone marrow mesenchymal stem cells were compared by Small RNA sequencing.

(1) Compared with the control group and passage 11 bone marrow mesenchymal stem cell-derived exosomes group, the β-galactosidase activity of bone marrow mesenchymal stem cells of aged rats was significantly lower in the passage 3 bone marrow mesenchymal stem cell-derived exosomes group. (2) Compared with the control group, the expression of aging-related genes p21 and p16 was significantly reduced in the passage 3 bone marrow mesenchymal stem cell-derived exosome group (P < 0.05), while there was no significant difference in the expression of aging-related genes p21 and p16 in the passage 11 bone marrow mesenchymal stem cell-derived exosome group. (3) Sequencing results showed that there was a significant difference in the expression of miRNAs in the two exosomes, among which the miRNAs with the most significant expression differences were let-7c-5p, let-7b-5p, miR-320-3p, and miR-26a-5p. KEGG analysis results showed that significantly different miRNA enrichment pathways include mTOR, AMPK and other aging-related signaling pathways. The above results indicate that passage 3 bone marrow mesenchymal stem cell-derived exosomes have the ability to reverse the aging of bone marrow mesenchymal stem cells in aged rats.

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.

Autologous or artificial bone grafts have been widely used to repair maxillofacial bone defects clinically, but these methods still suffer from insufficient osteogenesis. Bone marrow mesenchymal stem cells play a key role in the bone formation. Notably, ectoderm-derived jaw bone marrow mesenchymal stem cells have stronger proliferation and osteogenic differentiation capacity compared with mesoderm-derived iliac bone marrow mesenchymal stem cells, elucidating the key mechanisms involved. It is expected to provide a new strategy for the repair of craniomaxillofacial bone defects.

To compare the biological differences between human jaw bone marrow mesenchymal stem cells and iliac bone marrow mesenchymal stem cells and identify the key regulatory genes.

(1) Jaw bone and iliac bone were collected from three patients with alveolar cleft. Primary bone marrow mesenchymal stem cells were isolated and cultured. Cell proliferation ability was detected by colony formation assay. Cell senescence was detected by β-galactosidase staining assay. Senescence and osteogenesis-related protein expression levels were detected by western blot assay. Osteogenic ability was detected by alizarin red staining after osteogenic induction solution treatment. (2) Jaw bone marrow mesenchymal stem cells and iliac bone marrow mesenchymal stem cells were subjected to transcriptome and differential gene expression analysis to find the 20 genes with the largest differential expression and identify the key regulatory factors. (3) The gene in iliac bone marrow mesenchymal stem cells were knocked down to comparatively analyze the changes in self-renewal, anti-aging and osteogenic capacity of iliac bone marrow mesenchymal stem cells. (4) The gene-edited iliac bone marrow mesenchymal stem cells were loaded into β-tricalcium phosphate scaffolds and implant into nude mice for 8 weeks. The scaffolds were stained with Masson staining and immunofluorescence staining to observe the difference in osteogenic capacity.

(1) Jaw bone marrow mesenchymal stem cells have stronger proliferation, anti-aging and osteogenic differentiation abilities compared to iliac bone marrow mesenchymal stem cells. (2) By transcriptome analysis, we identified HOXA10 as a highly up-regulated core transcription factor in iliac bone marrow mesenchymal stem cells. (3) After knocking down HOXA10 in iliac bone marrow mesenchymal stem cells, we observed a significant increase in proliferation, anti-aging, and osteogenic differentiation abilities. (4) After HOXA10 knocked-down iliac bone marrow mesenchymal stem cells/β-tricalcium phosphate was implanted subcutaneously on the back of nude mice, and their bone formation ability was stronger. (5) The above results suggest that HOXA10 is a key regulatory gene that determines the proliferative, anti-aging and osteogenic differentiation abilities of bone marrow mesenchymal stem cells. HOXA10 gene-modified iliac bone marrow mesenchymal stem cell transplantation can be used as a potential application strategy for repairing maxillofacial bone defects.

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.

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, the treatment methods for colorectal cancer include surgical resection and chemotherapy. However, the subsequent quality of life of patients cannot be improved due to the multiple surgical complications and drug resistance in the later stage of chemotherapy.

To review the mechanism of action, latest progress and existing problems of exosomes derived from mesenchymal stem cells in the treatment of colorectal cancer.

PubMed, CNKI and WanFang databases were searched for relevant literature using the search terms of “mesenchymal stem cells exosomes, colorectal cancer, chemotherapy, treatment” in Chinese and English, respectively. Finally, 96 articles were included for analysis.

(1) Mesenchymal stem cell-derived exosomes play different roles in the treatment of colorectal cancer mainly through the microRNAs and long-chain non-coding RNAs carried by themselves to mediate different signaling pathways. (2) Mesenchymal stem cell-derived exosomes are highly stable and biocompatible, which makes them excellent carriers of therapeutic drugs. (3) Mesenchymal stem cell-derived exosomes have different effects on resistance to different types of chemotherapeutic agents.

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.