MiR-200b in heme oxygenase-1-modified bone marrow mesenchymal stem cell-derived exosomes alleviates inflammatory injury of intestinal epithelial cells by targeting high mobility group box 3

Exosomes derived from mesenchymal stem cells containing berberine for ulcerative colitis therapy

Berberine (Ber), an isoquinoline alkaloid, is a potential drug therapy for ulcerative colitis (UC) because of its anti-inflammatory activity, high biological safety, and few side effects. Nevertheless, its clinical application is hindered by its limited water solubility and low bioavailability. Currently, compared to synthetic nanocarriers, exosomes as carriers possess advantages such as low toxicity, high stability, and high specificity. Human placental mesenchymal stem cell-derived exosomes (HplMSC-Exos) have emerged as a promising drug delivery system, offering intrinsic anti-inflammatory and antioxidant activities. Therefore, we engineered MSC-Exos loaded with Ber (Exos-Ber) to enhance the solubility and bioavailability of Ber and for colon targeting, revealing a novel approach for treating UC with natural compounds. Structurally and functionally, Exos-Ber closely resembled unmodified Exos. Both in vitro and in vivo investigations confirmed the antioxidant and anti-inflammatory properties of Exos-Ber. Notably, Exos-Ber exhibited reparative effects on injured epithelial cells and reduced cellular apoptosis. Furthermore, Exos-Ber concurrently demonstrated anti-inflammatory and antioxidant activities, contributing to the mitigation of UC, possibly through its modulation of the MAPK signaling pathway. Overall, our findings demonstrate the potential of Exos-Ber as a promising therapeutic option for alleviating UC, highlighting its capacity to enhance the clinical applicability of Ber.

Exosomes derived from bone marrow mesenchymal stem cells alleviate biliary ischemia reperfusion injury in fatty liver transplantation by inhibiting ferroptosis

Fatty liver grafts are susceptible to ischemia reperfusion injury (IRI), increasing the risk of biliary complications after liver transplantation (LT). Ferroptosis, a newly recognized programmed cell death, is expected to be a novel therapeutic target for IRI. We investigated whether exosomes derived from heme oxygenase 1-modified bone marrow mesenchymal stem cells (HExos) relieve ferroptosis and protect biliary tracts from IRI in a rat fatty liver transplantation model. Rats were fed with a methionine choline deficient (MCD) diet for 2 weeks to induce severe hepatic steatosis. Steatotic grafts were implanted and HExos were administered after liver transplantation. A series of functional assays and pathological analysis were performed to assess ferroptosis and biliary IRI. The HExos attenuated IRI following liver transplantation, as demonstrated by less ferroptosis, improved liver function, less Kupffer and T cell activation, and less long-term biliary fibrosis. MicroRNA (miR)-204-5p delivered by HExos negatively regulated ferroptosis by targeting a key pro-ferroptosis enzyme, ACSL4. Ferroptosis contributes to biliary IRI in fatty liver transplantation. HExos protect steatotic grafts by inhibiting ferroptosis, and may become a promising strategy to prevent biliary IRI and expand the donor pool.

Macrophage-derived exosomal HMGB3 regulates silica-induced pulmonary inflammation by promoting M1 macrophage polarization and recruitment

BACKGROUND

Chronic inflammation and fibrosis are characteristics of silicosis, and the inflammatory mediators involved in silicosis have not been fully elucidated. Recently, macrophage-derived exosomes have been reported to be inflammatory modulators, but their role in silicosis has not been explored. The purpose of the present study was to investigate the role of macrophage-derived exosomal high mobility group box 3 (HMGB3) in silica-induced pulmonary inflammation.

METHODS

The induction of the inflammatory response and the recruitment of monocytes/macrophages were evaluated by immunofluorescence, flow cytometry and transwell assays. The expression of inflammatory cytokines was examined by RT-PCR and ELISA, and the signalling pathways involved were examined by western blot analysis.

RESULTS

HMGB3 expression was increased in exosomes derived from silica-exposed macrophages. Exosomal HMGB3 significantly upregulated the expression of inflammatory cytokines, activated the STAT3/MAPK (ERK1/2 and p38)/NF-κB pathways in monocytes/macrophages, and promoted the migration of these cells by CCR2.

CONCLUSIONS

Exosomal HMGB3 is a proinflammatory modulator of silica-induced inflammation that promotes the inflammatory response and recruitment of monocytes/macrophages by regulating the activation of the STAT3/MAPK/NF-κB/CCR2 pathways.

Mesenchymal stem cells and ferroptosis: Clinical opportunities and challenges

Objective

This review discusses recent experimental and clinical findings related to ferroptosis, with a focus on the role of MSCs. Therapeutic efficacy and current applications of MSC-based ferroptosis therapies are also discussed.

Background

Ferroptosis is a type of programmed cell death that differs from apoptosis, necrosis, and autophagy; it involves iron metabolism and is related to the pathogenesis of many diseases, such as Parkinson's disease, cancers, and liver diseases. In recent years, the use of mesenchymal stem cells (MSCs) and MSC-derived exosomes has become a trend in cell-free therapies. MSCs are a heterogeneous cell population isolated from a diverse range of human tissues that exhibit immunomodulatory functions, regulate cell growth, and repair damaged tissues. In addition, accumulating evidence indicates that MSC-derived exosomes play an important role, mainly by carrying a variety of bioactive substances that affect recipient cells. The potential mechanism by which MSC-derived exosomes mediate the effects of MSCs on ferroptosis has been previously demonstrated. This review provides the first overview of the current knowledge on ferroptosis, MSCs, and MSC-derived exosomes and highlights the potential application of MSCs exosomes in the treatment of ferroptotic conditions. It summarizes their mechanisms of action and techniques for enhancing MSC functionality. Results obtained from a large number of experimental studies revealed that both local and systemic administration of MSCs effectively suppressed ferroptosis in injured hepatocytes, neurons, cardiomyocytes, and nucleus pulposus cells and promoted the survival and regeneration of injured organs.

Methods

We reviewed the role of ferroptosis in related tissues and organs, focusing on its characteristics in different diseases. Additionally, the effects of MSCs and MSC-derived exosomes on ferroptosis-related pathways in various organs were reviewed, and the mechanism of action was elucidated. MSCs were shown to improve the disease course by regulating ferroptosis.

Ferroptosis: a promising candidate for exosome-mediated regulation in different diseases

Ferroptosis is a newly discovered form of cell death that is featured in a wide range of diseases. Exosome therapy is a promising therapeutic option that has attracted much attention due to its low immunogenicity, low toxicity, and ability to penetrate biological barriers. In addition, emerging evidence indicates that exosomes possess the ability to modulate the progression of diverse diseases by regulating ferroptosis in damaged cells. Hence, the mechanism by which cell-derived and noncellular-derived exosomes target ferroptosis in different diseases through the system Xc-/GSH/GPX4 axis, NAD(P)H/FSP1/CoQ10 axis, iron metabolism pathway and lipid metabolism pathway associated with ferroptosis, as well as its applications in liver disease, neurological diseases, lung injury, heart injury, cancer and other diseases, are summarized here. Additionally, the role of exosome-regulated ferroptosis as an emerging repair mechanism for damaged tissues and cells is also discussed, and this is expected to be a promising treatment direction for various diseases in the future. Video Abstract.

Secretome-based acellular therapy of bone marrow-derived mesenchymal stem cells in degenerative and immunological disorders: A narrative review

The bone marrow (BM) plays a pivotal role in homeostasis by supporting hematopoiesis and immune cells' activation, maturation, interaction, and deployment. "BMSC-derived secretome" refers to the complete repertoire of secreted molecules, including nucleic acids, chemokines, growth factors, cytokines, and lipids from BM-derived mesenchymal stem cells (BMSCs). BMSC-derived secretomes are the current molecular platform for acellular therapy. Secretomes are highly manipulable and can be synthesised in vast quantities using commercially accessible cell lines in the laboratory. Secretomes are less likely to elicit an immunological response because they contain fewer surface proteins. Moreover, the delivery of BMSC-derived secretomes has been shown in numerous studies to be an effective, cell-free therapy method for alleviating the symptoms of inflammatory and degenerative diseases. As a result, secretome delivery from BMSCs has the same therapeutic effects as BMSCs transplantation but may have fewer adverse effects. Additionally, BMSCs' secretome has therapeutic promise for organoids and parabiosis studies. This review focuses on recent advances in secretome-based cell-free therapy, including its manipulation, isolation, characterisation, and delivery systems. The diverse bioactive molecules of secretomes that successfully treat inflammatory and degenerative diseases of the musculoskeletal, cardiovascular, nervous, respiratory, reproductive, gastrointestinal, and anti-ageing systems were also examined in this review. However, secretome-based therapy has some unfavourable side effects that may restrict its uses. Some of the adverse effects of this modal therapy were briefly mentioned in this review.

CIRCULAR RNA CIRC_0099188 CONTRIBUTES TO LPS-INDUCED HPAEpiC CELL INJURY BY TARGETING THE MIR-1236-3P/HMGB3 AXIS

ABSTRACT

Purpose: This study is designed to explore the role and mechanism of circ_0099188 in LPS-engendered HPAEpiC cells. Methods: Circ_0099188, microRNA-1236-3p (miR-1236-3p), and high mobility group box 3 (HMGB3) levels were measured using real-time quantitative polymerase chain reaction. Cell viability and apoptosis were assessed using cell counting kit-8 (CCK-8) and flow cytometry assays. Protein levels of B-cell lymphoma-2 (Bcl-2), Bcl-2 related X protein (Bax), cleaved-caspase 3, cleaved-caspase 9, and HMGB3 were determined using Western blot assay. IL-6, IL-8, IL-1β, and TNF-α levels were analyzed using enzyme-linked immunosorbent assays. After predicting using Circinteractome and Targetscan, the binding between miR-1236-3p and circ_0099188 or HMGB3 was verified using a dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. Results: Circ_0099188 and HMGB3 were highly expressed, and miR-1236-3p was decreased in LPS-stimulated HPAEpiC cells. Also, the downregulation of circ_0099188 might overturn LPS-triggered HPAEpiC cell proliferation, apoptosis, and inflammatory response. Mechanically, circ_0099188 is able to affect HMGB3 expression by sponging miR-1236-3p. Conclusion: Circ_0099188 knockdown might mitigate LPS-induced HPAEpiC cell injury by targeting the miR-1236-3p/HMGB3 axis, providing an underlying therapeutic strategy for pneumonia treatment.

Mesenchymal Stem Cell-derived Exosomes: Novel Therapeutic Approach for Inflammatory Bowel Diseases

As double membrane-encapsulated nanovesicles (30-150 nm), exosomes (Exos) shuttle between different cells to mediate intercellular communication and transport active cargoes of paracrine factors. The anti-inflammatory and immunomodulatory activities of mesenchymal stem cell (MSC)-derived Exos (MSC-Exos) provide a rationale for novel cell-free therapies for inflammatory bowel disease (IBD). Growing evidence has shown that MSC-Exos can be a potential candidate for treating IBD. In the present review, we summarized the most critical advances in the properties of MSC-Exos, provided the research progress of MSC-Exos in treating IBD, and discussed the molecular mechanisms underlying these effects. Collectively, MSC-Exos had great potential for cell-free therapy in IBD. However, further studies are required to understand the full dimensions of the complex Exo system and how to optimize its effects.

Macrophage-derived exosomes regulate gastric cancer cell oxaliplatin resistance by wrapping circ 0008253

Oxaliplatin (OXA) is a first-line chemotherapy drug for gastric cancer. We aimed to investigate the effect of circ 0008253, contained in M2 polarized macrophage-derived exosomes, on OXA resistance of gastric carcinoma cells. Flow cytometry was performed to detect the differentiation of macrophages and cell apoptosis. Cell Counting Kit-8 assay was conducted to examine the cell viability. Transmission electron microscopy, Nanoparticle Tracking Analysis, Western bolt, and Immunofluorescence were carried out. Cell proliferation was detected with a colony formation experiment. Levels of CD206, Arg1, IL-10, and TGF-β were increased in M2 polarized macrophages. Cell viability was decreased gradually with the increase of time and OXA concentration. Apoptosis of gastric carcinoma cells was decreased after co-culture with M2-polarized macrophages. Exosomes isolated from M2-polarized macrophages (M2-Exos) could be co-located with gastric carcinoma cells. M2-Exos enhanced drug resistance, reduced apoptosis and OXA resistance. Bioinformatics analysis showed that circ 0008253 could be transferred from M2-Exos to gastric carcinoma cells. Overexpressing circ 0008253 increased cell viability, tumor size, and ABCG2 levels, decreased OXA sensitivity. Circ 0008253, contained in M2-Exos, was directly transferred from tumor-associated macrophage to gastric carcinoma cells, finally enhancing OXA resistance.

Alleviation of Spinal Cord Injury by MicroRNA 137-Overexpressing Bone Marrow Mesenchymal Stem Cell-Derived Exosomes

Bone marrow mesenchymal stem cell (BMMSC) is reported to promote spinal cord injury (SCI) recovery via secreting exosomes to deliver RNAs, proteins, lipids, etc. The present study aimed to investigate the effect of microRNA 137 (miR-137)-overexpressing BMMSC exosomes on SCI rats. BMMSCs were extracted from Sprague-Dawley (SD) rat hind leg bone marrow, and then BMMSC-secreted exosomes were collected. MiR-137 mimic and negative control (NC) mimic were transfected into BMMSCs, and then the corresponding exosomes were collected. Subsequently, SD rats were treated with sham operation + phosphate-buffered saline (PBS), SCI operation + PBS, SCI operation + NC mimic BMMSC exosomes, or SCI operation + miR-137-overexpressing BMMSC exosomes. MiR-137 was downregulated in the spinal cord tissue of SCI rats compared to sham rats. Furthermore, BMMSC exosome injection elevated the Basso, Beattie, and Bresnahan (BBB) scores and neuronal viability and reduced tissue injury and proinflammatory cytokine expression in the spinal cord tissue of SCI rats compared to PBS treatment. Subsequently, miR-137-overexpressing BMMSC exosome injection improved the BBB score and neuron viability, and decreased tissue injury as well as proinflammatory cytokine expression in SCI rats compared to NC-overexpressing BMMSC exosomes. Additionally, miR-137-overexpressing BMMSC exosomes also diminished neuronal apoptosis in the spinal cord tissue of SCI rats compared to NC-overexpressing BMMSC exosomes. In conclusion, miR-137-overexpressing BMMSC exosomes reduce tissue injury and inflammation while improving locomotor capacity and neuronal viability in SCI rats. These findings suggest that miR-137-overexpressing BMMSC exosomes may serve as a treatment option for SCI recovery.

Strategies to improve the effect of mesenchymal stem cell therapy on inflammatory bowel disease

Inflammatory bowel disease (IBD) includes Crohn’s disease and ulcerative colitis and is an idiopathic, chronic inflammatory disease of the colonic mucosa. The occurrence of IBD, causes irreversible damage to the colon and increases the risk of carcinoma. The routine clinical treatment of IBD includes drug treatment, endoscopic treatment and surgery. The vast majority of patients are treated with drugs and biological agents, but the complete cure of IBD is difficult. Mesenchymal stem cells (MSCs) have become a new type of cell therapy for the treatment of IBD due to their immunomodulatory and nutritional functions, which have been confirmed in many clinical trials. This review discusses some potential mechanisms of MSCs in the treatment of IBD, summarizes the experimental results, and provides new insights to enhance the therapeutic effects of MSCs in future applications.

Tailored Extracellular Vesicles: Novel Tool for Tissue Regeneration

Extracellular vesicles (EVs) play an essential part in multiple pathophysiological processes including tissue injury and regeneration because of their inherent characteristics of small size, low immunogenicity and toxicity, and capability of carrying a variety of bioactive molecules and mediating intercellular communication. Nevertheless, accumulating studies have shown that the application of EVs faces many challenges such as insufficient therapeutic efficacy, a lack of targeting capability, low yield, and rapid clearance from the body. It is known that EVs can be engineered, modified, and designed to encapsulate therapeutic cargos like proteins, peptides, nucleic acids, and drugs to improve their therapeutic efficacy. Targeted peptides, antibodies, aptamers, magnetic nanoparticles, and proteins are introduced to modify various cell-derived EVs for increasing targeting ability. In addition, extracellular vesicle mimetics (EMs) and self-assembly EV-mimicking nanocomplex are applied to improve production and simplify EV purification process. The combination of EVs with biomaterials like hydrogel, and scaffolds dressing endows EVs with long-term therapeutic efficacy and synergistically enhanced regenerative outcome. Thus, we will summarize recent developments of EV modification strategies for more extraordinary regenerative effect in various tissue injury repair. Subsequently, opportunities and challenges of promoting the clinical application of engineered EVs will be discussed.

The Extracellular MicroRNAs on Inflammation: A Literature Review of Rodent Studies

Inflammation is an indispensable biological process stimulated by infection and injuries. Inflammatory mechanisms related to extracellular vesicles (EVs), which are small membrane structures carrying various molecules, were summarized in this review. Emerging evidence from animal studies has highlighted the role of EVs in modulating inflammatory responses, by transporting various molecules involved in host defense. In this review, we have discussed the role of EV miRNAs in inflammation. Rodent studies associated with extracellular miRNAs in inflammatory diseases, published from 2012 to 2022, were explored from PUBMED, EMBASE, and MEDLINE. A total of 95 studies were reviewed. In summary, EV-associated miRNAs play a key role in various diseases, including organ injury, immune dysfunction, neurological disease, metabolic syndrome, vesicular disease, arthritis, cancer, and other inflammatory diseases. Diverse EV-associated miRNAs regulate inflammasome activation and pro- and anti-inflammatory cytokine levels by targeting genes.

Intestinal Microbiota Participates in the Protective Effect of HO-1/BMMSCs on Liver Transplantation With Steatotic Liver Grafts in Rats

The present study aimed to explore whether heme oxygenase-1 (HO-1)-modified bone marrow mesenchymal stem cells (BMMSCs) have a protective effect on liver transplantation with steatotic liver grafts in rats, and to determine the role of the intestinal microbiota in such protection. HO-1/BMMSCs were obtained by transduction of Hmox1 gene [encoding heme oxygenase (HO-1)]-encoding adenoviruses into primary rat BMMSCs. Steatotic livers were obtained by feeding rats a high-fat diet, and a model of liver transplantation with steatotic liver grafts was established. The recipients were treated with BMMSCs, HO-1/BMMSCs, or neither, via the portal vein. Two time points were used: postoperative day 1 (POD 1) and POD 7. The results showed that under the effect of HO-1/BMMSCs, the degree of steatosis in the liver grafts was significantly reduced, and the level of liver enzymes and the levels of pro-inflammatory cytokines in plasma were reduced. The effect of HO-1/BMMSCs was better than that of pure BMMSCs in the prolongation of the rats' postoperative time. In addition, HO-1/BMMSCs promoted the recovery of recipients' intestinal structure and function, especially on POD 7. The intestinal villi returned to normal, the expression of tight junction proteins was restored, and intestinal permeability was reduced on POD 7. The intestinal bacterial of the LT group showed significantly weakened energy metabolism and overgrowth. On POD 1, the abundance of Akkermansiaceae was higher. On POD 7, the abundance of Clostridiaceae increased, the level of lipopolysaccharide increased, the intestinal mucosal barrier function was destroyed, and the levels of several invasive bacteria increased. When treated with HO-1/BMMSCs, the energy metabolism of intestinal bacteria was enhanced, and on POD 1, levels bacteria that protect the intestinal mucosa, such as Desulfovibrionaceae, increased significantly. On POD 7, the changed intestinal microbiota improved lipid metabolism and increased the levels of butyrate-producing bacteria, such as Lachnospiraceae. In conclusion, HO-1/BMMSCs have protective effects on steatotic liver grafts and the intestinal barrier function of the recipients. By improving lipid metabolism and increasing the abundance of butyrate-producing bacteria, the changed intestinal microbiota has a protective effect and prolongs the recipients' survival time.

miR-29a-3p in Exosomes from Heme Oxygenase-1 Modified Bone Marrow Mesenchymal Stem Cells Alleviates Steatotic Liver Ischemia-Reperfusion Injury in Rats by Suppressing Ferroptosis via Iron Responsive Element Binding Protein 2

Hepatic ischemia-reperfusion injury (IRI) is an inevitable result of liver surgery. Steatotic livers are extremely sensitive to IRI and have worse tolerance. Ferroptosis is considered to be one of the main factors of organ IRI. This study is aimed at exploring the role of ferroptosis in the effect of heme oxygenase-1-modified bone marrow mesenchymal stem cells (HO-1/BMMSCs) on steatotic liver IRI and its mechanism. An IRI model of a steatotic liver and a hypoxia reoxygenation (HR) model of steatotic hepatocytes (SHPs) were established. Rat BMMSCs were extracted and transfected with the Ho1 gene to establish HO-1/BMMSCs, and their exosomes were extracted by ultracentrifugation. Ireb2 was knocked down to verify its role in ferroptosis and cell injury in SHP-HR. Public database screening combined with quantitative real-time reverse transcription PCR identified microRNAs (miRNAs) targeting Ireb2 in HO-1/BMMSCs exosomes. miR-29a-3p mimic and inhibitor were used for functional verification experiments. Liver function, histopathology, terminal deoxynulceotidyl transferase nick-end-labeling staining, cell viability, mitochondrial membrane potential, and cell death were measured to evaluate liver tissue and hepatocyte injury. Ferroptosis was assessed by detecting the levels of IREB2, Fe²⁺, malondialdehyde, glutathione, lipid reactive oxygen species, glutathione peroxidase 4, prostaglandin-endoperoxide synthase 2 mRNA, and mitochondrial morphology. The results revealed that HO-1/BMMSCs improved liver tissue and hepatocyte injury and suppressed ferroptosis in vivo and in vitro. The expression of IREB2 was increased in steatotic liver IRI and SHP-HR. Knocking down Ireb2 reduced the level of Fe²⁺ and inhibited ferroptosis. HO-1/BMMSC exosomes reduced the expression of IREB2 and inhibited ferroptosis and cell damage. Furthermore, we confirmed high levels of miR-29a-3p in HO-1/BMMSCs exosomes. Overexpression of miR-29a-3p downregulated the expression of Ireb2 and inhibited ferroptosis. Downregulation of miR-29a-3p blocked the protective effect of HO-1/BMMSC exosomes on SHP-HR cell injury. In conclusion, ferroptosis plays an important role in HO-1/BMMSC-mediated alleviation of steatotic liver IRI. HO-1/BMMSCs could suppress ferroptosis by targeting Ireb2 via the exosomal transfer of miR-29a-3p.

Bone marrow mesenchymal stem cells-derived exosomes containing miR-539-5p inhibit pyroptosis through NLRP3/caspase-1 signalling to alleviate inflammatory bowel disease

BACKGROUND

Exosomes derived from bone mesenchymal stem cells (BMSCs) are potential candidates for inflammatory bowel disease (IBD) treatment. The present study investigated the therapeutic effect and potential mechanism of BMSCs-derived exosomes on pyroptosis in IBD.

METHODS

We induced IBD in mice and cell models through dextran sulfate sodium (DSS) and LPS, respectively. The mRNA and protein expression levels were assessed by qRT-PCR, Western blotting, IF and IHC. The concentrations of IL-1β, IL-18 and TNFα were assessed using ELISA. ROS levels were determined using DCFH-DA staining. Cell proliferation of mIECs was analysed using an MTT assay. In addition, a flow cytometry assay was performed to detect pyroptosis. Finally, the binding relationship between miR-539-5p and NLRP3 was verified by a dual luciferase reporter gene assay.

RESULTS

Our results revealed that intraperitoneal injection of BMSCs-derived exosomes inhibited DSS-induced pyroptosis as well as IBD symptoms in mice. In addition, BMSCs-derived exosome treatment suppressed pyroptosis, ROS levels and the concentrations of proinflammatory cytokines (IL-1β, IL-18 and TNFα) in LPS-treated mIECs in a miR-539-5p-dependent manner. Further research found that miR-539-5p suppressed NLRP3 expression in mIECs by directly targeting NLRP3. As expected, pyroptosis in LPS-treated mIECs was significantly reduced by NLRP3 knockdown. In addition, NLRP3 silencing restored the inhibitory effect of exosomes derived from BMSCs transfected with miR-539-5p inhibitor on pyroptosis in LPS-treated mIECs.

CONCLUSION

The present study demonstrated that BMSCs-derived exosomal miR-539-5p suppresses pyroptosis through NLRP3/caspase-1 signalling to inhibit IBD progression.

Intestinal epithelial cell-derived exosomes package microRNA-23a-3p alleviate gut damage after ischemia/reperfusion via targeting MAP4K4

Intestinal epithelial cells (IECs) contribute to regulation of gut injury after intestinal ischemia/reperfusion (II/R). Exosomes are well documented to deliver bioactive molecules to recipient cells for the purpose of modulating cell function. However, the role of IEC-derived exosomes in gut damage after II/R and the underlying mechanisms remain unclear. Here, we investigated the effects of exosomal miR-23a-3p on gut damage using primary IECs that underwent oxygen-glucose deprivation (OGD) as well as II/R rats. We observed that exosomes released by IECs attenuated damage in IECs that underwent OGD in vitro (P < 0.05) as well as the degree of gut injury after an II/R assault in vivo (P < 0.05). Injection of miR-23a-3p knockdown exosomes aggravated the II/R injury, whereas PF-6260933, a small-molecule inhibitor of MAP4K4, partly reversed the injury. Underlying mechanistic studies revealed that exosomal miR-23a-3p attenuated gut damage by regulating its downstream target, MAP4K4.

miR-124-3p delivered by exosomes from heme oxygenase-1 modified bone marrow mesenchymal stem cells inhibits ferroptosis to attenuate ischemia-reperfusion injury in steatotic grafts

Background

Steatotic livers tolerate ischemia–reperfusion injury (IRI) poorly, increasing the risk of organ dysfunction. Ferroptosis is considered the initiating factor of organ IRI. Heme oxygenase oxygen-1 (HO-1)-modified bone marrow mesenchymal stem cells (BMMSCs) (HO-1/BMMSCs) can reduce hepatic IRI; however, the role of ferroptosis in IRI of steatotic grafts and the effect of HO-1/BMMSCs-derived exosomes (HM-exos) on ferroptosis remain unknown.

Methods

A model of rat liver transplantation (LT) with a severe steatotic donor liver and a model of hypoxia and reoxygenation (H/R) of steatotic hepatocytes were established. Exosomes were obtained by differential centrifugation, and the differentially expressed genes (DEGs) in liver after HM-exo treatment were detected using RNA sequencing. The expression of ferroptosis markers was analyzed. microRNA (miRNA) sequencing was used to analyze the miRNA profiles in HM-exos.

Results

We verified the effect of a candidate miRNA on ferroptosis of H/R treated hepatocytes, and observed the effect of exosomes knockout of the candidate miRNA on hepatocytes ferroptosis. In vitro, HM-exo treatment reduced the IRI in steatotic grafts, and enrichment analysis of DEGs suggested that HM-exos were involved in the regulation of the ferroptosis pathway. In vitro, inhibition of ferroptosis by HM-exos reduced hepatocyte injury. HM-exos contained more abundant miR-124-3p, which reduced ferroptosis of H/R-treated cells by inhibiting prostate six transmembrane epithelial antigen 3 (STEAP3), while overexpression of Steap3 reversed the effect of mir-124-3p. In addition, HM-exos from cell knocked out for miR-124-3p showed a weakened inhibitory effect on ferroptosis. Similarly, HM-exo treatment increased the content of miR-124-3p in grafts, while decreasing the level of STEAP3 and reducing the degree of hepatic ferroptosis.

Conclusion

Ferroptosis is involved in the IRI during LT with a severe steatotic donor liver. miR-124-3p in HM-exos downregulates Steap3 expression to inhibit ferroptosis, thereby attenuating graft IRI, which might be a promising strategy to treat IRI in steatotic grafts.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01407-8.

microRNA-265 Regulates Bone Marrow Mesenchymal Stem Cells Differentiation and Promotes Sepsis Lung Injury Repair via Transforming Growth Factor Beta 1

Our study investigates whether miR-265 regulates the differentiation of rat bone marrow mesenchymal stem cells (BMSCs) into alveolar type II epithelial cells (ATII) through TGF-β1 and promotes lung injury repair in rats with sepsis, thereby inhibiting sepsis progression. 25 patients with sepsis admitted to the Respiratory and Critical Care Medicine Department of the hospital and 17 normal controls were included. TGF-β1 level was measured by ELISA. miR-265 level was measured by qRT-PCR and AT II-related genes and proteins expression was analyzed by western blot and qRT-PCR. miR-265 expression was significantly higher in sepsis patients than normal group. Progenitor BMSCs were long and shuttle-shaped after 1 and 3 days of growth. Cultured MSCs had low expression of the negative antigen CD34 (4.32%) and high expression of the positive antigen CD44 (99.87%). TGF-β1 level was significantly increased with longer induction time, while miR-265 expression was significantly decreased in cell culture medium. miR-265 interference significantly decreased TGF-β1 expression. In conclusion, miR-265 inhibits BMSC differentiation to AT II via regulation of TGF-β1, thereby inhibiting sepsis progression.

HO-1/BMMSC perfusion using a normothermic machine perfusion system reduces the acute rejection of DCD liver transplantation by regulating NKT cell co-inhibitory receptors in rats

Background

Liver transplantation (LT) is required in many end-stage liver diseases. Donation after cardiac death (DCD) livers are often used, and treatment of acute rejection (ACR) requires the use of immunosuppressive drugs that are associated with complications. Bone marrow mesenchymal stem cells (BMMSCs) are used in treatment following LT; however, they have limitations, including low colonization in the liver. An optimized BMMSC application method is required to suppress ACR.

Methods

BMMSCs were isolated and modified with the heme oxygenase 1 (HO-1) gene. HO-1/BMMSCs were perfused into donor liver in vitro using a normothermic machine perfusion (NMP) system, followed by LT into rats. The severity of ACR was evaluated based on liver histopathology. Gene chip technology was used to detect differential gene expression, and flow cytometry to analyze changes in natural killer (NK) T cells.

Results

NMP induced BMMSCs to colonize the donor liver during in vitro preservation. The survival of HO-1/BMMSCs in liver grafts was significantly longer than that of unmodified BMMSCs. When the donor liver contained HO-1/BMMSCs, the local immunosuppressive effect was improved and prolonged, ACR was controlled, and survival time was significantly prolonged. The application of HO-1/BMMSCs reduced the number of NKT cells in liver grafts, increased the expression of NKT cell co-inhibitory receptors, and reduced NKT cell expression of interferon-γ.

Conclusions

NK cell and CD8⁺ T cell activation was inhibited by application of HO-1/BMMSCs, which reduced ACR of transplanted liver. This approach could be developed to enhance the success rate of LT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02647-5.

Mechanism and Potential of Extracellular Vesicles Derived From Mesenchymal Stem Cells for the Treatment of Infectious Diseases

Extracellular vesicles (EVs) are nano-sized membrane vesicles secreted by cells. EVs serve as a mediator for cell-to-cell communication by regulating the exchange of genetic materials and proteins between the donor and surrounding cells. Current studies have explored the therapeutic value of mesenchymal stem cells-derived EVs (MSC-EVs) for the treatment of infectious diseases extensively. MSC-EVs can eliminate the pathogen, regulate immunity, and repair tissue injury in contagious diseases through the secretion of antimicrobial factors, inhibiting the replication of pathogens and activating the phagocytic function of macrophages. MSC-EVs can also repair tissue damage associated with the infection by upregulating the levels of anti-inflammatory factors, downregulating the pro-inflammatory factors, and participating in the regulation of cellular biological behaviors. The purpose of this mini-review is to discuss in detail the various mechanisms of MSC-EV treatment for infectious diseases including respiratory infections, sepsis, and intestinal infections, as well as challenges for implementing MSC-EVs from bench to bedside.

Therapeutic Potential of Mesenchymal Stromal Cell-Derived Extracellular Vesicles in the Prevention of Organ Injuries Induced by Traumatic Hemorrhagic Shock

Severe trauma is the principal cause of death among young people worldwide. Hemorrhagic shock is the leading cause of death after severe trauma. Traumatic hemorrhagic shock (THS) is a complex phenomenon associating an absolute hypovolemia secondary to a sudden and significant extravascular blood loss, tissue injury, and, eventually, hypoxemia. These phenomena are responsible of secondary injuries such as coagulopathy, endotheliopathy, microcirculation failure, inflammation, and immune activation. Collectively, these dysfunctions lead to secondary organ failures and multi-organ failure (MOF). The development of MOF after severe trauma is one of the leading causes of morbidity and mortality, where immunological dysfunction plays a central role. Damage-associated molecular patterns induce an early and exaggerated activation of innate immunity and a suppression of adaptive immunity. Severe complications are associated with a prolonged and dysregulated immune–inflammatory state. The current challenge in the management of THS patients is preventing organ injury, which currently has no etiological treatment available. Modulating the immune response is a potential therapeutic strategy for preventing the complications of THS. Mesenchymal stromal cells (MSCs) are multipotent cells found in a large number of adult tissues and used in clinical practice as therapeutic agents for immunomodulation and tissue repair. There is growing evidence that their efficiency is mainly attributed to the secretion of a wide range of bioactive molecules and extracellular vesicles (EVs). Indeed, different experimental studies revealed that MSC-derived EVs (MSC-EVs) could modulate local and systemic deleterious immune response. Therefore, these new cell-free therapeutic products, easily stored and available immediately, represent a tremendous opportunity in the emergency context of shock. In this review, the pathophysiological environment of THS and, in particular, the crosstalk between the immune system and organ function are described. The potential therapeutic benefits of MSCs or their EVs in treating THS are discussed based on the current knowledge. Understanding the key mechanisms of immune deregulation leading to organ damage is a crucial element in order to optimize the preparation of EVs and potentiate their therapeutic effect.

Exosomes as a New Delivery Vehicle in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a type of chronic relapsing inflammatory disease. The pathogenesis of IBD is still unclear, which may involve environmental factors, genetic factors, intestinal microbiota disorder, and abnormal immune responses. Exosomes (30–150 nm) are found in various body fluids, including blood, saliva, urine, and cerebrospinal fluid. Exosomes mediate intercellular communication and regulate cell biological activity by carrying non-coding RNAs, proteins, and lipids. There is evidence that exosomes are involved in the pathogenesis of IBD. In view of the important roles of exosomes in the pathogenesis of IBD, this work systematically reviews the latest research progress of exosomes in IBD, especially the roles of exosomes as non-coding RNA delivery systems in the pathogenesis of IBD, including a disordered immune response, barrier function, and intestinal microbiota. The review will help to clarify the pathogenesis of IBD and explore new diagnostic markers and therapeutic targets for patients with IBD.

Bone Marrow Mesenchymal Stem Cell (BMSC)-Derived Exosomes Increase Colon Cancer Cell Apoptosis and Inhibit Proliferation and Migration

This study aims to investigate whether bone marrow mesenchymal stem cell (BMSC) exosomes (BMSC-exos) affects the progression of colon cancer. Ultracentrifugation was used to extract and collect BMSC-exos which were assessed under electron microscope and by flow cytometry. The BMSCs were divided into two groups: control group treated with α-MEM basal medium and experimental group with exosomes (10 μg/ml). Exos were extracted from BMSCs and co-cultured with colon cancer cells, followed by analysis of cell viability by CCK-8 assay and GLUT3 mRNA and protein expression by RT-qPCR and Western blot. The electron microscope analysis indicated that the primary BMSCs showed a long spindle shape with a negative expression of antigen CD34 and positive antigen CD90. Importantly, exos inhibited the viability of colon cancer cells HCT116 and decreased the expression of GLUT3, suggesting that exos might increase the colon cancer cell apoptosis. In conclusion, BMSC-exos inhibit cell progression in colon cancer and might be served as a promising biomarker.

Spatial variation in gene expression of Tasmanian devil facial tumors despite minimal host transcriptomic response to infection

BACKGROUND

Transmissible cancers lie at the intersection of oncology and infectious disease, two traditionally divergent fields for which gene expression studies are particularly useful for identifying the molecular basis of phenotypic variation. In oncology, transcriptomics studies, which characterize the expression of thousands of genes, have identified processes leading to heterogeneity in cancer phenotypes and individual prognoses. More generally, transcriptomics studies of infectious diseases characterize interactions between host, pathogen, and environment to better predict population-level outcomes. Tasmanian devils have been impacted dramatically by a transmissible cancer (devil facial tumor disease; DFTD) that has led to widespread population declines. Despite initial predictions of extinction, populations have persisted at low levels, due in part to heterogeneity in host responses, particularly between sexes. However, the processes underlying this variation remain unknown.

RESULTS

We sequenced transcriptomes from healthy and DFTD-infected devils, as well as DFTD tumors, to characterize host responses to DFTD infection, identify differing host-tumor molecular interactions between sexes, and investigate the extent to which tumor gene expression varies among host populations. We found minimal variation in gene expression of devil lip tissues, either with respect to DFTD infection status or sex. However, 4088 genes were differentially expressed in tumors among our sampling localities. Pathways that were up- or downregulated in DFTD tumors relative to normal tissues exhibited the same patterns of expression with greater intensity in tumors from localities that experienced DFTD for longer. No mRNA sequence variants were associated with expression variation.

CONCLUSIONS

Expression variation among localities may reflect morphological differences in tumors that alter ratios of normal-to-tumor cells within biopsies. Phenotypic variation in tumors may arise from environmental variation or differences in host immune response that were undetectable in lip biopsies, potentially reflecting variation in host-tumor coevolutionary relationships among sites that differ in the time since DFTD arrival.

Heme Oxygenase-1-Modified Bone Marrow Mesenchymal Stem Cells Combined with Normothermic Machine Perfusion Repairs Bile Duct Injury in a Rat Model of DCD Liver Transplantation via Activation of Peribiliary Glands through the Wnt Pathway

Livers from donors after circulatory death (DCD) are inevitably exposed to a longer warm ischemic period, which might increase the incidence of postoperative bile duct complications. Bone marrow mesenchymal stem cells (BMMSCs) have tissue repair properties. The present study was aimed at exploring the repair effect of heme oxygenase-1- (HO-1-) modified BMMSCs (HO-1/BMMSCs) combined with normothermic machine perfusion (NMP) on bile duct injury after DCD liver transplantation and at revealing the underlying mechanisms. Rat livers were exposed to in situ warm ischemia for 30 min; then, NMP was performed through the portal vein for 4 h with BMMSCs, HO-1/BMMSCs, or neither before implantation. Obvious bile duct histological damage and liver functional damage were observed postoperatively. In the group treated with HO-1/BMMSCs combined with NMP (HBP group), liver functions and bile duct histology were improved; meanwhile, cell apoptosis was reduced and cell proliferation was active. A large number of regenerative cells appeared at the injured site, and the defective bile duct epithelium was restored. Dilatation of peribiliary glands (PBGs), proliferation of PBG cells, high expression of vascular endothelial growth factor (VEGF), and increased proportion of bile duct progenitor cells with stem/progenitor cells biomarkers were observed. Blocking Wnt signaling significantly inhibited the repair effect of HO-1/BMMSCs on bile duct injury. In conclusion, HO-1/BMMSCs combined with NMP were relevant to the activation of biliary progenitor cells in PBGs which repaired bile duct injury in DCD liver transplantation via the Wnt signaling pathway. Proliferation and differentiation of PBG cells were involved in the renewal of the injured biliary epithelium.

The role of high mobility group protein B3 (HMGB3) in tumor proliferation and drug resistance

The high mobility group protein B (HMGB) family (including HMGB1, HMGB2, HMGB3, and HMGB4) can regulate the mechanisms of DNA replication, transcription, recombination, and repair, and act as cytokines to mediate responses to infection, injury, and inflammation. HMGB1/2/3 has a high similarity in sequence and structure, while HMGB4 has no acidic C-terminal tail. Among them, HMGB3 can regulate the self-renewal and differentiation of normal hematopoietic stem cell population, but the decrease of its expression is easy to induce leukemia. Up-regulation of its expression promotes tumor development and chemotherapy resistance through a variety of mechanisms, and non-coding RNA can regulate to promote tumor cell proliferation, invasion, and migration and inhibit cancer cell apoptosis.

The emerging role of exosomes in the pathogenesis, prognosis and treatment of necrotizing enterocolitis

Exosomes are a subtype of extracellular vesicles. They contain bioactive molecules, including nucleic acids, proteins and lipids. Among the currently described exosomes, a majority are potential candidates for the diagnosis and treatment of necrotizing enterocolitis (NEC). In this work, we reviewed existing literature reports on exosomes and explored their roles in NEC. Exosomes derived from intestinal epithelial cells (IECs) participates in the development of intestinal diseases, thus can potentially be utilized as biomarkers for NEC. Besides, exosomes of human milk have been demonstrated to protect IECs from oxidative stress, stimulate intestinal stem cells activity, improve the proliferation and migration of IECs, and lower the incidence and severity of experimental NEC. Further, exosomes produced by stem cells can reduce the severity of experimental NEC and protect the intestinal barrier function during NEC. Conclusively, exosomes have been shown to influence the pathogenesis of NEC and exert a protective effect on NEC. However, additional investigations would be urgently necessary to comprehensively elucidate the underlying mechanisms of exosomes in NEC.