Extracellular vesicles containing miR-146a attenuate experimental colitis by targeting TRAF6 and IRAK1

The role of mesenchymal stem cells in attenuating inflammatory bowel disease through ubiquitination

Inflammatory bowel disease (IBD), a condition of the digestive tract and one of the autoimmune diseases, is becoming a disease of significant global public health concern and substantial clinical burden. Various signaling pathways have been documented to modulate IBD, but the exact activation and regulatory mechanisms have not been fully clarified; thus, a need for constant exploration of the molecules and pathways that play key roles in the development of IBD. In recent years, several protein post-translational modification pathways, such as ubiquitination, phosphorylation, methylation, acetylation, and glycolysis, have been implicated in IBD. An aberrant ubiquitination in IBD is often associated with dysregulated immune responses and inflammation. Mesenchymal stem cells (MSCs) play a crucial role in regulating ubiquitination modifications through the ubiquitin-proteasome system, a cellular machinery responsible for protein degradation. Specifically, MSCs have been shown to influence the ubiquitination of key signaling molecules involved in inflammatory pathways. This paper reviews the recent research progress in MSC-regulated ubiquitination in IBD, highlighting their therapeutic potential in treating IBD and offering a promising avenue for developing targeted interventions to modulate the immune system and alleviate inflammatory conditions.

Exosome nanovesicles: biomarkers and new strategies for treatment of human diseases

Exosomes are nanoscale vesicles of cellular origin. One of the main characteristics of exosomes is their ability to carry a wide range of biomolecules from their parental cells, which are important mediators of intercellular communication and play an important role in physiological and pathological processes. Exosomes have the advantages of biocompatibility, low immunogenicity, and wide biodistribution. As researchers' understanding of exosomes has increased, various strategies have been proposed for their use in diagnosing and treating diseases. Here, we provide an overview of the biogenesis and composition of exosomes, describe the relationship between exosomes and disease progression, and focus on the use of exosomes as biomarkers for early screening, disease monitoring, and guiding therapy in refractory diseases such as tumors and neurodegenerative diseases. We also summarize the current applications of exosomes, especially engineered exosomes, for efficient drug delivery, targeted therapies, gene therapies, and immune vaccines. Finally, the current challenges and potential research directions for the clinical application of exosomes are also discussed. In conclusion, exosomes, as an emerging molecule that can be used in the diagnosis and treatment of diseases, combined with multidisciplinary innovative solutions, will play an important role in clinical applications.

Optical imaging detection of extracellular vesicles of miR-146 modified bone marrow mesenchymal stem cells promoting spinal cord injury repair

Bone Marrow mesenchymal Stem Cells (BMSCs) are considered as an important source of cells for regenerative medicine, In particular, Bone Marrow mesenchymal Stem Cells Exosomes (BMSCs-EXO) have the most significant effect in the treatment of Spinal Cord Injury (SCI), but the mechanism of action is still unknown. This study found that compared with other SCI groups, BMSCs-EXO loaded with miR-146a could significantly improve the functional recovery of the hind limbs of SCI rats. Hematoxylin and eosin (H&E) indicated that the lesion area of spinal cord injury was less, nissl staining indicated that the number of nissl bodies remained more; the mechanism may be through inhibiting the expression of IRAK1 and TRAF6, blocking the activation of NF-κB p65, reducing the expression of TNF-α, IL-1β and IL-6 inflammatory factors and oxidative stress, improving the SCI microenvironment, and promoting the repair of neural function. In general, we found that BMSCs-EXO loaded with miR-146a could reduce the inflammatory response and oxidative stress in SCI by inhibiting the activation of IRAK1/TRAF6/NF-κB p65 signaling pathway, and promote the recovery of neurological function in SCI rats.

Exploring the molecular mechanisms of MSC-derived exosomes in Alzheimer's disease: Autophagy, insulin and the PI3K/Akt/mTOR signaling pathway

Alzheimer's disease (AD) is a devastating neurological condition characterized by cognitive decline, motor coordination impairment, and amyloid plaque accumulation. The underlying molecular mechanisms involve oxidative stress, inflammation, and neuronal degeneration. This study aimed to investigate the therapeutic effects of mesenchymal stem cell-derived exosomes (MSC-exos) on AD and explore the molecular pathways involved, including the PI3K/Akt/mTOR axis, autophagy, and neuroinflammation. To assess the potential of MSC-exos for the treatment of AD, rats were treated with AlCl3 (17 mg/kg/once/day) for 8 weeks, followed by the administration of an autophagy activator (rapamycin), or MSC-exos with or without an autophagy inhibitor (3-methyladenin; 3-MA+ chloroquine) for 4 weeks. Memory impairment was tested, and brain tissues were collected for gene expression analyses, western blotting, histological studies, immunohistochemistry, and transmission electron microscopy. Remarkably, the administration of MSC-exos improved memory performance in AD rats and reduced the accumulation of amyloid-beta (Aβ) plaques and tau phosphorylation. Furthermore, MSC-exos promoted neurogenesis, enhanced synaptic function, and mitigated astrogliosis in AD brain tissues. These beneficial effects were associated with the modulation of autophagy and the PI3K/Akt/mTOR signalling pathway, as well as the inhibition of neuroinflammation. Additionally, MSC-exos were found to regulate specific microRNAs, including miRNA-21, miRNA-155, miRNA-17-5p, and miRNA-126-3p, further supporting their therapeutic potential. Histopathological and bioinformatic analyses confirmed these findings. This study provides compelling evidence that MSC-exos hold promise as a potential therapeutic approach for AD. By modulating the PI3K/Akt/mTOR axis, autophagy, and neuroinflammation, MSC-exos have the potential to improve memory, reduce Aβ accumulation, enhance neurogenesis, and mitigate astrogliosis. These findings shed light on the therapeutic potential of MSC-exos and highlight their role in combating AD.

Evaluation of Tumorigenic Properties of MDA-MB-231 Cancer Stem Cells Cocultured with Telocytes and Telocyte-Derived Mitochondria Following miR-146a Inhibition

Telocytes have some cytoplasmic extensions called telopodes, which are thought to play a role in mitochondrial transfer in intercellular communication. Besides, it is hypothesized that telocytes establish cell membrane-mediated connections with breast cancer cells in coculture and may contribute to the survival of neoplastic cell clusters together with other stromal cells. The aim of this study is to investigate the contribution of telocytes and telocyte-derived mitochondria, which have also been identified in breast tumors, to the tumor development of breast cancer stem cells (CSCs) via miR-146a-5p. The isolation/characterization of telocytes from bone marrow mononuclear cells and the isolation of mitochondria from these cells were performed, respectively. In the next step, CSCs were isolated from the MDA-MB-231 cell line and were characterized. Then, miR-146a-5p expressions of CSCs were inhibited by anti-miR-146a-5p. The epithelial-mesenchymal transition (EMT) was determined by evaluating changes in vimentin protein levels and was evaluated by analyzing BRCA1, P53, SOX2, E-cadherin, and N-cadherin gene expression changes. Our results showed that miR-146a promoted stemness and oncogenic properties in CSCs. EMT (N-cadherin, vimentin, E-cadherin) and tumorigenic markers (BRCA1, P53, SOX2) of CSCs decreased after miR-146a inhibition. Bone marrow-derived telocytes and mitochondria derived from telocytes favored the reduction of CSC aggressiveness following this inhibition.

Role of mesenchymal stem cell-derived exosomes in the regeneration of different tissues

Exosomes are nanovesicles with multiple components used in several applications. Mesenchymal stem cells (MSCs) are well known for their great potential in clinical applications. MSC-derived exosomes (MSC-Exos) have been shown to mediate tissue regeneration in various diseases, including neurological, autoimmune, and inflammatory diseases, cancer, ischemic heart disease, lung injury, and liver fibrosis. They can modulate the immune response by interacting with immune effector cells in the presence of anti-inflammatory compounds and are involved in intercellular communication through various types of cargo. This review summarizes the MSC-Exos-mediated tissue regeneration in various diseases, including neurological, cardiovascular, liver, kidney, articular cartilage, and oral tissue applications. In addition, we discuss the challenges and prospects of MSC-Exos in tissue regeneration.

A comprehensive insight into the immunomodulatory role of MSCs-derived exosomes (MSC-Exos) through modulating pattern-recognition receptors (PRRs)

Mesenchymal stem cell-derived exosomes (MSC-Exos) are emerging as remarkable agents in the field of immunomodulation with vast potential for diagnosing and treating various diseases, including cancer and autoimmune disorders. These tiny vesicles are laden with a diverse cargo encompassing proteins, nucleic acids, lipids, and bioactive molecules, offering a wealth of biomarkers and therapeutic options. MSC-Exos exhibit their immunomodulatory prowess by skillfully regulating pattern-recognition receptors (PRRs). They conduct a symphony of immunological responses, modulating B-cell activities, polarizing macrophages toward anti-inflammatory phenotypes, and fine-tuning T-cell activity. These interactions have profound implications for precision medicine, cancer immunotherapy, autoimmune disease management, biomarker discovery, and regulatory approvals. MSC-Exos promises to usher in a new era of tailored therapies, personalized diagnostics, and more effective treatments for various medical conditions. As research advances, their transformative potential in healthcare becomes increasingly evident.

The potential role of SNHG16/ miRNA-146a/ TRAF6 signaling pathway in the protective effect of zoledronate against colorectal cancer and associated osteoporosis in mouse model

Bone fracture as a consequence of colorectal cancer (CRC) and associated osteoporosis (OP) is considered a risk factor for increasing the mortality rate among CRC patients. SNHG16/ miRNA-146a/ TRAF6 signaling pathway is a substantial contributor to neoplastic evolution, progression, and metastasis. Here, we investigated the effect of zoledronate (ZOL) on the growth of CRC and associated OP in a mouse model. Thirty Balb/c mice were divided into Naïve, azoxymethane (AOM)/dextran sodium sulfate (DSS), and ZOL groups. Body weight and small nucleolar RNA host gene 16 (SNHG16) expression, microRNA-146a, and TRAF6 in bone, colon, and stool were investigated. Samples of colon and bone were collected and processed for light microscopic, immunohistochemical staining for cytokeratin 20 (CK20), nuclear protein Ki67 (pKi-67), and caudal type homeobox transcription factor 2 (CDx2) in colon and receptor activator of nuclear factor kB (RANK) and osteoprotegerin (OPG) in bone. A computerized tomography (CT) scan of the femur and tibia was studied. ZOL produced a significant decrease in the expression of SNHG16 and TRAF6 and an increase in miRNA-146a in the colon and bone. ZOL administration improved the histopathological changes in the colon, produced a significant decrease in CK20 and Ki-67, and increased CDx2 expressions. In bone, ZOL prevented osteoporotic changes and tumour cell invasion produced a significant decrease in RANK and an increase in OPG expressions, alongside improved bone mineral density in CT scans. ZOL could be a promising preventive therapy against colitis-induced cancer and associated OP via modulation expression of SNHG16, miRNA-146a, and TRAF6.

Targeting Inflammation and Oxidative Stress to Improve Outcomes in a TNBS Murine Crohn's Colitis Model

Inflammation and oxidative stress are implicated in the pathogenesis of Crohn's disease. Cerium oxide nanoparticle (CNP) conjugated to microRNA 146a (miR146a) (CNP-miR146a) is a novel compound with anti-inflammatory and antioxidative properties. We hypothesized that local administration of CNP-miR146a would improve colitis in a 2,4,6-Trinitrobenzenesulfonic acid (TNBS) mouse model for Crohn's disease by decreasing colonic inflammation. Balb/c mice were instilled with TNBS enemas to induce colitis. Two days later, the mice received cellulose gel enema, cellulose gel with CNP-miR146a enema, or no treatment. Control mice received initial enemas of 50% ethanol and PBS enemas on day two. The mice were monitored daily for weight loss and clinical disease activity. The mice were euthanized on days two or five to evaluate their miR146a expression, inflammation on histology, and colonic IL-6 and TNF gene expressions and protein concentrations. CNP-miR146a enema successfully increased colonic miR146a expression at 12 h following delivery. At the end of five days from TNBS instillation, the mice treated with CNP-miR146a demonstrated reduced weight loss, improved inflammation scores on histology, and reduced gene expressions and protein concentrations of IL-6 and TNF. The local delivery of CNP-miR146a in a TNBS mouse model of acute Crohn's colitis dramatically decreased inflammatory signaling, resulting in improved clinical disease.

MiR-146a alleviates inflammatory bowel disease in mice through systematic regulation of multiple genetic networks

Introduction

Inflammatory bowel disease (IBD) is a chronic disease involving multiple genes, and the current available targeted drugs for IBD only deliver moderate efficacy. Whether there is a single gene that systematically regulates IBD is not yet known. MiR-146a plays a pivotal role in repression of innate immunity, but its function in the intestinal inflammation is sort of controversy, and the genetic regulatory networks regulated by miR-146a in IBD has not been revealed.

Methods

RT-qPCR was employed to detect the expression of miR-146a in IBD patients and in a mouse IBD model induced by dextran sulfate sodium (DSS), and then we generated a miR-146a knock-out mouse line with C57/Bl6N background. The disease activity index was scored in DSS-treated miR-146a deficiency mice and their wild type (WT) littermates. Bulk RNA-sequencing, RT-qPCR and immunostaining were done to illustrate the downstream genetic regulatory networks of miR-146a in flamed colon. Finally, the modified miR-146a mimics were used to treat DSS-induced IBD in miR-146a knock-out and WT IBD mice.

Results

We showed that the expression of miR-146a in the colon was elevated in dextran sulfate sodium (DSS)-induced IBD mice and patients with IBD. DSS induced dramatic body weight loss and more significant rectal bleeding, shorter colon length, and colitis in miR-146a knock-out mice than WT mice. The miR-146a mimics alleviated DSS-induced symptoms in both miR-146a-/- and WT mice. Further RNA sequencing illustrated that the deficiency of miR-146a de-repressed majority of DSS-induced IBD-related genes that cover multiple genetic regulatory networks in IBD, and supplementation with miR-146a mimics inhibited the expression of many IBD-related genes. Quantitative RT-PCR or immunostaining confirmed that Ccl3, Saa3, Csf3, Lcn2, Serpine1, Serpine2, MMP3, MMP8, MMP10, IL1A, IL1B, IL6, CXCL2, CXCL3, S100A8, S100A9, TRAF6, P65, p-P65, and IRAK1 were regulated by miR-146a in DSS induced IBD. Among them, MMP3, MMP10, IL6, IL1B, S100A8, S100A9, SERPINE1, CSF3, and IL1A were involved in the active stage of IBD in humans.

Discussion

Our date demonstrated that miR-146a acts as a top regulator in C57/BL6N mice to systematically repress multiple genetic regulatory networks involved in immune response of intestine to environment factors, and combinatory treatment with miR-146a-5p and miR-146a-3p mimics attenuates DSS-induced IBD in mice through down-regulating multiple genetic regulatory networks which were increased in colon tissue from IBD patients. Our findings suggests that miR-146a is a top inhibitor of IBD, and that miR-146a-5p and miR-146a-3p mimics might be potential drug for IBD.

Unveiling the Potential of Extracellular Vesicles as Biomarkers and Therapeutic Nanotools for Gastrointestinal Diseases

Extracellular vesicles (EVs), acting as inherent nanocarriers adept at transporting a range of different biological molecules such as proteins, lipids, and genetic material, exhibit diverse functions within the gastroenteric tract. In states of normal health, they participate in the upkeep of systemic and organ homeostasis. Conversely, in pathological conditions, they significantly contribute to the pathogenesis of gastrointestinal diseases (GIDs). Isolating EVs from patients' biofluids facilitates the discovery of new biomarkers that have the potential to offer a rapid, cost-effective, and non-invasive method for diagnosing and prognosing specific GIDs. Furthermore, EVs demonstrate considerable therapeutic potential as naturally targeted physiological carriers for the intercellular delivery of therapeutic cargo molecules or as nanoscale tools engineered specifically to regulate physio-pathological conditions or disease progression. Their attributes including safety, high permeability, stability, biocompatibility, low immunogenicity, and homing/tropism capabilities contribute to their promising clinical therapeutic applications. This review will delve into various examples of EVs serving as biomarkers or nanocarriers for therapeutic cargo in the context of GIDs, highlighting their clinical potential for both functional and structural gastrointestinal conditions. The versatile and advantageous properties of EVs position them as promising candidates for innovative therapeutic strategies in advancing personalized medicine approaches tailored to the gastroenteric tract, addressing both functional and structural GIDs.

Synergistic effects of mesenchymal stem cell-derived extracellular vesicles and dexamethasone on macrophage polarization under inflammatory conditions

The undesirable inflammation and the excessive M1 macrophage activity may lead to inflammatory diseases. Corticosteroids and stem cell therapy are used in clinical practice to promote anti-inflammatory responses. However, this protocol has limitations and is associated with numerous side effects. In this study, the synergistic anti-inflammatory effects of dexamethasone (Dex) and mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) were evaluated to enhance the polarization of M1 inflammatory macrophages into the anti-inflammatory (M2) phenotype. Hence, we designed different combinations of Dex and EVs using three methods, including EVs isolated from Dex-preconditioned MSCs (Pre-Dex-EVs), EVs loaded with Dex (L-Dex-EVs), and EVs and Dex co-administration (Dex + EVs). All designed EVs had a significant effect on reducing the expression of M1-related genes (iNOS, Stat1, and IRF5), cytokines (IL6 and TNF-a), and CD markers (CD86) in lipopolysaccharide-stimulated macrophages. On the other hand, these combinations promoted the expression of alternative-activated M2-related genes (Arg-1, Stat6, and IRF4), cytokine (IL10), and CD markers (CD206).The combination of Dex and MSC-EVs enhances the effectiveness of both and synergistically promotes the conversion of inflammatory macrophages into an anti-inflammatory state.

Challenges and opportunities in inflammatory bowel disease: from current therapeutic strategies to organoid-based models

BACKGROUND

Inflammatory bowel disease (IBD) is an increasingly prevalent global health concern that has garnered substantial attention. However, the underlying mechanisms are still unclear and the current treatments have significant limitations. Intestinal organoids provide an in vitro model to explore the pathogenesis, test the therapeutic effects, and develop regenerative treatments as well as offer the potential to transform drug discovery of IBD.

METHODS

To advance our understanding of the whole story of IBD spanning from the pathogenesis to the current therapeutic strategies and latest advancements, a comprehensive search of major databases including PubMed, Scopus, and Web of Science was conducted to retrieve original articles and reviews related to IBD, organoids, pathogenesis and therapy.

RESULTS

This review deciphers the etiopathogenesis and the current therapeutic approaches in the treatment of IBD. Notably, critical aspects of intestinal organoids in IBD, such as their potential applications, viability, cell renewal ability, and barrier functionality are highlighted. We also discuss the advances, limitations, and prospects of intestinal organoids for precision medicine.

CONCLUSION

The latest strides made in research about intestinal organoids help elucidate intricate aspects of IBD pathogenesis, and pave the prospective avenues for novel therapeutic interventions.

HIF1α/miR-146α/TRAF6/NF-κB axis modulates hepatic iron overload-induced inflammation

Transfusional therapy is used to cure anemia but raises the risk of hepatic iron overload (IO), which triggers oxidative stress damage, inflammation, and failure even fibrosis. microRNAs play a vital role in developing hepatic diseases. This study presented the mechanism by which IO induce hepatic inflammation through microRNAs. In this study, microRNA expression profiling in the liver was observed after IO for 2 weeks, in which the target microRNA will be found. IO activating the miR-146α/TRAF6/NF-κB pathway was validated, and the molecular mechanism of the IO-induced decrease of miR-146α in the liver was studied in vivo and in vitro. The expression of TRAF6/NF-κB (p65)-dependent inflammatory factors increased, whereas the expression of miR-146α decreased during the IO-induced inflammatory response in the liver. The reduced expression of HNF4α caused by HIF1α and miR-34α may decrease the expression of miR-146α. Overexpression of miR-146α alleviated the hepatic inflammatory response caused by IO. Our findings indicate that miR-146α is a key factor in inducing hepatic IO inflammation, which will be another potential target to prevent IO-induced hepatic damage.

Therapeutic potential of mesenchymal stem cell-derived exosomes for allergic airway inflammation

Due to their immunomodulatory capacities, mesenchymal stem cells (MSCs) have been extensively used as therapeutic approaches in cell-based therapy for various inflammatory diseases. Several lines of studies have shown that the most beneficial effects of MSCs are associated with MSC-derived exosomes. Exosomes are nanoscale extracellular vesicles that contain important biomolecules such as RNA, microRNAs (miRNAs), DNA, growth factors, enzymes, chemokines, and cytokines that regulate immune cell functions and parenchymal cell survival. Recently, exosomes, especially MSC-derived exosomes, have been shown to have protective effects in allergic airway inflammation. This review focused on the immune-regulatory potential of MSC-derived exosomes as nanoscale delivery systems in the treatment of allergic airway inflammation.

MicroRNAs: Key modulators of inflammation-associated diseases

Inflammation is a multifaceted biological and pathophysiological response to injuries, infections, toxins, and inflammatory mechanisms that plays a central role in the progression of various diseases. MicroRNAs (miRNAs) are tiny, 19-25 nucleotides long, non-coding RNAs that regulate gene expression via post-transcriptional repression. In this review, we highlight the recent findings related to the significant roles of miRNAs in regulating various inflammatory cascades and immunological processes in the context of many lifestyle-related diseases such as diabetes, cardiovascular diseases, cancer, etc. We also converse on how miRNAs can have a dual impact on inflammatory responses, suggesting that regulation of their functions for therapeutic purposes may be disease-specific.

Understanding exosomes: Part 2-Emerging leaders in regenerative medicine

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of diseases/conditions. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be developed. Today exosomes have been applied in numerous contexts including neurodegenerative disorders (Alzheimer's disease, central nervous system, depression, multiple sclerosis, Parkinson's disease, post-traumatic stress disorders, traumatic brain injury, peripheral nerve injury), damaged organs (heart, kidney, liver, stroke, myocardial infarctions, myocardial infarctions, ovaries), degenerative processes (atherosclerosis, diabetes, hematology disorders, musculoskeletal degeneration, osteoradionecrosis, respiratory disease), infectious diseases (COVID-19, hepatitis), regenerative procedures (antiaging, bone regeneration, cartilage/joint regeneration, osteoarthritis, cutaneous wounds, dental regeneration, dermatology/skin regeneration, erectile dysfunction, hair regrowth, intervertebral disc repair, spinal cord injury, vascular regeneration), and cancer therapy (breast, colorectal, gastric cancer and osteosarcomas), immune function (allergy, autoimmune disorders, immune regulation, inflammatory diseases, lupus, rheumatoid arthritis). This scoping review is a first of its kind aimed at summarizing the extensive regenerative potential of exosomes over a broad range of diseases and disorders.

Exploring the role of IL-1β in inflammatory bowel disease pathogenesis

Interleukin 1β (IL-1β) is a significant mediator of inflammation and tissue damage in IBD. The balance between IL-1β and its endogenous inhibitor-IL-1Ra-, plays a critical role in both initiation and regulation of inflammation. However, the precise role of IL-1β as a causative factor in IBD or simply a consequence of inflammation remains unclear. This review summarizes current knowledge on the molecular and cellular characteristics of IL-1β, describes the existing evidence on the role of this cytokine as a modulator of intestinal homeostasis and an activator of inflammatory responses, and also discusses the role of microRNAs in the regulation of IL-1β-related inflammatory responses in IBD. Current evidence indicates that IL-1β is involved in several aspects during IBD as it greatly contributes to the induction of pro-inflammatory responses through the recruitment and activation of immune cells to the gut mucosa. In parallel, IL-1β is involved in the intestinal barrier disruption and modulates the differentiation and function of T helper (Th) cells by activating the Th17 cell differentiation, known to be involved in the pathogenesis of IBD. Dysbiosis in the gut can also stimulate immune cells to release IL-1β, which, in turn, promotes inflammation. Lastly, increasing evidence pinpoints the central role of miRNAs involvement in IL-1β-related signaling during IBD, particularly in the maintenance of homeostasis within the intestinal epithelium. In conclusion, given the crucial role of IL-1β in the promotion of inflammation and immune responses in IBD, the targeting of this cytokine or its receptors represents a promising therapeutic approach. Further research into the IL-1β-associated post-transcriptional modifications may elucidate the intricate role of this cytokine in immunomodulation.

Extracellular Vesicles: Novel Potential Therapeutic Agents in Inflammatory Bowel Diseases

Patients affected by inflammatory bowel diseases (IBD) can nowadays benefit from a growing number of pharmacological options. However, in moderate-to-severe cases, the therapeutic response is still far from optimal, and treatment changes and optimizations are often required. Thus, researchers in this field are strongly engaged in studies aiming to identify new potential therapeutic targets. Extracellular vesicles (EVs) are tiny subcellular bodies with a phospholipid bilayer envelope containing bioactive molecules, which are released from different cells and are involved in intercellular communication. Recent pre-clinical data show their emerging role in the pathogenesis and treatment of IBD. In our review, we summarize current evidence about the function of EVs as active therapeutic agents in ulcerative colitis and Crohn's disease, analyzing the properties of EVs derived from different cellular sources and the mechanisms through which they may improve intestinal inflammation.

Polyethylene glycol precipitation is an efficient method to obtain extracellular vesicle-depleted fetal bovine serum

Mesenchymal stromal/stem cell derived-extracellular vesicles (MSC-EVs) have gained interest as drug delivery nanoparticles, having immunoregulatory and potentiating tissue repair property. To maintain growth of MSCs and obtain pure MSC-derived EVs, the culture media should contain fetal bovine serum (FBS) devoid of EVs, as the presence of FBS EVs confounds the properties of MSC-EVs. Therefore, we tested three methods: 18h ultracentrifugation (UC) and ultrafiltration (UF), which are common FBS EV depletion methods in current MSC-EV research, and polyethylene glycol (PEG) precipitation to obtain three EV depleted FBS (EVdFBS) batches, and compared them to FBS and commercial (Com) EVdFBS on human adipose stem cell (hADSC) growth, differentiation, enrichment of EVs in hADSC supernatant and their biological function on collagen metabolism. Our comparative study showed UC and UF vary in terms of depletion efficiency and do not completely deplete EVs and affects the growth-promoting quality of FBS. Specifically, FBS EV depletion was comparable between PEG (95.6%) and UF (96.6%) but less by UC (82%), as compared to FBS. FBS protein loss was markedly different among PEG (47%), UF (87%), and UC (51%), implying the ratio of EV depletion over protein loss was PEG (2.03), UF (1.11), and UC (1.61). A significant decrease of TGFβ/Smad signaling, involving in MSC growth and physiology, was observed by UF. After 96 hours of exposure to 5% FBS or 5% four different EVdFBS cell growth media, the osteogenesis ability of hADSCs was not impaired but slightly lower mRNA expression level of Col2a observed in EVdFBS media during chondrogenesis. In consistent with low confluency of hADSCs observed by optical microscope, cell proliferation in response to 5% UF EVdFBS media was inhibited significantly. Importantly, more and purer ADSCs EVs were obtained from ADSCs cultured in 5% PEG EVdFBS media, and they retained bioactive as they upregulated the expression of Col1a1, TIMP1 of human knee synovial fibroblast. Taken together, this study showed that PEG precipitation is the most efficient method to obtain EV depleted FBS for growth of MSCs, and to obtain MSC EVs with minimal FBS EV contamination.

The significance of long non-coding RNAs in the pathogenesis, diagnosis and treatment of inflammatory bowel disease

Inflammatory bowel diseases (IBD) are a group of chronic relapsing gastrointestinal inflammatory diseases with significant global incidence. Although the pathomechanism of IBD has been extensively investigated, several aspects of its pathogenesis remain unclear. Long non-coding RNAs (lncRNAs) are transcripts with more than 200 nucleotides in length that have potential protein-coding functions. LncRNAs play important roles in biological processes such as epigenetic modification, transcriptional regulation and post-transcriptional regulation. In this review, we summarize recent advances in research on IBD-related lncRNAs from the perspective of the overall intestinal microenvironment, as well as their potential roles as immune regulators, diagnostic biomarkers and therapeutic targets or agents for IBD.

Dual impacts of mesenchymal stem cell-derived exosomes on cancer cells: unravelling complex interactions

Mesenchymal stem cells (MSCs) are multipotent, self-renewing stromal cells found in a variety of adult tissues. MSCs possess a remarkable ability to migrate towards tumor sites, known as homing. This homing process is mediated by various factors, including chemokines, growth factors, and extracellular matrix components present in the tumor microenvironment. MSCs release extracellular vesicles known as exosomes (MSC-Exos), which have been suggested to serve a key role in mediating a wide variety of MSC activities. Through cell-cell communication, MSC-Exos have been shown to alter recipient cell phenotype or function and play as a novel cell-free alternative for MSC-based cell therapy. However, MSC recruitment to tumors allows for their interaction with cancer cells and subsequent regulation of tumor behavior. MSC-Exos act as tumor niche modulators via transferring exosomal contents, such as specific proteins or genetic materials, to the nearby cancer cells, leading to either promotion or suppression of tumorigenesis, angiogenesis, and metastasis, depending on the specific microenvironmental cues and recipient cell characteristics. Consequently, there is still a debate about the precise relationship between tumor cells and MSC-Exos, and it is unclear how MSC-Exos impacts tumor cells. Although the dysregulation of miRNAs is caused by the progression of cancer, they also play a direct role in either promoting or inhibiting tumor growth as they act as either oncogenes or tumor suppressors. The utilization of MSC-Exos may prove to be an effective method for restoring miRNA as a means of treating cancer. This review aimed to present the existing understanding of the impact that MSC-Exos could have on cancer. To begin with, we presented a brief explanation of exosomes, MSCs, and MSC-Exos. Following this, we delved into the impact of MSC-Exos on cancer growth, EMT, metastasis, angiogenesis, resistance to chemotherapy and radiotherapy, and modulation of the immune system. Opposing effects of mesenchymal stem cells-derived exosomes on cancer cells.

Anti-inflammatory effect of interleukin-6 highly enriched in secretome of two clinically relevant sources of mesenchymal stromal cells

Despite several advances in the field of regenerative medicine, clinical management of extensive skin wounds or burns remains a major therapeutic issue. During the past few years, Mesenchymal Stromal Cells (MSCs) have emerged as a novel therapeutic tool to promote tissue repair through their anti-inflammatory, pro-trophic and pro-remodeling effects. They exert their biological activity mainly via the secretion of soluble bioactive molecules such as cytokines, growth factors, proteins and microRNAs which can be encapsulated within extracellular vesicles (EV). The recent discovery of their high plasticity to external stimuli has fostered the development of new targeted therapies known as priming strategies, to enhance their potential. Our team recently showed that Interleukin-1β (IL-1β)-primed gingival MSCs promote wound healing and epidermal engraftment in vitro, and in vivo through their secreted products that contain extracellular vesicles. In the present work, we investigated whether two common sources of MSCs, gingiva and bone marrow, could respond similarly to IL-1β to favor pro-healing capabilities of their secretome. We showed that both primed-MSC sources, or their related secreted products, are able to reduce inflammation in LPS-challenged human monocytic THP-1 cell line. IL-1β priming enhanced MSC secretion of wound healing-related growth factors, cytokines and miRNAs in both sources. Among them, interleukin 6 was shown to be involved in the anti-inflammatory effect of MSC secreted products. Overall, these results underline the pro-healing properties of both MSC sources and their secretome upon IL-1β priming and their potential to improve the current medical treatment of severe wounds.

The developing role of extracellular vesicles in autoimmune diseases: special attention to mesenchymal stem cell-derived extracellular vesicles

Autoimmune diseases are complex, chronic inflammatory conditions initiated by the loss of immunological tolerance to self-antigens. Nowadays, there is no effective and useful therapy for autoimmune diseases, and the existing medications have some limitations due to their nonspecific targets and side effects. During the last few decades, it has been established that mesenchymal stem cells (MSCs) have immunomodulatory functions. It is proposed that MSCs can exert an important therapeutic effect on autoimmune disorders. In parallel with these findings, several investigations have shown that MSCs alleviate autoimmune diseases. Intriguingly, the results of studies have demonstrated that the effective roles of MSCs in autoimmune diseases do not depend on direct intercellular communication but on their ability to release a wide spectrum of paracrine mediators such as growth factors, cytokines and extracellular vehicles (EVs). EVs that range from 50 to 5,000 nm were produced by almost any cell type, and these nanoparticles participate in homeostasis and intercellular communication via the transfer of a broad range of biomolecules such as modulatory proteins, nucleic acids (DNA and RNA), lipids, cytokines, and metabolites. EVs derived from MSCs display the exact properties of MSCs and can be safer and more beneficial than their parent cells. In this review, we will discuss the features of MSCs and their EVs, EVs biogenesis, and their cargos, and then we will highlight the existing discoveries on the impacts of EVs from MSCs on autoimmune diseases such as multiple sclerosis, arthritis rheumatic, inflammatory bowel disease, Type 1 diabetes mellitus, systemic lupus erythematosus, autoimmune liver diseases, Sjögren syndrome, and osteoarthritis, suggesting a potential alternative for autoimmune conditions therapy.

MicroRNA-146a negatively regulates inflammation via the IRAK1/TRAF6/NF-κB signaling pathway in dry eye

Inflammation is a key factor in the pathogenesis of dry eye disease (DED). We aimed to investigate the role of microRNA-146a (miR-146a) in regulating corneal inflammation in a mouse model of benzalkonium chloride (BAC)-induced dry eye and the TNF-α-induced NF-κB signaling pathway in human corneal epithelial cells (HCECs). A mouse model of dry eye was established by administering with BAC to BALB/c mice, and the expression of TNF-α, IL-1β, IL-6, IL-8, cyclooxygenase 2 (COX2), interleukin-1 receptor-associated kinase 1 (IRAK1) and TNF receptor-associated factor 6 (TRAF6) in the corneas of dry eye model mice was significantly increased; this was accompanied by the upregulation of miR-146a and activation of the NF-κB pathway. In vitro, TNF-α induced miR-146a expression in HCECs, while the NF-κB inhibitor SC-514 reduced the expression of miR-146a. Overexpression of miR-146a decreased the expression of IRAK1 and TRAF6, which have been identified as targets of miR-146a. Furthermore, overexpression of miR-146a suppressed NF-κB p65 translocation from the cytoplasm to the nucleus. Moreover, overexpression of miR-146a attenuated the TNF-α-induced expression of IL-6, IL-8, COX2 and intercellular adhesion molecule 1 (ICAM1), while inhibition of miR-146a exerted the opposite effect. Our results suggest that miR-146a mediates the inflammatory response in DED. MiR-146a negatively regulates inflammation in HCECs through the IRAK1/TRAF6/NF-κB pathway, and this may serve as a potential therapeutic approach for the treatment of DED.

Biogenesis, Composition and Potential Therapeutic Applications of Mesenchymal Stem Cells Derived Exosomes in Various Diseases

Exosomes are nanovesicles with a wide range of chemical compositions used in many different applications. Mesenchymal stem cell-derived exosomes (MSCs-EXOs) are spherical vesicles that have been shown to mediate tissue regeneration in a variety of diseases, including neurological, autoimmune and inflammatory, cancer, ischemic heart disease, lung injury, and liver fibrosis. They can modulate the immune response by interacting with immune effector cells due to the presence of anti-inflammatory compounds and are involved in intercellular communication through various types of cargo. MSCs-EXOs exhibit cytokine storm-mitigating properties in response to COVID-19. This review discussed the potential function of MSCs-EXOs in a variety of diseases including neurological, notably epileptic encephalopathy and Parkinson's disease, cancer, angiogenesis, autoimmune and inflammatory diseases. We provided an overview of exosome biogenesis and factors that regulate exosome biogenesis. Additionally, we highlight the functions and potential use of MSCs-EXOs in the treatment of the inflammatory disease COVID-19. Finally, we covered a strategies and challenges of MSCs-EXOs. Finally, we discuss conclusion and future perspectives of MSCs-EXOs.

Extracellular vesicles and their indispensable roles in pathogenesis and treatment of inflammatory bowel disease: A comprehensive review

Inflammatory bowel disease (IBD) is a global disease with rising incidence worldwide, and its debilitating symptoms and dissatisfactory therapies have brought heavy burdens for patients. Extracellular vesicles (EVs), a heterogeneous population of lipid bilayer membranes containing abundant bioactive molecules, have been indicated to play important roles in the pathogenesis and treatment of many diseases. However, to our knowledge, comprehensive reviews summarizing the various roles of diverse source-derived EVs in the pathogenesis and treatment of IBD are still lacking. This review, not only summarizes the EV characteristics, but also focuses on the multiple roles of diverse EVs in IBD pathogenesis and their treatment potential. In addition, hoping to push forward the research frontiers, we point out several challenges that the researchers are faced, about EVs in current IBD research and future therapeutic applications. We also put forward our prospects on future exploration regarding EVs in IBD treatment, including developing IBD vaccines and paying more attention on apoptotic vesicles. This review is aimed to enrich the knowledge on the indispensable roles of EVs in IBD pathogenesis and treatment, providing ideas and reference for future therapeutic strategy for IBD treatment.

Potential angiogenic, immunomodulatory, and antifibrotic effects of mesenchymal stem cell-derived extracellular vesicles in systemic sclerosis

Systemic sclerosis (SSc) is an intricate systemic autoimmune disease with pathological features such as vascular injury, immune dysregulation, and extensive fibrosis of the skin and multiple organs. Treatment options are limited; however, recently, mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been acknowledged in preclinical and clinical trials as being useful in treating autoimmune diseases and are likely superior to MSCs alone. Recent research has also shown that MSC-EVs can ameliorate SSc and the pathological changes in vasculopathy, immune dysfunction, and fibrosis. This review summarizes the therapeutic effects of MSC-EVs on SSc and the mechanisms that have been discovered to provide a theoretical basis for future studies on the role of MSC-EVs in treating SSc.

Immunomodulation: The next target of mesenchymal stem cell-derived exosomes in the context of ischemic stroke

Ischemic stroke (IS) is the most prevalent form of brain disease, characterized by high morbidity, disability, and mortality. However, there is still a lack of ideal prevention and treatment measures in clinical practice. Notably, the transplantation therapy of mesenchymal stem cells (MSCs) has been a hot research topic in stroke. Nevertheless, there are risks associated with this cell therapy, including tumor formation, coagulation dysfunction, and vascular occlusion. Also, a growing number of studies suggest that the therapeutic effect after transplantation of MSCs is mainly attributed to MSC-derived exosomes (MSC-Exos). And this cell-free mediated therapy appears to circumvent many risks and difficulties when compared to cell therapy, and it may be the most promising new strategy for treating stroke as stem cell replacement therapy. Studies suggest that suppressing inflammation via modulation of the immune response is an additional treatment option for IS. Intriguingly, MSC-Exos mediates the inflammatory immune response following IS by modulating the central nervous system, the peripheral immune system, and immunomodulatory molecules, thereby promoting neurofunctional recovery after stroke. Thus, this paper reviews the role, potential mechanisms, and therapeutic potential of MSC-Exos in post-IS inflammation in order to identify new research targets.

An injectable hydrogel scaffold with IL-1β-activated MSC-derived exosomes for the treatment of endometritis

Chronic endometritis is a common gynecological disease resulting from various long-term recurrent infections, and is closely related to myositis, miscarriage, and even infertility. There is still no satisfactory treatment method currently in clinical therapy. Mesenchymal stem cell (MSC)-derived exosomes, an important kind of paracrine product, have been used to treat inflammatory diseases due to their promising immunomodulatory function and tissue repair ability similar to MSCs. Considering that the exosome contents and functions are regulated by the MSC status and the MSC status is significantly influenced by its surrounding microenvironment, we propose a hypothesis that exosomes derived from inflammation-simulated MSCs will possess stronger inhibition ability for inflammation. Herein, we used IL-1β to activate rat bone MSCs for obtaining β-exo and constructed an injectable polypeptide hydrogel scaffold by loading β-exo (β-exo@pep) for an in situ slow release of β-exo. The results showed that the polypeptide hydrogel can provide a sustained release of exosomes in 14 days. The β-exo@pep composite hydrogel can more effectively inhibit the production of inflammatory factors such as TNF-α, IL-1β, and IFN-γ, while it can promote the production of anti-inflammatory factors such as Arg-1, IL-6, and IL-10. The β-exo@pep composite hydrogel significantly promoted cell migration, invasion, and vessel tube formation in vitro. The experiments in a rat model of endometritis proved that the β-exo@pep composite scaffold possessed excellent ability towards anti-inflammation and endometrial regeneration. The research studies on the molecular mechanism revealed that the protein expressions of HMGB1 and phosphorylated IKB-α and p65 are down-regulated in the cells treated with β-exo@pep, indicating the involvement of the NF-κB signaling pathway. This study provides an effective method for the treatment of chronic endometritis, which is promising for clinical use.

MiRNA-Based Therapies for the Treatment of Inflammatory Bowel Disease: What Are We Still Missing?

Micro-RNAs (miRNAs) are noncoding RNAs usually 24-30 nucleotides long that play a central role in epigenetic mechanisms of inflammatory diseases and cancers. Recently, several studies have assessed the involvement of miRNAs in the pathogenesis of inflammatory bowel disease (IBD) and colitis-associated neoplasia. Particularly, it has been shown that many members of miRNAs family are involved in the pathways of inflammation and fibrogenesis of IBD; therefore, their use as inflammatory and fibrosis biomarkers has been postulated. In light of these results, the role of miRNAs in IBD therapy has been proposed and is currently under investigation with many in vitro and in vivo studies, murine models, and a phase 2a trial. The accumulating data have pushed miRNA-based therapy closer to clinical practice, although many open questions remain. With this systematic review, we discuss the current knowledge about the therapeutic effects of miRNAs mimicking and inhibition, and we explore the new potential targets of miRNA family for the treatment of inflammation and fibrosis in IBD.

Extracellular Vesicles as Therapeutic Resources in the Clinical Environment

The native role of extracellular vesicles (EVs) in mediating the transfer of biomolecules between cells has raised the possibility to use them as therapeutic vehicles. The development of therapies based on EVs is now expanding rapidly; here we will describe the current knowledge on different key points regarding the use of EVs in a clinical setting. These points are related to cell sources of EVs, isolation, storage, and delivery methods, as well as modifications to the releasing cells for improved production of EVs. Finally, we will depict the application of EVs therapies in clinical trials, considering the impact of the COVID-19 pandemic on the development of these therapies, pointing out that although it is a promising therapy for human diseases, we are still in the initial phase of its application to patients.

miRNA Molecules-Late Breaking Treatment for Inflammatory Bowel Diseases?

MicroRNAs (miRNAs) are a group of non-coding RNAs that play a critical role in regulating epigenetic mechanisms in inflammation-related diseases. Inflammatory bowel diseases (IBDs), which primarily include ulcerative colitis (UC) and Crohn's disease (CD), are characterized by chronic recurrent inflammation of intestinal tissues. Due to the multifactorial etiology of these diseases, the development of innovative treatment strategies that can effectively maintain remission and alleviate disease symptoms is a major challenge. In recent years, evidence for the regulatory role of miRNAs in the pathogenetic mechanisms of various diseases, including IBD, has been accumulating. In light of these findings, miRNAs represent potential innovative candidates for therapeutic application in IBD. In this review, we discuss recent findings on the role of miRNAs in regulating inflammatory responses, maintaining intestinal barrier integrity, and developing fibrosis in clinical and experimental IBD. The focus is on the existing literature, indicating potential therapeutic application of miRNAs in both preclinical experimental IBD models and translational data in the context of clinical IBD. To date, a large and diverse data set, which is growing rapidly, supports the potential use of miRNA-based therapies in clinical practice, although many questions remain unanswered.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: New Soldiers in the War on Immune-Mediated Diseases

Inflammatory diseases are a group of debilitating disorders with varying degrees of long-lasting functional impairment of targeted system. New therapeutic agents that will attenuate on-going inflammation and, at the same time, promote regeneration of injured organ are urgently needed for the treatment of autoimmune and inflammatory disorders. During the last decade numerous studies have demonstrated that crucial therapeutic benefits of mesenchymal stem cells (MSCs) in inflammatory diseases are based on the effects of MSC-produced paracrine mediators and not on the activity of engrafted cells themselves. Thus, to overcome the limitations of stem cell transplantation, MSC-derived extracellular vesicles (MSC-EVs) have been rigorously investigated, as a promising cell-free pharmaceutical component. In this review, we focus on the mechanisms of MSC-EV covering the current knowledge on their potential therapeutic applications for immune-mediated diseases.

miRNA-encapsulated abiotic materials and biovectors for cutaneous and oral wound healing: Biogenesis, mechanisms, and delivery nanocarriers

MicroRNAs (miRNAs) as therapeutic agents have attracted increasing interest in the past decade owing to their significant effectiveness in treating a wide array of ailments. These polymerases II-derived noncoding RNAs act through post-transcriptional controlling of different proteins and their allied pathways. Like other areas of medicine, researchers have utilized miRNAs for managing acute and chronic wounds. The increase in the number of patients suffering from either under-healing or over-healing wound demonstrates the limited efficacy of the current wound healing strategies and dictates the demands for simpler approaches with greater efficacy. Various miRNA can be designed to induce pathway beneficial for wound healing. However, the proper design of miRNA and its delivery system for wound healing applications are still challenging due to their limited stability and intracellular delivery. Therefore, new miRNAs are required to be identified and their delivery strategy needs to be optimized. In this review, we discuss the diverse roles of miRNAs in various stages of wound healing and provide an insight on the most recent findings in the nanotechnology and biomaterials field, which might offer opportunities for the development of new strategies for this chronic condition. We also highlight the advances in biomaterials and delivery systems, emphasizing their challenges and resolutions for miRNA-based wound healing. We further review various biovectors (e.g., adenovirus and lentivirus) and abiotic materials such as organic and inorganic nanomaterials, along with dendrimers and scaffolds, as the delivery systems for miRNA-based wound healing. Finally, challenges and opportunities for translation of miRNA-based strategies into clinical applications are discussed.

Therapeutic potential of exosome-based personalized delivery platform in chronic inflammatory diseases

In the inflammatory microenvironment, there are numerous exosomes secreted by immune cells (Macrophages, neutrophils, dendritic cells), mesenchymal stem cells (MSCs) and platelets as intercellular communicators, which participate in the regulation of inflammation by modulating gene expression and releasing anti-inflammatory factors. Due to their good biocompatibility, accurate targeting, low toxicity and immunogenicity, these exosomes are able to selectively deliver therapeutic drugs to the site of inflammation through interactions between their surface-antibody or modified ligand with cell surface receptors. Therefore, the role of exosome-based biomimetic delivery strategies in inflammatory diseases has attracted increasing attention. Here we review current knowledge and techniques for exosome identification, isolation, modification and drug loading. More importantly, we highlight progress in using exosomes to treat chronic inflammatory diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), atherosclerosis (AS), and inflammatory bowel disease (IBD). Finally, we also discuss their potential and challenges as anti-inflammatory drug carriers.

Mesenchymal Stem Cell-Derived Apoptotic Bodies: Biological Functions and Therapeutic Potential

Mesenchymal stem cells (MSCs) are non-hematopoietic progenitor cells with self-renewal ability and multipotency of osteogenic, chondrogenic, and adipogenic differentiation. MSCs have appeared as a promising approach for tissue regeneration and immune therapies, which are attributable not only to their differentiation into the desired cells but also to their paracrine secretion. MSC-sourced secretome consists of soluble components including growth factors, chemokines, cytokines, and encapsulated extracellular vesicles (EVs). Apoptotic bodies (ABs) are large EVs (diameter 500𠀓2000 nm) harboring a variety of cellular components including microRNA, mRNA, DNA, protein, and lipids related to the characteristics of the originating cell, which are generated during apoptosis. The released ABs as well as the genetic information they carry are engulfed by target cells such as macrophages, dendritic cells, epithelial cells, and fibroblasts, and subsequently internalized and degraded in the lysosomes, suggesting their ability to facilitate intercellular communication. In this review, we discuss the current understanding of the biological functions and therapeutic potential of MSC-derived ABs, including immunomodulation, tissue regeneration, regulation of inflammatory response, and drug delivery system.

Immunomodulatory and Regenerative Effects of MSC-Derived Extracellular Vesicles to Treat Acute GVHD

The development of human mesenchymal stromal/stem cell (MSC)-based therapy has focused on exploring biological nanoparticles secreted from MSCs. There is emerging evidence that the immunomodulatory and regenerative effects of MSCs can be recapitulated by extracellular vesicles released from MSCs (MSC-EVs). Off-the-shelf allogeneic human MSC products are clinically available to treat acute graft-versus-host disease (GVHD), but real-world data have revealed the limitations of these products as well as their feasibility, safety, and efficacy. MSC-EVs may have advantages over parental MSCs as drugs because of their distinguished biodistribution and importantly dose-dependent therapeutic effects. Recent research has shed light on the role of microRNAs in the mode-of-action of MSC-EVs. A group of specific microRNAs alone or in combination with membrane proteins, membrane lipids, and soluble factors present in MSC-EVs play key roles in the regulation of GVHD. In this concise review, we review the regulation of T-cell-mediated adaptive immunity and antigen-presenting cell-mediated innate immunity by MSC-EVs and the direct regenerative effects on damaged cells in association with the immunopathology of GVHD.

Biomarker-based approach to determine etiology and severity of pulmonary hypertension: Focus on microRNA

Pulmonary arterial hypertension (PAH) is characterized by remodeling of the pulmonary arteries, and defined by elevated pulmonary arterial pressure, measured during right heart catheterization. There are three main challenges to the diagnostic and therapeutic process of patients with PAH. First, it is difficult to differentiate particular PAH etiology. Second, invasive diagnostic is required to precisely determine the severity of PAH, and thus to qualify patients for an appropriate treatment. Third, the results of treatment of PAH are unpredictable and remain unsatisfactory. MicroRNAs (miRNAs) are small non-coding RNAs that regulate post transcriptional gene-expression. Their role as a prognostic, and diagnostic biomarkers in many different diseases have been studied in recent years. MiRNAs are promising novel biomarkers in PAH due to their activity in various molecular pathways and processes underlying PAH. Lack of biomarkers to differentiate between particular PAH etiology and evaluate the severity of PAH, as well as paucity of therapeutic targets in PAH open a new field for the possibility to use miRNAs in these applications. In our article, we discuss the potential of miRNAs use as diagnostic tools, prognostic biomarkers and therapeutic targets in PAH.

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.

Tumor necrosis factor alpha delivers exogenous inflammation-related microRNAs to recipient cells with functional targeting capabilities

Tumor necrosis factor alpha (TNF-α) is a critical pro-inflammatory cytokine in a wide range of tumors and infectious diseases. This study showed for the first time that TNF-α could specifically bind to certain intracellular or circulating inflammation-related microRNAs both in vitro and in vivo. The binding sites of TNF-α to microRNAs are located at the N-terminal of TNF-α and the 3'-GGUU motif of microRNAs. TNF-α could deliver exogenous unmodified single-stranded microRNAs into recipient cells through the TNF-α receptors (TNFRs) and stabilize them from being degraded by RNase in cells. Exogenous miR-146a or let-7c delivered into HCT116 cells by TNF-α could escape from lysosomes and specifically downregulate their target genes and then affect cell proliferation and migration in vitro, as well as tumorigenesis in vivo. Based on the above findings, the concept of "non-conjugated ligand-mediated RNA delivery (ncLMRD)" was proposed, which may serve as a promising strategy for therapeutic microRNA delivery in the future.

Extracellular Vesicles of Mesenchymal Stem Cells Are More Effectively Accessed through Polyethylene Glycol-Based Precipitation than by Ultracentrifugation

Extracellular vesicles (EVs) have been identified as cell-cell communication agents, and EVs derived from mesenchymal stem cells (MSCs) exhibit therapeutic effects similar to those of the cells of origin. Precipitation methods have been used extensively for EV harvests, such as UC- (ultracentrifugation-) or PEG- (polyethylene glycol-) based methods, and the difference in EVs derived from MSCs by UC and PEG is not fully understood. We harvested EVs from amniotic fluid MSCs (AF-MSCs) by UC- or PEG-based precipitation methods and conducted a comparison study of those EVs derived by the two methods: output, RNA, and protein expression of EVs and EV biological reaction in a THP-1-cell model of LPS induction, which was considered an infection model. There was no difference in morphology, size, or specific marker-positive ratio of PEG-EVs and UC-EVs, but PEG obtained more EV particles, protein, and RNA than the UC method. In our THP-1 model of LPS induction, MSC-EVs did not lead to a change in protein expression but inhibited the LPS-induced increase in cytokine secretion. UC-EVs were more effective for TNF-α inhibition, and PEG-EVs were more effective for IL10 inhibition. Thus, our findings provide evidence that PEG-based precipitation is a more efficient mesenchymal stem cell-extracellular vesicle-derived method than UC.

Mesenchymal (Stem) Stromal Cells Based as New Therapeutic Alternative in Inflammatory Bowel Disease: Basic Mechanisms, Experimental and Clinical Evidence, and Challenges

Inflammatory bowel diseases (IBD) are an example of chronic diseases affecting 40% of the population, which involved tissue damage and an inflammatory process not satisfactorily controlled with current therapies. Data suggest that mesenchymal stem cells (MSC) may be a therapeutic option for these processes, and especially for IBD, due to their multifactorial approaches such as anti-inflammatory, anti-oxidative stress, anti-apoptotic, anti-fibrotic, regenerative, angiogenic, anti-tumor, or anti-microbial. However, MSC therapy is associated with important limitations as safety issues, handling difficulties for therapeutic purposes, and high economic cost. MSC-derived secretome products (conditioned medium or extracellular vesicles) are therefore a therapeutic option in IBD as they exhibit similar effects to their parent cells and avoid the issues of cell therapy. In this review, we proposed further studies to choose the ideal tissue source of MSC to treat IBD, the implementation of new standardized production strategies, quality controls and the integration of other technologies, such as hydrogels, which may improve the therapeutic effects of derived-MSC secretome products in IBD.

Intestine epithelial cell-derived extracellular vesicles alleviate inflammation induced by Clostridioides difficile TcdB through the activity of TGF-β1

Background

Clostridioides difficile infection (CDI) has been primarily associated with the toxin B (TcdB), one of the three known protein toxins secreted by C. difficile, which can activate the intestinal immune system and lead to pathological damage. Even though the biological functions of intestine epithelial cell-derived extracellular vesicles (I-Evs) have been well documented, the role of I-Evs in the process of CDI is still unknown.

Objectives

The protective effect of I-Evs against C. difficile TcdB was investigated both in cultured murine colon carcinoma MC38 cells and a mouse model used in this study.

Results

Mouse I-Evs with mean diameter ranging from 100 to 200 nm and a density of 1.09-1.17 g/mL were obtained and confirmed containing the Ev-associated specific surface markers CD63 and TSG101 as well as high level of TGF-β1. In MC38 cells, I-Evs were able to decrease the gene expression of IL-6, TNF-α, IL-1β, and IL-22 induced by C. difficile TcdB, but to increase both the gene expression and protein levels of TGF-β1. I-Evs treatment via intraperitoneal administration alleviates C. difficile TcdB-induced local colon inflammation in mice and increased their survival rate from 50% up to 80%. Furthermore, I-Evs induced an increase in the proportion of CD4+Foxp3+Tregs in vitro and in vivo through a TGF-β1-dependent mechanism by activating the TGF-β1 pathway and prompting phosphorylation of the downstream proteins Smad 2/3.

Conclusion

For the first time, our study demonstrated that I-Evs originated from intestine epithelial cells can alleviate inflammation induced by C. difficile TcdB both in vitro and in vivo. Therefore, I-Evs might be potentially a novel endogenous candidate for effective treatment of CDI.

Nanoparticles for oral delivery: targeted therapy for inflammatory bowel disease

As a group of chronic and idiopathic gastrointestinal (GI) disorders, inflammatory bowel disease (IBD) is characterized by recurrent intestinal mucosal inflammation. Oral administration is critical for the treatment of IBD. Unfortunately, it is difficult to target the bowel located in the GI tract due to multiple physical barriers. The unique physicochemical properties of nanoparticle-based drug delivery systems (DDSs) and their enhanced permeability and retention effects in the inflamed bowel, render nanomedicines to be used to implement precise drug delivery at diseased sites in IBD therapy. In this review, we described the pathophysiological features of IBD, and designed strategies to exploit these features for intestinal targeting. In addition, we introduced the types of currently developed nano-targeted carriers, including synthetic nanoparticle-based and emerging naturally derived nanoparticles (e.g., extracellular vesicles and plant-derived nanoparticles). Moreover, recent developments in targeted oral nanoparticles for IBD therapy were also highlighted. Finally, we presented challenges associated with nanotechnology and potential directions for future IBD treatment.

Mesenchymal stem cells-derived extracellular vesicles containing miR-378a-3p inhibit the occurrence of inflammatory bowel disease by targeting GATA2

This study sought to determine whether mesenchymal stem cells‐derived extracellular vesicles (MSCs‐EVs) carrying microRNA‐378a‐3p (miR‐378a‐3p) could affect the pathogenesis of inflammatory bowel disease (IBD) by regulating the GATA‐binding protein 2 (GATA2)/aquaporin‐4 (AQP4)/peroxisome proliferator‐activated receptor α (PPAR‐α) axis. Initially, colon mucosa biopsy tissues were harvested from healthy controls and patients with IBD for qRT‐PCR and immunohistochemistry analysis. EVs harvested from MSCs and lipopolysaccharide (LPS) were used to stimulate the M064 cells to establish an in vitro inflammation cell model. Besides, 2,4,6‐trinitrobenzene sulfonic acid intracolon administration was performed to establish in vivo IBD mouse models. After loss‐ and gain‐of‐function assays, the regulatory role of MSCs‐derived EVs loaded with manipulated miR‐378a‐3p in IBD in relation to GATA2/AQP4/PPAR‐α were explored. Upregulation of GATA2 was identified in the colon tissue of IBD patients. GATA2, which was a target gene of miR‐378a‐3p, transcriptionally upregulated AQP4. After silencing of GATA2, LPS‐induced apoptosis of M064 cells was reduced by the downregulation of AQP4. Decreased AQP4 contributed to PPAR‐α pathway inactivation and weakened the LPS‐induced apoptosis of M064 cells. MSCs‐EVs delivering miR‐378a‐3p suppressed the GATA2/AQP4/PPAR‐α pathway, which reduced LPS‐induced apoptosis of M064 cells and the occurrence of IBD in mice. Altogether, the current study illustrated that MSCs‐EVs transfer miR‐378a‐3p to reduce the GATA2 expression, which downregulates AQP4 to block the PPAR‐α signalling pathway, thus suppressing the occurrence of IBD.

Therapeutic role of mesenchymal stem cell-derived exosomes in respiratory disease

Exosomes are extracellular vesicles found in various tissues, blood circulation, and tissue fluids, secreted into the extracellular environment by fusing a multivesicular body with a plasma membrane. Various cell types release these vesicles to contribute to many cellular functions, including intercellular communication, cell proliferation, differentiation, angiogenesis, response to stress, and immune system signaling. These natural nanoparticles have therapeutic effects in various diseases and exhibit a behavior similar to the cell from which they originated. In the meantime, exosomes derived from mesenchymal stem cells have attracted the attention of many researchers and physicians due to their unique ability to modulate the immune system, repair tissue and reduce inflammation. Numerous clinical and preclinical studies have examined the effect of MSC-derived exosomes in various diseases, and their results have been published in prestigious journals. This review article discusses the biogenesis and sources of exosomes, MSC-derived exosomes, the use of these exosomes in regenerative medicine, and treatments based on exosomes derived from stem cells in respiratory diseases.

Application of extracellular vesicles derived from mesenchymal stem cells as potential therapeutic tools in autoimmune and rheumatic diseases

Mesenchymal stem cells (MSCs) have been proven to have superior potential to be used astherapeutic candidates in various disorders. Nevertheless, the clinical application of these cells have been restricted because of their tumorigenic properties. Increasing evidence has established that the valuable impacts of MSCs are mainly attributable to the paracrine factors including extracellular vesicles (EVs). EVs are nanosized double-layer phospholipid membrane vesicles contain various proteins, lipids and miRNAs which mediate cell-to-cell communications. Due to their inferior immunogenicity and tumorigenicity, as well as easier management, EVs have drawn attention as potential cell-free replacement therapy to MSCs. For that reason, herein, we reviewed the recent findings of researches on different MSC-EVs and their effectiveness in the treatment of several autoimmune and rheumatic diseases including multiple sclerosis, inflammatory bowel disease, rheumatoid arthritis, osteoarthritis, osteoporosis, and systemic lupus erythematosus as well as Sjogren's syndrome, systemic sclerosis and other autoimmune diseases.