Role of exosome in autoimmunity, with a particular emphasis on rheumatoid arthritis

Differential expressions and potential clinical values of lncRNAs in the plasma exosomes of rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a common autoimmune disease with unclear pathogenesis. Progress in its clinical diagnosis and treatment mainly depends on the elucidation of its pathogenesis and the exploration of new biomarkers. Exosomes contain various biomolecules, including long non-coding ribonucleic acids (lncRNAs). lncRNAs may participate in the regulation of autoimmune and inflammatory processes during RA pathogenesis by transmitting these biomolecules via exosomes among different cells. Therefore, the investigation of lncRNAs in RA exosomes may be a feasible pathway to elucidate RA pathogenesis, identify new diagnostic biomarkers, and identify potential therapeutic targets.

METHODS

In the first phase of exosomal non-coding RNAs screening, exosomes were isolated from the peripheral blood of six patients with RA and healthy controls (HC). High-throughput RNA sequencing was performed to obtain lncRNA expression profiles, and 15 lncRNAs with the highest differential expression were selected as candidate lncRNAs. In the second phase of validation using real-time quantitative polymerase chain reaction (qRT-PCR), differential expression of the 15 candidate lncRNAs was verified in 42 patients with RA and their matched HC. Their potential value as RA diagnostic biomarkers was assessed using receiver operating characteristic (ROC) curve analysis. Their relationships with common clinical indices of RA were explored using Spearman's rank correlation and linear regression analyses.

RESULT

Compared to HC, patients with RA had 206 upregulated and 2,332 downregulated lncRNAs. Fifteen candidate lncRNAs were validated by qRT-PCR, of which 12 (SNHG6, RPS18P9, RPL21P28, EBLN3P, FAM153CP, RPL23P8, SNHG31, NORAD, H3P6, DLEU2, TUG1, and OIP5-AS1) were upregulated, and three (CXXC4-AS1, OLMALINC, and NPHP3-AS1) were downregulated. In the ROC analysis of the 15 candidate lncRNAs, the area under the curve (AUC) ranged from 0.847 (0.767, 0.927) for OLMALINC to 0.994 (0.984, 1.000) for CXXC4-AS1. Spearman rank correlation analysis revealed erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and disease activity score of 28 (DAS28) were correlated with seven, six, and five lncRNAs, respectively. Further linear regression analysis revealed a negative relationship between exosomal SNHG6 and ESR (B = -0.384, P = 0.006), and a positive relationship between SNHG31 and ESR (B = 0.381, P = 0.007). Exosomal SNHG6 also showed a negative relationship with CRP (B = -0.361, P = 0.019). Moreover, exosomal RPS18P9 and SNGH31 had a negative effect and a positive effect on DAS28, respectively (B = -0.463, P < 0.001; B = 0.586, P < 0.001), implying novel exosomal lncRNAs were the independent influencing factors of the main RA-related clinical indices.

CONCLUSIONS

lncRNAs in RA plasma exosomes have characteristic expression profiles, including some lncRNAs with potential as diagnostic biomarkers and therapeutic targets for RA.

Immunoregulatory Roles of Osteopontin in Diseases

Osteopontin (OPN) is a multifunctional protein that plays a pivotal role in the immune system. It is involved in various biological processes, including cell adhesion, migration and survival. The study of the immunomodulatory effects of OPN is of paramount importance due to its potential therapeutic applications. A comprehensive understanding of how OPN regulates the immune response could pave the way for the development of novel treatments for a multitude of diseases, including autoimmune disorders, infectious diseases and cancer. Therefore, in the following paper, we provide a systematic overview of OPN and its immunoregulatory roles in various diseases, laying the foundation for the development of OPN-based therapies in the future.

Differential Expression Profiles of Plasma Exosomal microRNAs in Rheumatoid Arthritis

Aim

Differential expression maps of microRNAs (miRNAs) are connected to the autoimmune diseases. This study sought to elucidate the expression maps of exosomal miRNA in plasma of rheumatoid arthritis (RA) patients and their potential clinical significance.

Methods

In the screening phase, small RNA sequencing was performed to characterize dysregulated exosome-derived miRNAs in the plasma samples from six patients with RA and six healthy patients. At the independent verification stage, the candidate plasma exosomal miRNAs were verified in 40 patients with RA and 32 healthy patients by using qRT-PCR. The correlation of miRNA levels and clinical characteristics was tested in patients with RA. The value of these miRNAs in diagnosing RA was assessed with the receiver operating characteristic curve.

Results

During the screening phase, 177 and 129 miRNAs were increased and decreased in RA patients and healthy controls, respectively. There were 10 candidate plasma exosomal miRNAs selected for the next identification. Compared with the healthy controls, eight plasma exosomal miRNAs (let-7a-5p, let-7b-5p, let-7d-5p, let-7f-5p, let-7g-5p, let-7i-5p, miR-128-3p, and miR-25-3p) were significantly elevated in RA patients, but miR-144-3p and miR-15a-5p expression exhibited no significant changes. The let-7a-5p and miR-25-3p levels were linked to the rheumatoid factor-positive phenotype in RA patients. For the eight miRNAs, the area under the subject work characteristic curve (AUC) is 0.641 to 0.843, and their combination had a high diagnostic accuracy for RA (AUC = 0.916).

Conclusion

Our study illustrates that novel exosomal miRNAs in the plasma may represent potential noninvasive biomarkers for RA.

Exosomes as Rheumatoid Arthritis Diagnostic Biomarkers and Therapeutic Agents

Rheumatoid arthritis (RA) is a chronic inflammatory joint disorder that causes systemic inflammation, autoimmunity, and joint abnormalities that result in permanent disability. Exosomes are nanosized extracellular particles found in mammals (40–100 nm). They are a transporter of lipids, proteins, and genetic material involved in mammalian cell–cell signaling, biological processes, and cell signaling. Exosomes have been identified as playing a role in rheumatoid arthritis-related joint inflammation (RA). Uniquely functioning extracellular vesicles (EVs) are responsible for the transport of autoantigens and mediators between distant cells. In addition, paracrine factors, such as exosomes, modulate the immunomodulatory function of mesenchymal stem cells (MSCs). In addition to transporting genetic information, exosomes convey miRNAs between cells and have been studied as drug delivery vehicles. In animal models, it has been observed that MSCs secrete EVs with immunomodulatory properties, and promising results have been observed in this area. By understanding the diversity of exosomal contents and their corresponding targets, it may be possible to diagnose autoimmune diseases. Exosomes can be employed as diagnostic biomarkers for immunological disorders. We here discuss the most recent findings regarding the diagnostic, prognostic, and therapeutic potential of these nanoparticles in rheumatoid arthritis and provide an overview of the evidence pertaining to the biology of exosomes in RA.

The novel delivery-exosome application for diagnosis and treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic degenerative disease characterized by persistent systemic synovitis, with a high risk of stiffness, pain, and swelling. It may affect the other extra-articular tissues. There is no ideal treatment for this disease at present, and it can only be controlled by medication to alleviate the prognosis. Exosomes are small vesicles secreted by various cells in the organism under normal or pathological conditions, and play a role in immune response, antigen presentation, cell migration, cell differentiation, tumor invasion and so on. Due to the adverse effects of conventional drugs and treatments in the treatment of RA, exosomes, as a nanocarrier with many advantages, can have a great impact on the loading of drugs for the treatment of RA. This article reviews the role of exosomes in the pathogenesis of RA and the progress of exosome-based therapy for RA.

Vesicular traffic-mediated cell-to-cell signaling at the immune synapse in Ankylosing Spondylitis

The chronic inflammatory disease ankylosing spondylitis (AS) is marked by back discomfort, spinal ankylosis, and extra-articular symptoms. In AS, inflammation is responsible for both pain and spinal ankylosis. However, the processes that sustain chronic inflammation remain unknown. Despite the years of research conducted to decipher the intricacy of AS, little progress has been made in identifying the signaling events that lead to the development of this disease. T cells, an immune cell type that initiates and regulates the body's response to infection, have been established to substantially impact the development of AS. T lymphocytes are regarded as a crucial part of adaptive immunity for the control of the immune system. A highly coordinated interaction involving antigen-presenting cells (APCs) and T cells that regulate T cell activation constitutes an immunological synapse (IS). This first phase leads to the controlled trafficking of receptors and signaling mediators involved in folding endosomes to the cellular interface, which allows the transfer of information from T cells to APCs through IS formation. Discrimination of self and nonself antigen is somatically learned in adaptive immunity. In an autoimmune condition such as AS, there is a disturbance of self/nonself antigen discrimination; available findings imply that the IS plays a preeminent role in the adaptive immune response. In this paper, we provide insights into the genesis of AS by evaluating recent developments in the function of vesicular trafficking in IS formation and the targeted release of exosomes enriched microRNAs (miRNA) at the synaptic region in T cells.

Exosomal long non-coding RNA TRAFD1-4:1 derived from fibroblast-like synoviocytes suppresses chondrocyte proliferation and migration by degrading cartilage extracellular matrix in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, autoimmune and systemic inflammatory disease affecting 1% of the population worldwide. Immune suppression of the activity and progress of RA is vital to reduce the disability and mortality rate as well as improve the quality of life of RA patients. However, the immune molecular mechanism of RA has not been clarified yet. Our results indicated that exosomes derived from TNFα-stimulated RA fibroblast-like synoviocytes (RA-FLSs) suppressed chondrocyte proliferation and migration through modulating cartilage extracellular matrix (CECM) determining by MTS assay, cell cycle analysis, Transwell assay and Western blot (WB). Besides, RNA sequencing and verification by qRT-PCR revealed that exosomal long non-coding RNA (lncRNA) tumor necrosis factor-associated factor 1 (TRAF1)-4:1 derived from RA-FLSs treated with TNFα was a candidate lncRNA, which also inhibited chondrocyte proliferation and migration through degrading CECM. Moreover, RNA sequencing and bioinformatics analysis identified that C-X-C motif chemokine ligand 1 (CXCL1) was a target mRNA of miR-27a-3p while miR-27a-3p was a target miRNA of lnc-TRAF1-4:1 in chondrocytes. Mechanistically, lnc-TRAF1-4:1 upregulated CXCL1 expression through sponging miR-27a-3p as a competing endogenous RNA (ceRNA) in chondrocytes identifying by Dual-luciferase reporter gene assay. Summarily, exosomal lncRNA TRAFD1-4:1 derived from RA-FLSs suppressed chondrocyte proliferation and migration through degrading CECM by upregulating CXCL1 as a sponge of miR-27a-3p. This study uncovered a novel RA-related lncRNA and investigated the roles of RA-FLS-derived exosomes and exosomal lnc-TRAF1-4:1 in articular cartilage impairment, which might provide novel therapeutic targets for RA.

The role and therapeutic applications of exosomes in multiple sclerosis disease

A range of the central nervous system (CNS) and immune cells are affected by multiple sclerosis (MS), a complex autoimmune disease of the CNS. Chronic neuroinflammation, demyelination, and neuronal death are all features of MS, but the disease's molecular mechanisms are unknown. Exosomes are small, membrane-bound extracellular vesicles with a crucial role in cell communication. They are stable in biological fluids and emerge from the cell membrane during endocytic internalization. It might be possible to recognize better the mechanisms involved in the development and progress of illnesses by understanding the variety of exosomal contents and their associated targets, like neurologic disorders. In this review, we sought to bring together important data on the biology of exosomes in MS and highlight discoveries on these nanoparticles' prognostic, diagnostic and therapeutic potential.

Colorectal cancer-derived exosomes and modulation KRAS signaling

Colorectal cancer (CRC) is one of the most common cancers worldwide and one of the main causes of cancer-associated mortality. At the period of diagnosis, metastases to other tissues will be present in around 30% of CRC individuals. Individuals with CRC continue to have a poor prognosis despite advances in medication. There is a growing body of literature that CRC develops as a result of the aggregation of various mutations in tumor oncogenes or suppressor genes and that diagnosing cancer in its initial phases may assist in increasing the overall lifespan of individuals with the illness. On the other hand, tumor cells may discharge exosomes in response to oncogenic mutations. By Inhibiting signaling pathways, including the Kirsten rat sarcoma virus (KRAS) mechanism, which is important in a variety of cell activities, exosomes have been shown to cause colorectal cancer in animal studies. The purpose of this review was to summarize the latest discoveries on the modulation of KRAS signaling by exosomes extracted from colorectal cancer.

The roles and therapeutic approaches of MSC-derived exosomes in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in both men and women, accounting for 8% of all new cancer cases in both. CRC is typically diagnosed at advanced stages, which leads to a higher mortality rate. The 5-year survival rate for CRC is 64% in all cases and just 12% in metastatic cases. Mesenchymal stem cells (MSCs) are one of the most recent approaches for therapeutic interventions in cancer. MSCs have multiple properties, including paracrine signaling, immunologic functions, and the ability to migrate to the targeted tissue. MSCs can produce and secrete exosomes in tumor microenvironments. These exosomes can transfer compounds across tumor cells, stromal cells, fibroblasts, endothelial cells, and immune cells. Studies showed that modified MCS-derived exosomes have enhanced specificity, reduced immunogenicity, and better targeting capabilities in comparison to other frequently used delivery systems such as liposomes. Therefore, this study aimed to provide a comprehensive view of the role of natural MSC-derived exosomes in CRC, as well as the most current and prospective advancements in MSC-derived exosome therapeutic modifications.

Osteopontin in autoimmune disorders: current knowledge and future perspective

Osteopontin (OPN) is a multifunctional cytokine and adhesion molecule, as well as an unusual regulator for both innate and adaptive immune responses. Several immune cells can produce OPN, including dendritic cells (DCs), macrophages, and T lymphocytes. OPN expression is reported to be increased in a wide range of disorders, including autoimmunity, cancer, and allergy. The overexpression of OPN in several autoimmune disorders, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), Type 1 diabetes (T1D), inflammatory bowel disease (IBD), Sjögren's, and myasthenia gravis, have been shown to be correlated with disease severity. Regarding the important regulatory roles of OPN in the immune system, this study aimed to review the role of this molecule in autoimmune disorders and to provide a complete view of the current knowledge in this field.

Circulating extracellular vesicles and rheumatoid arthritis: a proteomic analysis

Circulating extracellular vesicles (EVs) are membrane-bound nanoparticles secreted by most cells for intracellular communication and transportation of biomolecules. EVs carry proteins, lipids, nucleic acids, and receptors that are involved in human physiology and pathology. EV cargo is variable and highly related to the type and state of the cellular origin. Three subtypes of EVs have been identified: exosomes, microvesicles, and apoptotic bodies. Exosomes are the smallest and the most well-studied class of EVs that regulate different biological processes and participate in several diseases, such as cancers and autoimmune diseases. Proteomic analysis of exosomes succeeded in profiling numerous types of proteins involved in disease development and prognosis. In rheumatoid arthritis (RA), exosomes revealed a potential function in joint inflammation. These EVs possess a unique function, as they can transfer specific autoantigens and mediators between distant cells. Current proteomic data demonstrated that exosomes could provide beneficial effects against autoimmunity and exert an immunosuppressive action, particularly in RA. Based on these observations, effective therapeutic strategies have been developed for arthritis and other inflammatory disorders.

Preparation of EGCG decorated, injectable extracellular vesicles for cartilage repair in rat arthritis

Arthritis is a kind of chronic inflammatory autoimmune disease, which can destroy joint cartilage and bone, leading to joint pain, joint swelling, and limited mobility. Traditional therapies have many side effects or focus too much on anti-inflammation while neglecting joint repair. In this experiment, we combined Epigallocatechin gallate (EGCG) with extracellular vesicles derived from macrophages to treat rheumatoid arthritis. Sustained-release resulted in a significant decrease in chondrocyte expression of hypoxia-inducible factor 1-alpha, a decrease in apoptosis-related proteins Cytochrome C, Caspase-3, Caspase-9, and Bax. Molecular biological analysis showed that extracellular vesicles-encapsulated EGCG (EVs-EGCG) more significantly upregulated type II collagen expression by about 1.8-fold than EGCG alone, which was more beneficial for arthritis repair. Animal experiments revealed that these EGCG-coated extracellular vesicles significantly reduced swelling, decreased synovial hyperplasia, repaired cartilage, and attenuated arthritis-related pathology scores in arthritic rats. Measurement data showed that EVs-EGCG treatment reduced joint swelling by approximately 39.5% in rheumatoid rats. In vitro studies have shown that this EVs-EGCG can increase the expression of cartilage type II collagen and reduce apoptosis of chondrocytes. Moreover, it was demonstrated in vivo experiments to reduce cartilage destruction in rheumatoid arthritis rats, providing a solution for the treatment of rheumatoid arthritis.

Advances in Biosensors Technology for Detection and Characterization of Extracellular Vesicles

Exosomes are extracellular vehicles (EVs) that encapsulate genomic and proteomic material from the cell of origin that can be used as biomarkers for non-invasive disease diagnostics in point of care settings. The efficient and accurate detection, quantification, and molecular profiling of exosomes are crucial for the accurate identification of disease biomarkers. Conventional isolation methods, while well-established, provide the co-purification of proteins and other types of EVs. Exosome purification, characterization, and OMICS analysis are performed separately, which increases the complexity, duration, and cost of the process. Due to these constraints, the point-of-care and personalized analysis of exosomes are limited in clinical settings. Lab-on-a-chip biosensing has enabled the integration of isolation and characterization processes in a single platform. The presented review discusses recent advancements in biosensing technology for the separation and detection of exosomes. Fluorescent, colorimetric, electrochemical, magnetic, and surface plasmon resonance technologies have been developed for the quantification of exosomes in biological fluids. Size-exclusion filtration, immunoaffinity, electroactive, and acoustic-fluid-based technologies were successfully applied for the on-chip isolation of exosomes. The advancement of biosensing technology for the detection of exosomes provides better sensitivity and a reduced signal-to-noise ratio. The key challenge for the integration of clinical settings remains the lack of capabilities for on-chip genomic and proteomic analysis.

Bone-a-Petite: Engineering Exosomes towards Bone, Osteochondral, and Cartilage Repair

Recovery from bone, osteochondral, and cartilage injuries/diseases has been burdensome owing to the damaged vasculature of large defects and/or avascular nature of cartilage leading to a lack of nutrients and supplying cells. However, traditional means of treatment such as microfractures and cell-based therapy only display limited efficacy due to the inability to ensure cell survival and potential aggravation of surrounding tissues. Exosomes have recently emerged as a powerful tool for this tissue repair with its complex content of transcription factors, proteins, and targeting ligands, as well as its unique ability to home in on target cells thanks to its phospholipidic nature. They are engineered to serve specialized applications including enhancing repair, anti-inflammation, regulating homeostasis, etc. via means of physical, chemical, and biological modulations in its deriving cell culture environments. This review focuses on the engineering means to functionalize exosomes for bone, osteochondral, and cartilage regeneration, with an emphasis on conditions such as osteoarthritis, osteoporosis, and osteonecrosis. Finally, future implications for exosome development will be given alongside its potential combination with other strategies to improve its therapeutic efficacy in the osteochondral niche.

Exosomes as Drug Delivery Systems: Endogenous Nanovehicles for Treatment of Systemic Lupus Erythematosus

Exosomes, nanometer-sized lipid-bilayer-enclosed extracellular vesicles (EVs), have attracted increasing attention due to their inherent ability to shuttle proteins, lipids and genes between cells and their natural affinity to target cells. Their intrinsic features such as stability, biocompatibility, low immunogenicity and ability to overcome biological barriers, have prompted interest in using exosomes as drug delivery vehicles, especially for gene therapy. Evidence indicates that exosomes play roles in both immune stimulation and tolerance, regulating immune signaling and inflammation. To date, exosome-based nanocarriers delivering small molecule drugs have been developed to treat many prevalent autoimmune diseases. This review highlights the key features of exosomes as drug delivery vehicles, such as therapeutic cargo, use of targeting peptide, loading method and administration route with a broad focus. In addition, we outline the current state of evidence in the field of exosome-based drug delivery systems in systemic lupus erythematosus (SLE), evaluating exosomes derived from various cell types and engineered exosomes.