Functional Flexibility of Exosomes and MicroRNAs of Intestinal Epithelial Cells in Affecting Inflammation

Peroxiredoxin 3 Deficiency Exacerbates DSS-Induced Acute Colitis via Exosomal miR-1260b-Mediated Barrier Disruption and Proinflammatory Signaling

Aims: Peroxiredoxin3 (Prdx3) is an intracellular antioxidant enzyme that is specifically localized in mitochondria and protects against oxidative stress by removing mitochondrial reactive oxygen species (ROS). The intestinal epithelium provides a physical and biochemical barrier that segregates host tissues from commensal bacteria to maintain intestinal homeostasis. An imbalance between the cellular antioxidant defense system and oxidative stress has been implicated in the pathogenesis of inflammatory bowel disease (IBD). However, the role of Prdx3 in the intestinal epithelium under intestinal inflammation has not been elucidated. To investigate the potential role of Prdx3 in intestinal inflammation, we used intestinal epithelial cell (IEC)-specific Prdx3-knockout mice. Results: IEC-specific Prdx3-deficient mice showed more severe colitis phenotypes with greater degrees of body weight loss, colon shortening, barrier disruption, mitochondrial damage, and ROS generation in IECs. Furthermore, exosomal miR-1260b was dramatically increased in Prdx3-knockdown colonic epithelial cells. Mechanistically, Prdx3 deficiency promoted intestinal barrier disruption and inflammation via P38-mitogen-activated protein kinase/NFκB signaling. Innovation: This is the first study to report the protective role of Prdx3 in acute colitis using IEC-specific conditional knockout mice. Conclusion: Our study sheds light on the role of exosome-loaded miRNAs, particularly miR-1260b, in IBD. Targeting miR-1260b or modulating exosome-mediated intercellular communication may hold promise as potential therapeutic strategies for managing IBD and restoring intestinal barrier integrity.

Immunological Regulation of Gut-Tropic Immune Cells by Extracellular Vesicles

The remarkable diversity of lymphocytes, essential components of the immune system, serves as an ingenious mechanism for maximizing the efficient utilization of limited host defense resources. While cell adhesion molecules, notably in gut-tropic T cells, play a central role in this mechanism, the counterbalancing molecular details have remained elusive. Conversely, we've uncovered the molecular pathways enabling extracellular vesicles secreted by lymphocytes to reach the gut's mucosal tissues, facilitating immunological regulation. This discovery sheds light on immune fine-tuning, offering insights into immune regulation mechanisms.

Exosome-mediated macrophage regulation for inflammatory bowel disease repair: a potential target of gut inflammation

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), is a complex condition without a definite cause. During IBD, immune cells such as macrophages release proinflammatory cytokines and chemokines, contributing to intestinal barrier integrity dysfunction. IBD is largely influenced by macrophages, which are classified into subtypes M1 and M2. M1 macrophages have been found to contribute to the development of IBD, whereas M2 macrophages alleviate IBD. Hence, agents that cause increased polarization of the M2 phenotype could help repair IBD. Exosomes, as ubiquitous conveyors of intercellular messages, are involved in immune responses and immune-mediated disease processes. Exosomes and their microRNA (miRNA) from healthy cells have been found to polarize macrophages to M2 to repair IBD due to their anti-inflammatory properties; however, those from inflammatory-driven cells and disease cells promote M1 macrophages to perpetuate IBD. Here, we review the biogenesis, biochemical composition, and sources of exosomes, as well as the roles of exosomes as extracellular vesicles in regulation of macrophages to repair IBD.

Emodin Ameliorates Severe Acute Pancreatitis-Associated Acute Lung Injury in Rats by Modulating Exosome-Specific miRNA Expression Profiles

Background

Numerous preclinical investigations have exhibited the beneficial impact of emodin (EMO) on the management of severe acute pancreatitis (SAP)-associated acute lung injury (ALI). However, the potential of EMO to mitigate organ damage through the modulation of exosome (Exo)-specific miRNA expression profiles remains unclear.

Methods

The SAP rat model was established by retrograde injection of 5% sodium taurocholate into the pancreatic bile duct. Rats received intragastric administration of EMO at 2 h and 12 h post-modeling. Plasma and bronchoalveolar lavage fluid (BALF)-derived exosomes were isolated and purified from SAP rats treated with EMO. The therapeutic effects of these Exos in SAP rats were assessed using hematoxylin-eosin staining and measurement of inflammatory factor levels. MicroRNA (miRNA) sequencing was conducted on plasma and BALF-derived Exos, and rescue experiments were performed to investigate the function of NOVEL miR-29a-3p in the treatment of SAP using EMO.

Results

EMO exhibits ameliorative effects on pancreatic and lung injury and inflammation in rats with SAP. Plasma/BALF-derived Exos from EMO-treated SAP rats also have therapeutic effects on SAP rats. The miRNA expression profile of plasma and BALF-derived Exos in SAP rats underwent significant changes upon exposure to EMO. In particular, 34 differentially expressed miRNAs (DEmiRNAs) were identified when comparing BALF-SAP+EMO-Exo and BALF-SAP-Exo. 39 DEmiRNAs were identified when comparing plasma-SAP+EMO-Exo to plasma-SAP-Exo. We found that SAP rats treated with Exos derived from BALF exhibited a more potent therapeutic response than those treated with Exos derived from plasma. EMO may rely on NOVEL-rno-miR-29a-3p expression to prevent pulmonary injury in SAP rats.

Conclusion

The mechanism of action of EMO is observed to have a significant impact on the miRNA expression profile of Exos derived from plasma and BALF in SAP rats. NOVEL-rno-miR-29a-3p, which is specific to Exos, and is derived from BALF, may play a crucial role in the therapeutic efficacy of EMO.

Proinflammatory Bone Marrow Mesenchymal Stem Cell-Derived Exosomal miR-150-3p Suppresses Proinflammatory Polarization of Alveolar Macrophages in Sepsis by Targeting Inhibin Subunit Beta A

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes can protect lung tissues against sepsis, but its related mechanism remains elusive. BMSCs were primed with or without lipopolysaccharide (LPS) before extracting exosomes. The isolated exosomes were identified by transmission electron microscopy, nanoparticle tracking analysis, and western blot. LPS-stimulated macrophages were cocultured with exosomes for 24 h, followed by enzyme-linked immunosorbent assay, flow cytometry, and molecular experiments. Bioinformatics and luciferase assay were employed to investigate the interaction between miR-150-3p and inhibin subunit beta A (INHBA). MiR-150-3p expression was increased in exosomes in a proinflammatory environment. Exosomes suppressed proinflammatory polarization by downregulating IL-6, IL-1β, iNOS, and CD86, as well as promoted anti-inflammatory polarization by upregulating IL-10, ARG-1, and CD206 in LPS-stimulated macrophages. Such effects were more pronounced by LPS-primed exosomes, which was reversed in the absence of miR-150-3p. MiR-150-3p targeted INHBA. INHBA silencing decreased CD86 expression and increased CD206 expression in macrophages, but these effects were reversed by exosomal miR-150-3p inhibition. Proinflammatory BMSC-derived exosomal miR-150-3p suppressed proinflammatory polarization and promoted anti-inflammatory polarization of alveolar macrophages to attenuate LPS-induced sepsis by targeting INHBA.

Unraveling the Intricate Roles of Exosomes in Cardiovascular Diseases: A Comprehensive Review of Physiological Significance and Pathological Implications

Exosomes, as potent intercellular communication tools, have garnered significant attention due to their unique cargo-carrying capabilities, which enable them to influence diverse physiological and pathological functions. Extensive research has illuminated the biogenesis, secretion, and functions of exosomes. These vesicles are secreted by cells in different states, exerting either protective or harmful biological functions. Emerging evidence highlights their role in cardiovascular disease (CVD) by mediating comprehensive interactions among diverse cell types. This review delves into the significant impacts of exosomes on CVD under stress and disease conditions, including coronary artery disease (CAD), myocardial infarction, heart failure, and other cardiomyopathies. Focusing on the cellular signaling and mechanisms, we explore how exosomes mediate multifaceted interactions, particularly contributing to endothelial dysfunction, oxidative stress, and apoptosis in CVD pathogenesis. Additionally, exosomes show great promise as biomarkers, reflecting differential expressions of NcRNAs (miRNAs, lncRNAs, and circRNAs), and as therapeutic carriers for targeted CVD treatment. However, the specific regulatory mechanisms governing exosomes in CVD remain incomplete, necessitating further exploration of their characteristics and roles in various CVD-related contexts. This comprehensive review aims to provide novel insights into the biological implications of exosomes in CVD and offer innovative perspectives on the diagnosis and treatment of CVD.

MicroRNA Profiles in Intestinal Epithelial Cells in a Mouse Model of Sepsis

Sepsis is a systemic inflammatory disorder that leads to the dysfunction of multiple organs. In the intestine, the deregulation of the epithelial barrier contributes to the development of sepsis by triggering continuous exposure to harmful factors. However, sepsis-induced epigenetic changes in gene-regulation networks within intestinal epithelial cells (IECs) remain unexplored. In this study, we analyzed the expression profile of microRNAs (miRNAs) in IECs isolated from a mouse model of sepsis generated via cecal slurry injection. Among 239 miRNAs, 14 miRNAs were upregulated, and 9 miRNAs were downregulated in the IECs by sepsis. Upregulated miRNAs in IECs from septic mice, particularly miR-149-5p, miR-466q, miR-495, and miR-511-3p, were seen to exhibit complex and global effects on gene regulation networks. Interestingly, miR-511-3p has emerged as a diagnostic marker in this sepsis model due to its increase in blood in addition to IECs. As expected, mRNAs in the IECs were remarkably altered by sepsis; specifically, 2248 mRNAs were decreased, while 612 mRNAs were increased. This quantitative bias may be possibly derived, at least partly, from the direct effects of the sepsis-increased miRNAs on the comprehensive expression of mRNAs. Thus, current in silico data indicate that there are dynamic regulatory responses of miRNAs to sepsis in IECs. In addition, the miRNAs that were increased with sepsis had enriched downstream pathways including Wnt signaling, which is associated with wound healing, and FGF/FGFR signaling, which has been linked to chronic inflammation and fibrosis. These modifications in miRNA networks in IECs may lead to both pro- and anti-inflammatory effects in sepsis. The four miRNAs discovered above were shown to putatively target LOX, PTCH1, COL22A1, FOXO1, or HMGA2, via in silico analysis, which were associated with Wnt or inflammatory pathways and selected for further study. The expressions of these target genes were downregulated in sepsis IECs, possibly through posttranscriptional modifications of these miRNAs. Taken together, our study suggests that IECs display a distinctive miRNA profile which is capable of comprehensively and functionally reshaping the IEC-specific mRNA landscape in a sepsis model.

Fighting Fire with Fire: Exosomes and Acute Pancreatitis-Associated Acute Lung Injury

Acute pancreatitis (AP) is a prevalent clinical condition of the digestive system, with a growing frequency each year. Approximately 20% of patients suffer from severe acute pancreatitis (SAP) with local consequences and multi-organ failure, putting a significant strain on patients' health insurance. According to reports, the lungs are particularly susceptible to SAP. Acute respiratory distress syndrome, a severe type of acute lung injury (ALI), is the primary cause of mortality among AP patients. Controlling the mortality associated with SAP requires an understanding of the etiology of AP-associated ALI, the discovery of biomarkers for the early detection of ALI, and the identification of potentially effective drug treatments. Exosomes are a class of extracellular vesicles with a diameter of 30-150 nm that are actively released into tissue fluids to mediate biological functions. Exosomes are laden with bioactive cargo, such as lipids, proteins, DNA, and RNA. During the initial stages of AP, acinar cell-derived exosomes suppress forkhead box protein O1 expression, resulting in M1 macrophage polarization. Similarly, macrophage-derived exosomes activate inflammatory pathways within endothelium or epithelial cells, promoting an inflammatory cascade response. On the other hand, a part of exosome cargo performs tissue repair and anti-inflammatory actions and inhibits the cytokine storm during AP. Other reviews have detailed the function of exosomes in the development of AP, chronic pancreatitis, and autoimmune pancreatitis. The discoveries involving exosomes at the intersection of AP and acute lung injury (ALI) are reviewed here. Furthermore, we discuss the therapeutic potential of exosomes in AP and associated ALI. With the continuous improvement of technological tools, the research on exosomes has gradually shifted from basic to clinical applications. Several exosome-specific non-coding RNAs and proteins can be used as novel molecular markers to assist in the diagnosis and prognosis of AP and associated ALI.