Macrophages exposed to HIV viral protein disrupt lung epithelial cell integrity and mitochondrial bioenergetics via exosomal microRNA shuttling

The calcineurin-NFATc pathway modulates the lipid mediators in BAL fluid extracellular vesicles, thereby regulating microvascular endothelial cell barrier function

Extracellular vesicles mediate intercellular communication by transporting biologically active macromolecules. Our prior studies have demonstrated that the nuclear factor of activated T cell cytoplasmic member 3 (NFATc3) is activated in mouse pulmonary macrophages in response to lipopolysaccharide (LPS). Inhibition of NFATc3 activation by a novel cell-permeable calcineurin peptide inhibitor CNI103 mitigated the development of acute lung injury (ALI) in LPS-treated mice. Although pro-inflammatory lipid mediators are known contributors to lung inflammation and injury, it remains unclear whether the calcineurin-NFATc pathway regulates extracellular vesicle (EV) lipid content and if this content contributes to ALI pathogenesis. In this study, EVs from mouse bronchoalveolar lavage fluid (BALF) were analyzed for their lipid mediators by liquid chromatography in conjunction with mass spectrometry (LC-MS/MS). Our data demonstrate that EVs from LPS-treated mice contained significantly higher levels of arachidonic acid (AA) metabolites, which were found in low levels by prior treatment with CNI103. The catalytic activity of lung tissue cytoplasmic phospholipase A2 (cPLA2) increased during ALI, correlating with an increased amount of arachidonic acid (AA) in the EVs. Furthermore, ALI is associated with increased expression of cPLA2, cyclooxygenase 2 (COX2), and lipoxygenases (5-LOX, 12-LOX, and 15-LOX) in lung tissue, and pretreatment with CNI103 inhibited the catalytic activity of cPLA2 and the expression of cPLA2, COX, and LOX transcripts. Furthermore, co-culture of mouse pulmonary microvascular endothelial cell (PMVEC) monolayer and NFAT-luciferase reporter macrophages with BALF EVs from LPS-treated mice increased the pulmonary microvascular endothelial cell (PMVEC) monolayer barrier permeability and luciferase activity in macrophages. However, EVs from CNI103-treated mice had no negative impact on PMVEC monolayer barrier integrity. In summary, BALF EVs from LPS-treated mice carry biologically active NFATc-dependent, AA-derived lipids that play a role in regulating PMVEC monolayer barrier function.

The Role of MicroRNAs in HIV Infection

MicroRNAs (miRNAs), a class of small, non-coding RNAs, play a pivotal role in regulating gene expression at the post-transcriptional level. These regulatory molecules are integral to many biological processes and have been implicated in the pathogenesis of various diseases, including Human Immunodeficiency Virus (HIV) infection. This review aims to cover the current understanding of the multifaceted roles miRNAs assume in the context of HIV infection and pathogenesis. The discourse is structured around three primary focal points: (i) elucidation of the mechanisms through which miRNAs regulate HIV replication, encompassing both direct targeting of viral transcripts and indirect modulation of host factors critical for viral replication; (ii) examination of the modulation of miRNA expression by HIV, mediated through either viral proteins or the activation of cellular pathways consequent to viral infection; and (iii) assessment of the impact of miRNAs on the immune response and the progression of disease in HIV-infected individuals. Further, this review delves into the potential utility of miRNAs as biomarkers and therapeutic agents in HIV infection, underscoring the challenges and prospects inherent to this line of inquiry. The synthesis of current evidence positions miRNAs as significant modulators of the host-virus interplay, offering promising avenues for enhancing the diagnosis, treatment, and prevention of HIV infection.

The extracellular vesicles in HIV infection and progression: mechanisms, and theranostic implications

Extracellular vesicles (EVs), these minute yet mighty cellular messengers are redefining our understanding of a spectrum of diseases, from cancer to cardiovascular ailments, neurodegenerative disorders, and even infectious diseases like HIV. Central to cellular communication, EVs emerge as both potent facilitators and insightful biomarkers in immune response and the trajectory of disease progression. This review ventures deep into the realm of EVs in HIV-unraveling their pivotal roles in diagnosis, disease mechanism unravelling, and therapeutic innovation. With a focus on HIV, we will highlights the transformative potential of EVs in both diagnosing and treating this formidable virus. Unveiling the intricate dance between EVs and HIV, the review aims to shed light on novel therapeutic strategies that could significantly benefit HIV therapy, potentially even leading to the eradication of HIV.

Lactobacillus plantarum 45 activates SHP2 through inhibition of oxidative stress to regulate osteoblast and osteoclast differentiation

BACKGROUND

The purpose of this study is to observe LP45 (Lactobacillus plantarum 45) to investigate the mechanism by which LP45 attenuates oxidative stress-induced damage and regulates the osteoblast-osteoclast balance.

MATERIALS AND METHODS

The oxidative stress level and osteoblast- and osteoclast-related proteins were detected by immunofluorescence staining, Western blotting, ROS fluorescent probe and ELISA. Osteoblast cell proliferation capacity was determined by the CCK-8 assay. X-ray observation and HE staining were used to detect the effect of LP45 on osteoporosis.

RESULTS

The expression level of SHP2 and Src was significantly increased, and the expression levels of NOX4, P22, P47, IL-1β, NLRP3, IRF3, RANK, β-catenin and INF-β were inhibited in LP45 group and LPS + LP45 group as compared to those in LPS group. Compared with that in LPS group, the concentration of SOD was increased and the concentration of MDA was decreased in LPS + LP45 group. The protein expressions of OPG, RANKL, RUNX3, RANK and β-catenin in LP45 group and LPS + LP45 group increased. The protein expressions of NF-κB, CREB and AP-1 in LP45 group and LPS + LP45 group decreased significantly. The results were also confirmed by immunofluorescence staining and ROS fluorescent probe. X-ray observation and HE staining showed that LP45 could inhibit the progression of osteoporosis.

CONCLUSION

LP45 can exert its antioxidant effect by inhibiting the production of oxidative stress to activate the SHP2 signaling pathway, thus promoting osteoblast differentiation and repressing osteoclast formation to maintain bone homeostasis and improve bone metabolism.

A review on separation and application of plant-derived exosome-like nanoparticles

Exosomes-like nanoparticles (ELNs) (exosomes or extracellular vesicles) are vesicle-like bodies secreted by cells. Plant ELNs (PENs) are membrane vesicles secreted by plant cells, with a lipid bilayer as the basic skeleton, enclosing various active substances such as proteins and nucleic acids, which have many physiological and pathological functions. Recent studies have found that the PENs are widespread within different plant species and their biological functions are increasingly recognized. The effective separation method is also necessary for its function and application. Ultracentrifugation, sucrose density gradient ultracentrifugation, ultrafiltration, polymer-based precipitation methods, etc., are commonly used methods for plant exosome-like nanoparticle extraction. In recent years, emerging methods such as size exclusion chromatography, immunoaffinity capture-based technique, and microfluidic technology have shown advancements compared to traditional methods. The standardized separation process for PENs continues to evolve. In this review, we summarized the recent progress in the biogenesis, components, separation methods, and some functions of PENs. When the research on the separation method of PENs and their unique biological structure is further studied. A brand-new idea for the efficient separation and utilization of PENs can be provided in the future, which has a very broad prospect.

HIV-1 Myeloid Reservoirs - Contributors to Viral Persistence and Pathogenesis

PURPOSE OF REVIEW

HIV reservoirs are the main barrier to cure. CD4+ T cells have been extensively studied as the primary HIV-1 reservoir. However, there is substantial evidence that HIV-1-infected myeloid cells (monocytes/macrophages) also contribute to viral persistence and pathogenesis.

RECENT FINDINGS

Recent studies in animal models and people with HIV-1 demonstrate that myeloid cells are cellular reservoirs of HIV-1. HIV-1 genomes and viral RNA have been reported in circulating monocytes and tissue-resident macrophages from the brain, urethra, gut, liver, and spleen. Importantly, viral outgrowth assays have quantified persistent infectious virus from monocyte-derived macrophages and tissue-resident macrophages. The myeloid cell compartment represents an important target of HIV-1 infection. While myeloid reservoirs may be more difficult to measure than CD4+ T cell reservoirs, they are long-lived, contribute to viral persistence, and, unless specifically targeted, will prevent an HIV-1 cure.

Crosstalk between autophagy and inflammasomes in ricin-induced inflammatory injury

Ricin (ricin toxin, RT) has the potential to cause damage to multiple organs and systems. Currently, there are no existing antidotes, vaccinations, or effective therapies to prevent or treat RT intoxication. Apart from halting protein synthesis, RT also induces oxidative stress, inflammation and autophagy. To explore the mechanisms of RT-induced inflammatory injury and specific targets of prevention and treatment for RT poisoning, we characterized the role of cross-talk between autophagy and NLRP3 inflammasome in RT-induced damage and elucidated the underlying mechanisms. We showed that RT-induced inflammation was attributed to activation of the TLR4/MyD88/NLRP3 signaling and ROS production, evidenced by increased ASC speck formation and attenuated TXNIP/TRX-1 interaction, as well as pre-treatment with MCC950, MyD88 knockdown and NAC significantly reduced IL-1β, IL-6 and TNF-α mRNA expression. In addition, autophagy is also enhanced in RT-triggered MLE-12 cells. RT elevated the levels of ATG5, p62 and Beclin1 protein, provoked the accumulation of LC3 puncta detected by immunofluorescence staining. Treatment with rapamycin (Rapa) reversed the RT-caused TLR4/MyD88/NLRP3 signaling activation, ASC specks formation as well as the levels of IL-1β, IL-6 and TNF-α mRNA. In conclusion, RT promoted NLRP3 inflammasome activation and autophgay. Inflammation induced by RT was attenuated by autophagy activation, which suppressed the NLRP3 inflammasome. These findings suggest Rapa as a potential therapeutic drug for the treatment of RT-induced inflammation-related diseases.

Epigenetic modification: A novel insight into diabetic wound healing

Wound healing is an intricate and fine regulatory process. In diabetic patients, advanced glycation end products (AGEs), excessive reactive oxygen species (ROS), biofilm formation, persistent inflammation, and angiogenesis regression contribute to delayed wound healing. Epigenetics, the fast-moving science in the 21st century, has been up to date and associated with diabetic wound repair. In this review, we go over the functions of epigenetics in diabetic wound repair in retrospect, covering transcriptional and posttranscriptional regulation. Among these, we found that histone modification is widely involved in inflammation and angiogenesis by affecting macrophages and endothelial cells. DNA methylation is involved in factors regulation in wound repair but also affects the differentiation phenotype of cells in hyperglycemia. In addition, noncodingRNA regulation and RNA modification in diabetic wound repair were also generalized. The future prospects for epigenetic applications are discussed in the end. In conclusion, the study suggests that epigenetics is an integral regulatory mechanism in diabetic wound healing.

Naringenin regulates cigarette smoke extract-induced extracellular vesicles from alveolar macrophage to attenuate the mouse lung epithelial ferroptosis through activating EV miR-23a-3p/ACSL4 axis

BACKGROUND

Alveolar macrophages are one of the momentous regulators in pulmonary inflammatory responses, which can secrete extracellular vesicles (EVs) packing miRNAs. Ferroptosis, an iron-dependent cell death, is associated with cigarette smoke-induced lung injury, and EVs have been reported to regulate ferroptosis by transporting intracellular iron. However, the regulatory mechanism of alveolar macrophage-derived EVs has not been clearly illuminated in smoking-related pulmonary ferroptosis. Despite the known anti-ferroptosis effects of naringenin in lung injury, whether naringenin controls EVs-mediated ferroptosis has not yet been explored.

PURPOSE

We explore the effects of EVs from cigarette smoke-stimulated alveolar macrophages in lung epithelial ferroptosis, and elucidate the EV miRNA-mediated pharmacological mechanism of naringenin.

STUDY DESIGN AND METHODS

Differential and ultracentrifugation were conducted to extract EVs from different alveolar macrophages treatment groups in vitro. Both intratracheal instilled mice and treated epithelial cells were used to investigate the roles of EVs from alveolar macrophages involved in ferroptosis. Small RNA sequencing analysis was performed to distinguish altered miRNAs in EVs. The ferroptotic effects of EV miRNAs were examined by applying dual-Luciferase reporter assay and miRNA inhibitor transfection experiment.

RESULTS

Here, we firstly reported that EVs from cigarette smoke extract-induced alveolar macrophages (CSE-EVs) provoked pulmonary epithelial ferroptosis. The ferroptosis inhibitor ferrostatin-1 treatment reversed these changes in vitro. Moreover, EVs from naringenin and CSE co-treated alveolar macrophages (CSE+Naringenin-EVs) markedly attenuated the lung epithelial ferroptosis compared with CSE-EVs. Notably, we identified miR-23a-3p as the most dramatically changed miRNA among Normal-EVs, CSE-EVs, and CSE+Naringenin-EVs. Further experimental investigation showed that ACSL4, a pro-ferroptotic gene leading to lipid peroxidation, was negatively regulated by miR-23a-3p. The inhibition of miR-23a-3p diminished the efficacy of CSE+Naringenin-EVs.

CONCLUSION

Our findings firstly provided evidence that naringenin elevated the EV miR-23a-3p level from CSE-induced alveolar macrophages, thereby inhibiting the mouse lung epithelial ferroptosis via targeting ACSL4, and further complemented the mechanism of cigarette-induced lung injury and the protection of naringenin in a paracrine manner. The administration of miR-23a-3p-enriched EVs has the potential to ameliorate pulmonary ferroptosis.

Small extracellular vesicles-mediated cellular interactions between tumor cells and tumor-associated macrophages: Implication for immunotherapy

The tumor microenvironment consists of cancer cells and various stromal cells, including macrophages, which exhibit diverse phenotypes with either pro-inflammatory (M1) or anti-inflammatory (M2) effects. The interaction between cancer cells and macrophages plays a crucial role in tumor progression. Small extracellular vesicles (sEVs), which facilitate intercellular communication, are known to play a vital role in this process. This review provides a comprehensive summary of how sEVs derived from cancer cells, containing miRNAs, lncRNAs, proteins, and lipids, can influence macrophage polarization. Additionally, we discuss the impact of macrophage-secreted sEVs on tumor malignant transformation, including effects on proliferation, metastasis, angiogenesis, chemoresistance, and immune escape. Furthermore, we address the therapeutic advancements and current challenges associated with macrophage-associated sEVs, along with potential solutions.

Small RNA-big impact: exosomal miRNAs in mitochondrial dysfunction in various diseases

Mitochondria are multitasking organelles involved in maintaining the cell homoeostasis. Beyond its well-established role in cellular bioenergetics, mitochondria also function as signal organelles to propagate various cellular outcomes. However, mitochondria have a self-destructive arsenal of factors driving the development of diseases caused by mitochondrial dysfunction. Extracellular vesicles (EVs), a heterogeneous group of membranous nano-sized vesicles, are present in a variety of bodily fluids. EVs serve as mediators for intercellular interaction. Exosomes are a class of small EVs (30-100 nm) released by most cells. Exosomes carry various cargo including microRNAs (miRNAs), a class of short noncoding RNAs. Recent studies have closely associated exosomal miRNAs with various human diseases, including diseases caused by mitochondrial dysfunction, which are a group of complex multifactorial diseases and have not been comprehensively described. In this review, we first briefly introduce the characteristics of EVs. Then, we focus on possible mechanisms regarding exosome-mitochondria interaction through integrating signalling networks. Moreover, we summarize recent advances in the knowledge of the role of exosomal miRNAs in various diseases, describing how mitochondria are changed in disease status. Finally, we propose future research directions to provide a novel therapeutic strategy that could slow the disease progress mediated by mitochondrial dysfunction.

Long Noncoding RNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 Promotes HIV-1 Replication through Modulating microRNAs in Macrophages

Macrophages can serve as a reservoir for human immunodeficiency-1 (HIV-1) virus in host cells, constituting a barrier to eradication, even in patients who are receiving antiretroviral therapy. Although many noncoding RNAs have been characterized as regulators in HIV-1/AIDS-induced immune response and pathogenesis, only a few long noncoding RNAs (lncRNAs) have demonstrated a close association with HIV-1 replication, and the molecular mechanisms remain unknown. In this study, we investigated how lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), related microRNAs, and key inflammatory genes alter HIV-1 replication in macrophages. Our data show that HIV-1 infection modulates the expression of miR-155 and miR-150-5p in a time-dependent manner, which is regulated by MALAT1. MALAT1 induced suppressor of cytokine signaling 1 (SOCS1) expression by sponging miR-150-5p in HIV-1-infected macrophages and stimulated inflammatory mediators triggering receptor expressed on myeloid cells/cold inducible RNA binding protein (TREM 1/CIRP) ligand/receptor. The RNA immunoprecipitation (RIP) assay validated the direct interaction within the MALAT1/miR-150-5p/SOCS1 axis. HIV-1 infection-mediated upregulation of MALAT1, SOCS1, and HIV-1 Gag was attenuated by SN50 (an NF-кB p50 inhibitor). MALAT1 antisense oligonucleotides (ASOs) suppressed HIV-1 p24 production and HIV-1 Gag gene expression and decreased expression of miR-155 and SOCS1, as well as the production of proinflammatory cytokines by HIV-1-infected macrophages. In conclusion, HIV-1 infection induces MALAT1, which attenuates miR-150-5p expression and increases SOCS1 expression, promoting HIV-1 replication and reactivation. These data provide new insights into how MALAT1 alters the macrophage microenvironment and subsequently promotes viral replication and suggest a potential role for targeting MALAT1 as a therapeutic approach to eliminate HIV-1 reservoirs. IMPORTANCE Viral reservoirs constitute an obstacle to curing HIV-1 diseases, despite antiretroviral therapy. Macrophages serve as viral reservoirs in HIV infection by promoting long-term replication and latency. Recent studies have shown that lncRNAs can modulate virus-host interactions, but the underlying mechanisms are not fully understood. In this study, we demonstrate how lncRNA MALAT1 contributes to HIV-1 replication through modulation of the miR-150/SOCS1 axis in human macrophages. Our findings have the potential to identify new therapies for eliminating HIV-1 reservoirs in immune cells.

The interplay among HIV, monocytes/macrophages, and extracellular vesicles: a systematic review

Despite effective antiretroviral therapies, chronic inflammation and spontaneous viral "blips" occur in HIV-infected patients. Given the roles for monocytes/macrophages in HIV pathogenesis and extracellular vesicles in intercellular communication, we performed this systematic review to delineate the triad of HIV, monocytes/macrophages, and extracellular vesicles in the modulation of immune activation and HIV activities. We searched PubMed, Web of Science, and EBSCO databases for published articles, up to 18 August 2022, relevant to this triad. The search identified 11,836 publications, and 36 studies were deemed eligible and included in this systematic review. Data were extracted for the characteristics of HIV, monocytes/macrophages, and extracellular vesicles used for experiments and the immunologic and virologic outcomes in extracellular vesicle recipient cells. Evidence for the effects on outcomes was synthesized by stratifying the characteristics by outcomes. In this triad, monocytes/macrophages were potential producers and recipients of extracellular vesicles, whose cargo repertoires and functionalities were regulated by HIV infection and cellular stimulation. Extracellular vesicles derived from HIV-infected monocytes/macrophages or the biofluid of HIV-infected patients enhanced innate immune activation and HIV dissemination, cellular entry, replication, and latency reactivation in bystander or infected target cells. These extracellular vesicles could be synthesized in the presence of antiretroviral agents and elicit pathogenic effects in a wide range of nontarget cells. At least eight functional types of extracellular vesicles could be classified based on the diverse extracellular vesicle effects, which were linked to specific virus- and/or host-derived cargos. Thus, the monocyte/macrophage-centered multidirectional crosstalk through extracellular vesicles may help sustain persistent immune activation and residual viral activities during suppressed HIV infection.

Extracellular Vesicles' Role in the Pathophysiology and as Biomarkers in Cystic Fibrosis and COPD

In keeping with the extraordinary interest and advancement of extracellular vesicles (EVs) in pathogenesis and diagnosis fields, we herein present an update to the knowledge about their role in cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). Although CF and COPD stem from a different origin, one genetic and the other acquired, they share a similar pathophysiology, being the CF transmembrane conductance regulator (CFTR) protein implied in both disorders. Various subsets of EVs, comprised mainly of microvesicles (MVs) and exosomes (EXOs), are secreted by various cell types that are either resident or attracted in the airways during the onset and progression of CF and COPD lung disease, representing a vehicle for metabolites, proteins and RNAs (especially microRNAs), that in turn lead to events as such neutrophil influx, the overwhelming of proteases (elastase, metalloproteases), oxidative stress, myofibroblast activation and collagen deposition. Eventually, all of these pathomechanisms lead to chronic inflammation, mucus overproduction, remodeling of the airways, and fibrosis, thus operating a complex interplay among cells and tissues. The detection of MVs and EXOs in blood and biological fluids coming from the airways (bronchoalveolar lavage fluid and sputum) allows the consideration of EVs and their cargoes as promising biomarkers for CF and COPD, although clinical expectations have yet to be fulfilled.

Vascular Endothelial Growth Factor Receptor 2: Molecular Mechanism and Therapeutic Potential in Preeclampsia Comorbidity with Human Immunodeficiency Virus and Severe Acute Respiratory Syndrome Coronavirus 2 Infections

This review explored the role of vascular endothelial growth factor receptor-2 (VEGFR-2) in the synergy of preeclampsia (PE), human immunodeficiency virus (HIV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Downregulation of VEGFR-2 in PE promotes endothelial dysfunction and prevents endothelial cell (EC) migration, proliferation, and differentiation. The HIV-1 accessory protein, tat (trans-activator of transcription), prevents VEGFR-2 signaling via the vascular endothelial growth factor A (VEGF-A) ligand. Combined antiretroviral therapy (cART) may cause immune reconstitution, impaired decidualization, and endothelial injury, thus may be a risk factor for PE development. The VEGF/VEGFR-2 interaction may be associated with SARS-CoV-2-related pulmonary oedema. Endothelial dysfunction and heightened inflammation are both associated with PE, HIV, and SARS-CoV-2 infection; therefore, it is plausible that both characteristics may be exacerbated in the synergy of these events. In addition, this review explored microRNAs (miR) regulating VEGFR-2. An overexpression of miR-126 is evident in PE, HIV, and SARS-CoV-2 infection; thus, modulating the expression of miR-126 may be a therapeutic strategy. However, the involvement of microRNAs in PE, HIV, and SARS-CoV-2 infection needs further investigating. Since these conditions have been evaluated independently, this review attempts to predict their clinical manifestations in their synergy, as well as independently; thereby providing a platform for early diagnosis and therapeutic potential in PE, HIV, and SARS-CoV-2 infection.

Macrophage-derived exosomal aminopeptidase N aggravates sepsis-induced acute lung injury by regulating necroptosis of lung epithelial cell

Sepsis-induced acute lung injury (ALI) is a serious sepsis complication and the prevailing cause of death. Circulating plasma exosomes might exert a key role in regulating intercellular communication between immunological and structural cells, as well as contributing to sepsis-related organ damage. However, the molecular mechanisms by which exosome-mediated intercellular signaling exacerbate ALI in septic infection remains undefined. Therefore, we investigated the effect of macrophage-derived exosomal APN/CD13 on the induction of epithelial cell necrosis. Exosomal APN/CD13 levels in the plasma of septic mice and patients with septic ALI were found to be higher. Furthermore, increased plasma exosomal APN/CD13 levels were associated with the severity of ALI and fatality in sepsis patients. We found remarkably high expression of APN/CD13 in exosomes secreted by LPS-stimulated macrophages. Moreover, c-Myc directly induced APN/CD13 expression and was packed into exosomes. Finally, exosomal APN/CD13 from macrophages regulated necroptosis of lung epithelial cells by binding to the cell surface receptor TLR4 to induce ROS generation, mitochondrial dysfunction and NF-κB activation. These results demonstrate that macrophage-secreted exosomal APN/CD13 can trigger epithelial cell necroptosis in an APN/CD13-dependent manner, which provides insight into the mechanism of epithelial cell functional disorder in sepsis-induced ALI.

Necroptosis of lung epithelial cells is regulated by aminopeptidase N levels in circulating plasma exosomes in patients and mice with sepsis-induced acute lung injury.

Overview and Update on Extracellular Vesicles: Considerations on Exosomes and Their Application in Modern Medicine

In recent years, there has been a rapid growth in the knowledge of cell-secreted extracellular vesicle functions. They are membrane enclosed and loaded with proteins, nucleic acids, lipids, and other biomolecules. After being released into the extracellular environment, some of these vesicles are delivered to recipient cells; consequently, the target cell may undergo physiological or pathological changes. Thus, extracellular vesicles as biological nano-carriers, have a pivotal role in facilitating long-distance intercellular communication. Understanding the mechanisms that mediate this communication process is important not only for basic science but also in medicine. Indeed, extracellular vesicles are currently seen with immense interest in nanomedicine and precision medicine for their potential use in diagnostic, prognostic, and therapeutic applications. This paper aims to summarize the latest advances in the study of the smallest subtype among extracellular vesicles, the exosomes. The article is divided into several sections, focusing on exosomes' nature, characteristics, and commonly used strategies and methodologies for their separation, characterization, and visualization. By searching an extended portion of the relevant literature, this work aims to give a quick outline of advances in exosomes' extensive nanomedical applications. Moreover, considerations that require further investigations before translating them to clinical applications are summarized.

Characteristics of the MicroRNA Expression Profile of Exosomes Released by Vero Cells Infected with Porcine Epidemic Diarrhea Virus

Exosomes are nanoscale vesicles actively secreted by a variety of cells. They contain regulated microRNA (miRNA), allowing them to function in intercellular communication. In the present study, the role of exosomal miRNAs in porcine epidemic diarrhea virus (PEDV) infection was investigated using exosomes isolated from Vero cells infected with PEDV. The results of transmission electron microscopy observation showed that the exosomes are spherical in shape, uniform in size, and negatively stained in the membrane. Nanoparticle tracking analysis showed that the average exosome particle size is 130.5 nm. The results of miRNA sequencing showed that, compared with the control group, a total of 115 miRNAs are abnormally expressed in the exosomes of infected cells. Of these, 80 miRNAs are significantly upregulated and 35 miRNAs are significantly downregulated. Functional annotation analysis showed that the differentially expressed miRNAs are associated with PEDV infection through interaction with the cAMP, Hippo, TGF-beta, HIF-1, FoxO, MAPK, and Ras signaling pathways. Thus, our findings provide important information about the effects of PEDV infection on exosomal miRNA expression and will aid the search for potential anti-PEDV drug candidates.

Metabolic Reprogramming in HIV-Associated Neurocognitive Disorders

A significant number of patients infected with HIV-1 suffer from HIV-associated neurocognitive disorders (HAND) such as spatial memory impairments and learning disabilities (SMI-LD). SMI-LD is also observed in patients using combination antiretroviral therapy (cART). Our lab has demonstrated that the HIV-1 protein, gp120, promotes SMI-LD by altering mitochondrial functions and energy production. We have investigated cellular processes upstream of the mitochondrial functions and discovered that gp120 causes metabolic reprogramming. Effectively, the addition of gp120 protein to neuronal cells disrupted the glycolysis pathway at the pyruvate level. Looking for the players involved, we found that gp120 promotes increased expression of polypyrimidine tract binding protein 1 (PTBP1), causing the splicing of pyruvate kinase M (PKM) into PKM1 and PKM2. We have also shown that these events lead to the accumulation of advanced glycation end products (AGEs) and prevent the cleavage of pro-brain-derived neurotrophic factor (pro-BDNF) protein into mature brain-derived neurotrophic factor (BDNF). The accumulation of proBDNF results in signaling that increases the expression of the inducible cAMP early repressor (ICER) protein which then occupies the cAMP response element (CRE)-binding sites within the BDNF promoters II and IV, thus altering normal synaptic plasticity. We reversed these events by adding Tepp-46, which stabilizes the tetrameric form of PKM2. Therefore, we concluded that gp120 reprograms cellular metabolism, causing changes linked to disrupted memory in HIV-infected patients and that preventing the disruption of the metabolism presents a potential cure against HAND progression.

Mechanisms contributing to adverse outcomes of COVID-19 in obesity

A growing amount of epidemiological data from multiple countries indicate an increased prevalence of obesity, more importantly central obesity, among hospitalized subjects with COVID-19. This suggests that obesity is a major factor contributing to adverse outcome of the disease. As it is a metabolic disorder with dysregulated immune and endocrine function, it is logical that dysfunctional metabolism contributes to the mechanisms behind obesity being a risk factor for adverse outcome in COVID-19. Emerging data suggest that in obese subjects, (a) the molecular mechanisms of viral entry and spread mediated through ACE2 receptor, a multifunctional host cell protein which links to cellular homeostasis mechanisms, are affected. This includes perturbation of the physiological renin-angiotensin system pathway causing pro-inflammatory and pro-thrombotic challenges (b) existent metabolic overload and ER stress-induced UPR pathway make obese subjects vulnerable to severe COVID-19, (c) host cell response is altered involving reprogramming of metabolism and epigenetic mechanisms involving microRNAs in line with changes in obesity, and (d) adiposopathy with altered endocrine, adipokine, and cytokine profile contributes to altered immune cell metabolism, systemic inflammation, and vascular endothelial dysfunction, exacerbating COVID-19 pathology. In this review, we have examined the available literature on the underlying mechanisms contributing to obesity being a risk for adverse outcome in COVID-19.

Extracellular vesicles released by non-small cell lung cancer cells drive invasion and permeability in non-tumorigenic lung epithelial cells

Extracellular vesicles (EVs) released from non-small cell lung cancer (NSCLC) cells are known to promote cancer progression. However, it remains unclear how EVs from various NSCLC cells differ in their secretion profile and their ability to promote phenotypic changes in non-tumorigenic cells. Here, we performed a comparative analysis of EV release from non-tumorigenic cells (HBEC/BEAS-2B) and several NSCLC cell lines (A549, H460, H358, SKMES, and Calu6) and evaluated the potential impact of NSCLC EVs, including EV-encapsulated RNA (EV-RNA), in driving invasion and epithelial barrier impairment in HBEC/BEAS-2B cells. Secretion analysis revealed that cancer cells vary in their secretion level, with some cell lines having relatively low secretion rates. Differential uptake of NSCLC EVs was also observed, with uptake of A549 and SKMES EVs being the highest. Phenotypically, EVs derived from Calu6 and H358 cells significantly enhanced invasion, disrupted an epithelial barrier, and increased barrier permeability through downregulation of E-cadherin and ZO-1. EV-RNA was a key contributing factor in mediating these phenotypes. More nuanced analysis suggests a potential correlation between the aggressiveness of NSCLC subtypes and the ability of their respective EVs to induce cancerous phenotypes.

Emerging role of non-coding RNAs in the course of HIV infection

Recent studies have shown that non-coding region of the human genome can exert important regulatory roles on critical biological functions, including response to viral infections, among them is human immunodeficiency virus (HIV). HIV/AIDS is characterized by a gradual diminution of CD4 + T cells resulting in progressive deterioration of host immune responses and eventually high vulnerability to opportunistic infections and cancer. T cells functions have been shown to be delicately regulated by an active functional network of non-coding RNAs. Several lncRNAs such as MALAT1, NEAT1, GAS5, LOC102549805, NKILA, BACE1-AS, LINC00313, RP11-539L10.2, PVT1, LINC00173, NRON and AK130181 have been found to affect response of immune system to HIV or its pathological consequences. Moreover, numerous miRNAs such as hsa-miR-191-5p, miR-155, miR-103, miR-107, miR-150, miR-144, miR-125b, miR-146a, miR-146b-5p and miR-15a are involved in this process. In the current manuscript, we explain the role of lncRNAs and miRNAs in the regulation of response to HIV infection, apoptosis and activity of T cells, reactivation or latency of this virus and even pathological manifestations such as Tat-mediated induction of astrocytic amyloidosis.

High Glucose Reduces the Paracellular Permeability of the Submandibular Gland Epithelium via the MiR-22-3p/Sp1/Claudin Pathway

Tight junctions (TJs) play an important role in water, ion, and solute transport through the paracellular pathway of epithelial cells; however, their role in diabetes-induced salivary gland dysfunction remains unknown. Here, we found that the TJ proteins claudin-1 and claudin-3 were significantly increased in the submandibular glands (SMGs) of db/db mice and high glucose (HG)-treated human SMGs. HG decreased paracellular permeability and increased claudin-1 and claudin-3 expression in SMG-C6 cells. Knockdown of claudin-1 or claudin-3 reversed the HG-induced decrease in paracellular permeability. MiR-22-3p was significantly downregulated in diabetic SMGs and HG-treated SMG-C6 cells. A miR-22-3p mimic suppressed claudin-1 and claudin-3 expression and abolished the HG-induced increases in claudin-1 and claudin-3 levels in SMG-C6 cells, whereas a miR-22-3p inhibitor produced the opposite effects. Specificity protein-1 (Sp1) was enhanced in diabetic SMGs and HG-treated SMG-C6 cells, which promoted claudin-1 and claudin-3 transcription through binding to the corresponding promoters. A luciferase reporter assay confirmed that miR-22-3p repressed Sp1 by directly targeting the Sp1 mRNA 3′-untranslated region (3′-UTR). Consistently, the miR-22-3p mimic suppressed, whereas the miR-22-3p inhibitor enhanced, the effects of HG on Sp1 expression. Taken together, our results demonstrate a new regulatory pathway through which HG decreases the paracellular permeability of SMG cells by inhibiting miR-22-3p/Sp1-mediated claudin-1 and claudin-3 expression.

The Role of Extracellular Vesicles from Human Macrophages on Host-Pathogen Interaction

The nano-sized membrane enclosed extracellular vesicles (EVs) released by virtually all cell types play an essential role in intercellular communication via delivering bio-molecules, such as nucleic acids, proteins, lipids, and other molecules to recipient cells. By mediating an active and steady-state cell-to-cell communication, EVs contribute to regulating and preserving cellular homeostasis. On the other hand, EVs can also spread pathogen-derived molecules during infections, subverting the host immune responses during infections and thus worsening pathophysiological processes. In recent years, the biological functioning of EVs has become a widespread research field in basic and clinical branches of medical sciences due to their potential role in therapeutic applications for several diseases. This review aims to summarize the main recent findings regarding the implication of EVs shed by human macrophages (MΦ-EVs) and how they can modulate the host immune response to control or increase the damage caused by infectious agents. We will also present the methods used to describe MΦ-EVs, as well as the potential of these EVs as disease diagnostic tools for some human pathogens. We believe that an in-depth understanding of the host–pathogen interactions mediated by MΦ-EVs may trigger the development of innovative therapeutic strategies against infectious diseases.

Exosomal microRNA-503-3p derived from macrophages represses glycolysis and promotes mitochondrial oxidative phosphorylation in breast cancer cells by elevating DACT2

MicroRNAs (miRNAs) are emerging drivers in tumor progression, while the role of miR-503-3p in breast cancer (BC) remains largely unknown. We aimed to explore the impact of macrophage-derived exosomal miR-503-3p in the development of BC by regulating disheveled-associated binding antagonist of beta-catenin 2 (DACT2). miR-503-3p and DACT2 expression in BC tissues and cells was assessed, and the expression of Wnt/β-catenin signaling pathway-related proteins in BC cells was also evaluated. Macrophages were induced and exosomes were extracted. The screened BC cell lines were, respectively, treated with exosomes, miR-503-3p inhibitor/mimic or upregulated/inhibited DACT2, and then the phenotypes, glucose intake, oxygen consumption rate, and adenosine-triphosphate (ATP) level of BC cells were determined. Cell growth in vivo was also observed. MiR-503-3p was elevated, DACT2 was reduced, and Wnt/β-catenin signaling pathway was activated in BC cells. Macrophage-derived exosomes, upregulated miR-503-3p or inhibited DACT2 promoted malignant behaviors of BC cells, glucose intake, and activity of the Wnt/β-catenin signaling pathway, while repressed oxygen consumption rate and ATP level in BC cells. Reversely, reduced miR-503-3p or upregulated DACT2 exerted opposite effects. This study revealed that reduction of macrophage-derived exosomal miR-503-3p repressed glycolysis and promoted mitochondrial oxidative phosphorylation in BC by elevating DACT2 and inactivating Wnt/β-catenin signaling pathway. Our research may provide novel targets for BC treatment.

The effect of extracellular vesicles on the regulation of mitochondria under hypoxia

Mitochondria are indispensable organelles for maintaining cell energy metabolism, and also are necessary to retain cell biological function by transmitting information as signal organelles. Hypoxia, one of the important cellular stresses, can directly regulates mitochondrial metabolites and mitochondrial reactive oxygen species (mROS), which affects the nuclear gene expression through mitochondrial retrograde signal pathways, and also promotes the delivery of signal components into cytoplasm, causing cellular injury. In addition, mitochondria can also trigger adaptive mechanisms to maintain mitochondrial function in response to hypoxia. Extracellular vesicles (EVs), as a medium of information transmission between cells, can change the biological effects of receptor cells by the release of cargo, including nucleic acids, proteins, lipids, mitochondria, and their compositions. The secretion of EVs increases in cells under hypoxia, which indirectly changes the mitochondrial function through the uptake of contents by the receptor cells. In this review, we focus on the mitochondrial regulation indirectly through EVs under hypoxia, and the possible mechanisms that EVs cause the changes in mitochondrial function. Finally, we discuss the significance of this EV-mitochondria axis in hypoxic diseases.

Oncogenic Effects of HIV-1 Proteins, Mechanisms Behind

People living with human immunodeficiency virus (HIV-1) are at increased risk of developing cancer, such as Kaposi sarcoma (KS), non-Hodgkin lymphoma (NHL), cervical cancer, and other cancers associated with chronic viral infections. Traditionally, this is linked to HIV-1-induced immune suppression with depletion of CD4+ T-helper cells, exhaustion of lymphopoiesis and lymphocyte dysfunction. However, the long-term successful implementation of antiretroviral therapy (ART) with an early start did not preclude the oncological complications, implying that HIV-1 and its antigens are directly involved in carcinogenesis and may exert their effects on the background of restored immune system even when present at extremely low levels. Experimental data indicate that HIV-1 virions and single viral antigens can enter a wide variety of cells, including epithelial. This review is focused on the effects of five viral proteins: envelope protein gp120, accessory protein negative factor Nef, matrix protein p17, transactivator of transcription Tat and reverse transcriptase RT. Gp120, Nef, p17, Tat, and RT cause oxidative stress, can be released from HIV-1-infected cells and are oncogenic. All five are in a position to affect "innocent" bystander cells, specifically, to cause the propagation of (pre)existing malignant and malignant transformation of normal epithelial cells, giving grounds to the direct carcinogenic effects of HIV-1.

A Protocol for Isolation, Purification, Characterization, and Functional Dissection of Exosomes

Extracellular vesicles (EVs) are membrane-enclosed vesicles released by cells. They carry proteins, nucleic acids, and metabolites which can be transferred to a recipient cell, locally or at a distance, to elicit a functional response. Since their discovery over 30 years ago, the functional repertoire of EVs in both physiological (e.g., organ morphogenesis, embryo implantation) and pathological (e.g., cancer, neurodegeneration) conditions has cemented their crucial role in intercellular communication. Moreover, because the cargo encapsulated within circulating EVs remains protected from degradation, their diagnostic as well as therapeutic (such as drug delivery tool) applications have garnered vested interest. Global efforts have been made to purify EV subtypes from biological fluids and in vitro cell culture media using a variety of strategies and techniques, with a major focus on EVs of endocytic origin called exosomes (30-150 nm in size). Given that the secretome comprises of soluble secreted proteins, protein aggregates, RNA granules, and EV subtypes (such as exosomes, shed microvesicles, apoptotic bodies), it is imperative to purify exosomes to homogeneity if we are to perform biochemical and biophysical characterization and, importantly, functional dissection. Besides understanding the composition of EV subtypes, defining molecular bias of how they reprogram target cells also remains of paramount importance in this area of active research. Here, we outline a systematic "how to" protocol (along with useful insights/tips) to obtain highly purified exosomes and perform their biophysical and biochemical characterization. This protocol employs a mass spectrometry-based proteomics approach to characterize the protein composition of exosomes. We also provide insights on different isolation strategies and their usefulness in various downstream applications. We outline protocols for lipophilic labeling of exosomes to study uptake by a recipient cell, investigating cellular reprogramming using proteomics and studying functional response to exosomes in the Transwell-Matrigel™ Invasion assay.

Exosome: A Review of Its Classification, Isolation Techniques, Storage, Diagnostic and Targeted Therapy Applications

Exosomes are nano-sized small extracellular vesicles secreted by cells, carrying nucleic acids, proteins, lipids and other bioactive substances to play a role in the body's physiological and pathological processes. Compared to synthetic carriers such as liposomes and nanoparticles, the endogeneity and heterogeneity of exosomes give them extensive and unique advantages in the field of disease diagnosis and treatment. However, the storage stability, low yield, low purity, and weak targeting of exosomes limit its clinical application. For this reason, further exploration is needed to optimize the above problems and facilitate future functional studies of exosomes. In this paper, the origin, classification, preparation and characterization, storage stability and applications of exosome delivery system are summarized and discussed by searching a large number of literatures.

LncRNA MM2P-induced, exosome-mediated transfer of Sox9 from monocyte-derived cells modulates primary chondrocytes

Monocyte-derived cells were shown to promote cartilage repair in osteoarthritis. The role of the long non-coding RNA (lncRNA) MM2P in this function of monocyte-derived cells remained unexplored. Treatment of RAW264.7 murine macrophages and mouse bone marrow-derived macrophages with IL-4 or IL-13 upregulated MM2P expression, upstream of STAT3 and STAT6 phosphorylation. Specifically, MM2P blocked SHP2-mediated dephosphorylation of STAT3 at Try705 and interacted with the RNA-binding protein FUS. In turn, p-STAT3 increased the Sox9 gene expression. These cells released Sox9 mRNA and protein-containing exosomes, as demonstrated by a transmission electron microscope, nanoparticle tracking analysis, and detection of typical surface markers. Their culture supernatant promoted the differentiation of mouse primary chondrocytes, i.e., upregulated the expression of Col1a2 and Acan genes and promoted the secretion of extracellular matrix components proteoglycan and type II collagen. These effects were mediated by Sox9 mRNA and protein delivered to chondrocytes by exosomes. Together, ex vivo treatment of monocyte-derived cells with IL-4 or IL-13 promoted chondrocyte differentiation and functions through exosome-mediated delivery of Sox9 mRNA and protein.

Fungal-host interactions: insights into microRNA in response to Paracoccidioides species

BACKGROUND

Paracoccidioides spp. causes paracoccidioidomycosis (PCM), an important and frequent systemic mycosis that occurs in Latin America. The infectious process begins with contact between the fungus and lung cells, and the molecular pattern of this interaction is currently poorly understood. MicroRNAs (miRNAs) are small non-coding RNAs that regulate the gene expression in many biological processes, including in the infections.

OBJECTIVE

This study aimed to analyse the expression of miRNAs in lung cells as response to infection by Paracoccidioides spp.

METHODS

A quantitative real-time polymerase chain reaction (RT-qPCR) based screening was employed to verify differentially expressed miRNAs in human lung cells infected with three different species; Paracoccidioides lutzii, Paracoccidioides americana, and Paracoccidioides brasiliensis. Furthermore, the in silico predictions of target genes and pathways for miRNAs were obtained.

FINDINGS

The results showed that miRNAs identified in the lung cells were different according to the species studied. However, based on the predicted targets, the potential signaling pathways regulated by miRNAs are common and related to adhesion, actin cytoskeleton rearrangement, apoptosis, and immune response mediated by T cells and TGF-β.

MAIN CONCLUSIONS

In summary, this study showed the miRNAs pattern of epithelial cells in response to infection by Paracoccidioides species and the potential role of these molecules in the regulation of key pathogenesis mechanisms of PCM.

M2 Macrophagy-derived exosomal miRNA-5106 induces bone mesenchymal stem cells towards osteoblastic fate by targeting salt-inducible kinase 2 and 3

BACKGROUND

Osteoblast differentiation is a vital process for fracture healing, and exosomes are nanosized membrane vesicles that can deliver therapeutic drugs easily and safely. Macrophages participate in the regulation of various biological processes in vivo, and macrophage-derived exosomes (MD-Exos) have recently been a topic of increasing research interest. However, few study has explored the link between MD-Exos and osteoblast differentiation. Herein, we sought to identify miRNAs differentially expressed between M1 and M2 macrophage-derived exosomes, and to evaluate their roles in the context of osteoblast differentiation.

RESULTS

We found that microRNA-5106 (miR-5106) was significantly overexpressed in M2 macrophage-derived exosomes (M2D-Exos), while its expression was decreased in M1 macrophage-derived exosomes (M1D-Exos), and we found that this exosomal miRNA can induce bone mesenchymal stem cell (BMSC) osteogenic differentiation via directly targeting the Salt-inducible kinase 2 and 3 (SIK2 and SIK3) genes. In addition, the local injection of both a miR-5106 agonist or M2D-Exos to fracture sites was sufficient to accelerate healing in vivo.

CONCLUSIONS

Our study demonstrates that miR-5106 is highly enriched in M2D-Exos, and that it can be transferred to BMSCs wherein it targets SIK2 and SIK3 genes to promote osteoblast differentiation.

Mesenchymal stromal cell-derived exosomes ameliorate peripheral neuropathy in a mouse model of diabetes

AIMS/HYPOTHESIS

Diabetic peripheral neuropathy (DPN) is one of the major complications of diabetes, which contributes greatly to morbidity and mortality. There is currently no effective treatment for this disease. Exosomes are cell-derived nanovesicles and play an important role in intercellular communications. The present study investigated whether mesenchymal stromal cell (MSC)-derived exosomes improve neurological outcomes of DPN.

METHODS

Exosomes were isolated from the medium of cultured mouse MSCs by ultracentrifugation. Diabetic mice (BKS.Cg-m+/+Lepr^db/J, db/db) at the age of 20 weeks were used as DPN models. Heterozygous mice (db/m) of the same age were used as the control. MSC-exosomes were administered weekly via the tail vein for 8 weeks. Neurological function was evaluated by testing motor and sensory nerve conduction velocities, and thermal and mechanical sensitivity. Morphometric analysis was performed by myelin sheath staining and immunohistochemistry. Macrophage markers and circulating cytokines were measured by western blot and ELISA. MicroRNA (miRNA) array and bioinformatics analyses were performed to examine the exosomal miRNA profile and miRNA putative target genes involved in DPN.

RESULTS

Treatment of DPN with MSC-exosomes markedly decreased the threshold for thermal and mechanical stimuli and increased nerve conduction velocity in diabetic mice. Histopathological analysis showed that MSC-exosomes markedly augmented the density of FITC-dextran perfused blood vessels and increased the number of intraepidermal nerve fibres (IENFs), myelin thickness and axonal diameters of sciatic nerves. Western blot analysis revealed that MSC-exosome treatment decreased and increased M1 and M2 macrophage phenotype markers, respectively. Moreover, MSC-exosomes substantially suppressed proinflammatory cytokines. Bioinformatics analysis revealed that MSC-exosomes contained abundant miRNAs that target the Toll-like receptor (TLR)4/NF-κB signalling pathway.

CONCLUSIONS/INTERPRETATION

MSC-derived exosomes alleviate neurovascular dysfunction and improve functional recovery in mice with DPN by suppression of proinflammatory genes.

Retracted Article: Macrophage-derived exosomes mediate osteosarcoma cell behavior by activating AKT signaling

Osteosarcoma is the most common type of bone tumor, which severely threatens the health of adolescents and young adults. Tumor-infiltrating macrophages have been shown to mediate cancer progression via extracellular vesicles. However, their potential mechanisms in osteosarcoma progression and in drug-resistance are still not yet known. The macrophage cell line THP1 was stimulated by phorbol myristate acetate (PMA) to secrete exosomes. The exosomes isolated from THP1 were characterized via transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and by a western blot. Cell proliferation was determined using CCK-8. A transwell assay and flow cytometry were conducted to detect cell migration and apoptosis, respectively. The expression levels of AKT and its phosphorylation status were determined using a western blot. PMA-treated activated THP1 cells secreted an abundance of exosomes with the characteristics of being less than 200 nm in diameter, and showing the robust expression of exosome markers CD63 and CD81. The THP1-derived exosomes promoted cell proliferation, migration and drug-resistance to the chemical drug docetaxel in both osteosarcoma cell lines MG63 and 143B. The inhibition of the generation of exosomes by the knockdown of ALIX clearly suppressed the cell proliferation, migration and drug-resistance. Mechanistically, the THP1-derived exosomes activated AKT signaling by inducing the increased expression of the phosphorylated AKT at serine 473 (p-AKT). The AKT inhibitor MK2206 significantly abolished exosome-mediated cell proliferation and drug-resistance in osteosarcoma cells. In summary, our data demonstrated that macrophage-derived exosomes promoted osteosarcoma progression and drug-resistance by activating AKT signaling that could be used as a potential molecular target for osteosarcoma treatment.

Osteosarcoma is the most common type of bone tumor, which severely threatens the health of adolescents and young adults.