Lymphocyte-derived microparticles induce apoptosis of airway epithelial cells through activation of p38 MAPK and production of arachidonic acid

The role of extracellular vesicles in COPD and potential clinical value

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung disease and a major health burden worldwide. Extracellular vesicles (EVs) are nanosized vesicles which possess a lipid bilayer structure that are secreted by various cells. They contain a variety of bioactive substances, which can regulate various physiological and pathological processes and are closely related to the development of diseases. Recently, EVs have emerged as a novel tool for intercellular crosstalk, which plays an essential role in COPD development. This paper reviews the role of EVs in the development of COPD and their potential clinical value, in order to provide a reference for further research on COPD.

Exploring the Profile of Cell Populations and Soluble Immunological Mediators in Bothrops atrox Envenomations

Bothrops atrox envenomations are common in the Brazilian Amazon. The venom of B. atrox is highly inflammatory, which results in severe local complications, including the formation of blisters. Moreover, there is little information on the immune mechanisms associated with this condition. Thus, a longitudinal study was carried out to characterize the profile of the cell populations and soluble immunological mediators in the peripheral blood and blisters in B. atrox patients s according to their clinical manifestations (mild and severe). A similar response in both B. atrox patient groups (MILD and SEV) was observed, with an increase in inflammatory monocytes, NKT, and T and B cells, as well as CCL2, CCL5, CXCL9, CXCL10, IL-1β and IL-10, when compared with the group of healthy blood donors. After the administration of antivenom, the participation of patrolling monocytes and IL-10 in the MILD group was observed. In the SEV group, the participation of B cells was observed, with high levels of CCL2 and IL-6. In the blister exudate, a hyperinflammatory profile was observed. In conclusion, we revealed the involvement of cell populations and soluble mediators in the immune response to B. atrox envenomation at the local and peripheral level, which is related to the onset and extent of the inflammation/clinical manifestation.

Carbon nanomaterial-treated cell cultures of Nostoc flagelliforme produce exopolysaccharides with ameliorative physio-chemical properties

The feasibility and efficiency of carbon nanomaterials (CNMs) in algal biotechnology are less known. In this study, the influences of four CNMs, graphene (G), graphene oxide (GO), multiwalled carbon nanotube (MWCNT), and aminated multiwalled carbon nanotube (MWCNT-NH₂), on cell growth and exopolysaccharide (EPS) production, as well as the physiochemical properties of EPS, were investigated in cell culture of Nostoc flagelliforme. A proper concentration (15 mg L^-1) of four CNMs was chosen for use after a preliminary test. Upon GO treatment, the biomass was improved by 11.1 % and the EPS production was increased by 36.1 % on day 16 compared to the nontreated control. Four CNM treatments significantly improved cellular O₂·^- and H₂O₂ levels as well as superoxide dismutase and catalase activities. The monosaccharide compositions and functional groups of the EPSs were obviously altered by the CNM treatments. Particularly, the GO treatment-resulting EPS showed obviously improved flocculating ability, water absorption ability, and reactive oxygen species scavenging ability. In general, four CNMs exerted distinct influences on the production and physio-chemical property alteration of the EPS in N. flagelliforme culture. This work expands our understanding of the application of CNMs in the induced production and functional modification of polysaccharides during algal cultivation.

Particulate Matter Exposure and Allergic Rhinitis: The Role of Plasmatic Extracellular Vesicles and Bacterial Nasal Microbiome

Particulate matter (PM) exposure is linked to the worsening of respiratory conditions, including allergic rhinitis (AR), as it can trigger nasal and systemic inflammation. To unveil the underlying molecular mechanisms, we investigated the effects of PM exposure on the release of plasmatic extracellular vesicles (EV) and on the complex cross-talk between the host and the nasal microbiome. To this aim, we evaluated the effects of PM₁₀ and PM_2.5 exposures on both the bacteria-derived-EV portion (bEV) and the host-derived EVs (hEV), as well as on bacterial nasal microbiome (bNM) features in 26 AR patients and 24 matched healthy subjects (HS). In addition, we assessed the role exerted by the bNM as a modifier of PM effects on the complex EV signaling network in the paradigmatic context of AR. We observed that PM exposure differently affected EV release and bNM composition in HS compared to AR, thus potentially contributing to the molecular mechanisms underlying AR. The obtained results represent the first step towards the understanding of the complex signaling network linking external stimuli, bNM composition, and the immune risponse.

MicroRNA-181a suppresses norethisterone-promoted tumorigenesis of breast epithelial MCF10A cells through the PGRMC1/EGFR-PI3K/Akt/mTOR signaling pathway

BACKGROUND

Research suggests that hormone replacement therapy may increase the risk of breast cancer, and progestins such as norethisterone (NET) play a key role in this phenomenon. We have demonstrated that microRNA-181a (miR-181a) suppresses NET-promoted breast cancer cell survival. Nonetheless, the effects of NET and miR-181a on the tumorigenesis of human breast epithelial cells have not yet been elaborated.

METHODS

Assays of cell viability, proliferation, migration, apoptosis, and colony formation were performed to investigate the pro-tumorigenesis effect of NET and the effects of miR-181a on human breast epithelial MCF10A cells. The expressions of cell-proliferation-related genes and apoptotic factors were analyzed by quantitative RT-PCR and Western blot in MCF10A cells treated with NET and miR-181a.

RESULTS

NET significantly increased MCF10A cell viability, proliferation, migration, and colony formation, but reduced cellular apoptosis. In addition, NET increased the expression of progesterone receptor membrane component 1 (PGRMC1), EGFR, B-cell lymphoma 2, cyclin D1, and proliferating cell nuclear antigen, but decreased the expression of pro-apoptosis factors, such as Bax, caspase-7, and caspase-9. Overexpression of miR-181a strongly inhibited the effects of NET on MCF10A cells and abrogated NET-stimulated PGRMC1, EGFR, and mTOR expression.

CONCLUSIONS

Activation of the PGRMC1/EGFR-PI3K/Akt/mTOR signaling pathway is the primary mechanism underlying the pro-tumorigenesis effects of NET on human breast epithelial MCF10A cells. Additionally, miR-181a can suppress the effects of NET on these cells. These data suggest a therapeutic potential for miR-181a in reducing or preventing the risk of breast cancer in hormone replacement therapy using NET.

Lymphocytic microparticles suppress retinal angiogenesis via targeting Müller cells in the ischemic retinopathy mouse model

Retinopathy of prematurity (ROP) is the primary cause of visual impairment and vision loss in premature infants, which results from the formation of aberrant retinal neovascularization (NV). An emerging body of evidence has shown that Müller cells are the predominant source of vascular endothelial growth factor (VEGF), which also serves as a chemoattractant for monocyte/macrophage lineage. The recruitment of macrophages is increased during retinal NV, and they exert a pro-angiogenic role in ROP. We have shown that lymphocytic microparticles (microvesicles; LMPs) derived from apoptotic human T lymphocytes possess strong angiogenesis-inhibiting properties. Here, we investigated the effect of LMPs on the chemotactic capacity of Müller cells in vitro using rat Müller cell rMC-1 and mouse macrophage RAW 264.7. In addition, the impact of LMPs was determined in vivo using a mouse model of oxygen-induced ischemic retinopathy (OIR). The results revealed that LMPs were internalized by rMC-1 and reduced their cell proliferation dose-dependently without inducing cell apoptosis. LMPs inhibited the chemotactic capacity of rMC-1 on RAW 264.7 via reducing the expression of VEGF. Moreover, LMPs attenuated pathological retinal NV and the infiltration of macrophages in vivo. LMPs downregulated ERK1/2 and HIF-1α both in vitro and in vivo. These findings expand our understanding of the effects of LMPs, providing evidence of LMPs as a promising therapeutic approach for the treatment of retinal NV diseases.

Increased airway T lymphocyte microparticles in chronic obstructive pulmonary disease induces airway epithelial injury

In our previous study, T lymphocyte microparticles (TLMPs) originated from CEM T lymphoblast-like cell line induced enhanced production of inflammation-associated cytokines and apoptosis in human bronchial epithelial cells (HBEs). To measure TLMP subpopulations in bronchoalveolar lavage fluids (BALF) from patients with chronic obstructive pulmonary disease (COPD), and to explore the effects of MPs derived from different T cell subpopulations on airway epithelium, this study was conducted. A hospital-based case-control study including 47 COPD patients and 28 healthy volunteers was performed. The cellular origins of MPs from airway in COPD and controls were evaluated using flow cytometry. CD4⁺ or CD8⁺ TLMPs were isolated by MACS to investigate their effects on HBEs in vitro. The numbers of MPs derived from T lymphocytes in BALF as well as these subpopulations (CD4⁺ and CD8⁺ T lymphocytes) were significantly upregulated in COPD patients compared with healthy volunteers. However, there was no significant difference between stable COPD and patients with acute exacerbation. Additionally, significant correlation between CD4⁺ and CD8⁺ TLMPs was observed, however neither type nor total level of TLMPs was correlated with any base parameter. Furthermore, isolated CD4⁺ and CD8⁺ TLMPs reduced cell viability and induced significant production of inflammatory cytokines including interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, MCP-2, matrix metallopeptidase (MMP)-9 and tumor necrosis factor-alpha (TNF-α) in HBEs, while the levels of anti-inflammatory cytokine IL-10 were decreased. TLMPs in the airways, as putative biomarkers, may lead to airway epithelial injury and inflammation and serve essential roles in the pathophysiology of COPD.

Activation of NLRP3 inflammasome by lymphocytic microparticles via TLR4 pathway contributes to airway inflammation

The presence of elevated T lymphocytic microparticles (TLMPs) during respiratory illness is associated with airway and lung inflammation and epithelial injuries. Although inflammasome and IL-1β signaling are crucial in airway inflammation, little was known about their regulatory mechanism. We hypothesized that TLMPs trigger inflammasome activation and IL-1β production in bronchial and alveolar epithelial cells to induce airway and lung inflammation. In this study, TLMPs induced IL-1β and IL-18 secretion through NLRP3 inflammasome activation and upregulated TLR4 mRNA and protein expression in alveolar (A549) and human airway epithelial (16HBE) cells. Pretreatment with CLI-095, a specific inhibitor of TLR4 signaling, dramatically diminished the TLMP-induced release of IL-1β and IL-18 by inhibiting the formation of NLRP3/ASC/pro-caspase-1 inflammasome in a dose-dependent manner. The TLMP-induced autophagy inhibition in epithelial cells was dependent on the PI3K/Akt signaling pathway, which significantly increased NLRP3 expression and enhanced TLMP-induced inflammation. TLR4, IL-1β, and IL-18 proteins harbored in TLMPs were nonessential for the pro-inflammatory effect. In conclusion, TLMPs induce bronchial and alveolar epithelial cell secretion of IL-1β and IL-18 cytokines by activating the TLR4 and PI3K/Akt signaling pathways and inhibiting autophagy. These effects lead to NLRP3 inflammasome formation and accumulation. TLMPs may be regarded as deleterious markers of airway and lung damage in respiratory diseases.

Effects of Microvesicles on Cell Apoptosis under Hypoxia

Hypoxia, as one of the severe cellular stresses, can cause cellular injury and even cell death. Apoptosis is the main mechanism of regulating cell death and is closely related to the cell death caused by hypoxia. However, hypoxia-induced apoptosis is not entirely the result of direct hypoxic stimulus of cells. In recent years, it has been found that cells injured by hypoxia can shed a kind of membranous vesicles, which are called microvesicles (MVs). MVs can carry bioactive molecules from injured mother cells and appear in blood, cerebrospinal fluid, and other body fluids. MVs can induce normal cell apoptosis by transferring bioactive molecules into adjacent cells and amplifying the hypoxic injury in an organism. This review summarizes the characteristic changes of MVs derived from hypoxic cells and the mechanism of normal cell apoptosis mediated by hypoxic cell-derived MVs. Finally, we introduce the significance of this apoptosis-apoptosis cascade reaction in hypoxic diseases.

Large Extracellular Vesicles: Have We Found the Holy Grail of Inflammation?

The terms microparticles (MPs) and microvesicles (MVs) refer to large extracellular vesicles (EVs) generated from a broad spectrum of cells upon its activation or death by apoptosis. The unique surface antigens of MPs/MVs allow for the identification of their cellular origin as well as its functional characterization. Two basic aspects of MP/MV functions in physiology and pathological conditions are widely considered. Firstly, it has become evident that large EVs have strong procoagulant properties. Secondly, experimental and clinical studies have shown that MPs/MVs play a crucial role in the pathophysiology of inflammation-associated disorders. A cardinal feature of these disorders is an enhanced generation of platelets-, endothelial-, and leukocyte-derived EVs. Nevertheless, anti-inflammatory effects of miscellaneous EV types have also been described, which provided important new insights into the large EV-inflammation axis. Advances in understanding the biology of MPs/MVs have led to the preparation of this review article aimed at discussing the association between large EVs and inflammation, depending on their cellular origin.

Increasing complexity and interactions of oxidative stress in chronic respiratory diseases: An emerging need for novel drug delivery systems

Oxidative stress is intensely involved in enhancing the severity of various chronic respiratory diseases (CRDs) including asthma, chronic obstructive pulmonary disease (COPD), infections and lung cancer. Even though there are various existing anti-inflammatory therapies, which are not enough to control the inflammation caused due to various contributing factors such as anti-inflammatory genes and antioxidant enzymes. This leads to an urgent need of novel drug delivery systems to combat the oxidative stress. This review gives a brief insight into the biological factors involved in causing oxidative stress, one of the emerging hallmark feature in CRDs and particularly, highlighting recent trends in various novel drug delivery carriers including microparticles, microemulsions, microspheres, nanoparticles, liposomes, dendrimers, solid lipid nanocarriers etc which can help in combating the oxidative stress in CRDs and ultimately reducing the disease burden and improving the quality of life with CRDs patients. These carriers improve the pharmacokinetics and bioavailability to the target site. However, there is an urgent need for translational studies to validate the drug delivery carriers for clinical administration in the pulmonary clinic.

The role of reactive oxygen intermediates in the intracellular fate of Leptospira interrogans in the macrophages of different hosts

Background

Pathogenic species of Leptospira cause leptospirosis, a global zoonotic disease. Our previous work showed that leptospires survive and replicate in human macrophages but are killed in murine macrophages. However, the mechanism responsible for the different intracellular fates of leptospires within the macrophages of different hosts remains unclear.

Results

The present study demonstrates that infection with Leptospira interrogans caused significant up-regulation of reactive oxygen species (ROS) and superoxide in J774A.1 cells but did so to a lesser extent in THP-1 cells. The up-regulation of ROS and superoxide was significantly inhibited by the NADPH oxidase inhibitor apocynin. The damaged leptospires and remnants of leptospires within membrane-bound vacuoles were significantly inhibited by apocynin in J774A.1 cells but were less inhibited in THP-1 cells. In addition, apocynin significantly prevented damage to leptospires and the co-localization of L. interrogans with lysosomes in J774A.1 cells but did so to a lesser extent in THP-1 cells. Furthermore, the relative fluorescence intensity levels of intracellular leptospires and the viability of the intracellular leptospires increased in apocynin pretreated J774A.1 and THP-1 cells after 2 h of infection.

Conclusions

The present study, based on our previous findings, further demonstrated that ROS contributed substantially to the bactericidal ability of mouse macrophages to kill intracellular leptospires. However, ROS did not contribute as much in human macrophages, which partially explains the different intracellular fates of L. interrogans in human and mouse macrophages.

Lymphocytic Microparticles Modulate Angiogenic Properties of Macrophages in Laser-induced Choroidal Neovascularization

Pathological choroidal neovascularization (CNV) is the common cause of vision loss in patients with age-related macular degeneration (AMD). Macrophages possess potential angiogenic function in CNV. We have demonstrated that human T lymphocyte-derived microparticles (LMPs) exert a potent antiangiogenic effect in several pathological neovascularization models. In this study, we investigated the alteration of proangiogenic properties of macrophages by LMPs treatment in vitro and in vivo models. LMPs regulated the expression of several angiogenesis-related factors in macrophages and consequently stimulated their antiangiogenic effects evidenced by the suppression of the proliferation of human retinal endothelial cells in co-culture experiments. The involvement of CD36 receptor in LMPs uptake by macrophages was demonstrated by in vitro assays and by immunostaining of choroidal flat mounts. In addition, ex vivo experiments showed that CD36 mediates the antiangiogenic effect of LMPs in murine and human choroidal explants. Furthermore, intravitreal injection of LMPs in the mouse model of laser-induced CNV significantly suppressed CNV in CD36 dependent manner. The results of this study suggested an ability of LMPs to alter the gene expression pattern of angiogenesis-related factors in macrophages, which provide important information for a new therapeutic approach for efficiently interfering with both vascular and extravascular components of CNV.

Competitive colonization of prosthetic surfaces by staphylococcus aureus and human cells

Implantation of a biomaterial provides an adhesion substratum both to host cell integration and to contaminating bacteria. We studied simultaneous competitive adhesion of Staphylococcus aureus in serial 1:10 dilutions of 10⁸ colony forming units (CFU)/mL and human osteogenic sarcoma (SaOS-2) or primary osteoblast (hOB) cells, both 1x10⁵ cells/mL, to the surfaces of titanium, polydimethylsiloxane and polystyrene. The bacterial adherence and human cell proliferation, cytotoxicity and production of reactive oxygen species (ROS) were studied using fluorometric (fluorescent microscopy and flow cytometry) and colorimetric methods (MTT, LDH and crystal violet). The bacterial cell viability was also evaluated using the drop plate method. The presence of bacteria resulted in reduced adherence of human cells to the surface of the biomaterials, increased production of ROS, and into increased apoptosis. On the other hand, the presence of either type of human cells was associated with a reduction of bacterial colonization of the biomaterial with Staphylococcus aureus. These results suggest that increasing colonization of the biomaterial surface in vitro by one negatively affects colonization by the other. Host cell integration to an implant surface reduces bacterial contamination, which opens novel opportunities for the design of infection-resistant biomaterials in current implantology and future regenerative medicine. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 62-72, 2017.

Microvesicles in Autoimmune Diseases

During apoptosis or activation, cells can release a subcellular structure, called a membrane microvesicle (also known as microparticle) into the extracellular environment. Microvesicles bud-off as a portion of cell membrane with its associated proteins and lipids surrounding a cytosolic core that contains intracellular proteins, lipids, and nucleic acids (DNA, RNA, siRNA, microRNA, lncRNA). Biologically active molecules on the microvesicle surface and encapsulated within can act on recipient cells as a novel mode of intercellular communication. Apoptosis has long been known to be involved in the development of diseases of autoimmunity. Abnormally persistent microvesicles, particularly apoptotic microvesicles, can accelerate autoimmune responses locally in specific organs and tissues as well as systemically. In this review, we focus on studies implicating microvesicles in the pathogenesis of autoimmune diseases and their complications.

Uncoupling Protein 2 Increases Susceptibility to Lipopolysaccharide-Induced Acute Lung Injury in Mice

Uncoupling protein 2 (UCP2) is upregulated in patients with systemic inflammation and infection, but its functional role is unclear. We up- or downregulated UCP2 expression using UCP2 recombinant adenovirus or the UCP2 inhibitor, genipin, in lungs of mice, and investigated the mechanisms of UCP2 in ALI. UCP2 overexpression in mouse lungs increased LPS-induced pathological changes, lung permeability, lung inflammation, and lowered survival rates. Furthermore, ATP levels and mitochondrial membrane potential were decreased, while reactive oxygen species production was increased. Additionally, mitogen-activated protein kinases (MAPKs) activity was elevated, which increased the sensitivity to LPS-induced apoptosis and inflammation. LPS-induced apoptosis and release of inflammatory factors were alleviated by pretreatment of the Jun N-terminal kinase (JNK) inhibitor SP600125 or the p38 MAPK inhibitor SB203580, but not by the extracellular signal-regulated kinase (ERK) inhibitor PD98059 in UCP2-overexpressing mice. On the other hand, LPS-induced alveolar epithelial cell death and inflammation were attenuated by genipin. In conclusion, UCP2 increased susceptibility to LPS-induced cell death and pulmonary inflammation, most likely via ATP depletion and activation of MAPK signaling following ALI in mice.

Investigating the potential of Shikonin as a novel hypertrophic scar treatment

Background

Hypertrophic scarring is a highly prevalent condition clinically and results from a decreased number of apoptotic fibroblasts and over-abundant production of collagen during scar formation following wound healing. Our previous studies indicated that Shikonin, an active component extracted from Radix Arnebiae, induces apoptosis and reduces collagen production in hypertrophic scar-derived fibroblasts. In the study reported here, we further evaluate the potential use of Shikonin as a novel scar remediation therapy by examining the effects of Shikonin on both keratinocytes and fibroblasts using Transwell® co-culture techniques. The underlying mechanisms were also revealed. In addition, effects of Shikonin on the expression of cytokines in Transwell co-culture “conditioned” medium were investigated.

Results

Our results indicate that Shikonin preferentially inhibits cell proliferation and induces apoptosis in fibroblasts without affecting keratinocyte function. In addition, we found that the proliferation-inhibiting and apoptosis-inducing abilities of SHI might be triggered via MAPK and Bcl-2/Caspase 3 signalling pathways. Furthermore, SHI has been found to attenuate the expression of TGF-β1 in Transwell co-cultured “conditioned” medium.

Conclusions

The data generated from this study provides further evidence that supports the potential use of Shikonin as a novel scar remediation therapy.

P2X7 receptor is critical in α-synuclein--mediated microglial NADPH oxidase activation

Activated microglia are commonly observed in individuals with neurodegenerative disorders, including Parkinson's disease (PD) and are believed to contribute to neuronal death. This process occurs at least due partially to nicotinamide adenine dinucleotide phosphate oxidase (PHOX) activation, which leads to the production of superoxide and oxidative stress. α-Synuclein (α-Syn), a key protein implicated in PD pathogenesis, can activate microglia, contributing to death of dopaminergic neurons. Here, microglial cells (BV2) and primary cultured microglia were used to study the role that the purinergic receptor P2X7 plays in recognizing α-Syn and promoting PHOX activation. We demonstrate that both wild type and A53T mutant α-Syn readily activate PHOX, with the A53T form producing more rapid and sustained effects,that is, oxidative stress and cellular injuries. Furthermore, this process involves the activation of phosphoinositide 3-kinase (PI3K)/AKT (protein kinase B) pathway. Thus, it is concluded that stimulation of the microglial P2X7 receptor by extracellular α-Syn, with PI3K/AKT activation and increased oxidative stress, could be an important mechanism and a potential therapeutic target for PD.