Extracellular vesicles (EVs) have emerged as important regulators of inter‐cellular and inter‐organ communication, in part via the transfer of their cargo to recipient cells. Although circulating EVs ...have been previously studied as biomarkers of aging, how circulating EVs change with age and the underlying mechanisms that contribute to these changes are poorly understood. Here, we demonstrate that aging has a profound effect on the circulating EV pool, as evidenced by changes in concentration, size, and cargo. Aging also alters particle function; treatment of cells with EV fractions isolated from old plasma reduces macrophage responses to lipopolysaccharide, increases phagocytosis, and reduces endothelial cell responses to vascular endothelial growth factor compared to cells treated with young EV fractions. Depletion studies indicate that CD63+ particles mediate these effects. Treatment of macrophages with EV‐like particles revealed that old particles increased the expression of EV miRNAs in recipient cells. Transfection of cells with microRNA mimics recapitulated some of the effects seen with old EV‐like particles. Investigation into the underlying mechanisms using bone marrow transplant studies revealed circulating cell age does not substantially affect the expression of aging‐associated circulating EV miRNAs in old mice. Instead, we show that cellular senescence contributes to changes in particle cargo and function. Notably, senolytic treatment of old mice shifted plasma particle cargo and function toward that of a younger phenotype. Collectively, these results demonstrate that senescent cells contribute to changes in plasma EVs with age and suggest a new mechanism by which senescent cells can affect cellular functions throughout the body.
Senescent cells accumulate in the body with aging and alter circulating extracellular vesicle microRNA content. This can be replicated in young mice by inducing senescence using sub‐lethal irradiation. Conversely, removal of senescent cells in aged mice by senolytic treatment restores circulating extracellular vesicle microRNA expression to that of a younger phenotype.
Ischemia‐reperfusion injury (IRI) and cardiac allograft vasculopathy (CAV) remain unsolved complications post–heart transplant (Tx). The antioxidant transcription factor Nuclear factor erythroid ...2‐related factor 2 (Nrf2) has been suggested to inhibit reactive oxygen species‐mediated NF‐κB activation. We hypothesized that Nrf2 inhibits NF‐κB activation post–Tx and suppresses IRI and the subsequent development of CAV. IRI and CAV were investigated in murine heterotopic Tx models, respectively. Nrf2 wild‐type (WT) and KO mice were used as donors. Sulforaphane was used as an Nrf2 agonist. In saline‐treated animals following 24 hours of reperfusion in isogenic grafts, Nrf2‐KO showed significantly less SOD1/2 activity compared with WT. Nrf2‐KO displayed significantly high total and phosphorylated p65 expressions and percentage of cells with nuclear p65. mRNA levels of NF‐κB‐mediated proinflammatory genes were also high. Graft dysfunction, apoptosis, and caspase‐3 activity were significantly higher in Nrf2‐KO. In the allograft studies, graft beating score was significantly weaker in Nrf2‐KO compared with WT. Nrf2‐KO also demonstrated significantly more coronary luminal narrowing. In WT animals, sulforaphane successfully augmented all the protective effects of Nrf2 with increase of SOD2 activity. Nrf2 inhibits NF‐κB activation and protects against IRI via its antioxidant properties and suppresses the subsequent development of CAV.
The antioxidant transcription factor nuclear factor erythroid 2–related factor 2 inhibits nuclear factor‐kappaB activation and protects against ischemia‐reperfusion injury via its antioxidant properties and suppresses the subsequent development of cardiac allograft vasculopathy.
Biofilms that contribute to the persistent bacterial infections pose serious threats to global public health, mainly due to their resistance to antibiotics penetration and escaping innate immune ...attacks by phagocytes. Here, we report a kind of surface-adaptive gold nanoparticles (AuNPs) exhibiting (1) a self-adaptive target to the acidic microenvironment of biofilm, (2) an enhanced photothermal ablation of methicillin-resistant Staphylococcus aureus (MRSA) biofilm under near-infrared (NIR) light irradiation, and (3) no damage to the healthy tissues around the biofilm. Originally, AuNPs were readily prepared by surface modification with pH-responsive mixed charged zwitterionic self-assembled monolayers consisting of weak electrolytic 11-mercaptoundecanoic acid (HS-C10-COOH) and strong electrolytic (10-mercaptodecyl)trimethylammonium bromide (HS-C10-N4). The mixed charged zwitterion-modified AuNPs showed fast pH-responsive transition from negative charge to positive charge, which enabled the AuNPs to disperse well in healthy tissues (pH ∼7.4), while quickly presenting strong adherence to negatively charged bacteria surfaces in MRSA biofilm (pH ∼5.5). Simultaneous AuNP aggregation within the MRSA biofilm enhanced the photothermal ablation of MRSA biofilm under NIR light irradiation. The surrounding healthy tissues showed no damage because the dispersed AuNPs had no photothermal effect under NIR light. In view of the above advantages as well as the straightforward preparation, AuNPs developed in this work may find potential applications as a useful antibacterial agent in the areas of healthcare.
Physical or mental stress leads to neuroplasticity in the brain and increases the risk of depression and anxiety. Stress exposure causes the dysfunction of peripheral T lymphocytes. However, the ...pathological role and underlying regulatory mechanism of peripheral T lymphocytes in mood disorders have not been well established. Here, we show that the lack of CD4+ T cells protects mice from stress-induced anxiety-like behavior. Physical stress-induced leukotriene B4 triggers severe mitochondrial fission in CD4+ T cells, which further leads to a variety of behavioral abnormalities including anxiety, depression, and social disorders. Metabolomic profiles and single-cell transcriptome reveal that CD4+ T cell-derived xanthine acts on oligodendrocytes in the left amygdala via adenosine receptor A1. Mitochondrial fission promotes the de novo synthesis of purine via interferon regulatory factor 1 accumulation in CD4+ T cells. Our study implicates a critical link between a purine metabolic disorder in CD4+ T cells and stress-driven anxiety-like behavior.
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•Peripheral CD4+ T cells control stress-induced anxiety-like behavior•Mitochondrial fission in peripheral CD4+ T cell causes severe anxiety symptoms•T cell-derived xanthine acts on the oligodendrocytes in the left amygdala•IRF-1 controls purine synthesis in CD4+ T cells and triggers the onset of anxiety
Xanthine metabolism in CD4+ T cells is found to be central to mediating the effects of stress-induced anxiety like behavior in mice through its effects on oligodendrocyte proliferation and neuronal hyperactivation.
Quercetin is a potent cancer therapeutic agent and dietary antioxidant present in fruit and vegetables. Quercetin prevents tumor proliferation by inducing cell cycle arrest and is a well known cancer ...therapeutic agent and autophagy mediator. Recent studies showed that drug delivery by nanoparticles have enhanced efficacy with reduced side effects. In this regard, gold-quercetin into poly(DL-lactide-co-glycolide) nanoparticles was examined. In this study, we explored the role and possible underlying mechanisms of quercetin nanoparticle in regulation of antitumor activity in liver cancer cells. Treatment with quercetin nanoparticle effectively inhibited the liver cancer cell proliferation, cell migration and colony formation, thus suppressing liver cancer progression. Quercetin nanoparticle also upregulated apoptosis markedly. Further study suggested that quercetin nanoparticle accelerated the cleavage of caspase-9, caspase-3, and induced the up-releasing of cytochrome c (Cyto-c), contributing to apoptosis in liver cancer cells. Quercetin nanoparticles also promoted telomerase reverse transcriptase (hTERT) inhibition through reducing AP-2β expression and decreasing its binding to hTERT promoter. In addition, quercetin nanoparticle had an inhibitory role in cyclooxygenase 2 (COX-2) via suppressing the NF-κB nuclear translocation and its binding to COX-2 promoter. Quercetin nanoparticle also inactivated Akt and ERK1/2 signaling pathway. Taken together, our results suggested that quercetin nanoparticle had an antitumor effect by inactivating caspase/Cyto-c pathway, suppressing AP-2β/hTERT, inhibiting NF-κB/COX-2 and impeding Akt/ERK1/2 signaling pathways. Our results provided new mechanistic basis for further investigation of quercetin nanoparticles to find potential therapeutic strategies and possible targets for liver cancer inhibition.
The epicardium supports cardiomyocyte proliferation early in development and provides fibroblasts and vascular smooth muscle cells to the developing heart. The epicardium has been shown to play an ...important role during tissue remodeling after cardiac injury, making access to this cell lineage necessary for the study of regenerative medicine. Here we describe the generation of epicardial lineage cells from human pluripotent stem cells by stage-specific activation of the BMP and WNT signaling pathways. These cells display morphological characteristics and express markers of the epicardial lineage, including the transcription factors WT1 and TBX18 and the retinoic acid-producing enzyme ALDH1A2. When induced to undergo epithelial-to-mesenchymal transition, the cells give rise to populations that display characteristics of the fibroblast and vascular smooth muscle lineages. These findings identify BMP and WNT as key regulators of the epicardial lineage in vitro and provide a model for investigating epicardial function in human development and disease.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Despite great progress in engineering functional tissues for organ repair, including the heart, an invasive surgical approach is still required for their implantation. Here, we designed an elastic ...and microfabricated scaffold using a biodegradable polymer (poly(octamethylene maleate (anhydride) citrate)) for functional tissue delivery via injection. The scaffold's shape memory was due to the microfabricated lattice design. Scaffolds and cardiac patches (1 cm × 1 cm) were delivered through an orifice as small as 1 mm, recovering their initial shape following injection without affecting cardiomyocyte viability and function. In a subcutaneous syngeneic rat model, injection of cardiac patches was equivalent to open surgery when comparing vascularization, macrophage recruitment and cell survival. The patches significantly improved cardiac function following myocardial infarction in a rat, compared with the untreated controls. Successful minimally invasive delivery of human cell-derived patches to the epicardium, aorta and liver in a large-animal (porcine) model was achieved.
Synthetic scaffolds are needed for generating organized neo‐myocardium constructs to promote functional tissue repair. This study investigated the biocompatibility of an elastomeric electrospun ...degradable polar/hydrophobic/ionic polyurethane (D‐PHI) composite scaffold with human‐induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs). The composite material was electrospun to generate scaffolds, with nanofibres oriented in aligned or random directions. These features enabled the authors to evaluate the effect of characteristic elements which mimic that of the native extracellular matrix (alignment, chemical heterogeneity, and fiber topography) on hiPSC‐CMs activity. The functional nature of the hiPSC‐CM cultured on gelatin and Matrigel‐coated scaffolds were assessed, investigating the influence of protein interactions with the synthetic substrate on subsequent cell phenotype. After 7 days of culture, high hiPSC‐CM viability was observed on the scaffolds. The cells on the aligned scaffold were elongated and demonstrated aligned sarcomeres that oriented parallel to the direction of the fibers, while the cells on random scaffolds and a tissue culture polystyrene (TCPS) control did not exhibit such an organized morphology. The hiPSC‐CMs cultured on the scaffolds and TCPS expressed similar levels of cardiac troponin‐T, but there was a higher expression of ventricular myosin light chain‐2 on the D‐PHI composite scaffolds versus TCPS, indicating a higher proportion of hiPSC‐CM exhibiting a ventricular cardiomyocyte like phenotype. Within 7 days, the hiPSC‐CMs on aligned scaffolds and TCPS beat synchronously and had similar conductive velocities. These preliminary results show that aligned D‐PHI elastomeric scaffolds allow hiPSC‐CMs to demonstrate important cardiomyocytes characteristics, critical to enabling their future potential use for cardiac tissue regeneration.
Abstract The goal of cardiac tissue engineering is to restore function to the damaged myocardium with regenerative constructs. Human embryonic stem cell–derived cardiomyocytes (hESC-CMs) can produce ...viable, contractile, three-dimensional grafts that function in vivo . We sought to enhance the viability and functional maturation of cardiac tissue constructs by cyclical stretch. hESC-CMs seeded onto gelatin-based scaffolds underwent cyclical stretching. Histological analysis demonstrated a greater proportion of cardiac troponin T–expressing cells in stretched than non-stretched constructs, and flow sorting demonstrated a higher proportion of cardiomyocytes. Ultrastructural assessment showed that cells in stretched constructs had a more mature phenotype, characterized by greater cell elongation, increased gap junction expression, and better contractile elements. Real-time PCR revealed enhanced mRNA expression of genes associated with cardiac maturation as well as genes encoding cardiac ion channels. Calcium imaging confirmed that stretched constructs contracted more frequently, with shorter calcium cycle duration. Epicardial implantation of constructs onto ischemic rat hearts demonstrated the feasibility of this platform, with enhanced survival and engraftment of transplanted cells in the stretched constructs. This uniaxial stretching system may serve as a platform for the production of cardiac tissue-engineered constructs for translational applications.
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