Search results for "XOS"

The role of lipid rafts in vesicle formation

2023

ABSTRACT The formation of membrane vesicles is a common feature in all eukaryotes. Lipid rafts are the best-studied example of membrane domains for both eukaryotes and prokaryotes, and their existence also is suggested in Archaea membranes. Lipid rafts are involved in the formation of transport vesicles, endocytic vesicles, exocytic vesicles, synaptic vesicles and extracellular vesicles, as well as enveloped viruses. Two mechanisms of how rafts are involved in vesicle formation have been proposed: first, that raft proteins and/or lipids located in lipid rafts associate with coat proteins that form a budding vesicle, and second, vesicle budding is triggered by enzymatic generation of cone-sh…

The Saccharomyces cerevisiae flavodoxin-like proteins Ycp4 and Rfs1 play a role in stress response and in the regulation of genes related to metaboli…

2011

SPI1 is a gene whose expression responds to many environmental stimuli, including entry into stationary phase. We have performed a screening to identify genes that activate SPI1 promoter when overexpressed. The phosphatidylinositol- 4-phosphate 5-kinase gene MSS4 was identified as a positive activator of SPI1. Another SPI1 transcriptional regulator isolated was the flavodoxin-like gene YCP4. YCP4 and its homolog RFS1 regulate the expression of many genes during the late stages of growth. The double deletion mutant in YCP4 and its homolog RFS1 has an impact on gene expression related to metabolism by increasing the expression of genes involved in hexose transport and glycolysis, and decreasi…

Extracellular vesicles in airway homeostasis and pathophysiology

2021

The epithelial–mesenchymal trophic unit (EMTU) is a morphofunctional entity involved in the maintenance of the homeostasis of airways as well as in the pathogenesis of several diseases, including asthma and chronic obstructive pulmonary disease (COPD). The “muco-microbiotic layer” (MML) is the innermost layer of airways made by microbiota elements (bacteria, viruses, archaea and fungi) and the surrounding mucous matrix. The MML homeostasis is also crucial for maintaining the healthy status of organs and its alteration is at the basis of airway disorders. Nanovesicles produced by EMTU and MML elements are probably the most important tool of communication among the different cell types, inclu…

Taxonomic notes on the genera Scatella and Scatophila (Diptera: Ephydridae) with a remark on Trixoscelis chilensis (Trixoscelididae).

2018

Two new combinations are proposed in Scatella for Ephydra australis Walker, 1853 and Opomyza guttata Macquart, 1843. Two species are resurrected from synonymy: Scatella lacustris (Meigen, 1830), revised status and Trixoscelis chilensis (Schiner, 1868), revised status (Trixoscelididae). Nine new synonyms are suggested: Scatella insularis Mathis & Wirth, 1981 = S. australis (Walker, 1853); S. lutosa nigripes Oldenberg, 1923 = S. obsoleta Loew, 1861; S. septempunctata Malloch, 1933 = S. gratiellae Canzoneri & Raffone, 1987 = S. septemfenestrata Lamb, 1912; S. tenuicosta Collin, 1930 = S. lacustris (Meigen, 1830); S. vulgata Cresson, 1931 = S. guttata (Macquart, 1843); Scatophila zlobin…

Abstract 5135: Exosomes released by K562 chronic myeloid leukemia cells promote endothelial cell tubular differentiation through uptake and cell-to-c…

2011

Abstract We hypothesized that exosomes were a venue through which to transfer pro-angiogenic stimuli into and between endothelial cells during endothelial cell tubular differentiation. Exosomes are microvesicles of endocytic origin released by most normal and tumor cells that play an important role in cell-to-cell communication. Angiogenesis is recognized to be a factor in progression of chronic myeloid leukemia (CML). However, the mechanism through which this happens has not been elucidated. We first optimized and characterized secretion of exosomes from CML K562 cells, showing expected selective enrichment of exosomal markers CD63, CD81 and Tsg101 in exosomes compared to the K562 whole ce…

Abstract 4372: Chronic myeloid leukemia (CML) exosomes promote angiogenesis in a Src-dependent fashion in vitro and in vivo

2012

Abstract CML is an uncontrolled proliferation of bone marrow myeloid cells driven by the constitutively active fusion product tyrosine kinase BCR/ABL. Angiogenesis, the formation of new blood vessels from pre-existing vasculature, is newly recognized as a factor in CML progression. Exosomes, released by a broad spectrum of cells, are microvesicles that play an important role in cell-to-cell communication both in physiological and pathological conditions. The role of exosomes released by CML cells in angiogenesis is emerging; however, little is known about the mechanisms involved in this process. We first isolated and characterized exosomes released by K562 CML cells and we demonstrated thei…

COLON CANCER CELL-DERIVED EXOSOMES INDUCE MACROPHAGES TO ACQUIRE AN IMMUNOSUPPRESSIVE PHENOTYPE BY UPREGULATING PD-L1 EXPRESSION

Tumor-associated macrophages (TAMs) are a prominent component of cancer microenvironment having a key role in promoting tumor progression. Several studies have demonstrated that TAMs phenotypically and functionally correspond to M2-polarized macrophages thus they exert immunosuppressive functions also associated to the expression of programmed cell death ligand 1 (PD-L1). Within the local tumor microenvironment, tumor-derived exosomes (TDEs) are well known to play a key role in modulating the properties and the behavior of surrounding cells such as TAMs. Even if several studies demonstrated the ability of TDEs to induce M2-like macrophage polarization, few data are available about their inv…

Transmission of Information in Neoplasia by Extracellular Vesicles.

2015

Paracrine interactions among neoplastic and nonneoplastic cells in the immediate tumor microenvironment are important for tumor growth and metastatic spreading. Most of the studies in the past decade addressing these cellular interactions have focused on tumor cell-derived soluble molecules. Recently, these studies and interest have shifted to nanosized extracellular vesicles (EVs) and especially ectosome and exosome-associated molecules [1]. They contain not only proteins, but also lipids, mRNA, and microRNA [1], which can regulate gene expression in their target cells in a much more pleiotropic manner [1]. While exosomes originate by a sequential process of inward budding of late endosome…

Hematologic malignancies: The exosome contribution in tumor progression

2020

Abstract The bone marrow, composed of cells, extracellular matrix, and soluble factors, such as cytokines, chemokines and signaling molecules, provides a favorable microenvironment for hematologic tumor progression and for the development of drug resistance. Recently, extracellular vesicles (EVs), released by tumor and surrounding cells, have emerged as important players within the bone marrow niche. Here we will discuss the current knowledge on the EV- mediated crosstalk between tumor and normal cells, in order to better understand how vesicles can contribute to tumor progression. Advances in the knowledge of the role of cell-derived EVs in tumor microenvironment highlight the possibility …

Exosomal Hsp60: A Tumor Biomarker?

2019

Exosomes (EXs) are extracellular vesicles containing proteins, DNA, mRNA, non-coding RNAs, such as miRNAs, and lipid. The EXs can be easily isolated from different biological fluids and their content is considered a potential biomarker in various diseases, such as cancer. EXs play an important role in intercellular communication, permitting cells to exchange proteins, lipids, and genetic material in normal and pathological conditions. New data have shown that tumor cells-derived EXs contribute to cancer progression through the modulation of tumor microenvironment. Heat shock proteins 60 kDa (Hsp60) is classically considered mitochondrial proteins with different biological roles. In recent y…