Search results for "Acellular"

Mitochondrial CB1 receptors regulate neuronal energy metabolism

2012

The mammalian brain is one of the organs with the highest energy demands, and mitochondria are key determinants of its functions. Here we show that the type-1 cannabinoid receptor (CB(1)) is present at the membranes of mouse neuronal mitochondria (mtCB(1)), where it directly controls cellular respiration and energy production. Through activation of mtCB(1) receptors, exogenous cannabinoids and in situ endocannabinoids decreased cyclic AMP concentration, protein kinase A activity, complex I enzymatic activity and respiration in neuronal mitochondria. In addition, intracellular CB(1) receptors and mitochondrial mechanisms contributed to endocannabinoid-dependent depolarization-induced suppres…

Atomistic Simulations of Functional Gold Nanoparticles Au144(Sr)60 Interacting with Membranes

2013

Gold nanoparticles (AuNps) are used in nanomedicine in, e.g., drug delivery and bio-imaging. However, it is regrettable that the understanding of nanoparticle properties in cellular surroundings is incompletely understood. Here, we have complemented our previous studies [1] by performing extensive atomistic molecular dynamics simulations of lipid membranes interacting with charged gold nanoparticles. We have elucidated the action of these nanoparticles on membranes characterized by lipid compositional asymmetry in the two leaflets, thereby unraveling the interactions of AuNPs with both the extracellular and the cytosolic sides of plasma membranes of eukaryotic cells. We have found that ther…

Centrosome amplification mediates small extracellular vesicles secretion via lysosome disruption

2020

SummaryBidirectional communication between cells and their surrounding environment is critical in both normal and pathological settings. Extracellular vesicles (EVs), which facilitate the horizontal transfer of molecules between cells, are recognized as an important constituent of cell-cell communication. In cancer, alterations in EV secretion contribute to the growth and metastasis of tumor cells. However, the mechanisms underlying these changes remain largely unknown. Here, we show that centrosome amplification is associated with and sufficient to promote small extracellular vesicle (SEV) secretion in pancreatic cancer cells. This is a direct result due of lysosomal dysfunction, caused by…

Effect of Combined Physical Stresses on Cells: The Role of Water

2010

International audience; The role of water in microorganism viability was assessed through the application of combined physical perturbations. The combination of different physical parameters could allow to balance the properties variations (especially water related) resulting from the increase of one parameter alone. Thus, it is possible to optimize the survival of cells in controlling these parameters. This was tested through two different examples. The first example shows that combination of osmotic level and temperature can allow optimizing yeast cell survival in following membrane fluidity variation. Moreover this analysis has allowed a better comprehension of cell inactivation during r…

Advanced mechanotherapy: Biotensegrity  for governing metastatic tumor cell fate via modulating the extracellular matrix.

2021

Mechano-transduction is the procedure of mechanical stimulus translation via cells, among substrate shear flow, topography, and stiffness into a biochemical answer. TAZ and YAP are transcriptional coactivators which are recognized as relay proteins that promote mechano-transduction within the Hippo pathway. With regard to healthy cells in homeostasis, mechano-transduction regularly restricts proliferation, and TAZ and YAP are totally inactive. During cancer development a YAP/TAZ - stimulating positive response loop is formed between the growing tumor and the stiffening ECM. As tumor developments, local stromal and cancerous cells take advantage of mechanotransduction to enhance proliferatio…

Gelatin‐Hyaluronan Click‐Crosslinked Cryogels Elucidate Human Macrophage Invasion Behavior

2021

Biomineralization toolkit: the importance of sample cleaning prior to the characterization of biomineral proteomes.

2013

In an interesting work published recently in PNAS, Drake et al. (1) presented a proteomic study of the skeleton from the stony coral Stylophora pistillata . This study identified proteins that are associated to the mineral phase (i.e., that potentially contribute to shape the skeleton). In other words, this set of proteins is supposed to represent the so-called “biomineralization toolkit.” Although some of the 36 proteins reported in Drake et al. (1) appear as genuine extracellular matrix (ECM) proteins related to biomineralization, such as coral acid-rich proteins or carbonic anhydrase, some others are obvious intracellular contaminants that should not be considered as skeletal organic mat…

Lewy body extracts from Parkinson disease brains trigger α-synuclein pathology and neurodegeneration in mice and monkeys

2014

Objective Mounting evidence suggests that α-synuclein, a major protein component of Lewy bodies (LB), may be responsible for initiating and spreading the pathological process in Parkinson disease (PD). Supporting this concept, intracerebral inoculation of synthetic recombinant α-synuclein fibrils can trigger α-synuclein pathology in mice. However, it remains uncertain whether the pathogenic effects of recombinant synthetic α-synuclein may apply to PD-linked pathological α-synuclein and occur in species closer to humans. Methods Nigral LB-enriched fractions containing pathological α-synuclein were purified from postmortem PD brains by sucrose gradient fractionation and subsequently inoculate…

Exosome levels in human body fluids: A tumor marker by themselves?

2016

Despite considerable research efforts, the finding of reliable tumor biomarkers remains challenging and unresolved. In recent years a novel diagnostic biomedical tool with high potential has been identified in extracellular nanovesicles or exosomes. They are released by the majority of the cells and contain detailed molecular information on the cell of origin including tumor hallmarks. Exosomes can be isolated from easy accessible body fluids, and most importantly, they can provide several biomarkers, with different levels of specificity. Recent clinical evidence shows that the levels of exosomes released into body fluids may themselves represent a predictive/diagnostic of tumors, discrimin…

Spray dried hyaluronic acid microparticles for adhesion controlled aggregation and potential stimulation of stem cells

2017

Spray-dried microparticles of a derivative of hyaluronic acid (HA) have been engineered to obtain a controlled aggregation with Human Mesenchymal Stem Cells (hMSCs) into 3D constructs. We demonstrated the utility of chemical functionalization of a native constituent of the extracellular matrix to improve processing performances and to control on stem cell adhesion and differentiation. Native hyaluronic acid (HA), cell adhesive peptides (RGD), transforming growth factor β3, dexamethasone are biological agents potentially suitable for chondrogenic stimulation of hMSCS. However unmodified HA suffers of drawbacks in terms of stability and versatility of processing. Functionalization strategies…