Increased exosome secretion in neurons aging in vitro by NPC1-mediated endosomal cholesterol buildup

As neurons age, they show a decrease in their ability to degrade proteins and membranes. Because undegraded material is a source of toxic products, defects in degradation are associated with reduced cell function and survival. However, there are very few dead neurons in the aging brain, suggesting the action of compensatory mechanisms. We show in this work that ageing neurons in culture show large multivesicular bodies (MVBs) filled with intralumenal vesicles (ILVs) and secrete more small extracellular vesicles than younger neurons. We also show that the high number of ILVs is the consequence of the accumulation of cholesterol in MVBs, which in turn is due to decreased levels of the cholesterol extruding protein NPC1. NPC1 down-regulation is the consequence of a combination of upregulation of the NPC1 repressor microRNA 33, and increased degradation, due to Akt-mTOR targeting of NPC1 to the phagosome. Although releasing more exosomes can be beneficial to old neurons, other cells, neighbouring and distant, can be negatively affected by the waste material they contain.

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PBF, a proto-oncogene in esophageal carcinoma

Open Medicine ◽

10.1515/med-2019-0086 ◽

2019 ◽

Vol 14 (1) ◽

pp. 748-756

Author(s):

Shi-hai Lian ◽

Jun-ding Song ◽

Yi Huang

Keyword(s):

Cell Cycle ◽

Esophageal Carcinoma ◽

Cell Function ◽

Function Analysis ◽

Cell Phenotype ◽

Down Regulation ◽

Apoptosis Pathway ◽

Related Cell ◽

Rnai Technology

AbstractEmerging evidence shows that the pituitary tumour-transforming gene (PTTG)-binding factor (PBF) functions as a proto-oncogene in some tumors. However, the precise functions of PBF in tumorigenesis and its action mechanisms remain largely unknown. Here for the first time we demonstrated that PBF was associated with a tumor-related cell phenotype in esophageal carcinoma (ESCA) and identified the involved signaling pathways. PBF was up-regulated in ESCA tissues (Data from GEPIA) and cells. Then we down-regulated PBF in ESCA cell lines, Eca-109 and TE-1, by using RNAi technology. Cell function analysis suggested that down-regulation of PBF could inhibit tumor-related cell phenotypes, including proliferation, motility, apoptosis and cell cycle, in Eca-109 and TE-1 cells. Mechanism investigation suggested that apoptosis induced by PBF knockdown may be mediated by the activation of the mitochondrial apoptosis pathway and cell cycle arrest. AKT/mTOR and Wnt3a/β-catenin, key pathways in regulating tumor proliferation and metastasis, were found to be inactivated by the down-regulation of PBF in ESCA cells. In conclusion, our study demonstrates that PBF functions as a proto-oncogene in ESCA in vitro, which may be mediated through AKT/mTOR and Wnt3a/β-catenin pathways.

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Perilipin2 down-regulation in β cells impairs insulin secretion under nutritional stress and damages mitochondria

10.1101/2020.10.01.322974 ◽

2020 ◽

Author(s):

Akansha Mishra ◽

Siming Liu ◽

Joseph Promes ◽

Mikako Harata ◽

William Sivitz ◽

...

Keyword(s):

Insulin Secretion ◽

Cell Function ◽

Islet Cells ◽

Cell Metabolism ◽

Nutritional Stress ◽

Β Cells ◽

Β Cell ◽

Down Regulation

Perilipin 2 (PLIN2) is the lipid droplet (LD) protein in β cells that increases under nutritional stress. Down-regulation of PLIN2 is often sufficient to reduce LD accumulation. To determine whether PLIN2 positively or negatively affects β cell function under nutritional stress, PLIN2 was down-regulated in mouse β cells, INS1 cells, and human islet cells. β cell specific deletion of PLIN2 in mice on a high fat diet reduced glucose-stimulated insulin secretion (GSIS) in vivo and in vitro. Down-regulation of PLIN2 in INS1 cells blunted GSIS after 24 h incubation with 0.2 mM palmitic acids. Down-regulation of PLIN2 in human pseudoislets cultured at 5.6 mM glucose impaired both phases of GSIS, indicating that PLIN2 is critical for GSIS. Down-regulation of PLIN2 decreased specific OXPHOS proteins in all three models and reduced oxygen consumption rates in INS1 cells and mouse islets. Moreover, we found that PLIN2 deficient INS1 cells increased the distribution of a fluorescent oleic acid analog to mitochondria and showed signs of mitochondrial stress as indicated by susceptibility to fragmentation and alterations of acyl-carnitines and glucose metabolites. Collectively, PLIN2 in β cells have an important role in preserving insulin secretion, β cell metabolism and mitochondrial function under nutritional stress.

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Down-regulation of LncRNA 2900052N01Rik inhibits LPS-induced B cell function in vitro

Cellular Immunology ◽

10.1016/j.cellimm.2021.104321 ◽

2021 ◽

pp. 104321

Author(s):

Faming Wang ◽

Yao Luo ◽

Le Zhang ◽

Muhammad Younis ◽

Liudi Yuan

Keyword(s):

B Cell ◽

Cell Function ◽

Down Regulation ◽

B Cell Function

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Bortezomib Down-Regulates HLA Class I and Enhances Natural Killer Cell Mediated Lysis of Myeloma.

Blood ◽

10.1182/blood.v108.11.3498.3498 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3498-3498

Author(s):

Jumei Shi ◽

Tarun K. Garg ◽

Rachel E. Kellum ◽

Susann M. Szmania ◽

Bart Barlogie ◽

...

Keyword(s):

Natural Killer ◽

Cell Function ◽

Nk Cell ◽

Treated Patient ◽

Hla Class I ◽

Class I ◽

Down Regulation ◽

Myeloma Cells ◽

Bortezomib Treatment

Abstract Introduction: Immunotherapy with Natural Killer (NK) cells may eradicate residual chemotherapy-resistant myeloma (MM) after a state of minimal residual disease has been achieved by autologous stem cell supported high-dose chemotherapy. NK cell activity is regulated by Killer Immunoglobulin-Like Receptors (KIRs). The principal inhibitory ligands of KIRs are HLA Class I molecules (-C and -Bw4) expressed by target cells. NK cells lyse tumor cells that do not display such inhibitory KIR-ligands (KIR-L), such as the K562 cell line. The proteasome is responsible for the generation of peptides that bind to and stabilize Class I molecules at the cell surface. We hypothesized that treatment of MM cells with the proteasome inhibitor bortezomib results in the down-regulation of Class I and thereby sensitizes MM to NK cell mediated lysis. Methods: MM cell lines and primary MM cells were treated with concentrations of bortezomib easily achievable in vivo. The objectives were to determine a) the optimal concentration of bortezomib to down-regulate Class I, b) the time to maximum down-regulation of Class I, and c) a bortezomib concentration that increases NK-mediated MM killing without affecting NK cell function. Results: We found that down-regulation of Class I post-bortezomib treatment of the MM cell line, JJN3, and primary MM cells was dose and time dependent. Bortezomib at 10–20nM down-regulated HLA-class I by 63% compared to untreated control cells with maximal down-regulation at 24hrs (Fig.1a). Bortezomib treatment of primary MM cells greatly increased sensitivity to NK cell-mediated lysis, compared to controls (6% vs. 61%) at an E:T ratio of 20:1 (Fig.1b). These bortezomib concentrations did not affect NK cell function. Conclusions: We observed that bortezomib down-regulates Class I and enhances the sensitivity of MM to NK cell-mediated lysis. Our findings have clear therapeutic implications for MM and other NK cell-sensitive malignancies. Figure 1a. Bortezomib down-regulates HLA-class I expression on patient myeloma cells. Figure 1a. Bortezomib down-regulates HLA-class I expression on patient myeloma cells. Figure 1b. Increased killing of bortezomib-treated patient myeloma by NK in vitro. Figure 1b. Increased killing of bortezomib-treated patient myeloma by NK in vitro.

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Extracellular vesicles released by the human gut symbiont Bacteroides thetaiotaomicron in the mouse intestine are enriched in a selected range of proteins that influence host cell physiology and metabolism

10.21203/rs.3.rs-124947/v1 ◽

2020 ◽

Author(s):

Regis Stentz ◽

Udo Wegmann ◽

Maria Guirro ◽

Will Bryant ◽

Avani Ranjit ◽

...

Keyword(s):

Host Cell ◽

Extracellular Vesicles ◽

Cell Function ◽

Bile Salt Hydrolase ◽

Cell Physiology ◽

Bacteroides Thetaiotaomicron ◽

Human Gut ◽

The Impact

Abstract It is becoming increasingly clear that bacterial extracellular vesicles (BEVs) produced by members of the intestinal microbiota can contribute to microbe-host cell interactions that impact on host health. A major unresolved question is the nature of the cargo packaged into these BEVs and how they can impact on host cell function. Here we have analysed the proteome of BEVs produced by the major human gut symbiont Bacteroides thetaiotaomicron in both in vitro cultures using defined and complex medias, and in vivo in fed or fasted animals to determine the impact of nutrient stress on the BEV proteome, and to identify proteins specifically enriched in BEVs produced in vivo. In contrast to BEVs produced in vitro where limiting nutrient provision resulted in an increase in a large fraction of proteins, the protein content of BEVs extracted from fasted versus fed mice was less affected with similar numbers of proteins showing increased and decreased abundance. We identified 102 proteins exclusively enriched in BEVs in vivo of which the majority (66/102) were enriched independently of their expression in the parent cells implicating the existence of an active mechanism to drive the selection of a group of proteins for their secretion into BEVs within the intestine. Amongst these abundantly expressed proteins in BEVs in vivo were a bile salt hydrolase and a dipeptidyl peptidase IV that were characterised further and shown to be active and able to degrade host-derived substrates with defined roles in metabolism. Collectively these findings provide additional evidence for the role of BEVs in microbiota-host interactions with their contents playing key roles in the maintenance of intestinal homeostasis, and host metabolism.

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Down regulation of osteopontin interferes with HCV replication by inhibition of WNT signalling in vitro

Zeitschrift für Gastroenterologie ◽

10.1055/s-0032-1332151 ◽

2013 ◽

Vol 51 (01) ◽

Author(s):

C Loscher ◽

R Bartenschlager ◽

V Lohmann ◽

G Tiegs ◽

G Sass

Keyword(s):

Wnt Signalling ◽

Down Regulation

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Control of Adult Stem Cell Function in Bioengineered in vitro Niches

10.1557/proc-1140-hh07-07 ◽

2008 ◽

Author(s):

Helen M. Blau ◽

Matthias P. Lutolf

Keyword(s):

Stem Cell ◽

Cell Function ◽

Adult Stem Cell

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Role of 4-O Galloylchlorogenic Acid in Lung Cancer- An Insilico Approach

International Journal of Pharmaceutical and Clinical Research ◽

10.25258/ijpcr.v9i5.8595 ◽

2017 ◽

Vol 9 (5) ◽

Author(s):

Jaynthy C. ◽

N. Premjanu ◽

Abhinav Srivastava

Keyword(s):

Lung Cancer ◽

Cell Proliferation ◽

In Silico ◽

Computational Study ◽

Regulation Mechanism ◽

Down Regulation ◽

Fruit Extract ◽

In Vitro Techniques ◽

Discovery Studio

Cancer is a major disease with millions of patients diagnosed each year with high mortality around the world. Various studies are still going on to study the further mechanisms and pathways of the cancer cell proliferation. Fucosylation is one of the most important oligosaccharide modifications involved in cancer and inflammation. In cancer development increased core fucosylation by FUT8 play an important role in cell proliferation. Down regulation of FUT8 expression may help cure lung cancer. Therefore the computational study based on the down regulation mechanism of FUT8 was mechanised. Sapota fruit extract, containing 4-Ogalloylchlorogenic acid was used as the inhibitor against FUT-8 as target and docking was performed using in-silico tool, Accelrys Discovery Studio. There were several conformations of the docked result, and conformation 1 showed 80% dock score between the ligand and the target. Further the amino acids of the inhibitor involved in docking were studied using another tool, Ligplot. Thus, in-silico analysis based on drug designing parameters shows that the fruit extract can be studied further using in-vitro techniques to know its pharmacokinetics.

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