Effects of cell line proliferation on the aggregation and stability of a hyaluronic acid solution (HA)/PLGA microparticles dispersed in the culture system

Author(s):  
Silvia Locarno ◽  
Alessandra Galli ◽  
Simona Argentiere ◽  
Marta Galgano ◽  
Ilaria Giuntini ◽  
...  
1992 ◽  
Vol 287 (1) ◽  
pp. 255-259 ◽  
Author(s):  
M Hiron ◽  
M Daveau ◽  
P Arnaud ◽  
J Bauer ◽  
J P Lebreton

The regulation of the synthesis by the cytokines interleukin-1 (IL-1) and IL-6 of the positive acute-phase protein alpha 1-acid glycoprotein (AGP) and of the negative acute-phase protein alpha 2-HS glycoprotein (AHSG) has been studied in a long-term culture system of the human hepatoma cell line Hep3B. The culture system contained 30 nM-sodium selenite as the only supplement. This allowed maintenance of the synthesis of the proteins under study at a near steady state for over 3 months. An increase in AGP mRNA and a decrease in AHSG mRNA were observed when cells were treated for two successive 48 h-periods with monocyte-conditioned medium. A return to basal levels was obtained after cessation of the cytokine addition. Two further additions of cytokines led to alterations in mRNA levels similar to those observed following the first cytokine treatment. The amounts of AGP and AHSG secreted were altered in accordance with the mRNA modifications. These results suggest that new cytokine receptors were being constantly synthesized during cell culture. When cytokines were present in the culture medium for 10 days, maximum alterations in AGP and AHSG synthesis were obtained following 2 and 4 days of treatment respectively, but further alterations in protein levels could not be observed afterwards. Expression of IL-6 receptor mRNA was not up-regulated by cytokines, but only by 1 microM-dexamethasone. Our results show that, in this long-term culture system, cytokines induce a response in hepatoma cells similar to that observed in vivo during human inflammatory states. This model could be used to evaluate the effects of agonists or antagonists of cytokines responsible for the hepatic acute-phase protein response.


Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 78 ◽  
Author(s):  
Aleck H. Alexopoulos ◽  
Costas Kiparissides

The spreading of viscous and viscoelastic fluids on flat and curved surfaces is an important problem in many industrial and biomedical processes. In this work the spreading of a linear viscoelastic fluid with changing rheological properties over flat surfaces is investigated via a macroscopic model. The computational model is based on a macroscopic mathematical description of the gravitational, capillary, viscous, and elastic forces. The dynamics of droplet spreading are determined in sessile and pendant configurations for different droplet extrusion or formation times for a hyaluronic acid solution undergoing gelation. The computational model is employed to describe the spreading of hydrogel droplets for different extrusion times, droplet volumes, and surface/droplet configurations. The effect of extrusion time is shown to be significant in the rate and extent of spreading.


Blood ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 42-48 ◽  
Author(s):  
N Komatsu ◽  
T Suda ◽  
M Moroi ◽  
N Tokuyama ◽  
Y Sakata ◽  
...  

Abstract Recently, a human megakaryoblastic cell line, CMK, was established from the peripheral blood of a megakaryoblastic leukemia patient with Down syndrome. Using this cell line, we studied the proliferation and differentiation of megakaryocytic cells in the presence of highly purified human hematopoietic factors and phorbol 12-myristate-13- acetate (PMA). In a methylcellulose culture system, interleukin-3 (IL- 3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) facilitated colony formation by CMK cells in a dose-dependent manner. The maximum stimulating doses of these factors were 10 and 200 U/mL, respectively. These concentrations were comparable to those that stimulate activity in normal hematopoietic cells. In contrast, granulocyte-colony stimulating factor (G-CSF), macrophage-colony stimulating factor (M-CSF), and erythropoietin (EPO) had no effects on the colony formation of CMK cells. In a liquid culture system, 20% of the CMK cells expressed glycoprotein IIb/IIIa (GPIIb/IIIa) antigen without hematopoietic factors, whereas 40% of the cells expressed GPIIb/IIIa with the addition of IL-3 and GM-CSF. EPO also slightly enhanced expression of GPIIb/IIIa. On the other hand, PMA inhibited growth of CMK cells and induced most of them to express the GPIIb/IIIa antigen. Furthermore, PMA induced CMK cells to produce growth activity toward new inocula of CMK cells. This growth factor (GF) contained colony-stimulating activity (CSA) in normal bone marrow (BM) cells. The activity was believed to be attributable mainly to GM-CSF, since 64% of this activity was neutralized by anti-GM-CSF antibodies and a transcript of GM-CSF was detected in mRNA from PMA-treated CMK cells by Northern blot analysis. These observations suggest that GM-CSF, as well as IL-3, should play an important role in megakaryocytopoiesis.


2020 ◽  
pp. 030089162095287
Author(s):  
Shiqin Zheng ◽  
Yuxi Wei ◽  
Yu Jiang ◽  
Yi Hao

Purpose: Targeting programmed death-ligand 1 (PD-L1) may be an effective intervention for osteosarcoma and PD-L1 expression is controlled by diverse regulatory factors. Low-density lipoprotein receptor-related protein 8 (LRP8) regulates osteoblast differentiation and it is unclear whether and how LRP8 could contribute to osteosarcoma pathogenesis. In this study, we investigated the LRP8/signal transducer and activator of transcription 3 (STAT3)/PD-L1 network in osteosarcoma. Methods: The expression of LRP8, STAT3, and PD-L1 was measured in osteosarcoma tissues and paired normal tissues. The effects of LRP8 on STAT3 and PD-L1 expression were investigated in an osteosarcoma cell line. The effects on immunosuppression were investigated in an in vitro co-culture system with Jurkat cell line and osteosarcoma cell line. The effects of LRP8 were blocked by a LRP8 neutralizing antibody, dominant-negative STAT3, or STAT3 inhibitor. Results: LRP8 was overexpressed in osteosarcoma compared to normal tissues and its level was correlated with phospho-STAT3 (p-STAT3) level in osteosarcoma tissues. In osteosarcoma cell lines, LRP8 increased p-STAT3 level and promoted nuclear translocation of STAT3. STAT3 activation also increased PD-L1 mRNA, protein, and promoter activity. In addition, LRP8 enhanced PD-L1 expression via STAT3. In a co-culture system, LRP8 overexpression in an osteosarcoma cell line impaired viability and interleukin-2 secretion of Jurkat cells and induced apoptosis of Jurkat cells. The effects of LRP8 could be blocked by neutralizing LRP8 antibody or STAT3 inhibitor. Blocking LRP8 inhibits proliferation and induces apoptosis of osteosarcoma cells. Conclusions: Our results provide evidence for a novel regulation network of LRP8/STAT3/PD-L1 in osteosarcoma and LRP8 may be a potential therapeutic target in osteosarcoma.


Author(s):  
Masataka Yoshikawa ◽  
T. Yabuuchi ◽  
N. Tsuji ◽  
Y. Shimomura ◽  
H. Hayashi ◽  
...  

2003 ◽  
Vol 77 (3) ◽  
pp. 2134-2146 ◽  
Author(s):  
Vicky M.-H. Sung ◽  
Shigetaka Shimodaira ◽  
Alison L. Doughty ◽  
Gaston R. Picchio ◽  
Huong Can ◽  
...  

ABSTRACT Hepatitis C virus (HCV) is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Studies of HCV replication and pathogenesis have so far been hampered by the lack of an efficient tissue culture system for propagating HCV in vitro. Although HCV is primarily a hepatotropic virus, an increasing body of evidence suggests that HCV also replicates in extrahepatic tissues in natural infection. In this study, we established a B-cell line (SB) from an HCV-infected non-Hodgkin's B-cell lymphoma. HCV RNA and proteins were detectable by RNase protection assay and immunoblotting. The cell line continuously produces infectious HCV virions in culture. The virus particles produced from the culture had a buoyant density of 1.13 to 1.15 g/ml in sucrose and could infect primary human hepatocytes, peripheral blood mononuclear cells (PBMCs), and an established B-cell line (Raji cells) in vitro. The virus from SB cells belongs to genotype 2b. Single-stranded conformational polymorphism and sequence analysis of the viral RNA quasispecies indicated that the virus present in SB cells most likely originated from the patient's spleen and had an HCV RNA quasispecies pattern distinct from that in the serum. The virus production from the infected primary hepatocytes showed cyclic variations. In addition, we have succeeded in establishing several Epstein-Barr virus-immortalized B-cell lines from PBMCs of HCV-positive patients. Two of these cell lines are positive for HCV RNA as detected by reverse transcriptase PCR and for the nonstructural protein NS3 by immunofluorescence staining. These observations unequivocally establish that HCV infects B cells in vivo and in vitro. HCV-infected cell lines show significantly enhanced apoptosis. These B-cell lines provide a reproducible cell culture system for studying the complete replication cycle and biology of HCV infections.


2019 ◽  
Vol 35 (02) ◽  
pp. 119-124
Author(s):  
Sun-Min Kim ◽  
Chae-Won An ◽  
Jin-Hee Chang ◽  
Dong-Keon Kweon ◽  
Joo-Yeon Hong ◽  
...  

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