Membrane Microdomains

Publication Title: 
PloS One

Artemisinin and its main active metabolite dihydroartemisinin, clinically used antimalarial agents with low host toxicity, have recently shown potent anticancer activities in a variety of human cancer models. Although iron mediated oxidative damage is involved, the mechanisms underlying these activities remain unclear. In the current study, we found that dihydroartemisinin caused cellular iron depletion in time- and concentration-dependent manners. It decreased iron uptake and disturbed iron homeostasis in cancer cells, which were independent of oxidative damage.

Author(s): 
Ba, Qian
Zhou, Naiyuan
Duan, Juan
Chen, Tao
Hao, Miao
Yang, Xinying
Li, Junyang
Yin, Jun
Chu, Ruiai
Wang, Hui
Publication Title: 
Cancer Research

Cell adhesion and spreading is a crucial step in the metastatic cascade of cancer cells, and interruption of this step is considered to be a logical strategy for prevention and treatment of tumor metastasis. Emodin is the major active component of the rhizome of Rheum palmatum L., with known anticancer activities. Here, we first found that emodin significantly inhibited cell adhesion of various human cancer cells.

Author(s): 
Huang, Qing
Shen, Han-Ming
Shui, Guanghou
Wenk, Markus R.
Ong, Choon-nam
Publication Title: 
The Journal of Biological Chemistry

Macrophage-specific Abca1 knock-out (Abca1(-)(M)(/-)(M)) mice were generated to determine the role of macrophage ABCA1 expression in plasma lipoprotein concentrations and the innate immune response of macrophages. Plasma lipid and lipoprotein concentrations in chow-fed Abca1(-)(M)(/-)(M) and wild-type (WT) mice were indistinguishable.

Author(s): 
Zhu, Xuewei
Lee, Ji-Young
Timmins, Jenelle M.
Brown, J. Mark
Boudyguina, Elena
Mulya, Anny
Gebre, Abraham K.
Willingham, Mark C.
Hiltbold, Elizabeth M.
Mishra, Nilamadhab
Maeda, Nobuyo
Parks, John S.
Publication Title: 
AIDS research and human retroviruses

The high rate of HIV-1 mutation and the frequent sexual transmission highlight the need for novel therapeutic modalities with broad activity against both CXCR4 (X4) and CCR5 (R5)-tropic viruses. We investigated a large number of natural products, and from Sargassum fusiforme we isolated and identified palmitic acid (PA) as a natural small bioactive molecule with activity against HIV-1 infection. Treatment with 100 microM PA inhibited both X4 and R5 independent infection in the T cell line up to 70%.

Author(s): 
Lee, David Y.-W.
Lin, Xudong
Paskaleva, Elena E.
Liu, Yanze
Puttamadappa, Shadakshara S.
Thornber, Carol
Drake, James R.
Habulin, Maja
Shekhtman, Alexander
Canki, Mario
Publication Title: 
The Biochemical Journal

IbeA in meningitic Escherichia coli K1 strains has been described previously for its role in invasion of BMECs (brain microvascular endothelial cells). Vimentin was identified as an IbeA-binding protein on the surface of HBMECs (human BMECs). In the present study, we demonstrated that vimentin is a primary receptor required for IbeA+ E. coli K1-induced signalling and invasion of HBMECs, on the basis of the following observations. First, E44 (IbeA+ E.

Author(s): 
Chi, Feng
Jong, Timothy D.
Wang, Lin
Ouyang, Yannan
Wu, Chunhua
Li, Wei
Huang, Sheng-He
Publication Title: 
Journal of Lipid Research

We previously showed that macrophages from macrophage-specific ATP-binding cassette transporter A1 (ABCA1) knockout (Abca1(-M/-M)) mice had an enhanced proinflammatory response to the Toll-like receptor (TLR) 4 agonist, lipopolysaccharide (LPS), compared with wild-type (WT) mice. In the present study, we demonstrate a direct association between free cholesterol (FC), lipid raft content, and hyper-responsiveness of macrophages to LPS in WT mice. Abca1(-M/-M) macrophages were also hyper-responsive to specific agonists to TLR2, TLR7, and TLR9, but not TLR3, compared with WT macrophages.

Author(s): 
Zhu, Xuewei
Owen, John S.
Wilson, Martha D.
Li, Haitao
Griffiths, Gary L.
Thomas, Michael J.
Hiltbold, Elizabeth M.
Fessler, Michael B.
Parks, John S.
Publication Title: 
The Journal of Nutrition

Model membrane and cellular detergent extraction studies show (n-3) PUFA predominately incorporate into nonrafts; thus, we hypothesized (n-3) PUFA could disrupt nonraft organization. The first objective of this study was to determine whether (n-3) PUFA disrupted nonrafts of EL4 cells, an extension of our previous work in which we discovered an (n-3) PUFA diminished raft clustering.

Author(s): 
Rockett, Benjamin Drew
Franklin, Andrew
Harris, Mitchel
Teague, Heather
Rockett, Alexis
Shaikh, Saame Raza
Publication Title: 
Diabetologia

AIMS/HYPOTHESIS: Diminished cortical filamentous actin (F-actin) has been implicated in skeletal muscle insulin resistance, yet the mechanism(s) is unknown. Here we tested the hypothesis that changes in membrane cholesterol could be a causative factor, as organised F-actin structure emanates from cholesterol-enriched raft microdomains at the plasma membrane. METHODS: Skeletal muscle samples from high-fat-fed animals and insulin-sensitive and insulin-resistant human participants were evaluated.

Author(s): 
Habegger, K. M.
Penque, B. A.
Sealls, W.
Tackett, L.
Bell, L. N.
Blue, E. K.
Gallagher, P. J.
Sturek, M.
Alloosh, M. A.
Steinberg, H. O.
Considine, R. V.
Elmendorf, J. S.
Publication Title: 
Molecular Aspects of Medicine

Fish oil, enriched in bioactive n-3 polyunsaturated fatty acids (PUFA), has therapeutic value for the treatment of inflammation-associated disorders. The effects of n-3 PUFAs are pleiotropic and complex; hence, an understanding of their cellular targets and molecular mechanisms of action remains incomplete. Here we focus on recent data indicating n-3 PUFAs exert immunosuppressive effects on the function of effector and regulatory CD4(+) T cells. In addition, we also present emerging evidence that n-3 PUFAs have immunomodulatory effects on B cells.

Author(s): 
Shaikh, Saame Raza
Jolly, Christopher A.
Chapkin, Robert S.
Publication Title: 
The Journal of Nutritional Biochemistry

N-3 polyunsaturated fatty acids (PUFAs) from fish oil exert their functional effects by targeting multiple mechanisms. One mechanism to emerge in the past decade is the ability of n-3 PUFA acyl chains to perturb the molecular organization of plasma membrane sphingolipid/cholesterol-enriched lipid raft domains. These domains are nanometer-scale assemblies that coalesce to compartmentalize select proteins for optimal function. Here we review recent evidence on how n-3 PUFAs modify lipid rafts from biophysical and biochemical experiments from several different model systems.

Author(s): 
Shaikh, Saame Raza

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