Distribution Of Lipid Molecules Research Articles

Characteristics of lipid metabolism after treatment of colon cancer mice with American ginseng vesicles.

Lipid molecules are present in tumours and play an important role in the anti-inflammatory response as well as in antiviral protection. Changes in the type and location of lipids in the intestine following exposure to environmental stressors play an important role in several disorders, including ulcerative colitis (UC), inflammatory bowel disease (IBD), and colorectal cancer. The aim of this work is to provide a new theoretical basis for tumour initiation and development by accurately measuring the spatial distribution of lipids and metabolites in intestinal tissue. Spatial metabolomics allows the detection of samples with minimal sample volume by label-free imaging of complex samples in their original state. The distribution of lipid molecules in tumours has not been reported, although the distribution of lipid molecules in intestinal tissue has been reported in the literature. The range of lipid profiles in colon cancer mouse tumour tissue was compiled using a spatial metabolomics: lipid extraction method. The changes in lipid distribution in two regions after oral administration of American Ginseng (Panax quinquefolius L.) vesicles were also compared. Tumour tissue samples were extracted with 80% methanol-20% formic acid in water. The resulting spatial metabolic profile allowed the identification of seven lipid classes in mouse tumours. The distribution of fibre tissue cells was 23.2% higher than tumour tissue cells, with the exception of the fatty acid (FA) species.

Effect of Functional Groups in Lipid Molecules on the Stability of Nanostructured Lipid Carriers: Experimental and Computational Investigations.

Lipid nanoparticles have been used as drug carriers for decades. Many lipid types have been screened for both solid lipid nanoparticles and nanostructured lipid carriers (NLCs). Specifically, for NLCs that are composed of lipids in the solid form mixed with lipids in the liquid form, compatibility of lipid combination and phase behavior play a significant role in the NLC quality. In this study, stearic acid (STA) and cetyl palmitate (CTP) were used as solid lipids, and oleic acid (OLA), isopropyl palmitate (IPP), and caprylic/capric triglycerides were used as liquid lipids. NLCs were prepared at solid:liquid ratios of 50:50, 70:30, and 90:10, respectively. The characteristics and stability of the prepared NLCs were investigated. Laboratory results showed that the solid lipid had a greater influence on the particle size than the liquid lipid. Meanwhile, cetyl palmitate, an ester compound, provides higher NLC stability compared to stearic acid, a carboxylic acid compound. A MARTINI-based coarse-grained molecular dynamics simulation was used to simulate the lipid droplet in water. The distribution of lipid molecules in the droplet was characterized by the polar group density distribution. Different spatial arrangements of the lipid headgroup and lipid molecules, when CTP or STA was used as solid lipids, might contribute to the different stabilities of prepared NLCs. The understanding of mixed lipid systems via simulations will be a significant tool for screening the type of lipids for drug carriers and other pharmaceutical applications.

Formation of GM1 Ganglioside Clusters on the Lipid Membrane Containing Sphingomyeline and Cholesterol

GM1 gangliosides form a microdomain with sphingomyeline (SM) and cholesterol (Chol) and are deeply involved in the aggregation of amyloid beta (Aβ) peptides on neural membranes. We performed molecular dynamics simulations on two kinds of lipid bilayers containing GM1 ganglioside: GM1/SM/Chol and GM1/POPC. Both 10 and 100 ns simulations and another set of 10 ns simulations with different initial lipid arrangement essentially showed the same computational results. GM1 molecules in the GM1/SM/Chol membrane were condensed, whereas those in GM1/POPC membrane scattered. That is, the formation of GM1 cluster was observed only on the GM1/SM/Chol mixed membrane. There appeared numerous hydrogen bonds among glycan portions of the GM1 clusters due to the condensation. A comparison in distribution of lipid molecules between the two kinds of membranes suggested that cholesterol had important roles to prevent the membrane from interdigitation and to stabilize other lipids for interacting with each other. This property of cholesterol promotes the formation of GM1 clusters.

Changes in cholesterol levels in the plasma membrane modulate cell signaling and regulate cell adhesion and migration on fibronectin

The number and distribution of lipid molecules, including cholesterol in particular, in the plasma membrane, may play a key role in regulating several physiological processes in cells. We investigated the role of membrane cholesterol in regulating cell shape, adhesion and motility. The acute depletion of cholesterol from the plasma membrane of cells that were well spread and motile on fibronectin caused the rounding of these cells and decreased their adhesion to and motility on fibronectin. These modifications were less pronounced in cells plated on laminin, vitronectin or plastic, indicating that cholesterol-mediated changes in adhesion and motility are more specific for adhesion mediated by fibronectin-specific integrins, such as alpha5beta1. These changes were accompanied by remodeling of the actin cytoskeleton, the spatial reorganization of paxillin in the membrane, and changes to the dynamics of alpha5 integrin and paxillin-rich focal adhesions. Levels of tyrosine phosphorylation at position 576/577 of FAK and Erk1/Erk2 MAP-kinase activity levels were both lower in cholesterol-depleted than in control cells. These levels normalized only on fibronectin when cholesterol was reincorporated into the cell membrane. Thus, membrane cholesterol content has a specific effect on certain signaling pathways specifically involved in regulating cell motility on fibronectin and organization of the actin cytoskeleton.

Phospholipid Distribution Around the Plasma Membrane Calcium Pump: A Hydrophobic Photolabeling Study

The functions of membrane proteins are highly dependent on their phospholipid environment. In this article, we have used a hydrophobic photolabeling method to study the noncovalent interactions between plasma membrane calcium pump (PMCA) and surrounding phospholipids. With this approach, we determined (1) the number of lipid molecules in close contact with the transmembrane surface, i.e., the lipid-protein stoichiometry, and (2) the distribution of lipid molecules among different regions of the protein. PMCA was photolabeled in mixed micelles containing detergent, the phosphatidylcholine photoactivatable analog 1-palmitoyl-2-[9-[2'-[125I]iodo-4'- (trifluoromethyldiazirinyl)-benzyloxycarbonyl]-nonaoyl]-sn-glycero-3-phosphocholine, and different amounts of dimyristoyl phosphatidylcholine (PC). The stoichiometry was estimated after the extent of the labeling reaction had been independently assessed. We determined a maximum number of 17 +/- 1 molecules of PC in close contact with the transmembrane surface per PMCA molecule. In addition, a semiquantitative description of the phospholipid environment around different regions of PMCA was carried out after limited proteolysis of the photolabeled protein. The distribution of labels among the N-terminal (1-322), the central (323-660), and the C-terminal (661-1,205) regions was 26, 36, and 38%, respectively.

Scanning Electrochemical Microscopy Studies of Electron Transfer through Monolayers Containing Conjugated Species at the Liquid−Liquid Interface

The rates of electron transfer (ET) between two redox species through a monolayer of saturated dipalmytoyl phosphocholine and polyconjugated 2(3-(diphenylhexatrienyl)propanoyl)-1-hexadecanoyl-sn-glycero-3-phosphocholine phospholipids adsorbed at the interface of two immiscible electrolyte solutions (ITIES) were measured by scanning electrochemical microscopy. Comparison of the ET rates shows that addition of phospholipids with conjugated hydrocarbon chains increases the ET rate by at least a factor of 2 compared to films with only saturated hydrocarbon chains. This difference was sufficiently high to obtain information about distribution of lipid molecules in monolayers formed by mixing two lipids. Lateral scanning of an ultramicroelectrode tip across the lipid monolayer comprised of two different phospholipids showed that each lipid forms microsize domains. The rate of ET across a monolayer of lipid adsorbed at the ITIES was also probed as a function of temperature. A sharp decrease in ET rate with tempe...