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1.
Langmuir ; 40(12): 6484-6492, 2024 Mar 26.
Article in English | MEDLINE | ID: mdl-38470245

ABSTRACT

Interactions between the sigma1 receptor agonist PRE-084 and various lipid monolayers, including dipalmitoylphosphatidylcholine (DPPC), DPP-ethanolamine (DPPE), DPP-glycerol (DPPG), DPP-serine (DPPS), palmitoylsphingomyelin (PSM), and cholesterol (Ch), were investigated to elucidate the effects of PRE-084 on membrane fluidity and stability. Their interactions with sigma1 receptor agonists have potential implications for neuroprotection, antidepressant, analgesic, and cognitive enhancement effects. In this study, we observed that the presence of PRE-084 in the subphase led to increased fluidity in DPPC and DPPE monolayers, whereas decreasing fluidity was observed in DPPG, DPPS, and PSM monolayers. The interaction of PRE-084 with Ch monolayers was found to be distinct from its interaction with other lipids. Fluorescence microscopy images revealed changes in the size and shape of liquid-condensed domains in the presence of PRE-084, supporting the notion of altered membrane fluidity. Our findings provide new insights into the interaction of PRE-084 with lipid monolayers and its potential implications for biological and membrane science.


Subject(s)
1,2-Dipalmitoylphosphatidylcholine , Membrane Fluidity , Phenyl Ethers , Microscopy, Fluorescence
3.
Biochem Biophys Res Commun ; 673: 29-35, 2023 09 17.
Article in English | MEDLINE | ID: mdl-37356142

ABSTRACT

BACKGROUND: The development of effective therapies and biomarkers for pancreatic cancer is an unmet clinical need. To address this, we have developed an easy-to-use pancreatic cancer rat animal model via pancreas-targeted hydrodynamic gene delivery of human pancreatic cancer-related genes. Our study aimed to determine the molecular similarity between the pancreatic tumor in the rat model and human pancreatic cancer. METHODS: KRASG12D gene-expressing plasmid was delivered to the pancreas of wild type rats via pancreas-targeted hydrodynamic gene delivery as previously reported. Tissue samples were collected at 5 weeks after the first gene delivery. The tumors developed in the rats were assessed for the expression of oncogenic proteins that are involved in human pancreatic cancer development. RESULTS: The development of a tumor mimicking pancreatic ductal adenocarcinoma was confirmed. The expression levels of Cyclin D1, c-Jun, IL-33, and Zip4 proteins in the tumor were immunohistochemically assessed and the correlation of the proteins was confirmed. The expression pattern showed similarity to that of surgically resected human pancreatic cancer tissues. CONCLUSIONS: Our study findings showing a similar pattern of oncogenic protein expression in novel KRASG12D gene-induced rat pancreatic cancer model and human pancreatic cancer will be useful for establishing novel tumor markers and therapeutic options for pancreatic cancer.


Subject(s)
Carcinoma, Pancreatic Ductal , Pancreatic Neoplasms , Humans , Animals , Rats , Proto-Oncogene Proteins p21(ras)/metabolism , Signal Transduction , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/therapy , Pancreatic Neoplasms/metabolism , Pancreas/metabolism , Carcinoma, Pancreatic Ductal/genetics , Carcinoma, Pancreatic Ductal/therapy , Carcinoma, Pancreatic Ductal/metabolism , Pancreatic Neoplasms
4.
Biochem Biophys Rep ; 32: 101352, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36160029

ABSTRACT

Background: Hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) accounts for 10%-20% of the total HCC numbers. Its clinical features include the occurrence in the younger generation, large tumors, and poor prognosis. The contribution of hepatitis B virus X (HBx) protein in hepatocytes during activation of various oncogenic pathways has been reported. We aimed to assess the possible association between HBx and Yes-associated protein (YAP) expression in the liver tissue and the clinical features of HBV-related HCC. Methods: The relationship between HBx and YAP expression was examined in vivo using HCC tumor and peritumor tissues (n = 55). The clinical information including tumor size, marker, and the prognosis was assessed with protein expressions. The in vitro gene expression analyses were conducted using HBx- and YAP-overexpressing HCC cell lines. Results: Among 19 cases of HBV-related, 17 cases of hepatitis C virus (HCV)-related, and 19 cases of nonviral-related HCC, the HBV-related tumor showed the largest size. The HBx-stained area in the tumor and peritumor tissue showed a significant correlation with tumor size and serum α-fetoprotein level. YAP expression was higher in HBV-related tumor tissue than in the peritumor tissue and HCV-related tumor. Additionally, HBx and YAP protein expressions are correlated and both expressions in the tumor contributed to the poor prognosis. An in vitro study demonstrated that HBx and YAP overexpression in the hepatocytes activate the various oncogenic signaling pathways. Conclusions: Our study demonstrated that YAP expression in the liver of HBV-infected patients might be the key factor in HBV-related HCC development and control of tumor-related features.

5.
Sci Rep ; 12(1): 10105, 2022 06 16.
Article in English | MEDLINE | ID: mdl-35710868

ABSTRACT

Melanocortin 4 receptor gene-knockout (MC4R-KO) mice are known to develop obesity with a high-fat diet. Meanwhile, daisaikoto, one of Kampo medicines, is a drug that is expected to have therapeutic effects on obesity. Here, we report the efficacy of daisaikoto in MC4R-KO mice. Eight-week-old MC4R-KO male mice (n = 12) were divided into three groups as follows: the SD group, which is fed with a standard diet; the HFD group, fed a high-fat diet; and the DSK group, fed with a high-fat diet containing 10% of daisaikoto. After the four-week observation period, mice in each group were sacrificed and samples were collected. The body weights at 12 weeks were significantly higher in the HFD group than in the other groups, indicating that daisaikoto significantly reduced body weight gain and fat deposition of the liver. The metabolome analysis indicated that degradation of triglycerides and fatty acid oxidation in the liver were enhanced by daisaikoto administration. In MC4R-KO mice, the cytoplasm and uncoupling protein 1 expression of brown adipose tissue was decreased; however, it was reversed in the DSK group. In conclusion, daisaikoto has potentially improved fatty liver and obesity, making it a useful therapeutic agent for obesity and fatty liver.


Subject(s)
Adipose Tissue, Brown , Fatty Liver , Adipose Tissue/metabolism , Animals , Diet, High-Fat/adverse effects , Drugs, Chinese Herbal , Fatty Liver/drug therapy , Fatty Liver/genetics , Fatty Liver/metabolism , Liver/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Obesity/drug therapy , Obesity/genetics , Obesity/metabolism , Receptor, Melanocortin, Type 4
6.
Dis Model Mech ; 15(7)2022 07 01.
Article in English | MEDLINE | ID: mdl-35765850

ABSTRACT

Serotonin (5-HT) is one of the key bioamines of nonalcoholic fatty liver disease (NAFLD). Its mechanism of action in autonomic neural signal pathways remains unexplained; hence, we evaluated the involvement of 5-HT and related signaling pathways via autonomic nerves in NAFLD. Diet-induced NAFLD animal models were developed using wild-type and melanocortin 4 receptor (MC4R) knockout (MC4RKO) mice, and the effects of the autonomic neural axis on NAFLD physiology, 5-HT and its receptors (HTRs), and lipid metabolism-related genes were assessed by applying hepatic nerve blockade. Hepatic neural blockade retarded the progression of NAFLD by reducing 5-HT in the small intestine, hepatic HTR2A and hepatic lipogenic gene expression, and treatment with an HTR2A antagonist reproduced these effects. The effects were milder in MC4RKO mice, and brain 5-HT and HTR2C expression did not correlate with peripheral neural blockade. Our study demonstrates that the autonomic liver-gut neural axis is involved in the etiology of diet-induced NAFLD and that 5-HT and HTR2A are key factors, implying that the modulation of the axis and use of HTR2A antagonists are potentially novel therapeutic strategies for NAFLD treatment. This article has an associated First Person interview with the first author of the paper.


Subject(s)
Non-alcoholic Fatty Liver Disease , Animals , Diet, High-Fat , Humans , Lipid Metabolism , Liver/metabolism , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/drug therapy , Serotonin/metabolism
7.
Intern Med ; 61(21): 3233-3237, 2022 Nov 01.
Article in English | MEDLINE | ID: mdl-35431306

ABSTRACT

Regarding the prognosis of cases with advanced-stage hepatocellular carcinoma (HCC), a recent clinical study showed that the immune checkpoint inhibitors atezolizumab plus bevacizumab have superior efficacy to sorafenib. However, only a few reports have focused on their effects on extrahepatic metastases. We herein report a case of HCC in a 59-year-old man with intrahepatic lesions treated successfully by hepatic arterial chemoembolization, radiotherapy, and sorafenib; the extrahepatic lesion in the adrenal gland was treated by atezolizumab plus bevacizumab. The patient showed a tumor-free condition for one year. We have summarized the clinical course and reviewed the literature to underscore the efficacy of atezolizumab plus bevacizumab for treating extrahepatic lesions of HCC.


Subject(s)
Adrenal Gland Neoplasms , Carcinoma, Hepatocellular , Liver Neoplasms , Male , Humans , Middle Aged , Carcinoma, Hepatocellular/pathology , Bevacizumab/therapeutic use , Sorafenib/therapeutic use , Liver Neoplasms/pathology , Adrenal Gland Neoplasms/diagnostic imaging , Adrenal Gland Neoplasms/drug therapy , Adrenal Gland Neoplasms/secondary , Adrenal Glands/pathology
8.
Mol Ther Nucleic Acids ; 28: 342-352, 2022 Jun 14.
Article in English | MEDLINE | ID: mdl-35474735

ABSTRACT

This research developed an easy-to-use, reproducible pancreatic cancer animal model utilizing pancreas-targeted hydrodynamic gene delivery to deliver human pancreatic cancer-related genes to the pancreas of wild-type rats. KRAS G12D -induced pancreatic intraepithelial neoplasia lesions showed malignant transformation in the main pancreatic duct at 4 weeks and developed acinar-to-ductal metaplasia, which led to pancreatic ductal adenocarcinoma within 5 weeks, and the gene combination of KRAS G12D and YAP enhanced these effects. The repeat hydrodynamic gene delivery of KRAS G12D  + YAP combination at 4 weeks showed acinar-to-ductal metaplasia in all rats and pancreatic ductal adenocarcinoma in 80% of rats 1 week later. Metastatic tumors in the liver, lymph nodes, and subcutaneous lesions and nervous invasion were confirmed. KRAS G12D and YAP combined transfer contributes to the E- to N-cadherin switch in pancreatic ductal adenocarcinoma cells and to tumor metastases. This pancreatic cancer model will speed up pancreatic cancer research for novel treatments and biomarkers for early diagnosis.

9.
Biochem Biophys Res Commun ; 596: 76-82, 2022 03 12.
Article in English | MEDLINE | ID: mdl-35121372

ABSTRACT

OBJECTIVE: Nonalcoholic steatohepatitis (NASH) is a disease entity with an increasing incidence, with involvement of several metabolic pathways. Various organs, including the liver, kidneys, and the vasculature, are damaged in NASH, indicating the urgent need to develop a standard therapy. Therefore, this study was conducted to investigate the effects of drugs targeting various metabolic pathways and their combinations on a high-fat diet (HFD)-induced NASH medaka model. METHODS: To investigate the effects of drugs on vascular structures, the NASH animal model was developed using the fli::GFP transgenic medaka fed with HFD at 20 mg/fish daily. The physiological changes, histological changes in the liver, vascular structures in the fin, and serum biochemical markers were evaluated in a time-dependent manner after treatment with selective peroxisome proliferator-activated receptor α modulator (pemafibrate), statin (pitavastatin), sodium-glucose cotransporter 2 inhibitor (tofogliflozin), and their combinations. Furthermore, to determine the mechanisms underlying the effects, whole transcriptome sequencing was conducted using medaka liver samples. RESULTS: Histological analyses revealed significant suppression of fat accumulation and fibrotic changes in the liver after treatment with drugs and their combinations. The expression levels of steatosis- and fibrosis-related genes were modified by the treatments. Moreover, the HFD-induced vascular damages in the fin exhibited milder changes after treatment with the drugs. CONCLUSION: The effects of treating various metabolic pathways on the medaka body, liver, and vascular structures of the NASH medaka model were evidenced. Moreover, to our knowledge, this study is the first to report whole genome sequence and gene expression evaluation of medaka livers, which could be helpful in clarifying the molecular mechanisms of drugs.


Subject(s)
Animal Fins/drug effects , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Liver/drug effects , Non-alcoholic Fatty Liver Disease/genetics , Oryzias/genetics , PPAR alpha/genetics , Sodium-Glucose Transporter 2 Inhibitors/pharmacology , Animal Fins/blood supply , Animals , Animals, Genetically Modified , Benzhydryl Compounds/pharmacology , Benzoxazoles/pharmacology , Butyrates/pharmacology , Diet, High-Fat/adverse effects , Disease Models, Animal , Gene Ontology , Glucosides/pharmacology , Liver/metabolism , Liver/pathology , Non-alcoholic Fatty Liver Disease/etiology , Non-alcoholic Fatty Liver Disease/metabolism , Oryzias/metabolism , PPAR alpha/metabolism , Quinolines/pharmacology , Reverse Transcriptase Polymerase Chain Reaction , Transcriptome/drug effects , Transcriptome/genetics , Exome Sequencing/methods
10.
J Clin Med ; 11(3)2022 Feb 06.
Article in English | MEDLINE | ID: mdl-35160302

ABSTRACT

Cyclin D1 binding protein 1 (CCNDBP1) is considered a tumor suppressor, and when expressed in tumor cells, CCNDBP1 can contribute to the viability of cancer cells by rescuing these cells from chemotherapy-induced DNA damage. Therefore, this study focused on investigating the function of CCNDBP1, which is directly related to the survival of cancer cells by escaping DNA damage and chemoresistance. Hepatocellular carcinoma (HCC) cells and tissues obtained from Ccndbp1 knockout mice were used for the in vitro and in vivo examination of the molecular mechanisms of CCNDBP1 associated with the recovery of cells from DNA damage. Subsequently, gene and protein expression changes associated with the upregulation, downregulation, and irradiation of CCNDBP1 were assessed. The overexpression of CCNDBP1 in HCC cells stimulated cell growth and showed resistance to X-ray-induced DNA damage. Gene expression analysis of CCNDBP1-overexpressed cells and Ccndbp1 knockout mice revealed that Ccndbp1 activated the Atm-Chk2 pathway through the inhibition of Ezh2 expression, accounting for resistance to DNA damage. Our study demonstrated that by inhibiting EZH2, CCNDBP1 contributed to the activation of the ATM-CHK2 pathway to alleviate DNA damage, leading to chemoresistance.

11.
Colloids Surf B Biointerfaces ; 211: 112333, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35038654

ABSTRACT

The surface chemistry of the inverse electron-demand Diels-Alder (IEDDA) reaction at the air-water interface is elucidated. Tetrazine (C18-Tz) and norbornene derivatives (C16-NCA) were used as the reactants. Langmuir monolayers of C18-Tz, C16-NCA, and their binary mixtures were prepared on aqueous substrates. The surface properties were analyzed using the surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms, as well as fluorescence microscopy to monitor the progress of the reaction. First, to provide comparison data to evaluate the reaction on the surface, the two components were mixed in stock solutions of organic solvents for the IEDDA reaction. The Langmuir monolayer spread from the reaction solution was characterized as a function of the reaction time. In the subsequent experiments, the Langmuir monolayers were deposited onto the surface of the substrate solutions by spreading from separate stock solutions of C18-Tz and C16-NCA. The variation of the surface behavior of the monolayers with the molecular area, surface composition of the two components, compression speed of the monolayers, and the temperature was studied. We discuss the effects of the air phase in the reaction field on the reaction efficiency by comparing the results obtained from the two methods.


Subject(s)
Electrons , Heterocyclic Compounds , Cycloaddition Reaction , Norbornanes/chemistry , Water
12.
Biophys Rev (Melville) ; 3(2): 021303, 2022 Jun.
Article in English | MEDLINE | ID: mdl-38505415

ABSTRACT

Tetrazine (Tz) is an emerging bioorthogonal ligand that is expected to have applications (e.g., bioimaging) in chemistry and chemical biology. In this review, we highlight the interactions of reduced tetrazine (rTz) derivatives insoluble in aqueous media with biological membrane constituents or their related lipids, such as dipalmitoyl-phosphatidylcholine, dipalmitoyl-phosphatidylethanolamine, dipalmitoyl-phosphatidylglycerol, palmitoyl-sphingomyelin, and cholesterol in the Langmuir monolayer state at the air-water interface. The two-component interaction was thermodynamically elucidated by measuring the surface pressure (π) and molecular area (A) isotherms. The monolayer miscibility between the two components was analyzed using the excess Gibbs energy of mixing and two-dimensional phase diagram. The phase behavior of the binary monolayers was studied using the Brewster angle, fluorescence, and atomic force microscopy. This study discusses the affinities of the rTz moieties for the hydrophilic groups of the lipids used.

13.
Dis Model Mech ; 14(3)2021 03 28.
Article in English | MEDLINE | ID: mdl-33787507

ABSTRACT

The etiology of non-alcoholic fatty liver disease (NAFLD) consists of various factors, including neural signal pathways. However, the molecular mechanisms of the autonomic neural signals influencing NAFLD progression have not been elucidated. Therefore, we examined the involvement of the gut-liver neural axis in NAFLD development and tested the therapeutic effect of modulation of this axis in this study. To test the contribution of the gut-liver neural axis, we examined NAFLD progression with respect to body weight, hepatic steatosis, fibrosis, intestinal tight junction, microbiota and short-chain fatty acids in NAFLD models of choline-deficient defined L-amino-acid and high-fat diet-fed mice with or without blockades of autonomic nerves from the liver. Blockade of the neural signal from the liver to the gut in these NAFLD mice models ameliorated the progression of liver weight, hepatic steatosis and fibrosis by modulating serotonin expression in the small intestine. It was related to the severity of the liver pathology, the tight junction protein expression, microbiota diversity and short-chain fatty acids. These effects were reproduced by administrating serotonin antagonist, which ameliorated the NAFLD progression in the NAFLD mice models. Our study demonstrated that the gut-liver neural axis is involved in the etiologies of NAFLD progression and that serotonin expression through this signaling network is the key factor of this axis. Therefore, modulation of the gut-liver neural axis and serotonin antagonist ameliorates fatty and fibrotic changes in non-alcoholic fatty liver, and can be a potential therapeutic target of NAFLD.This article has an associated First Person interview with the first author of the paper.


Subject(s)
Autonomic Nervous System/metabolism , Gastrointestinal Tract/metabolism , Liver Cirrhosis/metabolism , Liver/metabolism , Non-alcoholic Fatty Liver Disease/metabolism , Serotonin/metabolism , Animals , Body Weight , Diet, High-Fat , Disease Models, Animal , Gastrointestinal Microbiome , Gastrointestinal Tract/pathology , Liver/pathology , Liver Cirrhosis/pathology , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/pathology , Organ Size , Signal Transduction , Tight Junctions/metabolism
14.
Intern Med ; 60(11): 1709-1715, 2021 Jun 01.
Article in English | MEDLINE | ID: mdl-33390501

ABSTRACT

Basic and clinical research have shown that the expression of molecules involved in the hepatocellular carcinoma (HCC) cell signaling pathway is related to the sensitivity to molecular-targeted agents. We herein report a case of HCC that was effectively treated with lenvatinib after a poor response to sorafenib. The tumor showed a high expression of fibroblast growth factor receptor 4, which is reportedly related to the sensitivity to lenvatinib in vitro. The information obtained from this case and from our literature review highlights the importance of assessing the expression of the molecules involved in tumors for effective precision medicine.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Carcinoma, Hepatocellular/drug therapy , Fibroblast Growth Factors , Humans , Liver Neoplasms/drug therapy , Phenylurea Compounds , Quinolines , Receptor, Fibroblast Growth Factor, Type 4
15.
Cancers (Basel) ; 12(10)2020 Oct 13.
Article in English | MEDLINE | ID: mdl-33066141

ABSTRACT

This study investigated the efficacy and safety of radiotherapy as part of multidisciplinary therapy for advanced hepatocellular carcinoma (HCC). Clinical data of 49 HCC patients treated with radiotherapy were assessed retrospectively. The efficacy of radiotherapy was assessed by progression-free survival, disease control rate, and overall survival. Safety was assessed by symptoms and hematological assay, and changes in hepatic reserve function were determined by Child-Pugh score and albumin-bilirubin (ALBI) score. Forty patients underwent curative radiotherapy, and nine patients with portal vein tumor thrombus (PVTT) underwent palliative radiotherapy as part of multidisciplinary therapy. Local disease control for curative therapy was 80.0% and stereotactic body radiotherapy was 86.7% which was greater than that of conventional radiotherapy (60.0%). Patients with PVTT had a median observation period of 651 days and 75% three-year survival when treated with multitherapy, including radiotherapy for palliative intent, transcatheter arterial chemoembolization, and administration of molecular targeted agents. No adverse events higher than grade 3 and no changes in the Child-Pugh score and ALBI score were seen. Radiotherapy is safe and effective for HCC treatment and can be a part of multidisciplinary therapy.

16.
Chemphyschem ; 21(17): 1966-1970, 2020 09 02.
Article in English | MEDLINE | ID: mdl-32710449

ABSTRACT

We found that monolayers of dipalmitoylphosphatidylcholine (DPPC) and semi-fluorinated tetrablock di(F10H16) self-assemble to form a new type of large, complex flower-like patterns on the surface of water and on solid substrates. The hierarchical organization of these unusual self-assemblies was investigated using compression and surface potential isotherms, in situ fluorescence and Brewster angle microscopies, and atomic force microscopy after transfer.

18.
JGH Open ; 4(2): 301-302, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32280786

ABSTRACT

Intrahepatic cholangiocarcinoma is the second leading primary hepatic tumors, accounting for 5% of all hepatic tumors. The curability depends on the operability; however, the difficulty of early diagnosis and late clinical presentation account for the poor prognosis. Therefore, development of a novel therapeutic option and a method to determine the viability of the primary tumor, which hinder the assessment of the impact of other therapies, including chemotherapy and radiotherapy are needed. Although FDG-PET has been used to detect distant metastases of ICC, which are present in 20% of patients at the initial diagnosis, little is known about the efficacy of FDG-PET of the primary lesion of ICC. Here, we present the case of a 31-year-old male diagnosed with unresectable ICC and successfully treated with carbon-ion radiation, and present the usefulness of fluorodeoxyglucose-positron emission tomography in the determination of the viability of the tumor.

19.
World J Clin Cases ; 7(21): 3553-3561, 2019 Nov 06.
Article in English | MEDLINE | ID: mdl-31750337

ABSTRACT

BACKGROUND: Immunosuppression is effective in treating a number of diseases, but adverse effects such as bone marrow suppression, infection, and oncogenesis are of concern. Methotrexate is a key immunosuppressant used to treat rheumatoid arthritis. Although it is effective for many patients, various side effects have been reported, one of the most serious being methotrexate-related lymphoproliferative disorder. While this may occur in various organs, liver involvement is rare. Information on these liver lesions, including clinical characteristics, course, and imaging studies, has not been summarized to date. CASE SUMMARY: We present a case of 70-year-old woman presented with a 2-wk history of fever and abdominal pain. She had had rheumatoid arthritis for 5 years and was being treated with medication including methotrexate. Contrast-enhanced computed tomography revealed multiple low density tumors in the liver and the histological analyses showed significant proliferation of lymphocytes in masses that were positive on immunohistochemical staining for CD3, CD4, CD8, and CD79a but negative for CD20 and CD56. Staining for Epstein-Barr virus-encoded RNA was negative. And based on these findings, the liver tumors were diagnosed as Methotrexate-related lymphoproliferative disorders. A time-dependent disappearance of the liver tumors after stopping methotrexate supported the diagnoses. CONCLUSION: The information obtained from our case and a review of 9 additional cases reported thus far assist physicians who may face the challenge of diagnosing and managing this disorder.

20.
Colloids Surf B Biointerfaces ; 181: 1035-1040, 2019 Sep 01.
Article in English | MEDLINE | ID: mdl-31382331

ABSTRACT

Lipid rafts consisting mainly of sphingomyelin and cholesterol (Ch) on biomembrane surfaces are deeply related to cellular processes such as protein trafficking and signal transduction. During the processes, the raft microdomains affect the fluidty of biological membranes, which is controlled to large extents by Ch. In this paper, we have investigated the interaction between Ch and a semiflurinated alcohol (F6H9OH) from the aspect of a fluidty control using surface chemistry. The two-component Langmuir monolayer at the air-water interface was characterized by the surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms. The compressibility modulus and excess Gibbs free energy of mixing were calculated from the π-A isotherms. And also the two-dimensional phase diagram was constructed on the basis of phase transition pressures and monolayer collapse pressures. Furthermore, the phase behavior of binary monolayers was visualized with fluorescence microscopy (in situ) and atomic force microscopy (ex situ). The result here indicates a possibility of fluidity control of Ch-related membranes by arranging the fluorination degree of the constituent lipids.


Subject(s)
Air , Cholesterol/chemistry , Halogenation , Surface-Active Agents/chemistry , Water/chemistry , Particle Size , Surface Properties
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