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1.
J Cell Biol ; 223(6)2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38551495

ABSTRACT

Lipid droplets (LDs) are composed of a core of neutral lipids wrapped by a phospholipid (PL) monolayer containing several hundred proteins that vary between different cells or organisms. How LD proteins target to LDs is still largely unknown. Here, we show that RNAi knockdown or gene mutation of let-767, encoding a member of hydroxysteroid dehydrogenase (HSD), displaced the LD localization of three well-known LD proteins: DHS-3 (dehydrogenase/reductase), PLIN-1 (perilipin), and DGAT-2 (diacylglycerol O-acyltransferase 2), and also prevented LD growth in Caenorhabditis elegans. LET-767 interacts with ARF-1 (ADP-ribosylation factor 1) to prevent ARF-1 LD translocation for appropriate LD protein targeting and lipid homeostasis. Deficiency of LET-767 leads to the release of ARF-1, which further recruits and promotes translocation of ATGL-1 (adipose triglyceride lipase) to LDs for lipolysis. The displacement of LD proteins caused by LET-767 deficiency could be reversed by inhibition of either ARF-1 or ATGL-1. Our work uncovers a unique LET-767 for determining LD protein targeting and maintaining lipid homeostasis.


Subject(s)
Alcohol Oxidoreductases , Caenorhabditis elegans Proteins , Lipid Droplets , Homeostasis , Lipase/genetics , Lipid Droplet Associated Proteins/metabolism , Lipid Droplets/metabolism , Lipid Metabolism/genetics , Lipids , Lipolysis/physiology , Proteins/metabolism , Caenorhabditis elegans , Animals , Alcohol Oxidoreductases/metabolism , Caenorhabditis elegans Proteins/metabolism
2.
Front Pharmacol ; 13: 1061842, 2022.
Article in English | MEDLINE | ID: mdl-36569303

ABSTRACT

As the body's critical metabolic organ, the liver plays an essential role in maintaining proper body homeostasis. However, as people's living standards have improved and the number of unhealthy lifestyles has increased, the liver has become overburdened. These have made liver disease one of the leading causes of death worldwide. Under the influence of adverse factors, liver disease progresses from simple steatosis to hepatitis, to liver fibrosis, and finally to cirrhosis and cancer, followed by increased mortality. Until now, there has been a lack of accepted effective treatments for liver disease. Based on current research, antisense oligonucleotide (ASO), as an alternative intervention for liver diseases, is expected to be an effective treatment due to its high efficiency, low toxicity, low dosage, strong specificity, and additional positive characteristics. In this review, we will first introduce the design, modification, delivery, and the mechanisms of ASO, and then summarize the application of ASO in liver disease treatment, including in non-alcoholic fatty liver disease (NAFLD), hepatitis, liver fibrosis, and liver cancer. Finally, we discuss challenges and perspectives on the transfer of ASO drugs into clinical use. This review provides a current and comprehensive understanding of the integrative and systematic functions of ASO for its use in liver disease.

3.
Comput Intell Neurosci ; 2022: 6951532, 2022.
Article in English | MEDLINE | ID: mdl-35958754

ABSTRACT

Computer vision is an interesting branch of artificial intelligence which is dedicated to how electronic devices can achieve the level of capabilities to perceive things just like ordinary human beings do. In order to solve the poor effect of video for the detection of target in football matches and the low accuracy of target tracking, this paper aims to make a deep exploration of the methods of video for the detection of target and tracking in football matches. The video moving for the detection of target method based on background model is used to extract the image in the background of the matching video which improves the light flow field. Secondly, the video differential image is acquired according to the difference of colors, the ghost target of the image in the video background model is scientifically determined, the ghost degree of the pixel points of the image is scientifically determined, and the flicker matrix of the target image is constructed. The number of pixels of the moving target is derived. A meanshift-based video target tracking algorithm is used in conjunction for the detection of target result to determine whether to track the target image until the overall video target tracking task is completed, move the central position of the target frame and background frame to the target position, select the best one to adapt to the target change, and determine whether to track the target image until the overall video target tracking task is completed. The simulation results suggest that the approach described in this study is capable of detecting and tracking moving objects, as well as improving target recognition and tracking accuracy.


Subject(s)
Artificial Intelligence , Football , Algorithms , Computer Simulation , Humans , Video Recording/methods
4.
J Biol Chem ; 298(8): 102179, 2022 08.
Article in English | MEDLINE | ID: mdl-35752365

ABSTRACT

Lipid droplets (LDs) are intracellular organelles that dynamically regulate lipids and energy homeostasis in the cell. LDs can grow through either local lipid synthesis or LD fusion. However, how lipids involving in LD fusion for LD growth is largely unknown. Here, we show that genetic mutation of acox-3 (acyl-CoA oxidase), maoc-1 (enoyl-CoA hydratase), dhs-28 (3-hydroxylacyl-CoA dehydrogenase), and daf-22 (3-ketoacyl-CoA thiolase), all involved in the peroxisomal ß-oxidation pathway in Caenorhabditis elegans, led to rapid fusion of adjacent LDs to form giant LDs (gLDs). Mechanistically, we show that dysfunction of peroxisomal ß-oxidation results in the accumulation of long-chain fatty acid-CoA and phosphocholine, which may activate the sterol-binding protein 1/sterol regulatory element-binding protein to promote gLD formation. Furthermore, we found that inactivation of either FAT-2 (delta-12 desaturase) or FAT-3 and FAT-1 (delta-15 desaturase and delta-6 desaturase, respectively) to block the biosynthesis of polyunsaturated fatty acids (PUFAs) with three or more double bonds (n≥3-PUFAs) fully repressed the formation of gLDs; in contrast, dietary supplementation of n≥3-PUFAs or phosphocholine bearing these PUFAs led to recovery of the formation of gLDs in peroxisomal ß-oxidation-defective worms lacking PUFA biosynthesis. Thus, we conclude that n≥3-PUFAs, distinct from other well-known lipids and proteins, promote rapid LD fusion leading to LD growth.


Subject(s)
Caenorhabditis elegans , Fatty Acids, Omega-3 , Animals , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Coenzyme A/metabolism , Fatty Acid Desaturases/genetics , Fatty Acid Desaturases/metabolism , Fatty Acids/metabolism , Fatty Acids, Omega-3/metabolism , Fatty Acids, Unsaturated/metabolism , Lipid Droplets/metabolism , Phosphorylcholine/metabolism , Sterols/metabolism
5.
J Genet Genomics ; 49(4): 338-349, 2022 04.
Article in English | MEDLINE | ID: mdl-35240304

ABSTRACT

Liver fibrosis is a key transformation stage and also a reversible pathological process in various types of chronic liver diseases. However, the pathogenesis of liver fibrosis still remains elusive. Here, we report that the calcium binding protein A11 (S100A11) is consistently upregulated in the integrated data from GSE liver fibrosis and tree shrew liver proteomics. S100A11 is also experimentally activated in liver fibrosis in mouse, rat, tree shrew, and human with liver fibrosis. While overexpression of S100A11 in vivo and in vitro exacerbates liver fibrosis, the inhibition of S100A11 improves liver fibrosis. Mechanistically, S100A11 activates hepatic stellate cells (HSCs) and the fibrogenesis process via the regulation of the deacetylation of Smad3 in the TGF-ß signaling pathway. S100A11 physically interacts with SIRT6, a deacetylase of Smad2/3, which may competitively inhibit the interaction between SIRT6 and Smad2/3. The subsequent release and activation of Smad2/3 promote the activation of HSCs and fibrogenesis. Additionally, a significant elevation of S100A11 in serum is observed in clinical patients. Our study uncovers S100A11 as a novel profibrogenic factor in liver fibrosis, which may represent both a potential biomarker and a promising therapy target for treating liver fibrosis and fibrosis-related liver diseases.


Subject(s)
Signal Transduction , Sirtuins , Animals , Humans , Liver/metabolism , Liver Cirrhosis/genetics , Liver Cirrhosis/metabolism , Liver Cirrhosis/pathology , Mice , Rats , Signal Transduction/physiology , Sirtuins/metabolism , Transforming Growth Factor beta/metabolism
6.
Cell Rep ; 38(2): 110206, 2022 01 11.
Article in English | MEDLINE | ID: mdl-35021096

ABSTRACT

Mitochondria are known as the powerhouse of the cell. Dysfunction of mitochondria homeostasis induces the mitochondrial unfolded protein response (UPRmt), altering cellular metabolism. How cells sense the UPRmt to rewire metabolism is largely unknown. Here, we show that inactivation of either the citric/tricarboxylic acid (TCA) cycle enzymes aco-2 or idha-1, which encode aconitase and isocitrate dehydrogenase respectively, leads to citrate accumulation. In Caenorhabditis elegans, both in vitro and in vivo, citrate accumulation consequently triggers the UPRmt and also promotes lipid accumulation. The transcription factor DVE-1 binds to the promoter of the nuclear hormone receptor nhr-80 to transactivate its expression. NHR-80 then upregulates lipogenesis and lipid accumulation, shifting excess citrate for use in lipogenesis and for storage as triacylglycerol in lipid droplets. Inactivation of DVE-1 or NHR-80 fully abolishes the citrate-induced lipid accumulation. Therefore, our work uncovers a DVE-1-NHR-80-lipogenesis axis linking the transmission of the mitochondrial stress signal to lipid metabolism.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Citric Acid/metabolism , Receptors, Cytoplasmic and Nuclear/metabolism , Unfolded Protein Response/physiology , Animals , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/physiology , Gene Expression/genetics , Gene Expression Regulation/genetics , Homeostasis , Lipid Metabolism/physiology , Lipids/physiology , Mitochondria/metabolism , Receptors, Cytoplasmic and Nuclear/physiology , Signal Transduction , Transcription Factors/metabolism
7.
J Cell Biol ; 220(11)2021 11 01.
Article in English | MEDLINE | ID: mdl-34623380

ABSTRACT

In eukaryote cells, lipid droplets (LDs) are key intracellular organelles that dynamically regulate cellular energy homeostasis. LDs originate from the ER and continuously contact the ER during their growth. How the ER affects LD growth is largely unknown. Here, we show that RNAi knockdown of acs-1, encoding an acyl-CoA synthetase required for the biosynthesis of monomethyl branched-chain fatty acids C15iso and C17iso, remarkably prevented LD growth in Caenorhabditis elegans. Dietary C17iso, or complex lipids with C17iso including phosphatidylcholine, phosphatidylethanolamine, and triacylglycerol, could fully restore the LD growth in the acs-1RNAi worms. Mechanistically, C17iso may incorporate into phospholipids to ensure the membrane integrity of the ER so as to maintain the function of ER-resident enzymes such as SCD/stearoyl-CoA desaturase and DGAT2/diacylglycerol acyltransferase for appropriate lipid synthesis and LD growth. Collectively, our work uncovers a unique fatty acid, C17iso, as the side chain of phospholipids for determining the ER homeostasis for LD growth in an intact organism, C. elegans.


Subject(s)
Endoplasmic Reticulum/metabolism , Fatty Acids/metabolism , Lipid Droplets/metabolism , Animals , Caenorhabditis elegans/metabolism , Homeostasis/physiology , Lipid Metabolism/physiology , Membranes/metabolism , Phospholipids/metabolism , RNA Interference/physiology
8.
Front Pharmacol ; 12: 696603, 2021.
Article in English | MEDLINE | ID: mdl-34234682

ABSTRACT

With the improvement of living conditions and the popularity of unhealthy eating and living habits, obesity is becoming a global epidemic. Obesity is now recognized as a disease that not only increases the risk of metabolic diseases such as type 2 diabetes (T2D), non-alcoholic fatty liver disease (NAFLD), cardiovascular disease (CVD), and cancer but also negatively affects longevity and the quality of life. The traditional Chinese medicines (TCMs) are highly enriched in bioactive compounds and have been used for the treatment of obesity and obesity-related metabolic diseases over a long period of time. In this review, we selected the most commonly used anti-obesity or anti-hyperlipidemia TCMs and, where known, their major bioactive compounds. We then summarized their multi-target molecular mechanisms, specifically focusing on lipid metabolism, including the modulation of lipid absorption, reduction of lipid synthesis, and increase of lipid decomposition and lipid transportation, as well as the regulation of appetite. This review produces a current and comprehensive understanding of integrative and systematic mechanisms for the use of TCMs for anti-obesity. We also advocate taking advantage of TCMs as another therapy for interventions on obesity-related diseases, as well as stressing the fact that more is needed to be done, scientifically, to determine the active compounds and modes of action of the TCMs.

9.
Cell Mol Gastroenterol Hepatol ; 11(3): 697-724, 2021.
Article in English | MEDLINE | ID: mdl-33075563

ABSTRACT

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) is becoming a severe liver disorder worldwide. Autophagy plays a critical role in liver steatosis. However, the role of autophagy in NAFLD remains exclusive and under debate. In this study, we investigated the role of S100 calcium binding protein A11 (S100A11) in the pathogenesis of hepatic steatosis. METHODS: We performed liver proteomics in a well-established tree shrew model of NAFLD. The expression of S100A11 in different models of NAFLD was detected by Western blot and/or quantitative polymerase chain reaction. Liver S100A11 overexpression mice were generated by injecting a recombinant adenovirus gene transfer vector through the tail vein and then induced by a high-fat and high-cholesterol diet. Cell lines with S100a11 stable overexpression were established with a recombinant lentiviral vector. The lipid content was measured with either Bodipy staining, Oil Red O staining, gas chromatography, or a triglyceride kit. The autophagy and lipogenesis were detected in vitro and in vivo by Western blot and quantitative polymerase chain reaction. The functions of Sirtuin 1, histone deacetylase 6 (HDAC6), and FOXO1 were inhibited by specific inhibitors. The interactions between related proteins were analyzed by a co-immunoprecipitation assay and immunofluorescence analysis. RESULTS: The expression of S100A11 was up-regulated significantly in a time-dependent manner in the tree shrew model of NAFLD. S100A11 expression was induced consistently in oleic acid-treated liver cells as well as the livers of mice fed a high-fat diet and NAFLD patients. Both in vitro and in vivo overexpression of S100A11 could induce hepatic lipid accumulation. Mechanistically, overexpression of S100A11 activated an autophagy and lipogenesis process through up-regulation and acetylation of the transcriptional factor FOXO1, consequently promoting lipogenesis and lipid accumulation in vitro and in vivo. Inhibition of HDAC6, a deacetylase of FOXO1, showed similar phenotypes to S100A11 overexpression in Hepa 1-6 cells. S100A11 interacted with HDAC6 to inhibit its activity, leading to the release and activation of FOXO1. Under S100A11 overexpression, the inhibition of FOXO1 and autophagy could alleviate the activated autophagy as well as up-regulated lipogenic genes. Both FOXO1 and autophagy inhibition and Dgat2 deletion could reduce liver cell lipid accumulation significantly. CONCLUSIONS: A high-fat diet promotes liver S100A11 expression, which may interact with HDAC6 to block its binding to FOXO1, releasing or increasing the acetylation of FOXO1, thus activating autophagy and lipogenesis, and accelerating lipid accumulation and liver steatosis. These findings indicate a completely novel S100A11-HDAC6-FOXO1 axis in the regulation of autophagy and liver steatosis, providing potential possibilities for the treatment of NAFLD.


Subject(s)
Forkhead Box Protein O1/metabolism , Non-alcoholic Fatty Liver Disease/genetics , S100 Proteins/metabolism , Animals , Autophagy/genetics , Cell Line, Tumor , Datasets as Topic , Diet, High-Fat/adverse effects , Disease Models, Animal , Hepatocytes , Humans , Lipogenesis/genetics , Liver/pathology , Mice , Mice, Transgenic , Non-alcoholic Fatty Liver Disease/pathology , S100 Proteins/genetics , Tupaiidae , Up-Regulation
10.
Nat Commun ; 9(1): 1195, 2018 03 22.
Article in English | MEDLINE | ID: mdl-29567958

ABSTRACT

The primary function of the nucleolus is ribosome biogenesis, which is an extremely energetically expensive process. Failures in ribosome biogenesis cause nucleolar stress with an altered energy status. However, little is known about the underlying mechanism linking nucleolar stress to energy metabolism. Here we show that nucleolar stress is triggered by inactivation of RSKS-1 (ribosomal protein S6 kinase), RRP-8 (ribosomal RNA processing 8), and PRO-2/3 (proximal proliferation), all of which are involved in ribosomal RNA processing or inhibition of rDNA transcription by actinomycin D (AD), leading to excessive lipid accumulation in Caenorhabditis elegans. The transcription factor PHA-4/FoxA acts as a sensor of nucleolar stress to bind to and transactivate the expression of the lipogenic genes pod-2 (acetyl-CoA carboxylase), fasn-1 (fatty acid synthase), and dgat-2 (diacylglycerol O-acyltransferase 2), consequently promoting lipid accumulation. Importantly, inactivation of pha-4 or dgat-2 is sufficient to abolish nucleolar stress-induced lipid accumulation and prolonged starvation survival. The results revealed a distinct PHA-4-mediated lipogenesis pathway that senses nucleolar stress and shifts excessive energy for storage as fat.

11.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1863(3): 235-246, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29237573

ABSTRACT

Unsaturated fatty acids (UFAs) play crucial roles in living organisms regarding development, energy metabolism, stress resistance, etc. The biosynthesis of UFAs starts from the introduction of the first double bond by stearoyl-CoA desaturase (SCD), converting saturated fatty acids (SFAs) to monounsaturated fatty acids (MUFAs). This desaturation is considered to be an aerobic process that requires cytochrome b5 reductase, cytochrome b5 and SCD. However, this enzyme system remains elusive in Caenorhabditis elegans. Here, we show that inactivation by RNAi knockdown or mutation (gk442189) of putative cytochrome b5 genes cytb-5.1 led to reduced conversion of C18:0 to C18:1(n-9) by SCD desaturases FAT-6/7 in C. elegans. On the contrary, cytb-5.2RNAi and cytb-5.2(gk113588) mutant worms showed decreased conversion of C16:0 to C16:1(n-7) by FAT-5 desaturase. Dietary supplementation with C18:1(n-9) and C18:2(n-6) also showed that CYTB-5.1 is likely required for the activity of FAT-6/7 desaturases, but not for FAT-1 to FAT-4 desaturases. Interestingly, co-immunoprecipitation (Co-IP) demonstrated that either FAT-7 or FAT-5 has ability to interact with both CYTB-5.1 and CYTB-5.2. Moreover, RNAi knockdown of cytb-5.1 upregulates the transcriptional and translational expression of fat-5 to fat-7, which may be due to the feedback induction by reduced C18:1(n-9) and downstream fatty acids. Furthermore, both CYTB-5.1 and CYTB-5.2 are involved in fat accumulation, fertility and lifespan in worms, which may be independent of changes in fatty acid compositions. Collectively, these findings for the first time reveal the differential regulation of various SCDs by distinct cytochrome b5 CYTB-5.1 and CYTB-5.2 in the biosynthesis of UFAs in C. elegans.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/enzymology , Cytochromes b5/metabolism , Gene Expression Regulation, Enzymologic/physiology , Stearoyl-CoA Desaturase/biosynthesis , Animals , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Cytochromes b5/genetics , Fertility/physiology , Longevity/physiology , Stearoyl-CoA Desaturase/genetics
12.
J Lipid Res ; 58(9): 1845-1854, 2017 09.
Article in English | MEDLINE | ID: mdl-28710073

ABSTRACT

Maintenance of lipid homeostasis is crucial for cells in response to lipid requirements or surplus. The SREBP transcription factors play essential roles in regulating lipid metabolism and are associated with many metabolic diseases. However, SREBP regulation of lipid metabolism is still not completely understood. Here, we showed that reduction of SBP-1, the only homolog of SREBPs in Caenorhabditis elegans, surprisingly led to a high level of zinc. On the contrary, zinc reduction by mutation of sur-7, encoding a member of the cation diffusion facilitator (CDF) family, restored the fat accumulation and fatty acid profile of the sbp-1(ep79) mutant. Zinc reduction resulted in iron overload, which thereby directly activated the conversion activity of stearoyl-CoA desaturase (SCD), a main target of SREBP, to promote lipid biosynthesis and accumulation. However, zinc reduction reversely repressed SBP-1 nuclear translocation and further downregulated the transcription expression of SCD for compensation. Collectively, we revealed zinc-mediated regulation of the SREBP-SCD axis in lipid metabolism, distinct from the negative regulation of SREBP-1 or SREBP-2 by phosphatidylcholine or cholesterol, respectively, thereby providing novel insights into the regulation of lipid homeostasis.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/metabolism , Lipid Metabolism , Stearoyl-CoA Desaturase/metabolism , Sterol Regulatory Element Binding Protein 1/metabolism , Transcription Factors/metabolism , Zinc/metabolism , Adipose Tissue/metabolism , Animals , Caenorhabditis elegans/enzymology , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Genomics , Mutation , Sterol Regulatory Element Binding Protein 1/genetics , Transcription Factors/genetics
13.
Molecules ; 21(10)2016 Oct 17.
Article in English | MEDLINE | ID: mdl-27763516

ABSTRACT

Due to misbalanced energy surplus and expenditure, obesity has become a common chronic disorder that is highly associated with many metabolic diseases. Pu-erh tea, a traditional Chinese beverage, has been believed to have numerous health benefits, such as anti-obesity. However, the underlying mechanisms of its anti-obesity effect are yet to be understood. Here, we take the advantages of transcriptional profile by RNA sequencing (RNA-Seq) to view the global gene expression of Pu-erh tea. The model organism Caenorhabditis elegans was treated with different concentrations of Pu-erh tea water extract (PTE, 0 g/mL, 0.025 g/mL, and 0.05 g/mL). Compared with the control, PTE indeed decreases lipid droplets size and fat accumulation. The high-throughput RNA-Sequence technique detected 18073 and 18105 genes expressed in 0.025 g/mL and 0.05 g/mL PTE treated groups, respectively. Interestingly, the expression of the vitellogenin family (vit-1, vit-2, vit-3, vit-4 and vit-5) was significantly decreased by PTE, which was validated by qPCR analysis. Furthermore, vit-1(ok2616), vit-3(ok2348) and vit-5(ok3239) mutants are insensitive to PTE triggered fat reduction. In conclusion, our transcriptional profile by RNA-Sequence suggests that Pu-erh tea lowers the fat accumulation primarily through repression of the expression of vit(vitellogenin) family, in addition to our previously reported (sterol regulatory element binding protein) SREBP-SCD (stearoyl-CoA desaturase) axis.


Subject(s)
Caenorhabditis elegans/genetics , Drugs, Chinese Herbal/pharmacology , Gene Expression Profiling/methods , Sequence Analysis, RNA/methods , Vitellogenins/genetics , Adipose Tissue/drug effects , Animals , Caenorhabditis elegans/drug effects , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/genetics , Drugs, Chinese Herbal/analysis , Gene Expression Regulation/drug effects , Multigene Family/drug effects , Mutation , Teas, Herbal/analysis
14.
Nanotechnology ; 27(31): 315602, 2016 Aug 05.
Article in English | MEDLINE | ID: mdl-27345100

ABSTRACT

Silver and cobalt co-doped ZnS (ZnS:Ag,Co) water-soluble afterglow nanoparticles were synthesized using a wet chemistry method followed by aging at room temperature. The nanoparticles had a cubic zinc blende structure with average sizes of approximately 4 nm and emitted a blue fluorescence emission centered at 441 nm due to radiative transitions from surface defects to Ag(+) luminescent centers. Intense afterglow emission peaking at 475 nm from the obtained nanoparticles was observed and was red-shifted compared to the fluorescence emission peak. X-ray photoelectron spectroscopy revealed a large increase of O/S ratio, indicating a surface oxidation process during aging. The S vacancies produced accordingly may contribute to form more electron traps and enhance afterglow. The ZnS:Ag,Co afterglow nanoparticles have a very low dark-toxicity and are applied as a light source for photodynamic therapy activation by conjugating with protoporphyrin together. Our preliminary study has shown that the ZnS:Ag,Co afterglow nanoparticles can significantly reduce the x-ray dosage used in activation and thus may be a very promising candidate for future x-ray excited photodynamic therapy in deep cancer treatment.

15.
Genetics ; 203(1): 241-53, 2016 05.
Article in English | MEDLINE | ID: mdl-27017620

ABSTRACT

The trace element iron is crucial for living organisms, since it plays essential roles in numerous cellular functions. Systemic iron overload and the elevated level of ferritin, a ubiquitous intracellular protein that stores and releases iron to maintain the iron homeostasis in cells, has long been epidemiologically associated with obesity and obesity-related diseases. However, the underlying mechanisms of this association remain unclear. Here, using Caenorhabditis elegans, we show that iron overload induces the expression of sgk-1, encoding the serum and glucocorticoid-inducible kinase, to promote the level of ferritin and fat accumulation. Mutation of cyp-23A1, encoding a homolog of human cytochrome P450 CYP7B1 that is related to neonatal hemochromatosis, further enhances the elevated expression of ftn-1, sgk-1, and fat accumulation. sgk-1 positively regulates the expression of acs-20 and vit-2, genes encoding homologs of the mammalian FATP1/4 fatty acid transport proteins and yolk lipoproteins, respectively, to facilitate lipid uptake and translocation for storage under iron overload. This study reveals a completely novel pathway in which sgk-1 plays a central role to synergistically regulate iron and lipid homeostasis, offering not only experimental evidence supporting a previously unverified link between iron and obesity, but also novel insights into the pathogenesis of iron and obesity-related human metabolic diseases.


Subject(s)
Adiposity/genetics , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Ferritins/genetics , Gene Expression Regulation , Iron Overload/genetics , Iron Overload/metabolism , Iron/metabolism , Animals , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Disease Models, Animal , Fatty Acid Transport Proteins/genetics , Fatty Acid Transport Proteins/metabolism , Ferritins/metabolism , Lipid Metabolism , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Protein Transport
16.
Biochim Biophys Acta ; 1861(4): 310-9, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26806391

ABSTRACT

Polyunsaturated fatty acids (PUFAs) are fatty acids with backbones containing more than one double bond, which are introduced by a series of desaturases that insert double bonds at specific carbon atoms in the fatty acid chain. It has been established that desaturases need flavoprotein-NADH-dependent cytochrome b5 reductase (simplified as cytochrome b5 reductase) and cytochrome b5 to pass through electrons for activation. However, it has remained unclear how this multi-enzyme system works for distinct desaturases. The model organism Caenorhabditis elegans contains seven desaturases (FAT-1, -2, -3, -4, -5, -6, -7) for the biosynthesis of PUFAS, providing an excellent model in which to characterize different desaturation reactions. Here, we show that RNAi inactivation of predicted cytochrome b5 reductases hpo-19 and T05H4.4 led to increased levels of C18:1n-9 but decreased levels of PUFAs, small lipid droplets, decreased fat accumulation, reduced brood size and impaired development. Dietary supplementation with different fatty acids showed that HPO-19 and T05H4.4 likely affect the activity of FAT-1, FAT-2, FAT-3, and FAT-4 desaturases, suggesting that these four desaturases use the same cytochrome b5 reductase to function. Collectively, these findings indicate that cytochrome b5 reductase HPO-19/T05H4.4 is required for desaturation to biosynthesize PUFAs in C. elegans.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/enzymology , Cytochrome-B(5) Reductase/metabolism , Fatty Acid Desaturases/metabolism , Fatty Acids, Unsaturated/biosynthesis , Animals , Animals, Genetically Modified , Caenorhabditis elegans/genetics , Caenorhabditis elegans/growth & development , Caenorhabditis elegans Proteins/genetics , Cytochrome-B(5) Reductase/genetics , Fatty Acid Desaturases/genetics , Lipid Droplets/metabolism , Reproduction , Time Factors
17.
Photodiagnosis Photodyn Ther ; 13: 244-254, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26253653

ABSTRACT

Afterglow nanoparticles have been widely investigated as new agents for cancer imaging and as a light source for photodynamic activation for cancer treatment. For both applications, the targeting of the afterglow nanoparticles to tumor cells is an important and challenging issue. Here we report the strategies for targeting Sr3MgSi2O8:Eu(2+),Dy(3+) afterglow nanoparticles to tumor cells by conjugating with variety of targeting molecules such as folic acid, RGD peptide, and R-11 peptide. For folic acid targeting, experimental observations were conducted on PC-3 cells (folate receptor negative), MCF-7 (folate receptor positive), and KB cells (folate receptor positive) to compare the cellular uptake and confirm targeted delivery. For the cyclic RGDfK peptide, experiments were carried out on the integrin αvß3 positive MDA-MB-231 breast cancer cell line and the integrin αvß3 negative MCF-7 breast cancer cell lines in order to compare the cellular uptakes. As for R11-SH peptide, cellular uptake of the afterglow nanoparticles was observed on LNCaP and PC3 prostate cancer cell lines. All the observations showed that the cellular uptakes of the nanoparticles were enhanced by conjugation to variety of targeting molecules which are specific for breast and prostate cancer cells.


Subject(s)
Luminescent Agents/chemical synthesis , Luminescent Agents/pharmacokinetics , Nanoconjugates/chemistry , Nanoparticles/chemistry , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Cell Line, Tumor , Humans , Materials Testing , Nanoconjugates/ultrastructure , Nanoparticles/ultrastructure
18.
Clin Exp Pharmacol Physiol ; 42(9): 940-949, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26175075

ABSTRACT

It has been well established that neurogenic inflammation is one of the major pathological processes underlying inflammatory pain, but there are few effective anti-inflammatory drugs to alleviate such pain. The present study shows that minocycline, a widely used glial activation inhibitor, is effective in reducing neurogenic inflammation. Patch-clamp recordings showed that small sized dorsal root ganglion (DRG) neurons were dramatically excited following intradermal capsaicin injection in the rat hind paw, evidenced by decreased rheobase and membrane threshold. Pretreatment with minocycline (30 mg/kg for 1 day, intraperitoneal injection) blocked the increased neuronal excitability. Western blot and immunostaining of DRG revealed the activation of satellite glial cells (SGCs) following capsaicin injection. The up-regulation of glial fibrillary acidic protein (GFAP) was significantly inhibited by minocycline pre-administration. Measurement of tumor necrosis factor α (TNF-α) and its receptor, TNF-α receptor 1 (TNFR1), showed that minocycline mainly blocked the up-regulation of TNF-α in SGCs and TNFR1s in neurons following capsaicin injection. The pivotal role of TNF-α in neurogenic inflammation was further supported by the findings that incubation DRG with TNF-α mimicked the increased excitability of DRG neurons induced by capsaicin injection, and that TNF-α application enhanced cutaneous vasodilation in the hind paws induced by antidromic electrical stimulation of dorsal roots. Based on these results, we propose that minocycline is a potential therapeutic drug that can reduce neuronal excitability and neurogenic inflammation by working on SGCs to inhibit the expression of TNF-α.

19.
Photodiagnosis Photodyn Ther ; 12(2): 258-66, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25636780

ABSTRACT

Molecular modification of protoporphyrin IX (PpIX) was conducted to improve its water solubility and therapeutic performance for photodynamic therapy. The carboxylic acid and the two nitrogen atoms in the core of PpIX molecule were protonated following by conjugation with 3-aminopropyl triethoxysilane (APTES). Then, folic acid (FA) was conjugated to the APTES-coated PpIX (MPpIX) through chemical bonding between FA and protonated PpIX. The results showed that APTES coating can stabilize PpIX and increase its water solubility. Consequently, this leads to the enhancement in luminescence and singlet oxygen production. Upon X-ray irradiation, singlet oxygen can be detected in the MPpIX but not in PpIX. This means that MPpIX can be used for deep cancer treatment as X-ray can penetrate deeply into tissue. Molecular modification also reduces the dark toxicity of PPIX and increases their cell uptake. All these traits indicate that the Molecular modification of PpIX may potentially improve the efficacy of photodynamic therapy for cancer treatment.


Subject(s)
Photochemotherapy/methods , Photosensitizing Agents/chemistry , Photosensitizing Agents/pharmacology , Protoporphyrins/chemistry , Protoporphyrins/pharmacology , Cell Line , Dose-Response Relationship, Drug , Drug Stability , Folic Acid/chemistry , Humans , Photosensitizing Agents/administration & dosage , Propylamines/chemistry , Protoporphyrins/administration & dosage , Silanes/chemistry , Singlet Oxygen/metabolism , Solubility , Structure-Activity Relationship
20.
PLoS One ; 10(2): e0113815, 2015.
Article in English | MEDLINE | ID: mdl-25659129

ABSTRACT

Consumption of Pu-erh has been reported to result in numerous health benefits, but the mechanisms underlying purported weight-loss and lowering of lipid are poorly understood. Here, we used the nematode Caenorhaditis elegans to explore the water extract of Pu-erh tea (PTE) functions to reduce fat storage. We found that PTE down-regulates the expression of the master fat regulator SBP-1, a homologue of sterol regulatory element binding protein (SREBP) and its target stearoyl-CoA desaturase (SCD), a key enzyme in fat biosynthesis, leading to an increased ratio of stearic acid (C18:0) to oleic acid (C18:1n-9), and subsequently decreased fat storage. We also found that both the pharyngeal pumping rate and food uptake of C. elegans decreased with exposure to PTE. Collectively, these results provide an experimental basis for explaining the ability of Pu-erh tea in promoting inhibition of food uptake and the biosynthesis of fat via SBP-1 and SCD, thereby reducing fat storage.


Subject(s)
Caenorhabditis elegans Proteins/biosynthesis , Caenorhabditis elegans/metabolism , Drugs, Chinese Herbal/pharmacology , Fats/metabolism , Stearoyl-CoA Desaturase/biosynthesis , Tea/chemistry , Transcription Factors/biosynthesis , Animals , Caenorhabditis elegans/genetics , Drugs, Chinese Herbal/chemistry , Humans , Response Elements/physiology
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