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1.
Nat Commun ; 15(1): 4915, 2024 Jun 08.
Article in English | MEDLINE | ID: mdl-38851747

ABSTRACT

The bioavailability of nicotinamide adenine dinucleotide (NAD) is vital for skeletal muscle health, yet the mechanisms or signals regulating NAD homeostasis remain unclear. Here, we uncover a pathway connecting peripheral glucose sensing to the modulation of muscle NAD through TAS1R2, the sugar-sensing G protein-coupled receptor (GPCR) initially identified in taste perception. Muscle TAS1R2 receptor stimulation by glucose and other agonists induces ERK1/2-dependent phosphorylation and activation of poly(ADP-ribose) polymerase1 (PARP1), a major NAD consumer in skeletal muscle. Consequently, muscle-specific deletion of TAS1R2 (mKO) in male mice suppresses PARP1 activity, elevating NAD levels and enhancing mitochondrial capacity and running endurance. Plasma glucose levels negatively correlate with muscle NAD, and TAS1R2 receptor deficiency enhances NAD responses across the glycemic range, implicating TAS1R2 as a peripheral energy surveyor. These findings underscore the role of GPCR signaling in NAD regulation and propose TAS1R2 as a potential therapeutic target for maintaining muscle health.


Subject(s)
Glucose , Homeostasis , Muscle, Skeletal , NAD , Receptors, G-Protein-Coupled , Animals , Muscle, Skeletal/metabolism , NAD/metabolism , Receptors, G-Protein-Coupled/metabolism , Receptors, G-Protein-Coupled/genetics , Male , Glucose/metabolism , Mice , Mice, Knockout , Humans , Mitochondria/metabolism , Mice, Inbred C57BL , Signal Transduction , Phosphorylation
2.
FASEB J ; 38(11): e23709, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38809700

ABSTRACT

Brown adipose tissue (BAT) is correlated to cardiovascular health in rodents and humans, but the physiological role of BAT in the initial cardiac remodeling at the onset of stress is unknown. Activation of BAT via 48 h cold (16°C) in mice following transverse aortic constriction (TAC) reduced cardiac gene expression for LCFA uptake and oxidation in male mice and accelerated the onset of cardiac metabolic remodeling, with an early isoform shift of carnitine palmitoyltransferase 1 (CPT1) toward increased CPT1a, reduced entry of long chain fatty acid (LCFA) into oxidative metabolism (0.59 ± 0.02 vs. 0.72 ± 0.02 in RT TAC hearts, p < .05) and increased carbohydrate oxidation with altered glucose transporter content. BAT activation with TAC reduced early hypertrophic expression of ß-MHC by 61% versus RT-TAC and reduced pro-fibrotic TGF-ß1 and COL3α1 expression. While cardiac natriuretic peptide expression was yet to increase at only 3 days TAC, Nppa and Nppb expression were elevated in Cold TAC versus RT TAC hearts 2.7- and 2.4-fold, respectively. Eliminating BAT thermogenic activation with UCP1 KO mice eliminated differences between Cold TAC and RT TAC hearts, confirming effects of BAT activation rather than autonomous cardiac responses to cold. Female responses to BAT activation were blunted, with limited UCP1 changes with cold, partly due to already activated BAT in females at RT compared to thermoneutrality. These data reveal a previously unknown physiological mechanism of UCP1-dependent BAT activation in attenuating early cardiac hypertrophic and profibrotic signaling and accelerating remodeled metabolic activity in the heart at the onset of cardiac stress.


Subject(s)
Adipose Tissue, Brown , Fibrosis , Uncoupling Protein 1 , Animals , Adipose Tissue, Brown/metabolism , Mice , Male , Uncoupling Protein 1/metabolism , Fibrosis/metabolism , Carnitine O-Palmitoyltransferase/metabolism , Carnitine O-Palmitoyltransferase/genetics , Mice, Inbred C57BL , Cardiomegaly/metabolism , Cardiomegaly/pathology , Myocardium/metabolism , Myocardium/pathology , Stress, Physiological , Ventricular Remodeling/physiology , Mice, Knockout , Cold Temperature
3.
Toxicol Appl Pharmacol ; 478: 116699, 2023 11 01.
Article in English | MEDLINE | ID: mdl-37777120

ABSTRACT

Enzalutamide is an androgen receptor (AR) antagonist commonly used in the treatment of prostate cancer (CaP). However, due to the potential toxicity and development of resistance associated with Enzalutamide-based therapy, there is a need to explore additional compounds that can enhance its therapeutic effectiveness while minimizing toxicity. Lupeol is a pharmacologically active triterpene having anticancer effects. The objective of this study was to explore Lupeol's potential in enhancing the chemosensitivity of chemoresistant CaP cells to Enzalutamide in vitro and in a mouse model. To test our hypothesis, we performed cell viability and luciferase reporter gene assay, flow cytometry, animal studies, and histopathological analysis. Finally, we analyzed the change in selective metabolites in the prostate tissue by LCMS. Results demonstrated that a combination of Lupeol and Enzalutamide could better (i) suppress the Cancer Stem Cells (CSCs) and chemoresistant cells (PTEN-CaP8 and PC3) viability and migration, (ii) increase cell cycle arrest, (iii) inhibit the transcriptional activity of AR, c-MYC, c-FLIP, and TCF (iv) inhibit tumor growth in a mouse model (v) protect Enzalutamide-induced adverse effects in prostate glands and gut tissue (vi) decrease levels of testosterone and methionine metabolites. In conclusion, Lupeol enhances the pharmacological efficacy of Enzalutamide and reduces the adverse effects. Thus, Lupeol could be a promising adjuvant for improving Enzalutamide-based treatment outcomes and warrant further research.


Subject(s)
Prostatic Neoplasms, Castration-Resistant , Receptors, Androgen , Humans , Male , Animals , Mice , Receptors, Androgen/genetics , Prostate/pathology , Cell Line, Tumor , Androgen Receptor Antagonists/pharmacology , Androgen Receptor Antagonists/therapeutic use , Nitriles/pharmacology , Pentacyclic Triterpenes/pharmacology , Drug Resistance, Neoplasm , Prostatic Neoplasms, Castration-Resistant/drug therapy
4.
JACC Basic Transl Sci ; 8(4): 422-435, 2023 Apr.
Article in English | MEDLINE | ID: mdl-37138801

ABSTRACT

Western diet (WD) impairs glucose tolerance and cardiac lipid dynamics, preceding heart failure with reduced ejection fraction (HFrEF) in mice. Unlike diabetic db/db mice with high cardiac triglyceride (TG) and rapid TG turnover, WD mice had high TG but slowed turnover, reducing lipolytic PPAR⍺ activation. WD deranged cardiac TG dynamics by imbalancing synthesis and lipolysis, with low cardiac TG lipase (ATGL), low ATGL co-activator, and high ATGL inhibitory peptide. By 24 weeks of WD, hearts shifted from diastolic dysfunction to diastolic dysfunction with HFrEF with decreases in GLUT4 and exogenous glucose oxidation and elevated ß-hydroxybutyrate dehydrogenase 1 without increasing ketone oxidation.

5.
J Clin Invest ; 133(9)2023 05 01.
Article in English | MEDLINE | ID: mdl-36927960

ABSTRACT

During the development of heart failure (HF), the capacity for cardiomyocyte (CM) fatty acid oxidation (FAO) and ATP production is progressively diminished, contributing to pathologic cardiac hypertrophy and contractile dysfunction. Receptor-interacting protein 140 (RIP140, encoded by Nrip1) has been shown to function as a transcriptional corepressor of oxidative metabolism. We found that mice with striated muscle deficiency of RIP140 (strNrip1-/-) exhibited increased expression of a broad array of genes involved in mitochondrial energy metabolism and contractile function in heart and skeletal muscle. strNrip1-/- mice were resistant to the development of pressure overload-induced cardiac hypertrophy, and CM-specific RIP140-deficient (csNrip1-/-) mice were protected against the development of HF caused by pressure overload combined with myocardial infarction. Genomic enhancers activated by RIP140 deficiency in CMs were enriched in binding motifs for transcriptional regulators of mitochondrial function (estrogen-related receptor) and cardiac contractile proteins (myocyte enhancer factor 2). Consistent with a role in the control of cardiac fatty acid oxidation, loss of RIP140 in heart resulted in augmented triacylglyceride turnover and fatty acid utilization. We conclude that RIP140 functions as a suppressor of a transcriptional regulatory network that controls cardiac fuel metabolism and contractile function, representing a potential therapeutic target for the treatment of HF.


Subject(s)
Heart Failure , Nuclear Receptor Interacting Protein 1 , Animals , Mice , Cardiomegaly/metabolism , Energy Metabolism/genetics , Fatty Acids/metabolism , Heart Failure/genetics , Heart Failure/metabolism , Myocytes, Cardiac/metabolism , Nuclear Receptor Interacting Protein 1/genetics , Nuclear Receptor Interacting Protein 1/metabolism
6.
Res Sq ; 2023 Feb 09.
Article in English | MEDLINE | ID: mdl-36798161

ABSTRACT

Muscle fitness and mass deteriorate under the conditions of obesity and aging for reasons yet to be fully elucidated. Herein, we describe a novel pathway linking peripheral nutrient sensing and skeletal muscle function through the sweet taste receptor TAS1R2 and the involvement of ERK2-PARP1-NAD signaling axis. Muscle-specific deletion of TAS1R2 (mKO) in mice produced elevated NAD levels due to suppressed PARP1 activity, improved mitochondrial function, increased muscle mass and strength, and prolonged running endurance. Deletion of TAS1R2 in obese or aged mice also ameliorated the decline in muscle mass and fitness arising from these conditions. Remarkably, partial loss-of-function of TAS1R2 (rs35874116) in older, obese humans recapitulated the healthier muscle phenotype displayed by mKO mice in response to exercise training. Our findings show that inhibition of the TAS1R2 signaling in skeletal muscle is a promising therapeutic approach to preserve muscle mass and function.

7.
Semin Cancer Biol ; 83: 166-176, 2022 08.
Article in English | MEDLINE | ID: mdl-33220458

ABSTRACT

Both genetic and epigenetic mechanisms intimately regulate cancer development and chemoresistance. Different genetic alterations are observed in multiple genes, and most are irreversible. Aside from genetic alterations, epigenetic alterations play a crucial role in cancer. The reversible nature of epigenetic modifications makes them an attractive target for cancer prevention and therapy. Specific epigenetic alteration is also being investigated as a potential biomarker in multiple cancers. c-MYC is one of the most important transcription factors that are centrally implicated in multiple types of cancer cells reprogramming, proliferation, and chemoresistance. c-MYC shows not only genetic alterations but epigenetic changes in multiple cancers. It has been observed that epigenome aberrations can reversibly alter the expression of c-MYC, both transcriptional and translational levels. Understanding the underlying mechanism of the epigenetic alterations of c-MYC, that has its role in multiple levels of cancer pathogenesis, can give a better understanding of various unresolved questions regarding cancer. Recently, some researchers reported that targeting the epigenetic modifiers of c-MYC can successfully inhibit cancer cell proliferation, sensitize the chemoresistant cells, and increase the patient survival rate. As c-MYC is an important transcription factor, epigenetic therapy might be one of the best alternatives for the conventional therapies that assumes the "one-size-fits-all" role. It can also increase the precision of targeting and enhance the effectiveness of treatments among various cancer subtypes. In this review, we highlighted the role of epigenetically modified c-MYC in cancer cell reprogramming, progression, and chemoresistance. We also summarize the potential therapeutic approaches to target these modifications for the prevention of cancer development and chemoresistant phenotypes.


Subject(s)
Cellular Reprogramming , Neoplasms , Cellular Reprogramming/genetics , Drug Resistance, Neoplasm/genetics , Epigenesis, Genetic , Genes, myc , Humans , Neoplasms/drug therapy , Neoplasms/genetics , Neoplasms/pathology , Proto-Oncogene Proteins c-myc/genetics , Proto-Oncogene Proteins c-myc/metabolism , Transcription Factors/genetics
8.
Epigenomics ; 13(23): 1885-1900, 2021 12.
Article in English | MEDLINE | ID: mdl-34693722

ABSTRACT

The transcription factor NANOG regulates self-renewal and pluripotency in embryonic cells, and its downregulation leads to cell differentiation. Recent studies have linked upregulation of NANOG in various cancers and the regulation of expression of different molecules, and vice versa, to induce proliferation, metastasis, invasion and chemoresistance. Thus NANOG is an oncogene that functions by inducing stem cells' circuitries and heterogeneity in cancers. Understanding NANOG's role in various cancers may lead to it becoming a therapeutic target to halt cancer progression. The NANOG network can also be targeted to resensitize resistant cancer cells to conventional therapies. The current review focuses on NANOG regulation in the various signaling networks leading to cancer progression and chemoresistance, and highlights the therapeutic aspect of targeting NANOG in various cancers.


Lay abstract NANOG is a gene that is mainly expressed during development of the embryo. In adult tissues, NANOG is hardly expressed. In embryonal cells, NANOG is responsible for generating stem cells. Once the cells are differentiated into their specific function, they no longer need this renewing property. So expression of NANOG in differentiated 'adult' cells is harmful as it helps tumor cells to grow. NANOG expression also enables the tumor cells to keep on evolving their microenvironment, thus making it difficult for conventional therapy to destroy them. This review highlights the factors that influence NANOG's expression in cancer progression and chemoresistance and how it can be targeted for therapy.


Subject(s)
Nanog Homeobox Protein/metabolism , Neoplasms/metabolism , Animals , Carcinogenesis/metabolism , Drug Resistance, Neoplasm , Epigenesis, Genetic , Humans , Nanog Homeobox Protein/genetics , Neoplasms/drug therapy , Neoplasms/prevention & control
9.
Circulation ; 143(18): 1797-1808, 2021 05 04.
Article in English | MEDLINE | ID: mdl-33601938

ABSTRACT

BACKGROUND: The failing heart is energy starved with impaired oxidation of long-chain fatty acids (LCFAs) at the level of reduced CPT1 (carnitine palmitoyltransferase 1) activity at the outer mitochondrial membrane. Recent work shows elevated ketone oxidation in failing hearts as an alternate carbon source for oxidative ATP generation. We hypothesized that another short-chain carbon source, short-chain fatty acids (SCFAs) that bypass carnitine palmitoyltransferase 1, could similarly support energy production in failing hearts. METHODS: Cardiac hypertrophy and dysfunction were induced in rats by transverse-aortic constriction (TAC). Fourteen weeks after TAC or sham operation, isolated hearts were perfused with either the 4 carbon, 13C-labeled ketone (D3-hydroxybutyrate) or the 4 carbon, 13C-labeled SCFA butyrate in the presence of glucose and the LCFA palmitate. Oxidation of ketone and SCFA was compared by in vitro 13C nuclear magnetic resonance spectroscopy, as was the capacity for short-chain carbon sources to compensate for impaired LCFA oxidation in the hypertrophic heart. Adaptive changes in enzyme expression and content for the distinct pathways of ketone and SCFA oxidation were examined in both failing rat and human hearts. RESULTS: TAC produced pathological hypertrophy and increased the fractional contributions of ketone to acetyl coenzyme-A production in the tricarboxylic acid cycle (0.60±0.02 sham ketone versus 0.70±0.02 TAC ketone; P<0.05). However, butyrate oxidation in failing hearts was 15% greater (0.803±0.020 TAC SCFA) than ketone oxidation. SCFA was also more readily oxidized than ketone in sham hearts by 15% (0.693±0.020 sham SCFA). Despite greater SFCA oxidation, TAC did not change short-chain acyl coenzyme-A dehydrogenase content. However, failing hearts of humans and the rat model both contain significant increases in acyl coenzyme-A synthetase medium-chain 3 enzyme gene expression and protein content. The increased oxidation of SCFA and ketones occurred at the expense of LCFA oxidation, with LCFA contributing less to acetyl coenzyme-A production in failing hearts perfused with SCFA (0.190±0.012 TAC SCFA versus 0.3163±0.0360 TAC ketone). CONCLUSIONS: SCFAs are more readily oxidized than ketones in failing hearts, despite both bypassing reduced CPT1 activity and represent an unexplored carbon source for energy production in failing hearts.


Subject(s)
Fatty Acids, Volatile/metabolism , Heart Failure/physiopathology , Ketones/metabolism , Animals , Disease Models, Animal , Humans , Male , Oxidation-Reduction , Rats , Rats, Sprague-Dawley
10.
ACS Omega ; 5(25): 15218-15228, 2020 Jun 30.
Article in English | MEDLINE | ID: mdl-32637795

ABSTRACT

New organometallic drug candidates [Ph2Sn(HL)], 1, and [Ru(η6--p-cymene)(HL)Cl], 2, were designed and synthesized by in situ reaction of a Schiff base ligand (HL) and diphenyltin dichloride and [RuCl2(p-cymene)]2, respectively. The drug candidates 1 and 2 have been characterized by spectroscopic methods (Fourier-transform infrared spectroscopy, UV-vis, and 1H/13C NMR), elemental analysis, and single X-ray crystallographic studies (in case of 1). The ground-state geometry optimization of 1 and 2 was performed by density functional theory calculations. The interaction of 1 and 2 with tRNA was assessed by absorption spectroscopy, cyclic voltammetry, circular dichroism, and ethidium bromide displacement assay using fluorescence emission spectroscopy to determine their potential to act as antitumor agents. The cytotoxicity of 1 and 2 was screened against human liver carcinoma (Huh7), prostate cancer (Du145), and the normal prostate cell line (PNT 2). The results implicated a dose-dependent growth inhibition of the two cancer cells at concentrations (2.5-15 µM) of 1 and 2 with the treatment after 48 h. Interestingly, 1 revealed good selective activity toward the liver cancer cell line (Huh7). Furthermore, both the drug candidates 1 and 2 were found to be nontoxic toward the PNT 2 normal cell line. These studies lay a paradigm for rational efficacious drug design for chemotherapeutic intervention in cancers using new tailored organometallic drug entities; organotin(IV) and organoruthenium(II) have been demonstrated to be viable for the safe administration and specific targeted drug uptake by the resistant cancerous cell lines at low intracellular concentrations.

11.
J Recept Signal Transduct Res ; 40(6): 605-612, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32476594

ABSTRACT

Recently, a pathogen has been identified as a novel coronavirus (SARS-CoV-2) and found to trigger novel pneumonia (COVID-19) in human beings and some other mammals. The uncontrolled release of cytokines is seen from the primary stages of symptoms to last acute respiratory distress syndrome (ARDS). Thus, it is necessary to find out safe and effective drugs against this deadly coronavirus as soon as possible. Here, we downloaded the three-dimensional model of NSP10/NSP16 methyltransferase (PDB-ID: 6w6l) and main protease (PDB-ID: 6lu7) of COVID-19. Using these molecular models, we performed virtual screening with our anti-viral, inti-infectious, and anti-protease compounds, which are attractive therapeutics to prevent infection of the COVID-19. We found that top screened compound binds with protein molecules with good dock score with the help of hydrophobic interactions and hydrogen bonding. We observed that protease complexed with Cyclocytidine hydrochloride (anti-viral and anti-cancer), Trifluridine (anti-viral), Adonitol, and Meropenem (anti-bacterial), and Penciclovir (anti-viral) bound with a good docking score ranging from -6.8 to -5.1 (Kcal/mol). Further, NSP10/NSP16 methyltransferase complexed with Telbivudine, Oxytetracycline dihydrate (anti-viral), Methylgallate (anti-malarial), 2-deoxyglucose and Daphnetin (anti-cancer) from the docking score of -7.0 to -5.7 (Kcal/mol). In conclusion, the selected compounds may be used as a novel therapeutic agent to combat this deadly pandemic disease, SARS-CoV-2 infection, but needs further experimental research.HighlightsNSP10/NSP16 methyltransferase and main protease complex of SARS CoV-2 bind with selected drugs.NSP10/NSP16 methyltransferase and protease interacted with drugs by hydrophobic interactions.Compounds show good DG binging free energy with protein complexes.Ligands were found to follow the Lipinski rule of five.


Subject(s)
Antiviral Agents/chemistry , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , Viral Nonstructural Proteins/chemistry , Viral Regulatory and Accessory Proteins/chemistry , Acyclovir/analogs & derivatives , Acyclovir/chemistry , Acyclovir/therapeutic use , Ancitabine/chemistry , Ancitabine/therapeutic use , Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Betacoronavirus/pathogenicity , COVID-19 , Coronavirus Infections/virology , Drug Evaluation, Preclinical , Guanine , Humans , Meropenem/chemistry , Meropenem/therapeutic use , Methyltransferases , Models, Molecular , Molecular Docking Simulation , Pandemics , Pneumonia, Viral/virology , Protein Conformation/drug effects , Ribitol/chemistry , Ribitol/therapeutic use , SARS-CoV-2 , Trifluridine/chemistry , Trifluridine/therapeutic use , User-Computer Interface , Viral Nonstructural Proteins/antagonists & inhibitors , Viral Nonstructural Proteins/ultrastructure , Viral Regulatory and Accessory Proteins/antagonists & inhibitors , Viral Regulatory and Accessory Proteins/ultrastructure
12.
Curr Pharm Des ; 26(4): 455-465, 2020.
Article in English | MEDLINE | ID: mdl-31969092

ABSTRACT

BACKGROUND: The resistance of cancer cells to different therapies is one of the major stumbling blocks for successful cancer treatment. Various natural and pharmaceuticals drugs are unable to control drug-resistance cancer cell's growth. Also, chemotherapy and radiotherapy have several side effects and cannot apply to the patient in excess. In this context, chemosensitization to the therapy-resistant cells by non-toxic phytochemicals could be an excellent alternative to combat therapy-resistant cancers. OBJECTIVE: To review the currently available literature on chemosensitization of therapy resistance cancers by Lupeol for clinically approved drugs through targeting different cell signaling pathways. METHODS: We reviewed relevant published articles in PubMed and other search engines from 1999 to 2019 to write this manuscript. The key words used for the search were "Lupeol and Cancer", "Lupeol and Chemosensitization", "Lupeol and Cell Signaling Pathways", "Cancer Stem Cells and Lupeol" etc. The published results on the chemosensitization of Lupeol were compared and discussed. RESULTS: Lupeol chemosensitizes drug-resistant cancer cells for clinically approved drugs. Lupeol alone or in combination with approved drugs inhibits inflammation in different cancer cells through modulation of expression of IL-6, TNF-α, and IFN-γ. Lupeol, through altering the expression levels of BCL-2, BAX, Survivin, FAS, Caspases, and PI3K-AKT-mTOR signaling pathway, significantly induce cell deaths among therapy-resistant cells. Lupeol also modulates the molecules involved in cell cycle regulation such as Cyclins, CDKs, P53, P21, and PCNA in different cancer types. CONCLUSION: Lupeol chemosensitizes the therapy-resistant cancer cells for the treatment of various clinically approved drugs via modulating different signaling pathways responsible for chemoresistance cancer. Thus, Lupeol might be used as an adjuvant molecule along with clinically approved drugs to reduce the toxicity and increase the effectiveness.


Subject(s)
Neoplasms/drug therapy , Pentacyclic Triterpenes/pharmacology , Signal Transduction/drug effects , Apoptosis , Cell Line, Tumor , Drug Resistance, Neoplasm , Humans
14.
Cell Rep ; 24(11): 2919-2931, 2018 09 11.
Article in English | MEDLINE | ID: mdl-30208317

ABSTRACT

The major objective of this study was to understand the molecular basis of how sarcolipin uncoupling of SERCA regulates muscle oxidative metabolism. Using genetically engineered sarcolipin (SLN) mouse models and primary muscle cells, we demonstrate that SLN plays a crucial role in mitochondrial biogenesis and oxidative metabolism in muscle. Loss of SLN severely compromised muscle oxidative capacity without affecting fiber-type composition. Mice overexpressing SLN in fast-twitch glycolytic muscle reprogrammed mitochondrial phenotype, increasing fat utilization and protecting against high-fat diet-induced lipotoxicity. We show that SLN affects cytosolic Ca2+ transients and activates the Ca2+/calmodulin-dependent protein kinase II (CamKII) and PGC1α axis to increase mitochondrial biogenesis and oxidative metabolism. These studies provide a fundamental framework for understanding the role of sarcoplasmic reticulum (SR)-Ca2+ cycling as an important factor in mitochondrial health and muscle metabolism. We propose that SLN can be targeted to enhance energy expenditure in muscle and prevent metabolic disease.


Subject(s)
Muscle Proteins/metabolism , Muscle, Skeletal/metabolism , Proteolipids/metabolism , Animals , Calcium Signaling/physiology , Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism , Cells, Cultured , Energy Metabolism/physiology , Mice , Mice, Knockout , Mitochondria/metabolism , Muscle Fibers, Skeletal/metabolism , Muscle Proteins/genetics , Obesity/metabolism , Organelle Biogenesis , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism , Proteolipids/genetics , Signal Transduction/physiology , Thermogenesis/physiology
15.
R Soc Open Sci ; 5(5): 171042, 2018 May.
Article in English | MEDLINE | ID: mdl-29892344

ABSTRACT

Metamaterials are engineered materials that offer the flexibility to manipulate the incident waves leading to exotic applications such as cloaking, extraordinary transmission, sub-wavelength imaging and negative refraction. These concepts have largely been explored in the context of electromagnetic waves. Acoustic metamaterials, similar to their optical counterparts, demonstrate anomalous effective elastic properties. Recent developments have shown that coiling up the propagation path of acoustic wave results in effective elastic response of the metamaterial beyond the natural response of its constituent materials. The effective response of metamaterials is generally evaluated using the 'S' parameter retrieval method based on amplitude of the waves. The phase of acoustic waves contains information of wave pressure and particle velocity. Here, we show using finite-element methods that phase reversal of transmitted waves may be used to predict extreme acoustic properties in space coiling metamaterials. This change is the difference in the phase of the transmitted wave with respect to the incident wave. This method is simpler when compared with the more rigorous 'S' parameter retrieval method. The inferences drawn using this method have been verified experimentally for labyrinthine metamaterials by showing negative refraction for the predicted band of frequencies.

16.
Genome Announc ; 5(46)2017 Nov 16.
Article in English | MEDLINE | ID: mdl-29146861

ABSTRACT

Pantoea americana strain VS1, an extended-spectrum ß-lactamase-producing epibiont, was isolated from Magnolia grandiflora in central Florida, USA. Here, we report the de novo whole-genome sequence of this strain, which consists of a total of 191 contigs spanning 5,412,831 bp, with a GC content of 57.3% and comprising 4,836 predicted coding sequences.

17.
Biosci Rep ; 37(5)2017 Oct 31.
Article in English | MEDLINE | ID: mdl-28831023

ABSTRACT

There are two well-described thermogenic sites; brown adipose tissue (BAT) and skeletal muscle, which utilize distinct mechanisms of heat production. In BAT, mitochondrial metabolism is the molecular basis of heat generation, while it serves only a secondary role in supplying energy for thermogenesis in muscle. Here, we wanted to document changes in mitochondrial ultrastructure in these two tissue types based upon adaptation to mild (16°C) and severe (4°C) cold in mice. When reared at thermoneutrality (29°C), mitochondria in both tissues were loosely packed with irregular cristae. Interestingly, adaptation to even mild cold initiated ultrastructural remodeling of mitochondria including acquisition of more elaborate cristae structure in both thermogenic sites. The shape of mitochondria in the BAT remained mostly circular, whereas the intermyofibrilar mitochondria in the skeletal muscle became more elongated and tubular. The most dramatic remodeling of mitochondrial architecture was observed upon adaptation to severe cold. In addition, we report cold-induced alteration in levels of humoral factors: fibroblast growth factor 21 (FGF21), IL1α, peptide YY (PYY), tumor necrosis factor α (TNFα), and interleukin 6 (IL6) were all induced whereas both insulin and leptin were down-regulated. In summary, adaptation to cold leads to enhanced cristae formation in mitochondria in skeletal muscle as well as the BAT. Further, the present study indicates that circulating cytokines might play an important role in the synergistic recruitment of the thermogenic program including cross-talk between muscle and BAT.


Subject(s)
Adipose Tissue, Brown/physiology , Muscle, Skeletal/physiology , Thermogenesis , Acclimatization , Adipose Tissue, Brown/ultrastructure , Animals , Body Temperature , Cold Temperature , Cytokines/metabolism , Energy Metabolism , Male , Mice , Mice, Inbred C57BL , Mitochondria/metabolism , Mitochondria/ultrastructure , Muscle, Skeletal/ultrastructure
18.
J Biol Chem ; 292(40): 16616-16625, 2017 10 06.
Article in English | MEDLINE | ID: mdl-28794154

ABSTRACT

Thermogenesis is an important homeostatic mechanism essential for survival and normal physiological functions in mammals. Both brown adipose tissue (BAT) (i.e. uncoupling protein 1 (UCP1)-based) and skeletal muscle (i.e. sarcolipin (SLN)-based) thermogenesis processes play important roles in temperature homeostasis, but their relative contributions differ from small to large mammals. In this study, we investigated the functional interplay between skeletal muscle- and BAT-based thermogenesis under mild versus severe cold adaptation by employing UCP1-/- and SLN-/- mice. Interestingly, adaptation of SLN-/- mice to mild cold conditions (16 °C) significantly increased UCP1 expression, suggesting increased reliance on BAT-based thermogenesis. This was also evident from structural alterations in BAT morphology, including mitochondrial architecture, increased expression of electron transport chain proteins, and depletion of fat droplets. Similarly, UCP1-/- mice adapted to mild cold up-regulated muscle-based thermogenesis, indicated by increases in muscle succinate dehydrogenase activity, SLN expression, mitochondrial content, and neovascularization, compared with WT mice. These results further confirm that SLN-based thermogenesis is a key player in muscle non-shivering thermogenesis (NST) and can compensate for loss of BAT activity. We also present evidence that the increased reliance on BAT-based NST depends on increased autonomic input, as indicated by abundant levels of tyrosine hydroxylase and neuropeptide Y. Our findings demonstrate that both BAT and muscle-based NST are equally recruited during mild and severe cold adaptation and that loss of heat production from one thermogenic pathway leads to increased recruitment of the other, indicating a functional interplay between these two thermogenic processes.


Subject(s)
Acclimatization/physiology , Adipose Tissue, Brown/metabolism , Cold Temperature , Mitochondria, Muscle/metabolism , Muscle, Skeletal/metabolism , Thermogenesis/physiology , Animals , Mice , Mice, Knockout , Mitochondria, Muscle/genetics , Muscle Proteins/biosynthesis , Muscle Proteins/genetics , Proteolipids/biosynthesis , Proteolipids/genetics , Uncoupling Protein 1/biosynthesis , Uncoupling Protein 1/genetics , Up-Regulation/physiology
19.
J Endocrinol ; 235(1): 27-38, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28739822

ABSTRACT

Hypoxia-inducible lipid droplet-associated protein (HILPDA) has been shown to localize to lipid droplets in nutrient-responsive cell types such as hepatocytes and adipocytes. However, its role in the control of whole-body homeostasis is not known. We sought to measure cell-intrinsic and systemic stress responses in a mouse strain harboring whole-body Hilpda deficiency. We generated a genetically engineered mouse model of whole-body HILPDA deficiency by replacing the coding Hilpda exon with luciferase. We subjected the knockout animals to environmental stresses and measured whole-animal metabolic and behavioral parameters. Brown adipocyte precursors were isolated and differentiated in vitro to quantify the impact of HILPDA ablation in lipid storage and mobilization in these cells. HILPDA-knockout animals are viable and fertile, but show reduced ambulatory activity and oxygen consumption at regular housing conditions. Acclimatization at thermoneutral conditions abolished the phenotypic differences observed at 22°C. When fasted, HILPDA KO mice are unable to maintain body temperature and become hypothermic at 22°C, without apparent abnormalities in blood chemistry parameters or tissue triglyceride content. HILPDA expression was upregulated during adipocyte differentiation and activation in vitro; however, it was not required for lipid droplet formation in brown adipocytes. We conclude that HILPDA is necessary for efficient fuel utilization suggesting a homeostatic role for Hilpda in sub-optimal environments.


Subject(s)
Body Temperature Regulation , DNA-Binding Proteins/metabolism , Fasting/physiology , Adipocytes/metabolism , Animals , DNA-Binding Proteins/genetics , Female , Mice , Mice, Knockout , Stress, Physiological , Triglycerides/metabolism
20.
Genome Announc ; 5(28)2017 Jul 13.
Article in English | MEDLINE | ID: mdl-28705985

ABSTRACT

Pantoea latae strain AS1 was isolated from the rhizophere of a cycad, Zamia floridana, in central Florida, USA. Here, we report the de novo whole-genome sequence of this strain, which consists of a total of 83 contigs spanning 4,960,415 bp, with a G+C content of 59.6%, and comprising 4,527 predicted coding sequences.

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