30 results on '"Secco B"'
Search Results
2. Altered lipid metabolism impairs skeletal muscle force in young rats submitted to a short-term high-fat diet
- Author
-
Andrich, D. E., Ou, Y., Melbouci, L., Leduc-Gaudet, J. P., Auclair, N., Mercier, J., Secco, B., Tomaz, L. M., Gouspillou, G., Danialou, G., Comtois, A. S., St-Pierre, D. H., Andrich, D. E., Ou, Y., Melbouci, L., Leduc-Gaudet, J. P., Auclair, N., Mercier, J., Secco, B., Tomaz, L. M., Gouspillou, G., Danialou, G., Comtois, A. S., and St-Pierre, D. H.
- Abstract
Obesity and ensuing disorders are increasingly prevalent in young populations. Prolonged exposure to high-fat diets (HFD) and excessive lipid accumulation were recently suggested to impair skeletal muscle functions in rodents. We aimed to determine the effects of a short-term HFD on skeletal muscle function in young rats. Young male Wistar rats (100-125 g) were fed HFD or a regular chow diet (RCD) for 14 days. Specific force, resistance to fatigue and recovery were tested in extensor digitorum longus (EDL; glycolytic) and soleus (SOL; oxidative) muscles using an ex vivo muscle contractility system. Muscle fiber typing and insulin signaling were analyzed while intramyocellular lipid droplets (LD) were characterized. Expression of key markers of lipid metabolism was also measured. Weight gain was similar for both groups. Specific force was decreased in SOL, but not in EDL of HFD rats. Muscle resistance to fatigue and force recovery were not altered in response to the diets. Similarly, muscle fiber type distribution and insulin signaling were not influenced by HFD. On the other hand, percent area and average size of intramyocellular LDs were significantly increased in the SOL of HFD rats. These effects were consistent with the increased expression of several mediators of lipid metabolism in the SOL muscle. A short-term HFD impairs specific force and alters lipid metabolism in SOL, but not EDL muscles of young rats. This indicates the importance of clarifying the early mechanisms through which lipid metabolism affects skeletal muscle functions in response to obesogenic diets in young populations.
- Published
- 2018
3. Selection and hydroponic growth of potato cultivars for bioregenerative life support systems
- Author
-
UCL - SST/ELI/ELIA - Agronomy, Molders, K., Quinet, Muriel, Decat, J., Secco, B., Dulière, E., Pieters, S., van der Kooij, T., Lutts, Stanley, Van Der Straeten, D., UCL - SST/ELI/ELIA - Agronomy, Molders, K., Quinet, Muriel, Decat, J., Secco, B., Dulière, E., Pieters, S., van der Kooij, T., Lutts, Stanley, and Van Der Straeten, D.
- Abstract
As part of the ESA-funded MELiSSA program, Ghent University and the Université catholique de Louvain investigated the suitability, growth and development of four potato cultivars in hydroponic culture under controlled conditions with the aim to incorporate such cultivation system in an Environmental Control and Life Support System (ECLSS). Potato plants can fulfill three major functions in an ECLSS in space missions: (a) fixation of CO2 and production of O2, (b) production of tubers for human nutrition and (c) production of clean water after condensation of the water vapor released from the plants by transpiration. Four cultivars (Annabelle, Bintje, Desiree and Innovator) were selected and grown hydroponically in nutrient film technique (NFT) gullies in a growth chamber under controlled conditions. The plant growth parameters, tuber harvest parameters and results of tuber nutritional analysis of the four cultivars were compared. The four potato cultivars grew well and all produced tubers. The growth period lasted 127 days for all cultivars except for Desiree which needed 145 days. Annabelle (1.45 kg/m2) and Bintje (1.355 kg/m2) were the best performing of the four cultivars. They also produced two times more tubers than Desiree and Innovator. Innovator produced the biggest tubers (20.95 g/tuber) and Desiree the smallest (7.67 g/tuber). The size of Annabelle and Bintje potatoes were intermediate. Bintje plants produced the highest total biomass in term of DW. The highest non-edible biomass was produced by Desiree, which showed both the highest shoot and root DW. The manual length and width measurements were also used to predict the total tuber mass. The energy values of the tubers remained in the range of the 2010 USDA and Souci-Fachmann-Kraut food composition databases. The amount of Ca determined was slightly reduced compared to the USDA value, but close to the Souci-Fachmann-Kraut value. The concentration of Cu, Zn and P were high compared to both databases. Clear
- Published
- 2012
4. RASPBERRY BREEDING AND BIOTISATION FOR INCREASING PLANT STRESS TOLERANCE AND ANTIOXIDANT ACTIVITY
- Author
-
Gollotte, A., primary, Secco, B., additional, Mercy, L., additional, Lemoine, M.C., additional, Durand, P., additional, Prost, M., additional, and Gianinazzi, S., additional
- Published
- 2009
- Full Text
- View/download PDF
5. In-Depth Study of the Electronic Properties of NIR-Emissive κ3N Terpyridine Rhenium(I) Dicarbonyl Complexes
- Author
-
Thomas Auvray, Benedetta Del Secco, Nelsi Zaccheroni, Amélie Dubreuil, Garry S. Hanan, Auvray T., Del Secco B., Dubreuil A., Zaccheroni N., and Hanan G.S.
- Subjects
010405 organic chemistry ,Structure-properties relationship ,Rhenium complexe ,chemistry.chemical_element ,Triphenyl phosphines ,Rhenium ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,Coordination mode ,Polymer chemistry ,Cationic complexe ,Near infrared emitter ,Physical and Theoretical Chemistry ,Terpyridine ,Oxidation potential ,Electronic properties - Abstract
The structure-properties relationship in a series of carbonyl rhenium(I) complexes based on substituted terpyridine ligands of general formula [Re(κxN-Rtpy)(CO)yL]n+ is explored by both experimental and theoretical methods. In these compounds, the terpyridine ligands adopt both bidentate (κ2N) and terdentate (κ3N) coordination modes associated with three or two carbonyls, respectively. Conversion from the κ2N to the κ3N coordination mode leads to large changes in the absorption spectra and oxidation potentials due to destabilization of the HOMO level of each complex. The absorption profiles of the κ3N complexes cover the whole visible spectra with lower maxima around 700 nm, tailing out to 800 nm, while no emission is observed with Br- as the axial ligand L. When the axial ligand is modified from the native halide to pyridine or triphenylphosphine, the lowest absorption band is blue-shifted by 60 and 90 nm, respectively. These cationic complexes are near-infrared emitters with emission maxima between 840 and 950 nm for the pyridine compounds and 780-800 nm for the triphenylphosphine compounds.
- Published
- 2020
- Full Text
- View/download PDF
6. New lanthanide metalloligands and their use for the assembly of ln-ag bimetallic coordination frameworks: Stepwise modular synthesis, structural characterization, and optical properties
- Author
-
Luca Prodi, Nelsi Zaccheroni, Gianfranco Ciani, Massimo Sgarzi, Benedetta Del Secco, Pierluigi Mercandelli, Lucia Carlucci, Marco Visconti, Simona Maggini, Visconti M., Maggini S., Ciani G., Mercandelli P., Del Secco B., Prodi L., Sgarzi M., Zaccheroni N., and Carlucci L.
- Subjects
Lanthanide ,Materials science ,Supramolecular chemistry ,Network structure ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,MOFS ,Silver salts ,METAL-ORGANIC FRAMEWORKS ,DESIGN ,Lanthanum ,TOOL ,General Materials Science ,CRYSTAL-STRUCTURES ,Bimetallic strip ,Settore CHIM/03 - Chimica Generale e Inorganica ,010405 organic chemistry ,Cationic polymerization ,General Chemistry ,Condensed Matter Physics ,SERIES ,0104 chemical sciences ,Crystallography ,CENTERS ,chemistry ,LUMINESCENCE ,PD ,COMPLEXES - Abstract
Stepwise self-assembly processes using new lanthanide metalloligands (Ln-MLs) and silver salts have been successfully applied to isolate 4f-4d heterometallic coordination networks of four different structural types. In particular, the new lanthanide tetrakis-chelate complexes NEt4[Ln(L1)4] [HL1 = 1,3-bis(4'-cyanophenyl)-1,3-propanedione; Ln = Eu (1a), La (1b), Nd (1c), Tb (1d)] and NEt4[Ln(L2)4] (HL2 = 1,3-bis(4'-pyridyl)-1,3-propanedione; Ln = Eu (1e), Nd (1f)] have been synthesized, characterized, and reacted with different silver salts. The use of NEt4[Ln-(L1)4] allowed then to isolate and characterize i) neutral onedimensional ladder-like species of formula [Ln(L1)4Ag] [Ln = Eu (2a), La(2b), Nd(2c), Tb(2d)] and ii) their supramolecular isomers [Ln(L1)4Ag] [Ln = Eu (3a), La (3b), Nd (3c), Tb (3d)] showing a very unstable 2D network structure, iii) the cationic 2D species [Ln(L1)4Ag2]X [Ln = Eu, X = PF6-, CF3SO3-, ClO4- (4a-4c); Ln = Tb, Nd, La X = PF6 - (4d-4f)], and, only for lanthanum, iv) a fourth 2D species of formula [La(L1)4(H2O)Ag] (5) and SQL topology. Of the eight nitrile groups on the MLs potentially coordinating, only a partial number is used for networking with Ag(I), that is, only two in families 2 and 3 and four in family 4 and in network 5. Finally, the four structural types are rationalized in terms of a new "pincer-like" secondary building unit (SBU) consisting of a silver cation coordinating two central carbon atoms (γ carbon) of two different diketonate ligands on the same ML. Therefore, it is shown that compounds 5, 4, and 2-3 contain, respectively, none, one, or two of such pincer-like SBUs. The luminescence properties of the Ln-MLs and some of their polymeric species have been also investigated in solution and in the solid state.
- Published
- 2019
7. Bright Phosphorescence of All-Organic Chromophores Confined within Water-Soluble Silica Nanoparticles
- Author
-
Paola Ceroni, Luca Ravotto, Benedetta Del Secco, Myriam Roy, Enrico Rampazzo, Nelsi Zaccheroni, Luca Prodi, Marc Gingras, Marco Villa, Sergei A. Vinogradov, Villa M., Del Secco B., Ravotto L., Roy M., Rampazzo E., Zaccheroni N., Prodi L., Gingras M., Vinogradov S.A., and Ceroni P.
- Subjects
Nanoparticle ,nanoparticle, silica, AIE, sulfurated, phosphorescence, emission ,02 engineering and technology ,Chromophore ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Metal ,Silica nanoparticles ,chemistry.chemical_compound ,General Energy ,Water soluble ,chemistry ,visual_art ,visual_art.visual_art_medium ,Molecule ,Physical and Theoretical Chemistry ,0210 nano-technology ,Benzene ,Phosphorescence - Abstract
Room temperature phosphorescence is usually a prerogative of metal complexes. Molecules with a hexakis(phenylthio)benzene core constitute a rare example of all-organic chromophores with phosphorescence induced by environmental rigidification. Here we report covalent encapsulation of functionalized persulfurated benzene chromophores into silica nanoparticles as a method of rigidification for induction of phosphorescence. The developed nanoparticles display bright phosphorescence at ambient temperatures and possess high colloidal stability in water. The method permits incorporation of a large number of chromophores (ca. 40) per nanoparticle while preserving their emissivity. The luminescence of the nanoparticles is sensitive to quenching by molecular oxygen in the physiological oxygen range, potentially making them suitable as probes for phosphorescence lifetime imaging of oxygen in biological systems.
- Published
- 2019
8. Optimized synthesis of luminescent silica nanoparticles by a direct micelle-assisted method
- Author
-
Luca Prodi, Enrico Rampazzo, Damiano Genovese, Nelsi Zaccheroni, Benedetta Del Secco, Tatiana V. Esipova, Luca Ravotto, Sergei A. Vinogradov, Del Secco B., Ravotto L., Esipova T.V., Vinogradov S.A., Genovese D., Zaccheroni N., Rampazzo E., and Prodi L.
- Subjects
Materials science ,Dopant ,Doping ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Poloxamer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Micelle ,Article ,0104 chemical sciences ,Nanomaterials ,Nanoparticles, Phosphorescence, Chemosensor, Luminescence, Sensing ,Surface modification ,Physical and Theoretical Chemistry ,0210 nano-technology ,Phosphorescence - Abstract
Silica nanoparticles (NPs) are versatile nanomaterials, which are safe with respect to biomedical applications, and therefore are highly investigated. The advantages of NPs include their ease of preparation, inexpensive starting materials and the possibility of functionalization or loading with various doping agents. However, the solubility of the doping agent(s) imposes constraints on the choice of the reaction system and hence limits the range of molecules that can be included in the interior of NPs. To overcome this problem, herein, we improved the current state of the art synthetic strategy based on Pluronic F127 by enabling the synthesis in the presence of large amounts of organic solvents. The new method enables the preparation of nanoparticles doped with large amounts of water-insoluble doping agents. To illustrate the applicability of the technology, we successfully incorporated a range of phosphorescent metalloporphyrins into the interior of NPs. The resulting phosphorescent nanoparticles may exhibit potential for biological oxygen sensing.
- Published
- 2019
9. Nanosized titanium dioxide particle emission potential from a commercial indoor air purifier photocatalytic surface: A case study.
- Author
-
Koivisto AJ, Trabucco S, Ravegnani F, Calzolari F, Nicosia A, Del Secco B, Altin M, Morabito E, Blosi M, Costa A, and Belosi F
- Abstract
Background: Photocatalytic air purifiers based on nano-titanium dioxide (TiO
2 ) visible light activation provide an efficient solution for removing and degrading contaminants in air. The potential detachment of TiO2 particles from the air purifier to indoor air could cause a safety concern. A TiO2 release potential was measured for one commercially available photocatalytic air purifier "Gearbox Wivactive" to ensure a successful implementation of the photocatalytic air purifying technology. Methods: In this study, the TiO2 release was studied under laboratory-simulated conditions from a Gearbox Wivactive consisting of ceramic honeycombs coated with photocatalytic nitrogen doped TiO2 particles. The TiO2 particle release factor was measured in scalable units according to the photoactive surface area and volume flow (TiO2 -ng/m2 ×m3 ). The impact of Gearbox Wivactive on indoor concentration level under reasonable worst-case conditions was predicted by using the release factor and a well-mixed indoor aerosol model. Results: The instrumentation and experimental setup was not sufficiently sensitive to quantify the emissions from the photoactive surfaces. The upper limit for TiO2 mass release was <185×10-3 TiO2 -ng/m2 ×m3 . Under realistic conditions the TiO2 concentration level in a 20 m3 room ventilated at rate of 0.5 1/h and containing two Gearbox Wivactive units resulted <20×10-3 TiO2 -ng/m3 . Conclusions: The release potential was quantified for a photocatalytic surface in generalized units that can be used to calculate the emission potential for different photocatalytic surfaces used in various operational conditions. This study shows that the TiO2 nanoparticle release potential was low in this case and the release does not cause relevant exposure as compared to proposed occupational exposure limit values for nanosized TiO2 . The TiO2 release risk was adequately controlled under reasonable worst-case operational conditions., Competing Interests: Competing interests: AJK works as an independent consultant in Air Pollution Management (APM). MA is employed by Witek srl., (Copyright: © 2022 Koivisto AJ et al.)- Published
- 2022
- Full Text
- View/download PDF
10. Loss of Human Beta Cell Identity in a Reconstructed Omental Stromal Cell Environment.
- Author
-
Secco B, Saitoski K, Drareni K, Soprani A, Pechberty S, Rachdi L, Venteclef N, and Scharfmann R
- Subjects
- Cell Line, Humans, Insulin metabolism, Stromal Cells metabolism, Diabetes Mellitus, Type 2 metabolism, Insulin-Secreting Cells metabolism
- Abstract
In human type 2 diabetes, adipose tissue plays an important role in disturbing glucose homeostasis by secreting factors that affect the function of cells and tissues throughout the body, including insulin-producing pancreatic beta cells. We aimed here at studying the paracrine effect of stromal cells isolated from subcutaneous and omental adipose tissue on human beta cells. We developed an in vitro model wherein the functional human beta cell line EndoC-βH1 was treated with conditioned media from human adipose tissues. By using RNA-sequencing and western blotting, we determined that a conditioned medium derived from omental stromal cells stimulates several pathways, such as STAT, SMAD and RELA, in EndoC-βH1 cells. We also observed that upon treatment, the expression of beta cell markers decreased while dedifferentiation markers increased. Loss-of-function experiments that efficiently blocked specific signaling pathways did not reverse dedifferentiation, suggesting the implication of more than one pathway in this regulatory process. Taken together, we demonstrate that soluble factors derived from stromal cells isolated from human omental adipose tissue signal human beta cells and modulate their identity.
- Published
- 2022
- Full Text
- View/download PDF
11. Assembling anisotropic colloids using curvature-mediated lipid sorting.
- Author
-
Kumar M, Singh A, Del Secco B, Baranov MV, van den Bogaart G, Sacanna S, and Thutupalli S
- Subjects
- Anisotropy, Protein Transport, Colloids chemistry, Lipid Bilayers chemistry
- Abstract
The use of colloid supported lipid bilayers (CSLBs) for assembling colloidal structures has been of recent interest. Here, we use multi-component lipid bilayer membranes formed around anisotropic colloids and show that the curvature anisotropy of the colloids drives a sorting of the lipids in the membrane along the colloids. We then exploit this curvature-sensitive lipid sorting to create "shape-anisotropic patchy colloids" - specifically, we use colloids with six rods sticking out of a central cubic core, "hexapods", for this purpose and demonstrate that membrane patches self-assemble at the tip of each of the six colloidal rods. The membrane patches are rendered sticky using biotinylated lipids in complement with a biotin-binding streptavidin protein. Finally, using these "shape-anisotropic patchy colloids", we demonstrate the directed assembly of colloidal links, paving the way for the creation of heterogeneous and flexible colloidal structures.
- Published
- 2022
- Full Text
- View/download PDF
12. Quantifying Emission Factors and Setting Conditions of Use According to ECHA Chapter R.14 for a Spray Process Designed for Nanocoatings-A Case Study.
- Author
-
Koivisto AJ, Del Secco B, Trabucco S, Nicosia A, Ravegnani F, Altin M, Cabellos J, Furxhi I, Blosi M, Costa A, Lopez de Ipiña J, and Belosi F
- Abstract
Spray coatings' emissions impact to the environmental and occupational exposure were studied in a pilot-plant. Concentrations were measured inside the spray chamber and at the work room in Near-Field (NF) and Far-Field (FF) and mass flows were analyzed using a mechanistic model. The coating was performed in a ventilated chamber by spraying titanium dioxide doped with nitrogen (TiO
2 N) and silver capped by hydroxyethylcellulose (Ag-HEC) nanoparticles (NPs). Process emission rates to workplace, air, and outdoor air were characterized according to process parameters, which were used to assess emission factors. Full-scale production exposure potential was estimated under reasonable worst-case (RWC) conditions. The measured TiO2 -N and Ag-HEC concentrations were 40.9 TiO2 -μg/m3 and 0.4 Ag-μg/m3 at NF (total fraction). Under simulated RWC conditions with precautionary emission rate estimates, the worker's 95th percentile 8-h exposure was ≤171 TiO2 and ≤1.9 Ag-μg/m3 (total fraction). Environmental emissions via local ventilation (LEV) exhaust were ca. 35 and 140 mg-NP/g-NP, for TiO2 -N and Ag-HEC, respectively. Under current situation, the exposure was adequately controlled. However, under full scale production with continuous process workers exposure should be evaluated with personal sampling if recommended occupational exposure levels for nanosized TiO2 and Ag are followed for risk management.- Published
- 2022
- Full Text
- View/download PDF
13. Particles Emission from an Industrial Spray Coating Process Using Nano-Materials.
- Author
-
Del Secco B, Trabucco S, Ravegnani F, Koivisto AJ, Zanoni I, Blosi M, Ortelli S, Altin M, Bartolini G, Costa AL, and Belosi F
- Abstract
Industrial spray coating processes are known to produce excellent coatings on large surfaces and are thus often used for in-line production. However, they could be one of the most critical sources of worker exposure to ultrafine particles (UFPs). A monitoring campaign at the Witek s.r.l. (Florence, Italy) was deployed to characterize the release of TiO
2 NPs doped with nitrogen (TiO2 -N) and Ag capped with hydroxyethyl cellulose (AgHEC) during automatic industrial spray-coating of polymethyl methacrylate (PMMA) and polyester. Aerosol particles were characterized inside the spray chamber at near field (NF) and far field (FF) locations using on-line and off-line instruments. Results showed that TiO2 -N suspension produced higher particle number concentrations than AgHEC in the size range 0.3-1 µm (on average 1.9 102 p/cm3 and 2.5 101 p/cm3 , respectively) after background removing. At FF, especially at worst case scenario (4 nozzles, 800 mL/min flow rate) for TiO2 -N, the spray spikes were correlated with NF, with an observed time lag of 1 minute corresponding to a diffusion speed of 0.1 m/s. The averaged ratio between particles mass concentrations in the NF position and inside the spray chamber was 1.7% and 1.5% for TiO2 -N and for AgHEC suspensions, respectively. The released particles' number concentration of TiO2 -N in the size particles range 0.3-1 µm was comparable for both PMMA and polyester substrates, about 1.5 and 1.6 102 p/cm3 . In the size range 0.01-30 µm, the aerosol number concentration at NF for both suspensions was lower than the nano reference values (NRVs) of 16·103 p/cm-3 .- Published
- 2022
- Full Text
- View/download PDF
14. Monitoring and Optimisation of Ag Nanoparticle Spray-Coating on Textiles.
- Author
-
Trabucco S, Ortelli S, Del Secco B, Zanoni I, Belosi F, Ravegnani F, Nicosia A, Blosi M, and Costa AL
- Abstract
An automatic lab-scaled spray-coating machine was used to deposit Ag nanoparticles (AgNPs) on textile to create antibacterial fabric. The spray process was monitored for the dual purpose of (1) optimizing the process by maximizing silver deposition and minimizing fluid waste, thereby reducing suspension consumption and (2) assessing AgNPs release. Monitoring measurements were carried out at two locations: inside and outside the spray chamber (far field). We calculated the deposition efficiency (E), finding it to be enhanced by increasing the spray pressure from 1 to 1.5 bar, but to be lowered when the number of operating sprays was increased, demonstrating the multiple spray system to be less efficient than a single spray. Far-field AgNPs emission showed a particle concentration increase of less than 10% as compared to the background level. This finding suggests that under our experimental conditions, our spray-coating process is not a critical source of worker exposure.
- Published
- 2021
- Full Text
- View/download PDF
15. Data Shepherding in Nanotechnology. The Exposure Field Campaign Template.
- Author
-
Furxhi I, Koivisto AJ, Murphy F, Trabucco S, Del Secco B, and Arvanitis A
- Abstract
In this paper, we demonstrate the realization process of a pragmatic approach on developing a template for capturing field monitoring data in nanomanufacturing processes. The template serves the fundamental principles which make data scientifically Findable, Accessible, Interoperable and Reusable (FAIR principles), as well as encouraging individuals to reuse it. In our case, the data shepherds' (the guider of data) template creation workflow consists of the following steps: (1) Identify relevant stakeholders, (2) Distribute questionnaires to capture a general description of the data to be generated, (3) Understand the needs and requirements of each stakeholder, (4) Interactive simple communication with the stakeholders for variables/descriptors selection, and (5) Design of the template and annotation of descriptors. We provide an annotated template for capturing exposure field campaign monitoring data, and increase their interoperability, while comparing it with existing templates. This paper enables the data creators of exposure field campaign data to store data in a FAIR way and helps the scientific community, such as data shepherds, by avoiding extensive steps for template creation and by utilizing the pragmatic structure and/or the template proposed herein, in the case of a nanotechnology project (Anticipating Safety Issues at the Design of Nano Product Development, ASINA).
- Published
- 2021
- Full Text
- View/download PDF
16. Control of adipogenic commitment by a STAT3-VSTM2A axis.
- Author
-
Al Dow M, Silveira MAD, Poliquin A, Tribouillard L, Fournier É, Trébaol E, Secco B, Villot R, Tremblay F, Bilodeau S, and Laplante M
- Subjects
- 3T3-L1 Cells, Adipose Tissue, White metabolism, Animals, Cell Differentiation genetics, Gene Expression Regulation, Male, Membrane Proteins genetics, Mice, Mice, Inbred C57BL, STAT3 Transcription Factor genetics, Signal Transduction genetics, Adipocytes physiology, Adipogenesis genetics, Membrane Proteins physiology, STAT3 Transcription Factor physiology
- Abstract
White adipose tissue (WAT) is a dynamic organ that plays crucial roles in controlling metabolic homeostasis. During development and periods of energy excess, adipose progenitors are recruited and differentiate into adipocytes to promote lipid storage capability. The identity of adipose progenitors and the signals that promote their recruitment are still incompletely characterized. We have recently identified V-set and transmembrane domain-containing protein 2A (VSTM2A) as a novel protein enriched in preadipocytes that amplifies adipogenic commitment. Despite the emerging role of VSTM2A in promoting adipogenesis, the molecular mechanisms regulating Vstm2a expression in preadipocytes are still unknown. To define the molecular mechanisms controlling Vstm2a expression, we have treated preadipocytes with an array of compounds capable of modulating established regulators of adipogenesis. Here, we report that Vstm2a expression is positively regulated by PI3K/mTOR and cAMP-dependent signaling pathways and repressed by the MAPK pathway and the glucocorticoid receptor. By integrating the impact of all the molecules tested, we identified signal transducer and activator of transcription 3 (STAT3) as a novel downstream transcription factor affecting Vstm2a expression. We show that activation of STAT3 increased Vstm2a expression, whereas its inhibition repressed this process. In mice, we found that STAT3 phosphorylation is elevated in the early phases of WAT development, an effect that strongly associates with Vstm2a expression. Our findings identify STAT3 as a key transcription factor regulating Vstm2a expression in preadipocytes. NEW & NOTEWORTHY cAMP-dependent and PI3K-mTOR signaling pathways promote the expression of Vstm2a . STAT3 is a key transcription factor that controls Vstm2a expression in preadipocytes. STAT3 is activated in the early phases of WAT development, an effect that strongly associates with Vstm2a expression.
- Published
- 2021
- Full Text
- View/download PDF
17. Optimized synthesis of luminescent silica nanoparticles by a direct micelle-assisted method.
- Author
-
Del Secco B, Ravotto L, Esipova TV, Vinogradov SA, Genovese D, Zaccheroni N, Rampazzo E, and Prodi L
- Abstract
Silica nanoparticles (NPs) are versatile nanomaterials, which are safe with respect to biomedical applications, and therefore are highly investigated. The advantages of NPs include their ease of preparation, inexpensive starting materials and the possibility of functionalization or loading with various doping agents. However, the solubility of the doping agent(s) imposes constraints on the choice of the reaction system and hence limits the range of molecules that can be included in the interior of NPs. To overcome this problem, herein, we improved the current state of the art synthetic strategy based on Pluronic F127 by enabling the synthesis in the presence of large amounts of organic solvents. The new method enables the preparation of nanoparticles doped with large amounts of water-insoluble doping agents. To illustrate the applicability of the technology, we successfully incorporated a range of phosphorescent metalloporphyrins into the interior of NPs. The resulting phosphorescent nanoparticles may exhibit potential for biological oxygen sensing.
- Published
- 2019
- Full Text
- View/download PDF
18. PGC1A regulates the IRS1:IRS2 ratio during fasting to influence hepatic metabolism downstream of insulin.
- Author
-
Besse-Patin A, Jeromson S, Levesque-Damphousse P, Secco B, Laplante M, and Estall JL
- Subjects
- Animals, Cyclic AMP Response Element-Binding Protein metabolism, Diabetes Mellitus, Type 2 metabolism, Female, Gene Expression Regulation, Glucagon metabolism, Gluconeogenesis, Glucose metabolism, Hepatocytes metabolism, Homeostasis, Humans, Insulin Receptor Substrate Proteins genetics, Insulin Resistance, Liver Diseases metabolism, Male, Mice, Models, Animal, Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha genetics, Proto-Oncogene Proteins c-akt metabolism, Signal Transduction, Fasting, Insulin metabolism, Insulin Receptor Substrate Proteins metabolism, Liver metabolism, Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha metabolism
- Abstract
Precise modulation of hepatic glucose metabolism is crucial during the fasting and feeding cycle and is controlled by the actions of circulating insulin and glucagon. The insulin-signaling pathway requires insulin receptor substrate 1 (IRS1) and IRS2, which are found to be dysregulated in diabetes and obesity. The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1A) is a fasting-induced transcriptional coactivator. In nonalcoholic fatty liver disease and in patients with type 2 diabetes, low hepatic PGC1A levels are associated with insulin resistance. However, how PGC1A activity impacts the hepatic insulin-signaling pathway is still unclear. We used gain- and loss-of-function models in mouse primary hepatocytes and measured hepatocyte insulin response by gene and protein expression and ex vivo glucose production. We found that the PGC1A level determines the relative ratio of IRS1 and IRS2 in hepatocytes, impacting insulin receptor signaling via protein kinase B/AKT (AKT). PGC1A drove the expression of IRS2 downstream of glucagon signaling while simultaneously reducing IRS1 expression. We illustrate that glucagon- or PGC1A-induced IRS2 expression was dependent on cAMP Response Element Binding Protein activity and that this was essential for suppression of hepatocyte gluconeogenesis in response to insulin in vitro. We also show that increased hepatic PGC1A improves glucose homeostasis in vivo, revealing a counterregulatory role for PGC1A in repressing uncontrolled glucose production in response to insulin signaling. These data highlight a mechanism by which PGC1A plays dual roles in the control of gluconeogenesis during the fasting-to-fed transition through regulated balance between IRS1 and IRS2 expression., Competing Interests: The authors declare no conflict of interest., (Copyright © 2019 the Author(s). Published by PNAS.)
- Published
- 2019
- Full Text
- View/download PDF
19. Engineered Nanostructured Materials for Ofloxacin Delivery.
- Author
-
Nuti S, Fernández-Lodeiro J, Del Secco B, Rampazzo E, Rodríguez-González B, Capelo JL, Silva V, Igrejas G, Poeta P, Torres C, Zaccheroni N, Prodi L, Oliveira E, and Lodeiro C
- Abstract
Antibiotic resistance is emerging as a growing worldwide problem and finding solutions to this issue is becoming a new challenge for scientists. As the development of new drugs slowed down, advances in nanotechnology offer great opportunities, with the possibility of designing new systems for carrying, delivery and administration of drugs already in use. Engineered combinations of the synthetic, broad-spectrum antibiotic ofloxacin, rarely studied in this field, with different types of silver, mesoporous silica-based and Pluronic/silica-based nanoparticles have been explored. The nanocarriers as silver core@silica mesoporous (AgMSNPs) and dye-doped silica nanoparticles functionalized with ofloxacin were synthesized and their antibacterial properties studied against S. aureus and E. coli . The best antibacterial results were obtained for the AgMSNPs nanosystem@ofloxacin for the strain S. aureus ATCC 25923, with MIC and MBC values of 5 and 25 μg/mL, proving the efficacy and synergetic effect of the antibiotic and the Ag core of the nanoparticles.
- Published
- 2018
- Full Text
- View/download PDF
20. Altered Lipid Metabolism Impairs Skeletal Muscle Force in Young Rats Submitted to a Short-Term High-Fat Diet.
- Author
-
Andrich DE, Ou Y, Melbouci L, Leduc-Gaudet JP, Auclair N, Mercier J, Secco B, Tomaz LM, Gouspillou G, Danialou G, Comtois AS, and St-Pierre DH
- Abstract
Obesity and ensuing disorders are increasingly prevalent in young populations. Prolonged exposure to high-fat diets (HFD) and excessive lipid accumulation were recently suggested to impair skeletal muscle functions in rodents. We aimed to determine the effects of a short-term HFD on skeletal muscle function in young rats. Young male Wistar rats (100-125 g) were fed HFD or a regular chow diet (RCD) for 14 days. Specific force, resistance to fatigue and recovery were tested in extensor digitorum longus (EDL; glycolytic) and soleus (SOL; oxidative) muscles using an ex vivo muscle contractility system. Muscle fiber typing and insulin signaling were analyzed while intramyocellular lipid droplets (LD) were characterized. Expression of key markers of lipid metabolism was also measured. Weight gain was similar for both groups. Specific force was decreased in SOL, but not in EDL of HFD rats. Muscle resistance to fatigue and force recovery were not altered in response to the diets. Similarly, muscle fiber type distribution and insulin signaling were not influenced by HFD. On the other hand, percent area and average size of intramyocellular LDs were significantly increased in the SOL of HFD rats. These effects were consistent with the increased expression of several mediators of lipid metabolism in the SOL muscle. A short-term HFD impairs specific force and alters lipid metabolism in SOL, but not EDL muscles of young rats. This indicates the importance of clarifying the early mechanisms through which lipid metabolism affects skeletal muscle functions in response to obesogenic diets in young populations.
- Published
- 2018
- Full Text
- View/download PDF
21. The Role of Onium Salts in the Pro-Oxidant Effect of Gold Nanoparticles in Lipophilic Environments.
- Author
-
Baschieri A, Del Secco B, Zaccheroni N, Valgimigli L, and Amorati R
- Abstract
Metal nanoparticles are reported to be toxic due to the generation of free radicals at their surface. Relatively inert thiol-capped gold nanoparticles (AuNPs) have been reported to induce radical formation in the presence of hydroperoxides, which would conflict with their potential use as inert scaffolds for the design of novel nano-antioxidants. With the aim of clarifying this aspect, we investigated the pro-oxidant activity of dodecanethiol-capped AuNPs (∼5 nm diameter), prepared through the Brust-Schiffrin synthesis, by oxygen-uptake kinetic studies. The pro-oxidant activity was found to be proportional to the impurities of the transfer agent tetraoctylammonium bromide (TOAB) left from the synthesis and decreased on repeated washing of the nanoparticles. Under identical settings similar batches of AuNP (∼9 nm diameter) prepared through the Ulman method without onium salts showed no pro-oxidant behavior. The alternative onium phase-transfer agents Oct
4 NBF4 (Oct=octyl), Hex4 NBF4 (Hex=hexyl), and Hex4 NPF6 were comparatively investigated and showed lower pro-oxidant activity depending on the counterion (Br- >PF6 - >BF4 - )., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2018
- Full Text
- View/download PDF
22. Lung cancer susceptibility genetic variants modulate HOXB2 expression in the lung.
- Author
-
Clemenceau A, Boucherat O, Landry-Truchon K, Lamontagne M, Biardel S, Joubert P, Gobeil S, Secco B, Laplante M, Morissette M, Obeidat M, Timens W, Jeannotte L, and Bossé Y
- Subjects
- Aged, Female, Gene Expression Regulation, Neoplastic, Genes, Homeobox, Homeodomain Proteins metabolism, Humans, Lung Neoplasms metabolism, Male, Middle Aged, Quantitative Trait Loci, Transcription Factors metabolism, Genetic Predisposition to Disease, Homeodomain Proteins genetics, Lung metabolism, Lung Neoplasms genetics, Polymorphism, Single Nucleotide, Transcription Factors genetics
- Abstract
The HOX genes are transcription factors that are expressed in coordinated spatiotemporal patterns to ensure normal development. Ectopic expression may instead lead to the development and progression of tumors. Genetic polymorphisms in the regions of four HOX gene clusters were tested for association with lung cancer in 420 cases and 3,151 controls. The effect of these variants on lung gene expression (expression quantitative trait loci, eQTL) was tested in a discovery set of 409 non-tumor lung samples and validated in two lung eQTL replication sets (n = 287 and 342). The expression levels of HOXB2 were evaluated at the mRNA and protein levels by quantitative real-time PCR and immunohistochemistry in paired tumor and non-tumor lung tissue samples. The most significant SNP associated with lung cancer in the HOXB cluster was rs10853100 located upstream of the HOXB cluster. HOXB2 was the top eQTL-regulated gene with several polymorphisms associated with its mRNA expression levels in lung tissue. This includes the lung cancer SNP rs10853100 that was significantly associated with HOXB2 expression (P=3.39E-7). In the lung eQTL discovery and replication sets, the lung cancer risk allele (T) for rs10853100 was associated with lower HOXB2 expression levels. In paired normal-tumor samples, HOXB2 mRNA and protein levels were significantly reduced in tumors when compared to non-tumor lung tissues. Genetic variants in the HOXB cluster may confer susceptibility to lung cancer by modulating the expression of HOXB2 in the lung.
- Published
- 2018
- Full Text
- View/download PDF
23. Form Matters: Stable Helical Foldamers Preferentially Target Human Monocytes and Granulocytes.
- Author
-
Del Secco B, Malachin G, Milli L, Zanna N, Papini E, Cornia A, Tavano R, and Tomasini C
- Subjects
- Amino Acids chemistry, Biocompatible Materials chemical synthesis, Biocompatible Materials chemistry, Cell Survival drug effects, Cells, Cultured, Circular Dichroism, Crystallography, X-Ray, Granulocytes cytology, Granulocytes metabolism, HeLa Cells, Humans, Microscopy, Confocal, Molecular Conformation, Monocytes cytology, Monocytes metabolism, Peptoids chemical synthesis, Peptoids chemistry, Biocompatible Materials pharmacology, Granulocytes drug effects, Monocytes drug effects, Peptoids pharmacology
- Abstract
Some hybrid foldamers of various length, all containing the (4R,5S)-4-carboxy-5-methyloxazolidin-2-one (d-Oxd) moiety alternating with an l-amino acid (l-Val, l-Lys, or l-Ala), were prepared in order to study their preferred conformations and to evaluate their biological activity. Surprisingly, only the longer oligomers containing l-Ala fold into well-established helices, whereas all the other oligomers give partially unfolded turn structures. Nevertheless, they all show good biocompatibility, with no detrimental effects up to 64 μm. After equipping some selected foldamers with the fluorescent tag rhodamine B, a quantitative analysis was performed by dose- and time-response fluorescence-activated cell sorting (FACS) assays with human HeLa cells and primary blood lymphocytes, granulocytes, and monocytes. Among the cell types analyzed, the oligomers associated with monocytes and granulocytes with greatest efficacy, still visible after 24 h incubation. This effect is even more pronounced for foldamers that are able to form stable helices., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2017
- Full Text
- View/download PDF
24. Loss of hepatic DEPTOR alters the metabolic transition to fasting.
- Author
-
Caron A, Mouchiroud M, Gautier N, Labbé SM, Villot R, Turcotte L, Secco B, Lamoureux G, Shum M, Gélinas Y, Marette A, Richard D, Sabatini DM, and Laplante M
- Subjects
- Animals, Cytochromes c metabolism, Glycogen metabolism, Intracellular Signaling Peptides and Proteins metabolism, Male, Mechanistic Target of Rapamycin Complex 1 metabolism, Mice, Mice, Inbred C57BL, Blood Glucose metabolism, Fasting metabolism, Intracellular Signaling Peptides and Proteins genetics, Liver metabolism
- Abstract
Objective: The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that functions into distinct protein complexes (mTORC1 and mTORC2) that regulates growth and metabolism. DEP-domain containing mTOR-interacting protein (DEPTOR) is part of these complexes and is known to reduce their activity. Whether DEPTOR loss affects metabolism and organismal growth in vivo has never been tested., Methods: We have generated a conditional transgenic mouse allowing the tissue-specific deletion of DEPTOR. This model was crossed with CMV-cre mice or Albumin-cre mice to generate either whole-body or liver-specific DEPTOR knockout (KO) mice., Results: Whole-body DEPTOR KO mice are viable, fertile, normal in size, and do not display any gross physical and metabolic abnormalities. To circumvent possible compensatory mechanisms linked to the early and systemic loss of DEPTOR, we have deleted DEPTOR specifically in the liver, a tissue in which DEPTOR protein is expressed and affected in response to mTOR activation. Liver-specific DEPTOR null mice showed a reduction in circulating glucose upon fasting versus control mice. This effect was not associated with change in hepatic gluconeogenesis potential but was linked to a sustained reduction in circulating glucose during insulin tolerance tests. In addition to the reduction in glycemia, liver-specific DEPTOR KO mice had reduced hepatic glycogen content when fasted. We showed that loss of DEPTOR cell-autonomously increased oxidative metabolism in hepatocytes, an effect associated with increased cytochrome c expression but independent of changes in mitochondrial content or in the expression of genes controlling oxidative metabolism. We found that liver-specific DEPTOR KO mice showed sustained mTORC1 activation upon fasting, and that acute treatment with rapamycin was sufficient to normalize glycemia in these mice., Conclusion: We propose a model in which hepatic DEPTOR accelerates the inhibition of mTORC1 during the transition to fasting to adjust metabolism to the nutritional status.
- Published
- 2017
- Full Text
- View/download PDF
25. Amplification of Adipogenic Commitment by VSTM2A.
- Author
-
Secco B, Camiré É, Brière MA, Caron A, Billong A, Gélinas Y, Lemay AM, Tharp KM, Lee PL, Gobeil S, Guimond JV, Patey N, Guertin DA, Stahl A, Haddad É, Marsolais D, Bossé Y, Birsoy K, and Laplante M
- Subjects
- 3T3-L1 Cells, Adipocytes metabolism, Adipose Tissue, White blood supply, Adipose Tissue, White cytology, Animals, Biomarkers metabolism, Bone Morphogenetic Proteins metabolism, Cell Differentiation, Gene Knockdown Techniques, Humans, Male, Mesenchymal Stem Cells cytology, Mesenchymal Stem Cells metabolism, Mice, Mice, Inbred C57BL, Middle Aged, NIH 3T3 Cells, Neovascularization, Physiologic, PPAR gamma metabolism, Signal Transduction, Adipogenesis, Cell Lineage, Membrane Proteins metabolism, Receptors, Immunologic metabolism
- Abstract
Despite progress in our comprehension of the mechanisms regulating adipose tissue development, the nature of the factors that functionally characterize adipose precursors is still elusive. Defining the early steps regulating adipocyte development is needed for the generation of tools to control adipose tissue size and function. Here, we report the discovery of V-set and transmembrane domain containing 2A (VSTM2A) as a protein expressed and secreted by committed preadipocytes. VSTM2A expression is elevated in the early phases of adipogenesis in vitro and adipose tissue development in vivo. We show that VSTM2A-producing cells associate with the vasculature and express the common surface markers of adipocyte progenitors. Overexpression of VSTM2A induces adipogenesis, whereas its depletion impairs this process. VSTM2A controls preadipocyte determination at least in part by modulating BMP signaling and PPARγ2 activation. We propose a model in which VSTM2A is produced to preserve and amplify the adipogenic capability of adipose precursors., (Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
26. mTORC1 is Required for Brown Adipose Tissue Recruitment and Metabolic Adaptation to Cold.
- Author
-
Labbé SM, Mouchiroud M, Caron A, Secco B, Freinkman E, Lamoureux G, Gélinas Y, Lecomte R, Bossé Y, Chimin P, Festuccia WT, Richard D, and Laplante M
- Subjects
- Adipocytes, Brown cytology, Adipose Tissue, Brown cytology, Animals, Male, Mechanistic Target of Rapamycin Complex 1 genetics, Mice, Mice, Transgenic, Mitochondria genetics, Oxygen Consumption physiology, Acclimatization physiology, Adipocytes, Brown metabolism, Adipose Tissue, Brown metabolism, Cold Temperature, Mechanistic Target of Rapamycin Complex 1 metabolism, Mitochondria metabolism
- Abstract
In response to cold, brown adipose tissue (BAT) increases its metabolic rate and expands its mass to produce heat required for survival, a process known as BAT recruitment. The mechanistic target of rapamycin complex 1 (mTORC1) controls metabolism, cell growth and proliferation, but its role in regulating BAT recruitment in response to chronic cold stimulation is unknown. Here, we show that cold activates mTORC1 in BAT, an effect that depends on the sympathetic nervous system. Adipocyte-specific mTORC1 loss in mice completely blocks cold-induced BAT expansion and severely impairs mitochondrial biogenesis. Accordingly, mTORC1 loss reduces oxygen consumption and causes a severe defect in BAT oxidative metabolism upon cold exposure. Using in vivo metabolic imaging, metabolomics and transcriptomics, we show that mTORC1 deletion impairs glucose and lipid oxidation, an effect linked to a defect in tricarboxylic acid (TCA) cycle activity. These analyses also reveal a severe defect in nucleotide synthesis in the absence of mTORC1. Overall, these findings demonstrate an essential role for mTORC1 in the regulation of BAT recruitment and metabolism in response to cold.
- Published
- 2016
- Full Text
- View/download PDF
27. The oncometabolite 2-hydroxyglutarate activates the mTOR signalling pathway.
- Author
-
Carbonneau M, M Gagné L, Lalonde ME, Germain MA, Motorina A, Guiot MC, Secco B, Vincent EE, Tumber A, Hulea L, Bergeman J, Oppermann U, Jones RG, Laplante M, Topisirovic I, Petrecca K, Huot MÉ, and Mallette FA
- Subjects
- Astrocytes metabolism, Citric Acid Cycle, Glioma genetics, HEK293 Cells, HeLa Cells, Humans, Intracellular Signaling Peptides and Proteins metabolism, Mechanistic Target of Rapamycin Complex 1 metabolism, Mechanistic Target of Rapamycin Complex 2 metabolism, PTEN Phosphohydrolase genetics, Ubiquitination, beta-Transducin Repeat-Containing Proteins metabolism, Glutarates metabolism, Isocitrate Dehydrogenase genetics, Jumonji Domain-Containing Histone Demethylases metabolism, TOR Serine-Threonine Kinases metabolism
- Abstract
The identification of cancer-associated mutations in the tricarboxylic acid (TCA) cycle enzymes isocitrate dehydrogenases 1 and 2 (IDH1/2) highlights the prevailing notion that aberrant metabolic function can contribute to carcinogenesis. IDH1/2 normally catalyse the oxidative decarboxylation of isocitrate into α-ketoglutarate (αKG). In gliomas and acute myeloid leukaemias, IDH1/2 mutations confer gain-of-function leading to production of the oncometabolite R-2-hydroxyglutarate (2HG) from αKG. Here we show that generation of 2HG by mutated IDH1/2 leads to the activation of mTOR by inhibiting KDM4A, an αKG-dependent enzyme of the Jumonji family of lysine demethylases. Furthermore, KDM4A associates with the DEP domain-containing mTOR-interacting protein (DEPTOR), a negative regulator of mTORC1/2. Depletion of KDM4A decreases DEPTOR protein stability. Our results provide an additional molecular mechanism for the oncogenic activity of mutant IDH1/2 by revealing an unprecedented link between TCA cycle defects and positive modulation of mTOR function downstream of the canonical PI3K/AKT/TSC1-2 pathway.
- Published
- 2016
- Full Text
- View/download PDF
28. Factors Affecting the Stabilization of Polyproline II Helices in a Hydrophobic Environment.
- Author
-
Zanna N, Milli L, Del Secco B, and Tomasini C
- Subjects
- Hydrophobic and Hydrophilic Interactions, Molecular Structure, Protein Conformation, Protein Structure, Secondary, Oxazolidinones chemistry, Peptides chemistry
- Abstract
Several parameters have a critical importance for the stabilization of either polyproline I (PPI) or polyproline II (PPII) helices in a hydrophobic environment. Among them, it was found out that the concentration is crucial as polyprolines at 3 mM concentration stably fold in PPII helices, that are organized in aggregates stable even after several days and are detectable by dynamic light scattering analysis. In more diluted concentration the same molecules stably fold in PPI helices, and no aggregates are found. In contrast, the introduction of a (4S,5R)-4-carboxy-5-methyloxazolidin-2-one (L-Oxd) moiety always inhibits the formation of the PPI helix, regardless of the L-Oxd position and the solution concentration.
- Published
- 2016
- Full Text
- View/download PDF
29. Cathepsin G activity lowers plasma LDL and reduces atherosclerosis.
- Author
-
Wang J, Sjöberg S, Tang TT, Oörni K, Wu W, Liu C, Secco B, Tia V, Sukhova GK, Fernandes C, Lesner A, Kovanen PT, Libby P, Cheng X, and Shi GP
- Abstract
Cathepsin G (CatG), a serine protease present in mast cells and neutrophils, can produce angiotensin-II (Ang-II) and degrade elastin. Here we demonstrate increased CatG expression in smooth muscle cells (SMCs), endothelial cells (ECs), macrophages, and T cells from human atherosclerotic lesions. In low-density lipoprotein (LDL) receptor-deficient (Ldlr(-/-)) mice, the absence of CatG reduces arterial wall elastin degradation and attenuates early atherosclerosis when mice consume a Western diet for 3months. When mice consume this diet for 6months, however, CatG deficiency exacerbates atherosclerosis in aortic arch without affecting lesion inflammatory cell content or extracellular matrix accumulation, but raises plasma total cholesterol and LDL levels without affecting high-density lipoprotein (HDL) or triglyceride levels. Patients with atherosclerosis also have significantly reduced plasma CatG levels that correlate inversely with total cholesterol (r=-0.535, P<0.0001) and LDL cholesterol (r=-0.559, P<0.0001), but not with HDL cholesterol (P=0.901) or triglycerides (P=0.186). Such inverse correlations with total cholesterol (r=-0.504, P<0.0001) and LDL cholesterol (r=-0.502, P<0.0001) remain significant after adjusting for lipid lowering treatments among this patient population. Human CatG degrades purified human LDL, but not HDL. This study suggests that CatG promotes early atherogenesis through its elastinolytic activity, but suppresses late progression of atherosclerosis by degrading LDL without affecting HDL or triglycerides., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
- View/download PDF
30. Pharmaceutical stabilization of mast cells attenuates experimental atherogenesis in low-density lipoprotein receptor-deficient mice.
- Author
-
Wang J, Sjöberg S, Tia V, Secco B, Chen H, Yang M, Sukhova GK, and Shi GP
- Subjects
- Animals, Anti-Asthmatic Agents pharmacology, Atherosclerosis drug therapy, Disease Models, Animal, Lipoproteins, LDL metabolism, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Receptors, LDL metabolism, Triglycerides metabolism, Vasculitis drug therapy, Vasculitis immunology, p-Methoxy-N-methylphenethylamine pharmacology, Atherosclerosis immunology, Cromolyn Sodium pharmacology, Lipoproteins, LDL deficiency, Mast Cells drug effects, Mast Cells immunology, Receptors, LDL genetics
- Abstract
Mast cells (MCs) contribute to atherogenesis by releasing pro-inflammatory mediators to activate vascular cells and other inflammatory cells. This study examined whether MC activation or stabilization affects diet-induced atherosclerosis in low-density lipoprotein receptor-deficient (Ldlr(-/-)) mice. When Ldlr(-/-) mice consumed an atherogenic diet for 3 or 6 months, MC activation with compound 48/80 (C48/80) increased aortic arch intima and total lesion areas, and plasma total cholesterol, LDL, and triglyceride levels, whereas MC stabilization with cromolyn reduced these parameters. There were significant differences in arch intima and total lesion areas, and plasma total cholesterol, LDL, and triglyceride levels between C48/80-treated and cromolyn-treated mice. To examine a therapeutic application of cromolyn in atherosclerosis, we fed Ldlr(-/-) mice an atherogenic diet for 3 months followed by giving mice cromolyn for additional 3 months. Cromolyn did not affect aortic arch intima area, but significantly reduced lipid deposition in the thoracic-abdominal aortas. In aortic arches, however, cromolyn treatment significantly reduced lesion contents of Mac-3(+) macrophages, CD4(+) T cells, activated MCs, and lesion cell proliferation. While plasma total cholesterol and LDL levels increased and high-density lipoprotein (HDL) levels decreased from 3 months to 6 months of an atherogenic diet, cromolyn treatment decreased significantly plasma total cholesterol, LDL, and triglyceride levels and increased HDL levels above those of 3-month time point. These observations demonstrate that MC stabilization reduces lesion inflammation, ameliorates plasma lipid profiles, and may serve as a potential therapy for this cardiovascular disease., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.