scholarly journals Sirt5 Deficiency Causes Posttranslational Protein Malonylation and Dysregulated Cellular Metabolism in Chondrocytes Under Obesity Conditions

Cartilage ◽  
2021 ◽  
pp. 194760352199320
Author(s):  
Shouan Zhu ◽  
Albert Batushansky ◽  
Anita Jopkiewicz ◽  
Dawid Makosa ◽  
Kenneth M. Humphries ◽  
...  
Keyword(s):  
Cellular Metabolism ◽  
Tca Cycle ◽  
Gas Chromatography Mass Spectrometry ◽  
Dependent Manner ◽  
Joint Injury ◽  
Primary Chondrocytes ◽  
Wide Range ◽  
Chondrocyte Metabolism ◽  
High Concentrations

Objective Obesity accelerates the development of osteoarthritis (OA) during aging and is associated with altered chondrocyte cellular metabolism. Protein lysine malonylation (MaK) is a posttranslational modification (PTM) that has been shown to play an important role during aging and obesity. The objective of this study was to investigate the role of sirtuin 5 (Sirt5) in regulating MaK and cellular metabolism in chondrocytes under obesity-related conditions. Methods MaK and SIRT5 were immunostained in knee articular cartilage of obese db/db mice and different aged C57BL6 mice with or without destabilization of the medial meniscus surgery to induce OA. Primary chondrocytes were isolated from 7-day-old WT and Sirt5−/− mice and treated with varying concentrations of glucose and insulin to mimic obesity. Sirt5-dependent effects on MaK and metabolism were evaluated by western blot, Seahorse Respirometry, and gas/chromatography-mass/spectrometry (GC-MS) metabolic profiling. Results MaK was significantly increased in cartilage of db/db mice and in chondrocytes treated with high concentrations of glucose and insulin (GluhiInshi). Sirt5 was increased in an age-dependent manner following joint injury, and Sirt5 deficient primary chondrocytes had increased MaK, decreased glycolysis rate, and reduced basal mitochondrial respiration. GC-MS identified 41 metabolites. Sirt5 deficiency altered 13 distinct metabolites under basal conditions and 18 metabolites under GluhiInshi treatment. Pathway analysis identified a wide range of Sirt5-dependent altered metabolic pathways that include amino acid metabolism, TCA cycle, and glycolysis. Conclusion This study provides the first evidence that Sirt5 broadly regulates chondrocyte metabolism. We observed changes in SIRT5 and MaK levels in cartilage with obesity and joint injury, suggesting that the Sirt5-MaK pathway may contribute to altered chondrocyte metabolism that occurs during OA development.

scholarly journals Sirt5 deficiency causes post-translational protein malonylation and dysregulated cellular metabolism in chondrocytes under obesity conditions

2020 ◽  
Author(s):  
Shouan Zhu ◽  
Albert Batushansky ◽  
Anita Jopkiewicz ◽  
Dawid Makosa ◽  
Kenneth M. Humphries ◽  
...  
Keyword(s):  
Cellular Metabolism ◽  
Tca Cycle ◽  
Gas Chromatography Mass Spectrometry ◽  
Dependent Manner ◽  
Joint Injury ◽  
Primary Chondrocytes ◽  
Wide Range ◽  
Chondrocyte Metabolism ◽  
High Concentrations

ABSTRACTObjectiveObesity accelerates the development of osteoarthritis (OA) during aging and is associated with altered chondrocyte cellular metabolism. The objective of this study was to investigate the role of sirtuin 5 (SIRT5) in regulating chondrocyte protein lysine malonylation (MaK) and cellular metabolism under obesity-related conditions.MethodsMaK and SIRT5 were immunostained in knee articular cartilage of obese db/db mice and different aged C57BL6 mice with or without destabilization of the medial meniscus (DMM) surgery to induce OA. Primary chondrocytes were isolated from 7-day-old WT and Sirt5−/− mice and treated with varying concentrations of glucose and insulin to mimic obesity. Sirt5-dependent effects on MaK and metabolism were evaluated by Western blot, Seahorse Respirometry, and gas/chromatography-mass/spectrometry (GC-MS) metabolic profiling.ResultsMaK was significantly increased in cartilage of db/db mice and in chondrocytes treated with high concentrations of glucose and insulin (GluhiInshi). Sirt5 protein was increased in an age-dependent manner following joint injury, and Sirt5 deficient primary chondrocytes had increased MaK, decreased glycolysis rate, and reduced basal mitochondrial respiration. GC-MS identified 41 metabolites. Sirt5 deficiency altered 13 distinct metabolites under basal conditions and 18 metabolites under GluhiInshi treatment. Pathway analysis identified a wide range of Sirt5-dependent altered metabolic pathways that include amino acid metabolism, TCA cycle, and glycolysis.ConclusionThis study provides the first evidence that Sirt5 broadly regulates chondrocyte metabolism. We observed changes in Sirt5 and MaK levels in cartilage with obesity and joint injury, suggesting that the Sirt5-MaK pathway may contribute to altered chondrocyte metabolism that occurs during OA development.

scholarly journals A Possible Role of Allatostatin C in Inhibiting Ecdysone Biosynthesis Revealed in the Mud Crab Scylla paramamosain

2021 ◽  
Vol 8 ◽  
Author(s):  
An Liu ◽  
Wenyuan Shi ◽  
Dongdong Lin ◽  
Haihui Ye
Keyword(s):  
Scylla Paramamosain ◽  
Dependent Manner ◽  
Mud Crab ◽  
Methyl Farnesoate ◽  
Independent Manner ◽  
Wide Range ◽  
Negative Effect

C-type allatostatins (C-type ASTs) are a family of structurally related neuropeptides found in a wide range of insects and crustaceans. To date, the C-type allatostatin receptor in crustaceans has not been deorphaned, and little is known about its physiological functions. In this study, we aimed to functionally define a C-type ASTs receptor in the mud crab, Scylla paramamosian. We showed that C-type ASTs receptor can be activated by ScypaAST-C peptide in a dose-independent manner and by ScypaAST-CCC peptide in a dose-dependent manner with an IC50 value of 6.683 nM. Subsequently, in vivo and in vitro experiments were performed to investigate the potential roles of ScypaAST-C and ScypaAST-CCC peptides in the regulation of ecdysone (20E) and methyl farnesoate (MF) biosynthesis. The results indicated that ScypaAST-C inhibited biosynthesis of 20E in the Y-organ, whereas ScypaAST-CCC had no effect on the production of 20E. In addition, qRT-PCR showed that both ScypaAST-C and ScypaAST-CCC significantly decreased the level of expression of the MF biosynthetic enzyme gene in the mandibular organ, suggesting that the two neuropeptides have a negative effect on the MF biosynthesis in mandibular organs. In conclusion, this study provided new insight into the physiological roles of AST-C in inhibiting ecdysone biosynthesis. Furthermore, it was revealed that AST-C family peptides might inhibit MF biosynthesis in crustaceans.

Effects of polymethoxylated flavone metabolites on apoB100 secretion and MTP activity in Huh7.5 cells

2021 ◽  
Vol 18 ◽  
Author(s):  
Danielle R. Gonçalves ◽  
Thais B. Cesar ◽  
John A. Manthey ◽  
Paulo I. Costa
Keyword(s):  
Lipid Synthesis ◽  
Dependent Manner ◽  
Transfer Protein ◽  
Low Concentrations ◽  
Wide Range ◽  
Cell Assays ◽  
Polymethoxylated Flavones ◽  
High Concentrations

Background: Citrus polymethoxylated flavones (PMFs) reduce the synthesis of liver lipoproteins in animal and in vitro cell assays, but few studies have evaluated the direct effects of their metabolites on this highly regulated process. Objective: To investigate the effects of representative metabolites of PMF on the secretion of liver lipoproteins using the mammalian cell Huh7.5. Method: In this study, the influences of three PMFs and five previously isolated PMF metabolites on hepatic apoB-100 secretion and microsomal transfer protein (MTP) activity were evaluated. Tangeretin (TAN), nobiletin (NOB) and 3,5,6,7,8,3′,4′-heptamethoxyflavone (HMF), and their glucuronides (TAN-Gluc, NOB-Gluc and HMF-Gluc) and oxidatively demethylated metabolites (TAN-OH, NOB-OH, HMF-OH) were incubated with Huh7.5 cells to measure their inhibitory effects on lipid synthesis. Results: The results showed that TAN, HMF and TAN-OH reduced the secretion of apoB-100 in a dose-dependent manner, while NOB and the other tested metabolites showed no inhibition. MTP activity in the Huh7.5 cells was significantly reduced in the presence of low concentrations of TAN, and in high concentrations of NOB-OH. This study also showed that PMFs and PMF metabolites produced a wide range of effects on apoB-100 secretion and MTP activity. Conclusion: The results suggest that while PMFs and their metabolites control dyslipidemia in vivo, the inhibition of MTP activity cannot be the only pathway influenced by these compounds.

RAPID FORMATION OF LARGE MOLECULAR WEIGHT O-P0LYMERS IN CROSSLINKED FIBRIN INDUCED BY HIGH FACTOR XIII CONCENTRATIONS: ROLE OF PLATELET FACTOR XIII.

1987 ◽  
Author(s):  
C W Francis ◽  
V J Marder
Keyword(s):  
Factor Xiii ◽  
Factor Xiiia ◽  
Freezing And Thawing ◽  
Platelet Factor ◽  
Polymer Formation ◽  
Wide Range ◽  
Sequential Addition ◽  
High Concentrations ◽  
A Chain

Following fibrin polymerization, activated factor XIII stabilizes the clot by catalyzing the formation of specific intermolecular covalent crosslinks between pairs of y chains to form dimers and also among two or more a chains to form polymers. We have identified a series of previously uncharacterized a chain polymers with a wide range of sizes, including some with apparent Mr in excess of several million. Additionally, we establish the role of high concentrations of factor XIII in the extent and rate of α-polymer formation and provide evidence that the factor XIII required can be provided by platelets. Using SDS gel electrophoresis, we find that fibrin prepared from purified fibrinogen or from platelet-deficient plasma contains a series of 21 factor XIIIa crosslinked a chain polymers with Mr from 140,000 to 770,000. The mean Mr difference between individual polymers of 32,000 is consistent with a staggered, overlapping sequential addition of monomers to the growing α-polymer chain. In plasma containing no platelets, α-polymer formation was incomplete with residual α-monomer remaining. Progressively higher platelet counts facilitated more rapid crosslinking of a chains into larger polymers. Intact platelets were not required to promote crosslinking, since platelets lysed by freezing and thawing were also effective. Enrichment of plasma with placental factor XIII in an amount equal to that contained in platelets was as effective as platelets in accelerating the rate of formation and increasing the size of α-chain polymers. We conclude that platelets are a principal source of factor XIII for maximal fibrin stabilization, providing a larger quantity than is available from plasma alone and regulating both the rate and extent of α-polymer formation in thrombi or hemostatic plugs at sites of vascular injury.

Hydrogen sulfide mediates vasoactivity in an O2-dependent manner

2007 ◽  
Vol 292 (4) ◽  
pp. H1953-H1960 ◽  
Author(s):  
Jeffrey R. Koenitzer ◽  
T. Scott Isbell ◽  
Hetal D. Patel ◽  
Gloria A. Benavides ◽  
Dale A. Dickinson ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Vascular Function ◽  
Acid Metabolism ◽  
Rat Aorta ◽  
Organ Bath ◽  
Dependent Manner ◽  
High Concentrations ◽  
Rapid Contraction

Hydrogen sulfide (H2S) has recently been shown to have a signaling role in vascular cells. Similar to nitric oxide (NO), H2S is enzymatically produced by amino acid metabolism and can cause posttranslational modification of proteins, particularly at thiol residues. Molecular targets for H2S include ATP-sensitive K+channels, and H2S may interact with NO and heme proteins such as cyclooxygenase. It is well known that the reactions of NO in the vasculature are O2dependent, but this has not been addressed in most studies designed to elucidate the role of H2S in vascular function. This is important, since H2S reactions can be dramatically altered by the high concentrations of O2used in cell culture and organ bath experiments. To test the hypothesis that the effects of H2S on the vasculature are O2dependent, we have measured real-time levels of H2S and O2in respirometry and vessel tension experiments, as well as the associated vascular responses. A novel polarographic H2S sensor developed in our laboratory was used to measure H2S levels. Here we report that, in rat aorta, H2S concentrations that mediate rapid contraction at high O2levels cause rapid relaxation at lower physiological O2levels. At high O2, the vasoconstrictive effect of H2S suggests that it may not be H2S per se but, rather, a putative vasoactive oxidation product that mediates constriction. These data are interpreted in terms of the potential for H2S to modulate vascular tone in vivo.

Diarylheptanoids: Potent Anticancer Agents

2021 ◽  
Vol 08 ◽  
Author(s):  
Rabia Hameed
Keyword(s):  
T Cell Activation ◽  
Anticancer Agents ◽  
Cell Activation ◽  
Dependent Manner ◽  
Current Review ◽  
Tnf Α ◽  
Wide Range ◽  
The Family ◽  
Dose Dependent

Abstract: Diarylheptanoids are widely distributed among species belonging to the family Betulaceae. Being highly polar in nature, they can either be isolated from plants by using sophisticated chromatographic techniques or can be synthesized in the laboratory. They are found to exhibit a wide range of activities, from very simple analgesics to anticancer agents. Recently, they have gained considerable attention due to inhibitory activity against NF-κB activation, NO and TNF-α production, reduction in NO and COX-2 levels in a dose-dependent manner, and suppression of T-cell activation. The current review article highlights the role of diarylheptanoids as potent anticancer agents in a variety of cancers.

scholarly journals Protein disulfide-isomerase mediates delivery of nitric oxide redox derivatives into platelets

2007 ◽  
Vol 403 (2) ◽  
pp. 283-288 ◽  
Author(s):  
Susannah E. Bell ◽  
Chirag M. Shah ◽  
Michael P. Gordge
Keyword(s):  
Protein Disulfide Isomerase ◽  
Human Platelets ◽  
Dependent Manner ◽  
Disulfide Isomerase ◽  
Angeli's Salt ◽  
Wide Range ◽  
Nitrosonium Cation ◽  
Protein Disulfide ◽  
Dose Dependent

S-nitrosothiol compounds are important mediators of NO signalling and can give rise to various redox derivatives of NO: nitrosonium cation (NO+), nitroxyl anion (NO−) and NO• radical. Several enzymes and transporters have been implicated in the intracellular delivery of NO from S-nitrosothiols. In the present study we have investigated the role of GPx (glutathione peroxidase), the L-AT (L-amino acid transporter) system and PDI (protein disulfide-isomerase) in the delivery of NO redox derivatives into human platelets. Washed human platelets were treated with inhibitors of GPx, L-AT and PDI prior to exposure to donors of NO redox derivatives (S-nitrosoglutathione, Angeli's salt and diethylamine NONOate). Rapid delivery of NO-related signalling into platelets was monitored by cGMP accumulation and DAF-FM (4-amino-5-methylamino-2′7′-difluorofluorescein) fluorescence. All NO redox donors produced both a cGMP response and DAF-FM fluorescence in target platelets. NO delivery was blocked by inhibition of PDI in a dose-dependent manner. In contrast, inhibition of GPx and L-AT had only a minimal effect on NO-related signalling. PDI activity is therefore required for the rapid delivery into platelets of NO-related signals from donors of all NO redox derivatives. GPx and the L-AT system appeared to be unimportant in rapid NO signalling by the compounds used in the present study. This does not, however, exclude a possible role during exposure of cells to other S-nitrosothiol compounds, such as S-nitrosocysteine. These results further highlight the importance of PDI in mediating the action of a wide range of NO-related signals.

scholarly journals Precipitation of CaCO3 Polymorphs from Aqueous Solutions: The Role of pH and Sulphate Groups

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 178 ◽  
Author(s):  
Iris Cuesta Mayorga ◽  
José Manuel Astilleros ◽  
Lurdes Fernández-Díaz
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Reaction Times ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Wide Range ◽  
Ph Conditions ◽  
High Concentrations ◽  
Edx Microanalysis

In this work, we aimed to experimentally study the nucleation and growth of CaCO3 phases precipitated from supersaturated aqueous solutions in the presence of varying concentrations of sulphate oxyanion. The experiments were conducted under pH conditions close to neutral (7.6) and by considering a wide range of initial (SO42−)/(CO32−) ratios (0 to approx. 68) in the aqueous solution. We paid special attention to the evolution of the precipitates during ageing within a time framework of 14 days. The mineralogy, morphology, and composition of the precipitates were studied by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and EDX microanalysis. The concentration of sulphate ions in the reacted aqueous solution was studied by ICPs. The experimental results showed that the mineral composition of the precipitate recovered in each run varied with the (SO42−)/(CO32−) ratio in the parental solution, which influenced the mineral evolution of the precipitates during ageing. We observed that high concentrations of sulphate in the aqueous solution stabilized the vaterite precipitates and inhibited calcite formation. Furthermore, aragonite never precipitated directly from the solution, and it was only formed via a dissolution-precipitation process in solutions with a high (SO42−)/(CO32−) ratio after long reaction times. Finally, gypsum only precipitated after long ageing in those aqueous solutions with the highest concentration of sulphate. The reaction pathways during ageing, the morphology of the calcite crystals, and the composition of vaterite and calcite were discussed considering both kinetic and thermodynamic factors. These results showed a considerably more complex behavior of the system than that observed in experiments conducted under higher pHs and supersaturation levels and lower (SO42−)/(CO32−) ratios in the aqueous phase.

scholarly journals The Surface-Exposed Carboxyl Region of Mycoplasma pneumoniae Elongation Factor Tu Interacts with Fibronectin

2008 ◽  
Vol 76 (7) ◽  
pp. 3116-3123 ◽  
Author(s):  
Sowmya Balasubramanian ◽  
T. R. Kannan ◽  
Joel B. Baseman
Keyword(s):  
Mycoplasma Pneumoniae ◽  
Elongation Factor ◽  
Bacterial Pathogen ◽  
Immunogold Electron Microscopy ◽  
Elongation Factor Tu ◽  
Dependent Manner ◽  
Human Respiratory Tract ◽  
Amino Acid Region ◽  
Wide Range

ABSTRACT Mycoplasma pneumoniae is a bacterial pathogen of the human respiratory tract that causes a wide range of airway diseases as well as extrapulmonary symptoms. It possesses a distinct, differentiated terminal structure, termed the attachment organelle, that mediates adherence to the host respiratory epithelium. Previously, we reported that surface-associated M. pneumoniae elongation factor Tu (EF-Tu, also called MPN665) serves as a fibronectin (Fn)-binding protein, facilitating interactions between mycoplasmas and extracellular matrix. In the present study, we determined that binding of M. pneumoniae EF-Tu to Fn is primarily mediated by the EF-Tu carboxyl region. A 179-amino-acid region spanning the carboxyl terminus (designated EC; amino acids 192 to 394) binds Fn in a dose-dependent manner. Further analysis of carboxyl constructs (ED3 and ED4) and their deletion truncations (ED3.1, ED3.2, and ED4.1) revealed that the carboxyl region possessed two distinct sites with different Fn-binding efficiencies. Immunogold electron microscopy using antibodies raised against recombinant ED3 and ED4 demonstrated the surface accessibility of the EF-Tu carboxyl region. Competitive binding assays using intact radiolabeled mycoplasmas and purified recombinant ED3 and ED4 proteins, along with antibody blocking assays, reinforced the role of the surface-exposed EF-Tu carboxyl region in Fn binding. Alkali and high-salt treatment of mycoplasma membranes and Triton X-114-partitioned mycoplasma fractions confirmed the stable association of EF-Tu within the mycoplasma membrane. These observations highlight the unique, multifaceted, and unpredictable role of the classically defined cytoplasmic protein EF-Tu relative to cellular function, compartmentalization, and topography.

scholarly journals Generation of Variability in Chrysodeixis includens Nucleopolyhedrovirus (ChinNPV): The Role of a Single Variant

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1895
Author(s):  
Eduardo Aguirre ◽  
Inés Beperet ◽  
Trevor Williams ◽  
Primitivo Caballero
Keyword(s):  
Genetic Variant ◽  
Dependent Manner ◽  
Nucleotide Polymorphisms ◽  
Concentration Dependent Manner ◽  
Culture Cells ◽  
Natural Isolates ◽  
High Concentrations ◽  
K Variant ◽  
Chrysodeixis Includens

The mechanisms generating variability in viruses are diverse. Variability allows baculoviruses to evolve with their host and with changes in their environment. We examined the role of one genetic variant of Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) and its contribution to the variability of the virus under laboratory conditions. A mixture of natural isolates (ChinNPV-Mex1) contained two genetic variants that dominated over other variants in individual larvae that consumed high (ChinNPV-K) and low (ChinNPV-E) concentrations of inoculum. Studies on the ChinNPV-K variant indicated that it was capable of generating novel variation in a concentration-dependent manner. In cell culture, cells inoculated with high concentrations of ChinNPV-K produced OBs with the ChinNPV-K REN profile, whereas a high diversity of ChinNPV variants was recovered following plaque purification of low concentrations of ChinNPV-K virion inoculum. Interestingly, the ChinNPV-K variant could not be recovered from plaques derived from low concentration inocula originating from budded virions or occlusion-derived virions of ChinNPV-K. Genome sequencing revealed marked differences between ChinNPV-K and ChinNPV-E, with high variation in the ChinNPV-K genome, mostly due to single nucleotide polymorphisms. We conclude that ChinNPV-K is an unstable genetic variant that is responsible for generating much of the detected variability in the natural ChinNPV isolates used in this study.

Sign in / Sign up

Export Citation Format

Share Document