scholarly journals The tardigrade Hypsibius exemplaris  has the active mitochondrial alternative oxidase that could be studied at animal organismal level

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0244260
Author(s):  
Daria Wojciechowska ◽  
Milena Roszkowska ◽  
Łukasz Kaczmarek ◽  
Wiesława Jarmuszkiewicz ◽  
Andonis Karachitos ◽  
...  
Keyword(s):  
Animal Model ◽  
Membrane Potential ◽  
Therapeutic Strategy ◽  
Alternative Oxidase ◽  
Mitochondrial Respiratory Chain ◽  
Whole Body ◽  
Mitochondrial Inner Membrane ◽  
Behavior Observation ◽  
Cytochrome Pathway ◽  
The Impact

Mitochondrial alternative oxidase (AOX) is predicted to be present in mitochondria of several invertebrate taxa including tardigrades. Independently of the reason concerning the enzyme occurrence in animal mitochondria, expression of AOX in human mitochondria is regarded as a potential therapeutic strategy. Till now, relevant data were obtained due to heterologous AOX expression in cells and animals without natively expressed AOX. Application of animals natively expressing AOX could importantly contribute to the research. Thus, we decided to investigate AOX activity in intact specimens of the tardigrade Hypsibius exemplaris. We observed that H. exemplaris specimens’ tolerance to the blockage of the mitochondrial respiratory chain (MRC) cytochrome pathway was diminished in the presence of AOX inhibitor and the inhibitor-sensitive respiration enabled the tardigrade respiration under condition of the blockage. Importantly, these observations correlated with relevant changes of the mitochondrial inner membrane potential (Δψ) detected in intact animals. Moreover, detection of AOX at protein level required the MRC cytochrome pathway blockage. Overall, we demonstrated that AOX activity in tardigrades can be monitored by the animals’ behavior observation as well as by measurement of intact specimens’ whole-body respiration and Δψ. Furthermore, it is also possible to check the impact of the MRC cytochrome pathway blockage on AOX level as well as AOX inhibition in the absence of the blockage on animal functioning. Thus, H. exemplaris could be consider as a whole-animal model suitable to study AOX.

scholarly journals The tardigrade Hypsibius exemplaris as an emerging model to study the mitochondrial alternative oxidase at animal organismal level

2020 ◽  
Author(s):  
Daria Grobys ◽  
Milena Roszkowska ◽  
Łukasz Kaczmarek ◽  
Wiesława Jarmuszkiewicz ◽  
Andonis Karachitos ◽  
...  
Keyword(s):  
Animal Model ◽  
Protein Level ◽  
Therapeutic Strategy ◽  
Alternative Oxidase ◽  
Activity Analysis ◽  
Whole Body ◽  
Intact Specimen ◽  
Complex Iv ◽  
The Impact ◽  
In Cells

AbstractMitochondrial alternative oxidase (AOX) is present in mitochondria of many invertebrates. Independently of the reason concerning the enzyme occurrence in animal mitochondria, expression of AOX in human mitochondria is regarded as a potential therapeutic strategy. Till now, relevant data were obtained due to heterologous AOX expression in cells and animals without natively expressed AOX. Application of animals natively expressing AOX importantly contribute the research. Thus, we investigated Hypsibius exemplaris as a model for AOX activity analysis. We observed that H. exemplaris tolerance to the blockage of the MRC complexes was diminished in the presence of AOX inhibitor and the inhibitor-sensitive respiration enabled the tardigrade respiration under condition of the blockage. Furthermore, although detection of AOX at protein level and pronounced oxygraphic registration of its activity required the MRC complex blockage, the obtained data indicated that AOX clearly contributed animal functioning. We demonstrated that AOX activity in tardigrades, can be monitored by measurement of intact specimen whole-body respiration. Furthermore, it was also possible to monitor the impact of the MRC complex IV blockage on AOX expression and AOX inhibition in the absence of the blockage on animal functioning. Thus, H. exemplaris is applied as a whole-animal model suitable to study AOX.

scholarly journals The Tardigrade Hypsibius Exemplaris as an Emerging Model to Study the Mitochondrial Alternative Oxidase at Animal Organismal Level

2020 ◽  
Author(s):  
Daria Grobys ◽  
Milena Roszkowska ◽  
Łukasz Kaczmarek ◽  
Wiesława Jarmuszkiewicz ◽  
Andonis Karachitos ◽  
...  
Keyword(s):  
Alternative Oxidase ◽  
Mitochondrial Diseases ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Whole Body ◽  
Intact Specimen ◽  
Complex Iv ◽  
Animal Physiology ◽  
The Impact ◽  
First Time

Abstract Background: Mitochondrial alternative oxidase (AOX) is suggested to be present in mitochondria of most invertebrates but not vertebrates. Independently of the reason concerning the enzyme occurrence in animal mitochondria, expression of AOX in human mitochondria is regarded as a potential therapeutic strategy in treatment of mitochondrial diseases caused by the mitochondrial respiratory chain (MRC) deficiency or blockage. Undoubtedly, development of AOX expression-based therapy requires explanation of AOX contribution to animal physiology. Till now the relevant data has been obtained mainly due to heterologous AOX expression in cells and animals that do not have natively expressed AOX. We think that application of animals natively expressing AOX could importantly contribute to the research and therapy development. Because the available genomic and transcriptomic data suggests the presence of functional AOX protein in mitochondria of the tardigrade Hypsibius exemplaris, we decided to investigate the possibility of the animal application as a model for AOX activity analysis at organismal level.Results: We observed that H. exemplaris tolerance to the blockage of the MRC complexes III and/or IV was diminished in the presence of AOX inhibitor and the inhibitor-sensitive respiration enabled the tardigrade respiration under condition of the blockage. Furthermore, although detection of H. exemplaris AOX at protein level and pronounced oxygraphic registration of its activity required the MRC complex III and/or IV blockage, the obtained data indicated that AOX clearly contributed to the animal functioning, also in the absence of the blockage. Conclusions: According to our best knowledge we demonstrated, for the first time, that AOX activity of small aquatic invertebrates, represented by the studied tardigrade species, can be monitored by measurement of intact specimen whole-body respiration. Furthermore, it was also possible to monitor the impact of the MRC complex IV blockage on AOX expression level and AOX inhibition in the absence of the blockage on animal functioning. Thus, H. exemplaris could be applied as a whole-animal model suitable to study activity and expression regulation of natively expressed animal AOX.

scholarly journals Pyruvate transport by thermogenic-tissue mitochondria

1987 ◽  
Vol 247 (2) ◽  
pp. 441-447 ◽  
Author(s):  
M O Proudlove ◽  
R B Beechey ◽  
A L Moore
Keyword(s):  
Alternative Oxidase ◽  
Competitive Inhibition ◽  
Feedback Inhibition ◽  
Total Activity ◽  
Mitochondrial Inner Membrane ◽  
Pyruvate Oxidation ◽  
Cytochrome Pathway ◽  
Arum Maculatum ◽  
Long Chain ◽  
Sauromatum Guttatum

1. Mitochondria isolated from the thermogenic spadices of Arum maculatum and Sauromatum guttatum plants oxidized external NADH, succinate, citrate, malate, 2-oxoglutarate and pyruvate without the need to add exogenous cofactors. 2. Oxidation of substrates was virtually all via the alternative oxidase, the cytochrome pathway constituting only 10-20% of the total activity, depending on the stage of spadix development. 3. During later stages of spadix development, pyruvate oxidation was enhanced by the addition of aspartate. This was caused by acetyl-CoA condensing with oxaloacetate, produced from pyruvate/aspartate transamination, and so decreasing feedback inhibition of pyruvate dehydrogenase. 4. Pyruvate oxidation was inhibited by the long-chain acid maleimides AM5-11, but not by those with shorter polymethylene side groups, AM1-4. 5. The alpha-cyanocinnamate derivatives UK5099 [alpha-cyano-beta-(1-phenylindol-3-yl)acrylate] and CHCA [alpha-cyano-4-hydroxycinnamate] inhibited pyruvate-dependent O2 consumption and the carrier-mediated uptake of pyruvate across the mitochondrial inner membrane. Characteristics of non-competitive inhibition were observed for CHCA, whereas for UK5099 the results were more complex, suggesting a very low rate of dissociation of the inhibitor-carrier complex. 6. A comparison of the values of Vmax. and Km for oxidation and transport suggested that it was the latter which controls the overall rate of pyruvate oxidation by mitochondria from both tissues.

Fluorescent potentiometric dyes for membrane-potential imaging

1994 ◽  
Vol 52 ◽  
pp. 166-167
Author(s):  
Leslie M. Loew
Keyword(s):  
Membrane Potential ◽  
Single Cells ◽  
Quantitative Imaging ◽  
Optical Recording ◽  
Biological Processes ◽  
Major Focus ◽  
The Past ◽  
Excitable Systems ◽  
Major Application ◽  
The Impact

A major application of potentiometric dyes has been the multisite optical recording of electrical activity in excitable systems. After being championed by L.B. Cohen and his colleagues for the past 20 years, the impact of this technology is rapidly being felt and is spreading to an increasing number of neuroscience laboratories. A second class of experiments involves using dyes to image membrane potential distributions in single cells by digital imaging microscopy - a major focus of this lab. These studies usually do not require the temporal resolution of multisite optical recording, being primarily focussed on slow cell biological processes, and therefore can achieve much higher spatial resolution. We have developed 2 methods for quantitative imaging of membrane potential. One method uses dual wavelength imaging of membrane-staining dyes and the other uses quantitative 3D imaging of a fluorescent lipophilic cation; the dyes used in each case were synthesized for this purpose in this laboratory.

MicroRNA-520c-3p Modulates Doxorubicin-Chemosensitivity in HepG2 Cells

2020 ◽  
Vol 21 (2) ◽  
pp. 237-245 ◽  
Author(s):  
Mohamed A. Ragheb ◽  
Marwa H. Soliman ◽  
Emad M. Elzayat ◽  
Mervat S. Mohamed ◽  
Nada El-Ekiaby ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Therapeutic Strategy ◽  
Suppressive Effect ◽  
Expression Level ◽  
Tumor Suppressor Function ◽  
Protein Expression Level ◽  
Blot Technique ◽  
Induction Of Apoptosis ◽  
The Impact

Background: Doxorubicin (DOX) is the most common drugs used in cancer therapy, including Hepatocellular Carcinoma (HCC). Drug resistance, is one of chemotherapy’s significant problems. Emerging studies have shown that microRNAs (miRNAs) could participate in regulating this mechanism. Nevertheless, the impact of miRNAs on HCC chemoresistance is still enigmatic. Objective: Investigating the role of miR-520c-3p in enhancement of anti-tumor effect of DOX against HepG2 cells. Methods: Expression profile for liver related miRNAs (384 miRNAs) has been analyzed on HepG2 cells treated with DOX using qRT-PCR. miR-520c-3p, the most deregulated miRNA, was selected for combination treatment with DOX. Expression level for LEF1, CDK2, CDH1, VIM, Mcl-1 and TP53 was evaluated in miR-520c-3p transfected cells. Cell viability, colony formation, wound healing as well as apoptosis assays have been demonstrated. Furthermore, Mcl-1 protein level was measured using western blot technique. Results: The present data indicated that miR-520c-3p overexpression could render HepG2 cells chemo-sensitive to DOX through enhancing its suppressive effects on proliferation, migration, and induction of apoptosis. The suppressive effect of miR-520c-3p involved altering the expression levels of some key regulators of cell cycle, proliferation, migration and apoptosis including LEF1, CDK2, CDH1, VIM, Mcl-1 and TP53. Interestingly, Mcl-1 was found to be one of the potential targets of miR-520c-3p, and its protein expression level was down-regulated upon miR-520c-3p overexpression. Conclusion: Our data referred to the tumor suppressor function of miR-520c-3p that could modulate chemosensitivity of HepG2 cells toward DOX treatment, providing a promising therapeutic strategy in HCC.

A Melanocortin-4 Receptor Agonist Induces Skin and Hair Pigmentation in Patients with Monogenic Mutations in the Leptin-Melanocortin Pathway

2021 ◽  
pp. 1-10
Author(s):  
Varvara Kanti ◽  
Lia Puder ◽  
Irina Jahnke ◽  
Philipp Maximilian Krabusch ◽  
Jan Kottner ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Skin Pigmentation ◽  
Gene Mutations ◽  
Continuous Treatment ◽  
Whole Body ◽  
Hair Color ◽  
Phase 2 ◽  
Loss Of Function ◽  
The Impact ◽  
Over Time

<b><i>Background and Objectives:</i></b> Gene mutations within the leptin-melanocortin signaling pathway lead to severe early-onset obesity. Recently, a phase 2 trial evaluated new pharmacological treatment options with the MC4R agonist <i>setmelanotide</i> in patients with mutations in the genes encoding proopiomelanocortin (POMC) and leptin receptor (LEPR). During treatment with <i>setmelanotide,</i> changes in skin pigmentation were observed, probably due to off-target effects on the closely related melanocortin 1 receptor (MC1R). Here, we describe in detail the findings of dermatological examinations and measurements of skin pigmentation during this treatment over time and discuss the impact of these changes on patient safety. <b><i>Methods:</i></b> In an investigator-initiated, phase 2, open-label pilot study, 2 patients with loss-of-function POMC gene mutations and 3 patients with loss-of-function variants in LEPR were treated with the MC4R agonist <i>setmelanotide</i>. Dermatological examination, dermoscopy, whole body photographic documentation, and spectrophotometric measurements were performed at screening visit and approximately every 3 months during the course of the study. <b><i>Results:</i></b> We report the results of a maximum treatment duration of 46 months. Skin pigmentation increased in all treated patients, as confirmed by spectrophotometry. During continuous treatment, the current results indicate that elevated tanning intensity levels may stabilize over time. Lips and nevi also darkened. In red-haired study participants, hair color changed to brown after initiation of <i>setmelanotide</i> treatment. <b><i>Discussion:</i></b> <i>Setmelanotide</i> treatment leads to skin tanning and occasionally hair color darkening in both POMC- and LEPR-deficient patients. No malignant skin changes were observed in the patients of this study. However, the results highlight the importance of regular skin examinations before and during MC4R agonist treatment.

scholarly journals The Impact of Nordic Walking on Bone Properties in Postmenopausal Women with Pre-Diabetes and Non-Alcohol Fatty Liver Disease

2021 ◽  
Vol 18 (14) ◽  
pp. 7570
Author(s):  
Xiaming Du ◽  
Chao Zhang ◽  
Xiangqi Zhang ◽  
Zhen Qi ◽  
Sulin Cheng ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Postmenopausal Women ◽  
Fatty Liver Disease ◽  
Whole Body ◽  
Nordic Walking ◽  
Significant Group ◽  
Time Interaction ◽  
Bone Properties ◽  
The Impact

This study investigated the impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease (NAFLD). A total of 63 eligible women randomly participated in the Nordic walking training (AEx, n = 33), or maintained their daily lifestyle (Con, n = 30) during intervention. Bone mineral content (BMC) and density (BMD) of whole body (WB), total femur (TF), femoral neck (FN), and lumbar spine (L2-4) were assessed by dual-energy X-ray absorptiometry. Serum osteocalcin, pentosidine, receptor activator of nuclear factor kappa-B ligand (RANKL) levels were analyzed by ELISA assay. After an 8.6-month intervention, the AEx group maintained their BMCTF, BMDTF, BMCL2−4, and BMDL2−4, and increased their BMCFN (p = 0.016), while the Con group decreased their BMCTF (p = 0.008), BMDTF (p = 0.001), and BMDL2−4 (p = 0.002). However, no significant group × time interaction was observed, except for BMDL2−4 (p = 0.013). Decreased pentosidine was correlated with increased BMCWB(r = −0.352, p = 0.019). The intervention has no significant effect on osteocalcin and RANKL. Changing of bone mass was associated with changing of pentosidine, but not with osteocalcin and RANKL. Our results suggest that Nordic walking is effective in preventing bone loss among postmenopausal women with pre-diabetes and NAFLD.

scholarly journals The Effect of Repeated Whole-Body Cryotherapy on Sirt1 and Sirt3 Concentrations and Oxidative Status in Older and Young Men Performing Different Levels of Physical Activity

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 37
Author(s):  
Gabriela Wojciak ◽  
Jadwiga Szymura ◽  
Zbigniew Szygula ◽  
Joanna Gradek ◽  
Magdalena Wiecek
Keyword(s):  
Physical Activity ◽  
Young Men ◽  
Oxidative Status ◽  
Whole Body ◽  
Stress Index ◽  
Blood Levels ◽  
Long Distance ◽  
Antioxidant Defence ◽  
Whole Body Cryotherapy ◽  
The Impact

Background: The activity of antioxidant enzymes and sirtuins (Sirt) decreases along with age, which is counteracted by aerobic training. Sirtuins increase antioxidant defence. Whole-body cryotherapy (WBC) increases total antioxidant capacity (TAC) in young men. The aim of our study was to assess the impact of 24 WBC treatments on the blood concentration of selected sirtuins and the level of antioxidant defence as well as oxidative stress index of training and non-training men depending on age. Methods: The study involved 40 males. In each group, there were 10 non-training older and young men (60 NTR and 20 NTR), and 10 older and young long-distance runners (60 TR, 20 TR). During an 8-week period, participants underwent 24 WBC treatments (3 min −130 °C), which were performed three times a week (Monday, Wednesday, Friday). The concentrations of Sirt1, Sirt3, TAC, total oxidative status and the activity of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in the blood were determined before 1 WBC and after 1 WBC, 12 WBC and 24 WBC. Results: After 1 WBC, the activity of GPx and the concentration of Sirt1 and TAC in 60 TR and TAC in 60 NTR increased. After 12 WBC, the level of Sirt1 in 20 NTR and SOD in 20 TR increased. After 24 WBC, the level of Sirt1 increased in 60 TR and in 20 NTR, Sirt3 in 60 TR and SOD in 20 TR. Conclusions: Cryogenic temperatures increase blood levels of Sirt1 and Sirt3 and systemic antioxidant defence in men, but the effect is dependent on age, level of performed physical activity and the number of applied treatments.

scholarly journals Weight Status and Visceral Adiposity Mediate the Relationship between Exclusive Breastfeeding Duration and Skin Carotenoids in Later Childhood

2021 ◽  
Author(s):  
Ruyu Liu ◽  
Caitlyn G Edwards ◽  
Corinne N Cannavale ◽  
Isabel R Flemming ◽  
Morgan R Chojnacki ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Exclusive Breastfeeding ◽  
Weight Status ◽  
Mediating Effect ◽  
Physical Growth ◽  
Breastfeeding Duration ◽  
Whole Body ◽  
Controlled Clinical Trial ◽  
The Impact ◽  
The Relationship

Abstract Background Breastfeeding is associated with healthier weight and nutrient status in early life. However, the impact of breastfeeding on carotenoid status beyond infancy, and the influence of adiposity, is unknown. Objective The aim of the study was to retrospectively investigate the relationship between breastfeeding and carotenoid status, and the mediating effect of weight status and adiposity on this relationship among school-aged children. Methods This was a secondary analysis of baseline data collected from a randomized-controlled clinical trial. (ClinicalTrials.gov Identifier: NCT03521349). 7–12-year-old (n = 81) children were recruited from East-Central Illinois. Dual-energy x-ray absorptiometry (DXA) was used to assess visceral adipose tissue (VAT) and whole-body adiposity (%Fat). Weight was obtained to calculated body mass index percentile (BMI %ile). Skin carotenoids were assessed via reflection spectroscopy. Macular carotenoids were assessed as macular pigment optical density (MPOD). Dietary, birth, and breastfeeding information was self-reported by parents. Results Skin carotenoids were inversely related to %Fat (P &lt; 0.01), VAT (P &lt; 0.01) and BMI %ile (P &lt; 0.01). VAT and BMI %ile significantly mediated this relationship between exclusive breastfeeding duration and skin carotenoids, following adjustment for dietary carotenoids, energy intake, and mother education. Conclusions Weight status and adipose tissue distribution mediate the positive correlation between exclusive breastfeeding duration and skin carotenoids among children aged 7–12 years. The results indicate the need to support breastfeeding and healthy physical growth in childhood for optimal carotenoid status.

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