scholarly journals Thioredoxin-deficient mice, a novel phenotype sensitive to ambient air and hypersensitive to hyperoxia-induced lung injury

2015 ◽  
Vol 308 (5) ◽  
pp. L429-L442 ◽  
Author(s):  
Kumuda C. Das
Keyword(s):  
Energy Metabolism ◽  
Lung Injury ◽  
Nadh Dehydrogenase ◽  
Oxygen Toxicity ◽  
Ambient Air ◽  
Genotoxic Stress ◽  
Clinical Problem ◽  
Dominant Negative ◽  
Wild Type ◽  
Mitochondrial Energy Metabolism

Pulmonary oxygen toxicity is a major clinical problem for patients undergoing supplemental oxygen therapy. Thioredoxin (Trx) is an endogenous antioxidant protein that regenerates oxidatively inactivated proteins. We examined how Trx contributes to oxygen tolerance by creating transgenic mice with decreased levels of functional thioredoxin (dnTrx-Tg) using a dominant-negative approach. These mice showed decreased Trx activity in the lung although the expression of mutant protein is three times higher than the wild-type mice. Additionally, we found that these mice showed increased oxidation of endogenous Trx in room air. When exposed to hyperoxia (>90% O2) for 4 days, they failed to recover and showed significant mortality. Even in normal oxygen levels, these mice displayed a significant decrease in aconitase and NADH dehydrogenase activities, decreased mitochondrial energy metabolism, increased p53 and Gadd45α expression, and increased synthesis of proinflammatory cytokines. These effects were further increased by hyperoxia. We also generated mice overexpressing Trx (Trx-Tg) and found they maintained lung redox balance during exposure to high oxygen and thus were resistant to hyperoxia-induced lung injury. These mice had increased levels of reduced Trx in the lung in normoxia as well as hyperoxia. Furthermore, the levels of aconitase and NADH dehydrogenase activities were maintained in these mice concomitant with maintenance of mitochondrial energy metabolism. The genotoxic stress markers such as p53 or Gadd45α remained in significantly lower levels in hyperoxia compared with dnTrx-Tg or wild-type mice. These studies establish that mice deficient in functional Trx exhibit a phenotype of sensitivity to ambient air and hypersensitivity to hyperoxia.

scholarly journals Attenuating endogenous Fgfr2b ligands during bleomycin-induced lung fibrosis does not compromise murine lung repair

2015 ◽  
Vol 308 (10) ◽  
pp. L1014-L1024 ◽  
Author(s):  
BreAnne MacKenzie ◽  
Ingrid Henneke ◽  
Stefanie Hezel ◽  
Denise Al Alam ◽  
Elie El Agha ◽  
...  
Keyword(s):  
Lung Injury ◽  
Lung Fibrosis ◽  
Dominant Negative ◽  
Wild Type ◽  
Dominant Negative Form ◽  
Lung Epithelial ◽  
Organ Repair ◽  
The Impact ◽  
Negative Form

Fibroblast growth factors (Fgfs) mediate organ repair. Lung epithelial cell overexpression of Fgf10 postbleomycin injury is both protective and therapeutic, characterized by increased survival and attenuated fibrosis. Exogenous administration of FGF7 (palifermin) also showed prophylactic survival benefits in mice. The role of endogenous Fgfr2b ligands on bleomycin-induced lung fibrosis is still elusive. This study reports the expression of endogenous Fgfr2b ligands, receptors, and signaling targets in wild-type mice following bleomycin lung injury. In addition, the impact of attenuating endogenous Fgfr2b-ligands following bleomycin-induced fibrosis was tested by using a doxycycline (dox)-based inducible, soluble, dominant-negative form of the Fgfr2b receptor. Double-transgenic (DTG) Rosa26rtTA/+;tet(O)solFgfr2b mice were validated for the expression and activity of soluble Fgfr2b (failure to regenerate maxillary incisors, attenuated recombinant FGF7 signal in the lung). As previously reported, no defects in lung morphometry were detected in DTG (+dox) mice exposed from postnatal days (PN) 1 through PN105. Female single-transgenic (STG) and DTG mice were subjected to various levels of bleomycin injury (1.0, 2.0, and 3.0 U/kg). Fgfr2b ligands were attenuated either throughout injury ( days 0– 11; days 0– 28) or during later stages ( days 6– 28 and 14– 28). No significant changes in survival, weight, lung function, confluent areas of fibrosis, or hydroxyproline deposition were detected in DTG mice. These results indicate that endogenous Fgfr2b ligands do not significantly protect against bleomycin injury, nor do they expedite the resolution of bleomycin-induced lung injury in mice.

scholarly journals Activin Signaling: Effects on Body Composition and Mitochondrial Energy Metabolism

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3521-3529 ◽  
Author(s):  
Liunan Li ◽  
Joseph J. Shen ◽  
Juan C. Bournat ◽  
Lihua Huang ◽  
Abanti Chattopadhyay ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Energy Metabolism ◽  
Caloric Intake ◽  
Total Body Weight ◽  
Wild Type ◽  
Inner Mitochondrial Membrane ◽  
Indirect Measure ◽  
Mitochondrial Energy Metabolism ◽  
Activin Signaling ◽  
Obesity And Diabetes

Activin-βA and activin-βB (encoded by Inhba and Inhbb genes, respectively) are closely related TGF-β superfamily members that participate in a variety of biological processes. We previously generated mice with an insertion allele at the Inhba locus, InhbaBK. In this allele, the sequence encoding the Inhba mature domain is replaced with that of Inhbb, rendering the gene product functionally hypomorphic. Homozygous (InhbaBK/BK) and hemizygous (InhbaBK/−) mice are smaller and leaner than their wild-type littermates, and many tissues are disproportionately small relative to total body weight. To determine the mechanisms that contribute to these phenomena, we investigated the metabolic consequences of the mutation. Although the growth of InhbaBK mice is improved by providing a calorie-rich diet, diet-induced obesity, fatty liver, and insulin resistance (hallmarks of chronic caloric excess) do not develop, despite greater caloric intake than wild-type controls. Physiological, molecular, and biochemical analyses all revealed characteristics that are commonly associated with increased mitochondrial energy metabolism, with a corresponding up-regulation of several genes that reflect enhanced mitochondrial biogenesis and function. Oxygen consumption, an indirect measure of the metabolic rate, was markedly increased in InhbaBK/BK mice, and polarographic analysis of liver mitochondria revealed an increase in ADP-independent oxygen consumption, consistent with constitutive uncoupling of the inner mitochondrial membrane. These findings establish a functional relationship between activin signaling and mitochondrial energy metabolism and further support the rationale to target this signaling pathway for the medical treatment of cachexia, obesity, and diabetes.

Therapeutic Approaches Using Riboflavin in Mitochondrial Energy Metabolism Disorders

2016 ◽  
Vol 17 (13) ◽  
pp. 1527-1534 ◽  
Author(s):  
Bárbara J. Henriques ◽  
Tânia G. Lucas ◽  
Cláudio M. Gomes
Keyword(s):  
Energy Metabolism ◽  
Therapeutic Approaches ◽  
Mitochondrial Energy Metabolism

Mitochondrial energy metabolism is negatively regulated by cannabinoid receptor 1 in intact human epidermis

2020 ◽  
Vol 29 (7) ◽  
pp. 616-622 ◽  
Author(s):  
Attila Oláh ◽  
Majid Alam ◽  
Jérémy Chéret ◽  
Nikolett Gréta Kis ◽  
Zoltán Hegyi ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Cannabinoid Receptor ◽  
Human Epidermis ◽  
Cannabinoid Receptor 1 ◽  
Mitochondrial Energy Metabolism

scholarly journals The Role of Alcohol, LPS Toxicity, and ALDH2 in Dental Bony Defects

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 651
Author(s):  
Hsiao-Cheng Tsai ◽  
Che-Hong Chen ◽  
Daria Mochly-Rosen ◽  
Yi-Chen Ethan Li ◽  
Min-Huey Chen
Keyword(s):  
Bone Loss ◽  
Bacterial Infection ◽  
Bone Regeneration ◽  
Alcohol Drinking ◽  
Bacterial Species ◽  
Dominant Negative ◽  
Enzyme Inactivation ◽  
Wild Type ◽  
Micro Computed Tomography ◽  
Dominant Negative Mutation

It is estimated that 560 million people carry an East Asian-specific ALDH2*2 dominant-negative mutation which leads to enzyme inactivation. This common ALDH2 polymorphism has a significant association with osteoporosis. We hypothesized that the ALDH2*2 mutation in conjunction with periodontal Porphyromonas gingivalis bacterial infection and alcohol drinking had an inhibitory effect on osteoblasts and bone regeneration. We examined the prospective association of ALDH2 activity with the proliferation and mineralization potential of human osteoblasts in vitro. The ALDH2 knockdown experiments showed that the ALDH2 knockdown osteoblasts lost their proliferation and mineralization capability. To mimic dental bacterial infection, we compared the dental bony defects in wild-type mice and ALDH2*2 knockin mice after injection with purified lipopolysaccharides (LPS), derived from P. gingivalis which is a bacterial species known to cause periodontitis. Micro-computed tomography (micro-CT) scan results indicated that bone regeneration was significantly affected in the ALDH2*2 knockin mice with about 20% more dental bony defects after LPS injection than the wild-type mice. Moreover, the ALDH2*2 knockin mutant mice had decreased osteoblast growth and more dental bone loss in the upper left jaw region after LPS injection. In conclusion, these results indicated that the ALDH2*2 mutation with alcohol drinking and chronic exposure to dental bacterial-derived toxin increased the risk of dental bone loss.

scholarly journals Mitochondrial P2X7 receptor localization modulates energy metabolism enhancing physical performance

Function ◽  
2021 ◽  
Author(s):  
Alba Clara Sarti ◽  
Valentina Vultaggio-Poma ◽  
Simonetta Falzoni ◽  
Sonia Missiroli ◽  
Anna Lisa Giuliani ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Physical Fitness ◽  
P2x7 Receptor ◽  
Human Fibroblasts ◽  
Atp Synthesis ◽  
Heart Tissue ◽  
Mitochondrial Potential ◽  
Mitochondrial Energy Metabolism ◽  
Microglia Cell ◽  
Basal Expression

Abstract Basal expression of the P2X7 receptor (P2X7R) improves mitochondrial metabolism, ATP synthesis and overall fitness of immune and non-immune cells. We investigated P2X7R contribution to energy metabolism and subcellular localization in fibroblasts (mouse embryo fibroblasts and HEK293 human fibroblasts), mouse microglia (primary brain microglia and the N13 microglia cell line), and heart tissue. The P2X7R localizes to mitochondria, and its lack a) decreases basal respiratory rate, ATP-coupled respiration, maximal uncoupled respiration, resting mitochondrial potential, mitochondrial matrix Ca2+ level, b) modifies expression pattern of oxidative phosphorylation (OxPhos) enzymes, and c) severely affects cardiac performance. Hearts from P2rx7-deleted versus WT mice are larger, heart mitochondria smaller, and stroke volume (SV), ejection fraction (EF), fractional shortening (FS) and cardiac output (CO), are significantly decreased. Accordingly, physical fitness of P2X7R-null mice is severely reduced. Thus, the P2X7R is a key modulator of mitochondrial energy metabolism and a determinant of physical fitness.

scholarly journals A network of Rab GTPases controls phagosome maturation and is modulated by Salmonella enterica serovar Typhimurium

2007 ◽  
Vol 176 (3) ◽  
pp. 263-268 ◽  
Author(s):  
Adam C. Smith ◽  
Won Do Heo ◽  
Virginie Braun ◽  
Xiuju Jiang ◽  
Chloe Macrae ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Dominant Negative ◽  
Rab Gtpases ◽  
Wild Type ◽  
Intracellular Growth ◽  
Non Invasive ◽  
Serovar Typhimurium ◽  
Guanosine Triphosphatase ◽  
Kinetics Of

Members of the Rab guanosine triphosphatase (GTPase) family are key regulators of membrane traffic. Here we examined the association of 48 Rabs with model phagosomes containing a non-invasive mutant of Salmonella enterica serovar Typhimurium (S. Typhimurium). This mutant traffics to lysosomes and allowed us to determine which Rabs localize to a maturing phagosome. In total, 18 Rabs associated with maturing phagosomes, each with its own kinetics of association. Dominant-negative mutants of Rab23 and 35 inhibited phagosome–lysosome fusion. A large number of Rab GTPases localized to wild-type Salmonella-containing vacuoles (SCVs), which do not fuse with lysosomes. However, some Rabs (8B, 13, 23, 32, and 35) were excluded from wild-type SCVs whereas others (5A, 5B, 5C, 7A, 11A, and 11B) were enriched on this compartment. Our studies demonstrate that a complex network of Rab GTPases controls endocytic progression to lysosomes and that this is modulated by S. Typhimurium to allow its intracellular growth.

Dissociation between alveolar transmigration of neutrophils and lung injury in hyperoxia

2006 ◽  
Vol 291 (5) ◽  
pp. L1050-L1058 ◽  
Author(s):  
Sandra Perkowski ◽  
Arnaud Scherpereel ◽  
Juan-Carlos Murciano ◽  
Evguenia Arguiri ◽  
Charalambos C. Solomides ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Lung Injury ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Wild Type ◽  
Pulmonary Endothelium ◽  
Pulmonary Uptake ◽  
Endothelial Surface ◽  
Platelet Endothelial Cell Adhesion ◽  
Cell Adhesion Molecule 1

The objective of this study was to quantitatively assess changes in cell adhesion molecule (CAM) expression on the pulmonary endothelial surface during hyperoxia and to assess the functional significance of those changes on cellular trafficking and development of oxygen-induced lung injury. Mice were placed in >95% O2 for 0–72 h, and pulmonary injury and neutrophil (PMN) sequestration were assessed. Specific pulmonary CAM expression was quantified with a dual-radiolabeled MAb technique. To test the role of CAMs in PMN trafficking during hyperoxia, blocking MAbs to murine P-selectin, ICAM-1, or platelet-endothelial cell adhesion molecule-1 (PECAM-1) were injected in wild-type mice. Mice genetically deficient in these CAMs and PMN-depleted mice were also evaluated. PMN sequestration occurred within 8 h of hyperoxia, although alveolar emigration occurred later (between 48 and 72 h), coincident with rapid escalation of the lung injury. Hyperoxia significantly increased pulmonary uptake of radiolabeled antibodies to P-selectin, ICAM-1, and PECAM-1, reflecting an increase in their level on pulmonary endothelium and possibly sequestered blood cells. Although both anti-PECAM-1 and anti-ICAM-1 antibodies suppressed PMN alveolar influx in wild-type mice, only mice genetically deficient in PECAM-1 showed PMN influx suppression. Neither CAM blockade, nor genetic deficiency, nor PMN depletion attenuated lung injury. We conclude that early pulmonary PMN retention during hyperoxia is not temporally associated with an increase in endothelial CAMs; however, subsequent PMN emigration into the alveolar space may be supported by PECAM-1 and ICAM-1. Blocking PMN recruitment did not prevent lung injury, supporting dissociation between PMN infiltration and lung injury during hyperoxia in mice.

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