scholarly journals Methylenetetrahydrofolate reductase deficiency alters cellular response after ischemic stroke in male mice

2019 ◽  
Author(s):  
Jamie E. Abato ◽  
Mahira Moftah ◽  
Greg O. Cron ◽  
Patrice D. Smith ◽  
Nafisa M. Jadavji
Keyword(s):  
Ischemic Stroke ◽  
Brain Tissue ◽  
Cellular Response ◽  
Methylenetetrahydrofolate Reductase ◽  
Critical Role ◽  
Antioxidant Response ◽  
Related Factor ◽  
Wild Type ◽  
Wild Type Littermate ◽  
Damage Site

AbstractObjectiveElevated homocysteine concentrations are a risk factor for stroke. A common genetic polymorphism in methylenetetrahydrofolate reductase (MTHFR 677 C➔T) results in elevated levels of homocysteine. MTHFR plays a critical role in the synthesis of S-adenosylmethionine (SAM), a global methyl donor. Our previous work has demonstrated that Mthfr+/− mice, which model the MTHFR polymorphism in humans, are more vulnerable to ischemic damage. The aim of this study was to investigate the cellular mechanisms by which the MTHFR-deficiency changes the brain in the context of ischemic stroke injury.MethodsIn the present study, three-month-old male Mthfr+/− and wild-type littermate mice were subjected to photothrombosis (PT) damage. Four weeks after PT damage, animals were tested on behavioral tasks, in vivo imaging was performed using T2-weighted MRI, and brain tissue was collected.ResultsMthfr+/− animals used their non-impaired forepaw more during to explore the cylinder and had a larger damage volume compared to wild-type littermates. In brain tissue of Mthfr+/− mice methionine adenosyltransferase II alpha (MAT2A) protein levels were decreased within the damage hemisphere and increased levels in hypoxia induced factor 1 alpha (HIF-1α) in non-damage hemisphere. There was an increased antioxidant response in the damage site as indicated by higher levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and superoxide dismutase 2 (SOD2).ConclusionsOur results suggest that Mthfr+/− mice are more vulnerable to PT-induced stroke damage through regulation of the cellular response. The increased antioxidant response we observed may be compensatory to the damage amount.

scholarly journals Decreased connexin43 expression in the mouse heart potentiates pacing-induced remodeling of repolarizing currents

2008 ◽  
Vol 295 (5) ◽  
pp. H1905-H1916 ◽  
Author(s):  
Andrianos Kontogeorgis ◽  
Xiaodong Li ◽  
Eunice Y. Kang ◽  
Jonathan E. Feig ◽  
Marc Ponzio ◽  
...  
Keyword(s):  
Gap Junction ◽  
Ventricular Myocytes ◽  
Critical Role ◽  
Mouse Heart ◽  
Wild Type ◽  
Short Term ◽  
Wild Type Littermate ◽  
Cx43 Expression ◽  
Significant Prolongation ◽  
Electrophysiological Effects

Gap junction redistribution and reduced expression, a phenomenon termed gap junction remodeling (GJR), is often seen in diseased hearts and may predispose toward arrhythmias. We have recently shown that short-term pacing in the mouse is associated with changes in connexin43 (Cx43) expression and localization but not with increased inducibility into sustained arrhythmias. We hypothesized that short-term pacing, if imposed on murine hearts with decreased Cx43 abundance, could serve as a model for evaluating the electrophysiological effects of GJR. We paced wild-type (normal Cx43 abundance) and heterozygous Cx43 knockout (Cx43+/−; 66% mean reduction in Cx43) mice for 6 h at 10–15% above their average sinus rate. We investigated the electrophysiological effects of pacing on the whole animal using programmed electrical stimulation and in isolated ventricular myocytes with patch-clamp studies. Cx43+/− myocytes had significantly shorter action potential durations (APD) and increased steady-state ( Iss) and inward rectifier ( IK1) potassium currents compared with those of wild-type littermate cells. In Cx43+/− hearts, pacing resulted in a significant prolongation of ventricular effective refractory period and APD and significant diminution of Iss compared with unpaced Cx43+/− hearts. However, these changes were not seen in paced wild-type mice. These data suggest that Cx43 abundance plays a critical role in regulating currents involved in myocardial repolarization and their response to pacing. Our study may aid in understanding how dyssynchronous activation of diseased, Cx43-deficient myocardial tissue can lead to electrophysiological changes, which may contribute to the worsened prognosis often associated with pacing in the failing heart.

scholarly journals The Role of Nrf2 in the Antioxidant Cellular Response to Medical Ozone Exposure

2019 ◽  
Vol 20 (16) ◽  
pp. 4009 ◽  
Author(s):  
Mirco Galiè ◽  
Viviana Covi ◽  
Gabriele Tabaracci ◽  
Manuela Malatesta
Keyword(s):  
Cellular Response ◽  
Tissue Injury ◽  
Scientific Evidence ◽  
Antioxidant Response ◽  
Ozone Exposure ◽  
Related Factor ◽  
Cellular Mechanisms ◽  
Medical Ozone ◽  
Living Organisms

Ozone (O3) is a natural, highly unstable atmospheric gas that rapidly decomposes to oxygen. Although not being a radical molecule, O3 is a very strong oxidant and therefore it is potentially toxic for living organisms. However, scientific evidence proved that the effects of O3 exposure are dose-dependent: high dosages stimulate severe oxidative stress resulting in inflammatory response and tissue injury, whereas low O3 concentrations induce a moderate oxidative eustress activating antioxidant pathways. These properties make O3 a powerful medical tool, which can be used as either a disinfectant or an adjuvant agent in the therapy of numerous diseases. In this paper, the cellular mechanisms involved in the antioxidant response to O3 exposure will be reviewed with special reference to the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its role in the efficacy of ozone therapy.

Critical Role of CIB1 in Endothelial Cell Function and In Vivo Ischemia-Induced Angiogenesis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1800-1800
Author(s):  
Mohamed A. Zayed ◽  
Andrew McFadden ◽  
Weiping Yuan ◽  
Mary E. Hartnett ◽  
Dan Chalothorn ◽  
...  
Keyword(s):  
Hind Limb ◽  
Ex Vivo ◽  
Critical Role ◽  
Tube Formation ◽  
Wild Type ◽  
Wild Type Littermate ◽  
Retinal Angiogenesis

Abstract CIB1, a 22kDa EF-hand containing calcium binding protein, was originally identified in a yeast two-hybrid screen as a binding partner for the cytoplasmic tail of the platelet integrin αIIb. CIB1 also associates with a number of kinases and modulates their activity, suggesting that CIB1 is an important regulatory molecule. Recently, we found that CIB1 is expressed in multiple endothelial cell (EC) types. We therefore tested the role of CIB1 in EC function in vitro, and in angiogenesis both ex vivo and in vivo. To test the role of CIB1 in EC function in vitro, we reduced endogenous CIB1 levels in ECs by RNA interference with an shRNA-delivered by lentivirus. CIB1 depletion significantly decreased EC haptotaxis on fibronectin and EC vascular tube formation on growth factor-reduced Matrigel. Treatment with FGF-2, an angiogenic factor, did not counter the observed inhibition of haptotaxis and tube formation by shRNA against CIB1. However, CIB1 overexpression enhanced FGF-2-induced EC haptotaxis relative to control cells. Similarly, ECs derived from CIB1 null mice exhibited a significant decrease in haptotaxis, tube formation, and proliferation compared to ECs isolated from wild-type littermate controls. In ex vivo aortic ring and tibialis anterior muscle culture assays, CIB1 null cultures supplemented with serum or FGF-2 demonstrated reduced blood vessel sprouting compared to wild-type littermate control cultures. Finally, in vivo assays for hyperoxic retinal angiogenesis and hind-limb induced-ischemia revealed a decrease in post-ischemia retinal neovascularization and Doppler hind-limb blood perfusion recovery, although developmental retinal angiogenesis in CIB1 null mice appeared normal. In conclusion, these findings support a critical role for CIB1 in EC function that appears to be important for ischemia-induced angiogenesis.

scholarly journals MTHFR-deficiency Increases Ischemic Damage Through Reduced Neuronal and Astrocytes Viability and Changes in the Cellular Response (P01-020-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Mahira Moftah ◽  
Greg Cron ◽  
Joshua Emmerson ◽  
Bill Willmore ◽  
Patrice Smith ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cell Viability ◽  
Motor Function ◽  
Cellular Response ◽  
Blue Staining ◽  
Primary Neurons ◽  
Wild Type ◽  
Increased Risk ◽  
Mthfr Deficiency

Abstract Objectives Stroke is a leading cause of disability and death world-wide. Increased levels of homocysteine are associated with risk for stroke. Metheylenetetrahydrofolate reductase (MTHFR) generates methyl groups to aid in the metabolism of homocysteine. A polymorphism in MTHFR (677C→T) has been identified in 5–15% of North American and European populations. Individuals with the TT genotype have elevated homocysteine concentrations and have increased risk of stroke. Using the MTHFR mouse model, the objective of this study was to investigate the mechanisms through which MTHFR deficiency may increase the risk of stroke. Methods We isolated primary neurons and astrocytes cells from MTHFR-deficient mice and exposed cells to hypoxia for 6 hours. Twenty-four hours after damage, we measured cell viability. In vivo, using aged (∼1.5-year-old) male Mthfr+/− and wildtype littermate controls, the sensorimotor cortex was damaged using the photothrombosis model to induce ischemic stroke. Post-operatively, animals were tested on skilled motor function, and brain tissue was processed for analysis. Additionally, in adult male mice using MRI we measured lesion volume two and four weeks after damage. Results Primary neurons and astrocytes from MTHFR-deficient embryos showed reduced cell viability through increased trypan blue staining and MTT release. In vivo, aged Mthfr+/− mice were impaired in skilled motor function after damage. Using MRI, adult Mthfr+/− brains were more severely damaged compared to wild-type littermates. In vitro and in vivo, we observed increased apoptosis in Mthfr+/− animals. Furthermore, methionine adenosyltransferase II alpha (MAT2A) protein levels were increased in the stroke hemisphere of wild-type mice. In the non-PT hemisphere of Mthfr+/− mice there was an increase in hypoxia induced factor 1 alpha (HIF-1α) protein and growth differentiation factor 11 (GDF11). Conclusions Together, our results suggest that Mthfr+/− mice are more vulnerable to ischemic stroke damage. This is through reducing neuronal and astrocyte viability after damage, as well as changes in methylation and cellular response. Funding Sources This research was funded by the Natural Sciences and Engineering Research Council, Council of Ontario Universities, and Fonds de la recherché en santé Québec (FRSQ).

scholarly journals The stress response protein REDD1 promotes diabetes-induced oxidative stress in the retina by Keap1-independent Nrf2 degradation

2020 ◽  
Vol 295 (21) ◽  
pp. 7350-7361 ◽  
Author(s):  
William P. Miller ◽  
Siddharth Sunilkumar ◽  
Joseph F. Giordano ◽  
Allyson L. Toro ◽  
Alistair J. Barber ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Glycogen Synthase ◽  
Critical Role ◽  
Antioxidant Response ◽  
Glycogen Synthase Kinase ◽  
Related Factor ◽  
Diabetic Mice ◽  
Antioxidant Genes ◽  
Deficient Mice

The transcription factor nuclear factor erythroid-2–related factor 2 (Nrf2) plays a critical role in reducing oxidative stress by promoting the expression of antioxidant genes. Both individuals with diabetes and preclinical diabetes models exhibit evidence of a defect in retinal Nrf2 activation. We recently demonstrated that increased expression of the stress response protein regulated in development and DNA damage 1 (REDD1) is necessary for the development of oxidative stress in the retina of streptozotocin-induced diabetic mice. In the present study, we tested the hypothesis that REDD1 suppresses the retinal antioxidant response to diabetes by repressing Nrf2 function. We found that REDD1 ablation enhances Nrf2 DNA-binding activity in the retina and that the suppressive effect of diabetes on Nrf2 activity is absent in the retina of REDD1-deficient mice compared with WT. In human MIO-M1 Müller cell cultures, REDD1 deletion prevented oxidative stress in response to hyperglycemic conditions, and this protective effect required Nrf2. REDD1 suppressed Nrf2 stability by promoting its proteasomal degradation independently of Nrf2's interaction with Kelch-like ECH-associated protein 1 (Keap1), but REDD1-mediated Nrf2 degradation required glycogen synthase kinase 3 (GSK3) activity and Ser-351/Ser-356 of Nrf2. Diabetes diminished inhibitory phosphorylation of glycogen synthase kinase 3β (GSK3β) at Ser-9 in the retina of WT mice but not in REDD1-deficient mice. Pharmacological inhibition of GSK3 enhanced Nrf2 activity and prevented oxidative stress in the retina of diabetic mice. The findings support a model wherein hyperglycemia-induced REDD1 blunts the Nrf2 antioxidant response to diabetes by activating GSK3, which, in turn, phosphorylates Nrf2 to promote its degradation.

scholarly journals Nrf2-ARE Signaling Partially Attenuates Lipopolysaccharide-Induced Mammary Lesions via Regulation of Oxidative and Organelle Stresses but Not Inflammatory Response in Mice

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yongxin Li ◽  
Juanjuan Shao ◽  
Pengfei Hou ◽  
Feng-Qi Zhao ◽  
Hongyun Liu
Keyword(s):  
Mammary Gland ◽  
Antioxidant Response ◽  
Mouse Mammary Gland ◽  
Related Factor ◽  
Wild Type ◽  
Lps Challenge ◽  
Multiple Organs ◽  
Milk Protein Genes ◽  
Nrf2 Knockout ◽  
Lps Treatment

The incidence of mastitis is high during the postpartum stage, which causes severe pain and hinders breast feeding in humans and reduces milk production in dairy cows. Studies suggested that inflammation in multiple organs is associated with oxidative stress and nuclear factor E2-related factor 2 (Nrf2)-antioxidant response element pathway is one of the most important antioxidant pathways, but the effects of Nrf2 on antioxidation in the mammary gland during mastitis are still unclear. In this study, intramammary lipopolysaccharide (LPS) challenge was carried out in wild-type (WT) and Nrf2 knockout mice. Results showed that the expression of Nrf2 affected the expression of milk protein genes (Csn2 and Csn3). Importantly, LPS treatment increased the expression of Nrf2 and HO-1 and the content of glutathione in the mammary gland of WT mice, but not in Nrf2(-/-) mice. The expression levels of glutathione synthesis genes (GCLC, GCLM, and xCT) were lower in Nrf2(-/-) mice than in WT mice. Moreover, mitochondrial-dependent apoptotic and endoplasmic reticulum stress were significantly relieved in WT mice compared with that in Nrf2(-/-) mice. In summary, the expression of Nrf2 may play an important role in prevention of oxidative and organelle stresses during endotoxin-induced mastitis in mouse mammary gland.

scholarly journals Oral Dimethyl Fumarate Reduces Peripheral Neuropathic Pain in Rodents via NFE2L2 Antioxidant Signaling

2020 ◽  
Vol 132 (2) ◽  
pp. 343-356 ◽  
Author(s):  
Jiahe Li ◽  
Jiacheng Ma ◽  
Michael J. Lacagnina ◽  
Sabina Lorca ◽  
Max A. Odem ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Neuropathic Pain ◽  
Nerve Injury ◽  
Dimethyl Fumarate ◽  
Antioxidant Response ◽  
Related Factor ◽  
Wild Type ◽  
Sprague Dawley ◽  
Male And Female ◽  
Stress Dependent

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Available treatments for neuropathic pain have modest efficacy and significant adverse effects, including abuse potential. Because oxidative stress is a key mechanistic node for neuropathic pain, the authors focused on the master regulator of the antioxidant response—nuclear factor erythroid 2-related factor 2 (NFE2L2; Nrf2)—as an alternative target for neuropathic pain. The authors tested whether dimethyl fumarate (U.S. Food and Drug Administration-approved treatment for multiple sclerosis) would activate NFE2L2 and promote antioxidant activity to reverse neuropathic pain behaviors and oxidative stress-dependent mechanisms. Methods Male Sprague Dawley rats, and male and female wild type and Nfe2l2-/- mice were treated with oral dimethyl fumarate/vehicle for 5 days (300 mg/kg; daily) after spared nerve injury/sham surgery (n = 5 to 8 per group). Allodynia was measured in von Frey reflex tests and hyperalgesia in operant conflict-avoidance tests. Ipsilateral L4/5 dorsal root ganglia were assayed for antioxidant and cytokine/chemokine levels, and mitochondrial bioenergetic capacity. Results Dimethyl fumarate treatment reversed mechanical allodynia (injury-vehicle, 0.45 ± 0.06 g [mean ± SD]; injury-dimethyl fumarate, 8.2 ± 0.16 g; P < 0.001) and hyperalgesia induced by nerve injury (injury-vehicle, 2 of 6 crossed noxious probes; injury-dimethyl fumarate, 6 of 6 crossed; P = 0.013). The antiallodynic effect of dimethyl fumarate was lost in nerve-injured Nfe2l2-/- mice, but retained in nerve-injured male and female wild type mice (wild type, 0.94 ± 0.25 g; Nfe2l2-/-, 0.02 ± 0.01 g; P < 0.001). Superoxide dismutase activity was increased by dimethyl fumarate after nerve injury (injury-vehicle, 3.96 ± 1.28 mU/mg; injury-dimethyl fumarate, 7.97 ± 0.47 mU/mg; P < 0.001). Treatment reduced the injury-dependent increases in cytokines and chemokines, including interleukin-1β (injury-vehicle, 13.30 ± 2.95 pg/mg; injury-dimethyl fumarate, 6.33 ± 1.97 pg/mg; P = 0.022). Injury-impaired mitochondrial bioenergetics, including basal respiratory capacity, were restored by dimethyl fumarate treatment (P = 0.025). Conclusions Dimethyl fumarate, a nonopioid and orally-bioavailable drug, alleviated nociceptive hypersensitivity induced by peripheral nerve injury via activation of NFE2L2 antioxidant signaling. Dimethyl fumarate also resolved neuroinflammation and mitochondrial dysfunction—oxidative stress-dependent mechanisms that drive nociceptive hypersensitivity after nerve injury.

scholarly journals Impaired F1Fo-ATP-Synthase Dimerization Leads to the Induction of Cyclophilin D-Mediated Autophagy-Dependent Cell Death and Accelerated Aging

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 757
Author(s):  
Verena Warnsmann ◽  
Lisa-Marie Marschall ◽  
Heinz D. Osiewacz
Keyword(s):  
Cell Death ◽  
Atp Synthase ◽  
Cellular Response ◽  
Critical Role ◽  
Specific Inhibitor ◽  
Cyclophilin D ◽  
Wild Type ◽  
Pronounced Increase ◽  
F1fo Atp Synthase ◽  
Dependent Cell

Mitochondrial F1Fo-ATP-synthase dimers play a critical role in shaping and maintenance of mitochondrial ultrastructure. Previous studies have revealed that ablation of the F1Fo-ATP-synthase assembly factor PaATPE of the ascomycete Podospora anserina strongly affects cristae formation, increases hydrogen peroxide levels, impairs mitochondrial function and leads to premature cell death. In the present study, we investigated the underlying mechanistic basis. Compared to the wild type, we observed a slight increase in non-selective and a pronounced increase in mitophagy, the selective vacuolar degradation of mitochondria. This effect depends on the availability of functional cyclophilin D (PaCYPD), the regulator of the mitochondrial permeability transition pore (mPTP). Simultaneous deletion of PaAtpe and PaAtg1, encoding a key component of the autophagy machinery or of PaCypD, led to a reduction of mitophagy and a partial restoration of the wild-type specific lifespan. The same effect was observed in the PaAtpe deletion strain after inhibition of PaCYPD by its specific inhibitor, cyclosporin A. Overall, our data identify autophagy-dependent cell death (ADCD) as part of the cellular response to impaired F1Fo-ATP-synthase dimerization, and emphasize the crucial role of functional mitochondria in aging.

scholarly journals The redox-sensitive transcription factor Nrf2 regulates murine hematopoietic stem cell survival independently of ROS levels

Blood ◽  
2011 ◽  
Vol 118 (25) ◽  
pp. 6572-6579 ◽  
Author(s):  
Akil A. Merchant ◽  
Anju Singh ◽  
William Matsui ◽  
Shyam Biswal
Keyword(s):  
Oxidative Stress ◽  
Stem Cell ◽  
Cell Survival ◽  
Cell Function ◽  
Critical Role ◽  
Antioxidant Response ◽  
Cytokine Signaling ◽  
Related Factor ◽  
Hematopoietic Stem ◽  
Stem Cell Survival

Abstract Several studies have found that high levels of reactive oxidative species (ROS) are associated with stem cell dysfunction. In the present study, we investigated the role of nuclear factor erythroid-2–related factor 2 (Nrf2), a master regulator of the antioxidant response, and found that it is required for hematopoietic stem progenitor cell (HSPC) survival and myeloid development. Although the loss of Nrf2 leads to increased ROS in most tissues, basal ROS levels in Nrf2-deficient (Nrf2−/−) BM were not elevated compared with wild-type. Nrf2−/− HSPCs, however, had increased rates of spontaneous apoptosis and showed decreased survival when exposed to oxidative stress. Nrf2−/− BM demonstrated defective stem cell function, as evidenced by reduced chimerism after transplantation that was not rescued by treatment with the antioxidant N-acetyl cysteine. Gene-expression profiling revealed that the levels of prosurvival cytokines were reduced in Nrf2−/− HSPCs. Treatment with the cytokine G-CSF improved HSPC survival after exposure to oxidative stress and rescued the transplantation defect in Nrf2−/− cells despite increases in ROS induced by cytokine signaling. These findings demonstrate a critical role for Nrf2 in hematopoiesis and stem cell survival that is independent of ROS levels.

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