Modulation of signaling mechanisms in the heart by thioredoxin 1

Nagarajan, Narayani; Oka, Shinichi; Sadoshima, Junichi

doi:10.1016/j.freeradbiomed.2016.12.020

Cited by 60 publications

(43 citation statements)

References 71 publications

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“…To further confirm these findings in intact cells, we isolated cardiomyocytes from WT and HAXiKO hearts and infected them with an adenovirus encoding thioredoxin 1 (Trx1) to inhibit cysteine modification [44]. There were no effects of Trx1 on SERCA2a levels under basal conditions.…”

Section: Resultsmentioning

confidence: 99%

HAX-1 regulates SERCA2a oxidation and degradation

Bidwell

Liu

Nagarajan

et al. 2018

Journal of Molecular and Cellular Cardiology

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Ischemia/reperfusion injury is associated with contractile dysfunction and increased cardiomyocyte death. Overexpression of the hematopoietic lineage substrate-1-associated protein X-1 (HAX-1) has been shown to protect from cellular injury but the function of endogenous HAX-1 remains obscure due to early lethality of the knockout mouse. Herein we generated a cardiac-specific and inducible HAX-1 deficient model, which uncovered an unexpected role of HAX-1 in regulation of sarco/endoplasmic reticulum Ca-ATPase (SERCA2a) in ischemia/reperfusion injury. Although ablation of HAX-1 in the adult heart elicited no morphological alterations under non-stress conditions, it diminished contractile recovery and increased infarct size upon ischemia/reperfusion injury. These detrimental effects were associated with increased loss of SERCA2a. Enhanced SERCA2a degradation was not due to alterations in calpain and calpastatin levels or calpain activity. Conversely, HAX-1 overexpression improved contractile recovery and maintained SERCA2a levels. The regulatory effects of HAX-1 on SERCA2a degradation were observed at multiple levels, including intact hearts, isolated cardiomyocytes and sarcoplasmic reticulum microsomes. Mechanistically, HAX-1 ablation elicited increased production of reactive oxygen species at the sarco/endoplasic reticulum compartment, resulting in SERCA2a oxidation and a predisposition to its proteolysis. This effect may be mediated by NAPDH oxidase 4 (NOX4), a novel binding partner of HAX-1. Accordingly, NOX inhibition with apocynin abrogated the effects of HAX-1 ablation in hearts subjected to ischemia/reperfusion injury. Taken together, our findings reveal a role of HAX-1 in the regulation of oxidative stress and SERCA2a degradation, implicating its importance in calcium homeostasis and cell survival pathways.

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Section: Resultsmentioning

confidence: 99%

HAX-1 regulates SERCA2a oxidation and degradation

Bidwell

Liu

Nagarajan

et al. 2018

Journal of Molecular and Cellular Cardiology

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“…Reactive oxygen species (ROS), 3 such as hydrogen peroxide (H 2 O 2 ), are generated by various biological reactions, including mitochondrial respiration and activation of ROS-producing enzymes such as NADPH oxidases. Increased ROS are frequently observed under various pathological and stressed conditions and are generally considered to promote the pathology because of oxidative damage of proteins, lipids, and DNAs.…”

Section: The Mtor Oxidation Was Accompanied By Reduced Phosphorylatiomentioning

confidence: 99%

“…Trx1 protects against oxidative stress (2). The cytoprotective effect of Trx1 renders resistance to ischemic injury in cardiomyocytes (3,4) and drug resistance in cancer cells (5). Although Trx1 itself does not react effectively with H 2 O 2 , Trx1 reduces H 2 O 2 through peroxiredoxins, Trx1-dependent peroxidases (6).…”

Section: The Mtor Oxidation Was Accompanied By Reduced Phosphorylatiomentioning

confidence: 99%

Thioredoxin-1 maintains mechanistic target of rapamycin (mTOR) function during oxidative stress in cardiomyocytes

Oka

Hirata

Suzuki

et al. 2017

Journal of Biological Chemistry

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Thioredoxin 1 (Trx1) is a 12-kDa oxidoreductase that catalyzes thiol-disulfide exchange reactions to reduce proteins with disulfide bonds. As such, Trx1 helps protect the heart against stresses, such as ischemia and pressure overload. Mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that regulates cell growth, metabolism, and survival. We have shown previously that mTOR activity is increased in response to myocardial ischemia-reperfusion injury. However, whether Trx1 interacts with mTOR to preserve heart function remains unknown. Using a substrate-trapping mutant of Trx1 (Trx1C35S), we show here that mTOR is a direct interacting partner of Trx1 in the heart. In response to HO treatment in cardiomyocytes, mTOR exhibited a high molecular weight shift in non-reducing SDS-PAGE in a 2-mercaptoethanol-sensitive manner, suggesting that mTOR is oxidized and forms disulfide bonds with itself or other proteins. The mTOR oxidation was accompanied by reduced phosphorylation of endogenous substrates, such as S6 kinase (S6K) and 4E-binding protein 1 (4E-BP1) in cardiomyocytes. Immune complex kinase assays disclosed that HO treatment diminished mTOR kinase activity, indicating that mTOR is inhibited by oxidation. Of note, Trx1 overexpression attenuated both HO-mediated mTOR oxidation and inhibition, whereas Trx1 knockdown increased mTOR oxidation and inhibition. Moreover, Trx1 normalized HO-induced down-regulation of metabolic genes and stimulation of cell death, and an mTOR inhibitor abolished Trx1-mediated rescue of gene expression. HO-induced oxidation and inhibition of mTOR were attenuated when Cys-1483 of mTOR was mutated to phenylalanine. These results suggest that Trx1 protects cardiomyocytes against stress by reducing mTOR at Cys-1483, thereby preserving the activity of mTOR and inhibiting cell death.

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“…Furthermore, similar to the methylglyoxal effect, hyperosmotic stress was also responsible for lower Trx1 protein. Trx participates in cellular redox homeostasis and antioxidant protection [21, 48]. Peroxiredoxins are important peroxidases that depend on Trx to be regenerated in the catalytic cycle [22, 49].…”

Section: Discussionmentioning

confidence: 99%

Hyperosmotic Stress Initiates AMPK-Independent Autophagy and AMPK- and Autophagy-Independent Depletion of Thioredoxin 1 and Glyoxalase 2 in HT22 Nerve Cells

Dafre

Schmitz

Maher

2019

Oxidative Medicine and Cellular Longevity

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Background. Hyperosmotic stress is an important pathophysiologic condition in diabetes, severe trauma, dehydration, infection, and ischemia. Furthermore, brain neuronal cells face hyperosmotic stress in ageing and Alzheimer’s disease. Despite the enormous importance of knowing the homeostatic mechanisms underlying the responses of nerve cells to hyperosmotic stress, this topic has been underrepresented in the literature. Recent evidence points to autophagy induction as a hallmark of hyperosmotic stress, which has been proposed to be controlled by mTOR inhibition as a consequence of AMPK activation. We previously showed that methylglyoxal induced a decrease in the antioxidant proteins thioredoxin 1 (Trx1) and glyoxalase 2 (Glo2), which was mediated by AMPK-dependent autophagy. Thus, we hypothesized that hyperosmotic stress would have the same effect. Methods. HT22 hippocampal nerve cells were treated with NaCl (37, 75, or 150 mM), and the activation of the AMPK/mTOR pathway was investigated, as well as the levels of Trx1 and Glo2. To determine if autophagy was involved, the inhibitors bafilomycin (Baf) and chloroquine (CQ), as well as ATG5 siRNA, were used. To test for AMPK involvement, AMPK-deficient mouse embryonic fibroblasts (MEFs) were used. Results. Hyperosmotic stress induced a clear increase in autophagy, which was demonstrated by a decrease in p62 and an increase in LC3 lipidation. AMPK phosphorylation, linked to a decrease in mTOR and S6 ribosomal protein phosphorylation, was also observed. Deletion of AMPK in MEFs did not prevent autophagy induction by hyperosmotic stress, as detected by decreased p62 and increased LC3 II, or mTOR inhibition, inferred by decreased phosphorylation of P70 S6 kinase and S6 ribosomal protein. These data indicating that AMPK was not involved in autophagy activation by hyperosmotic stress were supported by a decrease in pS555-ULK1, an AMPK phosphorylation site. Trx1 and Glo2 levels were decreased at 6 and 18 h after treatment with 150 mM NaCl. However, this decrease in Trx1 and Glo2 in HT22 cells was not prevented by autophagy inhibition by Baf, CQ, or ATG5 siRNA. AMPK-deficient MEFs under hyperosmotic stress presented the same Trx1 and Glo2 decrease as wild-type cells. Conclusion. Hyperosmotic stress induced AMPK activation, but this was not responsible for its effects on mTOR activity or autophagy induction. Moreover, the decrease in Trx1 and Glo2 induced by hyperosmotic stress was independent of both autophagy and AMPK activation.

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Modulation of signaling mechanisms in the heart by thioredoxin 1

Cited by 60 publications

References 71 publications

HAX-1 regulates SERCA2a oxidation and degradation

HAX-1 regulates SERCA2a oxidation and degradation

Thioredoxin-1 maintains mechanistic target of rapamycin (mTOR) function during oxidative stress in cardiomyocytes

Hyperosmotic Stress Initiates AMPK-Independent Autophagy and AMPK- and Autophagy-Independent Depletion of Thioredoxin 1 and Glyoxalase 2 in HT22 Nerve Cells

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