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p62 deficiency induces oxidative stress and senescence in vivo and in vitro in VSMCs
S126
A. Newman / Free Radical Biology and Medicine 128 (2018) S123–S129
stomach of KO mice and hope to elucidate the role of Trx1 in development of cellular identity in this highly proliferative tissue.
https://doi.org/10.1016/j.freeradbiomed.2018.10.309
301
Aerobic exercise in older adults maintains Nrf2 signaling compared to inactive controls Ethan Ostrom*, Nadja Jones, Savannah Berry, Ciara Terry, Tinna Traustadottir Northern Arizona University, USA
We have previously shown that older men have impaired Nrf2 signaling response to acute exercise as compared to young controls. The present RCT investigated whether exercise-induced Nrf2 signaling would improve with a more regular exercise stimulus. Inactive men and women (62-77y) were randomized to an 8-week exercise intervention (EX, n¼ 9) or a non-exercise control group (CON, n¼8). EX performed supervised aerobic exercise 3d/wk for 45-min/d. The effectiveness of the exercise intervention was measured by changes in maximal aerobic capacity (VO2max). Nrf2 signaling was measured in response to acute exercise (30-min cycling at 70% VO2max) in isolated PBMCs. Nrf2 protein quantification was measured at 7 time points (Pre, þ10, þ30, þ 1, þ 4, þ8, þ24h) and gene expression of HO-1, NQO1, and GCLC were measured at 5 time points (Pre, þ 1, þ4, þ8, and þ24h) before and after the 8-week intervention. There were no significant differences between sexes for any variable or baseline differences between EX and CON. The exercise intervention improved VO2max by 19% (po0.05) while CON did not change. The acute exercise trial significantly increased Nrf2 nuclear expression in both groups (po0.05). The response did not change in EX pre-post intervention, however CON had an attenuated response at post-testing (po0.05). Interestingly, basal levels of nuclear Nrf2 were 3-fold greater post-intervention compared to pre in both groups (po0.05). The intervention had a significant effect on NQO1 gene expression (po0.05) which mirrored the Nrf2 response: maintained in EX and attenuated in CON. There were no significant effects for HO-1 and GCLC. These preliminary results indicate that an 8-week exercise intervention is not sufficient to increase exercise-induced Nrf2 signaling, despite improving aerobic fitness. Nevertheless, the magnitude of the response after exercise training was more robust than observed in the inactive controls. Additional testing and analyses, including young individuals, are underway.
https://doi.org/10.1016/j.freeradbiomed.2018.10.310
302
The novel mitochondria-targeted hydrogen sulfide donors AP39 and AP123 exert anti-photoaging effects on primary dermal fibroblasts and mouse skin exposed to UVA in association with activation of Nrf2-mediated antioxidant response Uraiwan Panich 1,*, Jinapath Lohakul 1, Matthew Whiteman 2 1 2
Mahidol University, Thailand University of Exeter Medical School, United Kingdom
Ultraviolet A (UVA) radiation plays a role in photodamaged skin through stimulating oxidative stress-induced various matrix metalloproteases (including MMP-1, 3 and 9) leading to degradation of extracellular matrix
proteins, in particular, collagen, which are the hallmark of skin aging. Compromised mitochondrial integrity mediated by ROS is also responsible for cellular damage and dysfunction of the skin. Thus, promoting activity of nuclear factor E2-related factor 2 (Nrf2), a transcription factor controlling the antioxidant response, represents a promising strategy for inhibiting photoaging. We aimed to assess whether mitochondria-targeted hydrogen sulfide (H2S) donors (AP39 and AP123), having abilities to suppress mitochondrial ROS, exerted anti-photoaging effects via activating Nrf2 in dermal fibroblasts and mouse skin exposed to UVA. At first, AP39 and AP123 were shown to inhibit UVA (8 J/cm2)-mediated induction of ROS formation and MMP-1 activity as well as reduction of collagen in primary dermal fibroblasts. Then, we determined anti-photoaging effects of AP39 and AP123 on MMP-1, 3 and 9, collagen, MnSOD and PGC-1α (peroxisome proliferator-activated receptor γ, coactivator 1α; co-transcriptional regulation factor controlling mitochondrial biogenesis) in association with Nrf2 nuclear localization in BALB/c mouse skin exposed to UVA (60 J/cm2). Our finding revealed that topical treatment with AP39 or AP123 dose-dependently protected against UVA-mediated increased MMP-1, 3 and 9 expression and decreased collagen levels as compared to the vehicle-treated group. In addition, both compounds could reverse UVA-dependent reduction of MnSOD and PGC-1α expressions. Application of AP39 and AP123 to mouse skin prior to UVA exposure was also shown to increase Nrf2 nuclear translocation and reduce oxidative DNA damage formation (8-hydroxy-2'deoxyguanosine; 8-OHdG). In summary, AP39 and AP123 capable of activating Nrf2 and promoting mitochondrial integrity could provide antiphotoaging effects on dermal fibroblasts and mouse skin through suppression of UVA-mediated induction of MMPs and reduction of collagen.
https://doi.org/10.1016/j.freeradbiomed.2018.10.311
303
SQSTM1/p62 deficiency induces oxidative stress and senescence in vivo and in vitro in VSMCs Gloria Salazar*, Jingwen Huang, Yitong Zhao Florida State University, USA
Aging is a major contributor to age-related diseases including cardiovascular disease (CVD). Vascular senescence, a hallmark of mammalian aging, has been linked to vascular disease like atherosclerosis. We previously showed that the NADPH oxidase Nox1 mediates senescence induced by angiotensin II, a major inducer of vascular aging and CVD. Disruption of other processes, like autophagy, also promotes senescence due to the accumulation of dysfunctional mitochondria leading to upregulation of ROS levels. SQSTM1, known as p62, is an autophagy adaptor involved in the targeting of protein aggregates and dysfunctional organelles, including mitochondria, into the autophagy degradation pathway. The interaction between NADPH oxidases and autophagy in the senescence pathway is incompletely understood. Using vascular smooth muscle cells (VSMCs) isolated from aortas of p62 þ / þ and p62-/- mice, we found that lack of p62 causes senescence by a ROS-dependent and Nox1-independent mechanism. Downregulation of p62 decreased cell proliferation, increased the expression of the senescence markers (senescence associated-β-galactosidase (SA-β-gal) and p21) and increased superoxide, hydrogen peroxide and mitochondrial ROS levels. Treatment with the antioxidant N-acetyl cysteine (NAC) and the mitochondrial ROS scavenger MitoTEMPO reduced SA-β-gal activity in p62-/- VSMCs, suggesting that cytosolic ROS, as well as mitochondrial ROS contribute to the development of senescence. These effects were not associated with upregulation of Nox1. Further, senescence was also upregulated in vivo in aortas of male and female p62-/-, compared with p62 þ / þ mice. Altogether, these data suggest lack of p62 induces oxidative stress by a Nox1-independent and mitochondrial-dependent mechanisms.
https://doi.org/10.1016/j.freeradbiomed.2018.10.312
A. Newman / Free Radical Biology and Medicine 128 (2018) S123–S129
stomach of KO mice and hope to elucidate the role of Trx1 in development of cellular identity in this highly proliferative tissue.
https://doi.org/10.1016/j.freeradbiomed.2018.10.309
301
Aerobic exercise in older adults maintains Nrf2 signaling compared to inactive controls Ethan Ostrom*, Nadja Jones, Savannah Berry, Ciara Terry, Tinna Traustadottir Northern Arizona University, USA
We have previously shown that older men have impaired Nrf2 signaling response to acute exercise as compared to young controls. The present RCT investigated whether exercise-induced Nrf2 signaling would improve with a more regular exercise stimulus. Inactive men and women (62-77y) were randomized to an 8-week exercise intervention (EX, n¼ 9) or a non-exercise control group (CON, n¼8). EX performed supervised aerobic exercise 3d/wk for 45-min/d. The effectiveness of the exercise intervention was measured by changes in maximal aerobic capacity (VO2max). Nrf2 signaling was measured in response to acute exercise (30-min cycling at 70% VO2max) in isolated PBMCs. Nrf2 protein quantification was measured at 7 time points (Pre, þ10, þ30, þ 1, þ 4, þ8, þ24h) and gene expression of HO-1, NQO1, and GCLC were measured at 5 time points (Pre, þ 1, þ4, þ8, and þ24h) before and after the 8-week intervention. There were no significant differences between sexes for any variable or baseline differences between EX and CON. The exercise intervention improved VO2max by 19% (po0.05) while CON did not change. The acute exercise trial significantly increased Nrf2 nuclear expression in both groups (po0.05). The response did not change in EX pre-post intervention, however CON had an attenuated response at post-testing (po0.05). Interestingly, basal levels of nuclear Nrf2 were 3-fold greater post-intervention compared to pre in both groups (po0.05). The intervention had a significant effect on NQO1 gene expression (po0.05) which mirrored the Nrf2 response: maintained in EX and attenuated in CON. There were no significant effects for HO-1 and GCLC. These preliminary results indicate that an 8-week exercise intervention is not sufficient to increase exercise-induced Nrf2 signaling, despite improving aerobic fitness. Nevertheless, the magnitude of the response after exercise training was more robust than observed in the inactive controls. Additional testing and analyses, including young individuals, are underway.
https://doi.org/10.1016/j.freeradbiomed.2018.10.310
302
The novel mitochondria-targeted hydrogen sulfide donors AP39 and AP123 exert anti-photoaging effects on primary dermal fibroblasts and mouse skin exposed to UVA in association with activation of Nrf2-mediated antioxidant response Uraiwan Panich 1,*, Jinapath Lohakul 1, Matthew Whiteman 2 1 2
Mahidol University, Thailand University of Exeter Medical School, United Kingdom
Ultraviolet A (UVA) radiation plays a role in photodamaged skin through stimulating oxidative stress-induced various matrix metalloproteases (including MMP-1, 3 and 9) leading to degradation of extracellular matrix
proteins, in particular, collagen, which are the hallmark of skin aging. Compromised mitochondrial integrity mediated by ROS is also responsible for cellular damage and dysfunction of the skin. Thus, promoting activity of nuclear factor E2-related factor 2 (Nrf2), a transcription factor controlling the antioxidant response, represents a promising strategy for inhibiting photoaging. We aimed to assess whether mitochondria-targeted hydrogen sulfide (H2S) donors (AP39 and AP123), having abilities to suppress mitochondrial ROS, exerted anti-photoaging effects via activating Nrf2 in dermal fibroblasts and mouse skin exposed to UVA. At first, AP39 and AP123 were shown to inhibit UVA (8 J/cm2)-mediated induction of ROS formation and MMP-1 activity as well as reduction of collagen in primary dermal fibroblasts. Then, we determined anti-photoaging effects of AP39 and AP123 on MMP-1, 3 and 9, collagen, MnSOD and PGC-1α (peroxisome proliferator-activated receptor γ, coactivator 1α; co-transcriptional regulation factor controlling mitochondrial biogenesis) in association with Nrf2 nuclear localization in BALB/c mouse skin exposed to UVA (60 J/cm2). Our finding revealed that topical treatment with AP39 or AP123 dose-dependently protected against UVA-mediated increased MMP-1, 3 and 9 expression and decreased collagen levels as compared to the vehicle-treated group. In addition, both compounds could reverse UVA-dependent reduction of MnSOD and PGC-1α expressions. Application of AP39 and AP123 to mouse skin prior to UVA exposure was also shown to increase Nrf2 nuclear translocation and reduce oxidative DNA damage formation (8-hydroxy-2'deoxyguanosine; 8-OHdG). In summary, AP39 and AP123 capable of activating Nrf2 and promoting mitochondrial integrity could provide antiphotoaging effects on dermal fibroblasts and mouse skin through suppression of UVA-mediated induction of MMPs and reduction of collagen.
https://doi.org/10.1016/j.freeradbiomed.2018.10.311
303
SQSTM1/p62 deficiency induces oxidative stress and senescence in vivo and in vitro in VSMCs Gloria Salazar*, Jingwen Huang, Yitong Zhao Florida State University, USA
Aging is a major contributor to age-related diseases including cardiovascular disease (CVD). Vascular senescence, a hallmark of mammalian aging, has been linked to vascular disease like atherosclerosis. We previously showed that the NADPH oxidase Nox1 mediates senescence induced by angiotensin II, a major inducer of vascular aging and CVD. Disruption of other processes, like autophagy, also promotes senescence due to the accumulation of dysfunctional mitochondria leading to upregulation of ROS levels. SQSTM1, known as p62, is an autophagy adaptor involved in the targeting of protein aggregates and dysfunctional organelles, including mitochondria, into the autophagy degradation pathway. The interaction between NADPH oxidases and autophagy in the senescence pathway is incompletely understood. Using vascular smooth muscle cells (VSMCs) isolated from aortas of p62 þ / þ and p62-/- mice, we found that lack of p62 causes senescence by a ROS-dependent and Nox1-independent mechanism. Downregulation of p62 decreased cell proliferation, increased the expression of the senescence markers (senescence associated-β-galactosidase (SA-β-gal) and p21) and increased superoxide, hydrogen peroxide and mitochondrial ROS levels. Treatment with the antioxidant N-acetyl cysteine (NAC) and the mitochondrial ROS scavenger MitoTEMPO reduced SA-β-gal activity in p62-/- VSMCs, suggesting that cytosolic ROS, as well as mitochondrial ROS contribute to the development of senescence. These effects were not associated with upregulation of Nox1. Further, senescence was also upregulated in vivo in aortas of male and female p62-/-, compared with p62 þ / þ mice. Altogether, these data suggest lack of p62 induces oxidative stress by a Nox1-independent and mitochondrial-dependent mechanisms.
https://doi.org/10.1016/j.freeradbiomed.2018.10.312