Polyphenols by Generating H2O2, Affect Cell Redox Signaling, Inhibit PTPs and Activate Nrf2 Axis for Adaptation and Cell Surviving: In Vitro, In Vivo and Human Health

Human health benefits from different polyphenols molecules consumption in the diet, derived mainly by their common activities in the gastrointestinal tract and at the level of blood micro-capillary. In the stomach, intestine and colon, polyphenols act as reducing agents preventing lipid peroxidation, generation and absorption of AGEs/ALEs (advanced glycation end products/advanced lipid oxidation end products) and postprandial oxidative stress. The low absorption of polyphenols in blood does not support their activity as antioxidants and their mechanism of activity is not fully understood. The results are from in vitro, animal and human studies, detected by relevant oxidative stress markers. The review carries evidences that polyphenols, by generating H2O2 at nM concentration, exogenous to cells and organs, act as activators of signaling factors increasing cell Eustress. When polyphenols attain high concentration in the blood system, they generate H2O2 at µM concentration, acting as cytotoxic agents and Distress. Pre-treatment of cells or organisms with polyphenols, by generating H2O2 at low levels, inhibits cellular PTPs (protein tyrosine phosphatases), inducing cell signaling through transcription of the Nrf2 (nuclear factor erythroid 2-related factor 2) axis of adaptation and protection to oxidation stress. Polyphenols ingestion at the right amount and time during the meal acts synergistically at the level of the gastrointestinal tract (GIT) and blood system, for keeping the redox homeostasis in our organism and better balancing human health.

Download Full-text

In vitro–In vivo Hybrid Approach for Studying Modulation of NRF2 in Immortalized Bovine Mammary Cells

Frontiers in Animal Science ◽

10.3389/fanim.2021.674355 ◽

2021 ◽

Vol 2 ◽

Author(s):

Hunter R. Ford ◽

Sebastiano Busato ◽

Massimo Bionaz

Keyword(s):

Oxidative Stress ◽

Blood Serum ◽

Hybrid Approach ◽

Related Factor ◽

Mammary Cells ◽

High Concentration ◽

Gene Reporter Assay ◽

Synthetic Media

Nuclear factor erythroid 2-related factor 2 (NRF2) plays a key role in the response to oxidative stress. Diets containing known NRF2 modulators could be used to minimize oxidative stress in dairy cows. Currently, studies evaluating the activity of NRF2 in bovine have used the classical in vitro approach using synthetic media, which is very different than in vivo conditions. Furthermore, studies carried out in vivo cannot capture the short-term and dynamic response of NRF2. Thus, there is a need to develop new approaches to study NRF2 modulation. The aim of the present study was to establish an in vitro–in vivo hybrid system to investigate activation of NRF2 in bovine cells that can serve as an intermediate model with results closer to what is expected in vivo. To accomplish the aim, we used a combination of a gene reporter assay in immortalized bovine mammary cells, synthetic NRF2 modulators, and blood serum from periparturient cows. Synthetic agonist tert-butylhydroquinone and sulforaphane confirmed to be effective activators of bovine NRF2 with acute and large effect at 30 and 5 μM, respectively, with null response after the above doses due to cytotoxicity. When the agonists were added to blood serum the response was more linear with maximum activation of NRF2 at 100 and 30 μM, respectively, and the cytotoxicity was prevented. High concentration of albumin in blood serum plays an important role in such an effect. Brusatol (100 nM) was observed to be an effective NRF2 inhibitor while also displaying general protein synthesis inhibition and cytotoxicity when added to synthetic media. A consistent inhibition of NRF2 was observed when brusatol was added to the blood serum but the cytotoxicity was reduced. The synthetic inhibitor ML385 had no effect on modulation of bovine NRF2. Hydrogen peroxide activates NRF2 in bovine mammary cells starting from 100 μM; however, strong cytotoxicity was detected starting at 250 μM when cells were cultivated in the synthetic media, while blood serum prevented cytotoxicity. Overall, our data indicated that the use of synthetic media can be misleading in the study of NRF2 in bovine and the use of blood serum appears necessary.

Download Full-text

Puerarin inhibits the retinal pericyte apoptosis induced by advanced glycation end products in vitro and in vivo by inhibiting NADPH oxidase-related oxidative stress

Free Radical Biology and Medicine ◽

10.1016/j.freeradbiomed.2012.04.030 ◽

2012 ◽

Vol 53 (2) ◽

pp. 357-365 ◽

Cited By ~ 54

Author(s):

Junghyun Kim ◽

Ki Mo Kim ◽

Chan-Sik Kim ◽

Eunjin Sohn ◽

Yun Mi Lee ◽

...

Keyword(s):

Oxidative Stress ◽

Nadph Oxidase ◽

Advanced Glycation End Products ◽

Advanced Glycation ◽

Glycation End Products ◽

End Products

Download Full-text

Antioxidant Effect of the Castanea sativa Mill. Leaf Extract on Oxidative Stress Induced upon Human Spermatozoa

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/8926075 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Marco Biagi ◽

Daria Noto ◽

Maddalena Corsini ◽

Giulia Baini ◽

Daniela Cerretani ◽

...

Keyword(s):

Oxidative Stress ◽

Antioxidant Activity ◽

Sperm Motility ◽

Leaf Extract ◽

Colorimetric Assay ◽

Castanea Sativa ◽

High Concentration ◽

Tem Analysis ◽

Dpph Test

This study was aimed at evaluating in vitro the effects of a 75% v/v ethanolic extract of leaves of Castanea sativa Mill. (var. Bastarda Rossa, Mount Amiata, Tuscany, Italy) on ejaculated human sperm. Total polyphenols and total flavonoids contained in the extract were determined by a colorimetric assay and HPLC-DAD. The DPPH test and electrochemistry were utilized to study the antioxidant activity of the extract. Swim-up-selected sperm from 8 healthy men were treated with the C. sativa leaf extract at different dilutions (1 : 100, 1 : 200, and 1 : 500), and sperm motility was assessed following the WHO guidelines. Swim-up-selected spermatozoa were incubated with 100 μM H2O2 to induce lipid peroxidation (LPO) and with H2O2 and the leaf extract (1 : 100, 1 : 200, and 1 : 500) to test the antioxidant activity of the extract. The levels of LPO were determined by measuring malondialdehyde (MDA) concentrations. The treated samples were also analyzed by transmission electron microscopy (TEM) for ultrastructural evaluation. The chemical analysis showed that one-third ca. of the polyphenols in the C. sativa extract were made up of flavonoids, with hyperoside present in high concentration. A good antioxidant activity was demonstrated by both the DPPH test and electrochemical analysis. The C. sativa leaf extract did not decrease sperm motility at all tested dilutions. Treatment with H2O2 alone caused a significant increment in MDA levels (P=0.006993), while the treatment with H2O2 plus C. sativa extract diluted to 1 : 100 and 1 : 200 significantly reduced MDA levels (P=0.01476 and P=0.01571, respectively), with respect to H2O2 alone. TEM analysis confirmed the protective effect of the extract on damage induced by LPO, in particular that occurring at the plasma membrane level. The C. sativa leaf extract could be used in human and farm animal protocols for gamete handling, such as techniques of assisted reproduction and cryopreservation of semen, all conditions in which oxidative stress is exacerbated.

Download Full-text

Ganoderic Acid D Protects Human Amniotic Mesenchymal Stem Cells against Oxidative Stress-Induced Senescence through the PERK/NRF2 Signaling Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/8291413 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Yan Xu ◽

Huan Yuan ◽

Yi Luo ◽

Yu-Jie Zhao ◽

Jian-Hui Xiao

Keyword(s):

Oxidative Stress ◽

Stem Cells ◽

Signaling Pathway ◽

Adult Stem Cells ◽

Telomerase Activity ◽

Related Factor ◽

Dependent Manner ◽

Ganoderic Acid ◽

Nrf2 Signaling Pathway

Aging is an important risk factor in the occurrence of many chronic diseases. Senescence and exhaustion of adult stem cells are considered as a hallmark of aging in organisms. In this study, a senescent human amniotic mesenchymal stem cell (hAMSC) model subjected to oxidative stress was established in vitro using hydrogen peroxide. We investigated the effects of ganoderic acid D (GA-D), a natural triterpenoid compound produced from Ganoderma lucidum, on hAMSC senescence. GA-D significantly inhibited β-galactosidase (a senescence-associated marker) formation, in a dose-dependent manner, with doses ranging from 0.1 μM to 10 μM, without inducing cytotoxic side-effects. Furthermore, GA-D markedly inhibited the generation of reactive oxygen species (ROS) and the expression of p21 and p16 proteins, relieved the cell cycle arrest, and enhanced telomerase activity in senescent hAMSCs. Furthermore, GA-D upregulated the expression of phosphorylated protein kinase R- (PKR-) like endoplasmic reticulum kinase (PERK), peroxidase III (PRDX3), and nuclear factor-erythroid 2-related factor (NRF2) and promoted intranuclear transfer of NRF2 in senescent cells. The PERK inhibitor GSK2656157 and/or the NRF2 inhibitor ML385 suppressed the PERK/NRF2 signaling, which was activated by GA-D. They induced a rebound for the generation of ROS and β-galactosidase-positive cells and attenuated the differentiation capacity. These findings suggest that GA-D retards hAMSC senescence through activation of the PERK/NRF2 signaling pathway and may be a promising candidate for the discovery of antiaging agents.

Download Full-text

Cpt1a promoted ROS-induced oxidative stress and inflammation in liver injury via the Nrf2/HO-1 and NLRP3 inflammasome signaling pathway

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2020-0165 ◽

2020 ◽

Author(s):

Xigang Luo ◽

Dapeng Sun ◽

Yinxiang Wang ◽

Fengxiang Zhang ◽

Yi Wang

Keyword(s):

Oxidative Stress ◽

Liver Injury ◽

Signaling Pathway ◽

Nlrp3 Inflammasome ◽

Receptor Protein ◽

Heme Oxygenase 1 ◽

Related Factor ◽

Over Expression ◽

Vitro Model

Various liver diseases caused by liver damage seriously affect people’s health. The purpose of this study was to clarify that the effects and mechanism of Carnitine palmitoyltransferase 1 (Cpt1a) on oxidative stress and inflammation in liver injury. It was found that the expression of Cpt1a mRNA was up-regulated in model mice of liver injury. So, over-expression of Cpt1a increased reactive oxygen species (ROS) production and malondialdehyde (MDA) levels, and reduced superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-px) levels in vitro model of liver injury. It was also shown that over-expression of Cpt1a suppressed the Nuclear factor-erythroid-2-related factor 2 (Nrf2)/ heme oxygenase-1 (HO-1) signaling pathway. In summary, these data indicate that Cpt1a promotes ROS-induced oxidative stress in liver injury via the Nrf2/HO-1 and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome signaling pathway.

Download Full-text

α1-Microglobulin (A1M) Protects Human Proximal Tubule Epithelial Cells from Heme-Induced Damage In Vitro

International Journal of Molecular Sciences ◽

10.3390/ijms21165825 ◽

2020 ◽

Vol 21 (16) ◽

pp. 5825 ◽

Cited By ~ 2

Author(s):

Amanda Kristiansson ◽

Sara Davidsson ◽

Maria E. Johansson ◽

Sarah Piel ◽

Eskil Elmér ◽

...

Keyword(s):

Oxidative Stress ◽

Epithelial Cells ◽

Proximal Tubule ◽

Mitochondrial Function ◽

Radical Scavenging ◽

Related Factor ◽

Protective Effects ◽

Cellular Expression ◽

Human Proximal Tubule

Oxidative stress is associated with many renal disorders, both acute and chronic, and has also been described to contribute to the disease progression. Therefore, oxidative stress is a potential therapeutic target. The human antioxidant α1-microglobulin (A1M) is a plasma and tissue protein with heme-binding, radical-scavenging and reductase activities. A1M can be internalized by cells, localized to the mitochondria and protect mitochondrial function. Due to its small size, A1M is filtered from the blood into the glomeruli, and taken up by the renal tubular epithelial cells. A1M has previously been described to reduce renal damage in animal models of preeclampsia, radiotherapy and rhabdomyolysis, and is proposed as a pharmacological agent for the treatment of kidney damage. In this paper, we examined the in vitro protective effects of recombinant human A1M (rA1M) in human proximal tubule epithelial cells. Moreover, rA1M was found to protect against heme-induced cell-death both in primary cells (RPTEC) and in a cell-line (HK-2). Expression of stress-related genes was upregulated in both cell cultures in response to heme exposure, as measured by qPCR and confirmed with in situ hybridization in HK-2 cells, whereas co-treatment with rA1M counteracted the upregulation. Mitochondrial respiration, analyzed with the Seahorse extracellular flux analyzer, was compromised following exposure to heme, but preserved by co-treatment with rA1M. Finally, heme addition to RPTE cells induced an upregulation of the endogenous cellular expression of A1M, via activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)-pathway. Overall, data suggest that A1M/rA1M protects against stress-induced damage to tubule epithelial cells that, at least partly, can be attributed to maintaining mitochondrial function.

Download Full-text

Protective Effect of Decursin Extracted fromAngelica gigasin Male Infertility via Nrf2/HO-1 Signaling Pathway

Oxidative Medicine and Cellular Longevity ◽

10.1155/2016/5901098 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9 ◽

Cited By ~ 13

Author(s):

Woong Jin Bae ◽

U. Syn Ha ◽

Jin Bong Choi ◽

Kang Sup Kim ◽

Su Jin Kim ◽

...

Keyword(s):

Oxidative Stress ◽

Semen Quality ◽

Antioxidant Activities ◽

Control Group ◽

Heme Oxygenase 1 ◽

Related Factor ◽

Dependent Manner ◽

Testicular Weight ◽

Unilateral Cryptorchidism

Higher testicular temperature results in altered spermatogenesis due to heat-related oxidative stress. We examined the effects of decursin extracted fromAngelica gigasNakai on antioxidant activityin vitroand in a cryptorchidism-induced infertility rat model. TM3 Leydig cell viability was measured based on oxidative stress according to treatment. Either distilled water or AG 400 mg/kg ofA. gigasextract was administered orally for 4 weeks after unilateral cryptorchidism was induced. After 1, 2, and 4 weeks, six rats from the control group and six rats from treatment group were sacrificed. Testicular weight, semen quality, antioxidant activities, nuclear factor erythroid 2-related factor 2 (Nrf2) protein, and mRNA expression of Nrf2-regulated genes were analyzed. Treatment withA. gigasextract (1) protected TM3 cells against oxidative stress in a dose-dependent manner, (2) improved the mean weight of the cryptorchid testis, (3) maintained sperm counts, motility, and spermatogenic cell density, (4) decreased levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and increased levels of superoxide dismutase (SOD), (5) significantly increased Nrf2 and heme oxygenase-1 (HO-1), and (6) significantly decreased apoptosis. This study suggests that decursin extracted fromA. gigasis a supplemental agent that can reduce oxidative stress by Nrf2-mediated upregulation of HO-1 in rat experimentally induced unilateral cryptorchidism and may improve cryptorchidism-induced infertility.

Download Full-text