Antioxidant Proteins Research Articles

Investigation of the Immunogenic Properties of Ovalbumin Modified by Urban Airborne Particulate Matter

Exposure to air particulate matter (PM) is linked to the blood oxidative stress and systemic inflammation. The aim of this study was to elucidate whether oxidative PM modification of ovalbumin (OVA), the major antioxidant serum protein, may alter its antigenicity and/or immunogenicity. Ovalbumin was exposed via dialysis to the standard urban PM (SRM 1648a) or to PM with removed organic content (encoded as LAP). Both structural changes and biological properties of PM-modified OVA were measured. T lymphocytes and dendritic cells (the major antigen-presenting cells) isolated from C57BL/6 and OT-II (323–339 epitope) OVA-specific T cell receptor (TCR)-transgenic mice were used to test the effect of PM on OVA immunogenicity. The immunogenicity of both SRM 1648a and LAP-modified OVA was significantly higher than that of control OVA, as measured by the epitope-specific T cell proliferation and interferon γ production by the stimulated cells. This effect was associated with mild oxidative changes in the carrier molecule outside the structure of the OVA epitope and with increased resistance to proteolysis of PM-modified OVA. Interestingly, dendritic cells showed enhanced capacity for the uptake of proteins when the cells were cultured with PM-modified OVA. Our results suggest that the enhanced immunogenicity of PM-modified OVA is not associated with altered antigenicity or antigen presentation. However, it may result from slower degradation and longer persistence of modified antigens in dendritic cells. Whether this phenomenon is associated with enhanced risk prevalence of autoimmune diseases observed in the areas with high urban PM pollution needs to be explained.

Inhibition of Mitochondrial Antioxidant Defense and CDK4/6 in Mesothelioma.

Advanced mesothelioma is considered an incurable disease and new treatment strategies are needed. Previous studies have demonstrated that mitochondrial antioxidant defense proteins and the cell cycle may contribute to mesothelioma growth, and that the inhibition of these pathways may be effective against this cancer. We demonstrated that the antioxidant defense inhibitor auranofin and the cyclin-dependent kinase 4/6 inhibitor palbociclib could decrease mesothelioma cell proliferation alone or in combination. In addition, we determined the effects of these compounds on colony growth, cell cycle progression, and the expression of key antioxidant defense and cell cycle proteins. Auranofin and palbociclib were effective in decreasing cell growth and inhibiting the above-described activity across all assays. Further study of this drug combination will elucidate the contribution of these pathways to mesothelioma activity and may reveal a new treatment strategy.

Hyperglycemia and Oxidative Stress: An Integral, Updated and Critical Overview of Their Metabolic Interconnections.

This review focuses on the multiple and reciprocal relationships that exist between oxidative stress, hyperglycemia and diabetes and related metabolic disorders. Human metabolism uses most of the consumed glucose under aerobic conditions. Oxygen is needed in the mitochondria to obtain energy, as well as for the action of microsomal oxidases and cytosolic pro-oxidant enzymes. This relentlessly generates a certain amount of reactive oxygen species (ROS). Although ROS are intracellular signals necessary for some physiological processes, their accumulation leads to oxidative stress, hyperglycemia, and progressive resistance to insulin. A cellular pro-oxidant versus an antioxidant equilibrium would regulate ROS levels, but oxidative stress, hyperglycemia, and pro-inflammatory conditions feed back to each other and the relevance of the interconnections tends to increase those conditions. Hyperglycemia promotes collateral glucose metabolism through protein kinase C, polyols and hexosamine routes. In addition, it also facilitates spontaneous glucose auto-oxidation and the formation of advanced glycation end products (AGEs), which in turn interact with their receptors (RAGE). The mentioned processes undermine cellular structures, finally giving place to a progressively greater degree of oxidative stress with further hyperglycemia, metabolic alterations, and diabetes complications. NFκB is the major transcription factor involved in the expression of most of the pro-oxidant mediators, while Nrf2 is the major transcription factor regulating the antioxidant response. FoxO is also involved in the equilibrium, but its role is controversial. This review summarizes the key factors linking the diverse glucose metabolic routes enhanced in hyperglycemia with ROS formation and vice versa, emphasizing the role of the major transcription factors involved in the desirable balance between pro-oxidant and antioxidant proteins.

The Polymorphisms in GSTO Genes (GSTO1 rs4925, GSTO2 rs156697, and GSTO2 rs2297235) Affect the Risk for Testicular Germ Cell Tumor Development: A Pilot Study.

Members of the omega class of glutathione transferases (GSTs), GSTO1, and GSTO2, catalyze a range of reduction reactions as a part of the antioxidant defense system. Polymorphisms of genes encoding antioxidant proteins and the resultant altered redox profile have already been associated with the increased risk for testicular germ cell cancer (GCT) development. The aim of this pilot study was to assess the individual, combined, haplotype, and cumulative effect of GSTO1rs4925, GSTO2rs156697, and GSTO2rs2297235 polymorphisms with the risk for testicular GCT development, in 88 patients and 96 matched controls, through logistic regression models. We found that carriers of the GSTO1*C/A*C/C genotype exhibited an increased risk for testicular GCT development. Significant association with increased risk of testicular GCT was observed in carriers of GSTO2rs2297235*A/G*G/G genotype, and in carriers of combined GSTO2rs156697*A/G*G/G and GSTO2rs2297235*A/G*G/G genotypes. Haplotype H7 (GSTO1rs4925*C/GSTO2rs2297235*G/GSTO2rs156697*G) exhibited higher risk of testicular GCT, however, without significant association (p > 0.05). Finally, 51% of testicular GCT patients were the carriers of all three risk-associated genotypes, with 2.5-fold increased cumulative risk. In conclusion, the results of this pilot study suggest that GSTO polymorphisms might affect the protective antioxidant activity of GSTO isoenzymes, therefore predisposing susceptible individuals toward higher risk for testicular GCT development.

Elucidation of the Binding Mechanism of Anionic Phospholipids to Antioxidant Protein Peroxiredoxin 2.

Peroxiredoxins (Prxs) belong to a family of ubiquitously expressed peroxidases that detoxify reactive oxygen species. In addition to their enzymatic function, Prxs also function as molecular chaperones. This functional switch is related to their degree of oligomerization. We have previously revealed that Prx2 interacts with anionic phospholipids and that the anionic phospholipid-containing Prx2 oligomer forms a high molecular weight (HMW) complex in a nucleotide-dependent manner. However, the detailed mechanism of the oligomer and HMW complex formation remains unclear. In this study, we investigated the anionic phospholipid binding site in Prx2 using site-directed mutagenesis to understand the mechanism of the oligomer formation. Our findings demonstrated that six binding site residues in Prx2 are important for the binding of anionic phospholipids.

Alterations in skeletal muscle abundance of protein turnover, stress, and antioxidant proteins during the periparturient period in dairy cows fed ethyl-cellulose rumen-protected methionine

Skeletal muscle turnover helps support the physiological needs of dairy cows during the transition into lactation. We evaluated effects of feeding ethyl-cellulose rumen-protected methionine (RPM) during the periparturient period on abundance of proteins associated with transport AA and glucose, protein turnover, metabolism, and antioxidant pathways in skeletal muscle. Sixty multiparous Holstein cows were used in a block design and assigned to a control or RPM diet from -28 to 60 d in milk. The RPM was fed at a rate of 0.09% or 0.10% of dry matter intake (DMI) during the prepartal and postpartal periods to achieve a target Lys:Met ratio in the metabolizable protein of ∼2.8:1. Muscle biopsies from the hind leg of 10 clinically healthy cows per diet collected at -21, 1, and 21 d relative to calving were used for western blotting of 38 target proteins. Statistical analysis was performed using the PROC MIXED statement of SAS version 9.4 (SAS Institute Inc.) with cow as random effect, whereas diet, time, and diet × time were the fixed effects. Diet × time tended to affect prepartum DMI, with RPM cows consuming 15.2 kg/d and controls 14.6 kg/d. However, diet had no effect on postpartum DMI (17.2 and 17.1 ± 0.4 kg/d for control and RPM, respectively). Milk yield during the first 30 d in milk was also not affected by diet (38.1 and 37.5 ± 1.9 kg/d for control and RPM, respectively). Diet or time did not affect the abundance of several AA transporters or the insulin-induced glucose transporter (SLC2A4). Among evaluated proteins, feeding RPM led to lower overall abundance of proteins associated with protein synthesis (phosphorylated EEF2, phosphorylated RPS6KB1), mTOR activation (RRAGA), proteasome degradation (UBA1), cellular stress responses (HSP70, phosphorylated MAPK3, phosphorylated EIF2A, ERK1/2), antioxidant response (GPX3), and de novo synthesis of phospholipids (PEMT). Regardless of diet, there was an increase in the abundance of the active form of the master regulator of protein synthesis phosphorylated MTOR and the growth-factor-induced serine/threonine kinase phosphorylated AKT1 and PIK3C3, whereas the abundance of a negative regulator of translation (phosphorylated EEF2K) decreased over time. Compared with d 1 after calving and regardless of diet, the abundance of proteins associated with endoplasmic reticulum stress (XBP1 spliced), cell growth and survival (phosphorylated MAPK3), inflammation (transcription factor p65), antioxidant responses (KEAP1), and circadian regulation (CLOCK, PER2) of oxidative metabolism was upregulated at d 21 relative to parturition. These responses coupled with the upregulation of transporters for Lys, Arg, and His (SLC7A1) and glutamate/aspartate (SLC1A3) over time were suggestive of dynamic adaptations in cellular functions. Overall, management approaches that could take advantage of this physiological plasticity may help cows make a smoother transition into lactation.

Proteomics and Lysine Acetylation Modification Reveal the Responses of Pakchoi (Brassica rapa L. ssp. chinensis) to Oxybenzone Stress.

The broad-spectrum UV filter oxybenzone is toxic to plants at environmentally relevant concentrations. Lysine acetylation (LysAc) is one of the essential post-translational modifications (PTMs) in plant signaling responses. The goal of this study was to uncover the LysAc regulatory mechanism in response to toxic exposures to oxybenzone as a first step in elucidating xenobiotic acclimatory reactions by using the model Brassica rapa L. ssp. chinensis. A total of 6124 sites on 2497 proteins were acetylated, 63 proteins were differentially abundant, and 162 proteins were differentially acetylated under oxybenzone treatment. Bioinformatics analysis showed that a large number of antioxidant proteins were significantly acetylated under oxybenzone treatment, implying that LysAc alleviated the adverse effects of reactive oxygen species (ROS) by inducing antioxidant systems and stress-related proteins; the significant changes in acetylation modification of enzymes involved in different branches of carbon metabolism in plants under oxybenzone treatment mean that plants can change the direction of carbon flow allocation by regulating the activities of carbon metabolism-related enzymes. Our results profile the protein LysAc under oxybenzone treatment and propose an adaptive mechanism at the post-translational level of vascular plants in response to pollutants, providing a dataset reference for future related research.

BET Protein Inhibitor JQ1 Modulates Mitochondrial Dysfunction and Oxidative Stress Induced by Chronic Kidney Disease.

Among the mechanisms involved in the progression of kidney disease, mitochondrial dysfunction has special relevance. Epigenetic drugs such as inhibitors of extra-terminal domain proteins (iBET) have shown beneficial effects in experimental kidney disease, mainly by inhibiting proliferative and inflammatory responses. The impact of iBET on mitochondrial damage was explored in in vitro studies in renal cells stimulated with TGF-β1 and in vivo in murine unilateral ureteral obstruction (UUO) model of progressive kidney damage. In vitro, JQ1 pretreatment prevented the TGF-β1-induced downregulation of components of the oxidative phosphorylation chain (OXPHOS), such as cytochrome C and CV-ATP5a in human proximal tubular cells. In addition, JQ1 also prevented the altered mitochondrial dynamics by avoiding the increase in the DRP-1 fission factor. In UUO model, renal gene expression levels of cytochrome C and CV-ATP5a as well as protein levels of cytochrome C were reduced These changes were prevented by JQ1 administration. In addition, JQ1 decreased protein levels of the DRP1 fission protein and increased the OPA-1 fusion protein, restoring mitochondrial dynamics. Mitochondria also participate in the maintenance of redox balance. JQ1 restored the gene expression of antioxidant proteins, such as Catalase and Heme oxygenase 1 in TGF-β1-stimulated human proximal tubular cells and in murine obstructed kidneys. Indeed, in tubular cells, JQ1 decreased ROS production induced by stimulation with TGF-β1, as evaluated by MitoSOXTM. iBETs, such as JQ1, improve mitochondrial dynamics, functionality, and oxidative stress in kidney disease.

Proteomic Analysis of Mesenchymal Stem Cells and Monocyte Co-Cultures Exposed to a Bioactive Silica-Based Sol-Gel Coating.

New methodologies capable of extensively analyzing the cell-material interactions are necessary to improve current in vitro characterization methods, and proteomics is a viable alternative. Also, many studies are focused on monocultures, even though co-cultures model better the natural tissue. For instance, human mesenchymal stem cells (MSCs) modulate immune responses and promote bone repair through interaction with other cell types. Here, label-free liquid chromatography tandem mass spectroscopy proteomic methods were applied for the first time to characterize HUCPV (MSC) and CD14+ monocytes co-cultures exposed to a bioactive sol-gel coating (MT). PANTHER, DAVID, and STRING were employed for data integration. Fluorescence microscopy, enzyme-linked immunosorbent assay, and ALP activity were measured for further characterization. Regarding the HUCPV response, MT mainly affected cell adhesion by decreasing integrins, RHOC, and CAD13 expression. In contrast, MT augmented CD14+ cell areas and integrins, Rho family GTPases, actins, myosins, and 14-3-3 expression. Also, anti-inflammatory (APOE, LEG9, LEG3, and LEG1) and antioxidant (peroxiredoxins, GSTO1, GPX1, GSHR, CATA, and SODM) proteins were overexpressed. On co-cultures, collagens (CO5A1, CO3A1, CO6A1, CO6A2, CO1A2, CO1A1, and CO6A3), cell adhesion, and pro-inflammatory proteins were downregulated. Thus, cell adhesion appears to be mainly regulated by the material, while inflammation is impacted by both cellular cross-talk and the material. Altogether, we conclude that applied proteomic approaches show its potential in biomaterial characterization, even in complex systems.

Glutaredoxin 1 from evolutionary ancient <i>Hydra</i>: characteristics of the enzyme and its possible functions in cell

Glutaredoxin (Grx) is an antioxidant redox protein that uses glutathione (GSH) as an electron donor. Grx plays a crucial role in various cellular processes, such as antioxidant defense, control of cellular redox state, redox control of transcription, reversible S-glutathionylation of specific proteins, apoptosis, cell differentiation, etc. In the current study, we have isolated and characterized dithiol glutaredoxin from Hydra vulgaris Ind-Pune (HvGrx1). Sequence analysis showed that HvGrx1 belongs to the Grx family with the classical Grx motif (CPYC). Phylogenetic analysis and homology modeling revealed that HvGrx1 is closely related to Grx2 from zebrafish. HvGrx1 gene was cloned and expressed in Escherichia coli cells; the purified protein had a molecular weight of 11.82 kDa. HvGrx1 efficiently reduced β-hydroxyethyl disulfide (HED) with the temperature optimum of 25°C and pH optimum 8.0. HvGrx1 was ubiquitously expressed in all body parts of Hydra. Expression of HvGrx1 mRNA and enzymatic activity of HvGrx1 were significantly upregulated post H2O2 treatment. When expressed in human cells, HvGrx1 protected the cells from oxidative stress and enhanced cell proliferation and migration. Although Hydra is a simple invertebrate, HvGrx1 is evolutionary closer to its homologs from higher vertebrates (similar to many other Hydra proteins).

USP14 regulates heme metabolism and ovarian cancer invasion through BACH1 deubiquitination and stabilization

The deubiquitinating enzyme USP14 has been established as a crucial regulator in various diseases, including tumors, neurodegenerative diseases, and metabolic diseases, through its ability to stabilize its substrate proteins. Our group has utilized proteomic techniques to identify new potential substrate proteins for USP14, however, the underlying signaling pathways regulated by USP14 remain largely unknown. Here, we demonstrate the key role of USP14 in both heme metabolism and tumor invasion by stabilizing the protein BACH1. The cellular oxidative stress response factor NRF2 regulates antioxidant protein expression through binding to the antioxidant response element (ARE). BACH1 can compete with NRF2 for ARE binding, leading to the inhibition of the expression of antioxidant genes, including HMOX-1. Activated NRF2 also inhibits the degradation of BACH1, promoting cancer cell invasion and metastasis. Our findings showed a positive correlation between USP14 expression and NRF2 expression in various cancer tissues from the TCGA database and normal tissues from the GTEx database. Furthermore, activated NRF2 was found to increase USP14 expression in ovarian cancer (OV) cells. The overexpression of USP14 was observed to inhibit HMOX1 expression, while USP14 knockdown had the opposite effect, suggesting a role for USP14 in regulating heme metabolism. The depletion of BACH1 or inhibition of heme oxygenase 1 (coded by HMOX-1) was also found to significantly impair USP14-dependent OV cell invasion. In conclusion, our results highlight the importance of the NRF2-USP14-BACH1 axis in regulating OV cell invasion and heme metabolism, providing evidence for its potential as a therapeutic target in related diseases.

Improving microbial and lipid oxidative stability of cheddar cheese using cricket protein hydrolysates pre-treated with microwave and ultrasonication

The study was carried out to investigate cricket protein hydrolysates’ (CPH) potential to enhance the storage stability of cheddar cheese. The cricket protein (CP) samples pre-processed with microwave (T1), ultrasonication (T2) or without pre-treatment (T0) were used for developing the CPH using alcalase enzyme (3%). Freeze-dried CPH were incorporated in the cheese samples (CPH-T1, CPH-T2 and CPH-T0) at the maximum level of 1.5% and were analysed for quality during 3 months of storage (4 ± 1 °C) compared to the control samples without CPH. The pre-treatments significantly improved the antimicrobial and antioxidant potential of the CPH. The CPH exhibited a significant positive effect on antioxidant potential, lipid stability, protein oxidation, microbial growth, and sensory quality of the cheddar cheese during storage. Digestion simulation showed a significant positive impact on the antioxidant activity of the cheddar cheese. Our results indicate the potential of CPH to enhance the quality of fat-rich foods during storage.

Functions of Astrocytes under Normal Conditions and after a Brain Disease.

In the central nervous system (CNS) there are a greater number of glial cells than neurons (between five and ten times more). Furthermore, they have a greater number of functions (more than eight functions). Glia comprises different types of cells, those of neural origin (astrocytes, radial glia, and oligodendroglia) and differentiated blood monocytes (microglia). During ontogeny, neurons develop earlier (at fetal day 15 in the rat) and astrocytes develop later (at fetal day 21 in the rat), which could indicate their important and crucial role in the CNS. Analysis of the phylogeny reveals that reptiles have a lower number of astrocytes compared to neurons and in humans this is reversed, as there have a greater number of astrocytes compared to neurons. These data perhaps imply that astrocytes are important and special cells, involved in many vital functions, including memory, and learning processes. In addition, astrocytes are involved in different mechanisms that protect the CNS through the production of antioxidant and anti-inflammatory proteins and they clean the extracellular environment and help neurons to communicate correctly with each other. The production of inflammatory mediators is important to prevent changes in brain homeostasis. On the contrary, excessive, or continued production appears as a characteristic element in many diseases, such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and in neurodevelopmental diseases, such as bipolar disorder, schizophrenia, and autism. Furthermore, different drugs and techniques have been developed to reverse oxidative stress and/or excess of inflammation that occurs in many CNS diseases, but much remains to be investigated. This review attempts to highlight the functional relevance of astrocytes in normal and neuropathological conditions by showing the molecular and cellular mechanisms of their role in the CNS.

Age and oxidative stress regulate Nrf2 homeostasis in human articular chondrocytes

The purpose of this study was to investigate the effect of age and oxidative stress on regulation of nuclear factor erythroid-2-related factor 2 (Nrf2) in young, old, and osteoarthritic (OA) human articular chondrocytes. Levels of Nrf2 in primary human chondrocytes isolated from young, old, and OA donors were measured by immunoblotting, qPCR, and immunohistochemistry. Effects on levels of Nrf2, antioxidant proteins regulated by Nrf2, as well as p65, and the anabolic response to insulin-like growth factor-1 (IGF-1) were evaluated after induction of oxidative stress with menadione, Nrf2 knockdown with siRNA, and/or Nrf2 activation with RTA-408. Nrf2 protein levels were significantly lower in older adult chondrocytes (∼0.59 fold; p=0.034) and OA chondrocytes (∼0.50 fold; p=0.016) compared to younger cells. Menadione significantly increased Nrf2 protein levels in young chondrocytes by just under four-fold without changes in old chondrocytes. Nrf2 knockdown and activation differentially regulated levels of anti-oxidant proteins including sulfiredoxin and NAD(P)H quinone dehydrogenase 1. Nrf2 activation with RTA-408 also decreased basal p65 phosphorylation, increased aggrecan and type II collagen gene expression, and increased production of proteoglycans in OA chondrocytes treated with IGF-1. Targeted therapeutic strategies aimed at maintaining Nrf2 activity could be useful in maintaining chondrocyte homeostasis through maintenance of intracellular antioxidant function and redox balance.

Microalgae Produce Antioxidant Molecules with Potential Preventive Effects on Mitochondrial Functions and Skeletal Muscular Oxidative Stress.

In recent years, microalgae have become a source of molecules for a healthy life. Their composition of carbohydrates, peptides, lipids, vitamins and carotenoids makes them a promising new source of antioxidant molecules. Skeletal muscle is a tissue that requires constant remodeling via protein turnover, and its regular functioning consumes energy in the form of adenosine triphosphate (ATP), which is produced by mitochondria. Under conditions of traumatic exercise or muscular diseases, a high production of reactive oxygen species (ROS) at the origin of oxidative stress (OS) will lead to inflammation and muscle atrophy, with life-long consequences. In this review, we describe the potential antioxidant effects of microalgae and their biomolecules on mitochondrial functions and skeletal muscular oxidative stress during exercises or in musculoskeletal diseases, as in sarcopenia, chronic obstructive pulmonary disease (COPD) and Duchenne muscular dystrophy (DMD), through the increase in and regulation of antioxidant pathways and protein synthesis.

Effects of Leptin and Body Weight on Inflammation and Knee Osteoarthritis Phenotypes in Female Rats.

Leptin is a proinflammatory adipokine that contributes to obesity-associated osteoarthritis (OA), especially in women. However, the extent to which leptin causes knee OA separate from the effect of increased body weight is not clear. We hypothesized that leptin is necessary to induce knee OA in obese female rats but not sufficient to induce knee OA in lean rats lacking systemic metabolic inflammation. The effect of obesity without leptin signaling was modeled by comparing female lean Zucker rats to pair fed obese Zucker rats, which possess mutant fa alleles of the leptin receptor gene. The effect of leptin without obesity was modeled in female F344BN F1 hybrid rats by systemically administering recombinant rat leptin versus saline for 23 weeks via osmotic pumps. Primary OA outcomes included cartilage histopathology and subchondral bone micro-computed tomography. Secondary outcomes included targeted cartilage proteomics, serum inflammation, and synovial fluid inflammation following an acute intra-articular challenge with interleukin-1β (IL-1β). Compared to lean Zucker rats, obese Zucker rats developed more severe tibial osteophytes and focal cartilage lesions in the medial tibial plateau, with modest changes in proximal tibial epiphysis trabecular bone structure. In contrast, exogenous leptin treatment, which increased plasma leptin sixfold without altering body weight, caused mild generalized cartilage fibrillation and reduced Safranin O staining compared to vehicle-treated animals. Leptin also significantly increased subchondral and trabecular bone volume and bone mineral density in the proximal tibia. Cartilage metabolic and antioxidant enzyme protein levels were substantially elevated with leptin deficiency and minimally suppressed with leptin treatment. In contrast, leptin treatment induced greater changes in systemic and local inflammatory mediators compared to leptin receptor deficiency, including reduced serum IL-6 and increased synovial fluid IL-1β. In conclusion, rat models that separately elevate leptin or body weight develop distinct OA-associated phenotypes, revealing how obesity increases OA pathology through both leptin-dependent and independent pathways. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

The protective effects of sophocarpine on sepsis-induced cardiomyopathy

This investigation elucidates the impact of sophocarpine treatment on lipopolysaccharide (LPS) stimulated sepsis-induced cardiomyopathy (SIC) via in vivo and in vitro experiments. Echocardiography, ELISA, TUNEL, Western blotting experiments, and Hematoxylin/Eosin, Dihydroethidium, and Immunohistochemistry staining assays, were carried out to identify associated indicators. The echocardiography revealed that sophocarpine treatment alleviated LPS-induced cardiac dysfunction as indicated by fractional shortening shortened and improved ejection fraction. Heart injury biomarkers, such as creatine kinase, lactate dehydrogenase, and creatine kinase-MB, were assessed, and indicated that sophocarpine treatment could alleviate LPS-induced upregulation of these indices. Furthermore, different experimental protocols revealed that sophocarpine treatment inhibits LPS-induced pathological alterations and decreases LPS-stimulated inflammatory cytokines, IL-1β, monocyte chemoattractant protein-1, IL-6, NOD-like receptor protein-3, and TNF-α, increase. Apoptotic proteins such as cytochrome-c, Bax, and cleaved-caspase-3 were increased, and Bcl-2 was alleviated after LPS stimulation; however, these effects were inhibited by sophocarpine treatment. Decreased antioxidant proteins [superoxide dismutase-1 (SOD-1) and SOD-2] induced by LPS stimulation were upregulated by sophocarpine treatment. LPS upregulated autophagic proteins such as Beclin-1 and the ratio of microtubule-associated protein 1A/1B-light chain 3 (LC3)-II/LC3-I and downregulated sequestosome 1 (SQSTM1, or P62), sophocarpine therapy reversed these effects. Moreover, it was indicated that sophocarpine treatment inhibited the Toll-like receptor-4 (TLR-4)/nuclear transcription factor-kappa B (NF-κB) signaling pathway and activated nuclear factor erythroid 2-related factor-2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. In conclusion, sophocarpine treatment could alleviate LPS-trigger SIC by repressing oxidative stress, autophagy, inflammation, and apoptosis via TLR-4/NF-κB inhibition and Nrf2/HO-1 signaling pathway activation, implicating the potential of sophocarpine as a new therapeutic approach against SIC.

The Role of Skeletal Muscle Nrf2 on Cardiac Function in Mice

Introduction: Excessive oxidant stress has been shown to damage cardiac tissue and result in impaired cardiac function. Animals with chronic heart failure (CHF) exhibit lower levels of antioxidant enzymes in many tissues including the heart, brain, and skeletal muscle (SkM). Nrf2 is a ubiquitous master transcription factor that regulates antioxidant proteins during enhanced oxidative stress. Earlier studies from this laboratory showed that exercise training was cardioprotective following ischemia reperfusion injury in mice. This protective effect was abrogated in mice in which the Nrf2 gene was deleted selectively in skeletal muscle. Given that skeletal muscle is approximately 40% of body weight and in light of recent findings on skeletal muscle derived extracellular vesicles, we sought to determine if up and downregulation of Nrf2 in skeletal muscle altered cardiac function. We hypothesized that skeletal muscle knockout of Nrf2 would impair cardiac function and the response to the beta 1 agonist dobutamine. Materials and Methods: Experiments were carried out in 37 males iMS-Keap1flox/flox and iMS-Nrf-2flox/flox (i.e. SkM specific) mice. Gene deletion was conditional upon the administration of the estrogen receptor agonist tamoxifen at 3 months of age; floxed mice given vehicle instead of tamoxifen were considered WT. The mice were assigned to 4 groups: Keap1 knockout (KO) (10), Keap1 WT (8), Nrf-2 KO (11), and Nrf-2 WT (8). Results: Keap1 deletion resulted in an increase in skeletal muscle hemoxygenase 1 (HO1) (p = 0.0286) while Nrf2 deletion resulted in a reduction in HO1 (p = 0.0286). However, there were no changes in the level of HO1 or other antioxidant proteins in the heart. Cardiac function was assessed with high frequency echocardiography (Vevo 3100). Systolic and diastolic function were analyzed. Up and downregulation of skeletal muscle Nrf2 did not evoke any change in either systolic or diastolic function. Conclusions: Previous studies have shown that Nrf2 upregulation salvaged cardiac function in mice subjected to either myocardial infarction or thoracic aortic constriction. Therefore, it may be that our lack of an effect of SkM specific Nrf2 manipulation is due to this study being carried out in normal animals and not in a disease setting such as CHF. In future work, this effect will be examined in mice with cardiac dysfunction. Supported by P0162222 and SURF from the APS This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Renal mitochondrial metabolism is differentially regulated in male and female kidneys in Ang II -- induced hypertension

Introduction. In 2020, more than 670,000 deaths in the United States had hypertension as a primary or contributing cause. Females generally exhibit less susceptibility to hypertensive renal damage compared to males. It is established that renal mitochondrial dysfunction and associated oxidative stress contribute to hypertension development. Our previous studies have shown that healthy renal mitochondria in the absence of hypertension exhibit sex differences in antioxidant protein abundance, ROS production, and oxygen consumption rates. We hypothesized here that in hypertensive state mitochondrial metabolism in male and female kidneys differentially regulates tissue damage and ultimately hypertension in females. Methods. To address our hypothesis, we used 11-week-old male and female Sprague Dawley rats infused with Angiotensin II (400 ng/kg/min to induce hypertension) or vehicle for 3 weeks via a s.c. osmotic pump. Mitochondria were isolated from the renal cortex and medulla of these rats; mitochondrial membrane potential and H 2 O 2 production were measured by spectrofluorimetry using TMRM and Amplex Red dyes. Two-way ANOVA was utilized for statistical analysis in OriginPro. Metabolic profiles of renal cortices and medullae were generated using UHPLC-HRMS, and metabolites were identified by retention time exact mass using MAVEN and MetaboAnalyst software. Results. Spectrofluorimetry showed decreased membrane potential in both male and female renal medulla in animals infused with Ang II compared to vehicle (p<0.001), while in cortex this difference was only recorded in females (p=0.03). Ang II-infusion reduced H 2 O 2 production in the renal cortex and medulla of female rats (p<0.001) compared to sham groups, while this was not observed in males. In both Ang II and vehicle-infused groups, females maintained higher H 2 O 2 production compared to males. UHPLC-HRMS identified 147 mitochondria-related metabolites in each group. Ang II infusion increased TCA cycle and purine metabolites as well as amino acids in the cortex of both sexes and in male medulla, whereas these changes were not revealed in the female medulla. Interestingly, females exhibited a decrease in amino acid metabolism in the renal medulla. In contrast to the male cortex, the female cortex is responding to oxidative stress induced by hypertension by altering arginine biosynthesis and metabolism. Arginine is a biosynthetic precursor to putrescine, which is involved in polyamine biosynthesis. Conclusions. Male and female kidneys employ divergent metabolic mitochondria-related pathways in hypertensive state. The male cortex may rely more on protein degradation to produce uric acid, an antioxidant, while the female cortex utilizes protein degradation and polyamine biosynthesis in oxidative stress management. R01HL148114 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Toxicity attenuation processing technology and mechanism of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction

This study explored toxicity attenuation processing technology of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction for the first time, and further explored its detoxification mechanism. Nine processed products of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction were prepared by orthogonal experiment with three factors and three levels. Based on the decrease in the content of the main hepatotoxic component diosbulbin B before and after processing of Rhizoma Dioscoreae Bulbiferae by high-performance liquid chromatography, the toxicity attenuation technology was preliminarily screened out. On this basis, the raw and representative processed products of Rhizoma Dioscoreae Bulbiferae were given to mice by gavage with 2 g·kg~(-1)(equival to clinical equivalent dose) for 21 d. The serum and liver tissues were collected after the last administration for 24 h. The serum biochemical indexes reflecting liver function and liver histopathology were combined to further screen out and verify the proces-sing technology. Then, the lipid peroxidation and antioxidant indexes of liver tissue were detected by kit method, and the expressions of NADPH quinone oxidoreductase 1(NQO1) and glutamate-cysteine ligase(GCLM) in mice liver were detected by Western blot to further explore detoxification mechanism. The results showed that the processed products of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction reduced the content of diosbulbin B and improved the liver injury induced by Rhizoma Dioscoreae Bul-biferae to varying degrees, and the processing technology of A_2B_2C_3 reduced the excessive levels of alanine transaminase(ALT) and aspartate transaminase(AST) induced by raw Rhizoma Dioscoreae Bulbiferae by 50.2% and 42.4%, respectively(P<0.01, P<0.01). The processed products of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction reversed the decrease protein expression levels of NQO1 and GCLM in the liver of mice induced by raw Rhizoma Dioscoreae Bulbiferae to varying degrees(P<0.05 or P<0.01), and it also reversed the increasing level of malondialdehyde(MDA) and the decreasing levels of glutathione(GSH), glutathione peroxidase(GPX), and glutathione S-transferase(GST) in the liver of mice(P<0.05 or P<0.01). In summary, this study shows that the optimal toxicity attenuation processing technology of Rhizoma Dioscoreae Bulbiferae stir-fried with Paeoniae Radix Alba decoction is A_2B_2C_3, that is, 10% of Paeoniae Radix Alba decoction is used for moistening Rhizoma Dioscoreae Bulbiferae and processed at 130 ℃ for 11 min. The detoxification mechanism involves enhancing the expression levels of NQO1 and GCLM antio-xidant proteins and related antioxidant enzymes in the liver.