Oxidative Stress Conditions Research Articles

A comprehensive study on the identification and characterization of major degradation products of synthetic liraglutide using liquid chromatography-high resolution mass spectrometry.

Liraglutide (LGT) is a synthetic glucagon-like peptide-1 analogue mainly used for the treatment of type-2 diabetes or obesity. Comprehensive stability testing is essential in the development and routine quality control of synthetic therapeutic peptide pharmaceuticals. The GLP-1 peptide drugs are usually formulated in aqueous-base solution, which can generate stability issues during manufacturing, storage or shipment. The current study endeavors to observe the chemical stability behavior of LGT by exposing the drug substance to oxidative and hydrolytic stress conditions. A simple liquid chromatography (LC) method was developed where sufficient resolution between LGT and the generated degradation products was achieved. In total, 19 degradation products (DPs) were separated under acidic, basic and oxidative stress conditions. Using LC-HRMS, MS/MS studies, the generated degradation products were identified and characterized. The mechanistic fragmentation pathway for all generated DPs were established and the plausible chemical structure for the identified DPs was predicted based on MS/MS data. The results strongly suggest that LGT is highly susceptible to degrade under oxidative and hydrolytic conditions. Furthermore, this study provides insights into the hydrolytic and oxidative stability of LGT, which can be implied during generic and novel formulation drug development and discovery in synthesizing relatively stable GLP-1 analogues.

Efficacy of Saccharomyces yeast postbiotics on cell turnover, immune responses, and oxidative stress in the jejunal mucosa of young pigs

This study aimed to determine the effects of Saccharomyces yeast postbiotics on cell turnover, immune responses, and oxidative stress in the jejunal mucosa of pigs. Thirty-two newly weaned pigs at 6.05 ± 0.24 kg were assigned to two dietary treatments based on a randomized complete block design. The treatments were control group receiving a basal diet and a group supplemented with Saccharomyces yeast postbiotics (175 g/ton diet) in the basal diet. After 35 d of the study, pigs were euthanized and jejunal mucosa were collected to assess immune status, oxidative stress, barrier markers, cell proliferation, and apoptosis. Saccharomyces yeast postbiotics reduced (P < 0.05) the fecal score from d 3 to d 7 and tended to increase the gene expression of interferon-γ (IFN-γ) (P = 0.071) and mammalian/mechanistic target of rapamycin (mTOR) (P = 0.080), decrease the gene expression of B-cell lymphoma 2-associated X protein 1 (BAX1) (P < 0.05), tended to decrease the gene expression of serum and glucocorticoid-induced protein kinase 1 (SGK1) (P = 0.066), increased (P < 0.05) cell proliferation in the crypts, and tended to increase the villus height (P = 0.078) and crypt depth (P = 0.052) in the jejunum. In conclusion, the supplementation of Saccharomyces yeast postbiotics in nursery diets reduced diarrhea within the first week after weaning and provided protection to the villi in the jejunum by enhancing the immune responses of nursery pigs, promoting crypt cell proliferation, and reducing the expression of genes associated with apoptosis without affecting inflammatory and oxidative stress status in the jejunum of the nursery pigs.

The KEAP1/PGAM5/AIFM1-Mediated oxeiptosis pathway in Alzheimer’s disease

BackgroundAlzheimer’s Disease (AD) is a neurodegenerative disease with mitochondrial dysfunction and oxidative stress. Oxeiptosis is a cell death pathway sensitive to reactive oxygen species (ROS). This study investigates the role of oxeiptosis pathway and mitochondrial damage in AD. MethodsAn AD model was developed in C57BL/6 mice by injecting Aβ1-42 oligomers into the brain. Cognitive function was tested using the Morris water maze. Exposure of HT22 mouse hippocampal neurons to H2O2 induces oxidative stress. Protein levels of KEAP1, PGAM5 and AIFM1 were analyzed by western blot, and mitochondrial damage was observed with electron microscopy. Cell survival rates were using the CCK8 assay and flow cytometry after knocking down KEAP1, PGAM5 and AIFM1. ResultsThe protein concentrations of KEAP1, PGAM5 and AIFM1 were found to be elevated in the hippocampal tissues of AD mice compared to control group, accompanied by mitochondrial damage in the hippocampal neurons of the AD group. Similarly, in the HT22 oxidative stress model, there was an increase in the protein levels of KEAP1, PGAM5 and AIFM1, along with observed mitochondrial damage. Following individual and combined knockdown of KEAP1, PGAM5 and AIFM1, cell survival rates under oxidative stress conditions were higher compared to H2O2 group, with no significant difference in cell survival rates among the knockdown groups. ConclusionThis research underscores the critical role of the KEAP1/PGAM5/AIFM1-mediated oxeiptosis pathway in neuronal cell death, offering insights into potential therapeutic targets for mitigating neurodegeneration in AD.

Lower distress intolerance is associated with higher glutathione levels in adolescent cannabis users

Cannabis (CB) use and psychological stressors increase oxidative stress in the brain. Glutathione (GSH), the most abundant antioxidant in the brain, protects against oxidative stress. Furthermore, distress intolerance, the inability to tolerate psychological or physiological stress is a risk factor for CB use. The relationship between CB use, brain GSH levels and distress intolerance remains unknown. Therefore, we examined GSH levels in the anterior cingulate cortex (ACC), as a measure of oxidative stress, and its relationship with distress intolerance in adolescent CB users and healthy controls (HC).Sixteen HC and 17 CB-using adolescents were included in the analysis. GSH levels were measured in the ACC using a metabolite-edited proton magnetic resonance spectroscopy sequence on a 3T scanner. Distress intolerance was assessed using the Distress Intolerance Index (DII) and CB use was evaluated using a structured clinical interview.In the CB group, lower CSF-corrected GSH levels in the ACC were correlated with higher DII scores. However, no significant between group differences were observed for ACC CSF-corrected GSH levels or on DII scores. No significant correlations were observed in the HC group between GSH levels and DII.Our findings suggests that the association between lower GSH levels and greater distress intolerance in CB users might reflect alterations in the balance between protective and oxidative stress conditions linked to the ability to tolerate distress. Further examination into this relationship can provide important insights into neurobiological correlates and risk factors associated with CB use to help inform preventive and treatment targets in the future.

TRIM44 enhances autophagy via SQSTM1 oligomerization in response to oxidative stress

The deubiquitinase tripartite motif containing 44 (TRIM44) plays a critical role in linking the proteotoxic stress response with autophagic degradation, which is significant in the context of cancer and neurological diseases. Although TRIM44 is recognized as a prognostic marker in various cancers, the complex molecular mechanisms through which it facilitates autophagic degradation, particularly under oxidative stress conditions, have not been fully explored. In this study, we demonstrate that TRIM44 significantly enhances autophagy in response to oxidative stress, reducing cytotoxicity in cancer cells treated with arsenic trioxide. Our research emphasizes the critical role of the posttranslational modification of sequestosome-1 (SQSTM1) and its importance in improving sequestration during autophagic degradation under oxidative stress. We found that TRIM44 notably promotes SQSTM1 oligomerization in both PB1 domain-dependent and oxidation-dependent manners. Furthermore, TRIM44 amplifies the interaction between protein kinase A and oligomerized SQSTM1, leading to enhanced phosphorylation of SQSTM1 at S349. This phosphorylation event activates NFE2L2, a key transcription factor in the oxidative stress response, highlighting the importance of TRIM44 in modulating SQSTM1-mediated autophagy. Our findings support that TRIM44 plays pivotal roles in regulating autophagic sensitivity to oxidative stress, with implications for cancer, aging, aging-associated diseases, and neurodegenerative disorders.

A protein O-GlcNAc glycosyltransferase regulates the antioxidative response in Yersinia pestis

Post-translational addition of O-linked N-acetylglucosamine (O-GlcNAc) to proteins is commonly associated with a variety of stress responses and cellular processes in eukaryotes, but its potential roles in bacteria are unclear. Here, we show that protein HmwC acts as an O-GlcNAc transferase (OGT) responsible for O-GlcNAcylation of multiple proteins in Yersinia pestis, a flea-borne pathogen responsible for plague. We identify 64 O-GlcNAcylated proteins (comprising 65 sites) with differential abundance under conditions mimicking the mammalian host (Mh) and flea vector (Fv) environments. Deletion of hmwC, encoding a putative OGT, structurally distinct from any existing member of the GT41 family, results in reduced O-GlcNAcylation, reduced growth, and alterations in virulence properties and survival under stress. Purified HmwC can modify target proteins in vitro using UDP-GlcNAc as sugar donor. One of the target proteins, OsdY, promotes Y. pestis survival under oxidative stress conditions. Thus, our results support that regulation of antioxidative responses through O-GlcNAcylation may be a conserved process shared by prokaryotes and eukaryotes.

Antioxidant Activity of the Medicinal Plant Urtica dioica L.: Extraction Optimization Using Response Surface Methodology and Protective Role in Red Blood Cells

Free radicals are highly reactive compounds that lead to the onset of a variety of serious health conditions, known as “oxidative stress”. Antioxidants, on the other hand, act as defense mechanisms to fight the accumulation of free radicals and maintain cell homeostasis. Urtica dioica L. is a medicinal plant with unique antioxidant properties, mainly attributable to the presence of polar phenolic compounds. This study aimed to optimize the combination of determinant factors toward the maximum extraction of antioxidants from U. dioica L. Furthermore, it investigated the protective role of the extract on red blood cells that were exposed to oxidative stress. The extraction optimization was performed using Response Surface Methodology and the in vitro antioxidant activity of the extract was determined with Folin–Ciocalteu, FRAP, and DPPH assays. Based on the results, the highest value of antioxidant activity and polar phenolic compounds was recorded using 34% (v/v) ethanol as a solvent in an ultrasonic process carried out at 42 °C for 87 min. In addition, UV–Vis spectrum of the extract revealed the presence of chlorophylls, carotenoids, and flavonoid glycosides. This study also provided insight into the in vitro protective effect of the plant extract on red blood cells morphology under oxidative stress conditions. The findings highlighted the good predictability of the extraction model and the potential role of the extract as an antioxidant product.

Knocking down EGR1 inhibits nucleus pulposus cell senescence and mitochondrial damage through activation of PINK1-Parkin dependent mitophagy, thereby delaying intervertebral disc degeneration

Mitophagy plays a crucial role in maintaining the homeostasis of intervertebral disc (IVD). Early Growth Response 1 (EGR1), a conservative transcription factor, is commonly upregulated under oxidative stress conditions and participates in regulating cellular senescence, apoptosis, and inflammatory responses. However, the specific role of EGR1 in nucleus pulposus (NP) cell senescence and mitophagy remains unclear. In this study, through bioinformatics analysis and validation using human tissue specimens, we found that EGR1 is significantly upregulated in IVD degeneration (IDD). Further experimental results demonstrate that knockdown of EGR1 inhibits TBHP-induced NP cell senescence and mitochondrial dysfunction while promoting the activation of mitophagy. The protective effect of EGR1 knockdown on NP cell senescence and mitochondrion disappears upon inhibition of mitophagy with mdivi1. Mechanistic studies reveal that EGR1 suppresses NP cell senescence and mitochondrial dysfunction by modulating the PINK1-Parkin dependent mitophagy pathway. Additionally, EGR1 knockdown delays acupuncture-induced IDD in rats. In conclusion, our study demonstrates that under TBHP-induced oxidative stress, EGR1 knockdown mitigates NP cell senescence and mitochondrial dysfunction through the PINK1-Parkin dependent mitophagy pathway, thereby alleviating IDD.

The Antioxidant and Anti-Inflammatory Properties of Bee Pollen from Acorn (Quercus acutissima Carr.) and Darae (Actinidia arguta).

Aging is a complex biological process characterized by a progressive decline in physical function and an increased risk of age-related chronic diseases. Additionally, oxidative stress is known to cause severe tissue damage and inflammation. Pollens from acorn and darae are extensively produced in Korea. However, the underlying molecular mechanisms of these components under the conditions of inflammation and oxidative stress remain largely unknown. This study aimed to investigate the effect of bee pollen components on lipopolysaccharide (LPS)-induced RAW 264.7 mouse macrophages. This study demonstrates that acorn and darae significantly inhibit the LPS-induced production of inflammatory mediators, such as nitric oxide (NO) and prostaglandin E2 (PGE2), in RAW 264.7 cells. Specifically, bee pollen from acorn reduces NO production by 69.23 ± 0.04% and PGE2 production by 44.16 ± 0.08%, while bee pollen from darae decreases NO production by 78.21 ± 0.06% and PGE2 production by 66.23 ± 0.1%. Furthermore, bee pollen from acorn and darae reduced active oxygen species (ROS) production by 47.01 ± 0.5% and 60 ± 0.9%, respectively. It increased the nuclear potential of nuclear factor erythroid 2-related factor 2 (Nrf2) in LPS-stimulated RAW 264.7 cells. Moreover, treatment with acorn and darae abolished the nuclear potential of nuclear factor κB (NF-κB) and reduced the expression of extracellular signal-associated kinase (ERK) and c-Jun N-terminal kinase (JNK) phosphorylation in LPS-stimulated RAW 264.7 cells. Specifically, acorn decreased NF-κB nuclear potential by 90.01 ± 0.3%, ERK phosphorylation by 76.19 ± 1.1%, and JNK phosphorylation by 57.14 ± 1.2%. Similarly, darae reduced NF-κB nuclear potential by 92.21 ± 0.5%, ERK phosphorylation by 61.11 ± 0.8%, and JNK phosphorylation by 59.72 ± 1.12%. These results suggest that acorn and darae could be potential antioxidants and anti-inflammatory agents.

BAG3 Mediated Down-regulation in Expression of p66shc has Ramifications on Cellular Proliferation, Apoptosis and Metastasis.

Redundancy of cancer cells towards ROS-mediated apoptosis despite expressing proline-rich p66shc abundantly needs to be investigated properly. P66shc, an adapter protein, is indispensable both for initiating ROS-mediated apoptosis and subsequent ROS generation through Rac-1 activation. P66shc gets phosphorylated at Ser-36 that triggers its translocation to the mitochondria and subsequent release of Cytochrome c in response to oxidative stress. It also aids in Rac-1 dependent NADPH oxidase activation, leading to the generation of cytosolic ROS that can perform diverse functions depending on its concentration. This study has identified the multi-faceted anti-apoptotic protein BAG3 as an interacting partner of p66shc. BAG3 utilizes its WW domain to bind to the proline-rich motifs of p66shc. BAG3, through its WW domain, antagonizes p66shc mediated apoptosis, by inhibiting both the expression and phosphorylation of p66shc under normal and oxidative stress conditions. This results in significant protection against ROS-mediated apoptosis. BAG3-mediated reduction in p66shc expression increases cell proliferation and metastasis. The increase in cell proliferation is attributed to the impact of BAG3 on Rac-1 activation and ROS production under normal conditions. This study has unraveled an interactor of p66shc that enhances pro-survival role while simultaneously suppressing its apoptotic role.

β-Hydroxybutyrate enhances chondrocyte mitophagy and reduces cartilage degeneration in osteoarthritis via the HCAR2/AMPK/PINK1/Parkin pathway.

Osteoarthritis (OA) is widely recognized as the prevailing joint disease associated with aging. The ketogenic diet (KD) has been postulated to impede the advancement of various inflammatory ailments. β-Hydroxybutyrate (βOHB), a prominent constituent of ketone bodies, has recently been proposed to possess crucial signaling capabilities. In this study, we propose to explore the role and mechanism of βOHB in OA. Tissue staining and inflammatory factor assay were employed to evaluate the impacts of KD and βOHB on OA rats. The oxidative stress conditions in chondrocytes were induced using tert-butyl hydroperoxide (TBHP). The mechanisms were determined using the siRNA of hydroxycarboxylic acid receptor 2 (HCAR2), the antagonist of adenosine monophosphate-activated protein kinase (AMPK), and the inhibitor of mitophagy. The administration of KD demonstrated a reduction in pathological damage to cartilage, as well as a decrease in plasma levels of inflammatory factors. Furthermore, it resulted in an increase in the concentration of βOHB in the blood and synovial fluid. Invitro experiments showed that βOHB facilitated mitophagy and adenosine triphosphate production. Besides, βOHB mitigated chondrocyte senescence, inflammatory factors secretion, extracellular matrix degradation, and apoptosis induced by TBHP. Subsequent investigations indicated that the protective effects of βOHB were no longer observed following the knockdown of HCAR2, the antagonist of AMPK, or the inhibitor of mitophagy. Moreover, invivo studies suggested that βOHB played a protective role by targeting the HCAR2-AMPK-PINK1 axis. In conclusion,βOHB enhanced chondrocyte mitophagy through the HCAR2/AMPK/PINK1/Parkin pathway, offering a potential therapeutic approach for the treatment of OA.

Efficacy of cordycepin against Neospora caninum infection in vitro and in vivo

Neospora caninum (N. caninum) is an obligate intracellular Apicomplexa parasite that causes abortions in dairy cows and incurs substantial to significant economic losses in the global dairy farming industry. Cordycepin, a nucleoside antibiotic derived from Chinese medicine Cordyceps militaries, exhibits diverse biological activities. However, it remains unclear whether cordycepin possesses inhibitory effects against N. caninum infection. Therefore, this study aimed to establish both in vivo and in vitro models of N. caninum to investigate the potential impact of cordycepin against N. caninum infection. We successfully established an in vitro model of N. caninum infection in RAW264.7 cells, followed by qRT- PCR analysis to detect the content of N. caninum DNA within the cells. The effects of cordycepin on N. caninum was observed using the Giemsa method on RAW264.7, and the rate of cell infection was calculated. Cordycepin exhibited inhibitory effects on N. caninum tachyzoites in vitro, preserving cellular integrity and reducing the rate of cell infection. In mice, we established an in vivo model of N. caninum infection and detected N. caninum presence in tissues using. Real-time fluorescence quantitative PCR. Histopathological changes were observed through Hematoxylin-eosin staining. Liver function was assessed by using glutamic acid aminotransferase (ALT) and aspartic acid aminotransferase (AST) kits. Oxidative stress status was measured using catalase (CAT), malondialdehyde (MDA), and glutathione (GSH) kits. Compared with the model group, mice treated with cordycepin showed reduced clinical symptoms, increased food intake, and their body weight (P=0.0143, P=0.0068) was significantly higher than those in the model group. Furthermore, cordycepin treatment significantly alleviated hepatic cord disorders, hepatocellular swelling, detachment, and vacuolization; duodenal epithelial detachment and shortening of villi caused by N. caninum infection. Cordycepin administration reduced the increase in ALT (P=0.01, P=0.008) and AST (P<0.001) levels caused by N. caninum infection, while ameliorating hepatocyte swelling, necrosis, and detachment as well as inflammatory cell infiltration within mice liver; it also led to shortened or even disappeared duodenal villi along with and oedema of the submucosa. Analysis of oxidative stress showed that cordycepin ameliorated the damage caused by N. caninum by reducing MDA (P=0.03, P=0.02, P=0.005) and increasing CAT (P=0.004, P<0.001) and GSH (P=0.004, P<0.001) levels. In conclusion, this study reports for the first time on cordycepin's efficacy against N. caninum infection providing a potential candidate drug for neosporosis treatment.

Autophagic genes and antioxidant status during doxorubicin therapy under temperature-stressed conditions in breast cancer cells

ObjectivesAutophagy as a cellular event swings between apoptosis induction and cellular maintenance during chemotherapy. The interplay between autophagy and reactive oxygen species (ROS) remains obscure in cancer progression and treatment. This study aimed to determine the combination effect of chemotherapy and hyperthermia on cancer cell proliferation, autophagy signaling, and oxidative stress status. MethodsTo estimate the autophagic genes' role and antioxidant capacity involvement during chemotherapy, human breast cancer cell lines (MCF7 and CAL51) were exposed to a high temperature at 42 °C and treated with doxorubicin (DOX). The MTT assays were performed to determine the cell survival levels, and the autophagic gene expression levels (ATG5, LC3A, LC3B, and Beclin1) were analyzed. The intracellular TAS (total antioxidant status) and SOD (superoxide dismutase) activities were determined. ResultsThe combined effects of high temperature with chemotherapy significantly reduced cell viability and cell survival compared to cells treated with the chemotherapeutic agent DOX alone. The cell's autophagic gene activities were significantly increased after exposure to 42 °C temperature and DOX-based chemotherapy compared to the cells treated with DOX alone. It was observed that TAS and SOD activities were increased in the cell lines exposed to high temperatures with DOX compared to the cells treated with DOX alone. Increased autophagic gene expression levels and cell death were observed in response to the high temperature and DOX treatment in breast cancer cells. ConclusionThe study may provide a plausible route and treatment plan for the individual adoption of cancer chemotherapy and be developed as part of the personalized medicine protocol.

Peroxiredoxin 1 modulates oxidative stress resistance and cell apoptosis through stemness in liver cancer under non-thermal plasma treatment

The role of peroxiredoxin 1 (PRDX1), a crucial enzyme that reduces reactive oxygen and nitrogen species levels in HepG2 human hepatocellular carcinoma (HCC) cells, in the regulation of HCC cell stemness under oxidative stress and the underlying mechanisms remain largely unexplored. Here, we investigated the therapeutic potential of non-thermal plasma in targeting cancer stem cells (CSCs) in HCC, focusing on the mechanisms of resistance to oxidative stress and the role of PRDX1. By simulating oxidative stress conditions using the plasma-activated medium, we found that a reduction in PRDX1 levels resulted in a considerable increase in HepG2 cell apoptosis, suggesting that PRDX1 plays a key role in oxidative stress defense mechanisms in CSCs. Furthermore, we found that HepG2 cells had higher spheroid formation capability and increased levels of stem cell markers (CD133, c-Myc, and OCT-4), indicating strong stemness. Interestingly, PRDX1 expression was notably higher in HepG2 cells than in other HCC cell types such as Hep3B and Huh7 cells, whereas the expression levels of other PRDX family proteins (PRDX 2–6) were relatively consistent. The inhibition of PRDX1 expression and peroxidase activity by conoidin A resulted in markedly reduced stemness traits and increased cell death rate. Furthermore, in a xenograft mouse model, PRDX1 downregulation considerably inhibited the formation of solid tumors after plasma-activated medium (PAM) treatment. These findings underscore the critical role of PRDX 1 in regulating stemness and apoptosis in HCC cells under oxidative stress, highlighting PRDX1 as a promising therapeutic target for NTP-based treatment in HCC.

EnvZ/OmpR Controls Protein Expression and Modifications in Cronobacter sakazakii for Virulence and Environmental Resilience.

Cronobacter sakazakii is a notorious foodborne opportunistic pathogen, particularly affecting vulnerable populations such as premature infants, and poses significant public health challenges. This study aimed to elucidate the role of the envZ/ompR genes in environmental tolerance, pathogenicity, and protein regulation of C. sakazakii. An envZ/ompR knockout mutant was constructed and assessed for its impact on bacterial growth, virulence, environmental tolerance, and protein regulation. Results demonstrate that deletion of envZ/ompR genes leads to reduced growth rate and attenuated virulence in animal models. Additionally, the knockout strain exhibited compromised environmental tolerance, particularly in desiccation and oxidative stress conditions, along with impaired adhesion and invasion abilities in epithelial cells. Proteomic analysis revealed significant alterations in protein expression and phosphorylation patterns, highlighting potential compensatory mechanisms triggered by gene deletion. Furthermore, investigation into protein deamidation and glucose metabolism uncovered a link between envZ/ompR deletion and energy metabolism dysregulation. Interestingly, the downregulation of MalK and GrxC proteins was identified as contributing factors to altered desiccation tolerance and disrupted redox homeostasis, respectively, providing mechanistic insights into the phenotypic changes observed. Overall, this study enhances understanding of the multifaceted roles of envZ/ompR in C. sakazakii physiology and pathogenesis, shedding light on potential targets for therapeutic intervention and food safety strategies.

OXidative Stress PREDictor: A Supervised Learning Approach for Annotating Cellular Oxidative Stress States in Inflammatory Cells

Oxidative stress, characterized by an imbalance between reactive oxygen species (ROS) and antioxidants, plays a pivotal role in inflammatory responses associated with both chronic diseases and acute injuries. In this study, OXidative Stress PREDictor (OxSpred), a supervised learning model tailored to accurately annotate the oxidative stress state of innate immune cells at the single‐cell level, is introduced. Compared to the traditional gene‐set‐variation‐analysis‐based enrichment method, OxSpred demonstrates superior accuracy with an area under the receiver operating characteristic curve of 0.89 and offers interpretable embeddings with significant biological relevance. Using the predicted ROS states, precise elucidation and interpretation of the roles of novel innate immune cell subtypes can be achieved. Overall, OxSpred enhances the utility of single‐cell transcriptomic datasets by providing a robust in silico method for determining intracellular oxidative stress states, thereby enriching the understanding of innate immune cell functions during inflammation.

Differences in HDL Remodeling during Healthy Pregnancy and Pregnancy with Cardiometabolic Complications.

This study investigated the longitudinal trajectory of changes in antioxidative and anti-inflammatory high-density lipoprotein (HDL) components during healthy pregnancy and pregnancy with cardiometabolic complications. We recruited and longitudinally followed 84 women with healthy pregnancies and 46 pregnant women who developed cardiometabolic pregnancy complications (gestational diabetes mellitus and hypertensive disorders of pregnancy). Their general lipid profiles, oxidative stress status, inflammatory status, and antioxidative and anti-inflammatory HDL components were analyzed. The results of our study confirmed the expected trajectory for the routine lipid parameters. Our study results indicate more intensive oxidative stress and a higher level of inflammation in the group with complications compared with the control group. Sphingosine-1-phosphate (S1P) was significantly lower in the first trimester in the group with complications compared with the control group (p < 0.05). We did not find significant differences in the apolipoprotein A1 (Apo A1) concentrations in the first trimester between the control group and the group with complications, but in the second and third trimesters, the group with complications had significantly higher concentrations (p < 0.001, p < 0.05, respectively). The S1P, paraoxonase 1 (PON1), and serum amyloid A (SAA) concentrations were significantly lower in the group with complications in the first trimester. During the second trimester, only the SAA concentrations were identified as significantly lower in the group with complications compared with the control group, while in the third trimester, the PON1, apolipoprotein M (Apo M), and SAA concentrations were all significantly lower in the group with complications. Through a multivariate binary logistic regression analysis, the S1P concentration in the first trimester was distinguished as an HDL-associated marker independently associated with cardiometabolic pregnancy complications. In conclusion, our study results showed that HDL remodeling differs between healthy pregnancies and pregnancies with maternal cardiometabolic complications, with changed HDL composition and functionality consequently impacting its biological functionality in the latter case.

Abstract Tu123: Redox Biology of the Mitochondrial Protein mitoNEET and Ascorbate

Background: It has been proposed that mitoNEET is an Fe-S transfer/repair enzyme, playing a role under conditions of oxidative stress. mitoNEET protects mitochondria against oxidative stress in cardiomyocytes. Loss of mitoNEET is linked with age-related heart failure. Oxidized mitoNEET, [2Fe-2S] 2+ , exports Fe-S cluster from mitochondria to cytosol. Redox control of mitochondrion is essential for the proper functioning of the organelle/mitochondria. However, the molecular mechanisms involved in the redox biology of mitoNEET is not fully studied. Hypothesis: Ascorbate regulates redox reactions and Fe-S cluster transport function of mitoNEET in the mitochondria. Aims: The objective of this work is to evaluate the redox reactions between mitoNEET and ascorbate. Methods: Room temperature and low temperature (77 K) electron paramagnetic resonance (EPR) spectroscopy techniques were used to measure the oxidation of ascorbate and reduced mitoNEET, respectively. Results: EPR spectroscopic study shows that mitoNEET oxidizes ascorbate to ascorbate radical. The formation of ascorbate radical increases with increasing concentration of ascorbate. The formation of ascorbate radical is decreased in the presence of menadione. Low temperature EPR study shows that one electron reduction of mitoNEET by ascorbate. Conclusion: This study suggest that ascorbate is a substrate/cofactor for mitoNEET. Ascorbate regulates the Fe-S cluster transport function of mitoNEET. Ascorbate plays an important role in the redox biology of mitoNEET under physiological and pathophysiological conditions.

Abstract Tu146: GJA1-20k Promotes Formation of Mitochondrial Actin Cages

Introduction: GJA1-20k, an N-terminus truncated isoform of the gap junction protein Connexin 43, is stress responsive and mimics ischemia preconditioning, reducing ischemia-reperfusion (IR) injury. GJA1-20k localizes to the outer membrane of mitochondria, stabilizes actin, and mediates an actin mediated mitochondrial protection. The mechanism is not known how GJA1-20k and actin work towards mitochondrial protection. Methods: Cell-free TIRF imaging was performed to study direct interactions between actin and purified GJA1-20k. High-resolution confocal microscopy was applied to visualize GJA1-20k and actin organization around mitochondria in intact HEK cells and cell-free suspensions wherein rhodamine-labeled actin, purified GJA1-20k, and isolated mitochondria were incubated together. Results: Cell-free TIRF imaging establishes that GJA1-20k directly binds to actin , forming both actin clusters and stabilized actin filaments. As expected, live-cell imaging reveals that GJA1-20k is enriched at the mitochondrial outer membrane. The direct binding of GJA1-20k and actin results in a rich collection of actin around mitochondria, as evidenced in both live-cell imaging and cell-free suspensions containing only purified actin, GJA1-20k, and isolated mitochondria. 3D reconstruction reveals that mitochondrial localization of GJA1-20k causes formation of dense actin sheets enveloping mitochondria, which we call “mitochondrial actin cages” which appear to limit the ability of mitochondria to swell under stress conditions. Conclusions: GJA1-20k induced actin cages could be critical to GJA1-20k mediated protection against IR injury. The observed actin around mitochondria could prevent pathological mitochondrial swelling, preserving mitochondrial integrity and function in oxidative stress conditions.

Production of nutritionally active compounds from Spirulina platensis under various stress conditions

The free-floating, filamentous cyanobacteria Spirulina platensis is highly valued and in great demand worldwide for its high-value colors and phytonutrients. These compounds find use in health foods, feed, medicines, and diagnostics. The primary objective of this work was to enhance the growth of Spirulina under both oxidative and physiological stress conditions in order to maximize the synthesis of phycocyanin and carotenoid pigments. Cultures were subjected to different concentrations of hydrogen peroxide (H2O2) and sodium chloride for varying temperatures and pH levels. Under lower concentrations of H2O2 (4mM), the maximum carotenoid content was increased, but the phycocyanin content was found to be stimulated at 10mM. Moreover, the synthesis of both pigments was shown to be highest under physiological stress circumstances (40mM and 60mM NaCl concentration) and at an optimal pH of 8-9, helped by a temperature range of 25-30℃. The experimental results demonstrate that both carotenoid and phycocyanin exhibit antioxidant properties even in the presence of oxidative stress. This suggests that the aforementioned circumstances can be applied in future investigations to extract different antioxidants from S. platensis.