Is Hydrogen Peroxide a Suitable Apoptosis Inducer for All Cell Types?

LINC00894 inhibited neuron cellular apoptosis and regulated activating transcription factor 3 expression

LINC00894 may be associated with synaptic function, but its biology function in neural cells is still unknown. In this study, LINC00894 knockdown decreased the EdU incorporated into newly synthesized DNA and cell viability in MTT or CCK-8 assay in HEK-293T and BE(2)-M17 (M17) neuroblastoma cells. And LINC00894 knockdown increased cellular apoptosis in Annexin V-FITC staining, the expression of activated Caspase3 and the level of reactive oxygen species (ROS) both in HEK-293T and M17 cells. Moreover, LINC00894 also protected cells from hydrogen peroxide induced apoptosis in in vitro models. Utilizing RNA sequencing (RNA-seq) integrated with quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunoblot, we identified that LINC00894 affected activating transcription factor 3 (ATF3) expression in HEK-293T, M17, and SH-SY5Y neuroblastoma cells. Finally, we found that ectopic expression of ATF3 restored cell proliferation and inhibited cell apoptosis in LINC00894 downregulated M17 cells. While knockdown of ATF3 also significantly increased the cell viability inhibition and apoptosis promotion induced by LINC00894 knockdown in M17 cells. Our results from in vitro models revealed that LINC00894 could promote neuronal cell proliferation and inhibit cellular apoptosis by affecting ATF3 expression.

SMYD5 is a regulator of the mild hypothermia response

The mild hypothermia response (MHR) maintains organismal homeostasis during cold exposure and is thought to be critical for the neuroprotection documented with therapeutic hypothermia. To date, little is known about the transcriptional regulation of the MHR. We utilize a forward CRISPR-Cas9 mutagenesis screen to identify the histone lysine methyltransferase SMYD5 as a regulator of the MHR. SMYD5 represses the key MHR gene SP1 at euthermia. This repression correlates with temperature-dependent levels of histone H3 lysine 26 trimethylation (H3K36me3) at the SP1 locus and globally, indicating that the mammalian MHR is regulated at the level of histone modifications. We have identified 37 additional SMYD5-regulated temperature-dependent genes, suggesting a broader MHR-related role for SMYD5. Our study provides an example of how histone modifications integrate environmental cues into the genetic circuitry of mammalian cells and provides insights that may yield therapeutic avenues for neuroprotection after catastrophic events.

SMYD5 is a regulator of the mild hypothermia response

The mild hypothermia response (MHR) maintains organismal homeostasis during cold exposure and is thought to be critical for the neuroprotection documented with therapeutic hypothermia. To date, little is known about the transcriptional regulation of the MHR. We utilize a forward CRISPR-Cas9 mutagenesis screen to identify the histone lysine methyltransferase SMYD5 as a regulator of the MHR. SMYD5 represses the key MHR gene SP1 at euthermia. This repression correlates with temperature-dependent levels of H3K36me3 at the SP1-locus and globally, indicating that the mammalian MHR is regulated at the level of histone modifications. We have identified 37 additional SMYD5 regulated temperature-dependent genes, suggesting a broader MHR-related role for SMYD5. Our study provides an example of how histone modifications integrate environmental cues into the genetic circuitry of mammalian cells and provides insights that may yield therapeutic avenues for neuroprotection after catastrophic events.

n-3 enriched Fish oil diet enhanced intestinal barrier integrity in broilers after Eimeria infection

Coccidiosis caused by Eimeria spp. results in substantial economic losses in the poultry industry. The objective of this study was to investigate the effects of dietary supplementation with n-3 polyunsaturated fatty acids-enriched fish oil on growth performance, intestinal barrier integrity, and intestinal immune response of broilers challenged with Eimeria spp. A total of 576 fourteen-day-old broilers were randomly assigned in a completely randomized design with a 3 × 2 factorial arrangement, comprising 2 diets supplemented with either 5% fish oil or 5% soybean oil, and 3 Eimeria spp. infection levels: a nonchallenge control, a low dose of Eimeria challenge, and a high challenge dose. The results of the study revealed significant interactions between diet and Eimeria challenge to parameters of gut barrier integrity and feed intake. A significant interaction was observed in feed intake between 5 and 8 d postinfection (DPI), where the fish oil groups exhibited a higher amount of feed intake compared to the soybean oil diet groups after coccidiosis infection. The effects of the fish oil diet resulted in enhanced gut barrier integrity, as evidenced by a trend of decreased gastrointestinal leakage and a lower mean of small intestine lesion scores after Eimeria challenge. Additionally, significant interactions were noted between Eimeria spp. challenge and diet regarding jejunal crypt depth. The positive impact of the fish oil diet was particularly noticeable with the high Eimeria challenge dose. Overall, these findings underscore the relationship between the fish oil diet and Eimeria challenge on broiler chicken intestinal health. Dietary supplementation of fish oil has the potential to maintain small intestine barrier integrity with severe Eimeria infection conditions.

Sperm freezing damage: the role of regulated cell death

Substantial progress in research on sperm cryopreservation has occurred since the twentieth century, especially focusing on improving sperm freezing procedures and optimizing semen extenders. However, the cellular biological mechanisms of sperm freezing damage are still unclear, which greatly restricts the promotion and development of sperm cryopreservation. An essential component of sperm freezing damage is the occurrence of cell death. Considering the existence of multiple types of cell death pathways, this review discusses connections between characteristics of regulated cell death (e.g., apoptosis and ferroptosis), and accidental cell death (e.g., intracellular ice crystals) with sperm freezing damage and explores possible future research directions in this field.

Self-Assembly of Peptides as an Alluring Approach toward Cancer Treatment and Imaging

Cancer is a severe threat to humans, as it is the second leading cause of death after cardiovascular diseases and still poses the biggest challenge in the world of medicine. Due to its higher mortality rates and resistance, it requires a more focused and productive approach to provide the solution for it. Many therapies promising to deliver favorable results, such as chemotherapy and radiotherapy, have come up with more negatives than positives. Therefore, a new class of medicinal solutions and a more targeted approach is of the essence. This review highlights the alluring properties, configurations, and self-assembly of peptide molecules which benefit the traditional approach toward cancer therapy while sparing the healthy cells in the process. As targeted drug delivery systems, self-assembled peptides offer a wide spectrum of conjugation, biocompatibility, degradability-controlled responsiveness, and biomedical applications, including cancer treatment and cancer imaging.

Finding a Direct Method for a Dynamic Process: The DD (Direct and Dynamic) Cell-Tox Method

The main focus of in vitro toxicity assessment methods is to assess the viability of the cells, which is usually based on metabolism changes. Yet, when exposed to toxic substances, the cell triggers multiple signals in response. With this in mind, we have developed a promising cell-based toxicity method that observes various cell responses when exposed to toxic substances (either death, division, or remain viable). Based on the collective cell response, we observed and predicted the dynamics of the cell population to determine the toxicity of the toxicant. The method was tested with two different conformations: In the first conformation, we exposed a monoculture model of blood macrophages to UV light, hydrogen peroxide, nutrient deprivation, tetrabromobisphenol A, fatty acids, and 5-fluorouracil. In the second, we exposed a coculture liver model consisting of hepatocytes, hepatic stellate cells, Kupffer cells, and liver sinusoidal endothelial cells to rifampicin, ibuprofen, and 5-fluorouracil. The method showed good accuracy compared to established toxicity assessment methods. In addition, this approach provided more representative information on the toxic effects of the compounds, as it considers the different cellular responses induced by toxic agents.

Novel Peptide-Based Fluorescent Probe for Simultaneous Sensing of Chymotrypsin and Hydrogen Peroxide

The developed multifunctional fluorescent probe enables the simultaneous detection of chymotrypsin as a model protease and hydrogen peroxide as a representative of reactive oxygen species (ROS) in biologically relevant concentration ranges. The chymotrypsin sensing is based on the cleavage of its selectively recognizable peptide sequence and the consequent disruption of FRET between coumarin (DEAC) and fluorescein (FL). Analogously, the presence of hydrogen peroxide causes the gradual degradation of the H2O2-labile benzopyrylium-coumarin (BC) dye. Considering the fluorescence emission responses of individual chymotrypsin-peroxide probe-attached fluorophores after their excitation at 425 nm, the sole presence of either chymotrypsin (50-1000 ng/mL) or hydrogen peroxide (10-200 μM) in a sample could be unambiguously confirmed or refuted. In addition, reliable simultaneous detection and approximate quantification of both studied species in the concentration ranges of 100-1000 ng/mL and 20-200 μM for chymotrypsin and H2O2, respectively, could be performed as well. The obtained results are summarized and visualized in the graphical models.

D-Amino acids differentially trigger an inflammatory environment in vitro

Studies in vivo have demonstrated that the accumulation of D-amino acids (D-AAs) is associated with age-related diseases and increased immune activation. However, the underlying mechanism(s) of these observations are not well defined. The metabolism of D-AAs by D-amino oxidase (DAO) produces hydrogen peroxide (H2O2), a reactive oxygen species involved in several physiological processes including immune response, cell differentiation, and proliferation. Excessive levels of H2O2 contribute to oxidative stress and eventual cell death, a characteristic of age-related pathology. Here, we explored the molecular mechanisms of D-serine (D-Ser) and D-alanine (D-Ala) in human liver cancer cells, HepG2, with a focus on the production of H2O2 the downstream secretion of pro-inflammatory cytokine and chemokine, and subsequent cell death. In HepG2 cells, we demonstrated that D-Ser decreased H2O2 production and induced concentration-dependent depolarization of mitochondrial membrane potential (MMP). This was associated with the upregulation of activated NF-кB, pro-inflammatory cytokine, TNF-α, and chemokine, IL-8 secretion, and subsequent apoptosis. Conversely, D-Ala-treated cells induced H2O2 production, and were also accompanied by the upregulation of activated NF-кB, TNF-α, and IL-8, but did not cause significant apoptosis. The present study confirms the role of both D-Ser and D-Ala in inducing inflammatory responses, but each via unique activation pathways. This response was associated with apoptotic cell death only with D-Ser. Further research is required to gain a better understanding of the mechanisms underlying D-AA-induced inflammation and its downstream consequences, especially in the context of aging given the wide detection of these entities in systemic circulation.

A single chemotherapy administration induces muscle atrophy, mitochondrial alterations and apoptosis in breast cancer patients

BACKGROUND

Breast cancer patients are commonly treated with sequential administrations of epirubicin-cyclophosphamide (EC) and paclitaxel (TAX). The chronic effect of this treatment induces skeletal muscle alterations, but the specific effect of each chemotherapy agent is unknown. This study aimed to investigate the effect of EC or TAX administration on skeletal muscle homeostasis in breast cancer patients.

METHODS

Twenty early breast cancer patients undergoing EC followed by TAX chemotherapies were included. Two groups of 10 women were established and performed vastus lateralis skeletal muscle biopsies either before the first administration (pre) of EC (50 ± 14 years) or TAX (50 ± 16 years) and 4 days later (post). Mitochondrial respiratory capacity recording, reactive oxygen species production, western blotting and histological analyses were performed.

RESULTS

Decrease in muscle fibres cross-sectional area was only observed post-EC (-25%; P < 0.001), associated with a reduction in mitochondrial respiratory capacity for the complex I (CI)-linked substrate state (-32%; P = 0.001), oxidative phosphorylation (OXPHOS) by CI (-35%; P = 0.002), CI&CII (-26%; P = 0.022) and CII (-24%; P = 0.027). If H2 O2 production was unchanged post-EC, an increase was observed post-TAX for OXPHOS by CII (+25%; P = 0.022). We found a decrease in makers of mitochondrial content, as shown post-EC by a decrease in the protein levels of citrate synthase (-53%; P < 0.001) and VDAC (-39%; P < 0.001). Despite no changes in markers of mitochondrial fission, a decrease in the expression of a marker of mitochondrial inner-membrane fusion was found post-EC (OPA1; -60%; P < 0.001). We explored markers of mitophagy and found reductions post-EC in the protein levels of PINK1 (-63%; P < 0.001) and Parkin (-56%; P = 0.005), without changes post-TAX. An increasing trend in Bax protein level was found post-EC (+96%; P = 0.068) and post-TAX (+77%; P = 0.073), while the Bcl-2 level was decreased only post-EC (-52%; P = 0.007). If an increasing trend in TUNEL-positive signal was observed post-EC (+68%; P = 0.082), upregulation was highlighted post-TAX (+86%; P < 0.001), suggesting activation of the apoptosis process.

CONCLUSIONS

We demonstrated that a single administration of EC induced, in only 4 days, skeletal muscle atrophy and mitochondrial alterations in breast cancer patients. These alterations were characterized by reductions in mitochondrial function and content as well as impairment of mitochondrial dynamics and an increase in apoptosis. TAX administration did not worsen these alterations as this group had already received EC during the preceding weeks. However, it resulted in an increased apoptosis, likely in response to the increased H2 O2 production.

WNT7A promotes tumorigenesis of head and neck squamous cell carcinoma via activating FZD7/JAK1/STAT3 signaling

Wnt signaling are critical pathway involved in organ development, tumorigenesis, and cancer progression. WNT7A, a member of the Wnt family, remains poorly understood in terms of its role and the underlying molecular mechanisms it entails in head and neck squamous cell carcinoma (HNSCC). According to the Cancer Genome Atlas (TCGA), transcriptome sequencing data of HNSCC, the expression level of WNT7A in tumors was found to be higher than in adjacent normal tissues, which was validated using Real-time RT-PCR and immunohistochemistry. Unexpectedly, overexpression of WNT7A did not activate the canonical Wnt-β-catenin pathway in HNSCC. Instead, our findings suggested that WNT7A potentially activated the FZD7/JAK1/STAT3 signaling pathway, leading to enhanced cell proliferation, self-renewal, and resistance to apoptosis. Furthermore, in a patient-derived xenograft (PDX) tumor model, high expression of WNT7A and phosphorylated STAT3 was observed, which positively correlated with tumor progression. These findings underscore the significance of WNT7A in HNSCC progression and propose the targeting of key molecules within the FZD7/JAK1/STAT3 pathway as a promising strategy for precise treatment of HNSCC.

Oxygen generating biomaterials at the forefront of regenerative medicine: advances in bone regeneration

Globally, an annual count of more than two million bone transplants is conducted, with conventional treatments, including metallic implants and bone grafts, exhibiting certain limitations. In recent years, there have been significant advancements in the field of bone regeneration. Oxygen tension regulates cellular behavior, which in turn affects tissue regeneration through metabolic programming. Biomaterials with oxygen release capabilities enhance therapeutic effectiveness and reduce tissue damage from hypoxia. However, precise control over oxygen release is a significant technical challenge, despite its potential to support cellular viability and differentiation. The matrices often used to repair large-size bone defects do not supply enough oxygen to the stem cells being used in the regeneration process. Hypoxia-induced necrosis primarily occurs in the central regions of large matrices due to inadequate provision of oxygen and nutrients by the surrounding vasculature of the host tissues. Oxygen generating biomaterials (OGBs) are becoming increasingly significant in enhancing our capacity to facilitate the bone regeneration, thereby addressing the challenges posed by hypoxia or inadequate vascularization. Herein, we discussed the key role of oxygen in bone regeneration, various oxygen source materials and their mechanism of oxygen release, the fabrication techniques employed for oxygen-releasing matrices, and novel emerging approaches for oxygen delivery that hold promise for their potential application in the field of bone regeneration.

Mitochondria-targeting EGCG derivatives protect H9c2 cardiomyocytes from H2O2-induced apoptosis: design, synthesis and biological evaluation

Pathologies related to cardiovascular diseases mostly emerge as a result of oxidative stress buildup in cardiomyocytes. The heavy load of mitochondrial oxidative phosphorylation in cardiac tissues corresponds to a surge in oxidative stress leading to mitochondrial dysfunction and cellular apoptosis. Thus, scavenging the reactive oxygen species (ROS) linked to mitochondria can significantly improve cardio-protection. Epigallocatechin-3-gallate (EGCG), the major polyphenol found in green tea has been extensively studied for its profound health-beneficial activities. Herein, we designed and synthesized a series of mitochondrial-targeting EGCG derivatives, namely MitoEGCGn (n = 4, 6, 8) by incorporating triphenylphosphonium ion onto it using different linkers. MitoEGCGn were found to be non-toxic to H9c2 rat cardiomyocyte cells even at higher doses in comparison to its parent molecule EGCG. Interestingly, MitoEGCG4 and MitoEGCG6 protected the H9c2 cardiomyocyte cells from the oxidative damage induced by H2O2 whereas EGCG was found to be toxic and ineffective in protecting the cells from H2O2 damage. MitoEGCG4 and MitoEGCG6 also protected the cells from the H2O2-induced disruption of mitochondrial membrane potential as well as activation of apoptosis as revealed by pro-caspase 3 expression profile, DNA fragmentation assay, and AO/EtBr staining. Taken together, our study shows that the mitochondria targeting EGCG derivatives were able to effectively combat the H2O2-induced oxidative stress in H9c2 cardiomyocytes. They eventually augmented the mitochondrial health of cardiomyocytes by maintaining the mitochondrial function and attenuating apoptosis. Overall, MitoEGCG4 and MitoEGCG6 could provision a cardioprotective role to H9c2 cardiomyocytes at the time of oxidative insults related to mitochondrial dysfunction-associated injuries.

Complement C3 Reduces Apoptosis via Interaction with the Intrinsic Apoptotic Pathway

Myocardial ischemia/reperfusion (I/R) elicits an acute inflammatory response involving complement factors. Recently, we reported that myocardial necrosis was decreased in complement C3-/- mice after heart I/R. The current study used the same heart model to test the effect of C3 on myocardial apoptosis and investigated if C3 regulation of apoptosis occurred in human cardiomyocytes. Comparative proteomics analyses found that cytochrome c was present in the myocardial C3 complex of WT mice following I/R. Incubation of exogenous human C3 reduced apoptosis in a cell culture system of human cardiomyocytes that did not inherently express C3. In addition, human C3 inhibited the intrinsic apoptosis pathway in a cell-free apoptosis system. Finally, human pro-C3 was found to bind with an apoptotic factor, pro-caspase 3, in a cell-free system. Thus, we present firsthand evidence showing that C3 readily reduces myocardial apoptosis via interaction with the intrinsic apoptotic pathway.

Synthesis of Bis-Chalcones and Evaluation of Its Effect on Peroxide-Induced Cell Death and Lipopolysaccharide-Induced Cytokine Production

Plant secondary metabolites are important sources of biologically active compounds with wide pharmacological potentials. Among the different classes, the chalcones form integral pharmacologically active agents. Natural chalcones and bis-chalcones exhibit high antioxidant and anti-inflammatory properties in various experiments. Studies are also underway to explore more biologically active bis-chalcones by chemical synthesis of these compounds. In this study, the effects of six synthetic bis-chalcones were evaluated in intestinal epithelial cells (IEC-6); further, the anti-inflammatory potentials were studied in lipopolysaccharide-induced cytokine production in macrophages. The synthesized bis-chalcones differ from each other first of all by the nature of the aromatic cores (functional group substitution, and their position) and by the size of a central alicycle. The exposure of IEC-6 cells to peroxide radicals reduced the cell viability; however, pre-treatment with the bis-chalcones improved the cell viability in these cells. The mechanism of action was observed to be the increased levels of glutathione and antioxidant enzyme activities. Further, these bis-chalcones also inhibited the LPS-stimulation-induced inflammatory cytokine production in RAW 264.7 macrophages. Overall, the present study indicated the cytoprotective and anti-inflammatory abilities of synthetic bis-chalcones.

IMT504 protects beta cells against apoptosis and maintains beta cell identity, without modifying proliferation

We have demonstrated that oligodeoxynucleotide IMT504 promotes significant improvement in the diabetic condition in diverse animal models. Based on these results, here we evaluated whether these effects observed in vivo could be due to direct effects on β-cells. We demonstrate by immunofluorescence that IMT504 enters the cell and locates in cytoplasm where it induces GSK-3β phosphorylation that inactivates this kinase. As GSK-3β tags Pdx1 for proteasomal degradation, by inactivating GSK-3β, IMT504 induces an increase in Pdx1 protein levels, demonstrated by Western blotting. Concomitantly, an increase in Ins2 and Pdx1 gene transcription was observed, with no significant increase in insulin content or secretion. Enhanced Pdx1 is promising since it is a key transcription factor for insulin synthesis and is also described as an essential factor for the maintenance β-cell phenotype and function. Dose-dependent inhibition of H2 O2 -induced apoptosis determined by ELISA as well as decreased expression of Bax was also observed. These results were confirmed in another β-cell line, beta-TC-6 cells, in which a cytokine mix induced apoptosis that was reversed by IMT504. In addition, an inhibitor of IMT504 entrance into cells abrogated the effect IMT504. Based on these results we conclude that the β-cell recovery observed in vivo may include direct effects of IMT504 on β-cells, by maintaining their identity/phenotype and protecting them from oxidative stress and cytokine-induced apoptosis. Thus, this work positions IMT504 as a promising option in the framework of the search of new therapies for type I diabetes treatment.

Engineering Modular, Oxygen-Generating Microbeads for the In Situ Mitigation of Cellular Hypoxia

Insufficient oxygenation is a key obstacle in the design of clinically scalable tissue-engineered grafts. In this work, an oxygen-generating composite material, termed OxySite, is created through the encapsulation of calcium peroxide (CaO2 ) within polydimethylsiloxane and formulated into microbeads for ease in tissue integration. Key material parameters of reactant loading, porogen addition, microbead size, and an outer rate-limiting layer are modulated to characterize oxygen generation kinetics and their suitability for cellular applications. In silico models are developed to predict the local impact of different OxySite microbead formulations on oxygen availability within an idealized cellular implant. Promising OxySite microbead variants are subsequently coencapsulated with murine β-cells within macroencapsulation devices, resulting in improved cellular metabolic activity and function under hypoxic conditions when compared to controls. Additionally, the coinjection of optimized OxySite microbeads with murine pancreatic islets within a confined transplant site demonstrates ease of integration and improved primary cell function. These works highlight the broad translatability delivered by this new oxygen-generating biomaterial format, whereby the modularity of the material provides customization of the oxygen source to the specific needs of the cellular implant.

Oxygen-releasing biomaterials for chronic wounds breathing: From theoretical mechanism to application prospect

Chronic wounds have always been considered as "gordian knots" in medicine, in which hypoxia plays a key role in blocking healing. To address this challenge, although tissue reoxygenation therapy based on hyperbaric oxygen therapy (HBOT) has been performed clinically for several years, the bench to bedside still urges the evolution of oxygen-loading and -releasing strategies with explicit benefits and consistent outcome. The combination of various oxygen carriers with biomaterials has gained momentum as an emerging therapeutic strategy in this field, exhibiting considerable application potential. This review gives an overview of the essential relationship between hypoxia and delayed wound healing. Further, detailed characteristics, preparation methods and applications of various oxygen-releasing biomaterials (ORBMs) will be elaborated, including hemoglobin, perfluorocarbon, peroxide, and oxygen-generating microorganisms, those biomaterials are applied to load, release or generate a vast of oxygen to relieve the hypoxemia and bring the subsequent cascade effect. The pioneering papers regarding to the ORBMs practice are presented and trends toward hybrid and more precise manipulation are summarized.

LKB1 Regulates Inflammation of Fibroblast-like Synoviocytes from Patients with Rheumatoid Arthritis via AMPK-Dependent SLC7A11-NOX4-ROS Signaling

Fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) patients have increased reactive oxygen species (ROS) levels and an impaired redox balance compared with FLS from control patients. Liver kinase B1 (LKB1) plays a key role in ROS scavenging and cellular metabolism in various cancers. Here, we aimed to determine the specific mechanism of LKB1 in RA pathogenesis. FLS were obtained from RA patients (n = 10). siRNA-induced LKB1 deficiency in RA FLS increased ROS levels via NADPH oxidase 4 (NOX4) upregulation. RA FLS migration and expression of inflammatory factors, including interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-alpha (TNF-α), and vascular endothelial growth factor (VEGF), were enhanced by LKB1 deficiency. LKB1-deficient RA FLS showed increased sensitivity to oxidative stress damage caused by hydrogen peroxidase exposure. siRNA-induced solute carrier family 7 member 11 (SLC7A11) deficiency in RA FLS enhanced NOX4 and ROS expression and increased cell migration. When LKB1-deficient RA FLS were stimulated with an AMP-activated protein kinase (AMPK) activator, the LKB1-inhibition-induced cell migration significantly decreased through the restoration of SLC7A11/NOX4 expression. LKB1 regulates the AMPK-mediated SLC7A11-NOX4-ROS pathway to control cell migration and inflammation. Our data indicate that LKB1 is a key regulator of redox homeostasis in RA FLS.

Granulosa cells undergo BPA-induced apoptosis in a miR-21-independent manner

Bisphenol A (BPA) is a harmful endocrine disrupting compound that alters not only classical cellular mechanisms but also epigenetic mechanisms. Evidence suggests that BPA-induced changes in microRNA expression can explain, in part, the changes observed at both the molecular and cellular levels. BPA is toxic to granulosa cells (GCs) as it can activate apoptosis, which is known to contribute to increased follicular atresia. miR-21 is a crucial antiapoptotic regulator in GCs, yet the exact function in a BPA toxicity model remains unclear. BPA was found to induce bovine GC apoptosis through the activation of several intrinsic factors. BPA reduced live cells counts, increased late apoptosis/necrosis, increased apoptotic transcripts (BAX, BAD, BCL-2, CASP-9, HSP70), increased the BAX/Bcl-2 ratio and HSP70 at the protein level, and induced caspase-9 activity at 12 h post-exposure. miR-21 inhibition increased early apoptosis and, while it did not influence transcript levels or caspase-9 activity, it did elevate the BAX/Bcl-2 protein ratio and HSP70 in the same manner as BPA. Overall, this study shows that miR-21 plays a molecular role in regulating intrinsic mitochondrial apoptosis; however, miR-21 inhibition did not make the cells more sensitive to BPA. Therefore, apoptosis induced by BPA in bovine GCs is miR-21 independent.

Natural Melanogenesis Inhibitor, Antioxidant, and Collagen Biosynthesis Stimulator of Phytochemicals in Rice Bran and Husk Extracts from Purple Glutinous Rice (Oryza sativa L. cv. Pieisu 1 CMU) for Cosmetic Application

Oryza sativa L. cv. Pieisu 1 CMU (PES1CMU) has a high anthocyanin content in the colored bran and high phenolic content in the husk. Biologically active compounds in plants are available as dietary supplements and cosmetics. To expand the utilization of natural resources, PES1CMU will be a natural remedy for skin hyperpigmentation and aging. Cell-free tyrosinase inhibition and scavenging assays were used to screen all extracts, including PES1CMU-rice bran oil (RBO), PES1CMU-defatted rice bran (DFRB), and PES1CMU-husk (H). PES1CMU extracts were first examined in IBMX-stimulated B16 cells and H₂O₂-induced fibroblasts. The results exhibited that PES1CMU-DFRB was the most effective inhibitor of mushroom tyrosinase, intracellular melanin production (fold change of 1.11 ± 0.01), and tyrosinase activity (fold change of 1.22 ± 0.10) in IBMX-stimulated B16 cells. Particularly, PES1CMU-DFRB showed a comparable whitening effect to the standard arbutin with no significant difference (p > 0.05). Moreover, PES1CMU-DFRB and PES1CMU-H demonstrated strong scavenging activities. After accelerated cell aging caused by H₂O₂ exposure in fibroblasts, the levels of malondialdehyde production in all PES1CMU-treated fibroblasts were comparable with those of standard l-ascorbic acid (p > 0.05). Besides, PES1CMU-DFRB and PES1CMU-H treatment significantly inhibited collagen degradation against MMP-2 compared to l-ascorbic acid-treated cells (p > 0.05). PES1CMU rice-processing wastes (DFRB and H) could become potential natural sources for dermatocosmetic constituents in skin anti-aging and whitening products.

Hydrogen Peroxide Produced from Selective Phenolic Acids in Cell Culture Underlies Caco-2 Changes in Cell Proliferation Parameters

The physicochemical property of phenolic acids to generate hydrogen peroxide (H₂O₂) in cell culture media has been underreported when describing multiple biological effects in vitro. Our aim was to focus on examining the relative capacity of four common phenolic acids widely consumed in the Western diet for autoxidation potential to generate H₂O₂ during in vitro culture. Furthermore, quantifying H₂O₂ derived from different phenolic acids cultured in Dulbecco's modified Eagle's medium (DMEM) was associated with changes in cell proliferation in non-differentiated human intestinal carcinoma cells. Results showed that the different percentage losses of phenolic acids, namely, caffeic (84.78 ± 1.51), chlorogenic (37.3 ± 0.38), ferulic (1.26 ± 0.78), and gallic (100%), paralleled a relative capacity to generate H₂O₂ when present in DMEM media for 24 h. The rate and total H₂O₂ generated was dependent on both phenolic acid type and concentration (p < 0.05). Gallic acid had the greatest capacity to generate H₂O₂ in culture without the presence of cells (p < 0.05). When cultured with non-differentiated Caco-2 cells, gallic acid evoked the greatest bioactivity that included cytotoxicity, anti-proliferation, apoptosis, and nuclear condensation, respectively (p < 0.05). Corresponding treatments with cells with phenolic acids in the presence of catalase confirmed that H₂O₂ generated from phenolic acid autoxidation was involved in cell proliferation and apoptosis.

Therapeutic propensity of ginsenosides Rg1 and Rg3 in rhabdomyolysis-induced acute kidney injury and renohepatic crosstalk in rats

BACKGROUND

Ginseng is a traditional herbal medicine used for thousands of years in Southeast Asian countries because of its medicinal properties. Ginsenosides Rg1 and Rg3 have demonstrated therapeutic properties against a broad spectrum of diseases.

PURPOSE

Here in this study, we investigated the therapeutic efficacy of Rg1 and Rg3 in alleviating glycerol-induced acute kidney injury, also known as rhabdomyolysis-induced acute kidney injury (RAKI).

METHODS

AKI was induced in male Wistar rats through intramuscular injection of 10 mL/kg glycerol and simultaneous oral treatment of ginsenosides Rg1 and Rg3 for 3 days. We also evaluated the therapeutic potential of Rg1 and Rg3 on human embryonic kidney epithelial (HEK-293). Cell viability and LDH assay were performed on HEK-293 cells to evaluate the toxicity of Rg1 and Rg3. Evaluation of important kidney damage markers such as creatinine and blood urea nitrogen (BUN) was carried out at different time points from the rat serum. Histopathological analysis was performed on kidney tissues. We also performed experiments such as ELISA assay, immunohistochemistry, immunofluorescence staining, COMET assay, western blotting, TUNEL assay, and flow cytometry to obtain results.

RESULTS

Rg1 and Rg3 significantly downregulated the expression of kidney damage markers such as creatinine and BUN in a dose-dependent manner. Histopathological analysis revealed damage across the glomerulus, tubules, and collecting duct rendering the kidney dysfunctional in glycerol treatment groups. However, Rg1 and Rg3 treated groups showed a significant reduction in tubular necrosis at both 10 and 20 mg/kg. There was also a sharp downregulation of oxidative and ER stress markers. Additionally, we observed nuclear translocation of Nrf2 which were more prominent in kidney tissues. Rg1 and Rg3 were also able to mitigate apoptotic cell death in vitro and in vivo evaluated through immunofluorescence staining for p53, TUNEL assay, flow cytometry, and immunoblotting for intrinsic apoptosis markers.

CONCLUSION

In summary, we conclude that Rg1 and Rg3 exhibited natural therapeutic remedy against AKI.

Intratumoral pro-oxidants promote cancer immunotherapy by recruiting and reprogramming neutrophils to eliminate tumors

Neutrophils have recently gained recognition for their potential in the fight against cancer. Neutrophil plasticity between the N1 anti-tumor and N2 pro-tumor subtypes is now apparent, as is the ability to polarize these individual subtypes by interventions such as intratumoral injection of various agents including bacterial products or pro-oxidants. Metabolic responses and the production of reactive oxygen species (ROS) such as hydrogen peroxide act as potent chemoattractants and activators of N1 neutrophils that facilitates their recruitment and ensuing activation of a toxic respiratory burst in tumors. Greater understanding of the precise mechanism of N1 neutrophil activation, recruitment and regulation is now needed to fully exploit their anti-tumor potential against cancers both locally and at distant sites. This systematic review critically analyzes these new developments in cancer immunotherapy.

Rhabdomyolysis-induced acute kidney injury and concomitant apoptosis induction via ROS-mediated ER stress is efficaciously counteracted by epigallocatechin gallate

Rhabdomyolysis induced acute kidney injury (RIAKI) is a life-threatening condition responsible for approximately 19-58% of AKI cases worldwide. We performed an intramuscular injection of glycerol (10 mL/kg) in male wistar rats to induce AKI. Epigallocatechin gallate (EGCG) was administered for 3 consecutive days to evaluate its protective effects. We observed significant downregulation in serum creatinine, blood urea nitrogen (BUN) and LDH at different time points on EGCG treatment groups in a dose-dependent manner. Similarly, H&E staining also revealed that EGCG was able to reduce the formation of damaged tubules and tubular necrosis which was prominently spread throughout the kidney tissue of glycerol treatment group. Concomitantly, we observed upregulated inflammation, ER stress and elevated oxidative stress in the glycerol treated group only, which was significantly normalized upon EGCG treatment in both in vitro and in vivo studies. The occurrence of apoptosis in kidney tubules was found to be relatively higher in glycerol treated group and H₂O₂ treated HEK-293 cells. The results obtained after EGCG treatment revealed a significant decrease in apoptotic cell population, which was further validated by immunofluorescence staining against p53 and comet assay in HEK-293 cells and p53 IHC in kidney tissues. Western blotting also revealed a systemic downregulation of intrinsic mitochondrial apoptotic pathway markers such as bax, bcl-2, pro and cleaved caspase 3, caspase 9 and PARP1. Additionally, the results for flow cytometry analysis and TUNEL assay corroborated apoptotic equilibrium. Conclusively, we reckon EGCG as a multi-therapeutic natural product that can be used the for treatment of AKI.

Reductions in bacterial viability stimulate the production of Extra-intestinal Pathogenic Escherichia coli (ExPEC) cytoplasm-carrying Extracellular Vesicles (EVs)

Extra-intestinal Pathogenic Escherichia coli (ExPEC) is defined as an extra-intestinal foodborne pathogen, and several dominant sequence types (STs) ExPEC isolates are highly virulent, with zoonotic potential. Bacteria extracellular vesicles (EVs) carry specific subsets of molecular cargo, which affect various biological processes in bacteria and host. The mechanisms of EVs formation in ExPEC remains to be elucidated. Here, the purified EVs of ExPEC strains of different STs were isolated with ultracentrifugation processes. A comparative analysis of the strain proteomes showed that cytoplasmic proteins accounted for a relatively high proportion of the proteins among ExPEC EVs. The proportion of cytoplasm-carrying vesicles in ExPEC EVs was calculated with a simple green fluorescent protein (GFP) expression method. The RecA/LexA-dependent SOS response is a critical mediator of generation of cytoplasm-carrying EVs. The SOS response activates the expression of prophage-associated endolysins, Epel1, Epel2.1, and Epel2.2, which triggered cell lysis, increasing the production of ExPEC cytoplasm-carrying EVs. The repressor LexA controlled directly the expression of these endolysins by binding to the SOS boxes in the endolysin promoter regions. Reducing bacterial viability stimulated the production of ExPEC EVs, especially cytoplasm-carrying EVs. The imbalance in cell division caused by exposure to H₂O₂, the deletion of ftsK genes, or t⁶A synthesis defects activated the RecA/LexA-dependent SOS response, inducing the expression of endolysins, and thus increasing the proportion of cytoplasm-carrying EVs in the total ExPEC EVs. Antibiotics, which decreased bacterial viability, also increase the production of ExPEC cytoplasm-carrying EVs through the SOS response. Changes in the proportion of cytoplasm-carrying EVs affected the total DNA content of ExPEC EVs. When macrophages are exposed to a higher proportion of cytoplasm-carrying vesicles, ExPEC EVs were more cytotoxic to macrophages, accompanied with more-severe mitochondrial disruption and a higher level of induced intrinsic apoptosis. In summary, we offered comprehensive insight into the proteome analysis of ExPEC EVs. This study demonstrated the novel formation mechanisms of E. coli cytoplasm-carrying EVs.

Bacteria can release extracellular vesicles (EVs) into the extracellular environment. Bacterial EVs are primarily composed of protein, DNA, RNA, lipopolysaccharide (LPS), and diverse metabolite molecules. The molecular cargoes of EVs are critical for the interaction between microbes and their hosts, and affected various host biological processes. However, the mechanisms underlying the biogenesis of bacterial EVs had not been fully clarified in extra-intestinal pathogenic Escherichia coli (ExPEC). In this study, we demonstrated ExPEC EVs contained at least three types of vesicles, including outer membrane vesicles (OMVs), outer-inner membrane vesicles (OIMVs), and explosive outer membrane vesicles (EOMVs). Our results systematically identified important factors affecting the production of ExPEC cytoplasm-carrying EVs, especially EOMVs. A reduction in bacterial viability activated the RecA/LexA-dependent SOS response, inducing the expression of endolysins, which increased the production of ExPEC cytoplasm-carrying EVs. This increase in the proportion of cytoplasm-carrying EVs increased the cytotoxicity of EVs. It was noteworthy that antibiotics increased the production of ExPEC EVs, especially the numbers of cytoplasm-carrying EVs, which in turn increased EV cytotoxicity, suggesting that the treatment of infections of multidrug-resistant strains infection with antibiotics might cause greater host damage. Our study should improve the prevention and treatment of ExPEC infections.

Protein Kinase N2 Reduces Hydrogen Peroxide-inducedDamage and Apoptosis in PC12 Cells by AntiOxidative Stress and Activation of the mTOR Pathway

Objective

To investigate the role and mechanism of protein kinase N2 (PKN2) in hydrogen peroxide (H₂O₂)-induced injury of PC12 cells.

Method

s. PC12 cells were transfected with lentivirus to knock down or overexpress PKN2 and then were treated with 300 μM H₂O₂ to establish a cell model of oxidative stress injury. The cell viability of PC12 cells in each group was determined by the CCK-8 method. Biochemical assays were used to measure reactive oxygen species (ROS), malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activity. Western blot was used to detect the protein expressions of PKN2, caspase-3, cleaved-caspase-3, PARP, cleaved-PARP, p-mTOR, and mTOR in PC12 cells in each group.

Results

H₂O₂ treatment could significantly reduce PC12 cell viability and promote cell apoptosis and oxidative stress. PKN2 overexpression inhibited H₂O₂-induced apoptosis and oxidation damage by increasing PC12 cell viability, SOD activity, and p-mTOR protein expression, reducing intracellular ROS and MDA levels, and cleaved-caspase-3 and cleaved-PARP protein expression.

Conclusion

PKN2 overexpression can alleviate H₂O₂-induced oxidative stress injury and apoptosis in PC12 cells by activating the mTOR pathway.

A Simple Assay for the Detection of Late-Stage Apoptosis Features in Saccharomyces cerevisiae

Unicellular eukaryotic organisms such as yeast and protozoa serve as useful models for studying the impact of chemicals on cell physiology, cellular growth, and genome duplication. The yeast Saccharomyces cerevisiae has been widely used to assess apoptosis induced by chemicals due to its genetic tractability, ease of evaluation, and readily available impact assessment tools. Apoptosis in S. cerevisiae is characterized by many features, including increased cell death, loss of membrane integrity, release of caspases, chromatin condensation, and nuclear fragmentation, which are similar to the ones observed in mammalian cells. Current methods of apoptosis assessment typically require specialized equipment and reagents, which limits wide adoption. Here, we describe a rapid, inexpensive, and easy-to-perform assay in yeast for the analysis of late-stage apoptotic features in cells treated with a chemical. We describe a protocol for assessing loss of cell survival and changes in the nucleus. We demonstrate the approach by using acetic acid and hydrogen peroxide as test chemicals. This assay for the study of late-stage apoptotic features in S. cerevisiae can be performed reliably and rapidly by any laboratory with basic equipment and may be extended for studying apoptosis in similar single-cell organisms after treatment with toxicological agents. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Culture of Saccharomyces cerevisiae, treatment with acetic acid or hydrogen peroxide, and semi-quantitative growth assay Basic Protocol 2: DAPI staining and fluorescence microscopy for the assessment of change in nucleus-to-cytoplasm ratio and nuclear integrity.

Mitigating toxicity of acetamiprid removal techniques - Fe modified zeolites in focus

All remediation pathways in aqueous solutions come down to three dominant ones - physical, chemical, and combinations thereof. Materials proposed for adsorption and oxidative degradation can induce positive or negative effects on cells compared to the pollutants themselves. Present research deals with the effects different methods for pesticide remediation have and how they impact cytotoxicity. With this particular intention, Fe-modified zeolites (obtained via citrate/oxalate complexes) of three zeotypes (MFI, BEA and FAU) were prepared and tested as adsorbents and Fenton catalysts for the removal of the acetamiprid pesticide. The materials are characterized by AFM, FTIR spectroscopy and ICP-OES. A different effect of the zeolite framework and modification route was found among the samples, which leads to pronounced adsorption (FAU), efficient Fenton degradation (MFI) or synergistic effect of both mechanisms (BEA). The cytotoxic effects of acetamiprid in the presence of zeolites, in pristine and modified forms, were tested on the MRC-5 human fibroblast cell line. A complete survey of the toxicity effect behind different pesticide removal methods is presented. Since neither adsorption nor catalytic degradation is the best option for pesticide removal, the focus is shifted to a combination of these methods, which proved to be optimal for pesticide toxicity reduction.

N-trans-feruloyltyramine Protects Human Neuroblastoma SK-N-SH Cell Line Against H2O2-Induced Cytotoxicity

Excessive accumulation of reactive oxygen species (ROS) has been regarded as a major contributor of pathogenesis in neurodegenerative diseases. N- trans-feruloyltyramine (NTF), an alkaloid isolated from several plants, has demonstrated an ability to be a potent antioxidant. In this study, the antioxidative and anti-apoptotic properties of NTF extracted from the stems of Polyalthia suberosa were investigated in the human neuroblastoma cell line SK-N-SH. NTF at concentrations ranging from 10 µM to 500 µM were not toxic to cells and reduced intracellular ROS levels significantly. Furthermore, pre-treatment of NTF significantly decreased H2O2-induced ROS generation and attenuated H2O2-mediated cytotoxicity. An increase in the expression of Bax and activated caspase-3 and reduction of Bcl-2 mediated by H2O2 was reversed by pre-treating the cells with 100 µM NTF. Likewise, NTF suppressed the increase of caspase-3 activity induced by H2O2. In conclusion, the findings reveal that NTF improves H2O2-induced intracellular ROS generation and decreases apoptosis. These protective effects of NTF could be useful for oxidative stress-related neurodegenerative conditions.

A Promising Method for the Determination of Cell Viability: The Membrane Potential Cell Viability Assay

Determining the viability of cells is fraught with many uncertainties. It is often difficult to determine whether a cell is still alive, approaching the point of no return, or dead. Today, there are many methods for determining cell viability. Most rely on an indirect determination of cell death (metabolism, molecular transport, and leakage, to name a few). In contrast, we have developed a promising novel method for a “direct” determination of cell viability. The potential method assesses cell membrane integrity (which is essential for all viable cells) by measuring the electrical potential of the cell membrane. To test the assay, we chose two different cell types, blood macrophages (TLT) and breast cancer epithelial cells (MCF 7). We exposed them to seven different toxic scenarios (arsenic (V), UV light, hydrogen peroxide, nutrient starvation, Tetrabromobisphenol A, fatty acids, and 5-fluorouracil) to induce different cell death pathways. Under controlled test conditions, the assay showed good accuracy when comparing the toxicity assessment with well-established methods. Moreover, the method showed compatibility with live cell imaging. Although we know that further studies are needed to confirm the performance of the assay in other situations, the results obtained are promising for their wider application in the future.

Chitosan-Coated Selenium Nanoparticles Attenuate PRRSV Replication and ROS/JNK-Mediated Apoptosis in vitro

Introduction

Porcine reproductive and respiratory syndrome virus (PRRSV) is a highly prevalent and endemic swine pathogen that causes significant economic losses to the global swine industry. Selenium nanoparticles (SeNPs) have attracted increasing attention in the biomedical field, given their antiviral effects. This study aimed to investigate the inhibitory effect of chitosan-coated SeNPs (CS-SeNPs) on PRRSV replication.

Methods

In this study, CS-SeNPs were synthesized by chemical reduction and characterized by assessing the morphology, size distribution, zeta potential, and element composition. Marc-145 cells were infected with r-PRRSV-EGFP (0.1 MOI) and inoculated with CS-SeNPs (10 μM). Subsequently, the concentrations of hydrogen peroxide (H₂O₂) and glutathione (GSH), and glutathione peroxidase (GSH-Px) activity were measured using specific commercial assay kits. ORF5 RNA expression, viral titer, and nucleocapsid (N) protein expression were assessed using qRT-PCR, TCID₅₀, and Western blot. ROS generation, apoptosis rates, and JNK /caspase-3/PARP protein expression were evaluated using dihydroethidium staining, flow cytometry, and Western blot.

Results

The results showed that CS-SeNPs treatment significantly suppressed oxidative stress induced by r-PRRSV-EGFP infection by increasing GSH-Px activity, promoting GSH production, and inhibiting H₂O₂ synthesis. CS-SeNPs treatment significantly inhibited ORF5 gene expression, viral titers, and N protein of r-PRRSV-EGFP at 24 and 48 hours post-infection (hpi) in Marc-145 cells. The increase in apoptosis rates induced by r-PRRSV-EGFP infection was significantly decreased by CS-SeNPs inoculation through inhibiting ROS generation, JNK phosphorylation levels, and cleavage of caspase-3 and PARP mainly at 48 hpi.

Conclusion

These results demonstrated that CS-SeNPs suppress PRRSV-induced apoptosis in Marc-145 cells via the ROS/JNK signaling pathway, thereby inhibiting PRRSV replication, which suggested the potential antiviral activity of CS-SeNPs that deserves further investigation for clinical applications.

Human Microglia Extracellular Vesicles Derived from Different Microglia Cell Lines: Similarities and Differences

Microglial cells are a component of the innate immune system in the brain that support cell-to-cell communication via secreted molecules and extracellular vesicles (EVs). EVs can be divided into two major populations: large (LEVs) and small (SEVs) EVs, carrying different mediators, such as proteins, lipids, and miRNAs. The microglia EVs cargo crucially reflects the status of parental cells and can lead to both beneficial and detrimental effects in many physiopathological states. Herein, a workflow for the extraction and characterization of SEVs and LEVs from human C20 and HMC3 microglia cell lines derived, respectively, from adult and embryonic microglia is reported. EVs were gathered from the culture media of the two cell lines by sequential ultracentrifugation steps and their biochemical and biophysical properties were analyzed by Western blot, transmission electron microscopy, and dynamic light scattering. Although the C20- and HMC3-derived EVs shared several common features, C20-derived EVs were slightly lower in number and more polydispersed. Interestingly, C20- but not HMC3-SEVs were able to interfere with the proliferation of U87 glioblastoma cells. This correlated with the different relative levels of eight miRNAs involved in neuroinflammation and tumor progression in the C20- and HMC3-derived EVs, which in turn reflected a different basal activation state of the two cell types. Our data fill a gap in the community of microglia EVs, in which the preparations from human cells have been poorly characterized so far. Furthermore, these results shed light on both the differences and similarities of EVs extracted from different human microglia cell models, underlining the need to better characterize the features and biological effects of EVs for therein useful and correct application.

Extracellular Particles as Carriers of Cholesterol Not Associated with Lipoproteins

Exosomes and exomeres are the smallest microparticles ranging from 20 to 130 nm in diameter. They are found in almost all biological fluids. Exosomes and exomeres are of considerable interest since they can be involved in intercellular signaling and are biological markers of the state of cells, which can be used for diagnostics. The nomenclature of exosomes remains poorly developed. Most researchers try to classify them based on the mode of formation, physicochemical characteristics, and the presence of tetrasporin markers CD9, CD63, and CD81. The data presented in this work show that although exomeres carry tetrasporin biomarkers, they differ from exosomes strongly in lipid composition, especially in cholesterol content. The production of exomeres by cells is associated with the synthesis of cholesterol in cells and is expressed or suppressed by regulators of the synthesis of mevalonate, an intermediate product of cholesterol metabolism. In addition, the work shows that the concentration of extracellular particles in the body correlates with the concentration of cholesterol in the plasma, but weakly correlates with the concentration of cholesterol in lipoproteins. This suggests that not all plasma cholesterol is associated with lipoproteins, as previously thought.

A non-enzymatic electrochemical hydrogen peroxide sensor based on copper oxide nanostructures

This article describes the synthesis of nanostructured copper oxide on copper wires and its application for the detection of hydrogen peroxide. Copper oxide petal nanostructures were obtained by a one-step hydrothermal oxidation method. The resulting coating is uniform and dense and shows good adhesion to the wire surface. Structure, surface, and composition of the obtained samples were studied using field-emission scanning electron microscopy along with energy-dispersive spectroscopy and X-ray diffractometry. The resulting nanostructured samples were used for electrochemical determination of the H₂O₂ content in a 0.1 M NaOH buffer solution using cyclic voltammetry, differential pulse voltammetry, and i-t measurements. A good linear relationship between the peak current and the concentration of H₂O₂ in the range from 10 to 1800 μM was obtained. The sensitivity of the obtained CuO electrode is 439.19 μA·mM^-1. The calculated limit of detection is 1.34 μM, assuming a signal-to-noise ratio of 3. The investigation of the system for sensitivity to interference showed that the most common interfering substances, that is, ascorbic acid, uric acid, dopamine, NaCl, glucose, and acetaminophen, do not affect the electrochemical response. The real milk sample test showed a high recovery rate (more than 95%). According to the obtained results, this sensor is suitable for practical use for the qualitative detection of H₂O₂ in real samples, as well as for the quantitative determination of its concentration.

Characterization and identification of cell death dynamics by quantitative phase imaging

SIGNIFICANCE

Investigating cell death dynamics at the single-cell level plays an essential role in biological research. Quantitative phase imaging (QPI), a label-free method without adverse effects of exogenous labels, has been widely used to image many types of cells under various conditions. However, the dynamics of QPI features during cell death have not been thoroughly characterized.

AIM

We aim to develop a label-free technique to quantitatively characterize single-cell dynamics of cellular morphology and intracellular mass distribution of cells undergoing apoptosis and necrosis.

APPROACH

QPI was used to capture time-lapse phase images of apoptotic, necrotic, and normal cells. The dynamics of morphological and QPI features during cell death were fitted by a sigmoid function to quantify both the extent and rate of changes.

RESULTS

The two types of cell death mainly differed from normal cells in the lower phase of the central region and differed from each other in the sharp nuclear boundary shown in apoptotic cells.

CONCLUSIONS

The proposed method characterizes the dynamics of cellular morphology and intracellular mass distributions, which could be applied to studying cells undergoing state transition such as drug response.

Ferroptosis as a Novel Determinant of β-Cell Death in Diabetic Conditions

The main pathological hallmark of diabetes is the loss of functional β-cells. Among several types of β-cell death in diabetes, the involvement of ferroptosis remains elusive. Therefore, we investigated the potential of diabetes-mimicking factors: high glucose (HG), proinflammatory cytokines, hydrogen peroxide (H₂O₂), or diabetogenic agent streptozotocin (STZ) to induce ferroptosis of β-cells in vitro. Furthermore, we tested the contribution of ferroptosis to injury of pancreatic islets in an STZ-induced in vivo diabetic model. All in vitro treatments increased loss of Rin-5F cells along with the accumulation of reactive oxygen species, lipid peroxides and iron, inactivation of NF-E2-related factor 2 (Nrf2), and decrease in glutathione peroxidase 4 expression and mitochondrial membrane potential (MMP). Ferrostatin 1 (Fer-1), ferroptosis inhibitor, diminished the above-stated effects and rescued cells from death in case of HG, STZ, and H₂O₂ treatments, while failed to increase MMP and to attenuate cell death after the cytokines' treatment. Moreover, Fer-1 protected pancreatic islets from STZ-induced injury in diabetic in vivo model, since it decreased infiltration of macrophages and accumulation of lipid peroxides and increased the population of insulin-positive cells. Such results revealed differences between diabetogenic stimuli in determining the destiny of β-cells, emerging HG, H₂O₂, and STZ, but not cytokines, as contributing factors to ferroptosis and shed new light on an antidiabetic strategy based on Nrf2 activation. Thus, targeting ferroptosis in diabetes might be a promising new approach for preservation of the β-cell population. Our results obtained from in vivo study strongly justify this approach.

The effects of mouthwashes in human gingiva epithelial progenitor (HGEPp) cells

OBJECTIVES

The gingiva epithelium accounts for a significant proportion of the surface around the tooth. An inflammatory reaction occurs in the presence of bacterial biofilm, adhesion is reduced, and the depth of the sulcus gingivalis increases. The most common antiseptic agents in oral rinses are chlorhexidine digluconate (CHX) and cetylpyridinium chloride. We examined long-lasting effects of residual concentrations of eight commercially available rinses. Our main goals were (i) to analyze the effect of different chemical compositions on cell proliferation, (ii) to examine apoptosis, and (iii) cell morphology on human epithelial progenitor cell line (HGEPp).

MATERIALS AND METHODS

Cell proliferation was measured in a real-time system (0-48 h) by impedimetry (xCELLigence). Apoptosis was measured with labeled Annexin-V (BD-FACScalibur).

RESULTS

Changes in proliferation were measured at certain concentrations: (i) H₂O₂ proved to be cytotoxic at almost all concentrations; (ii) low concentrations of CHX (0.0001%; 0.0003%) were proliferation inducers, while higher concentrations were cytotoxic; (iii) for ClO₂, advantageous proliferative effect was observed over a broad concentration range (0.06-6 ppm). In mouthwashes, additives in the formulation (e.g., allantoin) appeared to influence cellular responses positively. Apoptosis marker assay results suggested a low-level activation by the tested agents.

CONCLUSIONS

Mouthwashes and their reference compounds proved to have concentration-dependent cytotoxic effects on human gingival epithelial cells.

CLINICAL RELEVANCE

A better understanding of the effects of mouthwashes and their reference compounds is particularly important. These concentration-dependent effects (cytotoxic or proliferation inducing) interfere with human cells physiology while being used in the fight against the pathogenic flora.

Intrinsically High Capacity of Animal Cells From a Symbiotic Cnidarian to Deal With Pro-Oxidative Conditions

The cnidarian-dinoflagellate symbiosis is a mutualistic intracellular association based on the photosynthetic activity of the endosymbiont. This relationship involves significant constraints and requires co-evolution processes, such as an extensive capacity of the holobiont to counteract pro-oxidative conditions induced by hyperoxia generated during photosynthesis. In this study, we analyzed the capacity of Anemonia viridis cells to deal with pro-oxidative conditions by in vivo and in vitro approaches. Whole specimens and animal primary cell cultures were submitted to 200 and 500 μM of H₂O₂ during 7 days. Then, we monitored global health parameters (symbiotic state, viability, and cell growth) and stress biomarkers (global antioxidant capacity, oxidative protein damages, and protein ubiquitination). In animal primary cell cultures, the intracellular reactive oxygen species (ROS) levels were also evaluated under H₂O₂ treatments. At the whole organism scale, both H₂O₂ concentrations didn’t affect the survival and animal tissues exhibited a high resistance to H₂O₂ treatments. Moreover, no bleaching has been observed, even at high H₂O₂ concentration and after long exposure (7 days). Although, the community has suggested the role of ROS as the cause of bleaching, our results indicating the absence of bleaching under high H₂O₂ concentration may exculpate this specific ROS from being involved in the molecular processes inducing bleaching. However, counterintuitively, the symbiont compartment appeared sensitive to an H₂O₂ burst as it displayed oxidative protein damages, despite an enhancement of antioxidant capacity. The in vitro assays allowed highlighting an intrinsic high capacity of isolated animal cells to deal with pro-oxidative conditions, although we observed differences on tolerance between H₂O₂ treatments. The 200 μM H₂O₂ concentration appeared to correspond to the tolerance threshold of animal cells. Indeed, no disequilibrium on redox state was observed and only a cell growth decrease was measured. Contrarily, the 500 μM H₂O₂ concentration induced a stress state, characterized by a cell viability decrease from 1 day and a drastic cell growth arrest after 7 days leading to an uncomplete recovery after treatment. In conclusion, this study highlights the overall high capacity of cnidarian cells to cope with H₂O₂ and opens new perspective to investigate the molecular mechanisms involved in this peculiar resistance.

Chemogenetic approaches to dissect the role of H2O2 in redox-dependent pathways using genetically encoded biosensors

Chemogenetic tools are recombinant enzymes that can be targeted to specific organelles and tissues. The provision or removal of the enzyme substrate permits control of its biochemical activities. Yeast-derived enzyme D-amino acid oxidase (DAAO) represents the first of its kind for a substrate-based chemogenetic approach to modulate H2O2 concentrations within cells. Combining these powerful enzymes with multiparametric imaging methods exploiting genetically encoded biosensors has opened new lines of investigations in life sciences. In recent years, the chemogenetic DAAO approach has proven beneficial to establish a new role for (patho)physiological oxidative stress on redox-dependent signaling and metabolic pathways in cultured cells and animal model systems. This mini-review covers established or emerging methods and assesses newer approaches exploiting chemogenetic tools combined with genetically encoded biosensors.

Development of a Perfusion Reactor for Intervertebral Disk Regeneration

A tissue-engineered biological disk replacement has been proposed as a promising approach for the treatment of degenerative disk disease. A perfusion bioreactor would be a logical consideration to facilitate this scale-up as such reactors have been shown to improve nutrient delivery and provide beneficial mechanical forces that support the cultivation of large three-dimensional constructs. It was hypothesized that perfusion culture of tissue-engineered intervertebral disk (IVD) tissues would be capable of generating outer annulus fibrosus (oAF) and nucleus pulposus (NP) tissues comparable with established spinner reactor or static cultures, respectively, without compromising cellular viability, nutrient delivery, and tissue formation. In this study, the perfusion grown oAF and NP tissues did not show a significant difference in extracellular matrix (ECM) quantity or cellular phenotype when compared with their control conditions. In addition, they maintained cellular viability at the center core of the tissues and received enhanced diffusion of medium throughout the tissue when compared with static conditions. This study lays the groundwork for future studies to grow an entire IVD tissue to a physiologically relevant size.

On the Problem of Optimal Microbiological Decontamination of Air Environment and Surfaces

Modern civilization, providing economic and social progress, at the same time objectively creates—sometimes close to ideal—conditions for the spread of various infections. The catastrophic consequences of the SARS-CoV-2 pandemic clearly indicate that homo sapiens appeared to be unable to effectively resist the onslaught of the coronavirus. The purpose of this publication is an attempt to fill the gap in the development of effective methods and means for microbiological decontamination that are optimal in terms of critical parameters. The observational data indicate that a significant number of SARS-CoV-2 coronavirus infections occur by air without a direct contact with the source, including over a long time interval. Precipitation helps to cleanse the air from pollutants and viruses, reducing noncontact contamination, which additionally brings up to date the problem of optimal microbiological decontamination of the air environment and surfaces. A thermodynamic approach has been used to optimize microbiological sterilization. It is shown that irreversible chemical oxidation reactions are the shortest way to achieve sterility, and they are capable of providing high reliability of decontamination. It has been established that oxygen is an optimal oxidant, including from the point of view of ecology, since its reactive forms harmoniously fit into natural exchange cycles. The optimal method for obtaining reactive oxygen species for disinfection is the use of low-temperature (“cold”) plasma, which provides the energy-efficient generation of oxidative reactive forms: atomic oxygen (O), ozone (O₃), hydroxyl radical (^•OH), hydrogen peroxide (H₂O₂), superoxide (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{O}}_{2}^{ - }$$\end{document}), and singlet oxygen O₂(a¹Δ_g). Due to a short lifetime for most of the above forms outside the plasma applicator, objects remote from the plasma generator should be sterilized with ozone (O₃), the minimum lifetime of which is quite long. It has been substantiated that the microwave method of generating oxygen plasma is optimal for energy-efficient ozone production. A modular principle of generation is proposed for varying the productivity of ozone-generating units over a wide range. The module has been developed on the basis of an adapted serial microwave oven, in which a non-self-sustaining microwave discharge is maintained thanks to ionizers (igniters), including those based on radiating radionuclides-emitters. In case of massive contamination of surfaces, it is advisable—in addition to ozone (O₃) air disinfecting—to use aqueous solutions of hydrogen peroxide (H₂O₂). It is essential that these reactive oxygen species for disinfecting objects remote from the plasma generator are highly efficient and, at the same time, environmentally neutral. Reliable and affordable personal protective equipment is proposed for activities in zones of increased ozone concentration. The considered optimal means of disinfection can be applicable not only in medicine but also adapted for numerous practices in agriculture, industry, and everyday life.

Cardioprotective Effects of Glucagon-like Peptide-1 (9-36) Against Oxidative Injury in H9c2 Cardiomyoblasts: Potential Role of the PI3K/Akt/NOS Pathway

ABSTRACT

Glucagon-like peptide (GLP)-1(7-36), a major active form of GLP-1 hormone, is rapidly cleaved by dipeptidyl peptidase-4 to generate a truncated metabolite, GLP-1(9-36) which has a low affinity for GLP-1 receptor (GLP-1R). GLP-1(7-36) has been shown to have protective effects on cardiovascular system through GLP-1R-dependent pathway. Nevertheless, the cardioprotective effects of GLP-1(9-36) have not fully understood. The present study investigated the effects of GLP-1(9-36), including its underlying mechanisms against oxidative stress and apoptosis in H9c2 cells. Here, we reported that GLP-1(9-36) protects H9c2 cardiomyoblasts from hydrogen peroxide (H2O2)-induced oxidative stress by promoting the synthesis of antioxidant enzymes, glutathione peroxidase-1, catalase, and heme oxygenase-1. In addition, treatment with GLP-1(9-36) suppressed H2O2-induced apoptosis by attenuating caspase-3 activity and upregulating antiapoptotic proteins, Bcl-2 and Bcl-xL. These protective effects of GLP-1(9-36) are attenuated by blockade of PI3K-mediated Akt phosphorylation and prevention of nitric oxide synthase-induced nitric oxide production. Thus, GLP-1(9-36) represents the potential therapeutic target for prevention of oxidative stress and apoptosis in the heart via PI3K/Akt/nitric oxide synthase signaling pathway.

Hydrogen Peroxide and Amyotrophic Lateral Sclerosis: From Biochemistry to Pathophysiology

Free radicals are unstable chemical reactive species produced during Redox dyshomeostasis (RDH) inside living cells and are implicated in the pathogenesis of various neurodegenerative diseases. One of the most complicated and life-threatening motor neurodegenerative diseases (MND) is amyotrophic lateral sclerosis (ALS) because of the poor understanding of its pathophysiology and absence of an effective treatment for its cure. During the last 25 years, researchers around the globe have focused their interest on copper/zinc superoxide dismutase (Cu/Zn SOD, SOD1) protein after the landmark discovery of mutant SOD1 (mSOD1) gene as a risk factor for ALS. Substantial evidence suggests that toxic gain of function due to redox disturbance caused by reactive oxygen species (ROS) changes the biophysical properties of native SOD1 protein thus, instigating its fibrillization and misfolding. These abnormal misfolding aggregates or inclusions of SOD1 play a role in the pathogenesis of both forms of ALS, i.e., Sporadic ALS (sALS) and familial ALS (fALS). However, what leads to a decrease in the stability and misfolding of SOD1 is still in question and our scientific knowledge is scarce. A large number of studies have been conducted in this area to explore the biochemical mechanistic pathway of SOD1 aggregation. Several studies, over the past two decades, have shown that the SOD1-catalyzed biochemical reaction product hydrogen peroxide (H₂O₂) at a pathological concentration act as a substrate to trigger the misfolding trajectories and toxicity of SOD1 in the pathogenesis of ALS. These toxic aggregates of SOD1 also cause aberrant localization of TAR-DNA binding protein 43 (TDP-43), which is characteristic of neuronal cytoplasmic inclusions (NCI) found in ALS. Here in this review, we present the evidence implicating the pivotal role of H₂O₂ in modulating the toxicity of SOD1 in the pathophysiology of the incurable and highly complex disease ALS. Also, highlighting the role of H₂O₂ in ALS, we believe will encourage scientists to target pathological concentrations of H₂O₂ thereby halting the misfolding of SOD1.

Human Cytomegalovirus miR-UL70-3p Downregulates the H2O2-Induced Apoptosis by Targeting the Modulator of Apoptosis-1 (MOAP1)

Human Cytomegalovirus (HCMV) is a prototypic beta herpesvirus, causing persistent infections in humans. There are medications that are used to treat the symptoms; however, there is no cure yet. Thus, understanding the molecular mechanisms of HCMV replication and its persistence may reveal new prevention strategies. HCMV evasive strategies on the antiviral responses of the human host largely rely on its significant portion of genome. Numerous studies have highlighted the importance of miRNA-mediated regulation of apoptosis, which is an innate immune mechanism that eradicates virus-infected cells. In this study, we explore the antiapoptotic role of hcmv-miR-UL70-3p in HEK293T cells. We establish that hcmv-miR-UL70-3p targets the proapoptotic gene Modulator of Apoptosis-1 (MOAP1) through interaction with its 3'UTR region of mRNA. The ectopic expression of hcmv-miR-UL70-3p mimic significantly downregulates the H₂O₂-induced apoptosis through the translational repression of MOAP1. Silencing of MOAP1 through siRNA also inhibits the H₂O₂-induced apoptosis, which further supports the hcmv-miR-UL70-3p mediated antiapoptotic effect by regulating MOAP1 expression. These results uncover a role for hcmv-miR-UL70-3p and its target MOAP1 in regulating apoptosis.

A Novel Method of Mouse RPE Explant Culture and Effective Introduction of Transgenes Using Adenoviral Transduction for In Vitro Studies in AMD

Degeneration of retinal pigment epithelium (RPE) is one of the most critical phenotypic changes of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly. While cultured polarized RPE cells with original properties are valuable in in vitro models to study RPE biology and the consequences of genetic and/or pharmacological manipulations, the procedure to establish mouse primary PRE cell culture or pluripotent stem cell-derived RPE cells is time-consuming and yields a limited number of cells. Thus, establishing a mouse in situ RPE culture system is highly desirable. Here we describe a novel and efficient method for RPE explant culture that allows for obtaining biologically relevant RPE cells in situ. These RPE explants (herein referred to as RPE flatmounts) are viable in culture for at least 7 days, can be efficiently transduced with adenoviral constructs, and/or treated with a variety of drugs/chemicals followed by downstream analysis of the signaling pathways/biological processes of interest, such as assessment of the autophagy flux, inflammatory response, and receptor tyrosine kinases stimulation. This method of RPE explant culture is highly beneficial for pharmacological and mechanistic studies in the field of RPE biology and AMD research.

Induction of Constitutive Androstane Receptor during the Development of Oxidative Stress

We studied the effect of 3-, 24-, and 72-h exposure to H₂O₂ in concentrations of 0.1-100.0 μM on the level of constitutive androstane receptor in Caco-2 cells. It was shown that 3- and 24-h incubation with Н₂О₂ in all concentrations had no effect on the level of constitutive androstane receptors. Increasing the incubation time to 72 h led to an increase in the level of constitutive androstane receptor at H₂O₂ concentrations of 5, 10, and 50 μM and to a decrease at a concentration of 100 μM. Antioxidant glutathione (1 mM) in parallel to the prooxidant neutralized these changes.

The Tardigrade Damage Suppressor Protein Modulates Transcription Factor and DNA Repair Genes in Human Cells Treated with Hydroxyl Radicals and UV-C

Simple Summary

The Ramazzottius varieornatus is known to be the most resilient invertebrate on Earth. Belonging to the phylum of Tardigrada, it can live in any habitat, from the deep sea to various terrestrial environments, surviving in extreme temperatures, severe dryness or air deprivation. This exceptional tolerance to extreme conditions is attributable to the Dsup protein, which is able to bind and “protect” the DNA of this micro-animal, allowing it to survive where most other forms of life would quickly die. By introducing Dsup in human cell cultures, we investigated how this protein operates in response to two different extreme conditions: oxidative stress and ultraviolet (UV) irradiation. We learned that Dsup increases cell survival by triggering significantly different cellular mechanisms. In cells treated with hydrogen peroxide, Dsup “physically” protects DNA and activates several detoxification pathways aimed to remove intracellular free radicals. In contrast to this, a direct protection of DNA is not exerted by Dsup after UV irradiation, but the protein seems to activate mechanisms of DNA damage repair more efficiently, promoting faster cell recovery and survival. Even though further studies are required, understanding the mechanisms associated with Dsup resistance to cell damage may represent an important benefit for humans and plants.

Abstract

The Ramazzottius varieornatus tardigrade is an extremotolerant terrestrial invertebrate with a length of 0.1–1.0 mm. These small animals show an extraordinary tolerance to extreme conditions such as high pressure, irradiation, chemicals and dehydration. These abilities are linked to a recently discovered damage suppressor protein (Dsup). Dsup is a nucleosome-binding protein that avoids DNA damage after X-ray and oxidative stress exposure without impairing cell life in Dsup-transfected animal and plant cells. The exact “protective” role of this protein is still under study. In human cells, we confirmed that Dsup confers resistance to UV-C and H₂O₂ exposure compared to untransfected cells. A different transcription factor activation was also observed. In addition, a different expression of endogenous genes involved in apoptosis, cell survival and DNA repair was found in Dsup+ cells after H₂O₂ and UV-C. In UV-C exposed cells, Dsup efficiently upregulates DNA damage repair genes, while H₂O₂ treatment only marginally involves the activation of pathways responsible for DNA repair in Dsup+ cells. These data are in agreement with the idea of a direct protective effect of the protein on DNA after oxidative stress. In conclusion, our data may help to outline the different mechanisms by which the Dsup protein works in response to different insults.