Reactive Oxygen Species Signaling Research Articles

Balanced regulation of ROS production and inflammasome activation in preventing early development of colorectal cancer.

Reactive oxygen species (ROS) production and inflammasome activation are the key components of the innate immune response to microbial infection and sterile insults. ROS are at the intersection of inflammation and immunity during cancer development. Balanced regulation of ROS production and inflammasome activation serves as the central hub of innate immunity, determining whether a cell will survive or undergo cell death. However, the mechanisms underlying this balanced regulation remain unclear. Mitochondria and NADPH oxidases are the two major sources of ROS production. Recently, NCF4, a component of the NADPH oxidase complex that primarily contributes to ROS generation in phagocytes, was reported to balance ROS production and inflammasome activation in macrophages. The phosphorylation and puncta distribution of NCF4 shifts from the membrane-bound NADPH complex to the perinuclear region, promoting ASC speck formation and inflammasome activation, which triggers downstream IL-18-IFN-γ signaling to prevent the progression of colorectal cancer (CRC). Here, we review ROS signaling and inflammasome activation studies in colitis-associated CRC and propose that NCF4 acts as a ROS sensor that balances ROS production and inflammasome activation. In addition, NCF4 is a susceptibility gene for Crohn's disease (CD) and CRC. We discuss the evidence demonstrating NCF4's crucial role in facilitating cell-cell contact between immune cells and intestinal cells, and mediating the paracrine effects of inflammatory cytokines and ROS. This coordination of the signaling network helps create a robust immune microenvironment that effectively prevents epithelial cell mutagenesis and tumorigenesis during the early stage of colitis-associated CRC.

Genome-wide identification and biochemical characterization of glycoside hydrolase gene family members in Tilletia Horrida.

Rice kernel smut, caused by Tilletia horrida, is becoming an increasingly serious disease in hybrid rice planting, leading to production losses and quality decline of male-sterile rice varieties. Successful infection requires an efficient energy source that the pathogen obtains from rice plants, such as carbohydrates. Glycoside hydrolases (GHs), one of the largest sub-families in the cell wall-degrading enzyme family, play a key role in the infection progress of pathogens. To investigate their roles in facilitating infection, in this study, we identified and characterized genes encoding GH family proteins of T. horrida and further explored the functions and structures of these genes. Through genome-wide sequencing and bioinformatics analyses, 52 GH genes were identified from T. horrida, named ThGhd_1 to ThGhd_52. The subcellular location, conserved motifs, and structures of ThGhds were identified by bioinformatics analyses. Phylogenetic analysis revealed that ThGhds with similar domains clustered together, although some proteins clustered in different branches, which might reflect functional diversity. Protein-protein interaction network analysis revealed that ThGhds interact with partner proteins involved in reactive oxygen species signaling, protein kinase activity, and plant hormone signal transduction pathways. RNA-sequencing analysis showed that the expression of ThGhd genes responded differently at different infection time points, with dynamic changes detected during the T. horrida infection process, indicating that these genes are involved in interactions with rice and have potential roles in pathogenic mechanisms. The results of this study provide valuable resources for the structure elucidation of GH family proteins of T. horrida and can help to further elucidate their roles in pathogenesis.

The regulatory network and critical factors promoting programmed cell death during embryogenesis.

Programmed cell death (PCD) is essential for animal and plant development. However, the knowledge of the mechanism regulating PCD in plants remains limited, largely due to technical limitations. Previously, we determined that the protease NtCP14 could trigger PCD in the embryonic suspensor of tobacco (Nicotiana tabacum), providing a unique opportunity to overcome the limitations by creating synchronous two-celled proembryos with ongoing PCD for transcriptome analysis and regulatory factor screening. Here, we performed comparative transcriptome analysis using isolated two-celled proembryos and explored the potential regulatory network underlying NtCP14-triggered PCD. Multiple phytohormones, calcium, microtubule organization, the immunity system, soluble N-ethylmaleimide-sensitive factor attachment protein receptor proteins, long non-coding RNAs and alternative splicing are addressed as critical factors involved in the early stage of suspensor PCD. Genes thought to play crucial roles in suspensor PCD are highlighted. Notably, decreased antioxidant gene expression and increased reactive oxygen species (ROS) levels during suspensor PCD suggest a critical role for ROS signaling in the initiation of NtCP14-triggered PCD. Furthermore, five genes in the regulatory network are recommended as immediate downstream elements of NtCP14. Together, our analysis outlines an overall molecular network underlying protease-triggered PCD and provides a reliable database and valuable clues for targeting elements immediately downstream of NtCP14 to overcome technical bottlenecks and gain deep insight into the molecular mechanism regulating plant PCD.

Hypoxia-Induced Mitochondrial ROS and Function in Pulmonary Arterial Endothelial Cells.

Pulmonary artery endothelial cells (PAECs) are a major contributor to hypoxic pulmonary hypertension (PH) due to the possible roles of reactive oxygen species (ROS). However, the molecular mechanisms and functional roles of ROS in PAECs are not well established. In this study, we first used Amplex UltraRed reagent to assess hydrogen peroxide (H2O2) generation. The result indicated that hypoxic exposure resulted in a significant increase in Amplex UltraRed-derived fluorescence (i.e., H2O2 production) in human PAECs. To complement this result, we employed lucigenin as a probe to detect superoxide (O2-) production. Our assays showed that hypoxia largely increased O2- production. Hypoxia also enhanced H2O2 production in the mitochondria from PAECs. Using the genetically encoded H2O2 sensor HyPer, we further revealed the hypoxic ROS production in PAECs, which was fully blocked by the mitochondrial inhibitor rotenone or myxothiazol. Interestingly, hypoxia caused an increase in the migration of PAECs, determined by scratch wound assay. In contrast, nicotine, a major cigarette or e-cigarette component, had no effect. Moreover, hypoxia and nicotine co-exposure further increased migration. Transfection of lentiviral shRNAs specific for the mitochondrial Rieske iron-sulfur protein (RISP), which knocked down its expression and associated ROS generation, inhibited the hypoxic migration of PAECs. Hypoxia largely increased the proliferation of PAECs, determined using Ki67 staining and direct cell number accounting. Similarly, nicotine caused a large increase in proliferation. Moreover, hypoxia/nicotine co-exposure elicited a further increase in cell proliferation. RISP knockdown inhibited the proliferation of PAECs following hypoxia, nicotine exposure, and hypoxia/nicotine co-exposure. Taken together, our data demonstrate that hypoxia increases RISP-mediated mitochondrial ROS production, migration, and proliferation in human PAECs; nicotine has no effect on migration, increases proliferation, and promotes hypoxic proliferation; the effects of nicotine are largely mediated by RISP-dependent mitochondrial ROS signaling. Conceivably, PAECs may contribute to PH via the RISP-mediated mitochondrial ROS.

Microenvironment Self-Adaptive Nanomedicine Promotes Spinal Cord Repair by Suppressing Inflammation Cascade and Neural Apoptosis.

Despite various biomaterial-based strategies are tried in spinal cord injury (SCI), developing safe and effective microinvasive pharmacotherapy strategies is still an unmet clinical need. Stimuli-responsive nanomedicine has emerged as a promising non-invasion technology, which enhances drug delivery and promotes functional recovery following SCI. Considering the multiple progressive pathological events and the blood spinal cord barrier (BSCB) associating SCI, a microenvironment self-adaptive nanoparticle (custom-designed with rabies virus glycoprotein 29-RVG29 and hyaluronic acid-HA, RHNP) capable of consistently crossing the BSCB and selectively targeting inflammatory cells and neural cells based on different stages of SCI are developed. The data indicated that RHNP can effectively traverse the BSCB through RVG29, and adaptively modulate cellular internalization by selectively exposing either HA or RVG29 through diselenide bonds, depending on pathological reactive oxygen species (ROS) signals. Furthermore, curcumin is loaded into RHNP (RHNP-Cur) to improve motor function and coordination of hind-limbs in a traumatic SCI mouse model. This study finds that RHNP-Cur exhibited inhibitory effects on the inflammatory cascade originating from M1 microglia/macrophages and neurotoxic astrocytes, and protected neural cells from inflammation-induced apoptosis during nerve regeneration. Collectively, the work provides a microenvironment self-adaptive nanomedicine which enables efficient microinvasive treatment of SCI.

The Switching of the Type of a ROS Signal from Mitochondria: The Role of Respiratory Substrates and Permeability Transition

Flashes of superoxide anion (O2−) in mitochondria are generated spontaneously or during the opening of the permeability transition pore (mPTP) and a sudden change in the metabolic state of a cell. Under certain conditions, O2− can leave the mitochondrial matrix and perform signaling functions beyond mitochondria. In this work, we studied the kinetics of the release of O2− and H2O2 from isolated mitochondria upon mPTP opening and the modulation of the metabolic state of mitochondria by the substrates of respiration and oxidative phosphorylation. It was found that mPTP opening leads to suppression of H2O2 emission and activation of the O2− burst. When the induction of mPTP was blocked by its antagonists (cyclosporine A, ruthenium red, EGTA), the level of substrates of respiration and oxidative phosphorylation and the selective inhibitors of complexes I and V determined the type of reactive oxygen species (ROS) emitted by mitochondria. It was concluded that upon complete and partial reduction and complete oxidation of redox centers of the respiratory chain, mitochondria emit H2O2, O2−, and nothing, respectively. The results indicate that the mPTP- and substrate-dependent switching of the type of ROS leaving mitochondria may be the basis for O2−- and H2O2-selective redox signaling in a cell.

NRF3-mediated mitochondrial superoxide promotes cardiomyocyte apoptosis and impairs cardiac functions by suppressing Pitx2

Abstract Background Myocardial infarction (MI) elicits mitochondria reactive oxygen species (ROS) production and cardiomyocyte apoptosis. Nrf3 (Nuclear factor erythroid 2-related factor 3) has an established role in regulating redox signaling and tissue homeostasis. Herein, we aimed to uncover the exact role and potential mechanism of Nrf3 in injury-induced cardiac remodeling. Methods Global (Nrf3-KO) and cardiomyocyte-specific (NRF3△CM) Nrf3 knockout mice were subjected to MI or ischemia/reperfusion (I/R) injury, followed by functional and histopathological analysis. Primary neonatal mice (NMVMs) and rat (NRVMs) ventricular myocytes as well as cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) were used to detect the possible impact of Nrf3 on cardiomyocyte apoptosis and mitochondrial ROS production. Chromatin immunoprecipitation sequencing and immunoprecipitation–mass spectrometry analysis were used to uncover potential targets of Nrf3. MitoPQ administration and cardiomyocyte-specific AAV vector were used to further confirm the in vivo relevance of the identified signal pathways. Results Increased level of Nrf3 was observed in cardiomyocytes within border zone of infarcted human heart and murine cardiac tissues post-MI. Both global and cardiomyocyte-specific Nrf3 knockout significantly decreased injury-induced mitochondrial ROS production and cardiomyocyte apoptosis, consequently improving cardiac functions. Additionally, cardiac-specific Nrf3 overexpression reversed the cardiac phenotypes observed in Nrf3-KO mice. Functional studies showed that Nrf3 promoted NMVM, NRVM and hiPSC-CM apoptosis by increasing mitochondrial ROS production. Critically, restoring mitochondrial ROS using MitoParaquat blunted the beneficial effects of Nrf3 deletion on cardiac functions and remodeling. Mechanistically, the cardiac redox regulator paired-like homeodomain transcription factor 2 (Pitx2) was identified as one of the main target genes of Nrf3. Specifically, Nrf3 binds to Pitx2 gene promoter where it increases Pitx2 gene promoter DNA methylation through recruiting heterogeneous nuclear ribonucleoprotein K and DNA-methyltransferase 1 complex, thereby inhibiting Pitx2 expression. Importantly, cardiomyocyte-specific knockdown of Pitx2 blunted the beneficial effects of Nrf3 deletion on cardiac functions and remodeling. Conclusions Nrf3 promotes injury-induced cardiomyocyte apoptosis and deteriorates cardiac functions by increasing mitochondrial ROS production via suppressing Pitx2 expression. Targeting Nrf3-Pitx2-mitochondrial ROS signal axis could represent novel therapeutics for treating MI patients.Graphic Abstract

Metformin suppresses metabolic dysfunction-associated fatty liver disease by ferroptosis and apoptosis via activation of oxidative stress

Metformin is known for its antioxidant properties and ability to ameliorate metabolic dysfunction-associated fatty liver disease (MAFLD) and is the focus of this study. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is linked to MAFLD risk. This study investigated the effects of metformin on ferroptosis in free fatty acid (FFA)-treated Huh7 hepatoma cells and its association with MAFLD risk. Using Western blot, immunofluorescence, and ELISA, this study revealed that FFA treatment led to increased intracellular fat and iron accumulation, heightened Lp-PLA2 expression, reduced levels of the cysteine transporter SLC7A11 and glutathione peroxidase 4 (GPX4), altered glutathione (GSH)/oxidized glutathione (GSSG) ratios, generation of reactive oxygen species (ROS), and initiation of lipid peroxidation, which ultimately resulted in cell ferroptosis. Importantly, metformin reversed FFA-induced iron accumulation, and this effect was attenuated by ferrostatin-1 but enhanced by erastin, RSL3, and si-GPX4. Additionally, metformin activated antioxidant and antiapoptotic mechanisms, which reduced lipid peroxidation and suppressed Lp-PLA2 expression in FFA-treated Huh7 cells. In conclusion, our findings indicate that metformin may protect against MAFLD by inhibiting iron accumulation and Lp-PLA2 expression through the ROS, ferroptosis, and apoptosis signaling pathways. This study highlights potential therapeutic strategies for managing MAFLD-related risks and emphasizes the diverse roles of metformin in maintaining hepatocyte balance.

Environmental salinity differentiates responses to acute hypothermal stress in milkfish

Global warming has led to an increase in the frequency of cold extremes, causing significant economic losses in aquaculture, particularly in subtropical regions. Milkfish (Chanos chanos) holds significant importance in aquaculture within subtropical Asian regions. Despite milkfish's ability to tolerate varying salinity levels, frequent cold snaps associated with extreme weather events have caused substantial mortality. Understanding the molecular and cellular mechanisms underlying cold stress-induced cell death is crucial for developing effective strategies to mitigate such losses. Given the pivotal role of the liver in fish physiology, we established a primary milkfish hepatocyte culture demonstrating robust proliferation and expressing a unique marker leptin A. The molecular characterization of cold-treated hepatocytes at 18 °C showed that the mRNA levels of superoxide dismutase (sod1) and catalase (cat), responsible for neutralizing reactive oxygen species (ROS), were downregulated in freshwater (FW) conditions, while cat expression was upregulated in seawater (SW) conditions. This differential modulation of ROS signaling implies distinct responses in FW and SW, leading to higher ROS levels and increased cell death in FW condition compared to those in SW. Transcriptomic analysis of liver tissues from milkfish reared in FW or SW, with or without cold stress, revealed distinct gene expression patterns. Although cold stress affected a common set of genes in both FW and SW conditions, SW-specific cold responsive genes are associated with metabolic pathways while FW-specific genes were linked to cell proliferation pathways. Notably, gene set enrichment analysis highlighted the downregulation of cytochrome-related genes, a major source of ROS production, in response to cold stress in SW. In summary, our study unveils an insightful mechanism whereby the salinity of SW counteracts cold stress-induced ROS signaling, emphasizing the feasibility and practicality of preconditioning fish in SW as a preventive measure against cold stress-induced mortality.

Formation of multinucleated osteoclasts depends on an oxidized species of cell surface-associated La protein.

The bone-resorbing activity of osteoclasts plays a critical role in the life-long remodeling of our bones that is perturbed in many bone loss diseases. Multinucleated osteoclasts are formed by the fusion of precursor cells, and larger cells - generated by an increased number of cell fusion events - have higher resorptive activity. We find that osteoclast fusion and bone resorption are promoted by reactive oxygen species (ROS) signaling and by an unconventional low molecular weight species of La protein, located at the osteoclast surface. Here, we develop the hypothesis that La's unique regulatory role in osteoclast multinucleation and function is controlled by an ROS switch in La trafficking. Using antibodies that recognize reduced or oxidized species of La, we find that differentiating osteoclasts enrich an oxidized species of La at the cell surface, which is distinct from the reduced La species conventionally localized within cell nuclei. ROS signaling triggers the shift from reduced to oxidized La species, its dephosphorylation and delivery to the surface of osteoclasts, where La promotes multinucleation and resorptive activity. Moreover, intracellular ROS signaling in differentiating osteoclasts oxidizes critical cysteine residues in the C-terminal half of La, producing this unconventional La species that promotes osteoclast fusion. Our findings suggest that redox signaling induces changes in the location and function of La and may represent a promising target for novel skeletal therapies.

Formation of multinucleated osteoclasts depends on an oxidized species of cell surface-associated La protein

The bone-resorbing activity of osteoclasts plays a critical role in the life-long remodeling of our bones that is perturbed in many bone loss diseases. Multinucleated osteoclasts are formed by the fusion of precursor cells, and larger cells – generated by an increased number of cell fusion events – have higher resorptive activity. We find that osteoclast fusion and bone resorption are promoted by reactive oxygen species (ROS) signaling and by an unconventional low molecular weight species of La protein, located at the osteoclast surface. Here, we develop the hypothesis that La’s unique regulatory role in osteoclast multinucleation and function is controlled by an ROS switch in La trafficking. Using antibodies that recognize reduced or oxidized species of La, we find that differentiating osteoclasts enrich an oxidized species of La at the cell surface, which is distinct from the reduced La species conventionally localized within cell nuclei. ROS signaling triggers the shift from reduced to oxidized La species, its dephosphorylation and delivery to the surface of osteoclasts, where La promotes multinucleation and resorptive activity. Moreover, intracellular ROS signaling in differentiating osteoclasts oxidizes critical cysteine residues in the C-terminal half of La, producing this unconventional La species that promotes osteoclast fusion. Our findings suggest that redox signaling induces changes in the location and function of La and may represent a promising target for novel skeletal therapies.

Unveiling the molecular symphony: microRNA160a-Auxin Response Factor 18 module orchestrates low potassium tolerance in banana (Musa acuminata L.)

Potassium (K) is an essential nutrient for the growth and development of most plants. In banana (Musa acuminata L.), microRNA160a (miR160a) is suggested to potentially contribute to the response to low K+ stress by modulating the auxin signaling pathway. However, further investigation is required to elucidate its specific regulatory mechanism. This study presents evidence highlighting the critical role of the miR160a-Auxin Response Factor 18 (ARF18) module in conferring low K+ tolerance in banana. Both miR160a and its predicted target gene ARF18 displayed elevated expression levels in banana roots, with their expression profiles significantly altered under low K+ stress. The inhibitory effect of mac-miR160a on the expression of MaARF18-like-2 was confirmed through tobacco transient transformation and dual-Luciferase reporter assay. Surprisingly, Arabidopsis lines overexpressing mac-miR160a (mac-miR160a OE) exhibited enhanced tolerance to low K+ stress. Conversely, Arabidopsis lines overexpressing MaARF18-like-2 (MaARF18-like-2 OE) displayed increased sensitivity to K+ deficiency. Additionally, RNA sequencing (RNA-seq) analysis revealed that MaARF18-like-2 mediates the response of Arabidopsis to low K+ stress by influencing the expression of genes associated with Ca2+, ion transport, and reactive oxygen species (ROS) signaling. In conclusion, our study provides novel insights into the molecular mechanism of the miR160a-ARF18-like-2 module in the plant response to low K+ stress.

Regulation of Reactive Oxygen Species on Platelet Activation and Apoptosis

To investigate how reactive oxygen species (ROS) regulates the signal transduction of platelet activation and apoptosis, and to explore the relationship between platelet activation and apoptosis. Platelets were directly stimulated with thrombin or pretreated with ROS inhibitor N-acetylcysteine (NAC) before being stimulated with thrombin, and then flow cytometry was used to detect the effects of thrombin and NAC on P-selectin expression, αⅡbβ3 activation, mitochondrial membrane potential depolarization, phosphatidylserine (PS) externalization, ROS expression and platelet aggregation. Thrombin could induce the production of ROS in platelets in a concentration- and time-dependent manner. 0.01 U thrombin induced ROS-dependent high degree of integrin αⅡbβ3 activation, P-selectin expression, and platelet aggregation. The platelets induced by different concentration gradients of thrombin exhibited ROS-dependent mitochondrial membrane potential depolarization and PS externalization in platelets. After induction with thrombin for 30 min, the activation of integrin αⅡbβ3 in platelets reached its maximum level, and after 60 minutes, the depolarization of mitochondrial membrane potential in platelets reached its maximum level. However, the expression of P-selectin, depolarization of mitochondrial membrane potential, and platelet aggregation function were all inhibited to a certain extent when the platelets were pretreated with ROS inhibitor NAC and then induced with thrombin. When platelets are induced by thrombin, ROS first regulates the activation of platelets, and then regulates the apoptosis of platelets. Both platelet activation and apoptosis depend on the production of ROS in platelets, and the signals of activation and apoptosis occur orderly. Inhibiting the ROS signal in platelets can effectively inhibit the activation and apoptosis of platelets.

Endothelial Reactive Oxygen Species: Key Players in Cardiovascular Health and Disease.

Significance: Endothelial cells (ECs) line the entire vasculature system and serve as both barriers and facilitators of intra- and interorgan communication. Positioned to rapidly sense internal and external stressors, ECs dynamically adjust their functionality. Endothelial dysfunction occurs when the ability of ECs to react to stressors is impaired, which precedes many cardiovascular diseases (CVDs). While EC reactive oxygen species (ROS) have historically been implicated as mediators of endothelial dysfunction, more recent studies highlight the central role of ROS in physiological endothelial signaling. Recent Advances: New evidence has uncovered that EC ROS are fundamental in determining how ECs interact with their environment and respond to stress. EC ROS levels are mediated by external factors such as diet and pathogens, as well as inherent characteristics, including sex and location. Changes in EC ROS impact EC function, leading to changes in metabolism, cell communication, and potentially disrupted signaling in CVDs. Critical Issues: Current endothelial biology concepts integrate the dual nature of ROS, emphasizing the importance of EC ROS in physiological stress adaptation and their contribution to CVDs. Understanding the discrete, localized signaling of EC ROS will be critical in preventing adverse cardiovascular outcomes. Future Directions: Exploring how the EC ROS environment alters EC function and cross-cellular communication is critical. Considering the inherent heterogeneity among EC populations and understanding how EC ROS contribute to this diversity and the role of sexual dimorphism in the EC ROS environment will be fundamental for developing new effective cardiovascular treatment strategies.

GUARD CELL HYDROGEN PEROXIDE-RESISTANT1 functions upstream of reactive carbonyl species production in Arabidopsis guard-cell abscisic acid signaling.

GUARD CELL HYDROGEN PEROXIDE-RESISTANT1 (GHR1), a leucine-rich repeat receptor-like kinase, is involved in abscisic acid (ABA)-induced stomatal closure. We investigated the role of GHR1 in reactive oxygen species (ROS) signaling for ABA-induced stomatal closure. Abscisic acid induced ROS production in wild type (WT) and the ghr1 of Arabidopsis thaliana. Hydrogen peroxide induced stomatal closure, accompanying the generation of acrolein in guard cells. The reactive carbonyl species (RCS) scavengers inhibited the ABA- and H2O2-induced stomatal closure in WT. In the ghr1, H2O2 failed to induce acrolein production and stomatal closure while RCS induced stomatal closure. Thus, GHR1 functions downstream of ROS and is required for the generation of RCS in guard-cell ABA signaling. In the ghr1, Ca2+ induced stomatal closure but RCS did not activate ICa channels. The GHR1 may be also involved in a Ca2+-independent pathway for ABA-induced stomatal closure.

Hepatotoxic assessment in a microphysiological system: Simulation of the drug absorption and toxic process after an overdosed acetaminophen on intestinal-liver-on-chip

To compensate the limitation of animal models, new models were proposed for drug safety evaluation to refine and reduce existing models. To mimic drug absorption and metabolism and predict toxicokinetic and toxic effects in an in vitro intestinal-liver microphysiological system (MPS), we constructed an intestinal-liver-on-chip and detected the acute liver injury process after an overdose of acetaminophen (APAP). Caco-2 and HT29-MTX-E12 cell lines were utilized to establish intestinal equivalents, along with HepG2, HUVEC-T1, and THP-1 induced by PMA and human hepatic stellate cell to establish liver equivalents. The APAP concentration was determined using high-performance liquid chromatography, and the toxicokinetic parameters were fitted using the non-compartmental analysis method by Phoenix. Changes in liver injury biomarkers aspartate aminotransferase and alanine aminotransferase, and liver function marker albumin indicated that the short-term culture of the two organs-on-chip model was stable for 4 days. Reactive oxygen species signaling was enhanced after APAP administration, along with decreased mitochondrial membrane potential, activated caspase-3, and enhanced p53 signaling, indicating a toxic response induced by APAP overdose. In the gut-liver MPS model, we fitted the toxicokinetic parameters and simulated the hepatotoxicity procedure following an APAP overdose, which will facilitate the organ-on-chips application in drug toxicity assays.

Photosynthetic ROS and retrograde signaling pathways.

Sessile plants harness mitochondria and chloroplasts to sense and adapt to diverse environmental stimuli. These complex processes involve the generation of pivotal signaling molecules, including reactive oxygen species (ROS), phytohormones, volatiles, and diverse metabolites. Furthermore, the specific modulation of chloroplast proteins, through activation or deactivation, significantly enhances the plant's capacity to engage with its dynamic surroundings. While existing reviews have extensively covered the role of plastidial retrograde modules in developmental and light signaling, our focus lies in investigating how chloroplasts leverage photosynthetic ROS to navigate environmental fluctuations and counteract oxidative stress, thereby sustaining primary metabolism. Unraveling the nuanced interplay between photosynthetic ROS and plant stress responses holds promise for uncovering new insights that could reinforce stress resistance and optimize net photosynthesis rates. This exploration aspires to pave the way for innovative strategies to enhance plant resilience and agricultural productivity amidst changing environmental conditions.

Antioxidant enzyme Prdx1 inhibits osteoclastogenesis via suppressing ROS and NFATc1 signaling pathways.

Bone is a dynamic organ which continuously undergoes remodeling throughout one's lifetime. Cellular production of reactive oxygen species (ROS) is essential for regulating bone homeostasis. Osteoclasts, multinucleated giant cells differentiated from macrophage lineage, are responsible for osteolytic bone conditions which are closely linked to ROS signaling pathways. In this study, an anti-ROS enzyme, peroxiredoxin 1 (Prdx1) was found to be expressed both in bone marrow macrophages and osteoclasts. Recombinant Prdx1 protein was found to dose-dependently inhibit ROS production and osteoclast differentiation. Mechanistically, Prdx1 protein also attenuated NFATc1 activation as well as the expression of C-Fos, V-ATPase-d2, Cathepsin K, and Integrin αV. Collectively, Prdx1 is a negative regulator on osteoclast formation via inhibiting RANKL-mediated ROS activity, thus suggesting its potential application for treating osteoclast related disorders.

Damage-induced basal epithelial cell migration modulates the spatial organization of redox signaling and sensory neuron regeneration.

Epithelial damage leads to early reactive oxygen species (ROS) signaling, which regulates sensory neuron regeneration and tissue repair. How the initial type of tissue injury influences early damage signaling and regenerative growth of sensory axons remains unclear. Previously we reported that thermal injury triggers distinct early tissue responses in larval zebrafish. Here, we found that thermal but not mechanical injury impairs sensory axon regeneration and function. Real-time imaging revealed an immediate tissue response to thermal injury characterized by the rapid Arp2/3-dependent migration of keratinocytes, which was associated with tissue scale ROS production and sustained sensory axon damage. Isotonic treatment was sufficient to limit keratinocyte movement, spatially restrict ROS production, and rescue sensory neuron function. These results suggest that early keratinocyte dynamics regulate the spatial and temporal pattern of long-term signaling in the wound microenvironment during tissue repair.

ARMCX3 regulates ROS signaling, affects neural differentiation and inflammatory microenvironment in dental pulp stem cells

BackgroundThe neural differentiation of dental pulp stem cells (DPSCs) exhibits great potential in the treatment of dental pulp repair and neurodegenerative diseases. However, the precise molecular mechanisms underlying this process remain unclear. This study was designed to reveal the roles and regulatory mechanisms of the armadillo repeat-containing X-linked 3 (ARMCX3) in neural differentiation and inflammatory microenvironment in human DPSCs (hDPSCs). MethodsWe treated hDPSCs with porphyromonas gingivalis lipopolysaccharide (Pg-LPS) to simulate the inflammatory microenvironment. Then the lentiviral vectors were introduced to construct stable cell lines with ARMCX3 knockdown or overexpression. The expression of neural-specific markers, ARMCX3 and inflammation factors were estimated by immunofluorescence (IF), quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) assays. Additionally, we used IF assays and specific kits to investigate the regulatory role of ARMCX3 on reactive oxygen species (ROS) signaling. Moreover, a ROS inhibitor was utilized to verify whether ROS inhibition reversed the effects of ARMCX3 in Pg-LPS-treated hDPSCs. ResultsThis work illustrated that Pg-LPS treatment significantly enhanced ARMCX3 expression and inflammatory response, and inhibited neural differentiation in hDPSCs. ARMCX3 knockdown effectively accelerated neural differentiation and controlled inflammatory cytokines at a lower level in hDPSCs in the presence of Pg-LPS. Additionally, knockdown of ARMCX3 notably reduced ROS production and ROS inhibition effectively eliminated the roles of ARMCX3 overexpression in hDPSCs. Besides, all results were proved to be statistically significant. ConclusionThis investigation proved that ARMCX3 affected neural differentiation and inflammation microenvironment in hDPSCs at least partly by mediating ROS signal. These findings provided a new perspective on the mechanism of neural differentiation of hDPSCs and help to better explore the therapeutic schedule of pulpitis and neurodegenerative diseases.