Reactive Oxygen Species Scavenger Research Articles

Mesoporous Polydopamine Nanotherapeutics for MRI-Guided Cancer Photothermal and Anti-Inflammatory Therapy.

As a burgeoning cancer treatment modality, photothermal therapy (PTT) has shown robust anti-tumor effects. However, it still faces numerous challenges, such as triggering an inflammatory response and potentially increasing the risk of cancer recurrence. To address these concerns, integration of PTT with anti-inflammatory therapies presents a promising approach to enhance the efficacy of cancer treatment and meanwhile reduce the risk of recurrence. In this study, Gd3+ was first chelated with dopamine to create Gd-DA chelates, and then the mesoporous dopamine nanoparticles MX@Arg-Gd-MPDA (MAGM NPs) were synthesized by combining arginine (Arg) and the anti-inflammatory medication meloxicam (MX). The photothermal properties of MAGM NPs were then defined and examined; the in vivo MRI imaging effect, as well as MAGM NPs' anti-cancer and anti-inflammatory efficiency, were tested in a mouse model of breast cancer. The incorporation of Arg doping into MAGM NPs was intended to boost its photothermal conversion efficiency and reactive oxygen species (ROS) scavenging ability. Additionally, synergizing with the anti-inflammatory agent meloxicam (MX) within the nanoparticles aimed to enhance the anti-inflammatory effect following photothermal therapy. Furthermore, gadolinium ions (Gd3+) were chelated into the nanostructure to enable precise T1-T2 dual-mode magnetic resonance imaging (MRI) of the intratumor accumulation profile. This imaging capability was leveraged to guide the implementation of photothermal therapy. Animal experiments demonstrated that MAGM NPs exerted a notable anticancer effect in a 4T1 breast cancer mouse model, under the precise guidance of MRI.

Tripartite interactions between grapevine, viruses, and arbuscular mycorrhizal fungi provide insights into modulation of oxidative stress responses

Arbuscular mycorrhizal fungi (AMF) can be beneficial for plants exposed to abiotic and biotic stressors. Although widely present in agroecosystems, AMF influence on crop responses to virus infection is underexplored, particularly in woody plant species such as grapevine. Here, a two-year greenhouse experiment was set up to test the hypothesis that AMF alleviate virus-induced oxidative stress in grapevine. The ‘Merlot’ cultivar was infected with three grapevine-associated viruses and subsequently colonized with two AMF inocula, containing one or three species, respectively. Five and fifteen months after AMF inoculation, lipid peroxidation - LPO as an indicator of oxidative stress and indicators of antioxidative response (proline, ascorbate - AsA, superoxide dismutase - SOD, ascorbate- APX and guaiacol peroxidases - GPOD, polyphenol oxidase - PPO, glutathione reductase - GR) were analysed. Expression of genes coding for a stilbene synthase (STS1), an enhanced disease susceptibility (EDS1) and a lipoxygenase (LOX) were determined in the second harvesting. AMF induced reduction of AsA and SOD over both years, which, combined with not AMF-triggered APX and GR, suggests decreased activation of the ascorbate-glutathione cycle. In the mature phase of the AM symbiosis establishment GPOD emerged as an important mechanism for scavenging H2O2 accumulation. These results, together with reduction in STS1 and increase in EDS1 gene expression, suggest more efficient reactive oxygen species scavenging in plants inoculated with AMF. Composition of AMF inocula was important for proline accumulation. Overall, our study improves the knowledge on ubiquitous grapevine-virus-AMF systems in the field, highlighting that established functional AM symbiosis could reduce virus-induced stress.

Gastrointestinal Self-Adaptive and Nutrient Self-Sufficient Akkermansia muciniphila-Gelatin Porous Microgels for Synergistic Therapy of Ulcerative Colitis.

To realize effective and long-term synergistic therapy of ulcerative colitis (UC) with probiotics, we developed gastrointestinal self-adaptive and nutrient self-sufficient Akkermansia muciniphila (AKK)-gelatin porous microgels (AKK@GPMGs). In AKK@GPMGs, AKK was covered with sequential layers of proanthocyanidins (PAs), mucin (MUC), and phosphatidylcholine (PC) to obtain AKK@PAs-MUC-PC (AKK@PMP), and then encapsulated within the methacrylate-modified gelatin porous microgels. AKK@GPMGs provide sufficient mucus as a nutrition source for AKK and boost resistance to stomach acid by 30.49-fold, and colonization in the intestines is enhanced by 83.46 times. The microgels can be dissociated by matrix metalloproteinase at the inflammatory sites of the intestine, and release AKK@PMP, which acts as "band-aid" that adheres to the inflamed colon for a long time and offers improved synergistic therapy for UC. Compared to uncoated AKK, AKK@GPMGs increase reactive oxygen species scavenging capacity by 26.47 times, improve the intestinal mucus layer thickness by 5.63 times, increase the goblet cells abundance by 3.93 times, reduce intestinal permeability by 5.60 times and significantly enhance beneficial gut microbiota while repressing harmful microbiota. These results indicate that AKK@GPMGs can restore mucus layer and tight junction integrity, reduce inflammation and oxidative stress, and regulate gut microbiota homeostasis to effectively treat intestinal inflammation.

Targeting the Main Sources of Reactive Oxygen Species Production: Possible Therapeutic Implications in Chronic Pain.

Humans have long been combating chronic pain. In clinical practice, opioids are firstchoice analgesics, but long-term use of these drugs can lead to serious adverse reactions. Finding new, safe and effective pain relievers that are useful treatments for chronic pain is an urgent medical need. Based on accumulating evidence from numerous studies, excess reactive oxygen species (ROS) contribute to the development and maintenance of chronic pain. Some antioxidants are potentially beneficial analgesics in the clinic, but ROS-dependent pathways are completely inhibited only by scavenging ROS directly targeting cellular or subcellular sites. Unfortunately, current antioxidant treatments do not achieve this effect. Furthermore, some antioxidants interfere with physiological redox signaling pathways and fail to reverse oxidative damage. Therefore, the key upstream processes and mechanisms of ROS production that lead to chronic pain in vivo must be identified to discover potential therapeutic targets related to the pathways that control ROS production in vivo. In this review, we summarize the sites and pathways involved in analgesia based on the three main mechanisms by which ROS are generated in vivo, discuss the preclinical evidence for the therapeutic potential of targeting these pathways in chronic pain, note the shortcomings of current research and highlight possible future research directions to provide new targets and evidence for the development of clinical analgesics.

Drug-Loaded Mesoporous Polydopamine Nanoparticles in Chitosan Hydrogels Enable Myocardial Infarction Repair through ROS Scavenging and Inhibition of Apoptosis.

In this study, we synthesized mesoporous polydopamine nanoparticles (MPDA NPs) using an emulsion-induced interface assembly strategy and loaded epigallocatechin gallate (EGCG) into MPDA NPs via electrostatic attraction to form EGCG@MPDA NPs. In the post myocardial infarction (MI) environment, these interventions specifically aimed to eliminate reactive oxygen species (ROS) and facilitate the repair of MI. We further combined them with a thermosensitive chitosan (CS) hydrogel to construct an injectable composite hydrogel (EGCG@MPDA/CS hydrogel). Utilizing in vitro experiments, the EGCG@MPDA/CS hydrogel exhibited excellent ROS-scavenging ability of H9C2 cells under the oxidative stress environment and also could inhibit their apoptosis. The EGCG@MPDA/CS hydrogel significantly promoted left ventricular ejection fraction (LVEF) in infarcted rat models post injection for 28 days compared to the PBS group (51.25 ± 1.73% vs 29.31 ± 0.78%, P < 0.05). In comparison to the PBS group, histological analysis revealed a substantial increase in left ventricular (LV) wall thickness in the EGCG@MPDA/CS hydrogel group (from 0.58 ± 0.03 to 1.39 ± 1.11 mm, P < 0.05). This work presents a novel approach to enhance MI repair by employing the EGCG@MPDA/CS hydrogel. This hydrogel effectively reduces local oxidative stress by ROS and stimulates the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway.

The homeostasis of ions and reactive oxygen species in root and shoot play crucial roles in the tolerance of alfalfa to salt alkali stress

High pH saline-alkali stress, mainly NaHCO3, limited the development of animal husbandry in Songnen Plain. Ion imbalance and reactive oxygen species (ROS) metabolism disorder caused by saline-alkali stress inhibited plant growth. In this study, we compared the differences in ion absorption, transport and ROS metabolism between saline-tolerant alfalfa (ZD) and saline-sensitive alfalfa (ZM) under NaHCO3 stress using physiology and transcripomics techniques. WGCNA analysis identified key genes associated with NaHCO3 stress-induced changes. NaHCO3 stress inhibited the absorption of K+ and Mg2+, but activated Ca2+ signal. Furthermore, ZD maintained higher K+, Mg2+ and Ca2+ contents and the K+/Na+ ratio than ZM, this is mainly related to the higher expression of proteins or channel-encoding genes involved in ion absorption and transport in ZD. Antioxidant enzyme systems can be activated in response to NaHCO3 stress. Peroxidase (EC 1.11.1.6), catalase (EC 1.11.1.7) and glutathione transferase (EC 2.5.1.18) activities were higher in ZD than ZM, and most genes encoding the relevant enzymes also demonstrated a stronger up-regulation trend in ZD. Although NaHCO3 stress inhibited Trx-Prx pathway, ZD related enzymes and their genes were also inhibited less than ZM. WGCNA results identified many genes involved in ion absorption, transport and antioxidant systems that play an important role in NaHCO3 stress adaptation. Collectively, ZD has the stronger ion homeostasis regulation and ROS scavenging ability, so it's more resistant to NaHCO3. The results provide theoretical guidance for further understanding of the molecular mechanism of NaHCO3 resistance and provide potential genes for research to improve saline-alkali tolerance in alfalfa.

2D MXene Nanosheets with ROS Scavenging Ability Effectively Delay Osteoarthritis Progression.

MXenes nanosheets with high conductivity, hydrophilicity, and excellent reactive oxygen species (ROS) scavenging ability have shown promise in treating various degenerative diseases correlated with abnormal ROS accumulation. Herein, the therapeutic potential of Ti3C2Tx nanosheets, which is the most widely investigated MXene material, in delaying osteoarthritis (OA) progression is demonstrated. In vitro experiments indicate the strong ROS scavenging capacity of Ti3C2Tx nanosheets and their acceptable biocompatibility. Ti3C2Tx nanosheets effectively protect chondrocytes from cell death induced by oxidative stress. In addition, Ti3C2Tx nanosheets demonstrate a prominent anti-inflammatory effect and the ability to restore homeostasis between anabolic activities and catabolic activities in chondrocytes. Furthermore, RNA sequencing reveals the potential mechanism underlying the Ti3C2Tx nanosheet-mediated therapeutic effect. Finally, the in vivo curative effect of Ti3C2Tx nanosheets is verified using a rat OA model. Histological staining and immunohistochemical analyses indicate that Ti3C2Tx nanosheets effectively ameliorate OA progression. Conclusively, the in vitro and in vivo experiments suggest that Ti3C2Tx nanosheets could be a promising and effective option for OA treatment.

Isovalerylspiramycin I suppresses small cell lung cancer proliferation via ATR/CHK1 mediated DNA damage response and PERK/eIF2α/ATF4/CHOP mediated ER stress

Small cell lung cancer (SCLC) urgently needs new therapeutic approaches. We found that the antibiotic-derived compound Isovalerylspiramycin I (ISP-I) has potent anti-tumor activity against SCLC cell lines H1048 and DMS53 both in vitro and in vivo. ISP-I induced apoptosis, G2/M phase cell cycle arrest, and mitochondrial respiratory chain dysfunction in both cell lines. Comprehensive RNA sequencing revealed that the anti-SCLC effects of ISP-I were primarily attributed to ATR/CHK1-mediated DNA damage response and PERK/eIF2α/ATF4/CHOP-mediated ER stress. Importantly, the induction of DNA damage, ER stress, and apoptosis by ISP-I was mitigated by the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC), underscoring the critical role of ROS in the anti-SCLC mechanism of ISP-I. Moreover, ISP-I treatment induced immunogenic cell death (ICD) in SCLC cells, as evidenced by increased adenosine triphosphate (ATP) secretion, elevated release of high-mobility group box 1 (HMGB1), and enhanced exposure of calreticulin (CRT) on the cell surface. Additionally, network pharmacology analysis, combined with cellular thermal shift assay (CETSA) and cycloheximide (CHX) chase experiments, demonstrated that ISP-I acted as a ligand for apurinic/apyrimidinic endonuclease 1 (APEX1) and promoted its degradation, leading to the accumulation of ROS. In conclusion, our findings elucidate the multifaceted mechanisms underlying the anti-cancer effects of ISP-I, highlighting its potential as a promising therapeutic candidate for SCLC treatment.

Ursolic acid, a natural endogenous compound, inhibits browning in fresh-cut apples

Enzymatic browning occurs rapidly in fresh-cut apples and can lead to economic losses. Although various methods have been developed to prevent this browning, physical methods are costly, and chemical methods are controversial, suggesting the potential usefulness of an endogenous natural browning inhibitor. In this study, the effects of ursolic acid (UA), a natural endogenous compound, on apple browning were investigated. It was found that UA inhibited the activity of polyphenol oxidase through Cu2+ chelation. Molecular docking indicated that the inhibition was reversible and mixed-type. Moreover, UA treatment promoted the scavenging of reactive oxygen species in fresh-cut apple and reduced the proliferation of microorganisms on the apple surface. Similar effects were observed on the browning of chestnut, eggplant, potatoes, and pears. In conclusion, the findings demonstrate the efficacy of UA on inhibiting browning in fresh-cut apple, together with an analysis of the mechanism involved.

Polydopamine-coated chondroitin sulfate methacryloyl multifunctional microspheres for wound treatment

The disappearance of the protective barrier after skin injury leads to the overproduction of reactive oxygen species (ROS) in response to various stimuli. Oxidative stress is one of the most important causes of delayed wound healing, leading to negative outcomes, such as excessive inflammatory response and impaired angiogenesis. In this study, we used microfluidic technology to integrate Prussian blue nanozymes and vascular endothelial growth factor and constructed multifunctional microspheres that improved local oxidative stress. In order to enhance the adhesion of the microspheres on the wound surface and prolong the release of the drug, we coated them with dopamine, ensuring uniform encapsulation on their surface. The microspheres adhered well to the wound surface and promoted wound healing by scavenging ROS, reducing the inflammatory response, and promoting angiogenesis. This strategy of integrating nanozymes and growth factors can have a synergistic effect, which is significant for wound healing.

Reactive oxygen species-inducing itraconazole and its anti-biofilm activity against resistant Candida parapsilosis sensu lato biofilm cells isolated from patients with recalcitrant onychomycosis.

Candida parapsilosis was introduced as the second most responsible for nail involvement. The colonization of biotic and abiotic surfaces by Candida spp.can result in the formation of biofilms, which possess a high level of resistance to typical antifungal agents. Since Candida spp. can produce biofilm mass on the surface of the nails, dermatologists should consider appropriate antifungals to eliminate both the planktonic and biofilm cells. The aim of this research was to determine the antifungal efficacy of itraconazole against C. parapsilosis sensu lato biofilm formations, in addition to its static effects. Ten C. parapsilosis sensu lato isolates were enrolled in this study. The use of itraconazole results in the accumulation of reactive oxygen species (ROS) during treatment. In order to verify the correlation between ROS and itraconazole-induced cell death, the viability of cells was analyzed by administering the ROS scavenger Ascorbic acid. The apoptotic features of itraconazole were analyzed using the Annexin V-FITC method. Based on current data, it was found that the generation of intracellular stresses by itraconazole is not observed in cells upon ROS inhibition, emphasizing the importance of intracellular ROS in the apoptotic mechanism of itraconazole. Targeting the oxidative defense system is a powerful point to use ROS-inducing antifungals as a superior choice for more effective therapies in case of recalcitrant onychomycosis.

Non-thermal atmospheric pressure plasma induces selective cancer cell apoptosis by modulating redox homeostasis

BackgroundAnticancer treatments aim to selectively target cancer cells without harming normal cells. While non-thermal atmospheric pressure plasma (NTAPP) has shown anticancer potential across various studies, the mechanisms behind its selective action on cancer cells remain inadequately understood. This study explores the mechanism of NTAPP-induced selective cell death and assesses its application in cancer therapy.MethodsWe treated HT1080 fibrosarcoma cells with NTAPP and assessed the intracellular levels of mitochondria-derived reactive oxygen species (ROS), mitochondrial function, and cell death mechanisms. We employed N-acetylcysteine to investigate ROS’s role in NTAPP-induced cell death. Additionally, single-cell RNA sequencing was used to compare gene expression in NTAPP-treated HT1080 cells and human normal fibroblasts (NF). Western blotting and immunofluorescence staining examined the expression and nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2), a key antioxidant gene transcription factor. We also evaluated autophagy activity through fluorescence staining and transmission electron microscopy.ResultsNTAPP treatment increased ROS levels and induced mitochondrial dysfunction, leading to apoptosis in HT1080 cells. The involvement of ROS in selective cancer cell death was confirmed by N-acetylcysteine treatment. Distinct gene expression patterns were observed between NTAPP-treated NF and HT1080 cells, with NF showing upregulated antioxidant gene expression. Notably, NRF2 expression and nuclear translocation increased in NF but not in HT1080 cells. Furthermore, autophagy activity was significantly higher in normal cells compared to cancer cells.ConclusionsOur study demonstrates that NTAPP induces selective cell death in fibrosarcoma cells through the downregulation of the NRF2-induced ROS scavenger system and inhibition of autophagy. These findings suggest NTAPP’s potential as a cancer therapy that minimizes damage to normal cells while effectively targeting cancer cells.

Morphological, physiological, and transcriptomic analyses indicate that cell wall properties and antioxidant processes are potential targets for improving the aluminium tolerance of broad beans

Aluminium (Al) stress is the second-leading abiotic stress on crops. An improved understanding of the response mechanisms of plants to Al stress will provide scientific guidance for enhancing the crops’ tolerance to Al stress. In this study, Al stress (50–200 μM AlCl3) caused visible damage to broad bean (Vicia faba L.) roots rather than shoots, which was attributed to Al accumulation and distribution in different tissues. Root transcriptomic analysis revealed that Al stress altered cell wall properties by downregulating lignin synthesis and several xyloglucan endotransglucosylase/hydrolase-, expansin- and peroxidase (POD)-encoding genes, which likely weakened cell extensibility to inhibit root growth. Additionally, Al stress impeded reactive oxygen species scavenging pathways involving POD activity and flavonoid biosynthesis, leading to oxidative damage characterised by malondialdehyde accumulation. These results indicate that optimising cell wall properties and/or enhancing antioxidant processes are crucial for alleviating Al toxicity to broad beans. Interestingly, exogenous application (500 and 1000 μM) of the flavonoid apigenin effectively alleviated Al toxicity in broad bean roots by partially improving the total antioxidant capacity of the roots. This study contributes to understanding the interaction between plants and Al and provides new strategies to alleviate Al toxicity in crops.

A glutathione S-transferase regulates lignin biosynthesis and enhances salt tolerance in tomato.

Salt stress adversely affects the growth and yield of crops. Glutathione S-transferases (GSTs) are involved in plant growth and responses to biotic and abiotic stresses. In this study, 400 mM NaCl stress significantly induced the expression of Glutathione S-transferase U43 (SlGSTU43) in the roots of the wild-type tomato (Solanum lycopersicum L.) plants. Overexpressing SlGSTU43 enhanced the ability of scavenging reactive oxygen species (ROS) in tomato leaves and roots under NaCl stress, while SlGSTU43 knock-out mutants showed the opposite performance. RNA sequencing analysis revealed that overexpressing SlGSTU43 affected the expression of genes related to lignin biosynthesis. We demonstrated that SlGSTU43 can regulate the lignin content in tomato through its interaction with SlCOMT2, a key enzyme involved in lignin biosynthesis, and promote the growth of tomato plants under NaCl stress. In addition, SlMYB71 and SlWRKY8 interact each other, and can directly bind to the promoter of SlGSTU43 to transcriptionally activate its expression separately or in combination. When SlMYB71 and SlWRKY8 were silenced in tomato plants individually or collectively, the plants were sensitive to NaCl stress, and their GST activities and lignin contents decreased. Our research indicates that SlGSTU43 can enhance salt stress tolerance in tomato by regulating lignin biosynthesis, which is regulated by interacting with SlCOMT2, as well as SlMYB71 and SlWRKY8. This finding broadens our understanding of GST functions.

UA influences the progression of breast cancer via the AhR/p27Kip1/cyclin E pathway.

Uric acid (UA) is the end product of purine metabolism. In recent years, UA has been found to be associated with the prognosis of clinical cancer patients. However, the intricate mechanisms by which UA affects the development and prognosis of tumor patients has not been well elucidated. In this study, we explored the role of UA in breast cancer, scrutinizing its impact on breast cancer cell function by treating two types of breast cancer cell lines with UA. The role of UA in the cell cycle and proliferation of tumors and the underlying mechanisms were further investigated. We found that the antioxidant effect of UA facilitated the scavenging of reactive oxygen species (ROS) in breast cancer, thereby reducing aryl hydrocarbon receptor (AhR) expression and affecting the breast cancer cell cycle, driving the proliferation of breast cancer cells through the AhR/p27Kip1/cyclin E1 pathway. Moreover, in breast cancer patients, the expression of AhR and its downstream genes may be closely associated with cancer progression in patients. Therefore, an increase in UA could promote the proliferation of breast cancer cells through the AhR/p27Kip1/cyclin E1 pathway axis.

Role for NLRP3 inflammasome-mediated, Caspase1-dependent response in glaucomatous trabecular meshwork cell death and regulation of aqueous humor outflow

PurposeAcute ocular hypertension (AOH) is the defining feature of acute glaucoma. The mechanical stress and excessive production of reactive oxygen species (ROS) during episodes can directly or indirectly damage the trabecular meshwork (TM). Despite its significance, a clear understanding of its pathogenesis and an effective therapeutic target remain lacking in acute glaucoma. In the present study, we explored the potential molecular mechanisms underlying TM cell death following oxidative damage and AOH. The use of NAC/VX-765 as a potential pharmaceutical intervention for reducing intraocular pressure (IOP) was discussed. MethodsThe levels of NLRP3 and caspase-1 were compared between normal and glaucomatous TM samples. An in vitro oxidative damage model and an AOH rat model were used to investigate the potential molecular mechanism behind TM cell death. The ROS scavenger N-acetyl-L-cysteine (NAC) and caspase-1 inhibitor VX-765 were used to counteract TM damage. ResultsElevated levels of NLRP3 and caspase-1 were observed in patients with acute glaucoma. H2O2 exposure decreased the viability of human trabecular meshwork (HTM) cells and increased intracellular ROS levels. Both Gene and protein expressions of NLRP3, caspase-1, GSDMD-N, and IL-1β were notably upregulated in H2O2-induced HTM cells and the rodent AOH model. Both NAC and VX-765 demonstrated protective effects against TM injury by inhibiting pyroptosis. The IOP-lowering effects of NAC and VX-765 persisted for 7 days. ConclusionsOur findings indicate that the classical pyroptosis pathway, NLRP3/caspase-1/IL-1β, plays a key role in acute glaucomatous TM injury. Targeting pyroptosis provides novel therapeutic avenues for treating AOH-induced irreversible TM injury. This provides not only a promising therapeutic target for glaucoma but also introduces a new approach to intervention.

Signaling Paradigms of H2S-Induced Vasodilation: A Comprehensive Review.

Hydrogen sulfide (H2S), a gas traditionally considered toxic, is now recognized as a vital endogenous signaling molecule with a complex physiology. This comprehensive study encompasses a systematic literature review that explores the intricate mechanisms underlying H2S-induced vasodilation. The vasodilatory effects of H2S are primarily mediated by activating ATP-sensitive potassium (K_ATP) channels, leading to membrane hyperpolarization and subsequent relaxation of vascular smooth muscle cells (VSMCs). Additionally, H2S inhibits L-type calcium channels, reducing calcium influx and diminishing VSMC contraction. Beyond ion channel modulation, H2S profoundly impacts cyclic nucleotide signaling pathways. It stimulates soluble guanylyl cyclase (sGC), increasing the production of cyclic guanosine monophosphate (cGMP). Elevated cGMP levels activate protein kinase G (PKG), which phosphorylates downstream targets like vasodilator-stimulated phosphoprotein (VASP) and promotes smooth muscle relaxation. The synergy between H2S and nitric oxide (NO) signaling further amplifies vasodilation. H2S enhances NO bioavailability by inhibiting its degradation and stimulating endothelial nitric oxide synthase (eNOS) activity, increasing cGMP levels and potent vasodilatory responses. Protein sulfhydration, a post-translational modification, plays a crucial role in cell signaling. H2S S-sulfurates oxidized cysteine residues, while polysulfides (H2Sn) are responsible for S-sulfurating reduced cysteine residues. Sulfhydration of key proteins like K_ATP channels and sGC enhances their activity, contributing to the overall vasodilatory effect. Furthermore, H2S interaction with endothelium-derived hyperpolarizing factor (EDHF) pathways adds another layer to its vasodilatory mechanism. By enhancing EDHF activity, H2S facilitates the hyperpolarization and relaxation of VSMCs through gap junctions between endothelial cells and VSMCs. Recent findings suggest that H2S can also modulate transient receptor potential (TRP) channels, particularly TRPV4 channels, in endothelial cells. Activating these channels by H2S promotes calcium entry, stimulating the production of vasodilatory agents like NO and prostacyclin, thereby regulating vascular tone. The comprehensive understanding of H2S-induced vasodilation mechanisms highlights its therapeutic potential. The multifaceted approach of H2S in modulating vascular tone presents a promising strategy for developing novel treatments for hypertension, ischemic conditions, and other vascular disorders. The interaction of H2S with ion channels, cyclic nucleotide signaling, NO pathways, ROS (Reactive Oxygen Species) scavenging, protein sulfhydration, and EDHF underscores its complexity and therapeutic relevance. In conclusion, the intricate signaling paradigms of H2S-induced vasodilation offer valuable insights into its physiological role and therapeutic potential, promising innovative approaches for managing various vascular diseases through the modulation of vascular tone.

MnO2 nanozyme boosts synergistic photodynamic/photothermal therapy of bacterial biofilm infections

As a near-infrared (NIR) adsorbing dye approved by the FDA, indocyanine green (ICG) can serve as an attractive therapeutic agent to combat biofilm infections through synergistic photodynamic therapy (PDT) and photothermal therapy (PTT) due to its deep-tissue penetration ability. However, ICG usually suffers from photo/thermal instability. Herein, to tackle the issues, bovine serum albumin (BSA) stabilized nanozyme MnO2 (BSA/MnO2) was synthesized by reducing manganese permanganate (KMnO4) with BSA, which was further loaded with ICG and coated with the positively charged hydroxypropyltrimethyl ammonium chloride chitosan (HACC) as the bacterial targeting moiety through noncovalent interactions. The constructed ICG@BSA/MnO2@HACC (IBMH) displays good photodynamic/thermal effects and bacterial targetability, enabling a synergistic PDT/PTT therapy against biofilm-associated infections. Compared with free ICG, IBMH exhibits enhanced photo/thermal stability owing to the O2-generating and photothermal capacities of MnO2, which significantly promotes biofilm phototherapy. Meanwhile, IBMH can effectively achieve anti-inflammatory effect due to the reactive oxygen species (ROS) scavenging capacity of nanozyme MnO2, thereby greatly accelerating wound healing after synergistic PDT/PTT. Both in vitro and in vivo assays solidly demonstrate its satisfactory anti-biofilm and anti-inflammatory effects. Therefore, our research proposes a promising and convenient strategy for developing multifunctional nanozyme for synergistic PDT/PTT of biofilm infection.

Using Hybrid MnO2-Au Nanoflowers to Accelerate ROS Scavenging and Wound Healing in Diabetes

Objectives: Excessive reactive oxygen species (ROS) in diabetic wounds are major contributors to chronic wounds and impaired healing, posing significant challenges in regenerative medicine. Developing innovative drug delivery systems is crucial to address these issues by modifying the adverse microenvironment and promoting effective wound healing. Methods: Herein, we designed a novel drug delivery platform using manganese dioxide nanoflower hybridized gold nanoparticle composites (MnO2-Au) synthesized via a hydrothermal reaction, and investigated the potential of MnO2-Au nanoflowers to relieve the high oxidative stress microenvironment and regulate diabetic wound tissue healing. Results: This hybrid material demonstrated superior catalytic activity compared to MnO2 alone, enabling the rapid decomposition of hydrogen peroxide and a substantial reduction in ROS levels within dermal fibroblasts. The MnO2-Au nanoflowers also facilitated enhanced dermal fibroblast migration and Col-I expression, which are critical for tissue regeneration. Additionally, a hydrogel-based wound dressing incorporating MnO2-Au nanoflowers was developed, showing its potential as an intelligent drug delivery system. This dressing significantly reduced oxidative stress, accelerated wound closure, and improved the quality of neonatal epithelial tissue regeneration in a diabetic rat skin defect model. Conclusions: Our findings underscore the potential of MnO2-Au nanoflower-based drug delivery systems as a promising therapeutic approach for chronic wound healing, particularly in regenerative medicine.

Platycodin D ameliorates polycystic ovary syndrome-induced ovarian damage by upregulating CD44 to attenuate ferroptosis

Recently, the potential association between polycystic ovary syndrome (PCOS) development and progression and ferroptosis has garnered attention. Increasing evidence suggests that targeting ferroptosis may be an effective strategy for treating PCOS. First, we observed that the expression of the ferroptosis regulatory molecules SLC7A11, GPX4, and FTH1 was decreased in the granulosa cells (GCs) of patients with PCOS and ovarian tissues of rats with PCOS; in contrast, TFR1 expression was increased. This suggests that GC ferroptosis is involved in PCOS pathogenesis. Furthermore, bioinformatics analysis of GC datasets from patients with PCOS and PCOS clinical samples and animal model analysis revealed CD44 as a key molecule regulating ferroptosis in PCOS, which was down-regulated in GCs of PCOS patients and rats. Subsequently, molecular docking was performed to screen existing natural compounds for inhibiting ferroptosis. Dynamic simulation and cellular thermal shift assay identified platycodin D as a natural plant extract for inhibiting ferroptosis by targeting CD44 in GCs. Subsequently, a series of functional experiments revealed that platycodin D ameliorated ovarian damage in rats with PCOS. This was primarily owing to the protective effects achieved by promoting glutathione production, attenuating lipid accumulation and lipid peroxidation in GCs, inhibiting iron overload, and scavenging reactive oxygen species. In addition, western blotting and immunofluorescence staining revealed that platycodin D upregulated the expression of CD44 and SLC7A11 in GCs. Furthermore, by knocking down CD44 and SLC7A11 in vivo and in vitro, respectively, the ameliorative effect of platycodin D on ferroptosis in the GCs of rats with PCOS was reversed. Collectively, these findings suggest that platycodin D attenuates ferroptosis in GCs by activating CD44/SLC7A11 axis, thereby upregulating system Xc−. In conclusion, platycodin D can attenuate ferroptosis in GCs by activating CD44, potentially ameliorating ovarian damage in PCOS.