Heme oxygenase-1/carbon monoxide: from basic science to therapeutic applications

Targeting oxidative stress in preeclampsia

Preeclampsia is a complex condition characterized by elevated blood pressure and organ damage involving kidneys or liver, resulting in significant morbidity and mortality for both the mother and the fetus. Increasing evidence suggests that oxidative stress, often caused by mitochondrial dysfunction within fetal trophoblast cells may play a major role in the development and progression of preeclampsia. Oxidative stress occurs as a result of an imbalance between the production of reactive oxygen species (ROS) and the capacity of antioxidant defenses, which can lead to placental cellular damage and endothelial cell dysfunction. Targeting oxidative stress appears to be a promising therapeutic approach that has the potential to improve both short- and long-term maternal and fetal outcomes, thus reducing the global burden of preeclampsia. The purpose of this review is to provide a comprehensive account of the mechanisms of oxidative stress in preeclampsia. Furthermore, it also examines potential interventions for reducing oxidative stress in preeclampsia, including natural antioxidant supplements, lifestyle modifications, mitochondrial targeting antioxidants, and pharmacological agents.A better understanding of the mechanism of action of proposed therapeutic strategies targeting oxidative stress is essential for the identification of companion biomarkers and personalized medicine approaches for the development of effective treatments of preeclampsia.

Macrophage biology in the pathogenesis of Helicobacter pylori infection

Infection with H. pylori induces chronic gastric inflammation, progressing to peptic ulcer and stomach adenocarcinoma. Macrophages function as innate immune cells and play a vital role in host immune defense against bacterial infection. However, the distinctive mechanism by which H. pylori evades phagocytosis allows it to colonize the stomach and further aggravate gastric preneoplastic pathology. H. pylori exacerbates gastric inflammation by promoting oxidative stress, resisting macrophage phagocytosis, and inducing M1 macrophage polarization. M2 macrophages facilitate the proliferation, invasion, and migration of gastric cancer cells. Various molecular mechanisms governing macrophage function in the pathogenesis of H. pylori infection have been identified. In this review, we summarize recent findings of macrophage interactions with H. pylori infection, with an emphasis on the regulatory mechanisms that determine the clinical outcome of bacterial infection.

Current developments of pharmacotherapy targeting heme oxygenase 1 in cancer (Review)

Malignant tumors are non-communicable diseases that impact human health and quality of life. Identifying and targeting the underlying genetic drivers is a challenge. Heme oxygenase-1 (HO-1), a stress-inducible enzyme also known as heat shock protein 32, plays a crucial role in maintaining cellular homeostasis. It mitigates oxidative stress-induced damage and exhibits anti-apoptotic properties. HO-1 is expressed in a wide range of malignancies and is associated with tumor growth. However, the precise role of HO-1 in tumor development remains controversial. Drugs, both naturally occurring and chemically synthesized, can inhibit tumor growth by modulating HO-1 expression in cancer cells. The present review aimed to discuss biological functions of HO-1 pharmacological therapies targeting HO-1.

In Situ 3D SERS Imaging of CO2 Reduction in Living Cells

The advancement of catalytic processes for therapeutic applications is pivotal to the development of next-generation medical technologies. One of the major challenges in this field lies in elucidating the intracellular generation of small molecules, such as carbon monoxide (CO), nitric oxide (NO), and others, which possess significant therapeutic potential. In this study, in situ surface-enhanced Raman spectroscopy (SERS) is employed to visualize and monitor the carbon dioxide (CO2) reduction process mediated by a rhenium coated gold nanoflower (Re@Au) catalyst within living cells. The findings provide direct spectroscopic evidence of CO2 reduction under intracellular conditions, demonstrating that CO can be catalytically generated from CO2 in the cellular environment. These results position SERS as an indispensable tool for investigating catalytic processes in biological systems, providing molecular-level insights through the analysis of molecular fingerprint spectra that are typically beyond the capabilities of conventional microscopy techniques.

Carbon monoxide inhibits human bronchial epithelial CCL5 and IL-6 secretion induced by SARS-CoV-2 spike RBD protein

Carbon monoxide (CO) is a novel anti-inflammatory molecule, but the effects of CO on SARS-CoV-2 spike RBD (S-RBD)-induced human bronchial epithelial cytokines release remains unclear. CO was delivered using CO-releasing molecule 3 (CORM-3). The effects of S-RBD, ATPγS and CO on cytokines secretion were determined by enzyme-linked immunosorbent assay (ELISA) in 16HBE14o-human bronchial epithelial cell line. The inhibitory effect of CO on S-RBD-induced ERK phosphorylation was assessed by Western blot analysis. The regulatory effect of CO on extracellular nucleotide-induced ion transport was quantified by short-circuit current (ISC). S-RBD evoked CCL5 and IL-6 release and this effect could be suppressed by CO. However, CO failed to inhibit ATP release induced by S-RBD while decreased ATP-induced CCL5 and IL-6 secretion as well as ion transport. Furthermore, CO significantly inhibited ERK phosphorylation induced by S-RBD. These findings suggest an anti-inflammatory role of CO during inflammation induced by S-RBD and extracellular nucleotide in human bronchiol epithelial cells.

A novel mitochondria-targeted near-infrared metal-free fluorescence probe for detecting carbon monoxide in atherosclerosis

The early stage of atherosclerosis (AS) is characterized by explosion of reactive oxygen species (ROS) in mitochondria and inflammatory reaction, and then abundant ROS further promote the progress of AS. As an endogenous signal biomolecule with antioxidant properties, carbon monoxide (CO) is enriched in mitochondria to combat oxidative stress, thereby significantly increasing during the pathogenesis of AS. However, there is currently no mitochondria-targeted near-infrared fluorescence probe for detecting CO in atherosclerosis. In this paper, we use a mitochondrion-targeting metal-free near-infrared fluorescence probe, AS-CO, for investigating AS via detecting and mapping the fluctuations of CO with enhanced sensitivity and selectivity. In addition, probe AS-CO can be positioned at mitochondria. It has also proven effective in detecting both internally and externally sourced CO in HUVEC cells. More importantly, using AS-CO, for the first time, we provided the visualization evidence of endogenous CO generation in the aorta of mice that induced AS by high-fat diet (HFD) and further investigated the protective effects of (-)-epicatechin gallate (ECG) against HFD-induced AS. The results demonstrated the feasibility of AS-CO for monitoring and evaluating personalized treatment of AS.

In utero and early-life nitrate in drinking water impacts lung function of weanling rats

Consumption of nitrate in drinking water has previously been associated with a range of adverse health effects, including methemoglobinemia and potentially cancer. In animal models, it has been shown to impact respiratory structure and function, however, there is a paucity of data of the effects of in utero exposure on the respiratory health of offspring. In this study, pregnant rats were given drinking water containing nitrate at 50 or 100 mg/L (or control). At three weeks of age, we assessed a range of respiratory health outcomes, including lung function, pulmonary inflammation and lung structure, in the offspring of both sexes. Nitrate exposure was associated with minor adverse effects on lung function, including an increase in airway resistance at functional residual capacity in male offspring, but there were no significant changes in lung structure. Our results suggest that in utero / early-life exposure to nitrates in drinking water at levels relevant to human exposure is unlikely to have significant negative impacts on offspring respiratory health.

Exhaled carbon monoxide: variations due to collection method and physiology

The measurement of exhaled carbon monoxide (eCO) is relevant to understanding normal physiology and disease states but has been limited by deficiencies in valid sampling protocols, accurate and feasible measurement methods, and the understanding of normal physiological variation. The purposes of this study were (1) to compare the three collection methods for eCO and (2) to gain a better understanding of patterns of normal variation by obtaining repeated daily and weekly measurements. We compared three techniques to sample eCO: continuous breathing(ConB), breath-holding(BrH), and short rebreathing (SrB). We used a Carbolyzer mBA-2000 instrument that involves an electrochemical method to quantify CO, with the final value corrected for ambient CO. InPhase I, we comparedConBwithBrHin 10 healthy non-smokers (5 male, five female). On day 1, the eCO was determined from 07:30 to 17:00 (11 samples), and the first four morning time points were repeated on days 7, 14, and 21.ConBhad a lower eCO thanBrH,and eCO2was frequently below the threshold of 4.6% compatible with inadequate alveolar sampling. The eCO measured by theConBandBrHmethods increased during the day and showed week-to-week variability. InPhase II, we compared theBrHandSrBtechniques by collecting prebreakfast samples weekly for four weeks in 30 healthy non-smokers (15 male,15 female). Comparing theSrBvs. theBrHmethod,SrBwas the easier for the participants to perform, generated higher eCO (∼ 0.5 ppm), and produced higher eCO2 levels (5.2% ± 0.3 vs. 5.0% ± 0.2); Importantly,Phase IIstudy revealed that week-to-week changes in prebreakfast fasting eCO for individual participants were ⩾1.0 ppm in ∼ 37%. This variability complicates the interpretation of the relationship between small changes in eCO and the underlying physiological or disease states.

Oxidative Stress Biomarkers in Laryngeal Squamous Cell Carcinoma and Their Clinical Implications: Preliminary Results

Background/Objectives: Laryngeal squamous cell carcinoma represents one of the most common head and neck cancers with a five-year survival rate that, despite diagnostic and therapeutic advances, has not shown any significant improvement in recent decades. Oxidative stress, generated by an imbalance between reactive oxygen species and cellular antioxidant systems, is considered a central mechanism in the carcinogenesis of laryngeal squamous cell carcinoma, causing DNA damage and genomic alterations. Methods: This prospective observational paired case-control study focused on the evaluation of antioxidant proteins, such as superoxide dismutase, catalase, heme-oxygenase 1, vimentin, metallothionein, and nuclear factor erythroid 2-related factor 2, in cancer tissues from fifteen patients with laryngeal squamous cell carcinoma, using adjacent healthy tissues as controls. Results: The results show a statistically significant overexpression of all proteins analyzed in cancer tissues compared to controls, with relevant correlations between specific biomarkers and clinical characteristics, age, sex, smoking habits, and degree of tumor differentiation. Conclusions: These preliminary studies, while limited by sample size and the complexity of molecular regulation, indicate that the overexpression of antioxidant enzymes in laryngeal squamous cell carcinoma tissues, along with their correlations with key clinical parameters, underscores a context-dependent role of oxidative stress in tumor progression. A deeper understanding of oxidative stress mechanisms could contribute to advance personalized management strategies for laryngeal squamous cell carcinoma, potentially improving treatment outcomes and patient prognosis.

Heme Regulatory Motif of Heme Oxygenase-2 Is Involved in the Interaction with NADPH-Cytochrome P450 Reductase and Regulates Enzymatic Activity

Mammalian heme oxygenase (HO) catalyzes heme degradation using reducing equivalents supplied by NADPH-cytochrome P450 reductase (CPR). The tertiary structure of the catalytic domain of a constitutively expressed isoform of HO, HO-2, resembles that of the inductive isoform, HO-1, whereas HO-2 has two heme regulatory motifs (HRM) at the proximal portion of the C-terminus, where the disulfide linkage reflects cellular redox conditions and the second heme binding site is located. Here, we report the results of crosslinking experiments, which suggest that HRM is located near the FMN-binding domain of the CPR when it is complexed with HO-2. The enzymatic assay and reduction kinetics results suggest that heme-bound HRM negatively regulates HO-2 activity in vitro. Cellular redox conditions and free heme concentrations may regulate HO-2 activity.

Chronic unpredictable stress exposure disrupts testicular function by modulating germ cell-junctional dynamics and Nrf2/HO-1/IKKβ/NF-κB pathway

The unpredictable nature of stress complicates understanding its relationship with male infertility. In this study, we investigated testicular germ cell and junctional dynamics in male mice following exposure to chronic unpredictable stress (CUS). Adult Parkes male mice were exposed to CUS for 35 days (one complete spermatogenic cycle), with a random stressor (restraint stress, water deprivation, food deprivation, light flashing, wet bedding, cage shaking, or cage tilting) applied once per day in an intermittent and unpredictable manner to avoid repeating the same stimulus on consecutive days. CUS exposure caused behavioral alterations in mice, as observed through the forced swim test and the tail suspension test. CUS inhibited testosterone biosynthesis by decreasing steroidogenic markers (SF-1, StAR, 3β-HSD, and 17β-HSD). It also resulted in altered oxido-inflammatory and apoptotic markers, including increased LPO, Caspase-3, IKKβ, and NF-κB, along with decreased Nrf2, HO-1, SOD, and catalase in the testis. CUS exposure reduced 1 C and 4 C germ cell populations and decreased germ cell ratios (1 C:2 C, 4 C:2 C, and 4 C:S-phase), impairing sperm development. CUS disrupted meiosis initiation, chromosomal synapsis, and germ cell maintenance by reducing Stra8, SYCP3, and Piwil1 expression in the testis. It also adversely affected blood-testis barrier markers, such as ZO-1 and connexin43. These changes led to altered testicular histomorphology, reduced daily sperm production, and disrupted germ cell dynamics. The findings suggest that CUS inhibits steroidogenesis and perturbs the Nrf2/HO-1/IKKβ/NF-κB oxido-inflammatory pathway. This leads to disrupted germ cell dynamics, compromised blood-testis barrier integrity, altered histomorphology, and reduced sperm production, collectively resulting in testicular dysfunction.

The Heme Oxygenase/Biliverdin Reductase System and Its Genetic Variants in Physiology and Diseases

Heme oxygenase (HO) metabolizes heme into ferrous iron, carbon monoxide (CO), and biliverdin-IXα (BV), the latter being reduced into bilirubin-IXα (BR) by the biliverdin reductase-A (BVR). Heme oxygenase exists as two isoforms, HO-1, inducible and involved in the cell stress response, and HO-2, constitutive and committed to the physiologic turnover of heme and in the intracellular oxygen sensing. Many studies have identified genetic variants of the HO/BVR system and suggested their connection in free radical-induced diseases. The most common genetic variants include (GT)n dinucleotide length polymorphisms and single nucleotide polymorphisms. Gain-of-function mutations in the HO-1 and HO-2 genes foster the ventilator response to hypoxia and reduce the risk of coronary heart disease and age-related macular degeneration but increase the risk of neonatal jaundice, sickle cell disease, and Parkinson's disease. Conversely, loss-of-function mutations in the HO-1 gene increase the risk of type 2 diabetes mellitus, chronic obstructive pulmonary disease, and some types of cancers. Regarding BVR, the reported loss-of-function mutations increase the risk of green jaundice. Unfortunately, the physiological role of the HO/BVR system does not allow for the hypothesis gene silencing/induction strategies, but knowledge of these mutations can certainly facilitate a medical approach that enables early diagnoses and tailored treatments.

HMOX1 as a potential drug target for upper and lower airway diseases: insights from multi-omics analysis

BACKGROUND

Oxidative stress is key in inflammatory airway diseases. Heme oxygenase 1 (HMOX1) regulates oxidative stress, but its role in airway diseases needs exploration.

METHODS

Differentially expressed genes (DEGs) between healthy nasal mucosa and chronic rhinosinusitis with nasal polyps (CRSwNP) were identified from Gene Expression Omnibus (GEO). Candidate genes were further screened using Gene Set Enrichment Analysis (GSEA) and Random Forest (RF) algorithms. Causal inference between candidate genes and upper and lower airway diseases (CRSwNP, allergic rhinitis (AR), and asthma (AS)) was conducted using bidirectional two-sample Mendelian randomization (TwoSampleMR) analysis. Single-cell RNA sequencing (scRNA-seq) data were used to determine the cellular localization and intercellular interactions of candidate genes. Molecular docking was used to identify potential therapeutic agents.

RESULTS

HMOX1 expression was significantly elevated in CRSwNP. TwoSampleMR analysis indicated a negative causal relationship between HMOX1 exposure and the occurrence of upper and lower airway diseases (CRSwNP [(odds ratio (OR)/95% confidence interval (CI): 0.945/(0.893-0.999), P = 0.044], AR [OR/95% CI: 0.997/(0.994-0.999), P = 0.007], and AS [OR/95% CI: 0.935/(0.895-0.977), P = 0.003]). scRNA-seq data revealed HMOX1 localization in M2 macrophages. Molecular docking identified 15 antioxidants, including Acetylcysteine and Quercetin, that can upregulate HMOX1 expression.

CONCLUSION

HMOX1 may have a protective role in the pathogenesis of upper and lower airway diseases (CRSwNP, AR, and AS) by modulating oxidative stress. Antioxidants that increase HMOX1 expression could offer new therapeutic avenues for these diseases.

CLINICAL TRIAL

Not applicable.

The HELP-UnaG Fusion Protein as a Bilirubin Biosensor: From Theory to Mature Technological Development

HUG is the HELP-UnaG recombinant fusion protein featuring the typical functions of both HELP and UnaG. In HUG, the HELP domain is a thermoresponsive human elastin-like polypeptide. It forms a shield enwrapping the UnaG domain that emits bilirubin-dependent fluorescence. Here, we recapitulate the technological development of this bifunctional synthetic protein from the theoretical background of its distinct protein moieties to the detailed characterization of its macromolecular and functional properties. These pieces of knowledge are the foundations for HUG production and application in the fluorometric analysis of bilirubin and its congeners, biliverdin and bilirubin glucuronide. These bile pigments are metabolites that arise from the catabolism of heme, the prosthetic group of cytochromes, hemoglobin and several other intracellular enzymes engaged in electron transfer, oxygen transport and protection against oxygen free radicals. The HUG assay is a powerful, user-friendly and affordable analytical tool that alone supports research at each level of complexity or taxonomy of living entities, from enzymology, cell biology and pathophysiology to veterinary and clinical sciences.

SQSTM1 upregulation-induced iron overload triggers endothelial ferroptosis in nicotine-exacerbated atherosclerosis

AIMS

Nicotine-exacerbated atherosclerosis significantly increases global mortality. Endothelial cells, which line the interior of blood vessels, are crucial for maintaining vascular function. How nicotine is involved in vascular remodeling in atherosclerosis via modulating endothelial dysfunction remains unknown.

MATERIALS AND METHODS

Comprehensive gene expression analyses identified key genes upregulated in the ferroptosis pathway in smoking-exacerbated atherosclerosis. Predictive models integrating these ferroptosis-related genes were constructed to differentiate atherosclerotic plaques.

KEY FINDINGS

Here, we reveal that ferroptosis mediates nicotine-induced endothelial dysfunction, exacerbating atherosclerosis. Mechanistically, nicotine elevates sequestosome 1 (SQSTM1), leading to iron overload and an increase in reactive oxygen species (ROS) and the levels of ferroptosis markers heme-oxygenase 1 (HMOX1) and prostaglandin-endoperoxide synthase 2 (PTGS2), contributing to ferroptosis in endothelial cells and the aberrant production of inflammatory factors. Pharmacological inhibition of ferroptosis and normalization of iron levels by knocking down SQSTM1 mitigate endothelial ferroptosis and reduce production of pro-inflammatory factors. Diagnostically, human plasma levels of HMOX1, SQSTM1, and PTGS2 are elevated in smokers with atherosclerosis but reduce in ex-smokers. Predictive models, including a support vector machine integrating these ferroptosis-related genes, effectively differentiate between early- and advanced-stage atherosclerotic plaques.

SIGNIFICANCE

SQSTM1 upregulation-induced iron overload triggers endothelial ferroptosis in nicotine-exacerbated atherosclerosis, suggesting excellent predictive efficacy for atherosclerosis development and potential for clinical applications.

TRIAL REGISTRATION

This study has been registered in the Chinese Clinical Trial Registry (ChiCTR2400083484, Registration Date: April 26, 2024).

Tumor microenvironment-responsive engineered hybrid nanomedicine for photodynamic-immunotherapy via multi-pronged amplification of reactive oxygen species

Reactive oxygen species (ROS) is promising in cancer therapy by accelerating tumor cell death, whose therapeutic efficacy, however, is greatly limited by the hypoxia in the tumor microenvironment (TME) and the antioxidant defense. Amplification of oxidative stress has been successfully employed for tumor therapy, but the interactions between cancer cells and the other factors of TME usually lead to inadequate tumor treatments. To tackle this issue, we develop a pH/redox dual-responsive nanomedicine based on the remodeling of cancer-associated fibroblasts (CAFs) for multi-pronged amplification of ROS (ZnPP@FQOS). It is demonstrated that ROS generated by ZnPP@FQOS is endogenously/exogenously multiply amplified owing to the CAFs remodeling and down-regulation of anti-oxidative stress in cancer cells, ultimately achieving the efficient photodynamic therapy in a female tumor-bearing mouse model. More importantly, ZnPP@FQOS is verified to enable the stimulation of enhanced immune responses and systemic immunity. This strategy remarkably potentiates the efficacy of photodynamic-immunotherapy, thus providing a promising enlightenment for tumor therapy.

Heme oxygenase 1 inhibitor discovery and formulation into nanostructured lipid carriers as potent and selective treatment against triple negative metastatic breast cancer

Heme oxygenase-1 (HO-1) has been identified as a potential new target in anticancer therapy, being overexpressed in different tumors and crucial for cell proliferation. Advances in the development of specific HO-1 inhibitors should support the understanding of controlling HO-1 activity as antitumoral strategies, opening the path for future therapeutic applications. In the present study, small series of new HO-1 inhibitors were synthesized by joining a butylimidazolic pharmacophore together with a hydrophobic moiety spaced by a 2-oxybenzamide central linker. The most active and selective HO-1 inhibitor, VP 21-04, 2-(4-(1H-imidazol-1-yl)butoxy)-N-benzyl-5-iodobenzamide (7b) was identified. This ligand showed strong cytotoxic activity against melanoma and breast cancer cell lines. Encapsulation of VP 21-04 in nanostructured lipid carriers (NLC 21-04) was performed to exploit its therapeutic potential by passive-targeting delivery ameliorating water-solubility and toxicity. Interestingly, NLC 21-04 showed a marked antiproliferative effect in both cancer cell lines, and an improved safety profile with a wider therapeutic window when compared to the free drug. Finally, NLC 21-04 showed a marked tumor growth reduction while being safe in an in ovo tumor model, highlighting the therapeutic potential of the developed nanoparticles against triple negative metastatic breast cancer.

Association of blood carboxyhemoglobin levels with mortality and neurological outcomes in out-of-hospital cardiac arrest

Background

Carbon monoxide (CO), produced endogenously by heme oxygenase-1, plays a crucial role in the immune system by mitigating cellular damage under stress. However, the significance of carboxyhemoglobin (COHb) levels after out-of-hospital cardiac arrest (OHCA) is not well understood. This study aimed to explore the association between COHb levels at hospital arrival and within the first 24 h post-arrival with 30-day mortality and neurological outcomes in patients who experienced OHCA.

Methods

This single-center, retrospective study analyzed data from adult patients who experienced OHCA seen at Okayama University Hospital from 2019 to 2023. The patients were assigned to one of two study groups based on COHb levels (0.0% or ≥0.1%) upon hospital arrival. The primary outcome was 30-day mortality.

Results

Among the 560 eligible patients who experienced OHCA, 284 (50.7%) were in the COHb 0.0% group and 276 (49.3%) were in the COHb ≥ 0.1% group. The 30-day mortality was significantly higher in the COHb 0.0% group compared to the COHb ≥ 0.1% group (264 [92.9%] vs. 233 [84.4%]). Multivariable logistic regression showed that the COHb 0.0% group was associated with 30-day mortality (adjusted ORs: 2.24, 95% CIs: 1.10-4.56). Non-survivors at 30 days who were admitted to the intensive care unit had lower COHb levels at hospital arrival (0.0% vs. 0.2%) and lower mean COHb levels during the first 24 h post-arrival (0.7% vs. 0.9%) compared to survivors.

Conclusions

COHb levels of 0.0% were linked to worse outcomes in patients experiencing OHCA, warranting further research on the prognostic implications of COHb in this context.

HO-1: An emerging target in fibrosis

Fibrosis, an aberrant reparative response to tissue injury, involves a disruption in the equilibrium between the synthesis and degradation of the extracellular matrix, leading to its excessive accumulation within normal tissues, and culminating in organ dysfunction. Manifesting in the terminal stages of nearly all chronic ailments, fibrosis carries a high mortality rate and poses a significant threat to human health. Heme oxygenase-1 (HO-1) emerges as an endogenous protective agent, mitigating tissue damage through its antioxidant, anti-inflammatory, and antiapoptotic properties. Numerous studies have corroborated HO-1's potential as a therapeutic target in anti-fibrosis treatment. This review delves into the structural and functional attributes, and the upstream and downstream pathways of HO-1. Additionally, the regulatory networks and mechanisms of HO-1 in cells associated with fibrosis are elucidated. The role of HO-1 in various fibrosis-related diseases is also explored. Collectively, this comprehensive information serves as a foundation for future research and augments the viability of HO-1 as a therapeutic target for fibrosis.

Protein hydrolysates from Hermetia illucens trigger cellular responses to cope with LPS-induced inflammation and oxidative stress in L-929 cells

Insect protein hydrolysates (PH) are emerging as valuable compounds with biological activity. The aim of the present study was to assess the potential cytoprotective effects of PH from the Black Soldier Fly (BPH, in the range 0.1-0.5 mg/mL) against inflammatory conditions and oxidative stress in LPS-challenged L-929 cells. BPH was effective in inhibiting LPS-induced ROS and nitrite production and in reducing the protein and transcript levels of remarkable inflammatory markers, such as TNF-α, IL-6, IL-1α, and IL-1β, as determined by ELISA and/or qPCR. Moreover, the BPH antioxidant and anti-inflammatory activities rely on the induction of selected genes and proteins involved in the antioxidant response (i.e. Cu/ZnSod, MnSod, Gpx, HO-1) through Nrf2, as well as on the inhibition of the activation of NF-κB, a key player in inflammation. These findings suggest that BPH represents effective bioactive compounds with therapeutic potential for mitigating oxidative stress and inflammation in vitro, thus deserving further investigation into the underlying mechanisms before BPH application as novel drugs in the near future.

CO-loaded hemoglobin/EGCG nanoparticles functional coatings for inflammation modulation of vascular implants

During the implantation process of cardiovascular implants, vascular damage caused by inflammation occurs, and the inflammatory process is accompanied by oxidative stress. Currently, carbon monoxide (CO) has been demonstrated to exhibit various biological effects including vasodilatation, antithrombotic, anti-inflammatory, apoptosis-inducing and antiproliferative properties. In this study, hemoglobin/epigallocatechin-3-gallate (EGCG) core-shell nanoparticle-containing coating on stainless steel was prepared for CO loading and inflammation modulation. Inspired by strong coordination ability with CO, hemoglobin nanoparticle was first prepared and encapsulated into EGCG metal-phenolic networks. A polydopamine (PDA) linking layer was then coated on 316 stainless steel, and the hemoglobin/EGCG nanoparticles were loaded with the subsequent PDA deposition. It showed that the maximum release amount of CO by the coating was 17.0 nmol/cm2 in 48 h. In vitro evaluations conducted in a simulated inflammatory environment revealed that the coating, which released CO from hemoglobin/EGCG nanoparticles, effectively mitigated the lipopolysaccharide-induced inflammatory response in macrophages. Specifically, it decreased the expression of tumor necrosis factor-α, increased the expression of interleukin-10, suppressed the polarization of macrophages toward the M1 phenotype and reduced intracellular reactive oxygen species (ROS). Furthermore, under simulated oxidative stress conditions, the coating decreased the apoptosis of endothelial cells induced by oxidative stress and down-regulated intracellular ROS levels. In vivo implantation results further confirmed that the coating, with its hemoglobin/EGCG nanoparticles and CO release capabilities, reduced macrophage-mediated inflammatory responses and modulated the polarization phenotype of macrophages.

Reduction in Renal Heme Oxygenase-1 Is Associated with an Aggravation of Kidney Injury in Shiga Toxin-Induced Murine Hemolytic-Uremic Syndrome

Hemolytic-uremic syndrome (HUS) is a systemic complication of an infection with Shiga toxin (Stx)-producing enterohemorrhagic Escherichia coli, primarily leading to acute kidney injury (AKI) and microangiopathic hemolytic anemia. Although free heme has been found to aggravate renal damage in hemolytic diseases, the relevance of the heme-degrading enzyme heme oxygenase-1 (HO-1, encoded by Hmox1) in HUS has not yet been investigated. We hypothesized that HO-1, also important in acute phase responses in damage and inflammation, contributes to renal pathogenesis in HUS. The effect of tamoxifen-induced Hmox1 gene deletion on renal HO-1 expression, disease progression and AKI was investigated in mice 7 days after HUS induction. Renal HO-1 levels were increased in Stx-challenged mice with tamoxifen-induced Hmox1 gene deletion (Hmox1R26Δ/Δ) and control mice (Hmox1lox/lox). This HO-1 induction was significantly lower (-43%) in Hmox1R26Δ/Δ mice compared to Hmox1lox/lox mice with HUS. Notably, the reduced renal HO-1 expression was associated with an exacerbation of kidney injury in mice with HUS as indicated by a 1.7-fold increase (p = 0.02) in plasma neutrophil gelatinase-associated lipocalin (NGAL) and a 1.3-fold increase (p = 0.06) in plasma urea, while other surrogate parameters for AKI (e.g., periodic acid Schiff staining, kidney injury molecule-1, fibrin deposition) and general disease progression (HUS score, weight loss) remained unchanged. These results indicate a potentially protective role of HO-1 in the pathogenesis of Stx-mediated AKI in HUS.

Phosphorus-independent role of FGF23 in erythropoiesis and iron homeostasis

A number of studies have reported an association between phosphorus, red blood cell (RBC) production, and iron metabolism. However, it is difficult to distinguish whether the effect of phosphorus is direct or through the actions of FGF23, and it is not clear whether phosphorus is positively or negatively associated with RBC production. In the present study, we investigated the effects of a) increased phosphorus load and b) phosphorus deficiency on erythropoiesis and iron metabolism in association with FGF23. Mice were fed either a 1.2% or 1.65% phosphorus diet and compared to mice fed a control diet containing 0.6% of phosphorus. Moreover, we used two mouse models of hypophosphatemia-induced either by dietary intervention in the form of a low phosphorus (LP) diet (0.02% of Pi) or genetically in a mouse model of X-linked hypophosphatemia (XLH)-that had opposite FGF23 levels. Phosphorus supplementation appropriately increased FGF23 levels leading to excretion of excess phosphorus and normalization of serum phosphorus levels. We also found that a phosphorus-rich diet results in inflammation-induced hypoferremia associated with reduced iron export leading to tissue iron overload. Moreover, high phosphorus intake results in ineffective erythropoiesis caused by decreased production (decreased RBCs, hemoglobin, hematocrit, and erythroid progenitors in the bone marrow) and increased destruction of RBCs, leading to anemia despite increased EPO secretion. These complications occur through the actions of elevated FGF23 in the presence of normophosphatemia. Our data also show that LP diet induces a decrease in the serum concentrations of phosphorus and FGF23, resulting in increased RBC counts, hemoglobin concentration, and hematocrit compared to mice fed normal diet. Moreover, serum iron and transferrin saturation were increased and positively correlated with serum ferritin, liver ferritin protein and mRNA expression in mice fed LP diet. However, hyp mice, the murine model of XLH, exhibit hypophosphatemia and high serum FGF23 levels, along with low number of circulating RBCs, hemoglobin, and hematocrit compared to wild-type mice. In the bone marrow, hyp mice showed reduced number of erythroid progenitors and formed significantly less BFU-E colonies compared to control mice. Serum iron levels and transferrin saturation were also decreased in hyp mice in comparison to control mice. Taken together, our data show that FGF23 acts independent of phosphorus levels to regulate erythropoiesis and iron homeostasis.

Activation of cannabinoid receptor 2 by turmeric oleoresin reduces inflammation and oxidative stress in an osteoarthritis in vitro model

Introduction

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by the progressive degradation of articular cartilage, resulting in pain and reduced mobility. Turmeric (Curcuma longa L.) has been widely recognized for its anti-inflammatory and antioxidant properties, but the molecular mechanisms underlying its therapeutic effects remain inadequately explored. This study investigates the potential of turmeric oleoresin (TUR) to activate Cannabinoid Receptor 2 (CBR2) and its role in mediating anti-inflammatory and antioxidant effects in an in vitro OA model.

Material and methods

Molecular docking and cAMP quantification assays were used to evaluate TUR's agonistic activity on CBR2. Human chondrosarcoma cells (SW-1353) were treated with TUR under oxidative stress induced by menadione or inflammatory conditions simulated with IL-1β and TNF-α. The effects of TUR were assessed in the presence and absence of the CBR2 antagonist SR144528. Outcomes included changes in reactive oxygen species (ROS) production, inflammatory marker expression, oxidative defense markers and endocannabinoid system components and receptors.

Results

TUR was confirmed as a CBR2 agonist and significantly reduced ROS production, downregulated pro-inflammatory cytokines (IL-6, COX-2, metalloproteases), and suppressed signaling pathways such as NFKB1, ERK 1/2, and c-Myc. These effects were reversed upon CBR2 inhibition. TUR also enhanced HMOX-1 expression and modulated endocannabinoid-related enzymes, highlighting its impact on oxidative stress and the endocannabinoid system.

Discussion

These findings suggest that CBR2 activation is central to TUR's anti-inflammatory and antioxidant effects. By modulating key pathways and endocannabinoid system components, TUR demonstrates potential as a novel therapeutic agent for OA management. Future studies could explore its clinical applications and further validate its molecular mechanisms in vivo.

Cardiac surgery-associated acute kidney injury in cardiopulmonary bypass: a focus on sex differences and preventive strategies

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a high-risk complication with well-recognized increased morbidity and mortality after cardiac surgery attributable in large part to cardiopulmonary bypass (CPB)-associated factors contributing to AKI including hemodilution, hypothermia, hypotension, and exposure to artificial surfaces. These conditions disrupt the renal microcirculation and activate local and systemic inflammatory responses to nonpulsatile flow and low perfusion pressure. The underlying mechanisms of CSA-AKI in CPB are not fully understood, and the incidence of CSA-AKI remains high at around 30%. Furthermore, women appear to be more vulnerable than men to the renal injury associated with CPB even though the overall incidence of cardiovascular and kidney diseases is lower in premenopausal women. Nevertheless, estrogen elicits renoprotective effects in several ways including mitigating inflammation, promoting natriuresis, and endothelial protection as shown in preclinical studies. However, women have higher rates of CSA-AKI and these are exacerbated in postmenopausal women. This leads to the conundrum of whether sex, age, and hormonal status differences influence CSA-AKI. In this review, we briefly discuss the pathophysiology of CSA-AKI in CPB and sex differences in kidney functions with a focus on the possible role of estrogen-specific effects in CPB and also possible differences in CPB in women including greater hemodilution. Furthermore, we review strategies to prevent CSA-AKI in CPB with a highlight for potential sex-specific strategies. Improving our understanding of the impact of sex and sex hormones on CSA-AKI initiation and development will allow us to better manage the CPB strategies delivered to all patients.

The Neural Palette of Heme: Altered Heme Homeostasis Underlies Defective Neurotransmission, Increased Oxidative Stress, and Disease Pathogenesis

Heme, a complex iron-containing molecule, is traditionally recognized for its pivotal role in oxygen transport and cellular respiration. However, emerging research has illuminated its multifaceted functions in the nervous system, extending beyond its canonical roles. This review delves into the diverse roles of heme in the nervous system, highlighting its involvement in neural development, neurotransmission, and neuroprotection. We discuss the molecular mechanisms by which heme modulates neuronal activity and synaptic plasticity, emphasizing its influence on ion channels and neurotransmitter receptors. Additionally, the review explores the potential neuroprotective properties of heme, examining its role in mitigating oxidative stress, including mitochondrial oxidative stress, and its implications in neurodegenerative diseases. Furthermore, we address the pathological consequences of heme dysregulation, linking it to conditions such as Alzheimer's disease, Parkinson's disease, and traumatic brain injuries. By providing a comprehensive overview of heme's multifunctional roles in the nervous system, this review underscores its significance as a potential therapeutic target and diagnostic biomarker for various neurological disorders.

Protective Role of Cepharanthine Against Equid Herpesvirus Type 8 Through AMPK and Nrf2/HO-1 Pathway Activation

Equid herpesvirus type 8 (EqHV-8) is known to cause respiratory disease and miscarriage in horses and donkeys, which is a major problem for the equine farming industry. However, there are currently limited vaccines or drugs available to effectively treat EqHV-8 infection. Therefore, it is crucial to develop new antiviral approaches to prevent potential pandemics caused by EqHV-8. This study evaluates the antiviral and antioxidant effects of cepharanthine against EqHV-8 by employing both in vitro assays and in vivo mouse models to assess its therapeutic efficacy. To assess the effectiveness of cepharanthine against EqHV-8, we conducted experiments using NBL-6 and RK-13 cells. Additionally, we developed a mouse model to validate cepharanthine's effectiveness against EqHV-8. In our in vitro experiments, we assessed the cepharanthine's ability to inhibit infection caused by EqHV-8 in NBL-6 and RK-13 cells. Our results demonstrated that cepharanthine has a dose-dependent inhibitory effect, indicating that it possesses anti-EqHV-8 properties at the cellular level. Moreover, we investigated the mechanism through which cepharanthine exerts its protective effects. It was observed that cepharanthine effectively reduces the oxidative stress induced by EqHV-8 by activating the AMPK and Nrf2/HO-1 signaling pathways. Furthermore, when administered to EqHV-8 infected mice, cepharanthine significantly improved lung tissue pathology and reduced oxidative stress. The findings presented herein collectively highlight cepharanthine as a promising candidate for combating EqHV-8 infections.

Imbalance of redox homeostasis and altered cellular signaling induced by the metal complexes of terpyridine

Compounds that can induce oxidative stress in cancer cells while remaining nontoxic to healthy cells are extremely promising for potential anticancer drugs. 2,2':6',2''-terpyridine-metal complexes possess these properties. The high level of activity (IC50 = 0.605 µM) of 2,2':6',2''-terpyridine-metal complexes on lung, breast, pancreatic, and glioblastoma multiforme cancer lines and their selectivity (SI > 41.32) on human normal fibroblasts were confirmed and presented in this paper. The mechanism of action of these compounds is associated with the generation of reactive oxygen species, which affects several cellular pathways and signals. The results demonstrate that 2,2':6',2''-terpyridine-metal complexes affect cell cycle inhibition in the G0/G1 phase as well as the activation of apoptosis and autophagy cell death. These results were confirmed in several independent studies, including experiments measuring the fluorescence levels of reactive oxygen species, flow cytometry, and gene and protein analysis.

The NRF-2/HO-1 Signaling Pathway: A Promising Therapeutic Target for Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a progressive liver disorder with a rising prevalence. It begins with lipid accumulation in hepatocytes and gradually progresses to Metabolic-associated steatohepatitis (MASH), fibrosis, cirrhosis, and potentially hepatocellular carcinoma (HCC). The pathophysiology of MASLD is complex and involves multiple factors, with oxidative stress playing a crucial role. Oxidative stress drives the progression of MASLD by causing cellular damage, inflammatory responses, and fibrosis, making it a key pathogenic mechanism. The Nuclear Factor Erythroid 2-Related Factor 2 / Heme Oxygenase-1 (Nrf2/HO-1) signaling axis provides robust multi-organ protection against a spectrum of endogenous and exogenous insults, particularly oxidative stress. It plays a pivotal role in mediating antioxidant, anti-inflammatory, and anti-apoptotic responses. Many studies indicate that activating the Nrf2/HO-1 signaling pathway can significantly mitigate the progression of MASLD. This article examines the role of the Nrf2/HO-1 signaling pathway in MASLD and highlights natural compounds that protect against MASLD by targeting Nrf2/HO-1 activation. The findings indicate that the Nrf2/HO-1 signaling pathway holds great promise as a therapeutic target for MASLD.

Exploring the effects of pemetrexed on drug resistance mechanisms in human lung adenocarcinoma and its association with PGRMC1

According to the 2022 cancer statistics of the World Health Organization, lung cancer ranks among the top ten causes of death, with lung adenocarcinoma being the most prevalent type. Despite significant advancements in lung cancer therapeutics, many clinical limitations remain, primarily due to the development of drug resistance. The present study investigated the effects of pemetrexed on the drug resistance mechanisms in human lung adenocarcinoma and its association with progesterone receptor membrane component 1 (PGRMC1) expression. Given that KRAS-mutant lung adenocarcinoma cell lines (e.g., A549) exhibit a high folate synthesis activity, pemetrexed, which is structurally similar to folate, was selected as the therapeutic drug. The present study used a lung adenocarcinoma cell line (A549) and established a drug-resistant lung adenocarcinoma cell line (A549/PEM). The findings demonstrated that PGRMC1 expression was elevated in the A549/PEM cells. It has been hypothesized that PGRMC1 regulates iron absorption through heme binding, resulting in a preference for iron-related cell death pathways (ferroptosis). Our findings indicate that drug-resistant lung adenocarcinoma cells with high PGRMC1 levels exhibit elevated antioxidant activity on the cell membrane and increased reliance on iron-dependent cell death pathways. This suggests a correlation between PGRMC1 and pemetrexed-induced iron-dependent cell death. Our study contributes to the development of more effective therapeutic strategies to improve the prognosis of patients with lung adenocarcinoma, particularly those facing drug resistance challenges.

Heme oxygenase-1: potential therapeutic targets for periodontitis

Periodontitis is one of the most prevalent inflammatory disease worldwide, which affects 11% of the global population and is a major cause of tooth loss. Recently, oxidative stress (OS) has been found to be the pivital pathophysiological mechanism of periodontitis, and overactivated OS will lead to inflammation, apoptosis, pyroptosis and alveolar bone resorption. Interestingly, heme oxygenase-1 (HO-1), a rate-limiting enzyme in heme degradation, can exert antioxidant activites through its products-carbon monoxide (CO), Fe2+, biliverdin and bilirubin in the inflammatory microenvironment, thus exhibiting anti-inflammatory, anti-apoptotic, anti-pyroptosis and bone homeostasis-regulating properties. In this review, particular focus is given to the role of HO-1 in periodontitis, including the spatial-temporal expression in periodental tissues and pathophysiological mechanisms of HO-1 in periodontitis, as well as the current therapeutic applications of HO-1 targeted drugs for periodontitis. This review aims to elucidate the potential applications of various HO-1 targeted drug therapy in the management of periodontitis, investigate the influence of diverse functional groups on HO-1 and periodontitis, and pave the way for the development of a new generation of therapeutics that will benefit patients suffering from periodontitis.

Crosstalk between ferroptosis and macrophages: potential value for targeted treatment in diseases

Ferroptosis is a newly identified form of programmed cell death that is connected to iron-dependent lipid peroxidization. It involves a variety of physiological processes involving iron metabolism, lipid metabolism, oxidative stress, and biosynthesis of nicotinamide adenine dinucleotide phosphate, glutathione, and coenzyme Q10. So far, it has been discovered to contribute to the pathological process of many diseases, such as myocardial infarction, acute kidney injury, atherosclerosis, and so on. Macrophages are innate immune system cells that regulate metabolism, phagocytize pathogens and dead cells, mediate inflammatory reactions, promote tissue repair, etc. Emerging evidence shows strong associations between macrophages and ferroptosis, which can provide us with a deeper comprehension of the pathological process of diseases and new targets for the treatments. In this review, we summarized the crosstalk between macrophages and ferroptosis and anatomized the application of this association in disease treatments, both non-neoplastic and neoplastic diseases. In addition, we have also addressed problems that remain to be investigated, in the hope of inspiring novel therapeutic strategies for diseases.

Carbon monoxide and mitochondria: Cell energy and fate control

Carbon monoxide (CO) is a ubiquitously produced endogenous gas in mammalian cells and is involved in stress response being considered as a cytoprotective and homeostatic factor. In the present review, the underlying mechanisms of CO are discussed, in particular CO's impact on cellular metabolism affecting cell fate and function. One of the principal signaling molecules of CO is reactive oxygen species (ROS), particularly hydrogen peroxide, which is mainly generated at the mitochondrial level. Likewise, CO acts on mitochondria modulating oxidative phosphorylation and mitochondria quality control, namely mitochondrial biogenesis (mitobiogenesis) and mitophagy. Other metabolic pathways are also involved in CO's mode of action such as glycolysis and pentose phosphate pathway. The review ends with some new perspectives on CO Biology research. Carboxyhemoglobin (COHb) formation can also be implicated in the CO mode of action, as well as its potential biological role. Finally, other organelles such as peroxisomes hold the potential to be targeted and modulated by CO.

Potential skin anti-aging effects of main phenolic compounds, tremulacin and tremuloidin from Salix chaenomeloides leaves on TNF-α-stimulated human dermal fibroblasts

The genus Salix spp. has long been recognized as a healing herb for its use in treating fever, inflammation, and pain relief, as well as a food source for its nutritional value. In this study, we aimed to explore the potential bioactive natural products in the leaves of Salix chaenomeloides, commonly known as Korean pussy willow, for their protective effects against skin damage, including aging. Utilizing LC/MS-guided chemical analysis of the ethanol extract of S. chaenomeloides leaves, with a focus on major compounds, we successfully isolated two main phenolic compounds, tremulacin (1) and tremuloidin (2). Subsequently, we investigated the protective effects of tremulacin (1) and tremuloidin (2) in TNF-α-stimulated human dermal fibroblasts (HDFs). The results revealed that both tremulacin (1) and tremuloidin (2) inhibited TNF-α-stimulation-induced ROS, suppressed matrix metalloproteinase-1 (MMP-1) expression, and enhanced collagen secretion. This implies that both tremulacin (1) and tremuloidin (2) hold promise as preventive agents against photoaging-induced skin aging. Furthermore, we assessed the activity of mitogen-activated protein kinases (MAPKs), cyclooxygenase-2 (COX-2), and heme oxygenase 1 (HO-1) to elucidate the mechanism of photoaging inhibition by tremuloidin (2), which exhibited superior efficacy. We found that tremuloidin (2) inhibited ERK and p38 phosphorylation and notably suppressed COX-2 expression while significantly upregulating HO-1 expression. These findings suggest potent anti-inflammatory and antioxidant properties of tremuloidin (2), positioning it as a potential candidate for combating photoaging-induced skin aging.

Role of gasotransmitters in necroptosis

Gasotransmitters are endogenous gaseous signaling molecules that can freely pass through cell membranes and transmit signals between cells, playing multiple roles in cell signal transduction. Due to extensive and ongoing research in this field, we have successfully identified many gasotransmitters so far, among which nitric oxide, carbon monoxide, and hydrogen sulfide are best studied. Gasotransmitters are implicated in various diseases related to necroptosis, such as cardiovascular diseases, inflammation, ischemia-reperfusion, infectious diseases, and neurological diseases. However, the mechanisms of their effects on necroptosis are not fully understood. This review focuses on endogenous gasotransmitter synthesis and metabolism and discusses their roles in necroptosis, aiming to offer new insights for the therapeutic approaches to necroptosis-associated diseases.

Early Weaning Inhibits Intestinal Stem Cell Expansion to Disrupt the Intestinal Integrity of Duroc Piglets via Regulating the Keap1/Nrf2 Signaling

There are different stress resistance among different breeds of pigs. Changes in intestinal stem cells (ISCs) are still unclear among various breeds of piglets after early weaning. In the current study, Taoyuan Black and Duroc piglets were slaughtered at 21 days of age (early weaning day) and 24 days of age (3 days after early weaning) for 10 piglets in each group. The results showed that the rate of ISC-driven epithelial renewal in local Taoyuan Black pigs hardly changed after weaning for 3 days. However, weaning stress significantly reduced the weight of the duodenum and jejunum in Duroc piglets. Meanwhile, the jejunal villus height, tight junction-related proteins (ZO-1, Occludin, and Claudin1), as well as the trans-epithelial electrical resistance (TEER) values, were down-regulated after weaning for 3 days in Duroc piglets. Moreover, compared with Unweaned Duroc piglets, the numbers of Olfm4+ ISC cells, PCNA+ mitotic cells, SOX9+ secretory progenitor cells, and Villin+ absorptive cells in the jejunum were reduced significantly 3 days after weaning. And ex vivo jejunal crypt-derived organoids exhibited growth disadvantages in weaned Duroc piglets. Notably, the Keap1/Nrf2 signaling activities and the expression of HO-1 were significantly depressed in weaned Duroc piglets compared to Unweaned Duroc piglets. Thus, we can conclude that ISCs of Duroc piglets were more sensitive to weaning stress injury than Taoyuan Black piglets, and Keap1/Nrf2 signaling is involved in this process.

Pretreatment with aqueous Moringa oleifera Lam. leaf extract prevents cadmium-induced hepatotoxicity by improving cellular antioxidant machinery and reducing cadmium accumulation

Cadmium (Cd) is a highly harmful pollutant that poses a serious threat to human health. The liver is the primary organ for Cd accumulation, and Cd-induced hepatotoxicity has been shown to be strongly correlated with an oxidative imbalance in hepatocytes. Our previous studies in the eukaryotic model organism Saccharomyces cerevisiae revealed that not only co-treatment but also pretreatment with aqueous Moringa oleifera Lam. leaf extract (AMOLE) effectively mitigated Cd toxicity by reducing intracellular Cd accumulation and Cd-mediated oxidative stress. In this study, we therefore investigated the preventive effect of AMOLE against Cd toxicity in human HepG2 hepatocytes. The results showed that, similar to the case of the yeast model, pretreatment with AMOLE prior to Cd exposure also significantly inhibited Cd-induced oxidative stress in HepG2 cells. Untargeted LC-MS/MS-based metabolomic analysis of AMOLE revealed that its major phytochemical constituents were organic acids, particularly phenolic acids and carboxylic acids. Additionally, DPPH-HPTLC fingerprints suggested that quercetin and other flavonoids possibly contribute to the antioxidant activities of AMOLE. Based on our findings, it appears that pretreatment with AMOLE prevented Cd-induced hepatotoxicity via three possible mechanisms: i) direct elimination of free radicals by AMOLE antioxidant compounds; ii) upregulation of antioxidant defensive machinery (GPx1, and HO-1) via Nrf2 signaling cascade to improve cellular antioxidant capacity; and iii) reduction of intracellular Cd accumulation, probably by suppressing Cd uptake. These data strongly suggest the high potential of AMOLE for clinical utility in the prevention of Cd toxicity.

Turn-on fluorescence detection of carbon monoxide in plant tissues based on Cu2+ modulated polydihydroxyphenylalanine nanosensors

As an important signaling molecule, carbon monoxide (CO) plays an important role in plant growth and development including affecting stomatal movement, stress response and root development. Thus, it is necessary to develop fluorescent probes that can be used to detect CO in live plant tissues and further enable a deep-understanding of its biological function, mechanism and metabolism. In this paper, a novel and sensitive fluorescent probe based on Cu2+ modulated polydihydroxyphenylalanine nanoparticles (PDOAs) has been developed for the detection of CO. The fluorescence of PDOAs can be effectively quenched by Cu2+ through the multi-coordination interaction. In the presence of CO, Cu2+ can be effectively reduced to Cu+, which resulted in the release of free PDOAs and the Cu2+-quenched bright green fluorescence was restored obviously. Through this ingenious strategy, the abiotic CO can be accurately detected and identified with high selectivity, rapid response time within 5 min and an ultralow detection limit of 72.4 nM. Due to the admirable biocompatibility, the nano-material based probe has been successfully applied for in vivo imaging CO in the root tip and leave tissues of lettuce. To the best of our knowledge, this is the first example of a fluorescent probe-based methodology for the sensitive tracking of CO in plant tissues.

Activation of Nuclear Factor Erythroid 2-Related Factor-2 by Oxylipin from Mangifera indica Leaves

Mangifera indica L., a member of the Anacardiaceae family, is widely cultivated across the globe. The leaves of M. indica are renowned for their medicinal properties, attributed to the abundance of bioactive compounds. This study investigated the effects of mango leaf extract on oxidative stress in HeLa cells. Notably, the n-hexane fraction (MLHx) significantly enhanced antioxidant response element (ARE)-luciferase activity at a concentration of 100 µg/mL, surpassing other fractions. MLHx also promoted the expression of HO-1 mRNA by increasing nuclear NRF2 levels. The molecular mechanism of MLHx involves increased phosphorylation of ERK1/2 and stabilization of NRF2. Bioactivity-guided isolation resulted in the identification of six oxylipins: 13(R)-hydroxy-octadeca-(9Z,11E,15Z)-trienoic acid (C-1), 9(R)-hydroxy-octadeca-(10E,12Z,15Z)-trienoic acid (C-2), 13(R)-hydroxy-(9Z,11E)-octadecadienoic acid (C-3), 9(R)-hydroxy-(10E,12Z)-octadecadienoic acid (C-4), 9-oxo-(10E,12E)-octadecadienoic acid (C-5), and 9-oxo-(10E,12Z)-octadecadienoic acid (C-6). These structures were elucidated using comprehensive spectroscopic techniques, including MS and 1H NMR. Additionally, compounds C-7 (9-oxo-(10E,12Z,15Z)-octadecatrienoic acid) and 8 (13-oxo-(9E,11E)-octadecadienoic acid) were characterized by LC-MS/MS mass fragmentation. This study reports the isolation of compounds 1-6 from M. indica for the first time. When tested for their effect on NRF2 activity in HeLa cells, compounds 3, 5, and 6 showed strong stimulation of ARE-luciferase activity in a dose-dependent manner.

Hydrogen sulfide and its potential as a possible therapeutic agent in male reproduction

Hydrogen sulfide (H2S) is an endogenously produced signaling molecule that belongs to the group of gasotransmitters along with nitric oxide (NO) and carbon monoxide (CO). H2S plays a pivotal role in male reproductive processes. It is produced in various tissues and cells of the male reproductive system, including testicular tissue, Leydig and Sertoli cells, epididymis, seminal plasma, prostate, penile tissues, and sperm cells. This review aims to summarize the knowledge about the presence and effects of H2S in male reproductive tissues and outline possible therapeutic strategies in pathological conditions related to male fertility, e. g. spermatogenetic disorders and erectile dysfunction (ED). For instance, H2S supports spermatogenesis by maintaining the integrity of the blood-testicular barrier (BTB), stimulating testosterone production, and providing cytoprotective effects. In spermatozoa, H2S modulates sperm motility, promotes sperm maturation, capacitation, and acrosome reaction, and has significant cytoprotective effects. Given its vasorelaxant effects, it supports the erection of penile tissue. These findings suggest the importance and therapeutic potential of H2S in male reproduction, paving the way for further research and potential clinical applications.

Direct Ingestion of Oxidized Red Blood Cells (Efferocytosis) by Hepatocytes

Purpose

Both hepatic iron accumulation and hemolysis have been identified as independent prognostic factor in alcohol-related liver disease (ALD); however, the mechanisms still remain poorly understood. We here demonstrate that hepatocytes are able to directly ingest aged and ethanol-primed red blood cells (RBCs), a process termed efferocytosis.

Methods

Efferocytosis of RBCs was directly studied in vitro and observed by live microscopy for real-time visualization. RBCs pretreated with either CuSO4 or ethanol following co-incubation with Huh7 cells and murine primary hepatocytes. Heme oxygenase-1 (HO-1) and other targets were measured by q-PCR.

Results

As shown by live microscopy, oxidized RBCs, but not intact RBCs, are rapidly ingested by both Huh7 cells and murine primary hepatocytes within 10 minutes. In some cases, more than 10 RBCs were seen within hepatocytes, surrounding the nucleus. RBC efferocytosis also rapidly induces HO1, its upstream regulator Nuclear factor erythroid 2-related factor 2 (Nrf2) and ferritin, indicating efficient heme degradation. Preliminary data further suggest that hepatocyte efferocytosis of oxidized RBCs is, at least in part, mediated by scavenging receptors such as ASGPR1. Of note, pretreatment of RBCs with ethanol but also heme and bilirubin also initiated efferocytosis. In a cohort of heavy human drinkers, a significant correlation of hepatic ASGPR1 with the heme degradation pathway was observed.

Conclusion

We here demonstrate that hepatocytes can directly ingest and degrade oxidized RBCs through efferocytosis, a process that can be also triggered by ethanol, heme and bilirubin. Our findings are highly suggestive for a novel mechanism of hepatic iron overload in ALD patients.

The role of nitric oxide synthase/ nitric oxide in infection-related cancers: Beyond antimicrobial activity

As a free radical and endogenous effector molecule, mammalian endogenous nitric oxide (NO) is mainly derived from nitric oxide synthase (NOS) via L-arginine. NO participates in normal physiological reactions and provides immune responses to prevent the invasion of foreign bacteria. However, NO also has complex and contradictory biological effects. Abnormal NO signaling is involved in the progression of many diseases, such as cancer. In the past decades, cancer research has been closely linked with NOS/ NO, and many tumors with poor prognosis are associated with high expression of NOS. In this review, we give a overview of the biological effects of NOS/ NO. Then we focus on the oncogenic role of iNOS/ NO in HPV, HBV, EBV and H. pylori related tumors. In fact, there is growing evidence that iNOS could be used as a potential therapeutic target in cancer therapy. We emphasize that the pro-tumor effect of NOS/ NO is greater than the anti-tumor effect.

NCI677397 targeting USP24-mediated induction of lipid peroxidation induces ferroptosis in drug-resistant cancer cells

Cancer represents a profound challenge to healthcare systems and individuals worldwide. The development of multiple drug resistance is a major problem in cancer therapy and can result in progression of the disease. In our previous studies, we developed small-molecule inhibitors targeting ubiquitin-specific peptidase 24 (USP24) to combat drug-resistant lung cancer. Recently, we found that the USP24 inhibitor NCI677397 induced ferroptosis, a type of programmed cell death, in drug-resistant cancer cells by increasing lipid reactive oxygen species (ROS) levels. In the present study, we investigated the molecular mechanisms and found that the targeting of USP24 by NCI677397 increased gene expression of most lipogenesis-related genes, such as acyl-CoA synthetase long-chain family member 4 (ACSL4), and activated autophagy. In addition, the activity of several antioxidant enzymes, such as glutathione peroxidase 4 (GPX4) and dihydrofolate reductase (DHFR), was inhibited by NCI677397 treatment via an increase in protein degradation, thereby inducing lipid ROS production and lipid peroxidation. In summary, we demonstrated that NCI677397 induced a marked increase in lipid ROS levels, subsequently causing lipid peroxidation and leading to the ferroptotic death of drug-resistant cancer cells. Our study provides new insights into the clinical use of USP24 inhibitors as ferroptosis inducers (FINs) to block drug resistance during chemotherapy.

Helicobacter pylori triggers inflammation and oncogenic transformation by perturbing the immune microenvironment

The immune microenvironment plays a critical regulatory role in the pathogenesis of Helicobacter pylori (H. pylori). Understanding the mechanisms that drive the transition from chronic inflammation to cancer may provide new insights for early detection of gastric cancer. Although chronic inflammation is frequent in precancerous gastric conditions, the monitoring function of the inflammatory microenvironment in the progression from H. pylori-induced chronic inflammation to gastric cancer remains unclear. This literature review summarizes significant findings on how H. pylori triggers inflammatory responses and facilitates cancer development through the immune microenvironment. Furthermore, the implications for future research and clinical applications are also addressed. The review is divided into four main sections: inflammatory response and immune evasion mechanisms induced by H. pylori, immune dysregulation associated with gastric cancer, therapeutic implications, and future perspectives on H. pylori-induced gastric carcinogenesis with a focus on the immune microenvironment.

Heme Oxygenase-1 and Prostate Cancer: Function, Regulation, and Implication in Cancer Therapy

Prostate cancer (PC) is a significant cause of mortality in men worldwide, hence the need for a comprehensive understanding of the molecular mechanisms underlying its progression and resistance to treatment. Heme oxygenase-1 (HO-1), an inducible enzyme involved in heme catabolism, has emerged as a critical player in cancer biology, including PC. This review explores the multifaceted role of HO-1 in PC, encompassing its function, regulation, and implications in cancer therapy. HO-1 influences cell proliferation, anti-apoptotic pathways, angiogenesis, and the tumor microenvironment, thereby influencing tumor growth and metastasis. HO-1 has also been associated with therapy resistance, affecting response to standard treatments. Moreover, HO-1 plays a significant role in immune modulation, affecting the tumor immune microenvironment and potentially influencing therapy outcomes. Understanding the intricate balance of HO-1 in PC is vital for developing effective therapeutic strategies. This review further explores the potential of targeting HO-1 as a therapeutic approach, highlighting challenges and opportunities. Additionally, clinical implications are discussed, focusing on the prognostic value of HO-1 expression and the development of novel combined therapies to augment PC sensitivity to standard treatment strategies. Ultimately, unraveling the complexities of HO-1 in PC biology will provide critical insights into personalized treatment approaches for PC patients.

Mechanism of Action and Therapeutic Implications of Nrf2/HO-1 in Inflammatory Bowel Disease

Oxidative stress (OS) is a key factor in the generation of various pathophysiological conditions. Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) is a major transcriptional regulator of antioxidant reactions. Heme oxygenase-1 (HO-1), a gene regulated by Nrf2, is one of the most critical cytoprotective molecules. In recent years, Nrf2/HO-1 has received widespread attention as a major regulatory pathway for intracellular defense against oxidative stress. It is considered as a potential target for the treatment of inflammatory bowel disease (IBD). This review highlights the mechanism of action and therapeutic significance of Nrf2/HO-1 in IBD and IBD complications (intestinal fibrosis and colorectal cancer (CRC)), as well as the potential of phytochemicals targeting Nrf2/HO-1 in the treatment of IBD. The results suggest that the therapeutic effects of Nrf2/HO-1 on IBD mainly involve the following aspects: (1) Controlling of oxidative stress to reduce intestinal inflammation and injury; (2) Regulation of intestinal flora to repair the intestinal mucosal barrier; and (3) Prevention of ferroptosis in intestinal epithelial cells. However, due to the complex role of Nrf2/HO-1, a more nuanced understanding of the exact mechanisms involved in Nrf2/HO-1 is the way forward for the treatment of IBD in the future.

Synthesis and Characterization of Guanidinylated CO-Releasing Micelles Based on Biodegradable Polycarbonate

As one of the gaseous signals in living cells, carbon monoxide (CO) not only participates in many biological activities but also serves as a therapeutic agent for the treatment of diseases. However, the limited applicability of CO in gas therapy emerges from the inconvenience of direct administration of CO. Here we reported the construction of guanidinylated CO-releasing micelles, which are composed of poly(trimethylene carbonate) (PTMC)-based CO donors. The in vitro studies demonstrated that micelles in the presence of light irradiation can induce cancer death, whereas no obvious toxicity to normal cells was observed. Moreover, the functionalization of guanidine groups imparts improved cellular uptake efficiency to micelles owing to the specific interactions with the surface of cells, which synergistically increase the anticancer capacity of the system. The guanidine-functionalized CO-releasing micelles provide a new strategy for the construction of CO-releasing nanocarriers, which are expected to find applications in gas therapeutics.

Anti‑inflammatory effects of methanol extract from Peperomia dindygulensis Miq. mediated by HO‑1 in LPS‑induced RAW 264.7 cells

Inflammation serves as a multifaceted defense mechanism activated by pathogens, cellular damage and irritants, aiming to eliminate primary causes of injury and promote tissue repair. Peperomia dindygulensis Miq. (P. dindygulensis), prevalent in Vietnam and southern China, has a history of traditional use for treating cough, fever and asthma. Previous studies on its phytochemicals have shown their potential as anti-inflammatory agents, yet underlying mechanisms remain to be elucidated. The present study investigated the regulatory effects of P. dindygulensis on the anti-inflammatory pathways. The methanol extracts of P. dindygulensis (PDME) were found to inhibit nitric oxide (NO) production and induce heme oxygenase-1 (HO-1) expression in murine macrophages. While MAPKs inhibitors, such as SP600125, SB203580 and U0126 did not regulate HO-1 expression, the treatment of cycloheximide, a translation inhibitor, reduced HO-1. Furthermore, PDME inhibited lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and TNF-α expression at both the mRNA and protein levels. The activity of NOS and the expression of TNF-α, iNOS and COX-2 decreased in LPS-stimulated Raw 264.7 cells treated with PDME and this effect was regulated by inhibition of HO-1 activity. These findings suggested that PDME functions as an HO-1 inducer and serves as an effective natural anti-inflammatory agent in LPS-induced inflammation.

Inhalation of hydrogen gas protects against mitomycin-induced pulmonary veno-occlusive disease

BACKGROUND

As a subtype of pulmonary hypertension (PH), pulmonary veno-occlusive disease (PVOD) is devastating and life-threatening disease without effective therapy. Hydrogen has been reported to exhibits antioxidant and anti-inflammatory effects in a rat model induced by monocrotaline of PH. In this study, we investigated the effects of inhaled hydrogen gas on the prevention and treatment of PVOD induced by mitomycin C (MMC) in rats.

METHODS

PVOD was induced in female Sprague-Dawley rats through intraperitoneal injection of MMC at a concentration of 3 mg·kg- 1·wk- 1 for 2 weeks. Inhalation of hydrogen gas (H2) was administered through a designed rat cage concurrently or two weeks after MMC administration. The severity of PVOD was assessed by using hemodynamic measurements and histological analysis. The expression levels of general control nonderepressible 2 (GCN2), nuclear factor erythroid 2-related factor-2 (Nrf2), heme oxygenase-1 (HO-1) and endothelial-to-mesenchymal transition (EndoMT) related proteins in lung tissue were measured. Levels of lipid peroxidation pro-inflammatory cytokines in serum were determined.

RESULTS

Inhaled H2 improved hemodynamics and right heart function, reversed right ventricular hypertrophy, and prevented pulmonary vessel reconstitution in both prevention and treatment approaches. It decreased malondialdehyde (MDA) levels in the serum and the expression of NADPH oxidase 1 (NOX-1) in lung tissue. It regulated Nrf2/HO-1 signaling pathway and anti-inflammatory factor GCN2 in lung tissue, accompanied by a decrease in macrophages and pro-inflammatory cytokines. Our data suggested that H2 inhalation effectively countered EndoMT induced by MMC, as evidenced by the detection of endothelial markers (e.g., VE-cadherin and CD31) and mesenchymal markers (e.g., vimentin and fibronectin). Further research revealed that H2 preserved p-Smad3 and induced p-Smad1/5/9.

CONCLUSION

Inhalation of H2 effectively inhibits the pathogenesis of PVOD induced by MMC in rats. This inhibitory effect may be attributed to the antioxidant and anti-inflammatory properties of H2.

Carbon monoxide-induced autophagy enhances human mesenchymal stromal cell function via paracrine actions in murine polymicrobial sepsis

Sepsis is a life-threatening process due to organ dysfunction resulting from severe infections. Mesenchymal stromal cells (MSCs) are being investigated as therapy for sepsis, along with conditioning regimens to improve their function. Carbon monoxide (CO) gas, which is cytoprotective at low doses, induces autophagy and is a mediator of inflammation. We evaluated CO-induced autophagy in human MSCs (hMSCs), and its impact on cell function in murine cecal ligation and puncture. Conditioning of hMSCs with CO ex vivo resulted in enhanced survival and bacterial clearance in vivo, and neutrophil phagocytosis of bacteria in vitro. Decreased neutrophil infiltration and less parenchymal cell death in organs were associated with increased macrophage efferocytosis of apoptotic neutrophils, promoting resolution of inflammation. These CO effects were lost when the cells were exposed to autophagy inhibition prior to gas exposure. When assessing paracrine actions of CO-induced autophagy, extracellular vesicles (EVs) were predominantly responsible. CO had no effect on EV production, but altered their miRNA cargo. Increased expression of miR-145-3p and miR-193a-3p by CO was blunted with disruption of autophagy, and inhibitors of these miRNAs led to a loss of neutrophil phagocytosis and macrophage efferocytosis. Collectively, CO-induced autophagy enhanced hMSC function during sepsis via paracrine actions of MSC-derived EVs.