Alternative localization of HEME OXYGENASE 1 in plant cells regulates cytosolic heme catabolism.

Heme, an organometallic tetrapyrrole, is widely engaged in oxygen transport, electron delivery, enzymatic reactions, and signal transduction. In plants, it is also involved in photomorphogenesis and photosynthesis. HEME OXYGENASE 1 (HO1) initiates the first committed step in heme catabolism, and it has generally been thought that this reaction takes place in chloroplasts. Here, we show that HO1 in both Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) has two transcription start sites (TSSs), producing long (HO1L) and short (HO1S) transcripts. Their products localize to the chloroplast and the cytosol, respectively. During early development or de-etiolation, the HO1L/HO1S ratio gradually increases. Light perception via phytochromes and cryptochromes elevates the HO1L/HO1S ratio in the whole seedling through the functions of ELONGATED HYPOCOTYL 5 (HY5) and HY5 HOMOLOG (HYH) and through the suppression of DE-ETIOLATED 1 (DET1), CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1), and PHYTOCHROME INTERACTING FACTORs (PIFs). HO1L introduction complements the HO1-deficient mutant; surprisingly, HO1S expression also restores the short hypocotyl phenotype and high pigment content and helps the mutant recover from the genomes uncoupled (gun) phenotype. This indicates the assembly of functional phytochromes within these lines. Furthermore, our findings support the hypothesis that a mobile heme signal is involved in retrograde signaling from the chloroplast. Altogether, our work clarifies the molecular mechanism of HO1 TSS regulation and highlights the presence of a cytosolic bypass for heme catabolism in plant cells.

Heme oxygenase-1 alleviates allergic airway inflammation by suppressing NF-κB-mediated pyroptosis of bronchial epithelial cells.

Allergic asthma development and pathogenesis are influenced by airway epithelial cells in response to allergens. Heme oxygenase-1 (HO-1), an inducible enzyme responsible for the breakdown of heme, has been considered an appealing target for the treatment of chronic inflammatory diseases. Herein, we report that alleviation of allergic airway inflammation by HO-1-mediated suppression of pyroptosis in airway epithelial cells (AECs). Using house dust mite (HDM)-induced asthma models of mice, we found increased gasdermin D (GSDMD) in the airway epithelium. In vivo administration of disulfiram, a specific inhibitor of pore formation by GSDMD, decreased thymic stromal lymphopoietin (TSLP) release, T helper type 2 immune response, alleviated airway inflammation, and reduced airway hyperresponsiveness (AHR). HO-1 induction by hemin administration reversed these phenotypes. In vitro studies revealed that HO-1 restrained GSDMD-mediated pyroptosis and cytokine TSLP release in AECs by binding Nuclear Factor-Kappa B (NF-κB) p65 RHD domain and thus controlling NF-κB-dependent pyroptosis. These data provide new therapeutic indications for purposing HO-1 to counteract inflammation, which contributes to allergic inflammation control.

Redox biomarkers in asymptomatic latent human tuberculosis: a comparison with active disease.

BACKGROUND: The latent TB infection (LTBI) is an asymptomatic infection caused by Mycobacterium tuberculosis (M.bt). Previous studies have shown a host-protective role for Heme oxygenase-1 (HO-1) during Mtb infection and an important involvement of Glutathione peroxidase-4 (Gpx4) in the necrotic pathology of the disease. Furthermore, increasing evidence suggested a crucial role for Glutathione in the granulomatous response to M. tb infection, with altered GSH levels associated to decreased host resistance. The aim of this study was to provide additional tools for discriminating the pathologic TB state and the asymptomatic infection. METHODS: We analyzed the gene expression of HO-1 and Gpx4 enzymes in blood of subjects with LTBI, active TB and healthy controls, and we also measured blood levels of the reduced (GSH) and oxidized (GSSG) forms of glutathione, together with the evaluation of GCL expression, the gene responsible for the GSH de novo synthesis. RESULTS: Our findings highlight a shift of glutathione homeostasis towards a more reducing conditions in LTBI, and a different modulation of GSH-dependent genes and HO-1 expression respect to active TB. CONCLUSION: This study can provide useful tools to understand the redox background that address the infection toward the asymptomatic or active disease.

Deficiency of heme oxygenase 1a causes detrimental effects on cardiac function.

Humans lacking heme oxygenase 1 (HMOX1) display growth retardation, haemolytic anaemia, and vulnerability to stress; however, cardiac function remains unclear. We aimed to explore the cardiac function of zebrafish lacking hmox1a at baseline and in response to stress. We generated zebrafish hmox1a mutants using CRISPR/Cas9 genome editing technology. Deletion of hmox1a increases cardiac output and further induces hypertrophy in adults. Adults lacking hmox1a develop myocardial interstitial fibrosis, restrain cardiomyocyte proliferation and downregulate renal haemoglobin and cardiac antioxidative genes. Larvae lacking hmox1a fail to respond to hypoxia, whereas adults are insensitive to isoproterenol stimulation in the heart, suggesting that hmox1a is necessary for cardiac response to stress. Haplodeficiency of hmox1a stimulates non-mitochondrial respiration and cardiac cell proliferation, increases cardiac output in larvae in response to hypoxia, and deteriorates cardiac function and structure in adults upon isoproterenol treatment. Intriguingly, haplodeficiency of hmox1a upregulates cardiac hmox1a and hmox1b in response to isoproterenol. Collectively, deletion of hmox1a results in cardiac remodelling and abrogates cardiac response to hypoxia and isoproterenol. Haplodeficiency of hmox1a aggravates cardiac response to the stress, which could be associated with the upregulation of hmox1a and hmox1b. Our data suggests that HMOX1 homeostasis is essential for maintaining cardiac function and promoting cardioprotective effects.

Activation of heme oxygenase-1 by laminar shear stress ameliorates high glucose-induced endothelial cell and smooth muscle cell dysfunction.

High glucose (HG)-induced endothelial cell (EC) and smooth muscle cell (SMC) dysfunction is critical in diabetes-associated atherosclerosis. However, the roles of heme oxygenase-1 (HO-1), a stress-response protein, in hemodynamic force-generated shear stress and HG-induced metabolic stress remain unclear. This investigation examined the cellular effects and mechanisms of HO-1 under physiologically high shear stress (HSS) in HG-treated ECs and adjacent SMCs. We found that exposure of human aortic ECs to HSS significantly increased HO-1 expression; however, this upregulation appeared to be independent of adenosine monophosphate-activated protein kinase, a regulator of HO-1. Furthermore, HSS inhibited the expression of HG-induced intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and reactive oxygen species (ROS) production in ECs. In an EC/SMC co-culture, compared with static conditions, subjecting ECs close to SMCs to HSS and HG significantly suppressed SMC proliferation while increasing the expression of physiological contractile phenotype markers, such as α-smooth muscle actin and serum response factor. Moreover, HSS and HG decreased the expression of vimentin, an atherogenic synthetic phenotypic marker, in SMCs. Transfecting ECs with HO-1-specific small interfering (si)RNA reversed HSS inhibition on HG-induced inflammation and ROS production in ECs. Similarly, reversed HSS inhibition on HG-induced proliferation and synthetic phenotype formation were observed in co-cultured SMCs. Our findings provide insights into the mechanisms underlying EC-SMC interplay during HG-induced metabolic stress. Strategies to promote HSS in the vessel wall, such as continuous exercise, or the development of HO-1 analogs and mimics of the HSS effect, could provide an effective approach for preventing and treating diabetes-related atherosclerotic vascular complications.

The heme oxygenase-1 metalloporphyrin inhibitor stannsoporfin enhances the bactericidal activity of a novel regimen for multidrug-resistant tuberculosis in a murine model.

Multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) poses significant challenges to global tuberculosis (TB) control efforts. Host-directed therapies (HDTs) offer a novel approach to TB treatment by enhancing immune-mediated clearance of Mtb. Prior preclinical studies found that the inhibition of heme oxygenase-1 (HO-1), an enzyme involved in heme metabolism, with tin-protoporphyrin IX (SnPP) significantly reduced mouse lung bacillary burden when co-administered with the first-line antitubercular regimen. Here, we evaluated the adjunctive HDT activity of a novel HO-1 inhibitor, stannsoporfin (SnMP), in combination with a novel MDR-TB regimen comprising a next-generation diarylquinoline, TBAJ-876 (S), pretomanid (Pa), and a new oxazolidinone, TBI-223 (O) (collectively, SPaO), in Mtb-infected BALB/c mice. After 4 weeks of treatment, SPaO + SnMP 5mg/kg reduced mean lung bacillary burden by an additional 0.69 log10 (P = 0.01) relative to SPaO alone. As early as 2 weeks post-treatment initiation, SnMP adjunctive therapy differentially altered the expression of pro-inflammatory cytokine genes and CD38, a marker of M1 macrophages. Next, we evaluated the sterilizing potential of SnMP adjunctive therapy in a mouse model of microbiological relapse. After 6 weeks of treatment, SPaO + SnMP 10mg/kg reduced lung bacterial burdens to 0.71 ± 0.23 log10 colony-forming units (CFUs), a 0.78 log-fold greater decrease in lung CFU compared to SpaO alone (P = 0.005). However, adjunctive SnMP did not reduce microbiological relapse rates after 5 or 6 weeks of treatment. SnMP was well tolerated and did not significantly alter gross or histological lung pathology. SnMP is a promising HDT candidate requiring further study in combination with regimens for drug-resistant TB.

Inhibition of heme oxygenase 1 alleviates thoracic aortic aneurysm via restoration of extracellular matrix.

BACKGROUND: Thoracic aortic aneurysm (TAA) is a silent but life-threatening cardiovascular disease. Heme oxygenase 1 (HO-1) plays an important role in the cardiovascular diseases but is poorly understood in TAA. This study aims at investigating the role of HO-1 in TAA. METHODS: Single-cell RNA sequencing, Western blot and histological assay were performed to identify specific cellular expression of HO-1 in both human and ß-aminopropionitrile (BAPN)-induced mice TAA. Zinc protoporphyrin (ZnPP), a pharmacological inhibitor of HO-1, was used to investigate whether inhibition of HO-1 could attenuate BAPN-induced TAA in rodent model. Histological assay, Western blot assay, and mRNA sequencing were further performed to explore the underlying mechanisms. RESULTS: Single-cell transcriptomic analyses of 113,800 thoracic aortic cells identified an increase of HO-1(+) macrophage in aneurysmal thoracic aorta from BAPN-induced TAA mice and TAA patients. Histological assay verified HO-1 overexpression in clinical TAA specimens, which was co-localized with CD68(+) macrophage. HO-1(+) macrophage was closely associated with pro-inflammatory response and immune activation. Inhibition of HO-1 through ZnPP significantly alleviated BAPN-induced TAA in mice and restored extracellular matrix (ECM) in vivo. Further experiments showed that ZnPP treatment suppressed the expression of matrix metalloproteinases (MMPs) in aneurysmal thoracic aortic tissues from BAPN-induced TAA mice, including MMP2 and MMP9. Macrophages from myeloid specific HO-1 knockout mice displayed weakened pro-inflammatory activity and ECM degradation capability. CONCLUSION: HO-1(+) macrophage subgroup is a typical hallmark of TAA. Inhibition of HO-1 through ZnPP alleviates BAPN-induced TAA in mice, which might work through restoration of ECM via suppressing MMP2 and MMP9 expression.

Therapeutic effects of genistein in experimentally induced ulcerative colitis in rats via affecting mitochondrial biogenesis.

Ulcerative colitis (UC) is an inflammatory bowel disease that affects the mucosa of the colon, resulting in severe inflammation and ulcers. Genistein is a polyphenolic isoflavone present in several vegetables, such as soybeans and fava beans. Therefore, we conducted the following study to determine the therapeutic effects of genistein on UC in rats by influencing antioxidant activity and mitochondrial biogenesis and the subsequent effects on the apoptotic pathway. UC was induced in rats by single intracolonic administration of 2 ml of 4% acetic acid. Then, UC rats were treated with 25-mg/kg genistein. Colon samples were obtained to assess the gene and protein expression of nuclear factor erythroid 2-related factor-2 (Nrf2), heme oxygenase-1 (HO-1), peroxisome proliferator-activated receptor-gamma coactivator (PGC-1), mitochondrial transcription factor A (TFAM), B-cell lymphoma 2 (BCL2), BCL2-associated X (BAX), caspase-3, caspase-8, and caspase-9. In addition, colon sections were stained with hematoxylin/eosin to investigate the cell structure. The microimages of UC rats revealed inflammatory cell infiltration, hemorrhage, and the destruction of intestinal glands, and these effects were improved by treatment with genistein. Finally, treatment with genistein significantly increased the expression of PGC-1, TFAM, Nrf2, HO-1, and BCL2 and reduced the expression of BAX, caspase-3, caspase-8, and caspase-9. In conclusion, genistein exerted therapeutic effects against UC in rats. This therapeutic activity involved enhancing antioxidant activity and increasing mitochondrial biogenesis, which reduced cell apoptosis.

The immune function of heme oxygenase-1 (HO-1) from Nile tilapia (Oreochromis niloticus) in response to bacterial infection.

Heme oxygenase-1 (HO-1), an inducible rate-limiting metabolic enzyme, exerts critical immunomodulatory functions by potential anti-oxidant, anti-inflammatory, and anti-apoptotic activities. Although accumulative studies have focused on the immune functions of HO-1 in mammals, the roles in fish are poorly understood, and the reports on involvement in the defensive and immune response are very limited. In this study, On-HO-1 gene from Oreochromis niloticus was successfully cloned and identified, which contained an open reading frame (ORF) of 816 bp and coded for a protein of 271 amino acids. The On-HO-1 protein phylogenetically shared a high homology with HO-1 in other teleost fish (76.10%-98.89 %) and a lowly homology with HO-1 in mammals (38.98%-41.55 %). The expression levels of On-HO-1 were highest in the liver of healthy tilapias and sharply induced by Streptococcus agalactiae or Aeromonas hydrophila. Besides, On-HO-1 overexpression significantly increased non-specific immunological parameters in serum during bacterial infection, including LZM, SOD, CAT, ACP, and AKP. It also exerted anti-inflammatory and anti-apoptotic effects in response to the immune response of the infection with S. agalactiae or A. hydrophila by upregulating anti-inflammatory factors (IL-10, TGF-ß), autophagy factors (ATG6, ATG8) and immune-related pathway factors (P65, P38), and down-regulating pro-inflammatory factors (IL-1ß, IL-6, TNF-α), apoptotic factors (Caspase3, Caspase9), pyroptosis factor (Caspase1), and inflammasome (NLRP3). These results suggested that On-HO-1 involved in immunomodulatory functions and host defense in Nile tilapia.

Evaluation of the anticancer effects exerted by 5-fluorouracil and heme oxygenase-1 inhibitor hybrids in HTC116 colorectal cancer cells.

Colon cancer remains a clinical challenge in industrialised countries. Its treatment with 5-Flurouracil (5-FU) develops many side effects and resistance. Thus, several strategies have been undertaken so far, including the use of drug cocktails and polypharmacology. Heme oxygenase-1 (HO-1) is an emerging molecular target in the treatment of various cancers. We recently demonstrated that a combination of HO-1 inhibitors with 5-FU and the corresponding hybrids SI1/17, SI1/20, and SI1/22, possessed anticancer activity against prostate and lung cancer cells. In this work, we evaluated these hybrids in a model of colon cancer and found that SI1/22 and the respective combo have greater potency than 5-FU. Particularly, compounds inhibit HO-1 activity in cell lysates, increase ROS and the expression of HO-1, SOD, and Nrf2. Moreover, we observed a decrease of pro-caspase and an increase in cleaved PARP-1 and p62, suggesting apoptotic and autophagic cell death and potential application of these drugs as anticancer agents.

Diquat causes mouse testis injury through inducing heme oxygenase-1-mediated ferroptosis in spermatogonia.

Diquat dibromide (DQ) is a globally used herbicide in agriculture, and its overuse poses an important public health issue, including male reproductive toxicity in mammals. However, the effects and molecular mechanisms of DQ on testes are limited. In vivo experiments, mice were intraperitoneally injected with 8 or 10 mg/kg/ day of DQ for 28 days. It has been found that heme oxygenase-1 (HO-1) mediates DQ-induced ferroptosis in mouse spermatogonia, thereby damaging testicular development and spermatogenesis. Histopathologically, we found that DQ exposure caused seminiferous tubule disorders, reduced germ cells, and increased sperm malformation, in mice. Reactive oxygen species (ROS) staining of frozen section and transmission electron microscopy (TEM) displayed DQ promoted ROS generation and mitochondrial morphology alterations in mouse testes, suggesting that DQ treatment induced testicular oxidative stress. Subsequent RNA-sequencing further showed that DQ treatment might trigger ferroptosis pathway, attributed to disturbed glutathione metabolism and iron homeostasis in spermatogonia cells in vitro. Consistently, results of western blotting, measurements of MDA and ferrous iron, and ROS staining confirmed that DQ increased oxidative stress and lipid peroxidation, and accelerated ferrous iron accumulation both in vitro and in vivo. Moreover, inhibition of ferroptosis by deferoxamine (DFO) markedly ameliorated DQ-induced cell death and dysfunction. By RNA-sequencing, we found that the expression of HO-1 was significantly upregulated in DQ-treated spermatogonia, while ZnPP (a specific inhibitor of HO-1) blocked spermatogonia ferroptosis by balancing intracellular iron homeostasis. In mice, administration of the ferroptosis inhibitor ferrostatin-1 effectively restored the increase of HO-1 levels in the spermatogonia, prevented spermatogonia death, and alleviated the spermatogenesis disorders induced by DQ. Overall, these findings suggest that HO-1 mediates DQ-induced spermatogonia ferroptosis in mouse testes, and targeting HO-1 may be an effective protective strategy against male reproductive disorders induced by pesticides in agriculture.

Antioxidant Enzymes in Cancer Cells: Their Role in Photodynamic Therapy Resistance and Potential as Targets for Improved Treatment Outcomes.

Photodynamic therapy (PDT) is a selective tumor treatment that consists of a photosensitive compound-a photosensitizer (PS), oxygen, and visible light. Although each component has no cytotoxic properties, their simultaneous use initiates photodynamic reactions (PDRs) and sequentially generates reactive oxygen species (ROS) and/or free radicals as cytotoxic mediators, leading to PDT-induced cell death. Nevertheless, tumor cells develop various cytoprotective mechanisms against PDT, particularly the adaptive mechanism of antioxidant status. This review integrates an in-depth analysis of the cytoprotective mechanism of detoxifying ROS enzymes that interfere with PDT-induced cell death, including superoxide dismutase (SOD), catalase, glutathione redox cycle, and heme oxygenase-1 (HO-1). Furthermore, this review includes the use of antioxidant enzymes inhibitors as a strategy in order to diminish the antioxidant activities of tumor cells and to improve the effectiveness of PDT. Conclusively, PDT is an effective tumor treatment of which its effectiveness can be improved when combined with a specific antioxidant inhibitor.

Assessing the Impact of Influenza Vaccination Timing on Experimental Arthritis: Effects on Disease Progression and Inflammatory Biomarkers.

Numerous studies have indicated a link between vaccines and the exacerbation of autoimmune diseases including rheumatoid arthritis (RA). However, there is no consensus in clinical practice regarding the optimal timing of immunization. Therefore, this study aimed to investigate the impact of the 3Fluart influenza vaccine on the complete Freund's adjuvant (CFA)-induced chronic arthritis rat model and to identify new biomarkers with clinical utility. CFA was injected into the plantar surface of one hind paw and the root of the tail on day 0, and the tail root injection was repeated on day 1. Flu vaccination was performed on day 1 or 7. Paw volume was measured by plethysmometry, mechanonociceptive threshold by dynamic plantar aesthesiometry, neutrophil myeloperoxidase (MPO) activity, and vascular leakage using in vivo optical imaging throughout the 21-day experiment. Inflammatory markers were determined by Western blot and histopathology. CFA-induced swelling, an increase in MPO activity, plasma extravasation in the tibiotarsal joint. Mechanical hyperalgesia of the hind paw was observed 3 days after the injection, which gradually decreased. Co-administration of the flu vaccine on day 7 but not on day 1 resulted in significantly increased heme oxygenase 1 (HO-1) expression. The influenza vaccination appears to have a limited impact on the progression and severity of the inflammatory response and associated pain. Nevertheless, delayed vaccination could alter the disease activity, as indicated by the findings from assessments of edema and inflammatory biomarkers. HO-1 may serve as a potential marker for the severity of inflammation, particularly in the case of delayed vaccination. However, further investigation is needed to fully understand the regulation and role of HO-1, a task that falls outside the scope of the current study.

[Research progress on the mechanism of action of heme oxygenase-1 regulating ferroptosis in non-alcoholic fatty liver disease].

Non-alcoholic fatty liver disease (NAFLD) has gradually become the most prevalent chronic liver disease in the world, but its pathogenesis has not been fully elucidated. Ferroptosis is a novel type of programmed cell death caused by iron-dependent lipid peroxidation. Heme oxygenase-1 is a recognized antioxidant enzyme and an important regulatory factor in ferroptosis that modulates ferroptosis through various pathways and, in turn, regulates NAFLD. This paper reviews the regulatory mechanism of heme oxygenase-1 on NAFLD in ferroptosis pathway, with a view to clarifying the occurrence and development mechanisms of NAFLD and providing new vision and targets for its prevention and treatment.

[Value of constructing a non-invasive diagnostic model based on serum heme oxygenase-1 and glucose regulatory protein 78 for non-alcoholic fatty liver disease].

Objective: To analyze the clinical application value of serum heme oxygenase (HO)-1expression level in non-alcoholic fatty liver disease (NAFLD) and, based on that, establish a diagnostic model combined with glucose regulatory protein 78 (GRP78) so as to clarify its diagnostic effectiveness and application value. Methods: A total of 210 NAFLD patients diagnosed by abdominal B-ultrasound and liver elastography were included, and at the same time, 170 healthy controls were enrolled. The general clinical data, peripheral blood cell counts, and biochemical indicators of the research subjects were collected. The expression levels of HO-1 and GRP78 were detected using an enzyme-linked immunosorbent assay. Multivariate analysis was used to screen independent risk factors for NAFLD. Visual output was performed through nomogram diagrams, and the diagnostic model was constructed. Receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA) were used to evaluate the diagnostic effectiveness of NAFLD. Measurement data were analyzed using a t-test or Mann-Whitney U rank sum test to detect data differences between groups. Enumeration data were analyzed using the Fisher's exact probability test or the Pearson χ(2) test. Results: Compared with the healthy control group, the white blood cell count, aspartate aminotransferase (AST), alanine aminotransferase, gamma-glutamyl transferase (GTT), fasting blood glucose (Glu), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), serum HO-1, and GRP78 levels were significantly increased in the NAFLD group patients (P < 0.05). Binary logistic analysis results showed that AST, TG, LDL-C, serum HO-1, and GRP78 were independent risk factors for NAFLD (P < 0.05). A nomogram clinical predictive model HGATL was established using HO-1 (H), GRP78 (G) combined with AST (A), TG (T), and LDL-C (L), with the formula P=-21.469+3.621×HO-1+0.116 ×GRP78+0.674×AST+6.250×TG+4.122 ×LDL-C. The results confirmed that the area under the ROC curve of the HGATL model was 0.965 8, with an optimal cutoff value of 81.69, a sensitivity of 87.06%, a specificity of 92.82%, a P < 0.05, and the diagnostic effectiveness significantly higher than that of a single indicator. The calibration curve and DCA both showed that the model had good diagnostic performance. Conclusion: The HGATL model can be used as a novel, non-invasive diagnosis model for NAFLD and has a positive application value in NAFLD diagnosis and therapeutic effect evaluation. Therefore, it should be explored and promoted in clinical applications.

Hispolon induces apoptosis in oral squamous cell carcinoma cells through JNK/HO-1 pathway activation.

Oral squamous cell carcinoma (OSCC) has a high recurrence rate and poor prognosis. Hispolon, a polyphenolic compound with antiviral, antioxidant, and anticancer activities, is a potential chemotherapy agent. However, few studies have investigated the anti-cancer mechanism of hispolon in oral cancer. This present study used the cell viability assay, clonogenic assay, fluorescent nuclear staining, and flow cytometry assay to analyse the apoptosis-inducing effects of hispolon in OSCC cells. After hispolon treatment, the apoptotic initiators, cleaved caspase-3, -8, and - 9, were upregulated, whereas the cellular inhibitor of apoptosis protein-1 (cIAP1) was downregulated. Furthermore, a proteome profile analysis using a human apoptosis array revealed the overexpression of heme oxygenase-1 (HO-1) by hispolon, which was determined to be involved in caspase-dependent apoptosis. Moreover, cotreatment with hispolon and mitogen-activated protein kinase (MAPK) inhibitors revealed that hispolon induces apoptosis in OSCC cells through activation of the c-Jun N-terminal kinase (JNK) pathway and not the extracellular signal-regulated kinase (ERK) or p38 pathway. These findings indicate that hispolon may exert an anticancer effect on oral cancer cells by upregulating HO-1 and inducing caspase-dependent apoptosis by activating the JNK pathway.

Heme oxygenase-1: The roles of both good and evil in neurodegenerative diseases.

Heme oxygenase-1 (HO-1) is the only way for cells to decompose heme. It can cleave heme to produce carbon monoxide (CO), ferrous iron (Fe2+ ), and biliverdin (BV). BV is reduced to bilirubin (BR) by biliverdin reductase(BVR). In previous studies, HO-1 was considered to have protective effects because of its anti-inflammatory, anti-apoptosis, and antiproliferation functions. However, emerging experimental studies have found that the metabolites derived from HO-1 can cause increase iin intracellular oxidative stress, mitochondrial damage, iron death, and autophagy. Because of its particularity, it is very meaningful to understand its exact mechanism. In this review, we summarized the protective and toxic effects of HO-1, its potential mechanism, its role in neurodegenerative diseases and related drug research. This knowledge may be beneficial to the development of new therapies for neurodegenerative diseases and is crucial to the development of new therapeutic strategies and biomarkers.

Pharmacological Significance of Heme Oxygenase 1 in Prostate Cancer.

Heme oxygenase 1 (HO-1) is a detoxifying antioxidant microsomal enzyme that regulates inflammation, apoptosis, cell proliferation, and angiogenesis in prostate cancer (PCa). This makes HO-1 a promising target for therapeutic prevention and treatment due to its anti-inflammatory properties and ability to control redox homeostasis. Clinical evidence highlights the possible correlation between HO-1 expression and PCa growth, aggressiveness, metastasized tumors, resistance to therapy, and poor clinical outcomes. Interestingly, studies have reported anticancer benefits mediated by both HO-1 induction and inhibition in PCa models. Contrasting evidence exists on the role of HO-1 in PCa progression and possible treatment targets. Herein, we provide an overview of available evidence on the clinical significance of HO-1 signaling in PCa. It appears that the beneficial effects of HO-1 induction or inhibition are dependent on whether it is a normal versus malignant cell as well as the intensity (major vs. minor) of the increase in HO-1 enzymatic activity. The current literature evidence indicates that HO-1 has dual effects in PCa. The amount of cellular iron and reactive oxygen species (ROS) can determine the role of HO-1 in PCa. A major increase in ROS enforces HO-1 to a protective role. HO-1 overexpression may provide cryoprotection to normal cells against oxidative stress via suppressing the expression of proinflammatory genes, and thus offer therapeutic prevention. In contrast, a moderate increase in ROS can lead to the perpetrator role of HO-1, which is associated with PCa progression and metastasis. HO-1 inhibition by xenobiotics in DNA-damaged cells tilts the balance to promote apoptosis and inhibit PCa proliferation and metastasis. Overall, the totality of the evidence revealed that HO-1 may play a dual role in the therapeutic prevention and treatment of PCa.

Neuroprotective Effects of Water Extract from Brown Algae Petalonia binghamiae in an Experimental Model of Focal Cerebral Ischemia In Vitro and In Vivo.

Focal cerebral ischemia (fCI) can result in brain injury and sensorimotor deficits. Brown algae are currently garnering scientific attention as potential therapeutic candidates for fCI. This study investigated the therapeutic effects of the hot water extract of Petalonia binghamiae (wPB), a brown alga, in in vitro and in vivo models of fCI. The neuroprotective efficacy of wPB was evaluated in an in vitro excitotoxicity model established using HT-22 cells challenged with glutamate. Afterward, C57/BL6 mice were administered wPB for 7 days (10 or 100 mg/kg, intragastric) and subjected to middle cerebral artery occlusion and reperfusion (MCAO/R) operation, which was used as an in vivo fCI model. wPB co-incubation significantly inhibited cell death, oxidative stress, and apoptosis, as well as stimulated the expression of heme oxygenase-1 (HO-1), an antioxidant enzyme, and the nuclear translocation of its upstream regulator, nuclear factor erythroid 2-related factor 2 (Nrf2) in HT-22 cells challenged with glutamate-induced excitotoxicity. Pretreatment with either dose of wPB significantly attenuated infarction volume, neuronal death, and sensorimotor deficits in an in vivo fCI model. Furthermore, the attenuation of oxidative stress and apoptosis in the ischemic lesion accompanied the wPB-associated protection. This study suggests that wPB can counteract fCI via an antioxidative effect, upregulating the Nrf2/HO-1 pathway.

Andrographolide induced heme oxygenase-1 expression in MSC-like cells isolated from rat bone marrow exposed to environmental stress.

BACKGROUND AND OBJECTIVES: Mesenchymal stem cells (MSC-like cells) are the most important stem cells that are used in transplantation clinically in various applications. The survival rate of MSC-like cells is strongly reduced due to adverse conditions in the microenvironment of transplantation, including environmental stress. Heme oxygenase-1 (HO-1) is a member of the heat shock protein, as well as a stress-induced enzyme, present throughout the body. The present study was conducted to investigate the effect of andrographolide, an active derivative from andrographolide paniculate, on HO-1 expression in mesenchymal stem cells derived from rat bone marrow. MATERIALS AND METHODS: The rat bone marrow-derived mesenchymal stem cells (BMSC-like cells) were extracted and proliferated in several passages. The identity of MSC-like cells was confirmed by morphological observations and differential tests. The flow cytometry method was used to verify the MSC-specific markers. Isolated MSC-like cells were treated with different concentrations of andrographolide and then exposed to environmental stress. Cell viability was assessed using the MTT colorimetric assay. A real-time PCR technique was employed to evaluate the expression level of HO-1 in the treated MSC-like cells. RESULTS: Isolated MSC-like cells demonstrated fibroblast-like morphology. These cells in different culture mediums differentiated into osteocytes and adipocytes and were identified using alizarin red and oil red staining, respectively. As well, MSC-like cells were verified by the detection of CD105 surface antigen and the absence of CD14 and CD45 antigens. The results of the MTT assay showed that the pre-treatment of MSC-like cells with andrographolide concentration independently increased the viability and resistance of these cells to environmental stress caused by hydrogen peroxide and serum deprivation (SD). Real-time PCR findings indicated a significant increase in HO-1 gene expression in the andrographolide-receiving groups (p < 0.01). CONCLUSION: Our results suggest that andrographolide creates a promising strategy for enhancing the quality of cell therapy by increasing the resistance of MSC-like cells to environmental stress and inducing the expression of HO-1.