Ferrostatin-1 Blunts Right Ventricular Hypertrophy and Dysfunction in Pulmonary Arterial Hypertension by Suppressing the HMOX1/GSH Signaling.

Ferroptosis plays a critical role in pulmonary arterial hypertension (PAH)-induced right ventricular (RV) dysfunction, but key genes remain largely unclear. We here identified HMOX1 as an essential ferroptosis-related differentially expressed gene in PAH by bioinformatic analysis using FerrDb, GSE119754, and GSE3675 datasets, respectively. Notably, there were marked increases in HMOX1 and iron levels in RV of monocrotaline-induced PAH rats with reduced TAPSE levels. More importantly, treatment with ferrostatin-1 effectively attenuated RV hypertrophy, remodeling, myocardial fibrosis, and dysfunction in PAH rats. In cultured H9C2 cells and primary neonatal rat cardiomyocytes, pretreatment with ferrostatin-1 and knockdown HMOX1 by siRNA strikingly blunted hypoxia-induced promotion of lipid peroxidation, ferroptosis, and cardiomyocyte injury by potentiating glutathione (GSH) and nitric oxide signaling, respectively. In summary, ferrostatin-1 attenuates RV hypertrophy, fibrosis, and dysfunction in PAH by suppressing the HMOX1/GSH signaling. Targeting HMOX1 ferroptosis signaling functions as a potential therapeutic strategy for patients with PAH.

Propofol Pretreatment Inhibits Liver Damage in Mice with Hepatic Ischemia/Reperfusion Injury and Protects Human Hepatocyte in Hypoxia/Reoxygenation.

BACKGROUND/AIMS: The major complication of liver resection is hepatic ischemia/reperfusion injury. Propofol appears to have organprotective effects. Our study aimed to study the protective role of propofol against hepatic ischemia/reperfusion injury and the potential mechanisms. MATERIALS AND METHODS: Mice and human hepatocytes (LO2) were used to establish 2 models: the ischemia/reperfusion injury model in vivo and the hypoxia/reoxygenation model in vitro, respectively. Alanine and aspartate aminotransferase serum levels were detected to evaluate the extent of hepatic cellular injury. Malondialdehyde, superoxide dismutase, glutathione, and catalase expression levels were measured to evaluate the oxidative damage in mice liver. Lactate dehydrogenase levels were detected for hepatocyte cytotoxicity severity. Nuclear factor, erythroid-like 2 and heme oxygenase 1 expression levels were detected. RESULTS: In the ischemia/reperfusion model, propofol pretreatment significantly reduced the alanine aminotransferase and aspartate aminotransferase expression levels, alleviating the hepatic cellular injury. Propofol also protected the mice liver from oxidative damage. In the hypoxia/reoxygenation model, propofol pretreatment reduced lactate dehydrogenase expression levels, suggesting its protective effects in LO2 cells. Furthermore, propofol increased the nuclear factor, erythroid-like 2 and heme oxygenase 1 expression levels both in vivo and in vitro. CONCLUSION: Propofol acts through the nuclear factor, erythroid-like 2, and heme oxygenase 1 pathway to protect the mice liver against ischemia/reperfusion injury and hepatocytes against hypoxia/reoxygenation injury. Propofol should be used as an effective therapeutic drug for hepatic ischemia/reperfusion injury.

HMOX1 pathway signature predicts clinical benefit from immunotherapy plus tyrosine kinase inhibitor therapy in advanced renal cell carcinoma.

BACKGROUND: Immunotherapy (IO) plus tyrosine kinase inhibitor (TKI) emerged as standard first-line therapy for advanced renal cell carcinoma (RCC). The heme Oxygenase 1 (HMOX1) pathway is involved in tumor development and treatment resistance, which may affect the efficacy of TKI + IO. METHODS: Two cohorts from our center (ZS-MRCC, ZS-HRRCC), one cohort from clinical trial (JAVELIN Renal 101) and the Cancer Genome Atlas (TCGA-KIRC) were enrolled. HMOX1 pathway signatures were determined for each sample by RNA-sequencing and gene set enrichment analysis. Immune infiltration was evaluated by flow cytometry. Response and progression-free survival (PFS) were set as primary endpoints. RESULTS: Patients of low-HMOX1 signature showed higher objective response rate (43.5% vs. 27.3%) in ZS-MRCC cohort and longer PFS in both cohorts (ZS-MRCC cohort, p = 0.019; JAVELIN-101 cohort, p = 0.036). Patients in the high-HMOX1 signature arm also showed greater clinical benefit from TKI + IO, rather than TKI monotherapy (p < 0.001). In high-HMOX1 signature RCC tissues, CD8+ T cells showed a dysfunctional phenotype with decreased GZMB expression (Spearman's ρ = -0.32, p = 0.045). A risk score based on HMOX1 signature was further constructed by random forest approach, involving HMOX1 signature and immunologic features. In patients with a low risk level, TKI + IO combination therapy demonstrated longer PFS than TKI monotherapy (p < 0.001), however in individuals with a high risk score group, these two regimens did not give different advantages. CONCLUSIONS: Our study identified the HMOX1 pathway signature was a potential prognostic factor of progression-free survival for TKI + IO combination therapy in the advanced RCC in different cohort, especially in first-line management of mRCC in the Javelin 101 cohort. Moreover, HMOX1 signature was associated with T-cell function in tumor environment.

Hypoxia-induced oxidative stress promotes therapy resistance via upregulation of heme oxygenase-1 in multiple myeloma.

BACKGROUND: Multiple myeloma (MM) is a hematopoietic malignancy for which proteasome inhibitors have become available in recent years. However, many patients develop resistance to these drugs during treatment. Therefore, it is important to elucidate the mechanisms underlying resistance acquisition by proteasome inhibitors. Side population (SP) cells, which have a high drug efflux capacity and hypoxic responses in the microenvironment have both provided important insights into drug resistance in MM; however, little is known about the characteristics of SP cells in hypoxic microenvironments. METHODS: We performed cDNA microarray analysis for SP and non-SP obtained from RPMI-8226 and KMS-11 cell lines cultured for 48 h in normoxic and hypoxic conditions (1% O2 ). Genes specifically upregulated in hypoxic SP were examined. RESULTS: Our comprehensive gene expression analysis identified HMOX1, BACH2, and DUX4 as protein-coding genes that are specifically highly expressed in SP cells under hypoxic conditions. We have shown that HMOX1/heme oxygenase-1 (HMOX1/HO-1) is induced by hypoxia-inducible reactive oxygen species (ROS) and reduces ROS levels. Furthermore, we found that HMOX1 contributes to hypoxia-induced resistance to proteasome inhibitors in vitro and in vivo. Excessive ROS levels synergistically enhance bortezomib sensitivity. In clinical datasets, HMOX1 had a strong and significantly positive correlation with MAFB but not MAF. Interestingly, hypoxic stimulation increased MAFB/MafB expression in myeloma cells; in addition, the knockdown of MAFB under hypoxic conditions suppressed HMOX1 expression. CONCLUSION: These results suggest that the hypoxia-ROS-HMOX1 axis and hypoxia-induced MafB may be important mechanisms of proteasome inhibitor resistance in hypoxic microenvironments.

Neuroprotective Effect of Azithromycin Following Induction of Optic Nerve Crush in Wild Type and Immunodeficient Mice.

This study evaluated the potential neuroprotective effect of azithromycin (AZ) intraperitoneal injections in male C57Bl/6 (wild type, WT) and female NOD scid gamma (NSG) mice subjected to optic nerve crush (ONC) as a model for optic neuropathy. Histologically, reduced apoptosis and improved retinal ganglion cell (RGC) preservation were noted in the AZ-treated mice as shown by TUNEL staining-in the WT mice more than in the NSG mice. The increased microglial activation following ONC was reduced with the AZ treatment. In the molecular analysis of WT and NSG mice, similar trends were detected regarding apoptosis, as well as stress-related and inflammatory markers examining BCL2-associated X (Bax), heme oxygenase 1 (Ho-1), interleukin 1 beta (Il1ß), superoxide dismutase 1 (Sod1), and nuclear factor-kappa B (Nfkb) levels. In the optic nerve, AZ increased the levels of expression of Sod1 and Nfkb only in the WT mice and decreased them in the NSG mice. In the retinas of the WT and NSG mice, the Bax and Ho-1 levels of expression decreased following the AZ treatment, while the Sod1 and Nfkb expression decreased only in the WT mice, and remained stable near the baseline in the NSG mice. Il1ß remained at the baseline in WT mice while it decreased towards the baseline in AZ-treated NSG mice. The neuroprotective effects demonstrated by the reduced RGC apoptosis in AZ-treated WT mice retinae, and in the optic nerves as stress-related and inflammatory gene expression increase. This did not occur in the immunodeficient NSG mice. AZ modulated the inflammatory reaction and microglial activation. The lack of an effect in NSG mice supports the assumption that AZ acts by immunomodulation, which is known to play a role in ONC damage. These findings have implications for the development and repurposing of drugs to preserve RGCs after acute optic neuropathies.

Delivery of self-replicating messenger RNA into the brain for the treatment of ischemic stroke.

Ischemic stroke is caused by the occlusion of cerebral arteries. In the ischemic stroke, ischemia-reperfusion injury increases the damage in the brain after reperfusion. In the previous study, heme oxygenase-1 (HO1) mRNA was delivered into the ischemic brain, showing that HO1-mRNA had higher therapeutic effect and less side-effect than HO1-plasmid (pHO1). However, mRNA is degraded faster than plasmid DNA reducing the duration of gene expression. In this study, self-replicating mRNA (Rep-mRNA) was developed using a replicon system from Venezuelan Equine Encephalitis virus to compensate this disadvantage of mRNA delivery. Deoxycholic acid-conjugated polyethylenimine (DA-PEI) was used as a carrier of the mRNAs. The Rep-mRNA/DA-PEI complex had a size of around 90 nm and a zeta-potential of 33 mV. In the in vitro transfection assays, gene expression by the HO1-Rep-mRNA/DA-PEI complex persisted at least 14 days, while that by the HO1-mRNA/DA-PEI complex approached basal level at 3 days after transfection. Therapeutic effects of the HO1-Rep-mRNA/DA-PEI complexes were evaluated in the ischemic stroke animal model. The complexes were injected into the brain stereotaxically. HO1 expression by the HO1-Rep-mRNA/DA-PEI complex persisted at least 7 days after injection, but the pHO1/DA-PEI or HO1-mRNA/DA-PEI complex showed basal level of HO1-expression at 7 days after injection. Due to higher and longer expression of HO1, the apoptosis level and infarct size were decreased by the HO1-Rep-mRNA/DA-PEI complexes, compared with the pHO1/DA-PEI and HO1-mRNA/DA-PEI complex. These results suggest that HO1-Rep-mRNA/DA-PEI complex may have a potential as a long-lasting therapeutic system for the treatment of ischemic stroke.

Role of Nrf2 and HO-1 in intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) is a common age-related disease with clinical manifestations of lumbar and leg pain and limited mobility. The pathogenesis of IDD is mainly mediated by the death of intervertebral disc (IVD) cells and the imbalance of extracellular matrix (ECM) synthesis and degradation. Oxidative stress and inflammatory reactions are the important factors causing this pathological change. Therefore, the regulation of reactive oxygen species and production of inflammatory factors may be an effective strategy to delay the progression of IDD. In recent years, nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream regulated protein heme oxygenase-1 (HO-1) have received special attention due to their antioxidant, anti-inflammatory and anti-apoptotic protective effects. Recent studies have elucidated the important role of these two proteins in the treatment of IDD disease. However, Nrf2 and HO-1 have not been systematically reported in IDD-related diseases. Therefore, this review describes the biological characteristics of Nrf2 and HO-1, the relationship between Nrf2- and HO-1-regulated oxidative stress and the inflammatory response and IDD, and the progress in research on some extracts targeting Nrf2 and HO-1 to improve IDD. Understanding the role and mechanism of Nrf2 and HO-1 in IDD may provide novel ideas for the clinical treatment and development of Nrf2- and HO-1-targeted drugs.

Curcumin analog, GO-Y078, induces HO-1 transactivation-mediated apoptotic cell death of oral cancer cells by triggering MAPK pathways and AP-1 DNA-binding activity.

BACKGROUND: GO-Y078, a new synthetic analogue of curcumin (CUR), has higher oral bioavailability and anticancer activity than CUR, but the oncostatic effect of GO-Y078 on oral squamous cell carcinoma (OSCC) is largely unknown. RESEARCH DESIGN AND METHODS: In the present study, we examined the oncostatic properties and possible mechanisms of GO-Y078 on human SCC-9 and HSC-3 OSCC cells. RESULTS: Our results indicated that GO-Y078 showed a cytostatic effect against OSCC cells, and this antiproliferative phenomenon stemmed from a mechanism involving multiple levels of cooperation, including cell-cycle G2/M arrest and apoptosis induction. Mechanistically, GO-Y078 treatment induced caspase-mediated apoptosis via upregulating two apoptosis-modulating proteins, SMAC/DIABLO and heme oxygenase (HO)-1. GO-Y078 transcriptionally induced upregulation of the HO-1 gene by increasing the AP-1 DNA-binding activity, which was initiated by activation of the p38 /JNK1/2 pathways. In the clinic, patients with head and neck cancers expressed lower HO-1 and SMAC/DIABLO levels in primary cancer tissues compared to normal tissues. Clinical datasets also revealed that patients with head and neck cancers expressing high HO-1 had afavorable prognosis. CONCLUSIONS: Our results provide new insights into the role of GO-Y078-induced molecular regulation in suppressing OSCC growth and suggest that GO-Y078 has potential therapeutic applications for OSCC.

Heme Oxygenase-1 targeting exosomes for temozolomide resistant glioblastoma synergistic therapy.

Glioblastoma (GBM) is a highly fatal and recurrent brain cancer without a complete prevailing remedy. Although the synthetic nanotechnology-based approaches exhibit excellent therapeutic potential, the associated cytotoxic effects and organ clearance failure rest major obstacles from bench to clinics. Here, we explored allogeneic bone marrow mesenchymal stem cells isolated exosomes (BMSCExo) decorated with heme oxygenase-1 (HMOX1) specific short peptide (HSSP) as temozolomide (TMZ) and small interfering RNA (siRNA) nanocarrier for TMZ resistant glioblastoma therapy. The BMSCExo had excellent TMZ and siRNA loading ability and could traverse the blood-brain barrier (BBB) by leveraging its intrinsic brain accumulation property. Notably, with HSSP decoration, the TMZ or siRNA encapsulated BMSCExo exhibited excellent TMZ resistant GBM targeting ability both in vitro and in vivo due to the overexpression of HMOX1 in TMZ resistant GBM cells. Further, the HSSP decorated BMSCExo delivered the STAT3 targeted siRNA to the TMZ resistant glioma and restore the TMZ sensitivity, consequently achieved the synergistically drug resistant GBM treatment with TMZ. Our results showed this biomimetic nanoplatform can serve as a flexible, robust and inert system for GBM treatment, especially emphasizing the drug resistant challenge.

Correlation between TXNRD1/HO-1 expression and response to neoadjuvant chemoradiation therapy in patients with esophageal squamous cell carcinoma.

BACKGROUND: Thioredoxin reductase 1 (TXNRD1) and heme oxygenase-1 (HO-1) are both involved in the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and play key roles in antioxidant responses. In patients with esophageal squamous cell carcinoma (ESCC), the correlation between the expression of these two proteins and the therapeutic response to neoadjuvant chemoradiation therapy (NACRT), as well as the difference in their expression after chemoradiotherapy, remains unknown. METHODS: Proteins involved in the Nrf2 pathway were immunolocalized in carcinoma cells in ESCC patients on NACRT with 5-fluorouracil and cisplatin, followed by esophagectomy. The 8-hydroxydeoxyguanosine (8-OHdG) levels were used to quantify reactive oxygen species. The changes in immunoreactivity before and after NACRT (Δ) were assessed. RESULTS: Tumor reduction following NACRT was significantly attenuated in pre-therapeutic biopsy specimens associated with high HO-1 status. TXNRD1Δ, HO-1Δ, and 8-OHdGΔ were significantly different in the ineffective and effective groups. The overall survival was significantly lower in high Nrf2 and TXNRD1 groups. In addition, high TXNRD1 expression was an independent prognostic factor in the multivariate analysis of overall survival. CONCLUSIONS: The study findings indicate that HO-1 status in pre-therapeutic biopsy specimens could predict response to NACRT, and TXNRD1 status could predict overall survival of ESCC patients.

Heme-oxygenase and lipid mediators in obesity and associated cardiometabolic diseases: Therapeutic implications.

Obesity-mediated metabolic syndrome remains the leading cause of death worldwide. Among many potential targets for pharmacological intervention, a promising strategy involves the heme oxygenase (HO) system, specifically its inducible form, HO-1. This review collects and updates much of the current knowledge relevant to pharmacology and clinical medicine concerning HO-1 in metabolic diseases and its effect on lipid metabolism. HO-1 has pleotropic effects that collectively reduce inflammation, while increasing vasodilation and insulin and leptin sensitivity. Recent reports indicate that HO-1 with its antioxidants via the effect of bilirubin increases formation of biologically active lipid metabolites such as epoxyeicosatrienoic acid (EET), omega-3 and other polyunsaturated fatty acids (PUFAs). Similarly, HO-1and bilirubin are potential therapeutic targets in the treatment of fat-induced liver diseases. HO-1-mediated upregulation of EET is capable not only of reversing endothelial dysfunction and hypertension, but also of reversing cardiac remodeling, a hallmark of the metabolic syndrome. This process involves browning of white fat tissue (i.e. formation of healthy adipocytes) and reduced lipotoxicity, which otherwise will be toxic to the heart. More importantly, this review examines the activity of EET in biological systems and a series of pathways that explain its mechanism of action and discusses how these might be exploited for potential therapeutic use. We also discuss the link between cardiac ectopic fat deposition and cardiac function in humans, which is similar to that described in obese mice and is regulated by HO-1-EET-PGC1α signaling, a potent negative regulator of the inflammatory adipokine NOV.

Azilsartan attenuates lipopolysaccharide-induced acute lung injury via the Nrf2/HO-1 signaling pathway.

Acute lung injury (ALI) is a severe complication of sepsis and hemorrhagic shock with high morbidity. In the present study, the protective effect of Azilsartan on lipopolysaccharide (LPS)-induced ALI in mice was investigated to explore the potential therapeutic property of Azilsartan for the treatment of ALI. LPS was used to induce an ALI model in mice. Hematoxylin-eosin (HE) staining sections were then evaluated for the pathological state of lung tissues. Bronchoalveolar lavage fluid (BALF) protein concentration, wet/dry weight ratios of lung tissues, and pulmonary myeloperoxidase (MPO) activity were detected to determine the degree of pulmonary injury. The number of total cells, macrophages, and neutrophils in BALF were counted using a hemocytometer to illustrate the inflammatory cell infiltration. The lung function was monitored using a spirometer. The concentrations of interleukin-1ß (IL-1ß), monocyte chemoattractant protein-1 (MCP-1), and interleukin-8 (IL-8) were determined using enzyme-linked immunosorbent assay (ELISA). Oxidative stress was evaluated by the superoxide dismutase (SOD) activity, glutathione (GSH), and malondialdehyde (MDA) concentrations in the lung tissue. The expressions of nuclear erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were determined using Western blot analysis. Azilsartan therapy alleviated LPS-induced lung tissue damage, increased BALF protein concentration, lung wet to dry weight ratio, MPO activity, and macrophage and neutrophils infiltration. Also, Azilsartan ameliorated the production of inflammatory factors (IL-1ß, MCP-1, and IL-8). Azilsartan ameliorated LPS-impaired lung SOD activity, the GSH concentration, and the MDA concentration. Mechanistically, Azilsartan activated the LPS-impaired Nrf2/HO-1 signaling pathway. Azilsartan therapy attenuates LPS-induced ALI via the Nrf2/HO-1 signaling pathway.

Heme oxygenase-1 modulates brain inflammation and apoptosis in mice with angiostrongyliasis.

The rat nematode lungworm Angiostrongylus cantonensis undergoes obligatory intracerebral migration in its hosts and causes eosinophilic meningitis or meningoencephalitis. Heme oxygenase 1 (HO-1) has several cytoprotective properties such as anti-oxidative, anti-inflammatory, and anti-apoptotic effects. HO-1 in brain tissues was induced in A. cantonensis-infected group and showed positive modulation in cobalt protoporphyrin (CoPP)-treated groups. Assay methods for the therapeutic effect include western blot analysis, enzyme-linked immunosorbent assay, gelatin zymography, blood-brain barrier permeability evaluation and eosinophil count in cerebrospinal fluid. The combination of albendazole (ABZ) and CoPP significantly decreased pro-inflammatory cytokines, tumor necrosis factor-α, interleukin (IL)-1ß, IL-5, and IL-33 but significantly increased anti-inflammatory cytokines IL-10 and transforming growth factor-ß. In addition, worm recovery, matrix metalloproteinase-9, BBB permeability, and eosinophil counts were decreased in the ABZ and CoPP co-treated groups. Induction of HO-1 with CoPP strongly inhibited the protein levels of caspase-3 and increased the induction of annexin-V and B-cell leukemia 2. Thus, co-treatment with ABZ and CoPP prevented A. cantonensis-induced eosinophilic meningoencephalitis and its anti-apoptotic effect by promoting HO-1 signaling prior to BBB dysfunction. HO-1 induction might be a therapeutic modality for eosinophilic meningoencephalitis.

HO-1 mitigates acute kidney injury and subsequent kidney-lung cross-talk.

Ischemia-reperfusion injury (IRI) is a leading cause of acute kidney injury (AKI), which contributes to the development of chronic kidney disease (CKD). IRI-induced AKI releases proinflammatory cytokines (e.g. IL-1ß, TNF-α, IL-6) that induce a systemic inflammatory response, resulting in proinflammatory cells recruitment and remote organ damage. AKI is associated with poor outcomes, particularly when extrarenal complications or distant organ injuries occur. Acute lung injury (ALI) is a major remote organ dysfunction associated with AKI. Hence, kidney-lung cross-talk remains a clinical challenge, especially in critically ill population. The stress-responsive enzyme, heme oxygenase-1 (HO-1) is largely known to protect against renal IRI and may be preventively induced using hemin prior to renal insult. However, the use of hemin-induced HO-1 to prevent AKI-induced ALI remains poorly investigated. Mice received an intraperitoneal injection of hemin or sterile saline 1 day prior to surgery. Twenty-four hours later, mice underwent bilateral renal IRI for 26 min or sham surgery. After 4 or 24 h of reperfusion, mice were sacrificed. Hemin-induced HO-1 improved renal outcomes after IRI (i.e. fewer renal damage, renal inflammation, and oxidative stress). This protective effect was associated with a dampened systemic inflammation (i.e. IL-6 and KC). Subsequently, mitigated lung inflammation was found in hemin-treated mice (i.e. neutrophils influx and lung KC). The present study demonstrates that hemin-induced HO-1 controls the magnitude of renal IRI and the subsequent AKI-induced ALI. Therefore, targeting HO-1 represents a promising approach to prevent the impact of renal IRI on distant organs, such as lung.

The Protective Role of Heme Oxygenase-1 in Atherosclerotic Diseases.

Heme oxygenase-1 (HO-1) is an intracellular enzyme that catalyzes the oxidation of heme to generate ferrous iron, carbon monoxide (CO), and biliverdin, which is subsequently converted to bilirubin. These products have anti-inflammatory, anti-oxidant, anti-apoptotic, and anti-thrombotic properties. Although HO-1 is expressed at low levels in most tissues under basal conditions, it is highly inducible in response to various pathophysiological stresses/stimuli. HO-1 induction is thus thought to be an adaptive defense system that functions to protect cells and tissues against injury in many disease settings. In atherosclerosis, HO-1 may play a protective role against the progression of atherosclerosis, mainly due to the degradation of pro-oxidant heme, the generation of anti-oxidants biliverdin and bilirubin and the production of vasodilator CO. In animal models, a lack of HO-1 was shown to accelerate atherosclerosis, whereas HO-1 induction reduced atherosclerosis. It was also reported that HO-1 induction improved the cardiac function and postinfarction survival in animal models of heart failure or myocardial infarction. Recently, we and others examined blood HO-1 levels in patients with atherosclerotic diseases, e.g., coronary artery disease (CAD) and peripheral artery disease (PAD). Taken together, these findings to date support the notion that HO-1 plays a protective role against the progression of atherosclerotic diseases. This review summarizes the roles of HO-1 in atherosclerosis and focuses on the clinical studies that examined the relationships between HO-1 levels and atherosclerotic diseases.

The Role of Heme Oxygenase 1 in the Protective Effect of Caloric Restriction against Diabetic Cardiomyopathy.

Type 2 diabetes mellitus (DM2) leads to cardiomyopathy characterized by cardiomyocyte hypertrophy, followed by mitochondrial dysfunction and interstitial fibrosis, all of which are exacerbated by angiotensin II (AT). SIRT1 and its transcriptional coactivator target PGC-1α (peroxisome proliferator-activated receptor-γ coactivator), and heme oxygenase-1 (HO-1) modulates mitochondrial biogenesis and antioxidant protection. We have previously shown the beneficial effect of caloric restriction (CR) on diabetic cardiomyopathy through intracellular signaling pathways involving the SIRT1-PGC-1α axis. In the current study, we examined the role of HO-1 in diabetic cardiomyopathy in mice subjected to CR. METHODS: Cardiomyopathy was induced in obese diabetic (db/db) mice by AT infusion. Mice were either fed ad libitum or subjected to CR. In an in vitro study, the reactive oxygen species (ROS) level was determined in cardiomyocytes exposed to different glucose levels (7.5-33 mM). We examined the effects of Sn(tin)-mesoporphyrin (SnMP), which is an inhibitor of HO activity, the HO-1 inducer cobalt protoporphyrin (CoPP), and the SIRT1 inhibitor (EX-527) on diabetic cardiomyopathy. RESULTS: Diabetic mice had low levels of HO-1 and elevated levels of the oxidative marker malondialdehyde (MDA). CR attenuated left ventricular hypertrophy (LVH), increased HO-1 levels, and decreased MDA levels. SnMP abolished the protective effects of CR and caused pronounced LVH and cardiac metabolic dysfunction represented by suppressed levels of adiponectin, SIRT1, PPARγ, PGC-1α, and increased MDA. High glucose (33 mM) increased ROS in cultured cardiomyocytes, while SnMP reduced SIRT1, PGC-1α levels, and HO activity. Similarly, SIRT1 inhibition led to a reduction in PGC-1α and HO-1 levels. CoPP increased HO-1 protein levels and activity, SIRT1, and PGC-1α levels, and decreased ROS production, suggesting a positive feedback between SIRT1 and HO-1. CONCLUSION: These results establish a link between SIRT1, PGC-1α, and HO-1 signaling that leads to the attenuation of ROS production and diabetic cardiomyopathy. CoPP mimicked the beneficial effect of CR, while SnMP increased oxidative stress, aggravating cardiac hypertrophy. The data suggest that increasing HO-1 levels constitutes a novel therapeutic approach to protect the diabetic heart. Brief Summary: CR attenuates cardiomyopathy, and increases HO-1, SIRT activity, and PGC-1α protein levels in diabetic mice. High glucose reduces adiponectin, SIRT1, PGC1-1α, and HO-1 levels in cardiomyocytes, resulting in oxidative stress. The pharmacological activation of HO-1 activity mimics the effect of CR, while SnMP increased oxidative stress and cardiac hypertrophy. These data suggest the critical role of HO-1 in protecting the diabetic heart.

Targeting angiogenesis in Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) represents one of the most devastating types of muscular dystrophies which affect boys already at early childhood. Despite the fact that the primary cause of the disease, namely the lack of functional dystrophin is known already for more than 30 years, DMD still remains an incurable disease. Thus, an enormous effort has been made during recent years to reveal novel mechanisms that could provide therapeutic targets for DMD, especially because glucocorticoids treatment acts mostly symptomatic and exerts many side effects, whereas the effectiveness of genetic approaches aiming at the restoration of functional dystrophin is under the constant debate. Taking into account that dystrophin expression is not restricted to muscle cells, but is present also in, e.g., endothelial cells, alterations in angiogenesis process have been proposed to have a significant impact on DMD progression. Indeed, already before the discovery of dystrophin, several abnormalities in blood vessels structure and function have been revealed, suggesting that targeting angiogenesis could be beneficial in DMD. In this review, we will summarize current knowledge about the angiogenesis status both in animal models of DMD as well as in DMD patients, focusing on different organs as well as age- and sex-dependent effects. Moreover, we will critically discuss some approaches such as modulation of vascular endothelial growth factor or nitric oxide related pathways, to enhance angiogenesis and attenuate the dystrophic phenotype. Additionally, we will suggest the potential role of other mediators, such as heme oxygenase-1 or statins in those processes.

Could Heme Oxygenase-1 Be a New Target for Therapeutic Intervention in Malaria-Associated Acute Lung Injury/Acute Respiratory Distress Syndrome?

Malaria is a serious disease and was responsible for 429,000 deaths in 2015. Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is one of the main clinical complications of severe malaria; it is characterized by a high mortality rate and can even occur after antimalarial treatment when parasitemia is not detected. Rodent models of ALI/ARDS show similar clinical signs as in humans when the rodents are infected with murine Plasmodium. In these models, it was shown that the induction of the enzyme heme oxygenase 1 (HO-1) is protective against severe malaria complications, including cerebral malaria and ALI/ARDS. Increased lung endothelial permeability and upregulation of VEGF and other pro-inflammatory cytokines were found to be associated with malaria-associated ALI/ARDS (MA-ALI/ARDS), and both were reduced after HO-1 induction. Additionally, mice were protected against MA-ALI/ARDS after treatment with carbon monoxide- releasing molecules or with carbon monoxide, which is also released by the HO-1 activity. However, high HO-1 levels in inflammatory cells were associated with the respiratory burst of neutrophils and with an intensification of inflammation during episodes of severe malaria in humans. Here, we review the main aspects of HO-1 in malaria and ALI/ARDS, presenting the dual role of HO-1 and possibilities for therapeutic intervention by modulating this important enzyme.

Transduced PEP-1-Heme Oxygenase-1 Fusion Protein Attenuates Lung Injury in Septic Shock Rats.

Oxidative stress and inflammation have been identified to play a vital role in the pathogenesis of lung injury induced by septic shock. Heme oxygenase-1 (HO-1), an effective antioxidant and anti-inflammatory and antiapoptotic substance, has been used for the treatment of heart, lung, and liver diseases. Thus, we postulated that administration of exogenous HO-1 protein transduced by cell-penetrating peptide PEP-1 has a protective role against septic shock-induced lung injury. Septic shock produced by cecal ligation and puncture caused severe lung damage, manifested in the increase in the lung wet/dry ratio, oxidative stress, inflammation, and apoptosis. However, these changes were reversed by treatment with the PEP-1-HO-1 fusion protein, whereas lung injury in septic shock rats was alleviated. Furthermore, the septic shock upregulated the expression of Toll-like receptor 4 (TLR4) and transcription factor NF-κB, accompanied by the increase of lung injury. Administration of PEP-1-HO-1 fusion protein reversed septic shock-induced lung injury by downregulating the expression of TLR4 and NF-κB. Our study indicates that treatment with HO-1 protein transduced by PEP-1 confers protection against septic shock-induced lung injury by its antioxidant, anti-inflammatory, and antiapoptotic effects.

Effects of heme oxygenase-1 recombinant Lactococcus lactis on the intestinal barrier of hemorrhagic shock rats.

This study aimed to investigate the effects of heme oxygenase-1 recombinant Lactococcus lactis (LL-HO-1) on the intestinal barrier of rats with hemorrhagic shock. One hundred Sprague-Dawley male rats (280-320 g) were randomly divided into healthy control group (N group) and hemorrhagic shock group (H group). Each group was subdivided into HO1t, HO2t, HO3t, PBS and LL groups in which rats were intragastrically injected with LL-HO-1 once, twice and three times, PBS and L. lactis (LL), respectively. The mortality, intestinal myeloperoxidase (MPO) activity, intestinal contents of TNF-α, IL-10 and HO-1, and intestinal Chiu's score were determined. Results showed that in N group, the HO-1 content increased after LL-HO-1 treatment, and significant difference was observed in HO1t group and HO2t group (P<0.05). In H groups, MPO activity and Chiu's score decreased, but IL-10 content increased in LL-HO-1-treated groups when compared with PBS and LL groups (P<0.05). When compared with N group, the MPO activity reduced dramatically in LL-HO-1-treated groups. Thus, in healthy rats (N group), intragastrical LL-HO-1 treatment may increase the intestinal HO-1 expression, but has no influence on the intestinal barrier. In hemorrhagic shock rats, LL-HO-1 may significantly protect the intestinal barrier, and repeating the intragastrical LL-HO-1 treatments twice has the most obvious protection.