High Heme Oxygenase-1 Expression Research Articles

HMOX1 regulates ferroptosis via mic14 and its impact on chemotherapy resistance in small-cell lung cancer.

This study aimed to investigate the role and molecular mechanism of heme oxygenase-1 (HMOX1) in chemotherapy resistance in small-cell lung cancer (SCLC). Employed bioinformatics, qPCR, and Western Blot to assess HMOX1 levels in SCLC versus normal tissues and its prognostic relevance. CCK-8, flow cytometry, and thiobarbituric acid assays determined HMOX1's impact on SCLC chemosensitivity, ferroptosis markers, lipid peroxidation, and mic14's role in chemoresistance. In the GSE40275 and GSE60052 cohorts, HMOX1 expression was downregulated in SCLC tissues compared to normal tissues. Higher HMOX1 expression was associated with improved prognosis in the Sun Yat-sen University Cancer Hospital cohort and GSE60052 cohort. The RNA and protein levels of HMOX1 were reduced in drug-resistant SCLC cell lines compared to chemosensitive cell lines. Upregulation of HMOX1 increased chemosensitivity and reduced drug resistance in SCLC, while downregulation of HMOX1 decreased chemosensitivity and increased drug resistance. Upregulation of HMOX1 elevated the expression of ferroptosis-related proteins ACSL4, CD71, Transferrin, Ferritin Heavy Chain, and Ferritin Light Chain, while decreasing the expression of GPX4 and xCT. Conversely, downregulation of HMOX1 decreased the expression of ACSL4, CD71, Transferrin, Ferritin Heavy Chain, and Ferritin Light Chain, while increasing the expression of GPX4 and xCT. Upregulation of HMOX1 promoted cellular lipid peroxidation, whereas downregulation of HMOX1 inhibited cellular lipid peroxidation. Upregulation of HMOX1 reduced the RNA level of mic14, while downregulation of HMOX1 increased the RNA level of mic14. mic14 exhibited inhibitory effects on cellular lipid peroxidation in SCLC cells and contributed to reduced chemosensitivity and increased drug resistance in chemoresistant SCLC cell lines. HMOX1 plays a role in ferroptosis by regulating mic14 expression, thereby reversing chemoresistance in SCLC.

Characterizing the Immature Immunophenotype of Sickle Cell Disease Monocytes during Vaso-Occlusive Crisis

Sickle cell disease (SCD) is marked by episodic vaso-occlusive crisis (VOC). Painful VOC is the leading cause of emergency room visits and hospitalization in SCD, contributing heavily to the morbidity and mortality of this disease. Recurrent VOC creates a pro-inflammatory state that induces phenotypic alterations in the innate immune system. This inflammation-induced immune profile remodeling results in chronically active monocytes and neutrophils that antagonizethe vascular endothelium and further predispose SCD patients to VOC. While the mechanism of neutrophil involvement in VOC has been elucidated, less is known about the pathologic role of monocytes. Monocytes are of particular interest to VOC pathophysiology because they are especially malleable to inflammatory signaling. Indeed, inflammatory disease states such as COPD, obesity and atherosclerosis are known to influence monocyte development and alter monocyte subpopulations. Recently, nonclassical monocytes (CD14 dimCD16 +) with high heme oxygenase-1 expression have been shown to have a critical role in preventing VOC, generating renewed interest in monocytes as a therapeutic focus in SCD. In this study, we describe the monocyte subsets found in SCD patients during VOC by performing immunophenotypic flow cytometric, enzymatic, and morphologic analysis on peripheral blood obtained during hospitalization for VOC. Herein, we add to the growing body of evidence suggesting aberrant monocyte populations underpin VOC pathophysiology. We found that SCD monocytes during VOC possess an immature phenotype as demonstrated by 1) decreased CD4 positivity (p < .01), 2) low α-naphthyl butyrate esterase (ANBE) expression, and 3) naïve morphologic features (high nuclear/cytoplasmic ratio, indented or less lobular nuclei, and decreased cytoplasmic vacuolization). We additionally found an increase in CD14 +CD16 -CD4 - monocytes (p < .01), a subset associated with the impaired immune response of post-trauma patients. Interestingly, we also found a large proportion of CD14 +CD4 -HLA-DR - monocytes which, under normal circumstances, are exclusively found in neonates (p < .01). Finally, we report an increase in nonclassical monocytes (CD14 dimCD16 +), providing further evidence for the connection between this subset and the molecular mechanisms driving VOC. Taken together, these findings suggest that SCD patients in VOC deploy relatively immature monocytes that possess a lower capacity for antigen presentation, likely contributing to the immune dysfunction observed in SCD.

Antitumor Effects of Pegylated Zinc Protoporphyrin-Mediated Sonodynamic Therapy in Ovarian Cancer.

Sonodynamic therapy (SDT) induces reactive oxygen species (ROS) to kill tumor cells. Heme oxygenase-1 (HO-1), as an important antioxidant enzyme, resists killing by scavenging ROS. Zinc protoporphyrin (ZnPP) not only effectively inhibits HO-1 activity, but also becomes a potential sonosensitizer. However, its poor water solubility limits its applications. Herein, we developed an improved water-soluble method. It was proved that pegylated zinc protoporphyrin-mediated SDT (PEG-ZnPP-SDT) could significantly enhance ROS production by destroying the HO-1 antioxidant system in ovarian cancer. Increased ROS could cause mitochondrial membrane potential collapse, release cytochrome c from mitochondria to the cytoplasm, and trigger the mitochondrial-caspase apoptotic pathway. In conclusion, our results demonstrated that PEG-ZnPP-SDT, as a novel sonosensitizer, could improve the antitumor effects by destroying the HO-1 antioxidant system. It provided a new therapeutic strategy for SDT to treat cancers, especially those with higher HO-1 expression.

Iron cycle disruption by heme oxygenase-1 activation leads to a reduced breast cancer cell survival

Heme oxygenase-1 (HO-1), which catalyzes heme degradation releasing iron, regulates several processes related to breast cancer. Iron metabolism deregulation is also connected with several tumor processes. However the regulatory relationship between HO-1 and iron proteins in breast cancer remains unclear. Using human breast cancer biopsies, we found that high HO-1 levels significantly correlated with low DMT1 levels. Contrariwise, high HO-1 levels significantly correlated with high ZIP14 and prohepcidin expression, as well as hemosiderin storage. At mRNA level, we found that high HO-1 expression significantly correlated with low DMT1 expression but high ZIP14, L-ferritin and hepcidin expression. In in vivo experiments in mice with genetic overexpression or pharmacological activation of HO-1, we detected the same expression pattern observed in human biopsies. In in vitro experiments, HO-1 activation induced changes in iron proteins expression leading to an increase of hemosiderin, ROS levels, lipid peroxidation and a decrease of the growth rate. Such low growth rate induced by HO-1 activation was reversed when iron levels or ROS levels were reduced. Our findings demonstrate an important role of HO-1 on iron homeostasis in breast cancer. The changes in iron proteins expression when HO-1 is modulated led to the iron accumulation deregulating the iron cell cycle, and consequently, generating oxidative stress and low viability, all contributing to impair breast cancer progression.

HMOX1 Attenuates the Sensitivity of Hepatocellular Carcinoma Cells to Sorafenib via Modulating the Expression of ABC Transporters.

Hepatocellular carcinoma (HCC) represents a common malignancy, and mechanisms of acquired sorafenib resistance during the treatment of HCC patients remain elusive. The present study performed integrated bioinformatics analysis and explored the potential action of heme oxygenase 1 (HMOX1) in sorafenib-resistant HCC cells. Differentially expressed genes (DEGs) of the sorafenib-resistant group as compared to the sorafenib-sensitive group from GSE140202 and GSE143233 were extracted. Fifty common DEGs between GSE140202 and GSE143233 were extracted. Ten hub genes were identified from the protein-protein interaction network based on common DEGs. Experimental results revealed the upregulation of HMOX1 in sorafenib-resistant HCC cells. HMOX1 silence promoted the sensitivity to sorafenib in sorafenib-resistant HCC cells; overexpression of HMOX1 attenuated the sensitivity. In addition, HMOX1 silence downregulated the mRNA expression of ABC transporters in sorafenib-resistant HCC cells, while HMOX1 overexpression upregulated mRNA expression of ABC transporter expression in HCC cells. Further analysis also revealed that high expression of HMOX1 was associated with shorter OS and DSS in HCC patients. In conclusion, our analysis identified ten hub genes associated with sorafenib resistance in HCC. Further validation studies demonstrated that HMOX1 promoted sorafenib resistance of HCC cells via modulating ABC transporter expression.

Predictive and prognostic effect of HO-1 expression inbreast cancer patients undergoingneoadjuvant chemotherapy.

Heme oxygenase-1 (HO-1) has complex biological function, and is a candidate oncogene with a wide variety of deleterious functions in breast cancer. Here, we evaluated the relationship between expression of HO-1 protein with clinical response to neoadjuvant chemotherapy (NAC) in breast cancer patients. We used immunohistochemistry (IHC) to determine expression of HO-1 protein from core needle biopsy before NAC, then applied univariate and multivariate analyses to understand the relationship between HO-1 with pathological complete response (pCR) outcomes. Next, Kaplan-Meier and Log-rank tests were used to compare disease-free survival (DFS) and overall survival (OS), between groups, and Cox proportional hazards regression analysis applied for prognostic evaluation. A total of 575 patients with locally advanced invasive breast cancer were included in the study, of which 111 (19.3%) achieved pCR after NAC. Results from multivariate analysis showed that high HO-1 expression was an independent predictor of low pCR rate (OR 0.254, 95% CI 0.026-0.643, p = 0.002). Moreover, results from survival analysis showed that high HO-1 expression was significantly associated with shorter DFS (HR 4.843, 95% CI 1.205-32.572, p = 0.026), but not with OS (HR 3.219, 95% CI 0.928-32.124, p = 0.071). Furthermore, HO-1 expression was significantly associated with lower pCR rate (OR 0.102, 95% CI 0.013-0.352), p = 0.001), poor DFS (HR 8.562, 95% CI 1.592-34.950, p = 0.009), and OS (HR 7.835, 95% CI 1.220-56.213, p = 0.023) of patients with triple-negative breast cancer (TNBC) patients. Our results indicated that HO-1 expression is not only a biomarker for predicting pCR, but also a prognostic factor in breast cancer patients in a neoadjuvant setting, especially in TNBC subgroups.

Heme oxygenase-1 alleviates advanced glycation end product-induced oxidative stress, inflammatory response and biological behavioral disorders in rat dermal fibroblasts.

Advanced glycation end products (AGEs) are involved in delaying the wound healing of diabetic foot ulcers. The present study investigated the effects of heme oxygenase-1 (HO-1) on oxidative stress, inflammatory insult and biological behaviors in rat dermal fibroblasts in the presence of AGEs. Rat dermal fibroblasts were cultured in the presence of AGEs (100 µg/ml), glucose (1.0 g/l or 4.5 g/l), hemin (5 µM) and chromium mesoporphyrin (CrMP; 20 µM). A bilirubin kit, reverse transcription-quantitative PCR and western blotting were used to measure the activity and mRNA and protein levels of HO-1, respectively. ELISA kits were used to measure the levels of reactive oxygen species (ROS), malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), TNF-α, IL-6, IL-1β and the viability and collagen (hydroxyproline) secretion of fibroblasts. Cell proliferation and apoptosis were measured via flow cytometry. The scratch test was performed to evaluate cell migration. The results revealed that AGEs resulted in oxidative stress, inflammatory response and biological behavioral disorders in fibroblasts, while worsened functional disorders were caused by the combination of AGEs and high-glucose treatment. Hemin treatment induced sustained high HO-1 expression, decreased the levels of ROS, MDA, 8-OHdG, TNF-α, IL-6, IL-1β and cell apoptosis, and increased cellular collagen synthesis, viability, proliferation and migration, whereas CrMP abolished the effects of hemin. It was observed that high HO-1 expression reversed the AGE-induced oxidative stress, inflammatory response and biological behavioral disorders in fibroblasts, but fibroblast function did not return to that observed under normal glucose levels. In conclusion, it was demonstrated that hemin treatment induced high HO-1 expression. HO-1 reduced the AGE-induced functional disorders in fibroblasts and may accelerate the healing of diabetic wounds by improving fibroblast biological behaviors and reducing the oxidative stress and inflammatory response.

Heme Oxygenase-1 Protects Bone Marrow Mesenchymal Stem Cells Against Iron Overload through Decreasing ROS and Promoting IL-10 Generation

Background:Iron overload caused by frequent transfusions of suspended red blood cells which is of major concern in hematological disease. Heme oxygenase-1(HO-1) is well known as a crucial factor to cells against oxidative stress. In this study, significant upregulation of HO-1 was observed in bone marrow mesenchymal stem cells (BMMSCs) in the early phase of IO and predicted good prognosis in mice.Aim: Given that the role of HO-1 in protecting (BMMSCs) against damage from IO was still unknown. In the study, we investigated the effects and mechanisms of iron overload-related ROS by inducing IL-10 by regulating HO-1.METHODS:Male C57BL/6Ly5.2 (Ly45.2) mice were housed under specific pathogen-free conditions and allowed to acclimate for 2 weeks before experiments. The mice were housed (5 individuals per cage) and used at a weight of approximately 20.0 g. Thirty male mice were recipient mice, and another five were competitive mice. The thirty-five mice were randomly divided into four groups: (a) a control group; (b) an IO group (25 mg/ml); (c) an IO + hemin group and (d) an IO + ZnPP group. The depositions of iron in the liver, spleen and BM were assessed using HE staining and BM iron staining. Then, the expression of HO-1 and IL-10 were examined by Western blotting and q-PCR. Cell proliferation was measured by CCK-8 assay. The quantity of Ferritin, Serum iron, Hepcidin and IL-10 in the blood serum from iron overload cell were detected by ELISA in mouse model and iron overload patients. Finally, the levels of apoptotic rate, intracellular ROS and labile iron pool (LIP) were analyzed by flow cytometer.Result :We found that HO-1 was upregulated in the excess iron culture of BMMSCs in the early phase. Meanwhile, the apoptosis rate of IO BMMSCs was increased by 3.0 times compared with that of CON group. On the contrary, the apoptotic rate of BMMSCs down-regulated by transcription of si-HO-1 virus increased by 7.12 times compared to the CON group. In addition, the apoptosis rate of HO-1 overexpressing BMMSCs was significantly decreased in BM-1 virus transfected with HO-1 virus. Next, we also observed LIP in IO BMMSCs transfected with HO-1 virus was significantly lower than IO BMMSCs in un-transfected group. It suggested that HO-1 up-regulated the BMMSCs was protected from IO damage by decreasing intracellular iron content in vitro.To get an insight into the mechanism involved in cells protection from IO by HO-1 upregulation. We further explore production of ROS and secrection of IL10. As HO-1 was reported to have ability to reduce ROS, and IL-10 could promote excretion of intracellular iron. The results showed the ROS level in IO BMMSC was improved by 5.94 times compared with that of CON group, and the level of ROS in IO BMMSCs transcribed with si-HO-1 and HO-1 virus increased by 6.18 and 4.53 times, respectively. And IL-10 was increased significantly in the HO-1 up-regulated group.Next, we used U0126 (an ERK pathway inhibitor) to co-culture with IO BMMSCs that transcribed HO-1 virus. We observed the secretion of ferritin and the expression of IL-10 were consistent with the BMMSCs concentration changed. In vivo, we found that the serum iron and ferritin levels in the peripheral blood of IO mice were reduced by 1.92 and 1.3 times through ELISA analysis. The levels of IL-10 and ferritin were detected by ELISA. The results of deposition detection in bone marrow were consistent with the in vitro model. Finally, from November 2015 to December 2016, 12 patients diagnosed iron overload were enrolled. Including 6 males and 6 females, aged 44 to 77 years old. By q-PCR, we also found that iron overload in BMMSCs with high expression of HO-1 and IL-10 was reduced in serum ferritin after deferoxamine treatment. Therefore, we hypothesized that HO-1 overexpression of iron overload patients with better prognosis.Conclusions: we hypothesized that HO-1 overexpression of iron overload patients with better prognosis. The results of this study allow for further study of mechanisms of IO-related disease and provide new therapeutic targets for the treatment of IO patients. DisclosuresNo relevant conflicts of interest to declare.

Endothelin-1 as a Mediator of Heme Oxygenase-1-Induced Stemness in Colorectal Cancer: Influence of p53.

Heme oxygenase-1 (HO-1) is an antioxidant protein implicated in tumor progression, metastasis, and resistance to therapy. Elevated HO-1 expression is associated with stemness in several types of cancer, although this aspect has not yet been studied in colorectal cancer (CRC). Using an in vitro model, we demonstrated that HO-1 overexpression regulates stemness and resistance to 5-FU treatment, regardless of p53. In samples from CRC patients, HO-1 and endothelin converting enzyme-1 (ECE-1) expression correlated significantly, and p53 had no influence on this result. Carbon monoxide (CO) activated the ECE-1/endothelin-1 (ET-1) pathway, which could account for the protumoral effects of HO-1 in p53 wild-type cells, as demonstrated after treatment with bosentan (an antagonist of both ETRA and ETRB endothelin-1 receptors). Surprisingly, in cells with a non-active p53 or a mutated p53 with gain-of-function, ECE-1-produced ET-1 acted as a protective molecule, since treatment with bosentan led to increased efficiency for spheres formation and percentage of cancer stem cells (CSCs) markers. In these cells, HO-1 could activate or inactivate certain unknown routes that could induce these contrary responses after treatment with bosentan in our cell model. However more research is warranted to confirm these results. Patients carrying tumors with a high expression of both HO-1 and ECE-1 and a non-wild-type p53 should be considered for HO-1 based-therapies instead of ET-1 antagonists-based ones.

The protective effect of high heme oxygenase-1 expression induced by propofol on the alveolar II type epithelial cells of rats with acute lung injury induced by oleic acid.

This study aimed to investigate the mechanism of propofol (PR) pretreatment inducing high heme oxygenase-1 (HO-1) expression to protect alveolar type II epithelial cells (AEC-II) in rats with acute lung injury (ALI) induced by oleic acid (OA). In this study, 32 male Sprague-Dawley rats (250 - 300 g) were randomly divided into four groups (n = 8 in each group) as follows: group C (the normal control group), the OA group (the oleic acid injury control group), the OA + PR group (the PR pretreatment group), and the OA + IX group (the zinc porphyrin IX pretreatment group). Arterial blood gases, bronchoalveolar lavage fluid (BALF), and serum pulmonary surfactant-associated protein A (SP-A) were measured in each group. The changes in the AEC-II ultrastructure were observed under an electron microscope. The HO-1 protein expression was detected by immunohistochemistry, and HO-1 messenger ribonucleic acid (mRNA) was detected by polymerase chain reaction. The results of this study showed that there were significant differences in PO2, pCO2, and PaO2/FiO2 among the different groups (p < 0.05). The difference between BALF and SP-A in each group was statistically significant (p < 0.01). There were also significant differences in the integrated optical density of the HO-1 protein expression and HO-1 mRNA in the pulmonary tissue of the different groups (p < 0.05 or p < 0.01). The results of the electron microscopy showed that AEC-II were relatively irregular in the OA group. The cells degenerated and even disintegrated, the microvilli on the cell surface decreased, the lamellar bodies in the cytoplasm were evacuated, and some were discharged into the alveolar cavity. The above-mentioned changes in the OA + PR group were lower than in the OA group, while the changes were greater in the OA + IX group, compared with those in the OA group. We conclude that PR can significantly increase the expression of HO-1 in pulmonary tissues and reduce pulmonary injury, and, therefore, protect the AEC-II.

High expression of heme oxygenase-1 in tumor-associated macrophages characterizes a poor-prognosis subtype in nasopharyngeal carcinoma.

Tumor-associated macrophages (TAMs) are important components of the tumor microenvironment, which are characterized by pro-tumor M2 phenotype and correlate with poor survival of nasopharyngeal carcinoma (NPC). Heme oxygenase-1 (HO-1) plays a crucial role in macrophage polarization toward M2 phenotype, but its prognosis significance in NPC has been rarely determined. To gain insights into the HO-1 expression profile and to determine the clinical significance of HO-1 in NPC, we performed immunohistochemistry analyses in 126 NPC specimens. CD163, a highly specific marker of M2 macrophages, was used as a surrogate for the polarization state of TAMs. Our results showed that high expression of HO-1 and CD163 were detected in TAMs for 57.9% (73/126) and 61.9% (78/126) of the studied patients, and both of them were significantly associated with worse survival. Additionally, a significant correlation between the intensities of HO-1 and CD163 was identified, and HO-1 exhibited a superior ability in predicting survival compared with CD163. Our study revealed for the first time that overexpression of HO-1 characterized a poor-prognosis subtype in NPC. Individualized therapy targeting HO-1 might serve as a promising treatment modality for NPC.

Sex-, Age-, and Race/Ethnicity-Dependent Variations in Drug-Processing and NRF2-Regulated Genes in Human Livers.

Individual variations in xenobiotic metabolism affect the sensitivity to diseases. In this study, the impacts of sex, age, and race/ethnicity on drug-processing genes and nuclear factor erythroid 2-related factor 2 (NRF2) genes in human livers were examined via QuantiGene multiplex suspension array (226 samples) and quantitative polymerase chain reaction (qPCR) (247 samples) to profile the expression of nuclear receptors, cytochrome P450s, conjugation enzymes, transporters, bile acid metabolism, and NRF2-regulated genes. Sex differences were found in expression of about half of the genes, but in general the differences were not large. For example, females had higher transcript levels of catalase, glutamate-cysteine ligase catalytic subunit (GCLC), heme oxygenase 1 (HO-1), Kelch-like ECH-associated protein 1 (KEAP1), superoxide dismutase 1, and thioredoxin reductase-1 compared with males via qPCR. There were no apparent differences due to age, except children had higher glutamate-cysteine ligase modifier subunit (GCLM) and elderly had higher multidrug resistance protein 3. African Americans had lower expression of farnesoid X receptor (FXR) but higher expression of HO-1, Caucasians had higher expression of organic anion transporter 2, and Hispanics had higher expression of FXR, SULT2A1, small heterodimer partner, and bile salt export pump. An examination of 34 diseased and control human liver samples showed that compared with disease-free livers, fibrotic livers had higher NAD(P)H-quinone oxidoreductase 1 (NQO1), GCLC, GCLM, and NRF2; hepatocellular carcinoma had higher transcript levels of NQO1 and KEAP1; and steatotic livers had lower GCLC, GCLM, and HO-1 expression. In summary, in drug-processing gene and NRF2 genes, sex differences were the major findings, and there were no apparent age differences, and race/ethnicity differences occurred for a few genes. These descriptive findings could add to our understanding of the sex-, age-, and race/ethnicity-dependent differences in drug-processing genes as well as NRF2 genes in normal and diseased human livers. SIGNIFICANCE STATEMENT: In human liver drug-processing and nuclear factor erythroid 2-related factor 2 genes, sex differences were the main finding. There were no apparent differences due to age, except children had higher glutamate-cysteine ligase modifier subunit, and elderly had higher multidrug resistance protein 3. African Americans had lower expression of farnesoid X receptor (FXR) but higher expression of heme oxygenase 1, Caucasians had higher expression of organic anion transporter 2, and Hispanics had higher expression of FXR, small heterodimer partner, SULT2A1, and bile salt export pump.

CD56briCD27+CD11b+/- NK Cells Mediated Remission of Agvhd Via Immunoregulation

Background: In our previous study CD56briCD27+CD11b+/- NK cells show the potential of the remission of aGvHD, while the mechanism behind it is still unknown. Here, three hypothesis have been proposed according to further pilot experiment and literature. Method: 74 samples of patients after allo-HSCT were collected in the affiliated hospital of Guizhou medical university. Immunomonitoring with respect to the phenotype and function of CD56briCD27+CD11b+/- NK cells was performed on rested peripheral blood mononuclear cells (PBMCs) using multiparametric flow cytometry. Furthermore, the western-blot has been performed to determine the expression of HO-1 protein in sorted CD56briCD27+CD11b+/- NK cells as well. Result: (1) Our result shows a positive correlation between CD56briCD27+CD11b+/- NK cells and Th22, Tfh as well as Th1 like Tfh cells. Interestingly, a dramatic higher expression of homing marker CD62L has been observed on CD56briCD27+CD11b+/- NK cells. Thus we hypothesis that the CD56briCD27+CD11b+/- NK cells may migrate into the lymphoid tissues and regulate the differentiation of naïve T cells. (2) On the other hand, an elevated percentage of NKG2D has been found on CD56briCD27+CD11b+/- NK cells in patients with aGvHD. Meanwhile a high expression of Fas and exhaustion markers have been observed on CD4+ and CD8+ T cells. These results suggest that T cells may be eliminated by CD56briCD27+CD11b+/- NK cells. (3) Besides, our work displays that the expression of Heme Oxygenase-1 (HO-1) in CD56briCD27+CD11b+/- NK cells positively correlated with the secretion of IL-10. Compared with the patients with aGvHD, a higher expression of HO-1 and IL-10 in CD56briCD27+CD11b+/- NK cells has been found in patients without aGvHD at day 30 after allo-HSCT . Conclusion: According to these findings, the CD56briCD27+CD11b+/- NK cells may result in the remission of aGvHD via immunoregulation by regulation of T cells and secretion of IL-10. Disclosures No relevant conflicts of interest to declare.

Human monocyte-derived macrophages: Pathogenetic role in plaque rupture associated to systemic inflammation

BackgroundMacrophages play a key role in coronary plaque destabilization. In-vitro human monocyte-derived macrophages (MDMs) are used to study macrophages infiltrating tissue. Optical coherence tomography (OCT) provides an in-vivo insight of the coronary arteries. We compared the MDMs morpho-phenotype and culprit plaque features at OCT in acute coronary syndrome (ACS) patients according to the underlying plaque pathobiology. MethodsSixty-six patients undergoing coronary angiography and pre-angioplasty OCT of the culprit vessel were allocated to three groups according to mechanism of ACS at OCT and C-reactive protein levels (cut-off: 2 mg/Ll): 1) plaque rupture with systemic inflammation; 2) plaque rupture without systemic inflammation, 3) plaque with intact fibrous cap. A blood sample was collected to obtain MDMs, categorized as having “round” or “spindle” morphology. ResultsThirty-two patients (48.5%) were assigned to Group 1, 10 (15.2%) to Group 2 and 24 (36.4%) to Group 3. The “round” MDMs were significantly more frequent in Group 1 (39.25 ± 4.98%) than in Group 2 (23.89 ± 3.10%) and Group 3 (23.02 ± 7.89%), p = 0.008. MDMs in Group 1 as compared to Groups 2 and 3 showed lower efferocytosis (8.74 ± 1.38 vs 9.74 ± 2.15 vs 11.41 ± 2.41; p = 0.012), higher tissue factor levels (369.84 ± 101.13 vs 301.89 ± 59.78 vs 231.74 ± 111.47; p = 0.001) and higher heme oxygenase-1 expression (678.78 ± 145.43 vs 419.12 ± 74.44 vs 409.78 ± 64.33; p = 0.008). ConclusionsMDMs of ACS patients show morpho-phenotypic heterogeneity with prevalence of pro-thrombotic and pro-oxidative properties in case of plaque rupture and systemic inflammation. Such MDMs subpopulation may take part to the cellular pathways leading to fibrous cap rupture with the subsequent thrombus formation.

Neuroinflammation associates with antioxidant heme oxygenase-1 response throughout the brain in persons living with HIV

Previous studies showed that persons living with HIV (PLWH) demonstrate higher brain prefrontal cortex neuroinflammation and immunoproteasome expression compared to HIV-negative individuals; these associate positively with HIV levels. Lower expression of the antioxidant enzyme heme oxygenase 1 (HO-1) was observed in PLWH with HIV-associated neurocognitive impairment (HIV-NCI) compared to neurocognitively normal PLWH. We hypothesized that similar expression patterns occur throughout cortical, subcortical, and brainstem regions in PLWH, and that neuroinflammation and immunoproteasome expression associate with lower expression of neuronal markers. We analyzed autopsied brains (15 regions) from 9 PLWH without HIV-NCI and 7 matched HIV-negative individuals. Using Western blot and RT-qPCR, we quantified synaptic, inflammatory, immunoproteasome, endothelial, and antioxidant biomarkers, including HO-1 and its isoform heme oxygenase 2 (HO-2). In these PLWH without HIV-NCI, we observed higher expression of neuroinflammatory, endothelial, and immunoproteasome markers in multiple cortical and subcortical regions compared to HIV-negative individuals, suggesting a global brain inflammatory response to HIV. Several regions, including posterior cingulate cortex, globus pallidus, and cerebellum, showed a distinct pattern of higher type I interferon (IFN)-stimulated gene and immunoproteasome expression. PLWH without HIV-NCI also had (i) stable or higher HO-1 expression and positive associations between (ii) HO-1 and HIV levels (CSF, plasma) and (iii) HO-1 expression and neuroinflammation, in multiple cortical, subcortical, and brainstem regions. We observed no differences in synaptic marker expression, suggesting little, if any, associated neuronal injury. We speculate that this may reflect a neuroprotective effect of a concurrent HO-1 antioxidant response despite global neuroinflammation, which will require further investigation.

Overexpression of heme oxygenase-1 in bone marrow stromal cells promotes multiple myeloma resistance through the JAK2/STAT3 pathway

AimsBone marrow stromal cells (BMSCs) have been reported to interact with multiple myeloma (MM) and exert a vital function of the survival of MM cells. Heme oxygenase-1 (HO-1), a cytoprotective enzyme, has the potential to become a hematological malignancies targeted gene. This study aimed to investigate the role of HO-1 in MM resistance of BMSCs and its possible mechanisms. Main methodsIn this study, the expression of related proteins was detected by RT-qPCR and Western blot. HO-1 expression was regulated by lentivirus transfection. Cell viability and apoptosis were detected by Flow cytometry and CCK-8. Cytokine secretion was assayed by ELISA. The survival and carcinogenic abilities was detected by clone formation assay. Key findingsHO-1 expression in the BMSCs of stage III MM patients was substantially increased, compared with that of healthy donors and stage I/II patients. The results of co-culture of BMSCs and MM cells indicated that, the upregulated HO-1 inhibited the apoptosis of co-cultured MM cells, while downregulated HO-1 promoted the chemosensitivity of co-cultured MM cells, moreover, the upregulated HO-1 in BMSCs increased the colony-formation ability of MM cells. This protective capability may be regulated by CXCL12/CXCR4 signaling. High HO-1 expression in BMSCs can promote the phosphorylation of the JAK2/STAT3 pathway, thereby increasing secretion of SDF-1 in BMSCs and activating CXCL12/CXCR4 signaling. In addition, direct contact between BMSCs and MM cells may cause drug resistance. SignificanceThese results indicated that the regulation of HO-1 in BMSCs may be a new effective method of MM therapy.

Identification of HO-1 as a novel biomarker for graft acute cellular rejection and prognosis prediction after liver transplantation.

BackgroundLiver transplantation (LT) is the most effective treatment for patients with end-stage liver diseases, but acute rejection is still a major concern. However, the mechanisms underlying rejection remain unclear. Biomarkers are lacking for predicting rejection and long-term survival after LT.MethodsIsobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics was performed between acute cellular rejection (ACR) and non-rejection recipients. The molecular signature differences and potential biomarkers were identified by comprehensive bioinformatics. Heme oxygenase-1 (HO-1) expression and its association with clinical outcomes were investigated by tissue microarrays consisted of liver specimens from recipients with (n=80) and without ACR (n=57).ResultsA total of 287 differentially expressed proteins (DEPs) were identified. Pathway analysis revealed that T/B cell activation, integrin/inflammation signaling pathway, etc. were significantly correlated with ACR. Through comprehensive bioinformatics, HO-1 was identified as a candidate potential biomarker for ACR. In tissue microarray (TMA) analysis, HO-1 expression was significantly higher in ACR group than in non-rejection group (P<0.01). Preoperative Child-Pugh and Meld scores were significantly higher in recipients with high HO-1 expression (P<0.01). In a mean 5-year follow-up, recipients with high HO-1 expression were associated with a shorter overall survival (P<0.05). Further multivariate analyses indicated that HO-1 could be an independent adverse prognostic factor for post-transplant survival (P=0.005).ConclusionsA total of 287 DEPs were identified, providing a set of targets for further research. Recipients with high preoperative HO-1 expression were associated with ACR. HO-1 may be used as a potential biomarker for predicting the development of post-transplant allograft ACR and recipient’s survival.

The protective effect of human adiposederived mesenchymal stem cells on cisplatin-induced nephrotoxicity is dependent on their level of expression of heme oxygenase-1

The therapeutic efficacy of adipose mesenchymal stem cells (Ad-MSCs) for acute kidney injury (AKI) has been investigated extensively, and the anti-apoptotic, anti-inflammatory, and proangiogenic effects of heme oxygenase-1 (HO-1) reportedly ameliorate AKI. We hypothesized that the therapeutic efficacy of Ad-MSCs is dependent on their expression level of HO-1. The viability and migration ability of cisplatin-treated human renal proximal tubular epithelial cells were assessed. Sprague–Dawley rats were divided into control, cisplatin (10 mg/kg), and cisplatin plus Ad MSCs (with high and low HO-1 expression) groups. The HO-1 expression level in hAd-MSCs increased with increasing passage number, peaking at passage 4 and decreasing thereafter. The viability and migratory ability of hAd-MSCs with high HO-1 expression were greater than those of hAd-MSCs with low HO-1 expression. Renal tubular toxicity in cisplatin-treated rats was ameliorated by administration of hAd-MSCs with high HO-1 expression, although the levels of blood urea nitrogen and serum creatinine did not differ according to the level of HO-1 expression. The magnitude of reactive oxygen species induced DNA damage was lower in hAd-MSCs with high HO-1 expression than in those with low HO-1 expression. Administration of hAd-MSCs significantly suppressed cisplatin induced apoptosis. Also, hAd-MSCs with high HO-1 expression were more resistant to cisplatin-induced apoptosis than were those with low HO-1 expression. hAd MSCs with high HO-1 expression have therapeutic potential for cisplatin induced nephrotoxicity, based on our in vitro and in vivo results. These findings will facilitate the development of novel therapeutic strategies for cisplatin-induced AKI.

Heme Oxygenase-1 dictates innate – adaptive immune phenotype in human liver transplantation

Liver transplantation (LT) has become the standard of care for patients with end-stage liver disease and those with hepatic malignancies, while adaptive immune-dominated graft rejection remains a major challenge. Despite potent anti-inflammatory and cytoprotective functions of heme oxygenase-1 (HO-1) overexpression upon innate immune-driven hepatic ischemia reperfusion injury, its role in adaptive immune cell-driven responses remains to be elucidated. We analyzed human biopsies from LT recipients (n = 55) to determine putative association between HO-1 levels and adaptive/co-stimulatory gene expression programs in LT. HO-1 expression negatively correlated with innate (CD68, Cathepsin G, TLR4, CXCL10), adaptive (CD4, CD8, IL17) and co-stimulatory (CD28, CD80, CD86) molecules at the graft site. LT recipients with high HO-1 expression showed a trend towards improved overall survival. By demonstrating the association between graft HO-1 levels and adaptive/co-stimulatory gene programs, our study provides important insights to the role of HO-1 signaling in LT patients.

Activation of the Nrf2-ARE signal pathway after blast induced traumatic brain injury in mice

Background: Treatment of blast-induced traumatic brain injury (bTBI) has been hindered. Previous studies have demonstrated that oxidative stress may contribute to the pathophysiological process. The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway exhibits a protective effect after traumatic brain injury (TBI). This study explored whether the Nrf2-ARE pathway was activated in a modified bTBI mouse model.Method: Mice were randomly divided into six groups: the 6 h, 1 d, 3 d, 7 d and 14 d after bTBI groups and a sham group. The protein levels of nuclear Nrf2, heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO1) were detected using western blot, and HO-1 and NQO1 mRNA levels were determined by real-time quantitative polymerase chain reaction. Moreover, HO-1 and Nrf2 were localized using histological staining.Results: The protein level of the Nrf2-ARE pathway in the frontal lobe increased significantly in the 3 d after bTBI. The HO-1 and NQO1 mRNA levels also reached a peak in the frontal lobe 3 d after bTBI. The histological staining demonstrated higher expression of HO-1 in the frontal lobe and hippocampus 3 d after bTBI, when nuclear import of Nrf2 reached a peak in the frontal lobe.Conclusions: bTBI activated the Nrf2-ARE signaling pathway in the brain. The peak activation time in the frontal lobe may be 3 d after injury, and activating the Nrf2 pathway could be a new direction for treatment.