Modulation of the monocyte/macrophage system in heart failure by targeting heme oxygenase-1

MicroRNAs in meningiomas: Potential biomarkers and therapeutic targets

Meningiomas, characterized primarily as benign intracranial or spinal tumors, present distinctive challenges due to their variable clinical behavior, with certain cases exhibiting aggressive features linked to elevated morbidity and mortality. Despite their prevalence, the underlying molecular mechanisms governing the initiation and progression of meningiomas remain insufficiently understood. MicroRNAs (miRNAs), small endogenous non-coding RNAs orchestrating post-transcriptional gene expression, have garnered substantial attention in this context. They emerge as pivotal biomarkers and potential therapeutic targets, offering innovative avenues for managing meningiomas. Recent research delves into the intricate mechanisms by which miRNAs contribute to meningioma pathogenesis, unraveling the molecular complexities of this enigmatic tumor. Meningiomas, originating from arachnoid meningothelial cells and known for their gradual growth, constitute a significant portion of intracranial tumors. The clinical challenge lies in comprehending their progression, particularly factors associated with brain invasion and heightened recurrence rates, which remain elusive. This comprehensive review underscores the pivotal role of miRNAs, accentuating their potential to advance our comprehension of meningioma biology. Furthermore, it suggests promising directions for developing diagnostic biomarkers and therapeutic interventions, holding the promise of markedly improved patient outcomes in the face of this intricate and variable disease.

Metabolism Serves as a Bridge Between Cardiomyocytes and Immune Cells in Cardiovascular Diseases

Metabolic disorders of cardiomyocytes play an important role in the progression of various cardiovascular diseases. Metabolic reprogramming can provide ATP to cardiomyocytes and protect them during diseases, but this transformation also leads to adverse consequences such as oxidative stress, mitochondrial dysfunction, and eventually aggravates myocardial injury. Moreover, abnormal accumulation of metabolites induced by metabolic reprogramming of cardiomyocytes alters the cardiac microenvironment and affects the metabolism of immune cells. Immunometabolism, as a research hotspot, is involved in regulating the phenotype and function of immune cells. After myocardial injury, both cardiac resident immune cells and heart-infiltrating immune cells significantly contribute to the inflammation, repair and remodeling of the heart. In addition, metabolites generated by the metabolic reprogramming of immune cells can further affect the microenvironment, thereby affecting the function of cardiomyocytes and other immune cells. Therefore, metabolic reprogramming and abnormal metabolite levels may serve as a bridge between cardiomyocytes and immune cells, leading to the development of cardiovascular diseases. Herein, we summarize the metabolic relationship between cardiomyocytes and immune cells in cardiovascular diseases, and the effect on cardiac injury, which could be therapeutic strategy for cardiovascular diseases, especially in drug research.

Iron Dyshomeostasis and Mitochondrial Function in the Failing Heart: A Review of the Literature

Cardiac contraction and relaxation require a substantial amount of energy provided by the mitochondria. The failing heart is adenosine triphosphate (ATP)- and creatine-depleted. Studies have found iron is involved in almost every aspect of mitochondrial function, and previous studies have shown myocardial iron deficiency in heart failure (HF). Many clinicians advocated intravenous iron repletion for HF patients meeting the conventional criteria for systemic iron deficiency. While clinical trials showed improved quality of life, iron repletion failed to significantly impact survival or significant cardiovascular adverse events. There is evidence that in HF, labile iron is trapped inside the mitochondria causing oxidative stress and lipid peroxidation. There is also compelling preclinical evidence demonstrating the detrimental effects of both iron overload and depletion on cardiomyocyte function. We reviewed the mechanisms governing myocardial and mitochondrial iron content. Mitochondrial dynamics (i.e., fusion, fission, mitophagy) and the role of iron were also investigated. Ferroptosis, as an important regulated cell death mechanism involved in cardiomyocyte loss, was reviewed along with agents used to manipulate it. The membrane stability and iron content of mitochondria can be altered by many agents. Some studies are showing promising improvement in the cardiomyocyte function after iron chelation by deferiprone; however, whether the in vitro and in vivo findings will be reflected on on clinical grounds is still unclear. Finally, we briefly reviewed the clinical trials on intravenous iron repletion. There is a need for more well-simulated animal studies to shed light on the safety and efficacy of chelation agents and pave the road for clinical studies.

Comparative single-cell profiling reveals distinct cardiac resident macrophages essential for zebrafish heart regeneration

Zebrafish exhibit a robust ability to regenerate their hearts following injury, and the immune system plays a key role in this process. We previously showed that delaying macrophage recruitment by clodronate liposome (-1d_CL, macrophage-delayed model) impairs neutrophil resolution and heart regeneration, even when the infiltrating macrophage number was restored within the first week post injury (Lai et al., 2017). It is thus intriguing to learn the regenerative macrophage property by comparing these late macrophages vs. control macrophages during cardiac repair. Here, we further investigate the mechanistic insights of heart regeneration by comparing the non-regenerative macrophage-delayed model with regenerative controls. Temporal RNAseq analyses revealed that -1d_CL treatment led to disrupted inflammatory resolution, reactive oxygen species homeostasis, and energy metabolism during cardiac repair. Comparative single-cell RNAseq profiling of inflammatory cells from regenerative vs. non-regenerative hearts further identified heterogeneous macrophages and neutrophils, showing alternative activation and cellular crosstalk leading to neutrophil retention and chronic inflammation. Among macrophages, two residential subpopulations (hbaa+ Mac and timp4.3+ Mac 3) were enriched only in regenerative hearts and barely recovered after +1d_CL treatment. To deplete the resident macrophage without delaying the circulating macrophage recruitment, we established the resident macrophage-deficient model by administrating CL earlier at 8 d (-8d_CL) before cryoinjury. Strikingly, resident macrophage-deficient zebrafish still exhibited defects in revascularization, cardiomyocyte survival, debris clearance, and extracellular matrix remodeling/scar resolution without functional compensation from the circulating/monocyte-derived macrophages. Our results characterized the diverse function and interaction between inflammatory cells and identified unique resident macrophages prerequisite for zebrafish heart regeneration.

Physiologically Relevant Levels of Biliverdin Do Not Significantly Oppose Oxidative Damage in Plasma In Vitro

AbstractAntioxidants have important physiological roles in limiting the amount of oxidative damage that an organism experiences. One putative antioxidant is biliverdin, a pigment that is most commonly associated with the blue or green colors of avian eggshells. However, despite claims that biliverdin functions as an antioxidant, neither the typical physiological concentrations of biliverdin in most species nor the ability of biliverdin to oppose oxidative damage at these concentrations has been examined. Therefore, we quantified biliverdin in the plasma of six bird species and found that they circulated levels of biliverdin between 0.02 and 0.5 μM. We then used a pool of plasma from northern bobwhite quail (Colinus virginianus) and spiked it with one of seven different concentrations of biliverdin, creating plasma-based solutions ranging from 0.09 to 231 μM biliverdin. We then compared each solution's ability to oppose oxidative damage in response to hydrogen peroxide relative to a control addition of water. We found that hydrogen peroxide consistently induced moderate amounts of oxidative damage (quantified as reactive oxygen metabolites) but that no concentration of biliverdin ameliorated this damage. However, biliverdin and hydrogen peroxide interacted, as the amount of biliverdin in hydrogen peroxide-treated samples was reduced to approximately zero, unless the initial concentration was over 100 μM biliverdin. These preliminary findings based on in vitro work indicate that while biliverdin may have important links to metabolism and immune function, at physiologically relevant concentrations it does not detectably oppose hydrogen peroxide-induced oxidative damage in plasma.

Bile pigments in emergency and critical care medicine

Bile pigments, such as bilirubin and biliverdin, are end products of the heme degradation pathway in mammals and are widely known for their cytotoxic effects. However, recent studies have revealed that they exert cytoprotective effects through antioxidative, anti-inflammatory, and immunosuppressive properties. All these mechanisms are indispensable in the treatment of diseases in the field of emergency and critical care medicine, such as coronary ischemia, stroke, encephalomyelitis, acute lung injury/acute respiratory distress syndrome, mesenteric ischemia, and sepsis. While further research is required before the safe application of bile pigments in the clinical setting, their underlying mechanisms shed light on their utilization as therapeutic agents in the field of emergency and critical care medicine. This article aims to summarize the current understanding of bile pigments and re-evaluate their therapeutic potential in the diseases listed above.

Macrophages in the heart: Active players or simple bystanders?

Today, more and more studies focus on the processes in which macrophages are involved. These discoveries provide new perspectives on the cellular mechanisms that regulate the physiological functions of the healthy heart. Moreover, they offer a deeper knowledge of the pathologic processes underlying the onset and the evolution of specific cardiac impairment. The heterogeneous population of macrophages within the heart can be divided by origin, expression profile, and function. The pool of cardiac macrophages includes at least two distinct subsets with different ontogeny. The first one has an embryonic origin, deriving from the yolk sac and the fetal liver, while the other macrophage subset results from the postnatal recruitment of monocytes produced in the bone marrow. This review will focus on new phenotypes and functions of cardiac macrophages that have been identified in the last years and that need to be deeply studied to unveil new potential therapies aimed at treating cardiac diseases.

Whole blood transcriptomic profiling identifies molecular pathways related to cardiovascular mortality in heart failure

AIMS

Chronic heart failure (CHF) is a systemic syndrome with a poor prognosis and a need for novel therapies. We investigated whether whole blood transcriptomic profiling can provide new mechanistic insights into cardiovascular (CV) mortality in CHF.

METHODS AND RESULTS

Transcriptome profiles were generated at baseline from 944 CHF patients from the BIOSTAT-CHF study, of whom 626 survived and 318 died from a CV cause during a follow-up of 21 months. Multivariable analysis, including adjustment for cell count, identified 1153 genes (6.5%) that were differentially expressed between those that survived or died and strongly related to a validated clinical risk score for adverse prognosis. The differentially expressed genes mainly belonged to five non-redundant pathways: adaptive immune response, proteasome-mediated ubiquitin-dependent protein catabolic process, T-cell co-stimulation, positive regulation of T-cell proliferation, and erythrocyte development. These five pathways were selectively related (RV coefficients >0.20) with seven circulating protein biomarkers of CV mortality (fibroblast growth factor 23, soluble ST2, adrenomedullin, hepcidin, pentraxin-3, WAP 4-disulfide core domain 2, and interleukin-6) revealing an intricate relationship between immune and iron homeostasis. The pattern of survival-associated gene expression matched with 29 perturbagen-induced transcriptome signatures in the iLINCS drug-repurposing database, identifying drugs, approved for other clinical indications, that were able to reverse in vitro the molecular changes associated with adverse prognosis in CHF.

CONCLUSION

Systematic modelling of the whole blood protein-coding transcriptome defined molecular pathways that provide a link between clinical risk factors and adverse CV prognosis in CHF, identifying both established and new potential therapeutic targets.

Cardiac protection induced by urocortin-2 enables the regulation of apoptosis and fibrosis after ischemia and reperfusion involving miR-29a modulation

Urocortin-2 (Ucn-2) has demonstrated cardioprotective actions against myocardial ischemia-reperfusion (I/R) injuries. Herein, we explored the protective role of Ucn-2 through microRNAs (miRNAs) post-transcriptional regulation of apoptotic and pro-fibrotic genes. We determined that the intravenous administration of Ucn-2 before heart reperfusion in a Wistar rat model of I/R recovered cardiac contractility and decreased fibrosis, lactate dehydrogenase release, and apoptosis. The infusion of Ucn-2 also inhibited the upregulation of 6 miRNAs in revascularized heart. The in silico analysis indicated that miR-29a and miR-451_1∗ are predicted to target many apoptotic and fibrotic genes. Accordingly, the transfection of neonatal rat ventricular myocytes with mimics overexpressing miR-29a, but not miR-451_1∗, prevented I/R-induced expression of pro- and anti-apoptotic genes such as Apaf-1, Hmox-1, and Cycs, as well as pro-fibrotic genes Col-I and Col-III. We also confirmed that Hmox-1, target of miR-29a, is highly expressed at the mRNA and protein levels in adult rat heart under I/R, whereas, Ucn-2 abolished I/R-induced mRNA and protein upregulation of HMOX-1. Interestingly, a significant upregulation of Hmox-1 was observed in the ventricle of ischemic patients with heart failure, correlating negatively with the left ventricle ejection fraction. Altogether, these data indicate that Ucn-2, through miR-29a regulation, provides long-lasting cardioprotection, involving the post-transcriptional regulation of apoptotic and fibrotic genes.

Kupffer Cells and Blood Monocytes Orchestrate the Clearance of Iron-Carbohydrate Nanoparticles from Serum

Intravenous (IV) iron nanoparticle preparations are widely used to treat iron deficiency. The mechanism of mononuclear phagocyte system-mediated clearance of IV iron nanoparticles is unknown. The early uptake and homeostasis of iron after injection of ferric carboxymaltose (FCM) in mice was studied. An increase in serum iron was observed at 2.5 h followed by a return to baseline by 24 h. An increase in circulating monocytes was observed, particularly Ly6C^hi and Ly6C^low. FCM was also associated with a time-dependent decrease in liver Kupffer cells (KCs) and increase in liver monocytes. The increase in liver monocytes suggests an influx of iron-rich blood monocytes, while some KCs underwent apoptosis. Adoptive transfer experiments demonstrated that following liver infiltration, blood monocytes differentiated to KCs. KCs were also critical for IV iron uptake and biodegradation. Indeed, anti-Colony Stimulating Factor 1 Receptor (CSF1R)-mediated depletion of KCs resulted in elevated serum iron levels and impaired iron uptake by the liver. Gene expression profiling indicated that C-C chemokine receptor type 5 (CCR5) might be involved in monocyte recruitment to the liver, confirmed by pharmaceutical inhibition of CCR5. Liver KCs play a pivotal role in the clearance and storage of IV iron and KCs appear to be supported by the expanded blood monocyte population.

LncRNA FENDRR promotes apoptosis of Leydig cells in late-onset hypogonadism by facilitating the degradation of Nrf2

This study aimed to investigate the role of lncRNA FENDRR in apoptosis of Leydig cells and the further mechanism. The apoptosis of Leydig cells (TM3 cell line) was induced by H₂O₂-treatment and detected by flow cytometry. The function of FENDRR was determined by in vitro and in vivo silencing experiments. The mechanism of FENDRR in regulating the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) was assessed by RNA immunoprecipitation, RNA pull-down, and ubiquitination assays. FENDRR expression was up-regulated in H₂O₂-treated TM3 cells. Knockdown of FENDRR augmented Nrf2 and HO-1 protein levels and testosterone production in H₂O₂-treated TM3 cells, whereas the apoptosis rate and caspase 3 activity were decreased. Mechanically, FENDRR bound to Nrf2 and promoted its ubiquitination and degradation. Nrf2 overexpression reversed the effects FENDRR overexpression on apoptosis, caspase 3 activity, and testosterone concentration in H₂O₂-treated TM3 cells. The in vivo experiments showed that FENDRR silence increased serum testosterone level and improved testosterone-related anti-depression behaviors of late-onset hypogonadism (LOH) mice. Our findings suggested that FENDRR could promote apoptosis of Leydig cells in LOH partly through facilitating Nrf2 degradation.

Didymin attenuates doxorubicin-induced cardiotoxicity by inhibiting oxidative stress

Objective

This study was designed to investigate the protective effects of didymin (Did) on doxorubicin (DOX)-induced cardiotoxicity.

Methods

After pretreatment with Did (2, 4, 8 mg/kg intraperitoneal i.p.) for 7 d, the male C57 mice were injected with single dose of DOX (20 mg/kg i.p.). The cardioprotective effect of Did was observed on the 7th day after DOX treatment.

Results

DOX delayed body growth and caused cardiac tissue injury, oxidative stress, and mitochondrial dysfunction. Similar experiments in H9C2 cardiomyocytes showed that DOX reduced cell viability, increased generation of reactive oxygen species (ROS) and fragmentation of DNA, decreased mitochondrial membrane potential, and induced cardiomyocyte apoptosis. However, all of these adverse effects were suppressed by Did pretreatment. Did increased protein expression of glutamate-L-cysteine ligase catalytic subunit (GCL), heme oxygenase 1 (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2). Besides, Did also induced activation of PI3K/AKT.

Conclusion

These findings indicated Did prevented DOX-induced cardiac injury and apoptosis via activating PI3K/AKT/Nrf2 signaling pathway.

Cardiac function dependence on carbon monoxide

Nitric oxide, studied to evaluate its role in cardiovascular physiology, has cardioprotective and therapeutic effects in cellular signaling, mitochondrial function, and in regulating inflammatory processes. Heme oxygenase (major role in catabolism of heme into biliverdin, carbon monoxide (CO), and iron) has similar effects as well. CO has been suggested as the molecule that is responsible for many of the above mentioned cytoprotective and therapeutic pathways as CO is a signaling molecule in the control of physiological functions. This is counterintuitive as toxic effects are related to its binding to hemoglobin. However, CO is normally produced in the body. Experimental evidence indicates that this toxic gas, CO, exerts cytoprotective properties related to cellular stress including the heart and is being assessed for its cytoprotective and cytotherapeutic properties. While survival of adult cardiomyocytes depends on oxidative phosphorylation (survival and resulting cardiac function is impaired by mitochondrial damage), mitochondrial biogenesis is modified by the heme oxygenase-1/CO system and can result in promotion of mitochondrial biogenesis by associating mitochondrial redox status to the redox-active transcription factors. It has been suggested that the heme oxygenase-1/CO system is important in differentiation of embryonic stem cells and maturation of cardiomyocytes which is thought to mitigate progression of degenerative cardiovascular diseases. Effects on other cardiac cells are being studied. Acute exposure to air pollution (and, therefore, CO) is associated with cardiovascular mortality, myocardial infarction, and heart failure, but changes in the endogenous heme oxygenase-1 system (and, thereby, CO) positively affect cardiovascular health. We will review the effect of CO on heart health and function in this article.

P38 MAPK and Nrf2 Activation Mediated Naked Gold Nanoparticle Induced Heme Oxygenase-1 Expression in Rat Aortic Vascular Smooth Muscle Cells

BACKGROUND AND AIMS

Heme oxygenase 1 (HO-1) is mainly regulated by the redox-sensitive transcription factor, namely nuclear factor erythroid 2-related factor 2 (Nrf2). We previously found a physically-made gold nanoparticle (GNP) can affect migration, adhesion, and proliferation of rat aortic vascular smooth muscle cells (VSMCs). This study was sought to investigate whether the GNP can affect HO-1 expression level in VSMCs.

METHODS

Cellular fractionation, Western blotting, and immunofluorescence microscopy were used to determine Nrf2 translocation and phosphorylation. SiRNA interference was used to examine role of Nrf2 in GNP-induced HO-1 expression.

RESULTS

The GNP concentration- and time-dependently enhanced HO-1 protein and mRNA expression; however, the mRNA induction was declined after 16 h treatment. The GNP treatment caused Nrf2 expression level and phosphorylation. In addition, it induced cytosolic Nrf2 translocation into nucleus. The HO-1 induction was inhibited by a ROS scavenger N-acetylcysteine (NAC), thiol-containing antioxidants (glutathione [GSH] and dithiothreitol [DTT]), JNK and p38 MAPK inhibitors, and nuclear transport inhibitor leptomycin. Meanwhile, the GNP-induced Nrf2 translocation (activation) was also reduced by NAC, JNK and p38 MAPK inhibitors, and nuclear transport inhibitor. Intriguingly, the GNP only enhanced activation of p38 MAPK but not JNK1/2. Finally, introduction of Nrf2 siRNA to cells to knockdown Nrf2 expression significantly inhibited GNP-induced HO-1 protein expression.

CONCLUSIONS

This study elucidates the action mechanism that the naked physically-made GNP can enhance HO-1 expression in rat aortic VSMCs by inducing Nrf2 expression and phosphorylation and translocation into nucleus. The Nrf2 activation is mediated through a redox-related reaction and p38 MAPK activation.

[Research progress in mesenchymal stem cells modified by Heme oxygenase 1]

Objective

To review the literature reports on research progress of Heme oxygenase 1 (HO-1) modified mesenchymal stem cells (MSCs).

Methods

The significance, effects, and related mechanism of HO-1 modification of MSCs were summarized by consulting the related literatures and reports of HO-1 modification of MSCs.

Results

HO-1 modification of MSCs has important research value. It can effectively enhance the anti-oxidative stress and anti-apoptotic properties of MSCs in complex internal environment after transplantation into vivo. It can also effectively enhance the immune regulation function of MSCs. It can improve the anti-injury, repair, and immune regulation effect of MSCs in various disease models and research fields.

Conclusion

The basic research of HO-1 modified MSCs has made remarkable progress, which is expected to be applied in clinical trials and provide theoretical basis and reference value for stem cell therapy.

Protective Effect of Phloroglucinol on Oxidative Stress-Induced DNA Damage and Apoptosis through Activation of the Nrf2/HO-1 Signaling Pathway in HaCaT Human Keratinocytes

Phloroglucinol (PG) is a component of phlorotannins, which are abundant in marine brown alga species. Recent studies have shown that PG is beneficial in protecting cells from oxidative stress. In this study, we evaluated the protective efficacy of PG in HaCaT human skin keratinocytes stimulated with oxidative stress (hydrogen peroxide, H₂O₂). The results showed that PG significantly inhibited the H₂O₂-induced growth inhibition in HaCaT cells, which was associated with increased expression of heme oxygenase-1 (HO-1) by the activation of nuclear factor erythroid 2-related factor-2 (Nrf2). PG remarkably reversed H₂O₂-induced excessive ROS production, DNA damage, and apoptosis. Additionally, H₂O₂-induced mitochondrial dysfunction was related to a decrease in ATP levels, and in the presence of PG, these changes were significantly impaired. Furthermore, the increases of cytosolic release of cytochrome c and ratio of Bax to Bcl-2, and the activation of caspase-9 and caspase-3 by the H₂O₂ were markedly abolished under the condition of PG pretreatment. However, the inhibition of HO-1 function using zinc protoporphyrin, a HO-1 inhibitor, markedly attenuated these protective effects of PG against H₂O₂. Overall, our results suggest that PG is able to protect HaCaT keratinocytes against oxidative stress-induced DNA damage and apoptosis through activating the Nrf2/HO-1 signaling pathway.

Protective Effect of Glutathione against Oxidative Stress-induced Cytotoxicity in RAW 264.7 Macrophages through Activating the Nuclear Factor Erythroid 2-Related Factor-2/Heme Oxygenase-1 Pathway

Reactive oxygen species (ROS), products of oxidative stress, contribute to the initiation and progression of the pathogenesis of various diseases. Glutathione is a major antioxidant that can help prevent the process through the removal of ROS. The aim of this study was to evaluate the protective effect of glutathione on ROS-mediated DNA damage and apoptosis caused by hydrogen peroxide, H₂O₂, in RAW 264.7 macrophages and to investigate the role of the nuclear factor erythroid 2-related factor-2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. The results showed that the decrease in the survival rate of RAW 264.7 cells treated with H₂O₂ was due to the induction of DNA damage and apoptosis accompanied by the increased production of ROS. However, H₂O₂-induced cytotoxicity and ROS generation were significantly reversed by glutathione. In addition, the H₂O₂-induced loss of mitochondrial membrane potential was related to a decrease in adenosine triphosphate (ATP) levels, and these changes were also significantly attenuated in the presence of glutathione. These protective actions were accompanied by a increase in the expression rate of B-cell lymphoma-2 (Bcl-2)/Bcl-2-associated X protein (Bax) and poly(ADP-ribose) polymerase cleavage by the inactivation of caspase-3. Moreover, glutathione-mediated cytoprotective properties were associated with an increased activation of Nrf2 and expression of HO-1; however, the inhibition of the HO-1 function using an HO-1 specific inhibitor, zinc protoporphyrin IX, significantly weakened the cytoprotective effects of glutathione. Collectively, the results demonstrate that the exogenous administration of glutathione is able to protect RAW 264.7 cells against oxidative stress-induced mitochondria-mediated apoptosis along with the activity of the Nrf2/HO-1 signaling pathway.