Sedimentary Cobalt Protoporphyrin as a Potential Precursor of Prosthetic Heme Group for Bacteria Inhabiting Fossil Organic Matter-Rich Shale Rock

This study hypothesizes that bacteria inhabiting shale rock affect the content of the sedimentary cobalt protoporphyrin present in it and can use it as a precursor for heme synthesis. To verify this hypothesis, we conducted qualitative and quantitative comparative analyses of cobalt protoporphyrin as well as heme, and heme iron in shale rock that were (i) inhabited by bacteria in the field, (ii) treated with bacteria in the laboratory, and with (iii) bacterial culture on synthetic cobalt protoporphyrin. Additionally, we examined the above-mentioned samples for the presence of enzymes involved in the heme biosynthesis and uptake as well as hemoproteins. We found depletion of cobalt protoporphyrin and a much higher heme concentration in the shale rock inhabited by bacteria in the field as well as the shale rock treated with bacteria in the laboratory. Similarly, we observed the accumulation of protoporphyrin in bacterial cells grown on synthetic cobalt protoporphyrin. We detected numerous hemoproteins in metaproteome of bacteria inhabited shale rock in the field and in proteomes of bacteria inhabited shale rock and synthetic cobalt protoporhyrin in the laboratory, but none of them had all the enzymes involved in the heme biosynthesis. However, proteins responsible for heme uptake, ferrochelatase and sirohydrochlorin cobaltochelatase/sirohydrochlorin cobalt-lyase were detected in all studied samples.

Resistance Exercise Induces Heme Oxygenase-1 Expression to Promote Macrophage Polarization and Accelerate Catheter-related Thrombolysis and Recanalization in Rats

IntroductionCatheter-related thrombosis (CRT) is a major complication of central venous catheters. Resistance exercise to prevent CRT formation has been demonstrated, but there are few studies of CRT dissolution and recanalization. In this study, we focused on resistance exercise, heme oxygenase-1 (HO-1), and macrophage polarization to investigate the mechanism of resistance exercise accelerating thrombolysis and recanalization, providing a theoretical basis for resistance exercise adjuvant therapy of CRT.MethodsA rat CRT model was established and Intervened with resistance exercise and injection of HO-1 agonist cobalt protoporphyrin (COPP) and the inhibitor tin protoporphyrin IX(SnPP).Thrombolysis and recanalization were observed by hematoxylin and eosin(H&E). Neovascularization was detected by immunohistochemical CD31 staining. The levels of HO-1, IL-6, and IL-10 in the rat sera were determined by enzyme-linked immunosorbent assay (ELISA). The relative expression levels of HO-1, Arg-1, HO-1, CD206, and CD80 mRNA were detected by quantitative polymerase chain reaction (qPCR). The colocalization expression of HO-1 with CD206 and CD86 were detected by immunofluorescence.ResultsResistance exercise for 28 days could induce HO-1 expression, decrease IL-6 level, increase IL-10 level, increase Arg-1 and CD206 expression, decrease INOS and CD80 expression, and increase CD31 expression, and the co-localization expression of HO-1 and CD206 was significantly higher than that of HO-1 and CD86.ConclusionAfter 28 days of resistance exercise, mechanical stimulation can mediate the expression of HO-1 in macrophages, promote the polarization of M2 macrophages, exert the effects of anti-inflammation and promoting angiogenesis, and accelerate the dissolution and recanalization of CRT.

Heme Oxygenase-1 Induction by Cobalt Protoporphyrin Ameliorates Cholestatic Liver Disease in a Xenobiotic-Induced Murine Model

Cholestatic liver diseases can progress to end-stage liver disease and reduce patients’ quality of life. Although their underlying mechanisms are still incompletely elucidated, oxidative stress is considered to be a key contributor to these diseases. Heme oxygenase-1 (HO-1) is a cytoprotective enzyme that displays antioxidant action. It has been found that this enzyme plays a protective role against various inflammatory diseases. However, the role of HO-1 in cholestatic liver diseases has not yet been investigated. Here, we examined whether pharmacological induction of HO-1 by cobalt protoporphyrin (CoPP) ameliorates cholestatic liver injury. To this end, a murine model of 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet feeding was used. Administration of CoPP ameliorated liver damage and cholestasis with HO-1 upregulation in DDC diet-fed mice. Induction of HO-1 by CoPP suppressed the DDC diet-induced oxidative stress and hepatocyte apoptosis. In addition, CoPP attenuated cytokine production and inflammatory cell infiltration. Furthermore, deposition of the extracellular matrix and expression of fibrosis-related genes after DDC feeding were also decreased by CoPP. HO-1 induction decreased the number of myofibroblasts and inhibited the transforming growth factor-β pathway. Altogether, these data suggest that the pharmacological induction of HO-1 ameliorates cholestatic liver disease by suppressing oxidative stress, hepatocyte apoptosis, and inflammation.

Molecular Dynamics of Cobalt Protoporphyrin Antagonism of the Cancer Suppressor REV-ERBβ

Nuclear receptor REV-ERBβ is an overexpressed oncoprotein that has been used as a target for cancer treatment. The metal-complex nature of its ligand, iron protoporphyrin IX (Heme), enables the REV-ERBβ to be used for multiple therapeutic modalities as a photonuclease, a photosensitizer, or a fluorescence imaging agent. The replacement of iron with cobalt as the metal center of protoporphyrin IX changes the ligand from an agonist to an antagonist of REV-ERBβ. The mechanism behind that phenomenon is still unclear, despite the availability of crystal structures of REV-ERBβ in complex with Heme and cobalt protoporphyrin IX (CoPP). This study used molecular dynamic simulations to compare the effects of REV-ERBβ binding to Heme and CoPP, respectively. The initial poses of Heme and CoPP in complex with agonist and antagonist forms of REV-ERBβ were predicted using molecular docking. The binding energies of each ligand were calculated using the MM/PBSA method. The computed binding affinity of Heme to REV-ERBβ was stronger than that of CoPP, in agreement with experimental results. CoPP altered the conformation of the ligand-binding site of REV-ERBβ, disrupting the binding site for nuclear receptor corepressor, which is required for REV-ERBβ to regulate the transcription of downstream target genes. Those results suggest that a subtle change in the metal center of porphyrin can change the behavior of porphyrin in cancer cell signaling. Therefore, modification of porphyrin-based agents for cancer therapy should be conducted carefully to avoid triggering unfavorable effects.

Light-Driven CO2 Reduction by Co-Cytochrome b562

The current trend in atmospheric carbon dioxide concentrations is causing increasing concerns for its environmental impacts, and spurring the developments of sustainable methods to reduce CO2 to usable molecules. We report the light-driven CO2 reduction in water in mild conditions by artificial protein catalysts based on cytochrome b562 and incorporating cobalt protoporphyrin IX as cofactor. Incorporation into the protein scaffolds enhances the intrinsic reactivity of the cobalt porphyrin toward proton reduction and CO generation. Mutations around the binding site modulate the activity of the enzyme, pointing to the possibility of further improving catalytic activity through rational design or directed evolution.

HCl-induced acute lung injury: a study of the curative role of mesenchymal stem/stromal cells and cobalt protoporphyrin

Background This study was designed to investigate bone marrow mesenchymal stem/stromal cells (BM-MSCs) and cobalt protoporphyrin (CoPP) curable effects on HCl-induced acute lung injury (ALI) and its underlying mechanisms hoping this might aid to offer a therapeutic opportunity for ALI. Results Forty male Sprague Dawley rats were randomly allocated into four groups; normal (normal rats), ALI (rats injected with 2 ml hydrochloric acid (HCl)/kg via trachea), ALI + BM-MSCs (ALI rats intravenously injected twice with 1 × 106 BM-MSCs/rat/week), and ALI + CoPP (ALI rats intraperitoneally injected twice with CoPP (0.5 mg/100 g/week)). White blood cells (WBCs), red blood cells (RBCs), hemoglobin (Hb), serum tumor necrosis factor-alpha (TNF-α), lung histopathology, apoptosis markers (caspase-3 and Bcl2), and oxidative stress markers (malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT)) were measured. ALI caused increases in WBCs, TNF-α, caspase-3, and MDA, and morphological damage score of lungs with decreases in RBCs, Hb, Bcl2, SOD, and CAT (p < 0.05). BM-MSCs or CoPP treatment reversed these ALI-induced changes (p < 0.05) towards normal. Conclusions BM-MSCs and CoPP could attenuate ALI by modulation of inflammation, oxidative stress, and apoptosis. Curative roles of BM-MSCs were more effective than those of CoPP. This highlights BM-MSCs as a potent therapy for HCl-associated ALI.

Activation of Heme Oxygenase Expression by Cobalt Protoporphyrin Treatment Prevents Pneumonic Plague Caused by Inhalation of Yersinia pestis

ABSTRACT Pneumonic plague, caused by the Gram-negative bacteria Yersinia pestis, is an invasive, rapidly progressing disease with poor survival rates. Following inhalation of Y. pestis, bacterial invasion of the lungs and a tissue-damaging inflammatory response allows vascular spread of the infection. Consequently, primary pneumonic plague is a multiorgan disease involving sepsis and necrosis of immune tissues and the liver, as well as bronchopneumonia and rampant bacterial growth. Given the likely role of the hyperinflammatory response in accelerating the destruction of tissue, in this work we evaluated the therapeutic potential of the inducible cytoprotective enzyme heme oxygenase 1 (HO-1) against primary pneumonic plague. On its own, the HO-1 inducer cobalt protoporphyrin IX (CoPP) provided mice protection from lethal challenge with Y. pestis CO92 with improved pulmonary bacterial clearance and a dampened inflammatory response compared to vehicle-treated mice. Furthermore, CoPP treatment combined with doxycycline strongly enhanced protection in a rat aerosol challenge model. Compared to doxycycline alone, CoPP treatment increased survival, with a 3-log decrease in median bacterial titer recovered from the lungs and the general absence of a systemic hyperinflammatory response. In contrast, treatment with the HO-1 inhibitor SnPP had no detectable impact on doxycycline efficacy. The combined data indicate that countering inflammatory toxicity by therapeutically inducing HO-1 is effective in reducing the rampant growth of Y. pestis and preventing pneumonic plague.