In the brain, the heme oxygenase (HO) system has been reported to be very active and its modulation seems to play a crucial role in the pathophysiology of neurodegenerative disorders. Hemin as HO-1 inducer has been shown to attenuate neuronal injury so the goal of this study was to assess the effect of hemin therapy on the acute stress and how it would modulate neurological outcome. Thirty male...

K562 human erythroleukemia cells are an established cell line derived from an adult with chronic myelogenous leukemia. Hemin stimulates their synthesis of embryonic and fetal hemoglobins. We have found that their globin synthetic pattern depends on the concentration of added hemin. Clone RA6 was cultured with 0--100 microM hemin and the globin synthetic pattern determined by 3H-leucine incorpor...

Heme uptake is a common means of iron and porphyrin acquisition by many pathogenic bacteria. The genus Haemophilus includes several important pathogenic bacterial species that characteristically require hemin-, protoporphyrin-, or heme-substituted proteins as essential growth factors under aerobic conditions. However, the mechanism of heme transport is not understood for Haemophilus. We have cl...

Sickle hemoglobin is relatively unstable upon oxidation or mechanical shaking. During denaturation, it generates oxygen radicals and hemichromes and ultimately precipitates in the form of micro-Heinz bodies. It is not clear, however, whether the degradation product hemin, which is a potent hemolytic agent and a potential perturbant to protein-protein interactions in the red cell membrane skelet...

Epithelial‑mesenchymal transition (EMT) is a key mechanism underlying metastatic breast cancer. Reactive oxygen species (ROS) play an important role in EMT. Heme oxygenase‑1 (HMOX‑1) can reduce oxidative stress. However, the effect of HMOX‑1 on the EMT process in breast cancer cells is unknown. We treated the MCF‑7 breast cancer cell line with the HMOX‑1 inducer hemin and observed that hemin in...

The effect of hemin on the differentiation program of murine erythroleukemia (MEL) cells has been investigated. While hemin treatment does induce increased levels of globin mRNA and hemoglobin, it fails to lead to other biochemical changes associated with MEL cell differentiation induced by DMSO and thioguanine. These include increased levels of the nuclear protein IP25 and of the enzyme cytidi...

Epidemiological findings have indicated that red meat increases the likelihood of colorectal cancer. Aim of this study was to investigate whether hemoglobin, or its prosthetic group heme, in red meat, is a genotoxic risk factor for cancer. Human colon tumor cells (HT29 clone 19A) and primary colonocytes were incubated with hemoglobin/hemin and DNA damage was investigated using the comet assay. ...

The surface protein Shp of Streptococcus pyogenes rapidly transfers its hemin to HtsA, the lipoprotein component of the HtsABC transporter, in a concerted two-step process with one kinetic phase. The structural basis and molecular mechanism of this hemin transfer have been explored by mutagenesis and truncation of Shp. The heme-binding domain of Shp is in the amino-terminal region and is functi...

In intracerebral hemorrhage, microglia become rapidly activated and remove the deposited blood and cellular debris. To survive in a harmful hemorrhagic or posthemorrhagic condition, activated microglia must be equipped with appropriate self-defensive mechanism(s) to resist the toxicity of hemin, a component released from damaged RBCs. In the current study, we found that activation of microglia ...

In glomerulonephritis, there is intraglomerular activation of inducible nitric oxide synthase (iNOS) leading to high output production of nitric oxide (NO). This can result in supraphysiologic amounts of NO and cause oxidative injury. It is unknown whether mechanisms of cellular defense against NO-mediated injury exist. Induction of the heme catabolizing enzyme heme oxygenase-1 (HO-1), which ge...