Hepcidin, a key regulator of iron metabolism, is synthesized by the liver. Hepcidin binds to the iron exporter ferroportin to regulate the release of iron into plasma from macrophages, hepatocytes, and enterocytes. We analyzed liver samples from patients undergoing hepatic surgery for cancer or receiving liver transplants and IntroductionHepcidin is a peptide found in human plasma and urine 1,2 and synthesized in the liver. 1-3 Studies in mice, humans, and cell cultures demonstrated that hepcidin mRNA levels were regulated by iron stores, 3 inflammation, 3,4-6 anemia, and hypoxia, 4 and influenced by the mouse strain and sex and transcription factors involved in hepatocyte differentiation. 7,8 Hepcidin-deficient mice accumulated iron in the liver and pancreas 9 and mice engineered to overexpress hepcidin were born with severe iron deficiency that was not corrected by iron supplementation. 10 Taken together these data suggested that hepcidin was a hormone involved in the regulation of iron metabolism. 9 Studies of patients with iron disorders demonstrated the involvement of hepcidin in regulation of iron metabolism during juvenile hemochromatosis, 11 classical HFE-related hemochromatosis, 12,13 and chronic inflammatory diseases. 5,14 Hepcidin appears to act by inhibiting cellular iron export through binding directly to the iron exporter ferroportin and inducing its internalization and degradation. 15 Recent understanding of iron metabolism in mice is based on measurements of hepatic hepcidin mRNA, whereas the corresponding human studies examine urinary hepcidin concentrations. We examined the correlation between hepcidin mRNA and urinary hepcidin concentrations in the context of human liver disease. Study design PatientsThirty-six patients, who were operated on for primary or secondary liver carcinoma or received transplants for cirrhosis, were included in this study.The patients with known HFE genetic hemochromatosis, expected to exhibit abnormal hepcidin regulation, 12,16 were excluded. The study was approved by the local ethics committee (CCPPRB) and informed consent was obtained from the patients.From each patient we collected clinical data and serum, urine, and nontumoral liver samples. Liver tissues were frozen in liquid nitrogen or fixed in formalin for histologic studies. The hepatic fibrosis status was evaluated according to the Metavir score 17 ; 20 samples had no or slight fibrosis, 7 samples were moderately fibrotic, and 9 samples were strongly fibrotic or cirrhotic. MethodsClinical laboratory studies. Clinical laboratory assays were performed at the Rennes University Hospital. The liver iron concentration (LIC) was evaluated as described previously. 18 Quantitative RT-PCR. Total RNAs were extracted using the SV Total RNA Isolation System (Promega, Madison, WI). Quality-checked RNA (1 g) was used for reverse transcription (RT) following the manufacturer's protocol (Advantage RT-for-PCR Kit, Clontech, Palo Alto, CA). We performed polymerase chain reactions (PCRs) in triplicate to evaluate the hepcidin...

Cyclin-dependent kinases trigger and coordinate transitions between different phases the cell division cycle (CDK1, 2, 3, 4, 6, 7). They also play a role in apoptosis (CDK2), in neuronal cells (CDK5) and in the control of transcription (CDK 7, 8, 9). Intensive screening has lead to the recent identification of a series of chemical inhibitors of CDKs: olomoucine, roscovitine, purvalanol, CVT -313, flavopiridol, y­ butyrolactone, indirubins, paullones and staurosporine. Some of these compounds display remarkable selectivities and efficiencies (IC5o < 25 nM). Many have been co-crystallised with CDK2 and their interactions with the kinase have been analysed in atomic detail. These inhibitors all act by competing with ATP for binding at the catalytic site. Most inhibitors present a flat heterocyclic ring system that occupies the purine binding pocket as well as form 2 or 3 hydrogen bonds with Glu-81 and Leu-83. The binding modes of these inhibitors are reviewed in this article. Knowledge of the CDK/inhibitor interactions will be of great help to design inhibitors with improved selectivity our potency as well as to generate affinity chromatography matrices for the purification and identification of their cellular targets. The potential use of CDK inhibitors is being extensively evaluated in cancer chemotherapy and other fields such as the cardiovascular domain (restenosis), dermatology (psoriasis), nephrology (glomerulonephritis) parasitology (unicellular parasites such as Plasmodium, Trypanosomes, Toxoplasm,...etc.), neurology (Alzheimer's disease) and viral infections (cytomegalovirus, H.I.V., herpes).