All red blood cells, erythrocytes, originate in bone marrow. The process of their differentiation and maturation is called erythopoiesis and is regulated through hormone erythropoietin (EPO), which functions as a stimulatory factor for erythropoiesis. EPO is produced in kidney and its production is regulated by oxygen supplementation. EPO is transported to bone marrow via blood vessels. Chronic overproduction of erythrocytes leads to disease called polycythemia. Polycythemia may be diagnosed for example by measurement of haematocrit or haemoglobin concentration in blood. EPO level may or may not be increased. Patients suffering from polycythemia may or may not have any symptoms. It depends on manifestation level of the disease. The most common symptoms are higher blood pressure, headaches, dizziness, swelling and epistaxis. Recently, the most common treatment of polycythemia is phlebothomy. The aim of this master thesis is to unravel the role of a newly described mutation, which was found among members of one family suffering from polycythemia with increased EPO level. It is single substitution mutation -136 G > A in 5' UTR region of EPO gene. The clones of EPO producing cell lines bearing this mutation were prepared using CRISPR/Cas9 technology. Several experiments performed not only on those cell...

Iron is a metal element with crucial roles in human organism. Both iron deficiency and iron overload are important pathologies. Hepcidin, a peptide synthetized in the liver, is a key iron regulatory hormone. Increased amount of iron and inflammation stimulate its expression while iron deficiency and activated erythropoiesis cause hepcidin downregulation. The regulation of hepcidin expression on the molecular level and its hierarchy and interactions are not completely known. The main regulatory pathway is BMP/ SMAD which reacts to the iron amount in the organism. Several molecules, including hemojuvelin and HFE, are involved in this pathway and their mutations are linked to inappropriately low hepcidin production, iron overload and hereditary hemochromatosis. Erythroid regulation with suppressive action on hepcidin expression is known only partially as well as its connection to the BMP/ SMAD pathway. Recently, two new negative regulators of hepcidin expression have been described. Membrane enzyme present in hepatocytes - matriptase-2 (MT-2, TMPRSS6) and soluble factor secreted by erythroblasts - erythroferrone (ERFE). The aim of our work was to investigate how MT-2 is involved in the erythroid regulatory pathway, and whether it can represent the molecule where various regulatory pathways interact....

Myelodysplastic syndrome (MDS) with deletion of the long arm of the chromosome 5 (5q - syndrome, del( 5q)) can be characterized by anemia, macrocytosis, a normal or high platelet count, and hypolobulated megakaryocytes in the bone marrow. 5q - syndrome belongs to low - risk MDS, which means low risk to transform to acute myeloid leukemia. 5q - syndrome is ass ociated with female predominance and older age. Another sign is transfusion burden that is treated by erythropoiesis - stimulating agents (ESA) as erythropoietin (EPO). Moreover, the response of MDS patients is around 30 - 60% with the median of the response b eing ~ 24 months. The second line of treatment is lenalidomide (LEN) which is a derivate of teratogenic analog thalidomide. LEN increases erythropoiesis and inhibits the growth of del(5q) erythroid progenitors in vivo and it does not have a significant effe ct on the growth of normal CD34+ progenitors or cytogenetically normal progenitors in MDS with del(5q) clones. LEN is used as therapy in multiple myeloma, myelodysplastic syndrome, and lymphoma. LEN is an expensive agent and not every MDS patient re sponds to this therapy. This is a reason why is a need to find a biomarker for the determination of successful treatment. Some multiple myeloma studies showed that cereblon can be the biomarker...