Expression and co-expression of surface markers of pluripotency on human amniotic cells cultured in different growth media

Objectives: Despite constant advances in the field of biology and medical application of human embryonic stem cells, the molecular mechanism of pluripotency remains largely unknown. So far, definitions of pluripotent stem cells (SC) have been based on a limited number of antigenic markers and have not allowed for unambiguous determination of the homogeneity of each subpopulation. Moreover, the use of some crucial pluripotency markers such as SSEA-3 and SSEA-4 has recently been questioned due to the possibility that the pattern of surface glycans may be changed depending on the content of the cell culture medium. Aim: Quantitative analysis of amniotic SC subpopulations cultured in different media, based on the following pluripotency surface markers: SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81 expression and co-expression. Material and methods: Immunofluorescence and fluorescence microscopy were used to identify and localize S.C. within a normal human placenta at term. The number of SSEA-4+, SSEA-3+, TRA-1-60+ and TRA-1-81+ cells and cells with co-expression of the above mentioned markers, cultured in media containing different protein supplements of animal origin, was counted by flow cytometry. Results and conclusions: Cells with characteristics of embryonic SC were identified in the amniotic epithelium and the chorion, but not in the decidua basalis. Amniotic epithelium contained various types of SC, with SSEA-4+ as the most numerous. Disproportion in the number of SSEA-4+, SSEA-3+, TRA-1-60+ and TRA-1-81+ cells and cells characterized by co-expression of these antigens, as well as lack of quantitative differences between S.C. subpopulations cultured in different media, was observed. In conclusion, the amniotic epithelium is composed of SC at different stages of the development but human amnion might become an alternative source of SSEA-4+ embryonic-like SC. The composition of the evaluated media, characterized by different content of animal-derived proteins, does not influence the number of cells identified within the SC subpopulations

Polymorphisms in DNA repair genes – assessment of frequencies and effect on the level of DNA oxidative damage caused by lead

Introduction. The aim of this study was to evaluate the effect of polymorphisms in DNA repair genes: APE1, hOGG1, XRCC1, XPA on the level of oxidative damage to DNA as well as an assessment of the frequencies of genetic polymorphisms in the adult population of Caucasians from southern Poland. Material and methods. We examined a group of 115 men occupationally exposed to lead and 58 men with no history of occupational exposure to lead. The concentrations of lead in blood, zinc protoporphyrin in blood and 8-hydroxy-2-deoxyguanosine in urine were measured. The identification of SNP polymorphisms in genes encoding enzymes involved in DNA repair (APEX1, hOGG1, XPA, XRCC1) was performed using real-time PCR with TaqMan probes. We analyzed polymorphisms: APEX1 (rs1130409, Asp148Glu), hOGG1 (rs1052133, Ser326Cys), XPA (rs1800975, -4A/G) and XRCC1 (rs25487, Gln399Arg). Results. The mean blood lead level in the exposed group was 33,48 μg/dl and was significantly higher compared to 5.35 μg/dl (p=0.000). in the control group. The frequencies of studied polymorphisms were comparable in both groups, with the exception of -4A/G (rs1800975) in the gene XPA (p<0.0001). Conclusions. Differences were observed between genotypes in -4A/G (rs1800975) polymorphism in relations to the level of lead in blood (p=0.006) and Ser326Cys (rs1052133) polymorphism in relations to 8-hydroxy-2- deoxyguanosine in urine (p=0.01).Wstęp. Celem pracy była ocena wpływu polimorfizmów w genach naprawy DNA: APE1, hOGG1, XRCC1, XPA na poziom uszkodzeń oksydacyjnych w DNA oraz ocena częstości ich występowania w populacji dorosłych osób rasy kaukaskiej pochodzących z południowej Polski. Materiał i metody. Przebadano grupę 115 mężczyzn narażonych zawodowo na ołów oraz 58 mężczyzn bez narażenia na ołów w wywiadzie, którzy stanowili grupę kontrolną. U wszystkich osób oznaczono poziom ołowiu we krwi, cynkoprotoporfiryny, oraz stężenie 8-hydroksy- 2-deoksyguanozyny w moczu. Identyfikację polimorfizmów typu SNP w genach kodujących enzymy biorące udział w naprawie DNA (APEX1, hOGG1, XPA, XRCC1) przeprowadzono z wykorzystaniem metody real-time PCR z sondami TaqMan. Analizie poddano polimorfizmy w genach APEX1 (rs1130409, Asp148Glu), hOGG1 (rs1052133, Ser326Cys), XPA (rs1800975, -4A/G) oraz XRCC1 (rs25487, Gln399Arg). Wyniki. Średni poziom ołowiu we krwi w grupie badanej wynosił 33,48 μg/dl i był istotnie statystycznie wyższy niż w grupie kontrolnej, gdzie wynosił 5,35 μg/dl (p=0,000). Częstość występowania poszczególnych genotypów badanych polimorfizmów była porównywalna w obu grupach, z wyjątkiem polimorfizmu -4A/G (rs1800975) w genie XPA (p<0,0001). Wnioski. Zaobserwowano różnice pomiędzy poszczególnymi genotypami w polimorfizmie -4A/G (rs1800975) w odniesieniu do poziomu ołowiu we krwi (p=0,006) oraz w polimorfizmie Ser326Cys (rs1052133) w odniesieniu do poziomu 8-hydroksy-2-deoksyguanozyny w moczu (p=0,01)

Synthesis, Characterization and Cytotoxicity of Novel Thermoresponsive Star Copolymers of <i>N</i>,<i>N</i>′-Dimethylaminoethyl Methacrylate and Hydroxyl-Bearing Oligo(Ethylene Glycol) Methacrylate

Novel, nontoxic star copolymers of N,N-dimethylaminoethyl methacrylate (DMAEMA) and hydroxyl-bearing oligo(ethylene glycol) methacrylate (OEGMA-OH) were synthesized via atom transfer radical polymerization (ATRP) using hyperbranched poly(arylene oxindole) as the macroinitiator. Stars with molar masses from 100,000 g/mol to 257,000 g/mol and with various amounts of OEGMA-OH in the arms were prepared. As these polymers can find applications, e.g., as carriers of nucleic acids, drugs or antibacterial or antifouling agents, in this work, much attention has been devoted to exploring their solution behavior and their stimuli-responsive properties. The behavior of the stars was studied in aqueous solutions under various pH and temperature conditions, as well as in PBS buffer, in Dulbecco&#8217;s modified Eagle&#8217;s medium (DMEM) and in organic solvents for comparison. The results indicated that increasing the content of hydrophilic OEGMA-OH units in the arms up to 10 mol% increased the cloud point temperature. For the stars with an OEGMA-OH content of 10 mol%, the thermo- and pH-responsivity was switched off. Since cytotoxicity experiments have shown that the obtained stars are less toxic than homopolymer DMAEMA stars, the presented studies confirmed that the prepared polymers are great candidates for the design of various nanosystems for biomedical applications