CLAUDIA REGINA CECCHI

CLAUDIA REGINA CECCHI

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Assessment of the in vivo permanence of mGH-secreting human keratinocytes in grafted organotypic cultures
2009 - CECCHI, C.R.; OLIVEIRA, N.A.J.; HIGUTI, E.; NONOGAKI, S.; BOCCARDO, E.; BARTOLINI, P.; PERONI, C.N.
Electrotransfer of naked hGH cDNA muscle of lit/scid mouse is more efficient than genomic DNA
2009 - OLIVEIRA, N.A.J.; CECCHI, C.R.; HIGUTI, E.; MORISCOT, A.S.; BARTOLINI, P.; PERONI, C.N.
Sustained hGH expression after electrotransfer of naked DNA into DWARF 'little!' mouse skeletal muscle
2009 - OLIVEIRA, N.A.J.; CECCHI, C.R.; HIGUTI, E.; BARTOLINI, P.; PERONI, C.N.
High-level secretion of growth hormone by retrovirally transduced primary human keratinocytes: prospects for an animal model of cutaneous gene therapy
2005 - PERONI, C.N.; CECCHI, C.R.; DAMIANI, R.; SOARES, C.R.J.; RIBELA, M.T.C.P.; ARKATEN, R.R.; BARTOLINI, P.
Secrecao de hormonio de crescimento de camundongo por queratinocitos humanos primarios: perspectivas para um modelo animal de terapia genica cutanea
2008 - CECCHI, CLAUDIA R.
Queratinócitos são um veículo bastante atrativo para a transferência gênica ex vivo e liberação sistêmica uma vez que as proteínas secretadas por estas células podem atingir a circulação via um mecanismo similar ao processo natural. Um eficiente vetor retroviral (LXSN) contendo o gene do hormônio de crescimento de camundongo (mGH) foi utilizado para transduzir queratinócitos humanos primários. Os queratinócitos transduzidos apresentaram um nível de secreção in vitro alto e estável atingindo até 11 g mGH/106 células/dia. Os epitélios formados por estes queratinócitos geneticamente modificados apresentaram, porém, uma queda na taxa de secreção > 80 % quando foram retirados da placa de cultura utilizando um procedimento clássico. A substituição desta metodologia clássica por uma cultura organotípica resolveu completamente este problema. Camundongos anões imunodeficientes (lit/scid) implantados com estes enxertos organotípicos foram acompanhados durante 4 meses, e apresentaram um aumento de peso significativo (P<0,05) nos primeiros 40 dias. Níveis circulatórios de mGH atingiram um pico de 21 ng/mL 1 h após o implante, mas estes níveis rapidamente atingiram níveis basais (~2 ng/mL). Os queratinócitos humanos primários apresentaram portanto altos níveis de expressão in vitro e os maiores níveis circulatórios, porém por um breve período de tempo, reportados até o momento para GH neste tipo de células. Em conjunto com resultados que mostraram uma recuperação considerável da eficiência de secreção de mGH em cultura por enxertos organotípicos retirados dos animais, foram discutidos os fatores que ainda impedem a utilização clínica deste modelo promissor de terapia gênica cutânea.
Sustained hGH expression after electrotransfer of naked DNA into DWARF 'little!' mouse skeletal muscle
2009 - OLIVEIRA, NELIO A. de J.; CECCHI, CLAUDIA R.; HIGUTI, ELIZA; BARTOLINI, PAOLO; PERONI, CIBELE N.
High-level secretion of growth hormone by retrovirally transduced primary human keratinocytes
2006 - PERONI, CIBELE N.; CECCHI, CLAUDIA R.; DAMIANI, RENATA; SOARES, CARLOS R.J.; RIBELA, MARIA T.C.P.; ARKATEN, ROSANGELA R.; BARTOLINI, PAOLO
A gene therapy clinical trial for treatment of growth hormone (GH) deficiency has not been reached yet, but several strategies using different gene transfer methodologies and animal models have been developed and showed successful results. We have set up an ex vivo gene therapy protocol using primary human keratinocytes transduced with an efficient retroviral vector (LXSN) encoding the human (hGH) or mouse GH (mGH) genes. These stably modified cells presented high in vitro expression levels of hGH (7 μg/106 cells/d) and mGH (11 μg/106 cells/d) after selection with geneticin. When the hGH-secreting keratinocytes were grafted onto immunodeficient dwarf mice (lit/scid), hGH levels in the circulation were about 0.2–0.3 ng/mL during a 12-d assay and these animals presented a significant body weight increase (p<0.01) compared to the control. Substitution of conventional grafting methodologies with organotypic raft cultures revealed a peak value of up to 20 ng mGH/mL in the circulation of grafted lit/scid mice at 1 h postimplantation, followed by a rapid decline to baseline (≈2 ng/mL) within 24 h. One week after grafting, however, the cultured excised implants still presented approx 45% of their original in vitro secretion efficiency. Further studies are being carrier out to identify the main factor(s) that still constitute one of the major impediments to the success of this promising model of cutaneous gene therapy.
Secretion of mouse growth hormone by transduced primary human keratinocytes: prospects for an animal model of cutaneous gene therapy
2008 - PERONI, CIBELE N.; CECCHI, CLAUDIA R.; ROSAURO, CRISTIANE W.; NONOGAKI, SUELY; BOCCARDO, ENRIQUE; BARTOLINI, PAOLO
Background: Keratinocytes are a very attractive vehicle for ex vivo gene transfer and systemic delivery because proteins secreted by these cells may reach the circulation via a mechanism that mimics the natural process. Methods: An efficient retroviral vector (LXSN) encoding the mouse growth hormone gene (mGH) was used to transduce primary human keratinocytes. Organotypic raft cultures were prepared with these genetically modified keratinocytes and were grafted onto immunodeficient dwarf mice (lit/scid). Results: Transduced keratinocytes presented a high and stable in vitro secretion level of up to 11 µg mGH/106cells/day. Conventional epidermal sheets made with these genetically modified keratinocytes, however, showed a drop in secretion rates of > 80% due to detachment of the epithelium from its substratum. Substitution of conventional grafting methodologies with organotypic raft cultures completely overcame this problem. The stable long-term grafting of such cultures onto lit/scid mice could be followed for more than 4 months, and a significant weight increase over the control group was observed in the first 40 days. Circulating mGH levels revealed a peak of 21 ng/ml just 1 h after grafting but, unfortunately, these levels rapidly fell to baseline values. Conclusions: mGH-secreting primary human keratinocytes presented the highest in vitro expression and peak circulatory levels reported to date for a form of GH with this type of cells. Together with previous data showing that excised implants can recover a remarkable fraction of their original in vitro mGH secretion efficiency in culture, the factors that might still hamper the success of this promising model of cutaneous gene therapy are discussed.