Functional disruption of human leukocyte antigen II in human embryonic stem cell

BACKGROUND: Theoretically human embryonic stem cells (hESCs) have the capacity to self-renew and differentiate into all human cell types. Therefore, the greatest promise of hESCs-based therapy is to replace the damaged tissues of patients suffering from traumatic or degenerative diseases by the exact same type of cells derived from hESCs. Allo-graft immune rejection is one of the obstacles for hESCs-based clinical applications. Human leukocyte antigen (HLA) II leads to CD4+ T cells-mediated allograft rejection. Hence, we focus on optimizing hESCs for clinic application through gene modification. RESULTS: Transcription activator-like effector nucleases (TALENs) were used to target MHC class II transactivator (CIITA) in hESCs efficiently. CIITA(-/-)hESCs did not show any difference in the differentiation potential and self-renewal capacity. Dendritic cells (DCs) derived from CIITA(-/-)hESCs expressed CD83 and CD86 but without the constitutive HLA II. Fibroblasts derived from CIITA(-/-)hESCs were powerless in IFN-γ inducible expression of HLA II. CONCLUSION: We generated HLA II defected hESCs via deleting CIITA, a master regulator of constitutive and IFN-γ inducible expression of HLA II genes. CIITA(-/-)hESCs can differentiate into tissue cells with non-HLA II expression. It's promising that CIITA(-/-)hESCs-derived cells could be used in cell therapy (e.g., T cells and DCs) and escape the attack of receptors' CD4+ T cells, which are the main effector cells of cellular immunity in allograft.

Reflexoes sobre a investigacao em embrioes de origem humana: o debate nas organizacoes de etica portuguesas / Reflections on human embryo research: the debate in Portuguese ethics organizations

Analisam-se os argumentos usados pelas organizações de ética portuguesas na regulação da investigação em embriões de origem humana. Recolheram-se documentos produzidos entre 2006 e 2010. Procedeu-se à análise temática de conteúdo, e as estratégias discursivas foram estudadas a partir de uma abordagem semântica da informação. Discutiram-se o estatuto do embrião abstrato (ser humano/pessoa ou artefato biológico/neoestrutura laboratorial) e os critérios que devem nortear as boas práticas e equilibrar expectativas e riscos na investigação em embriões, coexistindo argumentos heterogéneos oriundos da bioética principialista, laica e interventiva. Importa incorporar no debate as perspetivas de quem tem que decidir o destino de embriões concretos.

This article analyzes the arguments used by Portuguese ethics organizations on to the regulation of human embryo research. Documents produced between 2006 and 2010 were collected and, based on thematic content analysis, the discursive strategies were studied from a semantic approach to data. The debate focused the status of abstract embryos (human being/person or biological artifact/laboratory neostructure) and the criteria that should guide best practices and balance expectations and risks on embryo research, in which heterogeneous arguments coexist based on principialist, secular and interventional bioethics. The perspectives of those who must decide the fate of real embryos should be incorporated into the discussion.

Transcriptional activity of the 5'-flanking region of the thyroid transcription factor-1 gene in human thyroid cell lines

Thyroid transcription factor-1 (TTF-1, NKX2-1) is a homeodomain-containing transcriptional factor that binds to and activates the promoters of thyroid and lung-specific genes, such as thyroglobulin, thyroid peroxidase, and thyroid stimulating hormone receptor. TTF-1 is known to play a key role in the development of the thyroid. However, the precise mechanism of TTF-1 gene transcription in human thyroid cells has not been studied. The expression of transcriptional activity in various lengths of the 5'-flanking region of the human TTF -1 gene was studied in TTF-1 positive and negative human thyroid cell lines. Increased transcriptional activity was observed in thyroid cell lines containing plasmids that coded for a sequence proximal to the transcription start site of exon 1 of the TTF-1 gene. However, we did not observe any difference in promoter activity in the region up to -2.6 kb from the proximal transcription start site of the TTF-1 gene between TTF-1 positive and negative cells. These results suggest that the proximal 5'-flanking region of the human TTF -1 gene does not contain sufficient cis-active regulatory information to direct gene expression in thyroid cells,and that other cis-or trans-acting factors participate in the thyroid specific gene expression of TTF-1.