Recently, the United States Suoerke Biology Institute for the first time scientists successfully developed a human chimerism embryos, related papers published in the "cell" magazine. Human and animal chimeric embryos will help mimic the early onset of many human genetic diseases and carry out drug testing. At present, the new pig chimera is helping scientists understand the human stem cell growth and differentiation.
"The ultimate goal of this study is to produce transplantable human cells, tissues and organs in animals, but we are still a long way from this," said Juan Carlos Izpisua Belmonte, head of the study. "In any case, this is stem cell research A milestone in the field, we have taken an important first step. "
In this study, Izpisua Belmonte and colleague Wu Jun used the "gene scissors" CRISPR technique to remove key genes that form organs in pig embryos, creating a genetic "gap." Researchers then injected human induced pluripotent stem cells into porcine embryos. Induced pluripotent stem cells are directly derived from human somatic cells and have the ability to differentiate into various types of cells as embryonic stem cells.
The team will be human stem cells were implanted more than 1500 pig blastocyst. After implantation in pigs, these blastocysts developed from 21 days to 28 days, 186 of which survived, in which different states of induced pluripotent stem cells in the porcine embryo to form "varying degrees of chimerism." The stem cells were from 40 donors, including pig farmers.
Because the evolution of pigs and human distance, and the length of the animal is about 1/3 of the human, so the researchers need to inject human cells at the right time to match the developmental stages of pigs.
In addition, the researchers used three different states of human stem cells, namely the original primitive state, has developed but still differentiation potential of the initial state and in between the intermediate state, to test which cells can be better Survival. The results showed that the intermediate-state pluripotent stem cells were most suitable for chimerism, while the primitive state could not form chimera.
Moreover, in the chimera, the proportion of human cells is very low. Izpisua Belmonte says this is good news because a major concern about human chimeras is that it may be too human, including human cells, to influence the brain development of pigs.
In this study, human cells develop into precursor cells of muscle cells and other tissues and organs, rather than precursor cells of brain cells. "Now we want to know whether yes or no, the question is whether human cells can contribute." Now that we have the answer to 'yes', the next challenge is to improve efficiency and guide human cells to form specific organs in the pig. "Izpisua Belmonte said.
prev:Zhang Xu and so reveal the nociceptive heat stimulation of the key regulatory mechanism of pain(2017-02-07)
next:A New Concept of "Synthetic Necessary"(2017-02-08)