Animal Models - GEG Tech top picks

Australia has approved the use of CRISPR gene editing tool on plants and animals without the oversight of a governmental body. The controversial move has been called a 'middle ground' compared to regulations on other countries.

For the first time, scientists have performed prenatal gene editing to prevent a lethal metabolic disorder in laboratory animals, offering the potential to treat human congenital diseases before birth. Published today in Nature Medicine, research from Children’s Hospital of Philadelphia (CHOP) and the Perelman School of Medicine at the University of Pennsylvania offers proof-of-concept for prenatal use of a sophisticated, low-toxicity tool that efficiently edits DNA building blocks in disease-causing genes.

OHSU scientists have discovered a naturally occurring disease in monkeys that mimics a deadly childhood neurodegenerative disorder in people – a finding that holds promise for developing new gene therapies to treat Batten disease.

In the present study, the CRISPR/Cas system was used to target the Tph2 gene in Bama mini pig fetal fibroblasts. It was found that CRISPR/Cas9 targeting efficiency could be as high as 61.5%, and the biallelic mutation efficiency reached at 38.5%. The biallelic modified colonies were used as donors for somatic cell nuclear transfer (SCNT) and 10 Tph2 targeted piglets were successfully generated. These Tph2 KO piglets were viable and appeared normal at the birth. However, their central 5-HT levels were dramatically reduced, and their survival and growth rates were impaired before weaning. These Tph2 KO pigs are valuable large-animal models for studies of 5-HT deficiency induced behavior abnomality.

Here, the scientists describe the generation of transgenic, inducible CRISPR-based mouse systems to engineer and study recurrent colon cancer-associated EIF3E-RSPO2 and PTPRK-RSPO3 chromosome rearrangements in vivo. 

Genome editing for spermatogonial stem cells (SSCs) still remains a big challenge mainly due to low efficiency and complexity of currently available techniques. T

Here the authors describe CRISPR-Cas9-mediated gene editing via nonhomologous end joining (NHEJ) or homology-directed repair (HDR) in SSCs. This protocol provides guidelines for derivation of SSCs, nucleofection of SSCs with the CRISPR-Cas9 system, transplantation of the gene-modified SSCs into the recipient testes, and production of mice using transplanted SSC-derived round spermatids.

The microinjection of mouse oocytes is commonly used for both classic transgenesis (i.e., the random integration of transgenes) and CRISPR-mediated gene targeting. This protocol reviews the latest developments in microinjection, with a particular emphasis on quality control and genotyping strategies.

Pig-primate chimeras have been born live for the first time but died within a week. The two piglets, created by a team in China, looked normal although a small proportion of their cells were derived from cynomolgus monkeys.

“This is the first report of full-term pig-monkey chimeras,” says Tang Hai at the State Key Laboratory of Stem Cell and Reproductive Biology in Beijing.

Read more: https://link.springer.com/article/10.1007%2Fs13238-019-00676-8

Biologists have embraced CRISPR’s ability to quickly and cheaply modify the genomes of popular model organisms, such as mice, fruit flies and monkeys. Now they are trying the tool on more-exotic species, many of which have never been reared in a lab or had their genomes analysed. “We finally are ready to start expanding what we call a model organism,” says Tessa Montague, a molecular biologist at Columbia University in New York City. 

But the practical challenges of breeding and maintaining unconventional lab animals persist.

Researchers have developed a comprehensive way to evaluate how immune responses of humanized mice measure up to actual humans.

 Findings from the new study were published recently in Nature Communications through an article titled “Selective expansion of myeloid and NK cells in humanized mice yields human-like vaccine responses.”

On Wednesday, researchers from University of Texas Medical Branch published a new paper in the journal Science Translational Medicine.

In it, they detail their latest milestone along the path to creating lab-grown lungs for humans: they can now successfully transplant these bioengineered lungs into pigs.

Knock-in mice with precise insertions are efficiently generated through delivery of CRISPR–Cas9 to two-cell embryos.

The present work demonstrates that multiplex embryo transfer and multiplex gene targeting can be used to quickly and efficiently generate mutant rabbit founders. Four lines of SGM (e.g. FOXN1, RAG2, IL2RG, and PRKDC) immunodeficient rabbits, as well as multigenic mutant immunodeficient rabbits have been produced. These animals may prove useful for biomedical research.

Xenotransplantation is a promising strategy to alleviate the shortage of organs for human transplantation.

Here, the scientists confirmed the risk of cross-species transmission of porcine endogenous retroviruses (PERVs), and observed the horizontal transfer of PERVs among human cells. Using CRISPR-Cas9, they inactivated all the PERVs in a porcine primary cell line and generated PERV-inactivated pigs via somatic cell nuclear transfer. This study highlighted the value of PERV inactivation to prevent cross-species viral transmission and demonstrated the successful production of PERV-inactivated animals to address the safety concern in clinical xenotransplantation.

In the present study, The authors applied CRISPR/Cas9 system to target the C3 gene in porcine fetal fibroblasts. Their results indicated that CRISPR/Cas9 targeting efficiency was as high as 84.7%, and the biallelic mutation efficiency reached at 45.7%. The biallelic modified colonies were used as donor for somatic cell nuclear transfer (SCNT) technology to generate C3 targeted piglets. A total of 19 C3 knockout (KO) piglets were produced and their plasma C3 protein was undetectable by western blot analysis and ELISA. 

Modeling human disease has proven to be a challenge for the scientific community. For years, generating an animal model was complicated and restricted to very few species. With the rise of CRISPR/Cas9, it is now possible to generate more or less any animal model. In this review, we will show how this technology is and will change our way to obtain relevant disease animal models and how it should impact human health.