Application and perspective of CRISPR/Cas9 genome editing technology in human diseases modeling and gene therapy.

The Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) mediated Cas9 nuclease system has been extensively used for genome editing and gene modification in eukaryotic cells. CRISPR/Cas9 technology holds great potential for various applications, including the correction of genetic defects or mutations within the human genome. The application of CRISPR/Cas9 genome editing system in human disease research is anticipated to solve a multitude of intricate molecular biology challenges encountered in life science research. Here, we review the fundamental principles underlying CRISPR/Cas9 technology and its recent application in neurodegenerative diseases, cardiovascular diseases, autoimmune related diseases, and cancer, focusing on the disease modeling and gene therapy potential of CRISPR/Cas9 in these diseases. Finally, we provide an overview of the limitations and future prospects associated with employing CRISPR/Cas9 technology for diseases study and treatment.

Derivation of Porcine Extra-Embryonic Endoderm Cell Lines Reveals Distinct Signaling Pathway and Multipotency States.

The inner cell mass of the pre-implantation blastocyst consists of the epiblast and hypoblast from which embryonic stem cells (ESCs) and extra-embryonic endoderm (XEN) stem cells, respectively, can be derived. Importantly, each stem cell type retains the defining properties and lineage restriction of its in vivo tissue origin. We have developed a novel approach for deriving porcine XEN (pXEN) cells via culturing the blastocysts with a chemical cocktail culture system. The pXEN cells were positive for XEN markers, including Gata4, Gata6, Sox17, and Sall4, but not for pluripotent markers Oct4, Sox2, and Nanog. The pXEN cells also retained the ability to undergo visceral endoderm (VE) and parietal endoderm (PE) differentiation in vitro. The maintenance of pXEN required FGF/MEK+TGFß signaling pathways. The pXEN cells showed a stable phenotype through more than 50 passages in culture and could be established repeatedly from blastocysts or converted from the naïve-like ESCs established in our lab. These cells provide a new tool for exploring the pathways of porcine embryo development and differentiation and providing further reference to the establishment of porcine ESCs with potency of germline chimerism and gamete development.

Saponin from Tupistra chinensis Bak Inhibits NF-κB Signaling in Sarcoma S-180 Cell Mouse Xenografts.

This study examined the effect of saponins from Tupistra chinensis Bak (STCB) on the growth of sarcoma S-180 cells in vitro and in mouse xenografts as well as the underlying mechanisms. Cell proliferation was assessed by MTT assay. Cell cycle distribution was determined by flow cytometry. Sarcoma S-180 tumor-bearing mice were treated with different doses of STCB with 10 µg/mL 5-fluorouracil (5-Fu) as a positive control. The activity of nuclear factor (NF)-κB was detected by gel mobility shift assay. The mRNA level of NF-κB was determined by real-time quantitative RT-PCR. The results showed that in vitro STCB inhibited the growth of S-180 cells in a concentration-dependent manner, which was accompanied by cell cycle arrest at S-phase. In vivo STCB significantly inhibited the growth of S-180 tumor mouse xenografts in a dose-dependent manner with apparent induction of cell apoptosis. Moreover, STCB inhibited the activity of NF-κB p65 and reduced the expression of NF-κB p65 mRNA in mouse xenografts. It was concluded that STCB inhibits the proliferation and cell cycle progression of S-180 cells by suppressing NF-κB signaling in mouse xenografts. Our findings suggest STCB is a promising agent for the treatment of sarcoma.

Generation of tryptophan hydroxylase 2 gene knockout pigs by CRISPR/Cas9-mediated gene targeting.

Unbalanced brain serotonin (5-HT) levels have implications in various behavioral abnormalities and neuropsychiatric disorders. The biosynthesis of neuronal 5-HT is regulated by the rate-limiting enzyme, tryptophan hydroxylase-2 (TPH2). In the present study, the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) system was used to target theTph2 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 10Tph2 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. TheseTph2 KO pigs are valuable large-animal models for studies of 5-HT deficiency induced behavior abnomality.

Derivation of Porcine Embryonic Stem-Like Cells from In Vitro-Produced Blastocyst-Stage Embryos.

Efficient isolation of embryonic stem (ES) cells from pre-implantation porcine embryos has remained a challenge. Here, we describe the derivation of porcine embryonic stem-like cells (pESLCs) by seeding the isolated inner cell mass (ICM) from in vitro-produced porcine blastocyst into α-MEM with basic fibroblast growth factor (bFGF). The pESL cells kept the normal karyotype and displayed flatten clones, similar in phenotype to human embryonic stem cells (hES cells) and rodent epiblast stem cells. These cells exhibited alkaline phosphatase (AP) activity and expressed pluripotency markers such as OCT4, NANOG, SOX2, SSEA-4, TRA-1-60, and TRA-1-81 as determined by both immunofluorescence and RT-PCR. Additionally, these cells formed embryoid body (EB), teratomas and also differentiated into 3 germ layers in vitro and in vivo. Microarray analysis showed the expression of the pluripotency markers, PODXL, REX1, SOX2, KLF5 and NR6A1, was significantly higher compared with porcine embryonic fibroblasts (PEF), but expression of OCT4, TBX3, REX1, LIN28A and DPPA5, was lower compared to the whole blastocysts or ICM of blastocyst. Our results showed that porcine embryonic stem-like cells can be established from in vitro-produced blastocyst-stage embryos, which promote porcine naive ES cells to be established.