Single base editing system mediates site-directed mutagenesis of genes GDF9 and FecB in Ouler Tibetan sheep / 生物工程学报

In this study, a single base editing system was used to edit the FecB and GDF9 gene to achieve a targeted site mutation from A to G and from C to T in Ouler Tibetan sheep fibroblasts, and to test its editing efficiency. Firstly, we designed and synthesized sgRNA sequences targeting FecB and GDF9 genes of Ouler Tibetan sheep, followed by connection to epi-ABEmax and epi-BE4max plasmids to construct vectors and electrotransfer into Ouler Tibetan sheep fibroblasts. Finally, Sanger sequencing was performed to identify the target point mutation of FecB and GDF9 genes positive cells. T-A cloning was used to estimate the editing efficiency of the single base editing system. We obtained gRNA targeting FecB and GDF9 genes and constructed the vector aiming at mutating single base of FecB and GDF9 genes in Ouler Tibetan sheep. The editing efficiency for the target site of FecB gene was 39.13%, whereas the editing efficiency for the target sites (G260, G721 and G1184) of GDF9 gene were 10.52%, 26.67% and 8.00%, respectively. Achieving single base mutation in FecB and GDF9 genes may facilitate improving the reproduction traits of Ouler Tibetan sheep with multifetal lambs.

knocking out mediated by CRISPR-Cas9 genome editing for PD-L1 attenuation and enhanced antitumor immunity

Blocking the programmed death-ligand 1 (PD-L1) on tumor cells with monoclonal antibody therapy has emerged as powerful weapon in cancer immunotherapy. However, only a minority of patients presented immune responses in clinical trials. To develop an alternative treatment method based on immune checkpoint blockade, we designed a novel and efficient CRISPR-Cas9 genome editing system delivered by cationic copolymer aPBAE to downregulate PD-L1 expression on tumor cells specifically knocking out Cyclin-dependent kinase 5 () gene . The expression of PD-L1 on tumor cells was significantly attenuated by knocking out , leading to effective tumor growth inhibition in murine melanoma and lung metastasis suppression in triple-negative breast cancer. Importantly, we demonstrated that aPBAE/Cas9-Cdk5 treatment elicited strong T cell-mediated immune responses in tumor microenvironment that the population of CD8 T cells was significantly increased while regulatory T cells (Tregs) was decreased. It may be the first case to exhibit direct PD-L1 downregulation CRISPR-Cas9 genome editing technology for cancer therapy. It will provide promising strategy for preclinical antitumor treatment through the combination of nanotechnology and genome engineering.

Improving Scientific Writing Skills and Publishing Capacity by Developing University-Based Editing System and Writing Programs

Scholarly article writing and publishing in international peer-reviewed journals can become an overwhelming task for many medical, nursing, and healthcare professionals in a university setting, especially in countries whose native language is not English. To help improve their scientific writing skills and publishing capacity, a university-based editing system and writing programs can be developed as educational platforms. These are delivered by a team of specialist editors composed of tenured faculty members who have a strong medical background and extensive experience in teaching courses on medical research, editing, writing, and publishing. For the editing system, the specialist editors provide comprehensive editing, personalized consultation, full editorial support after peer review, guidance with online submissions/resubmissions, and detailed editorial review at different stages of the manuscript writing. In addition, the specialist editors can develop writing programs such as medical writing and editing internships, academic courses in medical writing or research study designs and reporting standards, special interactive lectures and sessions on predatory publishing, seminars on updated editorial guidance of global editorial associations, academic visits on medical writing and editing, medical writing mentoring program, networking programs in scholarly communication, and publication resources in medical writing and scholarly publishing. These editing system and writing programs can serve as integrated platforms for improving scientific writing skills and publishing capacity by providing continuing education in medical writing, editing, publishing, and publication ethics.