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Application of genetics and biotechnology for improving medicinal plants.
Plant tissue culture has been used for conservation, micropropagation, and in planta overproduction of some pharma molecules of medicinal plants. New biotechnology-based breeding methods such as targeted genome editing methods are able to create custom-designed medicinal plants with different secondary metabolite profiles. For a long time, humans have used medicinal plants for therapeutic purposes and in food and other industries. Classical biotechnology techniques have been exploited in breeding medicinal plants. Now, it is time to apply faster biotechnology-based breeding methods (BBBMs) to these valuable plants. Assessment of the genetic diversity, conservation, proliferation, and overproduction are the main ways by which genetics and biotechnology can help to improve medicinal plants faster. Plant tissue culture (PTC) plays an important role as a platform to apply other BBBMs in medicinal plants. Agrobacterium-mediated gene transformation and artificial polyploidy induction are the main BBBMs that are directly dependent on PTC. Manageable regulation of endogens and/or transferred genes via engineered zinc-finger proteins or transcription activator-like effectors can help targeted manipulation of secondary metabolite pathways in medicinal plants. The next-generation sequencing techniques have great potential to study the genetic diversity of medicinal plants through restriction-site-associated DNA sequencing (RAD-seq) technique and also to identify the genes and enzymes that are involved in the biosynthetic pathway of secondary metabolites through precise transcriptome profiling (RNA-seq). The sequence-specific nucleases of transcription activator-like effector nucleases (TALENs), zinc-finger nucleases, and clustered regularly interspaced short palindromic repeats-associated (Cas) are the genome editing methods that can produce user-designed medicinal plants. These current targeted genome editing methods are able to manage plant synthetic biology and open new gates to medicinal plants to be introduced into appropriate industries.
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DNA methylation defines regional identity of human intestinal epithelial organoids and undergoes dynamic changes during development.
OBJECTIVE: Human intestinal epithelial organoids (IEOs) are increasingly being recognised as a highly promising translational research tool. However, our understanding of their epigenetic molecular characteristics and behaviour in culture remains limited. DESIGN: We performed genome-wide DNA methylation and transcriptomic profiling of human IEOs derived from paediatric/adult and fetal small and large bowel as well as matching purified human gut epithelium. Furthermore, organoids were subjected to in vitro differentiation and genome editing using CRISPR/Cas9 technology. RESULTS: We discovered stable epigenetic signatures which define regional differences in gut epithelial function, including induction of segment-specific genes during cellular differentiation. Established DNA methylation profiles were independent of cellular environment since organoids retained their regional DNA methylation over prolonged culture periods. In contrast to paediatric and adult organoids, fetal gut-derived organoids showed distinct dynamic changes of DNA methylation and gene expression in culture, indicative of an in vitro maturation. By applying CRISPR/Cas9 genome editing to fetal organoids, we demonstrate that this process is partly regulated by TET1, an enzyme involved in the DNA demethylation process. Lastly, generating IEOs from a child diagnosed with gastric heterotopia revealed persistent and distinct disease-associated DNA methylation differences, highlighting the use of organoids as disease-specific research models. CONCLUSIONS: Our study demonstrates striking similarities of epigenetic signatures in mucosa-derived IEOs with matching primary epithelium. Moreover, these results suggest that intestinal stem cell-intrinsic DNA methylation patterns establish and maintain regional gut specification and are involved in early epithelial development and disease.
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A Review on Advanced CRISPR-Based Genome-Editing Tools: Base Editing and Prime Editing.
In the field of medicine, it is axiomatic that the need of a precise gene-editing tool is critical to employ therapeutic approaches toward pathogenic mutations, occurring in human genome. Today we know that most of genetic defects are caused by single-base pair substitutions in genomic DNA. The ability to make practically any targeted substitutions of DNA sequences at specified regions in the human genome gives us the chance to employ gene therapy in most known diseases associated with genetic variants. In this regard, CRISPR/Cas9 applications is becoming more and more popular along with the significant advancements of life sciences, by employing this technology in genome-editing and high-throughput screenings. Several CRISPR/Cas-based mammalian cell gene-editing techniques have been developed during the last decade, including nucleases, base editors, and prime editors, all of which have the exact mechanism at first glance. However, they address a subset of known pathogenic sequence mutations using different methods. First, we highlight the development of CRISPR-based gene-editing tools. Then we describe their functions and summarize the conducted research studies, which are increasing the reliability of these strategies to better efficiencies for prospective gene therapies in the near future. Lastly, we compare the capabilities of all these platforms together besides their probable limitations.
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Research progress in gene editing technology.
As a tool for modifying the genome, gene editing technology has developed rapidly in recent years, especially in the past two years. With the emergence of new gene editing technologies, such as transposon editing tools, numerous advancements have been made including precise editing of the genome, double base editing, and pilot editing. This report focuses on the development of gene editing tools in recent years, elaborates the progress made in classic editing tools, base editor and other new editing tools, and provides insights into challenges and opportunities.
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Leveraging a natural murine meiotic drive to suppress invasive populations.
Invasive rodents are a major cause of environmental damage and biodiversity loss, particularly on islands. Unlike insects, genetic biocontrol strategies including population-suppressing gene drives with biased inheritance have not been developed in mice. Here, we demonstrate a gene drive strategy (tCRISPR) that leverages super-Mendelian transmission of the t haplotype to spread inactivating mutations in a haplosufficient female fertility gene (Prl). Using spatially explicit individual-based in silico modeling, we show that tCRISPR can eradicate island populations under a range of realistic field-based parameter values. We also engineer transgenic tCRISPR mice that, crucially, exhibit biased transmission of the modified t haplotype and Prl mutations at levels our modeling predicts would be sufficient for eradication. This is an example of a feasible gene drive system for invasive alien rodent population control.
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Enhanced NK-92 Cytotoxicity by CRISPR Genome Engineering Using Cas9 Ribonucleoproteins.
Natural killer (NK) cells are an attractive cell-type for adoptive immunotherapy, but challenges in preparation of therapeutic primary NK cells restrict patient accessibility to NK cell immunotherapy. NK-92 is a well-characterized human NK cell line that has demonstrated promising anti-cancer activities in clinical trials. Unlimited proliferation of NK-92 cells provides a consistent supply of cells for the administration and development of NK cell immunotherapy. However, the clinical efficacy of NK-92 cells has not reached its full potential due to reduced immune functions as compared to primary NK cells. Improvements of NK-92 functions currently rely on conventional transgene delivery by mRNA, plasmid and viral vector with limited efficiencies. To enable precise genetic modifications, we have established a robust CRISPR genome engineering platform for NK-92 based on the nucleofection of Cas9 ribonucleoprotein. To demonstrate the versatility of the platform, we have performed cell-based screening of Cas9 guide RNA, multiplex gene knockout of activating and inhibitory receptors, knock-in of a fluorescent gene, and promoter insertion to reactivate endogenous CD16 and DNAM-1. The CRISPR-engineered NK-92 demonstrated markedly enhanced cytotoxicity and could mediate antibody-dependent cellular cytotoxicity against hard to kill cancer cell lines. Our genome editing platform is straightforward and robust for both functional studies and therapeutic engineering of NK-92 cells.
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CRISPR-Cas9-modified pfmdr1 protects Plasmodium falciparum asexual blood stages and gametocytes against a class of piperazine-containing compounds but potentiates artemisinin-based combination therapy partner drugs.
Emerging resistance to first-line antimalarial combination therapies threatens malaria treatment and the global elimination campaign. Improved therapeutic strategies are required to protect existing drugs and enhance treatment efficacy. We report that the piperazine-containing compound ACT-451840 exhibits single-digit nanomolar inhibition of the Plasmodium falciparum asexual blood stages and transmissible gametocyte forms. Genome sequence analyses of in vitro-derived ACT-451840-resistant parasites revealed single nucleotide polymorphisms in pfmdr1, which encodes a digestive vacuole membrane-bound ATP-binding cassette transporter known to alter P. falciparum susceptibility to multiple first-line antimalarials. CRISPR-Cas9 based gene editing confirmed that PfMDR1 point mutations mediated ACT-451840 resistance. Resistant parasites demonstrated increased susceptibility to the clinical drugs lumefantrine, mefloquine, quinine and amodiaquine. Stage V gametocytes harboring Cas9-introduced pfmdr1 mutations also acquired ACT-451840 resistance. These findings reveal that PfMDR1 mutations can impart resistance to compounds active against asexual blood stages and mature gametocytes. Exploiting PfMDR1 resistance mechanisms provides new opportunities for developing disease-relieving and transmission-blocking antimalarials.
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CRISPR/Cas9 Technology for Modifying Immune Checkpoint in CAR-T Cell Therapy for Hematopoietic Malignancies.
Hematologic malignancies, which arise from dysregulation of hematopoiesis, are a group of cancers originating in cells with diminished capacity to differentiate into mature progeny and accumulating immature cells in blood-forming tissues such as lymph nodes and bone marrow. Immune- targeted therapies, such as Immune Checkpoint Blockade (ICB), chimeric antigen receptor T (CAR-T) cell therapy, and the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) system, a precise, popular, and versatile genome engineering tool, has opened new avenues for the treatment of malignancies. Targeting immune checkpoints has revolutionized FDA approval in cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), PD-1 (programmed death-1), and PDL1. According to the ICB and CAR techniques, the production of efficient CAR-T cells depends on the successful genetic modification of T cells, making them less susceptible to immune escape and suppression by cancer cells, which results in reduced off-target toxicity. Therefore, CRISPR/Cas9 has revolutionized the immune checkpoint-based approach for CAR-T cell therapy of hematologic malignancy. Continued research and clinical trials will undoubtedly pave the way for further advances in this field, ultimately benefiting patients and improving outcomes.
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CBLB ablation with CRISPR/Cas9 enhances cytotoxicity of human placental stem cell-derived NK cells for cancer immunotherapy.
BACKGROUND: Tumors often develop resistance to surveillance by endogenous immune cells, which include natural killer (NK) cells. Ex vivo activated and/or expanded NK cells demonstrate cytotoxicity against various tumor cells and are promising therapeutics for adoptive cancer immunotherapy. Genetic modification can further enhance NK effector cell activity or activation sensitization. Here, we evaluated the effect of the genetic deletion of ubiquitin ligase Casitas B-lineage lymphoma pro-oncogene-b (CBLB), a negative regulator of lymphocyte activity, on placental CD34+ cell-derived NK (PNK) cell cytotoxicity against tumor cells. METHODS: Using CRISPR/Cas9 technology, CBLB was knocked out in placenta-derived CD34+ hematopoietic stem cells, followed by differentiation into PNK cells. Cell expansion, phenotype and cytotoxicity against tumor cells were characterized in vitro. The antitumor efficacy of CBLB knockout (KO) PNK cells was tested in an acute myeloid leukemia (HL-60) tumor model in NOD-scid IL2R gammanull (NSG) mice. PNK cell persistence, biodistribution, proliferation, phenotype and antitumor activity were evaluated. RESULTS: 94% of CBLB KO efficacy was achieved using CRISPR/Cas9 gene editing technology. CBLB KO placental CD34+ cells differentiated into PNK cells with high cell yield and >90% purity determined by CD56+ CD3- cell identity. Ablation of CBLB did not impact cell proliferation, NK cell differentiation or phenotypical characteristics of PNK cells. When compared with the unmodified PNK control, CBLB KO PNK cells exhibited higher cytotoxicity against a range of liquid and solid tumor cell lines in vitro. On infusion into busulfan-conditioned NSG mice, CBLB KO PNK cells showed in vivo proliferation and maturation as evidenced by increased expression of CD16, killer Ig-like receptors and NKG2A over 3 weeks. Additionally, CBLB KO PNK cells showed greater antitumor activity in a disseminated HL60-luciferase mouse model compared with unmodified PNK cells. CONCLUSION: CBLB ablation increased PNK cell effector function and proliferative capacity compared with non-modified PNK cells. These data suggest that targeting CBLB may offer therapeutic advantages via enhancing antitumor activities of NK cell therapies.
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Advances in base editing technology and the construction of precise zebrafish disease models.
Single nucleotide variants (SNVs) are among the primary pathogenic factors of human genetic diseases, accounting for a significant proportion of all mutation types. Conducting in-depth research on the pathogenic significance of these mutations in animal models is essential for understanding disease mechanisms and developing therapeutic strategies. The progress of such research largely depends on the continuous innovation and advancement of gene editing technologies. In recent years, base editing technology based on the CRISPR/Cas9 system has emerged, enabling precise conversion of individual nucleotides. Owing to its efficiency and convenience, base editing has been widely applied in gene therapy, the construction of animal models, and molecular breeding, bringing new breakthroughs and opportunities to life sciences and medical research. Zebrafish, with their advantages of small size, high fecundity, transparent embryos, and external development, have become an ideal model organism for studying disease mechanisms and drug screening. In this review, we summarize the development of CRISPR/Cas9-based base editing technologies, highlight the emergence of novel editing tools, and explore the application and progress of base editing in constructing precise zebrafish disease models.
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