Selected Grantee Publications
Prime Editing–Mediated Correction of the CFTR W1282X Mutation in iPSCs and Derived Airway Epithelial Cells
Li et al., PLOS ONE. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10686454/
Cystic fibrosis (CF) is caused by recessive mutations in the CF transmembrane conductance regulator (CFTR) gene. Correction of nonsense CFTR mutations, which affects 10% of CF patients, via genomic editing represents a promising therapeutic approach. In this study, investigators tested whether prime editing can be applied as a potential therapeutic modality. Induced pluripotent stem cells (iPSCs) from a CF patient homozygous for the CFTR W1282X mutation were used. Studies demonstrated that prime editing corrected mutant allele in iPSCs, which effectively restored CFTR function in iPSC-derived airway epithelial cells and organoids. Supported by ORIP (R01OD01026594).
Focused Ultrasound–Mediated Brain Genome Editing
Lao et al., PNAS. 2023.
https://www.pnas.org/doi/epdf/10.1073/pnas.2302910120
Gene editing in the brain has been challenging because of the restricted transport imposed by the blood–brain barrier (BBB). In this study, investigators described a safe and effective gene‑editing technique by using focused ultrasound (FUS) to transiently open the BBB for the transport of intravenously delivered CRISPR machinery to the brain in mice. By combining FUS with adeno-associated virus–mediated gene delivery, researchers can achieve more than 25% editing efficiency of particular cell types. This method has the potential to expand toolkit options for CRISPR delivery and opens opportunities for treating diseases of the brain, such as neurodegenerative disorders, with somatic genome editing. Supported by ORIP (U42OD026635) and NINDS.
Whole Genome Analysis for 163 gRNAs in Cas9-Edited Mice Reveals Minimal Off-Target Activity
Peterson et al., Communications Biology. 2023.
https://www.nature.com/articles/s42003-023-04974-0
CRISPR/Cas9 genome editing offers potential as a treatment for genetic diseases in humans. Using whole-genome sequencing, investigators assessed the occurrence of Streptococcus pyogenes Cas9–induced off-target mutagenesis in Cas9-edited founder mice. Sequencing and computational analysis indicate that the risk of Cas9 cutting at predicted off-target sites is lower than random genetic variation introduced into the genomes of inbred mice through mating. These findings will inform future design and use of Cas9-edited animal models and can provide context for evaluating off-target potential in genetically diverse patient populations. Supported by ORIP (UM1OD023221, UM1OD023222) and NHGRI.
Identification of a Heterogeneous and Dynamic Ciliome during Embryonic Development and Cell Differentiation
Elliott et al., Development. 2023.
Ciliopathies are a class of diseases that arise when the structure or function of the cilium is compromised. To definitively determine the extent of heterogeneity within the ciliome, investigators compared the ciliomes of six distinct embryonic domains. The data comprehensively revealed that about 30% of the ciliome is differentially expressed across analyzed tissues in the developing embryo. Furthermore, upregulation of numerous ciliary genes correlated with osteogenic cell-fate decisions, suggesting that changes in the ciliome contribute to distinct functions of cell types in vertebrate species. Supported by ORIP (UM1OD023222), NIDCR, and NIGMS.
Elevated Transferrin Receptor Impairs T Cell Metabolism and Function in Systemic Lupus Erythematosus
Voss et al., Science Immunol. 2023.
https://www.science.org/doi/10.1126/sciimmunol.abq0178
Systemic lupus erythematosus (SLE) is an autoimmune disease in which dysfunctional T cells exhibit abnormalities in metabolism. Investigators performed a CRISPR screen to examine mechanisms associated with the role of excess iron in dysfunctional T cells. The transferrin receptor (CD71) was identified as differentially critical for Type 1 T helper cells and inhibitory for induced regulatory T cells. Activated T cells induced CD71 and iron uptake, which was exaggerated in SLE-prone T cells. Disease severity correlated with CD71 expression in cells from male and female patients with SLE, and blocking CD71 in vitro enhanced interleukin 10 secretion. These findings suggest that T cell iron uptake via CD71 contributes to T cell dysfunction and can be targeted to limit SLE-associated pathology. Supported by ORIP (S10OD030264), NIAID, NCI, and NIDDK.
Deep Learning Is Widely Applicable to Phenotyping Embryonic Development and Disease
Naert et al., Development. 2021.
https://pubmed.ncbi.nlm.nih.gov/34739029/
Genome editing simplifies the generation of new animal models for congenital disorders. The authors illustrate how deep learning (U-Net) automates segmentation tasks in various imaging modalities. They demonstrate this approach in embryos with polycystic kidneys (pkd1 and pkd2) and craniofacial dysmorphia (six1). They provide a library of pre-trained networks and detailed instructions for applying deep learning to datasets and demonstrate the versatility, precision, and scalability of deep neural network phenotyping on embryonic disease models. Supported by ORIP (P40OD010997, R24OD030008), NICHD, NIDDK, and NIMH.
MIC-Drop: A Platform for Large-scale In Vivo CRISPR Screens
Parvez et al., Science. 2021.
https://pubmed.ncbi.nlm.nih.gov/34413171/
CRISPR screens in animals are challenging because generating, validating, and keeping track of large numbers of mutant animals is prohibitive. These authors introduce Multiplexed Intermixed CRISPR Droplets (MIC-Drop), a platform combining droplet microfluidics, single-needle en masse CRISPR ribonucleoprotein injections, and DNA barcoding to enable large-scale functional genetic screens in zebrafish. In one application, they showed that MIC-Drop could identify small-molecule targets. Furthermore, in a MIC-Drop screen of 188 poorly characterized genes, they discovered several genes important for cardiac development and function. With the potential to scale to thousands of genes, MIC-Drop enables genome-scale reverse genetic screens in model organisms. Supported by ORIP (R24OD017870), NIGMS, and NHLBI.
TGF-β1 Signaling Is Essential for Tissue Regeneration in the Xenopus Tadpole Tail
Nakamura et al., Biochemical and Biophysical Research Communications. 2021.
https://www.sciencedirect.com/science/article/pii/S0006291X21008731
Amphibians, such as Xenopus tropicalis, exhibit a remarkable capacity for tissue regeneration after traumatic injury. Nakamura et al. show that inhibition of TGF-β1 function prevents tail regeneration in Xenopus tropicalis tadpoles. CRISPR-mediated knock-out (KO) of tgfb1 retards tail regeneration; the phenotype of tgfb1 KO tadpoles can be rescued by injection of tgfb1 mRNA. Cell proliferation, critical for tissue regeneration, is downregulated in tgfb1 KO tadpoles; tgfb1 KO reduces the expression of phosphorylated Smad2/3 (pSmad2/3). These results show that TGF-β1 regulates cell proliferation through the activation of Smad2/3. They propose that TGF-β1 plays a critical role in TGF-β receptor-dependent tadpole tail regeneration in Xenopus. Supported by ORIP (P40OD010997, R24OD030008).
Nonhuman Primate Models for SARS-CoV-2 Research: Cryopreservation as a Means to Maintain Critical Models and Enhance the Genetic Diversity of Colonies
Arnegard and Hild et al., Lab Animal. 2021.
https://doi.org/10.1038/s41684-021-00792-1
This commentary, written by ORIP staff, addresses the need for improved cryopreservation methods and resources for nonhuman primate (NHP) gametes and embryos to safeguard newly developed NHP models and enhance the genetic diversity of NHP colonies without reliance on animal importations. Cryopreservation also plays critical roles in medical approaches to preserve the fertility of patients who must undergo potentially gonadotoxic treatments, as well as nascent genome editing efforts to develop new NHP models for human diseases. Given these diverse benefits to research progress, ORIP continues to fund the development of cryopreservation tools and approaches for NHPs and other animal models.
Identification of Basp1 as a Novel Angiogenesis-regulating Gene by Multi-Model System Studies
Khajavi et al., FASEB Journal. 2021.
https://pubmed.ncbi.nlm.nih.gov/33899275/
The authors previously used genetic diversity in inbred mouse strains to identify quantitative trait loci (QTLs) responsible for differences in angiogenic response. Employing a mouse genome-wide association study (GWAS) approach, the region on chromosome 15 containing Basp1 was identified as being significantly associated with angiogenesis in inbred strains. To investigate its role in vivo, they knocked out basp1 in transgenic kdrl:zsGreen zebrafish embryos using a widely adopted CRISPR-Cas9 system. They further showed that basp1 promotes angiogenesis by upregulating β-catenin gene and the Dll4/Notch1 signaling pathway. These results provide the first in vivo evidence to indicate the role of basp1 as an angiogenesis-regulating gene. Supported by ORIP (R24OD017870) and NEI.