Selected Grantee Publications
The High Affinity Dopamine D2 Receptor Agonist MCL-536: A New Tool for Studying Dopaminergic Contribution to Neurological Disorders
Subburaju et al., ACS Chemical Neuroscience. 2021.
https://pubs.acs.org/doi/full/10.1021/acschemneuro.1c00094
The dopamine D2 receptor exists in two different states, D2high and D2low; the former is the functional form of the D2 receptor and associates with intracellular G-proteins. The D2 agonist [3H]MCL-536 has high affinity for the D2 receptor (Kd 0.8 nM) and potently displaces the binding of (R-(-)-N-n-propylnorapomorphine (NPA; Ki 0.16 nM) and raclopride (Ki 0.9 nM) in competition binding assays. The authors characterized [3H]MCL-536. [3H]MCL-536 as metabolically stable. In vitro autoradiography on transaxial and coronal brain sections showed specific binding of [3H]MCL-536. [3H]MCL-536's unique properties make it a valuable tool for research on neurological disorders like Parkinson's disease or schizophrenia. Supported by ORIP (R43OD020186, R44OD024615) and NIMH.
Establishing an Immunocompromised Porcine Model of Human Cancer for Novel Therapy Development with Pancreatic Adenocarcinoma and Irreversible Electroporation
Hendricks-Wenger et al., Scientific Reports. 2021.
https://pubmed.ncbi.nlm.nih.gov/33828203/
Efficacious interventions to treat pancreatic cancer lack a preclinical model to recapitulate patients' anatomy and physiology. The authors developed RAG2/IL2RG deficient pigs using CRISPR/Cas9 with the novel application of cancer xenograft studies of human pancreatic adenocarcinoma. These pigs were successfully generated using on-demand genetic modifications in embryos. Human Panc01 cells injected into the ears of RAG2/IL2RG deficient pigs demonstrated 100% engraftment. The electrical properties and response to irreversible electroporation of the tumor tissue were found to be similar to excised human pancreatic cancer tumors. This model will be useful to bridge the gap of translating therapies from the bench to clinical application. Supported by ORIP (R21OD027062), NIBIB, and NCI.
Sensitive Tracking of Circulating Viral RNA Through All Stages of SARS-CoV-2 Infection
Huang et al., Journal of Clinical Investigation. 2021.
https://www.jci.org/articles/view/146031
Circulating SARS-CoV-2 RNA could represent a more reliable indicator of infection than nasal RNA, but quantitative reverse transcription PCR (RT-qPCR) lacks diagnostic sensitivity for blood samples. Researchers developed a CRISPR-amplified, blood-based COVID-19 (CRISPR-ABC) assay to detect SARS-CoV-2 in plasma. They evaluated the assay using samples from SARS-CoV-2-infected African green monkeys and rhesus macaques, as well as from COVID-19 patients. CRISPR-ABC consistently detected viral RNA in the plasma of the experimentally infected primates from 1 to 28 days after infection. The increases in plasma SARS-CoV-2 RNA in the monkeys preceded rectal swab viral RNA increases. In the patient cohort, the new assay demonstrated 91.2% sensitivity and 99.2% specificity versus RT-qPCR nasopharyngeal testing, and it also detected COVID-19 cases with transient or negative nasal swab RT-qPCR results. These findings suggest that detection of SARS-CoV-2 RNA in blood by CRISPR-augmented RT-PCR could improve COVID-19 diagnosis, facilitate the evaluation of SARS-CoV-2 infection clearance, and help predict the severity of infection. Supported by ORIP (P51OD011104).
Best Practices for Correctly Identifying Coronavirus by Transmission Electron Microscopy
Bullock et al., Kidney International. 2021.
https://pubmed.ncbi.nlm.nih.gov/33493525/
This paper provides strategies for identifying coronaviruses by transmission electron microscopy in ultrathin sections of tissues or tissue cultures. As illustrated by results in the literature, organ damage may be incorrectly attributed to the presence of virus, since images of coronavirus may resemble subcellular organelles. The paper also references numerous biochemical and imaging techniques to aid an investigator in avoiding pseudo positive identifications. Supported by ORIP (S10OD026776) and others.
A Pulsatile Release Platform Based on Photo-Induced Imine-Crosslinking Hydrogel Promotes Scarless Wound Healing
Zhang et al., Nature Communications. 2021.
https://pubmed.ncbi.nlm.nih.gov/33723267/
Skin wound healing is a dynamic and interactive process involving the collaborative efforts of growth factors, extracellular matrix (ECM), and different tissue and cell lineages. Although accumulating studies with a range of different model systems have increased our understanding of the cellular and molecular basis underlying skin scar formation, they have not been effectively translated to therapy. Development of effective therapeutic approaches for skin scar management is urgently needed. In this study, team of investigators devise a water-oil-water double emulsion strategy to encapsulate proteins within a photo-crosslinkable poly-lactic-co-glycolic acid (PLGA) shell, which can produce microcapsules with pulsatile drug release kinetics after administration. The results show that pulsatile release of the TGF-β inhibitor can accelerate skin wound closure while suppressing scarring in murine skin wounds and large animal preclinical models, suggesting that it could be an effective approach to achieve scarless wound healing in skin. Supported by ORIP (R01OD023700).
Autologous Transplant Therapy Alleviates Motor and Depressive Behaviors in Parkinsonian Monkeys
Tao et al., Nature Medicine. 2021.
https://www.nature.com/articles/s41591-021-01257-1
Generation of induced pluripotent stem cells (iPSCs) enables standardized of dopamine (DA) neurons for autologous transplantation therapy to improve motor functions in Parkinson disease (PD). Adult male rhesus PD monkeys receiving autologous, but not allogenic, transplantation exhibited recovery from motor and depressive signs of PD over a 2-year period without immunosuppressive therapy. Mathematical modeling showed correlations between surviving DA neurons with PET signal intensity and behavior recovery regardless of autologous or allogeneic transplant, suggesting a predictive power of PET and motor behaviors for surviving DA neuron number. The results demonstrate favorable efficacy of the autologous transplant approach to treat PD. Supported by ORIP (P51OD011106) NINDS, and NICHD.
Acoustofluidic Rotational Tweezing Enables High-Speed Contactless Morphological Phenotyping of Zebrafish Larvae
Chen et al., Nature Communications. 2021.
https://pubmed.ncbi.nlm.nih.gov/33602914/
These authors demonstrate an acoustofluidic rotational tweezing platform that enables contactless, high-speed, 3D multispectral imaging and digital reconstruction of zebrafish larvae for quantitative phenotypic analysis. The acoustic-induced polarized vortex streaming achieves contactless and rapid (~1 s/rotation) rotation of zebrafish larvae enabling multispectral imaging of the zebrafish body and internal organs. They developed a 3D reconstruction pipeline that yields accurate 3D models based on the multi-view images for quantitative evaluation. With its contactless nature and advantages in speed and automation, the acoustofluidic rotational tweezing system has the potential to be a valuable asset for developmental biology and pre-clinical drug development in pharmacology. Supported by ORIP (R43OD024963), NCI, and NIGMS.
Endogenous Zebrafish Neural Cre Drivers Generated by CRISPR/Cas9 Short Homology Directed Targeted Integration
Almeida et al., Scientific Reports. 2021.
https://pubmed.ncbi.nlm.nih.gov/33462297/
Almeida et al. previously reported precision targeted integration of reporter DNA in zebrafish using CRISPR/Cas9. Here, they isolated zebrafish Cre recombinase drivers. A 2A-Cre recombinase transgene with 48 bp homology arms was targeted into proneural genes ascl1b, olig2 and neurod1. They observed high rates of germline transmission from 10 to 100% (10% olig2; 20% neurod1; 100% ascl1b). The lines Tg(ascl1b-2A-Cre)is75, Tg(olig2-2A-Cre)is76, and Tg(neurod1-2A-Cre)is77 expressed functional Cre recombinase in the cell populations. Results demonstrate Cre recombinase expression is driven by the native promoter and regulatory elements of targeted genes. This approach is a cost-effective method to generate cell type specific zebrafish Cre and CreERT2 drivers. Supported by ORIP (R24OD020166).
Thresholds for Post-Rebound SHIV Control after CCR5 Gene-Edited Autologous Hematopoietic Cell Transplantation
Cardozo-Ojeda et al., eLife. 2021.
https://elifesciences.org/articles/57646
Investigators developed a mathematical model to project the minimum threshold of C-C chemokine receptor type 5 (CCR5) gene-edited cells necessary for a functional cure from HIV. This was based on blood T cell reconstitution and plasma simian-HIV (SHIV) dynamics from SHIV-1157ipd3N4-infected juvenile pig-tailed macaques that underwent autologous transplantation with CCR5 gene editing. The model predicts that viral control can be obtained following analytical treatment interruption (ATI) when: (1) transplanted hematopoietic stem and progenitor cells (HSPCs) are at least fivefold higher than residual endogenous HSPCs after total body irradiation and (2) the fraction of protected HSPCs in the transplant achieves a threshold (76–94%) sufficient to overcome transplantation-dependent loss of SHIV immunity. Under these conditions, if ATI is withheld until transplanted gene-modified cells engraft and reconstitute to a steady state, spontaneous viral control is projected to occur. Supported by ORIP (P51OD010425), NCATS and NIAID.
Deploying MMEJ using MENdel in Precision Gene Editing Applications for Gene Therapy and Functional Genomics
Martínez-Gálvez et al., Nucleic Acids Research. 2021.
https://academic.oup.com/nar/article/49/1/67/6030233
Gene-editing experiments commonly elicit the error-prone non-homologous end joining for DNA double-strand break (DSB) repair. Martinez-Galvez et al. compared three DSB repair prediction algorithms - MENTHU, inDelphi, and Lindel. MENTHU correctly identified 46% of all PreMAs available, a ∼2- and ∼60-fold sensitivity increase compared to inDelphi and Lindel, respectively. The investigators report the new algorithm MENdel, a combination of MENTHU and Lindel, that achieves the most predictive coverage of homogeneous out-of-frame mutations. They suggest that the use of MENdel helps researchers use MMEJ at scale for reverse genetics screenings to be viable for nearly all loss-of-function based gene editing therapeutic applications. Supported by ORIP (R24OD020166) and NIGMS.