Selected Grantee Publications
Advancing Human Disease Research with Fish Evolutionary Mutant Models
Beck et al., Trends in Genetics. 2021.
https://pubmed.ncbi.nlm.nih.gov/34334238/
Model organism research is essential to understand disease mechanisms. However, laboratory-induced genetic models can lack genetic variation and often fail to mimic disease severity. Evolutionary mutant models (EMMs) are species with evolved phenotypes that mimic human disease. They have improved our understanding of cancer, diabetes, and aging. Fish are the most diverse group of vertebrates, exhibiting a kaleidoscope of specialized phenotypes, many that would be pathogenic in humans but are adaptive in the species' specialized habitat. Evolved compensations can suggest avenues for novel disease therapies. This review summarizes current research using fish EMMs to advance our understanding of human disease. Supported by ORIP (R01OD011116), NIA, NIDA, and NIGMS.
Factor XII Plays a Pathogenic Role in Organ Failure and Death in Baboons Challenged with Staphylococcus aureus
Silasi et al., Blood. 2021.
https://pubmed.ncbi.nlm.nih.gov/33598692/
Activation of coagulation factor (F) XI promotes multiorgan failure in rodent models of sepsis and in a baboon model for lethal systemic inflammation induced by infusion of heat-inactivated Staphylococcus aureus. The authors used the anticoagulant FXII-neutralizing antibody 5C12 to verify the mechanistic role of FXII. Inhibition of FXII prevented fever, terminal hypotension, respiratory distress, and multiorgan failure. All animals receiving 5C12 had milder and transient clinical symptoms; untreated control animals suffered irreversible multiorgan failure. This study confirms their previous finding that at least two enzymes of FXIa and FXIIa play critical roles in the development of an acute and terminal inflammatory response. Supported by ORIP (P40OD024628), NIAID, NHLBI, and NIGMS.
In Vitro and In Vivo Functions of SARS-CoV-2 Infection-Enhancing and Neutralizing Antibodies
Li et al., Cell. 2021.
https://doi.org/10.1016/j.cell.2021.06.021
Antibody-dependent enhancement of infection is a concern for clinical use of antibodies. Researchers isolated neutralizing antibodies against the receptor-binding domain (RBD) or N-terminal domain (NTD) of SARS-CoV-2 spike from COVID-19 patients. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific binding modes. RBD and NTD antibodies mediated both neutralization and infection enhancement in vitro. However, infusion of these antibodies into mice or macaques resulted in suppression of virus replication, demonstrating that antibody-enhanced infection in vitro does not necessarily predict enhanced infection in vivo. RBD-neutralizing antibodies having cross-reactivity against coronaviruses were protective against SARS-CoV-2, the most potent of which was DH1047. Supported by ORIP (P40OD012217, U42OD021458, S10OD018164), NIAID, NCI, NIGMS, and NIH Common Fund.
Loss of Gap Junction Delta-2 (GJD2) Gene Orthologs Leads to Refractive Error in Zebrafish
Quint et al., Communications Biology. 2021.
https://pubmed.ncbi.nlm.nih.gov/34083742/
Myopia is the most common developmental disorder of juvenile eyes. Although little is known about the functional role of GJD2 in refractive error development, the authors find that depletion of gjd2a (Cx35.5) or gjd2b (Cx35.1) orthologs in zebrafish cause changes in eye biometry and refractive status. Their immunohistological and scRNA sequencing studies show that Cx35.5 (gjd2a) is a retinal connexin; its depletion leads to hyperopia and electrophysiological retina changes. They found a lenticular role; lack of Cx35.1 (gjd2b) led to a nuclear cataract that triggered axial elongation. The results provide functional evidence of a link between gjd2 and refractive error. Supported by ORIP (R24OD026591), NIGMS, and NINDS.
Cell-Specific Transcriptional Control of Mitochondrial Metabolism by TIF1γ Drives Erythropoiesis
Rossmann et al., Science. 2021.
https://pubmed.ncbi.nlm.nih.gov/33986176/
Transcription and metabolism both influence cell function but dedicated transcriptional control of metabolic pathways that regulate cell fate has rarely been defined. The authors discovered that inhibition of the pyrimidine biosynthesis enzyme dihydroorotate dehydrogenase (DHODH) rescues erythroid differentiation in bloodless zebrafish moonshine (mon) mutant embryos defective for transcriptional intermediary factor 1 gamma (tif1γ). Upon tif1γ loss, CoQ levels are reduced, and a high succinate/α-ketoglutarate ratio leads to increased histone methylation. A CoQ analog rescues mon's bloodless phenotype. These results demonstrate that mitochondrial metabolism is a key output of a lineage transcription factor that drives cell fate decisions in the early blood lineage. Supported by ORIP (R24OD017870), NIGMS, NHLBI, and NCI.
Cryopreservation Method for Drosophila melanogaster Embryos
Zhan et al., Nature Communications. 2021.
https://www.nature.com/articles/s41467-021-22694-z
Drosophila melanogaster is a premier model for biomedical research. However, preservation of Drosophila stocks is labor intensive and costly. Researchers at University of Minnesota reported an efficient method for cryopreservation by optimizing key steps including embryo permeabilization and cryoprotectant agent loading. This method resulted in more than 10% of embryos developing into fertile adults after cryopreservation for 25 distinct strains from different sources. The further optimization and wide adoption of this protocol will solve the long-standing issue in reliably preserving Drosophila stocks and will significantly impact Drosophila as a model organism for biomedical research. Supported by ORIP (R21OD028758) and NIGMS.
Characterization of Axolotl Lampbrush Chromosomes by Fluorescence In Situ Hybridization and Immunostaining
Keinath et al., Experimental Cell Research. 2021.
https://pubmed.ncbi.nlm.nih.gov/33675804/
The lampbrush chromosomes (LBCs) in oocytes of the Mexican axolotl (Ambystoma mexicanum) were identified by their relative lengths and predicted centromeres; they have never been associated completely with the mitotic karyotype, linkage maps, or genome assembly. The authors identified 9 of the axolotl LBCs using RNA sequencing to identify actively transcribed genes and 13 bacterial artificial clone probes containing pieces of active genes. This study presents a simple and reliable way to identify each axolotl LBC cytologically and to anchor chromosome-length sequences to the LBCs by immunostaining and fluorescence in situ hybridization. This data will facilitate a more detailed analysis of LBC loops. Supported by ORIP (P40OD019794, R24OD010435) and NIGMS.
Functional Convergence of a Germline-Encoded Neutralizing Antibody Response in Rhesus Macaques Immunized with HCV Envelope Glycoproteins
Chen et al., Immunity. 2021.
https://doi.org/10.1016/j.immuni.2021.02.013
Immunoglobulin heavy chain variable gene IGHV1-69-encoded broadly neutralizing antibodies (bnAbs) targeting the hepatitis C virus (HCV) envelope glycoprotein (Env) E2 are important for protection against HCV infection in humans. An IGHV1-69 ortholog, VH1.36, is preferentially used for bnAbs isolated from rhesus macaques immunized against HCV Env. Researchers investigated the genetic, structural, and functional properties of VH1.36-encoded bnAbs generated by HCV Env vaccination of macaques and compared their findings to IGHV1-69-encoded bnAbs from HCV patients. The investigators found that macaque VH1.36- and human IGHV1-69-encoded bnAbs share many common features, which provides an excellent framework for rational HCV vaccine design and testing. Supported by ORIP (P51OD011133, U42OD010442), NIAID, NCI, and NIGMS.
The SARS-CoV-2 Receptor and Other Key Components of the Renin-Angiotensin-Aldosterone System Related to COVID-19 are Expressed in Enterocytes in Larval Zebrafish
Postlethwait et al., Biology Open. 2021.
https://bio.biologists.org/content/10/3/bio058172.article-info
Hypertension and respiratory inflammation are exacerbated by the Renin-Angiotensin-Aldosterone System (RAAS), which normally protects from dropping blood pressure via Angiotensin II (Ang II) produced by the enzyme Ace. The Ace paralog Ace2 degrades Ang II and serves as the SARS-CoV-2 receptor. To exploit zebrafish to understand the relationship of RAAS to COVID-19, the group conducted genomic and phylogenetic analyses. Results identified a type of enterocyte as the expression site of zebrafish orthologs of key RAAS components, including the SARS-CoV-2 co-receptor. Results identified vascular cell subtypes expressing Ang II receptors and identified cell types to exploit zebrafish as a model for understanding COVID-19 mechanisms. Supported by ORIP (R24OD026591, R01OD011116), NIGMS, NICHD.
Creb5 Establishes the Competence for Prg4 Expression in Articular Cartilage
Zhang et al., Communications Biology. 2021.
https://doi.org/10.1038/s42003-021-01857-0
Cells comprising the superficial zone of articular cartilage express lubricin, encoded by the Prg4 gene, that lubricates joints. Researchers identified Creb5 as a transcription factor that is required for TGF-β and EGFR signaling to induce Prg4 expression. Forced expression of Creb5 in deep-zone chondrocytes of articular cartilage confers competence for TGF-β and EGFR signals to induce Prg4 expression. The researchers showed that Creb5 directly binds to two Prg4 promoter-proximal regulatory elements, which work together with a more distal regulatory element to drive induction of Prg4 by TGF-β. Thus, Creb5 is a critical regulator of Prg4/lubricin expression in the articular cartilage. Supported by ORIP (U42OD11158), NIAMS, and NIDDK.