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.
A Participant-Derived Xenograft Model of HIV Enables Long-Term Evaluation of Autologous Immunotherapies
McCann et al., Journal of Experimental Medicine. 2021.
https://doi.org/10.1084/jem.20201908
HIV-specific CD8+ T cells partially control viral replication but rarely provide lasting protection due to immune escape. Investigators showed that engrafting NSG mice with memory CD4+ T cells from HIV+ donors enables evaluation of autologous T cell responses while avoiding graft-versus-host disease. Treating HIV-infected mice with clinically relevant T cell products reduced viremia. In vivo activity was significantly enhanced when T cells were engineered with surface-conjugated nanogels carrying an Interleukin-15 superagonist but was ultimately limited by the pervasive selection of escape mutations, recapitulating human patterns. This “participant-derived xenograft” model provides a powerful tool for developing T cell-based therapies for HIV. Supported by ORIP (R01OD011095), NIAID, NIDA, NIMH, NINDS, and NCATS.
Postpubertal Spermatogonial Stem Cell Transplantation Restores Functional Sperm Production in Rhesus Monkeys Irradiated Before and After Puberty
Shetty et al., Andrology. 2021.
https://onlinelibrary.wiley.com/doi/10.1111/andr.13033
Cancer treatment of prepubertal patients impacts future fertility due to the abolition of spermatogonial stem cells (SSCs). Prepubertal rhesus monkeys (n=6) were unilaterally castrated, and the remaining testes irradiated twice to insure loss of SSCs; the animals were treated with a vehicle or GnRH antagonist for 8 weeks (n=3/treatment). The cryopreserved prepubertal testicular tissue was allergenically transplanted into the intact testes of the monkeys after puberty. Recovery of viable donor epididymal sperm was observed in half the monkeys. These results illustrate that sperm production can be restored in primates by transplantation of testicular cells from cryopreserved untreated prepubertal testes into seminiferous tubules of the remaining testes. Supported by ORIP (P51OD011092), NICHD, and NCI.
Evidence in Primates Supporting the Use of Chemogenetics for the Treatment of Human Refractory Neuropsychiatric Disorders
Roseboom et al., Molecular Therapy. 2021.
https://doi.org/10.1016/j.ymthe.2021.04.021
A rhesus macaque model for pathological anxiety was used to investigate the feasibility of decreasing anxiety using chemogenetics, known as DREADDs (designer receptors exclusively activated by designer drugs), to reduce amygdala neuronal activity. A low-dose clozapine administration strategy was developed to induce DREADD-mediated amygdala inhibition. Compared to controls, clozapine selectively decreased anxiety-related freezing behavior in the human intruder paradigm in the chemogentic monkeys, while coo vocalizations and locomotion were unaffected. These results are an important step in establishing chemogenetic strategies for patients with refractory neuropsychiatric disorders in which amygdala alterations are central to disease pathophysiology. Supported by ORIP (P51OD011106), NIMH, and NICHD.
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.
Metabolomics Analysis of Follicular Fluid Coupled With Oocyte Aspiration Reveals Importance of Glucocorticoids in Primate Periovulatory Follicle Competency
Ravisankar et al., Scientific Reports. 2021.
https://www.nature.com/articles/s41598-021-85704-6
Assisted reproductive therapy in primates requires ovarian stimulation protocols, which result in multiple heterogeneous oocytes with variable capacity for fertilization, cleavage, and blastocyst formation. Recovered oocytes from rhesus macaque follicles (n=74 follicles) were fertilized in vitro and classified as failed to cleave, cleaved but arrested, or able to form blastocysts. Metabolomics analysis of the follicular fluid identified 60 metabolites that were different among embryo classifications; key was an increase in the intrafollicular ratio of cortisol to cortisone in the blastocyst group, which was associated with translocation of the glucocorticoid receptor, NR3C1. The data suggest a role for NR3C1 in the regulation of follicular processes, such as expansion of cumulus granulosa cells, via paracrine signaling. Supported by ORIP (P51OD011092) and NICHD.
A Chromosome-Level Genome of Astyanax mexicanus Surface Fish for Comparing Population-Specific Genetic Differences Contributing to Trait Evolution
Warren et al., Nature Communications. 2021.
https://pubmed.ncbi.nlm.nih.gov/33664263/
Identifying the genetic factors that underlie complex traits is central to understanding the mechanistic underpinnings of evolution. Cave-dwelling Astyanax mexicanus populations are well adapted to subterranean life and many populations appear to have evolved troglomorphic (morphological adaptation of an animal to living in the constant darkness of caves) traits independently, while the surface-dwelling populations can be used as a proxy for the ancestral form. Warren et al. present a high-resolution, chromosome-level surface fish genome, enabling the first genome-wide comparison between surface fish and cavefish populations. Using this resource, they performed quantitative trait locus (QTL) mapping analyses and found new candidate genes for eye loss (dusp26). They also generated the first genome-wide evaluation of deletion variability across cavefish populations to gain insight into this potential source of cave adaptation. The surface fish genome reference now provides a more complete resource for comparative, functional and genetic studies of drastic trait differences within a species. Supported by ORIP (R24OD011198), NIA, NICHD, NIGMS, amd NIDCR.
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.
Increased Proviral DNA in Circulating Cells Correlates With Plasma Viral Rebound in SIV-Infected Rhesus Macaques after Antiretroviral Therapy Interruption
Ziani et al., Journal of Virology. 2021.
https://jvi.asm.org/content/early/2021/01/05/JVI.02064-20
Investigators longitudinally tracked dynamic decay of cell-associated viral RNA/DNA in systemic and lymphoid tissues in SIV-infected rhesus macaques on prolonged combined antiretroviral therapy (cART) to evaluate predictors of viral rebound after treatment cessation. Suppressive cART substantially reduced plasma SIV RNA, cell-associated unspliced, and multiply spliced SIV RNA to undetectable levels, yet viral DNA remained detectable in systemic tissues and lymphoid compartments throughout cART. A rapid increase of integrated proviral DNA in peripheral mononuclear cells was detected once cART was withdrawn, accompanied by the emergence of detectable plasma viral load. The increase of peripheral proviral DNA post cART interruption correlated with the emergence and degree of viral rebound. These results suggest that measuring total viral DNA in SIV infection may be a relatively simple surrogate marker of reservoir size, and may predict viral rebound after treatment interruption, and inform treatment strategies. Supported by ORIP (P51OD011104), NIAID and NICHD.
A Frog with Three Sex Chromosomes that Co-Mingle Together in Nature: Xenopus tropicalis Has a Degenerate W and a Y that Evolved from a Z Chromosome
Furman et al., PLOS Genetics. 2020.
https://pubmed.ncbi.nlm.nih.gov/33166278/
Genetic systems governing sexual differentiation vary among species. Furman et al. investigated a frog with three sex chromosomes, the Western clawed frog, Xenopus tropicalis. They demonstrate that natural populations from the western and eastern edges of Ghana have a young Y chromosome, and that a male-determining factor on this Y chromosome is in a similar genomic location as a previously known female-determining factor on the W chromosome. Their findings are consistent with theoretical expectations associated with recombination suppression on sex chromosomes and demonstrate that several characteristics of old and established sex chromosomes can arise well before they become cytogenetically distinguished. Supported by ORIP (P40OD010997) and NICHD.