Selected Grantee Publications
Establishing the Hybrid Rat Diversity Program: A Resource for Dissecting Complex Traits
Dwinell et al., Mammalian Genome. 2025.
https://pubmed.ncbi.nlm.nih.gov/39907792
Rat models have been extensively used for studying human complex disease mechanisms, behavioral phenotypes, and environmental factors and for discovering and developing drugs. Systems genetics approaches have been used to study the effects of both genetic variation and environmental factors. This approach recognizes the complexity of common disorders and uses intermediate phenotypes to find relationships between genetic variation and clinical traits. This article describes the Hybrid Rat Diversity Program (HDRP) at the Medical College of Wisconsin, which involves 96 inbred rat strains and aims to provide a renewable and reusable resource in terms of the HRDP panel of inbred rat strains, the genomic data derived from the HRDP strains, and banked resources available for additional studies. Supported by ORIP (R24OD024617) and NHLBI.
Functional Differences Between Rodent and Human PD-1 Linked to Evolutionary Divergence
Masubuchi et al., Science Immunology. 2025.
https://pubmed.ncbi.nlm.nih.gov/39752535/
Programmed cell death protein 1 (PD-1), an immune checkpoint receptor, regulates immunity against cancer. Rodent models (e.g., mice) do not exhibit the same response rates and immune-related adverse effects to PD-1 blocking drugs as patients with cancer. Only 59.6% amino acid sequence identity is conserved in human PD-1 (hu PD-1) and mouse PD-1 (mo PD-1). Researchers used mouse tumor models, coculture assays, and biophysical assays to determine key functional and biochemical differences between hu PD-1 and mo PD-1. HuPD-1 demonstrates stronger suppressive activity of interleukin-2 secretion and CD69 expression than mo PD-1 because of the ectodomain and intracellular domain, but not the transmembrane domain. Analysis of rodent evolution demonstrated that other inhibitory immunoreceptors were positively selected or had selection intensification over PD-1. Understanding the conservation and divergence of PD-1 signaling at the molecular level in humans compared with mice is needed to properly translate preclinical data to clinical therapeutics. Supported by ORIP (S10OD026929), NCI, and NIA.
Targeting Pancreatic Cancer Cell Stemness by Blocking Fibronectin-Binding Integrins on Cancer-Associated Fibroblasts
Wu et al., Cancer Research Communications. 2025.
https://pubmed.ncbi.nlm.nih.gov/39785683
Cancer-associated fibroblasts (CAFs) stimulate the formation and progression of pancreatic adenocarcinoma (PDAC) through the generation of extracellular matrix (ECM). Researchers developed a bispecific antibody (bsAb) that targets α5β1 and αvβ3 integrins expressed on CAFs. Blockade using the bsAb resulted in reduced assembly of fibronectin and collagen fibers in vitro. An antifibrotic effect was observed when CAFs were plated for 72 hours prior to bsAb treatment; pre-deposited ECM was disrupted. Six- to 8-week-old female nu/nu mice treated with bsAb demonstrated fewer tumors and reduced tumor stiffness compared with those exposed to only CAFs co-injected with PDAC cells. These results support a potential novel PDAC therapeutic that targets CAF-mediated fibronectin assembly and ECM production. Supported by ORIP (K01OD030513) and NCI.
An NR2F1-Specific Agonist Suppresses Metastasis by Inducing Cancer Cell Dormancy
Khalil et al., The Journal of Experimental Medicine. 2021.
Researchers described the discovery of a nuclear receptor NR2F1 antagonist that specifically activates dormancy programs in malignant cells. Agonist treatment resulted in a self-regulated increase in NR2F1 mRNA and protein and downstream transcription of a novel dormancy program. This program led to growth arrest in multiple human cell lines, as well as patient-derived organoids. This effect was lost when NR2F1 was knocked out. In mice, agonist treatment resulted in inhibition of lung metastasis of head and neck squamous cell carcinomas, even after cessation of the treatment. This work provides proof of principle supporting the use of NR2F1 agonists to induce dormancy as a therapeutic strategy to prevent metastasis. Supported by ORIP (S10OD018522 and S10OD026880) and others.
Sexual Dimorphic Impact of Adult-Onset Somatopause on Life Span and Age-Induced Osteoarthritis
Poudel et al., Aging Cell. 2021.
https://pubmed.ncbi.nlm.nih.gov/?term=Poudel%20SB&cauthor_id=34240807
Osteoarthritis (OA) is a major cause of disability worldwide. In humans, the age-associated decline in growth hormone (GH) levels was hypothesized to play a role in the etiology of OA. Investigators studied the impact of adult-onset isolated GH deficiency (AOiGHD) on the life span and skeletal integrity in aged mice. Reductions in GH during adulthood were associated with extended life span and reductions in body temperature in female mice only. However, end-of-life pathology revealed high levels of lymphomas in both sexes, independent of GH status. Skeletal characterization revealed increases in OA severity in AOiGHD mice. In conclusion, while their life span increased, AOiGHD female mice’s health span was compromised by high-grade lymphomas and the development of severe OA. In contrast, AOiGHD males, which did not show extended life span, showed an overall low grade of lymphomas but exhibited significantly decreased health span, evidenced by increased OA severity. Supported by ORIP (S10OD010751) and others.
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.
Phase Separation Drives Aberrant Chromatin Looping and Cancer Development
Ahn et al., Nature. 2021.
https://doi.org/10.1038/s41586-021-03662-5
How unstructured intrinsically disordered regions (IDRs) contribute to oncogenesis is elusive. Using an Orbitrap fusion tribrid mass spectrometer, investigators show that IDRs contained within NUP98–HOXA9, a homeodomain-containing transcription factor chimera recurrently detected in leukaemias, are essential for establishing liquid–liquid phase separation (LLPS) puncta of chimera and for inducing leukaemic transformation. LLPS of NUP98–HOXA9 not only promotes chromatin occupancy of chimera transcription factors, but also is required for the formation of a broad “super-enhancer”-like binding pattern typically seen at leukaemogenic genes, which potentiates transcriptional activation. An artificial HOX chimera, created by replacing the phenylalanine and glycine repeats of NUP98 with an unrelated LLPS-forming IDR of the FUS protein, had similar enhancing effects on the genome-wide binding and target gene activation of the chimera. This report describes a proof-of-principle example in which cancer acquires mutation to establish oncogenic transcription factor condensates via phase separation, which simultaneously enhances their genomic targeting and induces organization of aberrant three-dimensional chromatin structure during tumor transformation. Supported by ORIP (S10OD018445).
Single-Cell Protein Activity Analysis Identifies Recurrence-Associated Renal Tumor Macrophages
Obradovic et al., Cell. 2021.
https://doi.org/10.1016/j.cell.2021.04.038
Post-surgery course of clear cell renal carcinoma (ccRCC) is mixed because of the heterogeneity of the disease. Using high-performance computing cluster and storage systems, investigators established an inclusive ccRCC tumor microenvironment (TME) map by using single-cell RNA sequencing data of subpopulations of tumor and tumor-adjacent tissues. Analysis of the data identified key TME subpopulations as well as their master regulators and candidate cell-cell interactions, revealing clinically relevant cell populations. Specifically, the study uncovered a tumor-specific macrophage subpopulation, validated by spatially resolved, quantitative multispectral immunofluorescence. In a large clinical validation cohort, markers of this subpopulation were significantly enriched in tumors from patients who recurred following surgery. Supported by ORIP (S10OD012351, S10OD021764) and others.
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.
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.