Selected Grantee Publications
Multimodal Analysis of Dysregulated Heme Metabolism, Hypoxic Signaling, and Stress Erythropoiesis in Down Syndrome
Donovan et al., Cell Reports. 2024.
https://pubmed.ncbi.nlm.nih.gov/39120971
Down syndrome (DS), a genetic condition caused by the presence of an extra copy of chromosome 21, is characterized by intellectual and developmental disability. Infants with DS often suffer from low oxygen saturation, and DS is associated with obstructive sleep apnea. Investigators assessed the role that hypoxia plays in driving health conditions that are comorbid with DS. A multiomic analysis showed that people with DS exhibit elevated heme metabolism and activated stress erythropoiesis, which are indicators of chronic hypoxia; these results were recapitulated in a mouse model for DS. This study identified hypoxia as a possible mechanism underlying several conditions that co-occur with DS, including congenital heart defects, seizure disorders, autoimmune disorders, several leukemias, and Alzheimer's disease. Supported by ORIP (R24OD035579), NCATS, NCI, and NIAID.
Epigenetic MLH1 Silencing Concurs With Mismatch Repair Deficiency in Sporadic, Naturally Occurring Colorectal Cancer in Rhesus Macaques
Deycmar et al., Journal of Translational Medicine. 2024.
https://pubmed.ncbi.nlm.nih.gov/38504345
Rhesus macaques serve as a useful model for colorectal cancer (CRC) in humans, but more data are needed to understand the molecular pathogenesis of these cancers. Using male and female rhesus macaques, researchers investigated mismatch repair status, microsatellite instability, genetic mutations, transcriptional differences, and epigenetic alterations associated with CRC. Their data indicate that epigenetic silencing suppresses MLH1 transcription, induces the loss of MLH1 protein, abrogates mismatch repair, and drives genomic instability in naturally occurring CRC in rhesus macaques. This work provides a uniquely informative model for human CRC. Supported by ORIP (P51OD011092, R24OD010947, R24OD021324, P40OD012217, U42OD010426, T35OD010946, T32OD010957), NCATS, and NCI.
CDK4/6 Inhibition Sensitizes Intracranial Tumors to PD-1 Blockade in Preclinical Models of Brain Metastasis
Nayyer et al., Clinical Cancer Research. 2024.
Brain metastases are associated with high morbidity and are often resistant to immune checkpoint inhibitors. In this study, investigators evaluated the efficacy of combining CDKi (abemaciclib) and anti–PD-1 therapy (“combination therapy”) in mouse models for brain metastases, elucidated how combination therapy remodeled the tumor–immune microenvironment (TIME) and T-cell receptor (TCR) repertoires, and investigated the effects of CDKi on T-cell development and maintenance in NOD-scid Il2rgnull (NSG) mice engrafted with human immune systems (“humanized mice”). Results offer a strong rationale for the clinical evaluation of combination CDKi and PD-1 blockade in patients with brain metastases. Supported by ORIP (R24OD026440), NCI, and NIAID.
Early Detection of Pseudocapillaria tomentosa by qPCR in Four Lines of Zebrafish, Danio rerio (Hamilton 1882)
Schuster et al., Journal of Fish Diseases. 2023.
https://onlinelibrary.wiley.com/doi/10.1111/jfd.13773
The intestinal nematode Pseudocapillaria tomentosa in zebrafish (Danio rerio) causes profound intestinal lesions, emaciation, and death and is a promoter of a common intestinal cancer in zebrafish. This nematode has been detected in an estimated 15% of zebrafish laboratories. Adult worms are readily detected about 3 weeks after exposure by either histology or wet mount preparations of the intestine, and larval worms are inconsistently observed in fish before this time. A quantitative PCR (qPCR) test was recently developed to detect the worm in fish and water, and here the authors determined that the test on zebrafish intestines was effective for earlier detection. Supported by ORIP (R24OD010998, P40OD011021).
Rbbp4 Loss Disrupts Neural Progenitor Cell Cycle Regulation Independent of Rb and Leads to Tp53 Acetylation and Apoptosis
Schultz-Rogers et al., Developmental Dynamics. 2022.
https://www.doi.org/10.1002/dvdy.467
Retinoblastoma binding protein 4 (Rbbp4) is a component of transcription regulatory complexes that control cell cycle gene expression by cooperating with the Rb tumor suppressor to block cell cycle entry. The authors used genetic analysis to examine the interactions of Rbbp4, Rb, and Tp53 in zebrafish neural progenitor cell cycle regulation and survival. Rbbp4 is upregulated across the spectrum of human embryonal and glial brain cancers, and it is essential for zebrafish neurogenesis. Rbbp4 loss leads to apoptosis and γ-H2AX in the developing brain that is suppressed by tp53 knockdown or maternal zygotic deletion. Mutant retinal neural precursors accumulate in M phase and fail to initiate G0 gene expression. Rbbp4; Rb1 double mutants show an additive effect on the number of M phase cells. The study demonstrates that Rbbp4 is necessary for neural progenitor cell cycle progression and initiation of G0, independent of Rb, and suggests that Rbbp4 is required for cell cycle exit and contributes to neural progenitor survival. Supported by ORIP (R24OD020166) and NIGMS.
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.
Intra-Strain Genetic Variation of Platyfish (Xiphophorus maculatus) Strains Determines Tumorigenic Trajectory
Lu et al., Frontiers in Genetics . 2020.
https://www.frontiersin.org/articles/10.3389/fgene.2020.562594/full
Xiphophorus interspecies hybrids represent a valuable model system to study heritable tumorigenesis. Although the ancestors of the two X. maculatus parental lines, Jp163 A and Jp163 B, were siblings produced by the same mother, backcross interspecies hybrid progeny between X. hellerii and X. maculatus Jp163 A develop spontaneous melanoma initiating at the dorsal fin due to a regulator encoded by the X. maculatus genome; the backcross hybrid progeny with X. hellerii or X. couchianus and Jp163 B exhibit melanoma on their flanks. Comparative genomic analyses revealed genetic differences are associated with pathways highlighting fundamental cellular functions. Disruption of these baselines may give rise to spontaneous or inducible tumorigenesis. Supported by ORIP (R24OD011120), NCI, and NIGMS.