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.
Impaired Axon Initial Segment Structure and Function in a Model of ARHGEF9 Developmental and Epileptic Encephalopathy
Wang et al., PNAS. 2024.
https://www.pnas.org/doi/10.1073/pnas.2400709121
Researchers developed a mouse model carrying the G55A missense variant identified in ARHGEF9 patients with severe epilepsy and neurodevelopmental phenotypes. Using male Arhgef9G55A mice, this study examined behavioral, molecular, and electrophysiological phenotypes in the Arhgef9G55A model of developmental and epileptic encephalopathies (DEE). Researchers found that the G55A variant causes disruption of inhibitory postsynaptic organization and axon initial segment (AIS) architecture, leading to impairment of both synaptic transmission and action potential generation. The effects of Arhgef9G55A on neuronal function affect both intrinsic and synaptic excitability and preferentially impair AIS. These findings indicate a novel pathological mechanism of DEE and represent a unique example of a neuropathological condition converging from AIS dysfunctions. Supported by ORIP (U54OD020351, U54OD030187, U54OD020351, S10OD026974) and NINDS.
Engineered Deletions of HIV Replicate Conditionally to Reduce Disease in Nonhuman Primates
Pitchai et al., Science. 2024.
https://pubmed.ncbi.nlm.nih.gov/39116226/
Current antiretroviral therapy (ART) for HIV is limited by the necessity for continuous administration. Discontinuation of ART leads to viral rebound. A therapeutic interfering particle (TIP) was developed as a novel single-administration HIV therapy using defective interfering particles. TIP treatment in two humanized mouse models demonstrated a significant reduction in HIV viral load. TIP intervention was completed 24 hours prior to a highly pathogenic simian immunodeficiency virus (SIV) challenge in a nonhuman primate (NHP) rhesus macaque infant model. Compared to untreated SIV infection, NHPs that received TIP treatment displayed no visible signs of SIV-induced AIDS and exhibited improved seroconversion and a significant survival advantage to the 30-week clinical endpoint. Peripheral blood mononuclear cells isolated from HIV-infected patients showed that TIP treatment reduced HIV outgrowth. This study demonstrates the potential use of a single-administration TIP for HIV treatment. Supported by ORIP (P51OD011092, U42OD010426), NCI, NIAID, and NIDA.
Impaired Skeletal Development by Disruption of Presenilin-1 in Pigs and Generation of Novel Pig Models for Alzheimer's Disease
Uh et al., Journal of Alzheimer's Disease. 2024.
https://pubmed.ncbi.nlm.nih.gov/39177593/
This study explored the effects of presenilin 1 (PSEN1) disruption on vertebral malformations in male and female PSEN1 mutant pigs. Researchers observed significant skeletal impairments and early deaths in pigs with a PSEN1 null mutation, mirroring phenotypes seen in mouse models of Alzheimer’s disease (AD). This porcine model provides valuable insights into pathological hallmarks of PSEN1 mutations in AD, offering a robust platform of therapeutic exploration. The findings establish pigs as an essential translational model for AD, enabling advanced studies on pathophysiology and treatment development for human skeletal and neurological conditions. Supported by ORIP (U42OD011140), NHLBI, NIA, NIAID.
Gene Editing of Pigs to Control Influenza A Virus Infections
Kwon et al., Emerging Microbes & Infections. 2024.
https://pubmed.ncbi.nlm.nih.gov/39083026/
A reduction in the efficacy of vaccines and antiviral drugs for combating infectious diseases in agricultural animals has been observed. Generating genetically modified livestock species to minimize susceptibility to infectious diseases is of interest as an alternative approach. The researchers developed a homozygous transmembrane serine protease 2 (TMPRSS2) knockout (KO) porcine model to investigate resistance to two influenza A virus (IAV) subtypes, H1N1 and H3N2. TMPRSS2 KO pigs demonstrated diminished nasal cavity viral shedding, lower viral burden, and reduced microscopic lung pathology compared with wild-type (WT) pigs. In vitro culturing of primary bronchial epithelial cells (PBECs) demonstrated delayed viral replication in TMPRSS2 KO pigs compared with WT pigs. This study demonstrates the potential use of genetically modified pigs to mitigate IAV infections in pigs and limit transmission to humans. Supported by ORIP (U42OD011140), NHLBI, NIAID, and NIGMS.
The Role of ATP Citrate Lyase in Myelin Formation and Maintenance
Schneider et al., Glia. 2024.
https://pubmed.ncbi.nlm.nih.gov/39318247/
Myelin formation by Schwann cells is critical for peripheral nervous system development and long-term neuronal function. The study examined how acetyl coenzyme A (acetyl-CoA), essential for lipid synthesis in myelin, is derived, with a focus on mitochondrial ATP citrate lysate (ACLY). By using both sexes in a Schwann cell–specific ACLY knockout mouse model, the authors reported that ACLY plays a role in acetyl-CoA supply for myelin maintenance but not myelin formation. ACLY is necessary for sustaining myelin gene expression and preventing nerve injury pathways. This work highlights a unique dependency on mitochondrial acetyl-CoA for Schwann cell integrity, providing insights into lipid metabolism in neuronal repair. Supported by ORIP (T35OD011078), NICHD, and NINDS.
The Splicing Factor hnRNPL Demonstrates Conserved Myocardial Regulation Across Species and Is Altered in Heart Failure
Draper et al., FEBS Letters. 2024.
https://pubmed.ncbi.nlm.nih.gov/39300280/
The 5-year mortality rate of heart failure (HF) is approximately 50%. Gene splicing, induced by splice factors, is a post-transcriptional modification of mRNA that may regulate pathological remodeling in HF. Researchers investigated the role of the splice factor heterogenous nuclear ribonucleoprotein-L (hnRNPL) in cardiomyopathy. hnRNPL protein expression is significantly increased in a male C57BL/6 transaortic constriction–induced HF mouse model and in clinical samples derived from canine or human HF patients. Cardiac-restricted knockdown of the hnRNPL homolog in Drosophila revealed systolic dysfunction and reduced life span. This study demonstrates a conserved cross-species role of hnRNPL in regulating heart function. Supported by ORIP (K01OD028205) and NHLBI.