Selected Grantee Publications
SALL1 Enforces Microglia-Specific DNA Binding and Function of SMADs to Establish Microglia Identity
Fixsen et al., Nature Immunology. 2023.
https://doi.org/10.1038/s41590-023-01528-8
Microglia function is thought to play a role in neurodevelopmental, psychiatric, and neurodegenerative diseases. Using knockout mice, investigators explored functional interactions between spalt-like transcription factor 1 (SALL1) and SMAD4, which demonstrated that interactions are mediated by a conserved microglia-specific SALL1 super-enhancer and result in direct activation of regulatory elements. The concerted interactions induce a microglia lineage determining program of gene expression. These findings indicate that expression of SALL1 and associated genes could contribute to phenotypes of aging and neurodegenerative diseases. Supported by ORIP (S10OD026929), NIA, NIMH, and NINDS.
Osteopontin Is an Integral Mediator of Cardiac Interstitial Fibrosis in Models of Human Immunodeficiency Virus Infection
Robinson et al., The Journal of Infectious Diseases. 2023.
https://www.doi.org/10.1093/infdis/jiad149
HIV infection is associated with increased risk of cardiovascular disease. Plasma osteopontin (Opn) is correlated with cardiac pathology, but more work is needed to understand the underlying mechanisms driving cardiac fibrosis. Researchers explored this topic using mouse embryonic fibroblasts, male macaques, and humanized mice of both sexes. They reported the accumulation of Opn in the heart with simian immunodeficiency virus infection. Systemic inhibition of Opn can prevent HIV-associated interstitial fibrosis in the left ventricle. These findings suggest that Opn could be a potential target for adjunctive therapies to reduce cardiac fibrosis in people with HIV. Supported by ORIP (P51OD011104), NIAID, NHLBI, NIMH, and NINDS.
Simultaneous Evaluation of Treatment Efficacy and Toxicity for Bispecific T-Cell Engager Therapeutics in a Humanized Mouse Model
Yang et al., The FASEB Journal. 2023.
https://faseb.onlinelibrary.wiley.com/doi/10.1096/fj.202300040R
Immuno-oncology–based therapies are an evolving powerful treatment strategy that targets the immune system and harnesses it to kill tumor cells directly. Investigators describe the novel application of a humanized mouse model that can simultaneously evaluate the efficacy of bispecific T cell engagers to control tumor burden and the development of cytokine release syndrome. The model also captures variability in responses for individual patients. Supported by ORIP (R24OD026440), NIAID, NCI, and NIDDK.
A LGR5 Reporter Pig Model Closely Resembles Human Intestine for Improved Study of Stem Cells in Disease
Schaaf et al., The FASEB Journal. 2023.
https://faseb.onlinelibrary.wiley.com/doi/10.1096/fj.202300223R
The constant epithelial regeneration in the intestine is the sole responsibility of intestinal epithelial stem cells (ISCs), which reside deep in the intestinal crypt structures. To effectively study ISCs, tools to identify this cell population are necessary. This study validates ISC isolation in a new porcine Leucine Rich Repeat Containing G Protein–Coupled Receptor 5 (LGR5) reporter line and demonstrates the use of these pigs as a novel colorectal cancer model. Overall, this novel porcine model provides critical advancement to the field of translational gastrointestinal research. Supported by ORIP (R21OD019738, K01OD019911), NCI, and NIDDK.
Brain Microglia Serve as a Persistent HIV Reservoir Despite Durable Antiretroviral Therapy
Tang et al., The Journal of Clinical Investigation. 2023.
https://www.doi.org/10.1172/JCI167417
Brain microglia are likely to play a role in rebound viremia following the cessation of antiretroviral therapy, but more work is needed to fully understand HIV persistence in the central nervous system (CNS). The investigators developed a protocol to isolate highly pure populations of brain myeloid cells and microglia from the tissues of male rhesus macaques, as well as from rapid autopsies of men and women with HIV. Their observations support the concept that brain microglia are a stable reservoir of quiescent infection. Thus, this work provides a physiologically relevant platform for studies of the biology of CNS reservoirs. Supported by ORIP (P51OD011132), NIAID, and NIMH.
Lymph-Node-Based CD3+ CD20+ Cells Emerge From Membrane Exchange Between T Follicular Helper Cells and B Cells and Increase Their Frequency Following Simian Immunodeficiency Virus Infection
Samer et al., Journal of Virology. 2023.
https://www.doi.org/10.1128/jvi.01760-22
CD4+ T follicular helper cells are known to persist during antiretroviral therapy (ART) and have been identified as key targets for viral replication and persistence. Researchers identified a lymphocyte population that expresses CD3 (i.e., T cell lineage marker) and CD20 (i.e., B cell lineage marker) on the cellular surface in lymphoid tissues from rhesus macaques of both sexes and humans of male and female sexes. In macaques, the cells increased following simian immunodeficiency virus infection, were reduced with ART, and increased in frequency after ART interruption. These cells represent a potential area for future therapeutic strategies. Supported by ORIP (P51OD011132, U42OD011023), NIAID, NCI, NIDDK, NIDA, NHLBI, and NINDS.
Giardia Hinders Growth by Disrupting Nutrient Metabolism Independent of Inflammatory Enteropathy
Giallourou et al., Nature Communications. 2023.
https://www.nature.com/articles/s41467-023-38363-2
Giardia lamblia is one of the most common intestinal pathogens among children in low- and middle-income countries. Investigators performed translational investigations using the Malnutrition and Enteric Diseases (MAL-ED) male and female cohort, as well as mice of both sexes, to identify mechanistic pathways that might explain Giardia-induced effects on early childhood growth. They identified signatures in the urinary metabolome of young children, suggesting that host growth restriction during infection is mediated by dysregulated amino acid metabolism. Supported by ORIP (P40OD010995), NIAID, and NIDDK.
CD8+ T Cells Promote HIV Latency by Remodeling CD4+ T Cell Metabolism to Enhance Their Survival, Quiescence, and Stemness
Mutascio et al., Immunity. 2023.
https://www.doi.org/10.1016/j.immuni.2023.03.010
An HIV reservoir persists following antiretroviral therapy, representing the main barrier to an HIV cure. Using a validated in vitro model, investigators explored the mechanism by which CD8+ T cells promote HIV latency and inhibit latency reversal in HIV-infected CD4+ T cells. They reported that CD8+ T cells favor the establishment of HIV latency by modulating metabolic, stemness, and survival pathways that correlate with the downregulation of HIV expression and promote HIV latency. In future studies, comparative analyses may provide insight into common molecular mechanisms in the silencing of HIV expression by CD8+ T cells and macrophages, which can be applied to new intervention strategies that target the HIV reservoir. Supported by ORIP (P51OD011132, S10OD026799), NIAID, NIDDK, NIDA, NHLBI, and NINDS.
Hematopoietic Stem Cells Preferentially Traffic Misfolded Proteins to Aggresomes and Depend on Aggrephagy to Maintain Protein Homeostasis
Chua et al., Cell Stem Cell. 2023.
https://pubmed.ncbi.nlm.nih.gov/36948186/
Investigators studied the mechanism of hematopoietic stem cells (HSCs) being dependent on managing proteostasis. Their findings demonstrated that HSCs preferentially depend on aggrephagy, a form of autophagy, to maintain proteostasis. When aggrephagy is disabled, HSCs compensate by increasing proteasome activity, but proteostasis is ultimately disrupted as protein aggregates accumulate and HSC function is impaired. The investigators also showed that Bag3 deficiency blunts aggresome formation in HSCs, resulting in protein aggregate accumulation, myeloid-biased differentiation, and diminished self-renewal activity, thus demonstrating Bag3 as a regulator of HSC proteostasis. HSC aging is associated with loss of aggresomes and reduced autophagic flux. Protein degradation pathways are thus configured in young-adult HSCs to preserve proteostasis and fitness but become dysregulated during aging. Supported by ORIP (S10OD032316, S10OD021831), NCI, and NIDDK.
Longitudinal Characterization of Circulating Extracellular Vesicles and Small RNA During Simian Immunodeficiency Virus Infection and Antiretroviral Therapy
Huang et al., AIDS. 2023.
https://www.doi.org/10.1097/QAD.0000000000003487
Antiretroviral therapy is effective for controlling HIV infection but does not fully prevent early aging disorders or serious non-AIDS events among people with HIV. Using pigtail and rhesus macaques (sex not specified), researchers profiled extracellular vesicle small RNAs during different phases of simian immunodeficiency virus infection to explore the potential relationship between extracellular vesicle–associated small RNAs and the infection process. They reported that average particle counts correlated with infection, but the trend could not be explained fully by virions. These findings raise new questions about the distribution of extracellular vesicle RNAs in HIV latent infection. Supported by ORIP (U42OD013117), NIDA, NIMH, NIAID, NCI, and NINDS.