Selected Grantee Publications
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- 5 results found
- nia
- niddk
- Stem Cells/Regenerative Medicine
Transcriptomic Analysis of Skeletal Muscle Regeneration Across Mouse Lifespan Identifies Altered Stem Cell States
Walter et al., Nature Aging. 2024.
https://pubmed.ncbi.nlm.nih.gov/39578558
Age-related skeletal muscle regeneration dysfunction is poorly understood. Using single-cell transcriptomics and high-resolution spatial transcriptomics, researchers evaluated factors contributing to age-related decline in skeletal muscle regeneration after injury in young, old, and geriatric male and female mice (5, 20, and 26 months old). Eight immune cell types were identified and associated with age-related dynamics and distinct muscle stem cell states specific to old and geriatric tissue. The findings emphasize the role of extrinsic and intrinsic factors, including cellular senescence, in disrupting muscle repair. This study provides a spatial and molecular framework for understanding regenerative decline and cellular heterogeneity in aging skeletal muscle. Supported by ORIP (F30OD032097), NIA, NIAID, NIAMS, NICHD, and NIDA.
Intestinal Microbiota Controls Graft-Versus-Host Disease Independent of Donor–Host Genetic Disparity
Koyama et al., Immunity. 2023.
https://pubmed.ncbi.nlm.nih.gov/37480848/
Allogeneic hematopoietic stem cell transplantation is a curative therapy for hematopoietic malignancies and non-malignant diseases, but acute graft-versus-host disease (GVHD) remains a serious complication. Specifically, severe gut GVHD is the major cause of transplant-related mortality. Here, the authors show that genetically identical mice, sourced from different vendors, had distinct commensal bacterial compositions, which resulted in significantly discordant severity in GVHD. These studies highlight the importance of pre-transplant microbiota composition for the initiation and suppression of immune-mediated pathology in the gastrointestinal tract, demonstrating the impact of non-genetic environmental determinants to transplant outcome. Supported by ORIP (S10OD028685), NIA, NCI, and NHLBI.
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.
Human Hematopoietic Stem Cell Engrafted IL-15 Transgenic NSG Mice Support Robust NK Cell Responses and Sustained HIV-1 Infection
Abeynaike et al., Viruses. 2023.
https://www.mdpi.com/1999-4915/15/2/365
A major obstacle to human natural killer (NK) cell reconstitution is the lack of human interleukin‑15 (IL-15) signaling, as murine IL-15 is a poor stimulator of the human IL-15 receptor. Researchers show that immunodeficient NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice expressing a transgene encoding human IL-15 (NSG-Tg(IL-15)) have physiological levels of human IL-15 and support long-term engraftment of human NK cells when transplanted with human umbilical cord blood–derived hematopoietic stem cells (HSCs). These mice demonstrate robust and long-term reconstitution with human immune cells but do not develop graft-versus-host disease, allowing long-term studies of human NK cells. The HSC-engrafted mice can sustain HIV-1 infection, resulting in human NK cell responses. This work provides a robust novel model to study NK cell responses to HIV-1. Supported by ORIP (R24OD026440), NIAID, NCI, and NIDDK.
Fructose Stimulated De Novo Lipogenesis Is Promoted by Inflammation
Jelena et al., Nature Metabolism. 2020.
https://pubmed.ncbi.nlm.nih.gov/32839596
Non-alcoholic fatty liver disease (NAFD) affects 30% of adult Americans. While NAFD starts as simple steatosis with little liver damage, its severe manifestation as non-alcoholic steatohepatitis (NASH) is a leading cause of liver failure, cirrhosis, and cancer. Fructose consumption is proposed to increase the risk of hepatosteatosis and NASH. Excessive intake of fructose causes barrier deterioration and low-grade endotoxemia. Using a mouse model, the study examined the mechanism of how fructose triggers these alterations and their roles in hepatosteatosis and NASH pathogenesis. The results demonstrated that microbiota-derived Toll-like receptor (TLR) agonists promote hepatosteatosis without affecting fructose-1-phosphate (F1P) and cytosolic acetyl-CoA. Activation of mucosal-regenerative gp130 signaling, administration of the YAP-induced matricellular protein CCN1 or expression of the antimicrobial peptide Reg3b (beta) counteract fructose-induced barrier deterioration, which depends on endoplasmic-reticulum stress and subsequent endotoxemia. Endotoxin engages TLR4 to trigger TNF production by liver macrophages, thereby inducing lipogenic enzymes that convert F1P and acetyl-CoA to fatty acid in both mouse and human hepatocytes. The finding may be of relevance to several common liver diseases and metabolic disorders. Supported by ORIP (S10OD020025), NCI, NIEHS, NIDDK, NIAID, and NIAAA.