Biology subjects

Kashiwagi, C. M.

Publications and source records attributed to Kashiwagi, C. M..

3 recordsLinked to original sources

bioRxiv2024

Prenatal Arsenic Exposure and Gene Expression in Fetal Liver, Heart, Lung, and Placenta

Prenatal arsenic exposure has been linked to a myriad of negative health effects. There is relatively little insight into the mechanisms and signaling alterations across different fetal organs that drive long-term immune-related issues following prenatal arsenic exposure. Therefore, the effects of this exposure window on gene expression in the liver, placenta, heart, and lung of gestation day (GD) 18 C57BL/6 mouse fetuses were investigated. From two weeks prior to mating until tissue collection at GD18, mice were exposed to 0 or 100 ppb sodium (meta) arsenite in drinking water. Genes of interest were analyzed by RT-qPCR, complemented with untargeted Agilent 44K microarray analysis. Data cleanup and analysis was performed in RStudio. Differentially expressed mRNAs were queried in the String Database and using Cytoscape to create interaction networks and identify significantly enriched biological pathways. A total of 251, 165, 158, and 41 genes were significantly altered in the liver, placenta, heart, and lung, respectively, when treated samples were compared to controls. Many altered pathways were immune-related, supporting prior research. Most notably, gene expression of Gbp3, a key player in the cellular response to interferon gamma, was found to be reduced in placentas of female fetuses exposed to arsenic compared to controls (p=0.0762). ImpactThis is the first study comparing alterations in gene expression across multiple organs following prenatal exposure to environmentally relevant levels of arsenic. These findings, elucidating the multi-organ impact of prenatal arsenic exposure on predominantly immune-related pathways, further our mechanistic understanding of the long-term health effects observed in early-life arsenic-exposed populations.

pharmacology and toxicology↗

bioRxiv2022

Lipidomic profiling reveals age-dependent changes in complex plasma membrane lipids that regulate neural stem cell aging

The aging brain exhibits a decline in the regenerative populations of neural stem cells (NSCs), which may underlie age-associated defects in sensory and cognitive functions1-6. While mechanisms that restore old NSC function have started to be identified7-23, the role of lipids - especially complex lipids - in NSC aging remains largely unclear. Using lipidomic profiling by mass spectrometry, we identify age-related lipidomic signatures in young and old quiescent NSCs in vitro and in vivo. These analyses reveal drastic changes in several complex membrane lipid classes, including phospholipids and sphingolipids in old NSCs. Moreover, poly-unsaturated fatty acids (PUFAs) strikingly increase across complex lipid classes in quiescent NSCs during aging. Age-related changes in complex lipid levels and side chain composition are largely occurring in plasma membrane lipids, as revealed by lipidomic profiling of isolated plasma membrane vesicles. Experimentally, we find that aging is accompanied by modifications in plasma membrane biophysical properties, with a decrease in plasma membrane order in old quiescent NSCs in vitro and in vivo. To determine the functional role of plasma membrane lipids in aging NSCs, we performed genetic and supplementation studies. Knockout of Mboat2, which encodes a phospholipid acyltransferase, exacerbates age-related lipidomic changes in old quiescent NSCs and impedes their ability to activate. As Mboat2 expression declines with age, Mboat2 deficiency may drive NSC decline during aging. Interestingly, supplementation of plasma membrane lipids derived from young NSCs boosts the ability of old quiescent NSCs to activate. Our work could lead to lipid-based strategies for restoring the regenerative potential of NSCs in old individuals, which has important implications for countering brain decline during aging.

molecular biology↗

bioRxiv2021

In vitro and in vivo CRISPR-Cas9 screens reveal drivers of aging in neural stem cells of the brain

Aging impairs the ability of neural stem cells to transition from quiescence to activation (proliferation) in the adult mammalian brain. Neural stem cell (NSC) functional decline results in decreased production of new neurons and defective regeneration upon injury during aging1-9, and this is exacerbated in Alzheimers disease10. Many genes are upregulated with age in NSCs3, 11-13, and the knockout of some of these boosts old NSC activation and rejuvenates aspects of old brain function14-18. But systematic functional testing of genes in old NSCs - and more generally in old cells - has not been done. This has been a major limiting factor in identifying the most promising rejuvenation interventions. Here we develop in vitro and in vivo high-throughput CRISPR-Cas9 screening platforms to systematically uncover gene knockouts that boost NSC activation in old mice. Our genome-wide screening pipeline in primary cultures of young and old NSCs identifies over 300 gene knockouts that specifically restore old NSC activation. Interestingly, the top gene knockouts are involved in glucose import, cilium organization and ribonucleoprotein structures. To determine which gene knockouts have a rejuvenating effect for the aging brain, we establish a scalable CRISPR-Cas9 screening platform in vivo in old mice. Of the 50 gene knockouts we tested in vivo, 23 boost old NSC activation and production of new neurons in old brains. Notably, the knockout of Slc2a4, which encodes for the GLUT4 glucose transporter, is a top rejuvenating intervention for old NSCs. GLUT4 protein expression increases in the stem cell niche during aging, and we show that old NSCs indeed uptake [~]2-fold more glucose than their young counterparts. Transient glucose starvation increases the ability of old NSCs to activate, which is not further improved by knockout of Slc2a4/GLUT4. Together, these results indicate that a shift in glucose uptake contributes to the decline in NSC activation with age, but that it can be reversed by genetic or external interventions. Importantly, our work provides scalable platforms to systematically identify genetic interventions that boost old NSC function, including in vivo in old brains, with important implications for regenerative and cognitive decline during aging.

neuroscience↗