Biology subjects

Emmons, E.

Publications and source records attributed to Emmons, E..

5 recordsLinked to original sources

bioRxiv2026

Temporal transcriptomic remodeling after controlled cortical impact reveals delayed AQP4/SNTA1 expression imbalance associated with ion-homeostatic remodeling

Traumatic brain injury (TBI) is often viewed as a progressively evolving molecular response, yet the molecular and cellular responses that dictate acute TBI may differ fundamentally from those that define the chronically remodeled brain. We integrated temporally-resolved transcriptomic analyses with independent mouse, human, proteomic, and spatial datasets to determine how neural-circuit and astrocyte-homeostatic transcriptional responses reorganize after controlled cortical impact (CCI). In GSE269748, a mouse CCI transcriptomic dataset spanning acute to chronic post-injury timepoints, transcriptomic remodeling was non-monotonic. The number of genes showing large expression changes was greatest at 7 days, with extensive transcriptional changes persisting at 6 months. A more selective astrocytic phenotype emerged at 7 days and persisted at 6 months, with Aqp4 increasing disproportionately relative to Snta1, producing a sustained AQP4/SNTA1 expression imbalance. This imbalance occurred alongside heterogeneous endfoot remodeling and could not be explained by inflammatory stress alone. Among 14 prespecified biological processes, potassium and ion homeostasis showed the most specific and robust association with the AQP4/SNTA1 imbalance after adjustment for broader reactivity and AP-1 activity; this observation remained stable to gene, sample, and injury-model perturbation. Circuit-associated analyses provided complementary context, showing that dopamine recipient changes occurred within broader neurotransmitter system remodeling rather than as a unique signal. Integrative temporal analysis distinguished acute stress-dominant remodeling from delayed astrocyte-homeostatic changes, with AQP4/SNTA1 imbalance and potassium and ion homeostatic remodeling becoming most prominent at later stages. External datasets provided limited contextual support while defining clear limits to generalization. Together, these findings identify delayed AQP4/SNTA1 expression imbalance within potassium and ion homeostatic remodeling as a testable feature of chronic post-traumatic astrocyte biology.

neuroscience↗

bioRxiv2026

Male mice are particularly vulnerable to cognitive impairment following mTBI

Traumatic brain injuries (TBIs) result from impact to or rapid displacement of the brain and can lead to various neurological deficits involving working memory, decision-making, and anxiety. While large-scale effects of brain damage are well-described for more severe TBIs, less is known about the extent and duration of cognitive deficits at the mild level. Interval timing can provide a helpful window into cognition in mice and humans. Interval-timing behavior is impaired in a wide range of neuropsychiatric disease states, such as Parkinsons disease. Furthermore, novel object recognition (NOR) and the Barnes maze (BM) tests are valuable assays for evaluating spatial learning, working memory, and anxiety-like behavior in mice. Here, we employed a weight-drop model of mild TBI (mTBI) to investigate changes in internal cognitive states resulting from mTBI treatment. mTBI mice were not significantly impaired in either interval timing or NOR, but they demonstrated impaired spatial memory in the Barnes Maze. Interestingly, within-sex comparisons revealed impairments in male mTBI mice in the interval-timing task and the NOR, suggesting that male and female mice may be differently affected by mTBIs.

neuroscience↗

bioRxiv2024

Renovating the Barnes maze for mouse models of Dementia with STARR FIELD: A 4-day protocol that probes learning rate, retention and cognitive flexibility.

Land-based spatial mazes are a low-stress method to evaluate learning in rodent models of dementia. By using innate exploratory and hiding behavior, the Barnes maze requires fewer trials, allowing examination of early learning rate and retention, as well as executive and motivational features that can be characteristic of non-amnestic dementias. However, unwanted odor cues may disrupt interpretation of acquisition rate during typical learning trials. We designed and tested our Barnes FIELD protocol (Find the Invisible Exit to Locate the Domicile) to improve reproducibility, allow evaluation of learning trials, and limit experimenter influence. The protocol uses 3D-printed escape shuttles and docking tunnels, allowing mice to exit the maze to the home cage. We show evidence that our shuttles mitigate the possibility of undesired cues. We demonstrate the feasibility of our protocol across several models of cognitive impairment and aging, and develop an additional stage, the STARR (Spatial Training And Rapid Reversal) maze, to better challenge behavioral flexibility. By examining commonly used outcome measures we identify important considerations for interpretation. These insights are used to evaluate several models of cognitive change, including deficits in an Alzheimers disease mouse model, and behavioral flexibility in a model of brainstem dysfunction. This work provides comprehensive instructions to build, perform, and analyze a robust spatial maze that expands the range of behavioral and motivational outcomes that can be identified and screened. Our findings will aid interpretation of traditional protocols, enhance rigor and reproducibility, and provide an updated method to screen for cognitive changes in mice.

neuroscience↗

bioRxiv2021

Experience-related remapping of temporal encoding by striatal ensembles.

Temporal control of action is key for a broad range of behaviors and is disrupted in human diseases such as Parkinsons disease and schizophrenia. A brain structure that is critical for temporal control is the dorsal striatum. Experience and learning can influence dorsal striatal neuronal activity, but it is unknown how these neurons change with experience in contexts which require precise temporal control of movement. We investigated this question by recording from medium-spiny neurons (MSNs) in the dorsal striatum of mice as they gained experience controlling their actions in time. We leveraged an interval timing task optimized for mice which required them to "switch" response ports after enough time had passed without receiving a reward. We report three main results. First, we found that time-related ramping activity and response-related activity increased with more experience. Second, temporal decoding by MSN ensembles improved with experience and was predominantly driven by time-related ramping activity. Finally, we found that some MSNs had differential modulation on error trials. These findings enhance our understanding of dorsal striatal temporal processing by demonstrating how MSN ensembles can evolve with experience. Our results can be linked to temporal habituation and illuminate striatal flexibility during interval timing, which may be relevant for human disease.

neuroscience↗

bioRxiv2021

Single cell proteomics of tumor compartments identifies differential kinase activities defining sensitivity to mTOR-PI3-kinase inhibition

Cancer therapy often results in heterogeneous responses in different metastatic lesions in the same patient. Inter- and intra-tumor heterogeneity in proteomic signaling within the various tumor compartments and its impact on therapy are not well characterized due to the limited sensitivity of single cell proteomic approaches. To overcome this barrier, we applied single cell mass cytometry with a customized 29-antibody panel [against cell states, receptor tyrosine kinases (RTK) and phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR)-, mitogen-activated protein kinase (MAPK)-, and cytokine-signaling] to PTEN-deleted orthotopic prostate cancer xenograft models to measure the evolution of kinase activities in different tumor compartments during metastasis and upon drug treatment. Compared with primary tumors and circulating tumor cells (CTCs), bone metastases but not lung and liver metastases exhibited elevated PI3K/mTOR signaling and RTKs including c-Met protein, which, when suppressed, impaired tumor growth in the bone. Intra-tumoral heterogeneity within tumor compartments also arises from highly proliferative EpCAMhigh epithelial cells with increased PI3K and mTOR kinase activities co-existing with poorly proliferating EpCAMlow mesenchymal populations with reduced kinase activities, findings recapitulated in epithelial and mesenchymal CTC populations in metastatic prostate and breast cancer patients. Increased kinase activity in EpCAMhigh cells rendered them more sensitive to PI3K/mTOR inhibition and drug resistant EpCAMlow populations with reduced kinase activity emerged over time. Taken together, single cell proteomics identified microenvironment- and cell state-dependent activation of kinase networks creating heterogeneity and differential drug sensitivity among and within tumor populations across different sites, defining a new paradigm of drug responses to kinase inhibitors.

cancer biology↗