Biology subjects

Foster, C.

Publications and source records attributed to Foster, C..

23 records · Page 2Linked to original sources

bioRxiv2019

Cerebral Metabolic Changes during Visuomotor Adaptation Assessed using Quantitative FMRI

The neural energetics underlying functional brain plasticity have not been thoroughly investigated in the healthy human brain. A better understanding of the blood flow and metabolism changes underlying plasticity will help us to address pathologies in which plasticity is compromised and, with interventions, could be enhanced for patient benefit. Calibrated fMRI was conducted in 20 healthy participants during performance of a serial reaction time task which induces rapid motor adaptation. Regions of interest (ROIs) were defined from areas showing linearly decreasing task-induced BOLD and CBF responses. BOLD, CBF and relative CMRO2 responses were calculated for each block of the task. The flow-metabolism coupling ratio, n, was also calculated for each ROI. Increases from baseline in BOLD, CBF and CMRO2 were observed in multiple brain regions including the motor and sensorimotor cortices, cerebellum and hippocampus during SRT task performance, as well as changes in the response amplitude from early to late task blocks reflecting task adaptation. CMRO2 responses on average decreased faster than BOLD or CBF responses, potentially due to rapid neural adaptation. However, the mean flow-metabolism coupling ratio was not significantly different between ROIs or across blocks. Calibrated fMRI can be used to study energetic changes during learning in the healthy brain and could be used to investigate the vascular and metabolic changes underlying reductions in plasticity in ageing and disease.

neuroscience↗

bioRxiv2018

Molecularly distinct models of zebrafish Myc-induced B cell leukemia

Zebrafish models of T cell acute lymphoblastic leukemia (T-ALL) have been studied for over a decade, but curiously, robust zebrafish B cell ALL (B-ALL) models had not been described. Recently, our laboratories reported two seemingly closely-related models of zebrafish B-ALL. In these genetic lines, the primary difference is expression of either murine or human transgenic c-MYC, each controlled by the zebrafish rag2 promoter. Here, we compare ALL gene expression in both models. Surprisingly, we find that B-ALL arise in different B cell lineages, with ighm+ vs. ighz+ B-ALL driven by murine Myc vs. human MYC, respectively. Moreover, these B-ALL types exhibit signatures of distinct molecular pathways, further unexpected dissimilarity. Thus, despite sharing analogous genetic makeup, the ALL types in each model are markedly different, proving subtle genetic changes can profoundly impact model organism phenotypes. Investigating the mechanistic differences between mouse and human c-MYC in these contexts may reveal key functional aspects governing MYC-driven oncogenesis in human malignancies.

cancer biology↗

bioRxiv2018

Enhanced fitness relates to reduced cerebrovascular reactivity and perfusion in a sample of very healthy older adults

Aging is accompanied by decreased grey matter volume (GMV), cerebral blood flow (CBF), and cerebrovascular reactivity (CVR), where the latter tends to decline the earliest in aging. Enhanced fitness in aging has been related to preservation of GMV and CBF, and in some cases CVR, although there are contradictory relationships reported between CVR and fitness. Therefore, to gain a better understanding of the complex interplay with fitness and GMV, CBF and CVR, it is necessary to study them concurrently. Here, we aimed to disentangle the interactions between these outcomes in healthy older adults. MRI acquisitions collected anatomical, CBF and CVR information in all participants, as well as VO2,max. Results revealed decreased CVR was associated with increased fitness throughout large areas of the cerebral cortex. Within these regions it was found that lower fitness was associated with higher CBF and a slower hemodynamic response to hypercapnia. Overall, results indicate that the relationship between age, cerebral health and cerebral hemodynamics are complex. Future studies should collect other physiological outcomes in parallel with quantitative imaging, such as measures of carbon dioxide sensitivity and autoregulation, to further understand the intricacy of the effects fitness has on the aging brain, and how this may bias quantitative measures of cerebral health.

neuroscience↗

bioRxiv2018

Systems genetic discovery of host-microbiome interactions reveals mechanisms of microbial involvement in disease

The role of the microbiome in health and disease involves complex networks of host genetics, genomics, microbes and environment. Identifying the mechanisms of these interactions has remained challenging. Systems genetics in the laboratory mouse enables data-driven discovery of network components and mechanisms of host-microbial interactions underlying multiple disease phenotypes. To examine the interplay among the whole host genome, transcriptome and microbiome, we mapped quantitative trait loci and correlated the abundance of cecal mRNA, luminal microflora, physiology and behavior in incipient strains of the highly diverse Collaborative Cross mouse population. The relationships that are extracted can be tested experimentally to ascribe causality among host and microbe in behavior and physiology, providing insight into disease. Application of this strategy in the Collaborative Cross population revealed experimentally validated mechanisms of microbial involvement in models of autism, inflammatory bowel disease and sleep disorder.\n\neTOC BlurbHost genetic diversity provides a variable selection environment and physiological context for microbiota and their interaction with host physiology. Using a highly diverse mouse population Bubier et al. identified a variety of host, microbe and potentially disease interactions.\n\nHighlights* 18 significant species-specific QTL regulating microbial abundance were identified\n* Cis and trans eQTL for 1,600 cecal transcripts were mapped in the Collaborative Cross\n* Sleep phenotypes were highly correlated with the abundance of B.P. Odoribacter\n* Elimination of sleep-associated microbes restored normal sleep patterns in mice.

genetics↗

bioRxiv2018

Simultaneous B and T cell acute lymphoblastic leukemias in zebrafish driven by transgenic MYC: implications for oncogenesis and lymphopoiesis

Precursor-B cell acute lymphoblastic leukemia (pre-B ALL) is the most common pediatric cancer, but there are no useful zebrafish pre-B ALL models. We describe the first highly-penetrant zebrafish pre-B ALL, driven by human MYC. Leukemias express B lymphoblast-specific genes and are distinct from T cell ALL (T-ALL)--which these fish also develop. Zebrafish pre-B ALL shares in vivo features and expression profiles with human pre-B ALL, and these profiles differ from zebrafish T-ALL or normal B and T cells. These animals also exhibit aberrant lymphocyte development. As the only robust zebrafish pre-B ALL model and only example where T-ALL also develops, this model can reveal differences between MYC-driven pre-B vs. T-ALL and be exploited to discover novel pre-B ALL therapies.\n\nStatement of significanceWe describe the first robust zebrafish pre-B ALL model in MYC-transgenic animals known to develop T-ALL, revealing the only animal model with both human ALL types. We also describe aberrant multi-lineage lymphopoiesis. This powerful system can be used to study MYC-driven leukemogenesis and discover new pre-B ALL targeted therapies.

cancer biology↗