Biology subjects

Eckert, A.

Publications and source records attributed to Eckert, A..

4 recordsLinked to original sources

bioRxiv2021

Variation in gene expression patterns across a conifer hybrid zone highlights the architecture of adaptive evolution under novel selective pressures

O_LIVariation in gene expression among natural populations are key contributors to adaptive evolution. Understanding the architecture underlying adaptive trait evolution provides insights into the adaptive potential of populations exposed to novel selective pressures. C_LIO_LIWe investigated patterns and processes driving trait differentiation under novel climatic conditions by combining common garden experiments with transcriptome-wide datasets obtained from Pinus strobiformis - Pinus flexilis hybrid zone populations. C_LIO_LIWe found strong signals of genotype-environment interactions at the individual transcript and the co-expression module level, a marked influence of drought related variables on adaptive evolution and an environment dependent influence of P. flexilis ancestry on survival. Using co-expression network connectivity as a proxy for pleiotropy we highlight that adaptive transcripts were pleiotropic across both gardens and modules with strong population differentiation exhibited lower preservation across gardens. C_LIO_LIOur work highlights the utility of integrating transcriptomics with space-for-time substitution studies to evaluate the adaptive potential of long-lived species. We conclude by suggesting that the combination of pleiotropic trait architectures and substantial genetic variation may enable long-lived forest tree species to respond to rapid shift in climatic conditions. C_LI

evolutionary biology↗

bioRxiv2021

Mutant huntingtin crosses the neuromuscular junction and causes transmission-selective pathological alterations in huntingtin expressing myotubes

A potential explanation for the spatiotemporal accumulation of pathological lesions in the brain of patients with neurodegenerative protein misfolding diseases (PMDs) is cell-to-cell transmission of aggregation-prone, misfolded proteins. Little is known about central to peripheral transmission and its contribution to pathology. We show that transmission of Huntingtons disease- (HD-) associated mutant HTT exon 1 (mHTTEx1) occurs across the neuromuscular junctions in human iPSC cultures and in vivo in wild-type mice. We found that transmission is an active and dynamic process, that happens prior to aggregate formation and is regulated by synaptic activity. Furthermore, we find that transmitted mHTTEx1 causes HD-relevant pathology at a molecular and functional level in human muscle cells, even in the presence of ubiquitous expression mHTTEx1. With this work we uncover a casual-link between mHTTEx1 synaptic transmission and pathology, highlighting the therapeutic potential in blocking toxic protein transmission in PMDs.

neuroscience↗

bioRxiv2021

Effects of learning and escitalopram administration on serum BDNF levels, a randomised placebo-controlled trial

BackgroundThe brain-derived neurotrophic factor (BDNF) has been implicated in processes essential for neuroplasticity. Learning and serotonin reuptake inhibitors (SSRI) foster neuronal reorganization, a mechanism potentially related to BDNF. This study aims to assess the effects of associative learning and escitalopram on serum BDNF (sBDNF) levels, to gain further knowledge on their dynamic interplay. MethodsFor three weeks, 37 participants performed one of two associative learning paradigms with either emotional or semantic content daily. During a subsequent three-week period of reversal learning, subjects either received escitalopram (10mg per day) or placebo. Before and after each learning period sBDNF values were assessed. Citalopram plasma levels were measured at the last time point. Linear mixed effects models (LME) and partial Spearmans rank and Pearson correlations were used for statistical analyses. ResultsOne-way LME resulted in a significant effect of time during the first learning period over both groups (p<0.01). Two-way LME revealed a significant interaction effect of the emotional content learning group and time (p=0.02). Three-way LME (time x reversal learning group x substance) showed no significant effects (all p> 0.05). Furthermore, correlation between citalopram and sBDNF level after three weeks of escitalopram administration exhibit a negative trend (partial Pearson correlation: r=-0.30, p=0.05; partial Spearmans rank: r=-0.22, p=0.15). ConclusionThe results suggest that three weeks of associative emotional content learning affect sBDNF levels, while subsequently assessed citalopram plasma and sBDNF levels tend to correlate negatively. Key PointsO_LIEmotional learning may affect serum BDNF levels in healthy human subjects C_LIO_LIBlood levels of citalopram and serum BDNF exhibit a negative correlation C_LI

neuroscience↗

bioRxiv2020

Allele-specific endogenous tagging and quantitative analysis of β-catenin in colon cancer cells

Wnt signaling plays important roles in development, homeostasis, and tumorigenesis. Mutations in {beta}-catenin that activate Wnt signaling have been found in colorectal and hepatocellular carcinomas. However, the dynamics of wild-type and mutant forms of {beta}-catenin are not fully understood. Here, we genome-engineered fluorescently tagged alleles of the endogenous {beta}-catenin in a colorectal cancer cell line. Wild-type and oncogenic mutant alleles were tagged with different fluorescent proteins, enabling the analysis of both variants in the same cell. We analyzed the properties of both {beta}-catenin alleles using immunoprecipitation, immunofluorescence and fluorescence correlation spectroscopy approaches, revealing distinctly different biophysical properties. In addition, activation of Wnt signaling by treatment with a GSK3{beta} inhibitor or a truncating APC mutation modulated the wild-type allele to mimic the properties of the mutant {beta}-catenin allele. The one-step tagging strategy demonstrates how genome engineering can be employed for the parallel functional analysis of different genetic variants.

genetics↗