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Record W7010443308

Identification of molecular mechanisms that may contribute to the antidepressant effect of St. John's wort extract Ze 117

2024· dissertation· en· W7010443308 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

aboutThe title or abstract carries a Canadian signal from the geographic lexicon.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

Venuebonndoc (University of Bonn) · 2024
Typedissertation
Languageen
FieldNeuroscience
TopicStress Responses and Cortisol
Canadian institutionsnot available
Fundersnot available
KeywordsMembraneReceptorGlucocorticoid receptorMechanism of actionCellMembrane fluidityCell membraneIn vitroMode of action
DOInot available

Abstract

fetched live from OpenAlex

Chronic stress is one of the factors that contribute to the development and maintenance of depression. Previous studies have shown that the treatment of cultured cells with the natural stress hormone cortisol, but also with synthetic relatives such as dexamethasone, led to a change in their plasma membrane fluidity. Furthermore, it is assumed that this can result in altered properties of membrane receptors that are suspected to be responsible for the development of depression and thus represent targets for its treatment. St. John's wort extract (SJW) Ze 117 has long been used as an alternative to synthetic antidepressants to treat mild to moderate depression. It has also been shown to counteract the glucocorticoid mediated effect on the plasma membrane fluidity of various cell types. Part of its molecular mode of action may therefore be due to an effect on the cellular lipid composition and thus on the properties of plasma membranes and receptor systems embedded within. The prior aim of the present work was to identify cellular target structures that may contribute to the antidepressant effect of Ze 117 using C6 and HEK cell based assays, including fluorescence anisotropy, RT-qPCR, proteomics, lipid analysis, β-arrestin 2 recruitment, and single particle tracking (SPT). <br /> The results show that dexamethasone has an increasing effect on the fluidity of C6 cell plasma membranes which was counteracted by the co-treatment with Ze 117. The performed experiments revealed that this is not due to an effect on the enzyme stearoyl-CoA-desaturase (SCD) but rather on cellular cholesterol synthesis. This was reflected in changed cellular cholesterol contents. While Ze 117 increased the cholesterol content by 42.5 %, dexamethasone reduced cholesterol levels similar to simvastatin. It was also shown that alterations in cholesterol levels affect the interaction of the intracellular protein β-arrestin 2 with the membranous G protein-coupled receptor (GPCR) 5-HT<sub>1A</sub>. Moreover, SPT experiments revealed that Ze 117 and other membrane fluidity affecting treatments alter the diffusion state occupancy of SNAP-tagged 5-HT<sub>1A</sub> receptor. <br /> In summary, Ze 117 affects membrane fluidity through cholesterol metabolism, impacting 5-HT<sub>1A</sub> receptor signal transduction and mobility, suggesting a new antidepressant mechanism.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.009
Threshold uncertainty score0.997

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.011
GPT teacher head0.248
Teacher spread0.237 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it