SR-BI Undergoes Cholesterol-stimulated Transcytosis to the Bile Canaliculus in Polarized WIF-B Cells
Bibliographic record
Abstract
The scavenger receptor BI (SR-BI) is highly expressed in hepatocytes, where it mediates the uptake of lipoprotein cholesterol, promotes the secretion of cholesterol into bile, and protects against atherosclerosis. Despite a strong correlation between the hepatic expression of SR-BI and biliary cholesterol secretion, little is known about SR-BI trafficking in response to changes in sterol availability. Using a well characterized polarized hepatocyte cell model, WIF-B, we determine that in cholesterol-depleted cells, SR-BI is extensively located on the basolateral surface, where it can access circulating lipoproteins. However, in response to cholesterol loading, SR-BI undergoes a slow transcytosis to the apical bile canaliculus independently of lipoprotein binding and new protein synthesis. In cholesterol-replete WIF-B cells, SR-BI that resides on the canalicular membrane is dynamically associated with defined microdomains and does not rapidly recycle to and from the subapical or basolateral regions. Taken together, these data demonstrate that hepatic SR-BI transcytosis is regulated by cholesterol and suggest that SR-BI has a stationary function on the bile canaliculus.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".