Circulating fatty acids (FA) are constitutively taken up by basolateral kidney proximal tubule transporters and are the preferred metabolic substrate. In many chronic kidney diseases, the damaged glomerular filtration barrier permits passage of albumin-bound FA, which are reabsorbed by apical FA transport protein-2 (FATP2). Bilateral FA uptake leads to lipotoxicity and progressive renal function decline, but the relative apical versus basolateral contribution and intracellular mechanisms are not established. Apical or bilateral (but not basolateral) palmitate incubation with human proximal tubule cells stimulated endoplasmic reticulum (ER) stress gene expression, ER stress pathway activation, and ER fragmentation. Apical or bilateral palmitate was associated with reduced lipid droplets, and decreased expression of ER-localized lipid droplet biogenesis transcripts. Inhibition of lipid droplet formation also precipitated ER stress, suggesting diminished sequestration of FA metabolites as the cause. Indeed, C16:0 ceramide was increased in bilateral palmitate-treated cells, and in kidneys from mice that phenocopy progressive diabetic kidney disease. Ceramide synthesis inhibition abrogated ER stress, and transfection with C16:0 ceramide decreased ER membrane fluidity and caused ER stress. We conclude that aberrant filtration and uptake of FA by apical FATP2 exceeded the capacity for lipid droplet incorporation, and led to cytotoxicity from ceramide-induced ER lipid bilayer stress.
Zhiyu Liu, Robert J. Gaivin, Shenaz Khan, Vincent Li, Amal Chaba, Fraser J. Moss, Usman Sabir, Takhar Kasumov, Tingwei Mu, Jeffrey R. Schelling
Usage data is cumulative from June 2026 through June 2026.
| Usage | JCI | PMC |
|---|---|---|
| Text version | 214 | 0 |
| 81 | 0 | |
| Supplemental data | 43 | 0 |
| Citation downloads | 33 | 0 |
| Totals | 371 | 0 |
| Total Views | 371 | |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.