Lipidomics Provides Novel Insights into Understanding the Bee Pollen Lipids Transepithelial Transport and Metabolism in Human Intestinal Cells.

Bee pollen (BP) shows profound gut-protecting potentials. BP lipids (BPLs) mainly composed by phospholipids and polyunsaturated fatty acids might be one of the important contributors, while how BPL exerts gut-protecting effects and is transported through intestinal cell monolayers need to be investigated. Here, we exploited a strategy that combines an UPLC-Q-exactive orbitrap/MS-based lipidomics approach with a human intestinal cell (Caco-2) monolayer transport model, to determine the transepithelial transportation of BPL from Camellia sinensis L. (BPL-Cs), in pathological conditions. The results showed that BPL-Cs protected Caco-2 cells against dextran sulfate sodium (DSS)-induced intestinal barrier dysfunction by improving cell viability, maintaining membrane integrity, increasing tight junctions (ZO-1 and Claudin-1), and eliciting the expressions of antioxidative-related genes ( NQO1 , Nrf2 , Txnrd1 , and GSTA1 ). Lipidomics analysis revealed that DSS suppressed the transport and uptake of most of BPL-Cs including glycerophospholipids, sphingomyelins, and glycosylsphingolipids. Pretreatment with BPL-Cs significantly regulated glycerophospholipid and sphingolipid metabolisms, potentially involved in building permeability barriers and alleviating intestinal oxidative stress. Finally, eight classes of lipids were identified as the potential biomarkers for evaluating DSS-induced Caco-2 cell dysfunctions and BPL-intervened modulation. These findings shed light on the development of BPL as gastrointestinal protective food supplements in the future.