Search

Ferroptosis is a recently-defined tumor suppression mechanism, but the sensitivity of many tumorigenic cells to ferroptosis is limited by their deficient expression of acyl-CoA synthetase long-chain family member 4 (ACSL4). Here, we report the discovery of a photosensitizer, namely TPCI, which can evoke ACSL4-independent ferroptosis of cancer cells in photodynamic therapy. Through co-localization with 12-lipoxygenase (ALOX12) in multiple subcellular organelles, TPCI activates ALOX12 to generate lipid reactive oxygen species in large quantity and trigger cell ferroptosis. Intriguingly, confining TPCI exclusively in lysosomes switches the cell death from ferroptosis to apoptosis. More strikingly, the ferroptosis mediated by TPCI-induced ALOX12 activation does not require the participation of ACSL4. Therefore, our study identifies TPCI as the first ALOX12 activator to induce ferroptosis independent of ACSL4, which renders a viable therapeutic approach on the basis of distinct ferroptosis of cancer cells, regardless their ACSL4 expressions.

Human milk oligosaccharides (HMOs) have beneficial immune effects but the mechanisms of action are not well understood. Here we study Toll-like receptor (TLR) signaling of the HMOs 2'-FL, 3-FL, 6'-SL, LNT2, and LNnT and their effect on cytokine production in human macrophages. 3-FL activated TLR2 and LNT2 activated all TLRs in a dose-dependent way. In an inhibition assay, 2'-FL, 6'-SL, and LNnT inhibited TLR5 and 7, while 3-FL inhibited TLR5, 7, and 8. 6'-SL showed a synergistic effect on ssRNA40-induced TLR8 activation. In addition, we measured HMO-induced cytokine production in THP1 macrophages. IL-10 and TNF alpha were induced by LNT2, and the effects were NF-kappa B dependent, while the other HMOs had minor effects. The potent effects of LNT2 might be explained by the unique N-acetylglucosamine end that binds to leucine-rich repeats on TLRs. Our data suggest that the effects of HMOs on TLR signaling and immunomodulation of macrophages are HMO-structure dependent.

Scope Human milk oligosaccharides (hMOs) can attenuate inflammation by modulating intestinal epithelial cells, but the mechanisms of action are not well‐understood. Here, the effects of hMOs on tumor necrosis factor‐α (TNF‐α) induced inflammatory events in gut epithelial cells are studied. Methods and results The modulatory effects of 2’‐fucosyllactose, 3‐fucosyllactose (3‐FL), 6’‐sialyllactose, lacto‐N‐tetraose, lacto‐N‐neotetraose (LNnT), lactodifucotetraose (LDFT), and lacto‐N‐triaose (LNT2) on immature (FHs 74 Int) and adult (T84) intestinal epithelial cells with or without TNF‐α are determined. Interleukin‐8 (IL‐8) secretion in FHs 74 Int and T84 are quantified to determine hMO induced attenuation of inflammatory events by ELISA. 3‐FL, LNnT, and LDFT significantly attenuate TNF‐α induced inflammation in FHs 74 Int, while LNT2 induces IL‐8 secretion in T84. In addition, microscale thermophoresis assays and ELISA are used to study the possible mechanisms of interaction between effective hMOs and tumor necrosis factor receptor 1 (TNFR1). 3‐FL, LNnT, and LDFT exert TNFR1 ectodomain shedding while LNnT also shows binding affinity to TNFR1 with a Kd of 900 ± 660 nM. Conclusion The findings indicate that specific hMO types attenuate TNF‐α induced inflammation in fetal gut epithelial cells through TNFR1 in a hMO structure‐dependent fashion suggest possibilities to apply hMOs in management of TNF‐α dependent diseases., Human milk oligosaccharides (hMOs) can attenuate inflammation by modulating intestinal epithelial cells, but the mechanisms are not well‐understood. The anti‐inflammatory effects of different hMOs are tested on tumor necrosis factor‐α induced inflammation in immature and mature intestine epithelial cells. This study shows that the anti‐inflammatory effects of hMOs are structure‐dependent and through interference with tumor necrosis factor receptor 1 signaling.

Human milk is the gold standard for newborn infants. Breast milk not only provides nutrients, it also contains bioactive components that guide the development of the infant's intestinal immune system, which can have a lifelong effect. The bioactive molecules in breast milk regulate microbiota development, immune maturation and gut barrier function. Human milk oligosaccharides (hMOs) are the most abundant bioactive molecules in human milk and have multiple beneficial functions such as support of growth of beneficial bacteria, anti-pathogenic effects, immune modulating effects, and stimulation of intestine barrier functions. Here we critically review the current insight into the benefits of bioactive molecules in mother milk that contribute to neonatal development and focus on current knowledge of hMO-functions on microbiota and the gastrointestinal immune barrier. hMOs produced via genetically engineered microorganisms are now applied in infant formulas to mimic the nutritional composition of breast milk as closely as possible, and their prospects and scientific challenges are discussed in depth.

Background: The intestinal epithelial cells, food molecules, and gut microbiota are continuously exposed to intestinal peristaltic shear force. Shear force may impact the crosstalk of human milk oligosaccharides (hMOs) with commensal bacteria and intestinal epithelial cells. Objectives: We investigated how hMOs combined with intestinal peristaltic shear force impact intestinal epithelial cells and crosstalk with a commensal bacterium. Methods: We applied the Ibidi system to mimic intestinal peristaltic shear force. Caco-2 cells were exposed to a shear force (5 dynes/cm2) for 3 d, and then stimulated with the hMOs, 2'-fucosyllactose (2'-FL), 3-FL, and lacto-N-triose II (LNT2). In separate experiments, Lactobacillus plantarum WCFS1 adhesion to Caco-2 cells was studied with the same hMOs and shear force. Effects were tested on gene expression of glycocalyx-related molecules (glypican 1 [GPC1], hyaluronan synthase 1 [HAS1], HAS2, HAS3, exostosin glycosyltransferase 1 [EXT1], EXT2), defensin β-1 (DEFB1), and tight junction (tight junction protein 1 [TJP1], claudin 3 [CLDN3]) in Caco-2 cells. Protein expression of tight junctions was also quantified. Results: Shear force dramatically decreased gene expression of the main enzymes for making glycosaminoglycan side chains (HAS3 by 43.3% and EXT1 by 68.7%) (P

Human milk oligosaccharide (hMO) is the third-largest solid compound and the most abundant bioactive molecule in human milk. The beneficial effects of hMOs in human milk are broadly acknowledged but the underlying mechanisms are still insufficiently understood. Especially the impact of individual hMOs on the intestinal immune system are still largely unknown. It is important to study now single instead of mixtures of hMOs are used in functional foods and infant formula. In this thesis, we tested different individual hMOs as well as a hMO’s acid hydrolysis product (after passing the stomach) on different cellular systems that represent essential parts of the gastrointestinal immune barrier. We showed that hMOs contribute to the reinforcement of the gastrointestinal immune barrier via direct and indirect modulatory effects, but all in a structure-dependent way. Slight differences in structure have a significant impact on the biological action of an hMO. Specific hMOs can influence growth and function of gut microorganisms. We also identified a new potential receptor for hMOs on gut epithelial cells and proved the importance of cross-talk and the presence of peristaltic movements on impact of hMOs. Our data contribute more knowledge about the structure-function relationship of hMOs, bring new insights for the future hMOs study, and helps for the future design of hMO containing products for the specific target groups.

Scope Human milk oligosaccharides (hMOs) have beneficial effects on intestinal barrier function, but the mechanisms of action are not well understood. Here, the effects of hMOs on goblet cells, which indicate that some hMOs may enhance mucus barrier function through direct modulation of goblet cell function, are studied. Methods and results The modulatory effects of 2′‐fucosyllactose (2′‐FL), 3‐fucosyllactose (3‐FL), lacto‐N‐triaose II (LNT2), and galacto‐oligosaccharides (GOS) on the expression of goblet cell secretory related genes MUC2, TFF3, and RETNLB, and the Golgi‐sulfotransferase genes CHST5 and GAL3ST2 of LS174T are determined by real‐time quantitative RT‐PCR. 3‐FL, LNT2, and GOS‐modulated LS174T gene expression profiles in a dose‐ and time‐dependent manner. In addition, the upregulation of MUC2 is confirmed by immunofluorescence staining. Effects of 2′‐FL, 3‐FL, LNT2, and GOS on gene transcription of LS174T are also assessed during exposure to TNF‐α, IL‐13, or tunicamycin. During TNF‐α challenge, 3‐FL and LNT2 enhance MUC2 and TFF3 gene expression. After IL‐13 exposure, 2′‐FL, 3‐FL, and LNT2 all show upregulating effects on MUC2; 3‐FL and LNT2 also enhance TFF3 expression. LNT2 significantly reverses Tm‐induced downregulation of TFF3, RETNLB, and CHST5. Conclusion The findings indicate that hMOs may enhance mucus barrier function through direct modulation of intestinal goblet cells. Effects are structure‐ and stressor‐dependent., Human milk oligosaccharides (hMOs) are considered to enhance gut barrier function, but the mechanisms of action are not well understood. The effects of 2′‐fucosyllactose, 3‐fucosyllactose, and lacto‐N‐triaose II are tested on goblet cells under different conditions. The results indicate that hMOs enhance mucus barrier function through direct modulation of intestinal goblet cells in a structure‐ and inflammatory‐condition‐dependent manner.

Scope The epithelial glycocalyx development is of great importance for microbial colonization. Human milk oligosaccharides (hMOs) and non-digestible carbohydrates (NDCs) may modulate glycocalyx development. Methods and results The effects of hMOs and NDCs on human gut epithelial cells (Caco2) are investigated by quantifying thickness and area coverage of adsorbed albumin, heparan sulfate (HS), and hyaluronic acid (HA) in the glycocalyx. Effects of hMOs (2 '-FL and 3-FL) and NDCs [inulins with degrees of polymerization (DP) (DP3-DP10, DP10-DP60, DP30-DP60) and pectins with degrees of methylation (DM) (DM7, DM55, DM69)] are tested using immunofluorescence staining at 1 and 5 days stimulation. HMOs show a significant enhancing effect on glycocalyx development but effects are structure-dependent. 3-FL induces a stronger albumin adsorption and increases HS and HA stronger than 2 '-FL. The DP3-DP10, DP30-60 inulins also increase glycocalyx development in a structure-dependent manner as DP3-DP10 selectively increases HS, while DP30-DP60 specifically increases HA. Pectins have less effects, and only increase albumin adsorption. Conclusion Here, it is shown that 2 '-FL and 3-FL and inulins stimulate glycocalyx development in a structure-dependent fashion. This may contribute to formulation of effective hMO and NDC formulations in infant formulas to support microbial colonization and gut barrier function.