Carotenoids are plant-derived bioactive compounds with antioxidant properties and well-established roles in human health. Circulating carotenoid concentrations are widely used as an objective biomarker of fruit and vegetable intake; however, their assessment by high-performance liquid chromatography (HPLC) requires invasive sampling and laboratory infrastructure. Reflection spectroscopy-based devices, such as the Veggie Meter and Biozoom, offer rapid, noninvasive alternatives for assessing cutaneous carotenoids (CC), but their validity across different body composition profiles remains insufficiently characterized. In this study, plasma carotenoid concentrations quantified by HPLC were compared with CC measurements obtained using the Veggie Meter and Biozoom in 54 healthy women across three study visits (n = 151 observations). Associations between plasma and cutaneous carotenoids were evaluated using Spearman and partial correlation analyses with adjustment for body fat percentage and were further examined using linear mixed-effects models (LMMs) accounting for repeated measurements including body fat percentage and smoking status as covariates. Total plasma carotenoid concentrations were strongly correlated with CC values measured by Biozoom (rs (151) = 0.697, p < 0.001) and Veggie Meter (rs (151) = 0.650, p < 0.001). Provitamin A carotenoids exhibited the strongest associations, whereas lutein and lycopene showed weaker correlations. All associations remained statistically significant after adjusting for body fat percentage and smoking status. Both plasma and cutaneous carotenoid levels were inversely associated with BMI and obesity-related measures (all p < 0.0033, after Bonferroni correction for multiple comparisons). These findings support the use of reflection spectroscopy-based cutaneous carotenoid measurements as valid, noninvasive nutritional biomarkers of fruit and vegetable-derived carotenoid exposure. Such tools may facilitate dietary assessment and monitoring in nutrition research, clinical practice, and public health settings, provided that body composition is considered when interpreting results.

Hydrogel-based scaffolds are central to three-dimensional (3D) epithelial culture systems, yet commonly used matrices such as Matrigel® suffer from batch variability, undefined composition, and limited translational relevance. Here, we comparatively evaluated an animal-free nanocellulose hydrogel (GrowDex®) and Matrigel® in a hybrid vascularized intestinal-chorioallantoic membrane (CAM) model. Pre-cultured epithelial-immune constructs (Caco-2/HT29-MTX with immune components) were embedded in both matrices and grafted onto the CAM for 72 h. Histological and immunohistochemical analyses revealed that nanocellulose-based constructs maintained more cohesive epithelial coverage, improved scaffold integrity, and yielded a more continuous cytokeratin-positive layer at the scaffold-CAM interface. In contrast, Matrigel® constructs frequently exhibited heterogeneous epithelial distribution and central discontinuities. While both matrices enabled CAM engraftment, the chemically defined nanocellulose hydrogel demonstrated enhanced structural robustness during in vivo exposure and histological processing. These findings highlight the suitability of standardized nanocellulose hydrogels for reproducible scaffold-based epithelial models in vascularized environments.

Langerhans cells (LCs) are long-lived, tissue-resident mononuclear phagocytes that form dense networks in stratified epithelia and migrate to draining lymph nodes to maintain immune tolerance. LC development and their immature epithelial identity depend on TGF-β family signaling; however, the transcriptional effectors downstream of this pathway remain incompletely defined. In this study, we identify the basic helix-loop-helix transcription factor BHLHE40 (basic helix-loop-helix E40)/DEC1 (differentially expressed in chondrocytes 1) as a positive regulator of LC lineage commitment and epithelial identity. Transcriptomic profiling of an in vitro LC differentiation system from human hematopoietic progenitors revealed the rapid induction of BHLHE40 downstream of TGF-β1-TGFBR1/ALK5 signaling. Lentiviral knockdown and overexpression demonstrated that BHLHE40 promotes LC differentiation, whereas its loss skews cells toward a monocyte and monocyte-derived dendritic cell fate. The loss of BHLHE40 reduced phosphorylation of SMAD2/3; impaired the expression of RUNX3; and decreased the expression of epithelial markers, including E-cadherin, EpCAM, TROP2, and AXL. In human skin, BHLHE40 is broadly expressed in steady-state LCs but is downregulated in psoriatic LCs. Supporting a conserved role in vivo, Bhlhe40-deficient mice exhibit disruption of the epidermal LC network, whereas LC-specific heterozygous mice show reduced LC accumulation in skin-draining lymph nodes. Together, these findings identify BHLHE40 as a previously unrecognized transcriptional regulator connecting canonical TGF-β1 signaling to epithelial LC homeostasis.

Background : In atopic dermatitis (AD), the skin is colonized by high levels of Staphylococcus aureus (SA), while levels of the commensal Staphylococcus epidermidis (SE) are reduced. Levels of SA correlate with the severity of the disease, while transplantation of SE into the skin can ameliorate AD. Objectives : It is hypothesized that the underlying mechanism is supported by Langerhans cells (LCs) which sense a shift in the microbiome and then either continue to perpetuate the disease (with SA) or to act as anti-inflammatory agents, ameliorating the inflammation (with SE). However, many different experimental protocols generating very different results have made the literature on this topic complex and hard to understand. Methods : In this study, we specifically tested human, embryonic stem cell-derived LCs and measured their reactions to SA and SE. We directly compared co-cultures exposed to living SA and SE and to heat-killed bacteria. We analyzed the gene expression of the LCs with qPCR and flow cytometry, the secreted cytokines via ELISA, and their downstream effect on T cells. Results : Our data show that exposure to living SA causes LCs to mature; in turn, this activates a T-cell response of cytokine secretions resembling the inflammatory phenotype observed in AD patients. Meanwhile, SE-primed LCs do not activate T cells, but instead act as anti-inflammatory agents by secreting high levels of IL-10. Importantly, this difference can only be observed in living bacteria. LCs react to heat-killed SE as pro-inflammatory agents, as they do to SA (albeit slightly weaker). Conclusions : Using living bacteria is absolutely crucial when performing experiments to reflect the in vivo situation. Our results expand on the work of others and contribute to the ongoing investigation of interactions of the skin and its microbiome. Why was the study undertaken ? Numerous studies have observed that SE not only correlates with less severe AD, but can ameliorate the disease. This study was undertaken to further investigate the immunological mechanisms related to this effect. What does this study add ? Our data shows that SE modifies T-cell reactions via LCs. Importantly, only living SE has this anti-inflammatory effect; heat-killed SE instead has a pro-inflammatory effect similar to that of S. aureus . What are the implications of this study for the understanding of skin physiology and pathology and/or disease management ? The skin microbiome plays a key role in AD, but at the heart of AD pathophysiology are T cells. We present further evidence that the missing link between the microbiome and the T cells is in fact the LCs. List of abbreviations: AD : Atopic dermatitis; APC : Antigen-presenting cell; DC : Dendritic cell; LC : Langerhans cell; mo-LC : Monocyte-derived Langerhans cell; LN : Lymph nodes; PBMCs : Peripheral blood mononuclear cells; SA : Staphylococcus aureus ; SE : Staphylococcus epidermidis .

IntroductionOn the outermost edge of the body a dense network of dendritic cells (DCs), the so-called Langerhans cells (LCs), represents the first immune barrier. The establishment and maintenance of this epidermal network is dependent on the cytokine transforming growth factor-β1 (TGF-β1) expressed by keratinocytes (KC) and LCs. We recently identified a crucial downstream effector of TGF-β1, the receptor tyrosine kinase Axl. Axl belongs to the TAM receptor family, which also includes Tyro3 and Mer, and is activated through the vitamin K-dependent ligands Gas6 and Protein S.MethodsWe have now established that TGF-β1 dependent in vitro human LC generation from CD34+ progenitor cells can be enhanced by Axl over-expression.ResultsAdditionally, we supplemented vitamin K into serum-free human LC generation cultures in order to activate the endogenous ligands Gas6 and Protein S. Vitamin K exhibited supportive effects on LC differentiation and LC-associated gene expression. The vitamin K antagonist warfarin on the other hand, hindered efficient LC differentiation. Blocking antibodies against Axl abrogated the positive effect of vitamin K on LC differentiation. Lastly, vitamin K downregulated the immune activation marker CD86 during LC differentiation and blocked the upregulation of CD86 during LC activation in vitro, in an Axl independent manner.DiscussionTaken together, we provide evidence for the supportive role of vitamin K in regulating skin immunity.

Arthropods are ancient vectors of infectious disease that alter the immune environment of the skin during feeding. The epidermis and its immune sentinels, including Langerhans cells, are critical for protection against ectoparasitic arthropods such as ticks. Here, we investigate how human Langerhans cells respond to clinical and experimental tick bites and concomitant infection with the tick-borne bacterium Borrelia burgdorferi. Using imaging, migration assays, immune spheroid models, and single-cell transcriptomic analysis of patient samples, we show that tick bites and tick saliva reprogram Langerhans cells to increase migration into lymphatic tissues, adopt a tolerogenic state marked by specific transcriptional programs, reduced ability to induce pro-inflammatory helper T cells, and enhanced promotion of type 2 and regulatory T cell responses. This shift dampens protective immunity and helps explain how ticks and their pathogens evade host defense and achieve efficient transmission.

Retinoic acid (RA) plays a key role in mucosal immune regulation and tolerance, with implications for inflammatory bowel disease (IBD). However, its effects have not been extensively studied in humanized in vitro models that recapitulate epithelial–immune interactions. We established a 3D in vitro small intestinal model composed of three epithelial cell types, naïve CD4+ T cells, and monocyte/dendritic cell (M/DC) precursors derived from CD34+ umbilical cord blood hematopoietic stem/progenitor cells. The epithelial microenvironment strongly suppressed monocyte/DC differentiation and T cell activation, indicating a regulatory role of epithelial-derived signals. Retinoic acid (RA) priming of M/DC precursors induced CD103+CD11b+Sirp1α− regulatory DCs and promoted a shift from naive to memory-type T cells. Upon addition of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β), the model mimicked an inflamed intestinal state, resulting in CD14+CD16+ inflammatory monocytes and increased T cell activation (CD25+CD69+). RA-primed DCs modestly counterbalanced T cell activation and IBD-like responses, even under inflammatory conditions. Flow cytometry and clustering analysis revealed distinct immune cell phenotypes depending on RA exposure and cytokine context. This model provides a reproducible and physiologically relevant human system to study RA-mediated immune programming in the intestinal mucosa and may support the development of novel therapeutic strategies for IBD and related inflammatory conditions. Statistical differences were evaluated using ANOVA with Tukey’s post-hoc test (n = 4; p < 0.05).

The gut microbiome contributes to chronic inflammatory responses in ulcerative colitis (UC), but molecular mechanisms and disease-relevant effectors remain unclear. Here we analyze the pro-inflammatory properties of colonic fluid obtained during colonoscopy from UC and control patients. In patients with UC, we find that the pelletable effector fraction is composed mostly of bacterial extracellular vesicles (BEVs) that exhibit high IgA-levels and incite strong pro-inflammatory responses in IgA receptor-positive (CD89+) immune cells. Biopsy analyses reveal higher infiltration of CD89+ immune cells in the colonic mucosa from patients with UC than control individuals. Further studies show that IgA-coated BEVs, but not host-derived vesicles nor soluble IgA, are potent activators of pro-inflammatory responses in CD89+ cells. IgA-coated BEVs also exacerbate intestinal inflammation in a dextran sodium sulfate colitis model using transgenic mice expressing human CD89. Our data thus implicate a link between IgA-coated BEVs and intestinal inflammation via CD89+ immune cells, and also hint a potential new therapeutic target for UC.

Dendritic cell (DC) progenitors adapt their transcriptional program during development, generating different subsets. How chromatin modifications modulate these processes is unclear. Here, we investigate the impact of histone deacetylation on DCs by genetically deleting histone deacetylase 1 (HDAC1) or HDAC2 in hematopoietic progenitors and CD11c-expressing cells. While HDAC2 is not critical for DC development, HDAC1 deletion impairs pro-pDC and mature pDC generation and affects ESAM+cDC2 differentiation from tDCs and pre-cDC2s, whereas cDC1s are unchanged. HDAC1 knockdown in human hematopoietic cells also impairs cDC2 development, highlighting its crucial role across species. Multi-omics analyses reveal that HDAC1 controls expression, chromatin accessibility, and histone acetylation of the transcription factors IRF4, IRF8, and SPIB required for efficient development of cDC2 subsets. Without HDAC1, DCs switch immunologically, enhancing tumor surveillance through increased cDC1 maturation and interleukin-12 production, driving T helper 1-mediated immunity and CD8+ T cell recruitment. Our study reveals the importance of histone acetylation in DC development and anti-tumor immunity, suggesting DC-targeted therapeutic strategies for immuno-oncology.

Objectives: Aggregation and misfolding of amyloid beta (Af3) and tau proteins, suggested to arise from post-translational modification processes, are thought to be the main cause of Alzheimer 's disease (AD). Additionally, a plethora of evidence exists that links metabolic dysfunctions such as obesity, type 2 diabetes (T2D), and dyslipidemia to the pathogenesis of AD. We thus investigated the combinatory effect of T2D and human glutaminyl cyclase activity (pyroglutamylation), on the pathology of AD and whether astaxanthin (ASX) treatment ameliorates accompanying pathophysiological manifestations. Methods: Male transgenic AD mice, APPxhQC, expressing human APP751 with the Swedish and the London mutation and human glutaminyl cyclase (hQC) enzyme and their non-transgenic (NTG) littermates were used. Both APPxhQC and NTG mice were allocated to 3 groups, control, T2D-control, and T2D-ASX. Mice were fed control or high fat diet + ASX for 13 weeks starting at an age of 11-12 months. High fat diet fed mice were further treated with streptozocin for T2D induction. Effects of genotype, T2D induction, and ASX treatment were evaluated by analysing glycemic readouts, lipid concentration, Af3 deposition, hippocampus-dependent cognitive function and nutrient sensing using immunosorbent assay, ELISA-based assays, western blotting, immuno fluorescence staining, and behavioral testing via Morris water maze (MWM), respectively. Results: APPxhQC mice presented a higher glucose sensitivity compared to NTG mice. T2D-induced brain dysfunction was more severe in NTG compared to the APPxhQC mice. T2D induction impaired memory functions while increasing hepatic LC3B, ABCA1, and p65 levels in NTG mice. T2D induction resulted in a progressive shift of Af3 from the soluble to insoluble form in APPxhQC mice. ASX treatment reversed T2D-induced memory dysfunction in NTG mice and in parallel increased hepatic pAKT while decreasing p65 and increasing cerebral p-S6rp and p65 levels. ASX treatment reduced soluble Af338 and Af340 and insoluble Af340 levels in T2D-induced APPxhQC mice. Conclusions: We demonstrate that T2D induction in APPxhQC mice poses additional risk for AD pathology as seen by increased Af3 deposition. Although ASX treatment reduced Af3 expression in T2D-induced APPxhQC mice and rescued T2D-induced memory impairment in NTG mice, ASX treatment alone may not be effective in cases of T2D comorbidity and AD. m 2024 The Author(s). Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Maintaining the homeostasis of the placental vasculature is of paramount importance for ensuring normal fetal growth and development. Any disruption in this balance can lead to perinatal morbidity. Several studies have uncovered an association between high levels of oxidized cholesterol (oxysterols), and complications during pregnancy, including gestational diabetes mellitus (GDM) and preeclampsia (PE). These complications often coincide with disturbances in placental vascular function. Here, we investigate the role of two oxysterols (7-ketocholesterol, 7β-hydroxycholesterol) in (dys)function of primary fetoplacental endothelial cells (fpEC). Our findings reveal that oxysterols exert a disruptive influence on fpEC function by elevating the production of reactive oxygen species (ROS) and interfering with mitochondrial transmembrane potential, leading to its depolarization. Moreover, oxysterol-treated fpEC exhibited alterations in intracellular calcium (Ca2+) levels, resulting in the reorganization of cell junctions and a corresponding increase in membrane stiffness and vascular permeability. Additionally, we observed an enhanced adhesion of THP-1 monocytes to fpEC following oxysterol treatment. We explored the influence of activating the Liver X Receptor (LXR) with the synthetic agonist T0901317 (TO) on oxysterol-induced endothelial dysfunction in fpEC. Our results demonstrate that LXR activation effectively reversed oxysterol-induced ROS generation, monocyte adhesion, and cell junction permeability in fpEC. Although the effects on mitochondrial depolarization and calcium mobilization did not reach statistical significance, a strong trend towards stabilization of calcium mobilization was evident in LXR-activated cells. Taken together, our results suggest that high levels of systemic oxysterols link to placental vascular dysfunction and LXR agonists may alleviate their impact on fetoplacental vasculature.

In mammalian cells, glycerolipids are mainly synthesized using acyl-CoA-dependent mechanisms. The acyl-CoA-independent transfer of fatty acids between lipids, designated as transacylation reaction, represents an additional mechanism for lipid remodeling and synthesis pathways. Here, we demonstrate that human and mouse phospholipase A2 group IVD (PLA2G4D) catalyzes transacylase reactions using both phospholipids and acylglycerols as substrates. In the presence of monoglycerol and diacylglycerol (MAG and DAG), purified PLA2G4D generates DAG and triacylglycerol, respectively. The enzyme also transfers fatty acids between phospholipids and from phospholipids to acylglycerols. Overexpression of PLA2G4D in COS7 cells enhances the incorporation of polyunsaturated fatty acids into triacylglycerol stores and induces the accumulation of lysophospholipids. In the presence of exogenously added MAG, the enzyme strongly increases cellular DAG formation, while MAG levels are decreased. PLA2G4D is not or poorly detectable in commonly used cell lines. It is expressed in keratinocytes, where it is strongly upregulated by proinflammatory cytokines. Pla2g4d- deficient mouse keratinocytes exhibit complex lipidomic changes in response to cytokine treatment, indicating that PLA2G4D is involved in the remodeling of the lipidome under inflammatory conditions. Transcriptomic analysis revealed that PLA2G4D modulates fundamental biological processes including cell proliferation, differentiation, and signaling. Together, our observations demonstrate that PLA2G4D has broad substrate specificity for fatty acid donor and acceptor lipids, allowing the acyl-CoA-independent synthesis of both phospholipids and acylglycerols. Loss-of-function studies indicate that PLA2G4D affects metabolic and signaling pathways in keratinocytes, which is associated with complex lipidomic and transcriptomic alterations.

Background Aronia melanocarpa is a berry rich in polyphenols known for health benefits. However, the bioavailability of polyphenols has been questioned, and the individual taste acceptance of the fruit with its specific flavor varies. We recently observed substantial differences in the tolerability of aronia juice among healthy females, with half of the individuals tolerating aronia juice without complaints. Given the importance of the gut microbiome in food digestion, we investigated in this secondary analysis of the randomized placebo-controlled parallel intervention study (ClinicalTrials.gov registration: NCT05432362) if aronia juice tolerability was associated with changes in intestinal microbiota and bacterial metabolites, seeking for potential mechanistic insights into the impact on aronia polyphenol tolerance and metabolic outcomes. Results Forty females were enrolled for this 6-week trial, receiving either 100 ml natural aronia juice (verum, V) twice daily or a polyphenol-free placebo (P) with a similar nutritional profile, followed by a 6-week washout. Within V, individuals were categorized into those who tolerated the juice well (Vt) or reported complaints (Vc). The gut microbiome diversity, as analyzed by 16S rRNA gene-based next-generation sequencing, remained unaltered in Vc but changed significantly in Vt. A MICOM-based flux balance analysis revealed pronounced differences in the 40 most predictive metabolites post-intervention. In Vc carbon-dioxide, ammonium and nine O-glycans were predicted due to a shift in microbial composition, while in Vt six bile acids were the most likely microbiota-derived metabolites. NMR metabolomics of plasma confirmed increased lipoprotein subclasses (LDL, VLDL) post-intervention, reverting after wash out. Stool samples maintained a stable metabolic profile. Conclusion In linking aronia polyphenol tolerance to gut microbiota-derived metabolites, our study explores adaptive processes affecting lipoprotein profiles during high polyphenol ingestion in Vt and examines effects on mucosal gut health in response to intolerance to high polyphenol intake in Vc. Our results underpin the importance of individualized hormetic dosing for beneficial polyphenol effects, demonstrate dynamic gut microbiome responses to aronia juice, and emphasize personalized responses in polyphenol interventions. Graphical Abstract DsmAL-oYwbuhyB_vVwEdDj Video Abstract

IntroductionProphylactic strategies to prevent the development of allergies by establishing tolerance remain an unmet medical need. We previously reported that the transfer of autologous hematopoietic stem cells (HSC) expressing the major timothy grass pollen allergen, Phl p 5, on their cell surface induced allergen-specific tolerance in mice. In this study, we investigated the ability of allergen-expressing immune cells (dendritic cells, CD4+ T cells, CD8+ T cells, and CD19+ B cells) to induce allergen-specific tolerance in naive mice and identified CD19+ B cells as promising candidates for allergen-specific cell therapy.MethodsFor this purpose, CD19+ B cells were isolated from Phl p 5-transgenic BALB/c mice and transferred to naive BALB/c mice, pre-treated with a short course of rapamycin and an anti-CD40L antibody. Subsequently, the mice were subcutaneously sensitized three times at 4-week intervals to Phl p 5 and Bet v 1 as an unrelated control allergen. Allergen-expressing cells were followed in the blood to monitor molecular chimerism, and sera were analyzed for Phl p 5- and Bet v 1-specific IgE and IgG1 levels by RBL assay and ELISA, respectively. In vivo allergen-induced lung inflammation was measured by whole-body plethysmography, and mast cell degranulation was determined by skin testing.ResultsThe transfer of purified Phl p 5-expressing CD19+ B cells to naive BALB/c mice induced B cell chimerism for up to three months and prevented the development of Phl p 5-specific IgE and IgG1 antibody responses for a follow-up period of 26 weeks. Since Bet v 1 but not Phl p 5-specific antibodies were detected, the induction of tolerance was specific for Phl p 5. Whole-body plethysmography revealed preserved lung function in CD19+ B cell-treated mice in contrast to sensitized mice, and there was no Phl p 5-induced mast cell degranulation in treated mice.DiscussionThus, we demonstrated that the transfer of Phl p 5-expressing CD19+ B cells induces allergen-specific tolerance in a mouse model of grass pollen allergy. This approach could be further translated into a prophylactic regimen for the prevention of IgE-mediated allergy in humans.

Several subsets of mononuclear phagocytes and DCs (MDC) populate the small intestine (SI), and these cells reportedly exert specialized functions in anti-microbial immunity and tolerance. Given the specialized phenotype of these cells, differing from other MDC family members, including their putative circulating blood precursors, local intestinal factors play key instructive roles in their differentiation. We designed an SI cell culture model composed of three intestinal epithelial cell (IEC) types, including absorptive enterocytes (E cells), antigen delivering microfold (M) cells, and mucus-producing goblet (G) cells plus T lymphocytes and soluble B cell-derived factors. This model was used to study the differentiation fate of CD34+ hematopoietic progenitor cell-derived monocyte/DC precursors. Progeny cells can be analyzed after a 3-week co-culture period, mimicking the physiologic turn-over time of intestinal MDC. A dominant monocyte differentiation pathway was suppressed, in favor of partial differentiation along DC and macrophage pathways, with low percentages of cells acquired DC or macrophage markers. Moreover, E and G cells play opposing roles in CX3CR1+ vs CD103dim cell differentiation, indicating that both together might counter-balance M/DC differentiation. Thus, SI epithelial cells suppress M/DC differentiation, supporting a key role for exogenous factors in M/DC differentiation.

Oxysterols are oxidized cholesterol derivatives whose systemic levels are found elevated in pregnancy disorders such as gestational diabetes mellitus (GDM). Oxysterols act through various cellular receptors and serve as a key metabolic signal, coordinating inflammation. GDM is a condition of low-grade chronic inflammation accompanied by altered inflammatory profiles in the mother, placenta and fetus. Higher levels of two oxysterols, namely 7-ketocholesterol (7-ketoC) and 7β-hydroxycholesterol (7β-OHC), were observed in fetoplacental endothelial cells (fpEC) and cord blood of GDM offspring. In this study, we tested the effects of 7-ketoC and 7β-OHC on inflammation and investigated the underlying mechanisms involved. Primary fpEC in culture treated with 7-ketoC or 7β-OHC, induced the activation of mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NFκB) signaling, which resulted in the expression of pro-inflammatory cytokines (IL-6, IL-8) and intercellular cell adhesion molecule-1 (ICAM-1). Liver-X receptor (LXR) activation is known to repress inflammation. Treatment with LXR synthetic agonist T0901317 dampened oxysterol-induced inflammatory responses. Probucol, an inhibitor of LXR target gene ATP-binding cassette transporter A-1 (ABCA-1), antagonized the protective effects of T0901317, suggesting a potential involvement of ABCA-1 in LXR-mediated repression of inflammatory signaling in fpEC. TLR-4 inhibitor Tak-242 attenuated pro-inflammatory signaling induced by oxysterols downstream of the TLR-4 inflammatory signaling cascade. Taken together, our findings suggest that 7-ketoC and 7β-OHC contribute to placental inflammation through the activation of TLR-4. Pharmacologic activation of LXR in fpEC decelerates its shift to a pro-inflammatory phenotype in the presence of oxysterols.