Overexpression the KCNJ3, a gene that encodes subunit 1 of G-protein activated inwardly rectifying K+ channel (GIRK1) in the primary tumor has been found to be associated with reduced survival times and increased lymph node metastasis in breast cancer patients. In order to survey possible tumorigenic properties of GIRK1 overexpression, a range of malignant mammary epithelial cells, based on the MCF-7 cell line that permanently overexpress different splice variants of the KCNJ3 gene (GIRK1a, GIRK1c, GIRK1d and as a control, eYFP) were produced. Subsequently, selected cardinal neoplasia associated cellular parameters were assessed and compared. Adhesion to fibronectin coated surface as well as cell proliferation remained unaffected. Other vital parameters intimately linked to malignancy, i.e. wound healing, chemoinvasion, cellular velocities / motilities and angiogenesis were massively affected by GIRK1 overexpression. Overexpression of different GIRK1 splice variants exerted differential actions. While GIRK1a and GIRK1c overexpression reinforced the affected parameters towards malignancy, overexpression of GIRK1d resulted in the opposite. Single channel recording using the patch clamp technique revealed functional GIRK channels in the plasma membrane of MCF-7 cells albeit at very low frequency. We conclude that GIRK1d acts as a dominant negative constituent of functional GIRK complexes present in the plasma membrane of MCF-7 cells, while overexpression of GIRK1a and GIRK1c augmented their activity. The core component responsible for the cancerogenic action of GIRK1 is apparently presented by a segment comprising aminoacids 235–402, that is present exclusively in GIRK1a and GIRK1c, but not GIRK1d (positions according to GIRK1a primary structure). The current study provides insight into the cellular and molecular consequences of KCNJ3 overexpression in breast cancer cells and the mechanism upon clinical outcome in patients suffering from breast cancer.

Dietary polyphenols, which are present in Aronia melanocarpa, have been associated with various beneficial effects on human health including antioxidant, antiviral, and anti-inflammatory activities. We aimed to investigate the immunomodulatory effects of aronia juice polyphenols in a randomized placebo-controlled human intervention study and cell culture experiments. A total of 40 females were asked to consume either 200 mL of aronia juice or a placebo drink for six weeks and were investigated again after a washout period of another six weeks. We observed that only half of the participants tolerated the aronia juice well (Vt) and the other half reported complaints (Vc). The placebo (P) was generally tolerated with one exception (p = 0.003). Plasma polyphenol levels increased significantly in Vt after the intervention (p = 0.024) but did neither in P nor in Vc. Regulatory T cell (Treg) frequencies remained constant in Vt and P during the intervention, whereas Tregs decreased in Vc (p = 0.018). In cell culture, inhibiting effects of ferulic acid (p = 0.0005) and catechin (p = 0.0393) on the differentiation of Tregs were observed as well as reduced activation of CD4-T cells in ferulic acid (p = 0.0072) and aronia juice (p = 0.0163) treated cells. Interestingly, a CD4⁺CD25⁻FoxP3⁺ cell population emerged in vitro in response to aronia juice, but not when testing individual polyphenols. In conclusion, our data strengthen possible individual hormetic effects, the importance of the food matrix for bioactivity, and the need for further investigations on possible impacts of specific physiological features such as the gut microbiota in the context of personalized nutrition.

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).

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.

TGF-β family ligands are key regulators of dendritic cell (DC) differentiation and activation. Epidermal Langerhans cells (LCs) require TGF- β family signaling for their differentiation and canonical TGF-β1 signaling secures a non-activated LC state. LCs reportedly control skin inflammation and are replenished from peripheral blood monocytes, which also give rise to pro-inflammatory monocyte-derived DCs (moDCs). Among all the miRNAs differentially expressed in LC vs moDCs, we observed miR-424 to be strongly induced during moDC differentiation from monocytes. We discovered that miR-424 is required for moDC differentiation from human and murine precursor cells in vitro and for inflammation-associated moDC in vivo . Mechanistically we found that low levels of miR-424 facilitate TGF-β1-dependent LC differentiation at the expense of moDC differentiation. Loss of miR-424 in monocyte/DC precursors resulted in the induction of TGF-β pathway. Therefore, miR-424 plays a decisive role in anti-inflammatory LC vs pro-inflammatory moDC differentiation from monocytes, and its repression allows TGF-β ligands to promote LC differentiation. Short summary: Monocytes give rise to two distinct DC subsets in skin inflammation, exhibiting opposite roles in inflammation. This study identified miR-424(322) as a molecular switch controlling pro-inflammatory (moDC) vs anti-inflammatory LC subset differentiation by modulating TGF-β signaling.