Brown and beige adipocytes are enriched in mitochondria with uncoupling protein-1 (UCP1) to generate heat instead of ATP contributing to healthy energy balance. There are few human cellular models to reveal regulatory networks in adipocyte browning and key targets for enhancing thermogenesis in obesity. The Simpson-Golabi-Behmel syndrome (SGBS) preadipocyte line has been a useful tool to study human adipocyte biology. Here we report that SGBS cells, which are comparable to subcutaneous adipose-derived stem cells, carry an FTO risk allele. Upon sustained PPARγ stimulation or irisin (a myokine released in response to exercise) treatment, SGBS cells differentiated into beige adipocytes exhibiting multilocular lipid droplets, high UCP1 content with induction of typical browning genes ( Cidea, Elovl3 ) and the beige marker Tbx1 . The autocrine mediator BMP7 led to moderate browning with the upregulation of the classical brown marker Zic1 instead of Tbx1 . Thermogenesis potential resulted from PPARγ stimulation, irisin and BMP7 can be activated in UCP1-dependent and the beige specific, creatine phosphate cycle mediated way. The beige phenotype, maintained under long-term (28 days) conditions, was partially reversed by withdrawal of PPARγ ligand. Thus, SGBS cells can serve as a cellular model for both white and sustainable beige adipocyte differentiation and function.

Brown and beige adipocytes contribute significantly to the regulation of whole body energy expenditure and systemic metabolic homeostasis not exclusively by thermogenesis through mitochondrial uncoupling. Several studies have provided evidence in rodents that brown and beige adipocytes produce a set of adipokines ("batokines") which regulate local tissue homeostasis and have beneficial effects on physiological functions of the entire body. We observed elevated secretion of Interleukin (IL)-6, IL-8 and monocyte chemoattractant protein (MCP)-1, but not tumor necrosis factor alpha (TNFα) or IL-1β pro-inflammatory cytokines, by ex vivo differentiating human beige adipocytes (induced by either PPARγ agonist or irisin) compared to white. Higher levels of IL-6, IL-8 and MCP-1 were released from human deep neck adipose tissue biopsies (enriched in browning cells) than from subcutaneous ones. IL-6 was produced in a sustained manner and mostly by the adipocytes and not by the undifferentiated progenitors. Continuous blocking of IL-6 receptor by specific antibody during beige differentiation resulted in downregulation of brown marker genes and increased morphological changes that are characteristic of white adipocytes. The data suggest that beige adipocytes adjust their production of IL-6 to reach an optimal level for differentiation in the medium enhancing browning in an autocrine manner.

Administration of second-generation antipsychotic drugs (SGAs) often leads to weight gain and consequent cardio-metabolic side effects. We observed that clozapine but not six other antipsychotic drugs reprogrammed the gene expression pattern of differentiating human adipocytes ex vivo, leading to an elevated expression of the browning marker gene UCP1, more and smaller lipid droplets and more mitochondrial DNA than in the untreated white adipocytes. Laser scanning cytometry showed that up to 40% of the differentiating single primary and Simpson–Golabi–Behmel syndrome (SGBS) adipocytes had the characteristic morphological features of browning cells. Furthermore, clozapine significantly upregulated ELOVL3, CIDEA, CYC1, PGC1A and TBX1 genes but not ZIC1 suggesting induction of the beige-like and not the classical brown phenotype. When we tested whether browning induced by clozapine can be explained by its known pharmacological effect of antagonizing serotonin (5HT) receptors, it was found that browning cells expressed 5HT receptors 2A, 1D, 7 and the upregulation of browning markers was diminished in the presence of exogenous 5HT. Undifferentiated progenitors or completely differentiated beige or white adipocytes did not respond to clozapine administration. The clozapine-induced beige cells displayed increased basal and oligomycin-inhibited (proton leak) oxygen consumption, but these cells showed a lower response to cAMP stimulus as compared with control beige adipocytes indicating that they are less capable to respond to natural thermogenic anti-obesity cues. Our data altogether suggest that novel pharmacological stimulation of these masked beige adipocytes can be a future therapeutic target for the treatment of SGA-induced weight gain.

Increased permeability of the epithelial and endothelial cell layers results in the onset of pathogenic mechanisms. In both cell types, cell–cell connections play a regulatory role in altering membrane permeability. The aim of this study was to investigate the modulating effect of anthocyanin-rich extract (AC) on TJ proteins in inflammatory Caco-2 and HUVEC monolayers. Distribution of Occludin and zonula occludens-1 (ZO-1) were investigated by immunohistochemical staining and the protein levels were measured by flow cytometry. The mRNA expression was determined by quantitative real-time PCR. The transepithelial electrical resistance (TEER) values were measured during a permeability assay on HUVEC cell culture. As a result of inflammatory induction by TNF-α, redistribution of proteins was observed in Caco-2 cell culture, which was reduced by AC treatment. In HUVEC cell culture, the decrease in protein and mRNA expression was more dominant during inflammatory induction, which was compensated for by the AC treatment. Overall, AC positively affected the expression of the examined cell-binding structures forming the membrane on both cell types.

The antimicrobial effect of chitosan and synthetic chitosan derivatives has been confirmed on many Gram-positive and Gram-negative bacteria and fungi. The tests were carried out on pathogenic microorganisms, so the mechanism and concentration dependence of the inhibitory effect of chitosan were revealed. We conducted our tests on a probiotic strain, Lactobacillus plantarum. Commercially available chitosan derivatives of different molecular weights were added to L. plantarum suspension in increasing concentrations. The minimum inhibitory concentration (MIC) value of chitosan was determined and confirmed the viability decreasing effect at concentrations above the MIC with a time-kill assay. The release of bacterium cell content was measured at 260 nm after treatment with 0.001–0.1% concentration chitosan solution. An increase in the permeability of the cell membrane was observed only with the 0.1% treatment. The interaction was also investigated by zeta potential measurement, and the irreversible interaction and concentration dependence were established in all concentrations. The interaction of fluorescein isothiocyanate (FITC) labeled low molecular weight chitosan and bacterial cells labeled with membrane dye (FM® 4–64) was confirmed by confocal microscopy. In conclusion, the inhibitory effect of chitosan was verified on a probiotic strain, which is an undesirable effect in probiotic preparations containing chitosan additives, while the inhibitory effect experienced with pathogenic strains is beneficial.