Macrophages in obesity are characterised by increased IL-1ß response to calcium-sensing receptor signals.

OBJECTIVE: Obesity is complicated by inflammatory activation of the innate immune system. Stimulation of the calcium-sensing receptor (CaSR) by extra-cellular calcium ions ([Ca2+]ex) can trigger NLRP3 inflammasome activation and inflammation. We hypothesised, that this mechanism might contribute to the activation of adipose tissue (AT) in obesity, and investigated [Ca2+]ex-induced, CaSR mediated IL-1ß release by macrophages in obesity. METHODS: [Ca2+]ex-induced IL-1ß release was investigated in monocyte-derived macrophages (MDM) generated from peripheral blood of patients with obesity and from normal-weight controls. Visceral and subcutaneous AT biosamples were stimulated with [Ca2+]ex, and IL-1ß release, as well as expression of NLRP3 inflammasome and cytokine genes, was determined. RESULTS: Both MDM and AT readily responded with concentration-dependent IL-1ß release already at low, near physiological concentrations to addition of [Ca2+]ex, which was more than 80 fold higher than the LPS-induced effect. IL-1ß levels induced by [Ca2+]ex were significantly higher not only in MDM from patients with obesity compared to controls, but also in visceral versus subcutaneous AT. This fat-depot difference was also reflected by mRNA expression levels of inflammasome and cytokine genes. CONCLUSIONS: Obesity renders macrophages more susceptible to [Ca2+]ex-induced IL-1ß release and pyroptosis. Increased susceptibility was independent of the response to LPS and circulating CRP arguing against mere pro-inflammatory pre-activation of monocytes. Instead, we propose that CaSR mediated signalling is relevant for the deleterious innate immune activation in obesity.

Perturbation of the Monocyte Compartment in Human Obesity.

Circulating monocytes can be divided into classical (CM), intermediate (IM), and non-classical monocytes (NCM), and the classical monocytes also contain CD56+ monocytes and monocytic myeloid-derived suppressor cells (M-MDSC). The aim of the study was to evaluate the occurrence of the monocyte subpopulations in human obesity. Twenty-seven normal, 23 overweight, and 60 obese individuals (including 17 obese individuals with normal glucose tolerance and 27 with type 2 diabetes) were included into this study. Peripheral blood mononuclear cells were isolated from human blood, and surface markers to identify monocyte subpopulations were analyzed by flow cytometry. Obese individuals had higher numbers of total monocytes, CM, IM, CD56+ monocytes, and M-MDSCs. The number of CM, IM, CD56+ monocytes, and M-MDSCs, correlated positively with body mass index, body fat, waist circumference, triglycerides, C-reactive protein, and HbA1c, and negatively with high-density lipoprotein cholesterol. Individuals with obesity and type 2 diabetes had higher numbers of IM, NCM, and M-MDSCs, whereas those with obesity and impaired glucose tolerance had higher numbers of CD56+ monocytes. In summary, the comprehensive analysis of blood monocytes in human obesity revealed a shift of the monocyte compartment toward pro-inflammatory monocytes which might contribute to the development of low-grade inflammation in obesity, and immune-suppressive monocytes which might contribute to the development of cancer in obesity.

Polo-like kinase 1 inhibition as a new therapeutic modality in therapy of cholangiocarcinoma.

BACKGROUND: Cholangiocarcinoma (CC) is highly resistant to chemotherapy and radiation, and is, therefore, difficult to cure. Polo-like kinases (Plks) are increasingly recognized as key regulators of mitosis, meiosis and cytokinesis. Alterations in PLK1- expression have been brought into relation with tumorigenesis, thus rendering PLK1 suppression an interesting target for tumor therapy. BI 2536, the first compound of the chemical class of dihydropteridinones, is a highly selective and potent inhibitor of PLK1. MATERIALS AND METHODS: Retardation of cell proliferation by BI 2536 was tested in 14 CC cell lines by cell viability assay. Moreover, molecular activity of BI 2536 was investigated by Western blot, flow cytometry and real time- polymerase chain reaction (RT-PCR). Apposition of gemcitabine, 5-fluorouracil (5-FU) and insulin-like growth factor-1 receptor (IGF-1R) retardant NVP-AEW541 was also examined. RESULTS: BI 2536 subdued proliferation in all CC cell lines, however, reaction was stronger in gallbladder carcinoma. Therapy with BI 2536 did not result in a significant change in phosphorylation of histone H3, AKT, and p42/44. However, exposure of cells to this compound caused arrest at the G(2)/M-checkpoint and a surge in apoptosis. Moreover, PLK1 and FOXM1 were concurrently present in all cell lines, proposing a role for their involvement. Use of a mixture of BI 2536 with 5-FU or NVP-AEW541 resulted in synergism, while a mixture with gemcitabine resulted in additive activity. CONCLUSION: These experiments indicate that BI 2536 is effective against CC and increases the potency of 5-FU and NVP-AEW541.