Browsing by Author "Djikić, Dragoslava (42061363200)"

The pancreas appears to be a major source of ghrelin during fetal development, but the ontogeny of ghrelin cells in the human pancreas and their developmental relationship with α- and β-cells remain largely unknown. In the present study, we examined the dynamics of ghrelin cell growth, colocalization of ghrelin with major pancreatic hormones and defined the similarities and differences among developmental patterns of ghrelin-, glucagon- and insulin-expressing cells in the human pancreas. To this end, paraffin-embedded pancreatic tissue sections from human embryos and fetuses were assessed by immunohistochemistry. Ghrelin-positive cells were first detected in the pancreas of 11-week-old fetuses. With advancing gestational age, both ghrelin- and glucagon-expressing cells were increasingly observed at the periphery of the developing islets, whereas insulin-containing cells were typically found in the islet core. Double immunohistochemistry showed that ghrelin-expressing cells were clearly separate from insulin-, somatostatin- and pancreatic polypeptide-containing cells. In contrast, cells coexpressing ghrelin and glucagon were sporadically detected during both the early and late fetal periods. Furthermore, morphometric analysis revealed a similar trend in the volume density of ghrelin- and glucagon-positive cells, and a contrasting pattern in β-cell density at specific time points during the development of the human pancreas. This study demonstrates that the developmental pattern of ghrelin cells, although clearly distinct, is quite similar to that of glucagon-expressing cells. The obtained findings indicate a close lineage relationship between these cell populations, a functional relationship between their secretory products and an auto/paracrine mode of ghrelin-glucagon interaction in pancreatic development. © 2012 S. Karger AG, Basel.

Purpose: Previously, the family of S100A proteins has been found to be associated with inflammation and myelopoiesis and to be able to induce or support myeloproliferation during chronic inflammation. Here, we studied the inflammatory myeloid-related proteins S100A4, S100A8, S100A9 and S100A12 in myeloproliferative neoplasms (MPNs) in order to assess the involvement of chronic inflammation in the pathogenesis of MPN. Methods: We analyzed the S100A4, S100A8, S100A9 and S100A12 mRNA and protein levels in the bone marrow and circulation of 140 patients with MPN and 15 healthy controls using Western blotting, microarray-based mRNA expression profiling and ELISA assays, respectively. In addition we performed functional studies on the proliferation-related AKT and ERK1/2 signaling pathways in MPN-derived granulocytes using Western blotting and proteomic analyses. Results: We found that the S100A mRNA levels were increased in MPN patient-derived circulatory CD34+ cells, and that their protein expression levels were also augmented in their granulocytes and bone marrow stroma cells, depending on the JAK2V617F mutation allele burden. We also found that calreticulin (CALR) mutations were related to reduced S100A8 plasma levels in primary myelofibrosis (PMF). The S100A8 plasma levels were found to be increased in MPN, the S100A9 plasma levels in PMF and essential thrombocythemia (ET), and the S100A12 plasma levels in polycythemia vera (PV). These S100A plasma levels showed a positive correlation with the systemic inflammation marker IL-8, as well as with the numbers of leukocytes and thrombocytes, depending on the JAK2V617F mutation status. Additionally, we found that heterodimeric S100A8/9 can inhibit the AKT pathway in MPN-derived granulocytes mediated by the Toll-like receptor 4 (TLR4), depending on the CALR mutation status. Conversely, we found that blocking of the receptor for advanced glycation end products (RAGE) increased the S100A8/9-mediated inhibition of AKT signaling in the MPN-derived granulocytes. Moreover, we found that heterodimeric S100A8/9 generally induced TLR4-mediated ERK1/2 dephosphorylation proportionally to the JAK2V617F mutation allele burden. TLR4/RAGE blocking prevented the S100A8/9-mediated inhibition of ERK1/2 phosphorylation in PV. Conclusions: From our data we conclude that the S100A8 and S100A9 granulocyte and plasma levels are increased in MPN patients, along with inflammation markers, depending on their JAK2V617F mutation allele burden. We also found that S100A8/9-mediated inhibition of the proliferation-related AKT and ERK1/2 signaling pathways can be decreased by CALR mutation-dependent TLR4 blocking and increased by RAGE inhibition in MPN. © 2018, International Society for Cellular Oncology.

Purpose: Previously, the family of S100A proteins has been found to be associated with inflammation and myelopoiesis and to be able to induce or support myeloproliferation during chronic inflammation. Here, we studied the inflammatory myeloid-related proteins S100A4, S100A8, S100A9 and S100A12 in myeloproliferative neoplasms (MPNs) in order to assess the involvement of chronic inflammation in the pathogenesis of MPN. Methods: We analyzed the S100A4, S100A8, S100A9 and S100A12 mRNA and protein levels in the bone marrow and circulation of 140 patients with MPN and 15 healthy controls using Western blotting, microarray-based mRNA expression profiling and ELISA assays, respectively. In addition we performed functional studies on the proliferation-related AKT and ERK1/2 signaling pathways in MPN-derived granulocytes using Western blotting and proteomic analyses. Results: We found that the S100A mRNA levels were increased in MPN patient-derived circulatory CD34+ cells, and that their protein expression levels were also augmented in their granulocytes and bone marrow stroma cells, depending on the JAK2V617F mutation allele burden. We also found that calreticulin (CALR) mutations were related to reduced S100A8 plasma levels in primary myelofibrosis (PMF). The S100A8 plasma levels were found to be increased in MPN, the S100A9 plasma levels in PMF and essential thrombocythemia (ET), and the S100A12 plasma levels in polycythemia vera (PV). These S100A plasma levels showed a positive correlation with the systemic inflammation marker IL-8, as well as with the numbers of leukocytes and thrombocytes, depending on the JAK2V617F mutation status. Additionally, we found that heterodimeric S100A8/9 can inhibit the AKT pathway in MPN-derived granulocytes mediated by the Toll-like receptor 4 (TLR4), depending on the CALR mutation status. Conversely, we found that blocking of the receptor for advanced glycation end products (RAGE) increased the S100A8/9-mediated inhibition of AKT signaling in the MPN-derived granulocytes. Moreover, we found that heterodimeric S100A8/9 generally induced TLR4-mediated ERK1/2 dephosphorylation proportionally to the JAK2V617F mutation allele burden. TLR4/RAGE blocking prevented the S100A8/9-mediated inhibition of ERK1/2 phosphorylation in PV. Conclusions: From our data we conclude that the S100A8 and S100A9 granulocyte and plasma levels are increased in MPN patients, along with inflammation markers, depending on their JAK2V617F mutation allele burden. We also found that S100A8/9-mediated inhibition of the proliferation-related AKT and ERK1/2 signaling pathways can be decreased by CALR mutation-dependent TLR4 blocking and increased by RAGE inhibition in MPN. © 2018, International Society for Cellular Oncology.