A water soluble turn-on fluorescent probe for the detection of mercury ions in purely aqueous media a has been developed by appending a water-compatible PEG-unit onto a rhodamine derivative. It has high selectivity for Hg2+ ions and is fairly non-toxic in intercellular studies.
The differentiation of multipotent stem cells toward a pancreatic lineage provides us with an alternative cell-based therapeutic approach to type 1 diabetes and enables us to study pancreas development. The current study aims to study the effect of growth factors such as activin A or nicotinamide, alone and in combinations with the transcription factor, PDX1 (pancreatic and duodenal homeobox-1), on human amnion epithelial cells (hAECs) toward a pancreatic lineage. Ectopic expression of Pdx1 followed by treatment of hAECs with nicotinamide for 4 days resulted in strong induction of pancreatic endoderm and pancreatic progenitor genes, including NKX6.1 and NEUROD1. Pancreatic lineage cells expressing PDX1, SOX17, and RFX6 are derived from Pdx1-transduced hAECs treated with activin A or nicotinamide, but not cells treated with activin A or nicotinamide alone. Our study provides a novel culture protocol for generating pancreas-committed cells from hAECs and reveals an interplay between Pdx1 and activin A/nicotinamide signaling in early pancreatic fate determination.
It has been suggested that the ectopic expression of PDX1, a dominant pancreatic transcription factor, plays a critical role in the developmental programming of the pancreas even from cells of unrelated tissues such as keratinocytes and amniotic fluid stem cells. In this study we have chosen to drive pancreatic development in human amnion epithelial cells by inducing endogenous PDX1 expression. Further, we have investigated the role of Epidermal Growth Factor (EGF) and Poly-L-Ornithine (PLO) on this differentiation process. Human amnion epithelial cells expressed high levels of endogenous PDX1 upon transduction with an adenoviral vector expressing murine Pdx1. Other markers of various stages of pancreatic differentiation such as NKX6.1, SOX17, RFX6, FOXA2, CFTR, NEUROD1, PAX4 and PPY were also expressed upon Pdx1 transduction. Although initial expression of pancreatic progenitor markers was higher in culture conditions lacking EGF, for a sustained and increased expression EGF was required. Culture on PLO further increased the positive impact of EGF. Pancreatic marker expression subsequent to mPdx1 transduction suggests that this approach may facilitate the in vitro differentiation of hAECs into cells of the endocrine pancreas. This result may have important implications in diabetes therapy.
Both type 1 and type 2 diabetes are conditions that are associated with the loss of insulin-producing β-cells within the pancreas. An active research therefore aims at regenerating these β-cells with the hope that they could restore euglycemia. The approaches classically used consist in mimicking embryonic development, making use of diverse cell sources or converting pre-existing pancreatic cells. Despite impressive progresses and promising successes, it appears that we still need to gain further insight into the molecular mechanisms underlying β-cell development. This becomes even more obvious with the emergence of a relatively new field of research, epigenetics. The current review therefore focuses on the latest advances in this field in the context of β-cell (neo-)genesis research.
1 January 2022 in Journal of the Serbian Chemical Society
This paper reports the synthesis and characterization of monomers itaconic anhydride (IA) and tri-O-acetyl-D-glucal (TAG) as well as 4,6-di-O- -acetyl-D-glucal (PSG). The homopolymers and copolymers of IA and TAG were synthesized via free radical copolymerization in bulk, using azobisisobutyronitrile as an initiator with different feed ratios of monomers. Their structural, molecular and thermal characterization was done using 1H-NMR spectroscopy, gel permeation chromatography and differential scanning calorimetry, respectively. The glass transition temperature (Tg) of copolymers was found in the range of 139?145 ?C. The highest Tg was found for IA?TAG2 copolymers, whereas IA?TAG4 copolymer showed lowest Tg. The molecular weight of the copolymers was in the range 5157?5499 g mol-1. The monomer TAG undergoes Ferrier rearrangement in water to give PSG. The antimicrobial activity of IA, TAG, PSG and IA?TAG copolymers was studied using the minimum microbicidal concentration-broth dilution method. TAG, IA and PSG, as well as homopolymer and copolymers of IA and TAG are excellent antimicrobial agents.