Glycogen synthase kinase 3 beta (GSK-3beta) has a central role in Alzheimer's disease (AD). Selective inhibitors which avoid tau hyperphosphorylation may represent an effective therapeutical approach to the AD pharmacotherapy and other neurodegenerative disorders. Here, we describe the synthesis, biological evaluation, and SAR of the small heterocyclic thiadiazolidinones (TDZD) as the first non-ATP competitive inhibitor of GSK-3beta. Their synthesis is based on the reactivity of sulfenyl chlorides. In GSK-3beta assays, TDZD derivatives showed IC(50) values in the micromolar range, whereas in other protein kinases assays they were devoid of any inhibitory activity. SAR studies allowed the identification of the key structural features. Finally, a possible enzymatic binding mode is proposed.

Glycogen synthase kinase 3 (GSK-3) was initially described as a key enzyme involved in glycogen metabolism, but is now known to regulate a diverse array of cell functions. Two forms of the enzyme, GSK-3alpha and GSK-3beta, have been previously identified. Small molecules inhibitors of GSK-3 may, therefore, have several therapeutic uses, including the treatment of neurodegenerative diseases, diabetes type II, bipolar disorders, stroke, cancer, and chronic inflammatory disease. As there is lot of recent literature dealing with the involvement of GSK-3 in the molecular pathways of different diseases, this review is mainly focused on the new GSK-3 inhibitors discovered or specifically developed for this enzyme, their chemical structure, synthesis, and structure-activity relationships, with the aim to provide some clues for the future optimization of these promising drugs.

As animals develop, tissue bending contributes to shape the organs into complex three-dimensional structures. However, the architecture and packing of curved epithelia remains largely unknown. Here we show by means of mathematical modelling that cells in bent epithelia can undergo intercalations along the apico-basal axis. This phenomenon forces cells to have different neighbours in their basal and apical surfaces. As a consequence, epithelial cells adopt a novel shape that we term “scutoid”. The detailed analysis of diverse tissues confirms that generation of apico-basal intercalations between cells is a common feature during morphogenesis. Using biophysical arguments, we propose that scutoids make possible the minimization of the tissue energy and stabilize three-dimensional packing. Hence, we conclude that scutoids are one of nature's solutions to achieve epithelial bending. Our findings pave the way to understand the three-dimensional organization of epithelial organs.