Cozza G.,University of Padua |
Gianoncelli A.,University of Padua |
Bonvini P.,University of Padua |
Zorzi E.,Fondazione Citta della Speranza |
And 6 more authors.
Casein kinase2 (CK2) is a ubiquitous, essential, and highly pleiotropic protein kinase; its abnormally high constitutive activity is suspected to underlie its pathogenic potential in neoplasia and other relevant diseases. Previously, using different in silico screening approaches, two potent and selective CK2 inhibitors were identified by our group: ellagic acid, a naturally occurring tannic acid derivative (K i=20nM) and 3,8-dibromo-7-hydroxy-4-methylchromen-2-one (DBC, K i=60nM). Comparing the crystallographic binding modes of both ellagic acid and DBC, an X-ray structure-driven merging approach was taken to design novel CK2 inhibitors with improved target affinity. A urolithin moiety is proposed as a possible bridging scaffold between the two known CK2 inhibitors, ellagic acid and DBC. Optimization of urolithinA as the bridging moiety led to the identification of 4-bromo-3,8-dihydroxy-benzo[c]chromen-6-one as a novel, potent and selective CK2 inhibitor, which shows a K i value of 7nM against the protein kinase, representing a significant improvement in affinity for the target compared with the two parent fragments. Two become one: Comparing the crystallographic binding modes of ellagic acid (red) and 3,8-dibromo-7-hydroxy-4-methylchromen-2-one (DBC; blue), an X-ray structure-driven merging approach to the design of novel casein kinase2 (CK2) inhibitors was taken. Using this strategy, a potent and selective urolithin derivative, 4-bromo-3,8-dihydroxy-benzo[c]chromen-6-one was identified, which exhibits a K i value of 7nM against CK2. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Urbani L.,Fondazione Citta della Speranza |
Urbani L.,University of Padua |
Piccoli M.,Fondazione Citta della Speranza |
Piccoli M.,University of Padua |
And 6 more authors.
Satellite cells (SCs) are essential for postnatal muscle growth and regeneration, however, their expansion potential in vitro is limited. Recently, hypoxia has been used to enhance proliferative abilities in vitro of various primary cultures. Here, by isolating SCs from single mouse hindlimb skeletal myofibers, we were able to distinguish two subpopulations of clonally cultured SCs (Low Proliferative Clones - LPC - and High Proliferative Clones - HPC), which, as shown in rat skeletal muscle, were present at a fixed proportion. In addition, culturing LPC and HPC at a low level of oxygen we observed a two fold increased proliferation both for LPC and HPC. LPC showed higher myogenic regulatory factor (MRF) expression than HPC, particularly under the hypoxic condition. Notably, a different myogenic potential between LPC and HPC was retained in vivo: green fluorescent protein (GFP)+LPC transplantation in cardiotoxin-injured Tibialis Anterior led to a higher number of new GFP+muscle fibers per transplanted cell than GFP+HPC. Interestingly, the in vivo myogenic potential of a single cell from an LPC is similar if cultured both in normoxia and hypoxia. Therefore, starting from a single satellite cell, hypoxia allows a larger expansion of LPC than normal O2 conditions, obtaining a consistent amount of cells for transplantation, but maintaining their myogenic regeneration potential. © 2012 Urbani et al. Source