3 research outputs found
Development and bioorthogonal activation of palladium-labile prodrugs of gemcitabine
Bioorthogonal
chemistry has become one of the main driving forces
in current chemical biology, inspiring the search for novel biocompatible
chemospecific reactions for the past decade. Alongside the well-established
labeling strategies that originated the bioorthogonal paradigm, we
have recently proposed the use of heterogeneous palladium chemistry
and bioorthogonal Pd<sup>0</sup>-labile prodrugs to develop spatially
targeted therapies. Herein, we report the generation of biologically
inert precursors of cytotoxic gemcitabine by introducing Pd<sup>0</sup>-cleavable groups in positions that are mechanistically relevant
for gemcitabine’s pharmacological activity. Cell viability
studies in pancreatic cancer cells showed that carbamate functionalization
of the 4-amino group of gemcitabine significantly reduced (>23-fold)
the prodrugs’ cytotoxicity. The <i>N</i>-propargyloxycarbonyl
(<i>N</i>-Poc) promoiety displayed the highest sensitivity
to heterogeneous palladium catalysis under biocompatible conditions,
with a reaction half-life of less than 6 h. Zebrafish studies with
allyl, propargyl, and benzyl carbamate-protected rhodamines confirmed <i>N</i>-Poc as the most suitable masking group for implementing <i>in vivo</i> bioorthogonal organometallic chemistry
Functional modeling in zebrafish demonstrates that the atrial-fibrillation-associated gene GREM2 regulates cardiac laterality, cardiomyocyte differentiation and atrial rhythm
SUMMARY
Atrial fibrillation (AF) is the most common cardiac arrhythmia and carries a significant risk of stroke and heart failure. The molecular etiologies of AF are poorly understood, leaving patients with limited therapeutic options. AF has been recognized as an inherited disease in almost 30% of patient cases. However, few genetic loci have been identified and the mechanisms linking genetic variants to AF susceptibility remain unclear. By sequencing 193 probands with lone AF, we identified a Q76E variant within the coding sequence of the bone morphogenetic protein (BMP) antagonist gremlin-2 (GREM2) that increases its inhibitory activity. Functional modeling in zebrafish revealed that, through regulation of BMP signaling, GREM2 is required for cardiac laterality and atrial differentiation during embryonic development. GREM2 overactivity results in slower cardiac contraction rates in zebrafish, and induction of previously identified AF candidate genes encoding connexin-40, sarcolipin and atrial natriuretic peptide in differentiated mouse embryonic stem cells. By live heart imaging in zebrafish overexpressing wild-type or variant GREM2, we found abnormal contraction velocity specifically in atrial cardiomyocytes. These results implicate, for the first time, regulators of BMP signaling in human AF, providing mechanistic insights into the pathogenesis of the disease and identifying potential new therapeutic targets