Elena Diez Cecilia, PhD, MBA

Urea transporter A (UT-A) isoforms encoded by the Slc14a2 gene are expressed in kidney tubule epithelial cells, where they facilitate urinary concentration. UT-A1 inhibition is predicted to produce a unique salt-sparing diuretic action in edema and hyponatremia. Here we report the discovery of 1,2,4-triazoloquinoxalines and the analysis of 37 synthesized analogues. The most potent compound, 8ay, containing 1,2,4-triazolo[4,3-a]quinoxaline-substituted benzenesulfonamide linked by an aryl ether… Show more

Urea transporter A (UT-A) isoforms encoded by the Slc14a2 gene are expressed in kidney tubule epithelial cells, where they facilitate urinary concentration. UT-A1 inhibition is predicted to produce a unique salt-sparing diuretic action in edema and hyponatremia. Here we report the discovery of 1,2,4-triazoloquinoxalines and the analysis of 37 synthesized analogues. The most potent compound, 8ay, containing 1,2,4-triazolo[4,3-a]quinoxaline-substituted benzenesulfonamide linked by an aryl ether, rapidly and reversibly inhibited UT-A1 urea transport by a noncompetitive mechanism with IC50 ≈ 150 nM; the IC50 was ∼2 μM for the related urea transporter UT-B encoded by the Slc14a1 gene. Molecular modeling suggested a putative binding site on the UT-A1 cytoplasmic domain. In vitro metabolism showing quinoxaline ring oxidation prompted the synthesis of metabolically stable 7,8-difluoroquinoxaline analogue 8bl, which when administered to rats produced marked diuresis and reduced urinary osmolality. 8bl has substantially improved UT-A1 inhibition potency and metabolic stability compared with prior compounds. Show less

There are no disease modifying agents for the treatment of Alzheimer’s disease (AD). Pathologically, AD is associated with the misfolding of two peptides: beta-amyloid (plaques) and tau (tangles). Methods: Using large-scale computer simulations, we modelled the misfolding of both beta-amyloid and tau, identifying a common conformational motif (CCM; i.e. an abnormal peptide shape), present in both beta-amyloid and tau, that promotes their misfolding. We screened a library of 11.8 million… Show more

There are no disease modifying agents for the treatment of Alzheimer’s disease (AD). Pathologically, AD is associated with the misfolding of two peptides: beta-amyloid (plaques) and tau (tangles). Methods: Using large-scale computer simulations, we modelled the misfolding of both beta-amyloid and tau, identifying a common conformational motif (CCM; i.e. an abnormal peptide shape), present in both beta-amyloid and tau, that promotes their misfolding. We screened a library of 11.8 million compounds against this in silico model of protein misfolding, identifying three novel molecular classes of putative therapeutics as anti-protein misfolding agents. We synthesized approximately 400 new chemical entity drug-like molecules in each of these three classes (i.e. 1200 potential drug candidates). These were comprehensively screened in a battery of five in vitro protein oligomerization assays. Selected compounds were next evaluated in the APP/PS1 doubly transgenic mouse model of AD. Results: Two new classes of molecules were identified with the ability to block the oligomerization of both beta-amyloid and tau. These compounds are drug-like with good pharmacokinetic properties and are brain-penetrant. They exhibit excellent efficacy in transgenic mouse models. Conclusion: Computer aided drug design has enabled the discovery of novel drug-like molecules able to inhibit both tau and beta-amyloid misfolding.
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As part of our ongoing search to identify "endogenous
anti-Alzheimer’s molecules" within the human brain we have focussed
on indoleamine-2,3-dioxygenase [IDO] and tryptophan [trp]. Although
the essential amino acid trp can be metabolised via different pathways,
a major route is the kynurenine pathway; IDO is the first enzyme of
the pathway and is strongly stimulated by inflammatory molecules,
particularly within the innate immune system. Various immunohistochemistry
studies… Show more

As part of our ongoing search to identify "endogenous
anti-Alzheimer’s molecules" within the human brain we have focussed
on indoleamine-2,3-dioxygenase [IDO] and tryptophan [trp]. Although
the essential amino acid trp can be metabolised via different pathways,
a major route is the kynurenine pathway; IDO is the first enzyme of
the pathway and is strongly stimulated by inflammatory molecules,
particularly within the innate immune system. Various immunohistochemistry
studies have demonstrated that the density of IDO-immunopositive
cells is significantly higher in both human brain with
Alzheimer’s disease [AD] and AD mice brain, suggesting that IDOmediated
activation of trp catabolism may be involved in amyloid aggregation
and in neurofibrillary tangle formation. Accordingly, we sought to
design trp analogues as possible anti-protein misfolding agents. Show less