Nerve growth factor (NGF) holds a pivotal role in brain development and maintenance, been also involved in the pathophysiology of neurodegenerative diseases. Here, we provide evidence that a novel C17-spiroepoxy steroid derivative, BNN27, specifically interacts with and activates the TrkA receptor of NGF, inducing phosphorylation of TrkA tyrosine residues and down-stream neuronal survival-related kinase signaling. Additionally, BNN27 potentiates the efficacy of low levels of NGF, by facilitating its binding to the TrkA receptors and differentially inducing fast return of internalized TrkA receptors into neuronal cell membranes. Furthermore, BNN27 synergizes with NGF in promoting axonal outgrowth, effectively rescues from apoptosis NGF-dependent and TrkA positive sympathetic and sensory neurons, in vitro, ex vivo and in vivo in NGF null mice. Interestingly, BNN27 does not possess the hyperalgesic properties of NGF. BNN27 represents a lead molecule for the development of neuroprotective TrkA receptor agonists, with potential therapeutic applications in neurodegenerative diseases and in brain trauma.
BackgroundThe search for novel chemical entities targeting essential and parasite-specific pathways is considered a priority for neglected diseases such as trypanosomiasis and leishmaniasis. The thiol-dependent redox metabolism of trypanosomatids relies on bis-glutathionylspermidine [trypanothione, T(SH)2], a low molecular mass cosubstrate absent in the host. In pathogenic trypanosomatids, a single enzyme, trypanothione synthetase (TryS), catalyzes trypanothione biosynthesis, which is indispensable for parasite survival. Thus, TryS qualifies as an attractive drug target candidate.Methodology/Principal FindingA library composed of 144 compounds from 7 different families and several singletons was screened against TryS from three major pathogen species (Trypanosoma brucei, Trypanosoma cruzi and Leishmania infantum). The screening conditions were adjusted to the TryS´ kinetic parameters and intracellular concentration of substrates corresponding to each trypanosomatid species, and/or to avoid assay interference. The screening assay yielded suitable Z’ and signal to noise values (≥0.85 and ~3.5, respectively), and high intra-assay reproducibility. Several novel chemical scaffolds were identified as low μM and selective tri-tryp TryS inhibitors. Compounds displaying multi-TryS inhibition (N,N'-bis(3,4-substituted-benzyl) diamine derivatives) and an N5-substituted paullone (MOL2008) halted the proliferation of infective Trypanosoma brucei (EC50 in the nM range) and Leishmania infantum promastigotes (EC50 = 12 μM), respectively. A bis-benzyl diamine derivative and MOL2008 depleted intracellular trypanothione in treated parasites, which confirmed the on-target activity of these compounds.Conclusions/SignificanceNovel molecular scaffolds with on-target mode of action were identified as hit candidates for TryS inhibition. Due to the remarkable species-specificity exhibited by tri-tryp TryS towards the compounds, future optimization and screening campaigns should aim at designing and detecting, respectively, more potent and broad-range TryS inhibitors.
A series of N-substituted-quinolinone-3-aminoamides and their hybrids containing the alpha-lipoic acid functionality were designed and synthesized as potential bifunctional agents combining antioxidant and anti-inflammatory activity. The new compounds were evaluated for their antioxidant activity and for their ability to inhibit in vitro lipoxygenase as well as for their anti-inflammatory activity in vivo. In general, the derivatives were found to be potent antioxidant or anti-inflammatory agents. The results are discussed in terms of structure-activity relationships and an attempt is made to define the structural features required for activity.
Promising antibiofilm activity was displayed by miltefosine and other alkylphosphocholine compounds, which could be considered a putative option for future treatment of candidaemia associated with biofilm formation, although further evaluation in in vivo systems is required.
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