دانلود رایگان مقاله خواص داروی میکرونوروتروفین جهت درمان اسکلروزیس جانبی آمیوتروفیک

Abstract

Microneurotrophins (MNT’s) are small molecule derivatives of dehydroepiandrosterone (DHEA) and do not have significant interactions with sex steroid receptors. MNT’s retain high-affinity binding to protein tyrosine kinase (Trk) receptors and can mimic many pleiotropic actions of neurotrophin (NT) proteins on neurons. MNT’s offer therapeutic potential for diseases such as amyotrophic lateral sclerosis (ALS) where motor neurons (MN) degenerate. MNT’s cross artificial membranes mimicking the blood–brain barrier, are not major substrates for ABC (ATP-binding cassette) transporters and are metabolized rapidly by mouse but more slowly by human hepatocytes. A lead MNT (BNN27) and its mono-oxidation metabolites enter mouse brain rapidly. RNA-sequencing measured gene expression profiles of human H9eSC-(embryonic stem cell)-derived or CTL (control) subject iPSC-(induced pluripotential stem cell)-derived MN’s exposed to NT proteins or MNT molecules. Expression ratios (relative to DMSO (dimethylsulfoxide) vehicle) were calculated, and the resulting top 500 gene lists were analyzed for Gene Ontology (GO) grouping using DAVID (Database for Annotation, Visualization and Integrated Discovery). The MNT’s BNN20, BNN23, and BNN27 showed overlap of GO terms with NGF (nerve growth factor) and BDNF (brain-derived neurotrophic factor) in the H9eSC-derived MN’s. In the iPSC-derived MN’s two (BNN20, BNN27) showed overlap of GO terms with NGF or BDNF. Each NT protein had GO terms that did not overlap with any MNT in the MN cell lines.

4. Discussion and conclusions

To date no cell or animal model of ALS accurately predicts effi- cacy of neuroprotective treatments for the most commonly occurring, sporadic form of the illness (sALS). Because of the survivalpromoting, pleiotropic actions of neurotrophins on neurons [24], and the demonstrated efficacy of neurotrophins or neurotrophin receptors in preventing motor neuron death following axotomy [25–27], we are pursuing the pre-clinical development of microneurotrophins for ALS. As part of this development effort, we characterized the in vitro permeability of the MNT’s to artificial membrane and their interactions with ABC transporters that can remove drugs by reversepumping across the BBB. We observed that MNT’s had excellent potential BBB permeability and were not major substrates for ABC drug transporters. We then examined the metabolism of a lead MNT, BNN27, by mouse and human liver cells. We observed rapid metabolism by mouse and slower metabolism by human liver cells. In both systems BNN27 metabolites could be detected and are likely ring single hydroxylation metabolites produced by the cytochrome P450 system. However, because we did not characterize any of the metabolites structurally, we can only speculate as to their chemical identity.