How does the quality of phospholipidosis data influence the predictivity of structural alerts?

The ability of drugs to induce phospholipidosis (PLD) is linked directly to their molecular substructures: hydrophobic, cyclic moieties with hydrophilic, peripheral amine groups. These structural properties can be captured and coded into SMILES arbitrary target specification (SMARTS) patterns. Such structural alerts, which are capable of identifying potential PLD inducers, should ideally be developed on a relatively large but reliable data set. We had previously developed a model based on SMARTS patterns consisting of 32 structural fragments using information from 450 chemicals. In the present study, additional PLD structural alerts have been developed based on a newer and larger data set combining two data sets published recently by the United States Food and Drug Administration (US FDA). To assess the predictive performance of the updated SMARTS model, two publicly available data sets were considered. These data sets were constructed using different criteria and hence represent different standards for overall quality. In the first data set high quality was assured as all negative chemicals were confirmed by the gold standard method for the detection of PLD-transmission electron microscopy (EM). The second data set was constructed from seven previously published data sets and then curated by removing compounds where conflicting results were found for PLD activity. Evaluation of the updated SMARTS model showed a strong, positive correlation between predictive performance of the alerts and the quality of the data set used for the assessment. The results of this study confirm the importance of using high quality data for modeling and evaluation, especially in the case of PLD, where species, tissue, and dose dependence of results are additional confounding factors.

Kisspeptin a potential therapeutic target in treatment of both metabolic and reproductive dysfunction.

Kisspeptins (KPs) are proteins that were first recognized to have antimetastatic action. Later, the critical role of this peptide in the regulation of reproduction was proved. In recent years, evidence has been accumulated supporting a role for KPs in regulating metabolic processes in a sexual dimorphic manner. It has been proposed that KPs regulate metabolism both indirectly via gonadal hormones and/or directly via the kisspeptin receptor in the brain, brown adipose tissue, and pancreas. The aim of the review is to provide both experimental and clinical evidence indicating that KPs are peptides linking metabolism and reproduction. We propose that KPs could be used as a potential target to treat both metabolic and reproductive abnormalities. Thus, we focus on the consequences of disruptions in KPs and their receptors in metabolic conditions such as diabetes, undernutrition, obesity, and reproductive disorders (hypogonadotropic hypogonadism and polycystic ovary syndrome). Data from both animal models and human subjects indicate that alterations in KPs in the case of metabolic imbalance lead also to disruptions in reproductive functions. Changes both in the hypothalamic and peripheral KP systems in animal models of the aforementioned disorders are discussed. Finally, an overview of current clinical studies involving KP in fertility and metabolism show fewer studies on metabolism (15%) and only one to date on both. Presented data indicate a dynamic and emerging field of KP studies as possible therapeutic targets in treatments of both reproductive and metabolic dysfunctions.