How technical progress reshaped behavioral neuroendocrinology during the last 50 years and some methodological remarks.

The first issue of Hormones and Behavior was published 50 years ago in 1969, a time when most of the techniques we currently use in Behavioral Endocrinology were not available. Researchers have during the last 5 decades developed techniques that allow measuring hormones in small volumes of biological samples, identify the sites where steroids act in the brain to activate sexual behavior, characterize and quantify gene expression correlated with behavior expression, modify this expression in a specific manner, and manipulate the activity of selected neuronal populations by chemogenetic and optogenetic techniques. This technical progress has considerably transformed the field and has been very beneficial for our understanding of the endocrine controls of behavior in general, but it did also come with some caveats. The facilitation of scientific investigations came with some relaxation of methodological exigency. Some critical controls are no longer performed on a regular basis and complex techniques supplied as ready to use kits are implemented without precise knowledge of their limitations. We present here a selective review of the most important of these new techniques, their potential problems and how they changed our view of the hormonal control of behavior. Fortunately, the scientific endeavor is a self-correcting process. The problems have been identified and corrections have been proposed. The next decades will obviously be filled with exciting discoveries in behavioral neuroendocrinology.

[Development of Protein Knockdown Technology as Emerging Drug Discovery Strategy].

　Protein knockdown technologies based on small molecules are attracting considerable attention in the pharmaceutical industry as a strategy for novel drug discovery. We and others have developed such compounds, designated as Specific and Nongenetic Inhibitor of Apoptosis Protein (IAP)-dependent Protein Erasers (SNIPERs), proteolysis-targeting chimeras (PROTACs), and Degronimids, which induce selective degradation of target proteins. These compounds contain two different ligands, specific for an ubiquitin E3 ligase and for a target protein, respectively, connected by a linker. SNIPERs, PROTACs, and Degronimids are designed to cross-link E3 ligase and the target protein to induce polyubiquitylation and proteasomal degradation of the target protein within cells. To recruit the von Hippel-Lindau (VHL) E3 ligase complex and the cereblon (CRBN) E3 ligase complex, a VHL inhibitor and a thalidomide derivative have been integrated into PROTAC and Degronimid constructs, respectively. Similarly, an IAP antagonist has been incorporated into SNIPERs to recruit cellular inhibitor of apoptosis protein 1 (cIAP1) or X-linked inhibitor of apoptosis protein (XIAP) E3 ligase. To date, a range of such compounds have been developed, allowing selective degradation of a variety of proteins, including estrogen receptor α (ERα), oncogenic kinase BCR-ABL, and epigenetic regulator bromodomain-containing protein 4 (BRD4). Some compounds have also demonstrated ability to degrade target proteins in vivo, suggesting that this technology is feasible for use in novel drug development.

Tapping into Salmonella typhimurium LT2 genome in a quest to explore its therapeutic arsenal: A metabolic network modeling approach.

S. typhimurium, the classical broad-host-range serovar is a widely distributed cause of food-borne illness. Escalating antibiotic resistance and potential of conjugal transmission to other pathogens attributable to its broad spectrum host specificities have aided S. typhimurium to emerge as a global health threat. To keep pace with ever evolving bacterial defenses, there is dire need to restock the antibiotic pipeline. Genome scale metabolic reconstructions present immense possibilities to decipher physiological properties of an organism using constraint-based methods The systems-level approaches of genome scale metabolic networks interrogation open up new avenues of drug target identification against deadly infectious diseases. We performed flux balance analysis and minimization of metabolic adjustment studies of genome scale reconstruction model of S. typhimurium targeted at identifying large number of metabolites with a potential to be utilized as therapeutic drug targets. These constraint based approaches initially predict a set of genes indispensable to bacterial survival by performing gene knockout studies which are then prioritized through a multistep process. Metabolites involved in l-rhamnose biosynthesis, peptidoglycan biosynthesis, fatty acid biosynthesis, and folate biosynthesis pathways were prioritized as candidate drug targets. This study provides a general therapeutic approach which can be effectively applied to other pathogens as well.

Regulation of the fetal hemoglobin silencing factor BCL11A.

The clinical severity of sickle cell disease and ß-thalassemia, the major disorders of ß-globin, can be ameliorated by increased production of fetal hemoglobin (HbF). Here, we provide a brief overview of the fetal-to-adult hemoglobin switch that occurs in humans shortly after birth and review our current understanding of one of the most potent known regulators of this switching process, the multiple zinc finger-containing transcription factor BCL11A. Originally identified in genome-wide association studies, multiple orthogonal lines of evidence have validated BCL11A as a key regulator of hemoglobin switching and as a promising therapeutic target for HbF induction. We discuss recent studies that have highlighted its importance in silencing the HbF-encoding genes and discuss opportunities that exist to further understand the regulation of BCL11A and its mechanism of action, which could provide new insight into opportunities to induce HbF for therapeutic purposes.

Reverse Genetics in Zebrafish: Mutants, Morphants, and Moving Forward.

Gene editing in zebrafish has begun to reveal discordance between mutant phenotypes and those associated with knockdown via morpholino oligonucleotides (MOs). These studies suggest that MOs should not be used as a standalone tool and underscore the need for guidelines that require defined mutants to assess gene function in zebrafish.

RNAi in the mouse: rapid and affordable gene function studies in a vertebrate system.

The addition of RNA interference (RNAi) to the mammalian genomic toolbox has significantly expanded our ability to use higher-order models in studies of development and disease. The mouse, in particular, has benefited most from RNAi technology. Unique combinations of RNAi vectors and delivery methods now offer a broad platform for gene silencing in transgenic mice, enabling the design of new physiologically relevant models. The era of RNAi mice has accelerated the pace of genetic study and made high-throughput screens not only feasible but also affordable.

New therapeutic opportunities in epilepsy: a genetic perspective.

Epilepsy is a common and serious neurological disorder. Despite recent advances in drug therapy, treatment for epilepsy is still largely empirical and rational prescribing based on the mechanism of action in an individual patient is generally not possible. Genetic studies have identified an increasing collection of disease-causing genes providing a fundamental molecular foundation on which to build this understanding, at least for some forms of epilepsy. The impact of these genetic discoveries is likely to be wide reaching-from the discovery and validation of new drug targets to the potential to enable rational prescribing based on genetic makeup and even further through animal experimentation to tease out molecular and cellular mechanisms that lead to hyperexcitable neuronal networks causing epilepsy. Here we discuss how we can use knowledge of genetic mechanisms to improve treatment strategies now and into the future.

Knocking down gene expression with dendritic vectors.

The aim of this review is to provide the reader with an overview on the potential of dendritic polymers in the antisense delivery technology. Special emphasis has been placed on the different types of dendritic structures that have been reported and the modifications performed to increase their efficacy and safety. Therefore the advances made in their chemistry and how it has been adapted to meet the specific requirements of the antisense delivery technology are reviewed and discussed.