Comprehensive genetic analysis reveals the mutational landscape of ABCA4-associated retinal dystrophy in a Chinese cohort.

Purpose: To depict the variant profiles of the ABCA4 gene in a large Chinese cohort of patients with ABCA4-associated retinal dystrophy (ABCA4-RD).

Methods: We recruited 290 unrelated Chinese patients with ABCA4-RD and did ABCA4 mutational screening by a combination of Sanger sequencing, targeted exome sequencing, entire ABCA4 locus sequencing, and whole genome sequencing (WGS). The pathogenicity of variants was assessed using in silico tools or in vitro splicing assays following the American College of Medical Genetics and Genomics guidelines.

Down-expression of TaPIN1s Increases the Tiller Number and Grain Yield in Wheat.

Background: Tiller number is a factor determining panicle number and grain yield in wheat (Triticum aestivum). Auxin plays an important role in the regulation of branch production. PIN-FORMED 1 (PIN1), an auxin efflux carrier, plays a role in the regulation of tiller number in rice (Oryza sativa); however, little is known on the roles of PIN1 in wheat.

[Genetic diversity analysis of Andrographis paniculata in China based on SRAP and SNP].

In order to reveal genetic diversity of domestic Andrographis paniculata and its impact on quality, genetic backgrounds of 103 samples from 7 provinces in China were analyzed using SRAP marker and SNP marker. Genetic structures of the A. paniculata populations were estimated with Powermarker V 3.

Novel HIV-1 non-nucleoside reverse transcriptase inhibitors: a patent review (2011-2014).

Introduction: There is a continuous need for next-generation non-nucleoside RT inhibitors (NNRTIs) with different resistance profiles, improved safety, excellent tolerability, and favorable physicochemical properties.

Areas Covered: In this review we intend to narrate a general and cutting-edge overview of current state of NNRTI patents during the 2011-2014 (June) period and future perspectives. Particular focus is placed on the highlighting of some emerging medicinal chemistry principles and insights in the discovery and development of NNRTIs.

Recent advances in the structure-based rational design of TNKSIs.

Human tankyrases 1 and 2 (TNKS1/2) are attractive pharmacological biotargets, especially for the treatment of specific types of cancer. This article provides a fairly comprehensive overview of the structural biology of the TNKS-inhibitor complex and the current medicinal chemistry strategies being used in the structure-based rational design of tankyrase-specific inhibitors.

Conformational restriction: an effective tactic in 'follow-on'-based drug discovery.

The conformational restriction (rigidification) of a flexible ligand has often been a commonly used strategy in drug design, as it can minimize the entropic loss associated with the ligand adopting a preferred conformation for binding, which leads to enhanced potency for a given physiological target, improved selectivity for isoforms and reduced the possibility of drug metabolism. Therefore, the application of conformational restriction strategy is a core aspect of drug discovery and development that is widely practiced by medicinal chemists either deliberately or subliminally. The present review will highlight current representative examples and a brief overview on the rational design of conformationally restricted agents as well as discuss its advantages over the flexible counterparts.

Discovery and characterization of novel imidazopyridine derivative CHEQ-2 as a potent CDC25 inhibitor and promising anticancer drug candidate.

Cell division cycle (CDC) 25 proteins are key phosphatases regulating cell cycle transition and proliferation via the interactions with CDK/Cyclin complexes. Overexpression of CDC25 proteins is frequently observed in cancer and is related to aggressiveness, high-grade tumors and poor prognosis. Thus, inhibiting CDC25 activity in cancer treatment appears a good therapeutic strategy.

"Old Dogs with New Tricks": exploiting alternative mechanisms of action and new drug design strategies for clinically validated HIV targets.

HIV-1 reverse transcriptase, protease and integrase have been recognized as clinically validated but still underexploited targets for antiretroviral treatment. Although a large number of inhibitors have been used in clinical trials, the rapid emergence of multiple drug-resistant strains requires the identification of not only novel classes of antiretroviral drugs that act via the unprecedented mechanism of action but also innovative drug discovery strategies towards these three important targets. This review summarizes and discusses current endeavours towards the discovery and development of novel inhibitors with alternative mechanisms of action, and also provides examples illustrating new methodologies in medicinal chemistry that contribute to the identification of novel antiretroviral agents.

"Old friends in new guise": exploiting privileged structures for scaffold re-evolution/refining.

The attempts to increase novel drug productivity through creative discovery technologies have fallen short of producing the satisfactory results. For these reasons, evolved from the concept of drug repositioning, "privileged structure"-guided scaffold re-evolution/refining is a primary strategy to identify structurally novel chemotypes by modifying the central core structure and the side-chain of the existing active compounds, or to exploit undescribed bioactivites by making full use of readily derivatized motifs with well-established synthetic protocols. Herein, we review the basic tricks of exploiting privileged structures for scaffold re-evolution/refining.

Recent advances in the discovery and development of novel HIV-1 NNRTI platforms (Part II): 2009-2013 update.

The long-term usage of HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) eventually leads to rapid emergence of drug-resistant viruses and severe side effect. Therefore, it is imperative to seek the additional NNRTIs with potent and broad spectrum anti-mutant activities, and excellent pharmacokinetic profiles. The discovery of etravirine, rilpivirine and other successful examples has influenced the NNRTIs design strategy profoundly.

Heterocycle-thioacetic acid motif: a privileged molecular scaffold with potent, broad-ranging pharmacological activities.

Privileged structures can bind to multiple targets with high affinity, thus aiding the discovery of novel bioactive agents. Heterocycle- thioacetic acid derivatives, a group of molecules containing a heterocycle core linked with a thioacetic acid-derived fragment, represent an important type of "privileged scaffold" possessing a wide spectrum of biological properties. Numerous encouraging investigations demonstrated that this privileged structure should be extensively exploited for the therapeutic benefits.

Privileged scaffolds or promiscuous binders: a glance of pyrrolo[2,1-f][1,2,4]triazines and related bridgehead nitrogen heterocycles in medicinal chemistry.

Pyrrolo[2,1-f][1,2,4]triazine template, a unique bridgehead nitrogen heterocycle, certainly deserves the title of "privileged scaffold" in the drug discovery field because of the versatility and potential to yield derivatives with a wide range of biological activities, such as anti-anaplastic lymphoma kinase (ALK), Janus kinase 2 (JAK2), VEGFR-2, EGFR and/or HER2, Met kinase, p38α mitogen-activated protein (MAP) kinase and insulin-like growth factor receptor (IGF-1R) kinase activities, etc. These different biological properties of pyrrolo[2,1-f][1,2,4]triazine derivatives have motivated new studies in searching for novel derivatives with improved activity and also other applications in pharmaceutical field. However, no systematic review is available in the literature on the pyrrolo[2,1- f][1,2,4]triazine derivatives concerning the design of potent drug-like compounds.

Multivalent agents: a novel concept and preliminary practice in Anti-HIV drug discovery.

The term multivalency (polyvalency) in the biological science is defined as the simultaneous binding of multiple ligands to one receptor (or multiple receptors to one ligand). The possibility of gaining potency and selectivity was significantly increased through the use of multivalent ligand as a homo- or hetero-dimer, thus multivalent ligands provided a more attractive strategy to design novel anti-HIV agents with therapeutic applications. Moreover, similar to phenomenon of multivalency, an alternative strategy is called the "mixed sites inhibitor", viz.

Ligustrazine derivate DLJ14 reduces multidrug resistance of K562/A02 cells by modulating GSTπ activity.

Multidrug resistance (MDR) of tumor cells is a major obstacle in chemotherapeutic cancer treatment. Over-expression of glutathione S-transferase π (GSTπ) is one of the mechanisms contributing to MDR. In this study, we investigated the reversal of MDR by DLJ14, a ligustrazine derivate, in adriamycin (Adr) resistant human myelogenous leukemia (K562/A02) cells by modulating the expression of GSTπ and the activity of GST-related enzymes.

Mmp-9, a potential target for cerebral ischemic treatment.

Matrix metalloproteinase-9 (MMP-9) which is a member of matrix metalloproteinases family that normally remodel the extracellular matrix, has been shown to play an important role in both animal models of cerebral ischemia and human stroke. The expression of MMP-9 is elevated after cerebral ischemia which is involved in accelerating matrix degradation, disrupting the blood-brain barrier, increasing the infarct size and relating to hemorrhagic transformation. Recently, many drugs, such as tetracycline derivatives, cyclooxygenase inhibitors, ACEI inhibitors and AT1 receptor blockers, etc.

Regulation and role of organic anion-transporting polypeptides (OATPs) in drug delivery at the choroid plexus.

The organic anion-transporting polypeptides (rodents: Oatps; human: OATPs) belong to the growing family of organic anion/prostaglandin transporters and are important components of the active efflux transport system at the choroid plexus epithelial cells. OATPs facilitate the elimination of xenobiotics and endogenous waste from the cerebrospinal fluid and prevent waste accumulation in the central nervous system (CNS). This review summarizes the structures, regulations and roles of Oatps/OATPs at the choroid plexus in drug delivery to the CNS.

Connexin 43, a new therapeutic target for cardiovascular diseases.

Junctional channels (JC) play essential roles in the normal function of the cardiovascular system, mediating the spread of the electrical impulse that triggers synchronized contraction of the cardiac chambers and contributing to the coordination of activities between cells of the arterial wall. In mammalian hearts, cells most prominently express JC built of Connexin40 (Cx40), Cx43 and Cx45, of which Cx43 is the predominant intercellular gap junction protein. Changes in cardiovascular Cx gene expression during development or in response to (patho)physiological signals are expected to be a crucial factor in normal cardiac development and functions, and several cardiac diseases, such as atrial fibrillation, hypertrophy, heart failure, atherosclerosis, etc.

Ligustrazine derivatives. Part 3: Design, synthesis and evaluation of novel acylpiperazinyl derivatives as potential cerebrocardiac vascular agents.

A series of novel acylpiperazinyl Ligustrazine derivatives was designed, synthesized, and their protective effects on damaged ECV-304 cells and antiplatelet aggregation activities were evaluated. The results showed that compound E33 displayed most potential protective effects on the ECV-304 cells damaged by hydrogen peroxide, and compound E1 was found to be the most active antiplatelet aggregation agent. Structure-activity relationships were briefly discussed.