Development of an automated screen for Kv7.2 potassium channels and discovery of a new agonist chemotype.

To identify pore domain ligands on Kv7.2 potassium ion channels, we compared wild-type (WT) and W236L mutant Kv7.2 channels in a series of assays with previously validated and novel agonist chemotypes. Positive controls were retigabine, flupirtine, and RL-81; i.e. Kv7.2 channel activators that significantly shift voltage-dependent activation to more negative potentials (ΔV50) at 5 µM. We identified 6 new compounds that exhibited differential enhancing activity between WT and W236L mutant channels. Whole cell patch-clamp electrophysiology studies were conducted to identify Kv7.2. Kv7.2/3, Kv7.4, and Kv7.5 selectivity. Our results validate the SyncroPatch platform and establish new structure activity relationships (SAR). Specifically, in addition to selective Kv7.2, Kv7.2/3, Kv7.4. and Kv7.5 agonists, we identified a novel chemotype, ZK-21, a 4-aminotetrahydroquinoline that is distinct from any of the previously described Kv7 channel modifiers. Using flexible receptor docking, ZK-21 was predicted to be stabilized by W236 and bind perpendicular to retigabine, burying the benzyl carbamate group into a tunnel reaching the core of the pore domain.

Improved correction of F508del-CFTR biogenesis with a folding facilitator and an inhibitor of protein ubiquitination.

A growing number of diseases are linked to the misfolding of integral membrane proteins, and many of these proteins are targeted for ubiquitin-proteasome-dependent degradation. One such substrate is a mutant form of the Cystic Fibrosis Transmembrane Conductance Regulator (F508del-CFTR). Protein folding "correctors" that repair the F508del-CFTR folding defect have entered the clinic, but they are unlikely to protect the entire protein from degradation. To increase the pool of F508del-CFTR protein that is available for correction by existing treatments, we determined a structure-activity relationship to improve the efficacy and reduce the toxicity of an inhibitor of the E1 ubiquitin activating enzyme that facilitates F508del-CFTR maturation. A resulting lead compound lacked measurable toxicity and improved the ability of an FDA-approved corrector to augment F508del-CFTR folding, transport the protein to the plasma membrane, and maintain its activity. These data support a proof-of-concept that modest inhibition of substrate ubiquitination improves the activity of small molecule correctors to treat CF and potentially other protein conformational disorders.

Balamuthia amebic meningoencephalitis and mycotic aneurysms in an infant.

Balamuthia amebic encephalitis is rarely reported in infants. To the best of our knowledge, amebic encephalitis complicated by a mycotic aneurysm was only described once. We report on an 8-month-child with laboratory-confirmed Balamuthia mandrillaris meningoencephalitis, complicated by a mycotic aneurysm of the middle cerebral artery.

The meaning of evidence: can practitioners be researchers?

Our research group at Southampton contains a combination of non-clinical researchers as well as CAM and conventional clinicians who have become researchers. The transition from practitioner to practitioner-researcher has led us to question, challenge and re-consider the paradigmatic differences in our practices compared to conventional medicine and how we might understand and interpret evidence derived from both quantitative and qualitative research. We very much value the randomised controlled trial (RCT) but have all come to understand its limitations and constraints when trying to encapsulate a complete, rigorous, and honest understanding of our complex interventions and how they are delivered in practice. Equally, our expertise in qualitative research leads us to understand the patient's perspective and to value a more individual agenda. We believe that we share these tensions with clinicians working in primary care. We appreciate that we need to understand contextual effects so we can better utilise and research them appropriately, rather than dismiss them as mere placebo. These issues represent both personal and transcendent conflicts that we have expressed as a series of vignettes each written by a practitioner/researcher working in that filed. Our principle aim in writing this essay is to offer our practical experience and insight as issues for thoughtful debate for those clinicians and academics involved in clinical research in controversial areas such as CAM.

Mutations in SOX2 cause anophthalmia-esophageal-genital (AEG) syndrome.

We report heterozygous, loss-of-function SOX2 mutations in three unrelated individuals with Anophthalmia-Esophageal-Genital (AEG) syndrome. One previously reported case [Rogers, R.C. (1988) Unknown cases. Proceedings of the Greenwood Genetic Center. 7, 57.] has a 2.7 Mb deletion encompassing SOX2 and associated with a cryptic translocation t(3;7)(q28;p21.3). The deletion and translocation breakpoints on chromosome 3q are >8.6 Mb apart and both chromosome rearrangements have occurred de novo. Another published case [Petrackova et al. (2004) Association of oesophageal atresia, anophthalmia and renal duplex. Eur. J. Pediatr., 163, 333-334.] has a de novo nonsense mutation, Q55X. A previously unreported case with severe bilateral microphthalmia and oesophageal atresia has a de novo missense mutation, R74P, that alters a highly evolutionarily conserved residue within the high mobility group domain, which is critical for DNA-binding of SOX2. In a yeast one-hybrid assay, this mutation abolishes Sox2-induced activation of the chick delta-crystallin DC5 enhancer. Four other reported AEG syndrome cases were extensively screened and do not have detectable SOX2 mutations. Two of these cases have unilateral eye malformations. SOX2 mutations are known to cause severe bilateral eye malformations but this is the first report implicating loss of function mutations in this transcription factor in oesophageal malformations. SOX2 is expressed in the developing foregut in mouse and zebrafish embryos and an apparently normal pattern of expression is maintained in Shh-/- mouse embryos, suggesting either that Sox2 acts upstream of Shh or functions in a different pathway. Three-dimensional reconstructions of the major morphological events in the developing foregut and eye from Carnegie Stages 12 and 13 human embryos are presented and compared with the data from model organisms. SOX2, with NMYC and CHD7, is now the third transcriptional regulator known to be critical for normal oesophageal development in humans.

Molecular basis of the spectral expression of CIAS1 mutations associated with phagocytic cell-mediated autoinflammatory disorders CINCA/NOMID, MWS, and FCU.

NALP proteins are recently identified members of the CATERPILLER (CARD, transcription enhancer, R(purine)-binding, pyrin, lots of LRR) family of proteins, thought to function in apoptotic and inflammatory signaling pathways. Mutations in the CIAS1 gene, which encodes a member of the NALP (NACHT-, LRR-, and PYD-containing proteins) family, the cryopyrin/NALP3/PYPAF1 protein, expressed primarily in phagocytic cells, were recently found to be associated with a spectrum of autoinflammatory disorders. These include chronic infantile neurologic cutaneous and articular (CINCA) syndrome (also known as neonatal-onset multisystem inflammatory disease [NOMID]), Muckle-Wells syndrome (MWS), and familial cold urticaria (FCU). We describe herein 7 new mutations in 13 unrelated patients with CINCA syndrome and identify mutational hotspots in CIAS1 on the basis of all mutations described to date. We also provide evidence of genotype/phenotype correlations. A 3-dimensional model of the nucleotide-binding domain (NBD) of cryopyrin suggested that this molecule is structurally and functionally similar to members of the AAA+ protein family of ATPases. According to this model, most of the mutations known to affect residues of the NBD are clustered on one side of this domain in a region predicted to participate in intermolecular contacts, suggesting that this model is likely to be biologically relevant and that defects in nucleotide binding, nucleotide hydrolysis, or protein oligomerization may lead to the functional dysregulation of cryopyrin in the MWS, FCU, and CINCA/NOMID disorders.