In Brief

Gene therapy

Molecular ablation of ventricular tachycardia after myocardial infarction. Sasano, T. et al. Nature Med. 12, 1256–1258 (2006)

Individuals who suffer a myocardial infarction are often subsequently at risk of ventricular tachycardia (VT). Recent problems with defibrillator implantation, the only therapeutic option for patients at risk from this complication, has led to the search for alternative treatment strategies. In a proof-of-principle study, Sasano et al. demonstrate that transferring a gene encoding a dominant-negative version of the KCNH2 potassium channel to the border of the infarct scar eliminated all ventricular arrhythmias in a porcine model of inducible VT.

Diabetes

Production of pancreatic hormone-expressing endocrine cells from human embryonic cells. D'Amour, K. A. et al. Nature Biotechnol. 24, 1392–1401 (2006)

Attempts to differentiate human embryonic stem cells into insulin-producing cells for potential therapy of diabetes have been hindered by inefficiency of differentiation and the low insulin content of the resulting cells. Now, in a crucial step forward, D'Amour et al. describe a differentiation process in which cells are directed through different stages of development that mimic in vivo pancreatic organogenesis. The result is differentiated endocrine cells that are capable of synthesizing the pancreatic hormones insulin, glucagon, somatostatin, pancreatic polypeptide and ghrelin, and have an insulin content similar to that of adult pancreatic islets.

Antibacterial drugs

A linguistic model for the rational design of antimicrobial peptides. Loose, C. et al. Nature 443, 867–869 (2006)

The antimicrobial peptides (AmPs) made by many organisms to ward off bacterial infection are thought to be less susceptible to the development of resistance and so represent an attractive new class of antimicrobial drugs. This paper describes the rational design of a set of peptides using a 'linguistic model' of naturally occurring AmPs, which involves viewing the amino-acid sequences of these peptides as a language to which a set of grammars is assigned. This grammar set is then used to create novel, unnatural AmP sequences. The authors identified several peptides with bacteriostatic activity against various bacterial species, including Staphylococcus aureus and Bacillus anthracis.

Cancer

Targeting β₂-microglobulin for induction of tumor apoptosis in human hematological malignancies. Yang, J. et al. Cancer Cell 295–307 (2006)

Levels of β₂-microglobulin (β₂M), part of the major histocompatibility complex (MHC) class I molecule, are elevated in several haematological malignancies. While studying the importance of this using an anti-β₂M monoclonal antibody (mAb), Yang et al. noticed that the mAbs had a strong apoptotic effect on the cancer cells. Here they describe how recruitment of MHC class I molecules to lipid rafts initiates a series of events that culminates in caspase-9-dependent apoptosis. The anti-β₂M mAbs had potent anticancer activity in several haematological tumour cell lines and against established tumours in animal models, and also good toxicity profiles.