Cardiac Transplantation in Danon Disease.

BACKGROUND: Danon disease (DD) is a rare X-linked dominant cardioskeletal myopathy caused by mutations in the lysosome-associated membrane protein-2 (LAMP-2) gene that is usually lethal without cardiac transplantation. The purpose of this study was to characterize post-transplant outcomes in a large cohort of patients with DD who underwent cardiac transplantation. METHODS: The clinical phenotype and outcome data of patients with DD who underwent cardiac transplantation (n = 38; 19 males and 19 females) were obtained from 8 centers. Study outcomes included graft survival, defined as death or retransplantation, and episodes of acute cellular and antibody-mediated rejection and cardiac allograft vasculopathy at 1 year. RESULTS: Median follow-up time after transplantation for the entire cohort was 4.4 years (IQR: 1.5-12.8 years). The median age at transplant for the cohort was 20.2 years (15.8-27.9 years), with no difference in age between sexes. Median pretransplant left-ventricular ejection fraction for the entire cohort was 30% (range 11%-84%). Males had higher pretransplant aspartate aminotransferase, alanine aminotransferase and creatine phosphokinase levels than females (P < 0.001). There were 2 deaths in the entire cohort and 2 retransplants. There was no difference in actuarial graft survival between males and females (P = 0.8965); the estimated graft survival was 87.1% (95%CI: 63.6%-95.9%) at 5 years. One episode (2.7%) of antibody-mediated rejection, grade 2, and 7 episodes (19%) of acute cellular rejection, grade 2 or 3, were reported in patients who survived to discharge (6 females and 1 male; P = 0.172). CONCLUSIONS: Heart transplantation outcomes are acceptable in DD with high probabilities of 5-year graft survival for males and females suggesting that cardiac transplantation is an effective treatment option for DD patients.

Glutathione activates virulence gene expression of an intracellular pathogen.

Intracellular pathogens are responsible for much of the world-wide morbidity and mortality due to infectious diseases. To colonize their hosts successfully, pathogens must sense their environment and regulate virulence gene expression appropriately. Accordingly, on entry into mammalian cells, the facultative intracellular bacterial pathogen Listeria monocytogenes remodels its transcriptional program by activating the master virulence regulator PrfA. Here we show that bacterial and host-derived glutathione are required to activate PrfA. In this study a genetic selection led to the identification of a bacterial mutant in glutathione synthase that exhibited reduced virulence gene expression and was attenuated 150-fold in mice. Genome sequencing of suppressor mutants that arose spontaneously in vivo revealed a single nucleotide change in prfA that locks the protein in the active conformation (PrfA*) and completely bypassed the requirement for glutathione during infection. Biochemical and genetic studies support a model in which glutathione-dependent PrfA activation is mediated by allosteric binding of glutathione to PrfA. Whereas glutathione and other low-molecular-weight thiols have important roles in redox homeostasis in all forms of life, here we demonstrate that glutathione represents a critical signalling molecule that activates the virulence of an intracellular pathogen.