These findings indicate that room light exerts a profound suppressive effect on melatonin levels and shortens the body's internal representation of night duration. Hence, chronically exposing oneself to electrical lighting in the late evening disrupts melatonin signaling and could therefore potentially impact sleep, thermoregulation, blood pressure, and glucose homeostasis.

This article appears in The Journal of Clinical Endocrinology & Metabolism, published December 30, 2010, 10.1210/jc.2010-2098

Recombinant adeno-associated virus vectors (rAAV) are being explored as gene delivery vehicles for the treatment of various inherited and acquired disorders. rAAVs are attractive vectors for several reasons: wild-type AAVs are nonpathogenic, and rAAVs can trigger long-term transgene expression even in the absence of genome integration-at least in postmitotic tissues. Moreover, rAAVs have a low immunogenic profile, and the various AAV serotypes and variants display broad but distinct tropisms. One limitation of rAAVs is that their genome-packaging capacity is only *5 kb. For most applications this is not of major concern because the median human protein size is 375 amino acids. Excluding the ITRs, for a protein of typical length, this allows the incorporation of *3.5 kb of DNA for the promoter, polyadenylation sequence, and other regulatory elements into a single AAV vector. Nonetheless, for certain diseases the packaging limit of AAV does not allow the delivery of a full-length therapeutic protein by a single AAV vector. Hence, approaches to overcome this limitation have become an important area of research for AAV gene therapy. Among the most promising approaches to overcome the limitation imposed by the packaging capacity of AAV is the use of dual-vector approaches, whereby a transgene is split across two separate AAV vectors. Coinfection of a cell with these two rAAVs will then-through a variety of mechanismsresult in the transcription of an assembled mRNA that could not be encoded by a single AAV vector because of the DNA packaging limits of AAV. The main purpose of this review is to assess the current literature with respect to dual-AAV-vector design, to highlight the effectiveness of the different methodologies and to briefly discuss future areas of research to improve the efficiency of dual-AAV-vector transduction.

Field isolates of foot-and-mouth disease virus (FMDVF oot-and-mouth disease (FMD) is endemic in many regions of the world and is one of the most widespread, epizootic transboundary animal diseases, affecting many species of wildlife and livestock, such as cattle, sheep, goats, and pigs. The significant economic losses that result from FMD are due to the high morbidity of infected animals and stringent trade restrictions imposed on affected countries (1). Vaccination plays a major role in controlling FMD, either to lessen the effects of an outbreak in FMDfree countries or for control and eradication in regions where it is endemic. The etiological agent of FMD, foot-and-mouth disease virus (FMDV), exists as seven distinct serotypes (O, A, C, Asia-1, and the Southern African Territories [SAT] serotypes SAT-1, SAT-2, and SAT-3). Within each serotype, a large number of antigenic variants exist (2). Intraserotype diversity is driven by a high mutation rate during replication that is caused by an error-prone viral RNA-dependent RNA polymerase (3) and thus complicates efforts to control disease by vaccination due to incomplete protection between some antigenic variants (4). Hence, the most effective vaccines closely match the outbreak virus, which can necessitate the development of new vaccine strains. The current vaccines are inactivated virus preparations grown in large-scale cell culture. Therefore, the production of a new vaccine is critically dependent upon adaptation of viruses from the field for growth in cell culture, which can prove problematical for some viruses.Foot-and-mouth disease virus is the type species of the Aphthovirus genus of the Picornaviridae, a family of nonenveloped, single-stranded positive-sense RNA viruses. The viral capsid is formed by 60 copies each of four structural proteins (VP1 to VP4) arranged in icosahedral symmetry. The outer capsid surfaces are formed by VP1, which surrounds the five-fold symmetry axis, and VP2 and VP3, which alternate around the three-fold axis (5). VP4 is myristoylated and located inside the capsid and is thought to play an essential role in the final stage of assembly and in endosomal membrane penetration by the viral RNA (6, 7). In vivo, FMDV has a strong tropism for epithelial cells, which is in part due to the epithelial cell-restricted expression of integrin ␣v␤6, which is the principal receptor used by field viruses to initiate infection (8-12). Integrin binding is mediated by a highly conserved arginine-glycine-aspartic acid (RGD) motif located at the apex of a structurally disordered loop (the GH loop of VP1). The integrin specificity of FMDV has been the subject of several studies, and three other RGD-dependent integrins (␣v␤1, ␣v␤3, and ␣v␤8) have also been reported to be receptors for field strains of the virus (13-15); however, the role of these integrins in pathogenesis is unclear, and we have found that ␣v␤3 is a poor receptor for FMDV in vitro (16). Furthermore, despite recognizing their ligands via the RGD motif, two other RGD-dependent integrins ...

Purpose of Review Cardiac gene therapy with adeno-associated virus (AAV)-based vectors is emerging as an entirely new platform to treat, or even cure, so far intractable cardiac disorders. This review describes our current knowledge of cardiac AAV gene therapy with a particular focus on the biggest obstacle for the successful translation of cardiac AAV gene therapy into the clinic, namely the efficient delivery of the therapeutic gene to the myocardium. Recent Findings We summarize the significant recent progress that has been made in treating heart failure in preclinically relevant animal models with AAV gene therapy and the recent results of clinical trials with cardiac AAV gene therapy for the treatment of heart failure. We also discuss the benefits and shortcomings of the currently available delivery methods of AAV to the heart. Finally, we describe the current state of identifying novel AAV variants that have enhanced tropism for human cardiomyocytes and that show increased resistance to pre-existing neutralizing antibodies. Summary Here we describe the successes and challenges in cardiac AAV gene therapy, a treatment modality that has the potential to transform current treatment approaches for cardiac diseases.