The findings suggest that NOX-derived ROS results in increased mito-ROS. Whereas short-term increase in mito-ROS was counteracted by MnSOD, long-term increase in ROS resulted in nitrotyrosine-mediated inactivation of MnSOD, leading to unchecked increase in mito-ROS and loss of Δψm followed by inhibition of endothelial function and proliferation.

SHORT ABSTRACT We provide a reliable method for left anterior descending artery (LAD) ligation in a mouse model. This method is comparatively less invasive than other methods, involving endotracheal intubation, a left-sided thoracotomy approach, and thoracentesis. This method can be used as a model for both acute and chronic myocardial infarction (MI). LONG ABSTRACT Ischemic heart disease (IHD) or acute coronary syndrome (ACS) is one of the leading causes of death in the United States. IHD is characterized by reduced blood supply to the heart resulting in loss of oxygen to, and resultant necrosis of, the heart muscle. The MI model has gained popularity for its use as short-term ischemia-reperfusion model and long-term permanent ligation model. Below we describe a reliable method for permanent ligation of the LAD. With mouse genetic engineering technology becoming more advanced, and with an increasing availability of quality murine surgical instruments, the mouse has become a popular model for MI surgeries. Our surgical model incorporates the use of easily reversible anesthetic for rapid recovery of the mouse, minimally invasive endotracheal intubation without involving tracheotomy, and thoracentesis through the original thoracotomy site without creating an additional incision in the chest as is done in some other methods, to effectively remove excess blood and air from the chest cavity. This method is comparatively less invasive than other methods, which dramatically reduces surgical/post-surgical complications and mortality, and improves reproducibility.

Ci-MRF is the sole myogenic regulatory factor (MRF) of the ascidian Ciona intestinalis, an invertebrate chordate. In order to investigate its properties we developed a simple in vivo assay based on misexpressing Ci-MRF in the notochord of Ciona embryos. We used this assay to examine the roles of three structural motifs that are conserved among MRFs: an alanine-threonine (Ala-Thr) dipeptide of the basic domain that is known in vertebrates as the myogenic code, a cysteine/histidine-rich (C/H) domain found just N-terminal to the basic domain, and a carboxy-terminal amphipathic α-helix referred to as Helix III. We show that the Ala-Thr dipeptide is necessary for normal Ci-MRF function, and that while eliminating the C/H domain or Helix III individually has no demonstrable effect on Ci-MRF, simultaneous loss of both motifs significantly reduces its activity. Our studies also indicate that direct interaction between CiMRF and an essential E-box of Ciona Troponin I is required for the expression of this muscle-specific gene and that multiple classes of MRF-regulated genes exist in Ciona. These findings are consistent with substantial conservation of MRF-directed myogenesis in chordates and demonstrate for the first time that the Ala/Thr dipeptide of the basic domain of an invertebrate MRF behaves as a myogenic code.