Cardiac-directed expression of a catalytically inactive adenylyl cyclase 6 protects the heart from sustained β-adrenergic stimulation.

ObjectivesIncreased expression of adenylyl cyclase type 6 (AC6) has beneficial effects on the heart through cyclic adenosine monophosphate (cAMP)-dependent and cAMP-independent pathways. We previously generated a catalytically inactive mutant of AC6 (AC6mut) that has an attenuated response to β-adrenergic receptor stimulation, and, consequently, exhibits reduced myocardial cAMP generation. In the current study we test the hypothesis that cardiac-directed expression of AC6mut would protect the heart from sustained β-adrenergic receptor stimulation, a condition frequently encountered in patients with heart failure.Methods and resultsAC6mut mice and transgene negative siblings received osmotic mini-pumps to provide continuous isoproterenol infusion for seven days. Isoproterenol infusion caused deleterious effects that were attenuated by cardiac-directed AC6mut expression. Both groups showed reduced left ventricular (LV) ejection fraction, but the reduction was less in AC6mut mice (p = 0.047). In addition, AC6mut mice showed superior left ventricular function, manifested by higher values for LV peak +dP/dt (p = 0.03), LV peak -dP/dt (p = 0.008), end-systolic pressure-volume relationship (p = 0.003) and cardiac output (p<0.03). LV samples of AC6mut mice had more sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) protein (p<0.01), which likely contributed to better LV function. AC6mut mice had lower rates of cardiac myocyte apoptosis (p = 0.016), reduced caspase 3/7 activity (p = 0.012) and increased B-cell lymphoma 2 (Bcl2) expression (p = 0.0001).ConclusionMice with cardiac-directed AC6mut expression weathered the deleterious effects of continuous isoproterenol infusion better than control mice, indicating cardiac protection

Effects of Urocortin 2 Gene Transfer on Glucose Disposal in Insulin-Resistant db/db Mice on Metformin.

The study was designed to determine whether urocortin 2 (Ucn2) gene transfer is as safe and effective as metformin in insulin-resistant mice. Four groups of insulin-resistant db/db mice and a nondiabetic group were studied: (1) metformin; (2) Ucn2 gene transfer; (3) metformin + Ucn2 gene transfer; (4) saline; and (5) nondiabetic mice. After completion of the 15-week protocol, glucose disposal was quantified, safety assessed, and gene expression documented. Ucn2 gene transfer was superior to metformin, providing reductions in fasting glucose and glycated hemoglobin and enhanced glucose tolerance. The combination of metformin + Ucn2 gene transfer provided no better glucose control than Ucn2 gene transfer alone and was not associated with hypoglycemia. Metformin alone, Ucn2 gene transfer alone, and metformin + Ucn2 gene transfer together reduced fatty infiltration of the liver. Serum alanine transaminase concentration was elevated in all db/db groups (vs. nondiabetic controls), but the metformin + Ucn2 gene transfer combined group had the lowest alanine transaminase levels. No group differences in fibrosis were detected. In a hepatoma cell line, activation of AMP kinase showed a rank order of combined metformin + Ucn2 peptide > Ucn2 peptide > metformin. We conclude (1) The combination of metformin + Ucn2 gene transfer does not result in hypoglycemia. (2) Ucn2 gene transfer alone provides superior glucose disposal versus metformin alone. (3) The combination of Ucn2 gene transfer and metformin is safe and has additive effects in reducing serum alanine transaminase concentration, activating AMP kinase activity, and increasing Ucn2 expression, but is no more efficacious than Ucn2 gene transfer alone in reducing hyperglycemia. These data indicate that Ucn2 gene transfer is more effective than metformin in the db/db model of insulin resistance and combined treatment with metformin + Ucn2 gene transfer appears to have favorable effects on liver function and Ucn2 expression

The Physiological Basis of Geographic Variation in Rates of Embryonic Development within a Widespread Lizard Species

The duration of embryonic development (e.g., egg incubation period) is a critical life‐history variable because it affects both the amount of time that an embryo is exposed to conditions within the nest and the seasonal timing of hatching. Variation in incubation periods among oviparous reptiles might result from variation in either the amount of embryogenesis completed before laying or the subsequent developmental rates of embryos. Selection on incubation duration could change either of those traits. We examined embryonic development of fence lizards (Sceloporus undulatus) from three populations (Indiana, Mississippi, and Florida) that occur at different latitudes and therefore experience different temperatures and season lengths. These data reveal countergradient variation: at identical temperatures in the laboratory, incubation periods were shorter for lizards from cooler areas. This variation was not related to stage at oviposition; eggs of all populations were laid at similar developmental stages. Instead, embryonic development proceeded more rapidly in cooler‐climate populations, compensating for the delayed development caused by lower incubation temperatures in the field. The accelerated development appears to occur via an increase in heart mass (and, thus, stroke volume) in one population and an increase in heart rate in the other. Hence, superficially similar adaptations of embryonic developmental rate to local conditions may be generated by dissimilar proximate mechanisms

Urocortin 2 Gene Transfer Improves Glycemic Control and Reduces Retinopathy and Mortality in Murine Insulin Deficiency.

Type 1 diabetes affects 20 million patients worldwide. Insulin is the primary and commonly the sole therapy for type 1 diabetes. However, only a minority of patients attain the targeted glucose control and reduced adverse events. We tested urocortin 2 gene transfer as single-agent therapy for insulin deficiency using two mouse models. Urocortin 2 gene transfer reduced blood glucose for months after a single intravenous injection, through increased skeletal muscle insulin sensitivity, increased insulin release in response to glucose stimulation, and increased plasma insulin levels before and during euglycemic clamp. The combined increases in both insulin availability and sensitivity resulted in improved glycemic indices-events that were not anticipated in these insulin-deficient models. In addition, urocortin 2 gene transfer reduced ocular manifestations of long-standing insulin deficiency such as vascular leak and improved retinal function. Finally, mortality was reduced by urocortin 2 gene transfer. The mechanisms for these beneficial effects included increased activities of AMP-activated protein kinase and Akt (protein kinase B) in skeletal muscle, increased skeletal muscle glucose uptake, and increased insulin release. These data suggest that urocortin 2 gene transfer may be a viable therapy for new onset type 1 diabetes and might reduce insulin needs in later stage disease

The role of CXCL10 in the pathogenesis of experimental septic shock

Introduction: The chemokine CXCL10 is produced during infection and inflammation to activate the chemokine receptor CXCR3, an important regulator of lymphocyte trafficking and activation. The goal of this study was to assess the contributions of CXCL10 to the pathogenesis of experimental septic shock in mice. Methods: Septic shock was induced by cecal ligation and puncture (CLP) in mice resuscitated with lactated Ringer's solution and, in some cases, the broad spectrum antibiotic Primaxin. Studies were performed in CXCL10 knockout mice and mice treated with anti-CXCL10 immunoglobulin G (IgG). Endpoints included leukocyte trafficking and activation, core body temperature, plasma cytokine concentrations, bacterial clearance and survival. Results: CXCL10 was present at high concentrations in plasma and peritoneal cavity during CLP-induced septic shock. Survival was significantly improved in CXCL10 knockout (CXCL10KO) mice and mice treated with anti-CXCL10 IgG compared to controls. CXCL10KO mice and mice treated with anti-CXCL10 IgG showed attenuated hypothermia, lower concentrations of interleukin-6 (IL-6) and macrophage inhibitory protein-2 (MIP-2) in plasma and lessened natural killer (NK) cell activation compared to control mice. Compared to control mice, bacterial burden in blood and lungs was lower in CXCL10-deficient mice but not in mice treated with anti-CXCL10 IgG. Treatment of mice with anti-CXCL10 IgG plus fluids and Primaxin at 2 or 6 hours after CLP significantly improved survival compared to mice treated with non-specific IgG under the same conditions. Conclusions: CXCL10 plays a role in the pathogenesis of CLP-induced septic shock and could serve as a therapeutic target during the acute phase of septic shock

Sources of and Solutions to Toxic Metal and Metalloid Contamination in Small Rural Drinking Water Systems: A Rapid Review

Exposure to toxic metals and metalloids (TMs) such as arsenic and lead at levels of concern is associated with lifelong adverse health consequences. As exposure to TMs from paint, leaded gasoline, canned foods, and other consumer products has decreased in recent decades, the relative contribution of drinking water to environmental TM exposure and associated disease burdens has increased. We conducted a rapid review from June to September 2019 to synthesize information on the sources of TM contamination in small rural drinking water systems and solutions to TM contamination from these sources, with an emphasis on actionable evidence applicable to small rural drinking water systems worldwide. We reviewed publications from five databases (ProQuest, PubMed, Web of Science, Embase, and Global Health Library) as well as grey literature from expert groups including WHO, IWA, and others; findings from 61 eligible review publications were synthesized. Identified sources of TMs in included studies were natural occurrence (geogenic), catchment pollution, and corrosion of water distribution system materials. The review found general support for preventive over corrective actions. This review informs a useful planning and management framework for preventing and mitigating TM exposure from drinking water based on water supply characteristics, identified contamination sources, and other context-specific variables

First-principles extrapolation method for accurate CO adsorption energies on metal surfaces

We show that a simple first-principles correction based on the difference between the singlet-triplet CO excitation energy values obtained by DFT and high-level quantum chemistry methods yields accurate CO adsorption properties on a variety of metal surfaces. We demonstrate a linear relationship between the CO adsorption energy and the CO singlet-triplet splitting, similar to the linear dependence of CO adsorption energy on the energy of the CO 2$\pi$* orbital found recently {[Kresse {\em et al.}, Physical Review B {\bf 68}, 073401 (2003)]}. Converged DFT calculations underestimate the CO singlet-triplet excitation energy $\Delta E_{\rm S-T}$, whereas coupled-cluster and CI calculations reproduce the experimental $\Delta E_{\rm S-T}$. The dependence of $E_{\rm chem}$ on $\Delta E_{\rm S-T}$ is used to extrapolate $E_{\rm chem}$ for the top, bridge and hollow sites for the (100) and (111) surfaces of Pt, Rh, Pd and Cu to the values that correspond to the coupled-cluster and CI $\Delta E_{\rm S-T}$ value. The correction reproduces experimental adsorption site preference for all cases and obtains $E_{\rm chem}$ in excellent agreement with experimental results.Comment: Table sent as table1.eps. 3 figure

Preliminary SAR on indole-3-carbinol and related fragments reveals a novel anticancer lead compound against resistant glioblastoma cells

The prognosis for glioblastoma patients is, at best, poor, with the median time of survival after diagnosis measured in months. As such, there is much need for the rapid development of potent and novel treatments. Herein, we report our preliminary findings on the SAR of a series of indole-3-carbinol and related fragments and reveal a potent lead with low micromolar activity against a particularly resistant glioblastoma cell culture, providing a new platform for future development of a new therapy in this area