Cell death mechanism in an isolated wood smoke inhalation induced-ARDS large animal model

Acute respiratory distress syndrome (ARDS) is a lethal disease condition in critically ill patients with a reported mortality rate reaching 45%. The current treatment modalities available for severe ARDS are invasive and carry significant risk for patients. Most published studies involving smoke inhalation utilize another simultaneous injury (such as cutaneous burn) to increase pathology burden of their animal models. This introduces confounding variables to investigations which aim to concentrate on inhalation injury. In this study, we evaluated the potential molecular targets associated with isolated smoke inhalation-induced ARDS. We observed an increase in lung injury score and wet/dry ratio 48h post smoke inhalation together with upregulation of inflammatory markers, IL-1βand IL-6 levels. Furthermore, there was a decrease in phosphorylation of cell survival marker Akt and an increase in pro-apoptotic protein BAX at 48h post smoke inhalation. These results indicate that smoke inhalation induced inflammatory processes resulting in increased apoptosis and decreased cell survival in lung parenchymal cells. Use of this unique model may be of benefit in studying the pathophysiology of inhalation injury and for the development of novel therapeutic strategies.https://digitalcommons.unmc.edu/surp2021/1045/thumbnail.jp

A novel large animal model of smoke inhalation-induced acute respiratory distress syndrome

Background: Acute respiratory distress syndrome (ARDS) is multifactorial and can result from sepsis, trauma, or pneumonia, amongst other primary pathologies. It is one of the major causes of death in critically ill patients with a reported mortality rate up to 45%. The present study focuses on the development of a large animal model of smoke inhalation-induced ARDS in an effort to provide the scientific community with a reliable, reproducible large animal model of isolated toxic inhalation injury-induced ARDS. Methods: Animals (n=21) were exposed to smoke under general anesthesia for 1 to 2 h (median smoke exposure=0.5 to 1 L of oak wood smoke) after the ultrasound-guided placement of carotid, pulmonary, and femoral artery catheters. Peripheral oxygen saturation (SpO2), vital signs, and ventilator parameters were monitored throughout the procedure. Chest x-ray, carotid, femoral and pulmonary artery blood samples were collected before, during, and after smoke exposure. Animals were euthanized and lung tissue collected for analysis 48 h after smoke inhalation. Results: Animals developed ARDS 48 h after smoke inhalation as reflected by a decrease in SpO2 by approximately 31%, PaO2/FiO2 ratio by approximately 208 (50%), and development of bilateral, diffuse infiltrates on chest x-ray. Study animals also demonstrated a significant increase in IL-6 level, lung tissue injury score and wet/dry ratio, as well as changes in other arterial blood gas (ABG) parameters. Conclusions: This study reports, for the first time, a novel large animal model of isolated smoke inhalation-induced ARDS without confounding variables such as cutaneous burn injury. Use of this unique model may be of benefit in studying the pathophysiology of inhalation injury or for development of novel therapeutics

Treatment of the hypertensive patient with microvascular angina

Syndrome X and microvascular angina are a heterogenous group of diseases. Several medications, including angiotensin-converting enzyme inhibitors, β-blockers, and calcium-channel blockers, have been reported to be successful in the treatment of microvascular angina. Control of hypertension and regression of left ventricular hypertrophy are important in controlling symptoms associated with this intriguing problem. The role of nitric oxide and the effects of L-arginine in the pathogenesis and treatment of hypertension and microvascular angina need to be elucidated. Optimal treatment will depend on the appropriate classification and diagnosis of chest pain in patients with hypertension and normal coronary angiograms

Synthesis and single-molecule imaging reveal stereospecific enhancement of binding kinetics by the antitumour eEF1A antagonist SR-A3

Ternatin-family cyclic peptides inhibit protein synthesis by targeting the eukaryotic elongation factor-1α. A potentially related cytotoxic natural product ('A3') was isolated from Aspergillus, but only 4 of its 11 stereocentres could be assigned. Here, we synthesized SR-A3 and SS-A3-two out of 128 possible A3 epimers-and discovered that synthetic SR-A3 is indistinguishable from naturally derived A3. Relative to SS-A3, SR-A3 exhibits an enhanced residence time and rebinding kinetics, as revealed by single-molecule fluorescence imaging of elongation reactions catalysed by eukaryotic elongation factor-1α in vitro. An increased residence time-stereospecifically conferred by the unique β-hydroxyl in SR-A3-was also observed in cells. Consistent with its prolonged duration of action, thrice-weekly dosing with SR-A3 led to a reduced tumour burden and increased survival in an aggressive Myc-driven mouse lymphoma model. Our results demonstrate the potential of SR-A3 as a cancer therapeutic and exemplify an evolutionary mechanism for enhancing cyclic peptide binding kinetics via stereospecific side-chain hydroxylation

An Unbiased Screen Identified the Hsp70-BAG3 Complex as a Regulator of Myosin-Binding Protein C3.

Variants in the gene myosin-binding protein C3 (MYBPC3) account for approximately 50% of familial hypertrophic cardiomyopathy (HCM), leading to reduced levels of myosin-binding protein C3 (MyBP-C), the protein product made by gene MYBPC3. Elucidation of the pathways that regulate MyBP-C protein homeostasis could uncover new therapeutic strategies. Toward this goal, we screened a library of 2,426 bioactive compounds and identified JG98, an allosteric modulator of heat shock protein 70 that inhibits interaction with Bcl-2-associated athanogene (BAG) domain co-chaperones. JG98 reduces MyBP-C protein levels. Furthermore, genetic reduction of BAG3 phenocopies treatment with JG-98 by reducing MYBP-C protein levels.. Thus, an unbiased compound screen identified the heat shock protein 70-BAG3 complex as a regulator of MyBP-C stability