You are here

Translational Science Laboratory

Permalink: https://diginole.lib.fsu.edu/islandora/object/fsu:translational_science_laboratory

Discovery and evaluation of inhibitor of LARP6 as specific antifibrotic compound
Discovery and evaluation of inhibitor of LARP6 as specific antifibrotic compound
Fibrosis is characterized by excessive production of type I collagen. Biosynthesis of type I collagen in fibrosis is augmented by binding of protein LARP6 to the 5’ stem-loop structure (5’SL), which is found exclusively in type I collagen mRNAs. A high throughput screen was performed to discover inhibitors of LARP6 binding to 5’SL, as potential antifibrotic drugs. The screen yielded one compound (C9) which was able to dissociate LARP6 from 5’ SL RNA in vitro and to inactivate the binding of endogenous LARP6 in cells. Treatment of hepatic stellate cells (liver cells responsible for fibrosis) with nM concentrations of C9 reduced secretion of type I collagen. In precision cut liver slices, as an ex vivo model of hepatic fibrosis, C9 attenuated the profibrotic response at 1 μM. In prophylactic and therapeutic animal models of hepatic fibrosis C9 prevented development of fibrosis or hindered the progression of ongoing fibrosis when administered at 1 mg/kg. Toxicogenetics analysis revealed that only 42 liver genes changed expression after administration of C9 for 4 weeks, suggesting minimal off target effects. Based on these results, C9 represents the first LARP6 inhibitor with significant antifibrotic activity., Keywords: fibrosis, therapy, drug screening, Publication Note: The version of record can be found at https://www.doi.org/10.1038/s41598-018-36841-y.
Myosin Rod Hypophosphorylation and CB Kinetics in Papillary Muscles from a TnC-A8V KI Mouse Model.
Myosin Rod Hypophosphorylation and CB Kinetics in Papillary Muscles from a TnC-A8V KI Mouse Model.
The cardiac troponin C (TnC)-A8V mutation is associated with hypertrophic and restrictive cardiomyopathy (HCM and RCM) in human and mice. The residue affected lies in the N-helix, a region known to affect Ca-binding affinity to the N-terminal domain. Here we report on the functional effects of this mutation in skinned papillary muscle fibers from homozygous knock-in TnC-A8V mice. Muscle fibers from left ventricle were activated at 25°C under the ionic conditions of working cardiomyocytes. The pCa-tension relationship showed a 3× increase in Ca-sensitivity and a decrease (0.8×) in cooperativity (n) in mutant fibers. The elementary steps of the cross-bridge (CB) cycle were investigated by sinusoidal analysis. The ATP study revealed that there is no significant change in the affinity of ATP (K) for the myosin head. In TnC-A8V mutant fibers, the CB detachment rate (k) and its equilibrium constant (K) increased (1.5×). The phosphate study revealed that rate constant of the force-generation step (k) decreased (0.5×), reversal step (k) increased (2×), and the phosphate-release step (1/K) increased (2×). Pro-Q Diamond staining of the skinned fibers samples revealed no significant changes in total phosphorylation of multiple sarcomeric proteins. Further investigation using liquid chromatography-tandem mass spectrometry revealed hypophosphorylation of the rod domain of myosin heavy chain in TnC-A8V mutant fibers compared to wild-type. Immunoblotting confirmed the results observed in the mass spectrometry analysis. The results suggest perturbed CB kinetics-possibly caused by changes in the α-myosin heavy chain phosphorylation profile-as a novel mechanism, to our knowledge, by which a mutation in TnC can have rippling effects in the myofilament and contribute to the pathogenesis of HCM/RCM., Grant Number: K99 HL103840, R00 HL103840, R01 HL128683, Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406373.
Oxidative Stress in Metabolic Disorders
Oxidative Stress in Metabolic Disorders
Keywords: adipose-tissue, antioxidant supplementation, dysfunction, galectin-3, obesity, strategies, Publication Note: The publisher’s version of record is available at http://www.dx.doi.org/10.1155/2016/9137629