Medicine and Health Sciences Commons^™

Epc-Exs Improve Astrocyte Survival And Oxidative Stress Through Different Uptaking Pathways In Diabetic Hypoxia Condition, Manasi Suchit Halurkar, Jinju Wang, Shuzhen Chen, Ji Chen Bihl

Pharmacology and Toxicology Faculty Publications

Background: Hyperglycemia contributes to cardiovascular complications in patients with type 2 diabetes. We confirmed that high glucose (HG) induces endothelial dysfunction and cerebral ischemic injury is enlarged in diabetic mice. Stem cell-released exosomes have been shown to protect the brain from ischemic stroke. We have previously shown that endothelial progenitor cells (EPCs)-released exosomes (EPC-EXs) can protect endothelial cells from hypoxia/reoxygenation (H/R) and HG-induced injury. Here, we aim to investigate the effects of EPC-EXs on astrocytes under H/R and HG-induced injury and whether miR-126 enriched EPC-EXs (miR126-EPC-EXs) have enhanced efficacy. Methods: EPC-EX uptake and co-localization were measured by fluorescent microscopy using …

Oxidative Stress Strongly Restricts The Effect Of Codon Choice On The Efficiency Of Protein Synthesis In Escherichia Coli, Lorenzo Eugenio Leiva, Sara Elgamal, Sebastian A. Leidel, Omar Orellana, Michael Ibba, Assaf Katz

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Introduction

The response of enterobacteria to oxidative stress is usually considered to be regulated by transcription factors such as OxyR and SoxR. Nevertheless, several reports have shown that under oxidative stress the levels, modification and aminoacylation of tRNAs may be altered suggesting a role of codon bias in regulation of gene expression under this condition.

Methods

In order to characterize the effects of oxidative stress on translation elongation we constructed a library of 61 plasmids, each coding for the green fluorescent protein (GFP) translationally fused to a different set of four identical codons.

Results

Using these reporters, we observed that …

Escherichia Coli Alanyl-Trna Synthetase Maintains Proofreading Activity And Translational Accuracy Under Oxidative Stress, Arundhati Kavoor, Paul Kelly, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNA synthetases (aaRSs) are enzymes that synthesize aminoacyl-tRNAs to facilitate translation of the genetic code. Quality control by aaRS proofreading and other mechanisms maintains translational accuracy, which promotes cellular viability. Systematic disruption of proofreading, as recently demonstrated for alanyl-tRNA synthetase (AlaRS), leads to dysregulation of the proteome and reduced viability. Recent studies showed that environmental challenges such as exposure to reactive oxygen species can also alter aaRS synthetic and proofreading functions, prompting us to investigate if oxidation might positively or negatively affect AlaRS activity. We found that while oxidation leads to modification of several residues in Escherichia coli AlaRS, unlike …