When the brain is in a pathological state, the content of lipid droplets (LDs), the lipid storage organelles, is increased, particularly in glial cells, but rarely in neurons. The biology and mechanisms leading to LD accumulation in astrocytes, glial cells with key homeostatic functions, are poorly understood. We imaged fluorescently labeled LDs by microscopy in isolated and brain tissue rat astrocytes and in glia‐like cells in Drosophila brain to determine the (sub)cellular localization, mobility, and content of LDs under various stress conditions characteristic for brain pathologies. LDs exhibited confined mobility proximal to mitochondria and endoplasmic reticulum that was attenuated by metabolic stress and by increased intracellular Ca2+, likely to enhance the LD–organelle interaction imaged by electron microscopy. When de novo biogenesis of LDs was attenuated by inhibition of DGAT1 and DGAT2 enzymes, the astrocyte cell number was reduced by ~40%, suggesting that in astrocytes LD turnover is important for cell survival and/or proliferative cycle. Exposure to noradrenaline, a brain stress response system neuromodulator, and metabolic and hypoxic stress strongly facilitated LD accumulation in astrocytes. The observed response of stressed astrocytes may be viewed as a support for energy provision, but also to be neuroprotective against the stress‐induced lipotoxicity.
17 December 2020 in Frontiers in Bioengineering and Biotechnology
Progress in the understanding of the biology of perinatal tissues has contributed to the breakthrough revelation of the therapeutic effects of perinatal derivatives (PnD), namely birth-associated tissues, cells, and secreted factors. The significant knowledge acquired in the past two decades, along with the increasing interest in perinatal derivatives, fuels an urgent need for the precise identification of PnD and the establishment of updated consensus criteria policies for their characterization. The aim of this review is not to go into detail on preclinical or clinical trials, but rather we address specific issues that are relevant for the definition/characterization of perinatal cells, starting from an understanding of the development of the human placenta, its structure, and the different cell populations that can be isolated from the different perinatal tissues. We describe where the cells are located within the placenta and their cell morphology and phenotype. We also propose nomenclature for the cell populations and derivatives discussed herein. This review is a joint effort from the COST SPRINT Action (CA17116), which broadly aims at approaching consensus for different aspects of PnD research, such as providing inputs for future standards for the processing andin vitrocharacterization and clinical application of PnD.
Escherichia coli strains frequently are isolated from skin and soft tissue infections (SSTI); however, their virulence potential has not yet been extensively studied. In the present study, we characterized 102 E. coli SSTI strains isolated mostly from surgical and traumatic wounds, foot ulcers, and decubitus. The strains were obtained from the Institute of Microbiology and Immunology, University of Ljubljana, Slovenia. Phylogenetic backgrounds, virulence factors (VFs), and antibiotic resistance profiles were determined. Correlations between VFs and phylogenetic groups were established and analyzed with regard to patient factors. Further, the associations of the three most prevalent antibiotic resistance patterns with virulence potential were analyzed. Our results showed that the majority of the studied strains (65%) belonged to the B2 phylogenetic group. The most prevalent VF was ompT (80%), while toxin genes cnf1 and hlyA were found with prevalences of 32 and 30%, respectively. None of the investigated bacterial characteristics were significantly associated with patient gender, age, type of infection, or immunodeficiency. The most prevalent antibiotic resistance pattern was resistance to ampicillin (46%), followed by resistance to tetracycline (25%) and fluoroquinolones (21%). Strains resistant to ciprofloxacin exhibited a significantly reduced prevalence of cnf1 ( P < 0.05) and usp ( P < 0.01). Our study revealed that E. coli isolates from SSTIs exhibit a remarkable virulence potential that is comparable to that of E. coli isolates from urinary tract infections and bacteremia.