The sequence of morphological intermediates that leads to mammalian autophagosome formation and closure is a crucial yet poorly understood issue. Previous studies have shown that yeast autophagosomes evolve from cup-shaped phagophores with only one closure point, and mammalian studies have inferred that mammalian phagophores also have single openings. Our superresolution microscopy studies in different human cell lines in conditions of basal and nutrient-deprivation-induced autophagy identified autophagosome precursors with multifocal origins that evolved into unexpected finger-like phagophores with multiple openings before becoming more spherical structures. Compatible phagophore structures were observed with whole-mount and conventional electron microscopy. This sequence of events was visualized using advanced SIM 2 superresolution live microscopy. The finger-shaped phagophore apertures remained open when ESCRT function was compromised. The efficient closure of autophagic structures is important for their release from the recycling endosome. This has important implications for understanding how autophagosomes form and capture various cargoes.
Hui Hao,Yao Dang,Sheng Chen,Qian Sun,Ren Kong,Shiyang Cheng,Chunsheng Liu
Triphenyl phosphate (TPHP) is one of the most widely used organophosphate flame retardants (OPFRs) and is frequently detected in a variety of environmental media. Previous studies reported that TPHP had toxic effects on vertebrates, but little toxic information was available in lower trophic aquatic organisms which were more sensitive to the exposure of many toxic substances. In this study, protozoa Tetrahymena thermophila ( T. thermophila ) were exposed to 0, 0.01, 0.17 or 2.35 mg/L TPHP for 5 days to study the effects of sub-chronic exposure on theoretical population, cell viability, cell size and number of cilia. Additionally, the effects of TPHP on gene transcription were assessed by transcriptome sequencing technique (RNA-Seq). Cell viability and number of cilia were significantly reduced in all TPHP exposure groups compared with the control. In addition, exposure to 0.17 or 2.35 mg/L TPHP significantly reduced the theoretical population, circumference and body width, and there was a significant decrease in body length in the 2.35 mg/L exposure group. Comparative transcriptome sequencing identified a total of 4105 up- and 4487 down-regulated genes after exposure to 2.35 mg/L TPHP for 5 days compared with the control. KEGG analysis showed that dysfunction of pathways associated with ribosome, spliceosome, phagosome, proteasome and protein processing in endoplasmic reticulum in this study might be responsible for the toxicity of T. thermophila caused by TPHP. In general, the results indicated that TPHP had an adverse effect on the protozoa T. thermophila .
Non-healing diabetic foot ulcers are the knotty public health issue due to the uncontrolled bacterial infection, prolonged inflammation, and inferior vessel remodeling. In this work, polypyrrole (Ppy) was added into the hybrid hydrogel containing polyvinyl alcohol (PVA), polyethylene glycol (PEG), and hyaluronan (HA) to acquire superior mechanism and photothermal ability. The Ppy composited hybrid hydrogel could effectively kill bacteria through accumulating heat on the hydrogel surface. RNA-Seq analysis shows that the heat accumulation could enhance phagosome of macrophage and M1 activation, which further accelerate bacteria clearance. Benefitting from the bacteria clearance, macrophage could transform its phenotype to M2 in Ppy composited hybrid hydrogel group with near infrared light (NIR) stimulation. The related genes expression in keratinization, keratinocyte differentiation, and establishment of the skin barrier in the skin were up-regulated and collagen and vascular endothelial growth factor (VEGF) expression level are also enhanced. In summary, Ppy composited hybrid hydrogel could effectively solve the issues of infection and poor wound healing in diabetic foot ulcers, making it an ideal candidate dressing for the treatment of chronic wounds.
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