Double deletion of PINK1 and Parkin impairs hepatic mitophagy and exacerbates acetaminophen-induced liver injury in mice

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.Mitochondria damage plays a critical role in acetaminophen (APAP)-induced necrosis and liver injury. Cells can adapt and protect themselves by removing damaged mitochondria via mitophagy. PINK1-Parkin pathway is one of the major pathways that regulate mitophagy but its role in APAP-induced liver injury is still elusive. We investigated the role of PINK1-Parkin pathway in hepatocyte mitophagy in APAP-induced liver injury in mice. Wild-type (WT), PINK1 knockout (KO), Parkin KO, and PINK1 and Parkin double KO (DKO) mice were treated with APAP for different time points. Liver injury was determined by measuring serum alanine aminotransferase (ALT) activity, H&E staining as well as TUNEL staining of liver tissues. Tandem fluorescent-tagged inner mitochondrial membrane protein Cox8 (Cox8-GFP-mCherry) can be used to monitor mitophagy based on different pH stability of GFP and mCherry fluorescent proteins. We overexpressed Cox8-GFP-mCherry in mouse livers via tail vein injection of an adenovirus Cox8-GFP-mCherry. Mitophagy was assessed by confocal microscopy for Cox8-GFP-mCherry puncta, electron microscopy (EM) analysis for mitophagosomes and western blot analysis for mitochondrial proteins. Parkin KO and PINK1 KO mice improved the survival after treatment with APAP although the serum levels of ALT were not significantly different among PINK1 KO, Parkin KO and WT mice. We only found mild defects of mitophagy in PINK1 KO or Parkin KO mice after APAP, and improved survival in PINK1 KO and Parkin KO mice could be due to other functions of PINK1 and Parkin independent of mitophagy. In contrast, APAP-induced mitophagy was significantly impaired in PINK1-Parkin DKO mice. PINK1-Parkin DKO mice had further elevated serum levels of ALT and increased mortality after APAP administration. In conclusion, our results demonstrated that PINK1-Parkin signaling pathway plays a critical role in APAP-induced mitophagy and liver injury.NIH R01 AA 020518NIH R01 DK 102142NIH U01 AA 024733NIH P20 GM 103549NIH P30 GM 118247NIH COBRE grant 9P20GM104936NIH S10RR02756

Comparative Analysis of the Genomes of Two Field Isolates of the Rice Blast Fungus Magnaporthe oryzae.

Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases of rice worldwide. The fungal pathogen is notorious for its ability to overcome host resistance. To better understand its genetic variation in nature, we sequenced the genomes of two field isolates, Y34 and P131. In comparison with the previously sequenced laboratory strain 70-15, both field isolates had a similar genome size but slightly more genes. Sequences from the field isolates were used to improve genome assembly and gene prediction of 70-15. Although the overall genome structure is similar, a number of gene families that are likely involved in plant-fungal interactions are expanded in the field isolates. Genome-wide analysis on asynonymous to synonymous nucleotide substitution rates revealed that many infection-related genes underwent diversifying selection. The field isolates also have hundreds of isolate-specific genes and a number of isolate-specific gene duplication events. Functional characterization of randomly selected isolate-specific genes revealed that they play diverse roles, some of which affect virulence. Furthermore, each genome contains thousands of loci of transposon-like elements, but less than 30% of them are conserved among different isolates, suggesting active transposition events in M. oryzae. A total of approximately 200 genes were disrupted in these three strains by transposable elements. Interestingly, transposon-like elements tend to be associated with isolate-specific or duplicated sequences. Overall, our results indicate that gain or loss of unique genes, DNA duplication, gene family expansion, and frequent translocation of transposon-like elements are important factors in genome variation of the rice blast fungus

Identification of mutations in porcine STAT5A that contributes to the transcription of CISH

Identification of causative genes or genetic variants associated with phenotype traits benefits the genetic improvement of animals. CISH plays a role in immunity and growth, however, the upstream transcriptional factors of porcine CISH and the genetic variations in these factors remain unclear. In this study, we firstly identified the minimal core promoter of porcine CISH and confirmed the existence of STATx binding sites. Overexpression and RT-qPCR demonstrated STAT5A increased CISH transcriptional activity (P < 0.01) and mRNA expression (P < 0.01), while GATA1 inhibited CISH transcriptional activity (P < 0.01) and the following mRNA expression (P < 0.05 or P < 0.01). Then, the putative functional genetic variations of porcine STAT5A were screened and a PCR-SSCP was established for genotype g.508A>C and g.566C>T. Population genetic analysis showed the A allele frequency of g.508A>C and C allele frequency of g.566C>T was 0.61 and 0.94 in Min pigs, respectively, while these two alleles were fixed in the Landrace population. Statistical analysis showed that Min piglets with CC genotype at g.566C>T or Hap1: AC had higher 28-day body weight, 35-day body weight, and ADG than TC or Hap3: CT animals (P < 0.05, P < 0.05). Further luciferase activity assay demonstrated that the activity of g.508A>C in the C allele was lower than the A allele (P < 0.05). Collectively, the present study demonstrated that STAT5A positively regulated porcine CISH transcription, and SNP g.566C>T in the STAT5A was associated with the Min piglet growth trait

17β-Estradiol Enhances Schwann Cell Differentiation via the ERβ-ERK1/2 Signaling Pathway and Promotes Remyelination in Injured Sciatic Nerves

Remyelination is critical for nerve regeneration. However, the molecular mechanism involved in remyelination is poorly understood. To explore the roles of 17β-estradiol (E2) for myelination in the peripheral nervous system, we used a co-culture model of rat dorsal root ganglion (DRG) explants and Schwann cells (SCs) and a regeneration model of the crushed sciatic nerves in ovariectomized (OVX) and non-ovariectomized (non-OVX) rats for in vitro and in vivo analysis. E2 promoted myelination by facilitating the differentiation of SCs in vitro, which could be inhibited by the estrogen receptors (ER) antagonist ICI182780, ERβ antagonist PHTPP, or ERK1/2 antagonist PD98059. This suggests that E2 accelerates SC differentiation via the ERβ-ERK1/2 signaling. Furthermore, E2 promotes remyelination in crushed sciatic nerves of both OVX and non-OVX rats. Interestingly, E2 also significantly increased the expression of the lysosome membrane proteins LAMP1 and myelin protein P0 in the regenerating nerves. Moreover, P0 has higher degree of colocalization with LAMP1 in the regenerating nerves. Taking together, our results suggest that E2 enhances Schwann cell differentiation and further myelination via the ERβ-ERK1/2 signaling and that E2 increases the expression of myelin proteins and lysosomes in SCs to promotes remyelination in regenerating sciatic nerves

Neovascularization-directed bionic eye drops for noninvasive renovation of age-related macular degeneration

The current treatment of wet age-related macular degeneration (wAMD) relies on monthly intravitreal or intravenously injection of vascular endothelial growth factor (VEGF) inhibitor or photodynamic (PDT) agents to inhibit choroidal neovascularization. However, traumatic local therapy and exogenous long-distance fundus drug delivery often lead to secondary eye damage, low treatment efficiency, and immunogenic inflammation. Herein, inspired by the natural neovascular targeting ability of endogenous low-density lipoproteins (LDL), a noninvasive bionic nano-eye-drop with enhanced ocular penetrability and lesion recognizability is developed for enabling the PDT treatment of wAMD. Verteporfin (VP) as a laser-induced PDT agent is protected inside the hydrophobic core of reconstituted LDL (rLDL) vectors. 5-carboxyfluorescein (FAM) conjugated ste-penetratin (PEN, a transmembrane peptide) is anchored on the surface of the rLDL carrier, which enabled the nanoparticles (PEN-rLDL-VP) to cross the blood-retina barrier to realizing visual therapy. Following instillation, PEN-rLDL-VP can effectively deliver VP into neovascular that overexpress LDL receptors, which can respond to laser-induced PDT. Only with a single dose of the eye-drop and laser-induced PDT, the VEGF and proinflammatory intercellular adhesion molecule-1 (ICAM-1) proteins are significantly down-regulated in vivo, which implicates the neovascular inhibition and inflammation alleviation. This study presents an attractive non-invasive strategy for the PDT of wAMD

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Regulation of the homeostasis of hepatic endoplasmic reticulum and cytochrome P450 enzymes by autophagy

The endoplasmic reticulum (ER) is an intracellular organelle consisting of a continuous network of membranes. In the liver, the ER is highly active in protein modification, lipid metabolism, and xenobiotic detoxification. Maintaining these complicated processes requires elaborate control of the ER lumen environment as well as the ER volume. Increasing evidence suggests that autophagy plays a critical role in regulating the homeostasis of hepatic ER contents and levels of cytochrome P450 (CYP) enzymes via selective ER-phagy. This review will provide an overview of ER-phagy, summarizing the possible roles of recently identified ER-phagy receptor proteins in regulating the homeostasis of hepatic ER and CYP enzymes as well as outlining the various implications of ER-phagy in ER-related liver diseases. Keywords: Alcoholic liver disease, Endoplasmic reticulum (ER)-phagy, Endoplasmic reticulum (ER) stress, Cytochrome P450 (CYP) enzymes, Liver diseases, Non-alcoholic fatty liver disease (NAFLD), Non-alcoholic steatohepatitis (NASH

Land Use/Cover Dynamics in Response to Changes in Environmental and Socio-Political Forces in the Upper Reaches of Yangtze River, China

Land use/cover change (LUCC), which results from the complex interaction of social, ecological and geophysical processes, is a major issue and the main cause of global environmental change. This study analyzed the land use/cover dynamics and their environmental and socio-political forces in the upper reaches of Yangtze River from 1980 to 2000 by using remote sensing, climatic and socio-economic data from both research institutes and government departments. The results indicated that there had been significant land use/cover changes between 1980 and 2000 in the study area, which were characterized by a severe replacement of cropland and woodland with grassland and built-up land. The transition matrices highlight the dominant dynamic events and the internal conversions between land use/cover types during the study period and reveal two distinct transition phases. Land use/cover changes in the upper reaches of Yangtze River during 1980 to 2000, while restricted by environmental attributes, were strongly driven by socio-political factors. However, excessively pursuing higher land use benefits likely results in serious environmental degradation. This study suggests that the restructuring of land use should be based on land suitability and sustainable protection of fragile environment in the upper reaches of Yangtze River. A thorough comprehension of historical changes will enhance our capability to predict future land use change and contribute to effective management strategies and policies for the rational land use