Inhibition of CYP2E1 attenuates myocardial dysfunction in a murine model of insulin resistance through NLRP3-mediated regulation of mitophagy

Insulin resistance leads to myocardial contractile dysfunction and deranged autophagy although the underlying mechanism or targeted therapeutic strategy is still lacking. This study was designed to examine the impact of inhibition of the cytochrome P450 2E1 (CYP2E1) enzyme on myocardial function and mitochondrial autophagy (mitophagy) in an Akt2 knockout model of insulin resistance. Adult wild-type (WT) and Akt2^?/? mice were treated with the CYP2E1 inhibitor diallyl sulfide (100?mg/kg/d, i.p.) for 4?weeks. Cardiac geometry and function were assessed using echocardiographic and IonOptix systems. Western blot analysis was used to evaluate autophagy, mitophagy, inducible NOS (iNOS), and the NLRP3 inflammasome, a multi-protein intracellular pattern recognition receptor complex. Akt2 deletion triggered insulin resistance, compromised cardiac contractile and intracellular Ca²⁺ property, mitochondrial ultrastructural damage, elevated O2^– production, as well as suppressed autophagy and mitophagy, accompanied with elevated levels of NLRP3 and iNOS, the effects of which were significantly attenuated or ablated by diallyl sulfide. In vitro studies revealed that the NLRP3 activator nigericin nullified diallyl sulfide-offered benefit against Akt2 knockout on cardiomyocyte mechanical function and mitophagy (using Western blot and colocalization of GFP-LC3 and MitoTracker Red). Moreover, inhibition of iNOS but not mitochondrial ROS production attenuated Akt2 deletion-induced activation of NLRP3, substantiating a role for iNOS-mediated NLRP3 in insulin resistance-induced changes in mitophagy and cardiac dysfunction. In conclusion, these data depict that insulin resistance through CYP2E1 may contribute to the pathogenesis of myopathic changes including myocardial contractile dysfunction, oxidative stress and mitochondrial injury, possibly through activation of iNOS and NLRP3 signaling.     

Molecular basis of cross‐species ACE2 interactions with SARS‐CoV‐2‐like viruses of pangolin origin

Correction to: The EMBO Journal (2021) 40: e107786. DOI 10.15252/embj.2021107786 | Published online 8 June 2021The authors would like to add three references to the paper: Starr et al and Zahradník et al also reported that the Q498H or Q498R mutation has enhanced binding affinity to ACE2; and Liu et al reported on the binding of bat coronavirus to ACE2.Starr et al and Zahradník et al have now been cited in the Discussion section, and the following sentence has been corrected from:“According to our data, the SARS‐CoV‐2 RBD with Q498H increases the binding strength to hACE2 by 5‐fold, suggesting the Q498H mutant is more ready to interact with human receptor than the wildtype and highlighting the necessity for more strict control of virus and virus‐infected animals”.to“Here, according to our data and two recently published papers, the SARS‐CoV‐2 RBD with Q498H or Q498R increases the binding strength to hACE2 (Starr et al, 2020; Zahradník et al, 2021), suggesting the mutant with Q498H or Q498R is more ready to interact with human receptor than the wild type and highlighting the necessity for more strict control of virus and virus‐infected animals”.The Liu et al citation has been added to the following sentence:“In another paper published by our group recently, RaTG13 RBD was found to bind to hACE2 with much lower binding affinity than SARS‐CoV‐2 though RaTG13 displays the highest whole‐genome sequence identity (96.2%) with the SARS‐CoV‐2 (Liu et al, 2021)”.Additionally, the authors have added the GISAID accession IDs to the sequence names of the SARS‐CoV‐2 in two human samples (Discussion section). To make identification unambiguous, the sequence names have been updated from “SA‐lsf‐27 and SA‐lsf‐37” to “GISAID accession ID: EPI_ISL_672581 and EPI_ISL_672589”.Lastly, the authors declare in the Materials and Methods section that all experiments employed SARS‐CoV‐2 pseudovirus in cultured cells. These experiments were performed in a BSL‐2‐level laboratory and approved by Science and Technology Conditions Platform Office, Institute of Microbiology, Chinese Academy of Sciences.These changes are herewith incorporated into the paper.     

适于工程教育的生物化学PBL教学案例设计

工程教育是我国高等教育的重要组成部分,随着新工科人才培养内涵的不断深化,全方位开展课程改革,提高工科人才培养质量正当其时。为了突出新工科人才培养的特色,专业课和实习实践类课程正在成为课程教学改革的重点。但是,在专业基础课中如何突出工科特色人才培养的实践亟待探索。本文以生物化学课程为例,采用问题引导式教学方法,选择合适的教学案例,从科学与技术问题出发探索教学设计,引导学生凝练问题、分析问题并解决问题。实现引导学生从“被动式”到“主动式”学习的转变,提升学生思辨能力的同时,突出科学与技术的工程化应用,并为持续甚至终生学习奠定基础,为新工科背景下应用型人才培养提供参考和借鉴。     

scGET: Predicting Cell Fate Transition During Early Embryonic Development by Single-cell Graph Entropy

During early embryonic development, cell fate commitment represents a critical transition or"tipping point"of embryonic differentiation, at which there is a drastic and qualitative shift of the cell populations. In this study, we presented a computational approach, scGET, to explore the gene–gene associations based on single-cell RNA sequencing (scRNA-seq) data for critical transition prediction. Specifically, by transforming the gene expression data to the local network entropy, the single-cell graph entropy (SGE) value quantitatively characterizes the stability and criticality of gene regu-latory networks among cell populations and thus can be employed to detect the critical signal of cell fate or lineage commitment at the single-cell level. Being applied to five scRNA-seq datasets of embryonic differentiation, scGET accurately predicts all the impending cell fate transitions. After identifying the"dark genes"that are non-differentially expressed genes but sensitive to the SGE value, the underlying signaling mechanisms were revealed, suggesting that the synergy of dark genes and their downstream targets may play a key role in various cell development processes. The application in all five datasets demonstrates the effectiveness of scGET in analyzing scRNA-seq data from a network perspective and its potential to track the dynamics of cell differentiation. The source code of scGET is accessible at https://github.com/zhongjiayuna/scGET_Project.     

Melanoma chondroitin sulfate proteoglycan regulates matrix metalloproteinase-dependent human melanoma invasion into type I collagen

Tumor cell adhesion and proteolysis of the extracellular matrix proteins surrounding the cells are tightly linked processes in tumor invasion. In this study, we sought to identify components of the cell surface of a vertical growth phase melanoma cell line, WM1341D, that mediate invasive cellular behavior. We determined by antisense inhibition that melanoma chondroitin sulfate proteoglycan (MCSP) and membrane-type 3 matrix metalloproteinase (MT3-MMP) expressed on WM1341D are required for invasion of type I collagen and degradation of type I gelatin. MT3-MMP co-immunoprecipitated with MCSP in WM1341D melanoma cells cultured on type I collagen or laminin. The association between MT3-MMP and MCSP was largely disrupted by removing chondroitin sulfate glycosaminoglycan (CS) from the cell surface, suggesting CS could mediate the association between the two cell surface core proteins. Recombinant MT3-MMP and MT3-MMP from whole cell lysates of WM1341D cells were specifically eluted from CS- conjugated affinity columns. The results indicate that MT3-MMP possesses the potential to promote melanoma invasion and proteolysis and that the formation of a complex between MT3-MMP and MCSP may be a crucial step in activating these processes.     

Bilineal disease and trans-heterozygotes in autosomal dominant polycystic kidney disease

In searching for a putative third gene for autosomal dominant polycystic kidney disease (ADPKD), we studied the genetic inheritance of a large family (NFL10) previously excluded from linkage to both the PKD1 locus and the PKD2 locus. We screened 48 members of the NFL10 pedigree, by ultrasonography, and genotyped them, with informative markers, at both the PKD1 locus and the PKD2 locus. Twenty-eight of 48 individuals assessed were affected with ADPKD. Inspection of the haplotypes of these individuals suggested the possibility of bilineal disease from independently segregating PKD1 and PKD2 mutations. Using single-stranded conformational analysis, we screened for and found a PKD2 mutation (i.e., 2152delA; L736X) in 12 affected pedigree members. Additionally, when the disease status of these individuals was coded as "unknown" in linkage analysis, we also found, with markers at the PKD1 locus, significant LOD scores (i.e., >3.0). These findings strongly support the presence of a PKD1 mutation in 15 other affected pedigree members, who lack the PKD2 mutation. Two additional affected individuals had trans-heterozygous mutations involving both genes, and they had renal disease that was more severe than that in affected individuals who had either mutation alone. This is the first documentation of bilineal disease in ADPKD. In humans, trans-heterozygous mutations involving both PKD1 and PKD2 are not necessarily embryonically lethal. However, the disease associated with the presence of both mutations appears to be more severe than the disease associated with either mutation alone. The presence of bilineal disease as a confounder needs to be considered seriously in the search for the elusive PKD3 locus.     

Activation of regulatory cells suppresses experimental allergic encephalomyelitis via secretion of IL-10

Suppression of CD4+ Th1 cell-mediated autoimmune disease via immune deviation is an attractive potential therapeutic approach. CD4+ Th2 T cells specific for myelin basic protein, induced by immunization of young adult male SJL mice, suppress or modify the progression of CNS autoimmune disease. This report demonstrates that activation of non-neuroantigen-specific Th2 cells is sufficient to suppress both clinical and histological experimental allergic encephalomyelitis (EAE). Th2 cells were obtained following immunization of male SJL mice with keyhole limpet hemocyanin. Transfer of these cells did not modify EAE, a model of human multiple sclerosis, in the absence of cognate Ag. Disease suppression was obtained following adoptive transfer and subcutaneous immunization. Suppression was not due to the deletion of myelin basic protein-specific T cells, but resulted from the presence of IL-10 as demonstrated by the inhibition of Th2-mediated EAE suppression via passive transfer with either anti-IL-10 or anti-IL-10R mAb. These data demonstrate that peripheral activation of a CD4+ Th2 population specific for an Ag not expressed in the CNS modifies CNS autoimmune disease via IL-10. These data suggest that either peripheral activation or direct administration of IL-10 may be of benefit in treating Th1-mediated autoimmune diseases.