Insights into the function of ESCRT and its role in enveloped virus infection

The endosomal sorting complex required for transport (ESCRT) is an essential molecular machinery in eukaryotic cells that facilitates the invagination of endosomal membranes, leading to the formation of multivesicular bodies (MVBs). It participates in various cellular processes, including lipid bilayer remodeling, cytoplasmic separation, autophagy, membrane fission and re-modeling, plasma membrane repair, as well as the invasion, budding, and release of certain enveloped viruses. The ESCRT complex consists of five complexes, ESCRT-0 to ESCRT-III and VPS4, along with several accessory proteins. ESCRT-0 to ESCRT-II form soluble complexes that shuttle between the cytoplasm and membranes, mainly responsible for recruiting and transporting membrane proteins and viral particles, as well as recruiting ESCRT-III for membrane neck scission. ESCRT-III, a soluble monomer, directly participates in vesicle scission and release, while VPS4 hydrolyzes ATP to provide energy for ESCRT-III complex disassembly, enabling recycling. Studies have confirmed the hijacking of ESCRT complexes by enveloped viruses to facilitate their entry, replication, and budding. Recent research has focused on the interaction between various components of the ESCRT complex and different viruses. In this review, we discuss how different viruses hijack specific ESCRT regulatory proteins to impact the viral life cycle, aiming to explore commonalities in the interaction between viruses and the ESCRT system

Analysis of Gene Regulatory Networks in the Mammalian Circadian Rhythm

Circadian rhythm is fundamental in regulating a wide range of cellular, metabolic, physiological, and behavioral activities in mammals. Although a small number of key circadian genes have been identified through extensive molecular and genetic studies in the past, the existence of other key circadian genes and how they drive the genomewide circadian oscillation of gene expression in different tissues still remains unknown. Here we try to address these questions by integrating all available circadian microarray data in mammals. We identified 41 common circadian genes that showed circadian oscillation in a wide range of mouse tissues with a remarkable consistency of circadian phases across tissues. Comparisons across mouse, rat, rhesus macaque, and human showed that the circadian phases of known key circadian genes were delayed for 4–5 hours in rat compared to mouse and 8–12 hours in macaque and human compared to mouse. A systematic gene regulatory network for the mouse circadian rhythm was constructed after incorporating promoter analysis and transcription factor knockout or mutant microarray data. We observed the significant association of cis-regulatory elements: EBOX, DBOX, RRE, and HSE with the different phases of circadian oscillating genes. The analysis of the network structure revealed the paths through which light, food, and heat can entrain the circadian clock and identified that NR3C1 and FKBP/HSP90 complexes are central to the control of circadian genes through diverse environmental signals. Our study improves our understanding of the structure, design principle, and evolution of gene regulatory networks involved in the mammalian circadian rhythm

Versatile Roles of the Chromatin Remodeler CHD7 during Brain Development and Disease

CHD7 (Chromo-Helicase-DNA binding protein 7) protein is an ATP-dependent chromatin remodeler. Heterozygous mutation of the CHD7 gene causes a severe congenital disease known as CHARGE syndrome. Most CHARGE syndrome patients have brain structural anomalies, implicating an important role of CHD7 during brain development. In this review, we summarize studies dissecting developmental functions of CHD7 in the brain and discuss pathogenic mechanisms behind neurodevelopmental defects caused by mutation of CHD7. As we discussed, CHD7 protein exhibits a remarkably specific and dynamic expression pattern in the brain. Studies in human and animal models have revealed that CHD7 is involved in multiple developmental lineages and processes in the brain. Mechanistically, CHD7 is essential for neural differentiation due to its transcriptional regulation in progenitor cells

Predicting Workability of a Low-Cost Powder Metallurgical Ti–5Al–2Fe–3Mo Alloy Using Constitutive Modeling and Processing Map

A low-cost titanium alloy (Ti–5Al–2Fe–3Mo wt.%) was designed and fabricated by blended elemental powder metallurgy (BEPM) process. The high-temperature deformation behavior of the powder metallurgical Ti–5Al–2Fe–3Mo wt.% (PM-TiAlFeMo) alloy was investigated by hot compression tests at temperatures ranging from 700 to 1000 °C and strain rates ranging from 0.001 to 10 s−1. The flow curves were employed to develop the Arrhenius-type constitutive model in consideration of effects of deformation temperature, strain rate, and flow stress. The value of activation energy (Q) was determined as 413.25 kJ/mol. In order to describe the workability and predict the optimum hot processing parameters of the PM-TiAlFeMo alloy, the processing map has been established based on the true stress–true strain curves and power dissipation efficiency map. Moreover, microstructure observations match well with the analyses about deformation mechanisms, revealing that dynamic recovery and dynamic recrystallization are dominant softening mechanisms at relatively high temperatures. However, the kinking and breaking of microstructure prefer to occur at relatively low temperatures

Elevated-temperature tensile deformation and fracture behavior of particle-reinforced PM 8009Al matrix composite

Tensile tests of 8009Al alloy reinforced with SiC and Al₂O₃ particles fabricated by powder metallurgy (PM) were conducted at temperatures of 250–350°C and strain rates of 0.001–0.1 s⁻¹. The ultimate tensile strength and yield strength of the samples decreased while the temperature and strain rate increased. The elongation slightly decreased at first and then increased with growing temperature because of the medium-temperature brittleness of the alloy matrix. When the strain rate was 0.1 s⁻¹, the elongation of the 8009Al/Al₂O₃ composites always decreased with an increase in temperature because of the poorly coordinated deformation and weak bonding between the matrix and Al₂O₃ particles at such a high strain rate. The work-hardening rates of the composites sharply increased to maxima and then decreased rapidly as the strain increased. Meanwhile, the 8009Al/SiCₚ composites displayed superior UTS, YS, elongation, and work-hardening rates than those of the 8009Al/Al₂O₃ composites under the same conditions. Compared to 8009Al alloys reinforced with spherical Al₂O₃ particle, 8009Al alloys reinforced with irregular SiC particles exhibited a better strengthening effect. The fracture mechanism of the 8009Al/SiCₚ composites was mainly ductile, while that of the 8009Al/Al₂O₃ composites was primarily debonding at the matrix–particle interfaces in a brittle mode

CTSB and CTSD exacerbate NDV-induced LMP by inducing the generation of ROS.

(A) Intracellular ROS levels were measured by flow cytometry using DCFH-DA staining in HeLa cells infected with Herts/33 at 0.01 MOI for different timepoints or mock-infected. (B) HeLa cells were transfected with si-CTSB, si-CTSD, or si-NC for 48h, or mock-transfected, and intracellular ROS levels were measured by flow cytometry using DCFH-DA staining following infection with Herts/33 at 0.01 MOI or mock-infection for 12h. (C) HeLa cells were pretreated with LLoMe (500 nM), DMSO, or mock-untreated for 3h, respectively. Subsequently, the intracellular ROS levels were measured by flow cytometry using DCFH-DA staining cells following infection with Herts/33 at 0.01 MOI or mock-infection for 24h. (D) HeLa cells were treated with NAC (2 mM) for 24h after absorption with Herts/33 at 0.01 MOI for 1h. LMP levels were evaluated by confocal microscopy using indicated antibodies. Scale bars, 20 μm. Manders’ Colocalization Coefficients of galectin 3 with LAMP1 were quantified by ImageJ software and shown on the right. Error bars represent SDs for triplicate analyses of three independent experiments (A-C) or SDs for 15 cells (D). All significance analyses were assessed using one-way ANOVA with Dunnett’s multiple comparisons test.</p

The sialidase activity of the HN protein mediates the deglycosylation and degradation of LAMP1 and LAMP2.

(A) Western blotting analysis of LAMP1 and LAMP2 deglycosylation and degradation in HeLa cells transfected with plasmid expressing HN protein and treated with Peramivir (30 μg/mL) or Zanamivir (20 μg/mL) at the indicated time points post-transfection. (B&C) HeLa cells were transfected with plasmids expressing HN protein or mock-transfected. Then the cells were treated with Peramivir (30 μg/mL) or Zanamivir (20 μg/mL) or DMSO or untreated for 48h. The LMP level was observed by confocal microscopy using anti-galectin 3 (green) and anti-LAMP1 (red) antibodies. Scale bars, 20 μm (B). Manders’ Colocalization Coefficients of galectin 3 with LAMP1 are quantified by ImageJ software and shown in (C). (G) Sialidase activity was measured in HeLa cells transfected with the indicated plasmids for 48h and is presented as relative change to the cells transfected with plasmids expressing wild-type HN. The red dotted line indicates the difference threshold. (F) Western blotting analysis of LAMP1 and LAMP2 deglycosylation and degradation in HeLa cells transfected with the indicated plasmids or mock-transfected for 48h. (D&E) The interaction between HN and LAMP1 (D) or LAMP2 (E) in HeLa cells was detected by an immunoprecipitation assay with anti-flag or control IgG antibodies after transfection with indicated plasmids for 48h. (H) The LMP level was observed by confocal microscopy using anti-galectin 3 (green) and anti-LAMP1 (red) antibodies following transfection with the indicated plasmids or mock-transfected for 48h. Scale bars, 20 μm. (I) Manders’ Colocalization Coefficients of galectin 3 with LAMP1 are calculated by ImageJ software. (J) The apoptosis rate was measured by AnnexinV-FITC/PI staining using flow cytometry following transfection with indicated plasmids or mock-transfection for 48h. Error bars are SDs for a triplicate analysis of three independent experiments (G&J), or SDs for 15 cells (C&H). All significance analyses were assessed using One-way ANOVA with Dunnett’s multiple comparisons test.</p