Cholesterol transport through lysosome-peroxisome membrane contacts.

Cholesterol is dynamically transported among organelles, which is essential for multiple cellular functions. However, the mechanism underlying intracellular cholesterol transport has remained largely unknown. We established an amphotericin B-based assay enabling a genome-wide shRNA screen for delayed LDL-cholesterol transport and identified 341 hits with particular enrichment of peroxisome genes, suggesting a previously unappreciated pathway for cholesterol transport. We show dynamic membrane contacts between peroxisome and lysosome, which are mediated by lysosomal Synaptotagmin VII binding to the lipid PI(4,5)P2 on peroxisomal membrane. LDL-cholesterol enhances such contacts, and cholesterol is transported from lysosome to peroxisome. Disruption of critical peroxisome genes leads to cholesterol accumulation in lysosome. Together, these findings reveal an unexpected role of peroxisome in intracellular cholesterol transport. We further demonstrate massive cholesterol accumulation in human patient cells and mouse model of peroxisomal disorders, suggesting a contribution of abnormal cholesterol accumulation to these diseases.

Identification of an arthropod molecular target for plant-derived natural repellents.

Arthropods maintain ecosystem balance while also contributing to the spread of disease. Plant-derived natural repellents represent an ecological method of pest control, but their direct molecular targets in arthropods remain to be further elucidated. Occupying a critical phylogenetic niche in arthropod evolution, scorpions retain an ancestral genetic profile. Here, using a behavior-guided screening of the Mesobuthus martensii genome, we identified a scorpion transient receptor potential (sTRP1) channel that senses Cymbopogon-derived natural repellents, while remaining insensitive to the synthetic chemical pesticide DEET. Scrutinizing orthologs of sTRP1 in Drosophila melanogaster, we further demonstrated dTRPγ ion channel as a chemosensory receptor of natural repellents to mediate avoidance behavior. This study sheds light on arthropod molecular targets of natural repellents, exemplifying the arthropod­plant adaptation. It should also help the rational design of insect control strategy and in conserving biodiversity.

Genome-wide association study and genomic selection of spike-related traits in bread wheat.

KEY MESSAGE: Identification of 337 stable MTAs for wheat spike-related traits improved model accuracy, and favorable alleles of MTA259 and MTA64 increased grain weight and yield per plant. Wheat (Triticum aestivum L.) is one of the three primary global, staple crops. Improving spike-related traits in wheat is crucial for optimizing spike and plant morphology, ultimately leading to increased grain yield. Here, we performed a genome-wide association study using a dataset of 24,889 high-quality unique single-nucleotide polymorphisms (SNPs) and phenotypic data from 314 wheat accessions across eight diverse environments. In total, 337 stable and significant marker-trait associations (MTAs) related to spike-related traits were identified. MTA259 and MTA64 were consistently detected in seven and six environments, respectively. The presence of favorable alleles associated with MTA259 and MTA64 significantly reduced wheat spike exsertion length and spike length, while enhancing thousand kernel weight and yield per plant. Combined gene expression and network analyses identified TraesCS6D03G0692300 and TraesCS6D03G0692700 as candidate genes for MTA259 and TraesCS2D03G0111700 and TraesCS2D03G0112500 for MTA64. The identified MTAs significantly improved the prediction accuracy of each model compared with using all the SNPs, and the random forest model was optimal for genome selection. Additionally, the eight stable and major MTAs, including MTA259, MTA64, MTA66, MTA94, MTA110, MTA165, MTA180, and MTA164, were converted into cost-effective and efficient detection markers. This study provided valuable genetic resources and reliable molecular markers for wheat breeding programs.

The industrial solvent 1,4-dioxane causes hyperalgesia by targeting capsaicin receptor TRPV1.

BACKGROUND: The synthetic chemical 1,4-dioxane is used as industrial solvent, food, and care product additive. 1,4-Dioxane has been noted to influence the nervous system in long-term animal experiments and in humans, but the molecular mechanisms underlying its effects on animals were not previously known. RESULTS: Here, we report that 1,4-dioxane potentiates the capsaicin-sensitive transient receptor potential (TRP) channel TRPV1, thereby causing hyperalgesia in mouse model. This effect was abolished by CRISPR/Cas9-mediated genetic deletion of TRPV1 in sensory neurons, but enhanced under inflammatory conditions. 1,4-Dioxane lowered the temperature threshold for TRPV1 thermal activation and potentiated the channel sensitivity to agonistic stimuli. 1,3-dioxane and tetrahydrofuran which are structurally related to 1,4-dioxane also potentiated TRPV1 activation. The residue M572 in the S4-S5 linker region of TRPV1 was found to be crucial for direct activation of the channel by 1,4-dioxane and its analogs. A single residue mutation M572V abrogated the 1,4-dioxane-evoked currents while largely preserving the capsaicin responses. Our results further demonstrate that this residue exerts a gating effect through hydrophobic interactions and support the existence of discrete domains for multimodal gating of TRPV1 channel. CONCLUSIONS: Our results suggest TRPV1 is a co-receptor for 1,4-dioxane and that this accounts for its ability to dysregulate body nociceptive sensation.

The Kv1.3 ion channel acts as a host factor restricting viral entry.

Virus entry into cells is the initial stage of infection and involves multiple steps, and interfering viral entry represents potential antiviral approaches. Ion channels are pore-forming membrane proteins controlling cellular ion homeostasis and regulating many physiological processes, but their roles during viral infection have rarely been explored. Here, the functional Kv1.3 ion channel was found to be expressed in human hepatic cells and tissues. The Kv1.3 was then revealed to restrict HCV entry via inhibiting endosome acidification-mediated viral membrane fusion. The Kv1.3 was also demonstrated to inhibit DENV and ZIKV with an endosome acidification-dependent entry, but have no effect on SeV with a neutral pH penetration. A Kv1.3 antagonist PAP-1 treatment accelerated animal death in ZIKV-infected Ifnar1-/- mice. Moreover, Kv1.3-deletion was found to promote weight loss and reduce survival rate in ZIKV-infected Kv1.3-/- mice. Altogether, the Kv1.3 ion channel behaves as a host factor restricting viral entry. These findings broaden understanding about ion channel biology.

Association between smoking and postoperative delirium in surgical patients with pulmonary hypertension: a secondary analysis of a cohort study.

BACKGROUND: Previous studies have declared that smoking was a risk factor for postoperative delirium (POD), but others have inconsistent results. Up till now, the association between smoking and POD has not been verified. This study investigates the relationship between smoking and POD in patients with pulmonary hypertension (PHTN) in the United States. METHODS: Patients with PHTN who underwent non-cardiac, non-obstetric surgery were enrolled in the original research completed by Aalap C. et al. We further excluded the patients undergoing intracranial surgery and the patients with sepsis and perioperative stroke to avoid interference with POD assessment. The generalized linear model and generalized additive model were used to explore the relationship between smoking and POD. The propensity score adjustment was used for sensitivity analyses. RESULTS: Five hundred thirty-nine patients were included in this study. The overall incidence of POD was 3.0% (16/539). After adjusting the potential confounders (age, systemic hypertension, coronary artery disease, COPD, length of surgery, intrathoracic surgery, vascular surgery), a positive relationship was found between smoking status and POD (OR = 4.53, 95% CI: 1.22 to 16.86, P = 0.0243). In addition, the curvilinear relationship between smoking burden (pack-years) and POD is close to a linear relationship. CONCLUSION: Smoking probably shows a positive correlation with POD in patients with PHTN.

Recovery from tachyphylaxis of TRPV1 coincides with recycling to the surface membrane.

The transient receptor potential vanilloid-1 (TRPV1) ion channel is essential for sensation of thermal and chemical pain. TRPV1 activation is accompanied by Ca2+-dependent desensitization; acute desensitization reflects rapid reduction in channel activity during stimulation, whereas tachyphylaxis denotes the diminution in TRPV1 responses to repetitive stimulation. Acute desensitization has been attributed to conformational changes of the TRPV1 channel; however, the mechanisms underlying the establishment of tachyphylaxis remain to be defined. Here, we report that the degree of whole-cell TRPV1 tachyphylaxis is regulated by the strength of inducing stimulation. Using light-sheet microscopy and pH-sensitive sensor pHluorin to follow TRPV1 endocytosis and exocytosis trafficking, we provide real-time information that tachyphylaxis of different degrees concurs with TRPV1 recycling to the plasma membrane in a proportional manner. This process controls TRPV1 surface expression level thereby the whole-cell nociceptive response. We further show that activity-gated TRPV1 trafficking associates with intracellular Ca2+ signals of distinct kinetics, and recruits recycling routes mediated by synaptotagmin 1 and 7, respectively. These results suggest that activity-dependent TRPV1 recycling contributes to the establishment of tachyphylaxis.

Initial recovery of fish faunas following the implementation of pen-culture and fishing bans in floodplain lakes along the Yangtze River.

Given the decline of natural fish abundance and diversity, a ban on pen-culture and fishing has been imposed on floodplain lakes along the Yangtze River. In order to examine the recovery efficiency of fish faunas, we compared the changes in multidimensional (α and ß) diversity in the Shengjin Lake between pen-culture stage (PS) and recovery stage (RS). Our results demonstrated significant variations in fish community composition, with distinct populational restoration in wild species of high trophic level and river-lake migratory species. The higher abundance of wild and migratory species in RS implied the enhanced dispersal and exchange process of fish individuals with the elimination of net pens. Despite significant variations of community composition, the α and ß diversity indices exhibited non-significant change between PS and RS. However, our study still revealed the recovery of natural seasonal community dynamics, since there were significant variations of both α and ß diversity between high-water (HW) and low-water (LW) seasons in RS. The significant higher α diversity (S, d, H') in HW indicated flooding induced fish supplements in floodplain lakes, due to the well-developed breeding sites, nurseries and refuges provided by floodplain lakes. Meanwhile, the significant lower ßSOR and ßSIM in HW implied the homogenized communities during flooding seasons, which can be ascribed to better hydrological connectivity of various habitats and more even distribution of fish faunas triggered by flood pulses. The reappearance of natural seasonal variations in multidimensional (α and ß) diversity indicate the initial recovery of fish faunas. There is a pressing need for prolonged surveillance to explore the recovery mechanism of fish assemblage. Meanwhile, our results also highlight the importance of conserving the lacustrine connectivity and seasonal flooding for the recovery of fishery resources in the floodplain lakes.

Site-specific contacts enable distinct modes of TRPV1 regulation by the potassium channel Kvß1 subunit.

Transient receptor potential vanilloid 1 (TRPV1) channel is a multimodal receptor that is responsible for nociceptive, thermal, and mechanical sensations. However, which biomolecular partners specifically interact with TRPV1 remains to be elucidated. Here, we used cDNA library screening of genes from mouse dorsal root ganglia combined with patch-clamp electrophysiology to identify the voltage-gated potassium channel auxiliary subunit Kvß1 physically interacting with TRPV1 channel and regulating its function. The interaction was validated in situ using endogenous dorsal root ganglia neurons, as well as a recombinant expression model in HEK 293T cells. The presence of Kvß1 enhanced the expression stability of TRPV1 channels on the plasma membrane and the nociceptive current density. Surprisingly, Kvß1 interaction also shifted the temperature threshold for TRPV1 thermal activation. Using site-specific mapping, we further revealed that Kvß1 interacted with the membrane-distal domain and membrane-proximal domain of TRPV1 to regulate its membrane expression and temperature-activation threshold, respectively. Our data therefore suggest that Kvß1 is a key element in the TRPV1 signaling complex and exerts dual regulatory effects in a site-specific manner.

Genetic characterization of a new NSP2-deletion porcine reproductive and Respiratory Syndrome Virus in China.

The Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) cause a huge economic loss around the pig industry worldwide; the NADC30-like PRRSV have attracted much attention outbreaks in China in recent years. Recombination between PRRSV subtypes, point mutations, insertions and deletions that contribute to the emergence of new variants in the genome. In this study, the PRRSV-HB-16-China-2019 strain's full-length genomic sequence shares 93.0% nucleotide similarity to NADC30 PRRSV without any gene insertion. Compared with VR-2332, it has an NSP2 coding region that is different from NADC30, which has a discontinuous 206-aa (111-aa from position 323 to 433 and 95-aa from position 476 to 570) deletion. Compared with other NADC30-Like strains, it has a discontinuous 75-amino acid (75-aa from position 476 to 552) deletion, which was first reported. Notably, the strain, PRRSV-HB-16-China-2019, contained an addition a 1-aa deletion in ORF5 and a unique 3-nt deletion in 3'-UTR similar to NADC30, the strain is recombined between a NADC30-like strain and a vaccine strain named RespPRRS MLV(parental strain VR-2332). Our findings indicate that PRRSV-HB-16-China-2019 is a new NSP2-deletion NADC30-like strain with certain deletions and mutations. Our results show that the emergence of the new NADC30-like strain has increased the difficulty of PRRSV prevention in China.

Aldosterone enhances high phosphate-induced vascular calcification through inhibition of AMPK-mediated autophagy.

It remains unclear whether the necessity of calcified mellitus induced by high inorganic phosphate (Pi) is required and the roles of autophagy plays in aldosterone (Aldo)-enhanced vascular calcification (VC) and vascular smooth muscle cell (VSMC) osteogenic differentiation. In the present study, we found that Aldo enhanced VC both in vivo and in vitro only in the presence of high Pi, alongside with increased expression of VSMC osteogenic proteins (BMP2, Runx2 and OCN) and decreased expression of VSMC contractile proteins (α-SMA, SM22α and smoothelin). However, these effects were blocked by mineralocorticoid receptor inhibitor, spironolactone. In addition, the stimulatory effects of Aldo on VSMC calcification were further accelerated by the autophagy inhibitor, 3-MA, and were counteracted by the autophagy inducer, rapamycin. Moreover, inhibiting adenosine monophosphate-activated protein kinase (AMPK) by Compound C attenuated Aldo/MR-enhanced VC. These results suggested that Aldo facilitates high Pi-induced VSMC osteogenic phenotypic switch and calcification through MR-mediated signalling pathways that involve AMPK-dependent autophagy, which provided new insights into Aldo excess-associated VC in various settings.

Proposed a self-absorption internal standard model to detect element concentrations of complex constituent material with a single emission line of element in laser plasmas.

Laser induced plasmas (LIPs) method is a highly regarded approach to evaluate the chemical composition of materials. But the strong self-absorption of the radiation seriously affects its accuracy. Meanwhile, the model based on self-absorption phenomenon makes its application very difficult. In this work, a self-absorption internal standard (SAIS) model is proposed for detection of the multi-element concentrations of complex constituent material with a single emission line of the element in laser plasmas. A typical LIPs experiment system is set up to generate plasmas, and the soil is selected as a test sample. The average electron temperature (0.975 eV) and electron density (1.44×1018 cm-3) are determined by the Boltzmann plot and emission lines Stark broadening, respectively. The plasmas are diagnosed as in local thermodynamic equilibrium condition. The emission lines selected to calculate the concentration of sample contain a wide set of kt values (0.575×10-30∼37.2×10-30 m3). Then, the concentrations of some elements are calculated by the model using single emission line of each element. It is found that the concentrations of the five elements (Ti, Fe, Mg, Al, Si) calculated by SAIS model are relatively consistent with the results of the traditional chemical testing methods. This indicated that the SAIS model is an effective and neat method for multi-element concentrations detection of complex constituent materials.

The role and clinical significance of programmed cell death- ligand 1 expressed on CD19+B-cells and subsets in systemic lupus erythematosus.

BACKGROUND: Programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1)-targeted therapies have enhanced T-cell response and demonstrated efficacy in the treatment of multiple cancers. However, the role and clinical significance of PD-L1 expression on CD19+ B-cells and their subsets, with particular reference to systemic lupus erythematosus (SLE), have not yet been studied in detail. OBJECTIVE: The present study aimed to investigate PD-L1 expression on CD19+ B-cells and their subsets, in addition to exploring its possible role in Tfh-cell activation and B-cell differentiation in SLE. METHODS: Frequencies of CD19+ B-cells, their subsets, PD-L1 and Tfh cells in the peripheral blood of SLE patients and healthy controls (HCs) were determined using cytometry. The clinical data of SLE patients were recorded in detail, and the correlation between their laboratory parameters, clinical parameters and disease activity indices was statistically analyzed. CD19+PD-L1+B-cells and CD19+PD-L1- B-cells were sorted and cultured with a stimulant, following which the supernatants were collected for immunoglobulin G and anti-double stranded DNA detection via enzyme-linked immunosorbent assay. RESULTS: In SLE patients, CD19+B-cells and partial subgroups were enriched in peripheral blood. Also, the observed increase in the frequency of CD19+PD-L1+B-cells was significantly associated with a higher disease activity index. An in vitro culture test demonstrated that the amounts of anti-dsDNA and immunoglobulin G secreted by the CD19+PD-L1+B-cells of SLE patients and HCs were vastly different. In addition, a strong correlation existed between the frequencies of CD19+PD-L1+B-cells and defined Tfh cells of SLE patients. CONCLUSION: This study demonstrated that the expression of CD19+PD-L1+B-cells in the peripheral blood of SLE patients was abnormal, and that disease-related laboratory parameters and clinical indicators were correlated. CD19+PD-L1+B-cells were enriched and played a critical role in activating the pathogenic T-cell and B-cell responses in patients with SLE.

Unidirectional complexation of pillar[4]arene[1]benzoquinoneoxime with alkyl alcohols.

Despite progress in the unidirectional complexation of cyclodextrins and calixarenes with nonsymmetric guests, unidirectional complexation using pillararenes as hosts remains scarcely explored. In this report, we describe the formation of unidirectional [2]pseudorotaxane-like complexes which were realized using n-alkyl alcohol guests and pillar[4]arene[1]benzoquinoneoxime made from pillar[4]arene[1]quinone in a selective monofunctionalizing manner.

Molecular identification of BrHAB2a, one of the two AtHAB2-like proteins in Brassica rapa, is an important component of ABA signaling.

Abscisic acid (ABA) signaling is a vital physiological step that is used by many land plants to fight against environmental stress. As components of the linear ABA signaling pathway, clade A protein phosphatases type 2C (PP2C-As) are mainly inhibited by PYRABACTIN RESISTANCE1/PYR1-LIKE/REGULATORY COMPONENTS OF ABA RECEPTORS (PYLs)-type receptors upon their binding to ABA. Here, we show that the genome of Brassica rapa encodes 14 putative clade A PP2C-like proteins (BrPP2C-As). Two of these BrPP2C-As, Bra025964 and Bra016595, show high similarity to the HAB2 (Homology to ABI2) protein in Arabidopsis. RNAseq data reveal that nearly all BrPP2C-As, like BrHAB2a (Bra025964) and BrHAB2b (Bra016595), were highly expressed in at least one tissue. Overexpression of BrHAB2a conferred ABA insensitivity to Arabidopsis thaliana seedlings. Furthermore, the phosphatase activity of BrHAB2a could be inhibited by AtPYL1 or BrPYL1 in the presence of ABA. Overall, these results suggest that BrHAB2a is a functional PP2C-A like protein phosphotase and a key component of ABA signaling in Brassica rapa.

Molecular detection and genomic characterization of porcine circovirus 3 in pigs from Northeast China.

BACKGROUND: First identified in the United States in 2016, porcine circovirus type 3 (PCV3) is a newly emerging porcine circovirus exhibiting a wide range of clinical syndromes, which may be associated with the pathogenicity observed in pigs. RESULTS: The aim of this study was to identify and characterize the full genome sequence of PCV3 strains circulating in Northeast China. Herein, 105 lung samples isolated from sick pigs in Northeast China during 2018 were analyzed for PCV3. Using PCR, the total PCV3-positive rate was 33.3% (35/105), with rates of 17.8% (8/45), 66.7% (10/15), and 37.8% (17/45) in Heilongjiang, Jilin, and Liaoning province, respectively. Additionally, our findings showed that PCV3-positive samples had a high rate of co-infection with PCV2, PPV6, and PPV7. To study the evolution of the PCV3 in Northeast China, we sequenced the entire genome of 13 strains of PCV3. The results of phylogenetic analyses revealed that PCV3 could be divided into two clades, PCV3a and PCV3b. Interestingly, a G deletion at position 1072 was found in the 1999 nt genome of PCV3-CN2018LN-4 (MH277118). The G deletion terminated replicase protein translation and induced a truncated replicase protein. CONCLUSION: These results contribute to the understanding of PCV3 molecular epidemiology and evolution in Northeast China. A new strain of PCV3 with truncated replicase protein was identified.

[The Study of Protective Effect of Paeoniflorin on Lung Injury in MRL/lpr Mice].

OBJECTIVE: To investigate the protective effects of paeoniflorin on the lung injury in systemic lupus erythematosus with mouse model. METHODS: Ten wild type mice and 40 MRL/lpr mice were used in this study. MRL/lpr mice were randomly assigned to MRL/lpr group,MRL/lpr + dexamethasone (1.5 mg/kg) group,MRL/lpr + paeoniflorin (20 mg/kg) group,and MRL/lpr + paeoniflorin (40 mg/kg). The levels of malondialdehyde (MDA) , superoxide dismutase (SOD) ,catalase (CAT) ,glutathione peroxidase (GSH-Px) in serum were detected. The serum levesl of inflammatory cytokines were measured. Lung pathological changes were determined by HE staining. The protein level of phospho-phosphatidylinositol-3 kinase (P-PI3K),phospho-serine-threonine kinase B(P-Akt) ,phospho-nuclear factor kappa B (P-NF-κB),phospho-inhibitor of nuclear factor kappa Bα (P-IκBα) were detected by Western blot. RESULTS: Paeoniflorin decreased serum level of MDA and increased the levels of SOD,CAT,GSH-PX,and decreased the levels of inflammatory cytokines. Paeoniflorin improved lung pathological changes and inhibited the protein levels of P-PI3K,P-Akt,P-NF-κBp65,and P-IκBα in the lung tissue of MRL/lpr mice. CONCLUSION: Paeoniflorin may be beneficial for the prevention of lung injury in systemic lupus erythematosus.

AAV9-NPC1 significantly ameliorates Purkinje cell death and behavioral abnormalities in mouse NPC disease.

Niemann-Pick type C (NPC) disease is a fatal inherited neurodegenerative disorder caused by loss-of-function mutations in the NPC1 or NPC2 gene. There is no effective way to treat NPC disease. In this study, we used adeno-associated virus (AAV) serotype 9 (AAV9) to deliver a functional NPC1 gene systemically into NPC1-/- mice at postnatal day 4. One single AAV9-NPC1 injection resulted in robust NPC1 expression in various tissues, including brain, heart, and lung. Strikingly, AAV9-mediated NPC1 delivery significantly promoted Purkinje cell survival, restored locomotor activity and coordination, and increased the lifespan of NPC1-/- mice. Our work suggests that AAV-based gene therapy is a promising means to treat NPC disease.

Molecular characterization of an AtPYL1-like protein, BrPYL1, as a putative ABA receptor in Brassica rapa.

Abscisic acid (ABA)-induced physiological changes are conserved in many land plants and underlie their responses to environmental stress and pathogens. The PYRABACTIN RESISTANCE1/PYR1-LIKE/REGULATORY COMPONENTS OF ABA RECEPTORS (PYLs)-type receptors perceive the ABA signal and initiate signal transduction. Here, we show that the genome of Brassica rapa encodes 24 putative AtPYL-like proteins. The AtPYL-like proteins in Brassica rapa (BrPYLs) can also be classified into 3 subclasses. We found that nearly all BrPYLs displayed high expression in at least one tissue. Overexpression of BrPYL1 conferred ABA hypersensitivity to Arabidopsis. Further, ABA activated the expression of an ABA-responsive reporter in Arabidopsis protoplasts expressing BrPYL1. Overall, these results suggest that BrPYL1 is a putative functional ABA receptor in Brassica rapa.