VDAC1 balances mitophagy and apoptosis in leafhopper upon arbovirus infection.

Mitophagy is a form of autophagy that selectively removes damaged mitochondria and attenuates mitochondrial-dependent apoptosis during viral infection, but how arboviruses balance mitophagy and apoptosis to facilitate persistent viral infection in insect vectors without causing evident fitness cost remains elusive. Here, we identified mitochondrial VDAC1 (voltage-dependent anion channel 1) that could be hijacked by nonstructural protein Pns11 of rice gall dwarf virus (RGDV), a plant nonenveloped double-stranded RNA virus, to synergistically activate pro-viral extensive mitophagy and limited apoptosis in leafhopper vectors. The direct target of fibrillar structures constructed by Pns11 with VDAC1 induced mitochondrial degeneration. Moreover, the degenerated mitochondria were recruited into Pns11-induced phagophores to initiate mitophagy via interaction of VDAC1 with Pns11 and an autophagy protein, ATG8. Such mitophagy mediated by Pns11 and VDAC1 required the classical PRKN/Parkin-PINK1 pathway. VDAC1 regulates apoptosis by controlling the release of apoptotic signaling molecules through its pore, while the anti-apoptotic protein GSN (gelsolin) could bind to VDAC1 pore. We demonstrated that the interaction of Pns11 with VDAC1 and gelsolin decreased VDAC1 expression but increased GSN expression, which prevented the extensive apoptotic response in virus-infected regions. Meanwhile, virus-induced mitophagy also effectively prevented extensive apoptotic response to decrease apoptosis-caused insect fitness cost. The subsequent fusion of virus-loaded mitophagosomes with lysosomes is prevented, and thus such mitophagosomes are exploited for persistent spread of virions within insect bodies. Our results reveal a new strategy for arboviruses to balance and exploit mitophagy and apoptosis, resulting in an optimal intracellular environment for persistent viral propagation in insect vectors.Abbreviations: ATG: autophagy related; BNIP3: BCL2 interacting protein 3; CYCS/CytC: cytochrome c, somatic; dsGSN: double-stranded RNAs targeting GSN/gelsolin; dsGFP: double-stranded RNAs targeting green fluorescent protein; dsPRKN: double-stranded RNAs targeting PRKN; dsPns11: double-stranded RNAs targeting Pns11; dsRNA: double-stranded RNA; EC: epithelia cell; GST: glutathione S-transferase; LAMP1: lysosomal associated membrane protein 1; Mito: mitochondrion; Mmg: middle midgut; MP, mitophagosome; PG, phagophore. padp: post-first access to diseased plants; PINK1: PTEN induced kinase 1; RGDV: rice gall dwarf virus; SQSTM1: sequestosome 1; TOMM20: translocase of outer mitochondrial membrane 20; TUNEL: terminal deoxynucleotidyl transferase dUTP nick end labeling; VDAC1: voltage dependent anion channel 1.

GAPDH mediates plant reovirus-induced incomplete autophagy for persistent viral infection in leafhopper vector.

Macroautophagy/autophagy is a conserved mechanism launched by host organisms to fight against virus infection. Double-membraned autophagosomes in arthropod vectors can be remodeled by arboviruses to accommodate virions and facilitate persistent viral propagation, but the underlying mechanism is unknown. Rice gall dwarf virus (RGDV), a plant nonenveloped double-stranded RNA virus, induces the formation of virus-containing double-membraned autophagosomes to benefit persistent viral propagation in leafhopper vectors. In this study, it was found that the capsid protein P2 of RGDV alone induced autophagy. P2 specifically interacted with GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and ATG4B both in vitro and in vivo. Furthermore, the GAPDH-ATG4B complex could be recruited to virus-induced autophagosomes. Silencing of GAPDH or ATG4B expression suppressed ATG8 lipidation, autophagosome formation, and efficient viral propagation. Thus, P2 could directly recruit the GAPDH-ATG4B complex to induce the formation of initial autophagosomes. Furthermore, such autophagosomes were modified to evade fusion with lysosomes for degradation, and thus could be persistently exploited by viruses to facilitate efficient propagation. GAPDH bound to ATG14 and inhibited the interaction of ATG14 with SNAP29, thereby preventing ATG14-SNARE proteins from mediating autophagosome-lysosome fusion. Taken together, these results highlight how RGDV activates GAPDH to initiate autophagosome formation and block autophagosome degradation, finally facilitating persistent viral propagation in insect vectors. The findings reveal a positive regulation of immune response in insect vectors during viral infection.

Insights into the interaction of cyclooxygenase and lipoxygenase with natural compound 3,4',5,7-Tetrahydroxyflavone based on multi-spectroscopic and metabolomics.

Hypoxia induce right ventricular dysfunction in human heart, but the molecular mechanism remains limited. As known, cyclooxygenases (COX) and lipoxygenases (LOX) play a key role in the cardiovascular system under hypoxia. 3,4',5,7-Tetrahydroxyflavone (THF), which widely exists in a variety of plants and vegetables, is famous for good ability to relieve cardiac injury, but the mechanism remains to be further understood. In this study, we firstly estimated the preventive role of THF against hypoxia-induced right ventricular dysfunction. Metabolomics analysis showed there were differential metabolites involved in above process, which helped us to screen the crucial regulated enzymes of these metabolites. Molecular docking and multi-spectroscopic revealed the molecular mechanism of interaction between THF and COX/LOX. Results suggested that THF bound to COX/LOX through static quenching and these bindings were driven by hydrogen bonds. After binding with THF, the secondary structure of COX/LOX was changed. In general, this study indicated that THF inhibited COX/LOX by spontaneously forming complexes with them.

Targeted metabolomics combined with network pharmacology to reveal the protective role of luteolin in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a progressive disease that significantly endangers human health, where metabolism may drive pathogenesis: a shift from mitochondrial oxidation to glycolysis occurs in diseased pulmonary vessels and the right ventricle. An increase in pulmonary vascular resistance in patients with heart failure with a preserved ejection fraction portends a poor prognosis. Luteolin exists in numerous foods and is marketed as a dietary supplement assisting in many disease treatments. However, little is known about the protective effect of luteolin on metabolism disorders in diseased pulmonary vessels. In this study, we found that luteolin apparently reversed the pulmonary vascular remodeling of PAH rats by inhibiting the abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs). Moreover, network pharmacology and metabolomics results revealed that the arachidonic acid pathway, amino acid pathway and TCA cycle were dysregulated in PAH. A total of 14 differential metabolites were significantly changed during the PAH, including DHA, PGE2, PGD2, LTB4, 12-HETE, 15-HETE, PGF2α, and 8-iso-PGF2α metabolites in the arachidonic acid pathway, and L-asparagine, oxaloacetate, N-acetyl-L-ornithine, butane diacid, ornithine, glutamic acid metabolites in amino acid and TCA pathways. However, treatment with luteolin recovered the LTB4, PGE2, PGD2, 12-HETE, 15-HETE, PGF2α and 8-iso-PGF2α levels close to normal. Meanwhile, we showed that luteolin also downregulated the gene and protein levels of COX 1, 5-LOX, 12-LOX, and 15-LOX in the arachidonic acid pathway. Collectively, this work highlighted the metabolic mechanism of luteolin-protected PAH and showed that luteolin would hold great potential in PAH prevention.

Increasing obstructive sleep apnea risk is associated with hearing impairment in middle-aged Chinese men-A cross-sectional study.

OBJECTIVE: Midlife males with obstructive sleep apnea (OSA) bear a high risk for cardiovascular diseases. However, the association of OSA and hearing impairment is controversial. Our objective was to observe the incidence of hearing loss in middle-aged males with different risks for OSA. METHODS: 794 men aged 40-65 who participated in health examination and pure tone hearing screening between January and June 2021 were recruited in the study. Medical history was collected. Height, weight and blood pressure were tested, and biochemical test including blood lipids and blood glucose was performed. According to the STOP-BANG score, the observed subjects were divided into low, intermediate and high groups for OSA risk. Hearing impairment was defined as failure in responding to any pure tone of 25 dB HL in any ear at the frequencies: 4 kHz for high frequency range and 0.5k, 1k, 2 kHz for low/medium frequency range. The incidence of hearing loss in those groups was compared after adjusting the cardiovascular risk factors. RESULTS: The incidence of hearing impairment in the groups of intermediate, high, and intermediate/high risk for OSA (46.9%, 45.2%, 46.3%, respectively) were higher than that in the group of low risk for OSA (33.3%, P<0.001). After adjusting cardiovascular risk factors, the risk of hearing impairment in the group of high risk for OSA is 1.64 times of the group of low risk for OSA (95%CI: 1.02-2.69, P<0.05). The risk of hearing impairment at high frequency(4kHz) in the group of intermediate/high risk for OSA is 1.43 times of the group of low-risk for OSA (95%CI: 1.00-2.06, P<0.05). CONCLUSION: The risk of hearing impairment in midlife men with high, intermediate/high risk for OSA is significantly increased, especially at high frequency of 4 kHz.

Integrated metabolomics and mechanism to reveal the protective effect of kaempferol on pulmonary arterial hypertension.

Currently, there have been breakthroughs in the study of the underlying mechanisms of pulmonary arterial hypertension, but treatment is still challenging. The aim of this study was explore the effect of kaempferol in PAH and discover the mechanism of this process. First, we assessed the effect of kaempferol in animal models of PAH. The echocardiography and pressure-volume admittance catheter data showed that kaempferol could improve right ventricular function and alleviate the progression of PAH. Moreover, morphometric analysis of the lung vasculature indicated that pulmonary vascular remodeling could be reduced by kaempferol. The expression of autophagy-related proteins and autophagic processes were evaluated by western blotting and mRFP-GFP-LC3 fluorescence microscopy, the results indicated that autophagy played an important role in the process by which kaempferol prevents PAH. Moreover, we performed untargeted and targeted plasma metabolomics analysis on rat models of PAH and used multivariate analysis to reveal multiple pathways and targets. Consequently, we identified 247 plasma biomarkers that were tightly linked to the preventive effects of kaempferol, which were mainly related to amino acid metabolism and arachidonic acid metabolism. In conclusion, kaempferol could effectively alleviate the development of PAH by regulating abnormal autophagy and metabolic disorders, providing a novel perspective on the treatment of PAH.

Exosomes mediate horizontal transmission of viral pathogens from insect vectors to plant phloem.

Numerous piercing-sucking insects can horizontally transmit viral pathogens together with saliva to plant phloem, but the mechanism remains elusive. Here, we report that an important rice reovirus has hijacked small vesicles, referred to as exosomes, to traverse the apical plasmalemma into saliva-stored cavities in the salivary glands of leafhopper vectors. Thus, virions were horizontally transmitted with exosomes into rice phloem to establish the initial plant infection during vector feeding. The purified exosomes secreted from cultured leafhopper cells were enriched with virions. Silencing the exosomal secretion-related small GTPase Rab27a or treatment with the exosomal biogenesis inhibitor GW4869 strongly prevented viral exosomal release in vivo and in vitro. Furthermore, the specific interaction of the 15-nm-long domain of the viral outer capsid protein with Rab5 induced the packaging of virions in exosomes, ultimately activating the Rab27a-dependent exosomal release pathway. We thus anticipate that exosome-mediated viral horizontal transmission is the conserved strategy hijacked by vector-borne viruses.

Microstructure analysis and mechanical properties of phosphorus-reinforced ZCuPb20Sn5 alloy.

An investigation was carried out to assess the effect of the P content on the microstructure and mechanical properties of ZCuPb20Sn5 alloy. Alloys of various compositions, (0.05, 0.1, 0.2, 0.3, 0.5% wt.% P) were melted in a melting furnace under 1200 °C and cast into metal mould, the hardness, strength and elongation of alloy castings which adding P or not in melting process were tested and the casting mircostructure was analyzed. The results show that the second phase appeared and gradually increased in amount with the content of P elements increased. Also, the microstructure of ZCuPb20Sn5 alloy was refined, and the average size of lead inclusions was reduced and formed a dispersed network of eutectoid inclusions.The addition of P had a beneficial effect on the microstructure and properties of ZCuPb20Sn5 alloy. The hardness and tensile strength of ZCuPb20Sn5 alloy increased, but the elongation increased at first, then decreased, when the P content increased. When the P content was less than 0.1 wt.%, the functions of phosphorous copper mainly was used as a deoxidizing initial gas, but when exceeded 0.1 wt.%, a second phase reinforcing particle formed with copper or nickel together, which improved the mechanical properties of the alloy. However, the elongation was lowered due to the brittle phosphide phase.

Prevalence and associated factors of diabetic retinopathy in Beijing, China: a cross-sectional study.

OBJECTIVES: The study aimed to determine the exact risk factors for diabetic retinopathy (DR) in the Chinese population using a cohort of 17 985 individuals from Beijing, China. DESIGN: Cross-sectional study. SETTING: A hospital. PARTICIPANTS: 17 985 individuals from Beijing, China. PRIMARY AND SECONDARY OUTCOME MEASURES: This was a cross-sectional study of permanent residents from the Changping area (Beijing, China) recruited from July 2010 to March 2011 and from March 2014 to February 2015 during a routine health examination at the Tongren Hospital of Beijing. Eye examinations were conducted by experienced ophthalmologists. Medical history, height, weight, body mass index (BMI) and blood pressure were recorded. Routine laboratory examinations were performed. RESULTS: The prevalence of DR was 1.5% in the general study population and 8.1% among individuals with diabetes. Compared with the non-DR group, individuals in the DR group in the diabetes population had longer disease duration, higher systolic blood pressure (SBP), fasting plasma glucose (FPG) and uric acid (UA) (in men) and lower UA (in women) (all p<0.05). The multivariate analysis showed that disease duration (p<0.001), BMI (p=0.046), SBP (p=0.012), creatinine clearance rate (CCR) (p=0.014), UA (p=0.018) and FPG (p<0.001) were independently associated with DR in patients with diabetes. CONCLUSION: The prevalence of DR was 8.1% among patients with diabetes. Disease duration, BMI, SBP, CCR, UA and FPG were independently associated with DR.