Objective:To construct bacterial cytoplasmic membrane nanovesicles(BMV)with overexpressing programmed death 1(PD-1),denoted as BMV-PD-1 and evaluate the targeting efficacy of BMV-PD-1 towards transplanted lung tumor tissues in mice.Methods:The fusion plasmid ClyA-PD-1-EGFP fused by PD-1 and Cytolysin A(ClyA)was transferred into Escherichia coli BL21-Codonplus through plasmid transformation.Laser confocal microscopy,SDS-PAGE,and WB were used to detect the expression of the fusion protein ClyA-PD-1-EGFP.Bacterial membranes were extracted and processed with an extruder to generate BMV-PD-1.TEM and NTA were utilized to assess the morphology,size distribution,and zeta potential of BMV-PD-1,while WB was used to verify the presence of PD-1 protein.Laser confocal imaging was conducted to monitor the uptake of BMV-PD-1 by Lewis lung cancer cells.A C57BL/6J mouse subcutaneous transplant tumor model of LLC lung cancer cells was constructed,and the tumor targeting of BMV-PD-1 was evaluated by small animal imaging system.Results:Laser confocal microscopy images demonstrated that the plasmid ClyA-PD-1-EGFP was transferred into BL21-Codonplus and successfully expressed into protein.SDS-PAGE results suggested that ClyA-PD-1-EGFP was overexpressed in BL21-Codonplus.WB analysis indicated that PD-1 was expressed in bacteria and highly expressed in BMV-PD-1(P<0.001).NTA and TEM analyses revealed that BMV-PD-1 were spherical vesicles with a diameter of(145±14)nm and a negative surface charge.Laser confocal imaging showed that the high expression of PD-1 significantly increased the uptake of BMV-PD-1 by lung cancer cells(P<0.01).In vivo imaging of small animals further confirmed that the high expression of PD-1 can effectively improve cancer targeting of BMV-PD-1(P<0.01).Conclusion:In this study,bacterial plasma membrane nanovesicles BMV-PD-1 with high PD-1 expression are successfully constructed,and it is found that PD-1 overexpression markedly improve the mouse lung cancer xenograft tissue targeting specificity of BMV-PD-1,laying the groundwork for further development of BMV-PD-1 as a carrier for targeted drug delivery systems in tumors.

Objective:To explore the impact of sleep duration, physical exercise, and their interactions on the risk of dyslipidemia in older adults aged ≥80 (the oldest old) in China.Methods:The study subjects were the oldest old from four rounds of Healthy Aging and Biomarkers Cohort Study (2008-2009, 2011-2012, 2014 and 2017-2018). The information about their demographic characteristics, lifestyles, physical examination results and others were collected, and fasting venous blood samples were collected from them for blood lipid testing. Competing risk model was used to analyze the causal associations of sleep duration and physical exercise with the risk for dyslipidemia. Restricted cubic spline (RCS) function was used to explore the dose-response relationship between sleep duration and the risk for dyslipidemia. Additive and multiplicative interaction model were used to explore the interaction of sleep duration and physical exercise on the risk for dyslipidemia.Results:The average age of 1 809 subjects was (93.1±7.7) years, 65.1% of them were women. The average sleep duration of the subjects was (8.0±2.5) hours/day, 28.1% of them had sleep duration for less than 7 hours/day, and 27.2% had sleep for duration more than 9 hours/day at baseline survey. During the 9-year cumulative follow-up of 6 150.6 person years (follow-up of average 3.4 years for one person), there were 304 new cases of dyslipidemia, with an incidence density of 4 942.6/100 000 person years. The results of competitive risk model analysis showed that compared with those who slept for 7-9 hours/day, the risk for dyslipidemia in oldest old with sleep duration >9 hours/day increased by 22% ( HR=1.22, 95% CI: 1.07-1.39). Compared with the oldest old having no physical exercise, the risk for dyslipidemia in the oldest old having physical exercise decreased by 33% ( HR=0.67, 95% CI: 0.57-0.78). The RCS function showed a linear positive dose-response relationship between sleep duration and the risk for hyperlipidemia. The interaction analysis showed that physical exercise and sleep duration had an antagonistic effect on the risk for hyperlipidemia. Conclusion:Physical exercise could reduce the adverse effects of prolonged sleep on blood lipids in the oldest old.

Parkinson’s disease (PD) is the second most common neurodegenerative disease, which manifests with both motor and non-motor symptoms. Circadian rhythm dysregulation, as one of the most challenging non-motor features of PD, usually appears long before obvious motor symptoms. Moreover, the dysregulated circadian rhythm has recently been reported to play pivotal roles in PD pathogenesis, and it has emerged as a hot topic in PD research. In this review, we briefly introduce the circadian rhythm and circadian rhythm-related genes, and then summarize recent research progress on the altered circadian rhythm in PD, ranging from clinical features to the possible causes of PD-related circadian disorders. We believe that future comprehensive studies on the topic may not only help us to explore the mechanisms of PD, but also shed light on the better management of PD.

Despite the high mutation rate of HIV-1, the amino acid sequences of the membrane-spanning domain (MSD) of HIV-1 gp41 are well conserved. Arginine residues are rarely found in single membrane-spanning domains, yet an arginine residue, R(696) (the numbering is based on that of HXB2), is highly conserved in HIV-1 gp41. To examine the role of R(696), it was mutated to K, A, I, L, D, E, N, and Q. Most of these substitutions did not affect the expression, processing or surface distribution of the envelope protein (Env). However, a syncytia formation assay showed that the substitution of R(696) with amino acid residues other than K, a naturally observed mutation in the gp41 MSD, decreased fusion activity. Substitution with hydrophobic amino acid residues (A, I, and L) resulted in a modest decrease, while substitution with D or E, potentially negatively-charged residues, almost abolished the syncytia formation. All the fusion-defective mutants showed slower kinetics with the cell-based dual split protein (DSP) assay that scores the degree of membrane fusion based on pore formation between fusing cells. Interestingly, the D and E substitutions did show some fusion activity in the DSP assays, suggesting that proteins containing D or E substitutions retained some fusion pore-forming capability. However, nascent pores failed to develop, due probably to impaired activity in the pore enlargement process. Our data show the importance of this conserved arginine residue for efficient membrane fusion.
Amino Acid Substitution ; Animals ; Arginine ; chemistry ; metabolism ; Cell Line ; Cercopithecus aethiops ; HIV Envelope Protein gp41 ; chemistry ; metabolism ; HIV-1 ; metabolism ; Humans ; Kinetics ; Membrane Fusion ; physiology ; Mutation ; Protein Structure, Tertiary

Objective To study the effects of 50 Hz low voltage electric stimulation on angiogenesis and the expression of VEGF in the ischemic myoeardium in rats. Methods Twelve Wistar rats with experimentally induced myocardial ischemia were randomly divided into an electric stimulation (ES) group and a control group. The animals in the electric stimulation group were electrically stimulated at 50 Hz and 0.3 V through electrodes implanted in the epicardium of the anterior wall of the left artrium. Those in the control group were delivered sham electrical stimula- tion through similar implanted electrodes. Immunohistochemistry was used to count endothelial cells (ECs) and measure the capillary density (CD). A reverse transcription polymerase chain reaction (RT-PCR) was employed to measure the expression of VEGF protein and VEGF mRNA. Results The number of ECs, and the CDs in the ES group were significantly greater than in the control group, and the expression of VEGF protein and VEGF mRNA was also significantly higher. Conclusions Low voltage electrical stimulation at 50 Hz can promote angiogenesis and the expression of VEGF in the ischemic myocardium in rats.