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Background: Erythromycin A (Er A) has a broad antibacterial effect and is a source of erythromycin derivatives. Methylation of erythromycin C (Er C), catalyzed by S-adenosyl-methionine (SAM)-dependent O-methyltransferase EryG, is the key final step in Er A biosynthesis. Er A biosynthesis, including EryG production, is regulated by the phosphate response factor PhoP and the nitrogen response factor GlnR. However, the regulatory effect of these proteins upon S-adenosyl-methionine synthetase (MetK) production is unknown., Results: In this study, we used bioinformatics approaches to identify metK (SACE_3900), which codes for S-adenosyl-methionine synthetase (MetK). Electrophoretic mobility shift assays (EMSAs) revealed that PhoP and GlnR directly interact with the promoter of metK, and quantitative PCR (RT-qPCR) confirmed that each protein positively regulated metK transcription. Moreover, intracellular SAM was increased upon overexpression of either phoP or glnR under phosphate or nitrogen limited conditions, respectively. Finally, both the production of Er A and the transformation ratio from Er C to Er A increased upon phoP overexpression, but surprisingly, not upon glnR overexpression., Conclusions: Manipulating the phosphate and nitrogen response factors, PhoP and GlnR provides a novel strategy for increasing the yield of SAM and the production of Er A in Saccharopolyspora erythraea ., (© 2022. The Author(s).)

The dataset presents the raw data collected through an online survey of senior high school students and their parents from 24 provinces, municipalities and autonomous regions (96 cities) of China. We conducted the online survey using electronic self-administered questionnaires designed as student-version and parent-version during 26th February and 4th March of 2020. The questionnaires were designed using the online survey tool Sojump (Shanghai Information Co.), and released through WeChat platform (Tencent Corp) following principals-head teachers-students/parents approach. All the students and the parents were asked to answer the questions voluntarily and anonymously after reading informed consent at the fore page of the questionnaires. The information collected from students included: 1) demographic characteristics, including sex, date of birth, name of high school, academic year, and self-evaluated performance level; 2) educational levels and occupations of parents; 3) degree preferences, including the willingness to learn medicine (prior and post COVID-19 outbreak), preferred medical career (clinician, public health practitioner, pharmacist, nurse or others), and main motivations for selecting or unselecting medical study; 4) infection of COVID-19 in acquaintances; 5) health literacy level on infectious diseases assessed using the Infectious Disease-specific Health Literacy Scale (IDSHL), and 6) anxiety level evaluated using the Chinese version of the Generalized Anxiety Disorder Screener (GAD-7). Information collected from parents included sex of their children and name of high school attended by their children, as well as their own educational level, occupation, anxiety symptoms, attitude toward their children's studying medicine, and main reasons for supportive or unsupportive attitudes, which were similar to the main motivations or de-motivations for medical study listed in the student-version questionnaire. Date and time for completion of the questionnaire were auto-recorded by the Sojump system. The dataset was established at the early stage of pandemic of COVID-19, and is valuable for understanding the instant psychological impacts of the outbreak of an emerging fatal infectious disease on senior high school students and their patents, and can provide evidence for policymakers on mental health intervention and medical education in China. The data are provided with this article., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s). Published by Elsevier Inc.)

Cellular senescence (CS), a state of permanent growth arrest, is intertwined with tumorigenesis. Due to the absence of specific markers, characterizing senescence levels and senescence-related phenotypes across cancer types remain unexplored. Here, we defined computational metrics of senescence levels as CS scores to delineate CS landscape across 33 cancer types and 29 normal tissues and explored CS-associated phenotypes by integrating multiplatform data from ~20 000 patients and ~212 000 single-cell profiles. CS scores showed cancer type-specific associations with genomic and immune characteristics and significantly predicted immunotherapy responses and patient prognosis in multiple cancers. Single-cell CS quantification revealed intra-tumor heterogeneity and activated immune microenvironment in senescent prostate cancer. Using machine learning algorithms, we identified three CS genes as potential prognostic predictors in prostate cancer and verified them by immunohistochemical assays in 72 patients. Our study provides a comprehensive framework for evaluating senescence levels and clinical relevance, gaining insights into CS roles in cancer- and senescence-related biomarker discovery., (© The Author(s) 2022. Published by Oxford University Press.)

Background: The outbreak of COVID-19 has been a big challenge for senior high school students in China who are facing tremendous pressure of the highly competitive College Entrance Examination., Methods: To evaluate the psychological impact of the event in the population, we conducted an anonymous online survey among senior high school students in China between 26 Feb and 4 March, 2020. Information collected included demographic characteristics, attitude toward medical study, infection of COVID-19 in acquaintances, anxiety symptoms evaluated using the GAD-7, and health literacy level measured using the IDSHL., Results: Of 21,085 participants, 3,575 (17.0%), 943 (4.5%) and 448 (2.1%) reported with mild, moderate, and severe anxiety. Female, higher academic year, worse self-evaluated academic performance, negative attitude toward medical study, living in Hubei province and having acquaintance infected with COVID-19 were significantly associated with anxiety level, while higher education level of mother and higher IDSHL score were associated with a lower risk. The score of IDSHL, particularly of the domain "infectious disease prevention", was associated with the GAD-7 score in a linear pattern (β=-0.0371, p<0.01)., Limitations: Limitations included the cross-sectional study design unable to infer the casual relationship, anonymous survey, selection bias and self-reported anxiety disorder levels., Conclusions: The results suggested that COVID-19 outbreak may increase anxiety level in senior high school students in China. The anxiety related factors observed in this study may help to identify vulnerable individuals and develop interventions., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Mycobacterium tuberculosis is a global human pathogen that infects macrophages and can establish a latent infection. Emerging evidence has established the nutrients metabolism as a key point to study the pathogenesis of M. tuberculosis and host immunity. It was reported that fatty acids and cholesterol are the major nutrient sources of M. tuberculosis in the period of infection. However, the mechanism by which M. tuberculosis utilizes lipids for maintaining life activities in nutrient-deficiency macrophages is poorly understood. Mycobacterium smegmatis is fast-growing and generally used to study its pathogenic counterpart, M. tuberculosis . In this work, we found that the phosphate sensing regulator RegX3 of M. smegmatis is required for its growing on propionate and surviving in macrophages. We further demonstrated that the expression of prpR and related genes ( prpDBC ) in methylcitrate cycle could be enhanced by RegX3 in response to the phosphate-starvation condition. The binding sites of the promoter region of prpR for RegX3 and PrpR were investigated. In addition, cell morphology assay showed that RegX3 is responsible for cell morphological elongation, thus promoting the proliferation and survival of M. smegmatis in macrophages. Taken together, our findings revealed a novel transcriptional regulation mechanism of RegX3 on propionate metabolism, and uncovered that the nutrients-sensing regulatory system puts bacteria at metabolic steady state by altering cell morphology. More importantly, since we observed that M. tuberculosis RegX3 also binds to the prpR operon in vitro , the RegX3-mediated regulation might be general in M. tuberculosis and other mycobacteria for nutrient sensing and environmental adaptation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Pei, Qi, Li, Wo and Ye.)

The senescence and degeneration of the intervertebral disc are closely related to the reduction of nucleus pulposus (NP) cells caused by apoptosis. TIR-domain-containing adapter-inducing interferon-β (TRIF) is an adapter for Toll-like receptors 3/4 (TLR3/4), which involves in cell apoptosis. The aim of this study is to detect the role of TRIF in the apoptotic progress of NP cells. The expression of collagen II, aggrecan, TLR3/4, and TRIF were analyzed in different degrees of degenerated human NP samples from patients. NP cells were isolated from mild degenerated tissues and cultured with IL-1β to accelerate the degradation, and treated with TLR3/4 protein. siRNA was used to silence TRIF gene expression, and TRLF-plasmid was used to upregulate TRLF gene expression. We used flow cytometry assay to analyze cell apoptosis. The expression of collagen II, aggrecan, TLF3/4, TRIF, caspase-8/3, MMP-13, TNF-α was determined by immunofluorescence, Western blot, or RT-PCR. That the expression of collagen II and aggrecan markedly decreased, but TLF3/4, TRIF, caspase-8/3, MMP-3, TNF-α, and IL-1β were increased in severely degenerated disc tissues. IL-1β treatment induced NP cell degeneration and TLF3/4, TRIF, caspase-8/3, MMP-3, TNF-α overexpression. TLF3/4 protein treatment promoted NP cell degeneration and apoptosis by upregulation of TRIF, caspase-8/3, MMP-3, and TNF-α. Furthermore, TRIF silencing reversed the negative effect of TLF3/4 overexpression, and TRIF overexpression played the same role in NP cell apoptosis. Based on these results, we believe that TRIF is activated in a degenerated intervertebral disc. TLF3/4 promotes NP cell apoptosis and inflammation through the TRLF adaptor. TRLF expression is positively related to the apoptosis and inflammation in NP cells. These results suggest a therapeutic potential of the TRIF in the treatment of disc degeneration., (Copyright 2020 Biolife Sas. www.biolifesas.org.)

Redox balance, an essential feature of healthy physiological steady states, is regulated by circadian clocks, but whether or how endogenous redox signalling conversely regulates clockworks in mammals remains unknown. Here, we report circadian rhythms in the levels of endogenous H 2 O 2 in mammalian cells and mouse livers. Using an unbiased method to screen for H 2 O 2 -sensitive transcription factors, we discovered that rhythmic redox control of CLOCK directly by endogenous H 2 O 2 oscillations is required for proper intracellular clock function. Importantly, perturbations in the rhythm of H 2 O 2 levels induced by the loss of p66 Shc , which oscillates rhythmically in the liver and suprachiasmatic nucleus (SCN) of mice, disturb the rhythmic redox control of CLOCK function, reprogram hepatic transcriptome oscillations, lengthen the circadian period in mice and modulate light-induced clock resetting. Our findings suggest that redox signalling rhythms are intrinsically coupled to the circadian system through reversible oxidative modification of CLOCK and constitute essential mechanistic timekeeping components in mammals.

Both caloric restriction (CR) and mitochondrial proteostasis are linked to longevity, but how CR maintains mitochondrial proteostasis in mammals remains elusive. MicroRNAs (miRNAs) are well known for gene silencing in cytoplasm and have recently been identified in mitochondria, but knowledge regarding their influence on mitochondrial function is limited. Here, we report that CR increases miRNAs, which are required for the CR-induced activation of mitochondrial translation, in mouse liver. The ablation of miR-122, the most abundant miRNA induced by CR, or the retardation of miRNA biogenesis via Drosha knockdown significantly reduces the CR-induced activation of mitochondrial translation. Importantly, CR-induced miRNAs cause the overproduction of mtDNA-encoded proteins, which induces the mitochondrial unfolded protein response (UPR mt ), and consequently improves mitochondrial proteostasis and function. These findings establish a physiological role of miRNA-enhanced mitochondrial function during CR and reveal miRNAs as critical mediators of CR in inducing UPR mt to improve mitochondrial proteostasis., (Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.)

Owing to the spread of multidrug resistance (MDR) and extensive drug resistance (XDR), there is a pressing need to identify potential targets for the development of more-effective anti-M. tuberculosis (Mtb) drugs. PafA, as the sole Prokaryotic Ubiquitin-like Protein ligase in the Pup-proteasome System (PPS) of Mtb, is an attractive drug target. Here, we show that the activity of purified Mtb PafA is significantly inhibited upon the association of AEBSF (4-(2-aminoethyl) benzenesulfonyl fluoride) to PafA residue Serine 119 (S119). Mutation of S119 to amino acids that resemble AEBSF has similar inhibitory effects on the activity of purified Mtb PafA. Structural analysis reveals that although S119 is distant from the PafA catalytic site, it is located at a critical position in the groove where PafA binds the C-terminal region of Pup. Phenotypic studies demonstrate that S119 plays critical roles in the function of Mtb PafA when tested in M. smegmatis. Our study suggests that targeting S119 is a promising direction for developing an inhibitor of M. tuberculosis PafA., (Copyright © 2018 German Center for Neurodegenerative Diseases (DZNE). Published by Elsevier B.V. All rights reserved.)

Objective: Abdominal aortic aneurysm (AAA) is a life-threatening vascular pathology, the pathogenesis of which is closely related to oxidative stress. However, an effective pharmaceutical treatment is lacking because the exact cause of AAA remains unknown. Here, we aimed at delineating the role of the paraoxonases (PONs) gene cluster (PC), which prevents atherosclerosis through the detoxification of oxidized substrates, in AAA formation., Approach and Results: PC transgenic (Tg) mice were crossed to an Apoe -/- background, and an angiotensin II-induced AAA mouse model was used to analyze the effect of the PC on AAA formation. Four weeks after angiotensin II infusion, PC-Tg Apoe -/- mice had a lower AAA incidence, smaller maximal abdominal aortic external diameter, and less medial elastin degradation than Apoe -/- mice. Importantly, PC-Tg Apoe -/- mice exhibited lower aortic reactive oxidative species production and oxidative stress than did the Apoe -/- control mice. As a consequence, the PC transgene alleviated angiotensin II-induced arterial inflammation and suppressed arterial extracellular matrix degradation. Specifically, on angiotensin II stimulation, PC-Tg vascular smooth muscle cells exhibited lower levels of reactive oxidative species production and a decrease in the activities and expression levels of matrix metalloproteinase-2 and matrix metalloproteinase-9. Moreover, PC-Tg serum also enhanced vascular smooth muscle cell oxidative stress resistance and further decreased the expression levels of matrix metalloproteinase-2 and matrix metalloproteinase-9, indicating that circulatory and vascular smooth muscle cell PC members suppress oxidative stress in a synergistic manner., Conclusions: Our findings reveal, for the first time, a protective role of the PC in AAA formation and suggest PONs as promising targets for AAA prevention., (© 2016 American Heart Association, Inc.)

Cardiac hypertrophy is the strongest predictor of the development of heart failure, and anti-hypertrophic treatment holds the key to improving the clinical syndrome and increasing the survival rates for heart failure. The paraoxonase (PON) gene cluster (PC) protects against atherosclerosis and coronary artery diseases. However, the role of PC in the heart is largely unknown. To evaluate the roles of PC in cardiac hypertrophy, transgenic mice carrying the intact human PON1, PON2, and PON3 genes and their flanking sequences were studied. We demonstrated that the PC transgene (PC-Tg) protected mice from cardiac hypertrophy induced by Ang II; these mice had reduced heart weight/body weight ratios, decreased left ventricular wall thicknesses and increased fractional shortening compared with wild-type (WT) control. The same protective tendency was also observed with an Apoe -/- background. Mechanically, PC-Tg normalized the disequilibrium of matrix metalloproteinases (MMPs)/tissue inhibitors of MMPs (TIMPs) in hypertrophic hearts, which might contribute to the protective role of PC-Tg in cardiac fibrosis and, thus, protect against cardiac remodeling. Taken together, our results identify a novel anti-hypertrophic role for the PON gene cluster, suggesting a possible strategy for the treatment of cardiac hypertrophy through elevating the levels of the PON gene family.

Rationale: Uncontrolled growth of abdominal aortic aneurysms (AAAs) is a life-threatening vascular disease without an effective pharmaceutical treatment. AAA incidence dramatically increases with advancing age in men. However, the molecular mechanisms by which aging predisposes individuals to AAAs remain unknown., Objective: In this study, we investigated the role of SIRT1 (Sirtuin 1), a class III histone deacetylase, in AAA formation and the underlying mechanisms linking vascular senescence and inflammation., Methods and Results: The expression and activity of SIRT1 were significantly decreased in human AAA samples. SIRT1 in vascular smooth muscle cells was remarkably downregulated in the suprarenal aortas of aged mice, in which AAAs induced by angiotensin II infusion were significantly elevated. Moreover, vascular smooth muscle cell-specific knockout of SIRT1 accelerated angiotensin II-induced formation and rupture of AAAs and AAA-related pathological changes, whereas vascular smooth muscle cell-specific overexpression of SIRT1 suppressed angiotensin II-induced AAA formation and progression in Apoe - /- mice. Furthermore, the inhibitory effect of SIRT1 on AAA formation was also proved in a calcium chloride (CaCl 2 )-induced AAA model. Mechanistically, the reduction of SIRT1 was shown to increase vascular cell senescence and upregulate p21 expression, as well as enhance vascular inflammation. Notably, inhibition of p21-dependent vascular cell senescence by SIRT1 blocked angiotensin II-induced nuclear factor-κB binding on the promoter of monocyte chemoattractant protein-1 and inhibited its expression., Conclusions: These findings provide evidence that SIRT1 reduction links vascular senescence and inflammation to AAAs and that SIRT1 in vascular smooth muscle cells provides a therapeutic target for the prevention of AAA formation., (© 2016 American Heart Association, Inc.)

Mitral valve-related operations are easy to perform and show good results, but to prevent severe thromboembolism or a high ratio of prosthetic valve destruction by tissue, lifetime anticoagulant therapy is essential after the operation. Thus, identifying a new type of surgical procedure and prosthetic valve to cure mitral valve diseases is necessary. Pulmonary valve autograft transplantation (Ross II) with the "top hat" transplantation technique was first reported by Ross DN to cure mitral disease. Because the "top hat" procedure has some shortcomings, we designed the scaffold-pulmonary autograft transplantation procedure and performed animal experiments to confirm the feasibility and effectiveness of the procedure. A total of 13 minipigs, weighing 20-25 kg, were employed as experimental animals to undergo scaffold-pulmonary autograft valve transplantation in our surgical animal lab. The surgical procedure was performed under hypothermic general anaesthesia and extracorporeal circulation (or cardiopulmonary bypass, CPB). Briefly, the chest cave was opened through the left intercostal, the pulmonary valve autograft was harvested during on-pump beating heart, and the pulmonary valve autograft was mounted in a self-made pulmonary valve scaffold and transferred to the mitral valve annulus without removing the mitral instruments. Finally, the outflow tract of the right ventricle was re-established with a pig pulmonary homograft. After finishing data collection, all animals were executed 1 hour after removal from the CPB. For the 13 minipigs that underwent the operation, the CPB time was 182.4 ± 23.4 min. Two of the thirteen cases died of bleeding during the operation and of a post-operative pulmonary embolism, and the remaining eleven survived for one hour. The pressure of the left atrium did not increase significantly (P = 1.00), and the ultrasonic cardiograph (UCG) showed good function of the new mitral valves, with mean ejection fraction (EF) values of 63.6%. The mitral valve orifice areas were 1.10 ± 0.13 cm(2) (pre-operation) and 1.01 ± 0.08 cm(2) (post-operation) (P = 0.013). The function and structure of the new mitral valves were normal. We preliminarily consider scaffold-pulmonary autograft valve transplantation to be a new alternative to cure mitral valve disease, but advanced chronic animal experiments will be needed to confirm the long-term results of the operation. The results showed it could be a new alternative to cure mitral valve disease.

A number of widely diverse compounds that show inhibitory activities at the picrotoxinin binding sites in housefly and rat GABA receptors were investigated by using the distance comparison technique (DISCOtech) and comparative molecular field analysis (CoMFA) methods to explore the pharmacophore models and the three-dimensional quantitative structure-activity relationships (3D-QSAR) of the compounds. These compounds consist of three diverse types of noncompetitive GABA receptor antagonists, i.e., trioxabicyclooctanes and their derivatives, picrodendrins and related terpenoids, and fipronil and its analogs. For investigation of the structural requirements for inhibitory activity at the picrotoxinin binding site of GABA receptor, DISCOtech pharmacophore models containing one center of hydrophobic ring and two hydrogen bond acceptor atoms for both housefly-head and rat-brain GABA receptors were constructed, respectively. In particular, the interacting areas in housefly receptors appear to be wider than that in rat receptors, the differences between rat and housefly receptor models implicate the selectivity of noncompetitive GABA receptor antagonists. In addition, corresponding CoMFA models with good statistical indices (r(2)>0.9 and q(2)>0.5) were also obtained. These models can be used as guidance for the development of new compounds with high activities and selectivities.

The ubiquitin-proteasome pathway plays a crucial role in the regulation of many physiological processes and in the development of a number of major human diseases, such as cancer, Alzheimer's, Parkinson's, diabetes, etc. As a new target, the study on the proteasome inhibitors has received much attention recently. Three-dimensional quantitative structure-activity relationship (3D-QSAR) studies using comparative molecule field analysis (CoMFA) and comparative molecule similarity indices analysis (CoMSIA) techniques were applied to analyze the binding affinity of a set of tripeptide aldehyde inhibitors of 20S proteasome. The optimal CoMFA and CoMSIA models obtained for the training set were all statistically significant with cross-validated coefficients (q(2)) of 0.615, 0.591 and conventional coefficients (r(2)) of 0.901, 0.894, respectively. These models were validated by a test set of eight molecules that were not included in the training set. The predicted correlation coefficients (r(2)) of CoMFA and CoMSIA are 0.944 and 0.861, respectively. The CoMFA and CoMSIA field contour maps agree well with the structural characteristics of the binding pocket of beta5 subunit of 20S proteasome, which suggests that the 3D-QSAR models built in this paper can be used to guide the development of novel inhibitors of 20S proteasome.

Objective: To summarize the clinical experience of Ross procedure in treatment of aorta valve diseases., Methods: The clinical data of 15 patients with aorta valve diseases, 12 men and 3 women, aged 30 +/- 14, including 13 cases of congenital aorta valve disease, 1 case of senile degenerative aortic valve disease, and 1 case of subacte bacterial endocarditis complicated by aortic stenosis (AS), with the heart function (NYHA) of class II in 11 cases and class III in 4 cases, underwent Ross procedure from October 1994 to September 2002 in Anzhen Hospital. Before operation, ultrasound cardiography showed moderate to severe AS and/or aortic insufficiency (AI) with an average aortic valve annulus diameter (AVD) of 2.4 +/- 0.4 cm and normal pulmonary valve. Operation was performed on all patients under cardiopulmonary bypass and moderate hypothermia. The operation procedure was as follows: (1) to take off the auto-pulmonary artery valve; (2) to remove the dysfunctional aortic valve and auto-transplant the pulmonary valve on the aortic root; and (3) to put a pulmonary homograft so as to re-establish on the right ventricular outflow tract., Results: The perieoperative mortality is 0. After the operation, the mean pressure gradient of aortic valve was in the normal limitation (7.23 +/- 0.14 mm Hg), the left ventricular diastolic diameter decreased significantly (P < 0.001), the left ventricular ejection fraction was 0.48 +/- 0.22, and the heart function (NYHA) was at the classes I - II in all the patients. All cases received follow-up of 1 - 9 years, their heart function was all in Class I, and the function of their aortic and pulmonary valves remained well., Conclusion: Ross procedure is a kind of effective alterative operation in treating patients with aortic valve disease.