Mapping turnover of dissolved organic carbon in global topsoil

Dissolved organic carbon (DOC), the labile fraction of organic carbon, is a predominant substrate for microbes. Therefore, the turnover of DOC dominates microbial respiration in soils. We compiled a global dataset (1096 data points) of the turnover rates of DOC in 0-30 cm soil profiles and integrated the data with a machine learning algorithm to develop a global map of DOC turnover rate in global topsoil. The global DOC turnover rate in 0-30 cm soil was averaged as 0.0087 day-1, with a considerable variation among biomes. The fastest DOC turnover rate was found in tropical forests (0.0175 day-1) and the lowest in tundra (0.0036 day-1), exhibiting a declining trend from low to high latitudes. The DOC turnover rate is primarily controlled by edaphic and climate factors, as confirmed by the analyses with the structural equation model and the Mental's test. With a machine learning algorithm, we produced global maps of DOC turnover rate at a monthly scale, which were further combined with a global dataset of DOC density to produce monthly maps of carbon mineralization from DOC turnover in topsoil. The annual carbon release from DOC was estimated as 27.98 Pg C year-1 from topsoil across the globe, with the largest contribution from forest biomes, followed by pasture and grassland. Tundra released the least carbon from DOC due to its low turnover rate suppressed by low temperatures. The biome- and global-scale information of DOC turnover rate and carbon release from DOC provide a benchmark for ecosystem models to better project soil carbon dynamics and their contributions to global carbon cycling in the changing environment.

Warming-induced vapor pressure deficit suppression of vegetation growth diminished in northern peatlands

Recent studies have reported worldwide vegetation suppression in response to increasing atmospheric vapor pressure deficit (VPD). Here, we integrate multisource datasets to show that increasing VPD caused by warming alone does not suppress vegetation growth in northern peatlands. A site-level manipulation experiment and a multiple-site synthesis find a neutral impact of rising VPD on vegetation growth; regional analysis manifests a strong declining gradient of VPD suppression impacts from sparsely distributed peatland to densely distributed peatland. The major mechanism adopted by plants in response to rising VPD is the "open" water-use strategy, where stomatal regulation is relaxed to maximize carbon uptake. These unique surface characteristics evolve in the wet soil‒air environment in the northern peatlands. The neutral VPD impacts observed in northern peatlands contrast with the vegetation suppression reported in global nonpeatland areas under rising VPD caused by concurrent warming and decreasing relative humidity, suggesting model improvement for representing VPD impacts in northern peatlands remains necessary.

[Safety and efficacy of transcatheter aortic valve replacement using the "All in One" single artery/vessel technique]

Objective: To explore the safety and efficacy of transcatheter aortic valve replacement (TAVR) using the "All in One" single-artery/vessel technique. Methods: This is a retrospective study. A total of 30 consecutive patients underwent TAVR using the single artery/vascular technique in Beijing Anzhen Hospital from August to December 2021 were included. Baseline clinical data, operative situation, postoperative outcomes, and incidence of adverse events during hospitalization and at one month post TAVR were analyzed. Results: Mean age was (72.6±9.7) years, 16 were male patients, STS score was (4.73±3.12)%. Four patients were diagnosed as isolated aortic regurgitation (all with tricuspid aortic valves), and 26 patients were diagnosed as aortic stenosis (AS), 10 of whom with tricuspid aortic valves and 16 of whom with bicuspid aortic valves. The single-vessel technique was applied in 3 aortic stenosis cases; the single-artery technique was applied in 27 cases. Echocardiography was performed immediately after procedure and results showed no or trace perivalvular leak in 27 cases and small perivalvular leak in 3 cases; the mean aortic transvalvular gradient of 26 AS patients decreased from (50.4±16.0) mmHg (1 mmHg=0.133 kPa) to (9.4±3.2) mmHg (P<0.001). The procedure time was (64.8±18.9) min. There were no intraoperative death, valve displacement, conversion to surgery, coronary artery occlusion in all 30 patients. There were no major cardiac adverse events such as myocardial infarction or stroke occurred during hospitalization or at follow-up. One-month follow-up echocardiography indicated prosthesis works well. The symptoms were significantly alleviated, and the Kansas City Cardiomyopathy Score (KCCQ score) of all patients increased from 48.1±18.4 to 73.5±17.6 (P<0.001). Conclusions: TAVR using the single artery/vessel technique is safe and feasible. This technique is related to reduced access complications and worthy of wide application.

[Feasibility study of using bridging temporary permanent pacemaker in patients with high-degree atrioventricular block after TAVR]

Objective: To determine the feasibility of using temporary permanent pacemaker (TPPM) in patients with high-degree atrioventricular block (AVB) after transcatheter aortic valve replacement (TAVR) as bridging strategy to reduce avoidable permanent pacemaker implantation. Methods: This is a prospective observational study. Consecutive patients undergoing TAVR at Beijing Anzhen Hospital and the First Affiliated Hospital of Zhengzhou University from August 2021 to February 2022 were screened. Patients with high-degree AVB and TPPM were included. Patients were followed up for 4 weeks with pacemaker interrogation at every week. The endpoint was the success rate of TPPM removal and free from permanent pacemaker at 1 month after TPPM. The criteria of removing TPPM was no indication of permanent pacing and no pacing signal in 12 lead electrocardiogram (EGG) and 24 hours dynamic EGG, meanwhile the last pacemaker interrogation indicated that ventricular pacing rate was 0. Routinely follow-up ECG was extended to 6 months after removal of TPPM. Results: Ten patients met the inclusion criteria for TPPM, aged (77.0±11.1) years, wirh 7 females. There were 7 patients with third-degree AVB, 1 patient with second-degree AVB, 2 patients with first degree AVB with PR interval>240 ms and LBBB with QRS duration>150 ms. TPPM were applied on the 10 patients for (35±7) days. Among 8 patients with high-degree AVB, 3 recovered to sinus rhythm, and 3 recovered to sinus rhythm with bundle branch block. The other 2 patients with persistent third-degree AVB received permanent pacemaker implantation. For the 2 patients with first-degree AVB and LBBB, PR interval shortened to within 200 ms. TPPM was successfully removed in 8 patients (8/10) at 1 month without permanent pacemaker implantation, of which 2 patients recovered within 24 hours after TAVR and 6 patients recovered 24 hours later after TAVR. No aggravation of conduction block or permanent pacemaker indication were observed in 8 patients during follow-up at 6 months. No procedure-related adverse events occurred in all patients. Conclusion: TPPM is reliable and safe to provide certain buffer time to distinguish whether a permanent pacemaker is necessary in patients with high-degree conduction block after TAVR.

Environmental stress stimulates microbial activities as indicated by cyclopropane fatty acid enhancement

Soil microbial responses to environmental stress remain a critical question in microbial ecology. The content of cyclopropane fatty acid (CFA) in cytomembrane has been widely used to evaluate environmental stress on microorganisms. Here, we used CFA to investigate the ecological suitability of microbial communities and found a stimulating impact of CFA on microbial activities during wetland reclamation in Sanjiang Plain, Northeastern China. The seasonality of environmental stress resulted in the fluctuation of CFA content in the soil, which suppressed microbial activities due to nutrient loss upon wetland reclamation. After land conversion, the aggravation of temperature stress to microbes increased the CFA content by 5 % (autumn) to 163 % (winter), which led to the suppression of microbial activities by 7 %-47 %. By contrast, the warmer soil temperature and permeability decreased the CFA content by 3 % to 41 % and consequently aggravated the microbial reduction by 15 %-72 % in spring and summer. Complex microbial communities of 1300 CFA-produced species were identified using a sequencing approach, suggesting that soil nutrients dominated the differentiation in these microbial community structures. Further analysis with structural equation modeling highlighted the important function of CFA content to environmental stress and the stimulating influence of CFA induced by environmental stress on microbial activities. Our study shows the biological mechanisms of seasonal CFA content for microbial adaption to environmental stress under wetland reclamation. It advances our knowledge of microbial physiology affecting soil element cycling caused by anthropogenic activities.

[Legal regulation of clinical application of artificial intelligence]

With the wide application of artificial intelligence (AI) technology in clinical practice, more and more legal problems need to be solved. At present, although the legal status of AI is still controversial in academic and practical circles, its infringement risk in clinical diagnosis and surgery cannot be avoided. On the basis of the distinction between strong and weak AI liability subjects, those who meet the requirements of infringement, damage consequence, causal relationship, subjective fault, etc., can constitute tort liability, but the existence of exemption causes can also exempt liability. In addition to the ex post accountability of tort liability, it is also necessary to establish a complete administrative legal regulation system. At present, China needs to explore and establish the classification registration system, compulsory insurance system and reserve system of AI as soon as possible, so as to strengthen the legal regulation of the whole process of AI clinical application before, during and after the event.

Comparison of automated breast volume scanning with conventional ultrasonography, mammography, and MRI to assess residual breast cancer after neoadjuvant therapy by molecular type

AIM

To compare the accuracy of hand-held ultrasonography (US), mammography (MG), magnetic resonance imaging (MRI), and automated breast volume scanning (ABVS) in defining residual breast cancer tumour size after neoadjuvant therapy (NAT).

MATERIALS AND METHODS

Patients diagnosed breast cancer and who received NAT at the Breast Center, Peking University People's Hospital, were enrolled prospectively. Imaging was performed after the last cycle of NAT. The residual tumour size, intraclass correlation coefficients (ICCs), and receiver operating characteristic (ROC) to predict pathological complete response (pCR) were analysed.

RESULTS

A total of 156 patients with 159 tumours were analysed. ABVS had a moderate correlation with histopathology residual tumour size (ICC = 0.666), and showed high agreement among triple-positive tumours (ICC = 0.797). With 5 mm as the threshold, the coincidence rate reached 64.7% between ABVS and pathological size, which was significantly higher than that between US, MG, MRI, and pathological size (50%, 45.1%, 41.4%; p=0.009, p=0.001, p<0.001, respectively). For ROC analysis, ABVS demonstrated a higher area under the ROC curve, but with no statistical difference, except for MG (0.855, 0.816, 0.819, and 0.788, respectively; p=0.183 for US, p=0.044 for MG, and p=0.397 for MRI, with ABVS as the reference).

CONCLUSIONS

The longest tumour diameter on ABVS had a moderate correlation with pathological residual invasive tumour size. ABVS was shown to have good ability to predict pCR and would appear to be a potential useful tool for the assessment after NAT for breast cancer.

Metagenomic evidence of suppressed methanogenic pathways along soil profile after wetland conversion to cropland

Wetland conversion to cropland substantially suppresses methane (CH4) emissions due to the strong suppression of methanogenesis, which consists of various pathways. In this study, we evaluated the cultivation impacts on four predominant CH4 production pathways, including acetate, carbon dioxide (CO2), methylamines, and methanol, in a wetland and cultivated cropland in northeastern China. The results showed significant suppression of CH4 production potential and the abundance of genes for all four methanogenic pathways in cropland. The consistency between CH4 production and methanogenesis genes indicates the robustness of genomic genes in analyzing methanogenesis. The suppression effects varied across seasons and along soil profiles, most evident in spring and 0 to 30 cm layers. The acetate pathway accounted for 55% in wetland vs. 70% in the cropland of all functional genes for CH4 production; while the other three pathways were stronger in response to cultivation, which presented as stronger suppressions in both abundance of functional genes (declines are 52% of CO2 pathway, 68% of methanol pathway, and 62% of methylamines pathway, vs. 19% of acetate pathway) and their percentages in four pathways (from 20 to 15% for CO2, 15 to 9% for methylamines, and 10 to 6% for methanol pathway vs. 55 to 70% for acetate pathway). The structural equation models showed that substrate availability was most correlated with CH4 production potential in the wetland, while the positive correlations of acetate, CO2, and methylamine pathways with CH4 production potential were significant in the cropland. The quantitative responses of four CH4 production pathways to land conversion reported in this study provide benchmark information for validating the CH4 model in simulating CH4 cycling under land use and land cover change.

[Sacubitril/valsartan attenuates left ventricular remodeling and improve cardiac function by upregulating apelin/APJ pathway in rats with heart failure]

Objective: To investigate the effect and mechanism of sacubitril/valsartan on left ventricular remodeling and cardiac function in rats with heart failure. Methods: A total of 46 SPF-grade male Wistar rats weighed 300-350 g were acclimatized to the laboratory for 7 days. Rats were then divided into 4 groups: the heart failure group (n=12, intraperitoneal injection of adriamycin hydrochloride 2.5 mg/kg once a week for 6 consecutive weeks, establishing a model of heart failure); heart failure+sacubitril/valsartan group (treatment group, n=12, intragastric administration with sacubitril/valsartan 1 week before the first injection of adriamycin, at a dose of 60 mg·kg^-1·d^-1 for 7 weeks); heart failure+sacubitril/valsartan+APJ antagonist F13A group (F13A group, n=12, adriamycin and sacubitril/valsartan, intraperitoneal injection of 100 μg·kg^-1·d^-1 APJ antagonist F13A for 7 weeks) and control group (n=10, intraperitoneal injection of equal volume of normal saline). One week after the last injection of adriamycin or saline, transthoracic echocardiography was performed to detect the cardiac structure and function, and then the rats were executed, blood and left ventricular specimens were obtained for further analysis. Hematoxylin-eosin staining and Masson trichrome staining were performed to analyze the left ventricular pathological change and myocardial fibrosis. TUNEL staining was performed to detect cardiomyocyte apoptosis. mRNA expression of left ventricular myocardial apelin and APJ was detected by RT-qRCR. ELISA was performed to detect plasma apelin-12 concentration. The protein expression of left ventricular myocardial apelin and APJ was detected by Western blot. Results: Seven rats survived in the heart failure group, 10 in the treatment group, and 8 in the F13A group. Echocardiography showed that the left ventricular end-diastolic diameter (LVEDD) and the left ventricular end-systolic diameter (LVESD) were higher (both P<0.05), while the left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were lower in the heart failure group than in the control group (both P<0.05). Compared with the heart failure group, rats in the treatment group were featured with lower LVEDD and LVESD (both P<0.05), higher LVEF and LVFS (both P<0.05), these beneficial effects were reversed in rats assigned to F13A group (all P<0.05 vs. treatment group). The results of HE staining showed that the cardiomyocytes of rats in the control group were arranged neatly and densely structured, the cardiomyocytes in the heart failure group were arranged in disorder, distorted and the gap between cells was increased, the cardiomyocytes in the treatment group were slightly neat and dense, and cardiomyocytes in the F13A group were featured similarly as the heart failure group. Masson staining showed that there were small amount of collagen fibers in the left ventricular myocardial interstitium of the control group, while left ventricular myocardial fibrosis was significantly increased, and collagen volume fraction (CVF) was significantly higher in the heart failure group than that of the control group (P<0.05). Compared with the heart failure group, the left ventricular myocardial fibrosis and the CVF were reduced in the treatment group (both P<0.05), these effects were reversed in the F13A group (all P<0.05 vs. treatment group). TUNEL staining showed that the apoptosis index (AI) of cardiomyocytes in rats was higher in the heart failure group compared with the control group (P<0.05), which was reduced in the treatment group (P<0.05 vs. heart failure group), this effect again was reversed in the F13A group (P<0.05 vs. treatment group). The results of RT-qPCR and Western blot showed that the mRNA and protein levels of apelin and APJ in left ventricular myocardial tissue of rats were downregulated in heart failure group (all P<0.05) compared with the control group. Compared with the heart failure group, the mRNA and protein levels of apelin and APJ were upregulated in the treatment group (all P<0.05), these effects were reversed in the F13A group (all P<0.05 vs. treatment group). ELISA test showed that the plasma apelin concentration of rats was lower in the heart failure group compared with the control group (P<0.05); compared with the heart failure group, the plasma apelin concentration of rats was higher in the treatment group (P<0.05), this effect was reversed in the F13A group (P<0.05 vs. treatment group). Conclusion: Sacubitril/valsartan can partially reverse left ventricular remodeling and improve cardiac function in rats with heart failure through modulating Apelin/APJ pathways.

Autotrophic respiration modulates the carbon isotope composition of soil respiration in a mixed forest

Carbon isotopic composition of soil respired CO₂ (soil δ¹³C_R) has been regarded as a good indicator of the linkages between aboveground processes and soil respiration. However, whether δ¹³C_R of autotrophic or heterotrophic component of soil respiration dominates the temporal variability of total soil δ¹³C_R was rarely examined by previous studies. In this study, carbon isotopic composition of atmospheric CO₂ (δ¹³C_air) and soil δ¹³C_R in control (with roots) and trenched (without roots) plots were measured in a temperated mixed forest. A ¹³C isotopic profile system and an automated soil respiration system were used for δ ¹³C_air and soil δ¹³C_R measurements, respectively. We found that soil δ¹³C_R in the control plots changed substantially in the growing season and it was more negative (by ~0.6‰) than that in the trenched plots, while soil δ¹³C_R in the trenched plots showed a minor temporal variability. This suggests that δ¹³C_R from the autotrophic respiration is the key decider of the seasonal variation pattern of the soil δ¹³C_R. Moreover, the seasonal variation of soil δ¹³C_R in the control plots showed a similar pattern with the seasonal variation of δ¹³C_air. A significant time-lag was found between δ¹³C_air and soil δ¹³C_R, showing that soil δ¹³C_R generally lagged behind δ¹³C_air 15 days. This result supports the hypothesis that soil respiration is closely related to carbon assimilation at the leaf-level and also stressed the importance of δ¹³C_air in shaping soil δ¹³C_R. These findings are highly valuable to develop the process-based models of the carbon cycle of forest ecosystems.

Successful treatment of pulmonary mucormycosis caused by Rhizopus microsporus with posaconazole

Background

Mucormycosis is a rare fungal infection occurring chiefly in the lung or the rhino-orbital-cerebral compartment, particularly in patients with immunodeficiency or diabetes mellitus. Among Mucorales fungi, Rhizopus spp. are the most common cause of mucormycosis.

Case presentation

We report a case of pulmonary mucormycosis caused by Rhizopus microsporus in a young patient with diabetes but no other apparent risk factors. The diagnosis mainly relied on clinical manifestation, positive pulmonary tissue biopsy, and fungal culture. The patient was successfully treated with posaconazole oral suspension and remains asymptomatic at one-year follow-up.

Conclusions

Pulmonary mucormycosis is a life-threatening condition and posaconazole is an effective treatment for pulmonary mucormycosis caused by Rhizopus microspores.

Salt glands play a pivotal role in the salt resistance of four recretohalophyte Limonium Mill. species

Limonium Mill. plants are typical recretohalophytes, as they withstand salt stress by secreting excess salt onto the leaf surface through salt glands. However, little is known on the salinity thresholds of these plants and the function of salt glands in salt tolerance. Here, we investigated the salinity thresholds of salt tolerance of the Limonium species L. aureum (Linn.) Hill, L. gmelinii (Willd.) Kuntze, L. otolepis (Schrenk) Kuntze and L. sinuatum (L.) Mill grown with various concentrations of NaCl. The salinity thresholds of L. otolepis, L. aureum, L. sinuatum and L. gmelinii were 300, 350, 400 and 420 mm NaCl, respectively. Correlation analysis indicated that total dry weight, chlorophyll content and intercellular CO₂ concentration were highly positively correlated with the total fresh weights of all four Limonium species and could therefore be used as indicators of plant salt tolerance. Furthermore, as the salt gland density on the leaf surface increased, the rate of salt secretion per salt gland also increased, allowing more Na⁺ to be secreted from the plant. Redundancy discriminant analysis indicated that salt gland density, Na⁺ content and Na⁺ secretion rate per salt gland were positively correlated with salt concentration. These observations support the notion that salt glands play important roles in the adaptation of Limonium species to high salinity conditions.

Seawater exposure causes hydraulic damage in dying Sitka-spruce trees

Sea-level rise is one of the most critical challenges facing coastal ecosystems under climate change. Observations of elevated tree mortality in global coastal forests are increasing, but important knowledge gaps persist concerning the mechanism of salinity stress-induced nonhalophytic tree mortality. We monitored progressive mortality and associated gas exchange and hydraulic shifts in Sitka-spruce (Picea sitchensis) trees located within a salinity gradient under an ecosystem-scale change of seawater exposure in Washington State, USA. Percentage of live foliated crown (PLFC) decreased and tree mortality increased with increasing soil salinity during the study period. A strong reduction in gas exchange and xylem hydraulic conductivity (Ks) occurred during tree death, with an increase in the percentage loss of conductivity (PLC) and turgor loss point (πtlp). Hydraulic and osmotic shifts reflected that hydraulic function declined from seawater exposure, and dying trees were unable to support osmotic adjustment. Constrained gas exchange was strongly related to hydraulic damage at both stem and leaf levels. Significant correlations between foliar sodium (Na+) concentration and gas exchange and key hydraulic parameters (Ks, PLC, and πtlp) suggest that cellular injury related to the toxic effects of ion accumulation impacted the physiology of these dying trees. This study provides evidence of toxic effects on the cellular function that manifests in all aspects of plant functioning, leading to unfavourable osmotic and hydraulic conditions.

Comparative efficacy and acceptability of psychosocial treatments for disruptive behaviour disorders in children and adolescents: study protocol for a systematic review and network meta-analysis

INTRODUCTION

Disruptive behaviour disorders are common among children and adolescents, with negative impacts on the youths, their families and society. Although multiple psychosocial treatments are effective in decreasing the symptoms of disruptive behaviour disorders, comprehensive evidence regarding the comparative efficacy and acceptability between these treatments is still lacking. Therefore, we propose a systematic review and network meta-analysis, integrating both direct and indirect comparisons to obtain a hierarchy of treatment efficacy and acceptability.

METHODS AND ANALYSIS

The present protocol will be reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols. Ten databases, including Web of Science, PubMed, PsycINFO, MEDLINE, APA PsycArticles, Psychology and Behavioral Sciences Collection, OpenDissertations, The Cochrane Library, Embase and CINAHL, will be searched from inception for randomised controlled trials of psychosocial treatments for children and adolescents with disruptive behaviour disorders, without restrictions on language, publication year and status. The primary outcomes will be efficacy at post-treatment (severity of disruptive behaviour disorders at post-treatment) and acceptability (dropout rate for any reason) of psychosocial treatments. The secondary outcomes will involve efficacy at follow-up, severity of internalising problems and improvement of social functioning. Two authors will independently conduct the study selection and data extraction, assess the risk of bias using the revised Cochrane Collaboration's Risk of Bias tool and evaluate the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation framework to network meta-analysis. We will perform Bayesian network meta-analyses with a random effects model. Subgroup and sensitivity analyses will be performed to evaluate the robustness of the findings.

ETHICS AND DISSEMINATION

The research does not require ethical approval. Results are planned to be published in journals or presented at conferences. The network meta-analysis will provide information on a hierarchy of treatment efficacy and acceptability and help make a clinical treatment choice.

PROSPERO REGISTRATION NUMBER

CRD42020197448.

Exosomes derived from Taxol-resistant nasopharyngeal carcinoma (NPC) cells transferred DDX53 to NPC cells and promoted cancer resistance to Taxol

OBJECTIVE

Nasopharyngeal carcinoma (NPC) is a common cancer with high incidence in Southern China. Taxol is one of the first-line chemotherapeutic drugs for treating NPC; however, Taxol resistance has become the main difficulty for clinical treatment and the mechanisms remain not fully understood. In this study, we mainly focus on exploring whether exosomes from Taxol-resistant NPC cells played some roles in the resistance and progression of NPC.

MATERIALS AND METHODS

Taxol was used to treat NPC cell line CNE1 and Taxol-resistant NPC cell line CNE1-TR cells to measure cell viability and IC50 by CCK-8 assay. Exosomes from these two cells were extracted and identified by transmission electron microscopy (TEM), and special protein markers were determined by Western blot (WB) assay. Real-time PCR was performed to detect levels of mRNAs in exosomes, CNE1 and CNE1-TR cells. WB was performed to detect protein levels. The p-DDX53 and si-DDX53 were constructed and cloned into cells, resulted with DDX53 overexpression and inhibition, then resistant associated protein levels and IC50 were measured. Finally, GW4869, an inhibitor to block exosome secretion, was used to verify that the exosomes derived from CNE1-TR cells transferred DDX53 to CNE1 cells and contributed to promote NPC resistance.

RESULTS

We found that the IC50 to Taxolin CNE1-TR was much higher than that in CNE1 cells and DDX53 was highly expressed in Taxol-resistant CNE1-TR cells. Furthermore, exosomes were successfully extracted and determined, showing high levels of DDX53 and MDR1. Thus, they could promote cell resistance for CNE1 after adding CNE1-TR exosomes into CNE1 cells. Moreover, DDX53 overexpression increased the IC50 and upregulated MDR1 in CNE1 cells, while DDX53 inhibition showed the opposite results. In addition, the DDX53 inhibition decreased the IC50 and repressed MDR1 in CNE1-TR cells. Besides, blocking exosome released from CNE1-TR by using GW4869 treatment significantly repressed the levels of DDX53 and MDR1, and the IC50 of CNE1 cells was reversed. Finally, the increased levels of MDR1 were significantly reversed following with adding DDX53 si-DDX53-CNE1-TR exosomes, and the increased IC50 to Taxol was obviously reversed.

CONCLUSIONS

This study firstly discovered that DDX53 was highly expressed in Taxol-resistant NPC cells, which could be transferred into normal NPC cells via exosome secretion. The transferred DDX53 could upregulate the expression of MDR1 in NPC cells to promote the resistant capacity to Taxol, which provided a novel insight for understanding NPC and might be a potential therapeutic target for NPC.

POS0320 POOR PROGNOSIS PREDICTION IN ANTI-MDA5 POSITIVE DERMATOMYOSITIS ASSOCIATED WITH INTERSTITIAL LUNG DISEASE: THE CROSS-CAR DECISION TREE MODEL

Background:

The prognosis of anti-melanoma differentiation-associated gene 5 positive dermatomyositis (anti-MDA5+ DM) – associated interstitial lung disease (ILD) is poor and heterogeneity.

Objectives:

The aim of this study was to evaluate prognostic factors and to develop a simple and generally applicable bedside decision tree model for predicting outcomes in patients with anti-MDA5+ DM and to guide treatment.

Methods:

We analyzed data for 246 anti-MDA5+ DM patients from Myositis Study Group-Jiangsu, a multicenter cohort across eighteen tertiary hospitals in Jiangsu province, from March 2019 to October 2020. The primary end point was all-cause death, and the secondary end point was occurring of rapidly progressive-ILD (rp-ILD). We used a multivariable Cox proportional hazards model to identify the independent prognostic risk factors of death and rp-ILD respectively. A decision-tree prediction model was developed by using data from 10 hospital of southern region (n=163), with validation by using contemporaneous data from northern region (n=83).

Results:

To assess the risk of rp-ILD, we developed a combined risk score, the CROSS score, that included the following values and scores: C-reactive protein (≤8mg/L, 0; >8mg/L, 3), anti-Ro52 antibody (negative, 0; positive, 4), Sex (Female, 0; Male, 2) and Short course of disease (More than 3 months, 0; Less than 3 months, 2). The mortality risk was identified by the CAR score, including C-reactive protein (≤8mg/L, 0; >8mg/L, 1), Alanine Transaminase (≤50units/L, 0; >50units/L, 1) and rp-ILD (non-rpILD, 0; rp-ILD, 3). We divided patients into three risk groups according to the CROSS score: low, 0 to 3; medium, 4 to 7; and high 8-11. And then Use of a simple decision tree prediction model permitted stratification into three different outcome prediction groups. High-risk patients had significantly higher mortality rates than low- and medium-risk patients in both discovery and validation cohorts (p < 0.0001).

Conclusion:

The CROSS-CAR decision tree model is easy to evaluate the poor prognostic risk in MDA5+ DM patients during any follow-up period. Unnecessary lung examination, such as chest CT scan and arterial blood gas analysis was avoided in low- and medium- rpILD risk patients. The special ambulance, with red cross sign tagged on car in China, may help to screen the high risk patients and to guide further treatment.

Disclosure of Interests:

None declared

Autophagy related 4B, upregulated by HIF-1α, attenuates the sensitivity to cisplatin in nasopharyngeal carcinoma cells

OBJECTIVE

Increasing evidence has shown that autophagy related proteins and hypoxia-inducible factor-1α (HIF-1α) are both involved in the malignant progress of nasopharyngeal carcinoma (NPC), and HIF-1α plays an emerging role in the chemosensitivity of NPC cells. However, it is still unknown whether autophagy related proteins are associated with HIF-1α in regulating the chemosensitivity of NPC cells.

MATERIALS AND METHODS

Quantitative Real-time PCR (qPCR) was applied to determine mRNA levels of HIF-1α and the autophagy related proteins, such as ATG3, ATG4B, ATG5, Beclin1, ATG7, ATG10, ATG12 and ATG16L1. Western blot was applied to determine protein levels of HIF-1α, ATG4B and cleaved Caspase-3. Cell viability and death were investigated by cell counting kit-8 and trypan blue exclusion assay. In addition, Caspase-3 activity was detected to reflect apoptosis. Furthermore, Luciferase reporter assay was applied to explore the mechanism by which HIF-1α transcriptionally upregulated ATG4B expression.

RESULTS

Our study reveals that HIF-1α increased ATG4B expression in NPC cells, and in turn upregulated the cisplatin (DDP)-induced protective autophagy, resulting in enhanced killing effect of DDP to NPC cells. In mechanism, reporter assay showed that HIF-1α upregulated ATG4B expression by activating its gene promoter region. The binding site (-225 to -216) was required for HIF-1α-induced increase of ATG4B gene promoter activity.

CONCLUSIONS

These results indicate that HIF-1α elevates ATG4B via promoting its transcription, which alleviates the sensitivity of DDP in NPC cells through enhancing protective autophagy, suggesting that ATG4B, upregulated by HIF-1α, may be a novel target for DDP sensitization in the treatment of NPC in clinic.