ObjectiveThe biosynthesis of heterophyllin B （HB）， a cyclopeptide from Pseudostellaria heterophylla， is regulated by various abiotic stresses. Elucidating the transcriptional regulatory mechanism underlying HB biosynthesis is of great guiding significance for the directional improvement of P. heterophylla varieties and the enhancement of HB content. MethodsBased on transcriptome data from different tissues of P. heterophylla， transcription factors （TFs） specifically upregulated and highly expressed in the phloem of tuberous roots were screened through a combination of Mfuzz time-series clustering， transcription factor family prediction， and correlation analysis. Quantitative real-time polymerase chain reaction （Real-time PCR） was employed to analyze expression patterns of candidate TFs under abscisic acid （ABA） induction， and the dual-luciferase reporter assay was applied to verify their regulatory effects on HB precursor genes. ResultsContent determination showed that HB accumulated at the highest in the phloem of P. heterophylla tuberous roots （34 μg·g^-1 fresh weight）. Transcriptome analysis identified 15 868 up-regulated differentially expressed genes （DEGs）， among which 4 375 were specifically up-regulated in the phloem. From these， 25 TFs highly expressed in the phloem were screened. Correlation analysis revealed that the expression level of WRKY70 was significantly positively correlated with HB content， the expression of precursor genes prePhHB， and PhPOP1. Additionally， WRKY70 expression was significantly upregulated under ABA induction. Dual-luciferase reporter assay confirmed that WRKY70 specifically activated the transcriptional activity of the prePhHB promoter （Pro-prePhHB）. ConclusionHB is mainly accumulated in the phloem of P. heterophylla tuberous roots. WRKY70 positively regulates HB biosynthesis by directly activating the promoter activity of prePhHB. This study clarifies the key role of WRKY70 in the regulation of HB biosynthesis and provides an important theoretical basis for the in-depth analysis of the molecular regulatory mechanism underlying HB biosynthesis.

Objective:To investigate the factors affecting the application of systemic glucocorticoids in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with carbon dioxide (CO 2) retention, and to guide the formulation of a strategy to reduce systemic glucocorticoid exposure. Methods:The AECOPD patients with CO 2 retention admitted to the Ningde Municipal Hospital of Fujian Medical University from January 2017 to December 2019 were enrolled. The general information, past history, times of acute exacerbations within 1 year, pneumonia on admission, causes of COPD, heart failure, blood gas analysis, eosinophil count (EOS), albumin (Alb) and apolipoprotein E (ApoE) levels, exhaled nitric oxide (FeNO) level, inhaled glucocorticoid and non-invasive mechanical ventilation treatment at acute exacerbation were collected. The patients were divided into recommended dosage group (exposure levels in the recommended dosage range, cumulative prednisone dosage ≤ 200 mg) and exceeded group (exposure levels exceeded the recommended dose, cumulative prednisone dosage > 200 mg) according to cumulative systemic glucocorticoid exposure dosage of the patients during hospitalization. The clinical data of patients between the two groups were compared, and possible factors with P < 0.1 in univariate analysis were included in multivariate Logistic regression analysis to screen the related factors of systemic glucocorticoid exposure level in AECOPD patients with CO 2 retention. Results:According to the order of hospitalization, 151 AECOPD patients with CO 2 retention were enrolled, 8 patients were excluded, and 143 patients were enrolled in the analysis. Of the 143 patients, 68 received the recommended dose of systemic glucocorticoid, and 75 received excessive systemic glucocorticoid. Age, percentage of forced expiratory volume in 1 second (FEV1%) at stable phase, frequency of acute exacerbation within 1 year, heart failure ratio, oxygen index (PaO 2/FiO 2), arterial partial pressure of carbon dioxide (PaCO 2), serum EOS and ApoE levels at admission, the ratio of aerosolized inhaled glucocorticoids and non-invasive mechanical ventilation showed statistical differences between the two groups. Multivariate Logistic regression analysis showed that related factors affecting systemic glucocorticoid exposure levels of AECOPD patients with CO 2 retention were FEV1% at stable phase [odds ratio ( OR) = 0.957, 95% confidence interval (95% CI) was 0.921-0.994, P = 0.023], acute exacerbation frequency within 1 year ( OR = 1.530, 95% CI was 1.121-2.088, P = 0.007), heart failure ( OR = 3.022, 95% CI was 1.263-7.231, P = 0.013), PaCO 2 ( OR = 1.062, 95% CI was 1.010-1.115, P = 0.018) and EOS at admission ( OR = 0.103, 95% CI was 0.016-0.684, P = 0.019), aerosolized inhaled glucocorticoids ( OR = 0.337, 95% CI was 0.145-0.783, P = 0.011) and non-invasive mechanical ventilation at acute exacerbation ( OR = 0.422, 95% CI was 0.188-0.948, P = 0.037), of which high FEV1% at stable phase, high EOS at admission, aerosolized inhaled glucocorticoid and non-invasive mechanical ventilation at acute exacerbation were protective factors, while high frequency of acute exacerbation within 1 year, heart failure and high PaCO 2 were risk factors. Conclusions:For AECOPD patients with CO 2 retention, high FEV1% at stable phase, high EOS level at admission, aerosolized inhaled glucocorticoid and non-invasive mechanical ventilation at acute exacerbation can reduce systemic glucocorticoid exposure. In addition, high frequency of acute exacerbation within 1 year, heart failure, and high PaCO 2 can increase systemic glucocorticoid exposure.