White blood cell labeling with Technetium-99m (99mTc) using red blood cell extracellular vesicles-mimetics.

BACKGROUND: Extracellular vesicles, have gained increasing attention for their application in drug delivery. Here, we developed a novel method for radiolabeling WBCs with 99mTc using RBC-derived extracellular vesicles -mimetics (EVMs), and monitored in vivo inflammation tracking of 99mTc-WBC using gamma camera in acute inflammation mouse model. METHODS: Engineered EVMs from RBCs were produced by a one-step extrusion method. RBC-EVMs were analyzed by NTA and TEM. Cells were labeled with 99mTc by using 99mTc-RBC-EVMs. Inflammation mice model was prepared and confirmed by 18F-FDG PET/CT. 99mTc-WBCs were injected in mice, and their biodistribution was analyzed by gamma camera. FINDING: The radiochemical purity of 99mTc-RBC-EVMs was 100%. The 99mTc-labeling did't affect the size and morphology. The 99mTc in the cytoplasm of RBC-EVMs was successfully confirmed by high angle annular dark field STEM (scanning transmission electron microscope). Cells were successfully labeled with 99mTc using 99mTc-RBC-EVMs, and the counts per minute was increased in dose- and time-dependent manners. The 18F-FDG PET/CT images confirmed establishment of acute inflammation (left mouse foot). 99mTc-WBCs showed higher uptake in the inflamed foot than non-inflamed foot. INTERPRETATION: This novel method for radiolabeling WBCs using RBC-EVMs. 99mTc labeling may be a feasible method to monitor the in vivo biodistribution of cells.

PROGNOSTIC VALUE OF LYMPH NODE UPTAKE ON PRETREATMENT F-18 FDG PET/CT IN PATIENTS WITH N1B PAPILLARY THYROID CARCINOMA.

Objective: The aim of this study was to investigate the prognostic value of metabolic characteristics of metastatic lymph node (LN) using pretreatment F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for patients with papillary thyroid carcinoma (PTC) and metastatic lateral LN (N1b). Methods: Ninety-six PTC patients (female:male = 72:24; median age, 44.5 years) with pathologic N1b who underwent pretreatment FDG PET/CT, total thyroidectomy, and radioactive iodine ablation were retrospectively reviewed. To predict responses to initial therapy and recurrence, clinicopathologic factors and metabolic parameters were reviewed, such as sex, age, tumor size, extranodal extension, number and ratio of metastatic LNs, serum thyroglobulin, and maximum standardized uptake value (SUVmax). Results: Among the 96 PTC patients, 81 (84.4%) were classified into the acceptable response (58 excellent; 23 indeterminate) and 15 (15.6%) into the incomplete response (8 biochemical incomplete; 7 structural incomplete) by the 2015 American Thyroid Association management guideline for differentiated thyroid carcinoma. The multivariate analysis showed that SUVmax of N1b (P = .018), pre-ablation stimulated thyroglobulin level (P = .006), and the ratio of metastatic LNs (P = .018) were related to incomplete response. The cutoff value of each variable was determined by receiver operating characteristic analysis. Nine (9.4%) patients experienced recurrences (median follow-up: 50 months). The Kaplan-Meier analysis revealed that SUVmax of N1b (cutoff value: 2.3; P = .025) and ratio of metastatic LNs (cutoff value: 0.218; P = .037) were significant prognostic factors for recurrence. Conclusion: High SUVmax of N1b cervical LN on pretreatment FDG PET/CT could predict incomplete responses to initial therapy and recurrence in patients with N1b PTC. Abbreviations: ATA = American Thyroid Association; DTC = well-differentiated thyroid carcinoma; FDG = F-18 fluorodeoxyglucose; IQR = interquartile range; LN = lymph node; N1b = metastatic lateral cervical lymph node; PET/CT = positron emission tomography/computed tomography; PTC = papillary thyroid carcinoma; RAI = radioactive iodine; ROC = receiver operating characteristic; SUVmax = maximum standardized uptake value; Tg = thyroglobulin; USG = ultrasonography.

Function and molecular regulation of DWARF1 as a C-24 reductase in brassinosteroid biosynthesis in Arabidopsis.

DWARF1 (DWF1) is a sterol C-24 reductase that catalyses the conversion of 24-methylenecholesterol (24-MCHR) to campesterol (CR) in Arabidopsis. A loss-of-function mutant, dwf1, showed similar phenotypic abnormalities to brassinosteroid (BR)-deficient mutants. These abnormalities were reversed in the wild-type phenotype by exogenous application of castasterone (CS) and brassinolide (BL), but not dolichosterone (DS). Accumulation of DS and decreased CS were found in quantitative analysis of endogenous BRs in dwf1. The enzyme solution prepared from dwf1 was unable to convert 6-deoxoDS to 6-deoxoCS and DS to CS, as seen in either wild-type or 35S:DWF1 transgenic plants. This suggests that DWF1 has enzyme activity not only for a sterol C-24 reductase, but also for a BR C-24 reductase that catalyses C-24 reduction of 6-deoxoDS to 6-deoxoCS and of DS to CS in Arabidopsis. Overexpression of DWF1 in a BR-deficient mutant (det2 35S:DWF1) clearly rescued abnormalities found in det2, indicating that DWF1 functions in biosynthesis of active BRs in Arabidopsis. Expression of DWF1 is down-regulated by application of CS and BL and in a BR-dominant mutant, bes1-D. E-boxes in the putative promoter region of DWF1 directly bind to a BR transcription factor, BES1, implying that DWF1 expression is feedback-regulated by BR signaling via BES1. Overall, biosynthesis of 24-methylene BR is an alternative route for generating CS, which is mediated and regulated by DWF1 in Arabidopsis.

Profiling of the Major Phenolic Compounds and Their Biosynthesis Genes in Sophora flavescens Aiton.

Sophorae Radix (Sophora flavescens Aiton) has long been used in traditional medicine in East Asia due to the various biological activities of its secondary metabolites. Endogenous contents of phenolic compounds (phenolic acid, flavonol, and isoflavone) and the main bioactive compounds of Sophorae Radix were analyzed based on the qualitative HPLC analysis and evaluated in different organs and at different developmental stages. In total, 11 compounds were detected, and the composition of the roots and aerial parts (leaves, stems, and flowers) was significantly different. trans-Cinnamic acid and p-coumaric acid were observed only in the aerial parts. Large amounts of rutin and maackiain were detected in the roots. Four phenolic acid compounds (benzoic acid, caffeic acid, ferulic acid, and chlorogenic acid) and four flavonol compounds (kaempferol, catechin hydrate, epicatechin, and rutin) were higher in aerial parts than in roots. To identify putative genes involved in phenolic compounds biosynthesis, a total of 41 transcripts were investigated. Expression patterns of these selected genes, as well as the multiple isoforms for the genes, varied by organ and developmental stage, implying that they are involved in the biosynthesis of various phenolic compounds both spatially and temporally.

The bHLH transcription factor HBI1 mediates the trade-off between growth and pathogen-associated molecular pattern-triggered immunity in Arabidopsis.

The trade-off between growth and immunity is crucial for survival in plants. However, the mechanism underlying growth-immunity balance has remained elusive. The PRE-IBH1-HBI1 tripartite helix-loop-helix/basic helix-loop-helix module is part of a central transcription network that mediates growth regulation by several hormonal and environmental signals. Here, genome-wide analyses of HBI1 target genes show that HBI1 regulates both overlapping and unique targets compared with other DNA binding components of the network in Arabidopsis thaliana, supporting a role in specifying network outputs and fine-tuning feedback regulation. Furthermore, HBI1 negatively regulates a subset of genes involved in immunity, and pathogen-associated molecular pattern (PAMP) signals repress HBI1 transcription. Constitutive overexpression and loss-of-function experiments show that HBI1 inhibits PAMP-induced growth arrest, defense gene expression, reactive oxygen species production, and resistance to pathogen. These results show that HBI1, as a component of the central growth regulation circuit, functions as a major node of crosstalk that mediates a trade-off between growth and immunity in plants.

Quantitative metabolic parameters measured on F-18 FDG PET/CT predict survival after relapse in patients with relapsed epithelial ovarian cancer.

OBJECTIVE: This study aimed to evaluate the prognostic value of quantitative metabolic parameters measured on F-18 FDG PET/CT (FDG PET/CT) at the time of the first relapse in patients with relapsed epithelial ovarian cancer (EOC). METHODS: Fifty-six relapsed EOC patients were retrospectively included. Quantitative metabolic parameters including maximum standardized uptake value (SUVmax), whole-body metabolic tumor volume (WBMTV), and whole-body total lesion glycolysis (WBTLG) were measured on FDG PET/CT at the time of the first relapse. Post-relapse survival (PRS) was calculated from the date of diagnosis of relapsed disease to the date of death or last follow-up. Univariate and multivariate analyses for PRS were performed using clinical and quantitative metabolic parameters. RESULTS: Thirty-two patients died from the disease during the follow-up period (median: 46.2 months). On univariate and multivariate analyses, the platinum-free interval, type of second-line treatment, WBMTV, and WBTLG were all significant prognostic factors for PRS. The subgroup of patients who were platinum-sensitive with low WBMTV and low WBTLG showed better prognosis, when compared with other subgroups (log-rank test, p<0.001). Patients treated with secondary cytoreductive surgery (SCS) followed by second-line chemotherapy showed significantly longer duration of PRS than patients treated with second-line chemotherapy only (mean PRS=61 vs. 36 months, χ(2)=8.68, p=0.032). CONCLUSION: Our results suggest that quantitative metabolic parameters measured on FDG PET/CT at the time of the first relapse have significant predictive values for PRS. Incorporating quantitative metabolic parameters and conventional clinical parameters has a superior prognostic discrimination compared with conventional clinical parameters alone.

Occurrence of phosphorylated castasterone in Arabidopsis thaliana and Lycopersicum esculentum.

An in vitro enzyme assay using radioisotope-labeled (3) H-castasterone ((3) H-CS) or (32) P-ATP showed that CS can be phosphorylated by ATP in Arabidopsis and tomato plants. Gas chromatography-mass spectrometry (GC-MS) analysis using non-isotope-labeled CS and ATP revealed that the phosphorylation of CS occurs at the side chain, most likely at the C-23 hydroxyl. The polar fractions than free brassinosteroids (BRs) obtained from extracts of Arabidopsis and tomato showed almost no BRs activity in a rice lamina inclination bioassay. However, the fractions showed increased bioactivity after treatment with wheat germ acidic phosphatase (WGAP). Additionally, CS was identified from the hydrolysate by WGAP using GC-MS analysis in both plants. In contrast, the polar fractions obtained from BR-deficient mutants, Arabidopsis cyp85a2 and tomato d(x) , did not show an increase in biological activity with WGAP treatment, and no free BRs, including CS, were detected in the hydrolysate. This suggests that CS phosphate is a naturally occurring biologically inactive conjugate that is generated when CS is normally synthesized in Arabidopsis and tomato plants. Taken together, these results suggest that phosphorylation of CS is an important conjugation process for the maintenance of the homeostatic level of an active BR and thus the regulation of the growth and development of plants.

Whole-Body Metabolic Tumor Volume, as Determined by (18)F-FDG PET/CT, as a Prognostic Factor of Outcome for Patients With Breast Cancer Who Have Distant Metastasis.

OBJECTIVE: This study was performed to evaluate the prognostic relevance of PET parameters measured by (18)F-FDG PET/CT in patients with invasive ductal carcinoma of the breast (IDC) who had distant metastasis at the time of initial diagnosis. MATERIALS AND METHODS: Forty women with IDC who had distant metastasis at the time of initial diagnosis and who underwent FDG PET/CT before receiving treatment were enrolled in the study. Clinicopathologic parameters and metabolic PET parameters, including the maximum standardized uptake value (SUVmax) of the primary tumor (pSUVmax), the SUVmax of the axillary lymph node (nSUVmax), the highest SUVmax of whole malignant lesions (wSUVmax), the whole-body (WB) metabolic tumor volume (MTV), and WB total lesion glycolysis (TLG), were analyzed to determine their usefulness in predicting overall survival (OS). Univariate and multivariate analyses were performed with the use of Kaplan-Meier and Cox proportional hazards models. RESULTS: Twenty-one of the 40 patients (52.5%) died during follow-up (mean follow-up, 36.4 months; range, 0.8-71.4 months). Nonsurvivors had a statistically significantly higher mean (± SD) WB MTV than did survivors (424.0 ± 683.9 vs 92.1 ± 96.3 cm(3); p = 0.0430). T category, performance of palliative surgery, presence of visceral metastasis, wSUVmax, WB MTV, and WB TLG were identified by univariate analysis as prognostic factors for OS, whereas age, N category, hormone receptor status, status, triple-negative breast cancer status (defined as a tumor for which estrogen receptor, progesterone receptor, and ERBB2 statuses were all negative), pSUVmax, and nSUVmax were not. Multivariate analysis revealed that only WB MTV independently predicted OS (hazard ratio, 4.10; 95% CI, 1.17-14.31; p = 0.0280). CONCLUSION: The WB MTV value, as determined by FDG PET/CT performed before treatment, was found to be an independent prognostic factor for OS in patients with IDC who had distant metastasis at the time of initial diagnosis.

BAT1, a putative acyltransferase, modulates brassinosteroid levels in Arabidopsis.

Brassinosteroids (BRs) are essential for various aspects of plant development. Cellular BR homeostasis is critical for proper growth and development of plants; however, its regulatory mechanism remains largely unknown. BAT1 (BR-related acyltransferase 1), a gene encoding a putative acyltransferase, was found to be involved in vascular bundle development in a full-length cDNA over-expressor (FOX) screen. Over-expression of BAT1 resulted in typical BR-deficient phenotypes, which were rescued by exogenously applied castasterone and brassinolide. Analyses of BR profiles demonstrated that BAT1 alters levels of several brassinolide biosynthetic intermediates, including 6-deoxotyphasterol, typhasterol and 6-deoxocastasterone. BAT1 is mainly localized in the endoplasmic reticulum. BAT1 is highly expressed in young tissues and vascular bundles, and its expression is induced by auxin. These data suggest that BAT1 is involved in BR homeostasis, probably by conversion of brassinolide intermediates into acylated BR conjugates.

A subset of Arabidopsis RAV transcription factors modulates drought and salt stress responses independent of ABA.

Arabidopsis RAV1, RAV1L and RAV2/TEM2 are Related to ABI3/VP1 (RAV) transcription factors that contain both plant-specific B3 and AP2 domains. RAV1 was known to be a negative regulator of growth and its transcript level was repressed by brassinolide (BL). In this study, we found that the expressions of RAV1, and its closest homologs RAV1L and RAV2 were also regulated by other plant hormones, and especially repressed significantly by BL and abscisic acid (ABA), which mediate various abiotic stress responses in plants. Therefore, to further investigate the physiological functions of RAV1, RAV1L and RAV2 in abiotic stress responses, we isolated T-DNA insertional knockout mutants of each gene and produced transgenic plants overexpressing the RAVs. Under normal conditions, each single mutant showed slightly promoted growth patterns only at an early stage of development. In comparison, the RAV1-overexpressing plants exhibited strong growth retardation with semi-dwarfed stature. In drought conditions, RAVs-overexpressing transgenic plants exhibited higher transpirational water loss than the wild type. In salt conditions, seed germination of the RAVs-overexpressing transgenic plants was more inhibited than that of the wild type, while ravs mutants showed promoted seed germination. We also found that RAVs expressions were reduced by dryness and salt. RAV1-overexpressing plants showed the same patterns of increased expression as stress-inducible genes such as RD29A, RD29B and the genes encoding ABA biosynthetic enzymes, as did the wild type and rav1 mutant. However, the RAV1-overexpressing transgenic plants were insensitive to ABA, regardless of the higher accumulation of ABA even in normal conditions. Taken together, these results suggest that RAVs are versatile negative regulators for growth and abiotic stresses, drought and salt, and that negative regulatory effects of RAVs on abiotic stresses are likely to be operated independently of ABA.

Prediction for recurrence using F-18 FDG PET/CT in pathologic N0 lung adenocarcinoma after curative surgery.

BACKGROUND: The aim of this study was to investigate risk factors for recurrence in patients with lung adenocarcinoma (LAD) who were pathologically N0 (pN0) after curative surgical resection. METHODS: A total of 102 LAD patients (M/F = 55/47, mean age, 62.6 ± 9.4 years) diagnosed as pN0 after curative surgery were included in this study. Clinical, biochemical, radiologic, and pathologic findings were reviewed and analyzed for recurrence. Metabolic parameters [SUVmax, metabolic tumor volume (MTV), total lesion glycolysis (TLG)] on pretreatment F-18 FDG PET/CT were also obtained and analyzed for recurrence. RESULTS: Of 102 patients, 38 (37.3%) were found to experience recurrence for 33.6 ± 16.3 months. SUVmax, MTV, and TLG were significantly higher in patients with recurrence. The optimal cutoff values determined using a receiver-operating characteristic curve were 6.90 for SUVmax, 10.78 cm(3) for MTV, and 39.68 for TLG. Univariate analysis showed that tumor size, tumor marker, SUVmax, MTV, and TLG were prognostic factors for recurrence. In multivariate analyses, after adjusting for age, sex, tumor size, pathologic T stage, and tumor marker, high SUVmax, MTV, and TLG showed an association with an increased risk of recurrence. CONCLUSIONS: Metabolic parameters on pretreatment F-18 FDG PET/CT can predict recurrence in pN0 LAD patients who underwent curative surgery. Therefore, patients with high metabolic parameters on PET can be considered as candidates for adjuvant therapy to reduce recurrence and should be monitored carefully for early detection of possible recurrence.

Prognostic implication of intratumoral metabolic heterogeneity in invasive ductal carcinoma of the breast.

BACKGROUND: The purpose of this study was to evaluate the prognostic implication of findings of intratumoral metabolic heterogeneity on pretreatment (18)F-FDG PET/CT scans in patients with invasive ductal carcinoma (IDC) of the breast. METHODS: One hundred and twenty-three female IDC patients who underwent pretreatment 18F-fluorodeoxyglucose positron-emission tomography/computed tomography ((18)F-FDG PET/CT) scans were retrospectively evaluated in this study. The heterogeneity factor (HF) defined as the derivative (dV/dT) of a volume threshold function from 40% to 80%, was computed for each primary tumor. Other metabolic PET parameters (maximum standardized uptake value [SUVmax], metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) were measured. The HF was compared with clinicopathologic factors and other PET parameters. Univariate and multivariate analyses for the overall survival (OS) were performed. RESULTS: The HF ranged from 0.02 to 6.72 (mean, 0.35 ± 0.82) and significantly correlated with MTV (r = 0.955; p < 0.0001) and TLG (r = 0.354; p = 0.0001). The HF was significantly higher (implying more heterogeneity) in tumors with higher T and N stages. The optimal cut-off values for the OS determined using a receiver operating characteristic (ROC) curve were 0.34 for the HF, 5.6 for SUVmax, 8.55 cm(3) for MTV, and 14.43 for TLG. The OS rate among the 123 patients was 86.2%. T stage (1, 2 vs. 3, 4), N stage (0, 1 vs. 2, 3), M stage (0 vs. 1), ER status (+ vs. -), SUVmax (≤ 5.6 vs. > 5.6), MTV (≤ 8.55 cm(3) vs. > 8.55 cm(3)), TLG (≤ 14.43 vs. > 14.43), and HF (< 0.34 vs. ≥ 0.34) affected the OS on univariate analysis. After adjustment for the effects of TNM stage and ER status, the HF and MTV were significant predictors of OS. Among the PET parameters, the best prognostic factor for OS was the HF. CONCLUSIONS: Intratumoral metabolic heterogeneity correlated closely with the MTV and significantly affected the OS in IDC patients. The HF may act as a robust surrogate marker for the prediction of OS in IDC patients.

Prognostic value of whole-body metabolic tumour volume and total lesion glycolysis measured on ¹8F-FDG PET/CT in patients with extranodal NK/T-cell lymphoma.

PURPOSE: The aim of this study was to determine whether maximum standardized uptake value (SUVmax), whole-body metabolic tumour volume (WBMTV), and whole-body total lesion glycolysis (WBTLG) measured on pretreatment ¹8F-FDG PET/CT can predict prognosis in patients with extranodal natural killer/T-cell lymphoma (ENKTL). METHODS: We conducted a retrospective analysis of 20 patients with newly-diagnosed ENKTL who underwent pretreatment ¹8F-FDG PET/CT. WBMTV and WBTLG were measured automatically using the boundaries of voxels presenting SUV>3.0. Uni- and multivariate analyses for survival and disease progression were performed using clinical variables and PET parameters (SUVmax, WBMTV, and WBTLG). RESULTS: During the follow-up period (median 26.3 months), 12 patients showed disease progression and 10 patients died from the disease. Receiver operating characteristic curve analysis showed cut-off values for SUVmax, WBMTV and WBTLG of 8.1, 14.4 cm³ and 52.7, respectively. Univariate analysis showed that the International Prognostic Index (IPI) score and PET parameters were significant predictors of overall survival (OS) and progression-free survival (PFS). Multivariate analysis, even after adjustment for the IPI score, showed that high WBMTV was the best predictor of OS and PFS, and high SUVmax and WBTLG were significant predictors of PFS. CONCLUSION: Our results suggested that the use of PET parameters together with the IPI score may be useful for detailed prediction of prognosis in ENKTL patients. Therefore, despite a lower IPI score, patients with high PET parameter values might be considered candidates for aggressive therapy to improve clinical outcomes.

Brain FDG PET for visualizing the relation between impaired lung function and cognitive decline in lung cancer: a preliminary study.

OBJECTIVE: Impaired lung function is associated with an increased risk for cognitive decline. F-18 fluorodeoxyglucose (FDG) PET is a well-known neurodegenerative biomarker for dementia. We investigated the association between lung and brain function using FDG PET in patients with lung cancer. METHODS: A random sub-sample of 102 patients with lung cancer and without a self-reported history of neuropsychiatric disorders were recruited and underwent both lung function tests and FDG PET scans before treatment. Lung function was analyzed as the percentage predicted value (% pred) of forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1). FDG uptake was measured as standardized uptake values (SUVs) in the frontal, parietal, temporal, and occipital cortices and cognition-related regions. Regional SUV ratios (SUVRs) were calculated by dividing the SUV in each region by the whole-brain SUV and were then evaluated against lung function indices and clinical variables. RESULTS: After excluding five patients with brain metastases, 97 patients were included in the final analysis (mean age, 67.7 ± 10.3 years). Mean FVC and mean FEV1 were 80.0% ± 15.4% and 77.6% ± 17.8%, respectively. Both FVC and FEV1 were positively correlated with SUVRs in all brain regions after adjusting the data for clinical variables. The degree of decrease in SUVRs related to lung function was not significantly different between cognition-related regions and other regions. CONCLUSION: Impaired lung function was associated with decreased glucose metabolism in all regions of the brain, indicating that cognitive decline related to decreased glucose metabolism may be due to reduced perfusion.

Biosynthesis of a cholesterol-derived brassinosteroid, 28-norcastasterone, in Arabidopsis thaliana.

A metabolic study revealed that 28-norcastasterone in Arabidopsis is synthesized from cholesterol via the late C-6 oxidation pathway. On the other hand, the early C-6 oxidation pathway was found to be interrupted because cholestanol is converted to 6-oxocholestanol, but further metabolism to 28-norcathasterone was not observed. The 6-oxoBRs were found to have been produced from the respective 6-deoxoBRs administered to the enzyme solution, thus indicating that these 6-oxoBRs are supplied from the late C-6 oxidation pathway. Heterologously expressed CYP85A1 and CYP85A2 in yeast catalysed this C-6 oxidation, with CYP85A2 being much more efficient than CYP85A1. Abnormal growth of det2 and dwf4 was restored via the application of 28-norcastasterone and closer precursors. Furthermore, det2 and dwf4 could not convert cholesterol to cholestanol and cholestanol to 6-deoxo-28-norcathasterone, respectively. It is, therefore, most likely that the same enzyme system is operant in the synthesis of both 28-norcastasterone and castasterone. In the presence of S-adenosyl-L-methionine, the cell-free enzyme extract catalysed the C-24 methylation of 28-norcastasterone to castasterone, although the conversion rates of 28-norteasterone to teasterone and 28-nortyphasterol to typhasterol were much lower; this suggests that 28-norcastasterone is the primary precursor for the generation of C(28)-BRs from C(27)-BRs.

Ethylene negatively regulates EXPA5 expression in Arabidopsis thaliana.

We examined the effects of ethylene on the expression of Arabidopsis expansins (AtEXPs). Among the AtEXPs tested, transcription of the AtEXPA5 gene was reduced most by exogenous ethylene. 2-Aminoethoxyvinylglycine, an ethylene biosynthesis inhibitor, increased AtEXPA5 transcription. Ethylene insensitive (ein7) and constitutive (ctr1) mutants resulted in increased and decreased transcription, respectively, thereby suggesting that ethylene endogenously downregulates AtEXPA5 expression. Hypocotyl elongation followed the same trend as AtEXPA5 expression, implying that changes in hypocotyl elongation reflect changes in AtEXPA5 expression. A transgenic plant line that overexpresses AtEXPA5, 35S-EXPA5, showed a reduced response to exogenous ethylene in terms of hypocotyl lengths when compared to wild-type and expA5-1, a knockout mutant. These results and the dose-dependent effect of aminocyclopropane-1-carboxyl acid on hypocotyl elongation implicate AtEXPA5 overexpression in making tissues more sensitive to high doses of ethylene. In summary, AtEXPA5 appears to respond to ethylene and play a role in ethylene regulating hypocotyl elongation in Arabidopsis thaliana.

Endogenous level of abscisic acid down-regulated by brassinosteroids signaling via BZR1 to control the growth of Arabidopsis thaliana.

The increased level of endogenous abscisic acid (ABA) in brassinosteroid (BR)-deficient mutants, such as det2 and cyp85a1 × cyp85a2, suggests that ABA synthesis is inhibited by endogenous BRs in Arabidopsis thaliana. Expression of the ABA biosynthesis gene ABA-deficient 2 (ABA2) was negatively regulated by exogenously applied BR but up-regulated by the application of brassinazole and in det2 and cyp85a1 × cyp85a2. In addition, ABA2 expression decreased in bzr1-1D, showing that ABA biosynthesis is inhibited by BR signaling via BZR1, intermediated by ABA2, in Arabidopsis. Four cis-element sequences (E-boxes 1-4) in the putative promoter region of ABA2 were identified as BZR1 binding sites. The electrophoretic mobility shift assay and chromatin immune precipitation analysis demonstrated that BZR1 directly binds to overlapped E-boxes (E-box 3/4) in the promoter region of ABA2. The level of endogenous ABA was decreased in bzr1-1D compared to wild-type, indicating that binding of BZR1 to the ABA2 promoter inhibits ABA synthesis in Arabidopsis. Compared to wild-type, aba2-1 exhibited severely reduced growth and development. The abnormalities in aba2-1 were rescued by the application of ABA, suggesting that ABA2 expression and ABA synthesis are necessary for the normal growth and development of A. thaliana. Finally, bzr1-KO × aba2-1 exhibited inhibitory growth of primary roots compared to bzr1-KO, verifying that ABA2 is a downstream target of BZR1 in the plant. Taken together, the level of endogenous ABA is down-regulated by BR signaling via BZR1, controlling the growth of A. thaliana.

Brassinosteroids signaling via BZR1 down-regulates expression of ACC oxidase 4 to control growth of Arabidopsis thaliana seedlings.

ProACO4-GUS expression and RT-PCR analysis revealed that ACO4 is predominantly expressed in shoots of Arabidopsis seedlings under light conditions. ACO4-overexpressed mutant 35S-ACO4 produced more ethylene relative to the wild-type, which resulted in reduced growth of Arabidopsis seedlings. The abnormal growth of seedlings recurred after the application of Co2+ ions, suggesting that ACO4 is a functional ACO necessary to regulate the growth and development of Arabidopsis seedlings. Exogenously-applied brassinosteroids (BRs) inhibited the expression of ACO4, and an enhanced ACO4 expression was found in det2, a BR-deficient mutant. Additionally, expression of ACO4 was decreased in bzr1-D (a BZR1-dominant mutant), implying that BR signaling negatively regulates ACO4 expression via BZR1 in Arabidopsis. In the intergenic region of ACO4, four E-boxes and a BR regulatory element (BRRE) are found. Electrophoretic mobility shift and chromatin immunoprecipitation assays showed that BZR1 binds directly to the BRRE in the putative promoter region of ACO4. By binding of BZR1 to BRRE, less ethylene was produced, which seems to regulate the growth and development of Arabidopsis seedlings.

Early-Phase 18F-Florbetaben PET as an Alternative Modality for 18F-FDG PET.

PURPOSE: Based on the possibility that early-phase florbetaben (E-FBB) brain PET can be a surrogate for brain perfusion imaging, we conducted this study to investigate the clinical utility of E-FBB PET instead of F-FDG brain PET. MATERIALS AND METHODS: This prospective study included 35 patients with clinical suspicion of cognitive decline or dementia and 5 healthy controls. Brain MRI, E-FBB PET, late-phase FBB PET, and FDG PET were acquired. The regional SUV ratios (SUVRs) were calculated by cortical surface region of interest analysis using individual MRI, and relationship between E-FBB and FDG PET was analyzed. All PET scans were scored and analyzed as per visual scoring system, which represent tracer uptake abnormality. Moreover, uptake patterns were analyzed to determine the disease. RESULTS: Among the 40 subjects, 19 were amyloid-positive and 21 were amyloid-negative on late-phase FBB PET. Cortical surface region of interest analysis conducted for comparing between E-FBB and FDG PET revealed significant correlations (P < 0.0001) for regional SUVR among all brain regions; however, the SUVR values of FDG PET were statistically higher than those of E-FBB PET. Similarly, although the visually rated scores for E-FBB and FDG PET showed significant correlation (P < 0.0001), it was considered that the tracer uptake was more severely decreased for FDG PET. The disease types, specified by E-FBB and FDG PET, were statistically correlated. CONCLUSIONS: E-FBB PET could potentially be a useful biomarker for the diagnosis of dementia in place of FDG PET. Nevertheless, the severity of the disease was more accurately determined by FDG PET.

Correction: A new bioluminescent reporter system to study the biodistribution of systematically injected tumor-derived bioluminescent extracellular vesicles in mice.

[This corrects the article DOI: 10.18632/oncotarget.22493.].