Genome-Wide Identification and Characterization of the PP2C Family from Zea mays and Its Role in Long-Distance Signaling.

The protein phosphatase 2C (PP2C) constitutes a large gene family that plays crucial roles in regulating stress responses and plant development. A recent study has shown the involvement of an AtPP2C family member in long-distance nitrogen signaling in Arabidopsis. However, it remains unclear whether maize adopts a similar mechanism. In this study, we conducted a genome-wide survey and expression analysis of the PP2C family in maize. We identified 103 ZmPP2C genes distributed across 10 chromosomes, which were further classified into 11 subgroups based on an evolutionary tree. Notably, cis-acting element analysis revealed the presence of abundant hormone and stress-related, as well as nitrogen-related, cis-elements in the promoter regions of ZmPP2Cs. Expression analysis demonstrated the distinct expression patterns of nine genes under two nitrogen treatments. Notably, the expression of ZmPP2C54 and ZmPP2C85 in the roots was found to be regulated by long-distance signals from the shoots. These findings provide valuable insights into understanding the roles of ZmPP2Cs in long-distance nitrogen signaling in maize.

[Cloning and functional characterization of a lysophosphatidic acid acyltransferase gene from Perilla frutescens].

Perilla (Perilla frutescens L.) is an important edible-medicinal oil crop, with its seed containing 46%-58% oil. Of perilla seed oil, α-linolenic acid (C18:3) accounts for more than 60%. Lysophosphatidic acid acyltransferase (LPAT) is one of the key enzymes responsible for triacylglycerol assembly in plant seeds, controlling the metabolic flow from lysophosphatidic acid to phosphatidic acid. In this study, the LPAT2 gene from the developing seeds of perilla was cloned and designated as PfLPAT2. The expression profile of PfLPAT2 gene was examined in various tissues and different seed development stages of perilla (10, 20, 30, and 40 days after flowering, DAF) by quantitative real-time PCR (qRT-PCR). In order to detect the subcellular localization of PfLPAT2 protein, a fusion expression vector containing PfLPAT2 and GFP was constructed and transformed into Nicotiana benthamiana leaves by Agrobacterium-mediated infiltration. In order to explore the enzymatic activity and biological function of PfLPAT2 protein, an E. coli expression vector, a yeast expression vector and a constitutive plant overexpression vector were constructed and transformed into an E. coli mutant SM2-1, a wild-type Saccharomyces cerevisiae strain INVSc1, and a common tobacco (Nicotiana tabacum, variety: Sumsun NN, SNN), respectively. The results showed that the PfLPAT2 open reading frame (ORF) sequence was 1 155 bp in length, encoding 384 amino acid residues. Functional structure domain prediction showed that PfLPAT2 protein has a typical conserved domain of lysophosphatidic acid acyltransferase. qRT-PCR analysis indicated that PfLPAT2 gene was expressed in all tissues tested, with the peak level in seed of 20 DAF of perilla. Subcellular localization prediction showed that PfLPAT2 protein is localized in cytoplasm. Functional complementation assay of PfLPAT2 in E. coli LPAAT mutant (SM2-1) showed that PfLPAT2 could restore the lipid biosynthesis of SM2-1 cell membrane and possess LPAT enzyme activity. The total oil content in the PfLPAT2 transgenic yeast was significantly increased, and the content of each fatty acid component changed compared with that of the non-transgenic control strain. Particularly, oleic acid (C18:1) in the transgenic yeast significantly increased, indicating that PfLPAT2 has a higher substrate preference for C18:1. Importantly, total fatty acid content in the transgenic tobacco leaves increased by about 0.42 times compared to that of the controls, with the C18:1 content doubled. The increased total oil content and the altered fatty acid composition in transgenic tobacco lines demonstrated that the heterologous expression of PfLPAT2 could promote host oil biosynthesis and the accumulation of health-promoting fatty acids (C18:1 and C18:3). This study will provide a theoretical basis and genetic elements for in-depth analysis of the molecular regulation mechanism of perilla oil, especially the synthesis of unsaturated fatty acids, which is beneficial to the genetic improvement of oil quality of oil crops.

[Overexpression of NtAGPase small subunit gene increases leaf starch content and tobacco biomass].

Production of biofuels such as ethanol from non-grain crops may contribute to alleviating the global energy crisis and reducing the potential threat to food security. Tobacco (Nicotiana tabacum) is a commercial crop with high biomass yield. Breeding of starch-rich tobacco plants may provide alternative raw materials for the production of fuel ethanol. We cloned the small subunit gene NtSSU of ADP-glucose pyrophosphorylase (NtAGPase), which controls starch biosynthesis in tobacco, and constructed a plant expression vector pCAMBIA1303-NtSSU. The NtSSU gene was overexpressed in tobacco upon Agrobacterium-mediated leaf disc transformation. Phenotypic analysis showed that overexpression of NtSSU gene promoted the accumulation of starch in tobacco leaves, and the content of starch in tobacco leaves increased from 17.5% to 41.7%. The growth rate and biomass yield of the transgenic tobacco with NtSSU gene were also significantly increased. The results revealed that overexpression of NtSSU gene could effectively redirect more photosynthesis carbon flux into starch biosynthesis pathway, which led to an increased biomass yield but did not generate negative effects on other agronomic traits. Therefore, NtSSU gene can be used as an excellent target gene in plant breeding to enrich starch accumulation in vegetative organs to develop new germplasm dedicated to fuel ethanol production.

Astaxanthin from Haematococcus pluvialis alleviates obesity by modulating lipid metabolism and gut microbiota in mice fed a high-fat diet.

Obesity is a global chronic disease epidemic that is attributed to the abnormal accumulation of lipids in adipose tissue. Astaxanthin (AST) from Haematococcus pluvialis, a natural carotenoid, exhibits antioxidant, anti-lipogenic, anti-diabetic and other potent effects. Herein, we evaluated the effect of AST to illuminate its efficacy and mechanisms in high-fat diet-fed mice. AST supplementation not only significantly decreased body weight and lipid droplet accumulation in the liver but also modulated liver function and serum lipid levels. Lipidomic analysis revealed that 13 lipids might be potential biomarkers responsible for the effects of AST in lipid reduction, such as total free fatty acids (FFAs), triacylglycerols (TGs) and cholesterol esters (CEs). The gut microbiota sequencing results indicated that AST alleviated HFD-induced gut microbiota dysbiosis by optimizing the ratio of Firmicutes to Bacteroides and inhibiting the abundance of obesity-related pathogenic microbiota while promoting the abundance of probiotics related to glucose and lipid metabolism. In addition, qRT-PCR demonstrated that AST could regulate the gene expressions of the AMPK/SREBP1c pathway by downregulating lipogenesis correlated-genes and upregulating the lipid oxidant related-gene. The present study revealed the new function of AST in regulating lipid metabolism, which provided a theoretical basis for the development of high-quality AST functional food and the application of diet active substances in obesity, as demonstrated in mice.

Discovery of STAT3 and Histone Deacetylase (HDAC) Dual-Pathway Inhibitors for the Treatment of Solid Cancer.

Nowadays, simultaneous inhibition of multiple targets through drug combination is an important anticancer strategy owing to the complex mechanism behind tumorigenesis. Recent studies have demonstrated that the inhibition of histone deacetylases (HDACs) will lead to compensated activation of a notorious cancer-related drug target, signal transducer and activator of transcription 3 (STAT3), in breast cancer through a cascade, which probably limits the anti-proliferation effect of HDAC inhibitors in solid tumors. By incorporating the pharmacophore of the HDAC inhibitor SAHA (vorinostat) into the STAT3 inhibitor pterostilbene, a series of potent pterostilbene hydroxamic acid derivatives with dual-target inhibition activity were synthesized. An excellent hydroxamate derivate, compound 14, inhibited STAT3 (KD = 33 nM) and HDAC (IC50 = 23.15 nM) with robust potency in vitro. Compound 14 also showed potent anti-proliferation ability in vivo and in vitro. Our study provides the first STAT3 and HDAC dual-target inhibitor for further exploration.

Discovery of bazedoxifene analogues targeting glycoprotein 130.

Deregulation of GP130 in signal transduction is involved in multiple types of human diseases, especially in cancers, indicating that GP130 is an attractive target for cancer therapy. However, GP130 was conventionally considered as an undruggable target thus the discovery of GP130 PPI inhibitors is extremely challenging. By the aid of structure-based drug design, in this study, two series of bazedoxifene based analogues were designed to target GP130 D1 domain and block the IL-6/GP130/STAT3 signaling pathway for antitumor treatment. Most of these designed compounds displayed potent anti-proliferative activity against cancer cells. The representative compound 10a was demonstrated to directly bind to GP130 protein with an affinity (KD) value of 3.8 µM via both SPR and DARTS methods. Subsequently, molecular docking study predicted that 10a targeted D1 domain of GP130 and co-IP assay demonstrated that 10a did not inhibit IL-6R/GP130 interaction, which meant 10a did not bind to the D2 and D3 domains of GP130. Moreover, 10a selectively inhibited JAK2 and STAT3 phosphorylation as well as IL-6 induced STAT3 phosphorylation. 10a effectively inhibited tumor cell viability, migration and promoted apoptosis. Furthermore, 10a effectively suppressed xenograft model tumor growth in vivo. Taken together, this study described a new class of bazedoxifene derived GP130 inhibitors as antitumor agents.

Real-time monitoring of etoposide prodrug activated by hydrogen peroxide with improved safety.

Etoposide is one of the most used first-line chemotherapeutic drugs. However, its application is still limited by its side effects. Herein, we designed a novel H2O2 sensitive prodrug 6YT for selectively releasing the anti-cancer drug etoposide in cancer cells. In this paper, etoposide and a hydrogen peroxide (H2O2) sensitive aryl borate ester group were linked by a fluorescent coumarin and finally the prodrug 6YT was generated. The fluorescence of coumarin was quenched before the connected aryl borate ester group was cleaved by H2O2. However, in the high level H2O2 environment of the tumor, the fluorescence could be activated simultaneously with the release of etoposide, and the drug release state of the prodrug was monitored real-time. With the support of 6YT, we obtained direct and visual evidence of etoposide release in a high H2O2 environment both in cells and zebrafish. The prodrug 6YT was also verified with comparable activity and improved safety with etoposide both in cells and in a mouse model. As a safe and effective prodrug, 6YT is expected to be one of the promising candidates in chemotherapy against cancer.

Discovery of fluorescent coumarin-benzo[b]thiophene 1, 1-dioxide conjugates as mitochondria-targeting antitumor STAT3 inhibitors.

STAT3 has been extensively studied as a potential antitumor target. Though studies on regulating STAT3 mainly focus on the inhibition of STAT3 phosphorylation at Tyr705 residue, the phosphorylation at Ser727 residue of STAT3 protein is also closely associated with the mitochondrial import of STAT3 protein. N, N-diethyl-7-aminocoumarin is a fluorescent mitochondria-targeting probe. In this study, a series of STAT3 inhibitors were developed by connecting N, N-diethyl-7-aminocoumarin fluorophore with benzo [b]thiophene 1, 1-dioxide moiety. All designed compounds displayed potent anti-proliferative activity against cancer cells. The representative compound 7a was mainly accumulated in mitochondria visualized by its fluorescence. STAT3 phosphorylation was inhibited by compound 7a at both Tyr705 and Ser727 residues. Compound 7a inhibited STAT3 phosphorylation whereas had no influence on the phosphorylation levels of STAT1, JAK2, Src and Erk1/2, indicating good selectivity of compound 7a. Moreover, compound 7a down-regulated the expression of STAT3 target genes Bcl-2 and Cyclin D1, increased ROS production and remarkably reduced the mitochondrial membrane potential to induce mitochondrial apoptotic pathway. Furthermore, compound 7ain vivo suppressed breast cancer 4T1 implanted tumor growth. Taken together, these results highlighted that compound 7a might be a promising mitochondria-targeting STAT3 inhibitor for cancer therapy.

Discovery of new benzensulfonamide derivatives as tripedal STAT3 inhibitors.

Persistent activated STAT3 has a striking correlation with cancer development and inhibition of STAT3 signaling pathway is a novel therapeutic way for human cancers. Among STAT family, STAT1 and STAT3 play opposite roles in tumorigenesis. However, the discovery of selective STAT3 inhibitors is still challenging to date. In this study, a series of small-molecular (MW < 500) benzensulfanilamide derivatives were designed to selectively suppress STAT3 activation for anti-cancer treatment. The most potent compound 11 inhibited both overexpressed and IL-6 induced STAT3 phosphorylation, whereas 11 displayed little effect on the phosphorylation of other STAT isoforms STAT1, STAT5, demonstrating 11 was a selective STAT3 inhibitor. Meanwhile, 11 dismissed STAT3 DNA binding activity and colony formation. In addition, 11 elevated the ROS level and induced apoptosis of cancer cells. Furthermore, 11 effectively suppressed tumor growth in an in vivo mouse-xenograft model.

A new synthetic derivative of cryptotanshinone KYZ3 as STAT3 inhibitor for triple-negative breast cancer therapy.

Silencing STAT3 is confirmed as a promising therapeutic strategy for triple-negative breast cancer (TNBC) therapy to address the issue of its poor prognosis. In this study, the natural product cryptotanshinone was firstly remodeled and modified as a more effective STAT3 inhibitor by structure-based strategy. The synthetic derivative KYZ3 had 22-24-fold increase in antitumor activity than cryptotanshinone on two TNBC cell lines but had little effect on normal breast epithelial MCF-10A cells. Further investigation showed that KYZ3 inhibited persistent STAT3 phosphorylation. It also prevented the STAT3 protein nuclear translocation to regulate the expressions of the target oncogenes including Bax and Bcl-2. Furthermore, KYZ3 inhibited TNBC cell metastasis by decreasing the levels of MMP-9 which were directly regulated by activated STAT3. A STAT3 plasmid transfecting assay suggested that KYZ3 induced tumor cell apoptosis mainly by targeting STAT3. Finally, KYZ3 suppressed the growth of tumors resulting from subcutaneous implantation of MDA-MB-231 cells in vivo. Taken together, KYZ3 may be a promising cancer therapeutic agent for TNBC.

[Diagnostic value and clinical application of CT/HRCT for coal workers' pneumoconiosis with large opacities].

OBJECTIVE: To study the diagnostic value of CT/HRCT for the coal workers' pneumoconiosis (CWP) with large opacities. METHODS: Sixty-two patients with CWP were examined with both chest radiograph and CT/HRCT scan. Comparison was done. RESULTS: Large opacities were found in 19 patients in the chest radiograph of 62 patients with CWP. The detection rate was 30.6%. Thirty large opacities were found using chest radiograph. Forty-three patients with large opacities were found using the CT/HRCT. The detection rate was 69.4%. One hundred and twenty-three large opacities were found using CT/HRCT. Ninety-three more large opacities were found by CT/HRCT than by chest radiograph. The total detection rate of large opacities by CT was 4.1 times than by chest radiograph. Both differences were statistically significant (chi2 = 18.58, P < 0.01). CT/HRCT found all patients with large opacities detected in the chest radiograph. Seventeen patients with Stage III large opacities (>or= 1.0 cm x 2.0 cm) were found by the chest radiograph. The detection rate was 27.4% (17/62). Twenty-seven large opacities were found using chest radiograph. Thirty-four patients with Stage III large opacities were found using the CT/HRCT. The detection rate was 54.8%. The found Stage III large opacities added up to 67. The found Stage III large opacities by CT/HRCT were 40 more than using chest radiograph. Both differences were statistically significant (chi2 = 9.63, P < 0.01). CT/HRCT was reliable to show the morphology, the inside structure, the tiny lesion and the special location of the large opacities of CWP. It could provide more important information for differential diagnosis. CONCLUSION: CT/HRCT is significantly better than the chest radiograph in the diagnosis of complicated CWP. It can find the large opacities that the chest radiograph can not. It has a great diagnostic and practical value as an assistant examination method. CT/HRCT could be considered as the reference and evidence for staging progression in diagnosis of pneumoconiosis.

[CT quantitative study of coal miner's pneumoconiosis].

OBJECTIVE: To study the value of CT quantitativeness in the diagnosis of coal miner's pneumoconiosis. METHODS: 104 cases were examined by HRCT scan at top of aortic arc, carina of trachea, 3 cm below the bifurcation of bronchi, among them there were 87 patients with different stages of coal miner's pneumoconiosis, 17 cases of normal males as the control group. All images were determined by CT density histogram at specific region (- 1,024-0 HU). Calculated the percentage of each pixel included a varying number of CT value, and the ratio of density values in the specific region. RESULTS: The ratio of density values in the region of -983 (-) -778 HU was 87.31% in normal control group, and 80.51%, 75.27% and 72.99% respectively in the I, II, III stages of coal miner's pneumoconiosis. There were statistically significant differences among the groups (P < 0.01). CONCLUSION: CT quantitative histogram information was able to observe the fibrosis and its degree of coal miner's pneumoconiosis. It has a good diagnostic value for its reliability and objectiveness.

[The diagnostic value and morphologic manifestation of high resolution computerized tomography in coal miner's pneumoconiosis with pleural pathological changes].

OBJECTIVE: To analyse CT and high resolution computerized tomography (HRCT) diagnostic value and morphologic manifestation in coal miner's pneumoconiosis with pleural pathological changes. METHODS: One hundred and thirty-one cases of coal miner patients with pneumoconiosis (0(+) type: 14 cases, type I: 46 cases, type II: 58 cases, type III: 13 cases) and 20 normal people as control group were first examined by routine CT scan at 4 fixed slices, followed by HRCT examination at the region of interest (ROI). Meanwhile, all of them had high-kV chest radiography. RESULTS: According to the national standard of the People's Republic of China in the diagnosis of coal miner's pneumoconiosis with pleural plaque, 68 cases of pleural disease making up 51.91% (68/131) were found (type I accounted for 17.65%, type II 63.24%, type III 19.12%). The morphologic manifestation of pleural pathology by HRCT could be classified into four types: (1) nodular type: 73.38%, (2) flat type: 18.71%, (3) irregular type: 7.91%, (4) mixed type. The pleural pathological changes were found in thoracic wall pleura (65.02%), surface of mediastinum (22.16%), and pericardium (12.80%), but not found in the top of lung and costo-phrenic angles. The thickness of pleura was often about 5 approximately 10 mm (88.17%). CONCLUSION: Pleural pathological changes were not seldom seen in coal miner's pneumoconiosis. HRCT is a reliable examination method aiding routine CT to show pleural pathological changes, thus it has a great diagnostic and practical value. It is necessary to make a further comparison study between pathology and imagology.