Correlation of related indexes of blood lipid and insulin resistance with cognition scores in middle-aged and elderly people with mild cognitive impairment / 中华健康管理学杂志

Objective:To analyze the correlation between related indexes of serum lipid and insulin resistance and cognitive impairment in middle-aged and elderly people with mild cognitive impairment (MCI).Methods:In this cross-sectional study, 262 middle-aged and elderly patients with a Montreal Cognitive Function Scale (MoCA) cognitive score greater than or equal to 18 points who underwent physical examination in the Health Management Center of Beijing Tiantan Hospital Affiliated to Capital Medical University from January 1 to July 31, 2021 were selected as subjects. According to the cognitive function and MoCA score, the patients were divided into MCI group (143 cases) and normal cognition group (119 cases). Basic data, fasting blood glucose, triglyceride (TG), total cholesterol, apolipoprotein E(ApoE) genotype and other clinical indicators were collected. Hypothesis test was used to compare the differences in basic data, related indicators of blood lipid and insulin resistance between the two groups. Spearman correlation analysis was used to analyze the correlation between related indicators of blood lipid and insulin resistance and MoCA score in the two groups.Results:The age and the proportion of patients with hypertension, coronary heart disease and diabetes in the MCI group were all significantly higher than those in normal cognition group [(54.83±8.29) vs (50.76±6.34) years, 37.76% vs 31.93%, 4.20% vs 0.84%, 16.08% vs 8.40%] (all P<0.05). The elevation of serum TG ( r=-0.50, 95% CI:-0.88--0.12), TG glucose product index (TyG) ( r=-0.75, 95% CI:-1.29--0.20) and TG to high-density lipoprotein cholesterol ratio (TG/HDL-C) ( r=-0.52, 95% CI:-0.91--0.13) were all negatively correlated with MoCA score (all P<0.05). After adjusting for age and gender, the elevation of TG ( r=-0.39, 95% CI:-0.75--0.31) and TG/HDL-C ( r=-0.43, 95% CI:-0.80--0.05) were both still negatively correlated with MoCA score (both P<0.05). There was no significant correlation between all indexes and MoCA scores in the normal cognition group (all P>0.05). The elevated TG was negatively correlated with MoCA score in the MCI group ( r=-0.70, 95% CI:-1.23-0.16, P=0.017). There was no significant correlation between elevated TG and MoCA score in patients carrying ApoE ε2 and ApoE ε3 genotypes in MCI group (all P>0.05). Conclusion:Elevated related indexes of blood lipids and insulin resistance are negatively correlated with cognitive scores in middle-aged and elderly people with MCI, and it′s more obvious in patients with ApoE ε4 genotype.

Biological fate and interaction with cytochromes P450 of the nanocarrier material, d-α-tocopheryl polyethylene glycol 1000 succinate

d-α-Tocopheryl polyethylene glycol 1000 succinate (TPGS, also known as vitamin E-TPGS) is a biodegradable amphiphilic polymer prepared by esterification of vitamin E with polyethylene glycol (PEG) 1000. It is approved by the US Food and Drug Administration (FDA) and has found wide application in nanocarrier drug delivery systems (NDDS). Fully characterizing the in vivo fate and pharmacokinetic behavior of TPGS is important to promote the further development of TPGS-based NDDS. However, to date, a bioassay for the simultaneous quantitation of TPGS and its metabolite, PEG1000, has not been reported. In the present study, we developed such an innovative bioassay and used it to investigate the pharmacokinetics, tissue distribution and excretion of TPGS and PEG1000 in rat after oral and intravenous dosing. In addition, we evaluated the interaction of TPGS with cytochromes P450 (CYP450s) in human liver microsomes. The results show that TPGS is poorly absorbed after oral administration with very low bioavailability and that, after intravenous administration, TPGS and PEG1000 are mainly distributed to the spleen, liver, lung and kidney before both being slowly eliminated in urine and feces as PEG1000. In vitro studies show the inhibition of human CYP450 enzymes by TPGS is limited to a weak inhibition of CYP3A4. Overall, our results provide a clear picture of the in vivo fate of TPGS which will be useful in evaluating the safety of TPGS-based NDDS in clinical use and in promoting their further development.

Identification and expression analysis of WRKY gene family in eukaryotic algae / 生物工程学报

WRKY is a superfamily of plant-specific transcription factors, playing a critical regulatory role in multiple biological processes such as plant growth and development, metabolism, and responses to biotic and abiotic stresses. Although WRKY genes have been characterized in a variety of higher plants, little is known about them in eukaryotic algae, which are close to higher plants in evolution. To fully characterize algal WRKY family members, we carried out multiple sequence alignment, phylogenetic analysis, and conserved domain prediction to identify the WRKY genes in the genomes of 30 algal species. A total of 24 WRKY members were identified in Chlorophyta, whereas no WRKY member was detected in Rhodophyta, Glaucophyta, or Bacillariophyta. The 24 WRKY members were classified into Ⅰ, Ⅱa, Ⅱb and R groups, with a conserved heptapeptide domain WRKYGQ(E/A/H/N)K and a zinc finger motif C-X4-5-C-X22-23-H-X-H. Haematococcus pluvialis, a high producer of natural astaxanthin, contained two WRKY members (HaeWRKY-1 and HaeWRKY-2). Furthermore, the coding sequences of HaeWRKY-1 and HaeWRKY-2 genes were cloned and then inserted into prokaryotic expression vector. The recombinant vectors were induced to express in Escherichia coli BL21(DE3) cells and the fusion proteins were purified by Ni-NTA affinity chromatography. HaeWRKY-1 had significantly higher expression level than HaeWRKY-2 in H. pluvialis cultured under normal conditions. High light stress significantly up-regulated the expression of HaeWRKY-1 while down-regulated that of HaeWRKY-2. The promoters of HaeWRKY genes contained multiple cis-elements responsive to light, ethylene, ABA, and stresses. Particularly, the promoter of HaeWRKY-2 contained no W-box specific for WRKY binding. However, the W-box was detected in the promoters of HaeWRKY-1 and the key enzyme genes HaeBKT (β-carotene ketolase) and HaePSY (phytoene synthase) responsible for astaxanthin biosynthesis. Considering these findings and the research progress in the related fields, we hypothesized that the low expression of HaeWRKY-2 under high light stress may lead to the up-regulation of HaeWRKY-1 expression. HaeWRKY-1 may then up-regulate the expression of the key genes (HaeBKT, HaePSY, etc.) for astaxanthin biosynthesis, consequently promoting astaxanthin enrichment in algal cells. The findings provide new insights into further analysis of the regulatory mechanism of astaxanthin biosynthesis and high light stress response of H. pluvialis.

Overexpression of NtAGPase small subunit gene increases leaf starch content and tobacco biomass / 生物工程学报

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.

Transcriptome analysis of signal transduction pathway involved in light inducing astaxanthin accumulation in Haematococcus pluvialis / 生物工程学报

The unicellular green alga Haematococcus pluvialis is the best source of natural astaxanthin (AST) in the world due to its high content under stress conditions. Although high light (HL) can effectively induce AST biosynthesis, the specific mechanisms of light signal perception and transduction are unclear. In the current study, we used transcriptomic data of normal (N), high white light (W), and high blue light (B) to study the mechanisms of light inducing AST accumulation from the point of photoreceptors. The original data of 4.0 G, 3.8 G, and 3.6 G for N, W, and B were obtained, respectively, by the Illumina Hi-seq 2000 sequencing technology. Totally, 51 954 unigenes (at least 200 bp in length) were generated, of which, 20 537 unigenes were annotated into at least one database (NR, NT, KO, SwissProt, Pfam, GO, or KOG). There were 1 255 DEGs in the W vs N, 1 494 DEGs in the B vs N, and 1 008 DEGs in the both W vs N and B vs N. KEGG enrichment analysis revealed that photosynthesis, oxidative phosphorylation, carotenoid biosynthesis, fatty acids biosynthesis, DNA replication, nitrogen metabolism, and carbon metabolism were the significantly enriched pathways. Moreover, a large number of genes encoding photoreceptors and predicted interacting proteins were predicted in Haematococcus transcriptome data. These genes showed significant differences at transcriptional expression levels. In addition, 15 related DEGs were selected and tested by qRT-PCR and the results were significantly correlated with the transcriptome data. The above results indicate that the signal transduction pathway of "light signal - photoreceptors - interaction proteins - (interaction proteins - transcription factor/transcriptional regulator) - gene expression - AST accumulation" might play important roles in the regulation process, and provide reference for further understanding the transcriptional regulation mechanisms of AST accumulation under HL stress.

Identification and functional analysis of soybean stearoyl-ACP Δ⁹ desaturase (GmSAD) gene family / 生物工程学报

Stearoyl-ACP Δ⁹ desaturase (SAD) catalyzes the synthesis of monounsaturated oleic acid or palmitoleic acid in plastids. SAD is the key enzyme to control the ratio of saturated fatty acids to unsaturated fatty acids in plant cells. In order to analyze the regulation mechanism of soybean oleic acid synthesis, soybean (Glycine max) GmSAD family members were genome-wide identified, and their conserved functional domains and physicochemical properties were also analyzed by bioinformatics tools. The spatiotemporal expression profile of each member of GmSADs was detected by qRT-PCR. The expression vectors of GmSAD5 were constructed. The enzyme activity and biological function of GmSAD5 were examined by Agrobacterium-mediated transient expression in Nicotiana tabacum leaves and genetic transformation of oleic acid-deficient yeast (Saccharomyces cerevisiae) mutant BY4389. Results show that the soybean genome contains five GmSAD family members, all encoding an enzyme protein with diiron center and two conservative histidine enrichment motifs (EENRHG and DEKRHE) specific to SAD enzymes. The active enzyme protein was predicted as a homodimer. Phylogenetic analysis indicated that five GmSADs were divided into two subgroups, which were closely related to AtSSI2 and AtSAD6, respectively. The expression profiles of GmSAD members were significantly different in soybean roots, stems, leaves, flowers, and seeds at different developmental stages. Among them, GmSAD5 expressed highly in the middle and late stages of developmental seeds, which coincided with the oil accumulation period. Transient expression of GmSAD5 in tobacco leaves increased the oleic acid and total oil content in leaf tissue by 5.56% and 2.73%, respectively, while stearic acid content was reduced by 2.46%. Functional complementation assay in defective yeast strain BY4389 demonstrated that overexpression of GmSAD5 was able to restore the synthesis of monounsaturated oleic acid, resulting in high oil accumulation. Taken together, soybean GmSAD5 has strong selectivity to stearic acid substrates and can efficiently catalyze the biosynthesis of monounsaturated oleic acid. It lays the foundation for the study of soybean seed oleic acid and total oil accumulation mechanism, providing an excellent target for genetic improvement of oil quality in soybean.

Seed-specific expression of heterologous gene DGAT1 increase soybean seed oil content and nutritional quality / 生物工程学报

Enhancing soybean (Glycine max) oil production is crucial to meet the market demand of vegetable oil. Diacylglycerol acyltransferase (DGAT) catalyzes the final acylation reaction of triacylglycerol (TAG) synthesis, acting as one of the rate-limiting enzymes for oil biosynthesis in plant seeds. Here, a cDNA clone VgDGAT1A encoding the DGAT1 protein was isolated from the high oil plant Vernonia galamensis. VgDGAT1A was specifically overexpressed in soybean seeds, and several high-generation transgenic lines (T7) were obtained by continuous selection. qPCR analysis showed that VgDGAT1A was highly expressed in the mid-development stage (30-45 DAF) of the transgenic seeds. Accordingly, the DGAT enzyme activity in the transgenic seeds was increased by 7.8 folds in comparison with the wild-type controls. Seed oil and starch contents were, respectively, increased by 5.1% (Dry weight) and reduced by 2%-3% in the transgenic soybeans. Importantly, protein content was not significantly different between transgenic and control seeds. Seed weight and germination rate of the transgenic lines exhibited no negative effect. Fatty acid profiling demonstrated that antioxidant oleic acid (C18:1Δ9) content in the transgenic seed oil was elevated by 8.2% compared to the control, and correspondingly, easily-oxidized linoleic acid (C18:2Δ9,12) and linolenic acid (C18:3Δ9,12,15) were decreased by 6% and 2% respectively. Taken together, seed-specific overexpression of an exogenous VgDGAT1A gene can break the negative linkage of oil and protein contents in soybean seeds, indicating that engineering of this highly-active DGAT enzyme is an effective strategy to improve oil yield and nutritional value in oilseeds.

Expression of yeast acyl-delta9 desaturase for fatty acid biosynthesis in tobacco / 生物工程学报

Palmitoleic acid (16:1delta9), an unusual monounsaturated fatty acid, is highly valued for human nutrition, medication and industry. Plant oils containing large amounts of palmitoleic acid are the ideal resource for biodiesel production. To increase accumulation of palmitoleic acid in plant tissues, we used a yeast (Saccharomyees cerevisiae) acyl-CoA-delta9 desaturase (Scdelta9D) for cytosol- and plastid-targeting expression in tobacco (Nicotiana tabacum L.). By doing this, we also studied the effects of the subcellular-targeted expression of this enzyme on lipid synthesis and metabolism in plant system. Compared to the wild type and vector control plants, the contents of monounsaturated palmitoleic (16:1delta9) and cis-vaccenic (18:1delta11) were significantly enhanced in the Scdelta9D-transgenic leaves whereas the levels of saturated palmitic acid (16:0) and polyunsaturated linoleic (18:2) and linolenic (18:3) acids were reduced in the transgenics. Notably, the contents of 16:1delta9 and 18:1delta11 in the Scdelta9D plastidal-expressed leaves were 2.7 and 1.9 folds of that in the cytosolic-expressed tissues. Statistical analysis appeared a negative correlation coefficient between 16:0 and 16:1delta9 levels. Our data indicate that yeast cytosolic acyl-CoA-delta9 desaturase can convert palmitic (16:0) into palmitoleic acid (16:1delta9) in high plant cells. Moreover, this effect of the enzyme is stronger with the plastid-targeted expression than the cytosol-target expression. The present study developed a new strategy for high accumulation of omega-7 fatty acids (16:1delta9 andl8:1delta11) in plant tissues by protein engineering of acyl-CoA-delta9 desaturase. The findings would particularly benefit the metabolic assembly of the lipid biosynthesis pathway in the large-biomass vegetative organs such as tobacco leaves for the production of high-quality biodiesel.

Identification and expression analysis of WRKY transcription factors in medicinal plant Catharanthus roseus / 生物工程学报

WRKY transcription factors, one of the largest families of transcriptional regulators in plants, involve in multiple life activities including plant growth and development as well as stress responses. However, little is known about the types and functions of WRKY transcription factors in Catharanthus roseus, an important medicinal plant. In this study, we identified 47 CrWRKY transcriptional factors from 26 009 proteins in Catharanthus roseus, and classified them into three distinct groups (G1, G2 and G3) according to the structure of WRKY domain and evolution of the protein family. The expression profiling showed that these CrWRKY genes expressed in a tissue/organ specific manner. The 47 CrWRKY genes were clustered into three types of expression patterns. The first type includes the CrWRKYs highly expressed in flowers and the protoplast treated with methy jasmonate (MeJA) or yeast extraction (YE). The second type contains the CrWRKYs highly expressed in stem and hairy root. The third type represents the CrWRKYs highly expressed in root, stem, leaf, seedling and the hairy root treated by MeJA. Real time quantitative PCR was employed to further identify the expression patterns of the 16 selected CrWRKY genes in various organs, the MeJA-treated protoplasts and hairy roots of Catharanthus roseus, and similar results were obtained. Notably, the expresion of more than 1/3 CrWRKY genes were regulated by MeJA or YE, indicating that these CrWRKYs are likely involed in the signalling webs which modulate the biosynthesis of terpenoid indole alkaloid and plant responses to various stresses. The present results provide a framework for functional identification of the CrWRKYs and understanding of the regulation network of terpenoid indole alkaloid biosynthesis in Catharanthus roseus.