New Frontiers in Health Literacy: Using ChatGPT to Simplify Health Information for People in the Community.

BACKGROUND: Most health information does not meet the health literacy needs of our communities. Writing health information in plain language is time-consuming but the release of tools like ChatGPT may make it easier to produce reliable plain language health information. OBJECTIVE: To investigate the capacity for ChatGPT to produce plain language versions of health texts. DESIGN: Observational study of 26 health texts from reputable websites. METHODS: ChatGPT was prompted to 'rewrite the text for people with low literacy'. Researchers captured three revised versions of each original text. MAIN MEASURES: Objective health literacy assessment, including Simple Measure of Gobbledygook (SMOG), proportion of the text that contains complex language (%), number of instances of passive voice and subjective ratings of key messages retained (%). KEY RESULTS: On average, original texts were written at grade 12.8 (SD = 2.2) and revised to grade 11.0 (SD = 1.2), p < 0.001. Original texts were on average 22.8% complex (SD = 7.5%) compared to 14.4% (SD = 5.6%) in revised texts, p < 0.001. Original texts had on average 4.7 instances (SD = 3.2) of passive text compared to 1.7 (SD = 1.2) in revised texts, p < 0.001. On average 80% of key messages were retained (SD = 15.0). The more complex original texts showed more improvements than less complex original texts. For example, when original texts were ≥ grade 13, revised versions improved by an average 3.3 grades (SD = 2.2), p < 0.001. Simpler original texts (< grade 11) improved by an average 0.5 grades (SD = 1.4), p < 0.001. CONCLUSIONS: This study used multiple objective assessments of health literacy to demonstrate that ChatGPT can simplify health information while retaining most key messages. However, the revised texts typically did not meet health literacy targets for grade reading score, and improvements were marginal for texts that were already relatively simple.

Proper imputation of missing values in proteomics datasets for differential expression analysis.

Label-free shotgun proteomics is an important tool in biomedical research, where tandem mass spectrometry with data-dependent acquisition (DDA) is frequently used for protein identification and quantification. However, the DDA datasets contain a significant number of missing values (MVs) that severely hinders proper analysis. Existing literature suggests that different imputation methods should be used for the two types of MVs: missing completely at random or missing not at random. However, the simulated or biased datasets utilized by most of such studies offer few clues about the composition and thus proper imputation of MVs in real-life proteomic datasets. Moreover, the impact of imputation methods on downstream differential expression analysis-a critical goal for many biomedical projects-is largely undetermined. In this study, we investigated public DDA datasets of various tissue/sample types to determine the composition of MVs in them. We then developed simulated datasets that imitate the MV profile of real-life datasets. Using such datasets, we compared the impact of various popular imputation methods on the analysis of differentially expressed proteins. Finally, we make recommendations on which imputation method(s) to use for proteomic data beyond just DDA datasets.

A computational study on bifunctional 1T-MnS2 with an adsorption-catalysis effect for lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries are promising rechargeable energy storage systems with a high energy density, environmental friendliness and low cost. However, the commercialization process of Li-S batteries has been seriously hindered by the shuttling of lithium polysulfides (LiPSs) and the sluggish kinetics of conversion reaction among sulfur species. In this work, the adsorption-catalysis performance of five transition metal disulfide 1T-MS2 (M = Mn, V, Ti, Zr, and Hf) surfaces is investigated by evaluating the adsorption energy of sulfur species, Li-ion diffusion energy barrier, decomposition energy barrier of Li2S, and the Gibbs free energy barrier of the sulfur reduction reaction based on first-principles calculations. Our results show that the sulfiphilicity of 1T-MS2 plays an important role in the adsorption behavior of short-chain sulfur species, in addition to lithiophilicity. Remarkably, among the five 1T-MS2 materials, our results confirm that 1T-TiS2 and 1T-VS2 show excellent adsorption-catalysis performance and it is predicted that 1T-MnS2 is an even better candidate catalyst to inhibit the shuttle effect and accelerate delithiation/lithiation kinetics. Moreover, the outstanding performance of 1T-MnS2 persists in a solvent environment and under strain modulation. Our results not only demonstrate that 1T-MnS2 is an excellent potential catalyst for high-performance Li-S batteries, but also provide great insights into the adsorption-catalysis mechanism during the cycling process.

Cryo-EM of α-tubulin isotype-containing microtubules revealed a contracted structure of α4A/ß2A microtubules.

Microtubules are hollow α/ß-tubulin heterodimeric polymers that play critical roles in cells. In vertebrates, both α- and ß-tubulins have multiple isotypes encoded by different genes, which are intrinsic factors in regulating microtubule functions. However, the structures of microtubules composed of different tubulin isotypes, especially α-tubulin isotypes, remain largely unknown. Here, we purify recombinant tubulin heterodimers composed of different mouse α-tubulin isotypes, including α1A, α1C and α4A, with the ß-tubulin isotype ß2A. We further assemble and determine the cryo-electron microscopy (cryo-EM) structures of α1A/ß2A, α1C/ß2A, and α4A/ß2A microtubules. Our structural analysis demonstrates that α4A/ß2A microtubules exhibit longitudinal contraction between tubulin interdimers compared with α1A/ß2A and α1C/ß2A microtubules. Collectively, our findings reveal that α-tubulin isotype composition can tune microtubule structures, and also provide evidence for the "tubulin code" hypothesis.

Use of oral glucose tolerance testing and HbA1c at 6-14 gestational weeks to predict gestational diabetes mellitus in high-risk women.

PURPOSE: To study the prediction of gestational diabetes mellitus (GDM) in high-risk pregnant women by testing fasting blood glucose, 1-h(1hPG) and 2-h plasma glucose (2hPG) after an oral glucose tolerance test, and glycated hemoglobin (HbA1c) in early pregnancy (6-14 weeks). METHODS: We recruited 1311 pregnant women at high risk for diabetes from the Obstetrics Clinic of Daxing District People's Hospital between June 2017 and December 2019. The tests performed during the first trimester included fasting blood glucose (FPG), HbA1c, and 75-g oral glucose tolerance test (OGTT) with 1hPG and 2hPG. Seventy-three pregnant women diagnosed with pregestational diabetes mellitus (PGDM) early in pregnancy and 36 who were missed in the second trimester were excluded. A total of 1202 women were followed up until 24-28 weeks for GDM. The receiver operating characteristic (ROC) and area under the ROC curve (AUC) were calculated to determine the predictive values of FPG, 1hPG, 2hPG, and HbA1c for GDM in early pregnancy in high-risk pregnant women. RESULTS: The AUC for 1hPG for the prediction of GDM in high-risk pregnant women was greater than those for FPG, 2hPG, and HbA1c. All differences were significant. The AUCs for the predictive values of FPG, 1hPG, 2hPG, and HbA1c in high-risk pregnant women were 0.63, 0.76, 0.71, and 0.67, respectively. The prevalence of PGDM among pregnant women at high risk of diabetes was 5.6%. CONCLUSION: First-trimester levels of FPG, 1hPG, 2hPG, and HbA1c in high-risk women are significant predictors of GDM, with 1hPG having the most significant predictive value.

The green tea polyphenol epigallocatechin-3-gallate attenuates age-associated muscle loss via regulation of miR-486-5p and myostatin.

(-)-Epigallocatechin-3-gallate (EGCG), the most abundant catechin component in green tea, has been reported to attenuate age-associated insulin resistance, lipogenesis and loss of muscle mass through restoring Akt activity in skeletal muscle in our previous and present studies. Accumulated data has suggested that polyphenols regulate signaling pathways involved in aging process such as inflammation and oxidative stress via modulation of miRNA expression. Here we found that miRNA-486-5p was significantly decreased in both aged senescence accelerated mouse-prone 8 (SAMP8) mice and late passage C2C12 cells. Thus, we further investigated the regulatory effect of EGCG on miRNA-486-5p expression in age-regulated muscle loss. SAMP8 mice were fed with chow diet containing without or with 0.32% EGCG from aged 32 weeks for 8 weeks. Early passage (<12 passages) and late passage (>30 passages) of C2C12 cells were treated without or with EGCG at concentrations of 50 µM for 24h. Our data showed that EGCG supplementation increased miRNA-486-5p expression in both aged SAMP8 mice and late passage C2C12 cells. EGCG stimulated AKT phosphorylation and inhibited FoxO1a-mediated MuRF1 and Atrogin-1 transcription via up-regulating the expression of miR-486 in skeletal muscle of 40-wk-old SAMP8 mice as well as late passage C2C12 cells. In addition, myostatin expression was increased in late passage C2C12 cells and anti-myostatin treatment upregulated the expression of miR-486-5p. Our results identify a unique mechanism of a dietary constituent of green tea and suggest that use of EGCG or compounds derived from it attenuates age-associated muscle loss via myostatin/miRNAs/ubiquitin-proteasome signaling.

Dysregulations of mitochondrial quality control and autophagic flux at an early age lead to progression of sarcopenia in SAMP8 mice.

The senescence-accelerated mouse (SAM) prone 8 (SAMP8) has been demonstrated for muscular aging research including sarcopenia, but its underlying mechanisms remain scarce. Physiological indices and histology of skeletal muscle were analyzed in SAMP8 mice at different ages. SAMP8 mice exhibited typical features of sarcopenia at 40 weeks of age and were more time-efficient than that at 88 weeks of age in bothSAM resistant 1 (SAMR1) and C57BL/6 mice. Increase in FoxO3a-mediated transcription of Atrogin-1 and MuRF1 and decrease in phosphorylated mTOR/P70s6k were observed at week 40 in SAMP8 mice. High oxidative stress was observed from week 24 and persisted to week 40 in SAMP8 mice evidenced by overexpression of protein carbonyl groups and reduced activities of CAT, SOD, and GPx. Downregulation of genes involved in mitochondrial biogenesis (PGC-1α, Nrf-1, Tfam, Ndufs8, and Cox5b) and in mitochondrial dynamics fission (Mfn2 and Opa1) from week 24 indicated dysregulation of mitochondrial quality control in SAMP8 mice. Impaired autophagic flux was observed in SAMP8 mice evidenced by elevated Atg13 and LC3-II accompanied with the accumulation of P62 and LAMP1. Increases in inflammatory factors (IL-6 and MCP-1), adipokines (leptin and resistin), and myostatin in serum at week 32 and decline in Pax7+ satellite cell resided next to muscle fibers at week 24 implied that muscle microenvironment contributed to the progression of sarcopenia in SAMP8 mice. Our data suggest that early alterations of mitochondrial quality control and autophagic flux worsen muscle microenvironment prior to the onset of sarcopenia.

LncRNA HOTAIR modulates the expression of OATP1B1 in HepG2 cells by sponging miR-206/miR-613.

OATP1B1 is an important drug transporter with a complex regulatory mechanism. In this study, we wanted to investigate how LncRNA HOTAIR regulates the expression of OATP1B1 through its action on miR-206/miR-613 in HepG2 cells. The expression level of LncRNA HOTAIR, miR-206/miR-613, and OATP1B1 mRNA was detected by RT-qPCR, and the OATP1B1 protein level was detected by Western blot. The competitive endogenous RNA mechanism was validated by bioinformatics analysis and a dual-luciferase reporter gene assay. Our results showed that over- or under-expression of LncRNA HOTAIR correspondingly significantly increased or decreased the protein level of OATP1B1 in HepG2 cells, while no significant change in OATP1B1 mRNA level was observed. In addition, the stimulatory or inhibitory effect of LncRNA HOTAIR on OATP1B1 protein expression was correspondingly reversed by miR-206/miR-613 mimic or miR-206/miR-613 inhibitor. Finally, the reporter gene assay revealed that LncRNA HOTAIR can sponge miR-206/miR-613, which breaks the binding site of miR-206/miR-613 and OATP1B1 mRNA 3'-UTR, eliminating the stimulatory effect of LncRNA HOTAIR on OATP1B1 protein. Thus, we conclude that LncRNA HOTAIR can affect the expression of OATP1B1 in HepG2 cells by sponging miR-206/miR-613, which, in turn, prevents the binding of miR-206/miR-613 and OATP1B1 mRNA 3'-UTR.

Modulation of transporter activity of OATP1B1 and OATP1B3 by the major active components of Radix Ophiopogonis.

Radix Ophiopogonis is often an integral part of many traditional Chinese formulas, such as Shenmai injection used to treat cardio-cerebrovascular diseases. This study aimed to investigate the influence of the four active components of Radix Ophiopogonis on the transport activity of OATP1B1 and OATP1B3. The uptake of rosuvastatin in OATP1B1-HEK293T cells were stimulated by methylophiopogonanone A (MA) and ophiopogonin D' (OPD') with EC50 calculated to be 11.33 ± 2.78 and 4.62 ± 0.64 µM, respectively. However, there were no remarkable influences on rosuvastatin uptake in the presence of methylophiopogonanone B (MB) or ophiopogonin D (OPD). The uptake of atorvastatin in OATP1B1-HEK293T cells can be increased by MA, MB, OPD and OPD' with EC50 calculated to be 6.00 ± 1.60, 13.64 ± 4.07, 10.41 ± 1.28 and 3.68 ± 0.85 µM, respectively. The uptake of rosuvastatin in OATP1B3-HEK293T cells was scarcely influenced by MA, MB and OPD, but was considerably increased by OPD' with an EC50 of 14.95 ± 1.62 µM. However, the uptake of telmisartan in OATP1B3-HEK293T cells was notably reduced by OPD' with an IC50 of 4.44 ± 1.10 µM, and barely affected by MA, MB and OPD. The four active components of Radix Ophiopogonis affect the transporting activitives of OATP1B1 and OATP1B3 in a substrate-dependent manner.

Pharmacokinetic analysis of plasma bicyclol by liquid chromatography-tandem mass spectrometry.

Bicyclol is a synthetic drug widely used to treat chronic hepatitis B. This study aimed to develop a selective, sensitive and high-throughput liquid chromatography-tandem mass spectrometric method for the detection of bicyclol in human plasma. Bicyclol was detected using a multiple reaction monitoring mode, with ammonium adduct ions (m/z 408.2) as the precursor ion and the [M-CH3 ]+ ion (m/z 373.1) subjected to demethylation as the product ion. Chromatographic separation was achieved using a Zobax Eclipse XDB-C18 column with a gradient elution and a mobile phase of 2 mm ammonium formate and acetonitrile. Bicyclol was extracted from plasma matrix by precipitation. A linear detection response was obtained for bicyclol ranging from 0.500 to 240 ng/mL, and the lower limit of quantification was 0.500 ng/mL. The intra- and inter-day precisions were all ≤7.4%, and the accuracies were within ±6.0%. The extraction recovery was >95.9%, and the matrix effects were between 96.0% and 108%. Bicyclol was found to be unstable in human plasma at room temperature, but the degradation was minimized by conducting sample collection and preparation in an ice bath. The validated method was successfully applied to investigate the pharmacokinetics of bicyclol tablets in six healthy Chinese volunteers.

Effect of panaxytriol on cytochrome P450 3A4 via the pregnane X receptor regulatory pathway.

Panaxytriol (PXT) is one of the major effective components of red ginseng and Shenmai injection. The present study aimed to explore the effect of PXT on cytochrome P450 3A4 (CYP3A4) based on the pregnane X receptor (PXR)-CYP3A4 regulatory pathway in HepG2 cells and hPXR-overexpressing HepG2 cells treated with PXT for different time periods using quantitative polymerase chain reaction, Western blot, and dual-luciferase reporter gene assays. PXT could upregulate the levels of PXR and CYP3A4 mRNA in HepG2 cells treated with PXT for 1 hr, with no impact on the expression of their protein levels. The expression levels of both PXR and CYP3A4 mRNA and protein in HepG2 cells treated with PXT for 24 hr increased in a concentration-dependent manner. The effects of PXT on the expression of PXR and CYP3A4 mRNA and protein in hPXR-overexpressing HepG2 cells were similar to those in HepG2 cells. Moreover, the influence trend of PXT on CYP3A4 was consistent with that of PXR in HepG2 cells and hPXR-overexpressing HepG2 cells. The dual-luciferase reporter gene assay in HepG2 cells further demonstrated that PXT treatment for specific time periods could significantly induce the expression of CYP3A4 mediated by the PXR regulatory pathway.

Stomatin plays a suppressor role in non-small cell lung cancer metastasis.

OBJECTIVE: Metastasis is one of the key causes of high mortality in lung cancer. Aberrant DNA methylation is a common event in metastatic lung cancer. We aimed to identify new epigenetic regulation of metastasis-associated genes and characterize their effects on lung cancer progression. METHODS: We screened genes associated with non-small cell lung cancer (NSCLC) metastasis by integrating datasets from the Gene Expression Omnibus (GEO) database. We obtained epigenetic-regulated candidate genes by analyzing the expression profile of demethylation genes. By overlapping analysis, epigenetically modulated metastasis-associated genes were obtained. Kaplan-Meier plotter (KM plotter) was utilized to assess the overall survival (OS) of stomatin in lung cancer. Immunohistochemistry (IHC) was conducted to determine the association between stomatin and metastasis-associated clinical indicators. Both in vitro and in vivo assays were performed to investigate the potential role of stomatin in metastasis. The regulation mechanisms of transforming growth factor ß1 (TGFß1) on stomatin were determined by Sequenom MassARRAY quantitative methylation and western blot assays. RESULTS: A series of bioinformatic analyses revealed stomatin as the metastasis-associated gene regulated by DNA methylation. The KM plotter analysis showed a positive association between stomatin and the OS of lung cancer. IHC analysis indicated that the decreased stomatin expression is linked with advanced TNM stage. Loss- and gain-of-function experiments displayed that stomatin could inhibit the migration and invasion of NSCLC cells. Furthermore, TGFß1 repressed stomatin expression during epithelial-to-mesenchymal transition (EMT). The negative correlation between stomatin and TGFß1 was also validated in advanced stage III lung tumor samples. The underlying mechanism by which TGFß1 inhibits stomatin is due in part to DNA methylation. CONCLUSIONS: Our results suggest that stomatin may be a target for epigenetic regulation and can be used to prevent metastatic diseases.

[Ruyi Jinhuang Plaster suppresses BPH by reducing the expressions of P38, JNK2, NF-кBP65 and STAT3 in the prostate tissue of rats].

OBJECTIVE: To investigate the effect of Ruyi Jinhuang Plaster (RJP) on testosterone propionate-induced BPH in the rat model and its action mechanisms. METHODS: Forty-eight SD male rats were randomly divided into six groups of equal number: normal control, BPH model control, finasteride, and high-, medium- and low-dose RJP. The BPH model was made in the latter five groups by hypodermic injection of testosterone propionate. From the first day of modeling, the rats of the normal control and BPH model control groups were treated with blank plasters and those of the high-, medium- and low-dose RJP groups with RJPs at 42.0, 21.0 and 10.5 cm2/kg applied to the dehaired area of the back, and those of the finasteride group by gavage of finasteride at 4.5 mg/kg, all once a day for 30 successive days. Then the prostates of the animals were harvested for observation of histopathological changes by HE staining, measurement of the areas of interstitial and epithelial cells and prostatic glandular cavity, and determination of the expressions of P38, JNK2, NF-кBP65 and STAT3 proteins in the prostate tissue by Western blot. RESULTS: Compared with the BPH model controls, the high-dose RJP group showed significantly decreased proliferation and area proportion of prostatic epithelial cells (P < 0.05), increased area proportion of the prostatic glandular cavity (P < 0.05), and reduced expressions of P38, p-P38, NF-кBP65, P-NF-кBP65, STAT3, P-STAT3 and JNK2 in the prostate tissue (P < 0.05); the medium-dose RJP group exhibited markedly down-regulated expressions of JNK2 and NF-кBP65 (P < 0.05) but an up-regulated level of p-JNK (P < 0.05); while the low-dose RJP group displayed a remarkably reduced expression of JNK2 (P < 0.05) but an elevated level of p-JNK (P < 0.05). CONCLUSIONS: RJP suppresses BPH in the model rat by down-regulating the expressions of P38, p-P38, NF-кBP65, P-NF-кBP65, STAT3, P-STAT3 and JNK2 or up-regulating that of p-JNK in the prostate tissue.

In vitro inhibition of UGT1A3, UGT1A4 by ursolic acid and oleanolic acid and drug-drug interaction risk prediction.

1. Ursolic acid (UA) and oleanolic acid (OA) may have important activity relevant to health and disease prevention. Thus, we studied the activity of UA and OA on UDP-glucuronosyltransferases (UGTs) and used trifluoperazine as a probe substrate to test UGT1A4 activity. Recombinant UGT-catalyzed 4-methylumbelliferone (4-MU) glucuronidation was used as a probe reaction for other UGT isoforms. 2. UA and OA inhibited UGT1A3 and UGT1A4 activity but did not inhibit other tested UGT isoforms. 3. UA-mediated inhibition of UGT1A3 catalyzed 4-MU-ß-d-glucuronidation was via competitive inhibition (IC50 0.391 ± 0.013 µM; Ki 0.185 ± 0.015 µM). UA also competitively inhibited UGT1A4-mediated trifluoperazine-N-glucuronidation (IC50 2.651 ± 0.201 µM; Ki 1.334 ± 0.146 µM). 4. OA offered mixed inhibition of UGT1A3-mediated 4-MU-ß-d-glucuronidation (IC50 0.336 ± 0.013 µM; Ki 0.176 ± 0.007 µM) and competitively inhibited UGT1A4-mediated trifluoperazine-N-glucuronidation (IC50 5.468 ± 0.697 µM; Ki 6.298 ± 0.891 µM). 5. Co-administering OA or UA with drugs or products that are substrates of UGT1A3 or UGT1A4 may produce drug-mediated side effects.

Inhibitory Effect of Hesperetin and Naringenin on Human UDP-Glucuronosyltransferase Enzymes: Implications for Herb-Drug Interactions.

Hesperetin (HET) and naringenin (NGR) are flavanones found in citrus (oranges and grapefruit) and Aurantii Fructus Immaturus. The present study aims to investigate the inhibition potential of HET and NGR derivatives towards one of the most important phase II drug-metabolizing enzymes-uridine diphosphate (UDP)-glucuronosyltransferases (UGTs). We used trifluoperazine as a probe substrate to test UGT1A4 activity, and recombinant UGT-catalyzed 4-methylumbelliferone glucuronidation was used as a probe reaction for other UGT isoforms. Data show that HET and NGR displayed broad-spectrum inhibition against human UGTs. Besides, HET exhibited strong inhibitory effects on UGT1A1, 1A3 and 1A9 (both IC50 and Ki values lower than 10 µM), and the inhibitory effects of NGR against three major UGTs, including UGT1A1, 1A3 and 2B7. In a combination of inhibition parameters (Ki) and in vivo concentration of HET and NGR, the potential in vivo inhibition magnitude was predicted. Based on the reported maximum plasma concentration of HET and NGR in vivo, these findings indicate the potential herb-drug interactions (HDI) between HET or NGR and the drugs mainly undergoing UGT1A3 or UGT2B7 catalyzed metabolic elimination. Considering the variety of citrus that contains HET and NGR, so caution should be applied when taking drugs that utilize UGTs for metabolism and clearance with citrus fruits.

[Effect and mechanism of miR-206/miR-613 on expression of OATP1B1].

This study was designed to explore the effect and mechanism of miR-206/miR-613 on the expression of OATP1B1 gene. Bioinformatic analysis was used to predict the potential miRNAs target sites in 3'-untranslated region (3'-UTR) of OATP1B1 mRNA. The expression level of miR-206/miR-613 and OATP1B1 mRNA and protein was determined with RT-qPCR and Western blot, respectively. Luciferase assay was used to explore the exact mechanism of the effect of miR-206/miR-613 on the expression of OATP1B1 mRNA and protein. The results showed that the seed sequences of miR-206/miR-613 has perfect complementary with 3'-UTR of OATP1B1 mRNA in terms of sequence specificity. The secondary structure between miR-206/ miR-613 and 3'-UTR of OATP1B1 mRNA was rather stable. The OATP1B1 protein level was down-regulated by 24.7%, 38.8% by overexpression of miR-206/miR-613. The expression was up-regulated by 25%, 38.2% by inhibition of miR-206/miR-613. However, overexpression or inhibition of miR-206/miR-613 had no effect on the expression of OATP1B1 mRNA. The luciferase activity of p MIR/OATP1B1-WT luciferase reporter gene was decreased by 35% and 30% through overexpression of miR-206/miR-613. The expression was increased by 33.1% and 32.5% through inhibition of miR-206/miR-613. When the binding sites in the 3'-UTR of OATP1B1 mRNA complementary with miR-206/miR-613 was mutated, overexpression or inhibition of miR-206/miR-613 had no effect on the luciferase activity. Collectively, miR-206/miR-613 post-transcriptionally regulates the expression of OATP1B1 protein by directly targeting the 3'-UTR of OATP1B1 mRNA.

Cloning and characterization of a phytoene dehydrogenase gene from marine yeast Rhodosporidium diobovatum.

Carotenoids are a naturally occurring and widely distributed group of pigments that provide protection against photooxidation and inactivate free radicals due to their highly conjugated double-bond systems. Phytoene dehydrogenation is the first rate-limiting step in the carotenoid biosynthetic pathway. Phytoene dehydrogenase is the key enzyme in the transformation of carotenoid from colorless to colored; therefore it is the first target of gene manipulation. The present study describes the identification and functional characterization of a carontenoid synthesis gene from Rhodosporidium diobovatum, designated as crtI, which catalyzes the dehydrogenation of phytoene. We obtained a full-length cDNA clone of crtI, encoding phytoene dehydrogenase (EC Number: 1.3.99.31), from R. diobovatum ATCC 2527 by rapid amplification of cDNA ends. Complementation mapping of the crtI gene in Escherichia coli allowed us to localize the regions responsible for phytoene dehydrogenase function within the protein. Enzyme activity of the expressed protein in E. coli was verified using high performance liquid chromatography analysis. We were able to determine the nucleotide sequence of crtI from R. diobovatum. The publicly available sequence will be useful in future studies on phytoene dehydrogenase.

Mechanism of Action of Panaxytriol on Midazolam 1'-Hydroxylation and 4-Hydroxylation Mediated by CYP3A in Liver Microsomes and Rat Primary Hepatocytes.

In our previous study, panaxytriol (PXT) was shown to enhance midazolam (MDZ) 1'-hydroxylation significantly but to inhibit MDZ 4-hydroxylation. To explore the underlying mechanism, we investigated the effects of PXT on cytochrome P450 3A (CYP3A)-mediated MDZ metabolic pathways using rat liver microsomes (RLM), human liver microsomes (HLM), and rat primary hepatocytes. In the presence of PXT, the Vmax of 4-OH MDZ decreased from 0.72 to 0.51 nmol/min·mg pro in RLM and from 0.32 to 0.12 nmol/min·mg pro in HLM, and the Km value increased from 5.12 to 7.26 µM in RLM and from 27.87 to 32.80 µM in HLM. But the presence of PXT reduced the Km and increased the Vmax values of MDZ 1'-hydroxylation in RLM and HLM. Interestingly, the differential effect of PXT on MDZ 4-hydroxylation and 1'-hydroxylation was also observed in primary rat hepatocytes after 45-min culture. PXT did not affect the expression levels of CYP3A1/2 mRNA in rat hepatocytes. With extension of the culture time to 6 h, however, PXT significantly inhibited both MDZ 4-hydroxylation and 1'-hydroxylation, and the expression level of CYP3A1/2 mRNA was decreased to 87% and 80% (CYP3A1) and to 89% and 85% (CYP3A2) of those in controls in the presence of PXT 4.0 and 8.0 µg/mL, respectively. These results suggest that PXT could activate MDZ 1'-hydroxylation but inhibit MDZ 4-hydroxylation by changing the CYP3A enzyme affinity and metabolic rate after a short-term intervention. However, long-term treatment with PXT could inhibit both the 4-hydroxylation and 1'-hydroxylation of MDZ by downregulating CYP3A1/2 mRNA expression.

Contribution of cytochrome P450 isoforms to gliquidone metabolism in rats and human.

1. Gliquidone, a second generation sulfonylurea, is a widely used oral antidiabetic drug. Due to the differences in its rate of metabolism, gliquidone shows inter-subject variability in pharmacokinetic and pharmacodynamic profiles. 2. Cytochrome P450 (CYP450) isoforms are involved in the metabolism of a majority of drugs in clinical use and plays a significant role in reducing possible drug interactions. This research aimed to systematically study the contribution of various human CYP450 isoforms to gliquidone metabolism in vitro in rats and human. 3. In rat liver microsomes, gliquidone was metabolized mainly by the most abundant CYP2C. The other isoforms involved in the metabolism included CYP3A, CYP2D, CYP1A and CYP2E. 4. Further investigation of rat recombinant enzymes showed that CYP3A1 and CYP2C11 played a major role in gliquidone metabolism in vitro, while CYP2D1, CYP1A2 and CYP2E1 were also involved. 5. But the metabolism of gliquidone in the human liver microsomes was mainly mediated by CYP3A4. The other isoforms involved in this process were CYP2C9, CYP2C19 and CYP2D6. 6. The further study of human recombinant enzymes demonstrated that CYP3A4 was the principal isoform enzyme for the metabolism of gliquidone. The intrinsic clearance (Vmax/Km) of CYP3A4 during gliquidone metabolism was 3-12 times greater than that of other CYP450 isoforms including CYP2C9, CYP2D6 and CYP2C19. 7. These findings may assist in valuable prediction of potential interactions of gliquidone with other drugs that are CYP3A4 inhibitors or inducers and help to design more efficacious and safer pharmacotherapy for patients of diabetes mellitus.

Who Should I Engage With at What Time? A Missing Event-Aware Temporal Graph Neural Network.

Temporal graph neural network (GNN) has recently received significant attention due to its wide application scenarios, such as bioinformatics, knowledge graphs, and social networks. There are some temporal GNNs that achieve remarkable results. However, these works focus on future event prediction and are performed under the assumption that all historical events are observable. In real-world applications, events are not always observable, and estimating event time is as important as predicting future events. In this article, we propose, a missing event-aware temporal GNN, which uniformly models evolving graph structure and timing of events to support predicting what will happen in the future and when it will happen. models the dynamic of both observed and missing events as two coupled temporal point processes (TPPs), thereby incorporating the effects of missing events into the network. Experimental results on several real-world temporal graphs demonstrate that significantly outperforms the existing methods with up to 89% and 112% more accurate time and link prediction. Code can be found on https://github.com/HIT-ICES/TNNLS-MTGN.