Metabolic Activation of Fluoropyrrolidine Dipeptidyl Peptidase-IV Inhibitors by Rat Liver Microsomes

Abstract The current study evaluated the potential for two dipeptidyl peptidase-IV (DPP-IV) inhibitor analogues (MRL-A and MRL-B), containing a fluoropyrrolidine moiety in the structure, to undergo metabolic activation. The irreversible binding of these tritiumlabeled compounds to rat liver microsomal protein was time-and NADPH-dependent, and was attenuated by the addition of reduced glutathione (GSH) or N-acetylcysteine (NAC) to the incubation, indicating that chemically reactive intermediates were formed and trapped by these nucleophiles. Mass spectrometric analyses and further trapping experiments with semicarbazide indicated that the fluoropyrrolidine ring had undergone sequential oxidation and defluorination events resulting in the formation of GSH or NAC conjugates of the pyrrolidine moiety. The bioactivation of MRL-A was catalyzed primarily by rat recombinant cytochrome (CYP) 3A1 and 3A2. Pretreatment of rats with prototypic CYP3A1 and 3A2 inducers (pregnenolone-16alpha-carbonitrile (PCN) and dexamethasone) enhanced the extent of bioactivation, which in turn, led to a higher degree of in vitro irreversible binding to microsomal proteins (5-and 9-fold increase, respectively). Herein, we describe studies which demonstrate that the fluoropyrrolidine ring is prone to metabolic activation, and that GSH or NAC can trap the reactive intermediates to form adducts that provide insight into the mechanisms of bioactivation

Lack of Association Between DJ-1 Gene Promoter Polymorphism and the Risk of Parkinson’s Disease

Low DJ-1 protein level caused by DJ-1 gene mutation leads to autosomal recessive Parkinson’s disease (PD) due to impaired antioxidative activity. In sporadic PD patients, although mutations were rarely found, lower DJ-1 protein level was also reported. Dysregulation of DJ-1 gene expression might contribute to low DJ-1 protein level. Since the promoter is the most important element to initiate gene expression, whether polymorphisms in the DJ-1 promoter result in the dysregulation of gene expression, thus leading to low protein level and causing PD, is worth exploring. The DJ-1 promoter region was sequenced in a Chinese cohort to evaluate possible links between DJ-1 promoter polymorphisms, PD risk and clinical phenotypes. Dual-luciferase reporter assay was conducted to evaluate the influence of promoter polymorphisms on DJ-1 transcriptional activity. Related information in an existing genome-wide association studies (GWAS) database were looked up, meta-analysis of the present study and other previous reports was conducted, and expression quantitative trait loci (eQTL) analysis was performed to further explore the association. Three single nucleotide polymorphisms (SNPs) (rs17523802, rs226249, and rs35675666) and one 18 bp deletion (rs200968609) were observed in our cohort. However, there was no significant association between the four detected genetic variations and the risk of PD either in allelic or genotype model, in single-point analysis or haplotype analysis. This was supported by the meta-analysis of this study and previous reports as well as that of GWAS database PDGene. Dual luciferase reporter assay suggested these promoter polymorphisms had no influence on DJ-1 transcriptive activity, which is consistent with the eQTL analysis results using the data from GTEx database. Thus, DJ-1 promoter polymorphisms may play little role in the dysregulation of DJ-1 expression and PD susceptibility in sporadic PD

Resilient and finite‐time H∞ control of semi‐Markov jump systems with both upper and lower thresholds of sojourn time

International audienceThis article discusses the finite‐time control problem for a type of discrete‐time semi‐Markov jump systems (SMJSs) with partial unavailable information. A mode‐dependent resilient state feedback control strategy and the incomplete semi‐Markov kernel (SMK) method are applied to stabilize the obtained closed‐loop systems to protect against additive disturbances that can easily occur in the controller. By considering the upper and lower thresholds of sojourn time for each mode, the number of jumps of SMJSs is effectively estimated and new finite‐time bounded related criteria are established, which cover the general case of some previous studies and are more practical in depicting systems. Besides, the performance is further discussed and optimization problems are presented to achieve better closed‐loop performance. At last, a simulation example and a practical example are exhibited to reveal the validity of our raised control strategies and theoretical results

Expression of Ki-67 and P16 are related with HPV in squamous cell carcinoma of the external auditory canal

<jats:sec><jats:title>Background</jats:title><jats:p> Squamous cell carcinoma of the external auditory canal (EACSCC) is an uncommon tumor and responsible for no more than 0.2% of all the head and neck malignancies. Although there is remarkable research evidence exhibiting that high-risk human papillomavirus (HPV) accounts for considerable head and neck malignancies, its role in the pathogenesis of EACSCC is yet to be determined. </jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p> We evaluated 16 patients with EACSCC treated at our department. We employed PCR to assay for high-risk subtypes of HPV. Two pathologists reviewed the histopathological staining via hematoxylin and eosin along with immunohistochemical staining of p16<jats:sup>INK4a</jats:sup> and Ki-67. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> Detection of HPV DNA was done via PCR in 3 (18.75%) patients, and 8 (50%) positive (+) cases were determined via p16<jats:sup>INK4a</jats:sup> immunostaining. Besides, 3 (37.5%) individuals were HPV positive as per p16<jats:sup>INK4a</jats:sup> PCR results. In addition, all of the p16<jats:sup>INK4a</jats:sup>-positive specimens were diagnosed as moderately differentiated carcinomas. </jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p> Expression of Ki-67 was related to HPV status. This is the first report implicating high-risk HPV in squamous cell carcinoma of the external auditory canal. However, p16<jats:sup>INK4a</jats:sup> immunostaining is a suspectable approach for diagnosing HPV for EACSCC. In addition, HPV might enhance an elevated proliferation rate in EACSCC, illustrated via expression of Ki-67. </jats:p></jats:sec><jats:sec><jats:title>Graphical Abstract</jats:title><jats:p> </jats:p></jats:sec&gt

Association of dual electronic cigarettes and marijuana use with sleep duration among adults from the United States, NHANES 2015–2018

Electronic cigarette (e-cigarette) use is becoming more widespread, and studies show that they are not absolutely harmless. To investigate the association between the dual use of e-cigarettes and marijuana with sleep duration among adults in the United States, this cross-sectional study used data from 6,573 participants aged 18–64 years from 2015 to 2018 from the National Health and Nutrition Examination Survey database. Chi-square tests and analysis of variance were used for bivariate analyses of binary and continuous variables, respectively. Multinomial logistic regression models were used for univariate and multivariate analyses of e-cigarette use, marijuana use, and sleep duration. Sensitivity analyses were conducted in populations with dual e-cigarette and traditional cigarette use and dual marijuana and traditional cigarette use. People who concurrently use e-cigarettes and marijuana had higher odds of not having the recommended sleep duration than neither users (short sleep duration: odds ratio [OR], 2.34; 95% confidence interval [CI], 1.19–4.61; P = 0.014; long sleep duration: OR, 2.09; 95% CI, 1.53–2.87; P < 0.001) and a shorter sleep duration than e-cigarette only users (OR, 4.24; 95% CI, 1.75–4.60; P < 0.001). Concurrent traditional cigarette and marijuana users had higher odds of long sleep duration than neither users (OR, 1.98; 95% CI, 1.21–3.24; P = 0.0065). Almost half of the people who concurrently use e-cigarettes and marijuana had both short and long sleep durations compared to neither users and short sleep duration compared to e-cigarette only users. Longitudinal randomized controlled trials are needed to explore the joint effect of dual tobacco use on sleep health

G-quadruplexes promote the motility in MAZ phase-separated condensates to activate CCND1 expression and contribute to hepatocarcinogenesis

Abstract G-quadruplexes (G4s) can recruit transcription factors to activate gene expression, but detailed mechanisms remain enigmatic. Here, we demonstrate that G4s in the CCND1 promoter propel the motility in MAZ phase-separated condensates and subsequently activate CCND1 transcription. Zinc finger (ZF) 2 of MAZ is a responsible for G4 binding, while ZF3-5, but not a highly disordered region, is critical for MAZ condensation. MAZ nuclear puncta overlaps with signals of G4s and various coactivators including BRD4, MED1, CDK9 and active RNA polymerase II, as well as gene activation histone markers. MAZ mutants lacking either G4 binding or phase separation ability did not form nuclear puncta, and showed deficiencies in promoting hepatocellular carcinoma cell proliferation and xenograft tumor formation. Overall, we unveiled that G4s recruit MAZ to the CCND1 promoter and facilitate the motility in MAZ condensates that compartmentalize coactivators to activate CCND1 expression and subsequently exacerbate hepatocarcinogenesis

TWEAK Signaling‐Induced ID1 Expression Drives Malignant Transformation of Hepatic Progenitor Cells During Hepatocarcinogenesis

Abstract The malignant transformation of hepatic progenitor cells (HPCs) in the inflammatory microenvironment is the root cause of hepatocarcinogenesis. However, the potential molecular mechanisms are still elusive. The HPCs subgroup is identified by single‐cell RNA (scRNA) sequencing and the phenotype of HPCs is investigated in the primary HCC model. Bulk RNA sequencing (RNA‐seq) and proteomic analyses are also performed on HPC‐derived organoids. It is found that tumors are formed from HPCs in peritumor tissue at the 16th week in a HCC model. Furthermore, it is confirmed that the macrophage‐derived TWEAK/Fn14 promoted the expression of inhibitor of differentiation‐1 (ID1) in HPCs via NF‐κB signaling and a high level of ID1 induced aberrant differentiation of HPCs. Mechanistically, ID1 suppressed differentiation and promoted proliferation in HPCs through the inhibition of HNF4α and Rap1GAP transcriptions. Finally, scRNA sequencing of HCC patients and investigation of clinical specimens also verified that the expression of ID1 is correlated with aberrant differentiation of HPCs into cancer stem cells, patients with high levels of ID1 in HPCs showed a poorer prognosis. This study provides important intervention targets and a theoretical basis for the clinical diagnosis and treatment of HCC