Double base mismatches mediated catalytic hairpin assembly for enzyme-free single-base mutation detection: integrating signal recognition and amplification in one.

Single nucleotide polymorphism (SNP) biosensors are emerging rapidly for their promising applications in human disease prevention diagnosis, treatment, and prognosis. However, it remains a bottleneck in equipping simple and stable biosensors with the traits of high sensitivity, non-enzyme, and low cost. Double base mismatches mediated chain displacement reactions have attracted fascinating advantages of tailorable thermodynamics stability, non-enzyme, and excellent assembly compliance to involvement in SNP identification. As the base mismatch position and amount in DNA sequence can be artificially adjusted, it provides plenty of selectivity and specificity for exploring perfect biosensors. Herein, a biosensor with double base mismatches mediated catalytic hairpin assembly (CHA) is designed via one base mismatch in the toehold domain and the other base mismatch in the stem sequence of hairpin 1 (H1) by triggering CHA reaction to achieve selective amplification of the mutation target (MT) and fluorescence resonance energy transfer (FRET) effect that is composed of Cy3 and Cy5 terminally attached H1 and hairpin 2 (H2). Depending on the rationally designed base mismatch position and toehold length, the fabricated biosensors show superior SNP detection performance, exhibiting a good linearity with high sensitivity of 6.6 fM detection limit and a broad detection abundance of 1%. The proposed biosensor can be used to detect the KRAS mutation gene in real samples and obtain good recoveries between 106 and 116.99%. Remarkably, these extendible designs of base mismatches can be used for more types of SNP detection, providing flexible adjustment based on base mismatch position and toehold length variations, especially for their thermodynamic model for DNA-strand displacement reactions.

Solvent-promoted photochemical carbonylation of benzylic C-H bonds under iron catalysis.

This paper describes the iron-catalyzed photochemical carbonylation of benzylic C-H bonds resulting in the synthesis of various aryl ketones. Using 5 W blue LED irradiation, the reactions proceed smoothly in the presence of 2 mol% of FeBr3 in MeOH at 35 °C. The catalytic system could be extended for the oxidation of silane, thioether, and phosphine into silenol, sulphoxide, and phosphoxide, respectively. A mechanistic study suggests that a hydrogen bond-stabilized iron-hydroperoxo species is the reactive intermediate. It is shown that the reaction proceeds via a four-electron-transfer pathway, and a benzylic cation seems to be the crucial reactive species. The method is applied for the synthesis of pomalyst, haloperidol, melperone, and lenperone.

Disruption of the mouse Bmal1 locus promotes heterotopic ossification with aging via TGF-beta/BMP signaling.

INTRODUCTION: Heterotopic ossification of tendons and ligaments is a painful and debilitating disease with no effective treatment. Although aging has been reported to be correlated with the occurrence and development of this disease, the mechanism remains unknown. MATERIALS AND METHODS: In the present study, we generated Bmal1-/- mice, which disrupted the circadian clock and displayed premature aging, as an aging model to explore the role of Bmal1 in TGF-beta (ß)/BMP signaling in progressive heterotopic ossification of tendons and ligaments with aging. RESULTS: We first confirmed that BMAL1 expression is downregulated in human fibroblasts from ossification of the posterior longitudinal ligament using online datasets. Bmal1 deficiency in mice caused significantly progressive heterotopic ossification with aging starting at week 6, notably in the Achilles tendons and posterior longitudinal ligaments. Ossification of the Achilles tendons was accompanied by progressive motor dysfunction of the ankle joint. Histology and immunostaining showed markedly increased endochondral ossification in the posterior longitudinal ligaments and Achilles tendons of Bmal1-/- mice. Ligament-derived Bmal1-/- fibroblasts showed an osteoblast-like phenotype, upregulated osteogenic and chondrogenic markers, and activated TGFß/BMP signaling, which was enhanced by TGFß1 stimulation. Furthermore, Bmal1-/- mouse embryonic fibroblasts had a stronger potential for osteogenic differentiation with activation of TGFß/BMP signaling. CONCLUSIONS: These findings demonstrated that Bmal1 negatively regulates endochondral ossification in heterotopic ossification of tendons and ligaments with aging via TGFß/BMP signaling, thereby identifying a new regulatory mechanism in age-related heterotopic ossification of tendons and ligaments.

Dapagliflozin, sildenafil and their combination in monocrotaline-induced pulmonary arterial hypertension.

BACKGROUND: Dapagliflozin, a selective inhibitor of sodium-glucose cotransporter 2 (SGLT2), can reduce cardiovascular events and mortality in patients with heart failure. A number of mechanisms have been proposed to explain the beneficial effects of SGLT2 inhibitors. The purpose of this study was to determine whether dapagliflozin can improve pulmonary vascular remodelling and the efficacy of dapagliflozin as an add-on therapy to sildenafil in rats with pulmonary arterial hypertension (PAH). METHODS: A monocrotaline (MCT)-induced PAH rat model was used in our study. MCT-injected rats were randomly divided into four groups and treated for 3 weeks with daily per os treatment with vehicle, dapagliflozin (1 mg/kg/day), sildenafil (25 mg/kg/day), or a combination of dapagliflozin (1 mg/kg/day) and sildenafil (25 mg/kg/day). Haemodynamic measurements, histological analysis, enzyme-linked immunosorbent assay and western blotting analysis were employed to detect the changes in PAH rats after treatments. RESULTS: Dapagliflozin significantly attenuated MCT-induced increases in right ventricular systolic pressure (RVSP) and right ventricular hypertrophy (RVH) in PAH rats. Dapagliflozin effectively decreased the thickening of pulmonary artery media and decreased the muscularization of pulmonary arterioles in PAH rats. Moreover, dapagliflozin attenuated nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome activation in lung tissues and the levels of interleukin-1ß (IL-1ß) and interleukin-18 (IL-18) in plasma. However, dapagliflozin as an add-on therapy to sildenafil in rats with PAH did not show a more pronounced beneficial effect on right ventricular systolic pressure and pulmonary vascular remodelling in MCT rats than sildenafil alone. CONCLUSIONS: Dapagliflozin reduces right ventricular systolic pressure and pulmonary vascular remodelling in a rat model of PAH. However, combination therapy with dapagliflozin and sildenafil was not more effective than monotherapy with sildenafil in PAH rats.

The PPRD score stratifies patients with hepatocellular carcinoma and portal vein tumor thrombus treated with sorafenib plus transarterial chemoembolization.

OBJECTIVES: To identify clinical prognostic and predictive factors in patients with hepatocellular carcinoma (HCC) and portal vein tumor thrombus (PVTT) undergoing sorafenib plus transarterial chemoembolization (TACE) and establish a prognostic score for these patients. METHODS: Between January 2012 and December 2017, 184 consecutive patients with HCC and PVTT were concurrently treated with sorafenib and TACE. Univariate and multivariate analyses were performed to explore the clinical factors independently correlated with overall survival (OS). A prognostic score was then developed to identify different prognoses in an initial cohort and validated in an external cohort (n = 72). RESULTS: In the multivariate analysis, performance status, extension of PVTT, initial radiological response, and sorafenib-related dermatologic toxicity were identified as predictors associated with OS. These factors were used to develop a prognostic score (PPRD score, range from 0 to 11). The median survival was found to decrease as the PPRD score increased, and patients were stratified into a favorable group (0 points), intermediate group (1-4 points), and dismal group (> 4 points). The median survival of patients in the three groups was 34.0 months, 20.0 months, and 7.0 months, respectively (p < 0.001). Additionally, the time to progression (TTP) (p < 0.001) was stratified along the same prognostic groups. The external validation cohort confirmed the prognostic scores. CONCLUSIONS: The proposed score system can accurately stratify the outcomes of patients with HCC and PVTT treated with sorafenib plus TACE to help identify which group of patients may benefit from treatment. KEY POINTS: • The survival benefits of patients with advanced HCC treated with sorafenib plus TACE remains controversial. • The independent factors associated with survival were identified to develop a prognostic score, called the PPRD score (standing for performance status, PVTT grade, radiological response, and sorafenib-related dermatologic toxicity); the median survival decreases as the score increases. • The scoring system can accurately stratify the survival benefits of patients with HCC and PVTT treated with combination therapy and help to identify which group of patients may benefit from the treatment. Graphical abstract.

Synthesis and biological evaluation of isatin derivatives containing 1,3,4-thiadiazole as potent a-glucosidase inhibitors.

A series of (Z)-3-(2-(1,3,4-thiadiazol-2-yl)hydrazono)-1-substituted indolin-2-ones derivatives (3a-3m) were designed and synthesized. All newly synthesized compounds were evaluated for their a-glucosidase inhibitory activity with resveratrol as positive control in vitro. Except for 3i and 3j, all of the compounds showed a potent inhibitory activity against a-glucosidase with IC50 values in the range of 3.12 ± 1.25 to 45.95 ± 1.26 µM and the purity of these compounds was greater than 95%. The IC50 values were being compared to the standard resveratrol (IC50 = 22.00 ± 1.15 µM) and it was found that compounds 3b, 3d-3h were found to be more active than resveratrol. Specifically, (Z)-3-(2-(1,3,4-thiadiazol-2-yl)hydrazono)-1-(4-chlorobenzyl)indolin-2-one (3d) exhibited the most potent a-glucosidase inhibitory activity with IC50 value of 3.12 ± 1.25 µM. The kinetic analysis revealed that compound (3d) is noncompetitive inhibitor. Structure activity relationship has been established for all compounds. Furthermore, the binding interactions of compound 3d with the active site of a-glucosidase were confirmed through molecular docking. This study has identified a new class of potent a-glucosidase inhibitors for further investigation.

Ortho-Hydroxylative ipso-Cyclization of N-arylpropiolamide.

A facile protocol for the tunable synthesis of 10-hydroxy-1-azaspiro[4.5]deca-3,6,8-trien-2-ones and benzo[b]pyrrolo[2,1-c][1,4]oxazin-3-ones is described. A tunable synthesis has been realized by the use of ZnBr2/oxone and tetra-n-butylammonium bromide (TBAB)/oxone. The reaction proceeds smoothly with high efficiency and a broad substrate scope. Mechanistic studies indicate that an N-protecting group-assisted ortho-trapping reaction is involved. In the transformation, the reaction undergoes α-addition, ipso-cyclization, and ortho-trapping of the resulting spirocyclic species.

Synthesis of 3-Hydroxyisoindolin-1-ones through 1,4-Dioxane-Mediated Hydroxylhydrative aza-Cyclization of 2-Alkynylbenzamide in Water.

In this work, 1,4-dioxane-mediated hydroxylhydrative aza-cyclization of 2-alkynylbenzamide is developed for the synthesis of 3-hydroxylisoindolin-1-ones. The transformation proceeds smoothly in water with good yields and a broad reaction scope. Mechanistic studies show that regioselective brimonative 5-exo-dig aza-cyclization, bromohydration of the resulting alkene groups, and hydrolysis of dibromo compounds are involved. Compared to the traditional methodologies, the synthetic procedure reported herein represents a cleaner route toward 3-hydroxylisoindolin-1-ones.

Serum human epididymis protein 4 level as a predictor of clinical worsening in idiopathic pulmonary arterial hypertension: a pilot study.

BACKGROUND: Human epididymis protein 4 (HE4) was proved to be a novel biomarker for left heart failure. The purpose of this exploratory study was to evaluate the role of HE4 in patients with idiopathic pulmonary arterial hypertension (IPAH) who usually have concurrent right heart failure. METHODS: 55 patients with newly diagnosed IPAH were continuously enrolled and serum HE4 levels were assessed at baseline. All patients were followed up from the date of blood sampling, and a composite endpoint of clinical worsening was detailedly recorded. RESULTS: Serum levels of HE4 were significantly higher in IPAH patients than healthy controls (6.9 ± 2.2 vs 4.4 ± 0.9 ng/ml, p < 0.05) and increased as cardiac function deteriorated. HE4 levels correlated with endothelin-1 (r = 0.331, p < 0.01) and right atrial pressure (r = 0.30, p < 0.03). After a mean follow-up of 20 ± 10 months, 13 patients experienced clinical worsening. Receiver operating characteristic analysis showed that HE4 levels > 6.5 ng/ml discriminated clinical worsening with a sensitivity of 92.31% and a specificity of 59.52% (area under the curve [AUC] = 0.81). Multivariate Cox regression analysis demonstrated that HE4 (χ2: 5.10; hazard ratio [HR] = 1.26; 95% confidence interval: 1.03 to 1.55, p < 0.02) and pulmonary vascular resistance (χ 2: 4.19; HR = 1.14; 95% confidence interval: 1.00-1.29, p < 0.04) were independently predictive of clinical worsening. Patients with HE4 > 6.5 ng/ml had a worse 2-year survival rate than those with HE4 ≤ 6.5 ng/ml (58.9% vs 96.2%, p < 0.001). CONCLUSIONS: Serum levels of HE4 were elevated in IPAH patients and correlated with disease severity. HE4 was an independent predictor of clinical worsening in IPAH patients.

Glutaminyl cyclase inhibitor contributes to the regulation of HSP70, HSP90, actin, and ribosome on gene and protein levels in vitro.

Because of the crucial roles of upregulated glutaminyl cyclase (QC) in the initiation and development of Alzheimer's disease (AD), QC inhibitors are supposed as disease-modifying agents for the treatment of AD. And reported compounds encourage this hypothesis greatly based on the remarkable anti-AD effects in vivo. To illustrate the mechanism in detail, the actions of a selected QC inhibitor (23) were assessed firstly in a cell system here. It was demonstrated that QC activities and the generation of pyroglutamate-modified ß-amyloids in PC12 cells were both inhibited obviously after the treatment of 23. A total of 13 and 15 genes were up- and downregulated significantly in treated cells by RNA-sequencing analysis. Quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, WB, and immunofluorescence analysis supported the effects of 23 on the transcriptome of PC12 cells consequently. The expressions of chaperones, heat shock proteins (HSP) 70, and 90, were upreglutated, while gene expression of actin and the level of encoded protein were reduced significantly in PC12 cells with the treatment. Furthermore, the regulations of ribosome were observed after the treatment. These results indicate the potency of 23 to improve the translation, expression and folding regulation of proteins and affect the multivalent cross-linking of cytoskeletal protein and other proteins subsequently in the cell system and might contribute to the understanding of the mechanism of QC inhibitor as potential anti-AD agents.