A Complete Unveiling of the Mechanism and Chirality in Photoisomerization of Arylazopyrazole 3pzH: Combined Electronic Structure Calculations and AIMS Dynamic Simulations.

The arylazopyrazole 3pzH as a novel photoswitch exhibits quantitative switching and high thermal stability. In this work, combined electronic structure calculations and ab initio multiple spawning (AIMS) dynamic simulations were performed to systemically investigate the cis ↔ trans photoisomerization mechanism and the chiral preference after photoexcitation of 3pzH to the first excited singlet state (S1). Unlike most of the azoheteroarene photoswitches reported previously, many twisted and T-shaped cis isomers were found to be stable for 3pzH in the S0 state, owing to the moderate interaction between the hydrogen atom and π electrons of the aromatic ring. Two twisted cis isomers with different chirality ((M)-Z1 and (P)-Z1), the most stable T-shaped cis isomer ((T)-Z2), and the most stable planar trans isomer (E2) were selected as the initial structures to carry out the AIMS nonadiabatic dynamic simulations. Following excitation to the S1 state, all of the cis isomers decayed to conical intersection (CI) regions via the same bicycle pedal mechanism, while the evolution of the trans isomers to their CI regions was achieved via rotation around the N═N bond. More importantly, chiral preferences were found for the twisted cis isomers in the S1 state through the AIMS dynamic simulations due to the steric effect and static electronic repulsion. Notably, chirality was also observed in S1 isomerization starting from the planar E2 isomer because of the dynamic effect. After the nonadiabatic transition to the S0 state, the bicycle pedal mechanism was found to play a crucial role in cis ↔ trans photoisomerization. The simulated photoisomerization productivities were generally consistent with past experimental observations. Our calculations not only uncover the underlying reason for the excellent photoswitching properties of 3pzH but also enrich the knowledge of photoisomerization for azoheteroarene photoswitches, which will surely benefit their rational design.

Photo-dissociation mechanism of trifluoroacetyl chloride in the gas phase: AIMS dynamic simulations.

In this article, the structures and energies of CF3COCl in the low-lying electronic states have been determined by SA-2-CAS(8,7)/6-31G* and SA-2-MSPT2(8,7)/6-31G* calculations, which include equilibrium geometries, transition states, and three minimum-energy conical intersections (CI-1, CI-2, and CI-3) between S0 and S1 states. The AIMS method was used to carry out non-adiabatic dynamic simulations with the ab initio calculation performed at the SA-2-CAS(8,7)/6-31G* level. Upon irradiation to the S1 state, CF3COCl first relaxes to S1 minimum and then overcomes the ∼10 kcal/mol (TSS1_CCl) or ∼30 kcal/mol (TSS1_CO) barrier to the conical intersection region CI-1 or CI-3 (minor), with the S1 → S0 transition probability of 63:1. After non-adiabatic transition to the S0 state through CI-1, trajectories mainly distribute to three different reaction pathways, with one going back to S0 minimum through shortening of the C-Cl bond, the other forming CF3CO and Cl radicals by continuous elongation of the C-Cl distance, and another dissociating into CF3 + CO + Cl and running into the CI-3 region through elongation of C-C and C-Cl distances. Moreover, we found that the trajectories would recross to the S1 state with the recrossing probability of 13.9% through the CI-3 region due to the extremely sloped topographic character of CI-3. On the basis of time evolution of wavefunctions simulated here, the product ratio of CF3 + CO + Cl and CF3CO + Cl is 53.5%:18.4%, which is consistent with the experimental value of 3:1. We further explain the photo-dissociation wavelength dependence of CF3COCl, and the product ratio of CF3 + CO + Cl increases with the increase in total energy.

Identifiable biomarker and treatment development using HIV-1 long term non-progressor sera.

BACKGROUND: HIV-infected long-term non-progressor (LTNP) subjects can prevent viral replication and may harbor useful information for the development of both antibody and active vaccination treatments. In this study we used LTNP sera to examine the epitopes presented to the gp160 protein, and from this procedure we hope to elucidate potential biomarkers pertaining to the level of resistance a patient may have in developing AIDS after infection with HIV. We used five clinical sera samples from LTNP patients to identify common epitopes by ELISA; peptides with high binding to sera were selected and analyzed for conservation among HIV clades. Antibodies were generated against one identified epitope using a chimeric peptide in BALB/c mice, and both the sera from these mice and LTNP sera were tested for viral inhibition capabilities. RESULTS: A monoclonal antibody, CL3, against one identified epitope was used to compare these epitopes neutralizing capability. LTNP sera was also studied to determine chemokine/cytokine changes in these patients. The sera from LTNP patients 2, 3, 4, and 5 were identified as having the highest titers, and also significantly inhibited syncytia formation in vitro. Finally, the protein cytokine array demonstrated that I-309 and IGFBP-1 decreased in LTNPs, but levels of TIMP-1 and NAP-2 increased significantly. CONCLUSIONS: Our results indicate that the use of LTNP samples may be a useful for identifying further anti-viral epitopes, and may be a possible predictor for determining if patients show higher resistances of converting the HIV infection to AIDS.

Urinary metabolic profiles during Helicobacter pylori eradication in chronic gastritis.

BACKGROUND: Helicobacter pylori (H. pylori) infection is a major risk factor for chronic gastritis, affecting approximately half of the global population. H. pylori eradication is a popular treatment method for H. pylori-positive chronic gastritis, but its mechanism remains unclear. Urinary metabolomics has been used to elucidate the mechanisms of gastric disease treatment. However, no clinical study has been conducted on urinary metabolomics of chronic gastritis. AIM: To elucidate the urinary metabolic profiles during H. pylori eradication in patients with chronic gastritis. METHODS: We applied LC-MS-based metabolomics and network pharmacology to investigate the relationships between urinary metabolites and H. pylori-positive chronic gastritis via a clinical follow-up study. RESULTS: Our study revealed the different urinary metabolic profiles of H. pylori-positive chronic gastritis before and after H. pylori eradication. The metabolites regulated by H. pylori eradication therapy include cis-aconitic acid, isocitric acid, citric acid, L-tyrosine, L-phenylalanine, L-tryptophan, and hippuric acid, which were involved in four metabolic pathways: (1) Phenylalanine metabolism; (2) phenylalanine, tyrosine, and tryptophan biosynthesis; (3) citrate cycle; and (4) glyoxylate and dicarboxylate metabolism. Integrated metabolomics and network pharmacology revealed that MPO, COMT, TPO, TH, EPX, CMA1, DDC, TPH1, and LPO were the key proteins involved in the biological progress of H. pylori eradication in chronic gastritis. CONCLUSION: Our research provides a new perspective for exploring the significance of urinary metabolites in evaluating the treatment and prognosis of H. pylori-positive chronic gastritis patients.

Dual Functionality of 6-Methylthioguanine: Synergistic Effects Enhancing the Photolability of DNA Nucleobases.

A small chemical modification of the nucleobase structure can significantly enhance the photoactivity of DNA, which may incur DNA damage, thus holding promising applications in photochemotherapy treatment of cancers or pathogens. However, single substitution confers only limited phototoxicity to DNA. Herein, we combine femtosecond and nanosecond time-resolved spectroscopy with high-level ab initio calculations to disentangle the excited-state dynamics of 6-methylthioguanine (me6-TG) under variable wavelength UVA excitation (310-330 nm). We find that double substitution of nucleobases (thionation and methylation) boosts the photoactivity by introducing more reactive channels. Intriguingly, 1nNπ*, rather than 1nSπ*, acts as the doorway state engendering the formation of the long-lived reactive triplet state in me6-TG. The 1nNπ* induces a low spin-orbit coupling of 8.3 cm-1, which increases the intersystem crossing (ISC) time (2.91 ± 0.14 ns). Despite the slowed ISC, the triplet quantum yield (ΦT) still accounts for a large fraction (0.6 ± 0.1), consistent with the potential energy surface that favors excited-state bifurcation to 1nNπ*min (3.36 ± 0.15 ps) rather than 1ππ*min (5.05 ± 0.26 ps), such that the subsequent ISC to triplet via 1nNπ*min constitutes the main relaxation pathway in me6-TG. Although this ΦT is inferior to its single-substituted predecessor 6-thioguanine (6-TG, 0.8 ± 0.2), the effect of thionation in synergy with methylation opens a unique C-S bond cleavage pathway through crossing to a repulsive 1πσ* state, generating thiyl radicals as highly reactive intermediates that may invoke biological damage. This photodissociation channel is extremely difficult for conventional nucleobases. These findings demonstrate the synergistic effects of double functionality substitution in modulating excited-state dynamics and enhancing the photolabile character of DNA nucleobases, providing inspirations for the rational design of advanced photodynamic and photochemotherapy approaches.

Deacetylated-poly-N-acetylglucosamine-folic Acid as a Nanocarrier for Delivering miR-196a Inhibitor to Anticancer Activity.

Background: MiR-196a is particularly noticeable in the development of liver cancer. However, the rapid degradation by ribonuclease (RNase) imposes a limit on the miRNA gene therapy applications. Aims: To design a novel gene-targeting nano system for liver cancer treatment. Study Design: Cell culture study and animal experimentation. Methods: Deacetylated (DEAC)-poly-N-acetylglucosamine (PNAG)-folic acid (FA) was prepared via ethyl (dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide reaction, and miR-196a inhibitor (miR-196a I)/DEAC-PNAG-FA was prepared through self-assembly. The characterization and nucleic acid protection of the self-assembly system were also determined. The biological function and related mechanism of the prepared system were studied at cellular and molecular levels. Mice were established as a xenotransplantation model to evaluate the anticancer capacity of miR-196a I/DEAC-PNAG-FA in vivo. Results: The morphology of miR-196a I/DEAC-PNAG-FA was uniform, and its particle size was approximately 70-100 nm. A nanocarrier with an N/P ratio of 200:1 can maximize the nucleic acid carrying capacity of the self-assembly system. The nanosystem can protect miRNA from RNase degradation and could be internalized rapidly within 4 h. The self-assembly system significantly enhanced the apoptosis-inducing effect of miR-196a I on HepG2 cells (P = 0.003). Molecular biological analyses confirmed that the apoptosis-inducing effect of the nanosystem was due to the inhibition of miR-196a gene expression in HepG2 cells, which upregulate the expression of pro-apoptotic proteins FOXO1 (P < 0.001), Bax (P < 0.001), Ki67 (P < 0.001), and proliferating cell nuclear antigen (P < 0.001), and inhibit the expression of apoptosis inhibitory protein Bcl-2 (P < 0.001). Moreover, compared with free miR-196a inhibitor or miR-196a I/DEAC-PNAG, miR-196a I/DEAC-PNAG-FA can more effectively inhibit tumor growth in vivo (P = 0.026). Conclusion: The newly prepared self-assembly targeting system can effectively induce apoptosis and abrogate tumor growth, which may open a new approach for liver cancer treatment.

Identification of super enhancer-associated key genes for prognosis of germinal center B-cell type diffuse large B-cell lymphoma by integrated analysis.

BACKGROUND: The pathogenesis of germinal center B-cell type diffuse large B-cell lymphoma (GCB-DLBCL) is not fully elucidated. This study aims to explore the regulation of super enhancers (SEs) on GCB-DLBCL by identifying specific SE-target gene. METHODS: Weighted gene co-expression network analysis (WGCNA) was used to screen modules associated with GCB subtype. Functional analysis was performed by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. H3K27ac peaks were used to identify SEs. Overall survival analysis was performed using Kaplan-Meier curve with log-rank and Breslow test. The effect of ADNP, ANKRD28 and RTN4IP1 knockdown on Karpas 422 and SUDHL-4 cells proliferation was analyzed by CCK-8. Karpas 422 and SUDHL-4 cells were treated with bromodomain and extra-terminal domain (BET) inhibitor JQ1, and the expression of ADNP, ANKRD28 and RTN4IP1was measured by qRT-PCR. RESULTS: A total of 26 modules were screened in DLBCL. Turquoise module was closely related to GCB-DLBCL, and its eigengenes were mainly related to autophagy. There were 971 SEs in Karpas 422 cell and 1088 SEs in SUDHL-4 cell. Function of the nearest genes of overall SEs were related to cancer. Six SE-related genes associated with GCB-DLBCL were identified as prognostic markers. Knockdown of ADNP, ANKRD28 and RTN4IP1 inhibited the proliferation of Karpas 422 and SUDHL-4 cells. JQ1 treatment suppressed ADNP, ANKRD28 and RTN4IP1 expression in Karpas 422 and SUDHL-4 cells. CONCLUSIONS: A total of 6 SE-related genes associated with GCB-DLBCL overall survival were identified in this study. These results will serve as a theoretical basis for further study of gene regulation and function of GCB-DLBCL.

Systematic review and meta-analysis of the efficacy of trypsin inhibitors in patients with severe pancreatitis.

BACKGROUND: This study aimed to explore the efficacy of trypsin inhibitors in the treatment of severe pancreatitis (SP) by meta-analysis. METHODS: The Boolean logic retrieval method was adopted to recruit the relevant literature. Chinese and English databases were respectively searched using a combination of the following search terms: "trypsin inhibitor", "acute pancreatitis", and "severe pancreatitis". The trypsin-treated SP group was set as the experimental group, and the blank control was set as the control group. Meta-analysis was performed using RevMan 5.3 software provided by the Cochrane system. RESULTS: A total of 12 references were included. The meta-analysis suggested that the heterogeneity test results of pancreatic infection incidence were Chi2 =0.51, degrees of freedom (df) =7, I2=0%<50%, and P=1.00>0.01, with risk ratio (RR): 0.80, 95% confidence interval (CI): (0.64, 1.01), Z=1.88, and P=0.06. The heterogeneity test results of extra-pancreatic infection incidence were Chi2 =0.20, df =5, I2=0%<50%, and P=1.00>0.01, with RR: 0.81, 95% CI: (0.62, 1.05), Z=1.60, and P=0.11. The heterogeneity test results of the length of hospital stay were Tau2 =65.69, Chi2 =75.05, df =6, I2=92%>50%, and P<0.0001. The length of hospital stay of the experimental group was shorter than that of the control group, with mean difference (MD): -23.31 and the 95% CI: (-29.60, -17.02), and the difference was statistically significant (Z=7.26, P<0.0001). The heterogeneity test results of the inflammatory factor tumor necrosis factor-α (TNF-α) level were Chi2 =67.28, df =3, I2=96%>50%, and P<0.0001. The level of TNF-α in the experimental group was lower than that in the control group, with MD: -11.69, 95% CI: (-12.51, -10.87), and the difference was statistically significant (Z=27.88, P<0.0001). The heterogeneity test results of the mortality rate were Chi2 =2.52, df =5, I2=0%<50%, and P=0.77>0.01. The mortality rate of the experimental group was lower than that of the control group, with RR: 0.27 and 95% CI: (0.19, 0.40), and the difference was notable (Z=6.75, P<0.0001). DISCUSSION: The meta-analysis performed in this study confirmed that trypsin inhibitors can inhibit the release of inflammatory factors and reduce mortality rate of SP patients.

Silencing of karyopherin α2 inhibits cell growth and survival in human hepatocellular carcinoma.

Karyopherin α2 (KPNA2), involved in nucleocytoplasmic transport, has been reported to be upregulated in hepatocellular carcinoma and considered as a biomarker for poor prognosis. However, comprehensive studies of KPNA2 functions in hepatocellular carcinogenesis are still lacking. Our study examine the roles and related molecular mechanisms of KPNA2 in hepatocellular carcinoma development. Results show that KPNA2 knockdown inhibited the proliferation and growth of hepatocellular carcinoma cells in vitro and in vivo. KPNA2 knockdown also inhibited colony formation ability, induced cell cycle arrest and cellular apoptosis in two hepatocellular carcinoma cell lines, HepG2 and SMMC-7721. Furthermore, gene expression microarray analysis in HepG2 cells with KPNA2 knockdown revealed that critical signaling pathways involved in cell proliferation and survival were deregulated. In conclusion, this study provided systematic evidence that KPNA2 was an essential factor promoting hepatocellular carcinoma and unraveled potential molecular pathways and networks underlying KPNA2-induced hepatocellular carcinogenesis.

The effect and mechanism of miR196a in HepG2 cell.

AIM: To explore the role of miR-196a on the regulatory mechanism in hepatocelluar carcinoma. METHODS: The antisense RNA of microRNA-196a was synthesized and cloned into the vector. HepG2 cells were infected by inhibiting miR196a vector. The HepG2 cells were divided into miR196a lower expression group, NC group and N group in vitro. The expression of the targets of miR-196a was detected by qPCR. Cell growth was analyzed by cck8 assay. The invasion was detected by transwell method. Apoptosis was detected by annexinV/PI. The P53, caspase-3, HOXB9, HOXB8 mRNA and their protein was detected by qPCR and Western-blot. RESULTS: (1) The expression level of miR-196a was less than normal (41%). (2) The proliferation of HepG2 was also markedly suppressed in inhibiting miR196a at the 24 h point than normal about 72.29±2.51% (P<0.01). (3) The number of cells that migrated through the chamber of miR196a inhibiting group is less than normal and NC (P<0.01). (4) The cell apoptosis in miR196a inhibiting group is more than NC and normal group (P<0.05). HOXB8 mRNA and protein expression, in HepG2 cell line miR196a inhibiting group is significantly less than normal, NC (P<0.05). Caspase-3 mRNA and protein expression is maximum in three groups (P<0.05). In three groups there was no significant difference in the expression of P53 mRNA and protein and HOXB9mRNA. CONCLUSIONS: Our results demonstrate that miR-196a can effect the proliferation, the apoptosis and migration of HepG2 cell lines by gene HOXB8, caspase-3 regulation. However, there is no correlation between miRNA196a and P53 and HOXB9.

Associations between three common MicroRNA polymorphisms and hepatocellular carcinoma risk in Chinese.

AIM: Associations between polymorphisms in miR-146aG>C, miR-196a2C>T and miR-499A>G and risk of HCC, and interaction with HBV infection in a Chinese population, were the target of the present research. METHODS: The duplex polymerase-chain-reaction with confronting-two-pair primers (PCR-RFLP) was performed to determine the genotypes of the miR-146aG>C, miR-196a2C>T and miR-499A>G genotypes. Associations of polymorphisms with the risk of HCC were estimated by conditional logistic regression analysis. RESULTS: Drinking, family history of cancer, HBsAg and HCV were risk factors for HCC. Multivariate regression analyses showed that subjects carrying the miR-196a2 CC genotype had significantly increased risk of HCC, with an adjusted OR (95% CI) of 2.18 (1.23-3.80). In addition, cases carrying the miR-196a2 C allele had a 1.64-fold increase in the risk for HCC (95%CI=1.03-2.49). The miR-196a CT and TT genotypes greatly significantly increased the risk of HCC in subjects with HBV infection, with adjusted ORs (95% CI) of 2.02 (1.12-3.68) and 2.69 (1.28-5.71), respectively. CONCLUSION: Our results demonstrate that miR-196a2 CC genotype and C allele have an important role in HCC risk in Chinese, especially in patients with HBV infection.

Expression of aquaporin 8 and its relationship with melanosis coli.

BACKGROUND: The relationship between melanosis coli (MC) and aquaporin 8 (AQP8) has not yet been elucidated. The aim of this research was to investigate the relationship between the expression of AQP8 and the pathological mechanism of MC. METHODS: Expression of AQP8 was detected by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) in 37 MC colon tissues and 13 control colon tissues. Global gene expression analysis was also used to identify differently expressed genes. Its relationship with MC was analyzed by SPSS 11.5 statistical software. RESULTS: The positive rate of AQP8 expression detected by immunohistochemistry in the MC group was 24.3% (9/37), significantly lower than the 69.2% (9/13) in the control group (P < 0.05). The relative expression level of AQP8 in MC group was 0.639 ± 0.160, lower than 0.921 ± 0.148 of controls (P < 0.05). Global gene expression analysis showed that AQP8 mRNA expression was downregulated in MC patients. CONCLUSIONS: The decreased AQP8 expression in MC patients indicates that chronic use of laxatives containing anthraquinone may cause reduced water absorption. The expression of AQP8 may be related to MC.