Construction of Zr-Metal-Organic Frameworks-Based Composite Materials toward Anhydrous Proton Conduction and Photocatalytic CO2 Reduction.

Metal-organic frameworks constructed from Zr usually possess excellent chemical and physical stability. Therefore, they have become attractive platforms in various fields. In this work, two families of hybrid materials based on ZrSQU have been designed and synthesized, named Im@ZrSQU and Cu@ZrSQU, respectively. Im@ZrSQU was prepared through the impregnation method and employed for proton conduction. Im@ZrSQU exhibited terrific proton conduction performance in an anhydrous environment, with the highest proton conduction value of 3.6 × 10-2 S cm-1 at 110 °C. In addition, Cu@ZrSQU was synthesized via the photoinduction method for the photoreduction of CO2, which successfully promoted the conversion of CO2 into CO and achieved the CO generation rate of up to 12.4 µmol g-1 h-1. The photocatalytic performance of Cu@ZrSQU is derived from the synergistic effect of Cu NPs and ZrSQU. Based on an in-depth study and discussion toward ZrSQU, we provide a versatile platform with applications in the field of proton conduction and photocatalysis, which will guide researchers in their further studies.

Rates of treatment-resistant schizophrenia from first-episode cohorts: systematic review and meta-analysis.

BACKGROUND: Treatment-resistant schizophrenia (TRS) is associated with high levels of functional impairment, healthcare usage and societal costs. Cross-sectional studies may overestimate TRS rates because of selection bias. AIMS: We aimed to quantify TRS rates by using first-episode cohorts to improve resource allocation and clozapine access. METHOD: We undertook a systematic review of TRS rates among people with first-episode psychosis and schizophrenia, with a minimum follow-up of 8 weeks. We searched PubMed, PsycINFO, EMBASE, CINAHL and the Cochrane Database of Systematic Reviews, and meta-analysed TRS rates from included studies. RESULTS: Twelve studies were included, totalling 11 958 participants; six studies were of high quality. The rate of TRS was 22.8% (95% CI 19.1-27.0%, P < 0.001) among all first-episode cohorts and 24.4% (95% CI 19.5-30.0%, P < 0.001) among first-episode schizophrenia cohorts. Subgroup sensitivity analyses by location of recruitment, TRS definition, study quality, time of data collection and retrospective versus prospective data collection did not lead to statistically significant differences in heterogeneity. In a meta-regression, duration of follow-up and percentage drop-out did not significantly affect the overall TRS rate. Men were 1.57 times more likely to develop TRS than women (95% CI 1.11-2.21, P = 0.010). CONCLUSIONS: Almost a quarter of people with first-episode psychosis or schizophrenia will develop TRS in the early stages of treatment. When including people with schizophrenia who relapse despite initial response and continuous treatment, rates of TRS may be as high as a third. These high rates of TRS highlight the need for improved access to clozapine and psychosocial supports.

Ag Nanoparticle-Modified Polyoxometalate-Based Metal-Organic Framework for Enhanced CO2 Photoreduction.

The photoreduction deposition method is employed to fabricate a family of silver nanoparticle (Ag NP)-modified polyoxometalate-based metal-organic framework (NENU-5) photocatalysts, named Ag/NENU-5. The title photocatalysts, Ag/NENU-5, can be used for the photocatalytic reduction of CO2 and are observed to efficiently reduce CO2 into CO, in which the highest reduction rate is 22.28 µmol g-1 h-1, 3 times greater than that of NENU-5. Photocatalytic reduction performances of CO2 have been extremely improved after the incorporation of Ag NPs as the cocatalyst. The enhancement of the photocatalytic reduction of CO2 has been attributed to the synergistic effects of Ag NPs and NENU-5, inhibiting the charge recombination during the photocatalytic process and increasing the reaction active sites. Furthermore, the influence of Ag NPs on the photocatalytic activity has also been investigated. The experimental results clearly reveal that the size of Ag NPs could exert a main effect on the photocatalytic activity, and the reasonable size of Ag NPs is able to enhance the photocatalytic reduction activity toward CO2 significantly.

[Effect and mechanism of aspirin combined with vinorelbine on non-small cell lung cancer].

The study aimed to investigate the effect and mechanism of aspirin combined with vinorelbine on the proliferation and apoptosis of non-small cell lung cancer cells. 3-(4-dimethylthiazolyl-2)-2-diphenyltetrazolium bromide(MTT) was used to detect the cytotoxic effect of aspirin and vinorelbine on H460 and A549 cells, and half of inhibitory concentration(IC_(50)) value of drugs as well as synergistic effect were calculated. The results showed that both aspirin and vinorelbine inhibited the cancer cells proliferation by a concentration-dependent manner with IC_(50 )values of 1.553 mmol·L~(-1) and 0.033 µmol·L~(-1) in H460 cells, respectively. The IC_(50 )values of aspirin and vinorelbine were 1.70 mmol·L~(-1)and more than 20 µmol·L~(-1) in A549 cells. The combination index(CI) value was used to evaluate the combined effect of two drugs. Aspirin combined with vinorelbine had synergistic effects at the ratio of 100∶1 on H460 cells and 1∶10 on A549 cells(CI<1). Clone formation and 4',6-diamidino-2-phenylindole(DAPI)/propidium iodide(PI) staining assays were used to verify the effect of the combination of two drugs on proliferation of H460 cells. Compared with the aspirin single group, the combination group had stronger inhibitory effect on the proliferation of H460 cells and the clone formation rate was 49.5%(P<0.05). Furthermore, apoptosis, mitochondrial membrane potential, reactive oxygen species and Western blot experiments were used to explore the synergistic mechanism of aspirin combined with vinorelbine in inhibiting cell proliferation. The results showed that the cancer cell apoptosis rate was 52.8%, the mitochondrial membrane potential was decreased to 33.1%, and the levels of reactive oxygen species was increased to 73.3% in combination group, which were significantly different from those of the single drug treatment groups(P<0.05). Western blot showed that combination group significantly up-regulated the expressions of Bax, p53, cleaved caspase-3 and cytochrome C, while down-regulated the expression of anti-apoptosis proteins such as Bcl-xL and Bcl-2 when compared with single groups. Our results suggested that aspirin combined with vinorelbine could synergistically inhibit the proliferation of H460 cells by inducing the cell apoptosis through the mitochondrial pathway.

Synthesis and evaluation of an injectable everolimus prodrug.

A novel water-soluble everolimus prodrug, glutathione-everolimus, was designed and synthesized by introducing an endogenous tripeptide with an acetyl as the linker. The improvement in water solubility allowed the conjugate to be developed into an injectable drug. The results of biological evaluation in vitro and in vivo suggested that the prodrug was more effective and long acting than everolimus. Meanwhile, the pharmacokinetics study in vivo confirmed that the delivery of everolimus through the injection of the prodrug can overcome the low bioavailability of oral everolimus.

Low toxic and high soluble camptothecin derivative 2-47 effectively induces apoptosis of tumor cells in vitro.

The cytotoxic activity of camptothecin derivatives is so high that these compounds need to be further modified before their successful application as anti-cancer agents clinically. In this study, we reported the synthesis and biological evaluation of a novel camptothecin derivative called compound 2-47. The changes in structure did not reduce its activity to inhibit DNA topoisomerase I. Compound 2-47 induced apoptosis of many tumor cells including leukemia cells K562, Jurkat, HL-60, breast cancer cell BT-549, colon cancer cell HT-29 and liver cancer cell HepG2 with a half maximal inhibitory concentration (IC50) of 2- to 3-fold lower than HCPT as a control. In particular, 2-47 inhibited the proliferation of Jurkat cells with an IC50 of as low as 40 nM. By making use of Jurkat cell as a model, following treatment of Jurkat cells, compound 2-47 activated caspase-3 and PARP, resulting in a decreased Bcl-2/Bax ratio. These data showed that compound 2-47 induces Jurkat cell death through the mitochondrial apoptotic pathway. In addition, compound 2-47 showed a decreased cytotoxic activity against normal cells and an improved solubility in low-polar solvent. For example, compound 2-47 solutes in CHCl3 130-fold higher than HCPT. Taken together, our data demonstrated that camptothecin derivative 2-47 notably inhibits the tumor cell proliferation through mitochondrial-mediated apoptosis in vitro.

Synthesis and antitumor activity evaluation of a novel series of xanthone derivatives.

A natural xanthone, 1,3,6-trihydroxy-5-methoxyxanthone, was totally synthesized for the first time by six steps in 31% overall yield. The xanthone skeleton was formed by a one-step synthesis in 80% yield, and five of its novel derivatives were also obtained by this approach. This synthetic strategy and all the derivatives could be further used for the preparation of other natural xanthones. All the xanthones were characterized by NMR and ESI-MS, and the cytotoxicity of these xanthones was evaluated against HepG2 and HT-29 cells, and the preliminary structure-activity relationship was evaluated from the results. It was proved that the presence of 3-OH group in the molecule is crucial for its biological activity, while the presence of substituents at C-5 and C-6 may also be beneficial.

Synthesis and Biological Evaluation of Novel Water-Soluble Poly-(ethylene glycol)-10-hydroxycamptothecin Conjugates.

In order to improve the antitumor activity and water solubility of 10-hydroxycamptothecin (HCPT), a series of novel HCPT conjugates were designed and synthesized by conjugating polyethylene glycol (PEG) to the 10-hydroxyl group of HCPT via a valine spacer. The in vitro stability of these synthesized compounds was determined in pH 7.4 buffer at 37 °C, and the results showed that they released HCPT at different rates. All the compounds demonstrated significant antitumor activity in vitro against K562, HepG2 and HT-29 cells. Among them, compounds, 4a, 4d, 4e and 4f, exhibited 2-5 times higher potency than HCPT. The stability and antitumor activity of these conjugates were found to be closely related to the length of PEG and the linker type, conjugates with a relatively short PEG chain and carbamate linkages (compounds 4a and 4f) exhibited controlled release of HCPT and excellent antitumor in vitro activity.

5-(2-carboxyethenyl) isatin derivative induces G2/M cell cycle arrest and apoptosis in human leukemia K562 cells.

Our previous study successfully identified that the novel isatin derivative (E)-methyl 3-(1-(4-methoxybenzyl)-2,3-dioxoindolin-5-yl) acrylate (HKL 2H) acts as an anticancer agent at an inhibitory concentration (IC50) level of 3nM. In this study, the molecular mechanism how HKL 2H induces cytotoxic activity in the human chronic myelogenous leukemia K562 cells was investigated. Flow cytometric analysis showed that the cells were arrested in the G2/M phase and accumulated subsequently in the sub-G1 phase in the presence of HKL 2H. HKL 2H treatment down-regulated the expressions of CDK1 and cyclin B but up-regulated the level of phosphorylated CDK1. Annexin-V staining and the classic DNA ladder studies showed that HKL 2H induced the apoptosis of K562 cells. Our study further showed that HKL 2H treatment caused the dissipation of mitochondrial membrane potential, activated caspase-3 and lowered the Bcl-2/Bax ratio in K562 cells, suggesting that the HKL 2H-causing programmed cell death of K562 cells was caused via the mitochondrial apoptotic pathway. Taken together, our data demonstrated that HKL 2H, a 5-(2-carboxyethenyl) isatin derivative, notably induces G2/M cell cycle arrest and mitochondrial-mediated apoptosis in K562 cells, indicating that this compound could be a promising anticancer candidate for further investigation.

Metformin co-commencement at time of antipsychotic initiation for attenuation of weight gain: a systematic review and meta-analysis.

Background: Antipsychotic medications are associated with weight gain and metabolic derangement. However, comprehensive evidence for the efficacy of co-commenced pharmacological treatments to mitigate initial weight gain is limited. Metformin has been shown to be effective in reducing weight among people on antipsychotic medications who are already overweight, but the potential benefits of metformin co-commencement in mitigating antipsychotic-induced weight gain has not been systematically reviewed. Method: We conducted a systematic review of PubMed, EMBASE, PsychInfo, CINAHL, the Cochrane database, and China National Knowledge Infrastructure from inception to 18 November 2023. We undertook a meta-analysis of concomitant commencement of metformin versus placebo for attenuation of weight gain and metabolic syndrome for people with schizophrenia commencing a new antipsychotic. Results: Fourteen studies from Australia, United States, Venezuela, and China with 1126 participants were included. We found that metformin was superior to placebo in terms of attenuating weight gain (-3.12 kg, 95% CI -4.22 to -2.01 kg). Metformin also significantly attenuated derangement of fasting glucose levels, total cholesterol, and total triglyceride levels. Sensitivity analysis on study quality, duration, and antipsychotic agent did not impact the results. Meta-analysis was also conducted on adverse drug reactions (ADR) reported in each study which showed no significant difference in ADR incidence between metformin and placebo groups. Subgroup analysis on antipsychotic-naïve participants and participants switching to new antipsychotic did not impact the results. Conclusion: Metformin led to statistically significant and clinically meaningful attenuation of weight gain as well as attenuation of several other metabolic parameters when commenced concomitantly with antipsychotic medications. Co-commencement of metformin with antipsychotic medications, where tolerated, should be considered in the clinical setting with aim to improve long-term cardiometabolic outcomes for patients with long-term need of antipsychotic treatments.

Synthesis and antitumor activity evaluation of a novel series of camptothecin analogs.

A series of novel 10-substituted camptothecin analogs (3-10) with a carbamate linker were synthesized, and their biological activities were evaluated. The amino acid-linked carbamate derivatives (8-10) of the camptothecin-type natural product not only possessed good to excellent inhibitory activity against three human tumor cell lines K562, HepG2, and HT-29, but also showed significantly less cytotoxicity against normal human cell HEK293 (half maximal inhibiting concentration >10 µM). The selectivity of compound 9 toward tumor cells relative to normal cells is at least 250 times better than that of camptothecin. The preliminary testing result indicated that the solubility of these compounds was also improved compared to that of 10-hydroxy camptothecin.

Podophyllotoxin-loaded PEGylated E-selectin peptide conjugate targeted cancer site to enhance tumor inhibition and reduce side effect.

E-selectin, which is highly expressed in vascular endothelial cells near tumor and get involved in the all tumor growth steps: occurrence, proliferation and metastasis, is considered as a promise targeted protein for antitumor drug discovery. Herein, we would like to report the design, preparation and the anticancer evaluation of the peptide-PEG-podophyllotoxin conjugate(PEG-Pep-PODO), in which the short peptide (CIELLQAR) was used as the E-selectin ligand for the targeting purpose and the PEG portion the molecule got the conjugate self-assembled to form a water soluble nanoparticle. In vitro release study showed that the conjugated and entrapped PODO could be released simultaneously in the presence of GSH (highly expressed in tumor environmental conditions) and the GSH would catalyze the break of the disufur bond which linked of the PODO and the peptide-PEG portion of the conjugate. Cell adhesion test of the PEG-Pep-PODO indicated that E-selectin ligand peptide CIELLQAR could get specifically and efficiently binding to the E-selectin expressing human umbilical vein endothelial cells (HUVEC). In vitro cytotoxicity assay further revealed that PEG-Pep-PODO significantly improved the selectivity of PEG-Pep-PODO for killing the tumor cells and normal cells compared with PODO solution formulation. More importantly, the in vivo experiment demonstrated that the conjugate would accumulate of the PODO payload in tumor through targeting endothelial cells in the tumor microenvironment, which resulted in the much improved in vivo inhibition of tumor growth, intratumoral microvessel density, and decreased systemic toxicity of this nanoparticle over the free PODO. Furthermore, this water soluble conjugate greatly improved the pharmacokinetic properties of the mother molecule.

A porous Ti-based metal-organic framework for CO2 photoreduction and imidazole-dependent anhydrous proton conduction.

The anhydrous proton conductivity of Im@IEF-11 resulting from the integration of imidazole and porous IEF-11 has been investigated, and the highest proton conductive value can reach up to 7.64 × 10-2 S cm-1. Furthermore, IEF-11 is also developed to reduce CO2 due to its reasonable structure and suitable energy band, and its CO formation rate is 31.86 µmol g-1 h-1.

Design, synthesis and anti-NASH effect evaluation of novel GFT505 derivatives in vitro and in vivo.

Non-alcoholic fatty liver disease (NAFLD) is emerging as the largest burden of chronic liver disease worldwide. Nonalcoholic steatohepatitis (NASH) is a progressive form of NAFLD that can progress to cirrhosis and hepatocellular carcinoma. Unfortunately, current treatment options for NASH are very limited. Among the multiple pathways of NASH, peroxisome proliferators-activated receptors (PPARS) are recognized as an important and effective target. GFT 505 is a dual excitement agent for the treatment of PPAR-α/δ for the treatment of NASH. However, its activity and toxicity need to be further improved. Therefore, here we would like to report the design, synthesis and biological evaluation of 11 GFT 505 derivatives. The initial cytotoxicity through proliferation activity of HepG2 cells and in vitro anti-NASH activity evaluation demonstrated that under the same concentration, the compound 3d possess significantly lower cytotoxicity and better anti-NASH activity than that of GFT 505. Moreover, Molecular docking also shows that 3d and PPAR-α/δ can form a stable hydrogen bond and have the lowest binding energy. Therefore this novel molecule 3d was selected to go further in vivo investigation. Methionine-choline deficiency (MCD) induced C57BL/6J NASH model mice was used for the in vivo biological experiments and the compound 3d demostrated lower liver toxicity than that of GFT 505 in the body at the same dose, and it did more effectively improve hyperlipidemia, liver fat degeneration and liver inflammation as well as significantly enhance the content of the GSH which is inportant for the liver protection. This study suggested that the compound 3d is a very promising lead compound for the treatment of NASH.

Pegmolesatide for the treatment of anemia in patients undergoing dialysis: a randomized clinical trial.

Background: Pegmolesatide, a synthetic peptide-based erythropoietin (EPO) receptor agonist, is being evaluated as an alternative to epoetin alfa for treating anemia of chronic kidney disease (CKD) in Chinese dialysis patients. There is a critical need for a long-acting, cost-effective erythropoiesis-stimulating agent that does not produce EPO antibodies. Methods: A randomized, open-label, active-comparator, non-inferiority phase three trial was conducted at 43 dialysis centers in China between May 17th, 2019, and March 28th, 2022. Eligible patients aged 18-70 years were randomly assigned (2:1) to receive pegmolesatide once every four weeks or epoetin alfa one to three times per week, with doses adjusted to maintain a hemoglobin level between 10.0 and 12.0 g/dL. The primary efficacy endpoint was the mean change in hemoglobin level from baseline to the efficacy evaluation period in the per-protocol set (PPS) population. Non-inferiority of pegmolesatide to epoetin alfa was established if the lower limit of the two-sided 95% confidence interval for the between-group difference was ≥ -1.0 g/dL. Safety assessment included adverse events and potential anaphylaxis reactions. This trial is registered at ClinicalTrials.gov, NCT03902691. Findings: Three hundreds and seventy-two patients were randomly assigned to the pegmolesatide group (248 patients) or the epoetin alfa group (124 patients). A total of 347 patients (233 in the pegmolesatide group and 114 in the epoetin alfa group) were included in the PPS population. In the PPS, the mean change (standard deviation, SD) in hemoglobin level from baseline to the efficacy evaluation period was 0.07 (0.92) g/dL in the pegmolesatide group and -0.22 (0.97) g/dL in the epoetin alfa group. The between-group difference was 0.29 g/dL (95% confidence interval: 0.11-0.47), verifying non-inferiority of pegmolesatide to epoetin alfa. Adverse events occurred in 231 (94%) participants in the pegmolesatide group and in 110 (89%) in the epoetin alfa group. Hypertension was the most common treatment-related adverse event. No fatal cases of anaphylaxis or hypotension were reported. Interpretation: Monthly subcutaneously injection of pegmolesatide was as effective and safe as conventional epoetin alfa administrated one to three times a week in treating anemia in Chinese dialysis patients. Funding: The study was supported by Hansoh Medical Development Group.

A Shortcut to the Optimization of Cellulase Production Using the Mutant Trichoderma reesei YC-108.

Trichoderma reesei YC-108, a strain isolated by a kind of newly invented plate was found to over produce cellulase and it was then used as a cellulase producer. To get the maximum amount of cellulase, the combination of the medium ingredients, which has a profound influence on metabolic pathway was optimized using response surface methodology. The optimum composition was found to be 24.63 g/L wheat bran, 30.78 g/L avicel, and 19.16 g/L soya-bean cake powder. By using the optimized medium, the filter paper activity (FPA) increased nearly five times to 15.82 IU/mL in a 30 L stirred fermenter, carboxymethyl cellulase activity (CMCase) was increased from 83.02 to 628.05 IU/mL and the CMCase/FPA ratio was nearly doubled compared with the parent strain at initial medium.

A multifunctional anionic metal-organic framework for high proton conductivity and photoreduction of CO2 induced by cation exchange.

Metal-organic frameworks (MOFs) provide an ideal platform for loading various guests owing to their available space, and can be developed as a class of multifunctional materials. Herein, we cover the design and synthesis of two kinds of exchanged frameworks with multifunctional applications based on H3ImDC and In(NO3)3·2H2O through guest exchange inside the framework. The guest ammonium ion (NH4+) and [Ru(2,2'-bipyridine)3]2+ (Rubpy) are selected to exchange the dimethylammonium cation (Me2NH2+) encapsulated within In-MOF, giving birth to two kinds of new MOFs, named NH4+@In-MOF and Rubpy@In-MOF respectively. The proton conduction of NH4+@In-MOF and the CO2 photoreduction of Rubpy@In-MOF are investigated. Under different test conditions, the proton conductive behaviors of NH4+@In-MOF are evaluated and the best proton conductive value can reach up to 9.81 × 10-3 S cm-1. Compared to the original In-MOF, Rubpy@In-MOF exhibits a significantly enhanced CO2 photoreduction performance under a pure CO2 atmosphere. Furthermore, its photocatalytic activity is retained even under a 10% CO2 gas atmosphere, displaying a synergistic effect between Rubpy and In-MOF24 within Rubpy@In-MOF.

Comparison of 24×20 mm2 swept-source OCTA and fluorescein angiography for the evaluation of lesions in diabetic retinopathy.

AIM: To compare ultra-widefield (24×20 mm2) swept-source optical coherence tomography angiography (SS-OCTA) and fluorescein angiography (FA) in the evaluation of diabetic retinopathy (DR) lesions. METHODS: Forty-six eyes of 23 patients with treatment-naïve DR were included at Peking University People's Hospital from September 1, 2021, until December 31, 2021, as well as 23 age and gender matched healthy controls. Quantitative assessments of DR lesions on FA and SS-OCTA (superficial capillary plexus, SCP, 24×20 mm2) were performed. RESULTS: Area of fovea avascular zone (FAZ) was larger in DR cases than controls (0.34±0.069 mm2 vs 0.287±0.108 mm2, P=0.006). In DR eyes, the mean FAZ area was 0.34±0.069 and 0.334±0.087 mm2 on SS-OCTA and FA, respectively (P=0.428), while the median FAZ perimeter was 2.382 (IQR, 2.201-2.59) and 2.333 (IQR, 2.138-2.6) mm on SS-OCTA and FA images (P=0.733). There was no significant difference in the size of the non-perfusion area (NPA) between the images on SS-OCTA and FA (12.389, IQR 4.96-28.3 and 11.125, IQR 5-28.31 mm2, P=0.197). The median total microaneurysm (MA) count was 35 (IQR, 19-46) and 73 (IQR, 43-93) on SS-OCTA and FA (P<0.001), respectively. No significant difference in intra-retinal microvascular abnormality (IRMA) and neovascularization (NV) count was found between the two techniques. The intraclass coefficient (ICCs) of all the parameters above indicated stable repeatability. CONCLUSION: Ultra-widefield SS-OCTA represents a reliable, noninvasive, and quantitative imaging technique in the assessment of microvasculature in DR, which offers a potential substitute for FA in DR evaluation.

An Insertion Variant in CRH Confers an Increased Risk of Central Serous Chorioretinopathy.

Purpose: To identify a novel corticotropin-releasing hormone (CRH) gene variant relevant in patients with central serous chorioretinopathy (CSC). Methods: We performed a genetic study of CSC in families and sporadic cases with controls. Using whole-exome sequencing and linkage analysis, we identified a heterozygous insertion variant, Gln52insPro, in the CRH gene that cosegregated in two Chinese families with CSC. This variant was evaluated among an additional 1307 patients with CSC and 1438 ethnicity-matched control individuals from three independent Chinese cohorts. Results: The CRH variant was strongly associated with CSC in these cohorts of Chinese patients (Pmeta = 1.24 × 10-11; odds ratio, 3.01; 95% confidence interval, 2.15-4.21). The risk variant Gln52insPro decreased CRH gene expression. Conclusions: Our results implicate the hypothalamic-pituitary-adrenal stress response system in the pathogenesis of CSC and provide a novel rationale for therapeutic intervention.

Akt/Nox2/NF-κB signaling pathway is involved in Tat-induced HIV-1 long terminal repeat (LTR) transactivation.

Human immunodeficiency virus (HIV) regulatory protein Tat has pro-oxidant property, which might contribute to Tat-induced long terminal repeat region (LTR) transactivation. However, the intracellular mechanisms whereby Tat triggers ROS production, and the relationship between Tat-induced ROS production and LTR transactivation, are still subject to debate. The present study was undertaken to evaluate the specific effects of Tat on nicotinamide adenine denucleotide phosphate (NADPH) oxidase in MAGI cells, and to determine the specific role of NADPH oxidase in Tat-induced LTR transactivation. Application of Tat to MAGI cells caused increases in ROS formation that were prevented by both pharmacologic NADPH oxidase inhibitors and by siRNA Nox2, but not by other inhibitors of pro-oxidant enzymes or siRNA Nox4. Furthermore, inhibition of NADPH oxidase by both pharmacologic NADPH oxidase inhibitors and by siRNA Nox2 attenuated Tat-induced p65 phosphorylation and IKK phosphorylation. Phosphatidylinositol 3-kinase/Akt signaling pathway was involved in Tat-induced NADPH oxidase stimulation. Finally, NADPH oxidase inhibitors or Nox2 siRNA, but not control siRNA, inhibited Tat-induced LTR transactivation. Tat-induced HIV-1 LTR transactivation was inhibited in wortmannin or LY294002 treated cells compared to control cells. Together, these data describe a specific and biologically significant signaling component of the MAGI cells response to Tat, and suggest the PI3K/Akt signaling pathway might originate in part with Tat-induced activation of NADPH oxidase and LTR transactivation.