Visible-Light Mediated Deoxygenation of Carboxylic Acid for Late-Stage Peptide Modification Targeting Dehydroalanine.

A visible-light mediated deoxygenative radical addition of carboxylic acids to dehydroalanines has been disclosed. The method can be used in ß-acyl alanine derivative synthesis, including those chiral and deuterated variants, and late-stage peptide modification with various functional groups, both in the homogeneous phase and on the resin in SPPS. It provides a new tool kit for rapid construction of bioactive peptide analogues, which has been demonstrated by modification of the antimicrobial peptide Feleucin-K3.

The novel peptide DR4penA attenuates the bleomycin- and paraquat-induced pulmonary fibrosis by suppressing the TGF-ß/Smad signaling pathway.

Pulmonary fibrosis (PF), which is caused by continuous alveolar epithelial cell injury and abnormal repair, is referred to as a difficult disease of the lung system by the World Health Organization due to its rapid progression, poor prognosis, and high mortality rate. However, there is still a lack of ideal therapeutic strategies. The peptide DR8 (DHNNPQIR-NH2 ), which is derived from rapeseed, exerted antifibrotic activity in the lung, liver, and kidney in our previous studies. By studying the structure-activity relationship and rational design, we introduced an unnatural hydrophobic amino acid (α-(4-pentenyl)-Ala) into DR8 and screened the novel peptide DR4penA (DHNα-(4-pentenyl)-APQIR-NH2 ), which had higher anti-PF activity, higher antioxidant activity and a longer half-life than DR8. Notably, DR4penA attenuated bleomycin- and paraquat-induced PF, and the anti-PF activity of DR4penA was equivalent to that of pirfenidone. Additionally, DR4penA suppressed the TGF-ß/Smad pathway in TGF-ß1-induced A549 cells and paraquat-induced rats. This study demonstrates that the novel peptide DR4penA is a potential candidate compound for PF therapy, and its antifibrotic activity in different preclinical models of PF provides a theoretical basis for further study.

DR7dA, a Novel Antioxidant Peptide Analog, Demonstrates Antifibrotic Activity in Pulmonary Fibrosis In Vivo and In Vitro.

Pulmonary fibrosis (PF), which is characterized by enhanced extracellular matrix (ECM) deposition, is an interstitial lung disease that lacks an ideal clinical treatment strategy. It has an extremely poor prognosis, with an average survival of 3-5 years after diagnosis. Our previous studies have shown that the antioxidant peptide DR8 (DHNNPQIR-NH2), which is extracted and purified from rapeseed, can alleviate PF and renal fibrosis. However, natural peptides are easily degraded by proteases in vivo, which limits their potency. We have since synthesized a series of DR8 analogs based on amino acid scanning substitution. DR7dA [DHNNPQ (D-alanine) R-NH2] is an analog of DR8 in which L-isoleucine (L-Ile) is replaced with D-alanine (D-Ala), and its half-life is better than that of DR8. In the current study, we verified that DR7dA ameliorated tumor growth factor (TGF)-ß1-induced fibrogenesis and bleomycin-induced PF. The results indicated that DR7dA reduced the protein and mRNA levels of TGF-ß1 target genes in TGF-ß1-induced models. Surprisingly, DR7dA blocked fibrosis in a lower concentration range than DR8 in cells. In addition, DR7dA ameliorated tissue pathologic changes and ECM accumulation in mice. BLM caused severe oxidative damage, but administration of DR7dA reduced oxidative stress and restored antioxidant defense. Mechanistic studies suggested that DR7dA inhibits ERK, P38, and JNK phosphorylation in vivo and in vitro All results indicated that DR7dA attenuated PF by inhibiting ECM deposition and oxidative stress via blockade of the mitogen-activated protein kinase (MAPK) pathway. Hence, compared with its parent peptide, DR7dA has higher druggability and could be a candidate compound for PF treatment in the future. SIGNIFICANCE STATEMENT: In order to improve druggability of DR8, we investigated the structure-activity relationship of it and replaced the L-isoleucine with D-alanine. We found that the stability and antifibrotic activity of DR7dA were significantly improved than DR8, as well as DR7dA significantly attenuated tumor growth factor (TGF)-ß1-induced fibrogenesis and ameliorated bleomycin-induced fibrosis by inhibiting extracellular matrix deposition and oxidative stress via blockade of the MAPK pathway, suggesting DR7dA may be a promising candidate compound for the treatment of PF.

HUWE1 mediates inflammasome activation and promotes host defense against bacterial infection.

The mechanism by which inflammasome activation is modulated remains unclear. In this study, we identified an AIM2-interacting protein, the E3 ubiquitin ligase HUWE1, which was also found to interact with NLRP3 and NLRC4 through the HIN domain of AIM2 and the NACHT domains of NLRP3 and NLRC4. The BH3 domain of HUWE1 was important for its interaction with NLRP3, AIM2, and NLRC4. Caspase-1 maturation, IL-1ß release, and pyroptosis were reduced in Huwe1-deficient bone marrow-derived macrophages (BMDMs) compared with WT BMDMs in response to stimuli to induce NLRP3, NLRC4, and AIM2 inflammasome activation. Furthermore, the activation of NLRP3, NLRC4, and AIM2 inflammasomes in both mouse and human cells was remarkably reduced by treatment with the HUWE1 inhibitor BI8622. HUWE1 mediated the K27-linked polyubiquitination of AIM2, NLRP3, and NLRC4, which led to inflammasome assembly, ASC speck formation, and sustained caspase-1 activation. Huwe1-deficient mice had an increased bacterial burden and decreased caspase-1 activation and IL-1ß production upon Salmonella, Francisella, or Acinetobacter baumannii infection. Our study provides insights into the mechanisms of inflammasome activation as well as a potential therapeutic target against bacterial infection.

Effect of bortezomib on proliferation and apoptosis of myeloma cells by activating Wnt/ß-catenin signaling pathway.

Effect of bortezomib on proliferation and apoptosis of myeloma cells by activating Wnt/ß-catenin signaling pathway was investigated. Myeloma cells RPMI-8226 treated with different concentrations of bortezomib were used as experimental groups, and the untreated cells were used as the control group. The proliferation and apoptosis in all groups of cells were detected, as well as the expression levels of Wnt/ß-catenin signaling pathway-related proteins, ß-catenin and c-Myc. The results revealed that bortezomib could inhibit the proliferation of myeloma cells. The apoptotic rates of RPMI-8226 cells in the groups treated with 20, 50 and 80 nmol/l of bortezomib were 12.08±0.61, 35.97±3.11 and 57.22±5.47%, respectively, which were significantly higher than that in the control group (8.28±0.39%) (P<0.05). The expression levels of ß-catenin and c-Myc in the experimental groups were significantly lower than those in the control group (P<0.05). Bortezomib can reduce the expression level of Wnt/ß-catenin signaling pathway-related proteins, ß-catenin and c-Myc, and may inhibit cell proliferation and accelerate apoptosis by activating the Wnt/ß-catenin signaling pathway.

Efficacy of abiraterone combined with flutamide on prostate cancer patients and its effect on serum miR-493-5p and miR-195-5p.

Efficacy of abiraterone combined with flutamide on patients with prostate cancer (PCa) and its effect on levels of miR-493-5p and miR-195-5p contained in serum were investigated. The medical records of 146 PCa patients admitted to Longhua Hospital Shanghai University of Traditional Chinese Medicine from January 2011 to December 2013 were selected. Eighty-four patients were treated with abiraterone combined with flutamide as a study group, 62 patients were treated with abiraterone alone as a control group. The curative effect, adverse reactions, quality of life and five-year overall survival (OS) of the two groups were compared. The serum prostate-specific antigen (PSA) level was measured by radioimmunoassay at 3 days (T1) before treatment, 1 month (T2), 2 months (T3), and 6 months (T4) after treatment, and the relative expression of miR-493-5p and miR-195-5p in serum were detected by qRT-PCR. The total effective rate of the study group was significantly higher than that of the control group (P<0.05). The total incidence of toxic and side effects in the study group was significantly lower than that in the control group (P<0.05). The improvement rate of quality of life in the study group was significantly higher than that in the control group (P<0.05). OS in the study group was significantly higher than that in the control group at 5 years (P<0.05). There was no significant difference in serum PSA level between the two groups at T1 (P>0.05); there was no significant difference in the relative expression of miR-493-5p and miR-195-5p between the two groups at T1 (P>0.05). In conclusion, abiraterone combined with flutamide has better curative effect and lower incidence of adverse reactions in patients with metastatic castration-resistant PCa (CRPC) than abiraterone alone, and can increase the expression levels of miR-493-5p and miR-195-5p in patient serum.

Water Absorption and Hygrothermal Aging Behavior of Wood-Polypropylene Composites.

Environmentally sound composites reinforced with natural fibers or particles interest many researchers and engineers due to their great potential to substitute the traditional composites reinforced with glass fibers. However, the sensitivity of natural fiber-reinforced composites to water has limited their applications. In this paper, wood powder-reinforced polypropylene composites (WPCs) with various wood content were prepared and subjected to water absorption tests to study the water absorption procedure and the effect of water absorbed in the specimens on the mechanical properties. Water soaking tests were carried out by immersion of composite specimens in a container of distilled water maintained at three different temperatures, 23, 60 and 80 °C. The results showed that the moisture absorption content was related to wood powder percentage and they had a positive relationship. The transfer process of water molecules in the sample was found to follow the Fickian model and the diffusion constant increased with elevated water temperature. In addition, tensile and bending tests of both dry and wet composite samples were conducted and the results indicated that water absorbed in composite specimens degraded their mechanical properties. The tensile strength and modulus of the composites reinforced with 15, 30, 45 wt % wood powder decreased by 5.79%, 17.2%, 32.06% and 25.31%, 33.6%, 47.3% respectively, compared with their corresponding dry specimens. The flexural strength and modulus of the composite samples exhibited a similar result. Furthermore, dynamic mechanical analysis (DMA) also confirmed that the detrimental effect of water molecules on the composite specimens.

Meta-analysis of modified Stoppa approach and ilioinguinal approach in anterior pelvic ring and acetabular fractures.

BACKGROUND: The purpose of this meta-analysis was to compare the efficacy of the modified Stoppa approach (MSA) and ilioinguinal approach (IA) in the treatment of anterior pelvic ring and acetabular fractures. METHODS: A literature search was conducted using PubMed, Embase, and Cochrane database for articles that compared MSA and IA in the treatment of anterior pelvic ring and acetabular fractures. All the included articles were evaluated by 2 trained reviewers in accordance with the Cochrane Collaboration Handbook for potential risk. The Jadad decision algorithm and Downs and Black scores were also used to assess the quality of the included studies. The extracted data included operative time, intraoperative blood loss, reduction quality, clinical outcome, and complications. RESULTS: Five articles were included in this meta-analysis, with 186 patients in the MSA group and 219 patients in the IA group. Compared with IA, MSA significantly shortened the operative time (P = .0002), decreased intraoperative blood loss (P = .002), and provided better reduction quality (P = .03). Meanwhile, this meta-analysis suggests no significant difference between MSA and IA regarding clinical outcomes (P = .63) and complications (P = .34). The subgroup analysis of complications also showed no statistically significant difference between the 2 groups (including infection, and vascular and nerve injuries). CONCLUSION: According to this meta-analysis, the currently available evidence suggests that MSA can significantly shorten operative time, decrease intraoperative blood loss, and provide better reduction quality than IA in the treatment of anterior pelvic ring and acetabular fractures. In addition, in terms of clinical outcomes and complications, no significant differences were found between the 2 groups. LEVEL OF EVIDENCE: Level IV, meta-analysis.

Enhanced cell selectivity of hybrid peptides with potential antimicrobial activity and immunomodulatory effect.

BACKGROUND: Hybridization is a useful strategy to bond the advantages of different peptides into novel constructions. We designed a series of AMPs based on the structures of a synthetic AMP KFA3 and a naturally-occurred host defense peptide substance P (SP) to obtain peptides retaining the high antibacterial activity of KFA3 and the immunomodulatory activity and low cytotoxicity of SP. METHODS: Two repeats of KFA and different C terminal fragments of SP were hybridized, generating a series of novel AMPs (KFSP1-8). The antibacterial activities, host cell toxicity and immunomodulation were measured. The antibacterial mechanisms were investigated. RESULTS: Hybrid peptides KFSP1-4 exerted substantial antibacterial activities against Gram-negative bacteria of standard strains and clinical drug-resistant isolates including E.coli, A.baumannii and P.aeruginosa, while showing little toxicity towards host cells. Compared with KFA3, moderate reduction in α-helix content and the interruption in α-helix continuality were indicated in CD spectra analysis and secondary-structure simulation in these peptides. Membrane permeabilization combined with time-kill studies and FITC-labeled imaging, indicated a selective membrane interaction of KFSP1 with bacteria cell membranes. By specially activating NK1 receptor, the hybrid peptides kept the ability of SP to induce intracellular calcium release and ERK1/2 phosphorylation, but unable to stimulate NF-κB phosphorylation. KFSP1 facilitated the survival of mouse macrophage RAW264.7, directly interacting with LPS and inhibiting the LPS-induced NF-κB phosphorylation and TNF-α expression. CONCLUSION: Hybridization is a useful strategy to bond the advantages of different peptides. KFSP1 and its analogs are worth of advanced efforts to explore their potential applications as novel antimicrobial agents.

Effect of Temperature and Strain Rate on the Flexural Behavior of Wood-Polypropylene Composites.

The mechanical properties of wood-polypropylene composites exhibit typical viscoelasticity. However, there is little information on the mechanical properties of wood-polypropylene composites related to temperature and time, which limits the use of wood-polypropylene composites as structural components. Here, the effect of time (strain rate) and temperature on the flexural properties and the master curve of the storage modulus used to predict the long-term performance of wood-polypropylene composites were investigated. The results showed that the flexural strength and modulus increased linearly with the increase of wood contend, which can increase by 134% and 257% respectively when the mass fraction of wood powder reached 45%. Moreover, there was a positive linear relationship between flexural strength and ln strain rate, while the flexural strength and modulus decreased as temperature elevated. The storage modulus as a function of frequency (time) and temperature confirmed this trend. To evaluate the long-term performance, the storage modulus master curve was constructed and the respective activation energy was calculated, which revealed that the long-term performance of the samples depended on the matrix and the addition of an appropriate amount of wood powder was beneficial to improve their durability.

Circ-PRMT5 promotes gastric cancer progression by sponging miR-145 and miR-1304 to upregulate MYC.

Background: Gastric cancer (GC) is a global leading source of cancer-associated deaths. Circular RNAs (circRNAs) are a new type of non-coding RNA and promising biomarkers for diagnosis of multiple diseases such as cancer.Methods: Circ-PRMT5 expression was validated in 90 GC patient tissues and 6 different GC cells by qRT-PCR. Sublocalization of circ-PRMT5 in GC cells was determined in isolated nuclear and cytoplasmic RNAs. CircInteractome and miRanda were used to predict binding sites between circ-PRMT5 with micRNAs, and micRNAs with target mRNA. The correlation between genes was determined by the Pearson correlation analysis. The molecular mechanism was demonstrated by RNA in vivo precipitation, point mutation, luciferase activity and rescue experiments.Results: Circ-PRMT5 expression was significantly higher in GC than in adjacent normal tissues, and GC patients with circ-PRMT5 high expression had shorter survival times. Functionally, circ-PRMT5 silence inhibited GC cell growth and invasion. Mechanism analysis showed that circ-PRMT5 sponged miR-145/miR-1304 to upregulate MYC expression and GC development.Conclusion: Our findings demonstrated that circ-PRMT5 function as an oncogene in GC patients by targeting miR-145/miR-1304/MYC axis. High circ-PRMT5 expression may provide a poor prognostic indicator of survival in GC patients and targeting circ-PRMT5/miR-145/miR-1304/MYC axis may be a novel therapeutic strategy for GC.

Transfection reagent Lipofectamine triggers type I interferon signaling activation in macrophages.

The commercial transfection reagent Lipofectamine has been widely used for cytoplasmic delivery of nucleic acids and for cytosolic engagement with intracellular innate immune sensors to trigger type I interferon (IFN) production. However, the effect of Lipofectamine alone on type I IFN response has not been studied in detail. Here, we show that Lipofectamine induced type I IFN signaling in both RAW 264.7 macrophage-like cells and primary bone marrow-derived macrophages. Type I IFN induction was dependent on interferon regulatory factor (IRF)3 and IRF7 and partially required the toll/interleukin-1 receptor-domain-containing adapter-inducing interferon-ß. In contrast, the transfection reagent Xfect did not activate type I IFN signaling. Our study highlights the potential confounding experimental interpretation when using Lipofectamine-based transfection for delivering intracellular ligands and provides important insights into lipid signaling in innate immune responses.

Structural basis for dimerization of the death effector domain of the F122A mutant of Caspase-8.

Caspase-8 is an apoptotic protease that is activated by a proximity-induced dimerization mechanism within the death-inducing signaling complex (DISC). The death effector domain (DED) of caspase-8 is involved in protein-protein interactions and is essential for the activation. Here, we report two crystal structures of the dimeric DEDs of the F122A mutant of caspase-8, both of which illustrate a novel domain-swapped dimerization, while differ in the relative orientation of the two subunits and the solvent exposure of the conserved hydrophobic patch Phe122/Leu123. We demonstrate that mutations disrupting the dimerization of the DEDs abrogate the formation of cellular death effector filaments (DEFs) and the induced apoptosis by overexpressed DEDs. Furthermore, such dimerization-disrupting mutations also impair the activation of the full-length caspase-8 and the downstream apoptosis cascade. The structures provide new insights into understanding the mechanism underlying the activation of procaspase-8 within the DISC and DEFs.

Influence of enhanced ultraviolet-B radiation during rice plant growth on rice straw decomposition with nitrogen deposition.

Although straw decomposition is important for ecosystem fertility and carbon balance, influence of ultraviolet-B (UV-B) radiation and nitrogen (N) deposition on this process is unclear. In this study, UV-B-exposed rice straw was decomposed under different N addition treatments for 15 months to investigate the indirect effects of UV-B radiation on straw chemistry and direct effects of N deposition on decomposition. UV-B exposure during rice plant growth changed the rice straw chemical composition, increasing the concentrations of acid-insoluble fraction (AIF), acid-soluble fraction, and UV-B-absorbing compounds. High N content had a negative effect on decomposition of rice straw exposed to enhanced and ambient UV-B radiation. Both AIF concentration and FTIR peak intensities indicated that lignin in rice straw was selectively preserved following N addition and UV-B radiation, reducing straw decomposition rate, which corresponded to lower activities of lignin-degrading enzymes in the later stage of decomposition. Thus, enhanced UV-B radiation during rice plant growth produced more recalcitrant substrates (lignin) and N reacted with lignin to produce more resistant compounds, further decreasing straw decomposition rate. UV-B radiation during plant growth and N deposition inhibit litter decomposition in agroecosystem, and their effects should be considered when establishing biogeochemical models in response to global changes.

Quantitative analysis of the cyclic peptide GG-8-6 in rat plasma using LC-MS/MS and its application to a pharmacokinetic study.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide. The discovery of new anticancer compounds is of great significance. GG-8-6, cyclo-(Val1-Leu2-Pro3-Ile4-Leu5-Leu6-Leu7-Val8-Leu9), a new synthetic cyclic peptide, might be a potential candidate for developing new anti-HCC drugs. GG-8-6 shares no structural homology to current anti-HCC drugs. Therefore, it was necessary to develop a quantitative method for the determination of GG-8-6 in vivo. Herein, a simple, specific and sensitive liquid chromatographic method with tandem mass spectrometric detection (LC-MS/MS) was developed and validated for the analysis of GG-8-6 in rat plasma. GG-8-6 and the internal standard (IS), A6, cyclo-(Val1-Leu2-Pro3-Ala4-Leu5-Leu6-Leu7-Val8-Leu9), were extracted from rat plasma by ethyl acetate. Chromatographic separation was performed on an Agilent Eclipse XDB-C18 column (4.6 × 150 mm, 5 µm) with a mobile phase consisting of acetonitrile-water containing 0.1% formic acid (90:10, v/v) with isocratic elution at a flow rate of 0.5 mL/min for 8.0 min. Multiple reaction monitoring (MRM) mode was performed with ion pairs of m/z: 974.8 → 861.8 for GG-8-6 and 932.7 → 819.8 for A6. The selectivity, matrix effects, recovery, intra- and inter-day precision and accuracy were validated with acceptable results in accordance with the US Food and Drug Administration guidelines. The calibration curve was linear (r2 > 0.99) over a concentration range of 1-1000 ng/mL with a lower limit of quantification (LLOQ) of 1 ng/mL. The method was successfully applied to the pharmacokinetic study of GG-8-6 in rats.

[Effects of Biochar Application Rates on Greenhouse Gas Emissions in the Purple Paddy Soil].

In order to explore the effects of different amounts of biochar applied in purple paddy soil on greenhouse gas (GHG) emissions, potted experiments using a static opaque chamber and gas chromatography method were used to study the regulations and influences of biochar on soil greenhouse gas emission using five treatments:no fertilizer (CK), conventional fertilization (NPK), 10 t ·hm-2 biochar+NPK (LBC), 20 t ·hm-2 biochar+NPK (MBC), and 40 t ·hm-2 biochar+NPK (HBC). ① Soil CH4 emission flux reduced significantly with all biochar application treatments; the emission flux followed the order, from large to small, of NPK > CK > LBC > MBC > HBC. The CH4 emission flux of each treatment showed a single peak curve, and the peak value was mainly concentrated in the late growth stage of the paddy cropland. During the entire observation period, the emission flux of CH4 was between -0.05 mg ·(m2 ·h)-1 and 47.34 mg ·(m2 ·h)-1. The CO2 emission flux of each treatment was complicated and ranged from 32.95 mg ·(m2 ·h)-1 to 1350.88 mg ·(m2 ·h)-1. The CO2 emission flux of the LBC and MBC treatments showed bimodal curves, and the CO2 emission flux of other treatments showed single peak curves. In addition, all biochar treatments delayed the peak time of the CO2 emission flux. The N2O emission flux of each treatment ranged from -309.39 to 895.48 µg ·(m2 ·h)-1, and the N2O emission flux of the LBC treatment showed a bimodal curve, while other treatments showed single peak curves. ② Compared with the CK treatment, biochar treatment can significantly reduce the cumulative emissions of CH4 and promote the cumulative emissions of CO2 and N2O. The average amount of CH4 cumulative emissions followed the order CK > LBC > MBC > HBC, while the average amount of CO2 cumulative emissions followed LBC > MBC > HBC > CK, and the average amount of N2O cumulative emissions followed HBC > MBC≈LBC > CK. Compared with conventional fertilization treatment, different application rates of biochar addition significantly reduced CH4 and CO2 emissions. As more biochar was added, CH4 and CO2 cumulative emissions were lower. Although the regulation of N2O cumulative emissions on biochar addition was not obvious, the application of nitrogen fertilizer could promote the emission flux of N2O to some extent. ③ Over the time scale of 100 years, the integrated global warming potentials (GWP) of CH4 and N2O emission under different biochar treatment were decreased significantly, indicating that biochar combined with chemical fertilizer is an effective GHG emission reduction measure.

Smoking, Blood Pressure, and Cardiovascular Disease Mortality in a Large Cohort of Chinese Men with 15 Years Follow-up.

BACKGROUND: To examine the joint effects of smoking and blood pressure on the risk of mortality from cardiovascular disease (CVD) in a cohort of Chinese men. METHODS: This study followed a cohort of 213,221 men over 40 years of age who were recruited from 45 district/counties across China between 1990⁻1991, and whose cause-specific mortality was examined for 15 years, up to 31 December 2005. We calculated hazard ratios for all-cause mortality and CVD, ischemic heart disease (IHD), and stroke mortality for the combined sets of smoking status and blood pressure levels using the Cox proportional hazard model, adjusting for potential individual-level and contextual-level risk factors. RESULTS: During the 15 years of follow-up, 52,795 deaths occurred, including 18,833 deaths from CVD, 3744 deaths from IHD, and 11,288 deaths from stroke. The risk of mortality from CVD, IHD, and stroke increased significantly, with increased systolic blood pressure (SBP), diastolic blood pressure (DBP), and with more pack years of smoking. Compared with never-smokers with normal blood pressure, the hazard ratios and 95% CI of CVD, IHD, and stroke mortality for those who smoked over 20 pack years with hypertension were remarkably increased to 2.30 (95% CI: 2.12⁻2.50), 1.78 (95% CI: 1.48⁻2.14), and 2.74 (95% CI: 2.45⁻3.07), respectively. CONCLUSION: There was a combined effect on the risk of CVD, IHD, and stroke mortality between smoking and hypertension. The joint efforts on smoking cessation and lowered blood pressure should be made to prevent cardiovascular disease mortality in Chinese men.

Salivary factor LTRIN from Aedes aegypti facilitates the transmission of Zika virus by interfering with the lymphotoxin-ß receptor.

Pathogens have co-evolved with mosquitoes to optimize transmission to hosts. Mosquito salivary-gland extract is known to modulate host immune responses and facilitate pathogen transmission, but the underlying molecular mechanisms of this have remained unknown. In this study, we identified and characterized a prominent 15-kilodalton protein, LTRIN, obtained from the salivary glands of the mosquito Aedes aegypti. LTRIN expression was upregulated in blood-fed mosquitoes, and LTRIN facilitated the transmission of Zika virus (ZIKV) and exacerbated its pathogenicity by interfering with signaling through the lymphotoxin-ß receptor (LTßR). Mechanically, LTRIN bound to LTßR and 'preferentially' inhibited signaling via the transcription factor NF-κB and the production of inflammatory cytokines by interfering with the dimerization of LTßR during infection with ZIKV. Furthermore, treatment with antibody to LTRIN inhibited mosquito-mediated infection with ZIKV, and abolishing LTßR potentiated the infectivity of ZIKV both in vitro and in vivo. This study provides deeper insight into the transmission of mosquito-borne diseases in nature and supports the therapeutic potential of inhibiting the action of LTRIN to disrupt ZIKV transmission.

Formulation and statistical optimization of gastric floating alginate/oil/chitosan capsules loading procyanidins: in vitro and in vivo evaluations.

The aim of the present work was to develop gastric floating capsules containing oil-entrapped beads loading procyanidins. The floating beads were prepared by ionotropic gelation method using sodium alginate, CaCl2 and chitosan. The effect of three independent parameters (concentration of sodium alginate, CaCl2 and chitosan) on entrapment efficiency were analyzed by Box-Behnken design. The floating beads were evaluated for surface morphology, particle size, density, entrapment efficiency, buoyancy, release behavior in vitro and floating ability in vivo. The prepared beads were grossly spherical in shape and the mean size was approximately 1.54±0.17mm. The density was 0.97g/cm3. And the optimal conditions were as follows: concentration of sodium alginate, CaCl2 and chitosan were 33.75mg/mL, 9.84mg/mL and 9.05mg/mL, respectively. The optimized formulation showed entrapment efficiency of 88.84±1.04% within small error-value (0.65). The release mechanism of floating capsules followed Korsmeyer-Peppas model (r2=0.9902) with non-Fickian release. The gastric floating capsules exhibited 100% floating percentage in vitro and they could float on the top of gastric juice for 5h in vivo. Therefore, the floating capsules are able to prolong the gastroretentive delivery of procyanidins.

Functional characterization of avidins in amphioxus Branchiostoma japonicum: Evidence for a dual role in biotin-binding and immune response.

Avidin is well known for its high affinity to biotin and has been found in many egg-laying vertebrate species. However, little is known about avidin in invertebrate species to date. Here we clearly showed the presence of two avidin genes, Bjavidin1 and Bjavidin2, in the amphioxus Branchiostoma japonicum, the first ones in non-vertebrate animals. We also showed that the expression of both Bjavidin1 and Bjavidin2 were inducible by progesterone, LTA and LPS. Moreover, we demonstrated for the first time that in addition to biotin-binding, the recombinant proteins rBjAVIDIN1 and rBjAVIDIN2 were not only able to interact with Gram-positive and negative bacteria as well as their conserved surface components LTA and LPS but also to enhance phagocytosis of bacteria by macrophages, suggesting that BjAVIDIN1 and BjAVIDIN2 both function as pattern recognition receptors and opsonins. It is thus clear that avidin may play a dual role in biotin-binding and immune response.