Adaptive Responses of a Peroxidase-like Polyoxometalate-Based Tri-Assembly to Bacterial Microenvironment (BME) Significantly Improved the Anti-Bacterial Effects.

The present study presents the tertiary assembly of a POM, peptide, and biogenic amine, which is a concept to construct new hybrid bio-inorganic materials for antibacterial applications and will help to promote the development of antivirus agents in the future. To achieve this, a Eu-containing polyoxometalate (EuW10) was first co-assembled with a biogenic amine of spermine (Spm), which improved both the luminescence and antibacterial effect of EuW10. Further introduction of a basic peptide from HPV E6, GL-22, induced more extensive enhancements, both of them being attributed to the cooperation and synergistic effects between the constituents, particularly the adaptive responses of assembly to the bacterial microenvironment (BME). Further intrinsic mechanism investigations revealed in detail that the encapsulation of EuW10 in Spm and further GL-22 enhanced the uptake abilities of EuW10 in bacteria, which further improved the ROS generation in BME via the abundant H2O2 involved there and significantly promoted the antibacterial effects.

Synergistically enhanced photothermal transition of a polyoxometalate/peptide assembly improved the antibiofilm and antibacterial activities.

We successfully developed an antimicrobial assembly (Mo154/TK-14) using molybdenum-polyoxometalate and a positively charged peptide of TK-14. It was characterized and assayed using zeta-potential, dynamic light scattering (DLS), and TEM measurements. The Mo154/TK-14 assembly showed an enhanced 808 nm absorption and, therefore, improved the photothermal conversion efficiency of Mo154 (30.3%) to 38.6%. Consequently, in comparison to 5 µM Mo154 without irradiation, both the biofilm formation and bacterial viability of S. aureus were 24.6% and 20.2%, respectively, for the Mo154/TK-14 assembly; the biofilm formation and bacterial viability were further decreased to 7.7% and 4.4% under 808 nm irradiation, respectively. Therefore, the Mo154/TK-14 assembly reflects convincing antibacterial properties compared to Mo154. This is due to the synergistic effect between the peptide-binding enhanced 808 nm absorption and the improved PTT properties. The antimicrobial assembly offers a novel strategy for the rational design of light-responsive antibacterial materials.

In Silico Screening of Novel TMPRSS2 Inhibitors for Treatment of COVID-19.

COVID-19, a pandemic caused by the virus SARS-CoV-2, has spread globally, necessitating the search for antiviral compounds. Transmembrane protease serine 2 (TMPRSS2) is a cell surface protease that plays an essential role in SARS-CoV-2 infection. Therefore, researchers are searching for TMPRSS2 inhibitors that can be used for the treatment of COVID-19. As such, in this study, based on the crystal structure, we targeted the active site of TMPRSS2 for virtual screening of compounds in the FDA database. Then, we screened lumacaftor and ergotamine, which showed strong binding ability, using 100 ns molecular dynamics simulations to study the stability of the protein-ligand binding process, the flexibility of amino acid residues, and the formation of hydrogen bonds. Subsequently, we calculated the binding free energy of the protein-ligand complex by the MM-PBSA method. The results show that lumacaftor and ergotamine interact with residues around the TMPRSS2 active site, and reached equilibrium in the 100 ns molecular dynamics simulations. We think that lumacaftor and ergotamine, which we screened through in silico studies, can effectively inhibit the activity of TMPRSS2. Our findings provide a basis for subsequent in vitro experiments, having important implications for the development of effective anti-COVID-19 drugs.

Transdermal Drug Delivery Systems and Their Use in Obesity Treatment.

Transdermal drug delivery (TDD) has recently emerged as an effective alternative to oral and injection administration because of its less invasiveness, low rejection rate, and excellent ease of administration. TDD has made an important contribution to medical practice such as diabetes, hemorrhoids, arthritis, migraine, and schizophrenia treatment, but has yet to fully achieve its potential in the treatment of obesity. Obesity has reached epidemic proportions globally and posed a significant threat to human health. Various approaches, including oral and injection administration have widely been used in clinical setting for obesity treatment. However, these traditional options remain ineffective and inconvenient, and carry risks of adverse effects. Therefore, alternative and advanced drug delivery strategies with higher efficacy and less toxicity such as TDD are urgently required for obesity treatment. This review summarizes current TDD technology, and the main anti-obesity drug delivery system. This review also provides insights into various anti-obesity drugs under study with a focus on the recent developments of TDD system for enhanced anti-obesity drug delivery. Although most of presented studies stay in animal stage, the application of TDD in anti-obesity drugs would have a significant impact on bringing safe and effective therapies to obese patients in the future.

Correction: Wu, H.; et al. A Purified Aspartic Protease from Akkermansia Muciniphila Plays an Important Role in Degrading Muc2. Int. J. Mol. Sci. 2020, 21, 72.

The authors wish to make the following corrections to this paper [...].

Implications of Gut Microbiota in Complex Human Diseases.

Humans, throughout the life cycle, from birth to death, are accompanied by the presence of gut microbes. Environmental factors, lifestyle, age and other factors can affect the balance of intestinal microbiota and their impact on human health. A large amount of data show that dietary, prebiotics, antibiotics can regulate various diseases through gut microbes. In this review, we focus on the role of gut microbes in the development of metabolic, gastrointestinal, neurological, immune diseases and, cancer. We also discuss the interaction between gut microbes and the host with respect to their beneficial and harmful effects, including their metabolites, microbial enzymes, small molecules and inflammatory molecules. More specifically, we evaluate the potential ability of gut microbes to cure diseases through Fecal Microbial Transplantation (FMT), which is expected to become a new type of clinical strategy for the treatment of various diseases.

Akkermansia muciniphila Aspartic Protease Amuc_1434* Inhibits Human Colorectal Cancer LS174T Cell Viability via TRAIL-Mediated Apoptosis Pathway.

Mucin2 (Muc2) is the main component of the intestinal mucosal layer and is highly expressed in mucous colorectal cancer. Previous studies conducted by our lab found that the recombinant protein Amuc_1434 (expressed in Escherichia coli prokaryote cell system, hereinafter termed Amuc_1434*), derived from Akkermansia muciniphila, can degrade Muc2. Thus, the main objective of this study was to explore the effects of Amuc_1434* on LS174T in colorectal cancer cells expressing Muc2. Results from this study demonstrated that Amuc_1434* inhibited the proliferation of LS174T cells, which was related to its ability to degrade Muc2. Amuc_1434* also blocked the G0/G1 phase of the cell cycle of LS174T cells and upregulated the expression of tumor protein 53 (p53), which is a cell cycle-related protein. In addition, Amuc_1434* promoted apoptosis of LS174T cells and increased mitochondrial ROS levels in LS174T cells. The mitochondrial membrane potential of LS174T cells was also downregulated by Amuc_1434*. Amuc_1434* can activate the death receptor pathway and mitochondrial pathway of apoptosis by upregulating tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL). In conclusion, our study was the first to demonstrate that the protein Amuc_1434* derived from Akkermansia muciniphila suppresses LS174T cell viability via TRAIL-mediated apoptosis pathway.

Boletus aereus protects against acute alcohol-induced liver damage in the C57BL/6 mouse via regulating the oxidative stress-mediated NF-κB pathway.

CONTEXT: Alcoholic liver disease, caused by abuse and consumption of alcohol, exhibits high morbidity and mortality. Boletus aereus Bull. (Boletaceae) (BA) shows antioxidant, anti-inflammatory and antimicrobial effects. OBJECTIVES: To investigate the hepatoprotective effects of BA using an acute alcohol-induced hepatotoxicity mice model. MATERIALS AND METHODS: The composition of BA fruit body was first systematically analyzed. Subsequently, a C57BL/6 mice model of acute alcohol-induced liver injury was established by intragastrically administration of alcohol, which was intragastrically received with BA powder at 200 mg/kg and 800 mg/kg for 2 weeks, 60 mg/kg silybin treatment was used as positive control group. By employing the pathological examination, ELISA, RT-PCR and western blot, the regulation of BA on oxidative stress signals was investigated. RESULTS: The LD50 of BA was much higher than 4 g/kg/p.o. In acute alcohol-damaged mice, BA reduced the levels of alanine aminotransferase (>18.3%) and aspartate aminotransferase (>27.6%) in liver, increased the activity of liver alcohol dehydrogenase (>35.0%) and serum acetaldehyde dehydrogenase (>18.9%). BA increased the activity of superoxide dismutase (>13.4%), glutathione peroxidase (>11.0%) and 800 mg/kg BA strongly reduced chemokine (C-X-C motif) ligand 13 (14.9%) and chitinase-3 like-1 protein (13.4%) in serum. BA reversed mRNA over-expression (>70%) and phosphor-stimulated expression (>45.0%) of an inhibitor of nuclear factor κ-B kinase (NF-κB, an inhibitor of nuclear factor κ-B α and nuclear factor κ-B in the liver. CONCLUSIONS: BA is effective in ameliorating alcohol-induced liver injury through regulating oxidative stress-mediated NF-κB signalling, which provides a scientific basis for further research on its clinical applications.

Screening, Identification, and Characterization of an Affinity Peptide Specific to MT1-MMP and Its Application in Tumor Imaging.

Membrane type-1 matrix metalloproteinase (MT1-MMP) plays a crucial role in many physiological and pathological processes, especially in tumor invasion and metastasis. Bioimaging of this key molecule may find wide usage in various applications. MT-loop is a unique sequence of MT1-MMP and locates in the surface of the protein. In our previous studies, AF7p, an affinity peptide that targeting the MT-loop domain of MT1-MMP, was identified by screening a phage display (Ph.D.) peptide library. However, the target of AF7p is a synthetic sequence which lacked native conformation of the MT-loop region; thus, the binding affinity and specificity in reality may not be optimal. In this study, we considered the 3-dimensional (3-D) conformation of the MT-loop area in the MT1-MMP molecule and designed a novel strategy to screen the Ph.D. peptide library. The peptide we obtained showed a better binding affinity to WT-MT1-MMP than AF7p as observed through enzyme-linked immunosorbent assay (ELISA) and biolayer interferometry (BLI). The new peptide labeled and attached MT1-MMP expression cell lines HT1080 and did not show any toxicity to cells. Furthermore, for in vivo imaging, HT1080 tumor-bearing mice with higher MT1-MMP expression accumulated more Cy5.5-HS7 than mice with MT1-MMP low-expression cell lines A549 at tumor sites, and the half-life of HS7 was longer than that of AF7p, as confirmed by ex vivo imaging of the main organs. These results suggest the feasibility of using the subtraction biopanning strategy to screen the affinity peptide targeting MT-loop regions and HS7 is a superior probe for noninvasively imaging MT1-MMP expression in MT1-MMP-positive tumor models. It provides impetus for further studies to use HS7 in early diagnosis of tumors and in peptide-mediated drugs.

Two new secolignans from the roots of Urtica fissa.

Two new secolignans, 3,4-trans-3-hydroxymethyl-4-[bis(4-hydroxy-3- methoxyphenyl)methyl]butyrolactone (1) and 3,4-trans-3-hydroxymethyl-4- [bis(3,4-dimethoxyphenyl)methyl]butyrolactone (2) have been isolated from the roots of Urtica fissa E.Pritz. Their structures were determined on the basis of spectroscopic methods, especially 1H NMR, 13C NMR, 2D NMR, and HR-ESI-MS. The inhibitory effects on N1 and N2, two subtypes of neuraminidases (NAs), of these two compounds were assayed.

A Purified Aspartic Protease from Akkermansia Muciniphila Plays an Important Role in Degrading Muc2.

Akkermansia muciniphila can produce various mucin-degrading proteins. However, the functional characteristics of these proteins and their role in mucin degradation are unclear. Of the predicted protein-coding genes, Amuc_1434, which encodes for a hypothetical protein, is the focus in this study. A recombinant enzyme Amuc_1434 containing the 6× His-tag produced in Escherichia coli (hereinafter termed Amuc_1434*) was isolated to homogeneity and biochemically characterised. Results showed that the enzyme can hydrolyse hemoglobin with an activity of 17.21 U/µg. The optimal pH and temperature for hemoglobin hydrolysis of Amuc_1434* were found to be around 8.0 and 40 °C, respectively. Amuc_1434* is identified as a member of the aspartic protease family through the action of inhibitor pepstatin A. Amuc_1434* promotes the adhesion of colon cancer cell line LS174T, which can highly express Muc2. Significantly Amuc_1434* can degrade Muc2 of colon cancer cells. Amuc_1434 is mainly located in the colon of BALB/c mice. These results suggest that the presence of Amuc_1434 from Akkermansia muciniphila may be correlated with the restoration of gut barrier function by decreasing mucus layer thickness.

EGF-induced ERK activation promotes CK2-mediated disassociation of alpha-Catenin from beta-Catenin and transactivation of beta-Catenin.

Increased transcriptional activity of beta-catenin resulting from Wnt/Wingless-dependent or -independent signaling has been detected in many types of human cancer, but the underlying mechanism of Wnt-independent regulation remains unclear. We demonstrate here that EGFR activation results in disruption of the complex of beta-catenin and alpha-catenin, thereby abrogating the inhibitory effect of alpha-catenin on beta-catenin transactivation via CK2alpha-dependent phosphorylation of alpha-catenin at S641. ERK2, which is activated by EGFR signaling, directly binds to CK2alpha via the ERK2 docking groove and phosphorylates CK2alpha primarily at T360/S362, subsequently enhancing CK2alpha activity toward alpha-catenin phosphorylation. In addition, levels of alpha-catenin S641 phosphorylation correlate with levels of ERK1/2 activity in human glioblastoma specimens and with grades of glioma malignancy. This EGFR-ERK-CK2-mediated phosphorylation of alpha-catenin promotes beta-catenin transactivation and tumor cell invasion. These findings highlight the importance of the crosstalk between EGFR and Wnt pathways in tumor development.

Interplay of mevalonate and Hippo pathways regulates RHAMM transcription via YAP to modulate breast cancer cell motility.

Expression of receptor for hyaluronan-mediated motility (RHAMM), a breast cancer susceptibility gene, is tightly controlled in normal tissues but elevated in many tumors, contributing to tumorigenesis and metastases. However, how the expression of RHAMM is regulated remains elusive. Statins, inhibitors of mevalonate metabolic pathway widely used for hypercholesterolemia, have been found to also have antitumor effects, but little is known of the specific targets and mechanisms. Moreover, Hippo signaling pathway plays crucial roles in organ size control and cancer development, yet its downstream transcriptional targets remain obscure. Here we show that RHAMM expression is regulated by mevalonate and Hippo pathways converging onto Yes-associated protein (YAP)/TEAD, which binds RHAMM promoter at specific sites and controls its transcription and consequently breast cancer cell migration and invasion (BCCMI); and that simvastatin inhibits BCCMI via targeting YAP-mediated RHAMM transcription. Required for ERK phosphorylation and BCCMI, YAP-activated RHAMM transcription is dependent on mevalonate and sensitive to simvastatin, which modulate RHAMM transcription by modulating YAP phosphorylation and nuclear-cytoplasmic localization. Further, modulation by mevalonate/simvastatin of YAP-activated RHAMM transcription requires geranylgeranylation, Rho GTPase activation, and actin cytoskeleton rearrangement, but is largely independent of MST and LATS kinase activity. These findings from in vitro and in vivo investigations link mevalonate and Hippo pathways with RHAMM as a downstream effector, a YAP-transcription and simvastatin-inhibition target, and a cancer metastasis mediator; uncover a mechanism regulating RHAMM expression and cancer metastases; and reveal a mode whereby simvastatin exerts anticancer effects; providing potential targets for cancer therapeutic agents.

DNA binding ability of histone-like protein HPhA is negatively affected by interaction with Pb2+.

The histone-like protein (HPhA) is highly homologous to the eukaryotic histones and has the ability to bind to the DNA molecules. In this study, we tested divalent metal ions Mg(2+), Ca(2+), Zn(2+), Pb(2+) for their effect on the recombinant HPhA (rHPhA)-DNA binding. We found that only Pb(2+) was able to reduce the formation of rHPhA-DNA complex using gel mobility shift assays. Equilibrium dialysis showed that Pb(2+) bound to rHPhA by a 2:1 ratio. The interaction of Pb(2+) and rHPhA was further studied by spectroscopic method including fluorescence, ultraviolet visible (UV-Vis) absorption, and circular dichroism (CD) spectroscopies. Fluorescent spectroscopy results suggested that Pb(2+) and rHPhA formed a complex that caused internal quenching of the fluorescence of the protein at the ground state, and the quenching is predominately static and mixed with dynamic quenching. UV-Vis absorption spectrum results showed Pb(2+) caused a slightly blue shift of the maximum absorption wavelength of rHPhA which indicated the reduction of the protein's hydrophobicity. The CD spectrum further indicated that a reduction of the α-helix content of rHPhA occurred upon binding to Pb(2+). Synchronous fluorescence spectrometry analysis revealed that Pb(2+) was able to affect the polarity of the amino acids that near the Trp and Tyr residues. These results together showed that Pb(2+) interact with the recombinant rHPhA and this interaction negatively affect the ability of rHPhA to form complex with DNA molecules.

Simultaneous efficient removal of high-strength ammonia nitrogen and chemical oxygen demand from landfill leachate by using an extremely high ammonia nitrogen-resistant strain.

Bioaugmentation is a promising technology for pollutant elimination from stressed environments, and it would provide an efficient way to solve challenges in traditional biotreatment of wastewater with high strength of ammonia nitrogen (NH4(+)-N). A high NH4(+)-N-resistant bacteria strain, identified as Bacillus cereus (Jlu BC), was domesticated and isolated from the bacteria consortium in landfill leachate. Jlu BC could survive in 100 g/L NH4(+)-N environment, which indicated its extremely high NH4(+)-N tolerance than the stains found before. Jlu BC was employed in the bioaugmented system to remove high strength of NH4(+)-N from landfill leachate, and to increase the removal efficiency, response surface methodology (RSM) was used for optimizing bioaugmentation degradation conditions. At the optimum condition (initial pH 7.33, 4.14 days, initial chemical oxygen demand [COD] concentration [18,000 mg/L], 3.5 mL inoculated domesticated bacteria strain, 0.3 mg/mL phosphorus supplement, 30 °C, and 170 rpm), 94.74 ± 3.8% removal rate of NH4(+)-N was obtained, and the experiment data corresponded well with the predicted removal rate of the RSM models (95.50%). Furthermore, COD removal rate of 81.94 ± 1.4% was obtained simultaneously. The results presented are promising, and the screened strain would be of great practical importance in mature landfill leachate and other NH4(+)-N enrichment wastewater pollution control.

Efficient soluble expression of secreted matrix metalloproteinase 26 in Brevibacillus choshinensis.

Matrix metalloproteinase 26 (MMP-26) is a novel member of the matrix metalloproteinase family with minimal domain constitution and unknown physiological function. The three-dimensional (3D) structure of the enzyme also remains to be deciphered. Previous studies show that MMP-26 may be expressed in Escherichia coli (E. coli) as inclusion bodies and re-natured with catalytic activity. However, the low re-naturation rate of this method limits its usage in structural studies. In this paper, we tried to clone, express and purify the pro form and catalytic form of MMP-26 (ProMMP-26 and CatMMP-26) in several widely used expression vectors and express the recombinant MMP-26 proteins in E. coli cells. These constructs resulted in insoluble expressions or soluble expressions of MMP-26 with little catalytic activity. We then used Brevibacillus choshinensis (B. choshinensis) as the host system for the soluble and active expression of MMP-26. The enzyme was secreted in soluble form in the supernatant of cell culture medium and purified via a two-step purification process that included Ni(2+) affinity chromatography followed by gel filtration. The yields of purified ProMMP-26 and CatMMP-26 were 12 and 18mg/L, respectively, with high purity and homogeneity. Both ProMMP-26 and CatMMP-26 showed gelatin zymography activity and the purified CatMMP-26 had high enzymatic activity against DQ-gelatin substrate. The large-scale soluble and active protein production for future structural studies of MMP-26 is thus feasible using the B. choshinensis host system.

Highly selective azadipeptide nitrile inhibitors for cathepsin K: design, synthesis and activity assays.

We have developed a series of azadipeptide nitriles with different P3 groups. A triaryl meta-phenyl derivative, compound 13, was not only a potent inhibitor for cathepsin K (K(i) = 0.0031 nM), but also highly selective over both cathepsins B and S (~1000-fold). A protein-ligand docking study performed on the series provided a possible explanation why compound 13 could be significantly more potent than the others, especially compound 12 in the same series.

Highly selective aza-nitrile inhibitors for cathepsin K, structural optimization and molecular modeling.

As a new type of cathepsin K inhibitor, azadipeptide nitriles have the characteristics of proteolytic stability and excellent inhibitory activity, but they exhibit barely any satisfactory selectivity. Great efforts have focused on improving their selectivity toward cathepsin K. In this sequential study, we report the further structural optimization, synthesis, molecular modeling, and in vitro enzymatic assays of a new series of potent and selective inhibitors of cathepsin K without the P2-P3 amide linker. Significant selective improvements were achieved for cathepsin K over L, S and B, and a triaryl meta-product possessed the favorable balance between potency (Ki = 0.29 nM) and selectivity of cathepsin K over cathepsin L (320-fold), S (1784-fold) and B (8566-fold). We undertook a covalent protein-ligand docking study to explain the improved selectivity of several representative compounds. Such a selectivity improvement would be useful to avoid harmful side effects in practical applications of these compounds.

Amelioration of alcohol-induced acute liver injury in C57BL/6 mice by a mixture of TCM phytochemicals and probiotics with antioxidative and anti-inflammatory effects.

Background: There are many causes of acute liver injury (ALI), such as alcohol, drugs, infection, and toxic materials, which have caused major health problems around the world. Among these causes, alcohol consumption induced liver injury is a common alcoholic liver disease, which can further lead to liver failure even liver cancer. A number of traditional Chinese medicine (TCM) and TCM derived compounds have been used in treating the liver-associated diseases and combination use of probiotics with TCM phytochemicals has attracted interests for enhanced biological effects. Methods: This study investigated the hepatoprotective effect of TCM-probiotics complex (TCMPC) and its underlying mechanism for the treatment of ALI in mice. The TCMPC is composed of TCM phytochemicals puerarin, curcumin, ginsenosides, and 5 lactobacteria strains. We first established a mouse model of alcohol-induced ALI, then the therapeutic effects of TCMPC on alcohol-induced ALI were monitored. A series of measurements have been performed on antioxidation, anti-inflammation, and lipid metabolism regulation. Results: The results showed that TCMPC can reduce the level of liver injury biomarkers and regulate oxidative stress. Histopathological results indicated that TCMPC could ameliorate ALI in mice. In addition, it can also significantly reduce the production of inflammatory cytokines caused by ALI. Conclusion: Our research has proved the therapeutic effect of TCMPC on alcohol-induced ALI. The potential mechanism of hepatoprotective effects of TCMPC may be related to its antioxidative and anti-inflammatory effects. Our research might provide a new way for liver disease treatment.

Ubiquitin-intein and SUMO2-intein fusion systems for enhanced protein production and purification.

Although most commonly used for protein production, expression of soluble and functional recombinant protein in Escherichia coli is still a major challenge. The development and application of fusion tags that can facilitate protein expression and solubility partly solve this problem, however, under most circumstance, the fusion tags have to be removed by proteases in order to use the proteins. Because the tag removal using proteases increases cost and introduces extra purification steps, it remains a significant problem that must be resolved before being widely used in industry production. Ubiquitin and SUMO have been successfully used to enhance protein expression and solubility. In the last decades, intein has also been widely used in protein production for its self-cleavage property, which could help to remove the fusion tag without any protease. Here, we take the advantages of ubiquitin, SUMO2 and intein in protein expression. We constructed tandem ubiquitin-intein and SUMO2-intein fusion tags, and chose human MMP13 (amino acid 104-274) and eGFP as the passenger proteins that fused to the C-terminus of the tags. These constructs were expressed in E. coli and both MMP13 and eGFP expression and solubility were evaluated. Both tags showed the ability to enhance the solubility of MMP13 and eGFP and improve the expression of eGFP, and the SUMO2-intein having a more significant effect. Both ubiquitin-intein-eGFP and SUMO2-intein-eGFP were purified using Ni-NTA column chromatography and self-cleavaged by changing pH. The recombinant un-tagged eGFP were released and eluted with high homogeneity. In summary, ubiquitin-intein and SUMO2-intein are convenient and useful fusion tags that can enhance the expression, solubility and improve the purification process of the model heterologous protein and these tags may have a good prospect in protein production.