Obacunone Attenuates Liver Fibrosis with Enhancing Anti-Oxidant Effects of GPx-4 and Inhibition of EMT.

Obacunone, a limonin triterpenoid extracted from Phellodendronchinense Schneid or Dictamnus dasycarpusb Turcz plant, elicits a variety of pharmacological effects such as anti-inflammatory, anti-neoplastic, anti-oxidation, and anti-lung-fibrosis ones. However, the anti-fibrotic effect of obacunone and the detailed underlying mechanism in liver fibrosis remain unclear. Liver fibrosis is a debilitating disease threatening human health. Transforming growth factor (TGF)-ß/P-Smad is a major pathway of fibrosis featured with epithelia mesenchymal transformations (EMT) and collagen depositions, accompanying with excessive oxygen-free radicals. Nrf-2 acts as a key anti-oxidative regulator driving the expressions of various antioxidant-related genes. Glutathionperoxidase-4 (GPx-4) is a member of the glutathione peroxidase family that directly inhibits phospholipid oxidation to alleviate oxidative stress. In the present study, we aimed to explore the role of obacunone in mouse liver fibrosis model induced by carbon tetrachloride (CCl4) and in hepatic stellate cells (LX2 cell line) challenging with TGF-ß. Obacunone demonstrated potent ameliorative effects on liver fibrosis both in activated LX2 and in mice liver tissues with reduced levels of α-SMA, collagen1, and vimentin. Obacunone also remarkably suppressed the TGF-ß/P-Smad signals and EMT process. Meanwhile, obacunone exerted a potent anti-oxidation effect by reducing the levels of reactive oxygen species (ROS) in both models. The antioxidant effect of obacunone was attributed to the activation of GPx-4 and Nrf-2. In addition, the therapeutic effect of obacunone on LX2 cells was significantly removed in vitro plus with GPx-4 antagonist RSL3, in parallel with the re-elevated levels of ROS. Thus, we demonstrate that obacunone is able to attenuate liver fibrosis via enhancing GPx-4 signal and inhibition of the TGF-ß/P-Smad pathway and EMT process.

PAMP protects intestine from Enterohemorrhagic Escherichia coli infection through destroying cell membrane and inhibiting inflammatory response.

Proadrenomedullin N-terminal 20 peptide (PAMP) is elevated in sepsis, but the function and possible mechanism of PAMP in bacterial infection is elusive. This study is aim to evaluate the role of PAMP in the interaction between the Enterohemorrhagic E. coli (EHEC) and the host barrier. Our results showed that PAMP alleviated the EHEC-induced disruption of goblet cells and mucosal damage in the intestine, increased the expression of occludin in the colon of EHEC-infected mice, and reduced the proinflammatory cytokines level in serum significantly compared with the control group. Meanwhile, lipopolysaccharide (LPS) stimulation could dose-dependently induce the expression of preproADM, the precursor of PAMP, in human intestinal epithelial cell (HIEC) and human umbilical vein endothelial cell (HUVEC). In addition, PAMP inhibited the growth of EHEC O157:H7 and destroyed the inner and outer membrane. At low concentration, PAMP attenuated the EHEC virulence genes including hlyA and eaeA, which was also confirmed from reduced hemolysis to red cells and adhesion to HIEC. These results indicated that EHEC infection would modulate the expression of PAMP in intestinal epithelium or vascular endothelium, and in turn exerted a protective effect in EHEC induced infection by rupturing the bacterial cell membrane and attenuating the bacterial virulence.

Earlier changes in mice after D-galactose treatment were improved by mitochondria derived small peptide MOTS-c.

MOTS-c, as a mitochondria derived peptide, exerts benefits for insulin resistance in HFD mice and against various stresses in an AMPK dependent way. Here, in the D-galactose chronic injection models, exogenous MOTS-c was given to determine its direct anti-aging effects. The body weight, insulin sensitivity and blood glucose were determined with mild differences. Tissue morphology analyses disclosed that liver, visceral fat and dermal skin, all displayed aberrant lipid depositions in the D-galactose mice. MOTS-c treatment largely alleviated the lipid accumulations, corresponding with positive changes in mitochondria dynamics, observed in liver transmission electron microscopy and in altered mRNA levels of Drp1 and mitofusins. Notably, the aging phenotypes of small intestine tract were more obvious, including histological defects and lower Ki67 levels, plus with the higher levels of DNA stress, such as P21 and P16, as well as mitochondria dynamics. Collectively, these data provided the direct evidence to support that exogenous givings of MOTS-c prevented abnormal fat accumulations in D-gal mice, putatively via improvement of mitochondria dynamic related pathways.

MOTS-c inhibits Osteolysis in the Mouse Calvaria by affecting osteocyte-osteoclast crosstalk and inhibiting inflammation.

The Mitochondrial-derived peptide MOTS-c has recently been reported as a 16-amino acid peptide regulating metabolism and homeostasis in different cells. However, its effects on immune cells and bone metabolism are rarely reported. Here we demonstrate that MOTS-c treatment in ultra-high molecular weight polyethylene (UHMWPE) particle-induced osteolysis mouse model alleviated bone erosion and inflammation. MOTS-c increased osteoprotegerin (OPG)/ receptor activator of nuclear factor kappa-B ligand (RANKL) ratio in osteocytes, leading to inhibition of osteoclastogenesis. In primary bone marrow macrophages (BMMs) MOTS-c alleviated STAT1 and NF-κB phosphorylation triggered by UHMWPE particles. Promoting ROS production or suppressing peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) by adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) repression blocked these anti-inflammatory effects of MOTS-c treatment. Taken together, these findings provide evidence that the small peptide inhibits osteoclastogenesis by regulating osteocyte OPG/RANKL secretion and suppressing inflammation via restraining NF-κB and STAT1 pathway. Moreover, its effects on NF-κB activation is dependent on the AMPK-PGC-1α-ROS axis, suggesting its potential use in osteolysis and other inflammation disorders.

Metformin protects bone mass in ultra-high-molecular-weight polyethylene particle-induced osteolysis by regulating osteocyte secretion.

Metformin, an anti-hyperglycemic agent used for type 2 diabetes, has recently been found to have more effects apart from glucose regulation. We found that, in ultra-high-molecular-weight polyethylene particle-induced osteolysis mouse models, metformin had bone protect property and reduced the negative regulator of bone formation sclerostin (SOST) and Dickkopf-related protein 1 (DKK1), and increased osteoprotegerin (OPG) secretion and the ratio of OPG/Receptor Activator for Nuclear Factor-κB Ligand (RANKL). In vitro, we established a 3D co-culture system in which metformin affects osteoblasts and osteoclasts through mature osteocytes secretion. Metformin (50 µM) significantly decreased SOST and DKK1 mRNA expression, stimulating alkaline phosphatase activity and proliferation of osteoblast, and increased OPG secretion and the ratio of OPG/RANKL, inhibiting osteoclastogenesis. Moreover, the effect on OPG was reversed by adenosine 5'-monophosphate-activated protein kinase inhibitor, Compound C. Our finding suggests that metformin induces differentiation and mineralization of osteoblasts, while inhibits osteoclastogenesis via mature osteocytes secretion. Therefore, the drug might be beneficial for not only diabetes but also in other bone disorders by acting on mature osteocytes.

RNA-binding protein QKI regulates contact inhibition via Yes-associate protein in ccRCC.

Contact inhibition adjusts organ size to the proper size and ensures the cultured cells growing to a monolayer. By regulating the downstream coordinator YAP, the evolutionarily conserved Hippo transduction pathway attunes cell growth and death in response to cell contact inhibition, polarity, self-renewal, and differentiation. Dysregulation of this pathway is involved in various diseases such as cancer. RNA-binding protein QKI regulates cell proliferation, metabolism, division, and immunity in various cancer models, but its role in cancer cell contact inhibition remains unclear. In this study, we aimed to clarify the relationship between QKI and YAP, and the role of their interaction in cell contact inhibition. We found a lower QKI expression level in sparse condition, whereas a higher expression level in confluent condition by western blot analysis and immunofluorescence assay. QKI knockdown elevated cell proliferation and invasion both in vitro and in vivo. Strikingly, the results of CCK-8 assay, colony formation assay, and transwell assay showed that the phenomenon was in accord with the expression level of pYAP and reverse with YAP. Higher levels of Wnt3a and ß-catenin were also found in xenografts of QKI-knockdown clear cell renal cell carcinoma (ccRCC) CAKI-1 cells by western blot analysis and immumohistochemical staining. Finally, a positive correlation between QKI and pYAP was found in clinical specimens by immunohistochemistry. Thus, as a negative regulator of YAP, QKI attuned the cell contact inhibition, leading to inhibition of cancer cell proliferation and invasion through Wnt and GPCR pathway.

Light curve measurements with a superconducting nanowire single-photon detector.

The superconducting nanowire single-photon detector (SNSPD) is used to detect the sunlight reflected by the artificial satellite and space debris. In the process, light curves of the satellite and space debris are successfully measured. In 2017, a space-debris laser ranging system with a four-element SNSPD is developed by Yunnan Observatories in China. During the ranging experiments, the detector works in a freely detecting state. It can detect photons not only of the laser echo, but also of the sunlight reflected by the target. After separating the data triggered by background light from the whole detected data set, the light curves of satellites, including Topex and several types of debris, are acquired. The apparent rotation rate of the satellite Topex is determined by analyzing the light curves by Fourier transform and phase dispersion minimization. On the basis of a laser ranging system using SNSPDs, the simultaneous measurement of the laser ranging and light curves of some space targets without any additional equipment is realized for the first time, to the best of our knowledge.

Antibiotics-induced gut microbiota dysbiosis promotes tumor initiation via affecting APC-Th1 development in mice.

Gut microbiota is critical for maintaining body immune homeostasis and thus affects tumor growth and therapeutic efficiency. Here, we investigated the link between microbiota and tumorgenesis in a mice model of subcutaneous melanoma cell transplantation, and explored the underlying mechanism. We found disruption of gut microbiota by pretreating mice with antibiotics promote tumor growth and remodeling the immune compartment within the primary tumor. Indeed, gut microbial dysbiosis reduced the infiltrated mature antigen-presenting cells of tumor, together with lower levels of co-stimulators, such as CD80, CD86 and MHCII, as well as defective Th1 cytokines, including IFNγ, TNFα, IL12p40, and IL12p35. Meantime, splenic APCs displayed blunted ability in triggering T cell proliferation and IFNγ secretion. However, oral administration of LPS restored the immune surveillance effects and thus inhibited tumor growth in the antibiotics induced gut microbiota dysbiosis group. Taken together, these data highly supported that antibiotics induced gut microbiota dysbiosis promotes tumor initiation, while LPS supplementation would restore the effective immune surveillance and repress tumor initiation.

Satellite laser ranging using superconducting nanowire single-photon detectors at 1064 nm wavelength.

Satellite laser ranging operating at 1064 nm wavelength using superconducting nanowire single-photon detectors (SNSPDs) is successfully demonstrated. A SNSPD with an intrinsic quantum efficiency of 80% and a dark count rate of 100 cps at 1064 nm wavelength is developed and introduced to Yunnan Observatory in China. With improved closed-loop telescope systems (field of view of about 26''), satellites including Cryosat, Ajisai, and Glonass with ranges of 1600 km, 3100 km, and 19,500 km, respectively, are experimentally ranged with mean echo rates of 1200/min, 4200/min, and 320/min, respectively. To the best of our knowledge, this is the first demonstration of laser ranging for satellites using SNSPDs at 1064 nm wavelength. Theoretical analysis of the detection efficiency and the mean echo rate for typical satellites indicate that it is possible for a SNSPD to range satellites from low Earth orbit to geostationary Earth orbit.

TOM40 mediates the effect of TSPO on postpartum depression partially through regulating calcium homeostasis in microglia.

AIMS: To assess the effect of the translocator protein 18 kDa (TSPO) on postpartum depression and explore its mechanism. METHODS: Postpartum depression (PPD) mouse model was established, and flow cytometry, immunofluorescence, Western blot analysis, real-time quantitative PCR, adeno-associated virus (AAV), co-immunoprecipitation-mass spectrometry and immunofluorescence co-staining were used to detect the effect of TSPO ligand ZBD-2 on PPD mice. RESULTS: ZBD-2 inhibits the overactivation of microglia in the hippocampus and amygdala of PPD model mice. ZBD-2 not only inhibited the inflammation but also repressed the burst of reactive oxygen species (ROS) and mitochondrial ROS (mtROS). Meanwhile, ZBD-2 protects mitochondria from LPS-induced damages through inhibiting the influx of calcium. ZBD-2 modulated the calcium influx by increasing the level of translocase of the outer mitochondrial membrane 40 (TOM40) and reducing the interaction of TSPO and TOM40. In addition, the effect of ZBD-2 was partially dependent on anti-oxidative process. Knockdown of TOM40 by adeno-associated virus (AAV) in the hippocampus or amygdala dramatically reduced the effect of ZBD-2 on PPD, indicating that TOM40 mediates the effect of ZBD-2 on PPD. CONCLUSIONS: TOM40 is required for the effect of ZBD-2 on treating anxiety and depression in PPD mice. This study reveals the role of microglia TSPO in PPD development and provides the new therapeutic strategy for PPD.

[The emerging roles of the RNA binding protein quaking in regulating differentiation and function of monocytes-macrophages].

Macrophages are a class of innate immune cells with strong plasticity. They can polarize into different phenotypes, serving with various functions, such as phagocytosis and chemotaxis, which is involved in the development of diseases. RNA-binding protein quaking (QKI) regulates monocyte differentiation, macrophage polarization and various cellular functions through RNA splicing, translocation and expression. QKI regulates the differentiation of monocytes into macrophages, and QKI deficiency promotes the polarization of macrophages into M1 type, which exerts a pro-inflammatory phenotype. In contrast, QKI overexpression promotes macrophage polarization into M2 type. Additionally, QKI affects macrophage phagocytic receptor and chemokine expression. Due to the variations in tissue-resident macrophages' features, QKI modulates macrophages in the pathogenesis of diseases (atherosclerosis, inflammatory bowel disease, etc.) through diverse mechanisms, which mainly involves cyclicAMP response element binding protein (CREB) transcription factor regulation, signal transducer and activator of transcription 1/nuclear factor κB (STAT1/NF-κB) inflammatory signaling pathway and pre-mRNA splicing of phagocytic receptor.

RNA-binding Protein QKI Inhibits Osteogenic Differentiation Via Suppressing Wnt Pathway.

BACKGROUND: Dysregulation of MSCs differentiation is associated with many pathophysiological processes. Genetically modified MSCs transplantation helps restore bone loss efficiently. METHODS: BMSCs-specific QKI overexpressing and knockdown mice were built to explore QKI's role in bone formation and fat accumulation. Primary BMSCs with QKI overexpression and knockout were subjected to osteogenic and adipogenic differentiation. ALP staining and oil red O staining were performed to evaluate the differences between the groups. RNA immunoprecipitation was performed to identify the QKI-related pathway. QKI deficient BMSCs were transplanted into mice with glucocorticoid-induced osteoporosis to evaluate its therapeutic potential. RESULTS: Mice harboring BMSC-specific transgenic QKI exhibited reduced bone mass, while BMSC-specific QKI-deficient mice showed an increase in bone mass. Osteogenic differentiation of QKI deficient BMSCs was promoted and adipogenic differentiation was inhibited, while QKI overexpression in BMSCs displayed the opposite effects. To define the underlying mechanisms, RIP sequencing was performed. Wnt pathway-related genes were the putative direct target mRNAs of QKI, Canonical Wnt pathway activation was involved in QKI's effects on osteogenic differentiation. RNA immunoprecipitation quantitative real-time Polymerase Chain Reaction (PCR) and RNA fluorescence in situ hybridization experiments further validated that QKI repressed the expressions of Wnt5b, Fzd7, Dvl3 and ß-catenin via direct binding to their putative mRNA specific sites. Glucocorticoid-induced osteoporotic mice transplanted with QKI deficient BMSCs exhibited less bone loss compared with mice transplanted with control BMSCs. CONCLUSIONS: QKI suppressed BMSCs osteogenic differentiation by downregulating the expressions of Wnt5b, Fzd7, Dvl3 and ß-catenin. Loss of QKI in BMSCs transplantation may provide a new strategy for the treatment of orthopedic diseases such as osteoporosis.

QKI deficiency in macrophages protects mice against JEV infection by regulating cell migration and antiviral response.

Japanese encephalitis (JE) is a major reason to cause viral encephalitis, with 50% patients suffering from severe neuro-inflammation and permanent neural injury. Effective anti-viral treatment is urgently needed. Here, we found RNA binding protein quaking (QKI) was involved in the progression of JE by regulating migration and anti-viral response of macrophages. After JE virus (JEV) infection, QKI-deficient mice had lower viral loads in the brain and fewer neurological symptoms. In comparison with control mice, proinflammatory cytokines in the brain of QKI-deficient animals revealed distinct patterns, with lower levels of IL-6 (interleukin-6) and IFN-ß (interferon-ß) at the early stage but higher levels at the end of JE. Then we found infiltration of CCR2 positive ((C-C motif) receptor 2) peripheral macrophages and CCR2 expression on macrophages were inhibited in QKI-deficient mice, while the expression of CCR2 ligands was not changed. Bioinformatical analysis showed that a QRE (quaking response element) located on 3'UTR (untranslated region) of Ccr2. We further verified that QKI was able to interact with Ccr2 mRNA and regulate its degradation in vitro. Additionally, since the IFN-ß production was increased in QKI-ablation mice after JEV infection, the anti-viral response was analyzed. Results in QKI-silenced N9 cells showed that the expression of RIG-I (retinoic acid-inducible gene-I) and TBK1 (TANK binding kinase 1) was increased, thus further inducing IRF3 (interferon regulatory factor 3) phosphorylation and interferon activation. Overall, these results revealed QKI mediated the anti-viral process via interfering migration of macrophages to CNS (central nervous system) and enhancing RIG-I/IRF3/IFN-ß pathway to restrict virus dissemination.

Rapid and Sensitive Assay of Helicobacter pylori With One-Tube RPA-CRISPR/Cas12 by Portable Array Detector for Visible Analysis of Thermostatic Nucleic Acid Amplification.

Helicobacter pylori (H. pylori) has infected more than half of the world's population and is still a threat to human health. The urea breath test, despite being widely used in clinical diagnosis, still faces huge challenges in the immediate detection of H. pylori. Thus, a rapid, sensitive, and highly specific point of care diagnosis is particularly important for preventing the further transmission of H. pylori and for real-time monitoring of the disease in a given population. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostics have been applied to various types of nucleic acid testing; however, there are often shortcomings of complex operation and high signal transmission background. In this study, we proposed a new platform for the assay of H. pylori using one-tube-based CRISPR/Cas12a diagnostic methods and designed a detector for this platform, which is a portable array detector for visible analysis of thermostatic nucleic acid amplification (Pad-VATA). By incorporating isothermal recombinase polymerase amplification, our platform could detect the conserved gene fragments of H. pylori with a constant low as 2 copies/µl. The assay process can be performed at a single temperature in about 30 min and integrated into the reactor in the palm-sized Pad-VATA to facilitate rapid diagnosis of H. pylori. We also verified the accuracy of our platform using 10 clinical samples and found that the platform can quickly detect H. pylori infection in a given population. We believe that this fast, convenient, efficient, and inexpensive screening and diagnostic platform can be widely used in various settings, including homes and clinics.

In vitro Anti-Hantavirus Activity of Protein Kinase Inhibitor 8G1 Targeting AKT/mTOR/eIF4E Signaling Pathway.

Hantaan virus (HTNV) is the main cause of hemorrhagic fever with renal syndrome (HFRS) around the world, which results in profound morbidity and mortality. However, there are currently no FDA-approved therapeutics or vaccines against HFRS. To find new anti-HTNV drugs, the inhibitory activity of 901 small molecule kinase inhibitors against HTNV is analyzed. Among these compounds, compound 8G1 inhibits HTNV with a relatively high inhibition rate and lower toxicity. The viral titer and nucleocapsid protein of HTNV are reduced after compound 8G1 treatment in a dose-dependent manner at concentrations ranging from 1 to 20 µM. In addition, the administration of compound 8G1 at the early stage of HTNV infection can inhibit the replication of HTNV. The molecular docking result reveals that compound 8G1 forms interactions with the key amino acid residues of serine/threonine-protein kinase B (Akt), which is responsible for the observed affinity. Then, the mammalian target of rapamycin (mTOR) and eukaryotic translation initiation factor 4E (eIF4E) signaling pathways are inhibited. Our results may help to design novel targets for therapeutic intervention against HTNV infection and to understand the anti-HTNV mechanism of protein kinase inhibitors.

QKI degradation in macrophage by RNF6 protects mice from MRSA infection via enhancing PI3K p110ß dependent autophagy.

BACKGROUND: Sepsis is a fatal condition commonly caused by Methicillin-resistant Staphylococcus aureus (MRSA) with a high death rate. Macrophages can protect the host from various microbial pathogens by recognizing and eliminating them. Earlier we found that Quaking (QKI), an RNA binding protein (RBP), was involved in differentiation and polarization of macrophages. However, the role of QKI in sepsis caused by pathogenic microbes, specifically MRSA, is unclear. This study aimed to investigate the role of QKI in regulation of host-pathogen interaction in MRSA-induced sepsis and explored the underlying mechanisms. METHODS: Transmission electron microscope and immunofluorescence were used to observe the autophagy level in macrophages. Real-time PCR and western blot were used to analyzed the expression of mRNA and protein respectively. The potential protein interaction was analyzed by iTRAQ mass spectrometry and Immunoprecipitation. RNA fluorescence in situ hybridization, dual-luciferase reporter assay and RNA immunoprecipitation were used to explore the mechanism of QKI regulating mRNA of PI3K-p110ß. RESULTS: The mRNA level of QKI was aberrantly decreased in monocytes and PBMCs of septic patients with the increasing level of plasma procalcitonin (PCT). Then the mice with myeloid specific knockout of QKI was challenged with MRSA or Cecal Ligation and Puncture (CLP). Mice in these two models displayed higher survival rates and lower bacterial loads. Mechanistically, QKI deletion promoted phagocytosis and autophagic degradation of MRSA via activating p110ß (a member of Class IA phosphoinositide 3-kinases) mediated autophagic response. QKI expression in macrophages led to the sequestration of p110ß in mRNA processing (P) bodies and translational repression. Upon infection, the direct interaction of RNF6, a RING-type E3 ligase, mediated QKI ubiquitination degradation and facilitated PI3K-p110ß related autophagic removal of pathogen. The administration of nanoparticles with QKI specific siRNA significantly protected mice from MRSA infection. CONCLUSIONS: This study disclosed the novel function of QKI in the P body mRNA regulation during infection. QKI degradation in macrophage by RNF6 protects mice from MRSA infection via enhancing PI3K-p110ß dependent autophagy. It suggested that QKI may serve as a potential theranostic marker in MRSA-induced sepsis.

Loss of QKI in macrophage aggravates inflammatory bowel disease through amplified ROS signaling and microbiota disproportion.

Inflammatory bowel disease (IBD) is a refractory chronic inflammatory illness of the gastrointestinal (GI) tract. Macrophage exerts an important role in IBD development. QKI, as an RNA binding protein, was related with inflammatory responses in bacterial infections by regulating the polarization of macrophages. Therefore, we suspected that QKI-regulated macrophages have the potential to play a certain role in IBD and the underlying mechanism. Our results demonstrated that the mice with macrophage-specific deletion of QKI induced with dextran sodium sulfate (DSS) are more susceptible to IBD development, exhibited a severe leaky gut barrier phenotype and higher intense oxidative stress, which are rescued by treating with butylated hydroxyanisole (BHA), an agonist of NRF2. Mechanically, we observed that Keap1 mRNA in the nucleus was exported to the cytoplasm after LPS stimuli in parallel with QKI reductions, and the removal of QKI by shRNA facilitated Keap1 mRNA nuclear exporting and expression in cytoplasm, consequently NRF2 activation in nucleus was weakened, and led to the impaired antioxidant abilities. In addition, mice models of fecal microbiota transplant (FMT) and the co-culturing of mice epithelia cells with feces derived from the DSS-treated QKI-deficit mice revealed consistently aggravated colitis along with a severe oxidative stress; 16S sequencing analysis substantiated the altered compositions of commensal bacteria too. Overall, the current study represents the first effort to explore the anti-oxidant role of QKI in the intestinal macrophage via post-transcriptional regulation of Keap1 mRNA localization and the relevant NRF2 antioxidant signaling, and the disproportional changes in the microbiota were attributable to the mediation of pathogenic damage in the IBD development of QKI-deficit mice.

Impairment of the Cell Wall Ligase, LytR-CpsA-Psr Protein (LcpC), in Methicillin Resistant Staphylococcus aureus Reduces Its Resistance to Antibiotics and Infection in a Mouse Model of Sepsis.

Staphylococcus aureus is a major opportunistic pathogen, infecting animals, and human beings. The bacterial cell wall plays a crucial role in antimicrobial resistance and its infection to host cells. Peptidoglycans (PGs) are a major component of the cell wall in S. aureus, which is heavily decorated with wall teichoic acids (WTAs) and capsular polysaccharides (CPs). The ligation of WTAs and CPs to PGs is catalyzed by LytR-CpsA-Psr (LCP) family proteins, including LcpA, LcpB, and LcpC. However, the involvement of LcpC in antimicrobial resistance of S. aureus and its infection to host cells remains unknown. By creating the LcpC-knockout strains, we showed that the deficiency in LcpC decreased the antimicrobial resistance to ß-lactams and glycopeptides and impeded the binding to various epithelial cells. These changes were accompanied by the morphological changes in bacterial cell wall. More importantly, the knockout of LcpC significantly reduced the pathogenicity of methicillin-resistant S. aureus (MRSA) in mice. Our results suggest that LcpC might be an appealing target for developing a therapeutic approach against MRSA infections.

Synergistic Effects of Two-Dimensional MXene and Ammonium Polyphosphate on Enhancing the Fire Safety of Polyvinyl Alcohol Composite Aerogels.

Fire and smoke suppressions of polyvinyl alcohol (PVA) aerogels are urgently required due to the serious fire hazard they present. MXene, a 2D transition-metal carbide with many excellent properties, is considered a promising synergist for providing excellent flame retardant performance. PVA/ammonium polyphosphate (APP)/transition metal carbide (MXene) composite aerogels were prepared via the freeze-drying method to enhance the flame retardancy. Thermogravimetric analysis, limiting oxygen index, vertical burning, and cone calorimeter tests were executed to investigate the thermal stability and flame retardancy of PVA/APP/MXene (PAM) composite aerogels. The results demonstrated that MXene boosted the flame retardancy of PVA-APP, and that PAM-2 (with 2.0 wt% MXene loading) passed the V-0 rating, and reached a maximum LOI value of 42%; Moreover, MXene endowed the PVA-APP system with excellent fire and smoke suppression performance, as the the peak heat release rate and peak smoke production rate were significantly reduced by 55% and 74% at 1.0 wt% MXene loading. The flame retardant mechanism was systematically studied, MXene facilitated the generation of compact intumescent residues via ita catalyst effects, thus further restraining the release of heat and smoke. This work provides a simple route to improve the flame retardancy of PVA aerogels via the synergistic effect of MXene and APP.

Nobiletin Inhibits Cell Viability via the SRC/AKT/STAT3/YY1AP1 Pathway in Human Renal Carcinoma Cells.

Nobiletin is a polymethoxy flavonoid isolated from Citrus depressa and Citrus reticulata. It has been reported that nobiletin can suppress tumors. We primarily explored the antitumor effects of nobiletin and the associated potential mechanisms in ACHN and Caki-2 renal carcinoma cells. A CCK-8 assay and cloning experiments were used to assess cell viability, and a transwell assay and scratch test were used to assess metastatic ability. The cell cycle was analyzed by flow cytometry, whereas apoptosis was analyzed using flow cytometry and a terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay. Protein expression was examined by Western blot and immunofluorescence. Renal cancer cells were subcutaneously transplanted into nude mice for in vivo studies. The data showed that nobiletin administration significantly dose- and time-dependently suppressed renal cancer cell proliferation; moreover, nobiletin treatment induced cell cycle arrest in the G0/G1 phase and promoted apoptosis. Immunofluorescence analysis indicated that nobiletin decreased the nuclear localization of signal transducer and activator of transcription 3 (STAT3) and YY1-associated protein 1 (YY1AP1). Western blot showed that the levels of phosphorylated SRC, phosphorylated AKT serine/threonine kinase (AKT), and phosphorylated STAT3 were decreased, whereas that of phosphorylated YY1AP1 was increased. The results further showed that application of insulin-like growth factor 1 (IGF1) was able to reverse the nobiletin-induced changes in the levels of phosphorylated AKT, phosphorylated STAT3, and phosphorylated YY1AP1, and could also reverse the antitumor effects of nobiletin. The results of in vivo experiments showed that, compared to the control, tumor volume and weight were both reduced following nobiletin treatment. In conclusion, our study demonstrated that nobiletin can inhibit renal carcinoma cell viability and provides a novel therapeutic approach for the treatment of kidney cancer.