Kinetics Conditioning of (Electro) Chemically Stable Zn Anode with pH Regulation Toward Long-Life Zn-Storage Devices.

The safety, low cost, and high power density of aqueous Zn-based devices (AZDs) appeal to large-scale energy storage. Yet, the presence of hydrogen evolution reaction (HER) and chemical corrosion in the AZDs leads to local OH- concentration increasement and the formation of ZnxSOy(OH)z•nH2O (ZHS) by-products at the Zn/electrolyte interface, causing instability and irreversibility of the Zn-anodes. Here, a strategy is proposed to regulate OH- by introducing a bio-sourced/renewable polypeptide (ɛ-PL) as a pH regulator in electrolyte. The consumption of OH- species is evaluated through in vitro titration and cell in vivo in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy at a macroscopic and molecular level. The introduction of ɛ-PL is found to significantly suppress the formation of ZHS and associated side reactions, and reduce the local coordinated H2O of the Zn2+ solvation shell, widening electrochemical stable window and suppressing OH- generation during HER. As a result, the inclusion of ɛ-PL improves the cycle time of Zn/Zn symmetrical cells from 15 to 225 h and enhances the cycle time of aqueous Zn- I2 cells to 1650 h compared to those with pristine electrolytes. This work highlights the potential of kinetical OH- regulation for by-product and dendrite-free AZDs.

Anomalous Inferior Zn Anode in High-Concentration Electrolyte: Leveraging Solid-Electrolyte-Interface for Stabilized Cycling of Aqueous Zn-Metal Batteries.

Aqueous Zn-metal batteries (AZMBs) are promising large-scale energy storage devices for their high safety and theoretical capacity. However, unstable Zn-electrolyte interface and severe side reactions have excluded AZMBs from long cycling required by practically reversible energy storage. Traditional high-concentration electrolyte is an effective strategy to suppress dendrites growth and resolve the poor electrochemical stability and reversibility of Zn-metal anodes, yet how scientifically universal such strategy is for hybrid electrolyte of different concentrations remains unclear. Herein, we studied the electrochemical behaviors of AZMBs comprising a ZnCl2 -based DMSO/H2 O electrolyte of two distinct concentrations (1 m vs. 7 m). The electrochemical stability/reversibility of Zn anodes in both symmetric and asymmetric cells with high-concentration electrolytes are unusually inferior to the ones with low-concentration electrolyte. It was found that more DMSO components in the solvation sheath of low-concentration electrolyte exist at the Zn-electrolyte interface than in high-concentration counterpart, enabling higher organic compositions in solid-electrolyte-interface (SEI). The rigid inorganic and flexible organic compositions of SEI decomposed from the low-concentration electrolyte is accounted for improved cycling and reversibility of Zn metal anodes and the respective batteries. This work reveals the critical role of SEI than the high concentration itself in delivering stable electrochemical cycling in AZMBs.

Study of torsional strain effect on dynamic behavior of carbon nanotube thermal actuator.

In this paper, a regulation method through torsional strain effect is proposed for carbon nanotube linear thermal actuators. The effects of torsional strain effect on the linear driven performance of linear actuators are systematically studied by molecular dynamics method, and the effect mechanism is revealed as well. It was found that the torsional strain affects the thermal driving force and the friction effect by changing the spacing between the carbon tubes and lattice vibration modes, then further affects the linear driving characteristics. The influence mechanism of torsional strain on the driving characteristics is analyzed and the valuable conclusions for nanoscale strain engineering application are obtained. The work of this paper provides a new idea for performance regulation for nano-driving by using strain effect, and has important guiding significance for nanoscale strain engineering.

New Seco-DSP derivatives as potent chemosensitizers.

Thirty-four seco-3'R,4'R-disubstituted-2',2'-dimethyldihydropyrano[2,3-f]chromone (seco-DSP) derivatives were designed, synthesized and evaluated for chemo-reversal activity when combined with paclitaxel or vincristine in P-gp overexpressing A2780/T and KB-VIN drug-resistant cancer cell lines. Most of the compounds displayed moderate to significant MDR reversal activities. Compound 7e showed the most potent chemo-sensitization activity with more than 1471 reversal ratio at a concentration of 10 µM, which was higher than verapamil (VRP) (212-fold). Unexpectedly the newly synthesized compounds did not show chemosensitization activities in a non-P-gp overexpressing cisplatin resistant human ovarian cancer cell line (A2780/CDDP), implying that the MDR reversal effects might be associated with P-gp overexpression. Moreover, the compounds did not exhibit significant anti-proliferative activities against non-tumorigenic cell lines (HUVEC, HOSEC and T29) compared to VRP at the tested concentration and might be safer than VRP. In preliminary pharmacological mechanism studies, the compounds increased accumulation of DOX and promoted P-gp ATPase activity in A2780/T cell lines. Western blot analysis indicated they did not affect the expression level of P-gp in the tested MDR cell lines. Thus, further studies on these seco-DSP derivatives are merited with the goal of developing a desirable chemosensitizer drug candidate.

Seco-4-methyl-DCK derivatives as potent chemosensitizers.

Twenty-five seco-4-methyl-DCK derivatives were designed, synthesized and evaluated for chemoreversal activity when combined with paclitaxel or vincristine in two drug-resistant cancer cell lines (A2780/T and KB-V) respectively. Most of the new compounds displayed moderate to significant MDR reversal activities in the P-gp overexpressing A2780/T and KB-V cells. Especially, compounds 7o and 7y showed the most potent chemosensitization activities with more than 496 and 735 reversal ratios at a concentration of 10 µM. Unexpectedly the newly synthesized compounds did not show chemosensitization activities observed in a non-P-gp overexpressing cisplatin resistant human ovarian cancer cell line (A2780/CDDP), implying that the MDR reversal effects might be associated with P-gp overexpression. Moreover, these compounds did not exhibit significant antiproliferative activities against nontumorigenic cell lines (HUVEC, HOSEC and T29) compared to the positive control verapamil at the tested concentration, which suggested better safety than verapamil. The pharmacological actions of the compounds will be studied further to explore their merit for development as novel candidates to overcome P-gp mediated MDR cancer.

A family 30 glucurono-xylanase from Bacillus subtilis LC9: Expression, characterization and its application in Chinese bread making.

A GH30-8 endoxylanase was identified from an environmental Bacillus subtilis isolate following growth selection on aspen wood glucuronoxylan. The putative endoxylanase was cloned for protein expression and characterization in the Gram-positive protease deficient protein expression host B. subtilis WB800. The extracellular activity obtained was 55 U/mL, which was 14.5-fold higher than that obtained with the native species. The apparent molecular mass of BsXyn30 was estimated as 43 kDa by SDS-PAGE. BsXyn30 showed an optimal activity at pH 7.0 and 60 °C. Recombinant BsXyn30 displayed maximum activity against aspen wood xylan, followed by beechwood xylan but showed no catalytic activity on arabinose-substituted xylans. Analysis of hydrolyzed products of beechwood xylan by thin-layer chromatography and mass spectroscopy revealed the presence of xylooligosaccharides with a single methyl-glucuronic acid residue. BsXyn30 exhibited very low activity for hydrolysis xylotetraose and xylopentaose, but had no detectable activity against xylobiose and xylotriose. Using BsXyn30 as an additive in breadmaking, a decrease in water-holding capacity, an increase in dough expansion as well as improvements in volume and specific volume of the bread were recorded. Thus, the present study provided the basis for the application of GH30 xylanase in breadmaking.

Novel Nitric Oxide Donors of Phenylsulfonylfuroxan and 3-Benzyl Coumarin Derivatives as Potent Antitumor Agents.

In this work, five new hybrids of phenylsulfonylfuroxan merging 3-benzyl coumarin and their seco-B-ring derivatives 2-6 were designed and synthesized. Among them, compound 3 showed the most potent antiproliferation activities with IC50 values range from 0.5 to 143 nM against nine drug-sensitive and four drug-resistant cancer cell lines. Preliminary pharmacologic studies showed that these compounds displayed lower toxicities than that of lead compound 1. Compound 3 obviously induced the early apoptosis and hardly affected the cell cycle of A2780, which was significantly different from compound 1. Especially, it gave 559- and 294-fold selectivity antiproliferation activity in P-gp overexpressed drug-resistant cancer cell lines MCF-7/ADR and KB-V compared to their drug-sensitive ones MCF-7 and KB, implying that compounds 2-6 might have an extra mechanism of anti-MDR-cancer with P-gp overexpression.

A hybrid of coumarin and phenylsulfonylfuroxan induces caspase-dependent apoptosis and cytoprotective autophagy in lung adenocarcinoma cells.

BACKGROUND: Lung adenocarcinoma is the most primary histologic subtype of non-small cell lung cancer (NSCLC). Compound 8b, a novel coumarin derivative with phenylsulfonylfuroxan group, shows significant antiproliferation activity against lung adenocarcinoma cell with low toxicity. PURPOSE: This study aims to uncover the potential of compound 8b in relation to apoptosis as well as autophagy induction in lung adenocarcinoma cells. STUDY DESIGN: The cytotoxicity and apoptosis of A549 and H1299 cells induced by compound 8b were detected by MTT, microscope and western blot analysis. Autophagy was determined by TEM, confocal microscopy and western blot analysis. Akt/mTOR and Erk signaling pathway were also examined by western blot analysis. RESULTS: First, significant growth inhibition and caspase-dependent apoptosis were observed in compound 8b-treated A549 and H1299 cells. Then, we confirmed compound 8b-induced autophagy by autophagosomes formation, upregulated expression of autophagy-related protein LC3-II and autophagic flux. Importantly, abolishing autophagy using inhibitors and ATG5 siRNA enhanced the cytotoxicity of compound 8b, indicating the cytoprotective role of autophagy in lung adenocarcinoma. Further mechanistic investigations suggested that Akt/mTOR and Erk signaling pathways contributed to autophagy induction by compound 8b. CONCLUSION: This results demonstrate that compound 8b induces caspase-dependent apoptosis as well as cytoprotective autophagy in lung adenocarcinoma cells, which may provide scientific evidence for developing this furoxan-based NO-releasing coumarin derivative as a potential anti-lung adenocarcinoma therapeutic agents.

An efficient production of high-pure xylooligosaccharides from corncob with affinity adsorption-enzymatic reaction integrated approach.

Xylooligosaccharides (XOS) are high value-added ingredients for functional foods and they have potential use as prebiotics. In order to reduce the production cost of XOS, we constructed a fusion enzyme consisting of expansin and endo-xylanase from B. subtilis Lucky9 to produce high-pure XOS with affinity adsorption-enzymatic reaction integrated approach. By optimization of inserting linker, the specific xylanase activity of fusion enzyme with R2 linker was increased 1.28-fold than that of native xylanase. Electrophoretic pure fusion enzyme was separated from crude enzyme extracts by affinity adsorption on corncob substrate, with 90.3% recovery in optimized conditions. Then, the fusion enzyme-corncob mixture was directly hydrolyzed. The yield of XOS reached 6.91mg/mL. The production of XOS with high purity of 91.7% was obtained by one step of centrifugation. This affinity adsorption-enzymatic reaction integrated XOS production approach provides a green route to alternative XOS traditional enzymatic production.

Extracellular expression of alkali tolerant xylanase from Bacillus subtilis Lucky9 in E. coli and application for xylooligosaccharides production from agro-industrial waste.

An alkali tolerant xylanase gene from Bacillus subtilis Lucky9 was cloned and extracellular expressed in E. coli BL21. Xylanase amino acid sequence showed 99% identity with xylanase sequence from Bacillus subtilis 168, and was belonged to glycoside hydrolase family 11. The recombinant E. coli (pET-pelB-xynLC9) containing pelB signal peptide produced extracellular xylanase of 436.5U/mL for 8h, which was used arabinose as extra carbon source and inducer for enhancing extracellular production. The extracellular xylanase was determined by SDS-PAGE with a relative molecular mass of 21kDa. The recombinant xylanase was optimally activity at pH 6.5 and 60°C. The xylanase exhibited 80% residual activity over a broad pH range of 6.0-9.0 for 24h. Thermostability studies showed that xylanase retained 60% residual activity after 2h at 60°C. The main end-products of hydrolysis of beech-wood xylan and corncob by the extracellular xylanase were xylobiose and xylotriose. This extracellular xylanase without purification is a suitable candidate for application in the industrial production of xylooligosaccharides from agro-industrial waste for use as prebiotics.

Cd47-Sirpα interaction and IL-10 constrain inflammation-induced macrophage phagocytosis of healthy self-cells.

Rapid clearance of adoptively transferred Cd47-null (Cd47(-/-)) cells in congeneic WT mice suggests a critical self-recognition mechanism, in which CD47 is the ubiquitous marker of self, and its interaction with macrophage signal regulatory protein α (SIRPα) triggers inhibitory signaling through SIRPα cytoplasmic immunoreceptor tyrosine-based inhibition motifs and tyrosine phosphatase SHP-1/2. However, instead of displaying self-destruction phenotypes, Cd47(-/-) mice manifest no, or only mild, macrophage phagocytosis toward self-cells except under the nonobese diabetic background. Studying our recently established Sirpα-KO (Sirpα(-/-)) mice, as well as Cd47(-/-) mice, we reveal additional activation and inhibitory mechanisms besides the CD47-SIRPα axis dominantly controlling macrophage behavior. Sirpα(-/-) mice and Cd47(-/-) mice, although being normally healthy, develop severe anemia and splenomegaly under chronic colitis, peritonitis, cytokine treatments, and CFA-/LPS-induced inflammation, owing to splenic macrophages phagocytizing self-red blood cells. Ex vivo phagocytosis assays confirmed general inactivity of macrophages from Sirpα(-/-) or Cd47(-/-) mice toward healthy self-cells, whereas they aggressively attack toward bacteria, zymosan, apoptotic, and immune complex-bound cells; however, treating these macrophages with IL-17, LPS, IL-6, IL-1ß, and TNFα, but not IFNγ, dramatically initiates potent phagocytosis toward self-cells, for which only the Cd47-Sirpα interaction restrains. Even for macrophages from WT mice, phagocytosis toward Cd47(-/-) cells does not occur without phagocytic activation. Mechanistic studies suggest a PKC-Syk-mediated signaling pathway, to which IL-10 conversely inhibits, is required for activating macrophage self-targeting, followed by phagocytosis independent of calreticulin Moreover, we identified spleen red pulp to be one specific tissue that provides stimuli constantly activating macrophage phagocytosis albeit lacking in Cd47(-/-) or Sirpα(-/-) mice.

Synthesis and antitumor evaluation of novel hybrids of phenylsulfonylfuroxan and epiandrosterone/dehydroepiandrosterone derivatives.

Thirteen novel furoxan-based nitric oxide (NO) releasing hybrids (14a-e, 15a-e, 17b-d) of 16,17-pyrazo-annulated steroidal derivatives were synthesized and evaluated against the MDA-MB-231, HCC1806, SKOV-3, DU145, and HUVEC cell lines for their in vitro anti-proliferative activity. Most of the compounds displayed potent anti-proliferative effects. Among them, 17c exhibited the best activity with IC50 values of 20-1.4nM against four cell lines (MDA-MB-231, SKOV-3, DU145, and HUVEC), and 1.03µM against a tamoxifen resistant breast cancer cell line (HCC1806). Furthermore, five compounds (14a, 15a, 17b-d) were selected to screen for VEGF inhibitory activity. Compounds 15a, 17b,c showed obviously better activity than 2-Methoxyestradiol (2-ME) on reducing levels of VEGF secreted by MDA-MB-231 cell line. In a Capillary-like Tube Formation Assay, compounds 17b,c exhibited a significant suppression of the tubule formation in the concentration of 1.75nM and 58nM, respectively. The preliminary SAR showed that steroidal scaffolds with a linker in 3-position were favorable moieties to evidently increase the bioactivities of these hybrids. Overall, these results implied that 17c merited to be further investigated as a promising anti-cancer candidate.

Hybrids of phenylsulfonylfuroxan and coumarin as potent antitumor agents.

Sixteen furoxan-based nitric oxide (NO) releasing coumarin derivatives (6a-c, 8a-g, 10a, 13a,b, 15, and 17a,b) were designed, synthesized, and evaluated against the A549, HeLa, A2780, A2780/CDDP, and HUVEC cell lines. Most derivatives displayed potent antiproliferation activities. Among them, 8b exhibited the strongest antiproliferation activity on the four sensitive cell lines mentioned above and three drug resistant tumor cell lines A2780/CDDP, MDA-MB-231/Gem, and SKOV3/CDDP with IC50 values from 14 to 53 nM and from 62 to 140 nM, respectively. Furthermore, 8b inhibited the growth of A2780 in vivo and displayed lower toxicity on nontumorigenesis T29, showing good selectivity against malignant cells in vitro. Preliminary pharmacological studies showed that 8b induces apoptosis, arrests the cell cycle at the G2/M phase in the A2780 cell line, and disrupts the phosphorylation of MEK1 and ERK1. Overall, the NO-releasing capacity and the inhibition of ERK/MAPK pathway signaling may explain the potent antineoplastic activity of these compounds.

Inflammation-induced proteolytic processing of the SIRPα cytoplasmic ITIM in neutrophils propagates a proinflammatory state.

Signal regulatory protein α (SIRPα), an immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing receptor, is an essential negative regulator of leukocyte inflammatory responses. Here we report that SIRPα cytoplasmic signalling ITIMs in neutrophils are cleaved during active inflammation and that the loss of SIRPα ITIMs enhances the polymorphonuclear leukocyte (PMN) inflammatory response. Using human leukocytes and two inflammatory models in mice, we show that the cleavage of SIRPα ITIMs in PMNs but not monocytes occurs at the post-acute stage of inflammation and correlates with increased PMN recruitment to inflammatory loci. Enhanced transmigration of PMNs and PMN-associated tissue damage are confirmed in mutant mice expressing SIRPα but lacking the ITIMs. Moreover, the loss of SIRPα ITIMs in PMNs during colitis is blocked by an anti-interleukin-17 (IL-17) antibody. These results demonstrate a SIRPα-based mechanism that dynamically regulates PMN inflammatory responses by generating a CD47-binding but non-signalling SIRPα 'decoy'.

CD47 deficiency does not impede polymorphonuclear neutrophil transmigration but attenuates granulopoiesis at the postacute stage of colitis.

Previous studies have suggested that CD47, an essential cell-surface protein, plays an important role in polymorphonuclear neutrophil (PMN) transmigration across tissue cells and extracellular matrix. In the current study, the role of CD47 in PMN transmigration and infiltration into tissues was further evaluated by investigating the function of CD47(-/-) PMN and inflammatory conditions induced in CD47(-/-) mice. Using in vitro time-course assays, we found that CD47(-/-) PMN exhibited no impediment, but slightly enhanced response to and transmigration toward, the chemoattractant fMLF. In vivo analysis in CD47(-/-) mice by inducing acute peritonitis and aggressive colitis observed consistent results, indicating that both PMN and monocytes effectively infiltrated inflammatory sites despite the absence of CD47 on these leukocytes or the surrounding tissue cells. Although PMN transmigration was not delayed in CD47(-/-) mice, fewer PMN were found in the intestine at the postacute/chronic stage of chronic colitis induced with sustained low-dose dextran sulfate sodium. Further analysis suggested that the paucity of PMN accumulation was attributable to attenuated granulopoiesis secondary to assessed lower levels of IL-17. Administration of exogenous IL-17A markedly increased PMN availability and rapidly rendered severe colitis in CD47(-/-) mice under dextran sulfate sodium treatment.

Regulation of the inflammatory response: enhancing neutrophil infiltration under chronic inflammatory conditions.

Neutrophil (polymorphonuclear leukocytes [PMN]) infiltration plays a central role in inflammation and is also a major cause of tissue damage. Thus, PMN infiltration must be tightly controlled. Using zymosan-induced peritonitis as an in vivo PMN infiltration model, we show in this study that PMN response and infiltration were significantly enhanced in mice experiencing various types of systemic inflammation, including colitis and diabetes. Adoptive transfer of leukocytes from mice with inflammation into healthy recipients or from healthy into inflammatory recipients followed by inducing peritonitis demonstrated that both circulating PMN and tissue macrophages were altered under inflammatory conditions and that they collectively contributed to enhanced PMN infiltration. Detailed analyses of dextran sulfate sodium-elicited colitis revealed that enhancement of PMN infiltration and macrophage function occurred only at the postacute/chronic phase of inflammation and was associated with markedly increased IL-17A in serum. In vitro and ex vivo treatment of isolated PMN and macrophages confirmed that IL-17A directly modulates these cells and significantly enhances their inflammatory responses. Neutralization of IL-17A eliminated the enhancement of PMN infiltration and IL-6 production and also prevented severe tissue damage in dextran sulfate sodium-treated mice. Thus, IL-17A produced at the chronic stage of colitis serves as an essential feedback signal that enhances PMN infiltration and promotes inflammation.

Cleavage of the CD11b extracellular domain by the leukocyte serprocidins is critical for neutrophil detachment during chemotaxis.

The ß(2)-integrin CD11b/CD18 mediates the firm adhesion of neutrophils (PMNs) to epithelial monolayers, a key step in PMN transepithelial migration. To complete the transmigration process, adherent PMNs must detach from epithelial monolayer surfaces to move forward. The mechanism that governs the detachment of adherent PMNs, however, is not clear. Here, we present evidence that cleavage of the CD11b extracellular domain containing the ligand-binding I-domain by 3 structural and functional related serine proteases (elastase, proteinase-3 and cathepsin G) serves as a novel mechanism for PMN detachment after the initial cell adhesion. Kinetic studies showed that the cleavage of CD11b is positively correlated with PMN detachment and subsequent transmigration. Moreover, the results demonstrated that elastase, proteinase-3 and cathepsin G all cleaved the purified, functionally active form of CD11b in a pattern similar to the CD11b shedding that occurs during PMN transmigration. Their cleavage sites on purified CD11b were located at (761)Thr-Ala(762) (elastase/proteinase-3) and (760)Phe-Thr(761) (cathepsin G), respectively. CD11b cleavage and PMN detachment and chemotaxis, were impaired in elastase/cathepsin G-deficient Beige mice; this defect could be restored by the addition of extracellular elastase. By illustrating CD11b shedding by elastase, proteinase-3 and cathepsin G as a novel mechanism for PMN detachment, our study provides novel therapeutic targets for controlling inflammation.

Control of secondary granule release in neutrophils by Ral GTPase.

Neutrophil (polymorphonuclear leukocyte; PMN) inflammatory functions, including cell adhesion, diapedesis, and phagocytosis, are dependent on the mobilization and release of various intracellular granules/vesicles. In this study, we found that treating PMN with damnacanthal, a Ras family GTPase inhibitor, resulted in a specific release of secondary granules but not primary or tertiary granules and caused dysregulation of PMN chemotactic transmigration and cell surface protein interactions. Analysis of the activities of Ras members identified Ral GTPase as a key regulator during PMN activation and degranulation. In particular, Ral was active in freshly isolated PMN, whereas chemoattractant stimulation induced a quick deactivation of Ral that correlated with PMN degranulation. Overexpression of a constitutively active Ral (Ral23V) in PMN inhibited chemoattractant-induced secondary granule release. By subcellular fractionation, we found that Ral, which was associated with the plasma membrane under the resting condition, was redistributed to secondary granules after chemoattractant stimulation. Blockage of cell endocytosis appeared to inhibit Ral translocation intracellularly. In conclusion, these results demonstrate that Ral is a critical regulator in PMN that specifically controls secondary granule release during PMN response to chemoattractant stimulation.

Role of microRNA-214-targeting phosphatase and tensin homolog in advanced glycation end product-induced apoptosis delay in monocytes.

Advanced glycation end products (AGEs) delay spontaneous apoptosis of monocytes and contribute to the development of inflammatory responses. However, the mechanism by which AGEs affect monocyte apoptosis is unclear. We studied the role of microRNA-214 (miR-214) and its target gene in AGE-induced monocytic apoptosis delay. Using microRNA (miRNA) microarray and stem-loop, quantitative RT-PCR assay, we studied genome-wide miRNA expression in THP-1 cells treated with or without AGEs. Significant upregulation of miR-214 was consistently observed in THP-1 and human monocytes treated with various AGEs, and AGE-induced monocytic miR-214 upregulation was likely through activation of receptor for AGEs. A striking increase in miR-214 was also detected in monocytes from patients with chronic renal failure. Luciferase reporter assay showed that miR-214 specifically binds to the phosphatase and tensin homolog (PTEN) mRNA 3'-untranslated region, implicating PTEN as a target gene of miR-214. PTEN expression is inversely correlated with miR-214 level in monocytes. Compared with normal monocytes, AGE-treated monocytes and monocytes from chronic renal failure patients exhibited lower PTEN levels and delayed apoptosis. Overexpression of pre-miR-214 led to impaired PTEN expression and delayed apoptosis of THP-1 cells, whereas knockdown of miR-214 level largely abolished AGE-induced cell survival. Our findings define a new role for miR-214-targeting PTEN in AGE-induced monocyte survival.

Uncoupling protein-2 negatively regulates polymorphonuclear leukocytes chemotaxis via modulating [Ca2+] influx.

OBJECTIVE: Previous studies demonstrated that uncoupling protein 2 (UCP2) plays a negative role in modulating leukocyte inflammatory responses. The mechanism underneath the role of UCP2 in modulating leukocyte inflammatory responses, however, is incompletely understood. Here, we investigated the effect of UCP2 in polymorphonuclear leukocyte (PMN) chemotaxis. METHODS AND RESULTS: First, we assessed PMN chemotaxis in zymosan-induced murine peritonitis and found that UCP2(-/-) mice had significantly more migrated PMN in peritoneal lavage compared to their wild-type littermates. In vitro transmigration assays using isolated PMN also showed that PMN from UCP2(-/-) mice migrated faster than those from wild-type mice in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP). Second, in supporting an inhibitory role of UCP2 in PMN transmigration, migrated PMN had a decreased UCP2 expression compared to nonmigrated PMN. In contrast, in streptozotocin-induced diabetic mice in which UCP2 expression was enhanced, PMN chemotaxis was reduced. Third, comparing to UCP2(+/+) PMN, UCP2(-/-) PMN had a stronger upregulation of fMLP-induced surface CD11b/CD18 and CD11a/CD18. Finally, UCP2(-/-) PMN showed a quicker and larger fMLP-triggered intracellular calcium mobilization compared to UCP2(+/+) PMN. CONCLUSIONS: Our study demonstrates that UCP2 serves as a brake in controlling PMN chemotaxis and that the effect of UCP2 on PMN chemotaxis may be through modulating calcium influx.