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1.  Preserving low perfusion during surgical liver blood inflow control prevents hepatic microcirculatory dysfunction and irreversible hepatocyte injury in rats 
Scientific Reports  2015;5:14406.
Hepatic ischaemia/reperfusion (I/R) injury is of primary concern during liver surgery. We propose a new approach for preserving low liver blood perfusion during hepatectomy either by occlusion of the portal vein (OPV) while preserving hepatic artery flow or occlusion of the hepatic artery while limiting portal vein (LPV) flow to reduce I/R injury. The effects of this approach on liver I/R injury were investigated. Rats were randomly assigned into 4 groups: sham operation, occlusion of the portal triad (OPT), OPV and LPV. The 7-day survival rate was significantly improved in the OPV and LPV groups compared with the OPT group. Microcirculatory liver blood flow recovered rapidly after reperfusion in the OPV and LPV groups but decreased further in the OPT group. The OPV and LPV groups also showed much lower ALT and AST levels, Suzuki scores, inflammatory gene expression levels, and parenchymal necrosis compared with the OPT group. An imbalance between the expression of vasoconstriction and vasodilation genes was observed in the OPT group but not in the OPV or LPV group. Therefore, preserving low liver blood perfusion by either the OPV or LPV methods during liver surgery is very effective for preventing hepatic microcirculatory dysfunction and hepatocyte injury.
PMCID: PMC4585878  PMID: 26400669
2.  Myeloperoxidase-oxidized high density lipoprotein impairs atherosclerotic plaque stability by inhibiting smooth muscle cell migration 
High density lipoprotein (HDL) has been proved to be a protective factor for coronary heart disease. Notably, HDL in atherosclerotic plaques can be nitrated (NO2-oxHDL) and chlorinated (Cl-oxHDL) by myeloperoxidase (MPO), likely compromising its cardiovascular protective effects.
Here we determined the effects of NO2-oxHDL and Cl-oxHDL on SMC migration using wound healing and transwell assays, proliferation using MTT and BrdU assays, and apoptosis using Annexin-V assay in vitro, as well as on atherosclerotic plaque stability in vivo using a coratid artery collar implantation mice model.
Our results showed that native HDL promoted SMC proliferation and migration, whereas NO2-oxHDL and Cl-oxHDL inhibited SMC migration and reduced capacity of stimulating SMC proliferation as well as migration, respectively. OxHDL had no significant influence on SMC apoptosis. In addition, we found that ERK1/2-phosphorylation was significantly lower when SMCs were incubated with NO2-oxHDL and Cl-oxHDL. Furthermore, transwell experiments showed that differences between native HDL, NO2-oxHDL and Cl-oxHDL was abolished after PD98059 (MAPK kinase inhibitor) treatment. In aortic SMCs from scavenger receptor BI (SR-BI) deficient mice, differences between migration of native HDL, NO2-oxHDL and Cl-oxHDL treated SMCs vanished, indicating SR-BI’s possible role in HDL-associated SMC migration. Importantly, NO2-oxHDL and Cl-oxHDL induced neointima formation and reduced SMC positive staining cells in atherosclerotic plaque, resulting in elevated vulnerable index of atherosclerotic plaque.
These findings implicate MPO-catalyzed oxidization of HDL may contribute to atherosclerotic plaque instability by inhibiting SMC proliferation and migration through MAPK-ERK pathway which was dependent on SR-BI.
Electronic supplementary material
The online version of this article (doi:10.1186/s12944-016-0388-z) contains supplementary material, which is available to authorized users.
PMCID: PMC5223295  PMID: 28069011
HDL; Smooth muscle cell; Atherosclerosis; Protein kinases/MAP kinase; MPO; Migration; Proliferation
3.  The impact of spectral filtration on image quality in micro-CT system 
This paper aims to evaluate the impact of spectral filtration on image quality in a microcomputed tomography (micro-CT) system. A mouse phantom comprising 11 rods for modeling lung, muscle, adipose, and bones was scanned with 17 s and 2 min, respectively. The current (µA) for each scan was adjusted to achieve identical entrance exposure to the phantom, providing a baseline for image quality evaluation. For each region of interest (ROI) within specific composition, CT number variations, noise levels, and contrast-to-noise ratios (CNRs) were evaluated from the reconstructed images. CT number variations and CNRs for bone with high density, muscle, and adipose were compared with theoretical predictions. The results show that the impact of spectral filtration on image quality indicators, such as CNR in a micro-CT system, is significantly associated with tissue characteristics. The findings may provide useful references for optimizing the scanning parameters of general micro-CT systems in future imaging applications.
PMCID: PMC4762071  PMID: 26894340
spectral filtration; image quality; microcomputed tomography (micro-CT); contrast-to-noise ratio (CNR); tissue characteristic
4.  Study on relationship between pollen exine ornamentation pattern and germplasm evolution in flowering crabapple 
Scientific Reports  2017;7:39759.
Pollen ornamentation patterns are important in the study of plant genetic evolution and systematic taxonomy. However, they are normally difficult to quantify. Based on observations of pollen exine ornamentation characteristics of 128 flowering crabapple germplasms (44 natural species and 84 varieties), three qualitative variables with binary properties (Xi: regularity of pollen exine ornamentation; Yi: scope of ornamentation arrangement regularity; Zi: ornamentation arrangement patterns) were extracted to establish a binary three-dimensional data matrix (Xi Yi Zi) and the matrix data were converted to decimal data through weight assignment, which facilitated the unification of qualitative analysis and quantitative analysis. The result indicates that from species population to variety population and from parent population to variety population, the exine ornamentation of all three dimensions present the evolutionary trend of regular → irregular, wholly regular → partially regular, and single pattern → multiple patterns. Regarding the evolutionary degree, the regularity of ornamentation was significantly lower in both the variety population and progeny population, with a degree of decrease 0.82–1.27 times that of the regularity range of R-type ornamentation. In addition, the evolutionary degree significantly increased along Xi  → Yi → Zi. The result also has certain reference values for defining the taxonomic status of Malus species.
PMCID: PMC5216378  PMID: 28059122
5.  Anti-arthritic activity of ethanol extract of Claoxylon indicum on Freund’s complete adjuvant-induced arthritis in mice 
Claoxylon indicum Hassk. (Euphorbiaceae), named Diu Le Bang, have functions of dehumidification and relieving swelling pain, and is used as a folk medicine to treat Rheumatoid arthritis (RA), lumbocrural pain and foot edema in the south of China. The aim of the present study was to investigate the anti-arthritic activity of the ethanol extract of Claoxylon indicum (CIE) on mice with adjuvant induced joint arthritis.
Adjuvant arthritis was induced in mice by subcutaneous injection of complete Freund’s adjuvant into the plantar surface of right hind paw. Arthritis severity was evaluated by arthritic score, hind paws oedema and spleen index, and histological examinations. Serum samples were collected for determination of malondialdehyde (MDA) and alkaline phosphatase (ALP) levels. The expression of interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in the specimens of knee joints was determined by standard immunohistochemical techniques.
CIE administration (0.4 and 0.8 g/kg) suppressed the inflammatory responses in the joints of adjuvant-induced arthritis (AIA) mice, suggested by the modulatory effects on paw swelling, hyperplasia of lymphatic tissues and synovial membrane. It also decreased the levels of MDA and ALP in serum and downregulated the expression of IL-1β and TNF-α in the arthritic joints of AIA mice.
These results suggested that CIE possessed substantial anti-arthritic activity due to immumodepression and regulation of cytokines. CIE may be a potential candidate for the treatment of RA.
PMCID: PMC5216541  PMID: 28056924
Claoxylon indicum; Rheumatoid arthritis (RA); Adjuvant arthritis; Inflammation
6.  High-Affinity, Small-Molecule Peptidomimetic Inhibitors of MLL1/WDR5 Protein–Protein Interaction 
Mixed lineage leukemia 1 (MLL1) is a histone H3 lysine 4 (H3K4) methyltransferase, and targeting the MLL1 enzymatic activity has been proposed as a novel therapeutic strategy for the treatment of acute leukemia harboring MLL1 fusion proteins. The MLL1/WDR5 protein–protein interaction is essential for MLL1 enzymatic activity. In the present study, we designed a large number of peptidomimetics to target the MLL1/WDR5 interaction based upon –CO-ARA-NH–, the minimum binding motif derived from MLL1. Our study led to the design of high-affinity peptidomimetics, which bind to WDR5 with Ki < 1 nM and function as potent antagonists of MLL1 activity in a fully reconstituted in vitro H3K4 methyltransferase assay. Determination of co-crystal structures of two potent peptidomimetics in complex with WDR5 establishes their structural basis for high-affinity binding to WDR5. Evaluation of one such peptidomimetic, MM-102, in bone marrow cells transduced with MLL1-AF9 fusion construct shows that the compound effectively decreases the expression of HoxA9 and Meis-1, two critical MLL1 target genes in MLL1 fusion protein mediated leukemogenesis. MM-102 also specifically inhibits cell growth and induces apoptosis in leukemia cells harboring MLL1 fusion proteins. Our study provides the first proof-of-concept for the design of small-molecule inhibitors of the WDR5/MLL1 protein–protein interaction as a novel therapeutic approach for acute leukemia harboring MLL1 fusion proteins.
Graphical abstract
PMCID: PMC5180416  PMID: 23210835
7.  Lrp4 in astrocytes modulates glutamatergic transmission 
Nature neuroscience  2016;19(8):1010-1018.
Neurotransmission requires precise control of neurotransmitter release from axon terminals. This process is regulated by glial cells; however, underlying mechanisms are not fully understood. Here we report that glutamate release in the brain is impaired in mice lacking low density lipoprotein receptor-related protein 4 (Lrp4), a protein critical for neuromuscular junction formation. Electrophysiological studies indicate compromised release probability in astrocyte-specific Lrp4 knockout mice. Lrp4 mutant astrocytes suppress glutamate transmission by enhancing the release of ATP, whose levels are elevated in the hippocampus of Lrp4 mutant mice. Consequently, the mutant mice are impaired in locomotor activity and spatial memory and are resistant to seizure induction. These impairments could be ameliorated by adenosine A1 receptor antagonist. The results reveal a critical role of Lrp4, in response to agrin, in modulating astrocytic ATP release and synaptic transmission. Our study provides insight into the interaction between neurons and astrocytes for synaptic homeostasis and/or plasticity.
PMCID: PMC4961622  PMID: 27294513
8.  Natural Endogenous Human Matriptase and Prostasin Undergo Zymogen Activation via Independent Mechanisms in an Uncoupled Manner 
PLoS ONE  2016;11(12):e0167894.
The membrane-associated serine proteases matriptase and prostasin are believed to function in close partnership. Their zymogen activation has been reported to be tightly coupled, either as a matriptase-initiated proteolytic cascade or through a mutually dependent mechanism involving the formation of a reciprocal zymogen activation complex. Here we show that this putative relationship may not apply in the context of human matriptase and prostasin. First, the tightly coupled proteolytic cascade between matriptase and prostasin might not occur when modest matriptase activation is induced by sphingosine 1-phospahte in human mammary epithelial cells. Second, prostasin is not required and/or involved in matriptase autoactivation because matriptase can undergo zymogen activation in cells that do not endogenously express prostasin. Third, matriptase is not required for and/or involved in prostasin activation, since activated prostasin can be detected in cells expressing no endogenous matriptase. Finally, matriptase and prostasin both undergo zymogen activation through an apparently un-coupled mechanism in cells endogenously expressing both proteases, such as in Caco-2 cells. In these human enterocytes, matriptase is detected primarily in the zymogen form and prostasin predominantly as the activated form, either in complexes with protease inhibitors or as the free active form. The negligible levels of prostasin zymogen with high levels of matriptase zymogen suggests that the reciprocal zymogen activation complex is likely not the mechanism for matriptase zymogen activation. Furthermore, high level prostasin activation still occurs in Caco-2 variants with reduced or absent matriptase expression, indicating that matriptase is not required and/or involved in prostasin zymogen activation. Collectively, these data suggest that any functional relationship between natural endogenous human matriptase and prostasin does not occur at the level of zymogen activation.
PMCID: PMC5148038  PMID: 27936035
9.  Free-Breathing Liver Perfusion Imaging Using 3D Through-Time Spiral GRAPPA Acceleration 
Investigative radiology  2015;50(6):367-375.
The goal of this study is to develop free-breathing high spatiotemporal resolution DCE liver MRI using non-Cartesian parallel imaging acceleration, and quantitative liver perfusion mapping.
Materials and Methods
This study is HIPAA-compliant, IRB approved, and written informed consent was obtained from all participants. Ten healthy subjects and five patients were scanned on a Siemens 3T Skyra scanner. A stack-of-spirals trajectory was undersampled in-plane with a reduction factor of 6, and reconstructed using 3D through-time non-Cartesian GRAPPA. High resolution 3D images were acquired with a true temporal resolution of 1.6~1.9 seconds, while the subjects were breathing freely. A dual-input single-compartment model was used to retrieve liver perfusion parameters from DCE-MRI data, which were co-registered using an algorithm designed to reduce the effects of dynamic contrast changes on registration. Image quality evaluation was performed on spiral images and conventional images from five healthy subjects.
Images with a spatial resolution of 1.9×1.9×3 mm3 were obtained with whole liver coverage. With an imaging speed of better than 2 sec/volume, free-breathing scans were achieved, and dynamic changes in enhancement were captured. The overall image quality of free-breathing spiral images was slightly lower than conventional long breath-hold Cartesian images, but provided clinical acceptable or better image quality. The free-breathing 3D images were registered with almost no residual motion in liver tissue. Following the registration, quantitative whole liver 3D perfusion maps were obtained and the perfusion parameters are all in good agreement with the literature.
This high spatiotemporal resolution free-breathing 3D liver imaging technique allows voxel-wise quantification of liver perfusion.
PMCID: PMC4423561  PMID: 25946703
liver perfusion; through-time spiral GRAPPA; DCE MRI
10.  AS1411-Induced Growth Inhibition of Glioma Cells by Up-Regulation of p53 and Down-Regulation of Bcl-2 and Akt1 via Nucleolin 
PLoS ONE  2016;11(12):e0167094.
AS1411 binds nucleolin (NCL) and is the first oligodeoxynucleotide aptamer to reach phase I and II clinical trials for the treatment of several cancers. However, the mechanisms by which AS1411 targets and kills glioma cells and tissues remain unclear. Here we report that AS1411 induces cell apoptosis and cycle arrest, and inhibits cell viability by up-regulation of p53 and down-regulation of Bcl-2 and Akt1 in human glioma cells. NCL was overexpressed in both nucleus and cytoplasm in human glioma U87, U251 and SHG44 cells compared to normal human astrocytes (NHA). AS1411 bound NCL and inhibited the proliferation of glioma cells but not NHA, which was accompanied with up-regulation of p53 and down-regulation of Bcl-2 and Akt1. Moreover, AS1411 treatment resulted in the G2/M cell cycle arrest in glioma cells, which was however abolished by overexpression of NCL. Further, AS1411 induced cell apoptosis, which was prevented by silencing of p53 and overexpression of Bcl-2. In addition, AS1411 inhibited the migration and invasion of glioma cells in an Akt1-dependent manner. Importantly, AS1411 inhibited the growth of glioma xenograft and prolonged the survival time of glioma tumor-bearing mice. These results revealed a promising treatment of glioma by oligodeoxynucleotide aptamer.
PMCID: PMC5132312  PMID: 27907160
11.  Self-healing polysaccharide-based hydrogels as injectable carriers for neural stem cells 
Scientific Reports  2016;6:37841.
Self-healing injectable hydrogels can be formulated as three-dimensional carriers for the treatment of neurological diseases with desirable advantages, such as avoiding the potential risks of cell loss during injection, protecting cells from the shearing force of injection. However, the demands for biocompatible self-healing injectable hydrogels to meet above requirements and to promote the differentiation of neural stem cells (NSCs) into neurons remain a challenge. Herein, we developed a biocompatible self-healing polysaccharide-based hydrogel system as a novel injectable carrier for the delivery of NSCs. N-carboxyethyl chitosan (CEC) and oxidized sodium alginate (OSA) are the main backbones of the hydrogel networks, denoted as CEC-l-OSA hydrogel (“l” means “linked-by”). Owing to the dynamic imine cross-links formed by a Schiff reaction between amino groups on CEC and aldehyde groups on OSA, the hydrogel possesses the ability to self-heal into a integrity after being injected from needles under physiological conditions. The CEC-l-OSA hydrogel in which the stiffness mimicking nature brain tissues (100~1000 Pa) can be finely tuned to support the proliferation and neuronal differentiation of NSCs. The multi-functional, injectable, and self-healing CEC-l-OSA hydrogels hold great promises for NSC transplantation and further treatment of neurological diseases.
PMCID: PMC5126669  PMID: 27897217
12.  Structural basis for activity regulation of MLL family methyltransferases 
Nature  2016;530(7591):447-452.
The mixed lineage leukaemia (MLL) family of proteins (including MLL1–MLL4, SET1A and SET1B) specifically methylate histone 3 Lys4, and have pivotal roles in the transcriptional regulation of genes involved in haematopoiesis and development. The methyltransferase activity of MLL1, by itself severely compromised, is stimulated by the three conserved factors WDR5, RBBP5 and ASH2L, which are shared by all MLL family complexes. However, the molecular mechanism of how these factors regulate the activity of MLL proteins still remains poorly understood. Here we show that a minimized human RBBP5–ASH2L heterodimer is the structural unit that interacts with and activates all MLL family histone methyltransferases. Our structural, biochemical and computational analyses reveal a two-step activation mechanism of MLL family proteins. These findings provide unprecedented insights into the common theme and functional plasticity in complex assembly and activity regulation of MLL family methyltransferases, and also suggest a universal regulation mechanism for most histone methyltransferases.
PMCID: PMC5125619  PMID: 26886794
13.  Phosphorylation induces distinct alpha-synuclein strain formation 
Scientific Reports  2016;6:37130.
Synucleinopathies are a group of neurodegenerative diseases associated with alpha-synuclein (α-Syn) aggregation. Recently, increasing evidence has demonstrated the existence of different structural characteristics or ‘strains’ of α-Syn, supporting the concept that synucleinopathies share several common features with prion diseases and possibly explaining how a single protein results in different clinical phenotypes within synucleinopathies. In earlier studies, the different strains were generated through the regulation of solution conditions, temperature, or repetitive seeded fibrillization in vitro. Here, we synthesize homogeneous α-Syn phosphorylated at serine 129 (pS129 α-Syn), which is highly associated with the pathological changes, and demonstrate that phosphorylation at Ser129 induces α-Syn to form a distinct strain with different structures, propagation properties, and higher cytotoxicity compared with the wild-type α-Syn. The results are the first demonstration that post-translational modification of α-Syn can induce different strain formation, offering a new mechanism for strain formation.
PMCID: PMC5112567  PMID: 27853185
14.  Metabolic Engineering of Mortierella alpina for Enhanced Arachidonic Acid Production through the NADPH-Supplying Strategy 
Applied and Environmental Microbiology  2016;82(11):3280-3288.
NADPH is known to be a key cofactor required for fatty acid synthesis and desaturation. Various enzymatic reactions can generate NADPH. To determine the effect of NADPH sources on lipogenesis, glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (PGD), isocitrate dehydrogenase (IDH), and malic enzyme (ME) were overexpressed in Mortierella alpina. Our results showed that G6PD2 had the most significant effect on fatty acid synthesis, with a 1.7-fold increase in total fatty acid, whereas ME2 was more effective in desaturation, with a 1.5-fold increase in arachidonic acid (AA) content over control. Co-overexpression of G6PD2 and ME2 improved both fatty acid synthesis and desaturation. Within 96 h of fermentation using the fed-batch method, the co-overexpressing strain accumulated AA at a productivity of 1.9 ± 0.2 g/(liter · day), which was 7.2-fold higher than that in the M. alpina control that was cultured in a flask.
IMPORTANCE This study proved that the pentose phosphate pathway is the major NADPH contributor during fatty acid synthesis in M. alpina. The NADPH sources may be differently responsible for fatty acid synthesis or desaturation. Co-overexpression of G6PD2 and ME2 significantly increases AA production.
PMCID: PMC4959234  PMID: 27016571
15.  Transmission network of the 2014–2015 Ebola epidemic in Sierra Leone 
Journal of the Royal Society Interface  2015;12(112):20150536.
Understanding the growth and spatial expansion of (re)emerging infectious disease outbreaks, such as Ebola and avian influenza, is critical for the effective planning of control measures; however, such efforts are often compromised by data insufficiencies and observational errors. Here, we develop a spatial–temporal inference methodology using a modified network model in conjunction with the ensemble adjustment Kalman filter, a Bayesian inference method equipped to handle observational errors. The combined method is capable of revealing the spatial–temporal progression of infectious disease, while requiring only limited, readily compiled data. We use this method to reconstruct the transmission network of the 2014–2015 Ebola epidemic in Sierra Leone and identify source and sink regions. Our inference suggests that, in Sierra Leone, transmission within the network introduced Ebola to neighbouring districts and initiated self-sustaining local epidemics; two of the more populous and connected districts, Kenema and Port Loko, facilitated two independent transmission pathways. Epidemic intensity differed by district, was highly correlated with population size (r = 0.76, p = 0.0015) and a critical window of opportunity for containing local Ebola epidemics at the source (ca one month) existed. This novel methodology can be used to help identify and contain the spatial expansion of future (re)emerging infectious disease outbreaks.
PMCID: PMC4685836  PMID: 26559683
Ebola; transmission network; Bayesian inference; gravity model; ensemble adjustment Kalman filter
16.  Characterization of the cardiac succinylome and its role in ischemia-reperfusion injury 
Succinylation refers to modification of lysine residues with succinyl groups donated by succinyl-CoA. Sirtuin5 (Sirt5) is a mitochondrial NAD+-dependent deacylase that catalyzes the removal of succinyl groups from proteins. Sirt5 and protein succinylation are conserved across species, suggesting functional importance of the modification. Sirt5 loss impacts liver metabolism but the role of succinylation in the heart has not been explored. We combined affinity enrichment with proteomics and mass spectrometry to analyze total succinylated lysine content of mitochondria isolated from WT and Sirt5−/− mouse hearts. We identified 887 succinylated lysine residues in 184 proteins. 44 peptides (5 proteins) occurred uniquely in WT samples, 289 (46 proteins) in Sirt5−/− samples, and 554 (133 proteins) were common to both groups. The 46 unique proteins in Sirt5−/− heart participate in metabolic processes such as fatty acid β-oxidation (Eci2) and branched chain amino acid catabolism, and include respiratory chain proteins (Ndufa7, 12, 13, Dhsa). We performed label-free analysis of the peptides common to WT and Sirt5−/− hearts. 16 peptides from 9 proteins were significantly increased in Sirt5−/− by at least 30%. The adenine nucleotide transporter 1 showed the highest increase in succinylation in Sirt5−/− (108.4 fold). The data indicate that succinylation is widespread in the heart and enriched in metabolic pathways. We examined whether the loss of Sirt5 would impact ischemia-reperfusion (I/R) injury and we found an increase in infarct size in Sirt5−/− hearts compared to WT littermates (68.5+/− 1.1% Sirt5−/− vs 39.6+/− 6.8% WT) following 20 minutes of ischemia and 90 minutes reperfusion. We further demonstrate that I/R injury in Sirt5−/− heart is restored to WT levels by pretreatment with dimethyl malonate, a competitive inhibitor of succinate dehydrogenase (SDH), implicating alteration in SDH activity as causative of the injury.
PMCID: PMC4780049  PMID: 26388266
Sirt5; Ischemia-reperfusion; Cardiac; Succinylation; Succinate
17.  Changes of the Bacterial Abundance and Communities in Shallow Ice Cores from Dunde and Muztagata Glaciers, Western China 
In this study, six bacterial community structures were analyzed from the Dunde ice core (9.5-m-long) using 16S rRNA gene cloning library technology. Compared to the Muztagata mountain ice core (37-m-long), the Dunde ice core has different dominant community structures, with five genus-related groups Blastococcus sp./Propionibacterium, Cryobacterium-related., Flavobacterium sp., Pedobacter sp., and Polaromas sp. that are frequently found in the six tested ice layers from 1990 to 2000. Live and total microbial density patterns were examined and related to the dynamics of physical-chemical parameters, mineral particle concentrations, and stable isotopic ratios in the precipitations collected from both Muztagata and Dunde ice cores. The Muztagata ice core revealed seasonal response patterns for both live and total cell density, with high cell density occurring in the warming spring and summer months indicated by the proxy value of the stable isotopic ratios. Seasonal analysis of live cell density for the Dunde ice core was not successful due to the limitations of sampling resolution. Both ice cores showed that the cell density peaks were frequently associated with high concentrations of particles. A comparison of microbial communities in the Dunde and Muztagata glaciers showed that similar taxonomic members exist in the related ice cores, but the composition of the prevalent genus-related groups is largely different between the two geographically different glaciers. This indicates that the micro-biogeography associated with geographic differences was mainly influenced by a few dominant taxonomic groups.
PMCID: PMC5088206  PMID: 27847503
live cell density; taxonomic group; micro-biogeography; glacier; Tibet Plateau
18.  Carbon Balance and Contribution of Harvested Wood Products in China Based on the Production Approach of the Intergovernmental Panel on Climate Change 
The carbon sequestration of harvested wood products (HWP) plays an important role in climate mitigation. Accounting the carbon contribution of national HWP carbon pools has been listed as one of the key topics for negotiation in the United Nations Framework Convention on Climate Change. On the basis of the revised Production Approach of the Intergovernmental Panel on Climate Change (2013) (IPCC), this study assessed the accounting of carbon stock and emissions from the HWP pool in China and then analyzed its balance and contribution to carbon mitigation from 1960 to 2014. Research results showed that the accumulated carbon stock in China’s HWP carbon pool increased from 130 Teragrams Carbon (TgC) in 1960 to 705.6 TgC in 2014. The annual increment in the carbon stock rose from 3.2 TgC in 1960 to 45.2 TgC in 2014. The category of solid wood products accounted for approximately 95% of the annual amount. The reduction in carbon emissions was approximately twelve times that of the emissions from the HWP producing and processing stage during the last decade. Furthermore, the amount of carbon stock and emission reduction increased from 23 TgC in 1960 to 76.1 TgC in 2014. The annual contribution of HWP could compensate for approximately 2.9% of the national carbon dioxide emissions in China.
PMCID: PMC5129342  PMID: 27845760
IPCC framework; harvested wood products; carbon substitution; carbon balance
19.  Sulforaphane Protects Pancreatic Acinar Cell Injury by Modulating Nrf2-Mediated Oxidative Stress and NLRP3 Inflammatory Pathway 
Acute pancreatitis (AP) is characterized by early activation of intra-acinar proteases followed by acinar cell death and inflammation. Cellular oxidative stress is a key mechanism underlying these pathological events. Sulforaphane (SFN) is a natural organosulfur antioxidant with undescribed effects on AP. Here we investigated modulatory effects of SFN on cellular oxidation and inflammation in AP. AP was induced by cerulean hyperstimulation in BALB/c mice. Treatment group received a single dose of 5 mg/kg SFN for 3 consecutive days before AP. We found that SFN administration attenuated pancreatic injury as evidenced by serum amylase, pancreatic edema, and myeloperoxidase, as well as by histological examination. SFN administration reverted AP-associated dysregulation of oxidative stress markers including pancreatic malondialdehyde and redox enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx). In acinar cells, SFN treatment upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) expression and Nrf2-regulated redox genes including quinoneoxidoreductase-1, heme oxidase-1, SOD1, and GPx1. In addition, SFN selectively suppressed cerulein-induced activation of the nucleotide-binding domain leucine-rich repeat containing family, pyrin domain-containing 3 (NLRP3) inflammasome, in parallel with reduced nuclear factor- (NF-) κB activation and modulated NF-κB-responsive cytokine expression. Together, our data suggested that SFN modulates Nrf2-mediated oxidative stress and NLRP3/NF-κB inflammatory pathways in acinar cells, thereby protecting against AP.
PMCID: PMC5101394  PMID: 27847555
20.  Scalable and Sustainable Electrochemical Allylic C–H Oxidation 
Nature  2016;533(7601):77-81.
New methods and strategies for the direct functionalization of C–H bonds are beginning to reshape the fabric of retrosynthetic analysis, impacting the synthesis of natural products, medicines, and even materials1. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C–H functionalization due to the utility of enones and allylic alcohols as versatile intermediates, along with their prevalence in natural and unnatural materials2. Allylic oxidations have been featured in hundreds of syntheses, including some natural product syntheses regarded as “classics”3. Despite many attempts to improve the efficiency and practicality of this powerful transformation, the vast majority of conditions still employ highly toxic reagents (based around toxic elements such as chromium, selenium, etc.) or expensive catalysts (palladium, rhodium, etc.)2. These requirements are highly problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. As such, this oxidation strategy is rarely embraced for large-scale synthetic applications, limiting the adoption of this important retrosynthetic strategy by industrial scientists. In this manuscript, we describe an electrochemical solution to this problem that exhibits broad substrate scope, operational simplicity, and high chemoselectivity. This method employs inexpensive and readily available materials, representing the first example of a scalable allylic C–H oxidation (demonstrated on 100 grams), finally opening the door for the adoption of this C–H oxidation strategy in large-scale industrial settings without significant environmental impact.
PMCID: PMC4860034  PMID: 27096371
21.  PKA-mediated phosphorylation of Dexras1 suppresses iron trafficking by inhibiting S-nitrosylation 
FEBS letters  2015;589(20 0 0):3212-3219.
Dexras1 is a small GTPase and plays a central role in neuronal iron trafficking. We have shown that stimulation of glutamate receptors activates neuronal nitric oxide synthase, leading to S-nitrosylation of Dexras1 and a physiological increase in iron uptake. Here we report that Dexras1 is phosphorylated by PKA on serine 253, leading to a suppression of iron influx. These effects were directly associated with the levels of S-nitrosylated Dexras1, whereby PKA activation reduced Dexras1 S-nitrosylation in a dose dependent manner. Moreover, we found that adiponectin modulates Dexras1 via PKA. Hence these findings suggest the involvement of the PKA pathway in modulating glutamate-mediated ROS in neurons, and hint to a functional crosstalk between S-nitrosylation and phosphorylation.
PMCID: PMC4767167  PMID: 26358293
22.  Fat tissues, the brite and the dark sides 
Pflugers Archiv  2016;468(11):1803-1807.
Fat tissue is well known for its capacity to store energy and its detrimental role in obesity and metaflammation. However, humans possess different types of fat that have different functions in physiology and metabolic diseases. Apart from white adipose tissue (WAT), the body’s main energy storage, there is also brown adipose tissue (BAT) that dissipates energy as a defense against cold and maintains energy balance for the whole body. BAT is present not only in newborns but also in adult humans and its mass correlates with leanness. Moreover, “brown-like” adipocytes have been detected in human WAT. These “brown-in-white” (brite) or beige cells can be induced by cold and a broad spectrum of pharmacological substances and, therefore, they are also known as “inducible brown adipocytes.” Activation of brown and/or brite adipocytes reduces metabolic diseases, at least in murine models of obesity. Thus, brown/brite adipocytes represent the “brite” side of fat and are potential targets for novel therapeutic approaches for treatment of obesity and obesity-associated diseases.
PMCID: PMC5138267  PMID: 27704210
Metabolism; Obesity; Brown adipose tissue; Brite/beige adipocytes; Energy expenditure
23.  n-3 Polyunsaturated Fatty Acids and their Role in Cancer Chemoprevention 
Current pharmacology reports  2015;1(5):283-294.
Polyunsaturated fatty acids (PUFAs), including omega-3 (n-3) and omega-6 (n-6) PUFAs, are essential for human health. Recent research shows n-3 PUFAs and their mediators can inhibit inflammation, angiogenesis and cancer via multiple mechanisms, including reduced release of n-6 fatty acid arachidonic acid from cell membranes, inhibition of enzymatic activities, and direct competition with arachidonic acid for enzymatic conversions. In this review, we discuss inflammation-related cancer, anti-inflammatory effects of n-3 PUFA lipid mediators, antineoplastic activities of n-3 PUFA in vitro and in vivo, and present an update on recent human trials.
PMCID: PMC4596534  PMID: 26457243
n-3 polyunsaturated fatty acids; cancer; inflammation; chemotherapy; lipid mediator
25.  Improving methane production in cow dung and corn straw co-fermentation systems via enhanced degradation of cellulose by cabbage addition 
Scientific Reports  2016;6:33628.
The effects of cabbage waste (CW) addition on methane production in cow dung and corn straw co-fermentation systems were investigated. Four experimental groups, each containing 55 g of substrate, were set up as follows: 100% cow dung (C); 36% cabbage and 64% cow dung (CC); 36% straw and 64% cow dung (SC); and 18% cabbage, 18% straw, and 64% cow dung (CSC). After seven days of fermentation, the maximum methane yield was 134 mL in the CSC group, which was 2.81-fold, 1.78-fold, and 1340-fold higher than that obtained in the CC, SC, and C groups, respectively. CW treatment of the CSC group enhanced cellulase activity and enriched culturable cellulose-degrading bacterial strains. Miseq sequencing data revealed that the predominant phylum in the CSC group was Bacteroidetes, which contains most of the cellulose-degrading bacteria. Our results suggested that CW treatment elevated cellulose degradation and promoted methane production.
PMCID: PMC5027527  PMID: 27641709

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