Attention spotlight in V1-based cortico-cortical interactions in human visual hierarchy.

Attention is often viewed as a mental spotlight, which can be scaled like a zoom lens at specific spatial locations and features a center-surround gradient. Here, we demonstrate a neural signature of attention spotlight in signal transmission along the visual hierarchy. fMRI background connectivity analysis was performed between retinotopic V1 and downstream areas to characterize the spatial distribution of inter-areal interaction under two attentional states. We found that, compared to diffused attention, focal attention sharpened the spatial gradient in the strength of the background connectivity. Dynamic causal modeling analysis further revealed the effect of attention in both the feedback and feedforward connectivity between V1 and extrastriate cortex. In a context which induced a strong effect of crowding, the effect of attention in the background connectivity profile diminished. Our findings reveal a context-dependent attention prioritization in information transmission via modulating the recurrent processing across the early stages in human visual cortex.

Seeing in crowds: Averaging first, then max.

Crowding, a fundamental limit in object recognition, is believed to result from excessive integration of nearby items in peripheral vision. To understand its pooling mechanisms, we measured subjects' internal response distributions in an orientation crowding task. Contrary to the prediction of an averaging model, we observed a pattern suggesting that the perceptual judgement is made based on choosing the largest response across the noise-perturbed items. A model featuring first-stage averaging and second-stage signed-max operation predicts the diverse errors made by human observers under various signal strength levels. These findings suggest that different rules operate to resolve the bottleneck at early and high-level stages of visual processing, implementing a combination of linear and nonlinear pooling strategies.

Context-dependent attentional spotlight in pulvinar-V1 interaction.

Spatial attention is often described as a mental spotlight that enhances information processing at the attended location. Using fMRI, we investigated background connectivity between the pulvinar and V1 in relation to focused versus diffused attention allocation, in weak and strong crowding contexts. Our findings revealed that focused attention led to enhanced correlations between the pulvinar and V1. Notably, this modulation was initiated by the pulvinar, and the strength of the modulation was dependent on the saliency of the target. These findings suggest that the pulvinar initiates information reweighting to V1, which underlies attentional selection in cluttered scenes.

PDE4DIP contributes to colorectal cancer growth and chemoresistance through modulation of the NF1/RAS signaling axis.

Phosphodiesterase 4D interacting protein (PDE4DIP) is a centrosome/Golgi protein associated with cyclic nucleotide phosphodiesterases. PDE4DIP is commonly mutated in human cancers, and its alteration in mice leads to a predisposition to intestinal cancer. However, the biological function of PDE4DIP in human cancer remains obscure. Here, we report for the first time the oncogenic role of PDE4DIP in colorectal cancer (CRC) growth and adaptive MEK inhibitor (MEKi) resistance. We show that the expression of PDE4DIP is upregulated in CRC tissues and associated with the clinical characteristics and poor prognosis of CRC patients. Knockdown of PDE4DIP impairs the growth of KRAS-mutant CRC cells by inhibiting the core RAS signaling pathway. PDE4DIP plays an essential role in the full activation of oncogenic RAS/ERK signaling by suppressing the expression of the RAS GTPase-activating protein (RasGAP) neurofibromin (NF1). Mechanistically, PDE4DIP promotes the recruitment of PLCγ/PKCε to the Golgi apparatus, leading to constitutive activation of PKCε, which triggers the degradation of NF1. Upregulation of PDE4DIP results in adaptive MEKi resistance in KRAS-mutant CRC by reactivating the RAS/ERK pathway. Our work reveals a novel functional link between PDE4DIP and NF1/RAS signal transduction and suggests that targeting PDE4DIP is a promising therapeutic strategy for KRAS-mutant CRC.

RSPO2 promotes progression of ovarian cancer through dual receptor-mediated FAK/Src signaling activation.

R-spondin 2 (RSPO2) drives the potentiation of Wnt signaling and is implicated in tumorigenesis in multiple cancers, but its role in ovarian cancer has not been investigated. Here, we reported that RSPO2 promoted the growth and metastasis of ovarian cancer through the activation of FAK/Src signaling cascades. RSPO2 enhanced the autophosphorylation of FAK and Src through a unique dual receptors mechanism. First, RSPO2-LGR4 interaction prevented the endocytic degradation of LGR4 and promoted LGR4-mediated translocation of Src to the plasma membrane. Second, RSPO2 directly bound to integrin ß3 as a ligand and enhanced the stability of integrins, and both actions potentiated autoactivation of FAK and/or Src in ovarian cancer cells. RSPO2 expression was increased in ovarian tumors and was associated with poor prognosis in patients. Our study highlights the importance of RSPO2 in ovarian tumor progression and suggests that targeting RSPO2/FAK/Src cascades may constitute potential approaches to inhibit the progression of aggressive ovarian cancer.

NLRC3 deficiency promotes cutaneous wound healing due to the inhibition of p53 signaling.

Cutaneous wound healing is a complicated process that is characterized by an initial inflammatory phase followed by a proliferative phase. NLRC3 plays important roles in innate immunity, inflammatory regulation and tumor cell growth. However, the function of NLRC3 in wound healing remains unclear. Here, we investigated the function of NLRC3 in acute cutaneous wound healing using Nlrc3 gene knockout (Nlrc3-/-) mice. Our results demonstrated that skin wound repair in Nlrc3-/- mice was significantly accelerated compared with that in wild-type (WT) mice. NLRC3 deficiency promoted the inflammatory and proliferative phases in wounds enhanced the inflammatory response and increased re-epithelialization and granulation tissue formation, and these phenotypes were primarily ascribed to regulatory effects on p53 signaling. Mechanistically, we uncovered novel crosstalk between NLRC3 and p53 signaling and revealed that NLRC3 could mediate the ubiquitination and degradation of p53 in an Hsp90-dependent manner. In conclusion, our study suggests that NLRC3 is a critical negative regulator of the inflammatory response and cell proliferation during wound healing and that blocking NLRC3 may represent a potential approach for accelerating wound healing.

Study on the Effect of Torrefaction on Pyrolysis Kinetics and Thermal Behavior of Cornstalk Based On a Combined Approach of Chemical and Structural Analyses.

In this study, the effects of torrefaction pretreatment on physicochemical characteristics and pyrolysis behavior of cornstalk were investigated based on the changes in its chemical and structural characteristics. The results indicated that torrefaction treatment improved the fuel properties with elevated torrefaction temperature, including the lower volatile content, higher carbon content, and higher heating value. In addition, serious torrefaction promoted complete degradation of hemicellulose, while the lignin was increased obviously. The crystallinity degree of cornstalk increased first and then reduced with the torrefaction temperature. Slight torrefaction enhanced the devolatilization and thermochemical reactivity of cornstalk, but serious torrefaction discouraged the volatile release. Kinetic parameter analysis indicated that the Ozawa-Flynn-Wall model was more accurate in calculating the activation energy, and the average activation energy gradually increased from 196.06 to 199.21, 203.17, and 217.58 kJ/mol. Furthermore, the thermodynamic parameters also showed an increasing trend with elevated torrefaction temperature. These results provide important basic data support for the thermochemical conversion of cornstalk to energy and chemicals.

Epigenetic induction of lipocalin 2 expression drives acquired resistance to 5-fluorouracil in colorectal cancer through integrin ß3/SRC pathway.

The therapeutic efficacy of 5-fluorouracil (5-FU) is often reduced by the development of drug resistance. We observed significant upregulation of lipocalin 2 (LCN2) expression in a newly established 5-FU-resistant colorectal cancer (CRC) cell line. In this study, we demonstrated that 5-FU-treated CRC cells developed resistance through LCN2 upregulation caused by LCN2 promoter demethylation and that feedback between LCN2 and NF-κB further amplified LCN2 expression. High LCN2 expression was associated with poor prognosis in CRC patients. LCN2 attenuated the cytotoxicity of 5-FU by activating the SRC/AKT/ERK-mediated antiapoptotic program. Mechanistically, the LCN2-integrin ß3 interaction enhanced integrin ß3 stability, thus recruiting SRC to the cytomembrane for autoactivation, leading to downstream AKT/ERK cascade activation. Targeting LCN2 or SRC compromised the growth of CRC cells with LCN2-induced 5-FU resistance. Our findings demonstrate a novel mechanism of acquired resistance to 5-FU, suggesting that LCN2 can be used as a biomarker and/or therapeutic target for advanced CRC.

AFP promotes HCC progression by suppressing the HuR-mediated Fas/FADD apoptotic pathway.

Hepatocellular carcinoma (HCC) is a major leading cause of cancer-related death worldwide. Alpha fetoprotein (AFP) is reactivated in a majority of hepatocellular carcinoma (HCC) and associated with poor patient outcomes. Although increasing evidence has shown that AFP can regulate HCC cell growth, the precise functions of AFP in hepatocarcinogenesis and the associated underlying mechanism remain incompletely understood. In this study, we demostrated that depleting AFP significantly suppressed diethylnitrosamine (DEN)-induced liver tumor progression in an AFP gene-deficient mouse model. Similarly, knocking down AFP expression inhibited human HCC cell proliferation and tumor growth by inducing apoptosis. AFP expression level was inversely associated with the apoptotic rate in mouse and human HCC specimens. Investigation of potential cross-talk between AFP and apoptotic signaling revealed that AFP exerted its growth-promoting effect by suppressing the Fas/FADD-mediated extrinsic apoptotic pathway. Mechanistically, AFP bound to the RNA-binding protein HuR, increasing the accumulation of HuR in the cytoplasm and subsequent inhibition of Fas mRNA translation. In addition, we found that inhibiting AFP enhanced the cytotoxicity of therapeutics to AFP-positive HCC cells by activating HuR-mediated Fas/FADD apoptotic signaling. Conclusion: Our study defined the pro-oncogenic role of AFP in HCC progression and uncovered a novel antiapoptotic mechanism connecting AFP to HuR-mediated Fas translation. Our findings suggest that AFP is involved in the pathogenesis and chemosensitivity of HCC and that blockade of AFP may be a promising strategy to treat advanced HCC.

Synergy of Hydrothermal and Organic Acid Washing Treatments in Chinese Fir Wood Vinegar Preparation.

Pretreatment is an effective method to change the pyrolysis behavior and improve the product properties of biomass. In this study, the effects of hydrothermal treatment (HTT) and hydrothermal treatment combined with organic acid washing (HTT-A) on Chinese fir waste (CF) pyrolysis and preparation of wood vinegar (WV) were investigated. The results indicated that HTT promoted the decomposition of hemicellulose and disrupted the chemical structure, while HTT-A partly removed the lignin as well as hemicellulose. HTT-A showed a more effective removal efficiency of alkali/alkaline earth metals (AAEMs) than HTT. Both HTT and HTT-A delayed the initial decomposition temperature but promoted the pyrolysis process. The yields of WVs increased after HTT and HTT-A, while the moisture contents reduced, obviously. HTT increased the relative contents of phenols from 47.04 to 59.85% but reduced the relative contents of acids from 24.31 to 18.38%, whereas HHT-A reduced the relative contents of phenols but increased those of aldehydes. In addition, HTT and HTT-A showed the different effects on chemical compositions of WVs, especially for phenolic and acid compounds. This study indicated that HTT and HTT-A were the efficient methods to produce WVs with target chemical components, which would be conducive to the efficient application of WVs.

Magnetic bio-activated carbon production from lignin via a streamlined process and its use in phosphate removal from aqueous solutions.

Lignin and ferrous salt were mechanically mixed, melted, carbonized and steam activated to produce magnetic bio-activated carbons (MBACs). Phosphate adsorption capacity measurement was conducted on representative MBAC, which has a high surface iron oxide proportion and mesoporous volume. The results indicate that iron species are embedded into the carbon matrix by lignin melting. Steam is not only an activation agent for pore generation and widening but is also effective for the oxidization of Hagg iron carbide produced via ferrous salt decomposition and subsequent reduction during the carbonization process to form magnetite. The porous and magnetic properties and surface iron oxide content of the produced MBACs can be modified by controlling the steam/magnetic biochar (MBC) ratio. The MBAC production process is streamlined and novel, compared with conventional coprecipitation or impregnation methods. The maximum phosphate adsorption onto the representative MBAC product using the best fitting model, i.e., the Langmuir-Freundlich model, is estimated to be 21.18 mg/g, suggesting that the representative MBAC product has a comparable phosphate adsorption capacity to most of the reported MBCs and MBACs.

Effect of Pyrolysis Temperature on the Characteristics of Wood Vinegar Derived from Chinese Fir Waste: A Comprehensive Study on Its Growth Regulation Performance and Mechanism.

As a high value-added product from biomass pyrolysis, wood vinegar (WV) has been used as a growth regulator for many plant species in agriculture based on the diverse active chemical compounds present. To reveal the relationship between chemical constituents and regulation performance, four kinds of WVs were prepared by slow pyrolysis from Chinese fir waste at different temperature ranges. The chemical constituents of WVs were analyzed by gas chromatography-mass spectrometry, and the regulation performance of WVs was investigated from the aspects of seed germination and root growth of wheat. The results indicated that the chemical constituents of WVs were affected obviously by pyrolysis temperature and the major components were acids and phenols. All types of WVs showed regulation performance but with different effects and levels. The WV collected from 20 to 150 °C exhibited a promoting effect and other three WVs exhibited inhibiting effects. It was considered that the regulation performance of WV was relevant to acids and phenols through a synergy mechanism. Acids caused intercellular acidification and increased root activity, which promoted the seed germination and root growth, while phenols increased the content of malonaldehyde, indicating that phenols caused the oxidative stress to damage cell structure and inhibit growth. All these results could be a reference for further utilization of WVs as a sustainable alternative to chemicals for plant growth regulation in agriculture.

Non-invasive Bioluminescence Monitoring of Hepatocellular Carcinoma Therapy in an HCR Mouse Model.

Animal models play crucial roles in the development of anticancer therapeutics. The ability to quickly assess the localized primary hepatocellular carcinoma (HCC) status in a non-invasive manner would significantly improve the effectiveness of anti-HCC therapeutic studies. However, to date, animal models with this advantage are extremely scarce. In this study, we developed a novel animal model for the fast assessment of drug efficacy against primary HCC in vivo. HCC was induced in immunocompetent hepatocarcinogenesis reporter (HCR) mice by diethylnitrosamine (DEN) injection and confirmed by histopathological staining. Using the bioluminescence imaging (BLI) technique, HCC progression was longitudinally visualized and monitored in a non-invasive way. Tests of two clinical drugs showed that both sorafenib and oxaliplatin significantly inhibited the BLI signal in mouse liver in a dose-dependent manner. The in vivo intensity of BLI signals was highly consistent with the final tumor burden status in mouse liver after drug treatment. The inhibitory effect of anti-HCC drugs was accurately evaluated through in vivo BLI intensity detection. Our study successfully established a bioluminescence mouse model for non-invasive real-time monitoring of HCC therapy, and this HCR mouse model would be a useful tool for potential anti-HCC drug screening and new therapeutic strategy development.

RSPO2 suppresses colorectal cancer metastasis by counteracting the Wnt5a/Fzd7-driven noncanonical Wnt pathway.

R-spondins play critical roles in development, stem cell survival, and tumorigenicity by modulating Wnt/ß-catenin signaling; however, the role of R-spondins in noncanonical Wnt signaling regulation remains largely unknown. We demonstrate here that R-spondin 2 (RSPO2) has an inhibitory effect on colorectal cancer (CRC) cell migration, invasion, and metastasis. Reduced RSPO2 expression was associated with tumor metastasis and poor survival in CRC patients. The metastasis-suppressive activity of RSPO2 was independent of the Wnt/ß-catenin signaling pathway but dependent on the Fzd7-mediated noncanonical Wnt signaling pathway. The physical interaction of RSPO2 and Fzd7 increased the degradation of cell surface Fzd7 via ZNRF3-mediated ubiquitination, which led to the suppression of the downstream PKC/ERK signaling cascade. In late-stage metastatic cancer, Wnt5a promoted CRC cell migration by preventing degradation of Fzd7, and RSPO2 antagonized Wnt5a-driven noncanonical Wnt signaling activation and tumor cell migration by blocking the binding of Wnt5a to the Fzd7 receptor. Our study reveals a novel RSPO2/Wnt5a-competing noncanonical Wnt signaling mechanism that regulates cellular migration and invasion, and our data suggest that secreted RSPO2 protein could serve as a potential therapy for Wnt5a/Fzd7-driven aggressive CRC tumors.

The depletion of ATM inhibits colon cancer proliferation and migration via B56γ2-mediated Chk1/p53/CD44 cascades.

Ataxia-telangiectasia mutated (ATM) protein kinase is a major guardian of genomic stability, and its well-established function in cancer is tumor suppression. Here, we report an oncogenic role of ATM. Using two isogenic sets of human colon cancer cell lines that differed only in their ATM status, we demonstrated that ATM deficiency significantly inhibits cancer cell proliferation, migration, and invasion. The tumor-suppressive function of ATM depletion is not modulated by the compensatory activation of ATR, but it is associated with B56γ2-mediated Chk1/p53/CD44 signaling pathways. Under normal growth conditions, the depletion of ATM prevents B56γ2 ubiquitination and degradation, which activates PP2A-mediated Chk1/p53/p21 signaling pathways, leading to senescence and cell cycle arrest. CD44 was validated as a novel ATM target based on its ability to rescue cell migration and invasion defects in ATM-depleted cells. The activation of p53 induced by ATM depletion suppresses CD44 transcription, thus resulting in epithelial-mesenchymal transition (EMT) and cell migration suppression. Our study suggests that ATM has tumorigenic potential in post-formed colon neoplasia, and it supports ATM as an appealing target for improving cancer therapy.

Recql5 protects against lipopolysaccharide/D-galactosamine-induced liver injury in mice.

AIM: To investigate the effects of Recql5 deficiency on liver injury induced by lipopolysaccharide/D-galactosamine (LPS/D-Gal). METHODS: Liver injury was induced in wild type (WT) or Recql5-deficient mice using LPS/D-Gal, and assessed by histological, serum transaminases, and mortality analyses. Hepatocellular apoptosis was quantified by transferase dUTP nick end labeling assay and Western blot analysis of cleaved caspase-3. Liver inflammatory chemokine and cytochrome P450 expression was analyzed by quantitative reverse transcription-PCR. Neutrophil infiltration was evaluated by myeloperoxidase activity. Expression and phosphorylation of ERK, JNK, p65, and H2A.X was determined by Western blot. Oxidative stress was evaluated by measuring malondialdehyde production and nitric oxide synthase, superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase activity. RESULTS: Following LPS/D-Gal exposure, Recql5-deficient mice exhibited enhanced liver injury, as evidenced by more severe hepatic hemorrhage, higher serum aspartate transaminase and alanine transaminase levels, and lower survival rate. As compared to WT mice, Recql5-deficient mice showed an increased number of apoptotic hepatocytes and higher cleaved caspase-3 levels. Recql5-deficient mice exhibited increased DNA damage, as evidenced by increased γ-H2A.X levels. Inflammatory cytokine levels, neutrophil infiltration, and ERK phosphorylation were also significantly increased in the knockout mice. Additionally, Recql5-deficient mice exhibited increased malondialdehyde production and elevated inducible nitric oxide synthase, superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase activity, indicative of enhanced oxidative stress. Moreover, CYP450 expression was significantly downregulated in Recql5-deficient mice after LPS/D-Gal treatment. CONCLUSION: Recql5 protects the liver against LPS/D-Gal-induced injury through suppression of hepatocyte apoptosis and oxidative stress and modulation of CYP450 expression.

Recruitment of phosphatase PP2A by RACK1 adaptor protein deactivates transcription factor IRF3 and limits type I interferon signaling.

The transcription factor IRF3 is a central regulator of type I interferon (IFN) signaling. The mechanisms underlying deactivation of IRF3 are poorly understood although many studies suggest that IRF3 activity is terminated through degradation after viral infection. Here we report that IRF3 is deactivated via dephosphorylation mediated by the serine and threonine phosphatase PP2A and its adaptor protein RACK1. The PP2A-RACK1 complex negatively regulated the IRF3 pathway after LPS or poly(I:C) stimulation or Sendai virus (SeV) infection. After challenge with LPS, poly(I:C), or low-titer SeV, activated IRF3 was dephosphorylated and returned to resting state without being degraded, although high-titer SeV infection triggered the degradation of IRF3. Furthermore, PP2A-deficient macrophages showed enhanced type I IFN signaling upon LPS, poly(I:C), and SeV challenge and protected mice from lethal vesicular stomatitis virus infection. Therefore, dephosphorylation of IRF3 is a deactivation mechanism that contributes to termination of IRF3-type I IFN signaling.

RSPO2-LGR5 signaling has tumour-suppressive activity in colorectal cancer.

R-spondins are a family of secreted Wnt agonists. One of the family members, R-spondin 2 (RSPO2), has an important role in embryonic development, bone formation and myogenic differentiation; however, its role in human cancers remains largely unknown. Here we show that RSPO2 expression is downregulated in human colorectal cancers (CRCs) due to promoter hypermethylation, and that the RSPO2 reduction correlates with tumour differentiation, size and metastasis. Overexpression of RSPO2 suppresses CRC cell proliferation and tumorigenicity, whereas the depletion of RSPO2 enhances tumour cell growth. RSPO2 has an inhibitory effect on Wnt/ß-catenin signaling in the CRC cells that show suppressed cell proliferation. In human CRC cells, the RSPO2-induced inhibition of Wnt signaling depends on leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5); RSPO2 interacts with LGR5 to stabilize the membrane-associated zinc and ring finger 3 (ZNRF3). Our data suggest that RSPO2 functions as a tumour suppressor in human CRCs, and these data reveal a RSPO2-induced, LGR5-dependent Wnt signaling-negative feedback loop that exerts a net growth-suppressive effect on CRC cells.

Influence of the pore structure and surface chemical properties of activated carbon on the adsorption of mercury from aqueous solutions.

Reactivation and chemical modification were used to obtain modified activated carbons with different pore structure and surface chemical properties. The samples were characterized by nitrogen absorption-desorption, Fourier transform infrared spectroscopy and the Bothem method. Using mercury chloride as the target pollutant, the Hg(2+) adsorption ability of samples was investigated. The results show that the Hg(2+) adsorption capacity of samples increased significantly with increases in micropores and acidic functional groups and that the adsorption process was exothermic. Different models and thermodynamic parameters were evaluated to establish the mechanisms. It was concluded that the adsorption occurred through a monolayer mechanism by a two-speed process involving both rapid adsorption and slow adsorption. The adsorption rate was determined by chemical reaction.