Glioblastoma is a highly malignant and incurable brain tumor characterized by intrinsic and adaptive resistance to immunotherapies. However, how glioma cells induce tumor immunosuppression and escape immunosurveillance remains poorly understood. Here, we find upregulation of cancer-intrinsic Chitinase-3-like-1 (CHI3L1) signaling modulating an immunosuppressive microenvironment by reprogramming tumor-associated macrophages (TAMs). Mechanistically, CHI3L1 binding with Galectin-3 (Gal3) selectively promotes TAM migration and infiltration with a protumor M2-like but not an antitumor M1-like phenotype in vitro and in vivo, governed by a transcriptional program of NFκB/CEBPβ in the CHI3L1/Gal3-PI3K/AKT/mTOR axis. Conversely, Galectin-3-binding protein (Gal3BP) negatively regulates this process by competing with Gal3 to bind CHI3L1.Administration of a Gal3BP mimetic peptide in syngeneic glioblastoma mouse models reverses immune suppression and attenuates tumor progression. These results shed light on the role of CHI3L1 protein complexes in immune evasion by glioblastoma and as a potential immunotherapeutic target for this devastating disease.

Mediator is a modular multisubunit complex that functions as a critical coregulator of RNA polymerase II (Pol II) transcription. While it is well accepted that Mediator plays important roles in the assembly and function of the preinitiation complex (PIC), less is known of its potential roles in regulating downstream steps of the transcription cycle. Here we use a combination of genetic and molecular approaches to investigate Mediator regulation of Pol II elongation in the model eukaryote, Saccharomyces cerevisiae. We find that ewe (expression without heat shock element) mutations in conserved Mediator subunits Med7, Med14, Med19, and Med21-all located within or adjacent to the middle module-severely diminish heat-shock-induced expression of the Hsf1-regulated HSP82 gene. Interestingly, these mutations do not impede Pol II recruitment to the gene's promoter but instead impair its transit through the coding region. This implies that a normal function of Mediator is to regulate a postinitiation step at HSP82. In addition, displacement of histones from promoter and coding regions, a hallmark of activated heat-shock genes, is significantly impaired in the med14 and med21 mutants. Suggestive of a more general role, ewe mutations confer hypersensitivity to the antielongation drug 6-azauracil (6-AU) and one of them-med21-impairs Pol II processivity on a GAL1-regulated reporter gene. Taken together, our results suggest that yeast Mediator, acting principally through its middle module, can regulate Pol II elongation at both heat-shock and non-heat-shock genes. IN eukaryotes, transcription of the DNA template into premRNA by RNA polymerase II (Pol II) occurs in a welldefined, stepwise fashion. First, chromatin, the nucleoprotein complex in which the DNA is packaged, must unfold into a 10 nm, beads-on-a-string filament, and for many genes a nucleosome-free region needs to be created over the core promoter (Venters and Pugh 2009). Both are achieved via activator-mediated recruitment of chromatin modification and remodeling enzymes (reviewed in Li et al. 2007). Once a permissive chromatin template has been created, Pol II and the other general transcription factors then bind the core promoter, where they are assembled into a preinitiation complex (PIC; formally analogous to the closed RNA polymerase complex in prokaryotes). Next, Pol II forms an open complex concomitant with ATP-dependent melting of the DNA strands and initiates transcription following phosphorylation of its C-terminal repeat domain (CTD) at Ser5 residues by the TFIIH kinase, Cdk7. Following synthesis of 25-30 nucleotides, Pol II pauses, allowing the nascent RNA to be capped. Finally, Pol II transitions to productive elongation, which requires Ser2 phosphorylation of the CTD. In metazoans, this is catalyzed by P-TEFb and in yeast by Bur1 and Ctk1 (reviewed in Saunders et al. 2006).A key regulator of many of the above steps is Mediator, an evolutionarily conserved, modular multiprotein complex. Mediator acts as a signal transducer through its interac...

A multilayer metamaterial with switchable functionalities is presented based on the phase-transition property of vanadium dioxide. When vanadium dioxide is in the metallic state, a broadband absorber is formed. Calculated results show that the combination of two absorption peaks enables absorptance more than 90% in the wide spectral range from 0.393 THz to 0.897 THz. Absorption performance is insensitive to polarization at the small incident angle and work well even at the larger incident angle. When vanadium dioxide is in the insulating state, the designed system behaves as a narrowband absorber at the frequency of 0.677 THz. This narrowband absorber shows the advantages of wide angle and polarization insensitivity due to the localized magnetic resonance. Furthermore, the influences of geometrical parameters on the performance of absorptance are discussed. The proposed switchable absorber can be used in various applications, such as selective heat emitter and solar photovoltaic field.

Single-cell analysis has attracted increasing attention because of cell heterogeneities. Various strategies have been developed for analyzing single cells, but most of these analytical processes kill the cells. Tools that can qualitatively and quantitatively measure the cellular contents without killing the cell are highly demanding because they enable us to conduct single-cell time-course studies (e.g., to examine how a cell responds to a therapy before, during, and after a treatment). Here we develop a femto-liter (fL) pipet to serve this purpose. To ensure that we can accurately and precisely pipet fL solutions, we fill all conduits with liquid and use an electroosmotic pump (EOP) as the driving force to facilitate withdrawal of cellular contents from single cells. We tentatively term this device an EOP-driven pipette or EDP. We characterize the EDP for accurately and precisely withdrawing solution from ∼250 fL to 80 nL; a volume range that covers the applications for most types of cells. To demonstrate the feasibility of utilizing the EDP for a single-cell time-course study, we utilize the EDP to take the cellular contents out at different times during the course of a zebrafish embryo development for cholesterol measurements. More than 50% of the embryos survive after each pipetting and analysis step, and this number will increase considerably as we improve our cell manipulation skills and reduce the pipet-tip diameter. We expect this EDP to become an effective tool for single-cell time-course studies.

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We integrate a high-pressure electroosmotic pump (EOP), a nanoflow gradient generator, and a capillary column into a miniaturized liquid chromatographic system that can be directly coupled with a mass spectrometer for proteomic analysis. We have recently developed a low-cost high-pressure EOP capable of generating pressure of tens of thousands psi, ideal for uses in miniaturized HPLC. The pump worked smoothly when it was used for isocratic elutions. When it was used for gradient elutions, generating reproducible gradient profiles was challenging; because the pump rate fluctuated when the pump was used to pump high-content organic solvents. This presents an issue for separating proteins/peptides since high-content organic solvents are often utilized. In this work, we solve this problem by incorporating our high-pressure EOP with a nano-flow gradient generator so that the EOP needs only to pump an aqueous solution. With this combination, we develop a capillary-based nano-HPLC system capable of performing nano-flow gradient elution; the pump rate is stable, and the gradient profiles are reproducible and can be conveniently tuned. To demonstrate its utility, we couple it with either a UV absorbance detector or a mass spectrometer for peptide separations.

We have experimentally demonstrated the extraordinarily high resolving power of liquid chromatography (LC) using a narrow open tubular (OT) column. In this work, we show that we can further increase its efficiency, peak capacity, and separation speed by elevating the operation (or column) temperature; all of these three numbers can be improved without mutual compromises. We use a mixture of five amino acids as a sample and show that we can increase the efficiency by 34%–260% and the separation speeds by 7%–10% by raising the operation temperature from 30 to 70 °C. When we use a 2 μm i.d. × 80 cm in length OT column coated with OTMS at a temperature of 70 °C, we can frequently obtain peak capacities of 700–800 within 20–30 min for separating cytochrome C digests. By increasing the column length to 160 cm, we can obtain a peak capacity of 2720 within 143 min for separating a complex peptide sample. This peak capacity is the highest peak capacity to date for one-dimensional LC separations. Importantly, heating the column is easy to implement and does not cost much, and many commercial LC systems already have compartments to control column temperatures. Running LC using a narrow OT column at an elevated temperature should broaden the applications of OT-LC in chemical and biochemical analyses.