Investigating the Role of the Catalyst within Resorcinol-Formaldehyde Gel Synthesis.

Resorcinol-formaldehyde (RF) gels are porous materials synthesized via a sol-gel reaction and subsequently dried, producing structures with high surface areas and low densities-properties that are highly attractive for use in various applications. The RF gel reaction takes place in the presence of a catalyst, either acidic or basic in nature, the concentration of which significantly impacts final gel properties. The full extent of the catalyst's role, however, has been subject to debate, with the general consensus within the field being that it is simply a pH-adjuster. The work presented here explores this theory, in addition to other theories postulated in the literature, through the synthesis and analysis of RF gels catalysed by mixtures of relevant compounds with varying concentrations. The relationship between catalyst concentration and initial solution pH is decoupled, and the individual roles of both the cation and the anion within the catalyst are investigated. The results presented here point towards the significance of the metal cation within the RF gel reaction, with similar structural properties observed for gels synthesized at constant Na+ concentrations, regardless of the initial solution pH. Furthermore, through the use of alternative cations and anions within catalyst compounds, the potential effects of ions on the stabilization of macromolecules in solution are explored, the results of which suggest a 'Hofmeister-like' series could be applicable within the catalysis of RF gel reactions.

SHP2 Potentiates the Oncogenic Activity of ß-Catenin to Promote Triple-Negative Breast Cancer.

Previous studies have reported dysregulated cytoplasmic and nuclear expression of the ß-catenin protein in triple-negative breast cancer (TNBC) in the absence of Wnt signaling pathway dysregulation. However, the mechanism that sustains ß-catenin protein dysregulation independent of Wnt signaling is not understood. In this study, we show that Src homology phosphotyrosyl phosphatase 2 (SHP2) is essential for ß-catenin protein stability and for sustaining the cytoplasmic and nuclear pools in TNBC cells. The first evidence for this possibility came from immunofluorescence (IF) and immunoblotting (IB) studies that showed that inhibition of SHP2 induces E-cadherin expression and depletion of cytoplasmic and nuclear ß-catenin, which in turn confers adherence junction mediated cell-cell adhesion. We further show that SHP2 promotes ß-catenin protein stability by mediating the inactivation of GSK3ß through its positive effect on Akt and ERK1/2 activation, which was confirmed by direct pharmacologic inhibition of the PI3K-Akt and the MEK-ERK signaling pathway. Finally, we show that SHP2-stabilized ß-catenin contributes to TNBC cell growth, transformation, cancer stem cell (CSC) properties, and tumorigenesis and metastasis. Overall, the findings in this report show that SHP2 mediates ß-catenin protein stability to promote TNBC. IMPLICATIONS: Data presented in this article demonstrates that SHP2 positively regulates ß-catenin protein stability, which in turn promotes triple-negative breast cancer (TNBC) cell transformation, tumorigenesis, and metastasis.

Advancing Computational Analysis of Porous Materials-Modeling Three-Dimensional Gas Adsorption in Organic Gels.

Assessing the efficacy of specific porous materials for use in various applications has been a central focus for many experimental studies over the years, with a view to altering the material properties according to the desired characteristics. The application potential for one such class of nanoporous materials-organic resorcinol-formaldehyde (RF) gels-is of particular interest, due to their attractive and adjustable properties. In this work, we simulate adsorption analysis using lattice-based mean field theory, both in individual pores and within three-dimensional porous materials generated from a kinetic Monte Carlo cluster aggregation model. We investigate the impacts of varying pore size and geometry on the adsorptive behavior, with results agreeing with those previously postulated in the literature. The adsorption analysis is carried out for porous materials simulated with varying catalyst concentrations and solids contents, allowing their structural properties to be assessed from resulting isotherms and the adsorption and desorption processes visualized using density color maps. Isotherm analysis indicated that both low catalyst concentrations and low solids contents resulted in structures with open transport pores that were larger in width, while high catalyst concentrations and solids contents resulted in structures with bottleneck pores that were narrower. We present results from both the simulated isotherms and pore size analysis distributions, in addition to results from RF gels synthesized in the lab and analyzed experimentally, with significant similarities observed between the two. Not only do the results of this comparison validate the kinetic Monte Carlo model's ability to successfully capture the formation of RF gels under varying synthesis parameters, but they also show significant promise for the tailoring of material properties in an efficient and computationally inexpensive manner-something which would be pivotal in realizing their full application potential, and could be applied to other porous materials whose formation mechanism operates under similar principles.

Adsorption and Conformation Behavior of Lysozyme on a Gold Surface Determined by QCM-D, MP-SPR, and FTIR.

The physicochemical properties of protein layers at the solid-liquid interface are essential in many biological processes. This study aimed to link the structural analysis of adsorbed lysozyme at the water/gold surface at pH 7.5 in a wide range of concentrations. Particular attention was paid to the protein's structural stability and the hydration of the protein layers formed at the interface. Complementary methods such as multi-parameter surface plasmon resonance (MP-SPR), quartz crystal microbalance with energy dissipation (QCM-D), and infrared spectroscopy (FTIR) were used for this purpose. The MP-SPR and QCM-D studies showed that, during the formation of a monolayer on the gold surface, the molecules' orientation changes from side-on to end-on. In addition, bilayer formation is observed when adsorbing in the high-volume concentration range >500 ppm. The degree of hydration of the monolayer and bilayer varies depending on the degree of surface coverage. The hydration of the system decreases with filling the layer in both the monolayer and the bilayer. Hydration for the monolayer varies in the range of 50-70%, because the bilayer is much higher than 80%. The degree of hydration of the adsorption layer has a crucial influence on the protein layers' viscoelastic properties. In general, an increase in the filling of a layer is characterized by a rise in its rigidity. The use of infrared spectroscopy allowed us to determine the changes taking place in the secondary structure of lysozyme due to its interaction with the gold surface. Upon adsorption, the content of II-structures corresponding to ß-turn and random lysozyme structures increases, with a simultaneous decrease in the content of the ß-sheet. The increase in the range of ß-turn in the structure determines the lysozyme structure's stability and prevents its aggregation.

Active Hexose-Correlated Compound Restores Gene Expression and Protein Secretion of Protective Cytokines of Immune Cells in a Murine Stress Model during Chlamydia muridarum Genital Infection.

Chlamydia trachomatis genital infection is the most common bacterial sexually transmitted disease worldwide. Previously, we reported that cold-induced stress results in immune suppression of mice that subsequently leads to increased intensity of Chlamydia muridarum genital infection. Furthermore, we demonstrated that stressed mice orally fed with active hexose-correlated compound (AHCC) have reduced shedding of C. muridarum from the genital tract. However, the mechanism of AHCC in reducing the organ load and changing the immune response in the stress model is not well known. This study evaluated infection and changes in immunological parameters of stressed AHCC-fed mice with or without C. muridarum genital infection. We hypothesized that AHCC feeding to stressed mice restores protective immune function and reduces susceptibility to C. muridarum genital infection. The results show that oral feeding of stressed mice with AHCC resulted in decreased shedding of C. muridarum from the genital tract, reduced production of plasma catecholamines, increased expression of T-bet and reduced GATA-3 in CD4+ T cells, increased production of interleukin-12 (IL-12) and interferon gamma (IFN-γ) and reduced production of IL-4 in CD4+ T cells, and enhanced expression of surface markers and costimulatory molecules of CD4+ T cells, bone marrow-derived dendritic cells (BMDCs), and natural killer cells. Coculturing of mature BMDCs with splenic CD4+ T cells led to the increased and decreased production of T helper 1 and T helper 2 cytokines, respectively. Overall, our results show that AHCC fosters the restoration of Th1 cytokine production while reducing Th2 cytokine production, which would promote C. muridarum clearance in the murine stress model.

Modelling Organic Gel Growth in Three Dimensions: Textural and Fractal Properties of Resorcinol-Formaldehyde Gels.

Tailoring the properties of porous organic materials, such as resorcinol-formaldehyde gels, for use in various applications has been a central focus for many studies in recent years. In order to achieve effective optimisation for each application, this work aims to assess the impact of the various synthesis parameters on the final textural properties of the gel. Here, the formation of porous organic gels is modelled using a three-dimensional lattice-based Monte Carlo simulation. We model growth from monomer species into the interconnected primary clusters of a gel, and account for varying catalyst concentration and solids content, two parameters proven to control gel properties in experimental work. In addition to analysing the textural properties of the simulated materials, we also explore their fractal properties through correlation dimension and Hurst exponent calculations. The correlation dimension shows that while fractal properties are not typically observed in scattering experiments, they are possible to achieve with sufficiently low solids content and catalyst concentration. Furthermore, fractal properties are also apparent from the analysis of the diffusion path of guest species through the gel's porous network. This model, therefore, provides insight into how porous organic gels can be manufactured with their textural and fractal properties computationally tailored according to the intended application.

Modulation of T helper 1 and T helper 2 immune balance in a murine stress model during Chlamydia muridarum genital infection.

A murine model to study the effect of cold-induced stress (CIS) on Chlamydia muridarum genital infection and immune response has been developed in our laboratory. Previous results in the lab show that CIS increases the intensity of chlamydia genital infection, but little is known about the effects and mechanisms of CIS on the differentiation and activities of CD4+ T cell subpopulations and bone marrow-derived dendritic cells (BMDCs). The factors that regulate the production of T helper 1 (Th1) or T helper 2 (Th2) cytokines are not well defined. In this study, we examined whether CIS modulates the expressions of beta-adrenergic receptor (ß-AR), transcription factors, hallmark cytokines of Th1 and Th2, and differentiation of BMDCs during C. muridarum genital infection in the murine model. Our results show that the mRNA level of the beta2-adrenergic receptor (ß2-AR) compared to ß1-AR and ß3-AR was high in the mixed populations of CD4+ T cells and BMDCs. Furthermore, we observed decreased expression of T-bet, low level of Interferon-gamma (IFN-γ) production, increased expression of GATA-3, and Interleukin-4 (IL-4) production in CD4+ T cells of stressed mice. Exposure of BMDCs to Fenoterol, ß2-AR agonist, or ICI118,551, ß2-AR antagonist, revealed significant ß2-AR stimulation or inhibition, respectively, in stressed mice. Moreover, co-culturing of mature BMDCs and naïve CD4+ T cells increased the production of IL-4, IL-10, L-17, and IL-23 cytokines, suggesting that stimulation of ß2-AR leads to the increased production of Th2 cytokines. Overall, our results show for the first time that CIS promotes the switching from a Th1 to Th2 cytokine environment. This was evidenced in the murine stress model by the overexpression of GATA-3 concurrent with elevated IL-4 production, reduced T-bet expression, and IFN-γ secretion.

Conditional knockout of SHP2 in ErbB2 transgenic mice or inhibition in HER2-amplified breast cancer cell lines blocks oncogene expression and tumorigenesis.

Overexpression of the human epidermal growth factor receptor 2 (HER2) is the cause of HER2-positive breast cancer (BC). Although HER2-inactivating therapies have benefited BC patients, development of resistance and disease recurrence have been the major clinical problems, pointing to a need for alternative therapeutic strategies. For that to happen, proteins that play critical roles in the biology of HER2-induced tumorigenesis have to be identified and characterized. Here, we show that the Src homology phosphotyrosyl phosphatase 2 (Shp2) encoded by the Ptpn11 gene is a requisite for ErbB2-induced tumorigenesis. We report that conditional knockout of Shp2 alleles in the ErbB2 BC model mice abrogates mammary tumorigenesis by blocking the expression of the ErbB2 transgene. We also show that inhibition of SHP2 encoded by the PTPN11 gene in the HER2-amplified BC cells induces a normal-like cellular phenotype and suppresses tumorigenesis and metastasis by blocking HER2 overexpression. These findings demonstrate that ErbB2-induced tumors in mice or xenograft tumors induced by transplantation of HER2-amplified BC cells are vulnerable to SHP2 inhibition since it abrogates the expression of the very oncogene that causes of the disease. This report paves the way for developing SHP2-targeting therapies for BC treatment in the future.

SHP2 acts both upstream and downstream of multiple receptor tyrosine kinases to promote basal-like and triple-negative breast cancer.

INTRODUCTION: Dysregulated receptor tyrosine kinase (RTK) signaling is a common occurrence in basal-like and triple-negative breast cancer (BTBC). As a result, RTK-targeting therapies have been initiated but proved difficult, mainly owing to the multiplicity of dysregulated RTKs. Hence, targeting master regulators of RTK signaling might alleviate this obstacle. Before that, however, defining the mechanism of such molecules is required. In this report, we show that the Src homology phosphotyrosyl phosphatase 2 (SHP2) is a master regulator of RTK expression and signaling in BTBC. METHODS: Xenograft tumor growth studies were used to determine the effect of SHP2 inhibition on tumorigenesis and/or metastasis. Cell proliferation rate, anchorage-independent growth, mammosphere formation, and ALDEFLUOR assays were used to compare the relative functional importance of SHP2 and the epidermal growth factor receptor (EGFR) in BTBC cells. Immunohistochemistry and immunofluorescence analyses were used to determine the state of SHP2 and EGFR coexpression in BTBC. Analysis of mitogenic and cell survival signaling was performed to show SHP2's role in signaling by multiple RTKs. RESULTS: Inhibition of SHP2 in BTBC cells suppresses their tumorigenic and metastatic properties. Because EGFR is the most commonly dysregulated RTK in BTBC, we first tested the effect of SHP2 inhibition on EGFR signaling and found that SHP2 is important not only for mediation of the Ras/extracellular signal-regulated kinase and the phosphatidyl inositol 3-kinase/Akt signaling pathways but also for the expression of the receptor itself. The existence of a tight association between SHP2 and EGFR expression in tumors and cell lines further suggested the importance of SHP2 in EGFR expression. Comparison of relative biological significance showed the superiority of SHP2 inhibition over that of EGFR, suggesting the existence of additional RTKs regulated by SHP2. Indeed, we found that the expression as well as the signaling efficiency of c-Met and fibroblast growth factor receptor 1, two other RTKs known to be dysregulated in BTBC, are SHP2-dependent. To our knowledge, this is the first demonstration of SHP2 acting both upstream and downstream of RTKs to promote signaling. CONCLUSIONS: SHP2 upregulates the expression and signaling of multiple RTKs to promote BTBC. These findings provide a mechanistic explanation for the superiority of SHP2 inhibition in BTBC.