Selective Integrin αβ Targeting through Spatially Constrained Multivalent DNA-Based Nanoparticles.

Targeting cells specifically based on receptor expression levels remains an area of active research to date. Selective binding of receptors cannot be achieved by increasing the individual binding strength, as this does not account for differing distributions of receptor density across healthy and diseased cells. Engaging receptors above a threshold concentration would be desirable in devising selective diagnostics.

Strategic Insights into Engineering Parameters Affecting Cell Type-Specific Uptake of DNA-Based Nanomaterials.

DNA-based nanomaterials are gaining popularity as uniform and programmable bioengineering tools as a result of recent solutions to their weak stability under biological conditions. The DNA nanotechnology platform uniquely allows decoupling of engineering parameters to comprehensively study the effect of each upon cellular encounter. We here present a systematic analysis of the effect of surface parameters of DNA-based nanoparticles on uptake in three different cell models: tumor cells, macrophages, and dendritic cells.

Spatially Controlled Activation of Toll-like Receptor 9 with DNA-Based Nanomaterials.

First evidence of geometrical patterns and defined distances of biomolecules as fundamental parameters to regulate receptor binding and cell signaling have emerged recently. Here, we demonstrate the importance of controlled nanospacing of immunostimulatory agents for the activation of immune cells by exploiting DNA-based nanomaterials and pre-existing crystallography data. We created DNA origami nanoparticles that present CpG-motifs in rationally designed spatial patterns to activate Toll-like Receptor 9 in RAW 264.

IL10- and IL35-Secreting MutuDC Lines Act in Cooperation to Inhibit Memory T Cell Activation Through LAG-3 Expression.

Dendritic cells (DCs) are professional antigen-presenting cells involved in the initiation of immune responses. We generated a tolerogenic DC (tolDC) line that constitutively secretes interleukin-10 (IL10-DCs), expressed lower levels of co-stimulatory and MHCII molecules upon stimulation, and induced antigen-specific proliferation of T cells. Vaccination with IL10-DCs combined with another tolDC line that secretes IL-35, reduced antigen-specific local inflammation in a delayed-type hypersensitivity assay independently on regulatory T cell differentiation.

Leukotriene B modulation of murine dendritic cells affects adaptive immunity.

Dendritic cells (DCs) link innate and adaptive immunity. The microenvironment generated during the innate immunity affects DCs and the type of adaptive immunity generated. Lipid mediators are released early in inflammation and could modify the functional state of DCs.

Importance of EMT Factor ZEB1 in cDC1 "MutuDC Line" Mediated Induction of Th1 Immune Response.

The role of Epithelial to Mesenchymal Transition (EMT) factor Zeb1 is well defined in metastasis and cancer progression but it's importance in dendritic cells (DCs) is unexplored until now. For the first time we report here that Zeb1 controls immunogenic responses of CD8α conventional Type-I (cDC1) DCs. We found that ZEB1 expression increases significantly after TLR9 stimulation and its depletion impairs activation, co-stimulation and secretion of important cytokines like IL-6, IL-10 and IL-12 in cDC1 MutuDC line.

Boosting Adaptive Immunity: A New Role for PAFR Antagonists.

We have previously shown that the Platelet-Activating Factor Receptor (PAFR) engagement in murine macrophages and dendritic cells (DCs) promotes a tolerogenic phenotype reversed by PAFR-antagonists treatment in vitro. Here, we investigated whether a PAFR antagonist would modulate the immune response in vivo. Mice were subcutaneously injected with OVA or OVA with PAFR-antagonist WEB2170 on days 0 and 7.

PAFR in adipose tissue macrophages is associated with anti-inflammatory phenotype and metabolic homoeostasis.

Metabolic dysfunction is associated with adipose tissue inflammation and macrophage infiltration. PAFR (platelet-activating factor receptor) is expressed in several cell types and binds to PAF (platelet-activating factor) and oxidized phospholipids. Engagement of PAFR in macrophages drives them towards the anti-inflammatory phenotype.

Uptake of oxLDL and IL-10 production by macrophages requires PAFR and CD36 recruitment into the same lipid rafts.

Macrophage interaction with oxidized low-density lipoprotein (oxLDL) leads to its differentiation into foam cells and cytokine production, contributing to atherosclerosis development. In a previous study, we showed that CD36 and the receptor for platelet-activating factor (PAFR) are required for oxLDL to activate gene transcription for cytokines and CD36. Here, we investigated the localization and physical interaction of CD36 and PAFR in macrophages stimulated with oxLDL.

Activation of PAF-receptor induces regulatory dendritic cells through PGE2 and IL-10.

Activation of the platelet-activating factor receptor (PAFR) in macrophages is associated with suppressor phenotype. Here, we investigated the PAFR in murine dendritic cells (DC). Bone marrow-derived dendritic cells (BALB/c) were cultured with GM-CSF and maturation was induced by LPS.

Oxidized LDL induces alternative macrophage phenotype through activation of CD36 and PAFR.

OxLDL is recognized by macrophage scavenger receptors, including CD36; we have recently found that Platelet-Activating Factor Receptor (PAFR) is also involved. Since PAFR in macrophages is associated with suppressor function, we examined the effect of oxLDL on macrophage phenotype. It was found that the presence of oxLDL during macrophage differentiation induced high mRNA levels to IL-10, mannose receptor, PPAR γ and arginase-1 and low levels of IL-12 and iNOS.

Fibroblast growth factor 2 causes G2/M cell cycle arrest in ras-driven tumor cells through a Src-dependent pathway.

We recently reported that paracrine Fibroblast Growth Factor 2 (FGF2) triggers senescence in Ras-driven Y1 and 3T3(Ras) mouse malignant cell lines. Here, we show that although FGF2 activates mitogenic pathways in these Ras-dependent malignant cells, it can block cell proliferation and cause a G2/M arrest. These cytostatic effects of FGF2 are inhibited by PD173074, an FGF receptor (FGFR) inhibitor.

Fibroblast growth factor 2 restrains Ras-driven proliferation of malignant cells by triggering RhoA-mediated senescence.

Fibroblast growth factor 2 (FGF2) is considered to be a bona fide oncogenic factor, although results from our group and others call this into question. Here, we report that exogenous recombinant FGF2 irreversibly inhibits proliferation by inducing senescence in Ras-dependent malignant mouse cells, but not in immortalized nontumorigenic cell lines. We report the following findings in K-Ras-dependent malignant Y1 adrenocortical cells and H-Ras V12-transformed BALB-3T3 fibroblasts: (a) FGF2 inhibits clonal growth and tumor onset in nude and immunocompetent BALB/c mice, (b) FGF2 irreversibly blocks the cell cycle, and (c) FGF2 induces the senescence-associated beta-galactosidase with no accompanying signs of apoptosis or necrosis.