Modeling Glyco-Collagen Conjugates Using a Host-Guest Strategy To Alter Phenotypic Cell Migration and in Vivo Wound Healing

Synergistic wound repair effects of a composite hydrogel for delivering tumor-derived vesicles and S-nitrosoglutathione

Treating chronic wounds requires transition from proinflammatory M1 to anti-inflammatory M2 dominant macrophages. Based on the role of tumor extracellular vesicles (tEVs) in regulating the phenotypic switching from M1 to M2 macrophages, we propose that tEVs may have a beneficial impact on alleviating the overactive inflammatory microenvironment associated with refractory wounds. On the other hand, as a nitric oxide donor, S-nitrosoglutathione (GSNO) can regulate inflammation, promote angiogenesis, enhance matrix deposition, and facilitate wound healing. In this study, a guar gum-based hydrogel with tEVs and GSNO was designed for the treatment of diabetic refractory wounds. This hybrid hydrogel was formed through the phenyl borate bonds, which can automatically disintegrate in response to the high reactive oxygen species (ROS) level at the site of refractory diabetic wounds, releasing tEVs and GSNO. We conducted a comprehensive evaluation of this hydrogel in vitro, which demonstrated excellent performance. Meanwhile, using a full-thickness excision model in diabetic mice, the wounds exposed to the therapeutic hydrogel healed completely within 21 days. The increased closure rate was associated with macrophage polarization and collagen deposition, accelerated fibroblast proliferation, and increased angiogenesis in the regenerating tissues. Therefore, this multifunctional hybrid hydrogel appears to be promising for clinical applications.

Sulfation Code and Conformational Plasticity of l-Iduronic Acid Homo-Oligosaccharides Mimic the Biological Functions of Heparan Sulfate

Recently, the activity of heparan sulfate (HS) has led to the discovery of many drug candidates that have the potential to impact both medical science and human health. However, structural diversity and synthetic challenges impede the progress of HS research. Here, we report a library of novel l-iduronic acid (IdoA)-based HS mimics that are highly tunable in conformation plasticity and sulfation patterns to produce many of the functions of native HS oligosaccharides. The NMR analysis of HS mimics confirmed that 4-O-sulfation enhances the population of the ¹C₄ geometry. Interestingly, the ¹C₄ conformer becomes exclusive upon additional 2-O-sulfation. HS mimic microarray binding studies with different growth factors showed that selectivity and avidity are greatly modulated by the oligosaccharide length, sulfation code, and IdoA conformation. Particularly, we have identified 4-O-sulfated IdoA disaccharide (I-21) as a potential ligand for vascular endothelial growth factor (VEGF₁₆₅), which in a multivalent display modulated endothelial cell proliferation, migration, and angiogenesis. Overall, these results encourage the consideration of HS mimics for therapeutic applications.

Synthetic heparan sulfate ligands for vascular endothelial growth factor to modulate angiogenesis

We report the discovery of a potential heparan sulfate (HS) ligand to target several growth factors using 13 unique HS tetrasaccharide ligands. By employing an HS microarray and SPR, we deciphered the crucial structure-binding relationship of these glycans with the growth factors BMP2, VEGF₁₆₅, HB-EGF, and FGF2. Notably, GlcNHAc(6-O-SO₃^-)-IdoA(2-O-SO₃^-) (HT-2,6S-NAc) tetrasaccharide showed strong binding with the VEGF₁₆₅ growth factor. In vitro vascular endothelial cell proliferation, migration and angiogenesis was inhibited in the presence of VEGF₁₆₅ and HT-2,6S-NAc or HT-6S-NAc, revealing the potential therapeutic role of these synthetic HS ligands.

Heparan Sulfate Mimetics Differentially Affect Homologous Chemokines and Attenuate Cancer Development

Achieving selective inhibition of chemokine activity by structurally well-defined heparan sulfate (HS) or HS mimetic molecules can provide important insights into their roles in individual physiological and pathological cellular processes. Here, we report a novel tailor-made HS mimetic, which furnishes an exclusive iduronic acid (IdoA) scaffold with different sulfation patterns and oligosaccharide chain lengths as potential ligands to target chemokines. Notably, highly sulfated-IdoA tetrasaccharide (I-45) exhibited strong binding to CCL2 chemokine thereby blocking CCL2/CCR2-mediated in vitro cancer cell invasion and metastasis. Taken together, IdoA-based HS mimetics offer an alternative HS substrate to generate selective and efficient inhibitors for chemokines and pave the way to a wide range of new therapeutic applications in cancer biology and immunology.

Adaptive Multifunctional Supramolecular Assemblies of Glycopeptides Rapidly Enable Morphogenesis

Despite the well-established biophysical principle of adhesion-guided in vitro morphogenesis, there are few single synthetic molecular species that can rapidly enable morphogenesis (e.g., a cell monolayer to cell spheroids) in a cell culture because adhesion inherently involves many signals. Here we show the use of adaptive multifunctional supramolecular assemblies of glycopeptides, consisting of cell adhesion sequence and saccharide, to induce cell spheroids rapidly from a monolayer of cells. Having a general architecture of N-terminal capping, glycosylation, and an integrin-binding sequence, the glycopeptides self-assemble to form a dynamic continuum of nanostructures (i.e., from nanoparticles to nanofibers) to affect the interactions of integrins, E-selectin, and cadherins with their natural ligands and to act adaptively according to the cellular environment. Such adaptive (i.e., context-dependent) interactions weaken cell-substratum adhesion and enhance intercellular interactions, which rapidly and transiently induce cell spheroids. This work illustrates the use of supramolecular assemblies of simple glycopeptides to modulate biophysical conditions for regulating cell functions, which is a new approach for developing biomaterials.