Glycosaminoglycans (GAG) are long, linear polysaccharides that display a wide range of relevant biological roles. Particularly, in the extracellular matrix (ECM) GAG specifically interact with other biological molecules, such as growth factors, protecting them from proteolysis or inhibiting factors. Additionally, ECM GAG are partially responsible for the mechanical stability of tissues due to their capacity to retain high amounts of water, enabling hydration of the ECM and rendering it resistant to compressive forces. In this review, the use of GAG for developing hydrogel networks with improved biological activity and/or mechanical properties is discussed. Greater focus is given to strategies involving the production of hydrogels that are composed of GAG alone or in combination with other materials. Additionally, approaches used to introduce GAG-inspired features in biomaterials of different sources will also be presented.

Biopolymers derived from polysaccharides are a sustainable and environmentally friendly alternative to the synthetic counterparts available in the market. Due to their distinctive properties, the cyanobacterial extracellular polymeric substances (EPS), mainly composed of heteropolysaccharides, emerge as a valid alternative to address several biotechnological and biomedical challenges. Nevertheless, biotechnological/biomedical applications based on cyanobacterial EPS have only recently started to emerge. For the successful exploitation of cyanobacterial EPS, it is important to strategically design the polymers, either by genetic engineering of the producing strains or by chemical modification of the polymers. This requires a better understanding of the EPS biosynthetic pathways and their relationship with central metabolism, as well as to exploit the available polymer functionalization chemistries. Considering all this, we provide an overview of the characteristics and biological activities of cyanobacterial EPS, discuss the challenges and opportunities to improve the amount and/or characteristics of the polymers, and report the most relevant advances on the use of cyanobacterial EPS as scaffolds, coatings, and vehicles for drug delivery.

Autoimmune diseases are life-threatening disorders that cause increasing disability over time. Systemic lupus erythematosus (SLE) and other autoimmune diseases arise when immune stimuli override mechanisms of self-tolerance. Accumulating evidence has demonstrated that protein glycosylation is substantially altered in autoimmune disease development, but the mechanisms by which glycans trigger these autoreactive immune responses are still largely unclear. In this study, we found that presence of microbial-associated mannose structures at the surface of the kidney triggers the recognition of DC-SIGN–expressing γδ T cells, inducing a pathogenic interleukin-17a (IL-17a)–mediated autoimmune response. Mice lacking Mgat5 , which have a higher abundance of mannose structures in the kidney, displayed increased γδ T cell infiltration into the kidney that was associated with spontaneous development of lupus in older mice. N -acetylglucosamine supplementation, which promoted biosynthesis of tolerogenic branched N-glycans in the kidney, was found to inhibit γδ T cell infiltration and control disease development. Together, this work reveals a mannose–γδ T cell–IL-17a axis in SLE immunopathogenesis and highlights glycometabolic reprogramming as a therapeutic strategy for autoimmune disease treatment.

Three new silica-based glass formulations with low molar Ca/P ratio (2–3) have been synthesized. The thermal properties, the crystalline phases induced by thermal treatments and the sintering ability of each glass formulation have been investigated by simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TG), X-ray diffraction (XRD) and hot stage microscopy (HSM). The glasses exhibited a good sintering behavior, with two samples achieving shrinkage of 85%–95% prior to crystallization. The bioactivity of the glasses in simulated body fluid (SBF) has been investigated by performing XRD and Fourier transform infrared spectroscopy (FTIR) on the samples prior and after immersion. The glasses with lower MgO contents were able to form a fully crystallized apatite layer after three days of immersion in simulated body fluid (SBF), while for the glass exhibiting a higher MgO content in its composition, the crystallization of the Ca–P layer was achieved after seven days. The conjugation of these properties opens new insights on the synthesis of highly bioactive and mechanically strong prosthetic materials.