Critical features of an in vitro intestinal absorption model to study the first key aspects underlying food allergen sensitization

New types of protein sources will enter our diet in a near future, reinforcing the need for a straightforward in vitro (cell-based) screening model to test and predict the safety of these novel proteins, in particular their potential risk for de novo allergic sensitization. The Adverse Outcome Pathway (AOP) for allergen sensitization describes the current knowledge of key events underlying the complex cellular interactions that proceed allergic food sensitization. Currently, there is no consensus on the in vitro model to study the intestinal translocation of proteins as well as the epithelial activation, which comprise the first molecular initiation events (ME1-3) and the first key event of the AOP, respectively. As members of INFOGEST, we have highlighted several critical features that should be considered for any proposed in vitro model to study epithelial protein transport in the context of allergic sensitization. In addition, we defined which intestinal cell types are indispensable in a consensus model of the first steps of the AOP, and which cell types are optional or desired when there is the possibility to create a more complex cell model. A model of these first key aspects of the AOP can be used to study the gut epithelial translocation behavior of known hypo- and hyperallergens, juxtaposed to the transport behavior of novel proteins as a first screen for risk management of dietary proteins. Indeed, this disquisition forms a basis for the development of a future consensus model of the allergic sensitization cascade, comprising also the other key events (KE2-5).     

Detecting the imprints of past clear-cutting on riparian forest plant communities along a Mediterranean river

In riparian forests, clear-cutting causes long-lasting changes in both riparian and aquatic biota. In this work, we examined if past clear-cutting events occurred at different times have imprints on riparian forests in a Mediterranean river in central Italy. We carried out a randomized, plot-based vegetation survey of riparian forests in systematically sampled 500 m-long sectors along the whole river, dividing the riparian zone into two internal and two external strips. From historical aerial photos, past clear-cutting events within plots were detected and classified in age classes: (i) cut in the past 8 years (recent); (ii) cut between 8 and 19 years ago (intermediate); (iii) no signs of clear-cutting in the last 19 years (distant). We analyzed the responses of vegetation to clear-cutting and strip position. Alien species richness was higher and woody species richness was lower in recently clear-cut areas compared to those with a distant clear-cutting event. Moreover, recently cut woods had more alien and synanthropic species. Intermediate clear-cut areas had higher levels of invasion by alien species compared to areas with distant cut. Riparian forests of internal strips are impacted by clear-cutting, but seem to recover in 8–19 years thanks to their natural resilience. Conversely, recent or intermediate clear-cutting events did not affect any of the investigated vegetation attributes in the external strips since such forests were already invaded by alien and synanthropic species after human disturbance. Our results confirm that clear-cutting events can have long-lasting effects on Mediterranean riparian forests, confirming the vulnerability of river ecosystems to clear-cutting and suggesting the need for more caution in management practices to improve the conservation status of riparian forests.     

Conformationally Constrained Sialyl Analogues as New Potential Binders of h-CD22

Here, two conformationally constrained sialyl analogues were synthesized and characterized in their interaction with the inhibitory Siglec, human CD22 (h-CD22). An orthogonal approach, including biophysical assays (SPR and fluorescence), ligand-based NMR techniques, and molecular modelling, was employed to disentangle the interaction mechanisms at a molecular level. The results showed that the Sialyl-TnThr antigen analogue represents a promising scaffold for the design of novel h-CD22 inhibitors. Our findings also suggest that the introduction of a biphenyl moiety at position 9 of the sialic acid hampers canonical accommodation of the ligand in the protein binding pocket, even though the affinity with respect to the natural ligand is increased. Our results address the search for novel modifications of the Neu5Ac-α(2-6)-Gal epitope, outline new insights for the design and synthesis of high-affinity h-CD22 ligands, and offer novel prospects for therapeutic intervention to prevent autoimmune diseases and B-cell malignancies.     

Self-Healing Ability of Poly(PEGMA-5-UPy) Evaluated by Thermomechanical Analysis

The synthesis and characterization of polyethylene glycol monomethyl ether methacrylate (PEGMA) based copolymers incorporating three different percentages (2.5 wt%, 5.0 wt%, and 7.8 wt%) of urea-N-2-amino-4-hydroxy-6-methylpyrimidine-N’-(hexametylen-n-carboxyethyl methacrylate) (HEMA-UPy) are reported. Nuclear magnetic resonance (NMR) and infrared spectroscopy (IR) confirm the synthesis procedure. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are employed to evaluate the thermal properties of the samples. DSC measurements evidence a slight increase in glass transition temperature (T_g), a consistent increase in crystallization and melting temperatures (T_c and T_m), and a reduction in the crystallization degree (X_c) with increasing the amount of HEMA-UPy moiety. Dynamic mechanical analysis (DMA) is carried out at different values of temperature and oscillation frequency. It highlights the ability of the healed copolymer to recover the pristine values of storage modulus. The healing efficiency depends on the temperature history of the sample. For the sample healed at room temperature, the value of healing efficiency is 64%. DMA tests performed at higher temperatures, after some permanence at room temperature, evidence higher values in the healing efficiency. This demonstrates that the higher value of the temperature employed during DMA tests determines greater mobility of the chains causing an enhancement in the healing efficiency.