Regulating the proinflammatory response to composite biomaterials by targeting immunometabolism

Composite biomaterials comprising polylactide(PLA)and hydroxyapatite(HA)are applied in bone,cartilage and dental regenerative medicine,where HA confers osteoconductive properties.However,after surgical implantation,adverse immune responses to these composites can occur,which have been attributed to size and morphology of HA particles.Approaches to effectively modulate these adverse immune responses have not been described.PLA degradation products have been shown to alter immune cell metabolism(immunometabolism),which drives the inflammatory response.Accordingly,to modulate the inflammatory response to composite biomaterials,inhibitors were incorporated into composites comprised of amorphous PLA(aPLA)and HA(aPLA+HA)to regulate glycolytic flux.Inhibition at specific steps in glycolysis reduced proinflammatory(CD86+CD206-)and increased pro-regenerative(CD206+)immune cell populations around implanted aPLA+HA.Notably,neutrophil and dendritic cell(DC)numbers along with proinflammatory monocyte and macrophage populations were decreased,and Arginase 1 expression among DCs was increased.Targeting immunometabolism to control the proinflammatory response to biomaterial composites,thereby creating a pro-regenerative microenvironment,is a significant advance in tissue engineering where immunomodulation enhances osseointegration and angiogenesis,which could lead to improved bone regeneration.

Binding of the SARS-CoV-2 spike protein to glycans

The pandemic of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has caused a high number of deaths in the world.To combat it,it is necessary to develop a better understanding of how the virus infects host cells.Infection normally starts with the attachment of the virus to cell-surface glycans like heparan sulfate(HS)and sialic acid-containing glycolipids/glycoproteins.In this study,we examined and compared the binding of the subunits and spike(S)proteins of SARS-CoV-2,SARS-Co V,and Middle East respiratory disease(MERS)-Co V to these glycans.Our results revealed that the S proteins and subunits can bind to HS in a sulfation-dependent manner and no binding with sialic acid residues was detected.Overall,this work suggests that HS binding may be a general mechanism for the attachment of these coronaviruses to host cells,and supports the potential importance of HS in infection and in the development of antiviral agents against these viruses.

Methods for engineering therapeutic peptides

Peptides are a class of drugs that have become increasingly important and influential for the treatment of many human diseases. Compared to traditional small molecule drugs, peptides have the potential for higher target specificity and potency, along with better safety profiles. On the other hand, the complex and fragile nature of peptides poses significant challenges for their administration. Of particular concern is that they are often unstable and can be rapidly degraded by various proteases after dosing. To address these inherent problems of peptides, many different methods have been attempted. Here, we briefly review these methods, with an emphasis on the effect of each method.