Insulins with built-in glucose sensors for glucose responsive insulin release

Abstract

Derivatization of insulin with phenylboronic acids is described, thereby equipping insulin with novel glucose sensing ability. It is furthermore demonstrated that such insulins are useful in glucose-responsive polymer-based release systems. The preferred phenylboronic acids are sulfonamide derivatives, which, contrary to naïve boronic acids, ensure glucose binding at physiological pH, and simultaneously operate as handles for insulin derivatization at LysB29. The glucose affinities of the novel insulins were evaluated by glucose titration in a competitive assay with alizarin. The affinities were in the range 15-31 mM (K(d)), which match physiological glucose fluctuations. The dose-responsive glucose-mediated release of the novel insulins was demonstrated using glucamine-derived polyethylene glycol polyacrylamide (PEGA) as a model, and it was shown that Zn(II) hexamer formulation of the boronated insulins resulted in steeper glucose sensitivity relative to monomeric insulin formulation. Notably, two of the boronated insulins displayed enhanced insulin receptor affinity relative to native insulin (113%-122%) which is unusual for insulin LysB29 derivatives.

Responsive Polymers at the Biology/Materials Science Interface

“…[53,54] Similar glucose affinity responsive polymers have been produced using polymeric boronic acids, which can reversibly esterify diols in a pH-dependent manner. [55][56][57] The selectivity of the response can be tuned by altering the characteristics of the boronic acid: ester formation with sugar diols is promoted by coordination of boron within the boronate by an amine functionality.…”

Synthesis of sulfonamide- and sulfonyl-phenylboronic acid-modified silica phases for boronate affinity chromatography at physiological pH

“…As a step towards the rational design of boronate affinity phase with pKa's near or below neutrality, we chose to synthesize sulfonyl-and sulfonamide substituted phenylboronic acids as ligands for immobilization on a solid phase. While sulfonamide phenylboronic acids have attracted attention as recognition moieties of sensors for sugars [15], sulfonyl-and sulfonamide-phenylboronic acids immobilized for affinity chromatography have not been reported. In this paper, we present the synthesis of the sulfonyl-and sulfonamidephenylboronic acid ligands and their immobilization on porous silica gels by silylation.…”

Glucose-responsive insulin activity by covalent modification with aliphatic phenylboronic acid conjugates

“…Here, we developed a strategy for the covalent modification of insulin intended to couple an aliphatic domain for long-lasting activity with PBA as a glucose-sensing element to prepare a soluble, circulating, glucose-sensing modified insulin molecule. Although PBAs have been fused to insulin previously as a method for preparing glucose-responsive self-assemblies of insulin (19,20), our report here illustrates, to our knowledge, the first demonstration of glucose-responsive activity for a PBA-modified insulin in an animal model of diabetes. Through screening of different PBAcontaining aliphatic conjugates, Ins-PBA-F was identified as the Fig.…”

“…1B). Similar methods have been previously demonstrated to afford selectivity in functionalizing this primary amine instead of either the A1 or B1 N-terminal amines of insulin (19,20). These methods resulted in four PBA-containing aliphatic insulin derivatives (Fig.…”