Glycosylated human interleukin-1alpha, neoglyco IL-1alpha, coupled with N-acetylneuraminic acid exhibits selective activities in vivo and altered tissue distribution

[Interluekin-1: from regulation of cell proliferation to chronic inflammatory diseases]

  Interleukin 1 (IL-1) was initially defined as a factor which is produced by macrophages and exhibits proliferative activity on thymocytes and fibroblasts, B cell activation and endogenous pyrogen activity. Now IL-1 is known to exhibit pleiotropic activities on various cell types and play important roles in the regulation of immune, nervous and endocrine systems, progression of tumor cells, hematopoietic cell proliferation/differentiation and especially in inflammatory diseases. In 1985 I found that IL-1 exhibits cytocidal activity against human melanoma cells. Since then I have been engaged in the research of various aspects of IL-1. This review summarizes current knowledge of IL-1, including our research and beneficial effect of IL-1 blocking on inflammatory diseases.

Glycosylation of therapeutic proteins: an effective strategy to optimize efficacy

During their development and administration, protein-based drugs routinely display suboptimal therapeutic efficacies due to their poor physicochemical and pharmacological properties. These innate liabilities have driven the development of molecular strategies to improve the therapeutic behavior of protein drugs. Among the currently developed approaches, glycoengineering is one of the most promising, because it has been shown to simultaneously afford improvements in most of the parameters necessary for optimization of in vivo efficacy while allowing for targeting to the desired site of action. These include increased in vitro and in vivo molecular stability (due to reduced oxidation, cross-linking, pH-, chemical-, heating-, and freezing-induced unfolding/denaturation, precipitation, kinetic inactivation, and aggregation), as well as modulated pharmacodynamic responses (due to altered potencies from diminished in vitro enzymatic activities and altered receptor binding affinities) and improved pharmacokinetic profiles (due to altered absorption and distribution behaviors, longer circulation lifetimes, and decreased clearance rates). This article provides an account of the effects that glycosylation has on the therapeutic efficacy of protein drugs and describes the current understanding of the mechanisms by which glycosylation leads to such effects.

Synthesis of glycosylated human tumor necrosis factor alpha coupled with N-acetylneuraminic acid

In order to study the effect of glycosylation on its biological activities, and to develop TNFalpha with less deleterious effects, recombinant human TNFalpha was chemically coupled with N-acetylneuraminic acid (NeuAc). NeuAc with C9 spacer was coupled to TNFalpha by acyl azide method. Two glycosylated TNFalphas, designated L NeuAc-TNFalpha and H NeuAc-TNFalpha, were purified by anion-exchange chromatography. NeuAc coupling to TNFalpha was confirmed by lectin blotting. Average number of carbohydrate molecules introduced per molecule of L NeuAc-TNFalpha and H NeuAc-TNFalpha were estimated to be 1.0 and 1.5, respectively. We examined a variety of TNFalpha activities in vitro, including antiproliferative or cytotoxic activities to tumor cells, proliferative effect on fibroblast cells, stimulatory effects on IL-6 production by melanoma cells and NF-kappaB activation in hepatoma cells. L NeuAc-TNFalpha and H NeuAc-TNFalpha exhibited reduced activities about 1/3 and 1/10 as compared to native TNFalpha in all the activities performed in vitro.

N-acetylneuraminic acid coupled human recombinant TNFalpha exhibits enhanced anti-tumor activity against Meth-A fibrosarcoma and reduced toxicity

In order to study the effect of glycosylation on its biological activities and to develop tumor necrosis factor α (TNFα) with less deleterious effects, N-acetylneuraminic acid (NeuAc) with a C9 spacer was chemically coupled to human recombinant TNFα. NeuAc-coupled TNFα (NeuAc-TNFα) exhibited reduced activities in vitro by about threefold compared to native TNFα. In this study, we examined a variety of TNFα activities in vivo. NeuAc-TNFα reduced activities in the up-regulation of serum levels of IL-6 and NOx, but comparable activity as native TNFα in the down-regulation of the serum level of glucose. However, NeuAc-TNFα was more potent than TNFα in the up-regulation of the serum level of serum amyloid A (SAA). NeuAc-TNFα was less toxic to mice. In addition, NeuAc-TNFα exhibited an augmented anti-tumor activity against Meth-A fibrosarcoma without hemorrhagic necrosis. These results indicate that coupling with NeuAc enabled us to develop neoglycoTNFα with selective activities in vivo, including enhanced anti-tumor activity but reduced toxicity.

Structure-activity profiles of complex biantennary glycans with core fucosylation and with/without additional alpha 2,3/alpha 2,6 sialylation: synthesis of neoglycoproteins and their properties in lectin assays, cell binding, and organ uptake

The consideration of oligosaccharides and glycoconjugates as biopharmaceuticals is an emerging topic in drug design. Chemoenzymatic synthesis of N-glycans was performed to examine the influence of N-glycan core fucosylation on lectin-binding properties and biodistribution. As a first step in a systematic comparison of N-glycans, the core fucose moiety was chemically introduced into a complex-type biantennary heptasaccharide azide. After deprotection and attachment of a spacer, the terminal sections of the N-glycan were elongated enzymatically. Conversion of the amino group in the spacer to an isothiocyanate gave derivatives allowing convenient ligand attachment to bovine serum albumin (BSA). The resulting neoglycoproteins contained an average of 2.9-4.6 chains per carrier molecule. Relative to unsubstituted biantennary complex-type N-glycans, the core fucosylation appears to favor the extended orientation of the alpha 1,6-arm. This was deduced from an up to 5-fold alteration of affinity for lectins in solid-phase assays. Marked differences were also found for cell surface binding of cultured tumor cells, for staining of tumor cells in lung sections, and in organ distribution. In vivo, the alpha 2,6-sialylated neoglycoproteins showed a reduced serum half-life in mice relative to the alpha 2,3-sialylated isomer and the non-fucosylated congeners. These results support the notion that changing the shape of a glycan provides a promising strategy to optimize the affinity of protein-carbohydrate interactions. Overall, our study underscores the importance of chemoenzymatic synthesis to define the effect of chain orientation on the ligand properties of N-glycans.