Chemo-Enzymatic PEGylation/POxylation of Murine Interleukin-4

Therapeutic synthetic and natural materials for immunoengineering

Immunoengineering is a rapidly evolving field that has been driving innovations in manipulating immune system for new treatment tools and methods. The need for materials for immunoengineering applications has gained significant attention in recent years due to the growing demand for effective therapies that can target and regulate the immune system. Biologics and biomaterials are emerging as promising tools for controlling immune responses, and a wide variety of materials, including proteins, polymers, nanoparticles, and hydrogels, are being developed for this purpose. In this review article, we explore the different types of materials used in immunoengineering applications, their properties and design principles, and highlight the latest therapeutic materials advancements. Recent works in adjuvants, vaccines, immune tolerance, immunotherapy, and tissue models for immunoengineering studies are discussed.

Matrix Metalloproteinase-Responsive Delivery of PEGylated Fibroblast Growth Factor 2

Attachment of polyethylene glycol (PEG) chains is a common, well-studied, and Food and Drug Administration-approved method to address the pharmacokinetic challenges of therapeutic proteins. Occasionally, PEGylation impairs the activity of pharmacodynamics (PD). To overcome this problem, disease-relevant cleavable linkers between the polymer and the therapeutic protein can unleash full PD by de-PEGylating the protein at its target site. In this study, we engineered a matrix metalloproteinase (MMP)-responsive fibroblast growth factor 2 (FGF-2) mutant that was site-specifically extended with a PEG polymer chain. Using bioinspired strategies, the bioconjugate was designed to release the native protein at the desired structure/environment with preservation of the proliferative capacity in vitro on NIH3T3 cells. In vivo, hepatic exposure was diminished but not its renal distribution over time compared to unconjugated FGF-2. By releasing the growth factor from the PEG polymer in response to MMP cleavage, restored FGF-2 may enter hard-to-reach tissues and activate cell surface receptors or nuclear targets.

Bioconjugation of a Fibroblast Activation Protein Targeted Interleukin-4

Interleukin-4 (IL-4) is an immune-modulating therapeutic with growing potential for the treatment of inflammatory diseases. Current challenges of IL-4 therapy include a low serum half-life and pleiotropic activity, suggesting effective targeting of IL-4. To develop an interleukin-4 bioconjugate with rapid targeting to inflammatory disease sites, we report the chemical synthesis, bioconjugation, and in vitro characterization of a murine interleukin-4 (mIL-4) conjugate decorated with a fibroblast activation protein inhibitor (FAPI). The FAPI targeting moiety features 2,2',2″,2‴-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) to allow future biodistribution and imaging studies of the FAPI-mIL-4 bioconjugate. We demonstrated site-specific coupling of mIL-4 and FAPI-DOTA deploying chemo-enzyme and enzyme chemistries with a high purity exceeding 95%. The FAPI-DOTA modified mIL-4 was bioactive with polarization of murine macrophages into the M2 state while maintaining specific binding to FAP on fibroblast cells. Together, these results point to future in vivo use of the FAPI-mIL-4 bioconjugate to assess biodistribution and biological effects in animal models of inflammatory joint disease.

The Single-Dose Application of Interleukin-4 Ameliorates Secondary Brain Damage in the Early Phase after Moderate Experimental Traumatic Brain Injury in Mice

Activation of the interleukin-4 (IL-4) pathway ameliorates secondary injury mechanisms after experimental traumatic brain injury (TBI); therefore, we assessed the effect of a therapeutic IL-4 administration on secondary brain damage after experimental TBI. We subjected 100 C57/Bl6 wildtype mice to controlled cortical impact (CCI) and administered IL-4 or a placebo control subcutaneously 15 min thereafter. Contusion volume (Nissl staining), neurological function (hole board, video open field, and CatWalkXT®), and the immune response (immunofluorescent staining) were analyzed up to 28 days post injury (dpi). Contusion volumes were significantly reduced after IL-4 treatment up to 14 dpi (e.g., 6.47 ± 0.41 mm3 vs. 3.80 ± 0.85 mm3, p = 0.011 3 dpi). Macrophage invasion and microglial response were significantly attenuated in the IL-4 group in the acute phase after CCI (e.g., 1.79 ± 0.15 Iba-1+/CD86+ cells/sROI vs. 1.06 ± 0.21 Iba-1/CD86+ cells/sROI, p = 0.030 in the penumbra 3 dpi), whereas we observed an increased neuroinflammation thereafter (e.g., mean GFAP intensity of 3296.04 ± 354.21 U vs. 6408.65 ± 999.54 U, p = 0.026 in the ipsilateral hippocampus 7 dpi). In terms of functional outcome, several gait parameters were improved in the acute phase following IL-4 treatment (e.g., a difference in max intensity of -7.58 ± 2.00 U vs. -2.71 ± 2.44 U, p = 0.041 3 dpi). In conclusion, the early single-dose administration of IL-4 significantly reduces secondary brain damage in the acute phase after experimental TBI in mice, which seems to be mediated by attenuation of macrophage and microglial invasion.

Recent Advances in Oral and Transdermal Protein Delivery Systems

Protein and peptide drugs are predominantly administered by injection to achieve high bioavailability, but this greatly compromises patient compliance. Oral and transdermal drug delivery with minimal invasiveness and high adherence represent attractive alternatives to injection administration. However, oral and transdermal administration of bioactive proteins must overcome biological barriers, namely the gastrointestinal and skin barriers, respectively. The rapid development of new materials and technologies promises to address these physiological obstacles. This review provides an overview of the latest advances in oral and transdermal protein delivery, including chemical strategies, synthetic nanoparticles, medical microdevices, and biomimetic systems for oral administration, as well as chemical enhancers, physical approaches, and microneedles in transdermal delivery. We also discuss challenges and future perspectives of the field with a focus on innovation and translation.

Amber Light Control of Peptide Secondary Structure by a Perfluoroaromatic Azobenzene Photoswitch

The incorporation of photoswitches into the molecular structure of peptides and proteins enables their dynamic photocontrol in complex biological systems. Here, a perfluorinated azobenzene derivative triggered by amber light was site-specifically conjugated to cysteines in a helical peptide by perfluoroarylation chemistry. In response to the photoisomerization (trans→cis) of the conjugated azobenzene with amber light, the secondary structure of the peptide was modulated from a disorganized into an amphiphilic helical structure.

PEtOxylated Interferon-α2a Bioconjugates Addressing H1N1 Influenza A Virus Infection

Influenza A viruses (IAV), including the pandemic 2009 (pdm09) H1N1 or avian influenza H5N1 virus, may advance into more pathogenic, potentially antiviral drug-resistant strains (including loss of susceptibility against oseltamivir). Such IAV strains fuel the risk of future global outbreaks, to which this study responds by re-engineering Interferon-α2a (IFN-α2a) bioconjugates into influenza therapeutics. Type-I interferons such as IFN-α2a play an essential role in influenza infection and may prevent serious disease courses. We site-specifically conjugated a genetically engineered IFN-α2a mutant to poly(2-ethyl-2-oxazoline)s (PEtOx) of different molecular weights by strain-promoted azide-alkyne cyclo-addition. The promising pharmacokinetic profile of the 25 kDa PEtOx bioconjugate in mice echoed an efficacy in IAV-infected ferrets. One intraperitoneal administration of this bioconjugate, but not the marketed IFN-α2a bioconjugate, changed the disease course similar to oseltamivir, given orally twice every study day. PEtOxylated IFN-α2a bioconjugates may expand our therapeutic arsenal against future influenza pandemics, particularly in light of rising first-line antiviral drug resistance to IAV.

Polymer selection impacts the pharmaceutical profile of site-specifically conjugated Interferon-α2a

Conjugation of poly(ethylene glycol) (PEG) to biologics is a successful strategy to favorably impact the pharmacokinetics and efficacy of the resulting bioconjugate. We compare bioconjugates synthesized by strain-promoted azide-alkyne cycloaddition (SPAAC) using PEG and linear polyglycerol (LPG) of about 20 kDa or 40 kDa, respectively, with an azido functionalized human Interferon-α2a (IFN-α2a) mutant. Site-specific PEGylation and LPGylation resulted in IFN-α2a bioconjugates with improved in vitro potency compared to commercial Pegasys. LPGylated bioconjugates had faster disposition kinetics despite comparable hydrodynamic radii to their PEGylated analogues. Overall exposure of the PEGylated IFN-α2a with a 40 kDa polymer exceeded Pegasys, which, in return, was similar to the 40 kDa LPGylated conjugates. The study points to an expanded polymer design space through which the selected polymer class may result in a different distribution of the studied bioconjugates.