Therapeutic TNF Inhibitors Exhibit Differential Levels of Efficacy in Accelerating Cutaneous Wound Healing

Adalimumab but neither etanercept nor certolizumab-pegol has been reported to induce a wound-healing profile in vitro by regulating macrophage differentiation and matrix metalloproteinase expression, which may underlie the differences in efficacy between various TNF-α inhibitors in impaired wound healing in patients with hidradenitis suppurativa, a chronic inflammatory skin disease. To examine and compare the efficacy of various TNF inhibitors in cutaneous wound healing in vivo, a human TNF knock-in Leprdb/db mouse model was established to model the impaired cutaneous wound healing as seen in hidradenitis suppurativa. The vehicle group exhibited severe impairments in cutaneous wound healing. In contrast, adalimumab significantly accelerated healing, confirmed by both histologic assessment and a unique healing transcriptional profile. Moreover, adalimumab and infliximab showed similar levels of efficacy, but golimumab was less effective, along with etanercept and certolizumab-pegol. In line with histologic assessments, proteomics analyses from healing wounds exposed to various TNF inhibitors revealed distinct and differential wound-healing signatures that may underlie the differential efficacy of these inhibitors in accelerating cutaneous wound healing. Taken together, these data revealed that TNF inhibitors exhibited differential levels of efficacy in accelerating cutaneous wound healing in the impaired wound-healing model in vivo.

Design and Construction of a Synthetic Nanobody Library: Testing Its Potential with a Single Selection Round Strategy

Nanobodies (Nbs) are single domain antibody fragments derived from heavy-chain antibodies found in members of the Camelidae family. They have become a relevant class of biomolecules for many different applications because of several important advantages such as their small size, high solubility and stability, and low production costs. On the other hand, synthetic Nb libraries are emerging as an attractive alternative to animal immunization for the selection of antigen-specific Nbs. Here, we present the design and construction of a new synthetic nanobody library using the phage display technology, following a structure-based approach in which the three hypervariable loops were subjected to position-specific randomization schemes. The constructed library has a clonal diversity of 10⁸ and an amino acid variability that matches the codon distribution set by design at each randomized position. We have explored the capabilities of the new library by selecting nanobodies specific for three antigens: vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF) and the glycoprotein complex (GnGc) of Andes virus. To test the potential of the library to yield a variety of antigen-specific Nbs, we introduced a biopanning strategy consisting of a single selection round using stringent conditions. Using this approach, we obtained several binders for each of the target antigens. The constructed library represents a promising nanobody source for different applications.

Microscale thermophoresis as a powerful growing analytical technique for the investigation of biomolecular interaction and the determination of binding parameters

The in vitro panel of technologies to address biomolecular interactions are in play, however microscale thermophoresis is continuously increasing in use to represent a key player in this arena. This review highlights the usefulness of microscale thermophoresis in the determination of molecular and biomolecular affinity interactions. This work reviews the literature from January 2016 to January 2022 about microscale thermophoresis. It gives a summarized overview about both the state-of the art and the development in the field of microscale thermophoresis. The principle of microscale thermophoresis is also described supported with self-created illustrations. Moreover, some recent advances are mentioned that showing application of the technique in investigating biomolecular interactions in different fields. Finally, advantages as well as drawbacks of the technique in comparison with other competing techniques are summarized.

A trivalent TNF-R2 as a new tumor necrosis factor alpha-blocking molecule

The neutralization of tumor necrosis factor alpha (TNFα) with biopharmaceuticals is a successful therapy for inflammatory diseases. Currently, one of the main TNFα-antagonists is Etanercept, a dimeric TNF-R2 ectodomain. Considering that TNFα and its receptors are homotrimers, we proposed that a trimeric TNF-R2 ectodomain could be an innovative TNFα-antagonist. Here, the 3cTNFR2 protein was designed by the fusion of the TNF-R2 ectodomain with the collagen XV trimerization domain. 3cTNFR2 was produced in HEK293 cells and purified by immobilized metal affinity chromatography. Monomers, dimers, and trimers of 3cTNFR2 were detected. The interaction 3cTNFR2-TNFα was assessed. By microscale thermophoresis, the K_D value for the interaction was 4.17 ± 0.88 nM, and complexes with different molecular weights were detected by size exclusion chromatography-high performance liquid chromatography. Moreover, 3cTNFR2 neutralized the TNFα-induced cytotoxicity totally in vitro. Although more studies are required to evaluate the anti-inflammatory effect, the results suggest that 3cTNFR2 could be a TNFα-antagonist agent.

Design and characterization of a novel dimeric blood-brain barrier penetrating TNFα inhibitor

Tumor necrosis factor-alpha (TNFα) inhibitors could prevent neurological disorders systemically, but their design generally relies on molecules unable to cross the blood-brain barrier (BBB). This research was aimed to design and characterize a novel TNFα inhibitor based on the angiopeptide-2 as a BBB shuttle molecule fused to the extracellular domain of human TNFα receptor 2 and a mutated vascular endothelial growth factor (VEGF) dimerization domain. This new chimeric protein (MTV) would be able to trigger receptor-mediated transcytosis across the BBB via low-density lipoprotein receptor-related protein-1 (LRP-1) and inhibit the cytotoxic effect of TNFα more efficiently because of its dimeric structure. Stably transformed CHO cells successfully expressed MTV, and its purification by Immobilized-Metal Affinity Chromatography (IMAC) rendered high purity degree. Mutated VEGF domain included in MTV did not show cell proliferation or angiogenic activities measured by scratch and aortic ring assays, which corroborate that the function of this domain is restricted to dimerization. The pairs MTV-TNFα (Kd 279 ± 40.9 nM) and MTV-LRP1 (Kd 399 ± 50.5 nM) showed high affinity by microscale thermophoresis, and a significant increase in cell survival was observed after blocking TNFα with MTV in a cell cytotoxicity assay. Also, the antibody staining in CHOK1 and bEnd3 cells demonstrated the adhesion of MTV to the LRP1 receptor located in the cell membrane. These results provide compelling evidence for the proper functioning of the three main domains of MTV individually, which encourage us to continue the research with this new molecule as a potential candidate for the systemic treatment of neurological disorders.

Adalimumab Induces a Wound Healing Profile in Patients with Hidradenitis Suppurativa by Regulating Macrophage Differentiation and Matrix Metalloproteinase Expression

Adalimumab (ADA) is the only Food and Drug Administration‒approved treatment for moderate-to-severe hidradenitis suppurativa, whereas etanercept and certolizumab-pegol have been shown to be ineffective, suggesting that the mechanism of action of ADA is distinct in hidradenitis suppurativa and may contribute to improved wound healing. Given that macrophages (Mϕs) play pivotal roles throughout the wound healing process, an in vitro Mϕ differentiation assay was carried out to assess the impact of TNF‒anti-TNF complexes on these cells. TNF‒ADA complexes exhibited stronger inhibitory effects on inflammatory Mϕ differentiation. Moreover, RNA sequencing revealed several unique wound healing profiles for TNF‒ADA‒treated inflammatory Mϕs, which were not observed for those treated with either TNF‒etanercept or TNF‒certolizumab-pegol complexes, including the inhibition of the matrix metalloproteinase (MMP) pathway. In addition, ADA administration was found to significantly reduce the levels of inflammatory MMP-1 and MMP-9 while promoting wound-healing MMP-13 and tissue inhibitor of metalloproteinases 2 levels in the circulation of the patients with hidradenitis suppurativa who responded to treatment. Our in vitro findings show that TNF‒ADA‒treated inflammatory Mϕs exhibit a distinct profile resembling wound healing. Moreover, ADA not only differentially regulates MMP expression in patients with hidradenitis suppurativa responding to the therapy but also potentially induces a transition to a profile suggestive of wound healing.