Valencia, K. F. | bioRxiv Science

bioRxiv2024

Systemic effects of oral tolerance improve the healing of several and concomitant wounds in different body parts

Throughout our lives, we are continually subjected to different situations that can result in several and concomitant wounds to different parts of our body. The healing of these wounds is essential to maintaining health. Inflammation is an important step in wound healing, but in cases of intense or prolonged inflammation, pathological scarring or non-closure of the wound may occur. Assuming that leukocytes participate in wound healing and that it is possible to intervene systemically with inflammation, we investigated a way to promote better repair of multiple wounds that may occur at the same time. Oral tolerance is an immunological phenomenon that result from protein intake and that have systemic effects on inflammation. Previous works have shown that parenteral injection of tolerated proteins reduces the inflammatory infiltrate and improves skin wound healing. Herein we tested whether the injection of tolerated proteins improves the healing of several wounds in different body parts, such as on the skin of the back and in the external ear (the auricle). To induce oral tolerance to ovalbumin (OVA), eight weeks old C57BL/6 mice drank egg white diluted 1:5 in water for 3 consecutive days. Control mice drank water. Seven days after oral treatment, mice were submitted to excisional injuries in the skin of the back (6 mm) and in the ears (4 mm). Minutes before the injuries, the mice received an intraperitoneal injection of OVA + Al(OH)3. Seven and 40 days after injuries, tissue samples were collected and processed for histological analysis of the wounds. The results show that the injection of OVA in animals that drank OVA reduced the inflammatory infiltrate in all lesions. Besides, injection of OVA in animals that drank OVA promoted better organization of the extracellular matrix, with thicker and intertwined collagen fibers in the neodermis, resulting in smaller scars in the skin. Furthermore, the healing area of the ears of OVA-tolerant animals showed chondrocyte aggregates and less obvious fibrous scar tissue compared with control animals. In conclusion, systemic effects of oral tolerance positively influenced the healing of several lesions in different body parts.

immunology↗

bioRxiv2024

The impact of Library Size and Scale of Testing on Virtual Screening

Virtual libraries for ligand discovery have recently increased 10,000-fold, and this is thought to have improved hit rates and potencies from library docking. This idea has not, however, been experimentally tested in direct comparisons of larger-vs-smaller libraries. Meanwhile, though libraries have exploded, the scale of experimental testing has little changed, with often only dozens of high-ranked molecules investigated, making interpretation of hit rates and affinities uncertain. Accordingly, we docked a 1.7 billion molecule virtual library against the model enzyme AmpC {beta}-lactamase, testing 1,521 new molecules and comparing the results to the same screen with a library of 99 million molecules, where only 44 molecules were tested. Encouragingly, the larger screen outperformed the smaller one: hit rates improved by two-fold, more new scaffolds were discovered, and potency improved. Overall, 50-fold more inhibitors were found, supporting the idea that there are many more compounds to be discovered than are being tested. With so many compounds evaluated, we could ask how the results vary with number tested, sampling smaller sets at random from the 1521. Hit rates and affinities were highly variable when we only sampled dozens of molecules, and it was only when we included several hundred molecules that results converged. As docking scores improved, so too did the likelihood of a molecule binding; hit rates improved steadily with docking score, as did affinities. This also appeared true on re-analysis of large-scale results against the {sigma}2 and dopamine D4 receptors. It may be that as the scale of both the virtual libraries and their testing grows, not only are better ligands found but so too does our ability to rank them.

biophysics↗