Modulating Interleukins and their Receptors Interactions with Small Chemicals Using In Silico Approach for Asthma

Asthma is a complex, heterogeneous, airway inflammatory disorder broadly classified into atopic (IgE mediated) and non-atopic asthma. Monoclonal antibodies (MAbs) and small chemical protein-protein interaction modulators (PPIMs) are targeted against interleukins (ILs), which play a critical role in asthma. Many MAbs are targeted against ILs and IgE. Anti IgE MAb (Omalizumab) and Anti IL-5 MAbs (Mepolizumab, Reslizumab) have only been approved by FDA. Most of the MAbs including Tracolizumab, Lebrikizumab, Anrukinzumab (Anti IL-13 MAb), and Brodalumab (Anti IL-17 MAb) are in different phases of clinical trials. Pascolizumab (Anti IL-4 MAb), however, has failed. These MAbs are expensive and may render adverse immune response. Thus, small chemical modulators targeting ILs and their receptors (IL-Rs) are being exploited computationally and further validated experimentally. The complex ILs and IL-Rs available in PDB are best suited for these types of studies. A large number of small chemical modulators against protein-protein interactions (PPIs) have been compiled in a few databases like TIMBAL, 2P2I DB and IPPIDB. Small chemical libraries are used for virtual screening to find novel modulators targeting IL-R binding interface on IL. Molecular dynamic simulations have been further used for disruption mechanism and kinetic studies. IL-2/IL-2R was targeted with clinically tested small molecule modulators like SP4206, and IL-2 levels were known to increase in non-atopic asthma. In the absence of experimentally known modulators against atopic asthma, computational tools are being explored. For example, IL-33 is a target for atopic asthma where IL-33 and its receptor complex structure is available in PDB. In summary, small chemical modulators against ILs are a complementary approach to MAbs and computational tools have been used for identifying these modulators for asthma.