The indispensability of macrophage adaptor proteins in chronic inflammatory diseases

Dorzolamide intermediates with potential anti-inflammatory activity

Dorzolamide (DZD), a Carbonic anhydrase (CA) inhibitor clinically used to lower intraocular pressure, exhibits anti-inflammatory effects owing to the drug's ability to inhibit the TIR domain-containing adaptor protein (TIRAP)-mediated signalling in macrophages. Here, we investigated whether DZD intermediates also demonstrate any anti-inflammatory property like DZD but with a reduced inhibition of CA. We found that several intermediates of DZD show increased binding to TIRAP at the common interface of kinases, such as Protein kinase C-delta (PKCδ) and Bruton's tyrosine kinase (BTK). Such binding results in a decreased activity of TIRAP, p38 Mitogen-activating protein kinases (MAPK), and p65, which are essential for major inflammatory signaling pathways. Remarkably, the DZD intermediates were more effective than DZD in decreasing the mRNA expression levels of pro-inflammatory cytokines in Lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The DZD intermediates also exhibit a reduced binding energy to CA II and CA IV, highlighting their improved specificity as anti-inflammatory compounds with decreased unwanted biological effects. Furthermore, we validated the anti-inflammatory effect of the most efficient DZD intermediate, DRZ V, in a model of mouse sepsis. DRZ V-treated septic mice exhibited improved survival compared to DZD-treated septic mice. Our data indicate that the tested DZD intermediates are more effectual in dampening TIRAP-mediated inflammatory signaling as compared to DZD. Thus, DZD intermediates may be a promising option for developing novel anti-inflammatory therapeutics.

Imperative role of adaptor proteins in macrophage toll-like receptor signaling pathways

Macrophages are integral part of the body's defense against pathogens and serve as vital regulators of inflammation. Adaptor molecules, featuring diverse domains, intricately orchestrate the recruitment and transmission of inflammatory responses through signaling cascades. Key domains involved in macrophage polarization include Toll-like receptors (TLRs), Src Homology2 (SH2) and other small domains, alongside receptor tyrosine kinases, crucial for pathway activation. This review aims to elucidate the enigmatic role of macrophage adaptor molecules in modulating macrophage activation, emphasizing their diverse roles and potential therapeutic and investigative avenues for further exploration.

Pharmacological targeting of adaptor proteins in chronic inflammation

BACKGROUND

Inflammation, a biological response of the immune system, can be triggered by various factors such as pathogens, damaged cells, and toxic compounds. These factors can lead to chronic inflammatory responses, potentially causing tissue damage or disease. Both infectious and non-infectious agents, as well as cell damage, activate inflammatory cells and trigger common inflammatory signalling pathways, including NF-κB, MAPK, and JAK-STAT pathways. These pathways are activated through adaptor proteins, which possess distinct protein binding domains that connect corresponding interacting molecules to facilitate downstream signalling. Adaptor molecules have gained widespread attention in recent years due to their key role in chronic inflammatory diseases.

METHODS

In this review, we explore potential pharmacological agents that can be used to target adaptor molecules in chronic inflammatory responses. A comprehensive analysis of published studies was performed to obtain information on pharmacological agents.

CONCLUSION

This review highlights the therapeutic strategies involving small molecule inhibitors, antisense oligonucleotide therapy, and traditional medicinal compounds that have been found to inhibit the inflammatory response and pro-inflammatory cytokine production. These strategies primarily block the protein-protein interactions in the inflammatory signaling cascade. Nevertheless, extensive preclinical studies and risk assessment methodologies are necessary to ensure their safety.

Adaptor molecules mediate negative regulation of macrophage inflammatory pathways: a closer look

Macrophages play a central role in initiating, maintaining, and terminating inflammation. For that, macrophages respond to various external stimuli in changing environments through signaling pathways that are tightly regulated and interconnected. This process involves, among others, autoregulatory loops that activate and deactivate macrophages through various cytokines, stimulants, and other chemical mediators. Adaptor proteins play an indispensable role in facilitating various inflammatory signals. These proteins are dynamic and flexible modulators of immune cell signaling and act as molecular bridges between cell surface receptors and intracellular effector molecules. They are involved in regulating physiological inflammation and also contribute significantly to the development of chronic inflammatory processes. This is at least partly due to their involvement in the activation and deactivation of macrophages, leading to changes in the macrophages' activation/phenotype. This review provides a comprehensive overview of the 20 adaptor molecules and proteins that act as negative regulators of inflammation in macrophages and effectively suppress inflammatory signaling pathways. We emphasize the functional role of adaptors in signal transduction in macrophages and their influence on the phenotypic transition of macrophages from pro-inflammatory M1-like states to anti-inflammatory M2-like phenotypes. This endeavor mainly aims at highlighting and orchestrating the intricate dynamics of adaptor molecules by elucidating the associated key roles along with respective domains and opening avenues for therapeutic and investigative purposes in clinical practice.