A Cell-Impermeable Cyclosporine A Derivative Reduces Pathology in a Mouse Model of Allergic Lung Inflammation

Abstract

Although the main regulators of leukocyte trafficking are chemokines, another family of chemotactic agents is cyclophilins. Intracellular cyclophilins function as peptidyl-protyl cis-trans isomerases and are targets of the immunosuppressive drug, cyclosporine A (CsA). Cyclophilins can also be secreted in response to stress factors, with elevated levels of extracellular cyclophilins detected in several inflammatory diseases. Extracellular cyclophilins are known to have potent chemotactic properties, suggesting they might contribute to inflammatory responses by recruiting leukocytes into tissues. The objective of the current study was to determine the impact of blocking cyclophilin activity using a cell-impermeable derivative of CsA, MM218, to specifically target extracellular pools of cyclophilins. We show that treatment with this compound in a mouse model of allergic lung inflammation: 1) demonstrates up to 80% reduction in inflammation, 2) directly inhibits the recruitment of antigen-specific CD4+ T cells, and 3) works equally well when delivered at 100-fold lower doses to the airways. Our findings suggest that cell-impermeable analogs of CsA can effectively reduce inflammatory responses by targeting leukocyte recruitment mediated by extracellular cyclophilins. Specifically blocking the extracellular function(s) of cyclophilins may provide a novel approach for inhibiting the recruitment of one of the principal immune regulators of allergic lung inflammation, antigen-specific CD4+ T cells, into inflamed airways and lungs.

Targeting Extracellular Cyclophilins Ameliorates Disease Progression in Experimental Biliary Atresia

“…CD147 is a type I transmembrane glycoprotein, a member of the immunoglobulin super-family, that is expressed by a wide array of cell types, including epithelial, endothelial and hematopoietic cells (6). CD147 is a signaling receptor for extracellular cyclophilins (Cyp) A and B (7,8), and recent publications have identified the CD147 signaling pathway induced by extracellular cyclophilins as a triggering mechanism regulating MMP expression and inflammation in atherosclerosis, rheumatoid arthritis, allergic and chronic lung disease (9)(10)(11)(12)(13)(14). Thus, we hypothesized that CD147 activation by extracellular cyclophilin may play a role in experimental BA as well.…”

“…Therefore, specific targeting of extracellular cyclophilins may be a valid therapeutic strategy to inhibit CD147-dependent pathways. MM284 is a nonimmunosuppressive cell-impermeable cyclosporine derivative that does not penetrate the plasma membrane and, therefore, cannot interact with intracellular cyclophilins and mediate intracellular immunosuppressive activity; thus MM284 targets only the extracellular pool of cyclophilins (12,18). We hypothesized that the liver inflammation associated with BA may be induced or activated by the interaction of extracellular CypA with CD147 located at the plasma membrane of hepatocytes and hepatic stellate cells, and blocking this interaction by MM284 would inhibit this inflammatory response and subsequent liver inflammation and, potentially, fibrosis.…”

Inhibition of Extracellular Cyclophilins with Cyclosporine Analog and Development of Atherosclerosis in Apolipoprotein E–Deficient Mice

“…Use of NIM811 instead of parent compound, cyclosporine A, allowed eliminating a confounding effect of immunosupression on atherosclerosis, limiting the effects of inhibition of cyclophilins. Each compound was administered every second day by intraperitoneal injection at a dose of 6.6 mg/kg; we previously found that this dose inhibited allergic lung inflammation (Balsley et al, 2010). Control mice were injected with vehicle (15% ethanol in 15% cremophore EL).…”

“…In this study we tested a hypothesis that selective inhibition of extracellular activities of cyclophilins without affecting their intracellular activities, an approach proven beneficial in allergic lung inflammation (Balsley et al, 2010), may achieve separation of proatherogenic from antiatherogenic effects of cyclophilin inhibition. This anticipation was based on predominantly proinflammatory activities exerted by extracellular cyclophilins (Bukrinsky, 2015).…”

FRET-Protease-Coupled Peptidyl-Prolyl cis-trans Isomerase Assay

“…Nonimmunosuppressive cyclosporin derivatives have reached clinical development for the treatment of hepatitis C infection. 20 Moreover, formulations of cyclosporin have also shown some promise in new therapeutic applications, for example, in traumatic brain injury, 21 muscular dystrophy, 22 respiratory diseases, 23 cardiovascular diseases, 24 and Alzheimer's disease. 25 Much effort is spent on selecting specific PPIase modulators for therapeutic approaches, and in this framework, the discovery of novel inhibitors may largely benefit from suitable assays for HTS.…”