P072 LDN-071, a novel first-in-class amino acid-based PAI-1 inhibitor, significantly reduces the severity of experimental colitis in mice

Abstract

Abstract Background Inflammatory Bowel Diseases (IBD) are chronic inflammatory disorders characterised by alterations of acute relapses and remission. The past decades have brought substantial advances in the pharmacological management of IBD by wide range of medicines. Although, the sustained efficacy of the currently available anti-inflammatory therapies is still far from optimal. Therefore, the development of novel therapies represents a major unmet clinical need in this field. Recently the enrichment of the coagulation pathway genes and among these, Plasminogen activator inhibitor 1 (PAI-1) was described in IBD, whereas PAI-1 emerged as a link between the epithelium and inflammation. Moreover, the genetic deletion of PAI-1 impaired the severity of experimental colitis in mice. Based on these, our aim was to develop and test novel PAI-1 inhibitors for the treatment of IBD. Methods Novel, amino acid-based PAI-1 inhibitors were synthetized by A3SMO® platform. The inhibitory potential and cytotoxicity effects of the peptides were determined by in vitro assays. Based on the in vitro results LDN-071 was selected for further analysis. Experimental colitis was induced in mice with 3% DSS and after the induction of colitis 10 mg/bwkg LDN-071 was administered per os for four consecutive days. The changes of body weight, spleen weight and colon length were measured. Haematoxylin eosin (HE) and Periodic acid-Schiff (PAS) staining were performed for histology. ELISA and qRT-PCR measurements were applied to analyse the mucosal cytokine expressions. In vivo toxicity of LDN-071 was determined in mice. Results LDN-071 significantly inhibited PAI-1 in vitro without decreasing the cell viability in a concentration range of 1µM-1mM. The administration of 10 mg/bwkg LDN-071 in the DSS-treated mice prevented the body weight loss, the development of bloody diarrhoea, the decrease of colon length and increase of the spleen weight, which were displayed by the DSS+vehicle-treated animals. The histological analysis of the colon revealed that DSS treatment induced a severe transmural inflammation, ulceration, loss of crypt structures and goblet cell depletion. Importantly, all of these parameters were significantly impaired by the administration of 10 mg/bwkg LDN-071. Additionally, mucosal gene and protein expressions of TNF-α, IL-1β and IL-6 were significantly impaired by PAI-1 inhibition. Importantly, no signs of toxicity were LDN-071 observed in mice exposed to 100 mg/bwkg LDN-071 for 7 days. Conclusion Our results showed that LDN-071, a novel amino acid-based inhibitor of PAI-1. It significantly reduces the severity of experimental colitis in mice. We propose that the inhibition of PAI-1 could be a potential novel therapeutic strategy in IBD.