Calreticulin and integrin alpha dissociation induces anti-inflammatory programming in animal models of inflammatory bowel disease

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn’s disease, is a chronic intestinal inflammatory condition initiated by integrins-mediated leukocyte adhesion to the activated colonic microvascular endothelium. Calreticulin (CRT), a calcium-binding chaperone, is known as a partner in the activation of integrin α subunits (ITGAs). The relationship between their interaction and the pathogenesis of IBD is largely unknown. Here we show that a small molecule, orally active ER-464195-01, inhibits the CRT binding to ITGAs, which suppresses the adhesiveness of both T cells and neutrophils. Transcriptome analysis on colon samples from dextran sodium sulfate-induced colitis mice reveals that the increased expression of pro-inflammatory genes is downregulated by ER-464195-01. Its prophylactic and therapeutic administration to IBD mouse models ameliorates the severity of their diseases. We propose that leukocytes infiltration via the binding of CRT to ITGAs is necessary for the onset and development of the colitis and the inhibition of this interaction may be a novel therapeutic strategy for the treatment of IBD

Identification of potent siRNA targeting complement C5 and its robust activity in pre-clinical models of myasthenia gravis and collagen-induced arthritis

Complement component 5 (C5), an important molecule in the complement cascade, blockade by antibodies shows clinical efficacy in treating complement-mediated disorders. However, insufficient blockading induced by single-nucleotide polymorphisms in the C5 protein or frequent development of “breakthrough” intravascular hemolysis in patients with paroxysmal nocturnal hemoglobinuria treated with eculizumab have been reported. Herein, we developed a lipid nanoparticle (LNP)-formulated siRNA targeting C5 that was efficiently delivered to the liver and silenced C5 expression. We identified a potent C5-siRNA with an in vitro IC50 of 420 pM and in vivo ED50 of 0.017 mg/kg following a single administration. Single or repeated administrations of the LNP-formulated C5-siRNA allowed robust and durable suppression of liver C5 expression in mice. Complement C5 silencing ameliorated C5b-dependent anti-acetylcholine receptor antibody-induced myasthenia gravis and C5a-dependent collagen-induced arthritis symptoms. Similarly, in nonhuman primates, a single administration of C5-siRNA/LNP-induced dose-dependent plasma C5 suppression and concomitantly inhibited serum complement activity; complement activity recovered to the pre-treatment levels at 65 days post administration, thus indicating that the complement activity can be controlled for a specific period. Our findings provide the foundation for further developing C5-siRNA delivered via LNPs as a potential therapeutic for complement-mediated diseases

Anti-Apoptotic Effects of Recombinant Human Hepatocyte Growth Factor on Hepatocytes Were Associated with Intrahepatic Hemorrhage Suppression Indicated by the Preservation of Prothrombin Time

Hepatocyte growth factor (HGF) is an endogenously expressed bioactive substance that has a strong anti-apoptotic effect. In this study, we biochemically and histologically characterized the effects of rh-HGF on in vitro human hepatocyte injury and mouse acute liver failure (ALF) models, both of which were induced by antibody-mediated Fas signaling. rh-HGF inhibited intracellular caspase-3/7 activation and cytokeratin 18 (CK-18) fragment release in both models. Histologically, rh-HGF dramatically suppressed parenchymal damage and intrahepatic hemorrhage. Among the laboratory parameters, prothrombin time (PT) was strongly preserved by rh-HGF, and PT was well correlated with the degree of intrahepatic hemorrhage. These results showed that the anti-apoptotic effect of rh-HGF on hepatocytes coincided strikingly with the suppression of intrahepatic hemorrhage. PT was considered to be the best parameter that correlated with the intrahepatic hemorrhages associated with hepatocellular damage. The action of rh-HGF might derive not only from its anti-apoptosis effects on liver parenchymal cells but also from its stabilization of structural and vasculature integrity