Serine protease inhibitors to treat inflammation: a patent review (2011-2016) Feryel Soualmia, Chahrazade El Amri To cite this version: Feryel Soualmia, Chahrazade El Amri. Serine protease inhibitors to treat inflammation: a patent review (2011-2016). Expert Opinion on Therapeutic Patents, Informa Healthcare, In press, 28 (2), pp.93-110. 10.1080/13543776.2018.1406478. hal-01656928 HAL Id: hal-01656928 https://hal.sorbonne-universite.fr/hal-01656928 Submitted on 6 Dec 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Serine protease inhibitors to treat inflammation: a patent review (2011-2016) Feryel Soualmia and Chahrazade El Amri B2A, Biological Adaptation and Ageing, Integrated Cellular Ageing and Inflammation, Molecular & Functional Enzymology, Sorbonne Universités, UPMC Univ Paris 06, UMR 8256, Paris, France ABSTRACT Introduction: Inflammation is a physiological part of the complex biological response of tissues to counteract various harmful signals. This process involves diverse actors such as immune cells, blood vessels, and nerves as sources of mediators for inflammation control. Among them serine proteases are KEYWORDS key elements in both physiological and pathological inflammation. Serine proteases; Areas covered: Serine protease inhibitors to treat inflammatory diseases are being actively investigated inflammation; therapeutical by various industrial and academic institutions. The present review covers patent literature on serine inhibitors; kallikreins; protease inhibitors for the therapy of inflammatory diseases patented between 2011 and 2016. plasmin; neutrophil elastase; Expert opinion: Serine proteases regulating inflammation are versatile enzymes, usually involved in skin inflammation; lung proinflammatory cytokine production and activation of immune cells. Their dysregulation during inflammation; inflammation can have devastating consequences, promoting various diseases including skin and gastrointestinal inflammation lung inflammation, neuroinflammation, and inflammatory arthritis. Several serine proteases were selected for their contribution to inflammatory diseases and significant efforts that are spread to develop inhibitors. Strategies developed for inhibitor identification consist on either peptide-based inhibitor derived from endogenous protein inhibitors or small-organic molecules. It is also worth noting that among the recent patents on serine protease inhibitors related to inflammation a significant number are related to retinal vascular dysfunction and skin diseases. 1. Introduction no longer necessary [9]. This regulation makes it possible to preserve the homeostasis of the numerous physiological systems Proteolytic enzymes or proteases catalyze the hydrolysis of the in which the proteases are involved [10]. More than one-third of established peptide bonds between the amino acids of the pro- human proteases are serine proteases. These are probably the teins and peptides. Much more than degradation enzymes, they enzymes that are the most studied in detail [1,2]. They are char- are considered nowadays as important signaling molecules, acterized by a catalytic serine residue that acts as a nucleophile involved in many physiological processes that are highly con- and are involved in a wide variety of processes such as digestion, trolled [1,2]. Furthermore, their deregulation is often associated development, blood coagulation, fibrinolysis, immune response, with pathologies ranging from cardiovascular and inflammatory prohormone cleavage, signal transduction, and complement disorders to cancer and neurological disorders [3,4]. They are fixation [11]. In this review, after the description of the role and therefore very attractive biological targets for the identification features of selected serine proteases in inflammatory diseases, we and design of pharmacological molecules that can modulate will give an overview of current patents on serine proteases their activity [3]. The literature is full of examples of compounds inhibitors. Particularly, we will place emphasis on their diversity targeting proteases, which have reached clinical phase and/or in term of chemical scaffolds and clinical field of application. placed on the market, illustrating perfectly the considerable interest that is brought to them by the academic and industrial laboratories [3,5](Table 1). Given not only the success of a num- 2. Serine protease main features ber of flagship protease inhibitors in the treatment of hyperten- sion, hepatitis C, or HIV triple therapy [5] but also the lessons In human, serine proteases exert their activities at various cellular learned from the failures [3,7], the interest for synthetic modula- levels and are responsible for the coordination of many physio- tors of proteases remains constant [8]. The development of such logical functions including digestion, cell cycle, coagulation, compounds must then be based on a precise knowledge of their immunity, and reproduction [2]. Furthermore, serine proteases catalytic mechanism and structure [2]. In the body, proteases are are key elements of the inflammation response due to their subjected to strict regulation. They are often initially secreted as release from activated leukocytes and mast cells or generation inactive forms or ‘zymogenic’ precursors, whose cleavage of the through the coagulation cascade [12,13]. N-terminal end allows their activation into mature enzyme. The dysregulation of serine proteases is thus involved in a Moreover, direct regulation of the proteases is ensured by endo- wide range of pathologies: thrombin and plasmin in coagu- genous inhibitors which reduce their catalytic activity when this is lopathies and bleeding disorders, granzymes and neutrophil CONTACT Chahrazade El Amri [email protected] The specificity of cleavage of a given protease is based on the Article highlights interaction of a protein or peptide substrate with the residues of ● In this review, we focus on the serine proteases involved in inflam- the protease at the active site. The surface of the protease that is matory diseases capable of hosting a side chain of a single substrate residue is ● Selected inhibitor patents are reported for the 2011-2016 period with referred to as the ‘subsite’ [20–22]. The subsites are numbered a special emphasis for kallikreins, plasmin and neutrophil elastase – ● The inhibitors can be divided in two categories: (i) heterocycles and from either side of the cleavage site: S1 Sn to the N-terminus and (ii) peptidic or peptidomimetic entities inspired from substrates or toward S1′–Sn′ to the C-terminus of the substrate. The corre- macromolecular natural inhibitors sponding residues on the substrate are numbered P1–Pn and ● The most successful inhibitor group is this of heterocycles that – includes: triazoles, benzylamine, benzoxazinones, pyrroles, coumarins. P1′ Pn′, respectively [1,20]. The structure of the active site of the ● Skin inflammatory diseases (Netherton Syndrome, atopic dermatitis, protease thus determines the nature of the residues of the sub- psoriasis, rosacea) and lung inflammation constitute among the most strate which can bind specifically to the enzyme [1]. dynamic therapeutical areas within the analyzed time period ● Several preclinical studies on serine protease inhibitors were per- Depending on their specificity for cleaved residues (P1), formed in the context of joint diseases (neutrophil elastase) serine proteases can be classified as trypsin, chymotrypsin, or ● GI inflammatory diseases (Crohn’s disease, ulcerative colitis) are elastase analogs. This specificity is guided by the size and under consideration for the targeting of serine proteases (trypsin- like proteases). nature of the residue involved in the catalytic pocket of the enzyme. Trypsin or trypsin-like (TL) analogs cleave after a This box summarizes key points contained in the article. positively charged residue (lysine or arginine). Their pocket S1 being narrow, deep, and negatively charged. The S1 pocket of ‘chymotrypsin-like (CTL)’ is broad and hydrophobic in nat- ure, this results in a specificity for medium or large hydropho- elastases (NEs) in immune deficiencies [12], and plasma kal- bic residues (tyrosine, phenylalanine, and leucine) [21,22]. likreins levels in blood pressure disorders like angioe- Elastase-like has a reduced pocket that receives short and dema [14]. uncharged residues [21]. For example, those which have a In the epidermis, serine proteases, including some kallik- digestive role, such as chymotrypsin, generally have few rein-related peptidases that we will detail hereafter and requirements with respect to the substrate and a large hydro- matriptase, are involved in various skin disorders [15–18]. phobic residue in position P1 is sufficient. The activity of other Serine proteases which possess similar structures and catalytic proteases can be also based on the recognition of a complete properties are grouped into clans. The four main clans are clan peptide portion, such as, enterokinase which requires the PA represented