Innovative Strategy toward Mutant CFTR Rescue in Cystic Fibrosis: Design and Synthesis of Thiadiazole Inhibitors of the E3 Ligase RNF5.

In cystic fibrosis (CF), deletion of phenylalanine 508 (F508del) in the CF transmembrane conductance regulator (CFTR) is associated to misfolding and defective gating of the mutant channel. One of the most promising CF drug targets is the ubiquitin ligase RNF5, which promotes F508del-CFTR degradation. Recently, the first ever reported inhibitor of RNF5 was discovered, i.e., the 1,2,4-thiadiazol-5-ylidene inh-2. Here, we designed and synthesized a series of new analogues to explore the structure-activity relationships (SAR) of this class of compounds. SAR efforts ultimately led to compound 16, which showed a greater F508del-CFTR corrector activity than inh-2, good tolerability, and no toxic side effects. Analogue 16 increased the basal level of autophagy similar to what has been described with RNF5 silencing. Furthermore, co-treatment with 16 significantly improved the F508del-CFTR rescue induced by the triple combination elexacaftor/tezacaftor/ivacaftor in CFBE41o- cells. These findings validate the 1,2,4-thiadiazolylidene scaffold for the discovery of novel RNF5 inhibitors and provide evidence to pursue this unprecedented strategy for the treatment of CF.

Design, Synthesis, and Biological Evaluation of a Series of Oxazolone Carboxamides as a Novel Class of Acid Ceramidase Inhibitors.

Acid ceramidase (AC) is a cysteine hydrolase that plays a crucial role in the metabolism of lysosomal ceramides, important members of the sphingolipid family, a diversified class of bioactive molecules that mediate many biological processes ranging from cell structural integrity, signaling, and cell proliferation to cell death. In the effort to expand the structural diversity of the existing collection of AC inhibitors, a novel class of substituted oxazol-2-one-3-carboxamides were designed and synthesized. Herein, we present the chemical optimization of our initial hits, 2-oxo-4-phenyl-N-(4-phenylbutyl)oxazole-3-carboxamide 8a and 2-oxo-5-phenyl-N-(4-phenylbutyl)oxazole-3-carboxamide 12a, which resulted in the identification of 5-[4-fluoro-2-(1-methyl-4-piperidyl)phenyl]-2-oxo-N-pentyl-oxazole-3-carboxamide 32b as a potent AC inhibitor with optimal physicochemical and metabolic properties, showing target engagement in human neuroblastoma SH-SY5Y cells and a desirable pharmacokinetic profile in mice, following intravenous and oral administration. 32b enriches the arsenal of promising lead compounds that may therefore act as useful pharmacological tools for investigating the potential therapeutic effects of AC inhibition in relevant sphingolipid-mediated disorders.

The mood stabilizing properties of AF3581, a novel potent GSK-3ß inhibitor.

Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzymeand highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients. Glycogen synthase kinase 3ß (GSK-3ß) is a serine/threonine protein kinase mediating phosphorylation on serine and threonine amino acid residues of several target molecules. The enzyme is involved in the regulation of many cellular processes and aberrant activity of GSK-3ß has been linked to several disease conditions. There is now large evidence on the role of GSK-3ß in the pathophysiology of mood disturbances with special regard to bipolar disorders. In the present study we further investigated the role of GSK-3ß in bipolar disorders by studying AF3581, the prototype of a novel class of ATP-competitive GSK-3ß inhibitors having the common N-[(1- alkylpiperidin-4-yl) methyl]-1H-indazole-3-carboxamide scaffold. Based on previous studies, AF3581 inhibits GSK-3ß in the nanomolar range on purified human enzyme and highly selective with respect to other kinases. Current study demonstrates that the compound has efficacy both in the chronic mild stress paradigm of depression (mimicking the down phase of bipolar disorder) and on mice aggressiveness in the resident intruder model (mimicking the up phase). These findings underline the importance of aberrant GSK-3ß activity in the development/ maintenance of mood oscillation in this peculiar pathological condition. Moreover, the present work also suggests a therapeutic potential for selective GSK-3 ß inhibitors in the management of bipolar disorders patients.

Lead Optimization of Benzoxazolone Carboxamides as Orally Bioavailable and CNS Penetrant Acid Ceramidase Inhibitors.

Sphingolipids (SphLs) are a diverse class of molecules that are regulated by a complex network of enzymatic pathways. A disturbance in these pathways leads to lipid accumulation and initiation of several SphL-related disorders. Acid ceramidase is one of the key enzymes that regulate the metabolism of ceramides and glycosphingolipids, which are important members of the SphL family. Herein, we describe the lead optimization studies of benzoxazolone carboxamides resulting in piperidine 22m, where we demonstrated target engagement in two animal models of neuropathic lysosomal storage diseases (LSDs), Gaucher's and Krabbe's diseases. After daily intraperitoneal administration at 90 mg kg-1, 22m significantly reduced the brain levels of the toxic lipids glucosylsphingosine (GluSph) in 4L;C* mice and galactosylsphingosine (GalSph) in Twitcher mice. We believe that 22m is a lead molecule that can be further developed for the correction of severe neurological LSDs where GluSph or GalSph play a significant role in disease pathogenesis.

A biocompatible sodium alginate/povidone iodine film enhances wound healing.

In the last few years, there has been an increasing tendency to use natural polymers for the fabrication of dressings for wound and burn management. Among them, alginate, a polysaccharide extracted primarily from marine algae, exhibits attractive properties being non-toxic, hydrophilic and biodegradable. The aim of this study was to characterize the in vitro biocompatibility and the efficacy of a composite polymeric material based on sodium alginate (NaAlg) and povidone iodine (PVPI) complex in a mouse model of wound healing. The developed material combines the excellent wound healing properties of alginates with the bactericidal and fungicidal properties of PVPI, providing a controlled antiseptic release. We demonstrated that the NaAlg/PVPI films are able to reduce the inflammatory response both in human foreskin fibroblasts after lipopolysaccharide (LPS) stimulus and in rodents after wound induction. Furthermore, the NaAlg/PVPI film-treated animals showed a significantly higher wound closure compared to untreated animals at each time point considered. Interestingly, the complete wound closure was achieved within 12 days only in the film-treated group, indicating that the full-thickness wounds healed more rapidly in these animals. The results demonstrate that the NaAlg/PVPI films are biocompatible and possess healing properties that accelerate the wound closure.