Synthesis of AC1903 analogs as potent transient receptor potential canonical channel 4/5 inhibitors and biological evaluation

Design, synthesis and activity evaluation of novel quinazolinone compounds as TRPC5 inhibitors

The TRPC5 channel plays an important role in regulating various physiological processes, which is related to various human diseases, especially psychiatric and kidney diseases. Although the TRPC5 channel is one of the essential potential target, no drugs against TRPC5 channels have been granted in the market to date. In this study, based on the structure of hit compound ph1, we further synthesied 49 compounds of novel quinazolinone and heterocyclic fusion pyrimidinone derivatives, and their activities were evaluated by electrophysiological assays. After extensive screening, 21 compounds exhibited significant TRPC5 inhibitory activity, and compounds ph8 and ph14 displayed strong inhibitory with IC50 of 1.28 and 2.16 μM, respectively. These identified potential TRPC5 inhibitor may provide lead compounds and experimental evidence for the development of novel TRPC5 inhibitors with potential treatment for anxiety, depression, and progressive kidney disease.

The TRPC5 receptor as pharmacological target for pain and metabolic disease

The transient receptor potential canonical (TRPC) channels are a group of highly homologous nonselective cation channels from the larger TRP channel family. They have the ability to form homo- and heteromers with varying degrees of calcium (Ca2+) permeability and signalling properties. TRPC5 is the one cold-sensitive among them and likewise facilitates the influx of extracellular Ca2+ into cells to modulate neuronal depolarization and integrate various intracellular signalling pathways. Recent research with cryo-electron microscopy revealed its structure, along with clear insight into downstream signalling and protein-protein interaction sites. Investigations using global and conditional deficient mice revealed the involvement of TRPC5 in metabolic diseases, energy balance, thermosensation and conditions such as osteoarthritis, rheumatoid arthritis, and inflammatory pain including opioid-induced hyperalgesia and hyperalgesia following tooth decay and pulpitis. This review provides an update on recent advances in our understanding of the role of TRPC5 with focus on metabolic diseases and pain.

Discovery of pyridazinone derivatives bearing tetrahydroimidazo[1,2-a]pyrazine scaffold as potent inhibitors of transient receptor potential canonical 5 to ameliorate hypertension-induced renal injury in rats

Transient receptor potential canonical 5 (TRPC5) is a calcium-permeable non-selective cation channel involved in various pathophysiological processes, including renal injury. Recently, GFB-887, an investigational pyridazinone TRPC5 inhibitor, demonstrated significant therapeutic potential in a Phase II clinical trial for focal segmental glomerulosclerosis (FSGS), a rare and severe form of chronic kidney disease (CKD). In the current study, based on the structure of GFB-887, we conducted extensive structural modification to explore novel TRPC5 inhibitors with desirable drug-like properties and robust nephroprotective efficacy. A series of pyridazinone derivatives featuring a novel tetrahydroimidazo[1,2-a]pyrazine scaffold were synthesized and their activities were evaluated in HEK-293 cells stably expressing TRPC5 using a fluorescence-based Ca2+ mobilization assay. Among these compounds, compound 12 is turned out to be a potent TRPC5 inhibitor with apparent affinity comparable to the parent compound GBF-887. Compound 12 is highly selective on TRPC4/5 over TRPC3/6/7 and hERG channels, along with acceptable pharmacokinetic properties and a favorable safety profile. More importantly, in a rat model of hypertension-induced renal injury, oral administration of compound 12 (10 mg/kg, BID) efficaciously reduced mean blood pressure, inhibited proteinuria, and protected podocyte damage. These findings further confirmed the potential of TRPC5 inhibitors on the CKD treatment and provided compound 12 to be a valuable tool for exploring TRPC4/5 pathophysiology.

Discovery of N-alkyl-N-benzyl thiazoles as novel TRPC antagonists for the treatment of glioblastoma multiforme

Glioblastoma multiforme represents a substantial clinical challenge. Transient receptor potential channel (TRPC) antagonists might provide new therapeutic options for this aggressive cancer. In this study, a series of N-alkyl-N-benzoyl and N-alkyl-N-benzyl thiazoles were designed and prepared using a scaffold-hopping strategy and evaluated as TRPC6 antagonists. This resulted in the discovery of 15g, a potent TRPC antagonist that exhibited suitable inhibitory micromolar activities against TRPC3, TRPC4, TRPC5, TPRC6, and TRPC7 and displayed noteworthy anti-glioblastoma efficacy in vitro against U87 cell lines. In addition, 15g featured an acceptable pharmacokinetic profile and exhibited better in vivo potency (25 mg/kg/d) than the frontline therapeutic agent temozolomide (50 mg/kg/d) in xenograft models. Taken together, the TRPC antagonist 15g represents a promising lead compound for developing new anti-glioblastoma agents.