Role of Hepatic Stellate and Liver Sinusoidal Endothelial Cells in a Human Primary Cell Three-Dimensional Model of Nonalcoholic Steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is an inflammatory and fibrotic liver disease that has reached epidemic proportions and has no approved pharmacologic therapies. Research and drug development efforts are hampered by inadequate preclinical models. This research describes a three-dimensional bioprinted liver tissue model of NASH built using primary human hepatocytes and nonparenchymal liver cells (hepatic stellate cells, liver sinusoidal endothelial cells, and Kupffer cells) from either healthy or NASH donors.

Discovery and characterization of verinurad, a potent and specific inhibitor of URAT1 for the treatment of hyperuricemia and gout.

Gout is caused by elevated serum urate levels, which can be treated using inhibitors of the uric acid transporter, URAT1. Here, we characterize verinurad (RDEA3170), which is currently under evaluation for gout therapy. Verinurad specifically inhibits URAT1 with a potency of 25 nM.

Lesinurad, a novel, oral compound for gout, acts to decrease serum uric acid through inhibition of urate transporters in the kidney.

Background: Excess body burden of uric acid promotes gout. Diminished renal clearance of uric acid causes hyperuricemia in most patients with gout, and the renal urate transporter (URAT)1 is important for regulation of serum uric acid (sUA) levels. The URAT1 inhibitors probenecid and benzbromarone are used as gout therapies; however, their use is limited by drug-drug interactions and off-target toxicity, respectively.

Mechanism of high affinity inhibition of the human urate transporter URAT1.

Gout is caused by elevated serum urate levels, which can be treated using inhibitors of the uric acid transporter, URAT1. We exploited affinity differences between the human and rat transporters to map inhibitor binding sites in URAT1. Human-rat transporter chimeras revealed that human URAT1 serine-35, phenylalanine-365 and isoleucine-481 are necessary and sufficient to provide up to a 100-fold increase in affinity for inhibitors.

Coevolution of URAT1 and Uricase during Primate Evolution: Implications for Serum Urate Homeostasis and Gout.

Uric acid is the highly insoluble end-product of purine metabolism in humans. Serum levels exceeding the solubility threshold can trigger formation of urate crystals resulting in gouty arthritis. Uric acid is primarily excreted through the kidneys with 90% reabsorbed back into the bloodstream through the uric acid transporter URAT1.

Monitoring interactions between receptor tyrosine kinases and their downstream effector proteins in living cells using bioluminescence resonance energy transfer.

A limited number of whole-cell assays allow monitoring of receptor tyrosine kinase (RTK) activity in a signaling pathway-specific manner. We present the general use of the bioluminescence resonance energy transfer (BRET) technology to quantitatively study the pharmacology and signaling properties of the receptor tyrosine kinase (RTK) superfamily. RTK BRET-2 assays monitor, in living cells, the specific interaction between RTKs and their effector proteins, which control the activation of specific downstream signaling pathways.