The R-Spondin (RSpo) family of secreted proteins act as potent activators of the Wnt/␤-catenin signaling pathway. We have previously shown that RSpo proteins can induce proliferative effects on the gastrointestinal epithelium in mice. Here we provide a mechanism whereby RSpo1 regulates cellular responsiveness to Wnt ligands by modulating the cell-surface levels of the coreceptor LRP6. We show that RSpo1 activity critically depends on the presence of canonical Wnt ligands and LRP6. Although RSpo1 does not directly activate LRP6, it interferes with DKK1/Kremen-mediated internalization of LRP6 through an interaction with Kremen, resulting in increased LRP6 levels on the cell surface. Our results support a model in which RSpo1 relieves the inhibition DKK1 imposes on the Wnt pathway.beta-catenin ͉ DKK1 ͉ Kremen

Hepatocellular carcinoma (HCC), one of the leading causes of cancer-related death, develops from premalignant lesions in chronically damaged livers. Although it is well established that FGF19 acts through the receptor complex FGFR4-b-Klotho (KLB) to regulate bile acid metabolism, FGF19 is also implicated in the development of HCC. In humans, FGF19 is amplified in HCC and its expression is induced in the liver under cholestatic and cirrhotic conditions. In mice, ectopic overexpression of FGF19 drives HCC development in a process that requires FGFR4. In this study, we describe an engineered FGF19 (M70) that fully retains bile acid regulatory activity but does not promote HCC formation, demonstrating that regulating bile acid metabolism is distinct and separable from tumorpromoting activity. Mechanistically, we show that FGF19 stimulates tumor progression by activating the STAT3 pathway, an activity eliminated by M70. Furthermore, M70 inhibits FGF19-dependent tumor growth in a rodent model. Our results suggest that selectively targeting the FGF19-FGFR4 pathway may offer a tractable approach to improve the treatment of chronic liver disease and cancer. Cancer Res; 74(12); 3306-16. Ó2014 AACR.

Pain places a devastating burden on patients and society and current pain therapeutics exhibit limitations in efficacy, unwanted side effects and the potential for drug abuse and diversion. Although genetic evidence has clearly demonstrated that the voltage-gated sodium channel, Nav1.7, is critical to pain sensation in mammals, pharmacological inhibitors of Nav1.7 have not yet fully recapitulated the dramatic analgesia observed in Nav1.7-null subjects. Using the tarantula venom-peptide ProTX-II as a scaffold, we engineered a library of over 1500 venom-derived peptides and identified JNJ63955918 as a potent, highly selective, closed-state Nav1.7 blocking peptide. Here we show that JNJ63955918 induces a pharmacological insensitivity to pain that closely recapitulates key features of the Nav1.7-null phenotype seen in mice and humans. Our findings demonstrate that a high degree of selectivity, coupled with a closed-state dependent mechanism of action is required for strong efficacy and indicate that peptides such as JNJ63955918 and other suitably optimized Nav1.7 inhibitors may represent viable non-opioid alternatives for the pharmacological treatment of severe pain.

Hepatic accumulation of bile acids is central to the pathogenesis of cholestatic liver diseases. Endocrine hormone fibroblast growth factor 19 (FGF19) may reduce hepatic bile acid levels through modulation of bile acid synthesis and prevent subsequent liver damage. However, FGF19 has also been implicated in hepatocellular carcinogenesis, and consequently, the potential risk from prolonged exposure to supraphysiological levels of the hormone represents a major hurdle for developing an FGF19-based therapy. We describe a nontumorigenic FGF19 variant, M70, which regulates bile acid metabolism and, through inhibition of bile acid synthesis and reduction of excess hepatic bile acid accumulation, protects mice from liver injury induced by either extrahepatic or intrahepatic cholestasis. Administration of M70 in healthy human volunteers potently reduces serum levels of 7α-hydroxy-4-cholesten-3-one, a surrogate marker for the hepatic activity of cholesterol 7α-hydroxylase (CYP7A1), the enzyme responsible for catalyzing the first and rate-limiting step in the classical bile acid synthetic pathway. This study provides direct evidence for the regulation of bile acid metabolism by FGF19 pathway in humans. On the basis of these results, the development of nontumorigenic FGF19 variants capable of modulating CYP7A1 expression represents an effective approach for the prevention and treatment of cholestatic liver diseases as well as potentially for other disorders associated with bile acid dysregulation.

Objective-Increased level of plasma advanced oxidation protein products (AOPPs) has been found in patients with uremia and nonuremic subjects with coronary artery disease. This study was conducted to test the hypothesis that AOPPs play a causal role in atherosclerosis. Methods and Results-Hypercholesterolemic (0.5% wt/wt diet) or normal rabbits received either repeated intravenous injections of AOPPs modified rabbit serum albumin (AOPPs-RSA) or unmodified RSA for 8 weeks. Compared with RSA-or vehicle-treated hypercholesterolemic rabbits, AOPPs-RSA-treated animals displayed increased atherosclerotic plaque area oxidized low-density lipoprotein (oxLDL) deposition, macrophage infiltration, and smooth muscle cell proliferation. Aortic sections from AOPPs-RSA-treated normal rabbits showed significant focal intima proliferation and mild Oil-Red-O staining lipid deposition in the affected areas, a phenomenon not observed in the RSA-or vehicle-treated controls. Plasma AOPPs levels in AOPPs-treated groups significantly increased in both hypercholesterolemic and normal rabbits compared with their relevant controls. Close correlations were found between plasma levels of AOPPs and the parameters of oxidative stress, eg, oxLDL and thiobarbituric acid reactive substances levels, or glutathione peroxidase activity. A highly significant correlation was also observed between plasma AOPPs and tumor necrosis factor (TNF)-␣ levels. Key Words: advanced oxidation protein products Ⅲ atherosclerosis Ⅲ hypercholesterolemia Ⅲ inflammation Ⅲ oxidative stress T he high prevalence of atherosclerotic lesions has been amply documented in patients with chronic renal failure (CRF). 1,2 However, the factors that may promote atherosclerosis in CRF patients remain to be determined. Of particular importance in this context may be the recent observation of 3 who found that advanced oxidation protein products (AOPPs) significantly increased in patients with CRF. Conclusions-ThisBiochemical characterization has revealed that AOPPs are carried by plasma proteins, especially albumin. 3 AOPPs can be formed in vitro by exposure of serum albumin to hypochlorous acid (HOCl). In vivo, plasma concentration of AOPPs closely correlated with levels of dityrosine, a hallmark of oxidized protein, and pentosidine, a marker of protein glycoxidation tightly related to oxidative stress. 4 Thus, AOPPs might be formed during oxidative stress by reaction of plasma proteins with chlorinated oxidants, and have been considered as novel markers of oxidant-mediated protein damage. 3 More interesting is the finding that AOPPs are highly correlated to carotid intima media thickness 5 and may even be related to atherosclerotic cardiovascular events. 6 More recently, increased levels of AOPPs were also found in diabetic 7,8 and nonuremic subjects with coronary artery disease, 9 suggesting that accumulation of AOPPs may be relevant in atherosclerosis and not uremia-specific. However, although the observational studies suggest a close relationship between AOPPs and atherosclerosis,...