RESUMEN
The shortage of cholesterol gallstones treatment intensifies the need to discover of effective small molecule drugs. Clinical follow-up and studies have found that activation of somatostatin receptor subtype 5 (SSTR5) reduce gallbladder contraction and thus increase the risk of cholesterol gallstones, implying that antagonizing SSTR5 may promote gallbladder emptying and reduce the formation of gallstones. Herein, we discovered novel SSTR5 antagonists and firstly investigated its effects on cholesterol gallstone. From loperamide, a reported seed structure with micromole activity, we identified optimal compound 23 as an SSTR5 antagonist exhibiting single-digit nanomolar potency, low hERG inhibition and oral availability. Further in vivo evaluation revealed that 23 significantly promoted gallbladder emptying. Moreover, in a mouse cholesterol gallstone model, 23 (3 mg/kg) effectively reduced the cholesterol gallstones formation, showing better efficacy than the clinical first-line drug UDCA (60 mg/kg), providing a new insight into the development of anti-gallstone drugs.
Asunto(s)
Cálculos Biliares , Animales , Ratones , Cálculos Biliares/tratamiento farmacológico , Receptores de Somatostatina , ColesterolRESUMEN
Mammalian sulfoglycolipids are comprised of two major classes of compounds, sulfatide (SO(3)-3Gal-ceramide) and seminolipid (SO(3)-3Gal-alkylacylglycerol). Sulfatide is present in relatively high levels in myelin, and seminolipid is present in testis. The sulfation of these sulfoglycolipids is catalyzed by a common enzyme, cerebroside sulfotransferase (CST). Disruption of the Cst gene in mice revealed that sulfatide and seminolipid are essential for, respectively, myelin formation and spermatogenesis. The present study describes the generation of a recombinant single-chain variable fragment (scFv) antibody against sulfoglycolipid, for use in the functional analysis of sulfoglycolipids in living cells. A positive hybridoma producing anti-sulfoglycolipid IgG3, referred to as DI8, was initially obtained by immunizing CST-null mice with an isolated sulfatide. The DI8 monoclonal antibody was found to bind specifically to sulfoglycolipids with the terminal 3-O-sulfated galactose structure, as evidenced by ELISA and thin-layer chromatogram-immunostaining. The antibody stained seminolipid on the cell surface of spermatogenic cells of wild-type testis, but it did not react with any cells in the seminiferous tubules of CST-null testis. Total RNA was extracted from this hybridoma, and cDNAs that encode the variable regions of the heavy and light chains of IgG3 were obtained by RT-PCR. These DNA fragments were linked through a DNA linker coding (Gly(4)Ser)(3), and the recombinant scFv fragment was then inserted into a phagemid vector pCANTAB 5E. The scFv antibody that was displayed at the tip of the M13 phage in the form of a g3p fusion protein bound to sulfatide. Furthermore, a soluble form of the scFv antibody was also found to bind to the sulfoglycolipids in ELISA.
Asunto(s)
Glucolípidos/inmunología , Fragmentos de Inmunoglobulinas/inmunología , Región Variable de Inmunoglobulina/inmunología , Sulfoglicoesfingolípidos/inmunología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Ensayo de Inmunoadsorción Enzimática , Femenino , Hibridomas/inmunología , Fragmentos de Inmunoglobulinas/química , Cadenas Pesadas de Inmunoglobulina/inmunología , Cadenas Ligeras de Inmunoglobulina/inmunología , Región Variable de Inmunoglobulina/química , Masculino , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Proteínas Recombinantes/inmunología , Sulfotransferasas/genética , Testículo/inmunologíaAsunto(s)
Ratones Noqueados , Vaina de Mielina/fisiología , Sulfoglicoesfingolípidos , Sulfotransferasas/deficiencia , Animales , Diferenciación Celular , Ratones , Vaina de Mielina/metabolismo , Oligodendroglía/citología , Oligodendroglía/metabolismo , Sulfoglicoesfingolípidos/metabolismo , Sulfotransferasas/genéticaRESUMEN
Mammalian sulfoglycolipids are comprised of two major members, sulfatide (SO(3)-3Gal-ceramide) and seminolipid (SO(3)-3Gal-alkylacylglycerol). Sulfatide is abundant in the myelin sheath and seminolipid is expressed on the spermatogenic cells. Cerebroside sulfotransferase (CST)-deficient mice generated by gene targeting completely lack sulfatide and seminolipid all over the body. CST-null mice manifest some neurological disorders due to myelin dysfunction, an aberrant enhancement of oligodendrocyte terminal differentiation, and an arrest of spermatogenesis, indicating that sulfation of glycolipids is essential for myelin formation and spermatogenesis. Moreover, CST-deficiency ameliorates L-selectin-dependent monocyte infiltration in the kidney after ureteral obstruction, an experimental model of renal interstitial inflammation, indicating that sulfatide is an endogenous ligand of L-selectin. Studies on the molecular mechanisms by which sulfoglycolipids participate in these biological processes are ongoing.