RESUMO
Regeneration of the adult intestinal epithelium is mediated by a pool of cycling stem cells, which are located at the base of the crypt, that express leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5). The Frizzled (FZD) 7 receptor (FZD7) is enriched in LGR5+ intestinal stem cells and plays a critical role in their self-renewal. Yet, drug discovery approaches and structural bases for targeting specific FZD isoforms remain poorly defined. FZD proteins interact with Wnt signaling proteins via, in part, a lipid-binding groove on the extracellular cysteine-rich domain (CRD) of the FZD receptor. Here we report the identification of a potent peptide that selectively binds to the FZD7 CRD at a previously uncharacterized site and alters the conformation of the CRD and the architecture of its lipid-binding groove. Treatment with the FZD7-binding peptide impaired Wnt signaling in cultured cells and stem cell function in intestinal organoids. Together, our data illustrate that targeting the lipid-binding groove holds promise as an approach for achieving isoform-selective FZD receptor inhibition.
Assuntos
Receptores Frizzled/antagonistas & inibidores , Receptores Frizzled/metabolismo , Intestinos/efeitos dos fármacos , Células-Tronco/efeitos dos fármacos , Animais , Sítios de Ligação , Células CHO , Membrana Celular/metabolismo , Cricetulus , Cristalografia por Raios X , Descoberta de Drogas , Feminino , Citometria de Fluxo , Células HEK293 , Humanos , Intestinos/citologia , Lipídeos/química , Camundongos , Camundongos Endogâmicos C57BL , Peptídeos/química , Ligação Proteica , Multimerização Proteica , Regeneração , Análise de Sequência de RNA , Transdução de Sinais/efeitos dos fármacos , Células-Tronco/patologia , Ressonância de Plasmônio de Superfície , Via de Sinalização WntRESUMO
NF-κB-inducing kinase (NIK) mediates non-canonical NF-κB signaling downstream of multiple TNF family members, including BAFF, TWEAK, CD40, and OX40, which are implicated in the pathogenesis of systemic lupus erythematosus (SLE). Here, we show that experimental lupus in NZB/W F1 mice can be treated with a highly selective and potent NIK small molecule inhibitor. Both in vitro as well as in vivo, NIK inhibition recapitulates the pharmacological effects of BAFF blockade, which is clinically efficacious in SLE. Furthermore, NIK inhibition also affects T cell parameters in the spleen and proinflammatory gene expression in the kidney, which may be attributable to inhibition of OX40 and TWEAK signaling, respectively. As a consequence, NIK inhibition results in improved survival, reduced renal pathology, and lower proteinuria scores. Collectively, our data suggest that NIK inhibition is a potential therapeutic approach for SLE.