Modulation of Notch Processing by γ-Secretase Inhibitors Causes Intestinal Goblet Cell Metaplasia and Induction of Genes Known to Specify Gut Secretory Lineage Differentiation

Abstract

It is anticipated that gamma-secretase inhibitors (gamma-Sec-I) that modulate Notch processing will alter differentiation in tissues whose architecture is governed by Notch signaling. To explore this hypothesis, Han Wistar rats were dosed for up to 5 days with 10-100 micromol/kg b.i.d. gamma-Sec-I from three chemical series that inhibit Notch processing in vitro at various potencies (Notch IC(50)). These included an arylsulfonamide (AS) (142 nM), a dibenzazepine (DBZ) (1.7 nM), and a benzodiazepine (BZ) (2.2 nM). The DBZ and BZ caused dose-dependent intestinal goblet cell metaplasia. In contrast, the AS produced no detectable in vivo toxicity, despite higher exposure to free drug. In a time course using BZ, small intestinal crypt cell and large intestinal glandular cell epithelial apoptosis was observed on days 1-5, followed by goblet cell metaplasia on days 2-5 and crypt epithelial and glandular epithelial regenerative hyperplasia on days 4-5. Gene expression profiling of duodenal samples from BZ-dosed animals revealed significant time-dependent deregulation of mRNAs for various panendocrine, hormonal, and transcription factor genes. Somatostatin, secretin, mucin, CCK, and gastrin mRNAs were elevated twofold or more by day 2, and a number of candidate "early-predictive" genes were altered on days 1-2, remaining changed for 4-5 days; these included Delta1, NeuroD, Hes1-regulated adipsin, and the Hes-regulated transcriptional activator of gut secretory lineage differentiation, the rat homolog of Drosophila atonal, Rath1. Western blotting of fecal protein from BZ-and DBZ-dosed animals exhibited increased levels of both anti-Rath1 reactive protein and anti-adipsin reactive proteins, confirming their potential value as noninvasive biomarkers of intestinal goblet metaplasia.

Promotion of Colorectal Cancer Invasion and Metastasis through Activation of NOTCH–DAB1–ABL–RHOGEF Protein TRIO

“…For example, activation of NOTCH signaling in the intestinal epithelium causes expansion of the proliferating cell population ( 36 ), whereas its suppression by a γ-secretase inhibitor reduces proliferation and causes goblet cell metaplasia ( 37 ). NOTCH signaling is crucial for the maintenance of intestinal crypt bottom columnar stem cells ( 38 ).…”

Heterogeneity of Jagged1 expression in human and mouse intestinal tumors: implications for targeting Notch signaling

“…The Notch signaling pathway is a key determinant of intestinal epithelial cell self-renewal and allocation of these cells to specific differentiation lineages (Milano et al, 2004;Fre et al, 2005;Stanger et al, 2005;van Es et al, 2005). In mammals, four Notch genes are expressed, each of which encodes a single-pass transmembrane receptor (Notch1-4).…”

97 BRG1 Plays an Essential Role in Development and Homeostasis of the Duodenum Through Regulation of Notch Signaling

“…A previous study shows that apoptotic cells are increased only in crypt lesions in adult Brg1 mutant mice (Holik et al, 2013). Similarly, crypt-restricted apoptosis increased in the adult Notch inactivation models (Milano et al, 2004). In contrast, in the embryonic Notch inactivation models, increased apoptosis is widely observed in the intestine (Ueo et al, 2012).…”

“…In particular, Notch signaling plays a crucial role in the regulation of progenitor cell proliferation and differentiation (Sancho et al, 2015). Notch activity promotes differentiation into the absorptive-type cell lineage rather than the secretory cell lineage (Fre et al, 2005;Jensen et al, 2000;Milano et al, 2004;Ueo et al, 2012;van Es et al, 2005;VanDussen et al, 2012;Wong et al, 2004;Yang et al, 2001). Complete inhibition of Notch signaling in the murine intestinal epithelium using γ-secretase inhibitors results in significantly elevated differentiation into secretory lineages (Milano et al, 2004;van Es et al, 2005;Wong et al, 2004).…”

“…Notch activity promotes differentiation into the absorptive-type cell lineage rather than the secretory cell lineage (Fre et al, 2005;Jensen et al, 2000;Milano et al, 2004;Ueo et al, 2012;van Es et al, 2005;VanDussen et al, 2012;Wong et al, 2004;Yang et al, 2001). Complete inhibition of Notch signaling in the murine intestinal epithelium using γ-secretase inhibitors results in significantly elevated differentiation into secretory lineages (Milano et al, 2004;van Es et al, 2005;Wong et al, 2004). On the other hand, persistent expression of the Notch intercellular domain (ICD) expands the proliferative zone and represses secretory cell differentiation (Fre et al, 2005;Stanger et al, 2005).…”