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Preprint WatchStrongOctober 4th, 2026

RasGRP1 promotes efficient intestinal tuft cell differentiation

Shechtman, L. A.; Depeille, P.; Smith, E.; Liang, H.-E.; Tam, T. S. Y.; Duflock, A.; Cortez, V. S.; O'Leary, C. E.; Shen, A.; Bos, W.; Fragiadakis, G. K.; combes, a. K.; Gonzalez, H.; Locksley, R. M.; Roose, J. P.

RasGRP1 restrains EGFR-driven proliferation at the intestinal progenitor stage, and EGFR inhibition restores tuft cell numbers in Rasgrp1-deficient organoids.

Strong contradiction

3 prior failures

Three or more documented clinical failures match this mechanism, or a Phase 3 efficacy failure is on record.

Severity is set by the Claidex graph rather than by this preprint's proximity to oncology. Three EGFR failures are on file, tak-186-mvc-101-egfr-cd3-cobra-solid-tumors-phase1-2-efficacy-failure (efficacy failure), fpi-2107-egfr-cmet-nsclc-dosimetry-uptake-failure (translational mismatch) and bg-60366-egfr-cdac-nsclc-strategic-shutdown (sponsor decision), which triggers the STRONG threshold. The read-across is weak and should be treated as such: EGFR is a secondary subject here, the system is normal intestinal epithelium rather than tumor, and the claim concerns progenitor proliferation rather than antitumor activity. The one transferable point is that EGFR signaling output is set by upstream regulators such as RasGRP1 in a cell-state-dependent way, which is consistent with the translational mismatch recorded for FPI-2107, where target expression did not predict delivery.

Abstract excerpt

Intestinal stem and progenitor cells balance proliferation and lineage commitment to maintain epithelial homeostasis and adapt to environmental challenges. Tuft cells are a rare chemosensory lineage that rapidly expands in response to the cytokine IL-13 during helminth infection, yet how epithelial progenitor states influence this response remains incompletely understood. Using genetic mouse models, intestinal organoids, and single-cell approaches, we identify the Ras guanine nucleotide exchange factor RasGRP1 as an epithelial-intrinsic promoter of efficient tuft cell differentiation. Rasgrp1 is expressed in rare crypt epithelial cells distinct from Lgr5-positive stem cells. Once cells entered the tuft cell differentiation trajectory, Rasgrp1 deficiency has little impact on tuft cell maturation, including expression of the Pou2f3 tuft cell transcription factor. Instead, RasGRP1 acts at the progenitor stage, where it restrains EGFR-driven proliferation and supports a transcriptionally heterogeneous transit-amplifying state, including a subset of cells expressing Pou2f3, that is largely lost upon Rasgrp1 deficiency. Consistent with this model, EGFR inhibition restores tuft cell numbers in Rasgrp1-deficient organoids and cooperates with IL-13 to enhance tuft cell differentiation. Rasgrp1-deficient mice exhibit delayed tuft cell hyperplasia and inefficient helminth clearance. Conversely, constitutive epithelial RasGRP1 overexpression, uncoupled from its endogenous regulation, drives spontaneous tuft cell hyperplasia and accelerates parasite clearance, but alters the balance of intestinal epithelial lineages. Together, our findings identify RasGRP1 as a cell-intrinsic regulator that restrains progenitor proliferation and promotes responsiveness to IL-13, thereby coupling growth factor signaling, cell cycle control, and immune-driven epithelial lineage specification.

Matching Claidex post-mortems

3 of 3 indexed

This is an automated contradiction flag, not an editorial judgment on the preprint's quality. Flags identify where the preclinical literature and the clinical failure record diverge.