su min (violet) hong

read_status: read
type: paper
title: "Fate mapping in mouse demonstrates early secretory differentiation directly from Lgr5+ intestinal stem cells"
year: 2025
authors:
- "Banjac, Isidora"
- "Maimets, Martti"
- "Tsang, Ingrid H.C."
- "Dioli, Marius"
- "Hansen, Stine Lind"
- "Krizic, Kata"
- "Bressan, Raul Bardini"
- "Lövkvist, Cecilia"
- "Jensen, Kim B."

journal: "Developmental Cell"
doi: "10.1016/j.devcel.2024.12.023"
url: "https://linkinghub.elsevier.com/retrieve/pii/S1534580724007627"
project:
  - EpPathobio
system:
  - intestinal_epithelium
  - intestinal_crypt
  - crypt_base_columnar_cells
  - transit_amplifying_cells

disease:
  - none

genes:
  - lgr5
  - lrig1
  - atoh1
  - lyz1

processes:
  - stem_cell_fate_choice
  - secretory_differentiation
  - absorptive_differentiation
  - cell_cycle_exit
  - lineage_tracing

methods:
  - cre_lox_fate_mapping
  - single_cell_rna_seq
  - edu_brdu_pulse_chase
  - mathematical_modeling
  - confocal_imaging

key_findings:
  - direct_secretory_commitment
  - stem_cell_bias_toward_secretory
  - transit_amplifying_amplifies_absorptive
  - early_lineage_segregation

limitations:
  - proliferation_based_cell_typing
  - short_term_fate_mapping
  - lack_of_quiescent_stem_cell_modeling

relevance:
  - conceptual_model_of_crypt_maintenance
  - quantitative_fate_logic
  - mechanistic_reframing_of_ta_role

concepts:
  - crypt_fate_segregation
  - direct_stem_cell_differentiation
  - transit_amplifying_compartment
  - lineage_tracing_models

tags:
  - gi
  - stem_cells
  - differentiation
  - fate_mapping

Abstract

The intestinal epithelium has a remarkably high turnover in homeostasis. It remains unresolved how this is orchestrated at the cellular level and how the behavior of stem and progenitor cells ensures tissue maintenance. To address this, we combined quantitative fate mapping in three complementary mouse models with mathematical modeling and single-cell RNA sequencing. Our integrated approach generated a spatially and temporally defined model of crypt maintenance based on two cycling populations: stem cells at the crypt-bottom and transit-amplifying (TA) cells above them. Subsequently, we validated the predictions from the mathematical model, demonstrating that fate decisions between the secretory and absorptive lineages are made within the stem cell compartment, whereas TA cell divisions contribute specifically to the absorptive lineage. These quantitative insights provide further direct evidence for crypt-bottom stem cells as the dominant driver of the intestinal epithelium replenishment.

Key Findings

• Lgr5+ stem cells directly differentiate into secretory lineages without passing through a proliferative progenitor.

• Secretory fate decisions occur within the stem cell compartment, not in TA cells.

• TA cells contribute almost exclusively to absorptive amplification, not secretory production.

• Most stem cells are biased toward non-dividing secretory fate, explaining absorptive dominance via TA expansion.

• All epithelial lineages emerge within ~72h while cells remain in the crypt.

Methods

• Cre-lox lineage tracing using Lgr5-CreERT2, Lrig1-CreERT2, Atoh1-CreERT2.

• EdU/BrdU double pulse to infer spatial cell-cycle kinetics.

• scRNA-seq of lineage-traced progeny at 48h and 72h.

• Mathematical modeling fit to quantitative clone size distributions.

• 3D confocal imaging of cleared whole-mount crypts.

Notes

• Reframes crypt as two-function system: stem fate decisions + TA amplification.

• Secretory differentiation is a cell-cycle exit program, not a progenitor cascade.

• Challenges models placing TA as general multipotent progenitors.

• Explains absorptive dominance via population size control, not fate bias.

• Strong quantitative link between division kinetics and lineage output

Figures / Data

• Figure 1: scRNA-seq defines Lrig1 as lower-crypt proliferative population.

• Figure 2: EdU/BrdU shows slow cycling at crypt base vs fast TA.

• Figure 3: Lgr5 clones expand symmetrically with homogeneous behavior.

• Figure 4: scRNA-seq shows secretory cells arise directly from Lgr5 lineage.

• Figure 4E: Final mechanistic model of crypt maintenance.

Limitations

• Cell types defined primarily by proliferation state, not molecular identity.

• Short-term fate mapping excludes long-term clonal behavior.

• Quiescent Mex3a+ stem cells excluded from model.

• No direct perturbation of signaling pathways controlling fate bias.