Lrig1 expression identifies airway basal cells with high proliferative capacity and restricts lung squamous cell carcinoma growth

Aberrant basal cell clonal dynamics shape early lung carcinogenesis

Preinvasive squamous lung lesions are precursors of lung squamous cell carcinoma (LUSC). The cellular events underlying lesion formation are unknown. Using a carcinogen-induced model of LUSC with no added genetic hits or cell type bias, we find that carcinogen exposure leads to non-neutral competition among basal cells, aberrant clonal expansions, and basal cell mobilization along the airways. Ultimately, preinvasive lesions develop from a few highly mutated clones that dominate most of the bronchial tree. Multi-site sequencing in human patients confirms the presence of clonally related preinvasive lesions across distinct airway regions. Our work identifies a transition in basal cell clonal dynamics, and an associated shift in basal cell fate, as drivers of field cancerization in the lung.

Hsa-miR-21 promoted the progression of lung adenocarcinoma by regulating LRIG1 expression

Lung cancer is the foremost cause of cancer-related fatalities globally, and lung adenocarcinoma (LUAD) is one of the common types of lung cancer with significant molecular heterogeneity. Leucine rich repeats and immunoglobulin like domains 1 (LRIG1) has been demonstrated to be down-regulated in lung cancer and related to prognosis of patients. The purpose of this work is to explore the targeting miRNAs of LRIG1, and the related regulatory mechanisms in LUAD. The data of LUAD patients were collected from The Cancer Genome Atlas and Gene Expression Omnibus databases. The differential expression analysis and gene set enrichment analysis (GSEA) were performed using "limma" and "clusterProfiler" function package, respectively. The levels of hsa-miR-21 mRNA and LRIG1 mRNA and LRIG1 protein expressions were analyzed using RT-qPCR and western blot analysis. The infiltration of immune cells was determined using CIBERSORT software. In LUAD patients, hsa-miR-21 expression was observably related to LRIG1 expression. Hsa-miR-21 might negatively modulate the LRIG1 expression in LUAD. LUAD patients with hsa-miR-21 up-regulation exhibited inferior prognosis. In addition, those with LUAD who had high hsa-miR-21 expression but low LRIG1 expression had a worse prognosis, whereas those with low hsa-miR-21 expression but high LRIG1 expression had a better prognosis. Functional enrichment analysis indicated that metabolic related signaling pathways (EGFR tyrosine kinase inhibitor resistance) were significantly activated in LUAD patients with LRIG1 up-regulation. Finally, we found that relative content of naive B cells, plasma cells and resting CD4 + T cells were significantly increased and regulatory T cells and Macrophages M0 were decreased in LRIG1 high expression group and hsa-miR-21 low expression group. We firstly reported that hsa-miR-21 might regulate the LRIG1 expression in LUAD, thereby effecting the onset and progression of LUAD. Clinical trial number: Not applicable.

Regenerative Role of Lrig1+ Cells in Kidney Repair

Key Points

Lrig1 + cells exist long term during kidney homeostasis and become activated upon injury, contributing to regeneration. Lrig1 + cells and their progeny emerge during tubulogenesis and contribute to proximal tubule and inner medullary collecting duct development. Lrig1 + cells expand and differentiate into a mature nephron lineage in response to AKI to repair the proximal tubule.

Background

In response to severe kidney injury, the kidney epithelium displays remarkable regenerative capabilities driven by adaptable resident epithelial cells. To date, it has been widely considered that the adult kidney lacks multipotent stem cells; thus, the cellular lineages responsible for repairing proximal tubule damage are incompletely understood. Leucine-rich repeats and immunoglobulin-like domain protein 1–expressing cells (Lrig1 + cells) have been identified as a long-lived cell in various tissues that can induce epithelial tissue repair. Therefore, we hypothesized that Lrig1 + cells participate in kidney development and tissue regeneration.

Methods

We investigated the role of Lrig1 + cells in kidney injury using mouse models. The localization of Lrig1 + cells in the kidney was examined throughout mouse development. The function of Lrig1 + progeny cells in AKI repair was examined in vivo using a tamoxifen-inducible Lrig1 -specific Cre recombinase-based lineage tracing in three different kidney injury mouse models. In addition, we conducted single-cell RNA sequencing to characterize the transcriptional signature of Lrig1 + cells and trace their progeny.

Results

Lrig1 + cells were present during kidney development and contributed to formation of the proximal tubule and collecting duct structures in mature mouse kidneys. In three-dimensional culture, single Lrig1 + cells demonstrated long-lasting propagation and differentiated into the proximal tubule and collecting duct lineages. These Lrig1 + proximal tubule cells highly expressed progenitor-like and quiescence-related genes, giving rise to a novel cluster of cells with regenerative potential in adult kidneys. Moreover, these long-lived Lrig1 + cells expanded and repaired damaged proximal tubule in response to three types of AKIs in mice.

Conclusions

These findings highlight the critical role of Lrig1 + cells in kidney regeneration.