Toward a cell-type-specific lung HOX code

Area of Science:

• Developmental Biology
• Genetics
• Cell Biology

Background:

• HOX genes are transcription factors vital for embryonic development and maintaining cell identity.
• Their role in the adult human respiratory system remains largely uncharacterized.

Purpose of the Study:

• To investigate the expression patterns of HOX genes in normal adult human lung tissue.
• To identify the specific cell types expressing HOX genes within the lung.

Main Methods:

• Global gene expression analysis of normal lung tissue.
• Quantitative real-time reverse-transcriptase polymerase chain reaction (qRT-PCR).
• Analysis of single-cell RNA sequencing (scRNAseq) datasets.
• Immunohistochemistry and immunofluorescence staining.

Main Results:

• HOX gene expression was detected in various lung cells, including stromal cells, smooth muscle cells, vascular mural cells, connective tissue cells, and endothelial cells.
• HOXA and HOXB genes showed higher expression in adult lung tissue.
• Bronchial epithelial cells exhibited immunoreactivity for most examined HOX proteins, while alveolar cells showed limited HOX gene localization.
• Temporal analysis in lung organoids confirmed expression patterns.

Conclusions:

• Specific HOX genes are expressed in distinct cell types within the adult human lung.
• Understanding HOX gene localization is crucial for insights into lung diseases and potential regenerative therapies.
• Targeted modulation of cell-type-specific HOX genes may enhance regenerative potential.