Profiling microRNA expression in bovine alveolar macrophages using RNA-seq

Area of Science:

• * Immunology
• * Genomics
• * Veterinary Science

Background:

• * MicroRNAs (miRNAs) are crucial gene regulators involved in immune responses.
• * Bovine alveolar macrophages (BAMs) are vital for lung immunity, but their miRNA expression is largely uncharacterized.
• * Understanding miRNA roles in BAMs is essential for addressing bovine respiratory diseases like tuberculosis.

Purpose of the Study:

• * To profile known and novel microRNA (miRNA) expression in bovine alveolar macrophages (BAMs) using RNA-sequencing.
• * To identify highly expressed miRNAs in BAMs and predict their target genes involved in immune functions.
• * To establish a reference dataset for future research on miRNA-mediated regulation in bovine lung immunity.

Main Methods:

• * High-throughput RNA sequencing (RNA-seq) was employed to analyze miRNA expression.
• * Bovine alveolar macrophages (BAMs) were isolated from healthy Holstein-Friesian calves via lung lavage.
• * Sequencing libraries were generated and analyzed to identify and quantify expressed miRNAs.

Main Results:

• * RNA-seq identified 80 expressed miRNAs in BAMs, with significant variations in expression levels.
• * Highly expressed miRNAs, including bta-miR-21, bta-let-7i, and bta-miR-155, have known roles in immunity.
• * Predicted target genes of BAM-expressed miRNAs were significantly enriched for innate immunity pathways; one novel miRNA was identified.

Conclusions:

• * This study provides the first comprehensive RNA-seq-based miRNA expression profile for bovine alveolar macrophages (BAMs).
• * The identified miRNAs, particularly miR-21, play significant roles in regulating innate immunity in bovine lung.
• * The generated dataset serves as a critical resource for future investigations into miRNA functions in bovine immune cells and disease resistance.