The core neutrophil enriched transcriptome

Neutrophils are considered the first line of defense in the innate immune system, and are involved in the healing of damaged tissues and protection against infection. They capture and destroy invading micro-organisms by phagocytosis, release of bactericidal and protein-destroying compounds stored in intracellular granules, and by the generation of neutrophil extracellular traps (NETs).

In this section we detail the predicted core neutrophil transcriptome, highlighting genes classified as having predicted specificity in neutrophils in multiple tissue types. Such genes could be useful general markers for neutrophils across tissue beds, and are likely critical for neutrophil specific functions. These genes are sub-divided into 3 categories, based on the number of tissues in which they were independently classified as neutrophil enriched.

Neutrophils were profiled in 12 of the tissues featured in the Tissue Cell section.

• 9 genes predicted as enriched in neutrophils in 75-100 % tissues
• 22 genes predicted as enriched in neutrophils in 50-75 % tissues
• 42 genes predicted as enriched in neutrophils in 25-50 % tissues

Protein expression of genes enriched in neutrophils across tissue types

An example of a protein with enriched expression in neutrophils across multiple tissue types is S100 Calcium Binding Protein A9 (S100A9), which is a calcium- and zinc-binding protein with a key role in the regulation of inflammatory processes, immune response and mitochondrial homeostasis in neutrophils.

S100A9 - Lung
S100A9
S100A9 - Liver
S100A9
S100A9 - Thyroid gland
S100A9

Another example of a protein with enriched expression in neutrophils across multiple tissue types is CD177 Molecule (CD177). It has been reported that CD177 is up-regulated on the neutrophil surface upon stimulation, for example during severe bacterial infections, but relatively little is currently known about its function.

CD177 - Liver
CD177
CD177 - Lung
CD177
CD177 - Thyroid gland
CD177

The pattern recognition receptor C-type lectin domain family 4 member D (CLEC4D) is also predicted to have enriched specificity in neutrophils, and is thought to recognise bacterial and fungal antigens on cells which the neutrophil can then target.

CLEC4D - Lung
CLEC4D
CLEC4D - liver
CLEC4D

Genes with predicted specificity in neutrophils in individual tissues

A summary table of all genes with predicted high enrichment in neutrophils in profiled tissues is provided below. Identified genes are subdivided into 3 categories in each tissue, based on the difference between the enrichment score in neutrophils, compared to the other cell types profiled (see Methods Summary page for details):

• Predicted specificity: ´Very high´ - Differential score vs. other profiled cell types within the tissue >0.35
• Predicted specificity: ´High´ - Differential score vs. other profiled cell types within the tissue >0.25
• Predicted specificity: ´Moderate´ - Differential score vs. other profiled cell types within the tissue >0.15

Table 1: Genes predicted to be enriched in neutrophils by tissue type