The human adrenal gland proteome defined

The adrenal glands are small endocrine glands located right on top of the kidneys. Each gland has two parts, the adrenal cortex and the adrenal medulla.

In a recent publication in Endocrinology, researchers from the Human Protein Atlas have performed a comprehensive analysis of the gene expression landscape of the adrenal glands to define genes with different degrees of "specific" expression compared to 31 other normal human organs and tissue types. The analysis showed that only 253 genes (approximately 1% of all putative protein coding genes) showed some level of adrenal gland specific expression pattern.

The adrenal gland is a composite endocrine organ with vital functions that include the synthesis and release of glucocorticoids and catecholamines. To define the molecular landscape that underlies the specific functions of the adrenal gland, the researchers combined a genome-wide transcriptomics approach based on mRNA sequencing of human tissues with immunohistochemistry-based protein profiling on tissue microarrays.

Julia Bergman, first author of the publication is a PhD student in the group of professor Fredrik Pontén.

– I am a MD from the Semmelweis University in Budapest and Lund University. During my time in Budapest I received a solid education in both histology and pathology, and it was there that my interest in cancer research was initiated. A few years later I got in contact with the Human Protein Atlas and was lucky to get accepted as a PhD student within the project. In the work leading up to this publication we have looked at healthy tissue ? this was new to me, as I usually work with cancer!

The adrenal gland is an organ that comprises two different compartments and the cells in these parts are of different origin and have totally different functions. Since the RNA-seq analysis is performed on homogenized tissue it gives no information about in which part of the adrenal gland a protein is expressed.

– My task was to map the protein expression pattern of the genes with adrenal gland-specific expression, using immunohistochemistry. In this way we could identify in which part of the adrenal gland the protein is expressed, and make predictions on which endocrine and functional systems they are part in, Julia Bergman says.

The adrenal glands are small, endocrine organs that mainly are involved in the stress reactions of our body, and maintenance of homeostasis. Both over- and underproduction of the hormones of the adrenal glands can lead to serious diseases.

– Interestingly, some of the adrenal gland specific genes we identified were previously unknown. By describing for the first time which genes that are of special importance for the functions of adrenal glands we now hope to give other researchers the possibility to deepen the knowledge of the physiology and pathophysiology of the adrenal glands, Julia Bergman concludes.

Read the whole article in Endocrinology >>

Explore the adrenal gland-specific proteome >>

Frida Henningson Johnson