Corticosterone Upregulates Gene and Protein Expression of Catecholamine Markers in Organotypic Brainstem Cultures

Abstract

Glucocorticoids are produced by the adrenal cortex and regulate cell metabolism in a variety of organs. This occurs either directly, by acting on specific receptors in a variety of cells, or by stimulating catecholamine expression within neighbor cells of the adrenal medulla. In this way, the whole adrenal gland may support specific metabolic requirements to cope with stressful conditions from external environment or internal organs. In addition, glucocorticoid levels may increase significantly in the presence of inappropriate secretion from adrenal cortex or may be administered at high doses to treat inflammatory disorders. In these conditions, metabolic alterations and increased blood pressure may occur, although altered sleep-waking cycle, anxiety, and mood disorders are frequent. These latter symptoms remain unexplained at the molecular level, although they overlap remarkably with disorders affecting catecholamine nuclei of the brainstem reticular formation. In fact, the present study indicates that various doses of glucocorticoids alter the expression of genes and proteins, which are specific for reticular catecholamine neurons. In detail, corticosterone administration to organotypic mouse brainstem cultures significantly increases Tyrosine hydroxylase (TH) and Dopamine transporter (DAT), while Phenylethanolamine N-methyltransferase (PNMT) is not affected. On the other hand, Dopamine Beta-Hydroxylase (DBH) increases only after very high doses of corticosterone.

Chronic treatment with corticosterone increases the number of tyrosine hydroxylase-expressing cells within specific nuclei of the brainstem reticular formation

“…To assess the specific placement of increased TH-positive cells, which occurred following corticosterone administration in vivo, a stereological quantification was carried out by differentiating the cranial (Bregma −3.8/Bregma −5.82) from the caudal (Bregma −6.36/Bregma −7.64) part of the brainstem. Differing from in vitro data reporting an increase of TH in the caudal nuclei only (Busceti et al, 2019), the present investigation carried out ex vivo indicates that corticosteroneinduced increase in the number of TH-immunopositive cells similarly occurs within cranial and caudal parts of the mouse brainstem (Figures 8B,C, respectively).…”

“…Thus, the present data obtained in the whole brainstem indicates that chronic corticosterone elevates TH-positive cells within the RRF within the rostral brainstem, which differs from organotypic cell cultures where no effect was detected neither in slices from the pons nor the mesencephalon (Busceti et al, 2019).…”

HIF1α is a direct regulator of steroidogenesis in the adrenal gland

“…Previous reports have stated that glucocorticoids can regulate catecholamine production in the adrenal medulla [40,41]; therefore, we also measured dopamine, norepinephrine, and epinephrine levels in the samples used to quantify steroid levels (as above). However, we found no difference between P2H1 and WT littermates in any of the catecholamines quantified (Supplementary Fig.…”

Organotypic modeling of SARS-CoV-2 lung and brainstem infection

“…The highly standardized lung organotypic cultures we describe can be extended to several small animal models. Organotypic brainstem cultures have been previously characterized using 3 to 18 days old mice or rats; with a focus on brain development, neuronal respiratory networks and neurodegenerative diseases [37][38][39][40] . Our study provides a rst characterization of these models for the rst 4 days of infection.…”