Structural and pharmacological basis for the induction of mitochondrial biogenesis by formoterol but not clenbuterol

Robert B. Cameron,Rick G. Schnellmann,Craig C. Beeson,Yuri K. Peterson

doi:10.1038/s41598-017-11030-5

Robert B. Cameron, Rick G. Schnellmann + Show 2 more

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https://doi.org/10.1038/s41598-017-11030-5

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Abstract

Mitochondrial dysfunction is associated with numerous acute and chronic degenerative diseases. The beta-2 adrenergic receptor (β2AR) agonist formoterol induces mitochondrial biogenesis (MB), but other β2AR agonists, such as clenbuterol, do not. We sought to identify the MB signaling pathway of formoterol and the differences in signaling between these two ligands that result in the differential induction of MB. While formoterol and clenbuterol increased cAMP, only formoterol increased the phosphorylation of Akt and its downstream target eNOS. The increase in Akt phosphorylation was Gβγ- and PI3K-dependent, and the increase in eNOS phosphorylation was Gβγ- and Akt-dependent. Only formoterol increased cGMP. Formoterol induced MB as measured by increases in uncoupled cellular respiration and PGC-1α and NDUFS1 mRNA expression and was blocked by inhibitors of Gβγ, Akt, NOS, and soluble guanylate cyclase. To identify distinct receptor-ligand interactions leading to these differences in signaling, we docked formoterol and clenbuterol to six structures of the β2AR. Compared to clenbuterol, the methoxyphenyl group of formoterol interacted more frequently with V114 and F193, while its formamide group interacted more frequently with C191. These data indicate that the unique structural features of formoterol allow it to interact with the β2AR to activate the Gβγ-Akt-eNOS-sGC pathway to induce MB.

Highlights

Mitochondrial dysfunction is associated with numerous acute and chronic degenerative diseases
Because there was no difference in cAMP accumulation between the two compounds, and previous work showed that cAMP does not produce mitochondrial biogenesis (MB) in RPTC, we concluded that β2AR is functioning normally in RPTC with respect to cAMP production but that cAMP is not necessary for β2AR-mediated MB in RPTC
MB plays a vital role in regulating cellular metabolism, differentiation, and repair, and its pharmacologic induction has great therapeutic potential in a variety of disease states[8, 9]

Summary

Introduction

Mitochondrial dysfunction is associated with numerous acute and chronic degenerative diseases. The methoxyphenyl group of formoterol interacted more frequently with V114 and F193, while its formamide group interacted more frequently with C191 These data indicate that the unique structural features of formoterol allow it to interact with the β2AR to activate the Gβγ-Akt-eNOS-sGC pathway to induce MB. Several agonists were able to induce MB similar to formoterol, several other agonists, including clenbuterol, were unable to induce MB at any concentration[15] These data suggest that a subset of biogenic β2AR agonists modulates distinct signaling pathways from non-biogenic β2AR agonists to induce MB. Because both formoterol and clenbuterol, a non MB inducer, are selective β2AR agonists[16], we sought to identify the differences in signaling between the two agonists in primary cultures of renal proximal tubule cells www.nature.com/scientificreports/

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