Human Olfactory Receptors: Novel Cellular Functions Outside of the Nose, 2018, Maßberg et al

[hotblack]

Human Olfactory Receptors: Novel Cellular Functions Outside of the Nose

Maßberg, Désirée; Hatt, Hanns

Abstract
Olfactory receptors (ORs) are not exclusively expressed in the olfactory sensory neurons; they are also observed outside of the olfactory system in all other human tissues tested to date, including the testis, lung, intestine, skin, heart, and blood. Within these tissues, certain ORs have been determined to be exclusively expressed in only one tissue, whereas other ORs are more widely distributed in many different tissues throughout the human body. For most of the ectopically expressed ORs, limited data are available for their functional roles. They have been shown to be involved in the modulation of cell-cell recognition, migration, proliferation, the apoptotic cycle, exocytosis, and pathfinding processes. Additionally, there is a growing body of evidence that they have the potential to serve as diagnostic and therapeutic tools, as ORs are highly expressed in different cancer tissues. Interestingly, in addition to the canonical signaling pathways activated by ORs in olfactory sensory neurons, alternative pathways have been demonstrated in nonolfactory tissues. In this review, the existing data concerning the expression, as well as the physiological and pathophysiological functions, of ORs outside of the nose are highlighted to provide insights into future lines of research.

Web | DOI | Physiological Reviews

 

[hotblack]

I became interested in olfactory receptors as a couple of related genes (OR5V1 OR5AC2) cropped up in the PrecisionLife candidate genes and were flagged in one of the clusters in the analysis I was doing.

It may not be significant, but it’s interesting. They are used for far more than smelling…

In vertebrates, the olfactory receptors are located in both the cilia and synapses of the olfactory sensory neurons and in the epithelium of the human airway. Sperm cells also express odorant receptors, which are thought to be involved in chemotaxis to find the egg cell.

Olfactory receptor - Wikipedia

en.wikipedia.org

 

[hotblack]

Rather than starting another thread, this is one of the papers quoted, and one of many from the Pluznick Lab at Johns Hopkins, here’s a list of their publications in this area and a quote from their website

G protein-coupled receptors (GPCRs) play important roles in helping the kidney to maintain homeostasis, but, there are many GPCRs which are well-expressed in the kidney but do not have a known functional role. We are interested in uncovering the roles of these “understudied” renal GPCRs. Many of these receptors are “chemosensory” GPCRs – olfactory or taste receptors – thus, we are working to understand how the kidney leverages these powerful chemosensors to help support kidney function. Several of the receptors we study are also expressed in the cardiovascular system, and thus we are also interested in how these receptors help to modulate cardiovascular function.

Olfactory receptor responding to gut microbiota-derived signals plays a role in renin secretion and blood pressure regulation

Spoiler: Authors

Pluznick, Jennifer L.; Protzko, Ryan J.; Gevorgyan, Haykanush; Peterlin, Zita; Sipos, Arnold; Han, Jinah; Brunet, Isabelle; Wan, La-Xiang; Rey, Federico; Wang, Tong; Firestein, Stuart J.; Yanagisawa, Masashi; Gordon, Jeffrey I.; Eichmann, Anne; Peti-Peterdi, Janos; Caplan, Michael J.

Abstract
Olfactory receptors are G protein-coupled receptors that mediate olfactory chemosensation and serve as chemosensors in other tissues. We find that Olfr78, an olfactory receptor expressed in the kidney, responds to short chain fatty acids (SCFAs). Olfr78 is expressed in the renal juxtaglomerular apparatus, where it mediates renin secretion in response to SCFAs. In addition, both Olfr78 and G protein-coupled receptor 41 (Gpr41), another SCFA receptor, are expressed in smooth muscle cells of small resistance vessels. Propionate, a SCFA shown to induce vasodilation ex vivo, produces an acute hypotensive response in wild-type mice. This effect is differentially modulated by disruption of Olfr78 and Gpr41 expression. SCFAs are end products of fermentation by the gut microbiota and are absorbed into the circulation. Antibiotic treatment reduces the biomass of the gut microbiota and elevates blood pressure in Olfr78 knockout mice. We conclude that SCFAs produced by the gut microbiota modulate blood pressure via Olfr78 and Gpr41.

Web | DOI | PMC | PDF | Proceedings of the National Academy of Sciences

 

[Jonathan Edwards]

I wonder if this has anything to do with OLFM4?

I would be intrigung if there was a signalling system hiding throughout the body that made use of primitive olfactory (i.e. chemical) recognition.

 

[hotblack]

It would!

OLFM4 isn’t even in the PrecisionLife gene list. Only CSE1L and DCC are in both I think. Not sure what to make of that or if it’s worth looking at a combined gene set to see what turns up…