Effects of Urban Particulate Matter on the Olfactory System in a Mouse Model

Abstract

Background Exposure to urban particulate matter (UPM) is linked to the aggravation of various health problems. Although the nasal cavity is the first barrier to encounter UPM, there is a lack of studies on the impact of UPM on the olfactory area. The purpose of this study was to investigate the cytotoxic effects of UPM on mouse olfactory epithelium, the underlying pathophysiology involved, and changes in cytokine levels. Methods Mice were divided into 4 groups: control, 400UPM (administered 400 µg UPM daily; standard reference material 1649b; average particle diameter 10.5 μm) 1week, 400UPM 2weeks, and recovery 1week after 400UPM 2weeks (n = 10, 6, 6, and 6, respectively). Olfactory function was evaluated by conducting a food-finding test once a week. The olfactory neuroepithelium was harvested for histologic examination, gene ontology, quantitative real-time polymerase chain reaction, and western blotting. Results Compared to those in the control group, olfactory marker protein, olfactory receptor 1507, adenylyl cyclase 3, and GNAL mRNA levels were lower and S-100, 2′,3′-cyclic nucleotide 30-phosphodiesterase, nerve growth factor receptor-associated protein, brain-derived neurotrophic factor, and tachykinin receptor mRNA levels were higher in the 400UPM group olfactory neuroepithelium. There were no significant differences in neuroepithelial inflammatory marker levels between the 400UPM and saline group. Conclusions UPM decreased olfactory function and might have cytotoxic effects on the olfactory epithelium. Olfactory ensheathing cells and trigeminal nerve might be related to the regeneration of the olfactory epithelium after olfactory destruction associated with UPM.

Overexpression of olfactory receptor 78 ameliorates brain injury in cerebral ischaemia–reperfusion rats by activating Prkaca‐mediated cAMP/PKA‐MAPK pathway

“…Their expression in tissues other than olfactory epithelial cells has been extensively studied and increasingly reported. 7,8 Olfactory receptor 78 (Olfr78), as a member of GPCRs, has been identified the mainly receptor for Short-chain fatty acids (SCFAs), 9 which is widely expressed, such as in the brain tissues, 10 kidneys, 11 arterioles, 12 carotid bodies, 13 macrophages, 14 colon, 15 and prostate. 16 Early reports showed that SCFAs inhibit vascular calcification by regulating the osteogenic reprogramming of vascular smooth muscle cells, thereby alleviating chronic kidney injury and atherosclerosis.…”

“…Odour receptors (OR) constitute a superfamily of G protein coupled receptors (GPCRs). Their expression in tissues other than olfactory epithelial cells has been extensively studied and increasingly reported 7,8 . Olfactory receptor 78 (Olfr78), as a member of GPCRs, has been identified the mainly receptor for Short‐chain fatty acids (SCFAs), 9 which is widely expressed, such as in the brain tissues, 10 kidneys, 11 arterioles, 12 carotid bodies, 13 macrophages, 14 colon, 15 and prostate 16 .…”

Reflecting on the Work of the Giants That Come Before You

“…Roxbury et al, examine how chemosensory dysfunction affects nutrition and diet in US Adults 19 , and Kim et al, examine how urban particulate matter, increasing as pollution continues to increase in densely populated urban areas and as wildfires have affected air quality nationwide, affect the olfactory system. 20 With the myriad trials and tribulations of the past 2 years, it is easy to ignore not only the progress we have made, but the advancements yet to come. I look forward to our readers taking a moment to pause and read not just AJRA, but the numerous academic publications which we are so lucky to have, and find a moment of separation from the hectic nature of our daily lives.…”