Researchers at the Massachusetts General Hospital (MGH) have discovered a new role for a hormonal receptor involved in the sensory system early in development of the nasal brush. As reported in Nature Neuroscience, the hormone receptor — called ERα — is found in the nasal cavity within nerve cells that are part of the nervous system developing into the nasal cavity around three weeks after birth. ERα appeared during development in the womb as a vestigial response to odorous stimuli such as hair cloy, but it has since been found in the nasal cavity where functional odor neurons are located. In their latest report, the researchers show that ERα acts as a cofactor of neural stem cells that are the precursor cells required to further develop nasal hair cells later in life.

“This discovery is important because ERα regulates many physiological processes in the skin as the forerunner cells in the adult mammalian nervous system. If ERα is missing early in development or is absent in some other disparate developmental zones, then the sense of odor could be severely affected,” says Ming-Hua “Shawn” Zhang, Ph.D., a recent MIT PhD graduate who led the new molecular, cell, and developmental biology team headed by Senior Investigator Michael Gutierrez, Ph.D.

“The ability to detect subtle changes in olfactory sensory function through emergence of unique, dormant neurons in the olfactory system may greatly enhance scientists’ understanding of the total sensory system and serve as a cornerstone of regenerative medicine approaches to treat hearing loss and other hearing disorders,” says Eric C. Moser, who leads the MIT Sloan Center for Regenerative Neuroscience. The true relationship between humans and other mammals in the past remains unclear, but other studies suggest that humans may not be the only species capable of scent differentiation, with several species producing odor molecules expressed by neuroendocrine precursor cells.

In their study, the investigators defined the relative importance of ERα regulation by comparing cells derived from the nasal cavity of bald, deaf, and hearing-immunically-challenged volunteers and cells collected from individuals of the ear and cochlea.