Receptor activator of NF-κB (RANK), known for controlling bone mass, has been recognized for its role in epithelial cell activation of the mammary gland. Because bone and the epidermo-pilosebaceous unit of the skin share a lifelong renewal activity where similar molecular players operate, and because mammary glands and hair follicles are both skin appendages, we have addressed the function of R...

Hair cell regeneration following various mechanical or chemical insults to the inner ear has become the subject of intense scientific research. This article details current concepts relating to this topic, including descriptions of the hair cell precursor population, the ultrastructural properties of the newly regenerated hair cells, and regeneration of hair cells on the vestibular epithelium. ...

The goals of this study were to investigate the effects of hypoxia on cochlear hair cell damage, and to explore the role of sirtuin1 in hypoxia-induced hair cell damage. Cochlear organotypic cultures from postnatal day 4 rats were used in this study. Hypoxia was induced by treating cochlear explants with CoCl2. Cochlear cultures were treated with CoCl2 alone or in combination with the sirtuin1 ...

−Animals have typically been used in efficacy tests, but there are a number of dissimilarities between humans and animals. To overcome the problems associated with animal testing, a model which is reproduced in vitro with longterm culture with cell growth with in vivo activity must be developed. We made a gel-type dermal equivalent (DE) that contained dermal papilla cells (DPCs) or dermal sheat...

The purpose of the present study was to examine the spatio-temporal pattern of cell proliferation in the chick cochlea in response to the sensory hair cell loss induced by a 1.5 kHz pure tone at 120 dB SPL (1 dB = 20 muPa) for 48 h. DNA replication was evaluated with the bromodeoxyuridine (BrdU) pulse-fix technique. One group of birds was given multiple injections of BrdU (50 mg/kg) over a peri...

Notch-mediated lateral inhibition has been reported to regulate auditory hair cell and supporting cell development from common precursors. While the Notch effector genes Hes1, Hes5 and Hey1 are expressed in the developing cochlea, inactivation of either of them causes only mild abnormality, suggesting their functional redundancy. To explore the roles of Hes/Hey genes in cochlear development, we...

HYPOTHESIS The zebrafish lateral line can be used to identify small molecules that protect against cisplatin-induced hair cell death. BACKGROUND Cisplatin is a commonly used chemotherapeutic agent, which causes hearing loss by damaging hair cells of the inner ear. There are currently no FDA-approved pharmacologic strategies for preventing this side effect. The zebrafish lateral line has been ...

The sensory hair cells of the inner ear are exquisitely sensitive to ototoxic insults. Loss of hair cells after exposure to ototoxic agents causes hearing loss. Chemotherapeutic agents such as cisplatin causes hair cell loss. Cisplatin forms DNA mono-adducts as well as intra- and inter-strand DNA crosslinks. DNA cisplatin adducts are repaired through the DNA damage response. The decision betwee...

A major outstanding goal of vestibular neuroscience is to understand the distinctive functional roles of type I and type II hair cells. One important question is whether these two hair cell types differ in bundle structure. To address this, we have developed methods to characterize stereocilia numbers on identified type I and type II hair cells in the utricle of a turtle, Trachemys scripta. Our...

BACKGROUND AND OBJECTIVES A considerable portion of the hair follicle remains attached to plucked hair and can be used for follicle cell culture. In this study we have phenotyped these cells in an attempt to identify the stem cell fraction. Reports in the literature have indicated that this cell population may be positive for cytokeratin (CK) 19. Because stem cells in general need to be protect...