Aquaporin 4 expression in the mammalian inner ear and its role in hearing

Mhatre, Anand N.; Stern, Ryan E.; Li, Jiang; Lalwani, Anil K.

doi:10.1016/s0006-291x(02)02296-9

Cited by 65 publications

(43 citation statements)

References 31 publications

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“…The inner ear contains several types of supporting cells. Some of these cell types contain AQP4, while others do not (66,103,105,108,181). As in the retina, the distribution of AQP4 is consistent with an indirect role in K ϩ clearance.…”

Section: B Inner Earsupporting

confidence: 54%

Physiological Roles of Aquaporin-4 in Brain

Nagelhus

Ottersen

2013

Physiological Reviews

553

520

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(AQP4) is one of the most abundant molecules in the brain and is particularly prevalent in astrocytic membranes at the blood-brain and brain-liquor interfaces. While AQP4 has been implicated in a number of pathophysiological processes, its role in brain physiology has remained elusive. Only recently has evidence accumulated to suggest that AQP4 is involved in such diverse functions as regulation of extracellular space volume, potassium buffering, cerebrospinal fluid circulation, interstitial fluid resorption, waste clearance, neuroinflammation, osmosensation, cell migration, and Ca 2ϩ signaling. AQP4 is also required for normal function of the retina, inner ear, and olfactory system. A review will be provided of the physiological roles of AQP4 in brain and of the growing list of data that emphasize the polarized nature of astrocytes.

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Section: B Inner Earsupporting

confidence: 54%

Physiological Roles of Aquaporin-4 in Brain

Nagelhus

Ottersen

2013

Physiological Reviews

553

520

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“…Elimination of ER-b could, therefore, be expected to be accompanied by a loss of or decrease in expression of multiple genes involved in hearing. Mutations in structural genes such as myosin (Donaudy et al 2003, Kudo et al 2003, usherin (Eudy et al 1998, Pennings et al 2002, and aquaporin (Mhatre et al 2002) also result in deafness. -a, and (B) shows that the organ of Corti is missing, resulting in a flat epithelium (red circle).…”

Section: Discussionmentioning

confidence: 99%

Inner ear pathology and loss of hearing in estrogen receptor-β deficient mice

Simonoska¹,

Stenberg²,

Duan

et al. 2009

Journal of Endocrinology

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There are well known differences between males and females in hearing. In the present study, the role of estrogen receptor-b (ER-b; listed as ESR2 in the MGI Database) in hearing was investigated by comparing hearing and morphology of the inner ear in ER-b knock-out mice (ER-b) with that of wild-type (WT) littermates. Hearing was analyzed with auditory brainstem response audiometry at 3 and 12 months. The ER-b K/K mice were deaf at 1 year of age, and the morphological analysis showed absence of hair cells and loss of the whole organ of Corti initiated in the basal turn of the cochlea. Furthermore, in ER-b, but not in WT mice, the spiral ganglion was lacking many of its neurons.Immunostaining showed the presence of both ER-a (listed as ESR1 in the MGI Database) and ER-b in the nuclei of some neurons in the inner ear in WT mice, but no ER-b was found in the ER-b K/K mice as expected. ER-a staining was predominant in the nuclei of large neurons and ER-b in nuclei of small neurons and fibroblasts. These results reveal that both ERs are present in the inner ear at specific localizations suggesting subtype-specific functions. It is concluded that ER-b is important for the prevention of agerelated hearing loss. These findings strengthen the hypothesis that estrogen has a direct effect on hearing functions.

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“…Induction of adipocyte AQP7 expression and/or function might therefore reduce fat mass in some forms of obesity. (Binder et al, 2004a), and reduced evoked potential responses to light (Da and Verkman, 2004;Li et al, 2002) and acoustic (Li and Verkman, 2001;Mhatre et al, 2002) stimuli. Mice lacking α-syntrophin, which exhibit altered AQP4 localization, show reduced extracellular K + clearance following evoked neuronal activity and a greater severity of hyperthermia-induced seizures (Amiry-Moghaddam et al, 2003).…”

Section: Epidermal Hydration and Biosynthesismentioning

confidence: 99%

More than just water channels: unexpected cellular roles of aquaporins

Verkman

2005

Journal of Cell Science

535

449

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Aquaporins (AQPs) are membrane proteins that transport water and, in some cases, also small solutes such as glycerol. AQPs are expressed in many fluid-transporting tissues, such as kidney tubules and glandular epithelia, as well as in non-fluid-transporting tissues, such as epidermis, adipose tissue and astroglia. Their classical role in facilitating trans-epithelial fluid transport is well understood, as in the urinary concentrating mechanism and gland fluid secretion. AQPs are also involved in swelling of tissues under stress, as in the injured cornea and the brain in stroke, tumor and infection. Recent analysis of AQP-knockout mice has revealed unexpected cellular roles of AQPs. AQPs facilitate cell migration, as manifested by reduced tumor angiogenesis in AQP1-knockout mice, by a mechanism that might involve facilitated water transport in lamellipodia of migrating cells. AQPs that transport both glycerol and water regulate glycerol content in epidermis and fat, and consequently skin hydration/biosynthesis and fat metabolism. AQPs might also be involved in neural signal transduction, cell volume regulation and organellar physiology. The many roles of AQPs could be exploited for clinical benefit; for example, treatments that modulate AQP expression/function could be used as diuretics, and in the treatment of brain swelling, glaucoma, epilepsy, obesity and cancer.

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Aquaporin 4 expression in the mammalian inner ear and its role in hearing

Cited by 65 publications

References 31 publications

Physiological Roles of Aquaporin-4 in Brain

Physiological Roles of Aquaporin-4 in Brain

Inner ear pathology and loss of hearing in estrogen receptor-β deficient mice

More than just water channels: unexpected cellular roles of aquaporins

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