Differences in Endolymphatic Sac Mitochondria‐Rich Cells Indicate Specific Functions

Peters, Theo; Tonnaer, E.L.G.M.; Kuijpers, W.; Cremers, C.W.R.J.; Curfs, J.H.A.J.

doi:10.1097/00005537-200203000-00023

Cited by 24 publications

(21 citation statements)

References 34 publications

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“…Thus, TRPV4 would be a likely candidate for mediating regulatory volume decrease in the mitochondria-rich cells. Since the mitochondria-rich cells in the endolymphatic sac are suggested to have several ion channels and transporters, such as pendrin or vascular H + -ATPase [Peters et al, 2002;Dou et al, 2004], they may play an important role in ion and pH regulation of the endolymph. In addition to the above ion channels and pumps, it is assumed that mitochondria-rich cells maintain proper cell functioning using TRPV4 to respond to osmolarity changes and to regulate cell volume.…”

Section: Discussionmentioning

confidence: 99%

Expression of the Osmotically Responsive Cationic Channel TRPV4 in the Endolymphatic Sac

et al. 2008

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The immunohistochemical expression pattern and the physiological role of transient receptor potential vanilloid (TRPV) 4 in the endolymphatic sac were investigated. TRPV4 was expressed predominantly in the apical membrane of mitochondria-rich cells, and cell volume regulation by TRPV4 was observed in a tissue culture of the rat endolymphatic sac. TRPV4 was also present in the endolymphatic sacs of patients with vestibular schwannoma and with Ménière’s disease. TRPV4 is assumed to play a role as an osmoreceptor in cell and fluid volume regulation in the human endolymphatic sac.

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Section: Discussionmentioning

confidence: 99%

Expression of the Osmotically Responsive Cationic Channel TRPV4 in the Endolymphatic Sac

et al. 2008

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“…Perhaps the function of pendrin in the endolymphatic sac is to maintain the ionic and/or pH homeostasis between these two compositionally distinct fluids. It is interesting to note that there are ultrastructural similarities between the epithelia of the renal collecting duct [where pendrin is involved in bicarbonate transport ] and the inner-ear endolymphatic sac (Dahlmann and von During 1995;Peters et al 2002).…”

Section: Discussionmentioning

confidence: 99%

Localization and Functional Studies of Pendrin in the Mouse Inner Ear Provide Insight About the Etiology of Deafness in Pendred Syndrome

Royaux

Belyantseva

et al. 2003

JARO - Journal of the Association for Research in Otolaryngolog

140

149

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Immunolocalization studies of mouse cochlea and vestibular end-organ were performed to study the expression pattern of pendrin, the protein encoded by the Pendred syndrome gene (PDS), in the inner ear. The protein was restricted to the areas composed of specialized epithelial cells thought to play a key role in regulating the composition and resorption of endolymph. In the cochlea, pendrin was abundant in the apical membrane of cells in the spiral prominence and outer sulcus cells (along with their root processes). In the vestibular end-organ, pendrin was found in the transitional cells of the cristae ampullaris, utriculi, and sacculi as well as in the apical membrane of cells in the endolymphatic sac. Pdsknockout (Pds )/) ) mice were found to lack pendrin immunoreactivity in all of these locations. Histological studies revealed that the stria vascularis in Pds )/) mice was only two-thirds the thickness seen in wildtype mice, with the strial marginal cells showing irregular shapes and sizes. Functional studies were also performed to examine the role of pendrin in endolymph homeostasis. Using double-barreled electrodes placed in both the cochlea and the utricle, the endocochlear potential and endolymph potassium concentration were measured in wild-type and Pdsmice. Consistent with the altered strial morphology, the endocochlear potential in Pds )/) mice was near zero and did not change during anoxia. On the other hand, the endolymphatic potassium concentration in Pds )/) mice was near normal in the cochlea and utricle. Together, these results suggest that pendrin serves a key role in the functioning of the basal and/ or intermediate cells of the stria vascularis to maintain the endocochlear potential, but not in the potassium secretory function of the marginal cells.

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“…The endolymphatic sac of the ear contains mitochondria-rich, type A-like cells that express the H-ATPase on the apical plasma membrane and type B-like cells that express pendrin on the apical plasma membrane. 34 Thus, cells of the endolymphatic sac resemble renal intercalated cells both ultrastructurally and functionally. 34 It is likely that with 7 days of DOCP treatment, the cumulative excretion of NaCl and net acid differ in Pds (ϩ/ϩ) and (-/-) mice.…”

Section: Verlander Et Al Mineralocorticoids Upregulate Pendrin In Moumentioning

confidence: 99%

“…34 Thus, cells of the endolymphatic sac resemble renal intercalated cells both ultrastructurally and functionally. 34 It is likely that with 7 days of DOCP treatment, the cumulative excretion of NaCl and net acid differ in Pds (ϩ/ϩ) and (-/-) mice. However, because 24-hour urinary NaCl and net acid excretion did not differ between the 2 groups of mice after 7 days of DOCP treatment, differences in excretion most likely occurred within the first 6 days of DOCP administration.…”

Section: Verlander Et Al Mineralocorticoids Upregulate Pendrin In Moumentioning

confidence: 99%

Deoxycorticosterone Upregulates PDS ( Slc26a4 ) in Mouse Kidney

et al. 2003

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Abstract-Pendrin is an anion exchanger expressed along the apical plasma membrane and apical cytoplasmic vesicles of type B and of non-A, non-B intercalated cells of the distal convoluted tubule, connecting tubule, and cortical collecting duct. Thus, Pds (Slc26a4) is a candidate gene for the putative apical anion-exchange process of the type B intercalated cell. Because apical anion exchange-mediated transport is upregulated with deoxycorticosterone pivalate (DOCP), we tested whether Pds mRNA and protein expression in mouse kidney were upregulated after administration of this aldosterone analogue by using quantitative real-time polymerase chain reaction as well as light and electron microscopic immunolocalization. In kidneys from DOCP-treated mice, Pds mRNA increased 60%, whereas pendrin protein expression in the apical plasma membrane increased 2-fold in non-A, non-B intercalated cells and increased 6-fold in type B cells. Because pendrin transports HCO 3 -and Cl -, we tested whether DOCP treatment unmasks abnormalities in acid-base or NaCl balance in Pds (-/-) mice. In the absence of DOCP, arterial pH, systolic blood pressure, and body weight were similar in Pds (ϩ/ϩ) and Pds (-/-) mice. After DOCP treatment, weight gain and hypertension were observed in Pds (ϩ/ϩ) but not in Pds (-/-) mice. Moreover, after DOCP administration, metabolic alkalosis was more severe in Pds (-/-) than Pds (ϩ/ϩ) mice. We conclude that pendrin is upregulated with aldosterone analogues and is critical in the pathogenesis of mineralocorticoid-induced hypertension and metabolic alkalosis.

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Differences in Endolymphatic Sac Mitochondria‐Rich Cells Indicate Specific Functions

Cited by 24 publications

References 34 publications

Expression of the Osmotically Responsive Cationic Channel TRPV4 in the Endolymphatic Sac

Expression of the Osmotically Responsive Cationic Channel TRPV4 in the Endolymphatic Sac

Localization and Functional Studies of Pendrin in the Mouse Inner Ear Provide Insight About the Etiology of Deafness in Pendred Syndrome

Deoxycorticosterone Upregulates PDS ( Slc26a4 ) in Mouse Kidney

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