Localization of Laminin Isoforms in the Guinea Pig Cochlea

Weinberger, Debra G.; Cate, Wouter Jan Ten; Lautermann, J.; Baethmann, Martina

doi:10.1097/00005537-199912000-00020

Cited by 8 publications

(7 citation statements)

References 29 publications

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“…This study demonstrates a high degree of conservation of the human cochlea with chinchilla (Tsuprun and Santi, 2001) and guinea pig (Weinberger et al, 1999). A similar distribution of laminin in studies using nonspecific laminin antibodies has been documented in the cochlea of rat (Satoh et al, 1998) and the developing human fetus (Yamashita et al, 1991).…”

Section: Discussionmentioning

confidence: 73%

“…Most of the studies of collagen IV, laminin, and nidogen expression in cochlear BMs have been in rodent species: mouse (Cosgrove et al, 1996; Rodgers et al, 2001; Meyer zum Gottesberge and Felix, 2005), guinea pig (Weinberger et al, 1999; Kalluri et al, 1998; Takahashi and Hokunan, 1992), rat (Satoh et al, 1998) or chinchilla (Tsuprun and Santi, 2001). There are only a few such studies of the vestibular periphery in any mammalian model (Yamashita et al, 1991; Swartz and Santi, 1999), and there are less than a handful of studies that investigate the composition of human cochlear BMs (Zehnder et al, 2005; Yamashita et al, 1991; Kleppel et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

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Immunohistochemical distribution of basement membrane proteins in the human inner ear from older subjects

et al. 2009

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The immunolocalization of several basement membrane (BM) proteins was investigated in vestibular endorgans microdissected from temporal bones obtained from subjects with a documented normal auditory and vestibular function (n = 5, average age = 88 years old). Fluorescent immunostaining using antibodies directed at collagen IVα2, nidogen-1, laminin-β2, α-dystroglycan, and tenascin-C was applied to cryosections from human cochlea, cristae ampullares, utricular and saccular maculae. Collagen IVα2, nidogen-1, and laminin-β2 localized to all subepithelial cochlear BMs, Reissner's membrane, strial and spiral ligamental perineural and perivascular BMs, and the spiral limbus. Tenascin-C localized to the basilar membrane and the osseous spiral lamina. α-dystroglycan localized to most cochlear BMs except those in the spiral ligament, basilar membrane and spiral limbus. Collagen IV, nidogen-1, and laminin-β2 localized to the subepithelial BMs of the maculae and cristae ampullares, and the perineural and perivascular BMs within the underlying stroma. The BM underlying the transitional and dark cell region of the cristae ampullares also expressed collagen IV, nidogen-1, and laminin β2. Tenascin-C localized to the subepithelial BMs of the utricular maculae and cristae ampullares, and to calyx-like profiles throughout the vestibular epithelium, but not to the perineural and perivascular BMs. α-dystroglycan colocalized with aquaporin-4 in the basal vestibular supporting cell, and was also expressed in the subepithelial BMs, as well as perivascular and perineural BMs. This study provides the first comprehensive immunolocalization of these ECM proteins in the human inner ear. The validity of the rodent models for inner ear disorders secondary to BM pathologies was confirmed as there is a high degree of conservation of expression of these proteins in the human inner ear. This information is critical to begin to unravel the role that BMs may play in human inner ear physiology and audiovestibular pathologies.

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Section: Discussionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Immunohistochemical distribution of basement membrane proteins in the human inner ear from older subjects

et al. 2009

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“…BMs mostly show the layer of lamina lucida and lamina densa, however, the vascular BM of the stria vascularis appears as a diffuse layer of lamina densa (Tsupran and Santi 1999). In the past decade laminin, different types of collagen IV, heparan sulfate proteoglycans, entactin/nidogen have been immunolocalized in developing mammalian cochlea and adults (Tokahashi and Hokunan 1992;Cosgrove et al 1996aCosgrove et al , 1996bCosgrove and Rodgers 1997;Weinberger et al 1999;Rodgers et al 2001;Tsupran and Santi 2001).…”

Section: Introductionmentioning

confidence: 99%

Abnormal basement membrane in the inner ear and the kidney of the Mpv17-/- mouse strain: ultrastructural and immunohistochemical investigations

Gottesberge

Felix

2005

Histochem Cell Biol

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The loss of the function of the peroxisomal Mpv17-protein and associated imbalanced radical oxygen species (ROS) homeostasis leads to an early onset of focal segmental glomerulosclerosis and sensorineural deafness associated with severe degeneration of cochlear structures. An excessive enlargement of basal laminae of the stria vascularis capillaries and glomeruli indicates numerous changes in their molecular composition. The basement membrane (BM) of the glomeruli and the stria vascularis are simultaneously affected in early stages of the disease and the lamination, splitting of the membrane and formation of the "basket weaving" seen at the onset of the disease in the kidney are similar to the ultrastructural alterations characteristic for Alporta9s syndrome. The progressive alteration of the BMs is accompanied by irregularity in the distribution of the collagen IV subunits and by an accumulation of the laminin B2(gamma1) in the inner ear and B(beta1) in the kidney. Since Mpv17 protein contributes to ROS homeostasis, further studies are necessary to elucidate downstream signaling molecules activated by ROS. These studies explain the cellular responses to missing Mpv17-protein, such as accumulation of the extracellular matrix, degeneration, and apoptosis in the inner ear.

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“…In accordance with their role in ionic and water transport, fibrocytes express various combinations of ion and water channels, carbonic anhydrases II and III (3,21,25,27,30), as well as gap junction connexins 26, 30, and 31 (7, 12, 37). The findings that fibrocytes also express extracellular matrix proteins (15,33,35) and proteins involved in cell-cell signaling, such as bone and cartilage morphogens (2,18,20,31) and the inner ear-specific cochlin, whose function is unknown (19), indicate a broader role and probably a diversity of specific functions that remain to be elucidated. The fact that the alteration of the fibrocyte integrity leads to pathology is an indication of their importance in inner ear physiology.…”

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confidence: 99%

Deafness and Cochlear Fibrocyte Alterations in Mice Deficient for the Inner Ear Protein Otospiralin

Delprat

Ruel

Guitton

et al. 2005

Molecular and Cellular Biology

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In the cochlea, the mammalian auditory organ, fibrocytes of the mesenchymal nonsensory regions play important roles in cochlear physiology, including the maintenance of ionic and hydric components in the endolymph. Occurrence of human deafness in fibrocyte alterations underlines their critical roles in auditory function. We recently described a novel gene, Otos, which encodes otospiralin, a small protein of unknown function that is produced by the fibrocytes of the cochlea and vestibule. We now have generated mice with deletion of Otos and found that they show moderate deafness, with no frequency predominance. Histopathology revealed a degeneration of type II and IV fibrocytes, while hair cells and stria vascularis appeared normal. Together, these findings suggest that impairment of fibrocytes caused by the loss in otospiralin leads to abnormal cochlear physiology and auditory function. This moderate dysfunction may predispose to age-related hearing loss.Within the cochlea, the mammalian auditory organ, mesenchymal nonsensory regions (i.e., the spiral limbus proximal to the cochlear axis and the spiral ligament forming the lateral wall of the cochlea) contain fibrocytes that play important roles in cochlear physiology. In the spiral ligament, these fibrocytes form distinct groups according to their location, morphological appearance, and marker expression, which suggest their functional specialization (26). Thus, the circumferentially oriented type III fibrocytes lining the otic capsule and the spindleshaped type IV fibrocytes lateral to the basilar membrane package the cochlear content and buffer mechanical constraints generated by sound vibrations (8). The type I fibrocytes (behind the stria vascularis), tightly packed with collagen bundles, shape the curvature of the lateral wall. Type II fibrocytes (below the stria vascularis) and type V fibrocytes (above the stria vascularis) are rich in mitochondria and form many interdigitating processes, indicating high metabolic and exchange activities. Type I, II, and V fibrocytes and basal and intermediate cells of the stria vascularis are all interconnected with gap junctions (10). This gap-junctioned network is postulated to be involved in ion and water circulation, including potassium recycling (34). Potassium is indeed central to the cochlear physiology, since it is the charge-carrying ion for the sensory transduction. It is secreted by the marginal cells of the stria vascularis to maintain a very high concentration (150 mM) in the endolymph, the extracellular fluid bathing hair cell stereocilia. Recycling of potassium though the fibrocyte network is one of several processes that provide potassium to intermediate cells of the stria vascularis (28, 34). This permanent flux of potassium cycling in the cochlea generates the so-called "endocochlear potential " (ϩ85 mV), which gives the main driving force for potassium entry into the sensory hair cell.Progress in the functional characterization of the cochlear fibrocytes has been made with the discovery of proteins exp...

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Localization of Laminin Isoforms in the Guinea Pig Cochlea

Abstract: Anti-laminin antibodies have been found in patients with inner ear disorders. Laminin gamma1 demonstrates specific staining at multiple sites in the guinea pig cochlea. These structures may be targets of antibodies causing sensorineural hearing loss.

Cited by 8 publications

References 29 publications

Immunohistochemical distribution of basement membrane proteins in the human inner ear from older subjects

Immunohistochemical distribution of basement membrane proteins in the human inner ear from older subjects

Abnormal basement membrane in the inner ear and the kidney of the Mpv17-/- mouse strain: ultrastructural and immunohistochemical investigations

Deafness and Cochlear Fibrocyte Alterations in Mice Deficient for the Inner Ear Protein Otospiralin

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