TY - JOUR
T1 - Endothelin-1 mediated induction of extracellular matrix genes in strial marginal cells underlies strial pathology in Alport mice
AU - Meehan, Daniel T.
AU - Delimont, Duane
AU - Dufek, Brianna
AU - Zallocchi, Marisa
AU - Phillips, Grady
AU - Gratton, Michael Anne
AU - Cosgrove, Dominic
N1 - Funding Information:
The authors thank John (Skip) Kennedy for assistance with figure preparation. This work was supported by NIH R01 DK055000 (to DC) and R01 DC015385 (to DC and MAG). Confocal microscopy was conducted at the Integrated Biomedical Imaging Facility, Creighton University, Omaha, NE ( GM103427 , GM110768 , GM103427 of the NIGMS of NIH , and the Creighton University School of Medicine). Structured illumination microscopy was conducted at the Advanced Microscopy Core Facility, UNMC, Omaha, NE. Support for the UNMC Advanced Microscopy Core Facility was provided by the Nebraska Research Initiative , the Fred and Pamela Buffett Cancer Center Support Grant ( P30CA036727 ), and an Institutional Development Award (IDeA) from the NIGMS of the NIH ( P30GM10639 ). Transmission electron microscopy was conducted at the Microscopy and Digital Imaging Core of the Research Center for Auditory and Vestibular Studies at Washington University (P30 DC004665).
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/11/1
Y1 - 2016/11/1
N2 - Alport syndrome, a type IV collagen disorder, manifests as glomerular disease associated with hearing loss with thickening of the glomerular and strial capillary basement membranes (SCBMs). We have identified a role for endothelin-1 (ET-1) activation of endothelin A receptors (ETARs) in glomerular pathogenesis. Here we explore whether ET-1 plays a role in strial pathology. Wild type (WT) and Alport mice were treated with the ETAR antagonist, sitaxentan. The stria vascularis was analyzed for SCBM thickness and for extracellular matrix (ECM) proteins. Additional WT and Alport mice were exposed to noise or hypoxia and the stria analyzed for hypoxia-related and ECM genes. A strial marginal cell line cultured under hypoxic conditions, or stimulated with ET-1 was analyzed for expression of hypoxia-related and ECM transcripts. Noise exposure resulted in significantly elevated ABR thresholds in Alport mice relative to wild type littermates. Alport stria showed elevated expression of collagen α1(IV), laminin α2, and laminin α5 proteins relative to WT. SCBM thickening and elevated ECM protein expression was ameliorated by ETAR blockade. Stria from normoxic Alport mice and hypoxic WT mice showed upregulation of hypoxia-related, ECM, and ET-1 transcripts. Both ET-1 stimulation and hypoxia up-regulated ECM transcripts in cultured marginal cells. We conclude that ET-1 mediated activation of ETARs on strial marginal cells results in elevated expression of ECM genes and thickening of the SCBMs in Alport mice. SCBM thickening results in hypoxic stress further elevating ECM and ET-1 gene expression, exacerbating strial pathology.
AB - Alport syndrome, a type IV collagen disorder, manifests as glomerular disease associated with hearing loss with thickening of the glomerular and strial capillary basement membranes (SCBMs). We have identified a role for endothelin-1 (ET-1) activation of endothelin A receptors (ETARs) in glomerular pathogenesis. Here we explore whether ET-1 plays a role in strial pathology. Wild type (WT) and Alport mice were treated with the ETAR antagonist, sitaxentan. The stria vascularis was analyzed for SCBM thickness and for extracellular matrix (ECM) proteins. Additional WT and Alport mice were exposed to noise or hypoxia and the stria analyzed for hypoxia-related and ECM genes. A strial marginal cell line cultured under hypoxic conditions, or stimulated with ET-1 was analyzed for expression of hypoxia-related and ECM transcripts. Noise exposure resulted in significantly elevated ABR thresholds in Alport mice relative to wild type littermates. Alport stria showed elevated expression of collagen α1(IV), laminin α2, and laminin α5 proteins relative to WT. SCBM thickening and elevated ECM protein expression was ameliorated by ETAR blockade. Stria from normoxic Alport mice and hypoxic WT mice showed upregulation of hypoxia-related, ECM, and ET-1 transcripts. Both ET-1 stimulation and hypoxia up-regulated ECM transcripts in cultured marginal cells. We conclude that ET-1 mediated activation of ETARs on strial marginal cells results in elevated expression of ECM genes and thickening of the SCBMs in Alport mice. SCBM thickening results in hypoxic stress further elevating ECM and ET-1 gene expression, exacerbating strial pathology.
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U2 - 10.1016/j.heares.2016.08.003
DO - 10.1016/j.heares.2016.08.003
M3 - Article
C2 - 27553900
AN - SCOPUS:84984600833
VL - 341
SP - 100
EP - 108
JO - Hearing Research
JF - Hearing Research
SN - 0378-5955
ER -