Closure of supporting cell scar formations requires dynamic actin mechanisms.
In many vertebrate inner ear sensory epithelia, dying sensory hair cells are extruded, and the apices of surrounding supporting cells converge to re-seal the epithelial barrier between the electrochemically-distinct endolymph and perilymph. These cellular mechanisms remain poorly understood. Dynamic microtubular mechanisms have been proposed for hair cell extrusion; while contractile actomyosin-based mechanisms are required for cellular extrusion and closure in epithelial monolayers. The hypothesis that cytoskeletal mechanisms are required for hair cell extrusion and supporting cell scar formation was tested using bullfrog saccules incubated with gentamicin (6h), and allowed to recover (18h). Explants were then fixed, labeled for actin and cytokeratins, and viewed with confocal microscopy. To block dynamic cytoskeletal processes, disruption agents for microtubules (colchicine, paclitaxel) myosin (Y-27632, ML-9) or actin (cytochalasin D, latrunculin A) were added during treatment and recovery. Microtubule disruption agents had no effect on hair cell extrusion or supporting cell scar formation. Myosin disruption agents appeared to slow down scar formation but not hair cell extrusion. Actin disruption agents blocked scar formation, and largely prevented hair cell extrusion. These data suggest that actin-based cytoskeletal processes are required for hair cell extrusion and supporting cell scar formation in bullfrog saccules.
Hordichok
Andrew J
AJ
Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
Steyger
Peter S
PS
D000199:Actins / Q000378:metabolism*; D000577:Amides / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity; D001381:Azepines / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D016923:Cell Death; D002921:Cicatrix / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D003078:Colchicine / Q000494:pharmacology; D015638:Cytochalasin D / Q000494:pharmacology; D005839:Gentamicins / Q000633:toxicity; D006198:Hair Cells, Auditory / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D009218:Myosins / Q000378:metabolism; D017239:Paclitaxel / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011892:Rana catesbeiana; D012444:Saccule and Utricle / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology / Q000648:ultrastructure; D053778:Thiazolidines / Q000494:pharmacology; D013997:Time Factors; D046509:Tissue Culture Techniques; D050257:Tubulin Modulators / Q000494:pharmacology*; D014945:Wound Healing / Q000187:drug effects*
D000199:Actins; D000577:Amides; D000900:Anti-Bacterial Agents; D001381:Azepines; D019086:Bridged Bicyclo Compounds, Heterocyclic; D005839:Gentamicins; D011725:Pyridines; D053778:Thiazolidines; D050257:Tubulin Modulators; C056218:ML 9; C108830:Y 27632; D015638:Cytochalasin D; D007633:Keratins; D009218:Myosins; D017239:Paclitaxel; D003078:Colchicine; C037067:latrunculin A
J Comp Neurol. 2006 Dec 10;499(5):691-701
17048225
Ann N Y Acad Sci. 1996 Jun 19;781:59-70
8694449
Hear Res. 2007 Jun;228(1-2):95-104
17400411
Proc Natl Acad Sci U S A. 2000 Apr 25;97(9):4908-13
10758152
Ann N Y Acad Sci. 1999 Nov 28;884:15-8
10842580
Nat Cell Biol. 2000 Jun;2(6):376-8
10854330
J Anat. 2001 Jan;198(Pt 1):103-16
11215761
Traffic. 2001 Jun;2(6):414-27
11389769
Curr Biol. 2001 Nov 27;11(23):1847-57
11728307
J Neurosci. 2001 Dec 15;21(24):9757-69
11739584
Curr Biol. 2002 Jan 8;12(1):R12-4
11790316
J Neurobiol. 2002 Feb 5;50(2):81-92
11793356
J Neurosci. 2002 Apr 1;22(7):2607-16
11923426
J Biol Chem. 2002 May 3;277(18):15309-16
11839765
J Cell Biochem. 2002;85(4):670-7
11968007
Exp Cell Res. 2002 Jul 15;277(2):161-72
12083798
Mol Genet Metab. 2002 Jul;76(3):217-24
12126936
Neuropharmacology. 2002 Jun;42(8):1109-18
12128012
Nat Cell Biol. 2003 Jul;5(7):599-609
12833063
Curr Biol. 2003 Jul 1;13(13):1096-105
12842008
Proc Natl Acad Sci U S A. 2003 Nov 11;100(23):13495-500
14593207
J Cell Biol. 2004 Mar 15;164(6):887-97
15024034
J Embryol Exp Morphol. 1970 Nov;24(3):625-40
4923996
Clin Nephrol. 1978 Oct;10(4):140-5
719967
J Biol Chem. 1979 Oct 25;254(20):9982-5
489616
Nature. 1981 Sep 24;293(5830):302-5
7196996
J Biol Chem. 1981 Oct 25;256(20):10435-41
6116707
Cell. 1982 Nov;31(1):11-24
6186379
J Biol Chem. 1983 Apr 10;258(7):4190-4
6833250
EMBO J. 1982;1(11):1429-37
6202509
Hear Res. 1985;19(2):171-82
4055536
Invasion Metastasis. 1986;6(1):33-43
2867063
J Invest Dermatol. 1986 Oct;87(4):466-71
2428883
Virchows Arch B Cell Pathol Incl Mol Pathol. 1986;51(6):475-85
2878521
FEBS Lett. 1987 Mar 23;213(2):316-8
3556584
Differentiation. 1987;35(2):151-62
2450800
Hear Res. 1990 Jun;46(1-2):29-40
2380125
Cell Motil Cytoskeleton. 1991;18(3):215-27
1711932
J Neurocytol. 1992 Sep;21(9):663-71
1403011
J Comp Neurol. 1993 Apr 22;330(4):521-32
8320342
Hear Res. 1994 Sep;79(1-2):26-38
7528737
J Cell Physiol. 1995 Apr;163(1):105-14
7896886
J Comp Neurol. 1995 May 8;355(3):405-17
7636022
Curr Biol. 1995 Aug 1;5(8):900-8
7583148
J Neurosci. 1996 Oct 1;16(19):6157-74
8815898
Int J Dev Neurosci. 1997 Jul;15(4-5):417-32
9263023
Mol Cells. 1997 Jun 30;7(3):431-7
9264034
J Cell Biol. 1997 Sep 22;138(6):1379-94
9298992
Hear Res. 1997 Sep;111(1-2):177-84
9307323
Hear Res. 1997 Nov;113(1-2):14-28
9387983
J Biol Chem. 1997 Dec 26;272(52):33197-203
9407108
Hear Res. 1997 Dec;114(1-2):117-26
9447926
J Neurosci. 1998 Jun 15;18(12):4603-15
9614235
Eur J Cell Biol. 1998 Oct;77(2):100-10
9840459
Curr Biol. 1999 Jun 3;9(11):579-87
10359696
Am J Physiol. 1999 Jul;277(1 Pt 2):H100-6
10409187
J Pathol. 1999 Apr;187(5):567-72
10398123
Science. 1999 Aug 27;285(5432):1363-4
10490411
Science. 1964 Jun 26;144(3626):1578-80
14169344
Acta Otolaryngol. 1964 Jun;57:581-98
14181104
Am J Physiol Cell Physiol. 2005 Jun;288(6):C1332-41
15689412
Cell Death Differ. 2006 Jan;13(1):20-30
16021180
J Neurosci Res. 2006 Jun;83(8):1544-51
16521128
J Cell Sci. 2006 Jun 1;119(Pt 11):2269-81
16723733
Hear Res. 2006 Aug;218(1-2):20-9
16777363