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Histone deacetylase inhibition protects hearing against acute ototoxicity by activating the Nf-κB pathway.

Layman WS, Williams DM, Dearman JA, Sauceda MA, Zuo J - Cell Death Discov (2015)

Bottom Line: We also found that the apparent lack of hair cell loss was completely independent of spontaneous or facilitated (ectopic Atoh1 induction) hair cell regeneration.In addition, we also detected increased expression of pro-survival genes Cdkn1a (p21) and Hspa1a (Hsp70), and decreased expression of the pro-apoptosis gene Bcl2l11 (Bim).These data combined provide evidence that class I HDACs control the transcriptional activation of pro-survival pathways in response to ototoxic insult by regulating the acetylation status of transcription factors found at the crossroads of cell death and survival in the mammalian inner ear.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.

ABSTRACT

Auditory hair cells have repeatedly been shown to be susceptible to ototoxicity from a multitude of drugs including aminoglycoside antibiotics. Here, we found that systemic HDAC inhibition using suberoylanilide hydroxamic acid (SAHA) on adult mice offers almost complete protection against hair cell loss and hearing threshold shifts from acute ototoxic insult from kanamycin potentiated with furosemide. We also found that the apparent lack of hair cell loss was completely independent of spontaneous or facilitated (ectopic Atoh1 induction) hair cell regeneration. Rather, SAHA treatment correlated with RelA acetylation (K310) and subsequent activation of the Nf-κB pro-survival pathway leading to expression of pro-survival genes such as Cflar (cFLIP) and Bcl2l1 (Bcl-xL). In addition, we also detected increased expression of pro-survival genes Cdkn1a (p21) and Hspa1a (Hsp70), and decreased expression of the pro-apoptosis gene Bcl2l11 (Bim). These data combined provide evidence that class I HDACs control the transcriptional activation of pro-survival pathways in response to ototoxic insult by regulating the acetylation status of transcription factors found at the crossroads of cell death and survival in the mammalian inner ear.

No MeSH data available.


Related in: MedlinePlus

SAHA protects against kanamycin ototoxicity. Mice were administered either vehicle (DMSO) or 100 mg/kg SAHA systemically, then treated with vehicle (0.9% saline), 600 mg/kg, 800 mg/kg, or 1000 mg/kg kanamycin potentiated by 400 mg/kg furosemide. Immunofluorescence of whole-mount organ of Corti was performed using antibodies against Prestin (white), Pvalb (green), and Hoechst (blue). (a, b and g) Mice treated with vehicle (DMSO) and 600 mg/kg kanamycin had almost complete loss of outer hair cells, whereas SAHA-treated mice had little to no hair cell loss. (c, d and g) Mice receiving 800 mg/kg kanamycin and SAHA retained ~60% of the outer hair cells compared with complete loss of outer hair cells in vehicle (DMSO) control littermates. (e–g) At 1000 mg /kg kanamycin, all the mice regardless of SAHA treatment lost all their outer hair cells. (h) Schematic diagram depicting the dosing schedule of SAHA and kanamycin. All representative images were taken from the middle turn of the cochlea. Scale bar is 20 μm.
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Figure 2: SAHA protects against kanamycin ototoxicity. Mice were administered either vehicle (DMSO) or 100 mg/kg SAHA systemically, then treated with vehicle (0.9% saline), 600 mg/kg, 800 mg/kg, or 1000 mg/kg kanamycin potentiated by 400 mg/kg furosemide. Immunofluorescence of whole-mount organ of Corti was performed using antibodies against Prestin (white), Pvalb (green), and Hoechst (blue). (a, b and g) Mice treated with vehicle (DMSO) and 600 mg/kg kanamycin had almost complete loss of outer hair cells, whereas SAHA-treated mice had little to no hair cell loss. (c, d and g) Mice receiving 800 mg/kg kanamycin and SAHA retained ~60% of the outer hair cells compared with complete loss of outer hair cells in vehicle (DMSO) control littermates. (e–g) At 1000 mg /kg kanamycin, all the mice regardless of SAHA treatment lost all their outer hair cells. (h) Schematic diagram depicting the dosing schedule of SAHA and kanamycin. All representative images were taken from the middle turn of the cochlea. Scale bar is 20 μm.

Mentions: SAHA and other HDAC inhibitors have repeatedly been shown to have neuroprotective effects in vitro and in vivo on models of inflammation, neurodegeneration, and oxidative stress.1–3,8–10 The formation of reactive oxygen species (ROS) and the induction of inflammatory pathways are the primary causes that underlie the molecular pathology of hair cell death related to ototoxicity.11,12 To determine whether SAHA protects against acute damage from ototoxicity, we used the aminoglycoside antibiotic, kanamycin, in conjunction with furosemide, a loop diuretic also known to cause ototoxicity and facilitate kanamycin crossing the blood–labyrinth barrier in mice. C57BL/6J and FVB/NJ wild-type mice received systemic administration of kanamycin by subcutaneous injection of 600 mg/kg (FVB n = 8; B6 n = 8), 800 mg/kg (FVB n = 8; B6 n = 8), or 1000 mg/kg (FVB n = 8; B6 n = 8) kanamycin dissolved in 0.9% saline in conjunction with intraperitoneal injection of 400 mg/kg furosemide that was given once at P29. We administered 100 mg/kg SAHA (FVB n = 4; B6 n = 4) or vehicle (DMSO; FVB n = 4; B6 n = 4) at P28 (1 day before acute damage), then at P29 (8 h after kanamycin/furosemide treatment), and at P30 (Figure 2h). It is important to note that all vehicle control mice (kanamycin vehicle, 0.9% saline and SAHA vehicle, DMSO) received 400 mg/kg furosemide; as furosemide alone (no kanamycin) combined with SAHA or vehicle had no effect (data not shown), we will only refer to whether kanamycin or SAHA/vehicle were administered. Mice were euthanized at P42, processed for immunofluorescence, and analyzed for morphologic changes to the inner ear, specifically the organ of Corti where the auditory hair cells reside. Mice treated with SAHA and 600 mg/kg kanamycin had little to no hair cell loss compared with DMSO-treated control mice, which had almost complete loss of outer hair cells (Figures 2a, b and g). Mice treated with SAHA and 800 mg/kg kanamycin retained ~ 60% of the outer hair cells (Figures 2c, d and g), whereas mice treated with SAHA and 1000 mg/kg kanamycin lost all outer hair cells (Figures 2e and f). These data together suggest that SAHA protects outer hair cells from kanamycin ototoxicity but very high doses of kanamycin overwhelm SAHA's protective effect.


Histone deacetylase inhibition protects hearing against acute ototoxicity by activating the Nf-κB pathway.

Layman WS, Williams DM, Dearman JA, Sauceda MA, Zuo J - Cell Death Discov (2015)

SAHA protects against kanamycin ototoxicity. Mice were administered either vehicle (DMSO) or 100 mg/kg SAHA systemically, then treated with vehicle (0.9% saline), 600 mg/kg, 800 mg/kg, or 1000 mg/kg kanamycin potentiated by 400 mg/kg furosemide. Immunofluorescence of whole-mount organ of Corti was performed using antibodies against Prestin (white), Pvalb (green), and Hoechst (blue). (a, b and g) Mice treated with vehicle (DMSO) and 600 mg/kg kanamycin had almost complete loss of outer hair cells, whereas SAHA-treated mice had little to no hair cell loss. (c, d and g) Mice receiving 800 mg/kg kanamycin and SAHA retained ~60% of the outer hair cells compared with complete loss of outer hair cells in vehicle (DMSO) control littermates. (e–g) At 1000 mg /kg kanamycin, all the mice regardless of SAHA treatment lost all their outer hair cells. (h) Schematic diagram depicting the dosing schedule of SAHA and kanamycin. All representative images were taken from the middle turn of the cochlea. Scale bar is 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 2: SAHA protects against kanamycin ototoxicity. Mice were administered either vehicle (DMSO) or 100 mg/kg SAHA systemically, then treated with vehicle (0.9% saline), 600 mg/kg, 800 mg/kg, or 1000 mg/kg kanamycin potentiated by 400 mg/kg furosemide. Immunofluorescence of whole-mount organ of Corti was performed using antibodies against Prestin (white), Pvalb (green), and Hoechst (blue). (a, b and g) Mice treated with vehicle (DMSO) and 600 mg/kg kanamycin had almost complete loss of outer hair cells, whereas SAHA-treated mice had little to no hair cell loss. (c, d and g) Mice receiving 800 mg/kg kanamycin and SAHA retained ~60% of the outer hair cells compared with complete loss of outer hair cells in vehicle (DMSO) control littermates. (e–g) At 1000 mg /kg kanamycin, all the mice regardless of SAHA treatment lost all their outer hair cells. (h) Schematic diagram depicting the dosing schedule of SAHA and kanamycin. All representative images were taken from the middle turn of the cochlea. Scale bar is 20 μm.
Mentions: SAHA and other HDAC inhibitors have repeatedly been shown to have neuroprotective effects in vitro and in vivo on models of inflammation, neurodegeneration, and oxidative stress.1–3,8–10 The formation of reactive oxygen species (ROS) and the induction of inflammatory pathways are the primary causes that underlie the molecular pathology of hair cell death related to ototoxicity.11,12 To determine whether SAHA protects against acute damage from ototoxicity, we used the aminoglycoside antibiotic, kanamycin, in conjunction with furosemide, a loop diuretic also known to cause ototoxicity and facilitate kanamycin crossing the blood–labyrinth barrier in mice. C57BL/6J and FVB/NJ wild-type mice received systemic administration of kanamycin by subcutaneous injection of 600 mg/kg (FVB n = 8; B6 n = 8), 800 mg/kg (FVB n = 8; B6 n = 8), or 1000 mg/kg (FVB n = 8; B6 n = 8) kanamycin dissolved in 0.9% saline in conjunction with intraperitoneal injection of 400 mg/kg furosemide that was given once at P29. We administered 100 mg/kg SAHA (FVB n = 4; B6 n = 4) or vehicle (DMSO; FVB n = 4; B6 n = 4) at P28 (1 day before acute damage), then at P29 (8 h after kanamycin/furosemide treatment), and at P30 (Figure 2h). It is important to note that all vehicle control mice (kanamycin vehicle, 0.9% saline and SAHA vehicle, DMSO) received 400 mg/kg furosemide; as furosemide alone (no kanamycin) combined with SAHA or vehicle had no effect (data not shown), we will only refer to whether kanamycin or SAHA/vehicle were administered. Mice were euthanized at P42, processed for immunofluorescence, and analyzed for morphologic changes to the inner ear, specifically the organ of Corti where the auditory hair cells reside. Mice treated with SAHA and 600 mg/kg kanamycin had little to no hair cell loss compared with DMSO-treated control mice, which had almost complete loss of outer hair cells (Figures 2a, b and g). Mice treated with SAHA and 800 mg/kg kanamycin retained ~ 60% of the outer hair cells (Figures 2c, d and g), whereas mice treated with SAHA and 1000 mg/kg kanamycin lost all outer hair cells (Figures 2e and f). These data together suggest that SAHA protects outer hair cells from kanamycin ototoxicity but very high doses of kanamycin overwhelm SAHA's protective effect.

Bottom Line: We also found that the apparent lack of hair cell loss was completely independent of spontaneous or facilitated (ectopic Atoh1 induction) hair cell regeneration.In addition, we also detected increased expression of pro-survival genes Cdkn1a (p21) and Hspa1a (Hsp70), and decreased expression of the pro-apoptosis gene Bcl2l11 (Bim).These data combined provide evidence that class I HDACs control the transcriptional activation of pro-survival pathways in response to ototoxic insult by regulating the acetylation status of transcription factors found at the crossroads of cell death and survival in the mammalian inner ear.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.

ABSTRACT

Auditory hair cells have repeatedly been shown to be susceptible to ototoxicity from a multitude of drugs including aminoglycoside antibiotics. Here, we found that systemic HDAC inhibition using suberoylanilide hydroxamic acid (SAHA) on adult mice offers almost complete protection against hair cell loss and hearing threshold shifts from acute ototoxic insult from kanamycin potentiated with furosemide. We also found that the apparent lack of hair cell loss was completely independent of spontaneous or facilitated (ectopic Atoh1 induction) hair cell regeneration. Rather, SAHA treatment correlated with RelA acetylation (K310) and subsequent activation of the Nf-κB pro-survival pathway leading to expression of pro-survival genes such as Cflar (cFLIP) and Bcl2l1 (Bcl-xL). In addition, we also detected increased expression of pro-survival genes Cdkn1a (p21) and Hspa1a (Hsp70), and decreased expression of the pro-apoptosis gene Bcl2l11 (Bim). These data combined provide evidence that class I HDACs control the transcriptional activation of pro-survival pathways in response to ototoxic insult by regulating the acetylation status of transcription factors found at the crossroads of cell death and survival in the mammalian inner ear.

No MeSH data available.


Related in: MedlinePlus