Dysregulation of histone deacetylase and histone acetyltransferase in development of Wegener's granulomatosis

Piceatannol Attenuates Renal Fibrosis Induced by Unilateral Ureteral Obstruction via Downregulation of Histone Deacetylase 4/5 or p38-MAPK Signaling

Piceatannol, a resveratrol metabolite, is a phenolic compound found in red wine and grapes. We investigated the effect of piceatannol on renal fibrosis and histone deacetylase (HDAC) expression in a mouse model of unilateral ureteral obstruction (UUO). Fibrosis was established by UUO and piceatannol was intraperitoneally injected for 2 weeks. Piceatannol suppressed extracellular matrix (ECM) protein deposition including collagen type I and fibronectin as well as connective tissue growth factor (CTGF) and α-smooth muscle actin (α-SMA) in UUO kidneys. However, the expressions of epithelial-mesenchymal transition (EMT) marker genes, such as N-cadherin and E-cadherin, were not changed in the kidneys after UUO. Masson’s trichrome staining and fluorescence immunostaining showed that piceatannol administration attenuated collagen deposition in UUO kidneys. HDAC1, HDAC4, HDAC5, HDAC6, and HDAC10 protein expression was upregulated in UUO kidneys, whereas that of HDAC8 was downregulated. Piceatannol treatment significantly reduced HDAC4 and HDAC5 protein expression. Further, piceatannol attenuated phosphorylation of p38 mitogen-activated protein kinase (p38-MAPK) in UUO kidneys, but not that of transforming growth factor beta1-Smad2/3. These results suggest that class I HDACs and class IIa/b HDACs are involved in renal fibrosis development. Piceatannol may be a beneficial therapeutic agent for treating renal fibrosis via reduction of HDAC4 and HDAC5 protein expression or suppression of the p38-MAPK signaling pathway.

Histone Deacetylase 2 in Sudden Sensorineural Hearing Loss Patients in Response to Intratympanic Methylprednisolone Perfusion

OBJECTIVE

To evaluate the expression of histone deacetylase 2 (HDAC2) in peripheral blood mononuclear cells (PBMCs) from patients with sudden sensorineural hearing loss (SSNHL) who were refractory to systemic glucocorticoid treatment and to identify the relationship between the level of HDAC2 and glucocorticoid insensitivity.

STUDY DESIGN

Prospective clinical study.

SETTING

This study was conducted in Nanjing Drum Tower Hospital, Nanjing University Medical School.

SUBJECTS AND METHODS

PBMCs were collected from 42 refractory SSNHL patients. After a 10-day intratympanic methylprednisolone perfusion (IMP) and systemic Ginkgo biloba extract treatment, the SSNHL patients were divided into 2 groups according to their hearing recovery after IMP (IMP sensitive and insensitive). Real-time polymerase chain reaction and HDAC2 protein assays were used to detect the relative expression levels of HDAC2 in PBMCs. The HDAC2 mRNA expression and protein levels in PBMCs collected from 17 volunteers were used as normal HDAC2 reference levels.

RESULTS

Compared with normal reference levels, HDAC2 protein levels were significantly reduced, while the HDAC2 mRNA expression was much higher in all refractory SSNHL patients before IMP. HDAC2 mRNA expression and HDAC2 protein levels were significantly elevated in the IMP-sensitive group, while no change was observed in the IMP-insensitive group after IMP plus systemic antioxidant treatment.

CONCLUSIONS

Reduced HDAC2 protein levels may be 1 of the mechanistic underpinnings of corticosteroid insensitivity in refractory SSNHL patients. IMP can increase HDAC2 protein levels and the expression of HDAC2 mRNA in IMP-sensitive patients. HDAC2 protein levels might be regulated through posttranslational modifications.