Proliferation and epithelial–mesenchymal transition (EMT) of lens epithelium cells (LECs) may contribute to anterior subcapsular cataract (ASC) and posterior capsule opacification (PCO), which are important causes of visual impairment. Histone deacetylases (HDACs)-mediated epigenetic mechanism has a central role in controlling cell cycle regulation, cell proliferation and differentiation in a variety of cells and the pathogenesis of some diseases. However, whether HDACs are involved in the regulation of proliferation and EMT in LECs remain unknown. In this study, we evaluated the expression profile of HDAC family (18 genes) and found that class I and II HDACs were upregulated in transforming growth factor β2 (TGFβ2)-induced EMT in human LEC lines SRA01/04 and HLEB3. Tricostatin A (TSA), a class I and II HDAC inhibitor, suppressed the proliferation of LECs by G1 phase cell cycle arrest not only through inhibition of cyclin/CDK complexes and induction of p21 and p27, but also inactivation of the phosphatidylinositol-3-kinase/Akt, p38MAPK and ERK1/2 pathways. Meanwhile, TSA strongly prevented TGFβ2-induced upregulation of fibronectin, collagen type I, collagen type IV, N-cadherin, Snail and Slug. We also demonstrated that the underlying mechanism of TSA affects EMT in LECs through inhibiting the canonical TGFβ/Smad2 and the Jagged/Notch signaling pathways. Finally, we found that TSA completely prevented TGFβ2-induced ASC in the whole lens culture semi-in vivo model. Therefore, this study may provide a new insight into the pathogenesis of ASC and PCO, and suggests that epigenetic treatment with HDAC inhibitors may be a novel therapeutic approach for the prevention and treatment of ASC, PCO and other fibrotic diseases.

Capsulorhexis size is a critical determinant of integrity and transparency in lens regeneration.

Chidamide is a novel histone deacetylase (HDAC) inhibitor that increases the acetylation of histone H3 by inhibiting the activity of HDAC1 and HDAC2. We previously found that treatment of human colon cancer cells with chidamide led to cell apoptosis and cell cycle arrest at G0/1 phase in vitro. The present study extended the observations in vivo and explored the underlying molecular mechanisms. In nude mice bearing human colon cancer LoVo cell xenografts, chidamide alone or in combination with 5-flurouracil (5-Fu) reduced the expression of HDAC1 and HDAC2, accompanied with increased acetylation of histone H3. Chidamide alone inhibited the tumor growth and induce cell apoptosis in tumor-bearing mice. Combined treatment of chidamide with 5-Fu enhanced the anti-tumor activity of 5-Fu. Western blotting analysis showed that chidamide alone or in combination with 5-Fu upregulated the expressions of cleaved Caspase-3 and cleaved poly-ADP (adenosine diphosphate)-ribose polymerase (PARP). In addition, chidamide alone or in combination with 5-Fu increased the p53, phosphorylated-p53 (p-p53), p21 and γH2AX levels, but suppressed cyclin dependent kinase 4 (CDK4) expression in tumor cells. Chidamide alone or in combination with 5-Fu down regulated the expressions of p-AKT, p-mammalian target of rapamycin (mTOR), p-p70S6K, p-Raf, and p44/42 mitogen activated protein kinase (Erk1/2), indicating the blockage of these signaling pathways. The results demonstrated that chidamide alone or in combination with 5-Fu exerted anti-tumor activity in nude mice bearing human colon cancer LoVo cell xenografts, and several signaling pathways might be involved in the chidamide-induced tumor growth inhibition and tumor cell apoptosis.

Left ventricular hypertrophy (LVH) is an independent cardiovascular risk factor; however, the key strategy necessary for LVH regression in hypertensive patients is not clear. A meta-analysis was conducted to study the effect of blood pressure reduction on LVH regression. We explored the relationship between different degrees of systolic blood pressure (SBP)/diastolic blood pressure (DBP) reduction and LVH regression. A total of 17 randomized controlled trials comprising 2196 hypertensive patients (mean age, 56.3 years; 64.1% were men) were identified. Different degrees of SBP and DBP reductions were significantly associated with LVH regression: SBP reduction ≥20  mm  Hg (SBPM20) (weighted mean difference (WMD): 14.35  g  m(-2); 95% confidence interval (CI): 10.44, 18.26; P<0.0001); SBP reduction <20  mm  Hg (SBPL20 group) (WMD: 14.82  g  m(-2); 95% CI: 9.83, 19.8(2); P<0.0001); DBP reduction ≥10  mm  Hg (DBPM10 group) (WMD: 15.17 g m(-2); 95% CI: 11.86, 18.48; P<0.0001); and DBP reduction <10  mm  Hg (DBPL10 group) (WMD: 11.76  g  m(-2); 95% CI: 3.75, 19.76; P=0.004). Significant regression of LVH was found in the DBPM10 group compared with the SBPM20, SBPL20 and DBPL10 groups (P<0.0001). The most significant decrease in LVH was seen in patients with a mean age over 60 years in the DBPM10 group. Moreover, the renin-angiotensin system inhibitor was found to be the most effective antihypertensive drug for LVH regression. This meta-analysis result indicates that proper DBP reduction plays an important role in the regression of echocardiographic LVH in hypertensive patients.