Sirt3 Regulates Proliferation and Progesterone Production in Leydig Cells via Suppression of Reactive Oxygen Species.

Sirt3 is a mitochondrial protein deacetylase functioning in energy metabolism, regulation of intracellular reactive oxygen species (ROS) levels, and aging. Although Sirt3 loss has negative effects on fertility of oocytes during in vitro fertilization and on progesterone production in granulosa cells, Sirt3's function in Leydig cells remains unclear. Therefore, we investigated Sirt3 activity in Leydig cells, focusing on androgen production. To do so, we performed immunohistochemistry to confirm Sirt3 localization in gonads and observed strong Sirt3 immunostaining in Leydig cells of human testes and of Sirt3+/+ and Sirt3+/- mouse testes, while Sirt3-/- mouse testis tissue was negative. In human ovary, hilus cells were strongly Sirt3-positive, theca cells showed weak positivity, and granulosa cells showed very weak or almost no immunostaining. Next, we used the murine Leydig tumor cell line MA-10 as a model. We overexpressed Sirt3 but observed no changes in proliferation, expression of Star, Cyp11a1 (p450scc gene), and Hsd3b, or progesterone production in MA-10 cells. Sirt3 knockdown significantly reduced proliferation, suppressed expressions of steroidogenic enzymes and of transcription factors Ad4bp (Sf-1 gene) and Gata4, and decreased progesterone production. Sirt3 knockdown in MA-10 cells also increased intracellular ROS levels based on CM-H2DCFDA fluorescence dye analysis and increased the proportion of both early and late apoptotic (necrotic) cells based on Annexin V/7AAD assays. These results indicate that Sirt3 has a potential function in androgen production in Leydig cells by regulating intracellular ROS levels.

Multistep, site-selective noncovalent synthesis of two-dimensional block supramolecular polymers.

Although the principles of noncovalent bonding are well understood and form the basis for the syntheses of many intricate supramolecular structures, supramolecular noncovalent synthesis cannot yet achieve the levels of precision and complexity that are attainable in organic and/or macromolecular covalent synthesis. Here we show the stepwise synthesis of block supramolecular polymers from metal-porphyrin derivatives (in which the metal centre is Zn, Cu or Ni) functionalized with fluorinated alkyl chains. These monomers first undergo a one-dimensional supramolecular polymerization and cyclization process to form a toroidal structure. Subsequently, successive secondary nucleation, elongation and cyclization steps result in two-dimensional assemblies with concentric toroidal morphologies. The site selectivity endowed by the fluorinated chains, reminiscent of regioselectivity in covalent synthesis, enables the precise control of the compositions and sequences of the supramolecular structures, as demonstrated by the synthesis of several triblock supramolecular terpolymers.

The relationship between acrolein and oxidative stress in COPD: in systemic plasma and in local lung tissue.

Purpose: Cigarette smoke produces a high level of acrolein, which is thought to be pathogenically involved in the development of chronic obstructive pulmonary disease (COPD). The present study investigated the pathological role of acrolein in the development of COPD. Patients and methods: Acrolein concentration was measured in plasmas obtained from 47 patients with COPD and 18 current smokers without COPD, and in supernatants of homogenized lung tissues obtained from 10 never-smokers, 8 current smokers, and 8 patients with COPD by high-performance liquid chromatography. Oxidant status and antioxidant activity were measured using derivatives of reactive oxygen metabolite (d-ROM) and bio-antioxidant power (BAP), respectively, in the Free Radical Elective Evaluation FRAS4 system. In addition, immunohistochemistry was used to evaluate the over-presentation of acrolein in lung tissues of patients with COPD. Results: Plasma concentrations of acrolein were significantly higher in the patients with COPD than the non-COPD smokers (P<0.001), which significantly correlated with the oxidant status in patients with COPD (R=0.69, P<0.05). Similar pathological alterations in acrolein concentrations were found in the lung tissue supernatants of patients with COPD, which significantly correlated with the oxidant status in patients with COPD. Furthermore, acrolein was strongly expressed in the lung tissues of patients with COPD. Conclusion: The increased acrolein concentrations were highly involved in the pathogenesis of COPD through interference in the balance of oxidative stress versus antioxidant potentiality.

L-carbocisteine reduces neutrophil elastase-induced mucin production.

Human neutrophil elastase (HNE) exists in high concentrations in airway secretions and produces mucus hypersecretion in patients with chronic obstructive pulmonary disease (COPD). L-carbocisteine improves the quality of life and reduces exacerbation in COPD patients. However the precise mechanism is uncertain. We examined the effects of L-carbocisteine on HNE-induced mucus hypersecretion and on the production of reactive oxygen species (ROS) which is associated with mucin production induced by HNE. NCI-H292, a human lung mucoepidermoid carcinoma cell line, was treated with or without HNE and L-carbocisteine. MUC5AC mRNA expression and ROS production in the cells, and MUC5AC protein concentration in supernatants were measured. HNE increased MUC5AC mRNA expression and MUC5AC protein concentration in supernatants in the cells. L-carbocisteine reduces HNE-induced mRNA expression and protein secretion of MUC5AC. L-carbocisteine also reduced ROS production in the cells induced by HNE. Reduction of HNE-induced mucus secretion by L-carbocisteine in the pulmonary epithelial cells may partly relate to the reduction of ROS.