Epidermolysis bullosa simplex (EBS) is a blistering

We have cloned ClC-3B, a novel alternative splicing variant of ClC-3 (ClC-3A) that is expressed predominantly in epithelial cells. ClC-3B has a different, slightly longer C-terminal end than ClC-3A and contains a consensus motif for binding to the second PDZ (PSD95/Dlg/ZO-1) domain of the epithelium-specific scaffolding protein EBP50. Both in vitro and in vivo binding assays demonstrate interaction between ClC-3B and EBP50. C127 mouse mammary epithelial cells transfected with ClC-3B alone showed diffuse immunoreactivity for ClC-3B in the cytoplasmic region. In contrast, when EBP50 was cotransfected with ClC-3B, strong immunoreactivity for ClC-3B appeared at the leading edges of membrane ruffles. Patch-clamp experiments revealed that cotransfection of ClC-3B and EBP50 resulted in a remarkable increase in outwardly rectifying Cl- channel (ORCC) activities at the leading edges of membrane ruffles in C127 cells. The electrophysiological properties of the ClC-3B-induced ORCCs are similar to those of ORCCs described in native epithelial cells. When cystic fibrosis transmembrane conductance regulator (CFTR) was cotransfected with ClC-3B and EBP50, ClC-3B-dependent ORCCs were activated via the protein kinase A-dependent pathway. These findings indicate that ClC-3B is itself a CFTR-regulated ORCC molecule or its activator.

No abstract

Glaucoma is the second leading cause of blindness worldwide and elevated intraocular pressure (IOP) is the most important risk factor. High IOP usually occurs as a result of an increase in aqueous humor outflow resistance at the trabecular meshwork (TM). An abnormal TM contributes to the development of glaucoma. Oxidative stress and vascular damage are considered two major cellular factors that lead to alterations in the TM. In this review, we discuss the findings related to oxidative damage to the TM, including the sources of oxidative stress in the TM such as the mitochondria, peroxisomes, endoplasmic reticulum, membrane, cytosol and exogenous factors. We also discuss antioxidants and clinical studies related to protection against oxidative stress in the TM. Although many questions remain unanswered, it is becoming increasingly clear that oxidative stress-induced damage to the TM is related to glaucoma. This may inspire new studies to find better and more stable antioxidants, and better models with which to elucidate the mechanisms involved, and to determine whether in vitro findings translate into in vivo observations. The regulation of the oxidative/redox balance may be the ultimate target for protecting the TM from oxidative stress and preventing glaucoma.

Liver regeneration has important clinical importance in the setting of partial hepatectomy (PH). Following PH, quiescent hepatocytes can reenter cell cycle to restore liver mass. Hepatocyte cell cycle progression, as the basic motivations of liver regeneration, can be disrupted by multiple pathological factors such as oxidative stress. This study aimed to evaluate the role of advanced oxidation protein products (AOPP) in S-phase arrest in hepatocytes. Serum AOPP level were measured during the perioperative period of PH in 33 patients with hepatocellular carcinoma (HCC). Normal Sprague Dawley rats, human and murine liver cell line (HL-7702 and AML-12) were challenged with AOPP prepared by incubation of rat serum albumin (RSA) with hypochlorous acid, and the effect of AOPP on hepatocytes cell cycle progression and liver regeneration was studied after PH. AOPP levels were increased following partial hepatectomy (PH) in patients with primary liver cancer. AOPP treatment impaired liver regeneration in rats following 70% partial hepatectomy. S-phase arrest was induced by AOPP administration in hepatocytes derived from the remnant liver at controlled times following partial hepatectomy in rats, and in HL-7702 and AML-12 cells. The effect of AOPP on hepatocyte S phase arrest was mainly mediated by a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) generation, downregulation of downstream β-catenin signaling and decreased cyclin-dependent kinase 2 (CDK2) expression, which inhibited S-phase progression in hepatocytes. This study provides preliminary evidence that AOPP can induce S-phase arrest in hepatocytes via the ROS-dependent, β-catenin-CDK2-mediated pathway. These findings suggest a novel pathogenic role of AOPP contributing to the impaired liver regeneration and may provide the basis for developing new strategies to improve liver regeneration in patients undergoing PH.