Investigation of novel PKC targets in the regulation of autophagy

Protein Kinase C (PKC) isozymes are serine/threonine kinases that are important for activation and/or inactivation of intracellular signaling pathways and therefore regulate cellular metabolism. Autophagy is a degradation mechanism functioning under basal conditions and activating under cellular stress including nutrient limitation, oxidative stress or abnormal protein accumulation. It is initiated by formation of double or multi-membrane vesicles in the cytoplasm. These vesicles engulf the cargo and carry it to the lysosome. After the fusion of autophagic vesicle with lysosomes, the cargo is degraded, and its constituents are recycled. The signaling pathways regulated by PKC isozymes are also involved in autophagy mechanism. However, the interaction between autophagy and PKC isozymes is still unclear. The aim of the study is to find novel proteins targeted by PKC isozymes during autophagy mechanism. For this aim, lentiviral shRNA library system was used for silencing of the genes in GFP-LC3 stably expressing mouse embryonic fibroblast (MEF) transgenic cells (MEF GFP-LC3). Upon activation of PKC isozymes, autophagic machinery was examined by GFP-LC3 puncta count, LC3 shift assay and p62 accumulation. Then the positive clones were selected, and their genomic DNA was isolated for target gene sequencing. The genes were identified with Sanger sequence analysis and their relationship with PKC isozymes were analyzed by using RT-q-PCR. Consequently, the role of target gene in the regulation of autophagy was determined by commonly used autophagy techniques

Molecular pathogenesis of nonalcoholic steatohepatitis (NASH)-related hepatocellular carcinoma

The proportion of obese or diabetic population has been anticipated to increase in the upcoming decades, which rises the prevalence of nonalcoholic fatty liver disease (NAFLD) and its advanced form nonalcoholic steatohepatitis (NASH). Recent evidences indicate that, NASH is the main cause of chronic liver diseases and it is an important risk factor for development of hepatocellular carcinoma (HCC). Although the literature addressing NASH-HCC is growing rapidly, limited data is available about the etiology of NASH-related HCC. Experimental studies on the molecular mechanism of HCC development in NASH reveal that the carcinogenesis is relevant to complex changes in signaling pathways that mediate cell proliferation and energy metabolism. Genetic or epigenetic modifications and alterations in metabolic, immunologic and endocrine pathways that have been shown to be closely related to inflammation, liver injury and fibrosis in NASH along with its subsequent progression to HCC. In this review, we provide an overview on the current knowledge in NASH-related HCC development and emphasize molecular signaling pathways regarding to their mechanism of action in NASH-derived HCC

Protein kinase C isozymes and autophagy during neurodegenerative disease progression

Protein kinase C (PKC) isozymes are members of the Serine/Threonine kinase family regulating cellular events following activation of membrane bound phospholipids. The breakdown of the downstream signaling pathways of PKC relates to several disease pathogeneses particularly neurodegeneration. PKC isozymes play a critical role in cell death and survival mechanisms, as well as autophagy. Numerous studies have reported that neurodegenerative disease formation is caused by failure of the autophagy mechanism. This review outlines PKC signaling in autophagy and neurodegenerative disease development and introduces some polyphenols as effectors of PKC isozymes for disease therapy

MnO2 Nanoflower Integrated Optoelectronic Biointerfaces for Photostimulation of Neurons

Abstract Optoelectronic biointerfaces have gained significant interest for wireless and electrical control of neurons. Three–dimentional (3D) pseudocapacitive nanomaterials with large surface areas and interconnected porous structures have great potential for optoelectronic biointerfaces that can fulfill the requirement of high electrode‐electrolyte capacitance to effectively transduce light into stimulating ionic currents. In this study, the integration of 3D manganese dioxide (MnO2) nanoflowers into flexible optoelectronic biointerfaces for safe and efficient photostimulation of neurons is demonstrated. MnO2 nanoflowers are grown via chemical bath deposition on the return electrode, which has a MnO2 seed layer deposited via cyclic voltammetry. They facilitate a high interfacial capacitance (larger than 10 mF cm−2) and photogenerated charge density (over 20 µC cm−2) under low light intensity (1 mW mm−2). MnO2 nanoflowers induce safe capacitive currents with reversible Faradaic reactions and do not cause any toxicity on hippocampal neurons in vitro, making them a promising material for biointerfacing with electrogenic cells. Patch‐clamp electrophysiology is recorded in the whole‐cell configuration of hippocampal neurons, and the optoelectronic biointerfaces trigger repetitive and rapid firing of action potentials in response to light pulse trains. This study points out the potential of electrochemically‐deposited 3D pseudocapacitive nanomaterials as a robust building block for optoelectronic control of neurons