Regulation of Rat Hepatocyte Protein Kinase C β Isoenzymes by the Lipid Peroxidation Product 4–Hydroxy–2,3–Nonenal: A Signaling Pathway to Modulate Vesicular Transport of Glycoproteins

Abstract

A major aldehydic end product of the peroxidation of arachidonic acid, 4-hydroxy-2,3-nonenal (HNE), has recently been considered for its potential involvement in a variety of cell functions. Here we report on the differential regulation of rat hepatocyte protein kinase C (PKC) isoforms by concentrations of HNE actually detectable in specific biological fluids or tissues. PKC ␤I and, to a much greater extent, PKC ␤II activities were markedly increased by 0.1 mol/L HNE (final concentration in cell medium) whereas they were unaffected or even inhibited by 1 to 10 mol/L HNE. On the contrary, the calcium independent PKC ␦ activity was inhibited by 0.1 mol/L and increased by 1 and 10 mol/L. The carbonyl compound 4-hydroxy-2,3-nonenal (HNE) is one of the major products of the oxidative breakdown of -6 fatty acids, the featuring process of membrane lipid peroxidation. 1 This aldehyde, being strongly electrophylic, readily reacts at neutral or slightly alkaline pH with sulphydryl and amino groups. HNE production was quantified several years ago in rat liver microsomes and isolated hepatocytes undergoing various experimental conditions of enhanced lipid peroxidation. 2,3 In more recent in vivo experimental reproduction of liver 4 and arterial 5,6 fibrosclerotic lesions, the detectable steady-state HNE concentration reached the low-micromolar range, up to 5 to 10 µmol/L.Until rather recently, in vitro biochemical studies were oriented towards seeking evidence of the many biochemical effects of HNE, generally using concentrations above 10 µmol/L; these were normally performed by adding the aldehyde to cell cultures or suspensions or cellular subfractions. 1 Such an approach was adopted to counteract the high aldehyde metabolism shown by the majority of the cell types tested 7 ; however, it directed the investigation to quantities of HNE of rather unlikely biological interest. Further, the overall negative effects exerted by relatively high HNE dosage contributed to the short-sighted opinion that this and related lipid peroxidation products were simply detrimental and acutely toxic to cells and tissues and consequently were of limited interest in pathophysiology.This state of affairs was rectified in particular by extensive research on the role of oxidatively modified low density lipoproteins in the pathogenesis of atherosclerosis 8 and the detection in the human plasma of autoantibodies against HNE-modified low-density lipoproteins 9 or of HNE-modified proteins, 10 and a role of HNE in pathophysiology became more favorably considered.At present, because of the use of specific monoclonal antibodies raised against tissue HNE-protein adducts, the number of human diseases with detectable accumulation of HNE is rapidly growing: increased HNE levels have been recognized in the liver of patients with alcohol-induced Abbreviations: HNE, 4-hydroxy-2,3-nonenal; PKC, protein kinase C; CD, cathepsin D; DAG, diacylglycerol.From the

The chemistry of cell signaling by reactive oxygen and nitrogen species and 4-hydroxynonenal

“…This finding was supported by other reports, which, either by using PKC-βI and βII inhibitor GO6976, or by directly measuring kinase activity, demonstrated that these two PKC isozymes were activated by < 1 μM HNE (200). In contrast to PKC-β, the novel PKC-δ activity was inhibited by 0.1 μM HNE but increased by 1-10 μM HNE (199,200) . Numazawa also reported that HNE-mediated HO-1 induction was completely abrogated by dominant-negative expression of atypical PKC-ι (201), suggesting that HNE may also activate PKC-ι.…”

“…In rat hepatocyte, they demonstrated that PKC-βI and βII were activated by HNE at concentrations 0.1-1 μM, while they were inhibited when HNE concentration was higher than 1μM (1-10 μM) (199). This finding was supported by other reports, which, either by using PKC-βI and βII inhibitor GO6976, or by directly measuring kinase activity, demonstrated that these two PKC isozymes were activated by < 1 μM HNE (200).…”

Self-regulatory role of 4-hydroxynonenal in signaling for stress-induced programmed cell death

“…Thus, HNE can influence a large set of fundamental cellular processes including proliferation, cell cycle events, and apoptosis and can modulate the expression of numerous genes. This is consistent with the reported effect of HNE on many genes including c-myc, AKT, PKC, TGFβ, ASK1, JNK, Nrf2, integrins, connexins, ERK pathway genes, aldose reductase, glycogen synthase kinase, gamma-glutamyl transferase (GGT), adenylate cyclase, RalBP1, and heat shock proteins among others [3,13,25,45,52,57,65,74]. The underlying mechanisms for such a global effect of HNE on gene expression are largely unclear.…”

“…Triggers an epidermal growth factor receptor for growth inhibition [64] Rat hepatocytes Regulation of PKC beta isozymes [65] HeLa cells Affects expression of c-fos proto-oncogene and proliferation [66] Rat cerebrocortical neurons Inhibition of muscarinic acetylcholine and metabotropic glutamate receptor-mediated signaling [67] Rat hepatocytes Triggers Ca 2+ influx [68] Human cerebral arteries Induces relaxation [69] Neutrophils Stimulation of chemotaxis [70] Rat live plasma membrane Activation of adenylate cyclase [71] Hepatic tissues Activation of phospholipase c [72] Hepatoma cells Stimulation of heat shock proteins [73] K562 cells Inhibition of C-myc [74] HL60 cells Cell cycle progression and expression of differentiationassociated antigens [75] Macrophages Activates transcription factor AP-1 [76] Free Radic Biol Med. Author manuscript; available in PMC 2009 July 15.…”

Cell death and diseases related to oxidative stress:4-hydroxynonenal (HNE) in the balance

“…16 HNE interaction with key amino acids of catalytic sites could explain the inhibition of these enzymes. 16 Although HNE-dependent protein modulation relies mainly on post-translational modifications, the regulation of gene expression by HNE has also been described notably by modulation of NF-kB (nuclear factor-kappa B) and AP-1 (activator protein 1) transcription factors, which are related to Figure 1 Reactivity of HNE. Here are represented the potential reactions of HNE on the hydroxyl, carbonyl and double bond groups.…”