Our results have identified PDK-1 as the kinase that phosphorylates and activates PKC zeta in the PI 3-kinase signaling pathway. This phosphorylation and activation of PKC zeta by PDK-1 is enhanced in the presence of Ptdins-3,4-5-P3. Consistent with the notion that PKCs are enzymes that are regulated at the plasma membrane, a membrane-targeted PKC zeta is constitutively active in the absence of agonist stimulation. The association between PKC zeta and PDK-1 reveals extensive cross-talk between enzymes in the PI 3-kinase signaling pathway.

Use of ACE inhibitors or ARBs in people with CKD reduces the risk for kidney failure and cardiovascular events. ACE inhibitors also reduced the risk for all-cause mortality and were possibly superior to ARBs for kidney failure, cardiovascular death, and all-cause mortality in patients with CKD, suggesting that they could be the first choice for treatment in this population.

Lipid mediators participate in signal transduction pathways, proliferation, apoptosis, and membrane trafficking in the cell. Lipids are highly complex and diverse owing to the various combinations of polar headgroups, fatty acyl chains, and backbone structures. This structural diversity continues to pose a challenge for lipid analysis. Here we review the current state of the art in lipidomics research and discuss the challenges facing this field. The latest technological developments in mass spectrometry, the role of bioinformatics, and the applications of lipidomics in lipid metabolism and cellular physiology and pathology are also discussed.

Risk alleles at genome loci containing phospholipase A2 receptor 1 (PLA2R1) and HLA-DQA1 closely associate with idiopathic membranous nephropathy (IMN) in the European population, but it is unknown whether a similar association exists in the Chinese population and whether high-risk alleles promote the development of anti-PLA2R antibodies. Here, we genotyped 2132 Chinese individuals, including 1112 patients with IMN and 1020 healthy controls, for three single nucleotide polymorphisms (SNPs) within PLA2R1 and three SNPs within HLA genes. We also selected 71 patients, with varying genotypes, to assess for circulating anti-PLA2R antibody and for PLA2R expression in glomeruli. Three SNPs within PLA2R1 and one SNP within HLA-DQA1 strongly associated with IMN, and we noted gene-gene interactions involving these SNPs. Furthermore, these risk alleles strongly associated with the presence of anti-PLA2R antibodies and glomerular PLA2R expression. Among individuals who carried risk alleles for both genes, 73% had anti-PLA2R antibodies and 75% expressed PLA2R in glomeruli. In contrast, among individuals who carried protective genotypes of both genes, none had anti-PLA2R antibodies and glomerular expression of PLA2R was weak or absent. In conclusion, the interaction between PLA2R1 and HLA-DQA1 risk alleles associates with the development of IMN in the Chinese population. Individuals carrying risk alleles are predisposed to the generation of circulating anti-PLA2R autoantibodies, which may contribute to the development of IMN.

Abstract-Akt is a central regulator of cardiomyocyte survival after ischemic injury in vitro and in vivo, but the mechanisms regulating Akt activity in the postischemic cardiomyocyte are not known. Furthermore, although much is known about the detrimental role that the c-Jun N-terminal kinases (JNKs) play in promoting death of cells exposed to various stresses, little is known of the molecular mechanisms by which JNK activation can be protective. We report that JNKs are necessary for the reactivation of Akt after ischemic injury. We identified Thr450 of Akt as a residue that is phosphorylated by JNKs, and the phosphorylation status of Thr450 regulates reactivation of Akt after hypoxia, apparently by priming Akt for subsequent phosphorylation by 3-phosphoinositide-dependent protein kinase. The reduction in Akt activity that is induced by JNK inhibition may have significant biological consequences, as we find that JNKs, acting via Akt, are critical determinants of survival in posthypoxic cardiomyocytes in culture. Furthermore, in contrast to selective p38 -mitogen-activated protein kinase inhibition, which was cardioprotective in vivo, concurrent inhibition of both JNKs and p38 -mitogen-activated protein kinases increased ischemia/reperfusion injury in the heart of the intact rat. These studies demonstrate that reactivation of Akt after resolution of hypoxia and ischemia is regulated by JNKs and suggest that this is likely a central mechanism of the myocyte protective effect of JNKs. (Circ Res. 2006;98:111-118.)Key Words: Akt Ⅲ apoptosis Ⅲ c-Jun NH2-terminal kinase Ⅲ hypoxia Ⅲ ischemia Ⅲ signal transduction T he families of stress-activated protein kinases (SAPKs) consist of the c-Jun N-terminal kinase (JNK) family and the p38 -mitogen-activated protein kinase (MAPK) family. 1 They are potently activated by a number of cellular stresses and produce a number of biological responses that vary by the stimulus and the cell type. These kinases are activated by ischemia (especially p38-MAPKs 2 ) and by reperfusion of ischemic tissues (JNKs and to a lesser extent p38-MAPKs 3 ).Recently, a potent and relatively selective inhibitor of the ␣ and ␤ p38-MAPK isoforms has demonstrated reductions in ischemic injury in animal models of myocardial infarction and stroke. 4,5 In addition, overexpression of dominant negative mutants of components of the p38-MAPK pathway in transgenic mice protected hearts from ischemia/reperfusion (I/R) injury. 6 However, the roles played by the JNKs in ischemic injury are much less clear than those of p38-MAPKs. This is due in large part to the fact that potent and selective inhibitors of the JNKs have only very recently been developed, are not widely available, and, to our knowledge, have not been used to study I/R injury either in vivo or in cultured cardiomyocytes.In support of a deleterious role for JNKs in ischemic injury, studies in mice in which the JNK3 gene has been deleted and studies with a peptide inhibitor of JNKs demonstrated markedly reduced ischemic injury and excitotoxicity in th...

Gel-free proteomics has emerged as a complement to conventional gel-based proteomics. Gel-free approaches focus on peptide or protein fractionation, but they do not address the efficiency of protein processing. We report the development of a microfluidic proteomic reactor that greatly simplifies the processing of complex proteomic samples by combining multiple proteomic steps. Rapid extraction and enrichment of proteins from complex proteomic samples or directly from cells are readily performed on the reactor. Furthermore, chemical and enzymatic treatments of proteins are performed in 50 nL effective volume, which results in an increased number of generated peptides. The products are compatible with mass spectrometry. We demonstrated that the proteomic reactor is at least 10 times more sensitive than current gel-free methodologies with one protein identified per 440 pg of protein lysate injected on the reactor. Furthermore, as little as 300 cells can be directly introduced on the proteomic reactor and analyzed by mass spectrometry.

Statin therapy reduces the risk of major cardiovascular events in patients with chronic kidney disease including those receiving dialysis.

Perturbation of lipid second messenger networks is associated with the impairment of synaptic function in Alzheimer disease. Underlying molecular mechanisms are unclear. Here, we used an unbiased lipidomic approach to profile alkylacylglycerophosphocholine second messengers in diseased tissue. We found that specific isoforms defined by a palmitic acid (16:0) at the sn-1 position, namely 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (C16:0 PAF) and 1-O-hexadecyl-sn-glycero-3-phosphocholine (C16:0 lyso-PAF), were elevated in the temporal cortex of Alzheimer disease patients, transgenic mice expressing human familial diseasemutant amyloid precursor protein, and human neurons directly exposed to amyloid-␤ 42 oligomers. Acute intraneuronal accumulation of C16:0 PAF but not C16:0 lyso-PAF initiated cyclindependent kinase 5-mediated hyperphosphorylation of tau on Alzheimer disease-specific epitopes. Chronic elevation caused a caspase 2 and 3/7-dependent cascade resulting in neuronal death. Pharmacological inhibition of C16:0 PAF signaling, or molecular strategies increasing hydrolysis of C16:0 PAF to C16:0 lyso-PAF, protected human neurons from amyloid-␤ 42 toxicity. Together, these data provide mechanistic insight into how disruptions in lipid metabolism can determine neuronal response to accumulating oligomeric amyloid-␤ 42.Alzheimer disease ͉ glycerophosphocholine ͉ lipidomics ͉ T he aberrant processing of the amyloid precursor protein to different assemblies of amyloid ␤ (A␤) peptides ranging from 37 to 42 amino acids is an early and necessary prerequisite for the development of Alzheimer disease (AD) (1). The ''amyloid cascade hypothesis'' defines generation of these smaller, toxic A␤ fragments, specifically soluble A␤ 42 oligomers, as the root cause of AD (1). The severity of AD progression, however, is highly correlated with the rate of abnormal tau processing (2). Underlying molecular mechanisms linking A␤ 42 biogenesis to the aggregation of normally soluble tau proteins into hyperphosphorylated oligomers remain elusive.A␤ 42 can activate cytosolic phospholipase A 2 (cPLA 2 ) (3, 4), a Group IVa PLA 2 that preferentially hydrolyzes arachidonic acid from the sn-2 position of 1-O-alkyl-2-arachidonoyl-and 1-O-acyl-2-arachidonoyl-glycerophospholipids (5). Inhibiting cPLA 2 activation completely attenuates A␤ 42 neurotoxicity; blocking the different metabolic arms of the arachidonic acid cascade confers only partial protection (3,4,6). Little is known about the fate of the glycerophospholipid backbone following the release of arachidonic acid by cPLA 2 , although accumulation of choline-containing lipids is associated with accelerated cognitive decline in AD (7,8). The alkyl-lyso-glycerophosphocholines and lysophosphatidylcholines (LPCs) are of particular interest (Fig. S1). These metabolites are biologically active in their own right and can be further modified by lysophosphatidylcholine acyltransferases (LPCATs). LPCAT activity also increases in AD (9), notably in the posterior-temporal entorhinal cortex, a r...