No abstract

Cytokines are multifunctional proteins that play a critical role in cellular communication and activation. Cytokines have been classified as being proinflammatory (T helper 1, Th1) or anti-inflammatory (T helper 2, Th2) depending on their effects on the immune system. However, cytokines impact a variety of tissues in a complex manner that regulates inflammation, cell death, and cell proliferation and migration as well as healing mechanisms. Ethanol (alcohol) is known to alter cytokine levels in a variety of tissues including plasma, lung, liver, and brain. Studies on human monocyte responses to pathogens reveal ethanol disruption of cytokine production depending upon the pathogen and duration of alcohol consumption, with multiple pathogens and chronic ethanol promoting inflammatory cytokine production. In lung, cytokine production is disrupted by ethanol exacerbating respiratory distress syndrome with greatly increased expression of transforming growth factor beta (TGFbeta). Alcoholic liver disease involves an inflammatory hepatitis and an exaggerated Th1 response with increases in tumor necrosis factor alpha (TNFalpha). Recent studies suggest that the transition from Th1 to Th2 cytokines contribute to hepatic fibrosis and cirrhosis. Cytokines affect the brain and likely contribute to changes in the central nervous system that contribute to long-term changes in behavior and neurodegeneration. Together these studies suggest that ethanol disruption of cytokines and inflammation contribute in multiple ways to a diversity of alcoholic pathologies.

The dystrophin glycoprotein complex has been proposed to be involved in signal transduction. Here we have shown that laminin binding causes syntrophin to recruit Rac1 from the rabbit skeletal muscle. LamininSepharose and syntrophin-Sepharose bind a protein complex containing Rac1 from the muscle membranes. The presence of heparin, which inhibits laminin interactions, prevents recruitment of Rac1. The dystrophin glycoprotein complex recruits Rac1 via syntrophin through a Grb2⅐Sos1 complex. A syntrophin antibody also prevents recruitment of Rac1, suggesting that the signaling complex requires syntrophin. PAK1 is in turn bound by Rac1. c-Jun NH 2 -terminal kinase-p46 is phosphorylated and activated only when laminin is present, and the p54 isoform is activated when laminin is depleted or binding is inhibited with heparin. In the presence of laminin, c-Jun is activated in both skeletal muscle microsomes and in C2C12 myoblasts, and proliferation increases in C2C12 myoblasts. We postulate that this pathway signals muscle homeostasis and hypertrophy.

Most pathogens express ligands for multiple TLRs that share common downstream signaling. In this study, we investigated the effects of acute alcohol on inflammatory pathways induced by TLR2 or TLR4 ligands and their combination. In human monocytes, alcohol attenuated TLR4- but not TLR2-induced TNF-α protein and mRNA levels and NF-κB activation. In contrast, acute alcohol augmented TNF-α production when both TLR2 and TLR4 ligands were present. IL-1R-associated kinase (IRAK)-1 activity was reduced by alcohol in TLR4, but it was augmented in TLR2- plus TLR4-stimulated cells. IRAK-monocyte, an inhibitor of IRAK-1, was induced in TLR4, but it was reduced in TLR2- plus TLR4-stimulated monocytes by alcohol. This was supported by decreased IRAK-1:TRAF6 association in TLR4 induced but sustained presence of IRAK-1:TRAF6 complexes in TLR2- plus TLR4-stimulated monocytes after alcohol treatment. Phosphorylation of MAPKs such as ERK1/2 was selectively inhibited by acute alcohol in TLR4-stimulated cells. In contrast, JNK phosphorylation as well as AP-1 nuclear binding were augmented by acute alcohol in the presence of combined TLR4 and TLR2 stimulation. Consistent with this result, the JNK inhibitor prevented alcohol-induced augmentation of TNF-α production. These results suggest that acute alcohol attenuates TLR4-induced inflammation via inhibition of IRAK-1 and ERK1/2 kinases and increases in IRAK-monocyte levels in monocytes. Conversely, in the presence of TLR2 and TLR4 ligands, acute alcohol augments inflammatory responses via IRAK-1 activation and JNK phosphorylation. Thus, the complexity of TLR-mediated signals may determine attenuation or augmentation of inflammatory responses by acute alcohol.

To determine mechanisms underlying the transgenerational presence of metabolic perturbations in the intrauterine growth-restricted secondgeneration adult females (F2 IUGR) despite normalizing the in utero metabolic environment, we examined in vivo glucose kinetics and in vitro skeletal muscle postinsulin receptor signaling after embryo transfer of first generation (F1 IUGR) to control maternal environment. Female F2 rats, procreated by F1 pre-and postnatally nutrientand growth-restricted (IUGR) mothers but embryo transferred to gestate in control mothers, were compared with similarly gestating age-and sex-matched control (CON) F2 progeny. Although there were no differences in birth weight or postnatal growth patterns, the F2 IUGR had increased hepatic weight, fasting hyperglycemia, hyperinsulinemia, and unsuppressed hepatic glucose production, with no change in glucose futile cycling or clearance, compared with F2 CON. These hormonal and metabolic aberrations were associated with increased skeletal muscle total GLUT4 and pAkt concentrations but decreased plasma membrane-associated GLUT4, total pPKC, and PKC enzyme activity, with no change in total SHP2 and PTP1B concentrations in IUGR F2 compared with F2 CON. We conclude that transgenerational presence of aberrant glucose/insulin metabolism and skeletal muscle insulin signaling of the adult F2 IUGR female offspring is independent of the immediate intrauterine environment, supporting nutritionally induced heritable mechanisms contributing to the epidemic of type 2 diabetes mellitus. glucose transporter; metabolic imprinting; epigenetic inheritance EPIDEMIOLOGICAL INVESTIGATIONS have linked pre-and postnatal nutrient restriction to adult-onset insulin resistance/type 2 diabetes mellitus, obesity, hypertension, and coronary artery disease (1, 2). Mimicking these conditions, animal models exposing the fetus or newborn to malnutrition in the form of either global (8,24,32) or selective nutrient restriction (6) with concomitant growth restriction predispose the adult offspring toward developing glucose intolerance (8, 24) and insulin resistance of postreceptor insulin-signaling pathways in skeletal muscle (21) and adipose tissue (6). This phenotype of aberrant glucose/insulin homeostasis persists transgenerationally from a gestationally diabetic adult intrauterine growthrestricted (IUGR) mother to the offspring (4). Various investigations have demonstrated a role for diminished pancreatic ␤-cells in type 2 diabetes mellitus as well, an aberration that is passed on transgenerationally (3, 17, 27). Although mutations of genetic loci responsible for insulin production are inherited (33, 34), emerging information suggests epigenetic regulation underlying this transgenerational inheritance pattern (7, 13, 18).In the first-generation (F1) adult female IUGR offspring with pre-and postnatal nutrient restriction, metabolic adaptations concerning glucose/insulin homeostasis consist of a diminution in glucose-induced insulin response with emerging hepatic insulin resistance (8) ...