Hepatocyte growth factor enhances IL-1β stimulated IL-8 secretion by Caco-2 epithelial cells

Hepatocyte growth factor (HGF) can induce proliferation and migration of intestinal epithelial cells and has also been shown to be important in wound healing of inflamed mucosal tissues. HGF is known to be expressed along with interleukin-1 (IL-1) by inflamed mucosal tissues, yet the effect of HGF on IL-1-induced proinflammatory cytokine responses by colonic epithelial cells is unknown. In this report, we have examined the effect of HGF on IL-1-induced secretion of IL-8 by the Caco-2 colonic epithelial cell line. HGF stimulation alone had no effect on the secretion of IL-8 by the Caco-2 cells. However, culture of the cells with HGF and suboptimal levels of IL-1 resulted in a significant enhancement of IL-8 secretion compared to cells cultured with IL-1 alone. A similar effect was seen with HGF and IL-1 simulation of monocyte chemoattractant protein-1 secretion by the rat IEC-6 intestinal epithelial cell line. The enhancing effect of HGF was seen regardless of whether the culture medium contained serum or not. Simultaneous stimulation with HGF and IL-1 was required for the enhancing effect as cells pretreated with HGF for 24 h and then stimulated with IL-1 alone secreted IL-8 levels similar to that of cells stimulated with IL-1 alone. These results suggest that in addition to wound healing, HGF may play a role in the IL-1-induced chemokine response of epithelial cells in inflamed mucosal tissues.     

Intraspecific variation in Potamogeton illinoensis life history and seed germination has implications for restoration in eutrophic lakes

Hydrobiologia - Potamogeton illinoensis is a North American macrophyte, commonly the focus of management, but limited knowledge of its life history hampers conservation and restoration efforts. We...     

Structure and Evolution of the Archaeal Lipid Synthesis Enzyme sn-Glycerol-1-phosphate Dehydrogenase

One of the most critical events in the origins of cellular life was the development of lipid membranes. Archaea use isoprenoid chains linked via ether bonds to sn-glycerol 1-phosphate (G1P), whereas bacteria and eukaryotes use fatty acids attached via ester bonds to enantiomeric sn-glycerol 3-phosphate. NAD(P)H-dependent G1P dehydrogenase (G1PDH) forms G1P and has been proposed to have played a crucial role in the speciation of the Archaea. We present here, to our knowledge, the first structures of archaeal G1PDH from the hyperthermophilic methanogen Methanocaldococcus jannaschii with bound substrate dihydroxyacetone phosphate, product G1P, NADPH, and Zn²⁺ cofactor. We also biochemically characterized the enzyme with respect to pH optimum, cation specificity, and kinetic parameters for dihydroxyacetone phosphate and NAD(P)H. The structures provide key evidence for the reaction mechanism in the stereospecific addition for the NAD(P)H-based pro-R hydrogen transfer and the coordination of the Zn²⁺ cofactor during catalysis. Structure-based phylogenetic analyses also provide insight into the origins of G1PDH.     

Amino Acid Availability Regulates the Effect of Hyperinsulinemia on Skin Protein Metabolism in Pigs

The effects of amino acid supply and insulin infusion on skin protein kinetics (fractional synthesis rate (FSR), fractional breakdown rate (FBR), and net balance (NB)) in pigs were investigated. Four-month-old pigs were divided into four groups as follows: control, insulin (INS), amino acid (AA), and INS + AA groups based on the nutritional and hormonal conditions. l-[ring-¹³C₆]Phenylalanine was infused. FBR was estimated from the enrichment ratio of arterial phenylalanine to intracellular free phenylalanine. Plasma INS was increased (p < 0.05) in the INS and INS + AA groups. Plasma glucose was maintained by infusion of glucose in the groups receiving INS. The interventions did not change the NB of skin protein. However, the interventions affected the FSR and FBR differently. An infusion of INS significantly increased both FSR and FBR, although AA infusion did not. When an AA infusion was added to the infusion of insulin (INS + AA group), FSR and FBR were both lower when compared with the INS group. Our data demonstrate that in anesthetized pigs INS infusion did not exert an anabolic effect, but rather it increased AA cycling into and out of skin protein. Because co-infusion of AAs with INS ameliorated this effect, it is likely that the increased AA cycling during INS infusion was related to AA supply. Although protein kinetics were affected by both INS and AAs, none of the interventions affected the skin protein deposition. Thus, skin protein content is closely regulated under normal circumstances and is not subject to transient changes in AAs or hormonal concentrations.     

Entering adolescence: resistance to peer influence, risky behavior, and neural changes in emotion reactivity

Adolescence is often described as a period of heightened reactivity to emotions paired with reduced regulatory capacities, a combination suggested to contribute to risk-taking and susceptibility to peer influence during puberty. However, no longitudinal research has definitively linked these behavioral changes to underlying neural development. Here, 38 neurotypical participants underwent two fMRI sessions across the transition from late childhood (10 years) to early adolescence (13 years). Responses to affective facial displays exhibited a combination of general and emotion-specific changes in ventral striatum (VS), ventromedial PFC, amygdala, and temporal pole. Furthermore, VS activity increases correlated with decreases in susceptibility to peer influence and risky behavior. VS and amygdala responses were also significantly more negatively coupled in early adolescence than in late childhood while processing sad and happy versus neutral faces. Together, these results suggest that VS responses to viewing emotions may play a regulatory role that is critical to adolescent interpersonal functioning.     

Discovery, synthesis and SAR of azinyl- and azolylbenzamides antagonists of the P2X₇ receptor

The discovery, of a series of 2-Cl-5-heteroaryl-benzamide antagonists of the P2X(7) receptor via parallel medicinal chemistry is described. Initial analogs suffered from poor metabolic stability and low Vd(ss). Multi parametric optimization led to identification of pyrazole 39 as a viable lead with excellent potency and oral bioavailability. Further attempts to improve the low Vd(ss) of 39 via introduction of amines led to analogs 40 and 41 which maintained the favorable pharmacology profile of 39 and improved Vd(ss) after iv dosing. But these analogs suffered from poor oral absorption, probably driven by poor permeability.