Possible roles of neuropeptide Y Y3-receptor subtype in rat aortic endothelial cell proliferation under hypoxia, and its specific signal transduction

A new biomarker neuropeptide Y and bioinformatics analysis of intrahepatic cholestasis of pregnancy

AIM

To explore the expression of neuropeptide Y (NPY) and bioinformatics characteristics of intrahepatic cholestasis of pregnancy (ICP).

METHODS

Gene chip data of intrahepatic cholestasis of pregnancy were searched from the GEO database with bioinformatics method, and GSE46157 gene chip was downloaded. Differentially expressed genes in normal pregnant placenta tissue and ICP pregnant placenta tissue (bile acid concentration > 40 μmol/L) were screened by GEO2R. Functional annotation (GO) and pathway analysis (KEGG) were performed with DAVID. STRING online database and Cytoscape software were used for protein interaction network analysis. Maternal serum NPY level of 63 cases of ICP pregnant women and 20 normal pregnant women were investigated by ELISA.

RESULTS

After screening 3896 differential genes and protein interaction, the top 14 hub genes were selected with nine up-regulated and five down-regulated genes. ICP patients were divided into three subgroups according to serum TBA and ALT levels. Maternal serum NPY levels of pregnant women in ICP subgroups 1, 2, and 3 were significantly higher than those in the normal pregnant women. The number of premature births, meconium-staining amniotic fluid, neonatal asphyxia, and NICU admission was significantly higher in the ICP subgroup 1 than in the ICP subgroups 2 and 3, and than in the normal pregnant women.

CONCLUSION

This study indicates that many differentially expressed genes and signaling pathways are involved in the pathophysiological procedure of ICP. NPY could be a new biomarker of ICP.

Updated Role of Neuropeptide Y in Nicotine-Induced Endothelial Dysfunction and Atherosclerosis

Cardiovascular disease is the leading cause of death worldwide. Endothelial dysfunction of the arterial vasculature plays a pivotal role in cardiovascular pathogenesis. Nicotine-induced endothelial dysfunction substantially contributes to the development of arteriosclerotic cardiovascular disease. Nicotine promotes oxidative inflammation, thrombosis, pathological angiogenesis, and vasoconstriction, and induces insulin resistance. However, the exact mechanism through which nicotine induces endothelial dysfunction remains unclear. Neuropeptide Y (NPY) is widely distributed in the central nervous system and peripheral tissues, and it participates in the pathogenesis of atherosclerosis by regulating vasoconstriction, energy metabolism, local plaque inflammatory response, activation and aggregation of platelets, and stress and anxiety-related emotion. Nicotine can increase the expression of NPY, suggesting that NPY is involved in nicotine-induced endothelial dysfunction. Herein, we present an updated review of the possible mechanisms of nicotine-induced atherosclerosis, with a focus on endothelial cell dysfunction associated with nicotine and NPY.

Neuropeptide Y is an angiogenic factor in cardiovascular regeneration

In diabetic cardiomyopathy, there is altered angiogenic signaling and increased oxidative stress. As a result, anti-angiogenic and pro-inflammatory pathways are activated. These disrupt cellular metabolism and cause fibrosis and apoptosis, leading to pathological remodeling. The autonomic nervous system and neurotransmitters play an important role in angiogenesis. Therapies that promote angiogenesis may be able to relieve the pathology in these disease states. Neuropeptide Y (NPY) is the most abundantly produced and expressed neuropeptide in the central and peripheral nervous systems in mammals and plays an important role in promoting angiogenesis and cardiomyocyte remodeling. It produces effects through G-protein-coupled Y receptors that are widely distributed and also present on the myocardium. Some of these receptors are also involved in diseased states of the heart. NPY has been implicated as a potent growth factor, causing cell proliferation in multiple systems while the NPY3-36 fragment is selective in stimulating angiogenesis and cardiomyocyte remodeling. Current research is focusing on developing a drug delivery mechanism for NPY to prolong therapy without having significant systemic consequences. This could be a promising innovation in the treatment of diabetic cardiomyopathy and ischemic heart disease.

Fibroblast growth factor-peptide improves barrier function and proliferation in human keratinocytes after radiation

PURPOSE

Epidermal keratinocytes, which can be severely damaged after ionizing radiation (IR), are rapid turnover cells that function as a barrier, protecting the host from pathogenic invasion and fluid loss. We tested fibroblast growth factor-peptide (FGF-P), a small peptide derived from the receptor-binding domain of FGF-2, as a potential mitigator of radiation effects via proliferation and the barrier function of keratinocytes.

METHODS AND MATERIALS

Keratinocytes isolated from neonatal foreskin were grown on transwells. After being exposed to 0, 5, or 10 Gy IR, the cells were treated with a vehicle or FGF-P. The permeability of IR cells was assessed by using transepithelial electrical resistance (TEER) and a paracellular tracer flux of fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA) with Ussing chambers. The cell proliferation was measured with yellow tetrazolium salt (MTT) and tritiated thymidine ([3H]-TdR) assays. The phosphorylation of extracellular signal-regulated kinases (ERK) was measured in an enzyme-linked immunosorbent (ELISA)-like assay, and the proteins related to tight junctions (TJ) and adherens junctions (AJ) were examined with Western blotting. We used a mouse model to assess the ability of FGF-P to promote the healing of skin β burns created with a strontium applicator.

RESULTS

We found (1) FGF-P reduced the permeability of irradiated keratinocytes, as evidenced by increased TEER and decreased diffusion of FITC-BSA, both associated with the regulation of different proteins and levels of TJ and AJ; and (2) FGF-P enhanced the proliferation of irradiated keratinocytes, as evidenced by increased MTT activity and [3H]-TdR incorporation, which was associated with activation of the ERK pathway; and (3) FGF-P promoted the healing of skin β burns.

CONCLUSIONS

FGF-P enhances the barrier function, including up-regulation of TJ proteins, increases proliferation of human keratinocytes, and accelerates the healing of skin β burns. FGF-P is a promising mitigator that improves the proliferation and barrier function of keratinocytes after IR.

Hydrogen peroxide stress stimulates phosphorylation of FoxO1 in rat aortic endothelial cells

AIM

To examine whether the phosphorylation of the O subfamily of forkhead transcription factors (FoxO) is involved in response to oxidative stress in rat aortic endothelial cells (RAECs).

METHODS

RAECs were treated with H(2)0(2) and phosphorylation status of proteins were evaluated by Western blot analysis. The subcellular localization of FoxO1 was determined by nuclear and cytosolic fractionation followed by Western blot analysis as well as immunocytochemistry. The transcriptional activity of FoxO1 in H(2)0(2) stress was assessed by luciferase reporter assay. Expression of FoxO1 target gene was determined by real-time PCR analysis.

RESULTS

H(2)0(2) stress stimulated phosphorylation of FoxO1 at Thr24 and Ser256 in a concentration and time dependent manner in RAECs. Pretreatment of RAECs with PI-3K inhibitors abolished the activation of Akt and prevented the phosphorylation of FoxO1. Akt-mediated phosphorylation promoted nuclear exclusion of FoxO1. An IRS-driven luciferase activity transactivated by exogenous FoxO1 was modestly suppressed by hydrogen peroxide stress. The expression of Bim, a target gene of FoxO factors, was negatively regulated by Akt-mediated phosphorylation in response to hydrogen peroxide stimulation.

CONCLUSION

Our data demonstrate that phosphorylation of FoxO1 by PI-3K/Akt signaling is implicated in response to oxidative stress in vascular endothelial cells.

Peptidergic influences on proliferation, migration, and placement of neural progenitors in the adult mouse forebrain

Neural progenitor proliferation, differentiation, and migration are continually ongoing processes in the subventricular zone (SVZ) and rostral migratory stream (RMS) of the adult brain. There is evidence that peptidergic systems may be involved in the molecular cascades regulating these neurogenic processes, and we examined a possible influence of neuropeptide Y (NPY) and cholecystokinin (CCK) systems in cell proliferation and neuroblast formation in the SVZ and RMS and generation of interneurons in the olfactory bulb (OB). We show that NPY and the Y1 and Y2 receptor (R) proteins are expressed in and surrounding the SVZ and RMS and that Y1R is located on neuroblasts in the anterior RMS. Mice deficient in Y1Rs or Y2Rs have fewer Ki-67-immunoreactive (ir) proliferating precursor cells and doublecortin-ir neuroblasts in the SVZ and RMS than WT mice, and less calbindin-, calretinin-, and tyrosine hydroxylase-ir interneurons in the OB. Mice lacking CCK1Rs have fewer proliferating cells and neuroblasts than normal and a shortage of interneurons in the OB. These findings suggest that both NPY and CCK through their receptors help to regulate the proliferation of precursor cells, the amount of neuroblast cells in the SVZ and RMS, and influence the differentiation of OB interneurons.