Peptide YY mediates inhibition of tumor growth and inflammation

Peptide YY inhibits transcription and replication of hepatitis B virus by suppressing promoter/enhancer activity

Hepatitis B virus (HBV) infection is a noteworthy cause of liver diseases, especially cirrhosis and hepatocellular carcinomas. However, the interaction between the host and HBV has not been fully elucidated. Peptide YY (PYY) is a 36-amino-acid gastrointestinal hormone that is mainly involved in the regulation of the human digestive system. This study found that PYY expression was reduced in HBV-expressing hepatocytes and HBV patients. Overexpression of PYY could significantly inhibit HBV RNA, DNA levels, and the secretion of HBsAg. In addition, PYY inhibits HBV RNA dependent on transcription through reducing the activities of CP/Enh I/II, SP1 and SP2. Meanwhile, PYY blocks HBV replication independent on core, polymerase protein and ε structure of pregenomic RNA. These results suggest that PYY can impair HBV replication by suppressing viral promoters/enhancers in hepatocytes. Our data shed light on a novel role for PYY as anti-HBV restriction factor.

Neuropeptide Y Peptide Family and Cancer: Antitumor Therapeutic Strategies

Currently available data on the involvement of neuropeptide Y (NPY), peptide YY (PYY), and pancreatic polypeptide (PP) and their receptors (YRs) in cancer are updated. The structure and dynamics of YRs and their intracellular signaling pathways are also studied. The roles played by these peptides in 22 different cancer types are reviewed (e.g., breast cancer, colorectal cancer, Ewing sarcoma, liver cancer, melanoma, neuroblastoma, pancreatic cancer, pheochromocytoma, and prostate cancer). YRs could be used as cancer diagnostic markers and therapeutic targets. A high Y1R expression has been correlated with lymph node metastasis, advanced stages, and perineural invasion; an increased Y5R expression with survival and tumor growth; and a high serum NPY level with relapse, metastasis, and poor survival. YRs mediate tumor cell proliferation, migration, invasion, metastasis, and angiogenesis; YR antagonists block the previous actions and promote the death of cancer cells. NPY favors tumor cell growth, migration, and metastasis and promotes angiogenesis in some tumors (e.g., breast cancer, colorectal cancer, neuroblastoma, pancreatic cancer), whereas in others it exerts an antitumor effect (e.g., cholangiocarcinoma, Ewing sarcoma, liver cancer). PYY or its fragments block tumor cell growth, migration, and invasion in breast, colorectal, esophageal, liver, pancreatic, and prostate cancer. Current data show the peptidergic system's high potential for cancer diagnosis, treatment, and support using Y2R/Y5R antagonists and NPY or PYY agonists as promising antitumor therapeutic strategies. Some important research lines to be developed in the future will also be suggested.

Identification and Verification of Core Genes in Colorectal Cancer

Colorectal cancer, a malignant neoplasm that occurs in the colorectal mucosa, is one of the most common types of gastrointestinal cancer. Colorectal cancer has been studied extensively, but the molecular mechanisms of this malignancy have not been characterized. This study identified and verified core genes associated with colorectal cancer using integrated bioinformatics analysis. Three gene expression profiles (GSE15781, GSE110223, and GSE110224) were downloaded from the Gene Expression Omnibus (GEO) databases. A total of 87 common differentially expressed genes (DEGs) among GSE15781, GSE110223, and GSE110224 were identified, including 19 upregulated genes and 68 downregulated genes. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis was performed for common DEGs using clusterProfiler. These common DEGs were significantly involved in cancer-associated functions and signaling pathways. Then, we constructed protein-protein interaction networks of these common DEGs using Cytoscape software, which resulted in the identification of the following 10 core genes: SST, PYY, CXCL1, CXCL8, CXCL3, ZG16, AQP8, CLCA4, MS4A12, and GUCA2A. Analysis using qRT-PCR has shown that SST, CXCL8, and MS4A12 were significant differentially expressed between colorectal cancer tissues and normal colorectal tissues (P < 0.05). Gene Expression Profiling Interactive Analysis (GEPIA) overall survival (OS) has shown that low expressions of AQP8, ZG16, CXCL3, and CXCL8 may predict poor survival outcome in colorectal cancer. In conclusion, the core genes identified in this study contributed to the understanding of the molecular mechanisms involved in colorectal cancer development and may be targets for early diagnosis, prevention, and treatment of colorectal cancer.

Changes in plasma levels of cholecystokinin, neurotensin, VIP and PYY in gastric and colorectal cancer - Preliminary results

Physiological roles of enterohormones such as secretion, absorption and digestion were supported by clinical data. Overexpression of cholecystokinin (CCK), neurotensin (NT) and vasoactive intestinal peptide (VIP) receptors occur in gastrointestinal (GI) malignancies. The aim of the paper was to compare plasma levels of CCK, peptide YY (PYY), VIP and NT in patients with gastrointestinal malignancies and healthy controls. The study included 80 patients (37 men and 43 women) with GI malignancies (20 with gastric and 60 with colorectal cancers). Median age of the patients was 62.9 years (range: 40-85 years). Control group was comprised of 30 healthy persons with median age 59.8 years (range: 40-82 years). Fasting plasma concentrations of CKK, PYY, NT, and VIP were determined at rest, using ELISA kits for automated systems. Comparative analysis of enterohormone levels in patients with various types of gastrointestinal malignancies demonstrated presence of some cancer-specific alterations. Patients with gastric cancers presented with lower plasma concentrations of CCK than healthy controls and individuals from colorectal cancers (p = 0.02). The highest plasma concentrations of neurotensin was found in colorectal cancer patients in comparison to gastric (p = 0.02). The plasma levels of VIP observed in gastric cancer group were lower than in colorectal cancer patients (p = 0.01). Patients with GI malignancies may present with tumor-specific alterations in plasma enterohormone levels.

The potential probiotic Lactobacillus rhamnosus CNCM I-3690 strain protects the intestinal barrier by stimulating both mucus production and cytoprotective response

The gut barrier plays an important role in human health. When barrier function is impaired, altered permeability and barrier dysfunction can occur, leading to inflammatory bowel diseases, irritable bowel syndrome or obesity. Several bacteria, including pathogens and commensals, have been found to directly or indirectly modulate intestinal barrier function. The use of probiotic strains could be an important landmark in the management of gut dysfunction with a clear impact on the general population. Previously, we found that Lactobacillus rhamnosus CNCM I-3690 can protect intestinal barrier functions in mice inflammation model. Here, we investigated its mechanism of action. Our results show that CNCM I-3690 can (i) physically maintain modulated goblet cells and the mucus layer and (ii) counteract changes in local and systemic lymphocytes. Furthermore, mice colonic transcriptome analysis revealed that CNCM I-3690 enhances the expression of genes related to healthy gut permeability: motility and absorption, cell proliferation; and protective functions by inhibiting endogenous proteases. Finally, SpaFED pili are clearly important effectors since an L. rhamnosus ΔspaF mutant failed to provide the same benefits as the wild type strain. Taken together, our data suggest that CNCM I-3690 restores impaired intestinal barrier functions via anti-inflammatory and cytoprotective responses.

Crosstalk between intestinal microbiota, adipose tissue and skeletal muscle as an early event in systemic low-grade inflammation and the development of obesity and diabetes

Obesity is associated with a systemic chronic low-grade inflammation that contributes to the development of metabolic disorders such as cardiovascular diseases and type 2 diabetes. However, the etiology of this obesity-related pro-inflammatory process remains unclear. Most studies have focused on adipose tissue dysfunctions and/or insulin resistance in skeletal muscle cells as well as changes in adipokine profile and macrophage recruitment as potential sources of inflammation. However, low-grade systemic inflammation probably involves a complex network of signals interconnecting several organs. Recent evidences have suggested that disturbances in the composition of the gut microbial flora and alterations in levels of gut peptides following the ingestion of a high-fat diet may be a cause of low-grade systemic inflammation that may even precede and predispose to obesity, metabolic disorders or type 2 diabetes. This hypothesis is appealing because the gastrointestinal system is first exposed to nutrients and may thereby represent the first link in the chain of events leading to the development of obesity-associated systemic inflammation. Therefore, the present review will summarize the latest advances interconnecting intestinal mucosal bacteria-mediated inflammation, adipose tissue and skeletal muscle in a coordinated circuitry favouring the onset of a high-fat diet-related systemic low-grade inflammation preceding obesity and predisposing to metabolic disorders and/or type 2 diabetes. A particular emphasis will be given to high-fat diet-induced alterations of gut homeostasis as an early initiator event of mucosal inflammation and adverse consequences contributing to the promotion of extended systemic inflammation, especially in adipose and muscular tissues.

Immunohistochemical distribution of neuropeptide Y, peptide YY, pancreatic polypeptide-like immunoreactivity and their receptors in the epidermal skin of healthy women

Few studies have suggested that neuropeptide Y (NPY) could play an important role in skin functions. However, the expression of NPY, the related peptides, peptide YY (PYY) and pancreatic polypeptide (PP) and their receptors have not been investigated in human skin. Using specific antisera directed against NPY, PYY, PP and the Y1, Y2, Y4 and Y5 receptor subtypes, we investigated here the expression of these markers. NPY-like immunoreactivity (ir) in the epidermal skin could not be detected. For the first time we report the presence of positive PP-like ir immunofluorescent signals in epidermal cells, i.e. keratinocytes of skin from three areas (abdomen, breast and face) obtained as surgical left-overs. The immunofluorescent signal of PP-like ir varies from very low to high level in all three areas. In contrast, PYY-like ir is only expressed in some cells and with varied level of intensity. Furthermore and for the first time we observed specific Y1 and Y4 receptor-like ir in all epidermal layers, while the Y2 and Y5 subtypes were absent. Interestingly, as seen in human epidermis, in Episkin, a reconstituted human epidermal layer, we detected the presence of PP-like as well as Y1-like and Y4-like ir. These data have shown the presence and distribution of PYY, PP and Y1 and Y4 receptors in the human skin and Episkin, suggesting possible novel roles of NPY related peptides and their receptors in skin homeostasis.

Expression of peptide YY by human blood leukocytes

Peptide YY is produced by L cells in the mucosa of the distal ileum, colon, and rectum and may have systemic and paracrine functions. We hypothesized that peptide YY is expressed by peripheral blood mononuclear cells. The purpose of the present study was to evaluate the expression of peptide YY mRNA and peptide by peripheral blood mononuclear cells and differentiated THP-1 cells after lipopolysaccharide treatment as an in vitro model of inflammation. Blood was drawn by venipuncture from 18- to 63-year-old healthy male blood donors (n=63); peptide YY mRNA expression levels were detected in peripheral blood mononuclear cells from all healthy male subjects. In 3 subjects, peripheral blood mononuclear cells were cultured for 3 and 24h and peptide YY was detected in the cell culture supernatant. In human monocytic THP-1 cells treated with phorbol-12-myristate-13-acetate to induce differentiation to macrophages, treatment with lipopolysaccharide caused down-regulation of peptide YY mRNA levels. In summary, freshly isolated peripheral blood mononuclear cells from healthy humans expressed peptide YY. In vitro data suggested that peptide YY expression is down-regulated by differentiation of monocytes to macrophages and proinflammatory stimuli.