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Confocal Imaging of Neuropeptide Y-pHluorin: A Technique to Visualize Insulin Granule Exocytosis in Intact Murine and Human Islets
Published on: September 13, 2017
Expression of peptide YY by human blood leukocytes
Julia Pia Natascha Holler1, Jessica Schmitz1, Rainer Roehrig2
1Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, Justus-Liebig-University, Feulgen-Str. 10-12, D-35385 Giessen, Germany.
Abstract:
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.
Insights
Peripheral blood mononuclear cells in healthy humans express Peptide YY (PYY). However, PYY expression decreases with monocyte differentiation and inflammation, suggesting a role in immune response modulation.
Area of Science:
- Immunology
- Endocrinology
- Molecular Biology
Background:
- Peptide YY (PYY) is a hormone primarily produced in the gut with known systemic and paracrine functions.
- Its expression in immune cells, particularly peripheral blood mononuclear cells (PBMCs), has not been extensively studied.
Purpose of the Study:
- To investigate the expression of Peptide YY (PYY) mRNA and peptide in peripheral blood mononuclear cells (PBMCs).
- To examine PYY expression in differentiated THP-1 cells, an in vitro model of inflammation.
Main Methods:
- Peripheral blood was collected from healthy male donors (n=63).
- Peptide YY (PYY) mRNA levels in PBMCs were quantified.
- PBMCs were cultured, and PYY peptide levels in supernatant were measured.
- Human monocytic THP-1 cells were differentiated into macrophages and treated with lipopolysaccharide (LPS) to model inflammation.
Main Results:
- Peptide YY (PYY) mRNA was detected in PBMCs from all healthy subjects.
- PYY peptide was found in the supernatant of cultured PBMCs.
- Lipopolysaccharide (LPS) treatment led to down-regulation of PYY mRNA in differentiated THP-1 cells.
Conclusions:
- Freshly isolated peripheral blood mononuclear cells (PBMCs) from healthy individuals express Peptide YY (PYY).
- In vitro studies indicate that PYY expression is reduced during monocyte differentiation into macrophages and in response to pro-inflammatory stimuli.
