GLP-1 Receptor Localization in Monkey and Human Tissue: Novel Distribution Revealed With Extensively Validated Monoclonal Antibody

Glucagon-like peptide 1 (GLP-1) analogs are increasingly being used in the treatment of type 2 diabetes. It is clear that these drugs lower blood glucose through an increase in insulin secretion and a lowering of glucagon secretion; in addition, they lower body weight and systolic blood pressure and increase heart rate. Using a new monoclonal antibody for immunohistochemistry, we detected GLP-1 receptor (GLP-1R) in important target organs in humans and monkeys. In the pancreas, GLP-1R was predominantly localized in β-cells with a markedly weaker expression in acinar cells. Pancreatic ductal epithelial cells did not express GLP-1R. In the kidney and lung, GLP-1R was exclusively expressed in smooth muscle cells in the walls of arteries and arterioles. In the heart, GLP-1R was localized in myocytes of the sinoatrial node. In the gastrointestinal tract, the highest GLP-1R expression was seen in the Brunner's gland in the duodenum, with lower level expression in parietal cells and smooth muscle cells in the muscularis externa in the stomach and in myenteric plexus neurons throughout the gut. No GLP-1R was seen in primate liver and thyroid. GLP-1R expression seen with immunohistochemistry was confirmed by functional expression using in situ ligand binding with 125I-GLP-1. In conclusion, these results give important new insight into the molecular mode of action of GLP-1 analogs by identifying the exact cellular localization of GLP-1R.

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Faculty Opinions recommendation of Trpv1 reporter mice reveal highly restricted brain distribution and functional expression in arteriolar smooth muscle cells.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.9581956.10326054 ◽

2011 ◽

Author(s):

Michael Andresen

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Muscle Cells ◽

Functional Expression ◽

Brain Distribution ◽

Reporter Mice

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Growth-dependent alterations of intracellular Ca(2+)-handling mechanisms of vascular smooth muscle cells. PDGF negatively regulates functional expression of voltage-dependent, IP3-mediated, and CA(2+)-induced Ca2+ release channels.

Circulation Research ◽

10.1161/01.res.69.5.1327 ◽

1991 ◽

Vol 69 (5) ◽

pp. 1327-1339 ◽

Cited By ~ 24

Author(s):

M Masuo ◽

T Toyo-oka ◽

W S Shin ◽

T Sugimoto

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Muscle Cells ◽

Functional Expression ◽

Voltage Dependent ◽

Intracellular Ca

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Progesterone-dependent expression of keratinocyte growth factor mRNA in stromal cells of the primate endometrium: keratinocyte growth factor as a progestomedin.

The Journal of Cell Biology ◽

10.1083/jcb.125.2.393 ◽

1994 ◽

Vol 125 (2) ◽

pp. 393-401 ◽

Cited By ~ 122

Author(s):

T Koji ◽

M Chedid ◽

J S Rubin ◽

O D Slayden ◽

K G Csaky ◽

...

Keyword(s):

Smooth Muscle ◽

Growth Factor ◽

Smooth Muscle Cells ◽

Stromal Cells ◽

Cellular Localization ◽

Keratinocyte Growth Factor ◽

Muscle Cells ◽

Northern Analysis ◽

Enzyme Linked Immunosorbent Assay ◽

Ru 486

In vitro studies have shown that keratinocyte growth factor (KGF, also known as FGF-7) is secreted by fibroblasts and is mitogenic specifically for epithelial cells. Therefore, KGF may be an important paracrine mediator of epithelial cell proliferation in vivo. Because stromal cells are thought to influence glandular proliferation in the primate endometrium, we investigated the hormonal regulation and cellular localization of KGF mRNA expression in the rhesus monkey uterus. Tissues were obtained both from naturally cycling monkeys in the follicular and luteal phases of the cycle, and from spayed monkeys that were either untreated or treated with estradiol (E2) alone, E2 followed by progesterone (P), E2 plus P, or E2 plus P plus an antiprogestin (RU 486). Northern blot analysis of total RNA with 32P-labeled probes revealed that the level of KGF mRNA in the endometrium was 70-100-fold greater in the luteal phase or after P treatment than in untreated, E2-treated, or follicular phase animals. Northern analysis also showed that KGF mRNA was present in the myometrium but was unaffected by hormonal state. RU 486 treatment prevented the P-induced elevation of endometrial KGF mRNA. P-dependent elevation of endometrial KGF expression was confirmed by measurement of KGF protein in tissue extracts using a two-site enzyme-linked immunosorbent assay. In situ hybridization with nonradioactive digoxigenin-labeled cDNA probes revealed that the KGF mRNA signal, which was present only in stromal and smooth muscle cells, was substantially increased by P primarily in the stromal cells located in the basalis region. Smooth muscle cells in the myometrium and the walls of the spiral arteries also expressed KGF mRNA, but the degree of this expression did not differ with hormonal state. P treatment led to increased proliferation in the glandular epithelium of the basalis region and to extensive growth of the spiral arteries. We conclude that the P-dependent increase in endometrial KGF resulted from a dual action of P: (a) a P-dependent induction of KGF expression in stromal cells, especially those in the basalis (zones III and IV), and (b) a P-dependent increase in the number of KGF-positive vascular smooth muscle cells caused by the proliferation of the spiral arteries. KGF is one of the first examples in primates of a P-induced, stromally derived growth factor that might function as a progestomedin.

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A 90-kDa surface antigen of immature smooth muscle cells is ICAM-1

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1991.261.4.l21 ◽

1991 ◽

Vol 261 (4) ◽

pp. L21-L22

Author(s):

O. Yu. Printseva ◽

M. M. Peclo ◽

A. V. Tjurmin ◽

A. M. Gown

Keyword(s):

Monoclonal Antibody ◽

Smooth Muscle ◽

Monoclonal Antibodies ◽

Smooth Muscle Cells ◽

Molecular Mass ◽

Surface Antigen ◽

Muscle Cells ◽

Human Aorta ◽

Long Term Culture

A monoclonal antibody, designated 10F3, that reacts with an antigen of molecular mass 90,000 Da has been developed by immunization of BALB/c mice with smooth muscle cells in long-term culture. The cells were originally isolated from fetal human aorta. The 10F3 was identified as an antibody that reacts with the ICAM-1 molecule. ICAM-1 is a mesenchymal antigen that is lost during differentiation of cells other than endothelium but is reexpressed by the intimal cells of vessels involved in atherogenesis. atherosclerosis; monoclonal antibodies

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Cellular localization of mitochondria contributes to Kv channel-mediated regulation of cellular excitability in pulmonary but not mesenteric circulation

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.90341.2008 ◽

2009 ◽

Vol 296 (3) ◽

pp. L347-L360 ◽

Cited By ~ 23

Author(s):

Amy L. Firth ◽

Dmitri V. Gordienko ◽

Kathryn H. Yuill ◽

Sergey V. Smirnov

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Cellular Localization ◽

Oxygen Sensor ◽

Muscle Cells ◽

Complex Iii ◽

Functional Coupling ◽

Antimycin A ◽

Patch Clamp Technique ◽

Mitochondrial Inhibitors

Mitochondria are proposed to be a major oxygen sensor in hypoxic pulmonary vasoconstriction (HPV), a unique response of the pulmonary circulation to low oxygen tension. Mitochondrial factors including reactive oxygen species, cytochrome c, ATP, and magnesium are potent modulators of voltage-gated K+ (Kv) channels in the plasmalemmal membrane of pulmonary arterial (PA) smooth muscle cells (PASMCs). Mitochondria have also been found close to the plasmalemmal membrane in rabbit main PA smooth muscle sections. Therefore, we hypothesized that differences in mitochondria localization in rat PASMCs and systemic mesenteric arterial smooth muscle cells (MASMCs) may contribute to the divergent oxygen sensitivity in the two different circulations. Cellular localization of mitochondria was compared with immunofluorescent labeling, and differences in functional coupling between mitochondria and Kv channels was evaluated with the patch-clamp technique and specific mitochondrial inhibitors antimycin A (acting at complex III of the mitochondrial electron transport chain) and oligomycin A (which inhibits the ATP synthase). It was found that mitochondria were located significantly closer to the plasmalemmal membrane in PASMCs compared with MASMCs. Consistent with these findings, the effects of the mitochondrial inhibitors on Kv current ( IKv) were significantly more potent in PASMCs than in MASMCs. The cytoskeletal disruptor cytochalasin B (10 μM) also altered mitochondrial distribution in PASMCs and significantly attenuated the effect of antimycin A on the voltage-dependent parameters of IKv. These findings suggest a greater structural and functional coupling between mitochondria and Kv channels specifically in PASMCs, which could contribute to the regulation of PA excitability in HPV.

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