Neuropeptide Ys-Regulate Food Intake & Body Weight

Role of salivary PYY in the modulation of food intake.

This is a study that comprehensively shows the expression of Neuropeptide Ys  (PYY _3–36 ) are present in saliva and showed the expression of its preferred receptor, Y2R, in the basal layer of the progenitor cells of the tongue epithelia and von Ebner's gland. The researchers used our Y2R antibody (dilution 1:3000) to determine level of expression. This receptor appears to be the main player in mediating hunger and body weight: Hurtado MD, Acosta A, Riveros PP, Baum BJ, Ukhanov K, et al. (2012) Distribution of Y-Receptors in Murine Lingual Epithelia. PLoS ONE 7(9): e46358. doi:10.1371/journal.pone.0046358.

Images: Immunolocalization of Y1, Y2, Y4, and Y5 receptors (Rs) in the dorsal epithelium of murine tongue. Images: Mirror section pairs (Panels A and B, C and D, E and F) were hybridized to the respective YR antibody (green), followed by DAPI counterstain (blue), as indicated in the upper left corner of each panel. For better viewing, the confocal images in B, D, and F were reflected horizontally. Representative areas of the epithelium, positive for either YR (dashed rectangles in the left-sided panels), are shown as close-up images on the right next to each respective panel. The irregular columned structures at the epithelial surface are transversely sectioned filiform papillae. G - Y4R-positive neuronal fibers (green) are located in the subepithelial region underlying the basal laminae. H – co-localization of Y4R and NCAM (red) immunoreactivity within mechanoreceptors of Meissner corpuscles (MC). As a morpho-histological reference of the dorsal lingual epithelium structure, an hematoxylin and eosin stained section is shown in panel I. Panel J shows a hypothetical diagram of a lingual dorsal epithelium layer and the differentiation/migration lineage of cell types expressing respective YR subtypes. K5 – cytokeratin-5 [2]. doi:10.1371/journal.pone.0046358.g006.

Note: this study is further validation of the potency of our NPY Y2 antibody.

Conclusion: NPY family peptides and their cognate receptors in the oral cavity may mediate a wide variety of functions, including proliferation, differentiation, motility, taste perception, as well as satiation. All of these multiple functions and their respective molecular mechanisms are subjects of the ongoing investigations.

Understanding these molecular mechanisms could provide the foundation for discovering less intrusive therapies for obesity. I will keep you posted.

Salivary Neuropeptides Y2s and Satiety

A possible new slant for combating obesity

The researchers in this study acheived a sustained increased PYY_3-36 (a neuropeptide) expression via viral vector-mediated gene delivery targeting salivary glands and the good news: this increase resulted in a significant long-term reduction in food intake (FI) and body weight (BW). This is evidence for new functions of the previously characterized gut peptide PYY_3-36 suggesting a potential simple and efficient alternative therapeutic approach for the treatment of obesity: Andres Acosta1, Maria D. Hurtado1, Oleg Gorbatyuk, Michael La Sala, David Duncan, George Aslanidi, Martha Campbell-Thompson, Lei Zhang, Herbert Herzog, Antonis Voutetakis, Bruce J. Baum, Sergei Zolotukhin. Salivary PYY: A Putative Bypass to Satiety. PLoS ONE 6(10): e26137. doi:10.1371/journal.pone.0026137. Received: July 22, 2011; Accepted: September 20, 2011; Published: October 10, 2011...Rabbit anti-Y2R (Dilution: 1:3000) using TSA...

Images: A) Immunolocalization of Y2R-positive cells in the hippocampus of C57Bl/6J mouse (WT), a (+) control. (B) Immunolocalization of Y2R in the tongue epithelia of Y2R KO mouse, a (-) control. VEG – von Ebner's gland. (C) Immunolocalization of Y2R-positive cells in the CV area of the tongue of a C57Bl/6J mouse. (D) close-up of (C). (E), and (F) close ups of (D), top and bottom rectangles, respectively. doi:10.1371/journal.pone.0026137.g003

These findings could prove a first step in identifying new targets for obesity fighting therapies. Increasing PYY salivary output would provide satiety with less food intake. This would give a whole new perspective on dieting. If we are satsified with less food intake is this really dieting? Stay tuned.

AgRP's Role in Energy Homeostasis

This blog has featured various posting on the building blocks and involved in Energy Homeostasis. This is key to future therapies for Obesity and Diabetes.
Here researchers study: Yongheng Cao1, Masanori Nakata, Shiki Okamoto, Eisuke Takano, Toshihiko Yada, Yasuhiko Minokoshi, Yukio Hirata, Kazunori Nakajima, Kristy Iskandar, Yoshitake Hayashi, Wataru Ogawa, Gregory S. Barsh, Hiroshi Hosoda, Kenji Kangawa, Hiroshi Itoh, Tetsuo Noda, Masato Kasuga, Jun Nakae.PDK1-Foxo1 in Agouti-Related Peptide Neurons Regulates Energy Homeostasis by Modulating Food Intake and Energy Expenditure. PLoS ONE 6(4): e18324. doi:10.1371/journal.pone.0018324.

IHC Protocol: For immunofluorescence analyses, mice were transcardially perfused with saline followed by 4% paraformaldehyde in 0.1 M phosphate-buffered saline, pH 7.4 (PBS). The brains were dissected and immersed in 4% paraformaldehyde at 4°C overnight and then soaked in 30% sucrose overnight. Frozen, free-floating coronal sections (4 µm thick) were cut through the arcuate nucleus with a microtome (Leica Microsystems). The sections were washed extensively in PBS for 20 min to quench endogenous peroxidase activity. For double staining of PDK1 and AGRP, the sections were stained with a Renaissance Tyramide Signal Amplification kit (#NEL701, Perkin Elmer, Waltham, MA) according to the manufacturer's protocol. The primary antibodies were Ab-241 (Signalway Antibody, Pearland, TX) for PDK1 and GT15023 (Neuromics, Edina, MN) for AGRP; the secondary antibodies were Alexa FluorR 594 chicken anti-rabbit IgG and Alexa FluorR 488 donkey anti-goat IgG (Molecular Probes, Eugene, OR). For double staining of Foxo1 and AGRP, we used an anti-FOXO1A antibody (ab12161, abcamR, Cambridge, UK), respectively. For double staining of FLAG and AGRP, the sections were stained using a Renaissance Tyramide Signal Amplification kit according to the manufacturer's protocol. The primary antibodies were the OctA-Probe (D-8: sc-807, Santa Cruz Biotechnology, Inc, Santa Cruz, CA); the secondary antibodies were Alexa FluorR 594 chicken anti-rabbit IgG and Alexa FluorR 488 donkey anti-goat IgG (Invitrogen, Carlsbad, CA).

Images: Functional defects of AGRP neurons in AGRPPdk1−/− mice. (A) Numbers of AGRP positive cells in the arcuate nuclei of AGRPPdk1+/+ (gray bar) and AGRPPdk1−/− (blue bar) mice. AGRP cell counts indifferent regions of the arcuate nucleus showed different numbers of AGRP neurons in AGRPPdk1+/+ (n = 3) and AGRPPdk1−/− mice (n = 3). (B) Representative Immunofluorescence images of AGRP in the hypothalamic regions of AGRPPdk1+/+ (left panel) and AGRPPdk1−/− mice (right panel). Green, AGRP; blue, DAPI. Scale bars indicate 100 µm. (C) Expression in the fed-state of hypothalamic neuropeptide genes in control (gray bar) and AGRPPdk1−/−(blue bar) mice. Data were normalized to β-actin expression and represent the mean ± SEM of six mice per genotype.

doi:10.1371/journal.pone.0018324.g002

Key Findings:PDK1 and Foxo1 signaling pathways play important roles in the control of energy homeostasis through AGRP-independent mechanisms. data indicated that PDK1 was indispensable for the orexigenic activity of AGRP neurons. Hypothalamic AGRP neurons express AGRP, NPY, the neurotransmitter GABA, and potentially other undiscovered molecules. In AGRPPdk1−/− mice, the expression of Agrp and Npy tended to be lower than that observed in control mice although the difference was not significant. Interestingly, the Δ256Foxo1AGRPPdk1−/− mice exhibited significantly increased food intake compared to AGRPPdk1−/− mice in spite of significantly decreased expression of Agrp and Npy. Therefore, changes in the expression levels of Agrp and Npy may not explain the changes in food intake in AGRPPdk1−/− mice.

Featured and Related Reagents:
Agouti-Related Protein-Cat#: GT15023
Agouti-Related Protein (Human)-Goat
Agouti-Related Protein (Mouse)-Monoclonal
Neuropeptide and Neuropeptide Receptor Antibodies
Diabetes and Obesity Research Antibodies
Diabetes and Obesity Research

NPY Y2R and IHC-Mouse Distal Colon

Lixin Wang, Guillaume Gourcerol, Pu-Qing Yuan, S. Vincent Wu, Mulugeta Million, Muriel Larauche, and Yvette Taché. Peripheral peptide YY inhibits propulsive colonic motor function through Y2 receptor in conscious mice. Am J Physiol Gastrointest Liver Physiol (November 5, 2009). doi:10.1152/ajpgi.00349.2009.
...Note: Excellent IHC staining of myenteric plexus and submucosal (mouse distal colon) tissue-Free floating submucosal and LMMP whole mounts of both proximal and distal colon from 3 naïve mice were treated in 10% normal goat serum each for 30 min, and followed by incubation with polyclonal rabbit anti- NPY Y2 Receptor diluted at 1:1,000 (Neuromics, Inc., Edina, MN)...

Related Antibodies to Consider:
NPY Y2 Receptor-C/N Terminus
NPY Y1 Receptor
ppNPY
All Neuropeptide and Neuropeptide Receptor Antibodies
Pain and Inflammation Research Antibodies
Diabetes and Obesity Research Antibodies