Npy2r Antibody

What is NPY2R and why is it important in research?

NPY2R (neuropeptide Y receptor type 2) is a G-protein coupled receptor that belongs to the G-protein coupled receptor 1 family. In humans, the canonical protein has 381 amino acid residues and a molecular mass of 42.7 kDa. It is primarily localized in the cell membrane and is notably expressed in specific brain regions including the amygdala, corpus callosum, hippocampus, and subthalamic nucleus. NPY2R functions as a receptor for both neuropeptide Y and peptide YY. Its significance in research stems from its involvement in various neurological processes and its potential as a therapeutic target, particularly in neuroblastoma where it mediates tumor cell proliferation and angiogenesis .

What types of NPY2R antibodies are available for research?

Research-grade NPY2R antibodies come in various forms suitable for different experimental applications. They include polyclonal antibodies, which recognize multiple epitopes, and are available in unconjugated forms or with various conjugates for different detection methods. According to current market data, there are over 250 NPY2R antibodies available from numerous suppliers. These antibodies differ in their host species (commonly rabbit), reactivity profiles (many recognize human and mouse NPY2R), and validated applications such as Western blotting, ELISA, immunohistochemistry (IHC), and immunofluorescence (IF) .

What are the key considerations when selecting an NPY2R antibody?

When selecting an NPY2R antibody for research, several factors should be considered:

• Experimental application: Different antibodies are validated for specific applications such as Western blot, ELISA, IHC, or IF. For example, some antibodies from suppliers like Aviva Systems Biology are specifically validated for Western blotting, while others from MyBioSource are validated for ELISA and IHC .

• Species reactivity: Verify that the antibody recognizes NPY2R in your species of interest. Many commercially available antibodies recognize human and mouse NPY2R, but reactivity to other species varies .

• Antibody type: Polyclonal antibodies often provide higher sensitivity but potentially lower specificity compared to monoclonals. The search results indicate that rabbit polyclonal antibodies are common for NPY2R detection .

• Target region: Some antibodies target specific regions of NPY2R, such as the N-terminal region, which may be important depending on your experimental design .

• Validation data: Review literature and supplier validation data to ensure the antibody has been thoroughly tested in applications similar to yours.

How should NPY2R antibodies be validated before use in critical experiments?

Proper validation of NPY2R antibodies is crucial for ensuring reliable experimental results. A comprehensive validation approach should include:

• Positive and negative control tissues/cells: Use tissues known to express NPY2R (such as hippocampus or neuroblastoma cell lines) as positive controls, and tissues known not to express NPY2R as negative controls.

• Knockdown/knockout validation: If possible, validate antibody specificity by testing in NPY2R knockdown or knockout samples. This can be achieved using NPY2R siRNA in cell lines as described in the literature where NPY2R mRNA levels were reduced by approximately 70% and protein levels by 40-50% .

• Peptide competition assay: Pre-incubate the antibody with the immunizing peptide before application to verify that the signal is specifically blocked.

• Multiple antibody comparison: Use multiple antibodies targeting different epitopes of NPY2R to confirm consistent detection patterns.

• Correlation with mRNA expression: Compare protein detection with mRNA expression using techniques like RT-PCR as performed in neuroblastoma studies where both protein and mRNA levels were assessed .

What are optimal protocols for detecting NPY2R in neuroblastoma samples using immunohistochemistry?

For optimal detection of NPY2R in neuroblastoma samples using immunohistochemistry:

• Sample preparation: Fix tissue samples in 10% neutral buffered formalin and embed in paraffin. Cut sections to 4-5 μm thickness.

• Antigen retrieval: Perform heat-induced epitope retrieval using citrate buffer (pH 6.0) or as recommended by the antibody manufacturer.

• Blocking: Block endogenous peroxidase activity with 3% hydrogen peroxide, followed by protein blocking with 5% normal serum.

• Primary antibody incubation: Dilute NPY2R antibody according to manufacturer recommendations (typically 1:100 to 1:500) and incubate overnight at 4°C. Research indicates that both primary neuroblastoma samples and metastatic tissues express Y2R, with positive immunostaining observed in 80% of neuroblastoma cases .

• Detection system: Use an appropriate detection system compatible with the primary antibody host species.

• Controls: Include both positive controls (neuroblastoma tissues known to express NPY2R) and negative controls (primary antibody omitted or isotype control).

• Counterstaining: Counterstain with hematoxylin to visualize tissue architecture.

• Evaluation: Score staining intensity and distribution, noting that Y2R staining may be detected in both differentiating tumors and their undifferentiated, aggressive counterparts, as well as in tumor vasculature endothelial cells .

What are the best methods for quantifying NPY2R protein levels in experimental samples?

Quantification of NPY2R protein levels can be accomplished through several complementary methods:

• Western blotting: For semi-quantitative analysis of NPY2R protein levels:

  • Use appropriate lysis buffers containing protease inhibitors

  • Separate proteins using 10% SDS-PAGE gels

  • Transfer to PVDF or nitrocellulose membranes

  • Block with 5% non-fat milk or BSA

  • Incubate with validated NPY2R antibodies (such as those from Aviva Systems Biology validated for Western blotting)

  • Analyze band intensity using densitometry software

  • Normalize to housekeeping proteins

• ELISA: For quantitative measurement:

  • Commercial ELISA kits using NPY2R antibodies enable quantitative measurement

  • Multiple suppliers offer NPY2R antibodies validated for ELISA applications

  • Standard curves should be generated using recombinant NPY2R protein

• Flow cytometry: For quantifying NPY2R on cell surfaces:

  • Harvest cells and block non-specific binding

  • Incubate with fluorophore-conjugated NPY2R antibodies or unconjugated primary followed by fluorescent secondary antibodies

  • Analyze using flow cytometry to determine the percentage of positive cells and mean fluorescence intensity

• Immunofluorescence with image analysis: For spatial distribution analysis:

  • Fix cells/tissues and perform immunofluorescence staining with NPY2R antibodies

  • Capture images using confocal microscopy

  • Perform quantitative image analysis using software like ImageJ

How can NPY2R antibodies be used to investigate the role of NPY2R in neuroblastoma progression?

NPY2R antibodies serve as crucial tools for investigating the role of NPY2R in neuroblastoma progression through several advanced approaches:

• Expression profiling: NPY2R antibodies can be used to assess receptor expression across neuroblastoma subtypes with varying aggressiveness. Research has shown that 80% of neuroblastoma cases show positive Y2R immunostaining, with expression detected in both differentiating tumors and their undifferentiated, aggressive counterparts .

• Signaling pathway analysis: Combine NPY2R immunodetection with phospho-specific antibodies to examine downstream signaling. Studies indicate that Y2R activation leads to p44/42 MAPK pathway activation, which can be monitored to understand NPY2R's role in proliferation. Treatment with Y2R antagonist results in dose-dependent decrease in phospho-p44/42 MAPK levels .

• Co-localization studies: Use dual immunofluorescence with NPY2R antibodies and markers for proliferation (Ki67), apoptosis (cleaved caspase-3), or angiogenesis (CD31) to determine the relationship between receptor expression and these processes.

• Tumor microenvironment analysis: NPY2R antibodies can help identify expression in both tumor cells and endothelial cells within the tumor vasculature, providing insights into paracrine signaling mechanisms. Research indicates that Y2R staining is observed in both tumor cells and endothelial cells within the tumor vasculature .

• Therapeutic target validation: NPY2R antibodies can be used to monitor receptor expression before and after treatment with Y2R antagonists to correlate expression levels with treatment outcomes and potential resistance mechanisms.

What approaches can be used to study NPY2R-mediated signaling pathways in neuronal cells?

To study NPY2R-mediated signaling pathways in neuronal cells, researchers can utilize NPY2R antibodies in several sophisticated approaches:

• Phospho-specific Western blotting: Use NPY2R antibodies alongside phospho-specific antibodies to assess activation of known downstream pathways. Research indicates that Y2R signaling activates the p44/42 MAPK pathway, and Y2R antagonist treatment leads to decreased phospho-p44/42 MAPK levels after 12h of treatment .

• Proximity ligation assays (PLA): Combine NPY2R antibodies with antibodies against potential interacting proteins to visualize and quantify protein-protein interactions within intact cells.

• Co-immunoprecipitation: Use NPY2R antibodies to isolate receptor complexes and identify associated proteins through mass spectrometry or Western blotting.

• Real-time signaling visualization: Implement NPY2R antibodies in live-cell imaging experiments combined with fluorescent reporters for second messengers (calcium, cAMP) to monitor receptor activation dynamics.

• Signaling inhibitor analysis: Combine NPY2R antibody detection with selective inhibitors of signaling molecules. For example, research has shown that the MAPK inhibitor PD098059 mimics the effect of Y2R antagonist on Bim protein levels, suggesting that NPY2R regulates Bim via the MAPK pathway .

• Analysis of pro-survival vs. pro-apoptotic pathways: NPY2R antibodies can help elucidate how receptor signaling influences the balance between proliferation and apoptosis. Studies show that Y2R blockade results in increased levels of pro-apoptotic protein Bim (in all three known isoforms – BimEL, BimL and BimS) and enhanced apoptosis measured by caspase 3/7 activity .

How can NPY2R antibodies be utilized in studying the role of NPY2R in tumor angiogenesis?

NPY2R antibodies can be employed in multiple sophisticated approaches to study the role of NPY2R in tumor angiogenesis:

• Dual immunostaining of tumor vasculature: Combine NPY2R antibodies with endothelial markers (CD31, CD34) to assess receptor expression specifically in tumor-associated blood vessels. Research has shown strong Y2R staining in endothelial cells within the tumor vasculature in neuroblastoma tissues .

• Expression analysis under hypoxic conditions: Compare NPY2R expression in normoxic versus hypoxic endothelial cells using antibody-based detection methods. Studies have shown that Y2R mRNA is induced in human microvascular endothelial cells (HMVECs) by hypoxia (0.1% oxygen for 24h) .

• In vitro angiogenesis assays: Use NPY2R antibodies to correlate receptor expression with functional angiogenic responses (tube formation, migration, proliferation) in endothelial cells following treatment with neuroblastoma-conditioned media. Research indicates that Y2R antagonist (10^-6M) completely blocks the proliferative effect of NPY on endothelial cells and significantly reduces proliferation induced by neuroblastoma-conditioned media .

• Receptor regulation studies: Employ NPY2R antibodies to monitor changes in receptor expression following treatment with angiogenic factors. Studies show that NPY (10^-7M for 6h) can induce Y2R mRNA expression in endothelial cells .

• In vivo vascular analysis: Use NPY2R antibodies to assess receptor expression in tumor xenograft vasculature and correlate with vessel density, morphology, and maturation state following treatment with Y2R antagonists or NPY pathway modulators.

What are common challenges in NPY2R antibody experiments and how can they be addressed?

Researchers commonly encounter several challenges when working with NPY2R antibodies:

• Antibody specificity issues:

  • Problem: Cross-reactivity with other NPY receptor subtypes due to sequence homology.

  • Solution: Validate antibody specificity using knockdown/knockout controls. Test the antibody in cells transfected with NPY2R siRNA, which has been shown to reduce Y2R mRNA levels by approximately 70% and protein levels by 40-50% .

• Variable expression levels:

  • Problem: NPY2R expression varies across tissues and cell types, making detection challenging in low-expressing samples.

  • Solution: Optimize antibody concentration and detection methods for each sample type. Consider using amplification systems for low-expressing samples.

• Receptor internalization affecting detection:

  • Problem: NPY2R internalization following ligand binding may affect antibody accessibility.

  • Solution: Compare different fixation methods and consider timing of antibody application relative to receptor activation. For membrane-bound receptors, gentle fixation protocols may better preserve epitope accessibility.

• Post-translational modifications:

  • Problem: Glycosylation of NPY2R may mask epitopes or alter antibody binding.

  • Solution: Select antibodies raised against peptide sequences that are not subject to post-translational modifications or use multiple antibodies targeting different epitopes .

• Background in immunohistochemistry:

  • Problem: High background staining in IHC applications.

  • Solution: Optimize blocking conditions (use 5-10% serum from the same species as the secondary antibody), dilute primary antibody appropriately, and extend washing steps. Including an avidin-biotin blocking step may also help reduce background.

How can researchers reconcile contradictory data from different NPY2R antibodies?

When faced with contradictory results from different NPY2R antibodies, researchers should implement a systematic approach to reconcile the data:

• Epitope mapping comparison:

  • Compare the epitopes recognized by different antibodies. Antibodies targeting different regions of NPY2R may yield different results, particularly if certain epitopes are masked by protein interactions or post-translational modifications.

  • For example, some suppliers offer antibodies targeting the N-terminal region of NPY2R, which may perform differently than those targeting internal or C-terminal regions .

• Validation depth assessment:

  • Evaluate the extent of validation for each antibody. Thoroughly validated antibodies with multiple validation methods (Western blot, IHC, knockdown controls) should be given more weight than those with limited validation.

• Cross-validation with non-antibody methods:

  • Correlate antibody-based results with mRNA expression data from RT-PCR or RNA-seq.

  • Use functional assays such as receptor activation studies to determine which antibody results better align with functional outcomes.

  • In neuroblastoma research, for example, studies have correlated Y2R protein detection with mRNA expression levels measured by real-time RT-PCR .

• Protein conformation considerations:

  • NPY2R is a G-protein coupled receptor with a complex 3D structure. Different antibodies may recognize distinct conformational states of the receptor, particularly when comparing native versus denatured conditions.

  • Test antibodies under different sample preparation conditions (native versus denaturing).

• Statistical approach:

  • When possible, use multiple antibodies and apply statistical methods to identify consensus results.

  • Consider weighting results based on antibody validation quality.

How should researchers interpret NPY2R expression patterns in heterogeneous tumor samples?

Interpretation of NPY2R expression in heterogeneous tumor samples requires careful consideration of several factors:

• Cellular heterogeneity assessment:

  • Use dual or multi-label immunofluorescence with NPY2R antibodies and cell type-specific markers to identify which cell populations express the receptor.

  • In neuroblastoma samples, Y2R expression has been observed in both tumor cells and endothelial cells within the tumor vasculature .

• Quantitative spatial analysis:

  • Employ digital pathology approaches to quantify NPY2R expression across different regions of the tumor (core versus periphery, hypoxic versus normoxic regions).

  • Correlate expression patterns with histopathological features such as differentiation status, noting that Y2R staining is detected in both differentiating tumors and their undifferentiated, aggressive counterparts .

• Clinical correlation:

  • Correlate NPY2R expression patterns with clinical parameters (tumor stage, patient outcome) to determine the prognostic significance of heterogeneous expression.

  • Consider analyzing NPY2R expression across primary tumors and matched metastases to assess receptor dynamics during disease progression.

• Functional interpretation:

  • Interpret expression patterns in the context of known NPY2R functions. For example, expression in endothelial cells may indicate angiogenic roles, while expression in tumor cells may relate to proliferation and survival.

  • Research indicates that Y2R antagonist treatment inhibits both tumor cell proliferation and tumor vascularization in neuroblastoma models .

• Single-cell analysis:

  • When feasible, employ single-cell approaches such as mass cytometry or single-cell RNA-seq with protein detection to precisely map NPY2R expression at the individual cell level across the tumor.

What are promising approaches for developing more specific NPY2R detection methods?

Development of more specific NPY2R detection methods presents several promising avenues for research:

• Conformation-specific antibodies:

  • Develop antibodies that specifically recognize active versus inactive conformations of NPY2R, allowing researchers to directly assess receptor activation states in situ.

  • This would enable visualization of where in the cell or tissue the receptor is actively signaling.

• Nanobody-based detection:

  • Engineer NPY2R-specific nanobodies (single-domain antibody fragments) that offer improved tissue penetration and recognition of epitopes inaccessible to conventional antibodies.

  • Their smaller size may allow better access to sterically hindered epitopes in the GPCR structure.

• Proximity-based receptor activation sensors:

  • Develop FRET or BRET-based biosensors incorporating NPY2R antibody fragments to monitor receptor conformational changes and protein interactions in real-time in living cells.

  • This would provide temporal information about receptor activation dynamics.

• Multiplexed epitope detection:

  • Implement multiplexed detection systems that simultaneously target multiple epitopes on NPY2R to increase specificity and provide internal validation.

  • This could help distinguish NPY2R from closely related receptors like NPY1R and NPY5R.

• Receptor interactome mapping:

  • Develop proximity labeling approaches using NPY2R antibodies to map the receptor's protein interaction network in specific cellular contexts.

  • This would provide functional context to receptor expression patterns.

How might NPY2R antibodies facilitate the development of targeted therapies for neuroblastoma?

NPY2R antibodies could significantly contribute to neuroblastoma therapeutic development through several innovative approaches:

• Patient stratification biomarkers:

  • Develop standardized immunohistochemical protocols using validated NPY2R antibodies to identify patients most likely to benefit from Y2R-targeted therapies.

  • Research indicates 80% of neuroblastoma cases show positive Y2R immunostaining, suggesting potential for targeted therapy in a large subset of patients .

• Antibody-drug conjugates (ADCs):

  • Engineer therapeutic ADCs by conjugating cytotoxic payloads to NPY2R-targeting antibodies, enabling specific delivery of chemotherapy to NPY2R-expressing neuroblastoma cells.

  • The dual expression of Y2R in both tumor cells and tumor vasculature makes this approach particularly promising .

• Bispecific antibodies:

  • Develop bispecific antibodies that simultaneously target NPY2R and immune effector cells to redirect immune responses against neuroblastoma cells.

  • This approach could combine Y2R targeting with immunotherapy approaches.

• Companion diagnostics:

  • Employ NPY2R antibodies as companion diagnostics for Y2R antagonist therapies, monitoring receptor expression before and during treatment.

  • Research has demonstrated that Y2R antagonist significantly inhibits growth of neuroblastoma xenografts, supporting the development of such targeted therapies .

• Theranostic applications:

  • Develop dual-purpose NPY2R antibodies conjugated to both imaging agents and therapeutic moieties, allowing simultaneous visualization and treatment of neuroblastoma.

  • This would enable real-time monitoring of drug delivery and response.

What research questions remain unanswered regarding NPY2R function in normal physiology and disease states?

Despite significant advances, several important questions about NPY2R remain to be addressed:

• Receptor heterogeneity and isoforms:

  • How do potential NPY2R splice variants or post-translationally modified forms differ in their functional properties and antibody epitope accessibility?

  • Are certain NPY2R modifications associated with particular disease states or cellular contexts?

• Receptor trafficking dynamics:

  • How is NPY2R expression regulated at the transcriptional, translational, and post-translational levels in different cell types?

  • What mechanisms control receptor internalization, recycling, and degradation, and how might these be altered in disease states?

• Signaling pathway selectivity:

  • How does NPY2R couple to different G-protein subtypes or non-G-protein effectors in different cellular contexts?

  • Research has established connections to the p44/42 MAPK pathway in neuroblastoma, but other signaling pathways may be relevant in different contexts .

• Cross-talk with other receptor systems:

  • How does NPY2R interact functionally with other neurotransmitter receptors, growth factor receptors, or immune receptors?

  • Does NPY2R form heterodimers with other GPCRs, and if so, how does this affect signaling and ligand specificity?

• Therapeutic resistance mechanisms:

  • What mechanisms might lead to resistance to Y2R-targeted therapies in neuroblastoma?

  • How might combinatorial approaches targeting NPY2R alongside other pathways overcome potential resistance?

  • Research shows that co-targeting NPY and Y2R with siRNAs produces stronger growth inhibition than single targeting, suggesting potential benefits of combinatorial approaches .

Table 1: NPY2R Expression in Neuroblastoma Samples

Data compiled from immunohistochemistry and real-time RT-PCR analysis of neuroblastoma patient samples .

Table 2: Effects of Y2R Antagonism on Neuroblastoma Models

Table 3: Comparative Efficacy of Different NPY System Targeting Approaches

This data demonstrates that targeting Y2R directly with antagonists or siRNA provides advantages over targeting NPY alone, and that combined approaches may offer superior efficacy .

What are the key considerations for researchers beginning work with NPY2R antibodies?

Researchers beginning work with NPY2R antibodies should consider several key factors to ensure successful experimental outcomes:

What future developments in NPY2R research hold the most promise?

Based on current research trends, several developments in NPY2R research appear particularly promising:

• Therapeutic applications in neuroblastoma: Y2R antagonists have shown significant anti-tumor effects in preclinical models by simultaneously targeting cancer cell proliferation and tumor angiogenesis. Further development of these compounds into clinical candidates represents a promising direction for neuroblastoma therapy .

• Dual-targeting approaches: Research indicates that simultaneously targeting NPY and Y2R provides superior growth inhibition compared to single-target approaches. Development of strategies that block both ligand and receptor may offer enhanced therapeutic efficacy .

• Biomarker development: Standardized assessment of NPY2R expression in tumor samples could serve as a biomarker for patient stratification in clinical trials of Y2R-targeted therapies.

• Novel antibody technologies: Development of antibody derivatives like nanobodies or bispecific antibodies targeting NPY2R could open new therapeutic avenues.

• Expanded understanding of NPY2R signaling networks: Further elucidation of the complex signaling networks downstream of NPY2R activation, particularly the interplay between pro-proliferative and pro-apoptotic pathways, will enhance our understanding of NPY2R biology and may reveal additional therapeutic targets.