APLN Antibody
Product Specs
Target Background
Apelin-36 is an endogenous ligand for the apelin receptor (APLNR). It induces APLNR internalization and exhibits stronger binding affinity to APLNR compared to pyroglutamyl apelin-13. This hormone plays a crucial role in regulating cardiac precursor cell migration during gastrulation and heart morphogenesis. Apelin-36 inhibits cytokine production in response to T-cell receptor/CD3 cross-linking, suggesting a potential modulatory effect on neonatal immune responses via colostrum and milk intake. It is involved in early coronary blood vessel development and mediates myocardial contractility through an ERK1/2-dependent mechanism. Additionally, apelin-36 may influence central body fluid homeostasis by affecting vasopressin release and drinking behavior. In the context of microbial infection, apelin-36 acts as an endogenous ligand for APLNR, serving as an alternative coreceptor with CD4 for HIV-1 infection. It significantly inhibits HIV-1 entry into cells co-expressing CD4 and APLNR, exhibiting greater inhibitory activity than other apelin derivatives.
The following studies highlight the diverse roles and clinical implications of apelin:
- Lower apelin serum levels are observed in hemodialysis patients with pulmonary arterial hypertension, independent of hemodialysis effects. PMID: 30087215
- Apelin is associated with reduced pressure pulsatility in rheumatoid arthritis patients with low inflammatory burden. PMID: 29423718
- Apelin exhibits therapeutic potential in conditions such as insulin resistance and hypertension, but may also have detrimental effects in certain contexts. PMID: 29750964
- The V103V polymorphism in the APLN gene increases the risk of coronary artery disease in patients with acute obstructive coronary syndrome. PMID: 28902642
- Circulating chemerin, apelin, vaspin, and omentin-1 levels are correlated with coronary artery stenosis in obese type 2 diabetic patients, suggesting their potential as diagnostic biomarkers. PMID: 28957639
- Apelin/APJ signaling in hepatocytes protects against hepatic lipid accumulation via AMPK activation and PPARα induction. PMID: 28821440
- The apelin/APJ system may offer therapeutic potential in cancer treatment by regulating apoptosis. PMID: 28407045
- miR-497 contributes to oxLDL-induced lipid deposition in macrophages by targeting apelin. PMID: 28653788
- High APLN levels predict poor response to bevacizumab therapy in colorectal cancer patients. PMID: 28487489
- Serum apelin levels are not associated with increased odds of severe hypertension. PMID: 26869250
- Apelin-12 influences troponin I levels in acute ST-segment elevation myocardial infarction (STEMI), while low apelin levels in the non-acute phase correlate with a high rate of major adverse cardiac events (MACE). PMID: 28728608
- Apelin concentrations are associated with altered plaque stability mediator levels and atherosclerosis in rheumatoid arthritis patients, with influences from population origin and inflammatory status. PMID: 28017911
- APLN and APLNR are expressed in human ovarian cells, and APLN enhances IGF1-induced steroidogenesis in granulosa cells, potentially influencing follicular development and polycystic ovary syndrome (PCOS). PMID: 27683264
- Apelin levels reflect cardiovascular changes during pregnancy and are reduced in intrauterine growth restriction. PMID: 26880769
- Reduced apelin levels may contribute to vasoconstriction, influencing hypertension and cardiac workload. PMID: 27543713
- Tumor apelin serves as a prognostic marker in gastric cancer patients. PMID: 27733135
- The apelin/APLNR axis regulates cholangiocarcinoma cell proliferation and tumor angiogenesis. PMID: 27894959
- Plasma apelin increases with obesity but decreases with age and pubertal stage. PMID: 24896245
- Increased plasma apelin is associated with ST-segment elevation acute myocardial infarction (STEMI) severity. PMID: 27889567
- Apelin/APJ signaling contributes to sprout extension through a self-generated gradient mechanism. PMID: 27828952
- Postmenopausal breast cancer patients exhibit high apelin levels and high BMI. PMID: 28039702
- Prolylcarboxypeptidase (PRCP) is identified as an apelin-cleaving enzyme. PMID: 27449720
- APLN and APLNR gene polymorphisms may influence hypertension susceptibility. PMID: 27450650
- Serum apelin levels do not differ significantly between patients with atrial fibrillation and coronary artery disease. PMID: 27776716
- Initial apelin-12 levels predict major adverse coronary events in ST-elevation myocardial infarction patients. PMID: 27770057
- Six-month CT-apelin is a superior biomarker to NT-proBNP in identifying non-responders to cardiac resynchronization therapy. PMID: 27471876
- High ACE and low apelin preoperatively correlate with increased CRP and MDA postoperatively, potentially linking to postoperative atrial fibrillation after off-pump coronary artery bypass grafting. PMID: 28299332
- Single nucleotide polymorphisms (SNPs) in the Apelin gene are associated with diabetes mellitus. PMID: 27831922
- Bisphenol A upregulates apelin, promoting ovarian cancer cell progression. PMID: 28111160
- APLN expression is upregulated in human masticatory mucosa during wound healing. PMID: 28005267
- Gene polymorphisms in the apelin-APJ system are associated with hypertension susceptibility. PMID: 27338090
- Lower apelin and higher visfatin plasma levels in individuals with high-normal blood pressure suggest a higher cardiovascular risk. PMID: 26276791
- Elevated apelin-13 levels are observed in patients with pulmonary embolism (PE), suggesting its potential as a biomarker and therapeutic target. PMID: 25693918
- Upregulation of apelin and APJ expression contributes to cardioprotection against myocardial ischemia/reperfusion injury. PMID: 27854125
- No significant change in plasma apelin levels is observed in acute pulmonary embolism. PMID: 26968282
- Lower levels of gastric peptides (ghrelin and obestatin) and adipocytokines (omentin and apelin) are observed in individuals with specific disease subgroups. PMID: 26904686
- Five APLN variants were identified through apelin gene resequencing, with no association found between the most frequent variant, diabetes, and metabolic parameters. PMID: 26789934
- Apelin/APLNR signaling may represent a therapeutic target for hypoxic/ischemic injury. PMID: 26676468
- Apelin attenuates osteoblastic differentiation of aortic valve interstitial cells via the ERK and PI3-K/Akt pathway. PMID: 26142632
- Genetic variants in the apelin gene are associated with coronary artery disease risk in the Turkish population. PMID: 25592107
- Apelin activates multiple protective mechanisms against ischemia/reperfusion injury in the heart, brain, liver, and kidney. PMID: 25447414
- Apelin and APLN SNP rs3761581 are associated with combined hypertension and coronary artery disease (CRAE), suggesting involvement in vascular injury. PMID: 25272042
- Hypoxia upregulates apelin and APJ expression via the hypoxia-inducible factor-1 alpha (HIF-1α) signaling pathway. PMID: 26436483
- Lower serum apelin levels are observed in obese children, particularly those with diabetes; the G212A polymorphism in the APLNR gene may favorably influence apelin levels in childhood obesity. PMID: 25060841
- Apelin interferes with thrombin-mediated platelet activation, secretion, and aggregation. PMID: 26634301
- Apelin may serve as an indicator of vessel normalization during antiangiogenic therapy. PMID: 26475217
- Lower mean vaspin and apelin levels are observed in underweight children compared to controls. PMID: 25915077
- Metformin and vildagliptin favorably affect glycemic indices and apelin levels in type 2 diabetes patients. PMID: 26316706
- Elevated serum apelin is observed in new-onset diabetes after transplant, correlating with proteinuria. PMID: 26295182
- Apelin-13 promotes MCF-7 cell proliferation and invasion via the ERK1/2/AIB1 signaling pathway. PMID: 26135903
Q&A
How do I validate the specificity of an APLN antibody for my experimental system?
Validation requires a multi-step approach grounded in the "five pillars" framework :
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Genetic strategies: Use APLN knockout (KO) cell lines or tissues as negative controls. Reduced/no signal in KO samples confirms specificity .
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Orthogonal validation: Compare antibody-derived data with mass spectrometry or RNA-seq results .
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Independent antibody comparison: Use ≥2 antibodies targeting different APLN epitopes (e.g., N-terminal vs C-terminal) .
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Recombinant protein controls: Spike purified APLN into lysates to confirm expected band patterns in Western blots .
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Context-specific testing: Validate in your specific model (e.g., human diabetic testes vs murine cardiac tissue ).
Table 1: Key Validation Metrics for APLN Antibodies
What experimental factors determine optimal APLN antibody selection for Western blot vs immunohistochemistry?
Western blot:
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Use antibodies validated for linear epitopes (e.g., ab230536 targeting C-terminal residues ).
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Optimize lysis buffers to preserve APLN's small size (8.6 kDa ); avoid over-boiling to prevent aggregation .
Immunohistochemistry:
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Prioritize antibodies with formalin-resistant epitopes (e.g., ab59469 ).
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Pre-treat sections with enzymatic retrieval for mature APLN isoforms (e.g., Apelin-36 ).
Methodological considerations:
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Fixation artifacts: Overfixation masks APLN epitopes; limit formalin exposure to <24 hrs .
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Blocking: Use 5% BSA + 0.1% Tween-20 to reduce non-specific binding in fatty tissues .
How do I confirm APLN antibody cross-reactivity in non-mammalian models?
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Sequence alignment: Compare target epitope against species homologs (e.g., zebrafish APLN shares 64% identity with human ).
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Functional testing: Perform peptide blocking assays with species-specific APLN fragments .
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Negative controls: Include tissues from APLN-deficient models (e.g., Apln KO mice ).
Case example:
PA1501 antibody showed unexpected reactivity in goat tissues despite lacking prior validation, necessitating epitope mapping .
What methods reliably distinguish between APLN isoforms (e.g., Apelin-13 vs Apelin-36)?
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Electrophoresis: Use Tris-Tricine gels for improved resolution of small isoforms (3-12 kDa ).
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Antibody pairing: Combine N-terminal (ab59469 ) and C-terminal (ab230536 ) antibodies.
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LC-MS/MS: Confirm isoform identity after immunoprecipitation .
Isoform-specific challenges:
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Apelin-13 has higher receptor affinity but lower stability than Apelin-36 .
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Commercial antibodies often recognize shared epitopes; isoform-specific reagents require custom development .
How do I resolve contradictions in APLN localization data across studies?
Common sources of discrepancy:
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Post-translational modifications: APLN cleavage varies by tissue (e.g., hypothalamic vs testicular isoforms ).
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Antibody lot variation: Recombinant antibodies (e.g., YCharOS products ) reduce batch effects.
Mitigation strategies:
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Perform parallel staining with RNAscope® probes to correlate protein/transcript localization .
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Use pathway perturbation: Treat cells with APJ antagonists (ML221) to validate functional relevance of staining patterns .
What explains divergent APLN-mediated effects in vivo vs in vitro models?
Key variables:
Experimental design solution:
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Use organotypic co-cultures (e.g., myotubes + endothelia ) to bridge the gap.
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Employ tracer perfusion assays in vivo (e.g., biotin diffusion in testes ).
How can APLN antibody data be integrated with metabolomic/proteomic datasets?
Multi-omics workflow:
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Immunoprecipitation: Isolate APLN complexes using crosslinkers (DSS).
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Metabolite correlation: Map APLN levels against NAD⁺/glutathione (perturbed in diabetic models ).
Table 2: APLN-associated metabolites in Sertoli cells
| Metabolite | Change (APLN-treated vs control) | Pathway implication |
|---|---|---|
| NAD⁺ | ↓ 62% | Redox imbalance |
| Palmitelaidic acid | ↑ 4.1-fold | Membrane dysfunction |
What controls are essential when studying APLN in disease models (e.g., diabetes)?
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Disease-specific controls:
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Antibody controls:
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Functional endpoints:
