BMP7 Antibody

What is BMP7 and what are its primary biological functions?

BMP7 (Bone Morphogenetic Protein 7), also known as osteogenic protein-1 (OP-1), is a growth factor belonging to the TGF-beta superfamily. It plays crucial roles in various biological processes including:

• Embryogenesis, hematopoiesis, neurogenesis, and skeletal morphogenesis

• Langerhans cell differentiation and proliferation in the epidermis during prenatal development

• Brown adipocyte differentiation and thermogenesis through non-canonical signaling pathways

• Antifibrotic activity in multiple tissues (kidney, lung, liver, heart, peritonium, oral submucosa, and colonic wall)

• Cancer progression and resistance to immunotherapy in certain contexts

BMP7 initiates the canonical BMP signaling cascade by associating with type I receptor ACVR1 and type II receptor ACVR2A. Once bound together at the cell surface, ACVR2A phosphorylates and activates ACVR1, which propagates the signal by phosphorylating SMAD1/5/8. These SMADs then travel to the nucleus and regulate transcription of target genes .

How does BMP7 signaling differ from other BMP family members?

BMP7 has several distinctive signaling characteristics:

• For specific functions such as growth cone collapse in developing spinal neurons and chemotaxis of monocytes, BMP7 utilizes BMPR2 as a type II receptor

• Unlike some other BMPs, BMP7 can signal through non-canonical pathways such as the P38 MAP kinase signaling cascade, which promotes brown adipocyte differentiation through activation of target genes including members of the SOX family of transcription factors

• In comparative studies, only BMP4 (not BMP2 or BMP6) could replace BMP7 in inducing Langerhans cell differentiation, suggesting unique receptor binding properties

• While TGF-β1 induces phosphorylation of both Smad2/3 and Smad1/5/8, BMP7 results exclusively in Smad1/5/8 phosphorylation

This signaling specificity explains why BMP7 can antagonize certain TGF-β1 effects, particularly in fibrosis and epithelial-mesenchymal transitions.

What criteria should researchers use when selecting BMP7 antibodies for different applications?

When selecting a BMP7 antibody, consider the following factors:

It's essential to select antibodies validated for your particular application and experimental system. For instance, some BMP7 antibodies are only sensitive enough to detect transfected/overexpressed protein rather than endogenous levels .

What are the optimal dilutions and conditions for detecting BMP7 across different applications?

Based on validated protocols across multiple antibody sources:

It's recommended to titrate antibodies for each specific experimental system to achieve optimal results. Different tissues and sample preparation methods may require protocol adjustments .

How can researchers validate BMP7 antibody specificity and troubleshoot common detection issues?

Comprehensive BMP7 antibody validation should include:

• Positive and negative controls:

  • Use tissues/cells with known BMP7 expression (kidney, MCF-7, HEK-293 cells)

  • Include negative controls (isotype antibodies, tissues with low expression)

• Molecular weight verification:

  • BMP7 has a calculated molecular weight of 49 kDa (431 amino acids)

  • Observed molecular weight typically ranges from 43-49 kDa depending on post-translational modifications

• Cross-reactivity testing:

  • Test for cross-reactivity with other BMP family members, especially BMP-6

  • Perform blocking peptide competitions to confirm specificity

• Application-specific validations:

  • For IHC: Compare staining patterns with published literature

  • For WB: Confirm single band at expected molecular weight

  • For neutralization: Verify inhibition of BMP7-induced alkaline phosphatase production

• Troubleshooting low detection:

  • Consider sample preparation (BMP7 is secreted; analyze both cell lysates and media)

  • Optimize antigen retrieval for IHC (TE buffer pH 9.0 recommended)

  • Use enhancement methods (signal amplification, increased protein loading)

  • For some antibodies, only transfected/overexpressed BMP7 may be detectable

How are BMP7 antibodies utilized in cancer research, particularly regarding metastasis and immunotherapy?

BMP7 antibodies have become essential tools in cancer research:

• Expression profiling and biomarker development:

  • IHC analysis reveals that BMP7 is confined to differentiated colorectal cancer cells rather than cancer stem cells

  • BMP7 expression correlates with pathological grading in colorectal cancer tissue microarrays

  • Differential expression patterns help identify potential biomarkers for therapeutic response

• Mechanistic studies of metastasis:

  • BMP7 is upregulated in some cancer cells and may play a role in cancer metastasis

  • Antibodies enable tracking of BMP7 expression changes during metastatic progression

• Immunotherapy resistance:

  • BMP7 overexpression represents a mechanism for resistance to anti-PD1 therapy in preclinical models

  • BMP7 secreted by tumor cells acts on macrophages and CD4+ T cells in the tumor microenvironment, inhibiting MAPK14 expression and impairing pro-inflammatory responses

  • Neutralizing antibodies allow experimental testing of whether BMP7 inhibition restores sensitivity to immunotherapy

• Therapeutic approaches:

  • Knockdown of BMP7 or its neutralization via follistatin in combination with anti-PD1 re-sensitizes resistant tumors to immunotherapies

  • Combinations with other therapeutic agents (PI3K inhibitors, chemotherapy) show promising results in preclinical studies

These applications demonstrate the critical role of BMP7 antibodies in understanding cancer progression mechanisms and developing new therapeutic strategies.

What role do BMP7 antibodies play in studying fibrosis inhibition mechanisms?

BMP7 antibodies are crucial tools for investigating antifibrotic mechanisms:

• Antagonism of TGF-β1-induced fibrosis:

  • BMP7 has been identified as an anti-fibrotic molecule that directly antagonizes TGF-β1

  • While TGF-β1 induces both Smad2/3 and Smad1/5/8 phosphorylation, BMP7 exclusively activates Smad1/5/8

  • Differential receptor expression may explain opposing effects: BMP7-generated cells show higher ALK3 expression than ALK5, while TGF-β1-generated cells show the inverse pattern

• Preservation of cellular phenotypes:

  • BMP7 preserves the endothelial phenotype when TGF-β1 would induce endothelial-mesenchymal transition (EndMT)

  • Antibodies help visualize how BMP7 maintains epithelial marker expression in cells exposed to fibrogenic stimuli

• Tissue-specific antifibrotic activities:

  • BMP7 inhibits fibrosis in multiple tissues: kidney, lung, liver, heart, peritoneum, oral submucosa tissue, and colonic wall

  • IHC with BMP7 antibodies helps map expression patterns in normal versus fibrotic tissues

• Therapeutic development:

  • Antibodies enable assessment of BMP7 as a potential therapeutic target

  • Neutralizing antibodies allow experimental manipulation of endogenous BMP7 signaling

  • Recombinant BMP7 effects can be confirmed through antibody-based detection of downstream signaling activation

This research area represents a promising direction for developing therapies for fibrotic diseases, with BMP7 antibodies providing essential tools for mechanistic understanding.

How can researchers optimize BMP7 detection in challenging experimental systems?

For challenging experimental systems, consider these advanced optimization strategies:

• Low endogenous expression scenarios:

  • Perform immunoprecipitation before Western blotting to concentrate BMP7

  • Use signal enhancement systems (amplified detection chemistries)

  • Consider alternative detection methods (ELISA) for quantitative analysis

  • For some antibodies, sensitivity is limited to "Transfected Only" detection

• Complex tissue samples:

  • For IHC, compare different antigen retrieval methods (TE buffer pH 9.0 vs. citrate buffer pH 6.0)

  • Extend primary antibody incubation (overnight at 4°C instead of shorter incubations)

  • Use amplification systems for chromogenic or fluorescent detection

  • Consider background reduction techniques (Sudan Black B for autofluorescence)

• Secreted protein considerations:

  • Analyze both cell lysates and conditioned media

  • Use protein concentration methods for media samples

  • Add protease inhibitors during sample preparation

  • Consider the timing of collection (BMP7 accumulation in media)

• Multiple detection approaches:

  • Combine different applications (WB, IHC, IF) for comprehensive analysis

  • Use antibodies targeting different epitopes to confirm results

  • Correlate protein detection with mRNA expression data

  • Consider functional readouts (Smad1/5/8 phosphorylation) alongside direct BMP7 detection

These strategies can significantly improve detection sensitivity and specificity in challenging experimental contexts.

How are BMP7 antibodies being applied in developmental biology and stem cell research?

BMP7 antibodies are enabling new insights in developmental and stem cell research:

• Langerhans cell differentiation:

  • BMP7 promotes the differentiation of Langerhans cells in the epidermis during prenatal development

  • BMP7 exceeds TGF-β1 in promoting Langerhans cell generation, correlating with positive role of ALK3 in differentiation

  • Antibodies help track lineage commitment and differentiation patterns

• Brown adipocyte differentiation:

  • BMP7 promotes brown adipocyte differentiation through non-canonical P38 MAP kinase signaling

  • Antibodies allow visualization of BMP7 distribution in adipose tissue depots

  • Neutralizing antibodies can experimentally manipulate differentiation processes

• Stem cell fate decisions:

  • In colorectal cancer, BMP7 is confined to differentiated cells rather than LGR5+ stem cells

  • Differential receptor expression (ALK3 vs. ALK5) influences cell fate decisions

  • Antibodies help map spatial distribution of BMP7 in stem cell niches

• Organ development:

  • During embryogenesis, BMP7 contributes to heart, neural, and cartilage development

  • Antibodies enable temporal and spatial mapping of BMP7 expression during organogenesis

This research provides fundamental insights into developmental processes and potential applications in regenerative medicine.

What methodological considerations are important when using BMP7 antibodies in multiplexed detection systems?

When incorporating BMP7 antibodies into multiplexed detection systems:

• Antibody compatibility:

  • Ensure primary antibodies are from different host species to avoid cross-reactivity

  • If using multiple rabbit antibodies, consider sequential detection with complete stripping between rounds

  • Verify that detection systems (fluorophores, chromogens) have minimal spectral overlap

• Epitope accessibility:

  • Optimize antigen retrieval conditions that work for all target proteins

  • Consider the order of antibody application in sequential protocols

  • Test for potential epitope masking between antibodies

• Signal separation:

  • For fluorescence multiplexing, choose fluorophores with well-separated excitation/emission spectra

  • For chromogenic multiplexing, select contrasting colors (e.g., red BMP7 staining with blue/brown counterstains)

  • Use spectral unmixing for closely related fluorophores

• Controls and validation:

  • Include single-stained controls to verify specificity in the multiplex context

  • Use colocalization analysis to quantify genuine overlap versus background

  • Consider automated analysis tools to quantify multiplex data objectively

• Recommended combinations:

  • BMP7 (green) with LGR5 (red) has been successfully used for colorectal cancer tissue analysis

  • BMP7 (red) with nuclear counterstains (hematoxylin, blue) works well for assessing expression patterns

  • CD31/VEGFR2 markers with BMP7 for assessing relationships with angiogenesis

These considerations ensure reliable data generation in complex multiplexed detection systems.

How should researchers design BMP7 neutralization experiments using antibodies?

For effective BMP7 neutralization studies:

• Antibody selection:

  • Choose antibodies specifically validated for neutralization (e.g., clone 164311)

  • Verify the neutralization dose (ND50) under your experimental conditions

  • For the anti-human BMP7 monoclonal antibody, typical ND50 is 1.5-6.0 μg/mL in the presence of L-ascorbic acid (50 μg/mL)

• Experimental design:

  • Include dose-response curves to determine optimal neutralization concentration

  • Pre-incubate antibodies with BMP7 before cell treatment when testing direct inhibition

  • Include appropriate controls (isotype antibodies, irrelevant neutralizing antibodies)

• Functional readouts:

  • Alkaline phosphatase production in ATDC5 mouse chondrogenic cells is a validated BMP7-dependent process for neutralization assays

  • Smad1/5/8 phosphorylation provides a direct measure of canonical BMP7 signaling inhibition

  • Cell-type specific responses (differentiation, migration, etc.) offer contextual functional measures

• Combination approaches:

  • Consider combining BMP7 neutralization with other pathway modulators (e.g., PI3K inhibitors)

  • For immunotherapy resistance, combine BMP7 neutralization with checkpoint inhibitors

  • Alternative neutralization strategies (follistatin, receptor inhibitors) can complement antibody approaches

• Limitation considerations:

  • Account for potential cross-neutralization of other BMPs (particularly BMP-6)

  • Consider the half-life of neutralizing antibodies in long-term experiments

  • Be aware of potential compensatory upregulation of other BMP family members

Properly designed neutralization experiments provide powerful insights into BMP7's functional roles in various biological processes.