SIRPA Rat
Description
Biological Functions and Pathways
SIRPA Rat plays critical roles in diverse physiological and pathological processes:
Immune Regulation
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CD47 Binding: Acts as a receptor for CD47, modulating immune cell function and macrophage adhesion .
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Negative Signaling: ITIM motifs inhibit receptor tyrosine kinase (RTK)-coupled responses, suppressing inflammatory pathways .
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TLR4/NF-κB Axis Inhibition: Protects against cardiac hypertrophy by downregulating Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) signaling .
Cardiac Function
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Hypertrophy Modulation: SIRPA deficiency exacerbates pressure overload-induced cardiac hypertrophy and fibrosis, while overexpression mitigates these effects .
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Mechanistic Insight: Adenoviral overexpression of SIRPA in rat models reduces hypertrophic markers (e.g., ANP, BNP) and improves contractile function .
Neural Development
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Neuronal Adhesion: Supports cerebellar neuron adhesion and neurite outgrowth .
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Synaptic Function: May regulate intracellular signaling during synaptogenesis .
Research Applications and Experimental Models
SIRPA Rat has been extensively studied using recombinant proteins and genetic models:
Cardiomyopathy
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Human DCM: Reduced SIRPA expression correlates with dilated cardiomyopathy progression .
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Therapeutic Potential: SIRPA upregulation may mitigate hypertrophic remodeling .
Ocular Disorders
Gene Information
Product Specs
Q&A
What is SIRPA and what are its expression patterns in rat tissues?
SIRPA, also known as CD172A or Tyrosine-protein phosphatase non-receptor type substrate 1, is selectively expressed by myeloid and neuronal cells in rats . It functions as a regulatory protein involved in cellular signaling pathways and has been identified in rat hippocampus through proteomic studies . Understanding SIRPA's tissue distribution is essential for designing targeted experiments.
Methodological approach: For tissue-specific expression analysis, researchers should consider using immunohistochemistry with validated antibodies such as OX-41 or molecular approaches like qPCR. When analyzing various tissues, standardize sample collection protocols to minimize variability and use appropriate housekeeping genes or proteins as controls for quantification.
How can SIRPA protein be detected and quantified in rat samples?
Multiple validated antibodies are available for rat SIRPA detection, including the OX-41 clone in various formats:
Table 1: Available Antibody Formats for Rat SIRPA Detection
| Product Code | Host/Format | Modifications | Availability |
|---|---|---|---|
| Ab00553-8.1 | Rat IgG2b | Purified | Ships in 4-5 weeks |
| Ab00553-2.0 | Mouse IgG2a | Purified | In Stock |
| Ab00553-2.3 | Mouse IgG2a | Fc Silent™ | In Stock |
| Ab00553-8.4 | Rat IgG2b | Fc Silent™ | Ships in 4-5 weeks |
| Ab00553-23.0 | Rabbit IgG | Purified | In Stock |
Methodological approach: For robust protein quantification, western blotting with chemiluminescence detection offers good sensitivity. Standard curves using recombinant rat SIRPA protein can provide absolute quantification. For relative quantification, normalize SIRPA levels to consistently expressed housekeeping proteins. Mass spectrometry offers an antibody-independent alternative, as successfully employed in proteomic studies identifying SIRPA in rat hippocampus .
How does SIRPA expression change under experimental conditions in rat models?
Studies have shown that SIRPA expression is sensitive to experimental manipulations. For instance, in simulated microgravity experiments using tail suspension, SIRPA protein was significantly downregulated in rat hippocampus (fold change: 0.62, p=0.008158) . This suggests SIRPA may be involved in stress-responsive pathways affecting neuronal function.
Methodological approach: When designing experiments to monitor SIRPA expression changes, include appropriate time-course analyses, as expression changes may be transient. Compare results across multiple detection methods (protein and mRNA) to distinguish between transcriptional and post-transcriptional regulation. Statistical analysis should employ appropriate tests based on data distribution, as demonstrated in the microgravity study which used Student's t-test for comparison between control and experimental groups .
What genetic engineering approaches are suitable for SIRPA modification in rats?
While not specific to SIRPA, advanced genetic engineering techniques have been developed that could be applied to SIRPA gene modification in rats:
Table 2: Genetic Engineering Methods Applicable to SIRPA Modification
| Method | Description | Applications for SIRPA |
|---|---|---|
| CRISPR-Cas systems | Introduces targeted DNA breaks via Cas9 and gRNA | SIRPA gene knockout; short sequence modifications |
| lsODN | Long single-stranded oligodeoxynucleotide method | Efficient knock-in of larger DNA sequences |
| 2H2OP | Two-hit two-oligo with plasmid technique | Introduction of large genomic regions; potential for humanized SIRPA rats |
These methods have demonstrated efficiency in modifying genes in rats and could enable precise genetic manipulation of SIRPA .
Methodological approach: For CRISPR-based SIRPA knockout, design multiple gRNAs targeting early exons of the rat SIRPA gene to increase success rates. Validate modifications through genomic sequencing and confirm protein absence via western blotting or immunohistochemistry. For knock-in applications, ensure homology arms are properly designed for the SIRPA locus.
What role does SIRPA play in rat hippocampal function?
SIRPA has been identified in rat hippocampal mitochondrial proteome, suggesting involvement in mitochondrial function in hippocampal neurons . Under simulated microgravity conditions, which affect cognitive function, SIRPA was downregulated concurrently with increased mitochondrial number and size in hippocampal neuronal soma . This correlation suggests SIRPA may contribute to mitochondrial dynamics and hippocampal adaptation to environmental stressors.
Methodological approach: To investigate SIRPA's neurobiological functions, researchers should combine molecular approaches with behavioral testing. Spatial learning and memory tests (e.g., Morris water maze) combined with SIRPA expression analysis can reveal correlations between cognitive performance and SIRPA levels. For mechanistic insights, consider using primary hippocampal neuron cultures with SIRPA manipulation followed by mitochondrial function assessment.
How might SIRPA be involved in neurological disorders modeled in rats?
While direct evidence from the search results is limited, the downregulation of SIRPA in rat hippocampus under stress conditions suggests potential relevance to neurological disorders . The authors note that "neuropathological characteristics of animal simulated microgravity model can be comparable to the effects of aging, anxiety and other neurological diseases" .
Methodological approach: Researchers should incorporate SIRPA analysis into established rat models of neurological disorders. For instance, in aged rat models, compare SIRPA expression between young and aged animals across brain regions. In anxiety models, correlate SIRPA levels with behavioral measures. Consider pharmacological interventions targeting pathways involving SIRPA to assess potential therapeutic relevance.
What are the safety considerations for targeting SIRPA in rat models?
Methodological approach: When testing SIRPA-targeting compounds, adopt similar safety assessment protocols including:
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Dose-ranging studies starting with low concentrations
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Comprehensive clinical observations
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Histopathological examination of tissues expressing SIRPA
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Monitoring for both acute and delayed adverse effects
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Assessment of immune parameters given SIRPA's expression in myeloid cells
How should researchers design rat feeding studies that might affect SIRPA expression?
While not directly addressing SIRPA, search result describes a 90-day rat feeding study with genetically modified maize, providing a methodological framework that could be adapted for studies where dietary interventions might affect SIRPA expression.
Methodological approach: Design feeding studies with appropriate controls, sufficient sample sizes for statistical power, and standardized housing conditions. Consider the environmental enrichment protocol outlined in result as a potential variable, as enrichment might influence neurological parameters including SIRPA expression. Monitor SIRPA in relevant tissues at multiple timepoints, as expression changes might be time-dependent.
How can environmental enrichment protocols be utilized to study SIRPA regulation?
Environmental enrichment (EE) represents a promising approach for studying SIRPA regulation in rats, particularly in neurological contexts. The detailed EE protocol described in result provides a standardized method that could be applied to investigate SIRPA expression changes.
Methodological approach: Implement the protocol as described, including:
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Appropriate cage setup with stimulatory objects
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Scheduled EE sessions
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Proper animal identification through tail marking
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Control groups housed in standard conditions
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Sample collection from brain regions known to express SIRPA
Compare SIRPA protein and mRNA levels between enriched and standard-housed rats, correlating expression with cognitive or behavioral measures.
What is the potential for SIRPA humanization in rat models for translational research?
The genetic engineering techniques described in result have successfully replaced rat genes with human-derived genes. This approach could be applied to create SIRPA-humanized rat models for translational research, particularly valuable for testing therapeutic approaches targeting human SIRPA.
Methodological approach: Utilize the 2H2OP (two-hit two-oligo with plasmid) technique to replace rat SIRPA with the human ortholog . Confirm humanization at genomic, transcript, and protein levels. Characterize the phenotype comprehensively, particularly in systems where SIRPA functions (neuronal and immune). Use these models to test human-specific SIRPA-targeting compounds for potential therapeutic applications.
Product Science Overview
SIRPα was initially cloned as a substrate for Src homology region 2 (SH2) domain-containing phosphatase-1 (SHP-1) and SHP-2 . These are cytoplasmic-type protein tyrosine phosphatases, and SIRPα was initially termed SHPS-1 (SHP substrate-1) . It was also named as brain immunoglobulin (Ig)-like molecule with tyrosine-based activation motifs (BIT), macrophage fusion receptor (MFR), and MyD-1 .
The extracellular region of SIRPα consists of three immunoglobulin-like domains . The cytoplasmic region comprises tyrosine residues with immunoreceptor tyrosine-based inhibitory motifs (ITIMs), which activate SHP-1 and SHP-2, mediating the specific biological function of SIRPα . The intracellular region also binds adaptor molecules such as Src kinase-associated phosphoprotein 2 (SKAP2) and Fyn-binding protein/SLP-76-associated phosphoprotein of 130 kDa (FYB/SLAP-130), as well as the tyrosine kinase PYK2 .
SIRPα is especially expressed on neurons, pancreatic β cells, and myeloid lineage cells such as macrophages, dendritic cells, and neutrophils . Other cell types, such as fibroblasts and endothelial cells, also express SIRPα, but at lower levels . CD47, the ligand for SIRPα, is expressed in most cell types .
The interaction between SIRPα and CD47 plays a crucial role in the regulation of immune responses. SIRPα acts as an inhibitory receptor, and its interaction with CD47 helps to prevent the phagocytosis of healthy cells by macrophages . This interaction is essential for maintaining self-tolerance and preventing autoimmune responses .
SIRPα is involved in various biological processes, including cell adhesion, leukocyte migration, and the regulation of protein phosphorylation . It also plays a role in the regulation of gene expression, cell migration, and the production of cytokines such as interferon-gamma, interleukin-1 beta, interleukin-6, and tumor necrosis factor . Additionally, SIRPα is involved in the negative regulation of inflammatory responses and phagocytosis .
Recombinant SIRPα (rat) is a form of the protein that has been produced using recombinant DNA technology. This allows for the production of large quantities of the protein for research and therapeutic purposes. Recombinant SIRPα is used in various studies to understand its function and interaction with CD47, as well as its role in immune regulation and potential therapeutic applications.
