Recombinant Human Thymic stromal lymphopoietin protein (TSLP) (Active)
Description
Molecular Structure and Isoforms
Recombinant human TSLP is produced in either E. coli or HEK293 cells, yielding distinct isoforms:
Two isoforms exist naturally:
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lfTSLP (long form): Expressed in heart, liver, and prostate (159 aa).
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sfTSLP (short form): Expressed in keratinocytes and mucosal tissues (63 aa) .
Key Functions
TSLP activates immune cells via the TSLPR/IL-7Rα receptor complex, leading to:
Signaling Pathways
TSLP activates STAT3/STAT5 and MAPK pathways (ERK, p38, JNK) independently of JAK kinases .
Production Systems
| System | Advantages | Limitations |
|---|---|---|
| E. coli | High yield, cost-effective | Non-glycosylated; reduced bioactivity? |
| HEK293 | Glycosylated; native folding | Lower yield; higher production costs |
Purification Methods
Experimental Uses
Therapeutic Targets
Product Specs
Target Background
- TSLP receptor allosterically activates TSLP to potentiate the recruitment of the shared interleukin 7 receptor alpha-chain (IL-7Ralpha) by leveraging the flexibility, conformational heterogeneity, and electrostatics of the cytokine. PMID: 28368013
- Effects of Linalyl Acetate on Thymic Stromal Lymphopoietin Production in Mast Cells. PMID: 30011850
- The presence of epithelium-derived TSLP in the eustachian tubes plays a significant role in the onset of eosinophilic otitis media. PMID: 29272985
- A new mechanism of T cell stimulation in human skin has been identified, demonstrating the direct induction of T cell migration by TSLP in the absence of DCs. PMID: 28377574
- The secretion of TSLP by keratinocytes is induced by the HIV-1 viral synapse in a miR-375 controlled manner. PMID: 28443609
- TSLP production is increased at skin sites of ovalbumin sensitization. PMID: 27992078
- Sera of patients with infantile eosinophilic gastroenteritis showed a specific increase in both thymic stromal lymphopoietin and IL-33 levels. PMID: 26948075
- Short and long thymic stromal lymphopoietin isoforms have roles in house dust mite-induced asthmatic airway epithelial barrier disruption. PMID: 27996052
- DeltaNp73 was abundantly expressed in the atopic dermatitis epidermis and increased the release of TSLP via NF-kappaB activation. PMID: 28655470
- This study shows that the long form of thymic stromal lymphopoietin of keratinocytes is induced by protein allergens. PMID: 28720058
- We discovered that activation of the protease-activated receptor 1 (PAR1) induced secretion of TSLP by the corneal stromal cells... We propose that TSLP may function as the link between increased protease activity and inflammatory responses or itch sensation in the corneas. PMID: 28631887
- The TSLP-HOTAIR axis also plays a protective role in low-density lipoprotein (ox-LDL)-induced endothelial cells' injury. PMID: 28615347
- This study aimed to determine the influence of human rhinovirus on the genes involved in airway remodeling and to examine the impact of TSLP and the contribution of oxidative stress on airway remodeling in the context of HRV infection. PMID: 28545810
- TSLP-induced phosphorylation of l-plastin is increased in atopic dermatitis and increases eosinophil migration. PMID: 27304220
- A hit expansion exercise yielded additional active compounds that could be amenable to further optimization, providing an opportunity to dissociate TSLP inhibition from other non-desired activities. This study illustrates the potential of phenotypic drug discovery to complement target-based approaches by providing new chemistry and biology leads. PMID: 29320511
- The study found that among patients with atopic dermatitis (AD), common FLG null mutations are associated with earlier AD onset in a dose-dependent manner, whereas TSLP rs1898671 appears unrelated to the timing of AD onset. PMID: 28479194
- Lactobacilli from the omnivorous group and all bifidobacteria significantly down-regulated IL-8. Notably, both genera also lowered the TSLP expression in stimulated Caco-2 cells, regardless of the diet regimen. PMID: 27863334
- This review focuses on recent advances on the effects of TSLP on obstetrical and gynecological diseases, including pregnancy failure, endometriosis, and cervical cancer. PMID: 27976427
- The increase in TSLP and TNF-alpha level observed in IS fluid was found to correlate with disease severity. The increased TSLP production from asthma sputum cells was abrogated by the addition of rIL-37. Regulation of the TSLP pathway may be a therapeutic approach for asthma. PMID: 27528425
- House dust mite sublingual immunotherapy downregulated Th2-type immune responses mediated by the TSLP-OX40L signaling pathway in patients with persistent moderate to severe allergic rhinitis. PMID: 27012942
- The results suggest that IL-1beta may be an early key mediator for the acquisition of an Atopic dermatitis (AD) phenotype through induction of thymic stromal lymphopoietin (TSLP) and alteration of the epidermal homeostasis. PMID: 28191908
- House dust mite exposure increases the expression of TSLP through the PI3K/Akt signaling pathway in human bronchial epithelial 16HBE cells. PMID: 28400057
- Posttranslational modifications control the functional activity of TSLP in humans, and overproduction of TSLP may be a key trigger for the amplification of type 2 inflammation in diseases. PMID: 27744031
- The study provides evidence for the hypothesis that TSLP could reflect the histological severity of lumbar disc degeneration (LDD), and TSLP-siRNA and TSLPR-siRNA could inhibit apoptosis of nucleus pulposus cells. The evident information obtained from the investigation could lead the way for new therapeutic approaches regarding LDD treatment. PMID: 28746197
- Periostin-mediated TSLP production by keratinocytes directly stimulates cutaneous T-cell lymphoma (CTCL) tumor cell growth in addition to inducing a Th2-dominant tumor environment in CTCL. PMID: 27634769
- This study shows that TSLP may be involved in the pathogenesis of asthma and rhinitis; dust mite and mugwort allergy could increase it significantly. PMID: 28303765
- Serum TSLP levels were significantly increased in systemic sclerosis patients compared to healthy donors, and were associated with a higher frequency of vasculopathy. The proportion of TSLP-positive dermal cells was increased in the skin of SSc patients compared with healthy donors, and was correlated with fibrosis. PMID: 27429171
- This study shows that NOD2 is an asthma-related factor that can promote cell proliferation and inflammatory response by mediating the expression of TSLP in human airway smooth muscle cells. PMID: 27889082
- The effects of TSLP on myeloid cells are crucial in reducing the multiple organ failure associated with systemic inflammation. PMID: 26934097
- Interactions between TSLP in follicular dendritic cells and IgA production in tonsils may be an important mechanism contributing to the pathogenesis of Immunoglobulin A (IgA) nephropathy. PMID: 27187742
- The study demonstrated that naturally occurring severe infections by the most common respiratory viruses in hospitalized infants induce nasal airway secretion of TSLP, IL-33, and periostin when compared with healthy controls. PMID: 28471975
- Variations in FLG and TSLP genotype were associated with differences in self-reported skin clearance, TCI usage, and steroid usage. PMID: 27902816
- A possible role of TSLP in immune homeostasis in HIV infection: higher plasma TSLP was found in individuals with primary HIV infection compared to both chronic HIV infection and healthy controls. PMID: 27769179
- The polymorphism was further reproducibly associated with a DNA methylation signature in whole blood (P = 4.5x10-40) that also associated with allergic sensitization and expression in blood of the cytokine TSLP (P = 1.1x10-4). Knockdown of the transcription factor predicted to bind the enhancer region (NHLH1) in a human cell line (HEK293) expressing NHLH1 resulted in lower TSLP expression. PMID: 27149122
- TSLP level was significantly higher in asthmatic than in nonasthmatic children. TSLP level was significantly different between allergic asthmatic and nonallergic nonasthmatic groups. PMID: 26999524
- While serum TSLP levels were unaffected by concomitant allergies and atopic comorbidities, serum levels of IL-31, IL-33, and sST2 were affected to a small extent. We found a positive correlation between TSLP, IL-31, and IL-33, and an inverse relationship between IL-33 and sST2. PMID: 27152943
- Results showed that TSLP promoted the production of alpha-SMA and collagen I (P<0.001), suggesting that it can accelerate MRC-5 cell fibrosis. PMID: 27385084
- TSLP is a key mediator in the pathogenesis of inflammatory bowel diseases, and further studies are needed to evaluate its role. [review] PMID: 27697608
- Letter: report decreased salivary gland TSLP expression in primary Sjogren's syndrome. PMID: 27494755
- A novel mouse xenograft model to study the role of TSLP-induced CRLF2 signals in normal and malignant human B lymphopoiesis has been developed. PMID: 26611474
- Heat stress-induced HSPs can significantly reduce the production and secretion of TSLP from keratinocytes cultured under a Th2 environment. PMID: 26419317
- TSLP expression in the skin is mediated via RARgamma-RXR pathways. PMID: 26531761
- Epidermal thymic stromal lymphopoietin predicts the development of atopic dermatitis during infancy. PMID: 26879860
- The study shows that specific food antigens can trigger innate immune-mediated esophageal TSLP secretion. PMID: 26992000
- Production by monocyte-derived dendritic cells requires the integration of signals from dectin-1, the IL-1 receptor, and endoplasmic reticulum stress response signaling pathways. PMID: 26573878
- The association of TSLP polymorphism rs2289278 with atopic dermatitis (AD) was stronger in children with allergic sensitization than in children without atopy, and TSLP polymorphisms also increased the risk of asthma in children with AD. PMID: 26712523
- The positive feedback loop between TSLP, IL-33, and their receptors, and Th2 cytokines may facilitate Th2-skewed inflammation in eosinophilic CRSwNP. PMID: 26095319
- Results show that rs1837253 polymorphism may be directly involved in the regulation of TSLP secretion. PMID: 25515628
- Upon TSLP stimulation, the cells with the highest TSLPR expression level showed enhanced proliferation and JAK/STAT-mediated gene regulation in a dose-dependent manner. PMID: 26652578
- Thymic stromal lymphopoietin activation of basophils in patients with allergic asthma is IL-3 dependent. PMID: 25962901
Q&A
What are the key functional assays to validate recombinant human TSLP activity in experimental systems?
Recombinant TSLP activity is typically validated using cell proliferation assays, phosphorylation studies, and dendritic cell (DC) maturation assays. For example:
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Proliferation assays: Transfect cells with TSLPR and IL-7Rα subunits (e.g., Ba/F3 cell lines) and measure growth in response to TSLP using MTT or BrdU incorporation .
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Phosphorylation studies: Monitor Stat3 and Stat5 activation via Western blotting in TSLPR/IL-7Rα-expressing cells, as TSLP binding induces receptor dimerization and downstream signaling .
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DC maturation assays: Treat monocytes or CD11c+ DCs with TSLP and assess upregulation of CD40, CD80, and CD86 via flow cytometry, alongside chemokine release (e.g., CCL22) using ELISA .
Data Table: Functional Assay Parameters
How can computational methods optimize antibody binding to TSLP for therapeutic applications?
Alanine scanning and molecular docking are critical for identifying residues critical for TSLP-receptor interactions. For example:
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Alanine scanning: Systematically replace amino acids in the TSLP-binding region of antibodies (e.g., T6 antibody) to identify residues essential for affinity .
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Docking tools: Use mCSM-PPI2 or GEO-PPI to predict binding energy changes and prioritize mutations (e.g., F→V substitutions to enhance hydrophobic interactions) .
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Fragment-based screening: Virtually screen small-molecule libraries (e.g., Maybridge or ZoBio fragments) to identify compounds that disrupt TSLP:TSLPR interactions, as validated via biochemical assays .
Data Table: Computational Optimization Workflow
Why does high TSLP expression in head and neck squamous cell carcinoma (HNSCC) not correlate with dendritic cell infiltration or prognosis?
TSLP’s ligand-receptor dissociation explains this paradox:
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Tumor-derived TSLP: Overexpressed in HNSCC epithelial cells but insufficiently activates DCs due to low receptor expression (TSLPR/IL-7Rα) in tumor-infiltrating DCs .
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Stromal microenvironment: Adjacent non-tumor epithelial cells may express TSLP in response to chronic inflammation (e.g., oral lichen planus), independent of tumor biology .
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Survival analysis: No association between TSLP levels and recurrence-free survival, suggesting TSLP’s role may be context-dependent (e.g., tumor differentiation vs. immune evasion) .
Key Contradiction: While TSLP promotes Th2 responses in allergy, its tumor-promoting vs. -protective effects remain unresolved, necessitating context-specific studies .
What receptor subunits are required for TSLP signaling, and how do they differ between species?
TSLP signals via a heterodimeric receptor complex:
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Human/mouse TSLPR: A novel hemopoietin receptor subunit paired with IL-7Rα .
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Receptor expression: Co-localized on monocytes, DCs, and basophils in humans; limited on T/B cells .
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Species differences: Mouse TSLP binds TSLPR alone, while human TSLP requires IL-7Rα for signaling, explaining divergent functional roles (e.g., B cell development) .
Data Table: Receptor Heterodimerization
| Species | Receptor Subunits | Critical Residues for Binding |
|---|---|---|
| Human | TSLPR + IL-7Rα | TSLPR: extracellular domain residues |
| Mouse | TSLPR alone | N/A (IL-7Rα not required) |
What computational strategies can inhibit the TSLP:TSLPR interaction for therapeutic targeting?
Fragment-based virtual screening and molecular dynamics (MD) simulations are effective:
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Fragment libraries: Screen Maybridge/ZoBio fragments for binding to TSLP’s receptor-binding site (e.g., hydrophobic pockets near H-bond donors) .
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Markov State Models (MSMs): Use unbiased MD to model binding pathways and identify transient intermediates, prioritizing fragments that stabilize unbound states .
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Biochemical validation: Test top fragments (e.g., pyrimidine derivatives) in a BLI-based TSLP:TSLPR binding assay or alkaline phosphatase fusion protein assay .
Case Study: Four fragments reduced binding by >25% at mM concentrations, highlighting the feasibility of small-molecule TSLP inhibitors .
How does TSLP influence B cell development and function, and what are the implications for autoimmune diseases?
TSLP’s role in B cells is context-dependent:
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Fetal B cell development: Promotes B220+/IgM+ B cell maturation in fetal liver, unlike IL-7 (which supports pre-B cells) .
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Autoimmunity: Elevated TSLP in systemic lupus erythematosus (SLE) drives B cell activation, autoantibody production, and autoimmune hemolytic anemia .
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Cancer: TSLPR mutations in B cell leukemia highlight TSLP’s oncogenic potential, requiring careful evaluation of therapeutic targeting .
Data Table: TSLP in B Cell Biology
What are the critical residues for TSLP binding to its receptor, and how can they be targeted?
Key residues include hydrophobic and polar interactions:
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TSLP: Tyr29, Gln159 (N-terminal domain) mediate receptor binding .
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TSLPR: Extracellular domain residues (e.g., Arg123, Glu167) stabilize TSLP via H-bonding and charge interactions .
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Targeting strategies:
Data Table: Critical Residues
| Residue (TSLP) | Role in Binding | Targeting Approach |
|---|---|---|
| Tyr29 | Hydrophobic core | Antibody N-terminal binding |
| Gln159 | H-bond with TSLPR | Small-molecule fragment screening |
How should researchers design experiments to study TSLP’s role in Th2 responses?
Experimental workflows:
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In vitro polarization: Treat CD4+ T cells with TSLP + DCs to induce IL-4/IL-13 production, measured via intracellular cytokine staining .
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In vivo models: Use TSLP transgenic mice or ovalbumin-induced asthma models to assess airway hyperresponsiveness and eosinophil infiltration .
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Mechanistic studies: Block TSLP (e.g., AMG157 antibody) to dissect its role in Th2 cytokine production vs. DC maturation .
Data Table: Th2 Response Assays
| Model | Readout | TSLP’s Role |
|---|---|---|
| In vitro (T cells) | IL-4/IL-13 (FACS) | Direct Th2 polarization |
| In vivo (asthma) | Eosinophils (BALF) | Indirect via DC-driven Th2 |
What challenges exist in studying TSLP’s role in cancer, and how can they be addressed?
Key challenges:
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Tumor vs. microenvironment origin: TSLP overexpression in HNSCC epithelial cells vs. stromal inflammation complicates interpretation .
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Receptor expression: Limited TSLPR/IL-7Rα on tumor-infiltrating DCs in HNSCC, reducing functional impact .
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Context-dependent effects: TSLP may promote Th2 immunity in allergy but suppress Th1/Th17 in cancer, requiring organ-specific models .
Solutions:
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Spatial transcriptomics: Map TSLP expression in tumor vs. stromal compartments.
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Receptor knockout models: Use TSLPR−/− mice to isolate TSLP’s direct vs. indirect effects.
What are the best methods to validate TSLP’s effect on dendritic cell maturation?
Validation strategies:
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Surface marker analysis: Treat CD11c+ DCs with TSLP and quantify CD40/CD80/CD86 via flow cytometry (gating on CD11c+CD14− cells) .
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T cell activation assays: Co-culture TSLP-treated DCs with allogenic T cells and measure IFN-γ/IL-4 production to assess Th2 skewing .
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Chemokine profiling: Use Luminex assays to detect CCL22, CCL17, and CXCL12, which recruit T cells and eosinophils .
