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Updated: Mar 15, 2026
Rapid Evaluation of Toxicity of Chemical Compounds Using Zebrafish Embryos
Published on: August 25, 2019
Toxicity and anti-angiogenicity evaluation of Pak1 inhibitor IPA-3 using zebrafish embryo model
Sankar Jagadeeshan1, R Vivek Sagayaraj1, Navina Paneerselvan1
1Department of Genetics, Dr. ALM PGIBMS, University of Madras, Chennai, 600 113, India.
Abstract:
p21-activated kinase 1 (Pak1)-a key node protein kinase regulating various cellular process including angiogenesis-has been recognised to be a therapeutic target for multitude of diseases, and hence, various small molecule inhibitors targeting its activity have been tested. However, the direct toxic and anti-angiogenic effects of these pharmacologic agents have not been examined. In this study, we evaluate the translational efficacy of Pak1 inhibitor IPA-3 using zebrafish toxicity model system to stratify its anti-angiogenic potential and off-target effects to streamline the compound for further therapeutic usage. The morphometric analysis has shown explicit delay in hatching, tail bending, pericardial sac oedema and abnormal angiogenesis. We provide novel evidence that Pak1 inhibitor could act as anti-angiogenic agents by impeding the development of sub-intestinal vessel (SIV) and intersegmental vessels (ISVs) by suppressing the expression of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), neurophilin 1 (NRP1) and its downstream genes matrix metalloproteinase (MMP)-2 and MMP-9. Knockdown studies using 2-O-methylated oligoribonucleotides targeting Pak1 also revealed similar phenotypes with inhibition of angiogenesis accompanied with deregulation of major angiogenic factor and cardiac-specific genes. Taken together, our findings indicate that Pak1 signalling facilitates enhanced angiogenesis and also advocated the design and use of small molecule inhibitors of Pak1 as potent anti-angiogenic agents and suggest their utility in combinatorial therapeutic approaches targeting anomalous angiogenesis.
Insights
p21-activated kinase 1 (Pak1) inhibitors show promise as anti-angiogenic agents. This study used zebrafish to demonstrate Pak1 inhibition effectively blocks blood vessel formation, suggesting therapeutic potential for diseases involving abnormal angiogenesis.
Area of Science:
- Molecular Biology
- Developmental Biology
- Pharmacology
Background:
- p21-activated kinase 1 (Pak1) is a key regulator of cellular processes, including angiogenesis.
- Pak1 inhibitors are being developed as therapeutics, but their direct toxic and anti-angiogenic effects require thorough evaluation.
- Understanding Pak1's role is crucial for developing targeted therapies.
Purpose of the Study:
- To evaluate the translational efficacy and anti-angiogenic potential of the Pak1 inhibitor IPA-3.
- To assess the off-target effects of IPA-3 using a zebrafish toxicity model.
- To investigate the molecular mechanisms underlying Pak1 inhibition-induced anti-angiogenesis.
Main Methods:
- Utilized a zebrafish toxicity model system to assess the effects of IPA-3.
- Performed morphometric analysis to evaluate developmental and angiogenic phenotypes.
- Conducted knockdown studies using 2-O-methylated oligoribonucleotides targeting Pak1.
- Quantified the expression of key angiogenic factors like VEGF, VEGFR2, NRP1, MMP-2, and MMP-9.
Main Results:
- IPA-3 treatment resulted in delayed hatching, tail bending, pericardial edema, and abnormal angiogenesis in zebrafish.
- Pak1 inhibition impeded the development of sub-intestinal vessel (SIV) and intersegmental vessels (ISVs).
- Suppressed expression of VEGF, VEGFR2, NRP1, MMP-2, and MMP-9 was observed.
- Pak1 knockdown phenocopied IPA-3 effects, inhibiting angiogenesis and deregulating angiogenic and cardiac-specific genes.
Conclusions:
- Pak1 signaling plays a significant role in promoting angiogenesis.
- Pak1 inhibitors, like IPA-3, demonstrate potent anti-angiogenic properties.
- Small molecule inhibitors of Pak1 are viable candidates for therapeutic strategies targeting aberrant angiogenesis, potentially in combination therapies.
