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Updated: Dec 9, 2025
Characterization of a Novel Human Organotypic Retinal Culture Technique
Published on: June 9, 2021
NLRP3 Blockade Suppresses Pro-Inflammatory and Pro-Angiogenic Cytokine Secretion in Diabetic Retinopathy
Guangrui Chai1, Shu Liu2, Hongwei Yang1
1Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, People's Republic of China.
Background:
Inflammation and angiogenesis are the two dominant mechanisms of diabetic retinopathy (DR), which act more as mutual pathways rather than individual processes. However, the underlying mechanism of their interactions is still unclear. Here, we explored the potential crossing points between these pathways and the targeted therapeutic method in rats with DR.
Materials And Methods:
Sprague-Dawley rats were randomly assigned to four groups: normal control group, streptozocin (STZ)-induced diabetes mellitus (DM) group, DM+shNC (non-specific negative control shRNA) group, and DM+shNLRP3 group. Silencing the NLR family pyrin domain containing 3 (NLRP3) protein was performed by intravitreal injections of NLRP3-targeted shRNA (shNLRP3) for rats in the DM+shNLRP3 group. All the rats' retinas were collected for further morphological examination and pro-inflammatory and pro-angiogenic cytokine detection. Human retinal endothelial cells (HRECs) were also employed to explore the underlying mechanism.
Results:
NLRP3-targeted shRNA given by intravitreal injection effectively alleviated the retinal histopathological changes in STZ-induced diabetic rats, which reduced the activation of the NLRP3 inflammasome and suppressed the expressions of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and inflammatory cytokines in diabetic rats' retinas. In HRECs, NLRP3 over-expressing plasmid evoked an increase in pro-inflammatory cytokines and VEGF. In addition, YC-1, a HIF-1α inhibitor, could reverse the NLRP3 over-expression-induced VEGF production but not the pro-inflammatory cytokine expressions.
Conclusion:
Our results suggest NLRP3 inflammasome as the potential cross-point between inflammation and pro-angiogenesis in DR and support the effectiveness of NLRP3-targeted shRNA administrated by intravitreal injection in animal models of DR. The protective effect of NLRP3-targeted shRNA may stem from the inhibition of both pro-inflammatory cytokines and HIF-1α/VEGF axis.
Insights
This study identifies the NLRP3 inflammasome as a key link between inflammation and blood vessel growth in diabetic retinopathy (DR). Intravitreal injection of NLRP3-targeted shRNA effectively treated DR in rats by reducing inflammation and inhibiting key growth factors.
Area of Science:
- Ophthalmology
- Immunology
- Molecular Biology
Background:
- Diabetic retinopathy (DR) involves complex interactions between inflammation and angiogenesis.
- The precise molecular mechanisms linking these pathways in DR remain unclear.
Purpose of the Study:
- To investigate the role of the NLR family pyrin domain containing 3 (NLRP3) inflammasome as a potential intersection point between inflammation and angiogenesis in DR.
- To evaluate the therapeutic potential of targeting NLRP3 using shRNA in a rat model of DR.
Main Methods:
- Streptozotocin (STZ)-induced diabetes mellitus (DM) in Sprague-Dawley rats.
- Intravitreal injection of NLRP3-targeted shRNA (shNLRP3) or non-specific shRNA (shNC).
- Assessment of retinal histopathology, pro-inflammatory and pro-angiogenic cytokines, and NLRP3 inflammasome activation.
- In vitro studies using human retinal endothelial cells (HRECs) with NLRP3 overexpression and HIF-1α inhibition.
Main Results:
- Intravitreal shNLRP3 administration ameliorated DR-related retinal damage in rats.
- NLRP3 silencing reduced NLRP3 inflammasome activation, HIF-1α, VEGF, and inflammatory cytokine expression.
- NLRP3 overexpression in HRECs increased pro-inflammatory cytokines and VEGF; HIF-1α inhibition partially reversed VEGF increase.
Conclusions:
- The NLRP3 inflammasome acts as a crucial cross-point connecting inflammation and pro-angiogenesis in DR.
- Intravitreal administration of NLRP3-targeted shRNA demonstrates therapeutic efficacy in a DR animal model.
- The protective effects are attributed to the inhibition of pro-inflammatory cytokines and the HIF-1α/VEGF pathway.
