166P - Three-dimensional (3D) Innervation of Mouse Lungs and Airways in a Lung Metastatic Tumor Model

Background

Schwann cells (SCs) are a type of peripheral nerve system(PNS) glial cell that support the viability of myelinated and unmyelinated peripheral nerve fibers. Our previous studies identified SCs in human lung cancer specimens and demonstrated that SCs could increase the metastasis of lung cancer by activating the PI3K/AKT/GSK-3b/Snail-7wist signaling pathway and enhancing M2 macrophage polarization via CCL2 secretion. However, in the lung cancer mouse model, complete identification of airway nerves (or other cellular/subcellular objects) has not been possible due to patchy distribution and micron-scale size.

Methods

In this study, we describe a method using tissue clearing to acquire the first complete image of three-dimensional (3D) innervation in lung cancer. Mouse airways were harvested from the Metastatic tumor model of C57BI/6 mice and separated from the heart. The tissues were dehydrated, rehydrated and completely transparented. The specimens were labeled for the pan-neuronal marker PGP9.5 with a mouse antibody. All images were acquired using a confocal microscope. 3D images of fluorescently casted airways were processed to make airway masks. To quantify visceral pleural nerve distribution in mice, nerves were modeled using computer tractography and measured in different lung cancer regions.

Results

We found that nerves are widely distributed in both lung and lung tissues. The shape of peripheral nerves is similar to blood vessels, showing reticular shape along the bronchi and bronchioles. However, the distribution of peripheral nerves in the lung has not changed due to lung cancer. Interestingly and critically, the fluorescence intensity of the nerve near the side of lung cancer is much stronger, suggesting that the phenotype of peripheral nerves may change after interaction with lung cancer cells. The nerve growth in lung cancer tissue is abundant and active.

Conclusions

We first complete the image of three-dimensional (3D) innervation in lung cancer. The interaction between peripheral nerves and lung cancer may affect the phenotype of peripheral nerves and thus regulate the malignant biological course of lung cancer. PNS may play an oncogenic role in lung tumor progression and may serve as a therapeutic target for further analysis.

Legal entity responsible for the study

Shanghai Chest Hospital.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.