Simple generation of hairless mice for in vivo imaging

The in vivo imaging of mice makes it possible to analyze disease progress non-invasively through reporter gene expression. As the removal of hair improves the accuracy of in vivo imaging, gene-modified mice with a reporter gene are often crossed with Hos:HR-1 mutant mice homozygous for the spontaneous Hrhr mutation that exhibit a hair loss phenotype. However, it is time consuming to produce mice carrying both the reporter gene and mutant Hrhr gene by mating. In addition, there is a risk that genetic background of the gene-modified mice would be altered by mating. To resolve these issues, we established a simple method to generate hairless mice maintaining the original genetic background by CRISPR technology. First, we constructed the pX330 vector, which targets exon 3 of Hr. This DNA vector (5 ng/µl) was microinjected into the pronuclei of C57BL/6J mice. Induced Hr gene mutations were found in many founders (76.1%) and these mutations were heritable. Next, we performed in vivo imaging using these gene-modified hairless mice. As expected, luminescent objects in their body were detected by in vivo imaging. This study clearly showed that hairless mice could be simply generated by the CRISPR/Cas9 system, and this method may be useful for in vivo imaging studies with various gene-modified mice

Clinical implications of the novel cytokine IL-38 expressed in lung adenocarcinoma: Possible association with PD-L1 expression.

Interleukin (IL)-38, a novel member of the IL-1 cytokine family, is homologous to IL-1 receptor antagonist (IL-1Ra) and IL-36Ra, and has been reported to act as an antagonist. IL-38 expression is found in tonsil, placenta, and spleen, and recent studies suggest an association between IL-38 and autoimmune diseases. However, whether IL-38 plays a role in carcinogenesis or cancer growth is unclear. In the present study, we identified increases in IL-38 expression by immunohistochemistry in multiple types of cancer cells. In the examination of 417 surgically resected primary lung adenocarcinomas, Fisher's exact tests showed significant associations between high IL-38 expression and high tumor grades, an advanced T status, advanced N status, advanced stage, and the presence of pleural and vessel invasions. Survival analyses by the Kaplan-Meier method showed that patients with high expression of IL-38 had significantly shorter disease-free survival and shorter overall survival after surgery than patients with low expression of IL-38 (log-rank test: P = 0.0021 and P = 0.0035, respectively). Moreover, programmed cell death-ligand 1 (PD-L1)-positive cases showed higher expression of IL-38 than PD-L1-negative cases (Wilcoxon rank-sum test: P < 0.0001). In conclusion, IL-38 was expressed in tumor cells of various cancers, and IL-38 expression was associated with poor survival of lung adenocarcinoma patients. IL-38 may affect host immunity or the tumor microenvironment, and contribute to the progression of lung adenocarcinoma

Clinicopathological characteristics of patients with primary lung adenocarcinoma.

<p>Clinicopathological characteristics of patients with primary lung adenocarcinoma.</p

Univariate and multivariate analyses of the relationship between IL-38 expression and other patient characteristics.

<p>Univariate and multivariate analyses of the relationship between IL-38 expression and other patient characteristics.</p

Univariate and multivariate analyses of DFS and OS in patients with primary lung adenocarcinoma.

<p>Univariate and multivariate analyses of DFS and OS in patients with primary lung adenocarcinoma.</p

Kaplan-Meier curves according to IL-38 expression in the analysis of PD-L1-negative cases and PD-L1-positive cases.

<p>Kaplan-Meier curves showing (A, C) disease-free and (B, D) overall survival of primary lung adenocarcinoma patients according to IL-38 expression in the analysis of (A, B) PD-L1-negative cases and (C, D) PD-L1-positive cases. IL-38: interleukin-38, PD-L1: programmed cell death-ligand 1.</p

Representative images of (left panel) HE staining, (middle panel) IL-38 staining, and (right panel) negative controls.

<p>(A) Human tonsil tissue. (B) Human placenta tissue. (C) Human spleen tissue. HE: Hematoxylin-eosin, IL-38: interleukin-38. Scale bar: 100 μm.</p