Fig 2: (A) Schedules for immunization and repeated challenges with Japanese cedar pollen (JCP) in the mice. Male ICR mice were sensitized by i.p. injections of JCP (0.1 mg in 50 µL PBS) with 2 mg Imuject Alum on days 0, 7, and 14. On days 21–24, animals were challenged intranasally (i.n.) with JCP (1 mg in 20 µL PBS, 10 µL/nostril) under the conscious state every 24 h. On day 25 (24 h after the last JCP challenge), the nasal responsiveness (sneezing/nasal rubbing) to intranasally administered histamine (Hist; 1–30 mM in saline, 10 µL/nostril) was measured under the conscious state. (B) Schedules for i.n. treatments with recombinant mouse periostin (Postn) in I mice. I male ICR mice were i.n. treated with Postn (10, 100, or 1000 ng/mL) or its vehicle PBS (5 µL/nostril, respectively) once daily for four consecutive days. Twenty-four hours after the last Postn treatment, the Hist responsiveness (sneezing/nasal rubbing) was measured as described above.

Fig 3: Effects of periostin (Postn) on nasal responsiveness to histamine in naive mice. Male ICR mice were challenged by intranasal (i.n.) administrations of recombinant mouse Postn (0–1000 ng/mL, 5 µL/nostril, respectively) every 24 h for 4 consecutive days under the conscious state (A). Twenty-four hours after the last Postn administration, sneezing (left panel) and nasal rubbing (right panel) induced by intranasally administered Hist (0–30 mM in saline, 10 µL/nostril) were counted for 10 min (B). Results are presented as mean ± SEM from 5 animals. * p < 0.05 and *** p < 0.001 vs. after vehicle by two-way ANOVA with Tukey multiple comparisons test.

Fig 4: Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of upregulated genes in periostin (Postn)-treated human nasal epithelial cells (hNECs) compared with control cells. Cultured hNECs were treated with recombinant human Postn (100 ng/mL) or its vehicle PBS for 24 h. Total RNA sample was subjected to RNA-seq analysis, and KEGG pathway enrichment analysis of the differentially expressed genes was performed. (A) KEGG enrichment analysis histogram ranked by −log10(adjusted p-value: padj). The numbers on the bars indicate the gene counts associated with each pathway. (B) KEGG enrichment analysis scatter plot. The x-axis represents the gene ratio, and the color indicates the adjusted p-value (padj). The size of each circle corresponds to the number of genes associated with each pathway. (C). Schematic representation of the oxidative phosphorylation pathway (KEGG ID: hsa00190) showing upregulated genes in Postn-treated hNECs. Red boxes indicate the genes that were significantly upregulated in Postn-treated cells.