Coptisine Alleviates Imiquimod-Induced Psoriasis-like Skin Lesions and Anxiety-like Behavior in Mice

Abstract

Psoriasis is a common inflammatory skin disorder, which can be associated with psychological disorders, such as anxiety and depression. This study investigated the efficacy and the mechanism of action of a natural compound coptisine using imiquimod (IMQ)-induced psoriasis mice. Coptisine reduced the severity of psoriasis-like skin lesions, decreased epidermal hyperplasia and the levels of inflammatory cytokines TNF-α, IL-17, and IL-22. Furthermore, coptisine improved IMQ-induced anxiety in mice by increasing the number of entries and time in open arms in the elevated plus maze (EPM) test. Coptisine also lowered the levels of inflammatory cytokines TNF-α and IL-1β in the prefrontal cortex of psoriasis mice. HaCaT keratinocytes and BV2 microglial cells were used to investigate the effects of coptisine in vitro. In M5-treated HaCaT cells, coptisine decreased the production of IL-6, MIP-3α/CCL20, IP-10/CXCL10, and ICAM-1 and suppressed the NF-κB signaling pathway. In LPS-stimulated BV2 cells, coptisine reduced the secretion of TNF-α and IL-1β. These findings suggest that coptisine might be a potential candidate for psoriasis treatment by improving both disease severity and psychological comorbidities.

Keywords: anxiety; coptisine; imiquimod; inflammation; psoriasis.

Figure 1

Effects of coptisine on psoriasis-like skin symptoms in IMQ-treated mice. (A) Representative skin lesions from mice of five groups. PASI score (B) and spleen index (C) were measured. (D) Representative H&E staining results and quantification of epidermal thickness in skin lesions. Scale bar: 100 μm, magnification: 20×. (E) Levels of IL-17, IL-22, TNF-α, and IFN-γ in skin lysates. The data represent the means ± SDs (n = 5 per experiment). * p < 0.05, ** p < 0.01, *** p < 0.001 using one-way ANOVA with post hoc Tukey’s test. NC, normal control; IMQ, imiquimod; C, coptisine; CLO, clobetasol.

Figure 1

Effects of coptisine on psoriasis-like skin symptoms in IMQ-treated mice. (A) Representative skin lesions from mice of five groups. PASI score (B) and spleen index (C) were measured. (D) Representative H&E staining results and quantification of epidermal thickness in skin lesions. Scale bar: 100 μm, magnification: 20×. (E) Levels of IL-17, IL-22, TNF-α, and IFN-γ in skin lysates. The data represent the means ± SDs (n = 5 per experiment). * p < 0.05, ** p < 0.01, *** p < 0.001 using one-way ANOVA with post hoc Tukey’s test. NC, normal control; IMQ, imiquimod; C, coptisine; CLO, clobetasol.

Figure 2

Effects of coptisine on the behavioral changes in IMQ-treated mice. (A) Representative trajectory maps in the EPM test. (B) The number of entries, time, and distance in open arms in the EPM was recorded. (C) The immobility time in TST was recorded. The data represent the means ± SDs (n = 5 per experiment). * p < 0.05, ** p < 0.01, *** p < 0.001 using Student’s t-test for unpaired experiments. NC, normal control; IMQ, imiquimod; C, coptisine; CLO, clobetasol.

Figure 2

Effects of coptisine on the behavioral changes in IMQ-treated mice. (A) Representative trajectory maps in the EPM test. (B) The number of entries, time, and distance in open arms in the EPM was recorded. (C) The immobility time in TST was recorded. The data represent the means ± SDs (n = 5 per experiment). * p < 0.05, ** p < 0.01, *** p < 0.001 using Student’s t-test for unpaired experiments. NC, normal control; IMQ, imiquimod; C, coptisine; CLO, clobetasol.

Figure 3

Correlations between the number of entries and time in open arms in the EPM test and PASI score, skin levels of IL-17, IL-22, TNF-α were analyzed using Pearson’s correlation. EPM, elevated plus maze; PASI, psoriasis area severity index.

Figure 3

Correlations between the number of entries and time in open arms in the EPM test and PASI score, skin levels of IL-17, IL-22, TNF-α were analyzed using Pearson’s correlation. EPM, elevated plus maze; PASI, psoriasis area severity index.

Figure 4

Effects of coptisine on the serum CORT levels and neuroinflammation in IMQ-treated mice. (A) Serum levels of CORT. (B) Levels of TNF-α, IL-1β, and IL-6 in the PFC. The data represent the means ± SDs (n = 5 per experiment). * p < 0.05, ** p < 0.01, *** p < 0.001 using Student’s t-test for unpaired experiments. NC, normal control; IMQ, imiquimod; C, coptisine; CLO, clobetasol; CORT, corticosterone.

Figure 5

Effect of coptisine on the production of inflammatory cytokines and chemokines in M5-treated HaCaT cells. (A) The viability of HaCaT cells was measured using MTT assays. (B) The levels of IP-10/CXCL10, IL-6, ICAM-1, and MIP-3α/CCL20 in cell culture media were evaluated using ELISA kits. (C) Protein levels of NF-κB, lamin B2 in the nucleus, and protein levels of p-IKK, IκB-α, β-actin in the cytoplasm. The data represent the means ± SDs (n = 3 per experiment). * p < 0.05, ** p < 0.01, *** p < 0.001 using Student’s t-test for unpaired experiments.

Figure 5

Effect of coptisine on the production of inflammatory cytokines and chemokines in M5-treated HaCaT cells. (A) The viability of HaCaT cells was measured using MTT assays. (B) The levels of IP-10/CXCL10, IL-6, ICAM-1, and MIP-3α/CCL20 in cell culture media were evaluated using ELISA kits. (C) Protein levels of NF-κB, lamin B2 in the nucleus, and protein levels of p-IKK, IκB-α, β-actin in the cytoplasm. The data represent the means ± SDs (n = 3 per experiment). * p < 0.05, ** p < 0.01, *** p < 0.001 using Student’s t-test for unpaired experiments.

Figure 6

Effect of coptisine on the production of inflammatory cytokines in LPS-stimulated BV2 cells. (A) The viability of BV2 cells was measured using MTT assays. (B) The levels of TNF-α and IL-1β in cell culture media were evaluated using ELISA kits. The data represent the means ± SDs (n = 3 per experiment). * p < 0.05, ** p < 0.01, *** p < 0.001 using Student’s t-test for unpaired experiments.