Inhibition of macrophage migration in zebrafish larvae demonstrates in vivo efficacy of human CCR2 inhibitors.

The chemokine signaling axes CCR2-CCL2 and CXCR3-CXCL11 participate in the inflammatory response by recruiting leukocytes to damaged tissue or sites of infection and are, therefore, potential pharmacological targets to treat inflammatory disorders. Although multiple CCR2 orthosteric and allosteric inhibitors have been developed, none of these compounds has been approved for clinical use, highlighting the need for a fast, simple and robust preclinical test system to determine the in vivo efficacy of CCR2 inhibitors. Herein we show that human CCL2 and CXCL11 drive macrophage recruitment in zebrafish larvae and that CCR2 inhibitors designed for humans also limit macrophage recruitment in this model organism due to the high conservation of the chemokine system. We demonstrated anti-inflammatory activities of three orthosteric and two allosteric CCR2 inhibitors using macrophage recruitment to injury as a functional read-out of their efficiency, while simultaneously evaluating toxicity. These results provide proof-of-principle for screening CCR2 inhibitors in the zebrafish model.

Bu-Shen-Fang-Chuan formula attenuates T-lymphocytes recruitment in the lung of rats with COPD through suppressing CXCL9/CXCL10/CXCL11-CXCR3 axis.

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease characterized by irreversible airflow limitation. The current medications show limited effects on the decline of pulmonary function in COPD. Our multicenter clinical trial found that Bu-Shen-Fang-Chuan fomula (BSFCF), a Chinese herbal formula, markedly reduced the frequencies of acute exacerbation of COPD and delayed lung function decline. However, the underlying mechanisms are still unclear. In this study, we established a COPD rat model through a 6-month exposure to cigarette smoke (CS) and found that BSFCF (7.2 g/kg) effectively improved CS-induced reduction in pulmonary function and remarkably decreased the numbers of inflammatory cells in bronchoalveolar lavage fluid (BALF). Importantly, BSFCF treatment notably prevented the accumulation of T-lymphocytes (especially CD8+ T-cells) in the lung of COPD rats. RNA sequencing analysis of lung tissue demonstrated that CXCL9/CXCL10/CXCL11-CXCR3 chemokine axis in the lung of CS-exposed rats was significantly suppressed by BSFCF. Moreover, our Real-time PCR data verified that BSFCF evidently inhibited the mRNA expressions of CXCL9, CXCL10, CXCL11 and CXCR3. Conclusively, BSFCF markedly improved pulmonary function and attenuated CD8+ T-cells recruitment in the lung of CS-exposed rats, which were partially through inhibition of CXCL9/CXCL10/CXCL11-CXCR3 axis.

Xia-Yu-Xue Decoction Inhibits Intestinal Epithelial Cell Apoptosis in CCl4-Induced Liver Fibrosis.

BACKGROUND/AIMS: Intestine-derived endotoxin is thought to play a role in the development of liver fibrosis. However, the pathological change in the intestine during liver fibrosis is still poorly understood. Here, we investigated the effects of Xia-yu-xue decoction (XYXD) on intestinal inflammation, apoptosis, and tight junction integrity in the carbon tetrachloride (CCl4)-induced liver fibrosis. METHODS: Murine liver fibrosis was developed by CCI4 treatment three times per week over a 6-week period. The CCl4-treated mice were divided into two groups: the CCl4-water group (n=8, CCl4) and the CCl4-XYXD group (n=8, CCl4+XYXD). The CCl4+XYXD mice were treated with XYXD from the beginning of the first week. The expression of inflammatory cytokines and apoptotic molecules were examined using immunohistochemistry, real-time PCR, and western blot. The intestinal epithelial cell apoptosis was examined by TUNEL staining. The tight junction-related molecules, such as ZO-1, claudin, and occludin in the gut were measured by real-time PCR. RESULTS: In CCl4-treated mice damage of the intestinal epithelia and infiltration of inflammatory cells into the lamina propria and muscular layer were observed. Proinflammatory markers MCP-1, TNF-α, CXCL11, IL-6, and CD68 were significantly increased in the intestinal epithelia in CCI4-treated mice. The expression of pro-apoptotic molecules including Fas and Bax was increased in the intestinal epithelia in CCI4-treated mice compared with that in control. The number of TUNEL-positive intestinal epithelial cells was also markedly increased in CCl4-treated mice. The expression of the tight junction proteins including ZO-1, claudin, and occludin was significantly decreased in CCI4-treated mice compared with that in control mice. Notably, XYXD treatment ameliorated increased inflammatory markers and apoptosis-related molecules and decreased tight-junction proteins in CCl4-treated mice. CONCLUSION: CCl4-treatment increased expression of proinflammatory cytokines and pro-apoptotic molecules and disrupted tight junction integrity in the intestine. XYXD treatment ameliorated intestinal inflammation, cell death, and tight junction disintegrity induced by CCl4 treatment, suggesting that XYXD inhibits CCl4-mediated liver fibrosis at least in part by ameliorating the intestinal epithelial damage.

Andrographolide inhibits prostate cancer by targeting cell cycle regulators, CXCR3 and CXCR7 chemokine receptors.

Despite state of the art cancer diagnostics and therapies offered in clinic, prostate cancer (PCa) remains the second leading cause of cancer-related deaths. Hence, more robust therapeutic/preventive regimes are required to combat this lethal disease. In the current study, we have tested the efficacy of Andrographolide (AG), a bioactive diterpenoid isolated from Andrographis paniculata, against PCa. This natural agent selectively affects PCa cell viability in a dose and time-dependent manner, without affecting primary prostate epithelial cells. Furthermore, AG showed differential effect on cell cycle phases in LNCaP, C4-2b and PC3 cells compared to retinoblastoma protein (RB(-/-)) and CDKN2A lacking DU-145 cells. G2/M transition was blocked in LNCaP, C4-2b and PC3 after AG treatment whereas DU-145 cells failed to transit G1/S phase. This difference was primarily due to differential activation of cell cycle regulators in these cell lines. Levels of cyclin A2 after AG treatment increased in all PCa cells line. Cyclin B1 levels increased in LNCaP and PC3, decreased in C4-2b and showed no difference in DU-145 cells after AG treatment. AG decreased cyclin E2 levels only in PC3 and DU-145 cells. It also altered Rb, H3, Wee1 and CDC2 phosphorylation in PCa cells. Intriguingly, AG reduced cell viability and the ability of PCa cells to migrate via modulating CXCL11 and CXCR3 and CXCR7 expression. The significant impact of AG on cellular and molecular processes involved in PCa progression suggests its potential use as a therapeutic and/or preventive agent for PCa.

Anti-cytomegalovirus effects of tricin are dependent on CXCL11.

It has been reported that treatment with tricin (4',5,7-trihydroxy-3',5'-dimethoxyflavone), a derivative of Sasa albo-marginata, after human cytomegalovirus (HCMV) infection significantly suppressed both infectious virus production and HCMV replication in the human embryonic fibroblast cell line MRC-5. In this paper, we examined the mechanisms for the anti-HCMV effects of tricin in MRC-5 cells. Exposure of fibroblasts to tricin inhibited infectious HCMV production, with concomitant decreases in levels of transcripts of the CXC chemokine IFN-inducible T cell alpha chemoattractant (I-TAC or CXCL11) gene. We also found that the transcripts of the HCMV immediate early (IE) gene and replication of HCMV were lower in CXCL11 gene-knockdown cells. These results suggest that tricin is a novel compound with potential anti-HCMV activity and that CXCL11 is one of the chemokines involved in HCMV replication. In addition, it is possible that CXCL11 is the one of the targets of tricin.

The yin and yang of chemokine receptor activation.

Chemokines represent a class of cytokines that control the migration of leucocytes. The human chemokine system comprises 44 ligands and 21 receptors that have evolved to control leucocyte migration. Although chemokines are an attractive therapeutic target for anti-inflammatory intervention, clinical trials of small molecule receptor antagonists have failed to demonstrate efficacy. One often cited explanation for this is the apparent redundancy within the chemokine system, wherein several ligands bind and activate each receptor. The work of Scholten et al. and Nedjai et al. reported in this issue of the British Journal of Pharmacology demonstrates that this redundancy does not exist at the molecular level and provides a powerful insight into the complex nature of chemokine receptor activation.

Inhibition of the CXCR3-mediated pathway suppresses ultraviolet B-induced pigmentation and erythema in skin.

BACKGROUND: Skin pigmentation by ultraviolet (UV) B radiation is caused in part by inflammation mediated by chemokines and cytokines secreted by keratinocytes in the irradiated area. However, such inflammatory processes have not been well documented. OBJECTIVES: To elucidate the inflammation processes caused by UVB irradiation using skin-lightening agents that suppress melanin synthesis after UVB irradiation. METHODS: Utilizing a three-dimensional (3D) skin model, agents that suppressed formation of sunburn cells (SBC) after UVB irradiation were screened. Molecules whose expression was upregulated by UVB irradiation and attenuated by pretreatment with the agent were then screened by gene microarray to explore the mechanism of UVB irradiation. Messenger RNA expression of the molecules identified to be responsible for melanin biosynthesis was knocked down with a Tet-off shRNA lentivirus construct to confirm the involvement of the molecule in the pigmentation pathway following UVB irradiation. RESULTS: Paeonia suffruticosa Andrews (PSA) pretreatment suppressed SBC formation in the 3D skin model, and erythema formation and pigmentation in volunteers exposed to UVB irradiation. Comprehensive gene analysis after UVB irradiation showed upregulation of CXCR3 and its ligands, CXCL9/monokine induced by interferon (IFN)-γ (MIG), CXCL10/10-kDa IFN-γ-induced protein (IP-10) and CXCL11/inducible T-cell α-chemoattractant (I-TAC). Upregulation of these genes was partially suppressed by PSA pretreatment. Melanin biosynthesis increased upon stimulation of CXCR3 ligands (MIG, IP-10 or I-TAC) and decreased following CXCR3 downregulation by shRNA knockdown. CONCLUSIONS: UVB irradiation activates CXCR3-mediated signalling that leads to melanin synthesis. PSA pretreatment shows a lightening effect partly by attenuating CXCR3-mediated signalling at the transcriptional level.