Chemokines and their receptors: roles in specific clinical conditions and measurement in the clinical laboratory

Cysteine-Cysteine Motif Chemokine Receptor 5 Expression in Letrozole-Induced Polycystic Ovary Syndrome Mice

Polycystic ovary syndrome (PCOS), which affects 5–10% of women of reproductive age, is associated with reproductive and metabolic disorders, such as chronic anovulation, infertility, insulin resistance, and type 2 diabetes. However, the mechanism of PCOS is still unknown. Therefore, this study used a letrozole-exposed mouse model in which mice were orally fed letrozole for 20 weeks to investigate the effects of letrozole on the severity of reproductive and metabolic consequences and the expression of cysteine–cysteine motif chemokine receptor 5 (CCR5) in letrozole-induced PCOS mice. The letrozole-treated mice showed a disrupted estrous cycle and were arrested in the diestrus phase. Letrozole treatment also increased plasma testosterone levels, decreased estradiol levels, and caused multicystic follicle formation. Furthermore, histological analysis of the perigonadal white adipose tissue (pgWAT) showed no significant difference in the size and number of adipocytes between the letrozole-treated mice and the control group. Further, the letrozole-treated mice demonstrated glucose intolerance and insulin resistance during oral glucose and insulin tolerance testing. Additionally, the expression of CCR5 and cysteine-cysteine motif ligand 5 (CCL5) were significantly higher in the pgWAT of the letrozole-treated mice compared with the control group. CCR5 and CCL5 were also significantly correlated with the homeostasis model assessment of insulin resistance (HOMA-IR). Finally, the mechanisms of insulin resistance in PCOS may be caused by an increase in serine phosphorylation and a decrease in Akt phosphorylation.

Human antigen R-regulated CCL20 contributes to osteolytic breast cancer bone metastasis

Breast cancer mainly spreads to bone, causing decreased survival of patient. Human antigen R (HuR) and chemokines are important molecules associated with mRNA stability and cell-cell interaction in cancer biology. Here, HuR knockdown inhibited bone metastasis and osteolysis of metastatic breast cancer cells in mice and HuR expression promoted the metastatic ability of cancer cells via CCL20 and GM-CSF. In contrast with the findings for GM-CSF, ELAVL1 and CCL20 expressions were markedly increased in breast tumor tissues and ELAVL1 expression showed a strong positive correlation with CCL20 expression in breast cancer subtypes, particularly the basal-like subtype. Metastasis-free survival and overall survival were decreased in the breast cancer patients with high CCL20 expression. We further confirmed the role of CCL20 in breast cancer bone metastasis. Intraperitoneal administration of anti-CCL20 antibodies inhibited osteolytic breast cancer bone metastasis in mice. Treatment with CCL20 noticeably promoted cell invasion and the secretion of MMP-2/9 in the basal-like triple-negative breast cancer cell lines, not the luminal. Moreover, CCL20 elevated the receptor activator of nuclear factors kappa-B ligand/osteoprotegerin ratio in breast cancer and osteoblastic cells and mediated the crosstalk between these cells. Collectively, HuR-regulated CCL20 may be an attractive therapeutic target for breast cancer bone metastasis.

Emerging role of chemokine CC motif ligand 4 related mechanisms in diabetes mellitus and cardiovascular disease: friends or foes?

Chemokines are critical components in pathology. The roles of chemokine CC motif ligand 4 (CCL4) and its receptor are associated with diabetes mellitus (DM) and atherosclerosis cardiovascular diseases. However, due to the complexity of these diseases, the specific effects of CCL4 remain unclear, although recent reports have suggested that multiple pathways are related to CCL4. In this review, we provide an overview of the role and potential mechanisms of CCL4 and one of its major receptors, fifth CC chemokine receptor (CCR5), in DM and cardiovascular diseases. CCL4-related mechanisms, including CCL4 and CCR5, might provide potential therapeutic targets in DM and/or atherosclerosis cardiovascular diseases.

Critical role of MKP-1 in lipopolysaccharide-induced osteoclast formation through CXCL1 and CXCL2

Osteoclast (OC) progenitors (OCP) have been defined in the bone marrow (BM) as CD3(-)CD45R(B220)(-)GR1(-)CD11b(lo/)(-)CD115(+) (dOCP) and more recently in the peripheral blood (PB) as Lym(-)Ly6G(-)CD11b(+)Ly6C(+). These progenitors respond to stimuli, including LPS from periopathogenic Aggregatibacter actinomycetemcomitans, activating MAPK signaling, resulting in cytokine/chemokine-mediated osteoclastogenesis. Intracellular negative signaling pathways, including MAPK phosphatase-1 (MKP-1, gene Dusp1) deactivate MAPK pathways (p-p38 and p-JNK) and reduce inflammatory cytokines/chemokines.

OBJECTIVE

To delineate the role of MKP-1 in chemokine-mediated OC formation using defined OC progenitor populations. Given its role in innate immune inflammatory signaling, we hypothesize that MKP-1 regulates LPS-induced OC formation from BM OCP through deregulated chemokines.

METHODS

BM and PB from WT and Dusp1(-/-) female mice (8-12weeks) was obtained and sorted into defined progenitor populations. BM sorted dOCP were primed with MCSF and RANKL (48h), blocked with vehicle or chemokine blocking antibodies and stimulated with LPS (48-96h). TRAP assay and OC activity were measured for OC formation and activity following treatments. NanoString Array and qPCR were utilized for gene expression analysis.

RESULTS

Dusp1(-/-) dOCPs formed more and larger osteoclasts from CD11b(hi) and dOCP compared to matched WT (P<0.05 each). PB-derived dOCP produced larger and more functional osteoclasts from Dusp1(-/-) mice compared to WT controls. NanoString array data revealed significant deregulation in chemokine expression from Dusp1(-/-) versus WT cells. qPCR validation of target genes revealed that Dusp1 deficient CD11b(+) populations display 1.5-3.5-fold greater expression of CXCL1 and 2-3-fold greater expression of CXCL2 compared to WT in CD11b(hi) and dOCP (P<0.05 each). Antibody blocking studies using anti-CXCL1 and CXCL2 antibodies blunted osteoclastogenesis in Dusp1(-/-) cells.

CONCLUSION

MKP-1 negatively regulates chemokine-driven OC formation and subsequent bone resorption in response to LPS stimulation. Collectively, these data provide useful insight into mechanisms potentially leading to the development of therapeutic treatment of periodontal disease.

T-lymphocytes expressing CC chemokine receptor-5 are increased in frail older adults

OBJECTIVES

To evaluate the frequencies of T-lymphocytes expressing CC chemokine receptor-5 (CCR5(+) T-cells) and their relationship with frailty in older adults.

DESIGN

Case-control study with an age-, race-, and sex-matched design.

SETTING

General Clinical Research Center.

PARTICIPANTS

Community-dwelling adults aged 72 and older from Baltimore, Maryland.

METHODS

Frailty was determined using five validated criteria: weakness, slow walking speed, fatigue, low physical activity, and weight loss. Those meeting three or more of these five criteria were defined as frail and those with none as nonfrail. Complete blood counts were performed to obtain peripheral lymphocyte counts using an automated (Coulter) counter. Peripheral blood was collected for surface immunofluorescent staining of CCR5 and other T-cell markers.

RESULTS

Twenty-six frail and matched nonfrail participants (mean age+/-standard deviation 83.8+/-5.3, range 72-94) completed the study. Frail participants had higher CCR5(+), CCR5(+)CD8(+), and CCR5(+)CD45RO(-) T-cell counts than matched nonfrail controls (349+/-160/mm(3) vs 194+/-168/mm(3), P=.02; 208+/-98/mm(3) vs 105+/-62/mm(3), P=.02; and 189+/-149/mm(3) vs 52+/-36/mm(3), P=.01; respectively). Furthermore, there was a trend toward graded increase in these T-cell counts across the frailty scores in frail participants (e.g., CCR5(+)CD8(+) counts of 123+/-52/mm(3), 248+/-115/mm(3), and 360+/-215/mm(3) for those with frailty scores of 3, 4, and 5, respectively).

CONCLUSION

These initial results suggest an expansion of the CCR5(+) T-cell subpopulation in frailty. They provide a basis for further characterization of CCR5(+) T-cells and their role in frailty, with potential therapeutic implications.

Role of chemokine receptor CXCR4/CXCL12 signaling pathway in hepatic metastasis of colorectal carcinoma

AIM: To investigate the potential role of chemokine receptor CXCR4/CXCL12 signal transduction pathway in hepatic metastasis of colorectal carcinoma.

METHODS: CXCR4 and CXCL12 expression were detected in tissue samples from 60 patients with colorectal carcinoma representing various clinicopathological parameters by Western blot analysis.

RESULTS: The levels of CXCR4 and CXCL12 proteins expression were increased significantly in colorectal cancer as compared with those in the adjacent normal mucosa (P < 0.05). In the 10 patients with lymph node metastasis, the expression of CXCR4 and CXCL12 were also markedly higher than those in those without metastasis (CXCR4: 3.9 ± 0.5 vs 2.2 ± 0.3, P < 0.05; CXCL12: 3.6 ± 0.5 vs 2.4 ± 0.3, P < 0.05). The over-expression of CXCR4 and CXCL12 proteins were correlated with TNM staging, and they were highly elevated in colorectal cancer at Ⅲ and Ⅳ stages as compared with those at Ⅰ and Ⅱ stages (CXCR4: 3.4 ± 0.6 vs 1.8 ± 0.3, P < 0.05; CXCL12: 3.6 ± 0.5 vs 1.8 ± 0.4, P < 0.05).

CONCLUSION: Over-expression of CXCR4/CXCL12 plays an important role in the hepatic metastasis of colorectal carcinoma.