Geniposide ameliorates atherosclerosis by regulating macrophage polarization via perivascular adipocyte-derived CXCL14.

ETHNOPHARMACOLOGICAL RELEVANCE: Gardenia jasminoides Ellis is a traditional Chinese medicine that has been used for treatment of various diseases, including atherosclerosis by clearing heat and detoxication. Geniposide is considered as the effective compounds responsible for the therapeutic efficacy of Gardenia jasminoides Ellis against atherosclerosis. AIM OF THE STUDY: To investigate the effect of geniposide on atherosclerosis burden and plaque macrophage polarization, with focus on its potential impact on CXCL14 expression by perivascular adipose tissue (PVAT). MATERIALS AND METHODS: ApoE-/- mice fed a western diet (WD) were used to model atherosclerosis. In vitro cultures of mouse 3T3-L1 preadipocytes and RAW264.7 macrophages were used for molecular assays. RESULTS: The results revealed that geniposide treatment reduced atherosclerotic lesions in ApoE-/- mice, and this effect was correlated with increased M2 and decreased M1 polarization of plaque macrophages. Of note, geniposide increased the expression of CXCL14 in PVAT, and both the anti-atherosclerotic effect of geniposide, as well as its regulatory influence on macrophage polarization, were abrogated upon in vivo CXCL14 knockdown. In line with these findings, exposure to conditioned medium from geniposide-treated 3T3-L1 adipocytes (or to recombinant CXCL14 protein) enhanced M2 polarization in interleukin-4 (IL-4) treated RAW264.7 macrophages, and this effect was negated after CXCL14 silencing in 3T3-L1 cells. CONCLUSION: In summary, our findings suggest that geniposide protects ApoE-/- mice against WD-induced atherosclerosis by inducing M2 polarization of plaque macrophages via enhanced expression of CXCL14 in PVAT. These data provide novel insights into PVAT paracrine function in atherosclerosis and reaffirm geniposide as a therapeutic drug candidate for atherosclerosis treatment.

Characterization of the bone marrow niche in patients with chronic myeloid leukemia identifies CXCL14 as a new therapeutic option.

Although tyrosine kinase inhibitors (TKIs) are effective in treating chronic myeloid leukemia (CML), they often fail to eradicate the leukemia-initiating stem cells (LSCs), causing disease persistence and relapse. Evidence indicates that LSC persistence may be because of bone marrow (BM) niche protection; however, little is known about the underlying mechanisms. Herein, we molecularly and functionally characterize BM niches in patients with CML at diagnosis and reveal the altered niche composition and function in these patients. Long-term culture initiating cell assay showed that the mesenchymal stem cells from patients with CML displayed an enhanced supporting capacity for normal and CML BM CD34+CD38- cells. Molecularly, RNA sequencing detected dysregulated cytokine and growth factor expression in the BM cellular niches of patients with CML. Among them, CXCL14 was lost in the BM cellular niches in contrast to its expression in healthy BM. Restoring CXCL14 significantly inhibited CML LSC maintenance and enhanced their response to imatinib in vitro, and CML engraftment in vivo in NSG-SGM3 mice. Importantly, CXCL14 treatment dramatically inhibited CML engraftment in patient-derived xenografted NSG-SGM3 mice, even to a greater degree than imatinib, and this inhibition persisted in patients with suboptimal TKI response. Mechanistically, CXCL14 upregulated inflammatory cytokine signaling but downregulated mTOR signaling and oxidative phosphorylation in CML LSCs. Together, we have discovered a suppressive role of CXCL14 in CML LSC growth. CXCL14 might offer a treatment option targeting CML LSCs.

CXC chemokines influence immune surveillance in immunological disorders: Polycystic ovary syndrome and endometriosis.

Reproductive health is a worldwide challenge, but it is of particular significance to women during their reproductive age. Several female reproductive problems, including polycystic ovary syndrome (PCOS) and endometriosis, affect about 10 % of women and have a negative impact on their health, fertility, and quality of life. Small, chemotactic, and secreted cytokines are CXC chemokines. Both PCOS and endometriosis demonstrate dysregulation of CXC chemokines, which are critical to the development and progression of both diseases. Recent research has shown that both in humans and animals, CXC chemokines tend to cause inflammation. It has also been found that CXC chemokines are necessary for promoting angiogenesis and inflammatory responses. CXC chemokine overexpression is frequently associated with poor survival and prognosis. CXC chemokine levels in PCOS and endometriosis patients impact their circumstances significantly. Hence, CXC chemokines have significant potential as diagnostic and prognostic biomarkers and therapeutic targets. The molecular mechanisms through which CXC chemokines promote inflammation and the development of PCOS and endometriosis are currently unknown. This article will discuss the functions of CXC chemokines in the promotion, development, and therapy of PCOS and endometriosis, as well as future research directions. The current state and future prospects of CXC chemokine -based therapeutic strategies in the management of PCOS and endometriosis are also highlighted.

IRX1 ameliorates sepsis-induced acute kidney injury in mice by promoting CXCL14.

BACKGROUND: Sepsis-induced acute kidney injury is a general critical complication having high relevance to kidney inflammation. In spite of advances in clinical and critical care, the specific and effective therapies for acute kidney injury are still insufficient. The present study aimed to investigate the protective effect of Iroquois homeobox genes (IRX) on sepsis-induced kidney dysfunction in mice. METHODS: In order to gain insight into sepsis-related actions in acute kidney injury, the cecal puncture-induced kidney injury animal model was established. The hematoxylin and eosin staining was used to measure the pathology of kidney tissues. The kidney function-related biomarkers, including neutrophil gelatinase-associated lipocalin, creatinine, kidney injury molecule-1, blood urea nitrogen, and inflammatory cytokines, which included tumor necrosis factor α, interleukin 1ß (IL-1ß), IL-6, and monocyte chemotactic protein 1, were detected by automated biochemical analyzer or their corresponding test kits. The protein expression was measured using Western blot analysis, and the apoptotic rate of kidney tissue was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. RESULTS: The present study revealed the protective ability of IRX1 in sepsis-induced acute kidney injury. This study also determined the potential mechanism of IRX1 on sepsis-induced inflammatory response and cell apoptosis. Finally, it highlighted that IRX1 exerted a protective influence on CLP-induced acute kidney injury by suppressing the activation of chemokine (C-X-C motif) ligand 14 (CXCL14). CONCLUSION: To conclude, the results suggest that overexpression of IRX1 could promote survival rate and suppress the CLP-induced apoptosis, inflammatory response, and kidney dysfunction through the activation of CXCL14. IRX1 and CXCL14 are essential to elucidate the mechanism of acute kidney injury. These findings may help to identify the promising targets for clinical sepsis therapy.

IRX1 ameliorates sepsis-induced acute kidney injury in mice by promoting CXCL14

Background Sepsis-induced acute kidney injury is a general critical complication having high relevance to kidney inflammation. In spite of advances in clinical and critical care, the specific and effective therapies for acute kidney injury are still insufficient. The present study aimed to investigate the protective effect of Iroquois homeobox genes (IRX) on sepsis-induced kidney dysfunction in mice. Methods In order to gain insight into sepsis-related actions in acute kidney injury, the cecal puncture-induced kidney injury animal model was established. The hematoxylin and eosin staining was used to measure the pathology of kidney tissues. The kidney function-related biomarkers, including neutrophil gelatinase-associated lipocalin, creatinine, kidney injury molecule-1, blood urea nitrogen, and inflammatory cytokines, which included tumor necrosis factor α, interleukin 1β (IL-1β), IL-6, and monocyte chemotactic protein 1, were detected by automated biochemical analyzer or their corresponding test kits. The protein expression was measured using Western blot analysis, and the apoptotic rate of kidney tissue was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Results The present study revealed the protective ability of IRX1 in sepsis-induced acute kidney injury. This study also determined the potential mechanism of IRX1 on sepsis-induced inflammatory response and cell apoptosis. Finally, it highlighted that IRX1 exerted a protective influence on CLP-induced acute kidney injury by suppressing the activation of chemokine (C-X-C motif) ligand 14 (CXCL14). Conclusion To conclude, the results suggest that overexpression of IRX1 could promote survival rate and suppress the CLP-induced apoptosis, inflammatory response, and kidney dysfunction through the activation of CXCL14. IRX1 and CXCL14 are essential to elucidate the mechanism of acute kidney injury. These findings may help to identify the promising targets for clinical sepsis therapy (AU)

Reduced Incidence of Necrotizing Enterocolitis due to the Anti-Inflammatory Effects of CXCL14 in Intestinal Tissue.

Bioinformatic analysis indicated that downregulated CXCL14 will occur in the intestinal tissue of patients with necrotizing enterocolitis (NEC). To reveal the relationship between CXCL14 and mucosal immune regulation, we designed and implemented the experiments to explore the potential function of CXCL14 in the pathogenesis of NEC. Firstly, this study confirmed that the expression of CXCL14 decreased in the intestinal tract of NEC children. Secondly, the experiments results showed that CXCL14 could ameliorate the inflammatory injury of intestinal tissue through the suppressive effect on the expression of TNF-α and INF-γ in vivo. Finally, we explained that activation of the TLR4 can reduce the expression level of CXCL14 in the intestinal tissue of mouse pups. Collectively, our study suggested that CXCL14 may negatively regulate the inflammatory response in intestinal tissue and play an essential role in NEC development and progression.

CXC chemokine­7 inhibits growth and migration of oral tongue squamous cell carcinoma cells, mediated by the epithelial­mesenchymal transition signaling pathway.

Oral tongue squamous cell carcinoma (OTSCC) is the most common oral malignancy with different histopathological symptoms and etiology of tumorigenesis. Migration and invasion is the most important characteristics of OTSCC, and limits tumor therapy in clinics. The epithelial­to­mesenchymal transition (EMT) signaling pathway is an important process in the progress of tumor cell migration and invasion. Previous studies have indicated that C­X­C chemokine receptor­7 (CXCR­7) promotes the progression and metastasis of tumor cells, presenting a potential target molecule for cancer therapy. The present study investigated the inhibitory effects of C­X­C chemokine­7 (CXC­7) on human OTSCC cells both in vitro and in vivo. The results demonstrated that the Tca8113 human OTSCC cell line expressed higher levels of CXC­7 mRNA compared with the hNOE human normal oral epithelial cell line. MTT assays indicated that CXC­7 suppressed Tca8113 cell growth, and the cytotoxicity of CXC­7 was indicated as the cell survival of the negative control group was significantly decreased compared with the blank control and hNOE cells. Migration and invasion assays revealed that CXC­7 inhibited Tca8113 cell local expansion and distant metastasis. In addition, the results demonstrated that the extracellular signal­regulated kinase (ERK)/protein kinase B (AKT) signaling pathway was inhibited after CXC­7 treatment in Tca8113 cells. N­cadherin, E­Cadherin, Snail and Slug expression levels in the ERK/AKT signaling pathway were inhibited in Tca8113 cells after treatment with CXC­7. It was demonstrated that important extracellular matrix proteins involved in cell migration, including Slug, collagen type I and Vimentin, were significantly downregulated by CXC­7 treatment. In conclusion, CXC­7 inhibited growth and migration in OTSCC cells, mediated by the EMT signaling pathway. This suggests that CXC­7 serves an inhibitory role in OTSCC migration, implicating CXCR­7 as a promising biomarker for chemokine receptor­based drug development.

Collagen IV and CXC chemokine-derived antiangiogenic peptides suppress glioma xenograft growth.

Peptides are receiving increasing attention as therapeutic agents due to their high binding specificity and versatility to be modified as targeting or carrier molecules. Particularly, peptides with antiangiogenic activity are of high interest because of their applicability to a wide range of cancers. In this study, we investigate the biological activity of two novel antiangiogenic peptides in preclinical glioma models. One peptide SP2000 is derived from collagen IV and the other peptide SP3019 belongs to the CXC family. We have previously characterized the capacity of SP2000 and SP3019 to inhibit multiple biological endpoints linked to angiogenesis in human endothelial cells in several assays. Here, we report additional studies using endothelial cells and focus on the activity of these peptides against human glioma cell growth, migration and adhesion in vitro, and growth as tumor xenografts in vivo. We found that SP2000 completely inhibits migration of the glioma cells at 50 µmol/l and SP3019 produced 50% inhibition at 100 µmol/l. Their relative antiadhesion activities were similar, with SP2000 and SP3019 generating 50% adhesion inhibition at 4.9 ± 0.82 and 21.3 ± 5.92 µmol/l, respectively. In-vivo glioma growth inhibition was 63% for SP2000 and 76% for SP3019 after 2 weeks of administration at daily doses of 10 and 20 mg/kg, respectively. The direct activity of these peptides against glioma cells in conjunction with their antiangiogenic activities warrants their further development as either stand-alone agents or in combination with standard cytotoxic or emerging targeted therapies in malignant brain tumors.

Antimicrobial effects of interferon-inducible CXC chemokines against Bacillus anthracis spores and bacilli.

Based on previous studies showing that host chemokines exert antimicrobial activities against bacteria, we sought to determine whether the interferon-inducible Glu-Leu-Arg-negative CXC chemokines CXCL9, CXCL10, and CXCL11 exhibit antimicrobial activities against Bacillus anthracis. In vitro analysis demonstrated that all three CXC chemokines exerted direct antimicrobial effects against B. anthracis spores and bacilli including marked reductions in spore and bacillus viability as determined using a fluorometric assay of bacterial viability and CFU determinations. Electron microscopy studies revealed that CXCL10-treated spores failed to undergo germination as judged by an absence of cytological changes in spore structure that occur during the process of germination. Immunogold labeling of CXCL10-treated spores demonstrated that the chemokine was located internal to the exosporium in association primarily with the spore coat and its interface with the cortex. To begin examining the potential biological relevance of chemokine-mediated antimicrobial activity, we used a murine model of inhalational anthrax. Upon spore challenge, the lungs of C57BL/6 mice (resistant to inhalational B. anthracis infection) had significantly higher levels of CXCL9, CXCL10, and CXCL11 than did the lungs of A/J mice (highly susceptible to infection). Increased CXC chemokine levels were associated with significantly reduced levels of spore germination within the lungs as determined by in vivo imaging. Taken together, our data demonstrate a novel antimicrobial role for host chemokines against B. anthracis that provides unique insight into host defense against inhalational anthrax; these data also support the notion for an innovative approach in treating B. anthracis infection as well as infections caused by other spore-forming organisms.

Peripheral blood stem cell mobilization: new regimens, new cells, where do we stand.

PURPOSE OF REVIEW: Granulocyte colony-stimulating factor-mobilized peripheral blood stem cells are widely used to reconstitute hematopoiesis; however, preclinical and clinical studies show that improvements to this mobilization can be achieved. We discuss the development of new mobilizing regimens and evaluation of new findings on mobilized stem cell populations that may improve the utility and convenience of peripheral blood stem cell transplant. RECENT FINDINGS: Chemokines and their receptors regulate leukocyte trafficking, and altering chemokine signaling pathways mobilizes stem cells. In recent trials, combination use of the chemokine (C-X-C motif) receptor 4 antagonist AMD3100 and granulocyte colony-stimulating factor mobilized more CD34 cells in fewer days than granulocyte colony-stimulating factor alone and allowed more patients to proceed to autotransplant. In preclinical studies the chemokine GRObeta synergizes with granulocyte colony-stimulating factor and when used alone or with granulocyte colony-stimulating factor mobilizes more primitive hematopoietic stem cells with less apoptosis, higher integrin activation, lower CD26 expression and enhanced marrow homing compared with granulocyte colony-stimulating factor. Hematopoietic stem cells mobilized by GRObeta or AMD3100 demonstrate superior engraftment and contribution to chimerism in primary and secondary transplant studies in mice, and peripheral blood stem cells mobilized by AMD3100 and granulocyte colony-stimulating factor in patients demonstrate enhanced engraftment capabilities in immunodeficient mice. SUMMARY: Alternate regimens differentially mobilize stem cell populations with unique intrinsic properties with the potential to expand the utility of hematopoietic transplantation. Continued mechanistic evaluation will be critical to our understanding of mechanisms of mobilization and their use in regenerative medicine.

Immune-mediated modulation of breast cancer growth and metastasis by the chemokine Mig (CXCL9) in a murine model.

Current immunotherapies are limited by several factors, including the failure to recruit sufficient numbers of immune effector cells to tumors. The chemokine monokine induced by gamma-interferon (Mig; CXCL9) attracts activated T cells and natural killer (NK) cells bearing the chemokine receptor CXCR3. We investigated Mig as an immunotherapeutic agent in a syngeneic murine model of metastatic breast cancer. We transfected the highly malignant murine mammary tumor cell line 66.1 to stably express murine Mig cDNA. Immune-competent mice injected with Mig-expressing tumor cells developed smaller local tumors and fewer lung metastases, and they survived longer than mice injected with vector-control tumor cells. Mig-mediated inhibition of local tumor growth was lost in the absence of host T cells. Mig-transduced tumors had increased numbers of CD4 T cells compared with vector-control tumors, consistent with the T-cell chemoattractant property of Mig, and many tumor-infiltrating host cells expressed CXCR3. NK cells had not been examined previously as a possible effector cell in Mig-based therapies. Our studies now show that NK cells are critical to the mechanism by which Mig limits metastasis. Inhibition of angiogenesis was not implicated as a mechanism of Mig-mediated therapy in this model. These studies support the hypothesis that by manipulating the Mig-CXCR3 gradient, it is possible to direct host immune effector cells to tumors, curtailing both local tumor growth and metastasis. These studies also implicate host NK cells as an additional effector cell critical for Mig-mediated control of metastasis.

Anti-angiogenic effects of interleukin-12 delivered by a novel hyperthermia induced gene construct.

PURPOSE: Interleukin-12 (IL-12) is a pro-inflammatory cytokine possessing anti-cancer and anti-angiogenic properties. This study quantitatively assessed the anti-angiogenic effect of IL-12 delivered using an adenoviral vector with murine IL-12 placed under control of a heat shock promoter. This approach limits systemic toxicity by restricting IL-12 delivery locally to the tumour. The kinetics of the downstream cytokines interferon-gamma (IFN-gamma) and interferon inducible protein-10 (IP-10) and other molecules affecting angiogenesis, vascular endothelial growth factor (VEGF) and plasminogen activator inhibitor-1 (PAI-1) were also studied. MATERIALS AND METHODS: 4T1 tumours were grown in Balb/C mice and the AdhspmIL-12 construct was injected intra-tumourally. The tumours were heated after 24 h using a water bath. At various time points post-heating the tumours were collected and quantitatively assessed for cytokine production and vascularity. RESULTS: A significant reduction was seen in the tumour vasculature of the treated group vs. the control group mice. Systemic effects of IL-12 were limited to generalized immunostimulation. No hepatoxicity was noted. CONCLUSIONS: This study suggests that IL-12 can be effectively delivered using a gene-based approach with a heat shock promoter. This results in quantitatively measurable anti-angiogenesis and general immunostimulation. The complex inter-play of other pro- and anti-angiogenic factors (IFN-gamma, IP-10, VEGF and PAI-1) was also studied.

BRAK/CXCL14 expression suppresses tumor growth in vivo in human oral carcinoma cells.

In order to find a suppressor(s) of tumor progression in vivo for oral carcinoma (OC), we searched for molecules down-regulated in OC cells when the cells were treated with epidermal growth factor (EGF), whose receptor is frequently over-activated in OC. The expression of BRAK, which is also known as CXC chemokine ligand14 (CXCL14), was down-regulated significantly by the treatment of OC cells with EGF as observed by cDNA microarray analysis followed by reverse-transcriptase polymerase chain reaction analysis. The EGF effect was attenuated by the co-presence of a MEK inhibitor. The rate of tumor formation in vivo of BRAK-expressing vector-transfected tumor cells in athymic nude mice was significantly lower than that of mock vector-transfected ones. In addition tumors formed in vivo by the BRAK-expressing cells were significantly smaller than those of the mock-transfected ones. These results indicate that BRAK/CXCL14 is a chemokine, having suppressive activity toward tumor progression of OC in vivo.

Neovasculogenic therapy to augment perfusion and preserve viability in ischemic cardiomyopathy.

BACKGROUND: Ischemic cardiomyopathy is a global health concern with limited therapy. We recently described endogenous revascularization utilizing granulocyte-macrophage colony stimulating factor (GMCSF) to induce endothelial progenitor cell (EPC) production and intramyocardial stromal cell-derived factor-1alpha (SDF) as a specific EPC chemokine. The EPC-mediated neovascularization and enhancement of myocardial function was observed. In this study we examined the regional biologic mechanisms underlying this therapy. METHODS: Lewis rats underwent left anterior descending coronary artery (LAD) ligation and developed ischemic cardiomyopathy over 6 weeks. Three weeks after ligation, the animals received either subcutaneous GMCSF and intramyocardial SDF injections or saline injections as control. Six weeks after LAD ligation circulating EPC density was studied by flow cytometry. Quadruple immunofluorescent vessel staining for mature, proliferating vasculature was performed. Confocal angiography was utilized to identify fluorescein lectin-lined vessels to assess perfusion. Ischemia reversal was studied by measuring myocardial adenosine triphosphate (ATP) levels. Myocardial viability was assayed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling detection of apoptosis and quantitation of myofilament density. RESULTS: The GMCSF/SDF therapy enhanced circulating leukocyte (13.1 +/- 4.5 x 10(6) vs 3.1 +/- 0.5 x 10(6)/cc, p = 0.001, n = 6) and EPC (14.2 +/- 6.6 vs 2.2 +/- 2.1/cc, p = 0.001, n = 6) concentrations. Tetraimmunofluorescent labeling demonstrated enhanced stable vasculature with this therapy (39.2 +/- 8.1 vs 25.4 +/- 5.1%, p = 0.006, n = 7). Enhanced perfusion was shown by confocal microangiography of borderzone lectin-labeled vessels (28.2 +/- 5.4 vs 11.5 +/- 3.0 vessels/high power field [hpf], p = 0.00001, n = 10). Ischemia reversal was demonstrated by enhanced cellular ATP levels in the GMCSF/SDF borderzone myocardium (102.5 +/- 31.0 vs 26.9 +/- 4.1 nmol/g, p = 0.008, n = 5). Borderzone cardiomyocyte viability was noted by decreased apoptosis (3.2 +/- 1.4% vs 5.4 +/- 1.0%, p = 0.004, n = 10) and enhanced cardiomyocyte density (40.0 +/- 5.6 vs 27.0 +/- 6 myofilaments/hpf, p = 0.01, n=10). CONCLUSIONS: Endogenous revascularization for ischemic cardiomyopathy utilizing GMCSF EPC upregulation and SDF EPC chemokinesis upregulates circulating EPCs, enhances vascular stability, and augments myocardial function by enhancing perfusion, reversing cellular ischemia, and increasing cardiomyocyte viability.

CXCR3/CXCR3 ligand biological axis impairs RENCA tumor growth by a mechanism of immunoangiostasis.

Metastatic renal cell carcinoma (RCC) responds poorly to chemo- or radiation therapy but appears to respond to systemic immunotherapy (i.e., IL-2 and/or IFN-alpha), albeit with only 5-10% durable response. The CXCR3/CXCR3 ligand biological axis plays an important role in mediating type 1 cytokine-dependent cell-mediated immunity, which could be beneficial for attenuating RCC if optimized. We found that systemic IL-2 induced the expression of CXCR3 on circulating mononuclear cells but impaired the CXCR3 ligand chemotactic gradient from plasma to tumor by increasing circulating CXCR3 ligand levels in a murine model of RCC. Moreover, the antitumor effect of systemic IL-2 was CXCR3-dependent, as IL-2 failed to inhibit tumor growth and angiogenesis in CXCR3-/- mice. We hypothesized that the immunotherapeutic effect of the CXCR3/CXCR3 ligand biological axis could be optimized by first priming with systemic IL-2 to induce CXCR3 expression on circulating mononuclear cells followed by enhancing the intratumor CXCR3 ligand levels to establish optimal CXCR3-dependent chemotactic gradient. We found that combined systemic IL-2 with an intratumor CXCR3 ligand (CXCL9) lead to significantly greater reduction in tumor growth and angiogenesis, increased tumor necrosis, and increased intratumor infiltration of CXCR3+ mononuclear cells, as compared with either IL-2 or CXCL9 alone. The enhanced antitumor effect of the combined strategy was associated with a more optimized CXCR3-dependent chemotactic gradient and increased tumor-specific immune response. These data suggest that the combined strategy of systemic IL-2 with intratumor CXCR3 ligand is more efficacious than either strategy alone for reducing tumor-associated angiogenesis and augmenting tumor-associated immunity, the concept of immunoangiostasis.

Efficacy of systemic administration of SDF-1 in a model of vascular insufficiency: support for an endothelium-dependent mechanism.

OBJECTIVE: Studies have reported that administration of stromal cell-derived factor-1 (SDF-1), the ligand for the G-protein coupled receptor CXCR4, increased collateral blood flow in a mouse model of vascular insufficiency via recruitment of endothelial precursor cells (EPC). The present study investigated the contribution of mature endothelial cells in the actions of SDF-1. METHODS: The regulation of SDF-1 and CXCR4 was examined in the rat cornea cauterization (CC) and aortic ring (AR) model. The functional significance of the SDF-1/CXCR4 pathway was explored in cultured endothelial cells, the AR model, and on collateral blood flow in a rat model of vascular insufficiency. RESULTS: In the present study, the CXCR4 transcript was dramatically upregulated in the rat CC and AR explants, systems containing and lacking bone marrow-derived EPCs, respectively. Addition of AMD3100, a selective CXCR4 antagonist, had no effect on vessel growth in the AR alone, but completely inhibited SDF-1 mediated increases in vascular sprouting. In cultured endothelial cells, SDF-1 alone or in combination with vascular endothelial growth factor (VEGF) significantly enhanced cell survival and migration. Finally, systemic administration of SDF-1 in a rat model of arterial insufficiency enhanced collateral blood flow above vehicle control and equal to that of VEGF after 2 weeks of treatment. CONCLUSION: These studies support activation of the SDF-1/CXCR4 axis as a means to promote blood vessel growth and enhance collateral blood flow, at least in part, via direct effects on vascular endothelial cells.

CXCL10 DNA vaccination prevents spontaneous diabetes through enhanced beta cell proliferation in NOD mice.

CXCL10, a chemokine for Th1 cells, is involved in the pathogenesis of various Th1-dominant autoimmune diseases. Type 1 diabetes is considered to be a Th1-dominant autoimmune disease, and a suppressive effect of CXCL10 neutralization on diabetes development has been reported in a cyclophosphamide-induced accelerated diabetes model through induction of beta cell proliferation. However, intervention in a diabetes model might bring about opposite effects, depending on the timing, amount, or method of treatment. In the present study, we examined the effect of CXCL10 neutralization in a "spontaneous diabetes" model of NOD mice, using CXCL10 DNA vaccination (pCAGGS-CXCL10). pCAGGS-CXCL10 treatment in young NOD mice induced the production of anti-CXCL10 Ab in vivo and suppressed the incidence of spontaneous diabetes, although this treatment did not inhibit insulitis or alter the immunological response. pCAGGS-CXCL10 treatment enhanced the proliferation of pancreatic beta cells, resulting in an increase of beta cell mass in this spontaneous diabetes model as well. Therefore, CXCL10 neutralization is suggested to be useful for maintaining beta cell mass at any stage of autoimmune diabetes.

The combined CXCR1/CXCR2 antagonist CXCL8(3-74)K11R/G31P blocks neutrophil infiltration, pyrexia, and pulmonary vascular pathology in endotoxemic animals.

CXC chemokine receptor 2 (CXCR2) antagonism alone can reduce neutrophil infiltration of some inflammatory sites, but the CXCR1 and CXCR2 critically regulate neutrophil responses to Glu-Leu-Arg-CXC chemokines. Herein, we assessed a combined CXCR1/CXCR2 antagonist, CXC chemokine ligand 8(3-74) [CXCL8(3-74)]K11R/G31P, for its ability to blunt neutrophil-influx and ancillary pathology in severe endotoxemia. Guinea pigs challenged via the airways with Escherichia coli lipopolysaccharide (LPS; 5 microg/kg) were given CXCL8(3-74)K11R/G31P (subcutaneously) before or after the onset of symptoms. The airways of the LPS-challenged animals contained high levels of endogenous pyrogens interleukin (IL)-1 and tumor necrosis factor (TNF) at 2-4 h, and the animals developed pyrexia, which peaked at approximately 6 h; strong pulmonary, neutrophilic inflammation; and marked pleural hemorrhagic consolidation, as assessed at approximately 15 h. CXCL8(3-74)K11R/G31P treatment before LPS challenge reduced lung pleural hemorrhagic consolidation and airway neutrophilia by >90% and essentially abrogated the IL-1, TNF, and fever responses. When given 3 or 6 h after LPS, CXCL8(3-74)K11R/G31P reduced pulmonary neutrophilia by up to 85% and pleural hemorrhagic consolidation by 50-85%. The 3-h treatment reduced the 6- to 24-h fever response to background. Delays of 6 or 9 h in beginning treatment had significant effects on the fever decay curve, but only the 6-h treatment had a significant effect on the 24-h fever. These results indicate that combined CXCR1/CXCR2 antagonism can have significant therapeutic effects on pulmonary inflammation and hemorrhage, as well as pyrexia in endotoxemic animals.

CXCL11 attenuates bleomycin-induced pulmonary fibrosis via inhibition of vascular remodeling.

Aberrant vascular remodeling is a central hallmark for the development and progression of idiopathic pulmonary fibrosis. The mechanisms underlying the pathophysiologic alterations, however, are poorly understood. A recent phase II trial of interferon gamma-1b has demonstrated a trend toward a decrease in profibrotic and proangiogenic biologic markers, and upregulation of lung CXCL11 mRNA and bronchoalveolar lavage fluid and plasma protein levels of CXCL11. We hypothesized that net aberrant vascular remodeling seen during the pathogenesis of fibroplasia and deposition of extracellular matrix during bleomycin-induced pulmonary fibrosis can be attenuated by treatment with the angiostatic ELR(-) CXC chemokine, CXCL11. In a preclinical model, systemic administration of CXCL11 reduced pulmonary collagen deposition, procollagen gene expression, and histopathologic fibroplasia and extracellular matrix deposition in the lung of bleomycin-treated mice. CXCL11 treatment significantly reduced bleomycin-induced pulmonary fibrosis without altering specific lung leukocyte populations. CXCR3 is not expressed on fibroblasts and CXCL11 had no direct functional effect on pulmonary fibroblasts. The angiogenic activity in the lung was significantly decreased, however, and CXCL11 treatment reduced the total number of endothelial cells in the lung following bleomycin exposure. The results suggest that CXCL11 inhibits pulmonary fibrosis by altering aberrant vascular remodeling.