Effect of the CCL5-Releasing Fibrin Gel for Intervertebral Disc Regeneration

OBJECTIVE

To explore if chemokine (C-C motif) ligand 5 (CCL5) delivery could recruit annulus fibrosus (AF) cells to the injury sites and facilitate the repair of ruptured AF.

DESIGN

The effects of CCL5 on bovine AF cells in vitro were tested by transwell assay and quantitative real-time polymerase chain reaction. Fibrin gel containing CCL5 was used to treat annulotomized bovine caudal discs cultured under dynamic loading conditions. After 14 days of loading, the samples were collected for histological examination. A pilot animal study was performed using sheep cervical discs to investigate the effect of fibrin gel encapsulated with CCL5 for the treatment of ruptured AF. After 14 weeks, the animals were sacrificed, and the discs were scanned with magnetic resonance imaging before histopathological examination.

RESULTS

CCL5 showed a chemotactic effect on AF cells in a dose-dependent manner. AF cells cultured with CCL5 in vitro did not show any change of the gene expression of CCL5 receptors, catabolic and proinflammatory markers. In vitro release study showed that CCL5 exhibited sustained release from the fibrin gel into the culture media; however, in the organ culture study CCL5 did not stimulate homing of AF cells toward the defect sites. The pilot animal study did not show any repair effect of CCL5.

CONCLUSIONS

CCL5 has a chemotactic effect on AF cells in vitro, but no ex vivo or in vivo regenerative effect when delivered within fibrin gel. Further study with a stronger chemotactic agent and/or an alternate biomaterial that is more conductive of cell migration is warranted.

CD133+ ovarian cancer stem-like cells promote non-stem cancer cell metastasis via CCL5 induced epithelial-mesenchymal transition

Cancer stem cells (CSCs, also called cancer stem-like cells, CSLCs) can function as "seed cells" for tumor recurrence and metastasis. Here, we report that, in the presence of CD133+ ovarian CSLCs, CD133- non-CSLCs can undergo an epithelial-mesenchymal transition (EMT)-like process and display enhanced metastatic capacity in vitro and in vivo. Highly elevated expression of chemokine (C-C motif) ligand 5 (CCL5) and its receptors chemokine (C-C motif) receptor (CCR) 1/3/5 are observed in clinical and murine metastatic tumor tissues from epithelial ovarian carcinomas. Mechanistically, paracrine CCL5 from ovarian CSLCs activates the NF-κB signaling pathway in ovarian non-CSLCs via binding CCR1/3/5, thereby inducing EMT and tumor invasion. Taken together, our results redefine the metastatic potential of non-stem cancer cells and provide evidence that targeting the CCL5:CCR1/3/5-NF-κB pathway could be an effective strategy to prevent ovarian cancer metastasis.

Loss of Gab1 adaptor protein in hepatocytes aggravates experimental liver fibrosis in mice

Grb2-associated binder 1 (Gab1) adaptor protein amplifies signals downstream of a broad range of growth factors/receptor tyrosine kinases. Although these signals are implicated in liver fibrogenesis, the role of Gab1 remains unclear. To elucidate the role of Gab1, liver fibrosis was examined in hepatocyte-specific Gab1-conditional knockout (Gab1CKO) mice upon bile duct ligation (BDL). Gab1CKO mice developed exacerbated liver fibrosis with activation of hepatic myofibroblasts after BDL compared with control mice. The antifibrotic role of hepatocyte Gab1 was further confirmed by another well-established mouse model of liver fibrosis using chronic injections of carbon tetrachloride. After BDL, Gab1CKO mice also displayed exacerbated liver injury, decreased hepatocyte proliferation, and enhanced liver inflammation. Furthermore, cDNA microarray analysis was used to investigate the potential molecular mechanisms of the Gab1-mediated signal in liver fibrosis, and the fibrosis-promoting factor chemokine (C-C motif) ligand 5 (Ccl5) was identified as upregulated in the livers of Gab1CKO mice following BDL. Interestingly, in vitro studies using primary hepatocytes isolated from control and Gab1CKO mice revealed that the loss of Gab1 resulted in increased hepatocyte CCL5 synthesis upon lipopolysaccharide stimulation. Finally, pharmacological antagonism of CCL5 reduced BDL-induced liver fibrosis in Gab1CKO mice. In conclusion, our results demonstrate that hepatocyte Gab1 is required for liver fibrosis and that hepatocyte CCL5 could be an important contributor to this process. Thus, we present a novel antifibrotic function of hepatocyte Gab1 in liver fibrogenesis.

Selective inhibition of sphingosine kinase-1 protects adipose tissue against LPS-induced inflammatory response in Zucker diabetic fatty rats

Obesity is associated with a state of chronic inflammation. The chemokine (C-C motif) ligand 5 (CCL5) has been proposed to modulate the inflammatory response in adipose tissue (AT). However, the mechanisms underlying CCL5 upregulation in AT remain undefined. The objective of the present study was to evaluate whether the enzyme sphingosine kinase-1 (SK1) would modulate the expression of CCL5 and other inflammatory biomarkers in primary adipocytes and its potential role in lipopolysaccharide (LPS)-induced AT inflammation in a rat model of diabetes. To address this, LPS-stimulated primary adipocytes and 3T3-L1 cells were treated with a SK inhibitor, and the expression of Ccl5 and other CC chemokines were studied. Moreover, the effect of SK1 knockdown on cytokine production was analyzed in 3T3-L1 cells by transfection of SK1-specific small-interfering RNA (siRNA). The anti-inflammatory effects of SK inhibitor in AT were also investigated in vivo using the Zucker lean normoglycemic control (ZLC) rats. LPS treatment stimulated Ccl5, IL-6, pentraxin 3 (Ptx3), and Tnfα mRNA expression in primary adipocytes and 3T3-L1 cells, whereas pharmacologically and siRNA-mediated SK1 inhibition strongly reduced mRNA levels of proinflammatory cytokines in these cells. Similarly, administration of SK inhibitor to ZLC rats prevented the LPS-induced inflammatory response in AT. Our data demonstrate a role for SK1 in endotoxin-induced cytokine expression in adipocytes and suggest that inhibition of SK1 may be a potential therapeutic tool in the prevention and treatment of chronic and common metabolic disorders, including obesity, insulin-resistance, and type 2 diabetes.

The chemokine CCL5 induces CCR1-mediated hyperalgesia in mice inoculated with NCTC 2472 tumoral cells

Although the expression of the chemokine receptor CCR1 has been demonstrated in several structures related to nociception, supporting the nociceptive role of chemokines able to activate it, the involvement of CCR1 in neoplastic pain has not been previously assessed. We have assayed the effects of a CCR1 antagonist, J113863, in two murine models of neoplastic hyperalgesia based on the intratibial injection of either NCTC 2472 fibrosarcoma cells, able to induce osteolytic bone injury, or B16-F10 melanoma cells, associated to mixed osteolytic/osteoblastic bone pathological features. The systemic administration of J113863 inhibited thermal and mechanical hyperalgesia but not mechanical allodynia in mice inoculated with NCTC 2472 cells. Moreover, in these mice, thermal hyperalgesia was counteracted following the peritumoral (10-30μg) but not spinal (3-5μg) administration of J113863. In contrast, hyperalgesia and allodynia measured in mice inoculated with B16-F10 cells remained unaffected after the administration of J113863. The inoculation of tumoral cells did not modify the levels of CCL3 at tumor or spinal cord. In contrast, although the concentration of CCL5 remained unmodified in mice inoculated with B16-F10 cells, increased levels of this chemokine were measured in tumor-bearing limbs, but not the spinal cord, of mice inoculated with NCTC 2472 cells. Increased levels of CCL5 were also found following the incubation of NCTC 2472, but not B16-F10, cells in the corresponding culture medium. The intraplantar injection of CCL5 (0.5ng) to naïve mice evoked thermal hyperalgesia prevented by the coadministration of J113863 or the CCR5 antagonist, d-Ala-peptide T-amide (DAPTA), demonstrating that CCL5 can induce thermal hyperalgesia in mice through the activation of CCR1 or CCR5. However, contrasting with the inhibitory effect evoked by J113863, the systemic administration of DAPTA did not prevent tumoral hyperalgesia. Finally, the peritumoral administration of an anti-CCL5 antibody completely inhibited thermal hyperalgesia evoked by the inoculation of NCTC 2472 cells.

No association between genetic variants in angiogenesis and inflammation pathway genes and breast cancer survival among Chinese women

BACKGROUND

Angiogenesis and inflammation are implicated in breast cancer prognosis; however, the role of individual germline variation in related genes is unknown.

METHODS

A two-stage candidate pathway association study was conducted among 6983 Chinese women. Stage 1 included 2884 women followed for a median of 5.7 years; Stage 2 included 4099 women followed for a median of 4.0 years. Cox proportional hazards regression was used to estimate the effects of genetic variants on disease-free survival (DFS) and overall survival (OS).

RESULTS

Stage 1 included genotyping of 506 variants in 22 genes; analysis was conducted for 370 common variants. Nominally significant associations with DFS and/or OS were found for 20 loci in ten genes in Stage 1; variants in 19 loci were successfully genotyped and evaluated in Stage 2. In analyses of both study stages combined, nominally significant associations were found for nine variants in seven genes; none of these associations surpassed a significance threshold level corrected for the total number of variants evaluated in this study.

CONCLUSIONS

No association with survival was found for 370 common variants in 22 angiogenesis and inflammation pathway genes among Chinese women with breast cancer.

IMPACT

Our data do not support a large role for common genetic variation in 22 genes in breast cancer prognosis; research on angiogenesis and inflammation genes should focus on common variation in other genes, rare host variants, or tumor alterations.