Horse Chestnut Extract Induces Contraction Force Generation in Fibroblasts through Activation of Rho/Rho Kinase

Aesculus hippocastanum L. Extract Does Not Induce Fibroblast to Myofibroblast Conversion but Increases Extracellular Matrix Production In Vitro Leading to Increased Wound Tensile Strength in Rats

The ability of horse chestnut extract (HCE) to induce contraction force in fibroblasts, a process with remarkable significance in skin repair, motivated us to evaluate its wound healing potential in a series of experiments. In the in vitro study of the ability of human dermal fibroblasts to form myofibroblast-like cells was evaluated at the protein level (Western blot and immunofluorescence). The in vivo study was conducted on male Sprague-Dawley rats with inflicted wounds (one open circular and one sutured incision) on their backs. Rats were topically treated with two tested HCE concentrations (0.1% and 1%) or sterile water. The control group remained untreated. The incisions were processed for wound tensile strength (TS) measurement whereas the open wounds were subjected to histological examination. On the in vitro level the HCE extract induced fibronectin-rich extracellular matrix formation, but did not induced α-smooth muscle actin (SMA) expression in dermal fibroblasts. The animal study revealed that HCE increased wound TS and improved collagen organization. In conclusion, the direct comparison of both basic wound models demonstrated that the healing was significantly increased following HCE, thus this extract may be found useful to improve healing of acute wounds. Nevertheless, the use of an experimental rat model warrants a direct extrapolation to the human clinical situation.

Nonmuscle myosin is regulated during smooth muscle contraction

The participation of nonmuscle myosin in force maintenance is controversial. Furthermore, its regulation is difficult to examine in a cellular context, as the light chains of smooth muscle and nonmuscle myosin comigrate under native and denaturing electrophoresis techniques. Therefore, the regulatory light chains of smooth muscle myosin (SM-RLC) and nonmuscle myosin (NM-RLC) were purified, and these proteins were resolved by isoelectric focusing. Using this method, intact mouse aortic smooth muscle homogenates demonstrated four distinct RLC isoelectric variants. These spots were identified as phosphorylated NM-RLC (most acidic), nonphosphorylated NM-RLC, phosphorylated SM-RLC, and nonphosphorylated SM-RLC (most basic). During smooth muscle activation, NM-RLC phosphorylation increased. During depolarization, the increase in NM-RLC phosphorylation was unaffected by inhibition of either Rho kinase or PKC. However, inhibition of Rho kinase blocked the angiotensin II-induced increase in NM-RLC phosphorylation. Additionally, force for angiotensin II stimulation of aortic smooth muscle from heterozygous nonmuscle myosin IIB knockout mice was significantly less than that of wild-type littermates, suggesting that, in smooth muscle, activation of nonmuscle myosin is important for force maintenance. The data also demonstrate that, in smooth muscle, the activation of nonmuscle myosin is regulated by Ca(2+)-calmodulin-activated myosin light chain kinase during depolarization and a Rho kinase-dependent pathway during agonist stimulation.

Metastin inhibits migration and invasion of renal cell carcinoma with overexpression of metastin receptor

BACKGROUND

Metastin, the final peptide of the KiSS-1 gene, has been proposed to suppress cell motility.

OBJECTIVE

This study investigated whether renal cell carcinoma (RCC) tissue expresses metastin or its receptor, and clarified whether metastin can suppress migration and/or invasion and/or proliferation of RCC cells in vitro.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-five RCC samples were submitted. Fresh RCC tissues were prepared for real-time RT-PCR, and formalin-fixed and paraffin-embedded tissues blocks were examined by immunohistochemistry. RCC cell lines Caki-1 and ACHN were supplied for cell migration, invasion, and proliferation assays.

MEASUREMENTS

Real-time RT-PCR was performed by using Taq Man gene expression system. ENVISION system was used in immunohistochemistry. Wound-healing assay and matrigel assays were used to identify migration and invasion abilities of RCC cell lines. Cell Counting Kit-8 was applied to measure the cell proliferation. Cell morphology was examined under a META system. Statistical analysis was performed with SPSS15.0J.

RESULTS AND LIMITATIONS

In twenty-five RCC samples, the mRNA level of metastin receptor was identified to be significantly higher than non-neoplastic renal cortex by real-time RT-PCR (p=0.011). Immunohistochemical study also detected metastin receptor protein in all RCC tumors. In vitro, this study showed that metastin inhibited migration and invasion of Caki-1 and ACHN cells. In contrast, it had no effects on cell proliferation. Metastin (10 micromol/l) induced excessive formation of focal adhesions and stress fibers in Caki-1 and ACHN cells; this phenomenon was inhibited by pretreating pharmacological Rho-kinase inhibitor (Y-27632) to those cells.

CONCLUSION

This is the first report regarding overexpression of the metastin receptor hOT7T175 in human RCC. We demonstrate that metastin can inhibit migration and invasion of the RCC cell line, which is regulated by a Rho-kinase inhibitor. Metastin and its receptor are therefore probable targets for suppressing RCC.