Erectile dysfunction (ED) has been plaguing men for a long time and the incidence of this disease is as high as 52% among males aged between 40 and 70. Recent discovery has shown a connection between the RhoA/Rho-kinase signaling system and ED. This paper reviews the progress in the study of RhoA/Rho-kinase signaling pathway, expounds its mechanism in penile erection and provides a base for further research on the role of RhoA/Rho-kinase signaling pathway in penile erection.
Animals ; Humans ; Male ; Penile Erection ; physiology ; Rabbits ; Signal Transduction ; physiology ; rho-Associated Kinases ; metabolism ; rhoA GTP-Binding Protein ; metabolism

As a neuropeptide, neurotensin (NTS) is widely expressed in central and peripheral nervous system, which is mainly mediated byneurotensin receptor1 (NTSR1) to activate the related downstream signaling pathways. After summarized the function and mechanism of NTS/NTSR1 in various malignant tumors, we found that NTS/NTSR1 played essential roles during tumor initiation and development. NTS/NTSR1 regulates tumor initiation, proliferation, apoptosis, metastasis and differentiation mainly through three pathways, including IP3/Ca2+ /PKC/MAPKs pathway, MMPs/EGFR/MAPKs (PI3K/Akt) pathway, or Rho-GTPsaes and non-receptor tyrosine kinase pathway. Besides, NTS/NTSR1 is also regulated by some upstream pathways and some traditional Chinese medicine preparations and traditional Chinese medicine therapies. In this article, we summarized the function of NTS/NTSR1 and its mechanisms, and discussed the prospective in its application to clinical diagnosis and drugs targeting.
Animals ; Humans ; Medicine, Chinese Traditional ; Neoplasms ; etiology ; Neurotensin ; chemistry ; physiology ; Receptor, Epidermal Growth Factor ; physiology ; Receptors, Neurotensin ; chemistry ; physiology ; Signal Transduction ; physiology ; rhoA GTP-Binding Protein ; physiology

OBJECTIVETo study the expression and possible function of RhoA in human gastric cancer cell lines.

METHODSThe expression of RhoA in human gastrointestinal cancer cell lines was detected by Western blot. Antisense plasmid of RhoA was constructed by pGEFL and transferred into gastric cancer cell line AGS by lipofectamine. Cell survival was examined by MTT assays, and cell cycle was detected by flow cytometry.

RESULTSThe expression of RhoA protein in 10 different kinds of human cancer cell lines was much higher than that in immortalized human intestinal epithelial cell line. After being transfected with antisense RhoA, with the decrease in RhoA protein expression, the growth rate of AGS was inhibited, and the number of cells in S phase was increased by 14%.

CONCLUSIONRhoA is overexpressed in many human cancer cell lines. Some of the malignant characteristics of a gastric cancer cell line can be partially reversed by inhibiting RhoA expression.

Antisense Elements (Genetics) ; pharmacology ; Cell Cycle ; Cell Line, Tumor ; Genetic Therapy ; Humans ; Stomach Neoplasms ; chemistry ; pathology ; therapy ; rhoA GTP-Binding Protein ; analysis ; antagonists & inhibitors ; physiology

The erectile response of the penis depends on a balance between vasoconstrictor agents, which cause cavernosal smooth muscle to contract limiting blood inflow, and vasodilators, which relax cavernosal smooth muscle leading to increased blood inflow and erection. This review emphasizes the role of the RhoA/Rho-kinase pathway in the cavernosal circulation. While it is widely held that the nitric oxide-cyclic GMP-protein kinase G(NO-cGMP-PKG) pathway mediates vasorelaxation and penile erection, the vasoconstrictor actions of endothelin ET-1 and NE are reported to be mediated by the RhoA/Rho-kinase pathway in the cavernosal circulation and NO relax cavernosal smooth by inhibition of Rho-kinase. The application of Rho-kinase inhibitor on the penile erection may represent a new and promising method of treatment for erectile dysfunction.
Animals ; Erectile Dysfunction ; physiopathology ; Humans ; Intracellular Signaling Peptides and Proteins ; physiology ; Male ; Nitric Oxide ; physiology ; Penile Erection ; physiology ; Protein-Serine-Threonine Kinases ; physiology ; rho-Associated Kinases ; rhoA GTP-Binding Protein ; physiology

BACKGROUNDAfter injury, axonal regeneration of the adult central nervous system (CNS) is inhibited by myelin-derived growth-suppressing proteins. These axonal growth inhibitory proteins are mediated via activation of Rho, a small GTP-binding protein. The activated form of Rho, which is bound to GTP, is the direct activator of Rho kinase (ROCK) through serial downstream effector proteins to inhibit axonal regeneration. The objective of this study was to observe the therapeutic effect of inactivation of the Rho-ROCK signaling pathway to promote neurologic recovery after spinal cord injuries in rats.

METHODSOne hundred and twenty adult female Sprague-Dawley rats were randomly divided into three groups. Laminectomies alone were conducted in 40 rats in the sham group. Laminectomies and spinal cord transections were performed in 40 rats in the control group (treated with normal saline administered intraperitoneally). Laminectomies and spinal cord transections were performed in 40 rats in the fasudil-treated group (treated with fasudil administered intraperitoneally). Neurologic recovery was evaluated before surgery and 3 days, and 1, 2, 3, and 4 weeks after surgery using the Basso-Beattie-Bresnahan (BBB) scale of hind limb movement. At the same time, the expression of RhoA mRNA was determined with RT-PCR. Histopathologic examinations and immunofluorescence staining of NF were performed 1 month after surgery.

RESULTSCompared with the control group, the BBB scores of the fasudil-treated group were significantly increased and the expression of RhoA mRNA was significantly decreased. In the fasudil-treated group, a large number of NF-positive regenerating fibers was observed; some fibers crossed the slit of the lesion.

CONCLUSIONInactivation of the Rho-ROCK signaling pathway promotes CNS axonal regeneration and neurologic recovery after spinal cord injuries in rats.

Animals ; Female ; Fluorescent Antibody Technique ; Nerve Regeneration ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; physiology ; Spinal Cord Injuries ; pathology ; physiopathology ; psychology ; therapy ; rho-Associated Kinases ; antagonists & inhibitors ; physiology ; rhoA GTP-Binding Protein ; antagonists & inhibitors ; physiology

OBJECTIVETo investigate the role of dietary capsaicin in activating transient receptor potential vanilloid 1 (TRPV1) and thus influencing the vascular dysfunction mediated by high-fat diet and the potential mechanisms.

METHODSA total of 80 male C57BL/6J mice aged 10 weeks were equally divided into four groups, in which the mice were fed with normal diet (ND), normal diet plus capsaicin (NC), high-fat diet (HD), or high-fat diet plus capsaicin (HC) for 20 weeks. Tail-cuff blood pressure (BP), vascular function of mice aortic rings, expressions of voltage-gated potassium-channel Kv1.4, RhoA and Rho kinase in aorta were examined.

RESULTSCompared with ND group, both nitroglycerin [(18.9 +/- 13)% vs. 100%, P < 0.01] and acetylcholine [(26 +/- 12)% vs. 100%, P < 0.01] induced vasorelaxation of aortic rings were significantly reduced in HD group. Both endothelium dependent and independent aortic rings vasorelaxation in HC group were significantly improved compared with that in HD group [acetylcholine: (69 +/- 15)%; nitroglycerin: (46.5 +/- 6)%, P < 0.05], but still reduced compared with that in ND group (P < 0.05, P < 0.01). High fat diet induced the expression of RhoA and Rho kinase. Dietary capsaicin down-regulated the expression of RhoA and Rho kinase but up-regulated the expression of Kv1.4 in aorta in mice fed with normal or high fat diet (all P < 0.05).

CONCLUSIONDietary capsaicin can ameliorate vasorelaxation dysfunction mediated by high-fat diet. The potential mechanisms may be related with TRPV1 activation, which in turn stimulates potassium channel and inhibits RhoA and Rho kinase in the vasculature.

Animals ; Aorta ; drug effects ; metabolism ; physiology ; Capsaicin ; pharmacology ; Diet, High-Fat ; adverse effects ; Endothelium, Vascular ; metabolism ; physiology ; Male ; Mice ; Mice, Inbred C57BL ; TRPV Cation Channels ; drug effects ; Vasodilation ; drug effects ; physiology ; rho-Associated Kinases ; metabolism ; rhoA GTP-Binding Protein ; metabolism

Previously, we demonstrated that the p190 Rho guanine nucleotide exchange factor (p190RhoGEF) was induced following CD40 stimulation of B cells. In this study, we examined whether p190RhoGEF and a downstream effector molecule RhoA are required for B cell differentiation. Expression of p190RhoGEF positively correlated with the expression of surface markers and transcriptional regulators that are characteristic of mature B cells with plasma cell (PC) phenotypes. Moreover, either the overexpression of p190RhoGEF or the expression of a constitutively active RhoA drove cellular differentiation toward PC phenotypes. B cell maturation was abrogated in cells that overexpressed p190RhoGEF and a dominant-negative form of RhoA simultaneously. CD40-mediated maturation events were also abrogated in cells that overexpressed either dominant-negative p190RhoGEF or RhoA. Together, these data provide evidence that p190RhoGEF signaling through RhoA in CD40-activated B cells drives the induction of the PC differentiation.
Animals ; B-Lymphocytes/*cytology/*metabolism ; Cell Differentiation/genetics/*physiology ; Cell Line ; Cells, Cultured ; Female ; Guanine Nucleotide Exchange Factors/genetics/*metabolism ; Humans ; Lymphocyte Activation/genetics/*physiology ; Mice ; Mice, Inbred BALB C ; Plasma Cells/*cytology/*metabolism ; rhoA GTP-Binding Protein/genetics/metabolism

OBJECTIVETo reveal the roles of Rho kinase (ROCK) in the mechanisms of complications in diabetes by reviewing the correlations between ROCK and related complications in diabetes.

DATA SOURCESThe data used in the present article were mainly from PubMed with relevant English articles published from 1998 to 2010. The search terms were "ROCK" and "diabetes".

STUDY SELECTIONOriginal articles including the roles of ROCK or its inhibitors in diabetic complications and review articles about the biological character of ROCK were selected.

RESULTSThe activity and expression of ROCK were up-regulated in the models of type 1 or type 2 diabetes animals and the cultured cells with concentrations of high glucose, ROCK activation was associated with the development or progression of complications in diabetes. Inhibition of RhoA/ROCK pathway prevented or ameliorated the pathologic changes of diabetic complications, and ROCK has been regarded as a key target for treatment of these complications.

CONCLUSIONRhoA/ROCK signaling plays important roles in the pathogenesis of long-term complications in diabetes and ROCK inhibitors are becoming a promising solution to treatments of complications in diabetes.

Animals ; Cardiomyopathies ; etiology ; Diabetes Complications ; etiology ; therapy ; Humans ; Sexual Dysfunction, Physiological ; etiology ; Signal Transduction ; Urinary Bladder Diseases ; etiology ; rho-Associated Kinases ; antagonists & inhibitors ; chemistry ; physiology ; rhoA GTP-Binding Protein ; antagonists & inhibitors ; chemistry ; physiology

BACKGROUNDWe have recently reported that RhoA may regulate the invasion and metastasis of breast cancer cells as an upstream signal of ezrin in vitro. In this study, we examined the relationship of RhoA signaling activity with ezrin expression in breast cancer and its prognostic significance in patients with breast cancer.

METHODSParaffin tumor sections of breast cancer were collected retrospectively from 487 patients diagnosed between 2001 and 2004. Immunohistochemical methods were used to detect the expression of RhoA, phosphorylated (activated) RhoA, and ezrin.

RESULTSEzrin overexpression was detectable in 15.2% of 487 invasive breast cancers. The majority (85.1%) of ezrin-overexpressing tumors coexpressed phosphorylated RhoA; 78.8% of tumors with phosphorylated RhoA cooverexpressed ezrin. Patients whose cancers showed overexpression of ezrin or expression of phosphorylated RhoA had shorter survival rates.

CONCLUSIONSRhoA activation is important in human breast cancer due to its upregulation of ezrin; thus, agents that target phosphorylated RhoA may be useful in the treatment of tumors with ezrin overexpression.

Adult ; Aged ; Breast Neoplasms ; chemistry ; mortality ; Cytoskeletal Proteins ; analysis ; Female ; Humans ; Middle Aged ; Phosphorylation ; Prognosis ; Proportional Hazards Models ; Retrospective Studies ; Signal Transduction ; physiology ; Survival Rate ; rhoA GTP-Binding Protein ; analysis ; physiology

RhoA is one of the main members of RhoGTPase family involved in cell morphology, smooth muscle contraction, cytoskeletal microfilaments and stress fiber formation. It has been demonstrated that RhoA modulates endothelial cell permeability by its effect on F-actin rearrangement, but the molecular mechanism of rearrangement of actin cytoskeleton remains unclear. Recent studies prove that RhoA/Rho kinase regulates smooth muscle specific actin dynamics by activating serum response factor (SRF)-dependent transcription. To further investigate the molecular mechanism of the rearrangement of vascular endothelial cell actin cytoskeleton, we explored the relationship between the activation of SRF and F-actin rearrangement induced by RhoA in human umbilical vein endothelial cells (HUVECs). HUVECs were infected with the constitutively active forms of RhoA (Q63LRhoA) or the dominant negative forms of RhoA(T19NRhoA) using retrovirus vector pLNCX-Q63LRhoA or pLNCX-T19NRhoA, the positive clone was obtained by G418 selection. The expression and distribution of SRF in normal and infected cells were evaluated by immunohistochemistry and Western blot in complete medium and in serum-free medium. The effect of F-actin polymerization was detected by Rhodamine-Phalloidine staining. Infection of PLNCX-Q63LRhoA induced F-actin rearrangement and stress fiber formation in HUVECs, as well as enhanced the expression of SRF in the nuclei. In contrast, the cells infected with T19NRhoA showed no distinct changes. With serum deprivation, the expression of SRF increased obviously in both normal and infected HUVECs, but the subcellular localization of SRF was evidently different. In HUVECs, the localization of SRF was in the nuclei after 3 d with serum deprivation, but it was redistributed outside the nuclei after 5 d with serum deprivation. In cells infected with Q63LRhoA, the immunolocalization of SRF was always in the nuclei compared with HUVECs infected with T19NRhoA, which was almost always localized in the cytoplasm. In HUVECs, the rearrangement of F-actin and formation of stress fiber increased after 3 d with serum deprivation, but appeared decreased and unpolymerized after 5 d with serum deprivation. The polymerization of F-actin and the formation of stress fiber in HUVECs infected with Q63LRhoA kept during the period of serum-free culture, whereas the rearrangement of F-actin in cells infected with T19NRhoA was not found. These results suggest that RhoA influences endothelial F-actin rearrangement in part by regulating the expression and subcellular localization of SRF.
Actins ; biosynthesis ; genetics ; Cytoskeleton ; metabolism ; Endothelium, Vascular ; cytology ; metabolism ; Humans ; Intracellular Signaling Peptides and Proteins ; Protein-Serine-Threonine Kinases ; metabolism ; Serum Response Factor ; biosynthesis ; genetics ; Umbilical Veins ; cytology ; rho-Associated Kinases ; rhoA GTP-Binding Protein ; physiology