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

BACKGROUNDMucus hypersecretion in the respiratory tract and goblet cell metaplasia in the airway epithelium contribute to the morbidity and mortality associated with airway inflammatory diseases. This study aimed to examine the effect and mechanisms of simvastatin on airway mucus hypersecretion in rats treated with lipopolysaccharide (LPS).

METHODSMucus hypersecretion in rat airways was induced by intra-tracheal instillation of LPS. Rats treated with or without LPS were administered intra-peritoneally simvastatin (5 and 20 mg/kg) for 4 days. Expression of Muc5ac, RhoA and mitogen-activated protein kinases (MAPK) p38 in lung were detected by real-time polymerase chain reaction (PCR), immunohistochemistry or Western blotting. Tumor necrosis factor (TNF)-alpha and IL-8 in bronchoalveolar lavage fluid (BALF) were assayed by an enzyme-linked lectin assay and enzyme linked immunosorbent assay (ELISA).

RESULTSSimvastatin attenuated LPS-induced goblet cell hyperplasia in bronchial epithelium and Muc5ac hypersecretion at both the gene and protein levels in lung (P <0.05). Moreover, simvastatin inhibited neutrophil accumulation and the increased concentration of TNF-alpha and IL-8 in BALF follows LPS stimulation (P < 0.05). The higher dose of simvastatin was associated with a more significant reduction in Muc5ac mRNA expression, neutrophil accumulation and inflammatory cytokine release. Simultaneously, the increased expression of RhoA and p38 MAPK were observed in LPS-treated lung (P <0.05). Simvastatin inhibited the expression of RhoA and p38 phosphorylation in lung following LPS stimulation (P < 0.05). However, the increased expression of p38 protein in LPS-treated lung was not affected by simvastatin administration.

CONCLUSIONSSimvastatin attenuates airway mucus hypersecretion and pulmonary inflammatory damage induced by LPS. The inhibitory effect of simvastatin on airway mucus hypersecretion may be through, at least in part, the suppression of neutrophil accumulation and inflammatory cytokine release via inactivation of RhoA and p38 signaling pathway.

Animals ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; pharmacology ; Lipopolysaccharides ; toxicity ; Male ; Mucin 5AC ; secretion ; Rats ; Rats, Sprague-Dawley ; Respiratory Mucosa ; drug effects ; secretion ; Simvastatin ; pharmacology ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; rhoA GTP-Binding Protein ; antagonists & inhibitors

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 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

Actins ; chemistry ; Amides ; therapeutic use ; Animals ; Apoptosis ; drug effects ; Cytoskeleton ; drug effects ; Enzyme Inhibitors ; therapeutic use ; Female ; Liver Neoplasms, Experimental ; drug therapy ; pathology ; Mice ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Pyridines ; therapeutic use ; ras Proteins ; analysis ; rho-Associated Kinases ; analysis ; antagonists & inhibitors ; rhoA GTP-Binding Protein ; analysis ; rhoC GTP-Binding Protein

Agents that elevate cellular cAMP are known to inhibit the activation of phospholipase D (PLD). We investigated whether PLD can be phosphorylated by cAMP-dependent protein kinase (PKA) and PKA-mediated phosphorylation affects the interaction between PLD and RhoA, a membrane regulator of PLD. PLD1, but not PLD2 was found to be phosphorylated in vivo by the treatment of dibutyryl cAMP (dbcAMP) and in vitro by PKA. PKA inhibitor (KT5720) abolished the dbcAMP-induced phosphorylation of PLD1, but dibutyryl cGMP (dbcGMP) failed to phosphorylate PLD1. The association between PLD1 and Val14RhoA in an immunoprecipitation assay was abolished by both dbcAMP and dbcGMP. Moreover, RhoA but not PLD1 was dissociated from the membrane to the cytosolic fraction in dbcAMP-treated cells. These results suggest that both PLD1 and RhoA are phosphorylated by PKA and the interaction between PLD1 and RhoA is inhibited by the phosphorylation of RhoA rather than by the phosphorylation of PLD1.
Bucladesine/pharmacology ; Carbazoles/pharmacology ; Cell Line, Tumor ; Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors/*metabolism ; Dibutyryl Cyclic GMP/pharmacology ; Enzyme Inhibitors/pharmacology ; Humans ; Indoles/pharmacology ; Phospholipase D/*metabolism ; Phosphorylation/drug effects ; Pyrroles/pharmacology ; Research Support, Non-U.S. Gov't ; rhoA GTP-Binding Protein/*metabolism

Sphingosylphosphorylcholine (SPC) induces differentiation of human adipose tissue-derived mesenchymal stem cells (hASCs) into smooth muscle-like cells expressing alpha-smooth muscle actin (alpha-SMA) via transforming growth factor-beta1/Smad2- and RhoA/Rho kinase-dependent mechanisms. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) have been known to have beneficial effects in the treatment of cardiovascular diseases. In the present study, we examined the effects of simvastatin on the SPC-induced alpha-SMA expression and Smad2 phosphorylation in hASCs. Simvastatin inhibited the SPC-induced alpha-SMA expression and sustained phosphorylation of Smad2 in hASCs. SPC treatment caused RhoA activation via a simvastatin-sensitive mechanism. The SPC-induced alpha-SMA expression and Smad2 phosphorylation were abrogated by pretreatment of the cells with the Rho kinase inhibitor Y27632 or overexpression of a dominant negative RhoA mutant. Furthermore, SPC induced secretion of TGF-beta1 and pretreatment with either Y27632 or simvastatin inhibited the SPC-induced TGF-beta1 secretion. These results suggest that simvastatin inhibits SPC-induced differentiation of hASCs into smooth muscle cells by attenuating the RhoA/Rho kinase-dependent activation of autocrine TGF-beta1/Smad2 signaling pathway.
Amides/pharmacology ; Blotting, Western ; Cell Differentiation/*drug effects ; Cells, Cultured ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunohistochemistry ; Mesenchymal Stem Cells/*cytology/*drug effects ; Myocytes, Smooth Muscle/*cytology/*drug effects ; Phosphorylcholine/*analogs & derivatives/pharmacology ; Pyridines/pharmacology ; Simvastatin/*pharmacology ; Sphingosine/*analogs & derivatives/pharmacology ; rhoA GTP-Binding Protein/antagonists & inhibitors/metabolism

BACKGROUNDThe RhoA/Rho kinase pathway may participate in the pathogenesis of hypoxia and monocrotaline induced pulmonary hypertension. This study tested whether RhoA/Rho kinase pathway is involved in the pathogenesis of high flow induced pulmonary hypertension in rats.

METHODSMale Wistar rats (4 weeks) were randomly divided into 4 shunt groups, 4 treated groups and 4 control groups. Shunt and treated groups underwent left common carotid artery/external jugular vein shunt operation. Control groups underwent sham operation. Treated groups received fasudil treatment and the others received same dose of saline. At weeks 1, 2, 4 and 8 of the study, right ventricular systolic pressure was measured and blood gases were analysed to calculate Qp/Qs. The weight ratio of right ventricle to left ventricle plus septum and the mean percentage of medial wall thickness in moderate sized pulmonary arteries were obtained. RhoA activity in pulmonary arteries was detected using Rho activity assay reagent. Rho kinase activity was quantified by the extent of MYPT1 phosphorylation with Western blot. Proliferating cells were evaluated using proliferating cell nuclear antigen immunohistological staining.

RESULTSCarotid artery/jugular vein shunt resulted in high pulmonary blood flow, both an acute and a chronic elevation of right ventricular systolic pressure, significant medial wall thickening characterized by smooth muscle cells proliferation, right ventricular hypertrophy and increased activation of RhoA and Rho kinase. Fasudil treatment lowered pulmonary artery systolic pressure, suppressed pulmonary artery smooth muscle cells proliferation, attenuated pulmonary artery medial wall thickening and inhibited right ventricular hypertrophy together with significant suppression of Rho kinase activity but not Rho activity.

CONCLUSIONSActivated RhoA/Rho kinase pathway is associated with both the acute pulmonary vasoconstriction and the chronic pulmonary artery remodelling of high flow induced pulmonary hypertension. Fasudil treatment could improve pulmonary hypertension by inhibiting Rho kinase activity.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine ; analogs & derivatives ; therapeutic use ; Animals ; Cell Proliferation ; drug effects ; Enzyme Activation ; drug effects ; Hypertension, Pulmonary ; drug therapy ; etiology ; Hypertrophy, Right Ventricular ; prevention & control ; Intracellular Signaling Peptides and Proteins ; antagonists & inhibitors ; physiology ; Male ; Muscle, Smooth, Vascular ; drug effects ; Protein Kinase Inhibitors ; therapeutic use ; Protein-Serine-Threonine Kinases ; antagonists & inhibitors ; physiology ; Pulmonary Artery ; pathology ; Pulmonary Circulation ; drug effects ; Rats ; Rats, Wistar ; Systole ; drug effects ; Vasoconstriction ; drug effects ; rho-Associated Kinases ; rhoA GTP-Binding Protein ; physiology

Rac1 and Rac2 are essential for the control of oxidative burst catalyzed by NADPH oxidase. It was also documented that Rho is associated with the superoxide burst reaction during phagocytosis of serum- (SOZ) and IgG-opsonized zymosan particles (IOZ). In this study, we attempted to reveal the signal pathway components in the superoxide formation regulated by Rho GTPase. Tat-C3 blocked superoxide production, suggesting that RhoA is essentially involved in superoxide formation during phagocytosis of SOZ. Conversely SOZ activated both RhoA and Rac1/2. Inhibition of RhoA-activated kinase (ROCK), an important downstream effector of RhoA, by Y27632 and myosin light chain kinase (MLCK) by ML-7 abrogated superoxide production by SOZ. Extracellular signaling-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK) were activated during phagocytosis of SOZ, and Tat-C3 and SB203580 reduced ERK1/2 and p38 MAPK activation, suggesting that RhoA and p38 MAPK may be upstream regulators of ERK1/2. Inhibition of ERK1/2, p38 MAPK, phosphatidyl inositol 3-kinase did not block translocation of RhoA to membranes, suggesting that RhoA is upstream to these kinases. Inhibition of RhoA by Tat-C3 blocked phosphorylation of p47 PHOX. Taken together, RhoA, ROCK, p38MAPK, ERK1/2, and p47 PHOX may be subsequently activated, leading to activation of NADPH oxidase to produce superoxide.
Animals ; Cell Line ; Cell Membrane ; Cytosol ; Enzyme Inhibitors/pharmacology ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Macrophage-1 Antigen/pharmacology ; Macrophages/drug effects/*metabolism/ultrastructure ; Mice ; Myosin-Light-Chain Kinase/metabolism ; Opsonin Proteins/blood/*metabolism ; *Phagocytosis ; Protein Transport ; Protein-Serine-Threonine Kinases/metabolism ; Research Support, Non-U.S. Gov't ; *Signal Transduction ; Superoxides/*metabolism ; Tetradecanoylphorbol Acetate/pharmacology ; Zymosan/*blood ; p38 Mitogen-Activated Protein Kinases/metabolism ; rhoA GTP-Binding Protein/antagonists & inhibitors/*metabolism