OBJECTIVE: To investigate the regulation mechanism of RhoA signaling pathway during the enamel formation by using the EGFP-RhoA^{Dominant Negative} (EGFP-RhoA^DN) transgenic mice model, from the aspect of adherens junctions, and to provide a theory basis for mechanism of enamel development defects. METHODS: The enamel thickness of mandibular first molars of EGFP-RhoA^DN transgenic mice and wild type (WT) mice were observed by scanning electronic microscopy at 20 kV, and the enamel thickness of the distal face of the central cusp was measured at 10 locations via analysis by ImageJ (Rasband, 1997-2009). The enamel organs from mandibular first molars from postnatal-4-day (P4) EGFP-RhoA^DN mice and wild type mice were isolated, and the total RNA and protein were extracted from the epithelium of the enamel organs. The expression level of the adherens junctions components in ameloblasts layer of the postnatal-4-day EGFP-RhoA^DN transgenic mice and wild type mice mandibular first molars were detected by real-time PCR and Western blot assay. RESULTS: The EGFP-RhoA^DN transgenic mice had decreased enamel thickness in their bilateral mandibular first molars versus those of control group (n=20), and enamel thickness was (84.60±0.20) μm vs. (106.24±0.24) μm, P<0.05. The protein expressions of E-cadherin, α-E-catenin and pan-cadherin in ameloblasts layer of postnatal-4-day EGFP-RhoA^DN transgenic mice molars were down-regulated, and the protein level of β-catenin in ameloblasts layer of P4 EGFP-RhoA^DN transgenic mice molars was up-regulated. The mRNA level of E-cadherin in ameloblasts layer of P4 EGFP-RhoA^DN transgenic mice molars was down-regulated versus that of WT mice, and the gene expression of E-cadherin was 0.93±0.01 vs. 1.00±0.02, P<0.05. The mRNA level of β-catenin in ameloblasts layer of P4 EGFP-RhoA^DN transgenic mice molars was up-regulated versus that of WT mice, and the gene expression of β-catenin was 1.23±0.03 vs. 1.00±0.05, P<0.05. CONCLUSION In the mandibular first molars of EGFP-RhoA^DN transgenic mice, the enamel formation was disrupted and the adherens junctions of EGFP-RhoA^DN transgenic mice ameloblasts were implicated during amelogenesis. RhoA signaling pathway may play a critical role in enamel development by altering the adherens junctions in ameloblasts.
Adherens Junctions ; Ameloblasts ; Amelogenesis ; Animals ; Antigens, CD ; Cadherins/metabolism* ; Dental Enamel/metabolism* ; Enamel Organ ; Humans ; Mice ; Mice, Transgenic ; Molar ; Signal Transduction ; alpha Catenin ; beta Catenin ; rhoA GTP-Binding Protein/physiology*

OBJECTIVETo study the possible effect of antepartum taurine supplementation in regulating the activity of Rho family factors and promoting the proliferation of neural stem cells in neonatal rats with fetal growth restriction (FGR), and to provide a basis for antepartum taurine supplementation to promote brain development in children with FGR.

METHODSA total of 24 pregnant Sprague-Dawley rats were randomly divided into three groups: control, FGR, and taurine (n=8 each ). A rat model of FGR was established by food restriction throughout pregnancy. RT-PCR, immunohistochemistry, and Western blot were used to measure the expression of the specific intracellular markers for neural stem cells fatty acid binding protein 7 (FABP7), Rho-associated coiled-coil containing protein kinase 2 (ROCK2), ras homolog gene family, member A (RhoA), and Ras-related C3 botulinum toxin substrate (Rac).

RESULTSThe FGR group had significantly lower OD value of FABP7-positive cells and mRNA and protein expression of FABP7 than the control group, and the taurine group had significantly higher OD value of FABP7-positive cells and mRNA and protein expression of FABP7 than the FGR group (P<0.05). The FGR group had significantly higher mRNA expression of RhoA and ROCK2 than the control group. The taurine group had significantly higher mRNA expression of RhoA and ROCK2 than the control group and significantly lower expression than the FGR group (P<0.05). The FGR group had significantly lower mRNA expression of Rac than the control group. The taurine group had significantly higher mRNA expression of Rac than the FGR and control groups (P<0.05). The FGR group had significantly higher protein expression of RhoA and ROCK2 than the control group. The taurine group had significantly lower protein expression of RhoA and ROCK2 than the FGR group (P<0.05).

CONCLUSIONSAntepartum taurine supplementation can promote the proliferation of neural stem cells in rats with FGR, and its mechanism may be related to the regulation of the activity of Rho family factors.

Animals ; Animals, Newborn ; Body Weight ; drug effects ; Brain ; drug effects ; Cell Proliferation ; drug effects ; Fatty Acid-Binding Protein 7 ; analysis ; Female ; Fetal Growth Retardation ; drug therapy ; Male ; Neural Stem Cells ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley ; Taurine ; pharmacology ; rho-Associated Kinases ; analysis ; genetics ; rhoA GTP-Binding Protein ; analysis ; genetics

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

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

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

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

OBJECTIVE: To determine effects of the RhoA/Rho kinase signaling pathway on patients with pulmonary arterial hypertension related to chronic obstructive pulmonary diseases by testing levels of Rho-associated coiled-coil containing protein kinase 1(ROCK1) in peripheral blood monocytes in healthy subjects, patients with chronic obstructive pulmonary diseases (COPD), and patients with pulmonary arterial hypertension related to COPD. METHODS: Ten healthy subjects (Group A), 10 patients with COPD (Group B), and 10 patients with pulmonary arterial hypertension related to COPD (Group C) were enrolled, all of whom were hospitalized in the Third Hospital of Changsha between Dec. 2010 and Apr. 2011. Twenty milliliters of blood was collected from each subject. The peripheral blood mononuclear cells (PBMC) were separated by Percoll and, monocytes were incubated. Levels of ROCK1 in the three groups were measured by ELISA. The pulmonary function was measured by spirometric tests, and the pulmonary arterial systolic pressure (PASP) was detected by color Doppler echocardiogram. RESULTS: 1)The PASP in Group C was significantly higher than that of Groups A and B(P<0.01). 2) The levels of ROCK1 in monocytes of Group C were higher than those of Groups A and B(P<0.05). The levels of ROCK1 in monocytes of Group B were higher than those of Group A (P<0.05). 3) The levels of ROCK1 in monocytes of the three groups showed a positive correlation with PASP(r=0.661, P<0.05). 4) The levels of ROCK1 in monocytes of the three groups showed a negative correlation with forced expiratory volume at the first second/ forced vital capacity (FEV1%)(r=0.131, P>0.05). CONCLUSION Rho kinase plays a key role in the pathogenesis of pulmonary arterial hypertension. The ROCK1 may be a marker of the severity of pulmonary arterial hypertension related to COPD.
Aged ; Female ; Humans ; Hypertension, Pulmonary ; etiology ; metabolism ; physiopathology ; Leukocytes, Mononuclear ; metabolism ; Male ; Middle Aged ; Pulmonary Disease, Chronic Obstructive ; complications ; Signal Transduction ; physiology ; rho-Associated Kinases ; blood ; metabolism ; rhoA GTP-Binding Protein ; metabolism

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

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

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