This Article Abstract Full Text (PDF) All Versions of this Article: 37/8/2174    most recent 01.STR.0000231647.41578.dfv1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chrissobolis, S. Articles by Sobey, C. G. Search for Related Content PubMed PubMed Citation Articles by Chrissobolis, S. Articles by Sobey, C. G. Pubmed/NCBI databases Domain Related Collections Cerebrovascular disease/stroke Other diabetes Endothelium/vascular type/nitric oxide Other Vascular biology Brain Circulation and Metabolism

(Stroke. 2006;37:2174.)
© 2006 American Heart Association, Inc.

Comments, Opinions, and Reviews

Recent Evidence for an Involvement of Rho-Kinase in Cerebral Vascular Disease

Sophocles Chrissobolis, PhD Christopher G. Sobey, PhD

From the Department of Internal Medicine (S.C.), University of Iowa, Iowa City, and the Department of Pharmacology and Centre for Vascular Health Initiative (C.G.S.), Monash University, Clayton, Australia.

Correspondence to Christopher G. Sobey, PhD, Department of Pharmacology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia. E-mail chris.sobey{at}med.monash.edu.au

	Abstract

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
Background and Purpose— The small G protein rhoA and its downstream effector rho-kinase are both expressed in vascular cells and are involved in several cellular processes. One of these processes is the regulation of the phosphorylation state of myosin light chain in vascular muscle and thus, the development of force. Recently, considerable evidence for increased activity of this pathway in cerebral and noncerebral vessels has been reported in several cardiovascular diseases associated with increased vascular tone.

Summary of Review— The main aim of this brief review is to summarize current evidence for the involvement of rhoA/rho-kinase signaling in dysfunction of the cerebral circulation in disease states, such as cerebral vasospasm, hypertension, diabetes, and ischemic brain injury. We will also briefly consider the novel hypothesis that augmented activity of endothelial rho-kinase decreases nitric oxide production and contributes to increased vascular tone in disease and the possibility of this action being a key therapeutic target of statins (inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase) in cerebral and noncerebral arteries.

Conclusions— Considerable evidence indicates that rhoA/rho-kinase activity is commonly increased in cerebral vascular disease, not only in vascular muscle, but also in the endothelium and possibly in inflammatory cells and neurons.

Key Words: cerebral arteries • cerebrovascular disorders • endothelium • muscle, smooth • phospholipids • statins

	Introduction

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
Contractility of vascular muscle is governed by myosin light chain (MLC) phosphorylation. MLC is phosphorylated by Ca²⁺/calmodulin-dependent MLC-kinase and dephosphorylated by MLC phosphatase (MLCP). Modulation of MLC can thus occur independently of alterations in cytosolic Ca²⁺ concentration (Ca²⁺ sensitization) through signaling pathways that regulate MLCP activity, such as the rhoA- rho-kinase mechanism. When activated by rhoA, rho-kinase inhibits MLCP activity by phosphorylation of its (regulatory) myosin-binding subunit¹ (Figure 1). In both peripheral (for a review, see Somlyo and Somlyo²) and cerebral^3–10 circulations, rhoA/rho-kinase appears to be involved in the regulation of basal tone, as well as in mediating responses to vasoconstrictor agonists. The reader is also directed to several other reviews on the role of vascular rhoA/rho-kinase in cardiovascular diseases^2,11–19 and in the central nervous system (CNS).²⁰

View larger version (14K): [in this window] [in a new window]   Figure 1. Simplified schematic of regulation of rhoA/rho-kinase activity. In a vascular smooth muscle cell, rhoA is regulated by (1) guanine-nucleotide exchange factors (GEFs), which facilitate exchange of GDP for GTP, thus rendering rho active; (2) GTPase-activating proteins (GAPs), which accelerate intrinsic GTPase activity of rho, converting it back to its GDP-bound form and rendering rho inactive; and (3) GDP dissociation inhibitors (GDIs), which inhibit dissociation of GDP bound to rho, keeping rho inactive. After stimulation (eg, by agonist-receptor interaction, pressure, stretch, etc), GTP-bound rhoA activates rho-kinase, which phosphorylates the myosin-binding subunit of MLCP, thus inactivating it. Myosin light chain (MLC) phosphorylation is regulated by MLC kinase (MLCK, which phosphorylates and activates MLC) and MLC phosphatase (MLCP, which dephosphorylates and inhibits MLC). MLC phosphorylation leads to increased contractile tone via enhanced cross-bridging with actin.

	Rho G Proteins

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
The rho family of low-molecular-weight G proteins, which belongs to the Ras superfamily, can be divided into several different classes (for a review, see Aspenstrom²¹). The rho subfamily consists of 3 members: rhoA (which mediates known vascular effects and is expressed in cerebral vascular tissue^22–25), rhoB, and rhoC. Evidence for the involvement of rhoA in Ca²⁺ sensitization in permeabilized ovine cerebral arteries has been shown, wherein C3 exotoxin (a rho inactivator) inhibited GTPS-induced increases in tension.²⁶ RhoA is also expressed in noncerebral vascular tissue,^27,28 where it is involved in Ca²⁺ sensitization.² The activity of rhoA is regulated by 3 classes of enzymes: guanine-nucleotide exchange factors (GEFs), which facilitate the exchange of GDP for GTP, thus rendering rho active; GTPase-activating proteins (GAPs), which regulate inactivation of rho by accelerating intrinsic GTPase activity and converting rho back to its GDP-bound form; and GDP dissociation inhibitors (GDIs), which inhibit the dissociation of GDP bound to rho²¹ (Figure 1).

	Rho-Kinase

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
This ubiquitously expressed Ca²⁺-sensitizing effector of rho is a serine-threonine kinase, consisting of a rho-binding domain, and is activated by GTP-bound rhoA. Rho-kinase has 2 isoforms; ROK/ROCKII and ROKß/ROCKI,²⁹ with both isoforms expressed in cerebral vascular muscle.^22,25 Activated rho-kinase phosphorylates the myosin-binding (ie, regulatory) subunit of MLCP and thus inhibits myosin phosphatase activity.¹

	Methods Used to Study RhoA/Rho-Kinase

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
Pharmacological Inhibitors of RhoA/Rho-Kinase
Y-27632 and HA1077 (also known as fasudil) exhibit enhanced selectivity for rho-kinase over numerous other kinases,^30–33 eg, with IC₅₀ values for inhibition of ROCKII in the nanomolar and low micromolar range, respectively.³⁰ Both of these cell-permeable compounds inhibit rho-kinase by competing with ATP for binding.^31,32 Since the initial discoveries of Y-27632 and HA1077 as rho-kinase inhibitors, other inhibitors of this enzyme have been synthesized (discussed recently²⁰); however, in vascular studies, Y-27632 and fasudil are by far the most widely used. Although the inhibitor of rhoA, C3 exoenzyme, has also been used in vivo³⁴ and intact vessel preparations,³⁵ in its purified form C3 exoenzyme does not possess cell surface binding or translocation components; hence, it is often used in alternative approaches, such as cell membrane permeabilization, to introduce it into intact cells (discussed in Sah et al¹⁴).

Genetically Altered Mice, Dominant-Negative Mutants, and siRNA
Pharmacological inhibition of rho-kinase has been useful in establishing the role of the enzyme in blood vessels. However, such an approach has limitations, such as being unable to elucidate the rho-kinase isoform that mediates functional alterations in disease states. Very recently, ROCK1^+/– mice have been studied to specifically investigate the role of ROCK1 in cardiac fibrosis³⁶ and the downstream effects of hyperglycemia.³⁷ Such an approach will no doubt be useful to determine the importance of rho-kinase isoforms in cerebrovascular disease, eg, in experimentally induced models of hypertension.

Dominant-negative mutants have not yet been used to study rhoA/rho-kinase in cerebral vessels; however, such an approach has been used to study both rhoA^38,39 and rho-kinase^37,38 in cultured endothelial cells and intact peripheral arteries. These approaches, as well as the use of rhoA-specific small interfering (si) RNA,⁴⁰ will avoid the uncertainty of nonspecific effects associated with pharmacological inhibitors such as Y-27632 and HA1077.

	Involvement of RhoA/Rho-Kinase in Cerebral Myogenic Tone

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
Myogenic tone, an inherent property of smooth muscle, is characterized by pressure-induced vasoconstriction and is thus important for the development of basal vascular tone. RhoA/rho-kinase appears to be a major determinant of vascular smooth muscle contractility; hence, this pathway may contribute to the myogenic response. Consistent with this, rhoA in vascular smooth muscle can be strongly activated by stretch.⁴¹ Pressure-induced constriction of the middle cerebral artery is inhibited by Y-27632,⁴² and Y-27632 relaxes posterior cerebral artery segments after pressure-induced constriction,⁴³ implicating rho-kinase in the cerebral myogenic response. Another study suggested rho-kinase to be important in maintaining basal tone of the posterior cerebral artery, whereas it may have played a minimal role in pressure-induced constriction.⁴⁴ In vivo, Y-27632 causes concentration-dependent dilatation of cerebral arteries^3,22,45–47 and arterioles.⁴⁸ Such findings generally implicate the rhoA/rho-kinase pathway as a signaling mechanism of major importance underlying the myogenic response, and hence, basal vascular tone in the cerebral circulation.

Interestingly, a lower rho-kinase function in cerebral arteries of females compared with males²² is consistent with the lower myogenic tone in female compared with male cerebral arteries.⁴⁹ Lower rho-kinase function in the cerebral vessels of females appears to be dependent on endogenous estrogen,²² which inhibits rho-kinase expression in cultured vascular cells,⁵⁰ and this effect appears unrelated to nitric oxide (NO) synthase activity.²² Estrogen may suppress rho-kinase activity via activation of Rnd1⁵¹ and consequently, GAP, leading to decreased levels of GTP-bound rhoA, rho-kinase activity, and contractile tone.

	Vascular Disease States

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
Cerebral Vasospasm
Increased contractility of vascular muscle, which may, at least in part, be the result of increased rhoA/rho-kinase activity, is now thought to contribute to the severe arterial narrowing observed in cerebral vasospasm after subarachnoid hemorrhage (SAH).⁵² After SAH, rho-kinase activity in the basilar artery is increased.⁵³ Phosphorylation of myosin binding subunit (MBS; thus decreasing MLCP activity) and MLC are also increased after SAH, and they can be decreased acutely by treatment with Y-27632.⁵³ Importantly, Y-27632 prevented narrowing of the basilar artery after SAH,⁵⁴ thereby providing functional evidence for increased rho-kinase activity after SAH. Intravenous injection of HA1077 also inhibits constriction of the basilar artery after SAH.⁵⁵ Furthermore, mRNA expression of both rhoA and rho-kinase is reported to be increased in the basilar artery after SAH.²⁵

Oxyhemoglobin is a proposed mediator of cerebral vasospasm, and the prolonged cerebral artery constriction elicited by oxyhemoglobin is even more pronounced after SAH, a mechanism that involves rhoA/rho-kinase activation.⁵⁶ Y-27632 and HA1077 both inhibit oxyhemoglobin-induced constriction of the rabbit basilar artery, and oxyhemoglobin-induced translocation of rho to the membrane is blocked by an inhibitor of rho prenylation.⁵⁶ Endothelin-1, also implicated as a mediator of cerebral vasospasm, potentiates both rhoA translocation and vasoconstriction by oxyhemoglobin, at least the latter effect being inhibited by Y-27632 and HA1077.⁵⁷ Furthermore, Y-27632 reversed constriction by endothelin-1 and prevented Ca²⁺ sensitization induced by endothelin-1,⁵⁸ consistent with the possibility that endothelin-1 contributes to cerebral vasospasm via rhoA/rho-kinase activation. Lysophospholipids, such as sphingosine-1-phosphate and sphingosylphosphorylcholine, have also been implicated in the pathogenesis of cerebral vasospasm and constrict cerebral arteries by activating rho-kinase.^7,8

Fasudil is now used clinically in Japan for the treatment of cerebral vasospasm after SAH,¹⁶ and although fasudil has beneficial effects, it has not eliminated vasospasm development. After oral absorption, fasudil is metabolized to hydroxyfasudil, a more selective rho-kinase inhibitor than fasudil,⁵⁹ and this may actually be the active compound. Thus, although it seems unlikely that any single spasmogen contributes solely to cerebral vasospasm after SAH, the recognition that several major candidates indeed elicit vasoconstriction by increasing rhoA/rho-kinase activity and that a rho-kinase inhibitor has benefit in the clinical context provide good evidence that activation of this pathway is involved (Figure 2).

View larger version (18K): [in this window] [in a new window]   Figure 2. Diseases of the cerebral circulation associated with increased rhoA/rho-kinase activity include post-SAH cerebral vasospasm, hypertension, and diabetes. Aging is also associated with increased vascular rhoA activity. Several receptor agonists that cause vasoconstriction and that have been proposed to contribute to development of cerebral vasospasm, have been shown to increase vascular rhoA/rho-kinase activity.

Chronic Hypertension
A disease in which myogenic tone of cerebral arteries is enhanced, chronic hypertension is associated with changes in both vascular function (eg, impaired NO production attributable to endothelial dysfunction) and structure (eg, hypertrophy, which contributes to thickening of the vessel wall and reduction in lumen size). To our knowledge, no study has addressed whether rhoA/rho-kinase contributes to the altered structure of cerebral vessels in hypertension. Few studies have addressed whether rhoA/rho-kinase function is increased in the cerebral circulation during hypertension. Enhanced dilator responses of the basilar artery to Y-27632 in vivo in both genetic and pharmacological models of chronic hypertension³ suggest an increase in cerebral artery rho-kinase function in hypertension (Figure 2). Similarly, pressure-dependent development of myogenic tone of the posterior cerebral artery is inhibited by Y-27632 to a greater extent in spontaneously hypertensive (SHR) versus Wistar-Kyoto rats (WKY).⁴⁴ These findings suggest an important role for rho-kinase in increased myogenic tone of cerebral arteries during hypertension and are supported by others reporting greater responses to Y-27632 in the basilar artery of SHR versus WKY.^46,47 Complementary molecular evidence showing increased rhoA/rho-kinase expression is yet to be reported in the cerebral circulation, but it has been demonstrated in various models of hypertension in other vascular beds.^27,28,60

As well as inhibiting MLCP activity, rhoA activation can induce actin polymerization,⁶¹ a process that is involved in the myogenic response.^43,62 Thus, increased rhoA activity in hypertension resulting in increased myogenic tone may occur as a result of inhibition of MLCP activity and/or activation of actin polymerization. The contribution of actin polymerization to remodeling⁶³ of smooth muscle may be important in rhoA-induced structural alterations in cerebral vessels in hypertension, although this is yet to be investigated.

Regarding the important question of cause and effect, it remains to be clarified whether increased vascular rho-kinase activity can be a cause of hypertension or whether rho-kinase activity is increased only as a consequence of hypertension. Clearly, rho-kinase activity seems to increase in cerebral and noncerebral vessels after induction of experimental hypertension.^3,27,28,33 Furthermore, in the aorta from several models of genetic and pharmacologically induced hypertension, GTP-bound rhoA is increased relative to that in normotensive controls, although rhoA, ROK, and ROKß total expression is unaltered.²⁸ On the other hand, rhoA expression is increased in the aorta from SHR relative to WKY at 4 weeks of age, ie, before development of hypertension in SHR.²⁷ Similarly, hydroxyfasudil (an active metabolite of fasudil) inhibits agonist-induced mesenteric vasoconstriction in 4-week-old SHR but not WKY⁶⁰; both findings together probably indicate that the increased activity and expression of vascular rhoA/rho-kinase can also be independent of or precede the development of genetic hypertension.

Diabetes and Aging
A few studies have investigated whether diabetes is associated with increased cerebral vascular rhoA/rho-kinase activity. In the basilar artery from streptozotocin-injected (ie, type 1 diabetic) rats, levels of rhoA mRNA and membrane-bound rhoA protein were found to be greater than in controls.²⁴ Functional data showing enhanced dilator responses to Y-27632 in cerebral arterioles of type 2 diabetic compared with control mice⁴⁸ also suggest that rhoA/rho-kinase activity is increased in diabetes (Figure 2). By contrast, dilator responses of the basilar artery in vivo to Y-27632 were similar in Zucker lean and Zucker obese rats, suggesting that rho-kinase activity is unaffected by insulin resistance,⁴⁵ which is a characteristic of type 2 diabetes. Thus, whether or not rhoA/rho-kinase activity is altered may be dependent on the pathologies produced by different diabetic models.

In the adult rat basilar artery, rhoA mRNA expression and membrane-bound rhoA protein have been reported to increase with age, from 2 to 19 months of age, with these increases occurring both in endothelial and smooth muscle layers.²³ Thus, given the evidence that endothelial rho-kinase activity can attenuate NO generation by endothelial NOS and thus increase smooth muscle contractility^64–66 (see following section) and that dilator responses of cerebral vessels to endothelium-dependent agonists are impaired with aging,⁶⁷ enhanced endothelial rhoA/rho-kinase activity could perhaps contribute to the endothelial dysfunction in aging (Figures 2 and 3).

View larger version (20K): [in this window] [in a new window]   Figure 3. Recent findings suggest that endothelial rho-kinase may inhibit eNOS function. Statin-induced inhibition of endothelial rhoA activity may increase eNOS activity and enhance NO bioavailability. Thus, it is proposed that excessive arterial contraction in vascular disease may in part be attributable to impaired endothelial function from higher activity of rhoA/rho-kinase in the endothelium, as well as the well established upregulation of these proteins in vascular smooth muscle. Because statins can inhibit rhoA activation, both the endothelial and smooth muscle rhoA/rho-kinase pathways could represent important targets of statin therapy.

Brain Ischemic Injury and Inflammation
Because rho-kinase is ubiquitously expressed, it is conceivable that activation of this pathway in nonvascular cells also indirectly contributes to brain injury associated with cerebral vascular disease. For example, fasudil was shown to protect against neuronal cell death in the gerbil brain after bilateral occlusion of the common carotid arteries.⁶⁸ Beneficial actions of rho/rho-kinase inhibition in neurons after brain injury likely involve promotion of neurite outgrowth, because rho activity prevents neurite initiation and induces neurite retraction, with mechanism(s) involving several rho proteins and rho-kinase substrates in neurons, including MLCP (discussed in Govek et al⁶⁹). In various rat models of stroke, fasudil and hydroxyfasudil improve blood flow to ischemic brain regions, improve neurological function, decrease infarct volume, prevent neutrophil accumulation, and protect against ischemia-induced neuronal cell loss.^70–72 Neutrophil accumulation may be detrimental to the ischemic brain by adhering to endothelial cells or releasing pathological mediators such as proteases or superoxide anion. Indeed, involvement of rho/rho-kinase in controlling the migration of human neutrophils likely involves phosphorylation of MLC in neutrophils⁷³ and may⁷⁴ or may not⁷⁵ involve actin polymerization also. In a model of middle cerebral artery occlusion, mice treated with the rho inhibitor, C3 exotoxin, had smaller cerebral infarcts.³⁴ Thus, in ischemic brain injury, the target site(s) of the beneficial effect of rhoA/rho-kinase inhibition may be in vascular and/or nonvascular cells. However, it is interesting to note that a recent clinical study reported rho-kinase activity in polymorphonuclear leukocytes to be increased in patients after acute ischemic stroke.⁷⁶ Thus, a new concept is that rhoA/rho-kinase activity, in invading inflammatory cells or even neurons, may also contribute to ischemic brain injury.

Cerebral endothelial cells and their tight linking junctions compose the blood-brain barrier (BBB), which limits access of blood-borne molecules into the brain. RhoA/rho-kinase signaling may be a key mechanism in altered BBB permeability in response to stimuli such as monocyte chemoattractant protein-1, which in cultured mouse brain endothelial cells induced functional, morphological, and biochemical changes in endothelial permeability, effects that were prevented by C3 exoenzyme, Y-27632, or a rho-dominant negative mutant.⁷⁷ Furthermore, stimuli such as protease-activated receptor-1 activators may enter the brain as a result of increased BBB permeability and induce astrogliosis via activation of rho-kinase.⁷⁸ Because astrogliosis is a feature of acute and chronic neurodegenerative diseases that are characterized by an inflammatory component, rhoA/rho-kinase may contribute to brain inflammation after breakdown of the BBB in disorders of the CNS. However, an emerging hypothesis concerns the importance of actin polymerization in modulating BBB permeability.⁷⁹ Because rhoA may stimulate actin polymerization, it is conceivable that rhoA activity is important in maintaining the structural integrity of the BBB. Clearly, the role of rhoA/rho-kinase regarding effects on BBB permeability requires further investigation, although it may modulate or contribute to BBB permeability.

	Endothelium, RhoA/Rho-Kinase, and Statins

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
To date, the contribution of rhoA/rho-kinase to the control of vascular tone has mostly been considered with respect to increased signaling activity in vascular muscle. However, recent studies (so far, mostly in noncerebral vessels) suggest that augmented activity of the rhoA/rho-kinase signaling pathway in endothelial cells may also contribute to the enhanced vascular contractility observed during disease. In the endothelium, phosphatidylinositol 3-kinase (PI3K) activates the protein kinase Akt, which phosphorylates and activates endothelial NOS, resulting in NO production.⁸⁰ In cultured endothelial cells, rho-kinase inhibition is reported to increase Akt phosphorylation and nitrite (a stable product of NO) production, an effect blocked by PI3K inhibition.⁸¹ Those findings are in support of functional data that phenylephrine-induced vasoconstriction is inhibited by Y-27632⁶⁴ or a rhoA-binding fragment of rho-kinase⁶⁶ in an endothelium-, PI3K-, and NOS-dependent manner. Hence, endothelial rho-kinase may normally inhibit NO production via PI3K inhibition even in healthy arteries, but this effect could conceivably be exacerbated in disease states⁶⁴ (Figure 3). Moreover, in humans, increases in forearm blood flow in response to acetylcholine, which are impaired in cigarette smokers, are improved by fasudil treatment, consistent with a clinical link between increased rho-kinase activity and endothelial dysfunction.⁸² Thus, endothelial and smooth muscle cell rhoA/rhoA-kinase appears to exert procontractile effects through distinct mechanisms. It remains to be determined whether rhoA/rho-kinase-mediated inhibition of endothelial NO production is important in the cerebral circulation, where NO is a major modulator of vascular tone,⁶⁷ or indeed whether expression or activity of cerebral endothelial rhoA/rho-kinase is increased during cardiovascular disease.

The beneficial cardiovascular effects of statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are now well known to extend beyond their cholesterol-lowering activity. For example, in noncerebral vessels, statins can modulate constrictor responses of endothelium-denuded and especially of endothelium-intact vessels without lowering plasma cholesterol,⁸³ they possess antihypertensive effects, and they improve endothelium-dependent vascular relaxation.⁸⁴ In blocking cholesterol biosynthesis, statins also prevent formation of isoprenoid intermediates, including geranylgeranyl pyrophosphate, required for the geranylgeranylation of rhoA. Importantly, the isoprenylation of rho is a prerequisite for rho activation, facilitating its interaction with the plasma membrane where GDP-GTP exchange is thought to occur. By preventing this membrane interaction, statins inactivate rhoA, leading to increased endothelial Akt phosphorylation,⁸⁵ endothelial NOS expression and activity, and increased endothelial NO production.^17,64 Interestingly, reduction of cerebral infarct volume (after middle cerebral artery occlusion) by simvastatin is endothelial NOS-dependent in normocholesterolemic mice, suggesting that statins may exert protective effects in stroke through such a mechanism.³⁴ Thus, in addition to inhibiting smooth muscle rhoA/rho-kinase, the beneficial effects of statins could include inhibition of endothelial rhoA/rho-kinase and thus, increased activity of PI3K/Akt and endothelial NOS, an effect likely to offer protection after cerebral ischemia (Figure 3).

	Conclusions

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 
Increasing evidence indicates that cerebral vascular rhoA/rho-kinase activity is augmented in several disease states. Thus far, most attention has focused on rhoA/rho-kinase signaling in vascular muscle. However, a new concept is that increased endothelial rhoA/rho-kinase activity may also contribute to exaggerated vasoconstriction during hypertension, diabetes, and aging, all of which are strongly associated with endothelial dysfunction in the cerebral circulation. Furthermore, it is possible that rhoA/rho-kinase activity in invading inflammatory cells, or even neurons, contributes to ischemic brain injury.

	Acknowledgments

 
We are grateful to Frank Faraci for critical evaluation of this manuscript.

Sources of Funding

C.G.S. is supported by a senior research fellowship from the National Health and Medical Research Council of Australia (NHMRC; ID 350327). S.C. is supported by a C.J. Martin Training Fellowship from the NHMRC (ID 359282).

Disclosures

None.

Received March 6, 2006; revision received April 14, 2006; accepted May 10, 2006.

	References

Top Abstract Introduction Rho G Proteins Rho-Kinase Methods Used to Study... Involvement of RhoA/Rho-Kinase... Vascular Disease States Endothelium, RhoA/Rho-Kinase,... Conclusions References

 

1. Kimura K, Ito M, Amano M, Chihara K, Fukata Y, Nakafuku M, Yamamori B, Feng J, Nakano T, Okawa K, Iwamatsu A, Kaibuchi K. Regulation of myosin phosphatase by rho and rho-associated kinase (rho-kinase). Science. 1996; 273: 245–248.[Abstract]
2. Somlyo AP, Somlyo AV. Ca²⁺ sensitivity of smooth muscle and nonmuscle myosin, II: modulated by G proteins, kinases, and myosin phosphatase. Physiol Rev. 2003; 83: 1325–1358.[Abstract/Free Full Text]
3. Chrissobolis S, Sobey CG. Evidence that rho-kinase activity contributes to cerebral vascular tone in vivo and is enhanced during chronic hypertension: comparison with protein kinase C. Circ Res. 2001; 88: 774–779.[Abstract/Free Full Text]
4. Luykenaar KD, Brett SE, Wu BN, Wiehler WB, Welsh DG. Pyrimidine nucleotides suppress KDR currents and depolarize rat cerebral arteries by activating rho kinase. Am J Physiol Heart Circ Physiol. 2004; 286: H1088–H1100.[Abstract/Free Full Text]
5. Nakamura K, Nishimura J, Hirano K, Ibayashi S, Fujishima M, Kanaide H. Hydroxyfasudil, an active metabolite of fasudil hydrochloride, relaxes the rabbit basilar artery by disinhibition of myosin light chain phosphatase. J Cereb Blood Flow Metab. 2001; 21: 876–885.[CrossRef][Medline] [Order article via Infotrieve]
6. Salomone S, Yoshimura S, Reuter U, Foley M, Thomas SS, Moskowitz MA, Waeber C. S1p3 receptors mediate the potent constriction of cerebral arteries by sphingosine-1-phosphate. Eur J Pharmacol. 2003; 469: 125–134.[CrossRef][Medline] [Order article via Infotrieve]
7. Shirao S, Kashiwagi S, Sato M, Miwa S, Nakao F, Kurokawa T, Todoroki-Ikeda N, Mogami K, Mizukami Y, Kuriyama S, Haze K, Suzuki M, Kobayashi S. Sphingosylphosphorylcholine is a novel messenger for rho-kinase-mediated Ca²⁺ sensitization in the bovine cerebral artery: unimportant role for protein kinase C. Circ Res. 2002; 91: 112–119.[Abstract/Free Full Text]
8. Tosaka M, Okajima F, Hashiba Y, Saito N, Nagano T, Watanabe T, Kimura T, Sasaki T. Sphingosine 1-phosphate contracts canine basilar arteries in vitro and in vivo: possible role in pathogenesis of cerebral vasospasm. Stroke. 2001; 32: 2913–2919.[Abstract/Free Full Text]
9. Faraci FM, Lamping KG, Modrick ML, Ryan MJ, Sigmund CD, Didion SP. Cerebral vascular effects of angiotensin II: new insights from genetic models. J Cereb Blood Flow Metab. 2006; 26: 449–455.[CrossRef][Medline] [Order article via Infotrieve]
10. Watanabe Y, Faraci FM, Heistad DD. Activation of rho-associated kinase during augmented contraction of the basilar artery to serotonin after subarachnoid hemorrhage. Am J Physiol Heart Circ Physiol. 2005; 288: H2653–H2658.[Abstract/Free Full Text]
11. Hu E, Lee D. Rho kinase inhibitors as potential therapeutic agents for cardiovascular diseases. Curr Opin Investig Drugs. 2003; 4: 1065–1075.[Medline] [Order article via Infotrieve]
12. Pacaud P, Sauzeau V, Loirand G. Rho proteins and vascular diseases. Arch Mal Coeur Vaiss. 2005; 98: 249–254.[Medline] [Order article via Infotrieve]
13. Rikitake Y, Liao JK. ROCKS as therapeutic targets in cardiovascular diseases. Expert Rev Cardiovasc Ther. 2005; 3: 441–451.[CrossRef][Medline] [Order article via Infotrieve]
14. Sah VP, Seasholtz TM, Sagi SA, Brown JH. The role of rho in G protein-coupled receptor signal transduction. Annu Rev Pharmacol Toxicol. 2000; 40: 459–489.[CrossRef][Medline] [Order article via Infotrieve]
15. Shimokawa H, Takeshita A. Rho-kinase is an important therapeutic target in cardiovascular medicine. Arterioscler Thromb Vasc Biol. 2005; 25: 1767–1775.[Abstract/Free Full Text]
16. Hirooka Y, Shimokawa H. Therapeutic potential of rho-kinase inhibitors in cardiovascular diseases. Am J Cardiovasc Drugs. 2005; 5: 31–39.[CrossRef][Medline] [Order article via Infotrieve]
17. Budzyn K, Marley PD, Sobey CG. Targeting rho and rho-kinase in the treatment of cardiovascular disease. Trends Pharmacol Sci. 2006; 27: 97–104.[CrossRef][Medline] [Order article via Infotrieve]
18. Loirand G, Guerin P, Pacaud P. Rho kinases in cardiovascular physiology and pathophysiology. Circ Res. 2006; 98: 322–334.[Abstract/Free Full Text]
19. Noma K, Oyama N, Liao JK. Physiological role of ROCKS in the cardiovascular system. Am J Physiol Cell Physiol. 2006; 290: C661–C668.[Abstract/Free Full Text]
20. Mueller BK, Mack H, Teusch N. Rho kinase, a promising drug target for neurological disorders. Nat Rev Drug Discov. 2005; 4: 387–398.[CrossRef][Medline] [Order article via Infotrieve]
21. Aspenstrom P. Effectors for the rho GTPases. Curr Opin Cell Biol. 1999; 11: 95–102.[CrossRef][Medline] [Order article via Infotrieve]
22. Chrissobolis S, Budzyn K, Marley PD, Sobey CG. Evidence that estrogen suppresses rho-kinase function in the cerebral circulation in vivo. Stroke. 2004; 35: 2200–2205.[Abstract/Free Full Text]
23. Miao L, Calvert JW, Tang J, Parent AD, Zhang JH. Age-related rhoA expression in blood vessels of rats. Mech Ageing Dev. 2001; 122: 1757–1770.[CrossRef][Medline] [Order article via Infotrieve]
24. Miao L, Calvert JW, Tang J, Zhang JH. Upregulation of small GTPase rhoA in the basilar artery from diabetic (mellitus) rats. Life Sci. 2002; 71: 1175–1185.[CrossRef][Medline] [Order article via Infotrieve]
25. Miyagi Y, Carpenter RC, Meguro T, Parent AD, Zhang JH. Upregulation of rho A and rho kinase messenger RNAs in the basilar artery of a rat model of subarachnoid hemorrhage. J Neurosurg. 2000; 93: 471–476.[Medline] [Order article via Infotrieve]
26. Akopov SE, Zhang L, Pearce WJ. Regulation of Ca²⁺ sensitization by PKC and rho proteins in ovine cerebral arteries: effects of artery size and age. Am J Physiol Heart Circ Physiol. 1998; 275: H930–H939.[Abstract/Free Full Text]
27. Seasholtz TM, Zhang T, Morissette MR, Howes AL, Yang AH, Brown JH. Increased expression and activity of rhoA are associated with increased DNA synthesis and reduced p27(KIP1) expression in the vasculature of hypertensive rats. Circ Res. 2001; 89: 488–495.[Abstract/Free Full Text]
28. Seko T, Ito M, Kureishi Y, Okamoto R, Moriki N, Onishi K, Isaka N, Hartshorne DJ, Nakano T. Activation of rhoA and inhibition of myosin phosphatase as important components in hypertension in vascular smooth muscle. Circ Res. 2003; 92: 411–418.[Abstract/Free Full Text]
29. Leung T, Chen XQ, Manser E, Lim L. The p160 rhoA-binding kinase ROK- is a member of a kinase family and is involved in the reorganization of the cytoskeleton. Mol Cell Biol. 1996; 16: 5313–5327.[Abstract]
30. Davies SP, Reddy H, Caivano M, Cohen P. Specificity and mechanism of action of some commonly used protein kinase inhibitors. Biochem J. 2000; 351: 95–105.[CrossRef][Medline] [Order article via Infotrieve]
31. Ishizaki T, Uehata M, Tamechika I, Keel J, Nonomura K, Maekawa M, Narumiya S. Pharmacological properties of Y-27632, a specific inhibitor of rho-associated kinases. Mol Pharmacol. 2000; 57: 976–983.[Abstract/Free Full Text]
32. Sasaki Y, Suzuki M, Hidaka H. The novel and specific rho-kinase inhibitor (S)-(+)-2-methyl-1-[(4-methyl-5-isoquinoline)sulfonyl]-homopiperazine as a probing molecule for rho-kinase-involved pathway. Pharmacol Ther. 2002; 93: 225–232.[CrossRef][Medline] [Order article via Infotrieve]
33. Uehata M, Ishizaki T, Satoh H, Ono T, Kawahara T, Morishita T, Tamakawa H, Yamagami K, Inui J, Maekawa M, Narumiya S. Calcium sensitization of smooth muscle mediated by a rho-associated protein kinase in hypertension [see comments]. Nature. 1997; 389: 990–994.[CrossRef][Medline] [Order article via Infotrieve]
34. Laufs U, Endres M, Stagliano N, Amin-Hanjani S, Chui DS, Yang SX, Simoncini T, Yamada M, Rabkin E, Allen PG, Huang PL, Bohm M, Schoen FJ, Moskowitz MA, Liao JK. Neuroprotection mediated by changes in the endothelial actin cytoskeleton. J Clin Invest. 2000; 106: 15–24.[Medline] [Order article via Infotrieve]
35. Nishikawa Y, Doi M, Koji T, Watanabe M, Kimura S, Kawasaki S, Ogawa A, Sasaki K. The role of rho and rho-dependent kinase in serotonin-induced contraction observed in bovine middle cerebral artery. Tohoku J Exp Med. 2003; 201: 239–249.[CrossRef][Medline] [Order article via Infotrieve]
36. Rikitake Y, Oyama N, Wang CY, Noma K, Satoh M, Kim HH, Liao JK. Decreased perivascular fibrosis but not cardiac hypertrophy in ROCK1+/– haploinsufficient mice. Circulation. 2005; 112: 2959–2965.[Abstract/Free Full Text]
37. Rikitake Y, Liao JK. Rho-kinase mediates hyperglycemia-induced plasminogen activator inhibitor-1 expression in vascular endothelial cells. Circulation. 2005; 111: 3261–3268.[Abstract/Free Full Text]
38. Bolz SS, Vogel L, Sollinger D, Derwand R, Boer C, Pitson SM, Spiegel S, Pohl U. Sphingosine kinase modulates microvascular tone and myogenic responses through activation of rhoA/rho kinase. Circulation. 2003; 108: 342–347.[Abstract/Free Full Text]
39. Bolz SS, Vogel L, Sollinger D, Derwand R, de Wit C, Loirand G, Pohl U. Nitric oxide-induced decrease in calcium sensitivity of resistance arteries is attributable to activation of the myosin light chain phosphatase and antagonized by the rhoA/rho kinase pathway. Circulation. 2003; 107: 3081–3087.[Abstract/Free Full Text]
40. Profirovic J, Gorovoy M, Niu J, Pavlovic S, Voyno-Yasenetskaya T. A novel mechanism of G protein-dependent phosphorylation of vasodilator-stimulated phosphoprotein. J Biol Chem. 2005; 280: 32866–32876.[Abstract/Free Full Text]
41. Numaguchi K, Eguchi S, Yamakawa T, Motley ED, Inagami T. Mechanotransduction of rat aortic vascular smooth muscle cells requires rhoA and intact actin filaments. Circ Res. 1999; 85: 5–11.[Abstract/Free Full Text]
42. Lagaud G, Gaudreault N, Moore ED, Van Breemen C, Laher I. Pressure-dependent myogenic constriction of cerebral arteries occurs independently of voltage-dependent activation. Am J Physiol Heart Circ Physiol. 2002; 283: H2187–H2195.[Abstract/Free Full Text]
43. Gokina NI, Park KM, McElroy-Yaggy K, Osol G. Effects of rho kinase inhibition on cerebral artery myogenic tone and reactivity. J Appl Physiol. 2005; 98: 1940–1948.[Abstract/Free Full Text]
44. Jarajapu YP, Knot HJ. Relative contribution of rho-kinase and PKC to myogenic tone in rat cerebral arteries in hypertension. Am J Physiol Heart Circ Physiol. 2005; 289: H1917–H1922.[Abstract/Free Full Text]
45. Erdos B, Snipes JA, Kis B, Miller AW, Busija DW. Vasoconstrictor mechanisms in the cerebral circulation are unaffected by insulin resistance. Am J Physiol Regul Integr Comp Physiol. 2004; 287: R1456–R1461.[Abstract/Free Full Text]
46. Kitayama J, Kitazono T, Ooboshi H, Takada J, Fujishima M, Ibayashi S. Long-term effects of benidipine on cerebral vasoreactivity in hypertensive rats. Eur J Pharmacol. 2002; 438: 153–158.[CrossRef][Medline] [Order article via Infotrieve]
47. Kitazono T, Ago T, Kamouchi M, Santa N, Ooboshi H, Fujishima M, Ibayashi S. Increased activity of calcium channels and rho-associated kinase in the basilar artery during chronic hypertension in vivo. J Hypertens. 2002; 20: 879–884.[CrossRef][Medline] [Order article via Infotrieve]
48. Didion SP, Lynch CM, Baumbach GL, Faraci FM. Impaired endothelium-dependent responses and enhanced influence of rho-kinase in cerebral arterioles in type II diabetes. Stroke. 2005; 36: 342–347.[Abstract/Free Full Text]
49. Geary GG, Krause DN, Duckles SP. Estrogen reduces myogenic tone through a nitric oxide-dependent mechanism in rat cerebral arteries. Am J Physiol. 1998; 275: H292–H300.[Medline] [Order article via Infotrieve]
50. Hiroki J, Shimokawa H, Mukai Y, Ichiki T, Takeshita A. Divergent effects of estrogen and nicotine on rho-kinase expression in human coronary vascular smooth muscle cells. Biochem Biophys Res Commun. 2005; 326: 154–159.[CrossRef][Medline] [Order article via Infotrieve]
51. Solaro RJ. Myosin light chain phosphatase: a Cinderella of cellular signaling. Circ Res. 2000; 87: 173–175.[Free Full Text]
52. Pluta RM. Delayed cerebral vasospasm and nitric oxide: review, new hypothesis, and proposed treatment. Pharmacol Ther. 2005; 105: 23–56.[CrossRef][Medline] [Order article via Infotrieve]
53. Sato M, Tani E, Fujikawa H, Kaibuchi K. Involvement of rho-kinase-mediated phosphorylation of myosin light chain in enhancement of cerebral vasospasm. Circ Res. 2000; 87: 195–200.[Abstract/Free Full Text]
54. Obara K, Nishizawa S, Koide M, Nozawa K, Mitate A, Ishikawa T, Nakayama K. Interactive role of protein kinase C- with rho-kinase in the development of cerebral vasospasm in a canine two-hemorrhage model. J Vasc Res. 2005; 42: 67–76.[CrossRef][Medline] [Order article via Infotrieve]
55. Kim I, Leinweber BD, Morgalla M, Butler WE, Seto M, Sasaki Y, Peterson JW, Morgan KG. Thin and thick filament regulation of contractility in experimental cerebral vasospasm. Neurosurgery. 2000; 46: 440–447.[Medline] [Order article via Infotrieve]
56. Wickman G, Lan C, Vollrath B. Functional roles of the rho/rho kinase pathway and protein kinase C in the regulation of cerebrovascular constriction mediated by hemoglobin: relevance to subarachnoid hemorrhage and vasospasm. Circ Res. 2003; 92: 809–816.[Abstract/Free Full Text]
57. Lan C, Das D, Wloskowicz A, Vollrath B. Endothelin-1 modulates hemoglobin-mediated signaling in cerebrovascular smooth muscle via rhoa/rho kinase and protein kinase C. Am J Physiol Heart Circ Physiol. 2004; 286: H165–H173.[Abstract/Free Full Text]
58. Scherer EQ, Herzog M, Wangemann P. Endothelin-1-induced vasospasms of spiral modiolar artery are mediated by rho-kinase-induced Ca²⁺ sensitization of contractile apparatus and reversed by calcitonin gene-related peptide. Stroke. 2002; 33: 2965–2971.[Abstract/Free Full Text]
59. Shimokawa H, Seto M, Katsumata N, Amano M, Kozai T, Yamawaki T, Kuwata K, Kandabashi T, Egashira K, Ikegaki I, Asano T, Kaibuchi K, Takeshita A. Rho-kinase-mediated pathway induces enhanced myosin light chain phosphorylations in a swine model of coronary artery spasm. Cardiovasc Res. 1999; 43: 1029–1039.[Abstract/Free Full Text]
60. Mukai Y, Shimokawa H, Matoba T, Kandabashi T, Satoh S, Hiroki J, Kaibuchi K, Takeshita A. Involvement of rho-kinase in hypertensive vascular disease: a novel therapeutic target in hypertension. FASEB J. 2001; 15: 1062–1064.[Free Full Text]
61. Ridley AJ, Hall A. The small GTP-binding protein rho regulates the assembly of focal adhesions and actin stress fibers in response to growth factors. Cell. 1992; 70: 389–399.[CrossRef][Medline] [Order article via Infotrieve]
62. Cipolla MJ, Gokina NI, Osol G. Pressure-induced actin polymerization in vascular smooth muscle as a mechanism underlying myogenic behavior. FASEB J. 2002; 16: 72–76.[Abstract/Free Full Text]
63. Wang J, Zohar R, McCulloch CA. Multiple roles of -smooth muscle actin in mechanotransduction. Exp Cell Res. 2006; 312: 205–214.[Medline] [Order article via Infotrieve]
64. Budzyn K, Marley PD, Sobey CG. Opposing roles of endothelial and smooth muscle phosphatidylinositol 3-kinase in vasoconstriction: effects of rho-kinase and hypertension. J Pharmacol Exp Ther. 2005; 313: 1248–1253.[Abstract/Free Full Text]
65. Rikitake Y, Liao JK. Rho GTPases, statins, and nitric oxide. Circ Res. 2005; 97: 1232–1235.[Abstract/Free Full Text]
66. Shiga N, Hirano K, Hirano M, Nishimura J, Nawata H, Kanaide H. Long-term inhibition of rhoA attenuates vascular contractility by enhancing endothelial no production in an intact rabbit mesenteric artery. Circ Res. 2005; 96: 1014–1021.[Abstract/Free Full Text]
67. Faraci FM, Heistad DD. Regulation of the cerebral circulation: role of endothelium and potassium channels. Physiol Rev. 1998; 78: 53–97.[Abstract/Free Full Text]
68. Asano T, Ikegaki I, Satoh S, Mochizuki D, Hidaka H, Suzuki Y, Shibuya M, Sugita K. Blockade of intracellular actions of calcium may protect against ischaemic damage to the gerbil brain. Br J Pharmacol. 1991; 103: 1935–1938.[Medline] [Order article via Infotrieve]
69. Govek EE, Newey SE, Van Aelst L. The role of the rho GTPases in neuronal development. Genes Dev. 2005; 19: 1–49.[Abstract/Free Full Text]
70. Ohtaki M, Tranmer B. Pretreatment of transient focal cerebral ischemia in rats with the calcium antagonist AT877. Stroke. 1994; 25: 1234–1240.[Abstract]
71. Satoh S, Kobayashi T, Hitomi A, Ikegaki I, Suzuki Y, Shibuya M, Yoshida J, Asano T. Inhibition of neutrophil migration by a protein kinase inhibitor for the treatment of ischemic brain infarction. Jpn J Pharmacol. 1999; 80: 41–48.[CrossRef][Medline] [Order article via Infotrieve]
72. Satoh S, Utsunomiya T, Tsurui K, Kobayashi T, Ikegaki I, Sasaki Y, Asano T. Pharmacological profile of hydroxy fasudil as a selective rho kinase inhibitor on ischemic brain damage. Life Sci. 2001; 69: 1441–1453.[CrossRef][Medline] [Order article via Infotrieve]
73. Niggli V. Rho-kinase in human neutrophils: a role in signalling for myosin light chain phosphorylation and cell migration. FEBS Lett. 1999; 445: 69–72.[CrossRef][Medline] [Order article via Infotrieve]
74. Chodniewicz D, Zhelev DV. Chemoattractant receptor-stimulated F-actin polymerization in the human neutrophil is signaled by 2 distinct pathways. Blood. 2003; 101: 1181–1184.[Abstract/Free Full Text]
75. Niggli V. Signaling to migration in neutrophils: importance of localized pathways. Int J Biochem Cell Biol. 2003; 35: 1619–1638.[CrossRef][Medline] [Order article via Infotrieve]
76. Feske SK, Sorond FA, Henderson GV, Seto M, Hitomi A, Kawasaki K, Sasaki Y, Asano T, Liao JK. Rho-kinase activity is elevated in patients after acute ischemic stroke. Stroke. 2005; 36: 474. Abstract.
77. Stamatovic SM, Keep RF, Kunkel SL, Andjelkovic AV. Potential role of MCP-1 in endothelial cell tight junction ‘opening’: signaling via rho and rho kinase. J Cell Sci. 2003; 116: 4615–4628.[Abstract/Free Full Text]
78. Nicole O, Goldshmidt A, Hamill CE, Sorensen SD, Sastre A, Lyuboslavsky P, Hepler JR, McKeon RJ, Traynelis SF. Activation of protease-activated receptor-1 triggers astrogliosis after brain injury. J Neurosci. 2005; 25: 4319–4329.[Abstract/Free Full Text]
79. Lai CH, Kuo KH, Leo JM. Critical role of actin in modulating BBB permeability. Brain Res Brain Res Rev. 2005; 50: 7–13.[Medline] [Order article via Infotrieve]
80. Dimmeler S, Fleming I, Fisslthaler B, Hermann C, Busse R, Zeiher AM. Activation of nitric oxide synthase in endothelial cells by Akt-dependent phosphorylation. Nature. 1999; 399: 601–605.[CrossRef][Medline] [Order article via Infotrieve]
81. Wolfrum S, Dendorfer A, Rikitake Y, Stalker TJ, Gong Y, Scalia R, Dominiak P, Liao JK. Inhibition of rho-kinase leads to rapid activation of phosphatidylinositol 3-kinase/protein kinase Akt and cardiovascular protection. Arterioscler Thromb Vasc Biol. 2004; 24: 1842–1847.[Abstract/Free Full Text]
82. Noma K, Goto C, Nishioka K, Hara K, Kimura M, Umemura T, Jitsuiki D, Nakagawa K, Oshima T, Chayama K, Yoshizumi M, Higashi Y. Smoking, endothelial function, and rho-kinase in humans. Arterioscler Thromb Vasc Biol. 2005; 25: 2630–2635.[Abstract/Free Full Text]
83. Budzyn K, Marley PD, Sobey CG. Chronic mevastatin modulates receptor-dependent vascular contraction in eNOS-deficient mice. Am J Physiol Regul Integr Comp Physiol. 2004; 287: R342–R348.[Abstract/Free Full Text]
84. Liao JK, Laufs U. Pleiotropic effects of statins. Annu Rev Pharmacol Toxicol. 2005; 45: 89–118.[CrossRef][Medline] [Order article via Infotrieve]
85. Kureishi Y, Luo Z, Shiojima I, Bialik A, Fulton D, Lefer DJ, Sessa WC, Walsh K. The HMG-CoA reductase inhibitor simvastatin activates the protein kinase Akt and promotes angiogenesis in normocholesterolemic animals. Nat Med. 2000; 6: 1004–1010.[CrossRef][Medline] [Order article via Infotrieve]

This article has been cited by other articles: