Statins exert the pleiotropic effects through small GTP-binding protein dissociation stimulator upregulation with a resultant Rac1 degradation

Protein prenylation in islet β-cell function in health and metabolic stress

Protein prenylation has been implicated in a variety of cellular functions, including cytoskeletal remodeling, trafficking and fusion of secretory vesicles with the plasma membrane. It involves incorporation of either a 15-carbon farnesyl or a 20-carbon geranylgeranyl derivative of mevalonic acid into cysteines at the C-terminus of substrate proteins. At least four types of prenyltransferases, namely farnesyl transferase (FTase) and the geranylgeranyl transferases I-III (GGTase-I, II, and III) have been identified in mammalian cells. Published evidence suggests expression of functionally active forms of these prenyltransferases and their candidate substrate proteins in human islets, rodent islets, and clonal β-cells. Pharmacological and molecular biological evidence implicates requisite roles for protein prenylation in glucose-stimulated insulin secretion. Evidence is also emerging to indicate significant defects in protein prenylome in β-cell models of impaired insulin secretion and diabetes. This review will provide a status update on modulatory roles of protein prenylation, enzymes involved in this signaling pathway, their structural composition and regulation in the context of islet β-cell function in normal health. In addition, experimental evidence on the metabolic fate of protein prenylation pathway in the pancreatic β-cell following chronic exposure to diabetogenic stimuli is reviewed herein. Lastly, crucial gaps in our current understanding, and potential opportunities for future research in this area of islet biology are highlighted.

Statins as an Adjunctive Antithrombotic Agent in Thrombotic Antiphospholipid Syndrome: Mechanisms and Clinical Implications

The thrombotic physiopathology of antiphospholipid syndrome (APS) is complex, heterogeneous, and dynamic. While venous thromboembolism (VTE) is the most common initial presentation, arterial thrombotic events (ATE) become more frequent in advanced stages and are associated with high morbidity and mortality. Despite the use of oral anticoagulants (OACs), thrombotic APS remains associated with a high risk of recurrent thrombosis. Given their potential antithrombotic effects capable of reducing the risk of both VTE and ATE, statins have been proposed as an adjunctive therapy to OACs for patients with APS and recurrent thrombosis. However, this recommendation is primarily based on studies not specifically conducted in APS populations, with only preclinical data or evidence from retrospective observational studies available from APS patients cohorts. For these reasons, this narrative review aims to synthesise the studies evaluating the potential antithrombotic effects of statins in patients with APS, highlighting the progress made and identifying areas for future research.

Rosuvastatin accelerates the healing process of partial-thickness burn wounds in rats by reducing TNF-α levels

Introduction

Burn wound healing is a complex, dynamic process that involves a coordinated cascade of cellular responses and phases. Inflammation, proliferation and remodeling are the main phases of tissue repair, while tumor necrosis factor α (TNF-α) and procalcitonin (PCT) seem to be important mediators affecting the inflammatory state. Our aim was to assess the effect of rosuvastatin on tissue repair after partial thickness burn injury in healthy animals.

Material and methods

In this randomized prospective experimental study, 36 male rats were randomly divided into two groups: placebo-treated (PG) and topical rosuvastatin-treated (SG). Under anesthesia, a partial-thickness burn trauma was induced in the dorsal region of the rats using an iron seal. Tissue samples were collected for histopathological examination as well.

Results

Variables of TNF-α, procalcitonin and macroscopic assessment were normally distributed between the two groups on all studied days. The expression of TNF-α was found to be lower in burn injuries treated with topical rosuvastatin in comparison with placebo-treated animals on days 3, 6 and 9. PCT values in rosuvastatin-treated subgroups were statistically significantly lower than in placebo subgroups. Upon macroscopic examination, a significantly smaller burnt area in the statin-treated group was detected compared to the non-statin group on all days, except for day 3. Histopathological examination demonstrated higher levels of mean neutrophil infiltration in the placebo group (day 3). Finally, fibroblast proliferation, angiogenesis and re-epithelization levels were noted to be higher after the topical application of rosuvastatin.

Conclusions

Rosuvastatin accelerated wound healing and down-regulated TNF-α and PCT levels.

Small GTP-binding protein GDP dissociation stimulator influences cisplatin-induced acute kidney injury via PERK-dependent ER stress

Cisplatin is a common anticancer drug, but its frequent nephrotoxicity limits its clinical use. Small GTP-binding protein GDP dissociation stimulator (smgGDS), a small GTPase chaperone protein, was considerably downregulated during cisplatin-induced acute kidney injury (CDDP-AKI), especially in renal tubular epithelial cells. SmgGDS-knockdown mice was established and found that smgGDS knockdown promoted CDDP-AKI, as demonstrated by an increase in serum creatine, blood urea nitrogen levels and the appearance of tubular patterns. RNA sequencing suggested that protein kinase RNA-like ER kinase (PERK), which bridges mitochondria-associated ER membranes, was involved in smgGDS knockdown following CDDP-AKI, and then identified that smgGDS knockdown increased phosphorylated-PERK in vivo and in vitro. Furthermore, we confirmed that smgGDS deficiency aggravated apoptosis and ER stress in vivo and in vitro. And the ER stress inhibitor 4-Phenylbutyric acid and the inhibition of PERK phosphorylation mitigated smgGDS deficiency-induced ER stress related apoptosis following cisplatin treatment, while the eIF2α phosphorylation inhibitor could not reverse the smgGDS deficiency accelerated cell death. Furthermore, the over-expression of smgGDS could reverse the ER stress and apoptosis caused by CDDP. Overall, smgGDS regulated PERK-dependent ER stress and apoptosis, thereby influencing renal damage. This study identified a target for diagnosing and treating cisplatin-induced acute kidney injury.

Use of Statins in Heart Failure with Preserved Ejection Fraction: Current Evidence and Perspectives

Systemic inflammation and coronary microvascular endothelial dysfunction are essential pathophysiological factors in heart failure (HF) with preserved ejection fraction (HFpEF) that support the use of statins. The pleiotropic properties of statins, such as anti-inflammatory, antihypertrophic, antifibrotic, and antioxidant effects, are generally accepted and may be beneficial in HF, especially in HFpEF. Numerous observational clinical trials have consistently shown a beneficial prognostic effect of statins in patients with HFpEF, while the results of two larger trials in patients with HFrEF have been controversial. Such differences may be related to a more pronounced impact of the pleiotropic properties of statins on the pathophysiology of HFpEF and pro-inflammatory comorbidities (arterial hypertension, diabetes mellitus, obesity, chronic kidney disease) that are more common in HFpEF. This review discusses the potential mechanisms of statin action that may be beneficial for patients with HFpEF, as well as clinical trials that have evaluated the statin effects on left ventricular diastolic function and clinical outcomes in patients with HFpEF.

Gellan gum-based bi-polymeric hydrogel scaffolds loaded with Rosuvastatin calcium: A useful tool for tendon tissue regeneration

Statins have been long used in tissue engineering, besides their marketed hypolipidemic benefits. The aim of this research was to sustain the release of rosuvastatin calcium from bi-polymeric hydrogel scaffolds. A bi-polymer blend technique was used to enhance the mechanical properties of the fabricated hydrogels. Briefly, hydrogels were prepared via crosslinking gellan gum as the main polymer together with a secondary polymer in the presence of Ca2+. The fabricated hydrogels were assessed in terms of % swelling capacity, hydrolytic degradation and % drug released to determine the most efficient carrier system. The selected hydrogel exhibited a swelling capacity of 131.45±1.49 % following 3 weeks in an aqueous environment with a % weight loss of 15.73±1.86 % after 4 weeks post-equilibrium in aqueous medium. The results ensure a proper window for adequate drug diffusion and nutrient exchange. Sustained release was attained where 94.61±2.77 % of rosuvastatin was released at the 4-week mark. Later, FT-IR and DSC, were carried out and suggested the successful crosslinking and formation of new matrix. SEM images demonstrated the porous surface of the hydrogel while a Young's modulus of 888.558±73.549 kPa indicated the suitability of the hydrogel for soft tissue engineering. In-vivo testing involved implanting the selected hydrogel at precisely surgical cuts in the Achilles tendon of male Wistar Albino rats. Upon visual and microscopic evaluation, enhanced rates of fibrous tissue formation, vascularization and collagen expression were clearly noticed in the treatment group.

Estradiol-mediated small GTP-binding protein GDP dissociation stimulator induction contributes to sex differences in resilience to ferroptosis in takotsubo syndrome

BACKGROUND

Declining beneficial cardiovascular actions of estradiol (E2) have been associated with disproportionate susceptibility to takotsubo syndrome (TTS) in postmenopausal women. However, the underlying mechanisms between E2 and this marked disproportion remain unclear. SmgGDS (small GTP-binding protein GDP dissociation stimulator), as a key modulator of cardiovascular disease, plays protective roles in reducing oxidative stress and exerts pleiotropic effects of statins. Whether SmgGDS levels are influenced by E2 status and the effect of SmgGDS on sex differences in TTS are poorly understood.

METHODS

Clinical data were reviewed from TTS inpatients. Echocardiography, immunofluorescence, and immunohistochemistry were performed together with expression analysis to uncover phenotypic and mechanism changes in sex differences in TTS-like wild-type (WT) and SmgGDS± mice. HL-1 cardiomyocytes were used to further examine and validate molecular mechanisms.

RESULTS

In 14 TTS inpatients, TTS had a higher incidence in postmenopausal women as compared to premenopausal women and men. In murine TTS, female WT mice exhibited higher cardiac SmgGDS levels than male WT mice. Ovariectomy reduced SmgGDS expression in female WT mice similar to that observed in male mice, whereas E2 replacement in these ovariectomized (OVX) female mice reversed this effect. The physiological importance of this sex-specific E2-mediated SmgGDS response is underscored by the disparity in cardiac adaptation to isoproterenol (ISO) stimulation between both sexes of WT mice. E2-mediated SmgGDS induction conferred female protection against TTS-like acute cardiac injury involving ferritinophagy-mediated ferroptosis. No such cardioprotection was observed in male WT mice and OVX female. A causal role for SmgGDS in this sex-specific cardioprotective adaptation was indicated, inasmuch as SmgGDS deficiency abolished E2-modulated cardioprotection against ferritinophagy and aggravates TTS progression in both sexes. Consistently, knockdown of SmgGDS in HL-1 cardiomyocytes exacerbated ferroptosis in a ferritinophagy-dependent manner and abrogated the protective role of E2 against ferritinophagy. Mechanistically, our findings revealed that SmgGDS regulated E2-dependent cardioprotective effects via AMPK/mTOR signaling pathway. SmgGDS deficiency abolished E2-conferred protection against ferritinophagy through activating AMPK/mTOR pathway, while treatment with recombinant SmgGDS in HL-1 cells significantly mitigated this pathway-associated ferritinophagy activity.

CONCLUSIONS

These results demonstrate that SmgGDS is a central mediator of E2-conferred female cardioprotection against ferritinophagy-mediated ferroptosis in TTS.

Mechanisms of Coronary Artery Spasm

Recent clinical trials have highlighted that percutaneous coronary intervention in patients with stable angina provides limited additional benefits on top of optimal medical therapy. This has led to much more attention being paid to coronary vasomotion abnormalities regardless of obstructive or non-obstructive arterial segments. Coronary vasomotion is regulated by multiple mechanisms that include the endothelium, vascular smooth muscle cells (VSMCs), myocardial metabolic demand, autonomic nervous system and inflammation. Over the years, several animal models have been developed to explore the central mechanism of coronary artery spasm. This review summarises the landmark studies on the mechanisms of coronary vasospasm demonstrating the central role of Rho-kinase as a molecular switch of VSMC hypercontraction and the important role of coronary adventitial inflammation for Rho-kinase upregulation in VSMCs.

Targeting Rho kinase to restore endothelial barrier function following vascular scaffold implantation

Vascular scaffold implantation induces injury to the intimal layer and causes discontinuity of the regenerated endothelial monolayer, compromising barrier integrity, increasing permeability, and allowing the transmigration of leukocytes and lipoproteins into the subendothelial space. Mechanical vascular wall stretching triggers Ras homolog family member A (RhoA)/Rho kinase-mediated actomyosin contractility and destabilization of adherens junctions, leading to endothelial barrier dysfunction. Assembly of intercellular adhesion and actin cytoskeletal organization of interendothelial junctions are controlled by downregulation of RhoA guanosine triphosphatase (GTPase)-mediated barrier-disruptive activity and upregulation of repressor-activator protein 1 (Rap1) and Ras-related C3 botulinum toxin substrate 1 (Rac1) GTPase-mediated cytoskeletal reorganization, leading to endothelial barrier stabilization. This review highlights the involvement of Rho GTPases in the disruption of endothelial barrier integrity following vascular scaffold implantation and the targeting of downstream Rho-associated protein kinases, which signal the network to restore endothelial barrier integrity and stability.

Update on anti-fibrotic pharmacotherapies in skeletal muscle disease

Fibrosis, defined as an excessive accumulation of extracellular matrix, is the end point of a defective regenerative process, unresolved inflammation and/or chronic damage. Numerous muscle disorders (MD) are characterized by high levels of fibrosis associated with muscle wasting and weakness. Fibrosis alters muscle homeostasis/regeneration and fiber environment and may interfere with gene and cell therapies. Slowing down or reversing fibrosis is a crucial therapeutic goal to maintain muscle identity in the context of therapies. Several pathways are implicated in the modulation of the fibrotic progression and multiple therapeutic compounds targeting fibrogenic signals have been tested in MDs, mostly in the context of Duchenne Muscular Dystrophy. In this review, we present an up-to-date overview of pharmacotherapies that have been tested to reduce fibrosis in the skeletal muscle.

Wound Healing Efficacy of Rosuvastatin Transethosomal Gel, I Optimal Optimization, Histological and In Vivo Evaluation

This study aimed to make a formulation and statistical optimization of transethosomal formulations of rosuvastatin (ROS) to enhance its topical wound healing efficiency. Design-Expert^® software was used to employ I optimal design. The formulation variables in the study were surfactant concentration (%w/v), ethanol concentration (%w/v) and surfactant type (span 60 or tween 80), while the dependent responses were entrapment efficiency percent (EE%), vesicle size (VS) and zeta potential (ZP). The numerical optimization process employed by the design expert software resulted in an optimum formula composed of 0.819439 (%w/v) span 60, 40 (%w/v) ethanol and 100 mg lecithin with a desirability of 0.745. It showed a predicted EE% value of 66.5517 vs. 277.703 nm and a ZP of -33. When it was prepared and validated, it showed less than a 5% deviation from the predicted values. The optimum formula was subjected to further characterizations, such as DSC, XRD, TEM, in vitro release, the effect of aging and wound healing efficiency. The DSC thermogram made a confirmation of the compatibility of ROS with the ingredients used in the formulation. XRD showed the encapsulation of ROS in the transethosomal vesicles. The TEM image pointed out the spherical nature of the nanovesicles with the absence of aggregation. Additionally, the optimum formula revealed an enhancement of drug release in comparison with the drug suspension. It also showed good stability for one month. Furthermore, it revealed good wound healing efficiency when compared with the standard silver sulphadiazine (1% w/w) ointment or the drug-loaded gel, which could be related to the enhanced penetration of the nanosized vesicles of TESMs into the skin, which enhances the wound healing process. So, it could be regarded as a promising carrier of ROS for the treatment of chronic wounds.

RHO GTPase family in hepatocellular carcinoma

RHO GTPases are a subfamily of the RAS superfamily of proteins, which are highly conserved in eukaryotic species and have important biological functions, including actin cytoskeleton reorganization, cell proliferation, cell polarity, and vesicular transport. Recent studies indicate that RHO GTPases participate in the proliferation, migration, invasion and metastasis of cancer, playing an essential role in the tumorigenesis and progression of hepatocellular carcinoma (HCC). This review first introduces the classification, structure, regulators and functions of RHO GTPases, then dissects its role in HCC, especially in migration and metastasis. Finally, we summarize inhibitors targeting RHO GTPases and highlight the issues that should be addressed to improve the potency of these inhibitors.

Pleiotropic Benefits of Statins in Cardiovascular Diseases

In 1976, Japanese microbiologist Akira Endo discovered the first statin as a product of the fungus Penicillium citrinum that inhibited the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase. Their primary mode of action is to lower the blood cholesterol by decreasing hepatic cholesterol production, which upregulates hepatic low-density lipoprotein (LDL) receptors and increases LDL-cholesterol clearance. In addition to cholesterol lowering, statins inhibit other downstream products of the mevalonate pathway, causing the so-called pleiotropic effects. As a result of their pleiotropic effects statins modulate virtually all known processes of atherosclerosis and have beneficial effects outside the cardiovascular system Statins inhibit the post-translational prenylation of small GTP-binding proteins such as Rho, Rac, as well as their downstream effectors such as Rho kinase and nicotinamide adenine dinucleotide phosphate oxidases since they suppress the synthesis of isoprenoid intermediates in the cholesterol biosynthetic pathway altering the expression of endothelial nitric oxide synthase, the stability of atherosclerotic plaques, production of proinflammatory cytokines, reactive oxygen species, platelet reactivity, development of cardiac hypertrophy and fibrosis in cell culture and animal experiments. Inhibition of Rho and Rho-associated coiled-coil containing protein kinase (ROCK), has emerged as the principle mechanisms underlying the pleiotropic effects of statins. However, the relative contributions of statin pleiotropy to clinical outcomes are debatable and difficult to measure because the amount of isoprenoid inhibition by statins corresponds to some extent with the amount of LDL-cholesterol decrease. This article examines some of the existing molecular explanations underlying statin pleiotropy and discusses if they have clinical relevance in cardiovascular diseases.

The pleiotropic benefits of statins include the ability to reduce CD47 and amplify the effect of pro-efferocytic therapies in atherosclerosis

The pleiotropic benefits of statins may result from their impact on vascular inflammation. The molecular process underlying this phenomenon is not fully elucidated. Here, RNA sequencing designed to investigate gene expression patterns following CD47-SIRPα inhibition identifies a link between statins, efferocytosis, and vascular inflammation. In vivo and in vitro studies provide evidence that statins augment programmed cell removal by inhibiting the nuclear translocation of NFκB1 p50 and suppressing the expression of the critical 'don't eat me' molecule, CD47. Statins amplify the phagocytic capacity of macrophages, and thus the anti-atherosclerotic effects of CD47-SIRPα blockade, in an additive manner. Analyses of clinical biobank specimens suggest a similar link between statins and CD47 expression in humans, highlighting the potential translational implications. Taken together, our findings identify efferocytosis and CD47 as pivotal mediators of statin pleiotropy. In turn, statins amplify the anti-atherosclerotic effects of pro-phagocytic therapies independently of any lipid-lowering effect.

An evidence-based review of neuronal cholesterol role in dementia and statins as a pharmacotherapy in reducing risk of dementia

INTRODUCTION

Dementia is a progressive neurodegenerative disorder impairing memory and cognition. Alzheimer's Disease, followed by vascular dementia - the most typical form. Risk factors for vascular dementia include diabetes, cardiovascular disease, hyperlipidemia. Lipids' levels are significantly associated with vascular changes in the brain.

AREAS COVERED

The present article reviews the cholesterol metabolism in the brain, which includes: the synthesis, transport, storage, and elimination process. Additionally, it reviews the role of cholesterol in the pathogenesis of dementia and statin as a therapeutic intervention in dementia. In addition to the above, it further reviews evidence in support of as well as against statin therapy in dementia, recent updates of statin pharmacology, and demerits of use of statin pharmacotherapy.

EXPERT OPINION

Amyloid-β peptides and intraneuronal neurofibrillary tangles are markers of Alzheimer's disease. Evidence shows cholesterol modulates the functioning of enzymes associated with Amyloid-β peptide processing and synthesis. Lowering cholesterol using statin may help prevent or delay the progression of dementia. This paper reviews the role of statin in dementia and recommends extensive future studies, including genetic research, to obtain a precise medication approach for patients with dementia.

RAC1 Activation as a Potential Therapeutic Option in Metastatic Cutaneous Melanoma

Metastasis is a complex process by which cancer cells escape from the primary tumor to colonize distant organs. RAC1 is a member of the RHO family of small guanosine triphosphatases that plays an important role in cancer migration, invasion, angiogenesis and metastasis. RAC1 activation has been related to most cancers, such as cutaneous melanoma, breast, lung, and pancreatic cancer. RAC1P29S driver mutation appears in a significant number of cutaneous melanoma cases. Likewise, RAC1 is overexpressed or hyperactivated via signaling through oncogenic cell surface receptors. Thus, targeting RAC1 represents a promising strategy for cutaneous melanoma therapy, as well as for inhibition of other signaling activation that promotes resistance to targeted therapies. In this review, we focus on the role of RAC1 in metastatic cutaneous melanoma emphasizing the anti-metastatic potential of RAC1- targeting drugs.

Rac GTPase Signaling in Immune-Mediated Mechanisms of Atherosclerosis

Coronary artery disease caused by atherosclerosis is a major cause of morbidity and mortality around the world. Data from preclinical and clinical studies support the belief that atherosclerosis is an inflammatory disease that is mediated by innate and adaptive immune signaling mechanisms. This review sought to highlight the role of Rac-mediated inflammatory signaling in the mechanisms driving atherosclerotic calcification. In addition, current clinical treatment strategies that are related to targeting hypercholesterolemia as a critical risk factor for atherosclerotic vascular disease are addressed in relation to the effects on Rac immune signaling and the implications for the future of targeting immune responses in the treatment of calcific atherosclerosis.

RhoGTPase Signalling in Cancer Progression and Dissemination

Rho GTPases are a family of small G proteins that regulate a wide array of cellular processes related to their key roles controlling the cytoskeleton. On the other hand, cancer is a multi-step disease caused by the accumulation of genetic mutations and epigenetic alterations, from the initial stages of cancer development when cells in normal tissues undergo transformation, to the acquisition of invasive and metastatic traits, responsible for a large number of cancer related deaths. In this review, we discuss the role of Rho GTPase signalling in cancer in every step of disease progression. Rho GTPases contribute to tumour initiation and progression, by regulating proliferation and apoptosis, but also metabolism, senescence and cell stemness. Rho GTPases play a major role in cell migration, and in the metastatic process. They are also involved in interactions with the tumour microenvironment and regulate inflammation, contributing to cancer progression. After years of intensive research, we highlight the importance of relevant models in the Rho GTPase field, and we reflect on the therapeutic opportunities arising for cancer patients.

Plausible Positive Effects of Statins in COVID-19 Patient

Since the onset of the global COVID-19 pandemic, there has been much discussion about the advantages and disadvantages of ongoing chronic drug therapies in SARS-CoV-2-positive patients. These discussions include also statins treatment. The statins are among the most widely used drugs in the global population. Statins aim to lower cholesterol, which is essential for many biological processes but can lead to heart disease if levels are too high; however, also the pleiotropic effects of statins are well known. So could the anti-inflammatory or the potential antiviral effects of statins be helpful in avoiding extreme inflammation and severity in COVID-19? To date, there are conflicting opinions on the effects of statins in the course of COVID-19 infection. The aim of this article is to describe the molecular and pharmacological basis of the pleiotropic effects of statins that could be more involved in the fight against COVID-19 infection and to investigate the current epidemiological evidence in the literature on the current and important topic.

Leptin activates Akt in oesophageal cancer cells via multiple atorvastatin-sensitive small GTPases

Obesity is a risk factor for Barrett's oesophagus and oesophageal adenocarcinoma. Adipose tissue secretes the hormone leptin. Leptin is a growth factor for several cell types, including Barrett's cells and oesophageal adenocarcinoma cells. Statins are associated with reduced rates of Barrett's oesophagus and oesophageal cancer and exhibit anti-cancer effects in vitro. The mechanisms of these effects are not fully established. We have examined the effects of leptin and the lipid-soluble statin, atorvastatin, on signalling via monomeric GTP-binding proteins and Akt. Proliferation and apoptosis were assessed in OE33 cells. Akt activity was quantified by cell-based ELISA and in vitro kinase assay. Specific small-molecule inhibitors and a dominant-negative construct were used to reduce Akt activity. Small GTPases were inhibited using transfection of dominant-negative plasmids, prenylation inhibitors and pretreatment with atorvastatin. Leptin stimulated Akt activity and cell proliferation and inhibited camptothecin-induced apoptosis in an Akt-sensitive manner. Leptin induced phosphorylation of Bad and FOXO1 in an Akt-sensitive manner. Leptin activated Ras, Rac, RhoA and cdc42. Transfection of dominant-negative plasmids confirmed that leptin-induced Akt activation required Ras, RhoA cdc42 but not Rac. Atorvastatin inhibited leptin-induced activation of Ras, RhoA, cdc42 and Akt. Co-treatment with mevalonate prevented these effects of atorvastatin. The protein kinase Akt is essential to the growth-promoting and anti-apoptotic effects of leptin in oesophageal adenocarcinoma cells. Akt is activated via Ras-, Rho- and cdc42-dependant pathways. Atorvastatin reduces leptin-induced Akt activation by inhibiting prenylation of small GTPases. This may explain the reduced incidence of oesophageal adenocarcinoma in statin-users.

Weighted Gene Co-Expression Network Analysis Reveals Key Genes and Potential Drugs in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a prevalent aortic disease that causes high mortality due to asymptomatic gradual expansion and sudden rupture. The underlying molecular mechanisms and effective pharmaceutical therapy for preventing AAA progression have not been fully identified. In this study, we identified the key modules and hub genes involved in AAA growth from the GSE17901 dataset in the Gene Expression Omnibus (GEO) database through the weighted gene co-expression network analysis (WGCNA). Key genes were further selected and validated in the mouse dataset (GSE12591) and human datasets (GSE7084, GSE47472, and GSE57691). Finally, we predicted drug candidates targeting key genes using the Drug-Gene Interaction database. Overall, we identified key modules enriched in the mitotic cell cycle, GTPase activity, and several metabolic processes. Seven key genes (CCR5, ADCY5, ADCY3, ACACB, LPIN1, ACSL1, UCP3) related to AAA progression were identified. A total of 35 drugs/compounds targeting the key genes were predicted, which may have the potential to prevent AAA progression.

The advantages of drug treatment with statins in patients with SARS-CoV-2 infection

On 11 March 2020 the World Health Organization (WHO) declared a status of global pandemic caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (coronavirus disease 2019, COVID-19). The pandemic is currently underway, and to date has caused approximately 2.42 million deaths worldwide. The first vaccines have recently been licensed; however, research continues to identify therapeutic agents to prevent serious complications, such as anti-inflammatory, immunomodulatory, anticoagulant or antiviral agents authorized for other therapeutic indications. Epidemiological evidence shows that advanced age and comorbidities, such as diabetes, heart disease, and dyslipidemia may represent COVID-19 risk factors. In particular, in patients with hypercholesterolemia treated with statins, it is recommended that treatment should not be discontinued if COVID-19 infection occurs. The pleiotropic effects of statins are well known. In this brief review, we propose that the use of statins can potentially protect against SARS-CoV-2-induced tissue damage and improve lung function in COVID-19 patients through several pleiotropic effects. Pleiotropic effects of statins that may be a significant benefit in patients with hypercholesterolemia treated with statins and COVID-19 positive. Recent evidence shows promising results.

Rosuvastatin calcium-based novel nanocubic vesicles capped with silver nanoparticles-loaded hydrogel for wound healing management: optimization employing Box-Behnken design: in vitro and in vivo assessment

Chronic wounds are a serious problem that could cause severe morbidity and even death. The ability of statins including rosuvastatin calcium (RVS) to enhance wound healing was well reported. However, RVS is poorly soluble and has low bioavailability. Thus, this study aimed to prepare and evaluate RVS-loaded nanocubics to enhance its skin performance. In addition, silver nanoparticles (AgNPs) exhibited potent antimicrobial activity, thus, the optimum RVS-loaded nanocubics was capped with AgNPs to evaluate its effect in wound management. Box-Behnken design was adopted to prepare RVS nanocubics. The design investigated the effect of lecithin, poloxamer 407 concentrations and hydration time on vesicle size, zeta potential (ZP), entrapment efficiency (EE%) and in vitro drug release%. Optimum formulation capped with AgNPs was incorporated into a gel base and examined for wound healing efficiency using different pharmacological tests in rats. Nanocubics have shown a mean diameter between 167.2 ± 7.8 and 408 ± 18.4 nm, ZP values ranging from -20.9 ± 1.9 to -53.5 ± 4 mV, EE% equivocated between 31.6 ± 1.4 and 94.4 ± 8.6 and drug release after 12 h between 17.9 ± 1.9 and 68.0 ± 4.0%. The histopathological studies and serum tumour necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) levels confirmed the greater efficacy of RVS nanocubics capped with AgNPs gel in wound healing when compared with gentamicin ointment. RVS-loaded nanocubic vesicles and AgNPs-loaded hydrogel could be considered as a promising platform to enhance the wound healing and tissue repair processes.

Molecular insights of NADPH oxidases and its pathological consequences

Reactive oxygen species (ROS), formed by the partial reduction of oxygen, were for a long time considered to be a byproduct of cellular metabolism. Since, increase in cellular levels of ROS results in oxidative stress leading to damage of nucleic acids, proteins, and lipids resulting in numerous pathological conditions; ROS was considered a bane for aerobic species. Hence, the discovery of NADPH oxidases (NOX), an enzyme family that specifically generates ROS as its prime product came as a surprise to redox biologists. NOX family proteins participate in various cellular functions including cell proliferation and differentiation, regulation of genes and protein expression, apoptosis, and host defence immunological response. Balanced expression and activation of NOX with subsequent production of ROS are critically important to regulate various genes and proteins to maintain homeostasis of the cell. However, dysregulation of NOX activation leading to enhanced ROS levels is associated with various pathophysiologies including diabetes, cardiovascular diseases, neurodegenerative diseases, ageing, atherosclerosis, and cancer. Although our current knowledge on NOX signifies its importance in the normal functioning of various cellular pathways; yet the choice of ROS producing enzymes which can tip the scale from homeostasis toward damage, as mediators of biological functions remain an oddity. Though the role of NOX in maintaining normal cellular functions is now deemed essential, yet its dysregulation leading to catastrophic events cannot be denied. Hence, this review focuses on the involvement of NOX enzymes in various pathological conditions imploring them as possible targets for therapies. SIGNIFICANCE OF THE STUDY: The NOXs are multi-subunit enzymes that generate ROS as a prime product. NOX generated ROS are usually regulated by various molecular factors and play a vital role in different physiological processes. The dysregulation of NOX activity is associated with pathological consequences. Recently, the dynamic proximity of NOX enzymes with different molecular signatures of pathologies has been studied extensively. It is essential to identify the precise role of NOX machinery in its niche during the progression of pathology. Although inhibition of NOX could be a promising approach for therapeutic interventions, it is critical to expand the current understanding of NOX's dynamicity and shed light on their molecular partners and regulators.

The Pleiotropic Effects of Statins - From Coronary Artery Disease and Stroke to Atrial Fibrillation and Ventricular Tachyarrhythmia

Statins, 3-hydroxy-methylglutaryl coenzyme A reductase inhibitors, have been used for decades for the prevention of coronary artery disease and stroke. They act primarily by lowering serum cholesterol through the inhibition of cholesterol synthesis in the liver, which results in the upregulation of low-density lipoprotein receptors in the liver. This results in the removal of low-density lipoproteincholesterol. Studies have suggested that statins may demonstrate additional effects that are independent of their effects on low-density lipoprotein-cholesterol. These have been termed "pleiotropic" effects. Pleiotropic effects may be due to the inhibition of isoprenoid intermediates by statins. Isoprenoid inhibition has effects on the small guanosine triphosphate binding proteins Rac and Rho which in turn effects nicotinamide adenine dinucleotide phosphate oxidases. Therefore, there are changes in endothelial nitric oxide synthase expression, atherosclerotic plaque stability, pro-inflammatory cytokines and reactive oxygen species production, platelet reactivity, and cardiac fibrosis and hypetrophy development. Recently, statins have been compared to the ezetimibe and the recently published outcomes data on the proprotein convertase subtilisin kexin type 9 inhibitors has allowed for a reexamination of statin pleiotropy. As a result of these diverse effects, it has been suggested that statins also have anti-arrhythmic effects. This review focuses on the mechanisms of statin pleiotropy and discusses evidence from the statin clinical trials as well as examining the possible anti-arrhythmic effects atrial fibrillation and ventricular tachyarrhythmias.

Simvastatin provides long-term improvement of left ventricular function and prevents cardiac fibrosis in muscular dystrophy

Duchenne muscular dystrophy (DMD), caused by absence of the protein dystrophin, is a common, degenerative muscle disease affecting 1:5000 males worldwide. With recent advances in respiratory care, cardiac dysfunction now accounts for 50% of mortality in DMD. Recently, we demonstrated that simvastatin substantially improved skeletal muscle health and function in mdx (DMD) mice. Given the known cardiovascular benefits ascribed to statins, the aim of this study was to evaluate the efficacy of simvastatin on cardiac function in mdx mice. Remarkably, in 12‐month old mdx mice, simvastatin reversed diastolic dysfunction to normal after short‐term treatment (8 weeks), as measured by echocardiography in animals anesthetized with isoflurane and administered dobutamine to maintain a physiological heart rate. This improvement in diastolic function was accompanied by increased phospholamban phosphorylation in simvastatin‐treated mice. Echocardiography measurements during long‐term treatment, from 6 months up to 18 months of age, showed that simvastatin significantly improved in vivo cardiac function compared to untreated mdx mice, and prevented fibrosis in these very old animals. Cardiac dysfunction in DMD is also characterized by decreased heart rate variability (HRV), which indicates autonomic function dysregulation. Therefore, we measured cardiac ECG and demonstrated that short‐term simvastatin treatment significantly increased heart rate variability (HRV) in 14‐month‐old conscious mdx mice, which was reversed by atropine. This finding suggests that enhanced parasympathetic function is likely responsible for the improved HRV mediated by simvastatin. Together, these findings indicate that simvastatin markedly improves cardiac health and function in dystrophic mice, and therefore may provide a novel approach for treating cardiomyopathy in DMD.

Rac1 Signaling: From Intestinal Homeostasis to Colorectal Cancer Metastasis

The small GTPase Rac1 has been implicated in a variety of dynamic cell biological processes, including cell proliferation, cell survival, cell-cell contacts, epithelial mesenchymal transition (EMT), cell motility, and invasiveness. These processes are orchestrated through the fine tuning of Rac1 activity by upstream cell surface receptors and effectors that regulate the cycling Rac1-GDP (off state)/Rac1-GTP (on state), but also through the tuning of Rac1 accumulation, activity, and subcellular localization by post translational modifications or recruitment into molecular scaffolds. Another level of regulation involves Rac1 transcripts stability and splicing. Downstream, Rac1 initiates a series of signaling networks, including regulatory complex of actin cytoskeleton remodeling, activation of protein kinases (PAKs, MAPKs) and transcription factors (NFkB, Wnt/β-catenin/TCF, STAT3, Snail), production of reactive oxygen species (NADPH oxidase holoenzymes, mitochondrial ROS). Thus, this GTPase, its regulators, and effector systems might be involved at different steps of the neoplastic progression from dysplasia to the metastatic cascade. After briefly placing Rac1 and its effector systems in the more general context of intestinal homeostasis and in wound healing after intestinal injury, the present review mainly focuses on the several levels of Rac1 signaling pathway dysregulation in colorectal carcinogenesis, their biological significance, and their clinical impact.

Emerging Challenges of Radiation-Associated Cardiovascular Dysfunction (RACVD) in Modern Radiation Oncology: Clinical Practice, Bench Investigation, and Multidisciplinary Care

Radiotherapy (RT) is a crucial treatment modality in managing cancer patients. However, irradiation dose sprinkling to tumor-adjacent normal tissues is unavoidable, generating treatment toxicities, such as radiation-associated cardiovascular dysfunction (RACVD), particularly for those patients with combined therapies or pre-existing adverse features/comorbidities. Radiation oncologists implement several efforts to decrease heart dose for reducing the risk of RACVD. Even applying the deep-inspiration breath-hold (DIBH) technique, the risk of RACVD is though reduced but still substantial. Besides, available clinical methods are limited for early detecting and managing RACVD. The present study reviewed emerging challenges of RACVD in modern radiation oncology, in terms of clinical practice, bench investigation, and multidisciplinary care. Several molecules are potential for serving as biomarkers and therapeutic targets. Of these, miRNAs, endogenous small non-coding RNAs that function in regulating gene expression, are of particular interest because low-dose irradiation, i.e., 200 mGy (one-tenth of conventional RT daily dose) induces early changes of pro-RACVD miRNA expression. Moreover, several miRNAs, e.g., miR-15b and miR21, involve in the development of RACVD, further demonstrating the potential bio-application in RACVD. Remarkably, many RACVDs are late RT sequelae, characterizing highly irreversible and progressively worse. Thus, multidisciplinary care from oncologists and cardiologists is crucial. Combined managements with commodities control (such as hypertension, hypercholesterolemia, and diabetes), smoking cessation, and close monitoring are recommended. Some agents show abilities for preventing and managing RACVD, such as statins and angiotensin-converting enzyme inhibitors (ACEIs); however, their real roles should be confirmed by further prospective trials.

Reactive oxygen species in cardiovascular health and disease: special references to nitric oxide, hydrogen peroxide, and Rho-kinase

The interaction between endothelial cells and vascular smooth muscle cells (VSMC) plays an important role in regulating cardiovascular homeostasis. Endothelial cells synthesize and release endothelium-derived relaxing factors (EDRFs), including vasodilator prostaglandins, nitric oxide (NO), and endothelium-dependent hyperpolarization (EDH) factors. Importantly, the contribution of EDRFs to endothelium-dependent vasodilatation markedly varies in a vessel size-dependent manner; NO mainly mediates vasodilatation of relatively large vessels, while EDH factors in small resistance vessels. We have previously identified that endothelium-derived hydrogen peroxide (H₂O₂) is an EDH factor especially in microcirculation. Several lines of evidence indicate the importance of the physiological balance between NO and H₂O₂/EDH factor. Rho-kinase was identified as the effectors of the small GTP-binding protein, RhoA. Both endothelial NO production and NO-mediated signaling in VSMC are targets and effectors of the RhoA/Rho-kinase pathway. In endothelial cells, the RhoA/Rho-kinase pathway negatively regulates NO production. On the contrary, the pathway enhances VSMC contraction with resultant occurrence of coronary artery spasm and promotes the development of oxidative stress and vascular remodeling. In this review, I will briefly summarize the current knowledge on the regulatory roles of endothelium-derived relaxing factors, with special references to NO and H₂O₂/EDH factor, in relation to Rho-kinase, in cardiovascular health and disease.

Geranylgeraniol prevents statin-induced skeletal muscle fatigue without causing adverse effects in cardiac or vascular smooth muscle performance

The administration of geranylgeranyl pyrophosphate (GGPP) (or its precursor, geranylgeraniol [GGOH]) has been shown by several in vitro studies to be capable of abrogating statin-induced myotoxicity. Nonetheless, the potential of GGPP repletion to prevent statin-associated muscle symptoms (SAMS) in vivo is yet to be investigated. Therefore, this study aimed to evaluate the ability of GGOH to prevent SAMS in rodents. Female Wistar rats (12 weeks of age) were randomised to 1 of 4 treatment groups: control, control with GGOH, simvastatin or simvastatin with GGOH. Ex vivo assessment of force production was conducted in skeletal muscles of varying fiber composition. Ex vivo left ventricular performance and blood vessel function was also assessed to determine if the administration of GGOH caused adverse changes in these parameters. Statin administration was associated with reduced force production in fast-twitch glycolytic muscle, but coadministration with GGOH completely abrogated this effect. Additionally, GGOH improved the performance of muscles not adversely affected by simvastatin (ie, those with a greater proportion of slow-twitch oxidative fibers), and increased force production in the control animals. Neither control nor statin-treated rodents given GGOH exhibited adverse changes in cardiac function. Vascular relaxation was also maintained following treatment with GGOH. The findings of this study demonstrate that GGOH can prevent statin-induced skeletal muscle fatigue in rodents without causing adverse changes in cardiovascular function. Further studies to elucidate the exact mechanisms underlying the effects observed in this investigation are warranted.

The effect and molecular mechanism of statins on the expression of human anti-coagulation genes

Statins are potent lipid-lowering drugs. Large prospective clinical trials have shown the anti-thrombotic effect of statins, e.g., preventing deep vein thrombosis. However, the mechanism underlying the beneficial effect of statins in reducing thrombus formation remains to be established. We, thus, conduct this study to investigate the potential molecular mechanisms. The cultured human hepatoma cells (HepG2) were used as the in vitro model. The human protein C gene promoter was cloned into the luciferase reporter to study the transcriptional regulation of human protein C gene. Wistar rats fed with simvastatin (5 mg/kg day) were used as the in vivo model. We found that simvastatin increased the expression of protein C in hepatocytes (361 ± 64% and 313 ± 59% after 2 h and 6 h of stimulation, respectively, both p < 0.01). In the animal study, the serum protein C levels were increased in the simvastatin-treated group (7 ± 2.2 unit/ml vs 23.4 ± 19.3 unit/ml and 23.4 ± 18.2 unit/ml and 1 and 2 weeks of treatment, respectively, both p < 0.05). Regarding the possible molecular mechanism, we found that the level of hepatocyte nuclear factor 1α (HNF1α) was also increased in both the in vivo and in vitro models. We found that the protein C promoter activity was increased by simvastatin, and this effect was inhibited by HNF1α knockdown and constitutively active Rac1. Therefore, stains may modulate protein C expression through small GTPase Rac 1 and HNF1α.

Small GTP-Binding Protein GDP Dissociation Stimulator Prevents Thoracic Aortic Aneurysm Formation and Rupture by Phenotypic Preservation of Aortic Smooth Muscle Cells

BACKGROUND

Thoracic aortic aneurysm (TAA) and dissection are fatal diseases that cause aortic rupture and sudden death. The small GTP-binding protein GDP dissociation stimulator (SmgGDS) is a crucial mediator of the pleiotropic effects of statins. Previous studies revealed that reduced force generation in aortic smooth muscle cells (AoSMCs) causes TAA and thoracic aortic dissection.

METHODS

To examine the role of SmgGDS in TAA formation, we used an angiotensin II (1000 ng·min^-1·kg^-1, 4 weeks)-induced TAA model.

RESULTS

We found that 33% of Apoe^-/- SmgGDS^+/- mice died suddenly as a result of TAA rupture, whereas there was no TAA rupture in Apoe^-/- control mice. In contrast, there was no significant difference in the ratio of abdominal aortic aneurysm rupture between the 2 genotypes. We performed ultrasound imaging every week to follow up the serial changes in aortic diameters. The diameter of the ascending aorta progressively increased in Apoe^-/- SmgGDS^+/- mice compared with Apoe^-/- mice, whereas that of the abdominal aorta remained comparable between the 2 genotypes. Histological analysis of Apoe^-/- SmgGDS^+/- mice showed dissections of major thoracic aorta in the early phase of angiotensin II infusion (day 3 to 5) and more severe elastin degradation compared with Apoe^-/- mice. Mechanistically, Apoe^-/- SmgGDS^+/- mice showed significantly higher levels of oxidative stress, matrix metalloproteinases, and inflammatory cell migration in the ascending aorta compared with Apoe^-/- mice. For mechanistic analyses, we primary cultured AoSMCs from the 2 genotypes. After angiotensin II (100 nmol/L) treatment for 24 hours, Apoe^-/- SmgGDS^+/- AoSMCs showed significantly increased matrix metalloproteinase activity and oxidative stress levels compared with Apoe^-/- AoSMCs. In addition, SmgGDS deficiency increased cytokines/chemokines and growth factors in AoSMCs. Moreover, expressions of fibrillin-1 ( FBN1), α-smooth muscle actin ( ACTA2), myosin-11 ( MYH11), MYLLK, and PRKG1, which are force generation genes, were significantly reduced in Apoe^-/- SmgGDS^+/- AoSMCs compared with Apoe^-/- AoSMCs. A similar tendency was noted in AoSMCs from patients with TAA compared with those from control subjects. Finally, local delivery of the SmgGDS gene construct reversed the dilation of the ascending aorta in Apoe^-/- SmgGDS^+/- mice.

CONCLUSIONS

These results suggest that SmgGDS is a novel therapeutic target for the prevention and treatment of TAA.

The role of pericytes in brain disorders: from the periphery to the brain

It is becoming increasingly apparent that disorders of the brain microvasculature contribute to many neurological disorders. In recent years it has become clear that a major player in these events is the capillary pericyte which, in the brain, is now known to control the blood-brain barrier, regulate blood flow, influence immune cell entry and be crucial for angiogenesis. In this review we consider the under-explored possibility that peripheral diseases which affect the microvasculature, such as hypertension, kidney disease and diabetes, produce central nervous system (CNS) dysfunction by mechanisms affecting capillary pericytes within the CNS. We highlight how cellular messengers produced peripherally can act via signalling pathways within CNS pericytes to reshape blood vessels, restrict blood flow or compromise blood-brain barrier function, thus causing neuronal dysfunction. Increased understanding of how renin-angiotensin, Rho-kinase and PDGFRβ signalling affect CNS pericytes may suggest novel therapeutic approaches to reducing the CNS effects of peripheral disorders.

Targeting angiogenesis in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) represents one of the most devastating types of muscular dystrophies which affect boys already at early childhood. Despite the fact that the primary cause of the disease, namely the lack of functional dystrophin is known already for more than 30 years, DMD still remains an incurable disease. Thus, an enormous effort has been made during recent years to reveal novel mechanisms that could provide therapeutic targets for DMD, especially because glucocorticoids treatment acts mostly symptomatic and exerts many side effects, whereas the effectiveness of genetic approaches aiming at the restoration of functional dystrophin is under the constant debate. Taking into account that dystrophin expression is not restricted to muscle cells, but is present also in, e.g., endothelial cells, alterations in angiogenesis process have been proposed to have a significant impact on DMD progression. Indeed, already before the discovery of dystrophin, several abnormalities in blood vessels structure and function have been revealed, suggesting that targeting angiogenesis could be beneficial in DMD. In this review, we will summarize current knowledge about the angiogenesis status both in animal models of DMD as well as in DMD patients, focusing on different organs as well as age- and sex-dependent effects. Moreover, we will critically discuss some approaches such as modulation of vascular endothelial growth factor or nitric oxide related pathways, to enhance angiogenesis and attenuate the dystrophic phenotype. Additionally, we will suggest the potential role of other mediators, such as heme oxygenase-1 or statins in those processes.

Small GTPases and Their Role in Vascular Disease

Over eighty million people in the United States have cardiovascular disease that can affect the heart causing myocardial infarction; the carotid arteries causing stroke; and the lower extremities leading to amputation. The treatment for end-stage cardiovascular disease is surgical—either endovascular therapy with balloons and stents—or open reconstruction to reestablish blood flow. All interventions damage or destroy the protective inner lining of the blood vessel—the endothelium. An intact endothelium is essential to provide a protective; antithrombotic lining of a blood vessel. Currently; there are no agents used in the clinical setting that promote reendothelialization. This process requires migration of endothelial cells to the denuded vessel; proliferation of endothelial cells on the denuded vessel surface; and the reconstitution of the tight adherence junctions responsible for the formation of an impermeable surface. These processes are all regulated in part and are dependent on small GTPases. As important as the small GTPases are for reendothelialization, dysregulation of these molecules can result in various vascular pathologies including aneurysm formation, atherosclerosis, diabetes, angiogenesis, and hypertension. A better understanding of the role of small GTPases in endothelial cell migration is essential to the development for novel agents to treat vascular disease.

Chitosan-Coated Nanoparticles: Effect of Chitosan Molecular Weight on Nasal Transmucosal Delivery

Drug delivery to the brain represents a challenge, especially in the therapy of central nervous system malignancies. Simvastatin (SVT), as with other statins, has shown potential anticancer properties that are difficult to exploit in the central nervous system (CNS). In the present work the physico⁻chemical, mucoadhesive, and permeability-enhancing properties of simvastatin-loaded poly-ε-caprolactone nanocapsules coated with chitosan for nose-to-brain administration were investigated. Lipid-core nanocapsules coated with chitosan (LNCchit) of different molecular weight (MW) were prepared by a novel one-pot technique, and characterized for particle size, surface charge, particle number density, morphology, drug encapsulation efficiency, interaction between surface nanocapsules with mucin, drug release, and permeability across two nasal mucosa models. Results show that all formulations presented adequate particle sizes (below 220 nm), positive surface charge, narrow droplet size distribution (PDI < 0.2), and high encapsulation efficiency. Nanocapsules presented controlled drug release and mucoadhesive properties that are dependent on the MW of the coating chitosan. The results of permeation across the RPMI 2650 human nasal cell line evidenced that LNCchit increased the permeation of SVT. In particular, the amount of SVT that permeated after 4 hr for nanocapsules coated with low-MW chitosan, high-MW chitosan, and control SVT was 13.9 ± 0.8 μg, 9.2 ± 1.2 µg, and 1.4 ± 0.2 µg, respectively. These results were confirmed by SVT ex vivo permeation across rabbit nasal mucosa. This study highlighted the suitability of LNCchit as a promising strategy for the administration of simvastatin for a nose-to-brain approach for the therapy of brain tumors.

Hydroxymethylglutaryl-CoA reductase inhibitors (statins) for the treatment of sepsis in adults - A systematic review and meta-analysis

OBJECTIVES

The pleiotropic effect of hydroxymethylglutaryl-CoA reductase inhibitors (statins) might have a beneficial effect in sepsis through several mechanisms. The aim was to assess the efficacy and safety of statins, compared with placebo, for the treatment of sepsis in adults.

METHODS

We searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2017, Issue 12), OVID MEDLINE (from 1966 to January 2018), Embase (Ovid SP, from 1974 to January 2018), and LILACS (from 1986 to January 2018). We also searched the trial registries ISRCTN and ClinicalTrials.gov to January 2018. The eligibility criteria were randomized controlled trials comparing the treatment of statins versus placebo in adult patients who were hospitalized due to sepsis. Participants were adults (16 years and older) hospitalized because of sepsis or who developed sepsis during admission. Interventions were treatment with hydroxymethylglutaryl-CoA reductase inhibitors (statins) versus no treatment or placebo. We performed a systematic review of all randomized controlled trials published until January 2018, assessing the efficacy and safety of statins in sepsis treatment. Two primary outcomes were assessed: 30-day overall mortality and deterioration to severe sepsis during management. Secondary outcomes were hospital mortality, need for mechanical ventilation and drug related adverse events.

RESULTS

Fourteen trials evaluating 2628 patients were included. Statins did not reduce 30-day all-cause mortality neither in all patients (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.83-1.10), nor in a subgroup of patients with severe sepsis (RR 0.97, 95% CI 0.84-1.12). The certainty of evidence for both outcomes was high. There was no change in the rate of adverse events between study arms (RR 1.24, 95% CI 0.94 to 1.63). The certainty of evidence for this outcome was high.

CONCLUSIONS

The use of statin therapy in adults for the indication of sepsis is not recommended.

Targeting Rac and Cdc42 GTPases in Cancer

Rac and Cdc42 are small GTPases that have been linked to multiple human cancers and are implicated in epithelial to mesenchymal transition, cell-cycle progression, migration/invasion, tumor growth, angiogenesis, and oncogenic transformation. With the exception of the P29S driver mutation in melanoma, Rac and Cdc42 are not generally mutated in cancer, but are overexpressed (gene amplification and mRNA upregulation) or hyperactivated. Rac and Cdc42 are hyperactivated via signaling through oncogenic cell surface receptors, such as growth factor receptors, which converge on the guanine nucleotide exchange factors that regulate their GDP/GTP exchange. Hence, targeting Rac and Cdc42 represents a promising strategy for precise cancer therapy, as well as for inhibition of bypass signaling that promotes resistance to cell surface receptor-targeted therapies. Therefore, an understanding of the regulatory mechanisms of these pivotal signaling intermediates is key for the development of effective inhibitors. In this review, we focus on the role of Rac and Cdc42 in cancer and summarize the regulatory mechanisms, inhibitory efficacy, and the anticancer potential of Rac- and Cdc42-targeting agents. Cancer Res; 78(12); 3101-11. ©2018 AACR.

Neuronal Rho GTPase Rac1 elimination confers neuroprotection in a mouse model of permanent ischemic stroke

The Rho GTPase Rac1 is a multifunctional protein involved in distinct pathways ranging from development to pathology. The aim of the present study was to unravel the contribution of neuronal Rac1 in regulating the response to brain injury induced by permanent focal cerebral ischemia (pMCAO). Our results show that pMCAO significantly increased total Rac1 levels in wild type mice, mainly through rising nuclear Rac1, while a reduction in Rac1 activation was observed. Such changes preceded cell death induced by excitotoxic stress. Pharmacological inhibition of Rac1 in primary neuronal cortical cells prevented the increase in oxidative stress induced after overactivation of glutamate receptors. However, this was not sufficient to prevent the associated neuronal cell death. In contrast, RNAi-mediated knock down of Rac1 in primary cortical neurons prevented cell death elicited by glutamate excitotoxicity and decreased the activity of NADPH oxidase. To test whether in vivo down regulation of neuronal Rac1 was neuroprotective after pMCAO, we used tamoxifen-inducible neuron-specific conditional Rac1-knockout mice. We observed a significant 50% decrease in brain infarct volume of knockout mice and a concomitant increase in HIF-1α expression compared to littermate control mice, demonstrating that ablation of Rac1 in neurons is neuroprotective. Transmission electron microscopy performed in the ischemic brain showed that lysosomes in the infarct of Rac1- knockout mice were preserved at similar levels to those of non-infarcted tissue, while littermate mice displayed a decrease in the number of lysosomes, further corroborating the notion that Rac1 ablation in neurons is neuroprotective. Our results demonstrate that Rac1 plays important roles in the ischemic pathological cascade and that modulation of its levels is of therapeutic interest.

Structure-based analysis of the guanine nucleotide exchange factor SmgGDS reveals armadillo-repeat motifs and key regions for activity and GTPase binding

Small GTPases are molecular switches that have critical biological roles and are controlled by GTPase-activating proteins and guanine nucleotide exchange factors (GEFs). The smg GDP dissociation stimulator (SmgGDS) protein functions as a GEF for the RhoA and RhoC small GTPases. SmgGDS has various regulatory roles, including small GTPase trafficking and localization and as a molecular chaperone, and interacts with many small GTPases possessing polybasic regions. Two SmgGDS splice variants, SmgGDS-558 and SmgGDS-607, differ in GEF activity and binding affinity for RhoA depending on the lipidation state, but the reasons for these differences are unclear. Here we determined the crystal structure of SmgGDS-558, revealing a fold containing tandem copies of armadillo repeats not present in other GEFs. We also observed that SmgGDS harbors distinct positively and negatively charged regions, both of which play critical roles in binding to RhoA and GEF activity. This is the first report demonstrating a relationship between the molecular function and atomic structure of SmgGDS. Our findings indicate that the two SmgGDS isoforms differ in GTPase binding and GEF activity, depending on the lipidation state, thus providing useful information about the cellular functions of SmgGDS in cells.

Rho GTPases as therapeutic targets in cancer (Review)

Rho GTPases are key molecular switches controlling the transduction of external signals to cytoplasmic and nuclear effectors. In the last few years, the development of genetic and pharmacological tools has allowed a more precise definition of the specific roles of Rho GTPases in cancer. The aim of the present review is to describe the cellular functions regulated by these proteins with focus in deregulated signals present in malignant tumors. Finally, we describe the state of the art in search of different experimental therapeutic strategies with Rho GTPases as molecular targets.

Rac1 in human diseases: The therapeutic potential of targeting Rac1 signaling regulatory mechanisms

Abnormal Rac1 signaling is linked to a number of debilitating human diseases, including cancer, cardiovascular diseases and neurodegenerative disorders. As such, Rac1 represents an attractive therapeutic target, yet the search for effective Rac1 inhibitors is still underway. Given the adverse effects associated with Rac1 signaling perturbation, cells have evolved several mechanisms to ensure the tight regulation of Rac1 signaling. Thus, characterizing these mechanisms can provide invaluable information regarding major cellular events that lead to aberrant Rac1 signaling. Importantly, this information can be utilized to further facilitate the development of effective pharmacological modulators that can restore normal Rac1 signaling. In this review, we focus on the pathological role of Rac1 signaling, highlighting the benefits and potential drawbacks of targeting Rac1 in a clinical setting. Additionally, we provide an overview of available compounds that target key Rac1 regulatory mechanisms and discuss future therapeutic avenues arising from our understanding of these mechanisms.

CYP2J2 metabolites, epoxyeicosatrienoic acids, attenuate Ang II-induced cardiac fibrotic response by targeting Gα12/13

The arachidonic acid-cytochrome P450 2J2-epoxyeicosatrienoic acid (AA-CYP2J2-EET) metabolic pathway has been identified to be protective in the cardiovascular system. This study explored the effects of the AA-CYP2J2-EET metabolic pathway on cardiac fibrosis from the perspective of cardiac fibroblasts and underlying mechanisms. In in vivo studies, 8-week-old male CYP2J2 transgenic mice (aMHC-CYP2J2-Tr) and littermates were infused with angiotensin II (Ang II) or saline for 2 weeks. Results showed that CYP2J2 overexpression increased EET production. Meanwhile, impairment of cardiac function and fibrotic response were attenuated by CYP2J2 overexpression. The effects of CYP2J2 were associated with reduced activation of the α subunits of G12 family G proteins (Gα_12/13)/RhoA/Rho kinase (ROCK) cascade and elevation of the NO/cyclic guanosine monophosphate (cGMP) level in cardiac tissue. In in vitro studies, cardiac fibroblast activation, proliferation, migration, and collagen production induced by Ang II were associated with activation of the Gα_12/13/RhoA/ROCK pathway, which was inhibited by exogenous 11,12-EET. Moreover, silencing of Gα_12/13 or RhoA exerted similar effects as 11,12-EET. Furthermore, inhibitory effects of 11,12-EET on Gα_12/13 were blocked by NO/cGMP pathway inhibitors. Our findings indicate that enhancement of the AA-CYP2J2-EET metabolic pathway by CYP2J2 overexpression attenuates Ang II-induced cardiac dysfunction and fibrosis by reducing the fibrotic response of cardiac fibroblasts by targeting the Gα_12/13/RhoA/ROCK pathway via NO/cGMP signaling.

Pleiotropic Effects of Statins on the Cardiovascular System

The statins have been used for 30 years to prevent coronary artery disease and stroke. Their primary mechanism of action is the lowering of serum cholesterol through inhibiting hepatic cholesterol biosynthesis thereby upregulating the hepatic low-density lipoprotein (LDL) receptors and increasing the clearance of LDL-cholesterol. Statins may exert cardiovascular protective effects that are independent of LDL-cholesterol lowering called pleiotropic effects. Because statins inhibit the production of isoprenoid intermediates in the cholesterol biosynthetic pathway, the post-translational prenylation of small GTP-binding proteins such as Rho and Rac, and their downstream effectors such as Rho kinase and nicotinamide adenine dinucleotide phosphate oxidases are also inhibited. In cell culture and animal studies, these effects alter the expression of endothelial nitric oxide synthase, the stability of atherosclerotic plaques, the production of proinflammatory cytokines and reactive oxygen species, the reactivity of platelets, and the development of cardiac hypertrophy and fibrosis. The relative contributions of statin pleiotropy to clinical outcomes, however, remain a matter of debate and are hard to quantify because the degree of isoprenoid inhibition by statins correlates to some extent with the amount of LDL-cholesterol reduction. This review examines some of the currently proposed molecular mechanisms for statin pleiotropy and discusses whether they could have any clinical relevance in cardiovascular disease.

Statins and Cognition in Parkinson's Disease

BACKGROUND

The relationship between statins and cognition in Parkinson's disease (PD) is poorly understood.

OBJECTIVES

Analyses were performed to determine associations between statin use and cross-sectional and longitudinal cognitive performance in PD.

METHODS

Neuropsychological tests, medication logs, and ratings of functional abilities were collected from 313 PD participants longitudinally.

RESULTS

At baseline, statin users (SU; N = 129) were older, more likely male, and had shorter PD duration than non-statin users (NSU; N = 184). In Cross-sectional analysis, SU performed better on global cognition, Trails B, semantic fluency, and phonemic fluency tasks. Rate of long-term global cognitive (Dementia Rating Scale-2 and MoCA) decline was significantly less in SU.

Platelet tissue factor activity and membrane cholesterol are increased in hypercholesterolemia and normalized by rosuvastatin, but not by atorvastatin

BACKGROUND AND AIMS

High plasma LDL-cholesterol (LDL-C) and platelet responses have major pathogenic roles in atherothrombosis. Thus, statins and anti-platelet drugs constitute mainstays in cardiovascular prevention/treatment. However, the role of platelet tissue factor-dependent procoagulant activity (TF-PCA) has remained unexplored in hypercholesterolemia. We aimed to study platelet TF-PCA and its relationship with membrane cholesterol in vitro and in 45 hypercholesterolemic patients (HC-patients) (LDL-C >3.37 mmol/L, 130 mg/dL) and 37 control subjects (LDL-C <3.37 mmol/L). The effect of 1-month administration of 80 mg/day atorvastatin (n = 21) and 20 mg/day rosuvastatin (n = 24) was compared.

METHODS

Platelet TF-PCA was induced by GPIbα activation with VWF-ristocetin.

RESULTS

Cholesterol-enriched platelets in vitro had augmented aggregation/secretion and platelet FXa generation (1.65-fold increase, p = 0.01). HC-patients had 1.5-, 2.3- and 2.5-fold increases in platelet cholesterol, TF protein and activity, respectively; their platelets had neither hyper-aggregation nor endogenous thrombin generation (ETP). Rosuvastatin, but not atorvastatin, normalized platelet cholesterol, TF protein and FXa generation. It also increased slightly the plasma HDL-C levels, which correlated negatively with TF-PCA.

CONCLUSIONS

Platelets from HC-patients were not hyper-responsive to low concentrations of classical agonists and had normal PRP-ETP, before and after statin administration. However, washed platelets from HC-patients had increased membrane cholesterol, TF protein and TF-PCA. The platelet TF-dependent PCA was specifically expressed after VWF-induced GPIbα activation. Rosuvastatin, but not atorvastatin treatment, normalized the membrane cholesterol, TF protein and TF-PCA in HC-patients, possibly unveiling a new pleiotropic effect of rosuvastatin. Modulation of platelet TF-PCA may become a novel target to prevent/treat atherothrombosis without increasing bleeding risks.

RhoA/Rho-Kinase in the Cardiovascular System

Twenty years ago, Rho-kinase was identified as an important downstream effector of the small GTP-binding protein, RhoA. Thereafter, a series of studies demonstrated the important roles of Rho-kinase in the cardiovascular system. The RhoA/Rho-kinase pathway is now widely known to play important roles in many cellular functions, including contraction, motility, proliferation, and apoptosis, and its excessive activity induces oxidative stress and promotes the development of cardiovascular diseases. Furthermore, the important role of Rho-kinase has been demonstrated in the pathogenesis of vasospasm, arteriosclerosis, ischemia/reperfusion injury, hypertension, pulmonary hypertension, and heart failure. Cyclophilin A is secreted by vascular smooth muscle cells and inflammatory cells and activated platelets in a Rho-kinase-dependent manner, playing important roles in a wide range of cardiovascular diseases. Thus, the RhoA/Rho-kinase pathway plays crucial roles under both physiological and pathological conditions and is an important therapeutic target in cardiovascular medicine. Recently, functional differences between ROCK1 and ROCK2 have been reported in vitro. ROCK1 is specifically cleaved by caspase-3, whereas granzyme B cleaves ROCK2. However, limited information is available on the functional differences and interactions between ROCK1 and ROCK2 in the cardiovascular system in vivo. Herein, we will review the recent advances about the importance of RhoA/Rho-kinase in the cardiovascular system.

Pleiotropic effects of statins on acute kidney injury: involvement of Krüppel-like factor 4

Statins, the inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, are potent cholesterol-lowering drugs used for primary and secondary prevention of coronary artery disease. They also possess multiple beneficial effects independent of their cholesterol-lowering properties, which are called as their "pleiotropic" effects. The results of recent studies have revealed that statins exert their pleiotropic effects in the kidneys, in that they are protective against acute kidney injury (AKI). Moreover, Krüppel-like factor 4, a zinc-finger transcription factor, in endothelial cells has been identified as a novel mediator of statins. This article summarizes the pleiotropic effects of statins on AKI, and reviews the recent progress in our understanding of the regulatory mechanisms involved in statin-mediated protection against AKI.

Mitigation of tight junction protein dysfunction in lung microvascular endothelial cells with pitavastatin

BACKGROUND

Statin use in individuals with chronic obstructive pulmonary disease (COPD) with coexisting cardiovascular disease is associated with a reduced risk of exacerbations. The mechanisms by which statin plays a role in the pathophysiology of COPD have not been defined. To explore the mechanisms involved, we investigated the effect of statin on endothelial cell function, especially endothelial cell tight junctions.

METHOD

We primarily assessed whether pitavastatin could help mitigate the development of emphysema induced by continuous cigarette smoking (CS) exposure. We also investigated the activation of liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK) signaling, which plays a role in maintaining endothelial functions, important tight junction proteins, zonula occludens (ZO)-1 and claudin-5 expression, and lung microvascular endothelial cell permeability.

RESULTS

We found that pitavastatin prevented the CS-induced decrease in angiomotin-like protein 1 (AmotL1)-positive vessels via the activation of LKB1/AMPK signaling and IFN-γ-induced hyperpermeability of cultured human lung microvascular endothelial cells by maintaining the levels of AmotL1, ZO-1, and claudin-5 expression at the tight junctions.

CONCLUSION

Our results indicate that the maintenance of lung microvascular endothelial cells by pitavastatin prevents tight junction protein dysfunctions induced by CS. These findings may ultimately lead to new and novel therapeutic targets for patients with COPD.