Pitavastatin Regulates Helper T-Cell Differentiation and Ameliorates Autoimmune Myocarditis in Mice

Role of CCRL2 in the Pathogenesis of Experimental Autoimmune Myocarditis via P21-Activated Kinase 1/NOD-Like Receptor Protein 3 Pathway

Myocarditis, a severe inflammatory disease, is becoming a worldwide public health concern. This study aims to elucidate the effect of Chemokine (C C motif) receptor-like 2 (CCRL2) in experimental autoimmune myocarditis (EAM) occurrence and its potential regulatory mechanisms.EAM was simulated in a mouse model injected with α-myosin-heavy chain. The changes on EAM were assessed through histological staining of heart tissues, including measuring cardiac troponin I (cTnI), proinflammatory cytokines, transferase-mediated dUTP nick end labeling (TUNEL) assay, and cardiac function. Then, the heart tissues from the EAM mouse model and control groups were analyzed through transcriptome sequencing to identify the differential expressed genes (DEGs) and hub genes related to pyroptosis. Downregulation of CCRL2 further verified the function of CCRL2 on EAM and p21-activated kinase 1/NOD-like receptor protein 3 (PAK/NLRP3) signaling pathways in vivo.The EAM model was constructed successfully, with the heart weight/body weight ratio, serum level of cTnI, and concentrations of proinflammatory cytokines elevation. Moreover, cell apoptosis was also significantly increased. Transcriptome sequencing revealed 696 and 120 upregulated and downregulated DEGs, respectively. After functional enrichment, CCRL2 was selected as a potential target. Then, we verified that CCRL2 knockdown improved cardiac function, alleviated EAM occurrence, and reduced PAK/NLRP3 protein expression.CCRL2 may act as a novel potential treatment target in EAM by regulating the PAK1/NLRP3 pathway.

Stimulation of Formyl Peptide Receptor-2 by the New Agonist CMC23 Protects against Endotoxin-Induced Neuroinflammatory Response: A Study in Organotypic Hippocampal Cultures

A substantial body of evidence demonstrates an association between a malfunction in the resolution of acute inflammation and the development of chronic inflammation. Recently, in this context, the importance of formyl peptide receptor 2 (FPR2) has been underlined. FPR2 activity is modulated by a wide range of endogenous ligands, including specialized pro-resolving mediators (SPMs) (e.g., LXA4 and AT-LXA4) and synthetic ligands. Since SPMs have unfavorable pharmacokinetic properties, we aimed to evaluate the protective and pro-resolving effects of a new potent FPR2 agonist, compound CMC23, in organotypic hippocampal cultures (OHCs) stimulated with lipopolysaccharide (LPS). The protective activity of CMC23 limited the lactate dehydrogenase release in LPS-stimulated cultures. This activity was mediated by the interaction with FPR2 as pretreatment with the FPR2 selective antagonist WRW4 abolished CMC23-induced protection. Furthermore, decreased levels of pro-inflammatory IL-1β and IL-6 were observed after CMC23 administration in LPS-treated OHCs. CMC23 also diminished the LPS-induced increase in IL-17A and both IL-23 subunits p19 and p40 in OHCs. Finally, we demonstrated that CMC23 exerts its beneficial impact via the STAT3/SOCS3 signaling pathway since it attenuated the level of phospho-STAT3 and maintained the LPS-induced SOCS3 levels in OHCs. Collectively, our research implies that the new FPR2 agonist CMC23 has beneficial protective and anti-inflammatory properties in nanomolar doses and FPR2 represents a promising target for the enhancement of inflammation resolution.

Regulation of the JAK/STAT signaling pathway: The promising targets for cardiovascular disease

Individuals have known that Janus kinase (JAK) signal transducer and activator of transcription (STAT) signaling pathway was involved in the growth of the cell, cell differentiation courses advancement, immune cellular survival, as well as hematopoietic system advancement. Researches in the animal models have already uncovered a JAK/STAT regulatory function in myocardial ischemia-reperfusion injury (MIRI), acute myocardial infarction (MI), hypertension, myocarditis, heart failure, angiogenesis and fibrosis. Evidences originating in these studies indicate a therapeutic JAK/STAT function in cardiovascular diseases (CVDs). In this retrospection, various JAK/STAT functions in the normal and ill hearts were described. Moreover, the latest figures about JAK/STAT were summarized under the background of CVDs. Finally, we discussed the clinical transformation prospects and technical limitations of JAK/STAT as the potential therapeutic targets for CVDs. This collection of evidences has essential meanings for the clinical application of JAK/STAT as medicinal agents for CVDs. In this retrospection, various JAK/STAT functions in the normal and ill hearts were described. Moreover, the latest figures about JAK/STAT were summarized under the background of CVDs. Finally, we discussed the clinical transformation prospects and toxicity of JAK/STAT inhibitors as potential therapeutic targets for CVDs. This collection of evidences has essential meanings for the clinical application of JAK/STAT as medicinal agents for CVDs.

Electrical, structural, and autonomic atrial remodeling underlies atrial fibrillation in inflammatory atrial cardiomyopathy

Background

There is growing evidence indicating a close relationship between inflammation and atrial fibrillation (AF). Although underlying inflammatory atrial cardiomyopathy may contribute to the development of AF, the arrhythmogenic remodeling caused by atrial inflammation has not been elucidated in detail. Herein, we examined electrical, structural, and autonomic changes in the atria in a mouse model of autoimmune myocarditis.

Methods

BALB/c mice were immunized with cardiac myosin peptide (MyHC-α_614-629) conjugated with complete Freund's adjuvant on days 0 and 7. Susceptibility to AF was assessed using right-atrial burst pacing.

Results

The mice immunized with MyHC-α_614-629 showed an inflammatory atrial cardiomyopathy phenotype, with enlarged atria; a high degree of inflammatory cell infiltration primarily consisting of CD4⁺ T cells, CD8⁺ T cells, Ly6G^lowCD11b⁺ macrophages, and CD11c⁺ dendritic cells; and severe interstitial fibrosis with collagen deposition. These mice demonstrated significantly enhanced susceptibility to AF, as indicated by their increased AF induction rate and duration. In addition, the expression of potassium channels (Kcnh2, Kcnd3, and Kcnj2) and calcium handling-associated genes (Cacna1c, Camk2, Ryr2, and Atp2a2) was downregulated. Connexin 40 expression was significantly downregulated, leading to frequent lateralization to the inflamed atrium. Sympathetic and parasympathetic innervation and neurotrophin expression (nerve growth factor and brain-derived neurotrophic factor) were upregulated in the inflamed atria.

Conclusion

Inflammatory atrial cardiomyopathy promotes susceptibility to AF via arrhythmogenic electrical, structural, and autonomic remodeling of the atria.

HMG-CoA Reductase Inhibitor, Simvastatin Is Effective in Decreasing Degree of Myocarditis by Inhibiting Metalloproteinases Activation

Background: Acute myocarditis often progresses to heart failure because there is no effective, etiology-targeted therapy of this disease. Simvastatin has been shown to be cardioprotective by decreasing matrix metalloproteinases’ (MMPs) activity. The study was designed to determine whether simvastatin inhibits MMPs activity, decreases the severity of inflammation and contractile dysfunction of the heart in experimental autoimmune myocarditis (EAM). Methods: Simvastatin (3 or 30 mg/kg/day) was given to experimental rats with EAM by gastric gavage for 21 days. Then transthoracic echocardiography was performed, MMPs activity and troponin I level were determined and tissue samples were assessed under a light and transmission electron microscope. Results: Hearts treated with simvastatin did not show left ventricular enlargement. As a result of EAM, there was an enhanced activation of MMP-9, which was significantly reduced in the high-dose simvastatin group compared to the low-dose group. It was accompanied by prevention of myofilaments degradation and reduction of severity of inflammation. Conclusions: The cardioprotective effects of simvastatin in the acute phase of EAM are, at least in part, due to its ability to decrease MMP-9 activity and subsequent decline in myofilaments degradation and suppression of inflammation. These effects were achieved in doses equivalent to therapeutic doses in humans.

Attenuation of Experimental Autoimmune Uveitis in Lewis Rats by Betaine

Experimental autoimmune uveitis (EAU) is an animal model of human autoimmune uveitis that is characterized by the infiltration of autoimmune T cells with concurrent increases in pro-inflammatory cytokines and reactive oxygen species. This study aimed to assess whether betaine regulates the progression of EAU in Lewis rats. EAU was induced via immunization with the interphotoreceptor retinoid-binding protein (IRBP) and oral administration of either a vehicle or betaine (100 mg/kg) for 9 consecutive days. Spleens, blood, and retinas were sampled from the experimental rats at the time of sacrifice and used for the T cell proliferation assay, serological analysis, real-time polymerase chain reaction, and immunohistochemistry. The T cell proliferation assay revealed that betaine had little effect on the proliferation of splenic T cells against the IRBP antigen in an in vitro assay on day 9 post-immunization. The serological analysis showed that the level of serum superoxide dismutase increased in the betaine-treated group compared with that in the vehicle-treated group. The anti-inflammatory effect of betaine was confirmed by the downregulation of pro-inflammation-related molecules, including vascular cell adhesion molecule 1 and interleukin-1β in the retinas of rats with EAU. The histopathological findings agreed with those of ionized calcium-binding adaptor molecule 1 immunohistochemistry, further verifying that inflammation in the retina and ciliary bodies was significantly suppressed in the betaine-treated group compared with the vehicle-treated group. Results of the present study suggest that betaine is involved in mitigating EAU through anti-oxidation and anti-inflammatory activities.

Clinical significance of chronic myocarditis: systematic review and meta-analysis

Chronic myocarditis is a prolonged inflammatory condition in the myocardium and its histological manifestation is defined by the presence of an inflammatory infiltrate. Chronic myocarditis has not been well known and its treatment of chronic myocarditis has not been established. Primary outcome of this study was to assess the efficacy of immunomodulatory treatment in addition to conventional treatment, and secondary outcomes were to clarity the prognosis of natural history of chronic myocarditis and incidence of chronic myocarditis in patients with dilated cardiomyopathy (DCM). We searched for studies in Medline, Embase, Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi published between January 1946 and June 2020. Sixteen studies met the inclusion criteria. A meta-analysis revealed that patients receiving immunomodulatory treatment showed an improvement in left ventricular ejection fraction after immunomodulatory treatment compared to the control group (hazard ratio, 16.65; confidence interval, 4.55-28.74; p = 0.007). Five-year survival rate of the patients with inflammatory DCM (iDCM) and DCM was 52.7-70.3% and 51.9-91.1%, respectively. Moreover, 51.5%-62.7% of patients with DCM met the criteria of iDCM. Our systematic review revealed that patients with chronic myocarditis had poor prognosis and immunomodulatory treatment was significantly effective in addition to conventional treatment.

Pitavastatin Is a Highly Potent Inhibitor of T-Cell Proliferation

Repositioning of approved drugs is an alternative time- and cost-saving strategy to classical drug development. Statins are 3-hydroxy-3-methylglutaryl-CoA (HMG CoA) reductase inhibitors that are usually used as cholesterol-lowering medication, and they also exhibit anti-inflammatory effects. In the present study, we observed that the addition of Pitavastatin at nanomolar concentrations inhibits the proliferation of CD3/CD28 antibody-stimulated human T cells of healthy donors in a dose-dependent fashion. The 50% inhibition of proliferation (IC50) were 3.6 and 48.5 nM for freshly stimulated and pre-activated T cells, respectively. In addition, Pitavastatin suppressed the IL-10 and IL-17 production of stimulated T cells. Mechanistically, we found that treatment of T cells with doses <1 µM of Pitavastatin induced hyperphosphorylation of ERK1/2, and activation of caspase-9, -3 and -7, thus leading to apoptosis. Mevalonic acid, cholesterol and the MEK1/2 inhibitor U0126 reversed this Pitavastatin-mediated ERK1/2 activation and apoptosis of T cells. In summary, our results suggest that Pitavastatin is a highly potent inhibitor of T-cell proliferation, which induces apoptosis via pro-apoptotic ERK1/2 activation, thus representing a potential repositioning candidate for the treatment of T-cell-mediated autoimmune diseases.

Effects of statins on myocarditis: A review of underlying molecular mechanisms

Myocarditis refers to the clinical and histological characteristics of a diverse range of inflammatory cellular pathophysiological conditions which result in cardiac dysfunction. Myocarditis is a major cause of mortality in individuals less than 40 years of age and accounts for approximately 20% of cardiovascular disease (CVD) events. Myocarditis contributes to dilated cardiomyopathy in 30% of patients and can progress to cardiac arrest, which has a poor prognosis of <40% survival over 10 years. Myocarditis has also been documented after infection with SARS-CoV-2. The most commonly used lipid-lowering therapies, HMG-CoA reductase inhibitors (statins), decrease CVD-related morbidity and mortality. In addition to their lipid-lowering effects, increasing evidence supports the existence of several additional beneficial, 'pleiotropic' effects of statins. Recently, several studies have indicated that statins may attenuate myocarditis. Statins modify the lipid oxidation, inflammation, immunomodulation, and endothelial activity of the pathophysiology and have been recommended as adjuvant treatment. In this review, we focus on the mechanisms of action of statins and their effects on myocarditis, SARS-CoV-2 and CVD.

Key Enzymes for the Mevalonate Pathway in the Cardiovascular System

ABSTRACT

Isoprenylation is an important post-transcriptional modification of small GTPases required for their activation and function. Isoprenoids, including farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate, are indispensable for isoprenylation by serving as donors of a prenyl moiety to small G proteins. In the human body, isoprenoids are mainly generated by the mevalonate pathway (also known as the cholesterol-synthesis pathway). The hydroxymethylglutaryl coenzyme A reductase catalyzes the first rate-limiting steps of the mevalonate pathway, and its inhibitor (statins) are widely used as lipid-lowering agents. In addition, the FPP synthase is also of critical importance for the regulation of the isoprenoids production, for which the inhibitor is mainly used in the treatment of osteoporosis. Synthetic FPP can be further used to generate geranylgeranyl pyrophosphate and cholesterol. Recent studies suggest a role for isoprenoids in the genesis and development of cardiovascular disorders, such as pathological cardiac hypertrophy, fibrosis, endothelial dysfunction, and fibrotic responses of smooth-muscle cells. Furthermore, statins and FPP synthase inhibitors have also been applied for the management of heart failure and other cardiovascular diseases rather than their clinical use for hyperlipidemia or bone diseases. In this review, we focus on the function of several critical enzymes, including hydroxymethylglutaryl coenzyme A reductase, FPP synthase, farnesyltransferase, and geranylgeranyltransferase in the mevalonate pathway which are involved in regulating the generation of isoprenoids and isoprenylation of small GTPases, and their pathophysiological role in the cardiovascular system. Moreover, we summarize recent research into applications of statins and the FPP synthase inhibitors to treat cardiovascular diseases, rather than for their traditional indications respectively.

Programmed Death-Ligand 2 Deficiency Exacerbates Experimental Autoimmune Myocarditis in Mice

Programmed death ligand 2 (PD-L2) is the second ligand of programmed death 1 (PD-1) protein. In autoimmune myocarditis, the protective roles of PD-1 and its first ligand programmed death ligand 1 (PD-L1) have been well documented; however, the role of PD-L2 remains unknown. In this study, we report that PD-L2 deficiency exacerbates myocardial inflammation in mice with experimental autoimmune myocarditis (EAM). EAM was established in wild-type (WT) and PD-L2-deficient mice by immunization with murine cardiac myosin peptide. We found that PD-L2-deficient mice had more serious inflammatory infiltration in the heart and a significantly higher myocarditis severity score than WT mice. PD-L2-deficient dendritic cells (DCs) enhanced CD4⁺ T cell proliferation in the presence of T cell receptor and CD28 signaling. These data suggest that PD-L2 on DCs protects against autoreactive CD4⁺ T cell expansion and severe inflammation in mice with EAM.

A New Mouse Model of Chronic Myocarditis Induced by Recombinant Bacille Calmette-Guèrin Expressing a T-Cell Epitope of Cardiac Myosin Heavy Chain-α

Dilated cardiomyopathy (DCM) is a potentially lethal disorder characterized by progressive impairment of cardiac function. Chronic myocarditis has long been hypothesized to be one of the causes of DCM. However, owing to the lack of suitable animal models of chronic myocarditis, its pathophysiology remains unclear. Here, we report a novel mouse model of chronic myocarditis induced by recombinant bacille Calmette-Guérin (rBCG) expressing a CD4+ T-cell epitope of cardiac myosin heavy chain-α (rBCG-MyHCα). Mice immunized with rBCG-MyHCα developed chronic myocarditis, and echocardiography revealed dilation and impaired contraction of ventricles, similar to those observed in human DCM. In the heart, CD62L-CD4+ T cells were increased and produced significant amounts of IFN-γ and IL-17 in response to cardiac myosin. Adoptive transfer of CD62L-CD4+ T cells induced myocarditis in the recipient mice, which indicated that CD62L-CD4+ T cells were the effector cells in this model. rBCG-MyHCα-infected dendritic cells produced proinflammatory cytokines and induced MyHCα-specific T-cell proliferation and Th1 and Th17 polarization. This novel chronic myocarditis mouse model may allow the identification of the central pathophysiological and immunological processes involved in the progression to DCM.

Cardiac apoptosis caused by elevated cholesterol level in experimental autoimmune myocarditis

It has been reported that cholesterol-lowing agents can ameliorate severity of myocarditis. However, the beneficial effect of the agents has been claimed to be independent of cholesterol reduction as there is no significant change in the plasma cholesterol level in myocarditis. In the present study, using experimental autoimmune myocarditis (EAM) rats as an animal model, we demonstrated that EAM induced elevation of cholesterol level and impaired cholesterol efflux capacity in the cardiac tissue. Moreover, serum high-density lipoprotein (HDL) content was reduced and HDL function associated protein Paraoxonase 1 (PON1) activity was decreased. Besides, the major structural protein within HDL, Apolipoprotein A1 (ApoA1) expression in the cardiac tissues was significantly reduced while the level of serum ApoA1 was not significantly altered. Importantly, cholesterol depleting agent methyl-β-cyclodextrin (MβCD) alleviated the development of EAM, as monitored by decreased ratio of heart weight to body weight (HW/BW), decreased infiltration of inflammatory cells and collagen deposition, improved cardiac function, reduced expression of apoptosis-related protein Bax, Fas, FasL and caspase-3 and increased level of anti-apoptotic protein Bcl-2. These results suggest that reduction of cholesterol level in cardiac tissue could suppress EAM-induced cardiac apoptosis through both intrinsic and extrinsic apoptotic pathways.

Pitavastatin Exerts Potent Anti-Inflammatory and Immunomodulatory Effects via the Suppression of AP-1 Signal Transduction in Human T Cells

Statins inhibiting 3-hydroxy-3-methylglutaryl-CoA reductase are the standard treatment for hypercholesterolemia in atherosclerotic cardiovascular disease (ASCVD), mediated by inflammatory reactions within vessel walls. Several studies highlighted the pleiotropic effects of statins beyond their lipid-lowering properties. However, few studies investigated the effects of statins on T cell activation. This study evaluated the immunomodulatory capacities of three common statins, pitavastatin, atorvastatin, and rosuvastatin, in activated human T cells. The enzyme-linked immunosorbent assay (ELISA) and quantitative real time polymerase chain reaction (qRT-PCR) results demonstrated stronger inhibitory effects of pitavastatin on the cytokine production of T cells activated by phorbol 12-myristate 13-acetate (PMA) plus ionomycin, including interleukin (IL)-2, interferon (IFN)-γ, IL-6, and tumor necrosis factor α (TNF-α). Molecular investigations revealed that pitavastatin reduced both activating protein-1 (AP-1) DNA binding and transcriptional activities. Further exploration showed the selectively inhibitory effect of pitavastatin on the signaling pathways of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), but not c-Jun N-terminal kinase (JNK). Our findings suggested that pitavastatin might provide additional benefits for treating hypercholesterolemia and ASCVD through its potent immunomodulatory effects on the suppression of ERK/p38/AP-1 signaling in human T cells.

Biocatalyzed Synthesis of Statins: A Sustainable Strategy for the Preparation of Valuable Drugs

Statins, inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, are the largest selling class of drugs prescribed for the pharmacological treatment of hypercholesterolemia and dyslipidaemia. Statins also possess other therapeutic effects, called pleiotropic, because the blockade of the conversion of HMG-CoA to (R)-mevalonate produces a concomitant inhibition of the biosynthesis of numerous isoprenoid metabolites (e.g., geranylgeranyl pyrophosphate (GGPP) or farnesyl pyrophosphate (FPP)). Thus, the prenylation of several cell signalling proteins (small GTPase family members: Ras, Rac, and Rho) is hampered, so that these molecular switches, controlling multiple pathways and cell functions (maintenance of cell shape, motility, factor secretion, differentiation, and proliferation) are regulated, leading to beneficial effects in cardiovascular health, regulation of the immune system, anti-inflammatory and immunosuppressive properties, prevention and treatment of sepsis, treatment of autoimmune diseases, osteoporosis, kidney and neurological disorders, or even in cancer therapy. Thus, there is a growing interest in developing more sustainable protocols for preparation of statins, and the introduction of biocatalyzed steps into the synthetic pathways is highly advantageous—synthetic routes are conducted under mild reaction conditions, at ambient temperature, and can use water as a reaction medium in many cases. Furthermore, their high selectivity avoids the need for functional group activation and protection/deprotection steps usually required in traditional organic synthesis. Therefore, biocatalysis provides shorter processes, produces less waste, and reduces manufacturing costs and environmental impact. In this review, we will comment on the pleiotropic effects of statins and will illustrate some biotransformations nowadays implemented for statin synthesis.

Immunotropic Effects and Proposed Mechanism of Action for 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase Inhibitors (Statins)

Inhibitors of HMG-CoA reductase (statins) are the major group of lipid-lowering drugs. Along with hypocholesterolemic activity, statins exhibit anti-inflammatory and immunomodulatory properties that expand their clinical use, particularly, in the treatment of chronic inflammatory and autoimmune disorders. In this review, we critically analyze the data of statin effects on immune cells (e.g., monocytes and T cells) involved in the development of atherosclerosis and other chronic inflammatory diseases. We (i) discuss the properties of statins and routes of cell entry, as well as their major intracellular targets; (ii) evaluate the data on the effects of statins on the subset composition of circulatory monocytes, ability of monocytes to migrate to the site of inflammation (cell motility and expression of adhesion molecules and chemokine receptors), production of cytokines, matrix metalloproteinases, and reactive oxygen species by monocytes/macrophages, and antigen-presenting activity in peripheral blood monocyte-derived dendritic cells; and (iii) summarize the data on the regulation of proliferation and differentiation of various CD4+ T cell subsets (type 1/2/17 helper T cells and regulatory T cells) by statins.

Alopecia Areata: Review of Epidemiology, Clinical Features, Pathogenesis, and New Treatment Options

Alopecia areata (AA) is a complex autoimmune condition that causes nonscarring hair loss. It typically presents with sharply demarcated round patches of hair loss and may present at any age. In this article, we review the epidemiology, clinical features, pathogenesis, and new treatment options of AA, with a focus on the immunologic mechanism underlying the treatment. While traditional treatment options such as corticosteroids are moderately effective, a better understanding of the disease pathogenesis may lead to the development of new treatments that are more directed and effective against AA. Sources were gathered from PubMed, Embase, and the Cochrane database using the keywords: alopecia, alopecia areata, hair loss, trichoscopy, treatments, pathogenesis, and epidemiology.

Effect of butylphthalide intervention on experimental autoimmune myositis in guinea pigs

Idiopathic inflammatory myopathies are a group of rare muscular diseases that are characterized by acute, subacute or chronic proximal and symmetric muscle weakness, muscle fiber necrosis and infiltration of inflammatory cells, particularly activated CD8⁺ cytotoxic T cells and phagocytes. 3-n-butylphthalide (NBP) protects mitochondria and reduces the inflammatory response in multiple disease models. In myositis, it has remained elusive whether NBP can protect muscle cells from muscle fiber injury. Experimental autoimmune myositis (EAM) was induced in a total of 40 guinea pigs by myosin immunization. After 4 weeks, low- or high-dose NBP solution was intraperitoneally injected. Saline solution was used as a negative control. After 10 days, the clinical manifestations were assessed by determining rodent grasping power, histopathological changes, Ca²⁺-adenosinetriphosphatase (ATPase) activity by an ATPase kit, and mRNA expression of interferon (IFN)-γ, retinoic acid receptor-related orphan nuclear receptor (ROR)γt and forkhead box (Fox) p3 in muscle tissue by reverse-transcription quantitative polymerase chain reaction analysis. It was demonstrated that NBP improved the myodynamia of guinea pigs with EAM and reduced the pathological inflammatory cell infiltration in a dose-dependent manner. NBP improved the Ca²⁺-ATPase activity of the muscle mitochondrial membrane and muscle plasma membrane in animals with EAM. It also reduced the mRNA expression of IFN-γ and RORγt, and significantly increased the mRNA expression of Foxp3 in muscle tissue. These results provided a basis for the consideration of NBP as a novel agent for the treatment of myositis and other muscular diseases associated with autoimmunity and inflammation.

Anti-asthmatic effect of pitavastatin through aerosol inhalation is associated with CD4+ CD25+ Foxp3+ T cells in an asthma mouse model

Statins are competitive inhibitors of 3-hydroxy-3-methylglutaryl-CoA (HMG-A) reductase, and studies have shown that statins also have anti-inflammatory and immunomodulatory properties. The purpose of this study was to investigate the anti-asthmatic effects of pitavastatin, a type of statin, in an asthma mouse model. Mice were sensitized and challenged with ovalbumin (OVA) to establish the asthma model. These mice were then treated with inhaled pitavastatin (5 mg/kg) or dexamethasone (2 mg/kg), the latter of which served as a positive control. The results of the study showed that pitavastatin reduced allergen-induced increases in airway resistance and alleviated bronchial tube thickness and goblet cell hyperplasia in lung tissues. In addition, the results showed that pitavastatin inhibited OVA-induced increases in eosinophil counts and total inflammatory cell counts in bronchoalveolar lavage fluid (BALF) and increased the percentage of CD4+ CD25+ Foxp3+ Treg in the BALF of asthmatic mice. IL-4 and IL-17 levels were decreased, whereas IFN-γ levels were significantly increased in the BALF of pitavastatin-treated mice compared with the BALF of OVA-challenged mice. These results suggest that pitavastatin has potential as a therapy for allergic airway disease and that its effects are associated with its ability to regulate CD4+ CD25+ Foxp3+ T cell counts.

Anandamide attenuates Th-17 cell-mediated delayed-type hypersensitivity response by triggering IL-10 production and consequent microRNA induction

Endogenous cannabinoids [endocannabinoids] are lipid signaling molecules that have been shown to modulate immune functions. However, their role in the regulation of Th17 cells has not been studied previously. In the current study, we used methylated Bovine Serum Albumin [mBSA]-induced delayed type hypersensitivity [DTH] response in C57BL/6 mice, mediated by Th17 cells, as a model to test the anti-inflammatory effects of endocannabinoids. Administration of anandamide [AEA], a member of the endocannabinoid family, into mice resulted in significant mitigation of mBSA-induced inflammation, including foot pad swelling, cell infiltration, and cell proliferation in the draining lymph nodes [LN]. AEA treatment significantly reduced IL-17 and IFN-γ production, as well as decreased RORγt expression while causing significant induction of IL-10 in the draining LNs. IL-10 was critical for the AEA-induced mitigation of DTH response inasmuch as neutralization of IL-10 reversed the effects of AEA. We next analyzed miRNA from the LN cells and found that 100 out of 609 miRNA species were differentially regulated in AEA-treated mice when compared to controls. Several of these miRNAs targeted proinflammatory mediators. Interestingly, many of these miRNA were also upregulated upon in vitro treatment of LN cells with IL-10. Together, the current study demonstrates that AEA may suppress Th-17 cell–mediated DTH response by inducing IL-10 which in turn triggers miRNA that target proinflammatory pathways.

Involvement of peptidyl-prolyl isomerase Pin1 in the inhibitory effect of fluvastatin on endothelin-1-induced cardiomyocyte hypertrophy

AIMS

Cardiac hypertrophy is elicited by endothelin (ET)-1 as well as other neurohumoral factors, hemodynamic overload, and oxidative stress; HMG-CoA reductase inhibitors (statins) were shown to inhibit cardiac hypertrophy partly via the anti-oxidative stress. One of their common intracellular pathways is the phosphorylation cascade of MEK signaling. Pin1 specifically isomerizes the phosphorylated protein with Ser/Thr-Pro bonds and regulates their activity through conformational changes. There is no report whether the Pin1 activation contributes to ET-1-induced cardiomyocyte hypertrophy and whether the Pin1 inactivation contributes to the inhibitory effect of statins. The aim of this study was to reveal these questions.

MAIN METHODS

We assessed neonatal rat cardiomyocyte hypertrophy using ET-1 and fluvastatin by the cell surface area, ANP mRNA expression, JNK and c-Jun phosphorylation, and [(3)H]-leucine incorporation.

KEY FINDINGS

Fluvastatin inhibited ET-1-induced increase in the cell surface area, ANP expression, and [(3)H]-leucine incorporation; and it suppressed the signaling cascade from JNK to c-Jun. The phosphorylated Pin1 level, an inactive form, was decreased by ET-1; however, it reached basal level by fluvastatin. Furthermore, Pin1 overexpression clearly elicited cardiomyocyte hypertrophy, which was inhibited by fluvastatin.

SIGNIFICANCE

This is the first report that ET-1-induced cardiomyocyte hypertrophy is mediated through the Pin1 activation and that the inhibitory effect of fluvastatin on cardiomyocyte hypertrophy would partly be attributed to the suppression of the Pin1 function. This study firstly suggests that Pin1 determines the size of hypertrophied cardiomyocyte by regulating the activity of phosphorylated molecules and that statins exert their pleiotropic effects partly via Pin1 inactivation.

Endothelin receptor antagonist exacerbates autoimmune myocarditis in mice

AIMS

Myocarditis and subsequent dilated cardiomyopathy are major causes of heart failure in young adults. Experimental autoimmune myocarditis (EAM) is a mouse model of post-infectious myocarditis and inflammatory cardiomyopathy. The pathological role of endothelin (ET) in myocarditis has not been elucidated.

MAIN METHODS

EAM was induced by immunization of cardiac myosin peptide with complete Freund's adjuvant on days 0 and 7 in BALB/c mice. An ETA/ETB dual receptor antagonist, SB209670, was administered by a continuous infusion from a subcutaneous pump for 2 weeks.

KEY FINDINGS

An increase in the heart-to-body weight ratio was observed in SB209670-treated mice compared with vehicle-treated mice. Heart pathology in SB209670-treated mice was remarkable for gross inflammatory infiltration, in contrast to the lesser inflammation in the hearts of vehicle-treated mice. We found that an ET blockade decreased the number of Foxp3(+) regulatory T cells in the heart. The ET blockade also inhibited the expression of the suppressor of cytokine signaling 3 that plays a key role in the negative regulation of both Toll-like receptor- and cytokine receptor-mediated signaling. EAM is a CD4(+) T cell-mediated disease. CD4(+) T cells isolated from SB209670-treated EAM mice produced less IL-10 and more inflammatory cytokines, IL-6 and IL-17, than those isolated from vehicle-treated mice.

SIGNIFICANCE

The ET receptor antagonist exacerbated autoimmune myocarditis in mice. Our novel findings suggest that ET may play an important role in the regulation of inflammation in myocarditis.