Rosuvastatin Attenuates Progression of Atherosclerosis and Reduces Serum IL6 and CCL2 Levels in Apolipoprotein-E-deficient Mice

BACKGROUND/AIM

Apolipoprotein E-deficient (Apoe^-/-) mice develop atherosclerotic lesions that closely resemble metabolic syndrome in humans. We sought to investigate how rosuvastatin mitigates the atherosclerotic profile of Apoe^-/- mice over time and its effects on certain inflammatory chemokines.

MATERIALS AND METHODS

Eighteen Apoe^-/- mice were allocated into three groups of six mice each receiving: standard chow diet (SCD; control group); high-fat diet (HFD); and HFD and rosuvastatin at 5 mg/kg/d orally via gavage for 20 weeks. Analysis of aortic plaques and lipid deposition was conducted by means of en face Sudan IV staining and Oil Red O staining. Serum cholesterol, low-density lipoprotein, high-density lipoprotein, plasma glucose and triglyceride levels were determined at baseline and after 20 weeks of treatment. Serum interleukin 6 (IL6), C-C motif chemokine ligand 2 (CCL2) and tumor necrosis factor-α (TNFα) levels were measured by enzyme-linked immunosorbent assay at the time of euthanasia.

RESULTS

The lipidemic profile of Apoe^-/- mice on HFD deteriorated over time. Apoe^-/- mice on HFD developed atherosclerotic lesions over time. Sudan IV and Oil Red O-stained sections of the aorta revealed increased plaque formation and plaque lipid deposition in HFD-fed mice compared with SCD-fed mice and reduced plaque development in HFD-fed mice treated with rosuvastatin compared with mice not receiving statin treatment. Serum analysis revealed reduced metabolic parameters in HFD-fed mice on rosuvastatin compared with non-statin, HFD-fed mice. At the time of euthanasia, HFD-fed mice treated with rosuvastatin had significantly lower IL6 as well as CCL2 levels when compared with HFD-fed mice not receiving rosuvastatin. TNFα levels were comparable among all groups of mice, irrespective of treatment. IL6 and CCL2 positively correlated with the extent of atherosclerotic lesions and lipid deposition in atherosclerotic plaques.

CONCLUSION

Serum IL6 and CCL2 levels might potentially be used as clinical markers of progression of atherosclerosis during statin treatment for hypercholesterolemia.

CD103 integrin identifies a high IL-10-producing FoxP3+ regulatory T-cell population suppressing allergic airway inflammation

BACKGROUND

Although FoxP3⁺ regulatory T (Treg) cells constitute a highly heterogeneous population, with different regulatory potential depending on the disease context, distinct subsets or phenotypes remain poorly defined. This hampers the development of immunotherapy for allergic and autoimmune disorders. The present study aimed at characterizing distinct FoxP3⁺ Treg subpopulations involved in the suppression of Th2-mediated allergic inflammation in the lung.

METHODS

We used an established mouse model of allergic airway disease based on ovalbumin sensitization and challenge to analyze FoxP3⁺ Tregs during the induction and resolution of inflammation, and identify markers that distinguish their most suppressive phenotypes. We also developed a new knock-in mouse model (Foxp3^cre Cd103^dtr ) enabling the specific ablation of CD103⁺ FoxP3⁺ Tregs for functional studies.

RESULTS

We found that during resolution of allergic airway inflammation in mice >50% of FoxP3⁺ Treg cells expressed the integrin CD103 which marks FoxP3⁺ Treg cells of high IL-10 production, increased expression of immunoregulatory molecules such as KLRG1, ICOS and CD127, and enhanced suppressive capacity for Th2-mediated inflammatory responses. CD103⁺ FoxP3⁺ Tregs were essential for keeping allergic inflammation under control as their specific depletion in Foxp3^cre Cd103^dtr mice lead to severe alveocapillary damage, eosinophilic pneumonia, and markedly reduced lifespan of the animals. Conversely, adoptive transfer of CD103⁺ FoxP3⁺ Tregs effectively treated disease, attenuating Th2 responses and allergic inflammation in an IL-10-dependent manner.

CONCLUSIONS

Our study identifies a novel regulatory T-cell population, defined by CD103 expression, programmed to prevent exuberant type 2 inflammation and keep homeostasis in the respiratory tract under control. This has important therapeutic implications.

The TAXINOMISIS Project: A multidisciplinary approach for the development of a new risk stratification model for patients with asymptomatic carotid artery stenosis

INTRODUCTION

Asymptomatic carotid artery stenosis (ACAS) may cause future stroke and therefore patients with ACAS require best medical treatment. Patients at high risk for stroke may opt for additional revascularization (either surgery or stenting) but the future stroke risk should outweigh the risk for peri/post-operative stroke/death. Current risk stratification for patients with ACAS is largely based on outdated randomized-controlled trials that lack the integration of improved medical therapies and risk factor control. Furthermore, recent circulating and imaging biomarkers for stroke have never been included in a risk stratification model. The TAXINOMISIS Project aims to develop a new risk stratification model for cerebrovascular complications in patients with ACAS and this will be tested through a prospective observational multicentre clinical trial performed in six major European vascular surgery centres.

METHODS AND ANALYSIS

The risk stratification model will compromise clinical, circulating, plaque and imaging biomarkers. The prospective multicentre observational study will include 300 patients with 50%-99% ACAS. The primary endpoint is the three-year incidence of cerebrovascular complications. Biomarkers will be retrieved from plasma samples, brain MRI, carotid MRA and duplex ultrasound. The TAXINOMISIS Project will serve as a platform for the development of new computer tools that assess plaque progression based on radiology images and a lab-on-chip with genetic variants that could predict medication response in individual patients.

CONCLUSION

Results from the TAXINOMISIS study could potentially improve future risk stratification in patients with ACAS to assist personalized evidence-based treatment decision-making.

Iron restriction inside macrophages regulates pulmonary host defense against Rhizopus species

Mucormycosis is a life-threatening respiratory fungal infection predominantly caused by Rhizopus species. Mucormycosis has incompletely understood pathogenesis, particularly how abnormalities in iron metabolism compromise immune responses. Here we show how, as opposed to other filamentous fungi, Rhizopus spp. establish intracellular persistence inside alveolar macrophages (AMs). Mechanistically, lack of intracellular swelling of Rhizopus conidia results in surface retention of melanin, which induces phagosome maturation arrest through inhibition of LC3-associated phagocytosis. Intracellular inhibition of Rhizopus is an important effector mechanism, as infection of immunocompetent mice with swollen conidia, which evade phagocytosis, results in acute lethality. Concordantly, AM depletion markedly increases susceptibility to mucormycosis. Host and pathogen transcriptomics, iron supplementation studies, and genetic manipulation of iron assimilation of fungal pathways demonstrate that iron restriction inside macrophages regulates immunity against Rhizopus. Our findings shed light on the pathogenetic mechanisms of mucormycosis and reveal the role of macrophage-mediated nutritional immunity against filamentous fungi.

Mucormycosis is a life-threatening respiratory fungal infection that typically occurs in patients with abnormalities in iron metabolism. Here the authors show that iron restriction inside the phagosome of macrophages is an essential component of the host defense against Rhizopus, the main species causing mucormycosis.

Conditional inactivation of nicastrin restricts amyloid deposition in an Alzheimer's disease mouse model

Production of Aβ by γ-secretase is a key event in Alzheimer's disease (AD). The γ-secretase complex consists of presenilin (PS) 1 or 2, nicastrin (ncstn), Pen-2, and Aph-1 and cleaves type I transmembrane proteins, including the amyloid precursor protein (APP). Although ncstn is widely accepted as an essential component of the complex required for γ-secretase activity, recent in vitro studies have suggested that ncstn is dispensable for APP processing and Aβ production. The focus of this study was to answer this controversy and evaluate the role of ncstn in Aβ generation and the development of the amyloid-related phenotype in the mouse brain. To eliminate ncstn expression in the mouse brain, we used a ncstn conditional knockout mouse that we mated with an established AD transgenic mouse model (5XFAD) and a neuronal Cre-expressing transgenic mouse (CamKIIα-iCre), to generate AD mice (5XFAD/CamKIIα-iCre/ncstn(f/f) mice) where ncstn was conditionally inactivated in the brain. 5XFAD/CamKIIα-iCre/ncstn(f/f) mice at 10 week of age developed a neurodegenerative phenotype with a significant reduction in Aβ production and formation of Aβ aggregates and the absence of amyloid plaques. Inactivation of nctsn resulted in substantial accumulation of APP-CTFs and altered PS1 expression. These results reveal a key role for ncstn in modulating Aβ production and amyloid plaque formation in vivo and suggest ncstn as a target in AD therapeutics.