Anti-CXCR2 antibody-coated nanoparticles with an erythrocyte-platelet hybrid membrane layer for atherosclerosis therapy

Atherosclerosis is the leading cause of mortality globally. RBC-platelet hybrid membrane-coated nanoparticles ([RBC-P]NPs), which biologically mimic platelets in vivo, display evidence of anti-atherosclerotic activity. The efficacy of a targeted RBC-platelet hybrid membrane-coated nanoparticles ([RBC-P]NP)-based approach was investigated as a primary preventive measure against atherosclerosis. A ligand-receptor interactome analysis conducted with circulating platelets and monocytes derived from CAD patients and healthy controls identified CXCL8-CXCR2 as a key platelet ligand-monocyte receptor dyad in CAD patients. Based on this analysis, a novel anti-CXCR2 [RBC-P]NP that specifically binds to CXCR2 and blocks the interaction between CXCL8 and CXCR2 was engineered and characterized. Administering anti-CXCR2 [RBC-P]NPs to Western diet-fed Ldlr^-/- mice led to diminished plaque size, necrosis, and intraplaque macrophage accumulation relative to control [RBC-P]NPs or vehicle. Importantly, anti-CXCR2 [RBC-P]NPs demonstrated no adverse bleeding/hemorrhagic effects. A series of in vitro experiments was conducted to characterize anti-CXCR2 [RBC-P]NP's mechanism of action in plaque macrophages. Mechanistically, anti-CXCR2 [RBC-P]NPs inhibited p38α (Mapk14)-mediated, pro-inflammatory M1 skewing and corrected efferocytosis in plaque macrophages. This targeted [RBC-P]NP-based approach, in which the cardioprotective effects of anti-CXCR2 [RBC-P]NP therapy overweighs its bleeding/hemorrhagic risks, could potentially be used to proactively manage atherosclerotic progression in at-risk populations.

Stroke-induced hexokinase 2 in circulating monocytes exacerbates vascular inflammation and atheroprogression

BACKGROUND

Stroke accelerates inflammatory monocyte recruitment to the endothelium and consequent atheroprogression via high-mobility group box 1-receptor for advanced glycation end products (Hmgb1-RAGE) signaling. Notably, Hmgb1 interacts with multiple Toll-like receptors (TLRs) and promotes TLR4-mediated pro-inflammatory myeloid cell activation. Therefore, TLR-associated mechanism(s) within monocytes may play a role in Hmgb1-driven post-stroke atheroprogression.

OBJECTIVES

We aimed to elucidate the TLR-associated mechanism(s) within monocytes that contribute to stroke-induced exacerbation of atherosclerotic disease.

METHODS

A weighted gene co-expression network analysis (WGCNA) on whole blood transcriptomes of stroke model mice identified hexokinase 2 (HK2) as a key gene associated with TLR signaling in ischemic stroke. We conducted a cross-sectional analysis of monocyte hexokinase 2 (HK2) levels in ischemic stroke patients. We performed in vitro and in vivo studies using high-cholesterol diet (HCD)-fed myeloid-specific Hk2-null ApoE^-/- (ApoE^-/-;Hk2^ΔMϕ) mice and ApoE^-/-;Hk2^fl/fl controls.

RESULTS

We found markedly higher monocyte HK2 levels in ischemic stroke patients during the acute and subacute phases post-stroke. Similarly, stroke model mice displayed a profound increase in monocyte Hk2 levels. Using aortas and aortic valve samples collected from HCD-fed ApoE^-/-;Hk2^ΔMϕ mice and ApoE^-/-;Hk2^fl/fl controls, we found that stroke-induced monocyte Hk2 upregulation enhanced post-stroke atheroprogression and inflammatory monocyte recruitment to the endothelium. Stroke-induced monocyte Hk2 upregulation induced inflammatory monocyte activation, systemic inflammation, and atheroprogression via Il-1β. Mechanistically, we demonstrated that stroke-induced monocyte Hk2 upregulation was dependent upon Hmgb1-driven p38-dependent hypoxia-inducible factor 1-alpha (Hif-1α) stabilization.

CONCLUSIONS

Stroke-induced monocyte Hk2 upregulation is a key mechanism underlying post-stroke vascular inflammation and atheroprogression.

The Transcription Factor SUB1 Is a Master Regulator of the Macrophage TLR Response in Atherosclerosis

Toll-like receptor 2 and 4 (TLR2, TLR4) signaling is implicated in atherosclerotic plaque formation. The two-stage master regulator Virtual Inference of Protein-activity by Enriched Regulon (VIPER) analysis of macrophage TLR2 and TLR4 signature genes integrated with coexpression network genes derived from 371 patient-derived carotid specimens identifies activated RNA polymerase II transcriptional coactivator p15 (SUB1/Sub1, PC4) as a master regulon in the atherogenic TLR response. It is found that TLR2 and TLR4 signaling is proinflammatory and proatherosclerotic in chow-fed apolipoprotein E-deficient (ApoE^-/- ) mice. Through transgenic myeloid-specific Sub1 knockout in ApoE^-/- mice, it is discovered that these proatherosclerotic effects of TLR2 and TLR4 signaling are mediated by Sub1. Sub1 knockout in macrophages enhances anti-inflammatory M2 macrophage polarization and cholesterol efflux. Irradiated low density lipoprotein receptor-deficient (Ldlr^-/- ) mice transplanted with Sub1^-/- murine bone marrow display reduced atherosclerosis. Promoter analysis reveals Sub1-dependent activation of interferon regulatory factor 1 (Irf1) transcription in a casein kinase 2 (Ck2)-dependent manner, and Sub1-knockout macrophages display decreased Irf1 expression. Artificial Irf1 overexpression in Sub1-knockout macrophages enhances proinflammatory M1 skewing and lowers cholesterol clearance. In conclusion, the TLR master regulon Sub1, and its downstream effect on the transcription factor Irf1, promotes a proinflammatory M1 macrophage phenotype and enhances atherosclerotic burden in vivo.

MiR-652-3p inhibition enhances endothelial repair and reduces atherosclerosis by promoting Cyclin D2 expression

BACKGROUND

Atherosclerosis is a hyperlipidemia-induced condition affecting the arterial wall that damages healthy endothelial cell (EC) function, leading to enhanced risk of atherothrombotic events. Certain microRNAs regulate EC dysfunction in response to hyperlipidemia and may be suitable therapeutic targets to combat atherosclerosis.

METHODS

miRNA expression in human ECs was analyzed under various conditions to identify key microRNAs. High-cholesterol diet (HCD)-fed Mir652-/-Apoe-/- (Mir652-/-) mice and matching Mir652+/+Apoe-/- (Mir652+/+) mice were subjected to carotid injury to analyze the effects of miR-652 knockdown on endothelial repair. In silico analysis followed by in vitro and in vivo experiments were applied to identify miR-652's target gene Ccnd2 and investigate the pair's effects on ECs. miR-652-5p and miR-652-3p antagomir therapies were tested in Mir652+/+ mice under normal and HCD diet to assess their effect on endothelial repair.

FINDINGS

miR-652-3p, which is upregulated in human and murine atherosclerotic plaques, suppresses expression of the endothelial repair gene Ccnd2, thereby enhancing atherosclerotic lesion formation. Post-denudation recovery of ECs was promoted in Mir652-/- mice due to enhanced EC proliferation attributable to de-repression of miR-652-3p's (but not miR-652-5p's) regulation of Ccnd2 expression. Under hyperlipidemic conditions at non-predilection sites, miR-652-3p produces anti-proliferative effects in ECs, such that Mir652-/- mice display reduced atherosclerotic progression. In contrast, neither miR-652-3p nor Ccnd2 displayed significant effects on the endothelium at predilection sites or under disturbed flow conditions. Administration of a miR-652-3p antagomir rescued the proliferation of ECs in vivo, thereby limiting atherosclerotic development.

INTERPRETATION

miR-652-3p blockade may be a potential therapeutic strategy against atherosclerosis.

Gut microbiome remodeling induces depressive-like behaviors through a pathway mediated by the host's metabolism

Major depressive disorder (MDD) is the result of complex gene-environment interactions. According to the World Health Organization, MDD is the leading cause of disability worldwide, and it is a major contributor to the overall global burden of disease. However, the definitive environmental mechanisms underlying the pathophysiology of MDD remain elusive. The gut microbiome is an increasingly recognized environmental factor that can shape the brain through the microbiota-gut-brain axis. We show here that the absence of gut microbiota in germ-free (GF) mice resulted in decreased immobility time in the forced swimming test relative to conventionally raised healthy control mice. Moreover, from clinical sampling, the gut microbiotic compositions of MDD patients and healthy controls were significantly different with MDD patients characterized by significant changes in the relative abundance of Firmicutes, Actinobacteria and Bacteroidetes. Fecal microbiota transplantation of GF mice with 'depression microbiota' derived from MDD patients resulted in depression-like behaviors compared with colonization with 'healthy microbiota' derived from healthy control individuals. Mice harboring 'depression microbiota' primarily exhibited disturbances of microbial genes and host metabolites involved in carbohydrate and amino acid metabolism. This study demonstrates that dysbiosis of the gut microbiome may have a causal role in the development of depressive-like behaviors, in a pathway that is mediated through the host's metabolism.

Depression-like behavioral phenotypes by social and social plus visual isolation in the adult female Macaca fascicularis

Major depressive disorder (MDD) is a debilitating psychiatric mood disorder that affects millions of individuals globally. Our understanding of the biological basis of MDD is poor, and current treatments are ineffective in a significant proportion of cases. This current situation may relate to the dominant rodent animal models of depression, which possess translational limitations due to limited homologies with humans. Therefore, a more homologous primate model of depression is needed to advance investigation into the pathophysiological mechanisms underlying depression and to conduct pre-clinical therapeutic trials. Here, we report two convenient methods--social isolation and social plus visual isolation--which can be applied to construct a non-human primate model of depression in the adult female cynomolgus monkey (Macaca fascicularis). Both social and social plus visual isolation were shown to be effective in inducing depression-like behavior by significantly reducing socially dominant aggressive conflict behavior, communicative behavior, sexual behavior, and parental behavior. The addition of visual isolation produced more profound behavioral changes than social isolation alone by further reducing parental behavior and sexual behavior. Thus, the degree of behavioral pathology may be manipulated by the degree of isolation. These methods can be applied to construct a non-human primate model of depression in order to assess physiological, behavioral, and social phenomena in a controlled laboratory setting.

Identification and validation of urinary metabolite biomarkers for major depressive disorder

Major depressive disorder (MDD) is a widespread and debilitating mental disorder. However, there are no biomarkers available to aid in the diagnosis of this disorder. In this study, a nuclear magnetic resonance spectroscopy-based metabonomic approach was employed to profile urine samples from 82 first-episode drug-naïve depressed subjects and 82 healthy controls (the training set) in order to identify urinary metabolite biomarkers for MDD. Then, 44 unselected depressed subjects and 52 healthy controls (the test set) were used to independently validate the diagnostic generalizability of these biomarkers. A panel of five urinary metabolite biomarkers-malonate, formate, N-methylnicotinamide, m-hydroxyphenylacetate, and alanine-was identified. This panel was capable of distinguishing depressed subjects from healthy controls with an area under the receiver operating characteristic curve (AUC) of 0.81 in the training set. Moreover, this panel could classify blinded samples from the test set with an AUC of 0.89. These findings demonstrate that this urinary metabolite biomarker panel can aid in the future development of a urine-based diagnostic test for MDD.