Disruption of USP9X in macrophages promotes foam cell formation and atherosclerosis

E3 ubiquitin ligase RNF128 promotes Lys63-linked polyubiquitination on SRB1 in macrophages and aggravates atherosclerosis

Macrophage-derived foam cell formation is the hallmark of atherosclerotic plaques prominently attributed to excessive lipid uptake and metabolic disorders. As a classic membrane-localized ubiquitin ligase, the role of RNF128 in atherosclerosis remains unknown. We discover that RNF128 is specifically expressed in macrophages of the lipid core based on single-cell RNA sequencing data and persistent hyperlipidemia induces the high expression of RNF128 in macrophages. RNF128 ablation in macrophages ameliorates atherosclerosis in both male and female mice under the background of ApoE and LDLR deficiency. Mechanistically, RNF128 directly binds to scavenger receptor B1 (SRB1), preventing its degradation through the lysosomal system and promoting oxidized low-density lipoprotein (oxLDL)-induced foam cell formation and inflammatory response in macrophages. In addition, RNF128 catalyzes Lys63-linked polyubiquitination on the cytoplasmic C-terminus of the SRB1 at lysine 478, which promotes the endosome SRB1 recycling to the cell membrane with the assistance of Rab11, instead of entering the lysosome for degradation.

Integrating 16S rDNA sequencing analysis and targeted metabolomics to explore the mechanism of Xiexin Tang in treating atherosclerosis mice induced by high-fat diet

Xiexin Tang (XXT) is a classic Chinese medicine formula that can be used to treat Atherosclerosis (AS). This study aimed to investigate the mechanism by which XXT regulated AS lipid levels. Firstly, the mixture components of XXT were analyzed by High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Then, the AS model based on Apolipoprotein E knockout (ApoE-/-) mice was established. Cytokines related to lipid metabolism and bile acid metabolism were detected by Quantitative Real-time PCR (qRT-PCR). 16S rDNA gene sequencing was performed to analyze differential bacterial populations, and the mechanism of XXT regulation of bile acids affecting lipid metabolism was further explored by targeted metabolomics. Further, antibiotic-treated mice were used to investigate the role of gut microbiota in the anti-AS effect of XXT. The results showed that XXT attenuated the lipid levels and reversed the abnormal elevation of cytokines, such as hepatic lipid metabolism and inflammatory reaction in AS mice. XXT also repaired the gut barrier damage and reversed gut microbiota disorders in AS mice. Furthermore, the metabolic levels of bile acids were reshaped by XXT. Whereas, in the absence of gut microbiota, XXT failed to attenuate lipid levels and inhibit the expression of cytokines related to inflammation and bile acid metabolism in AS mice and failed to play a role in ultimately treating AS. In conclusion, XXT could effectively inhibit the inflammatory reaction and lipid accumulation in AS mice, and this effect was closely related to its remodeling of gut microbiota to regulate bile acid metabolism.

FXR activation reduces the formation of macrophage foam cells and atherosclerotic plaque, possibly by down regulating hepatic lipase in macrophages

Macrophages are the most important immune cells affecting the formation of atherosclerotic plaque. Nevertheless, the mechanisms that promote formation of foamy macrophages during atherogenesis remain poorly understood. This study explored the effects of Farnesoid X receptor (FXR) and hepatic lipase (HL, encoded by LIPC) on atherogenesis, particularly in foamy macrophage formation. A luciferase reporter assay indicated that FXR could bind to the LIPC promoter and inhibit LIPC transcription. FXR agonist GW4064 decreased HL expression, foam cell formation, and increased the expression of FXR downstream genes and polarization to M2 in ox-LDL-induced THP-1 and U937 foam cells. In addition, GW4064 exerted anti-atherosclerotic effects in ApoE-/- mice, manifested as decreased serum cholesterol and triglyceride levels, and alleviated atherosclerotic plaque formation. Collectively, FXR exerted anti-atherosclerotic effects, possibly by negatively regulating HL expression in macrophages.

Zdhhc1 deficiency mitigates foam cell formation and atherosclerosis by inhibiting PI3K-Akt-mTOR signaling pathway through facilitating the nuclear translocation of p110α

Monocyte-to-macrophage differentiation and subsequent foam cell formation are key processes that contribute to plaque build-up during the progression of atherosclerotic lesions. Palmitoylation enzymes are known to play pivotal roles in the development and progression of inflammatory diseases. However, their specific impact on atherosclerosis development remains unclear. In this study, we discovered that the knockout of zDHHC1 in THP-1 cells, as well as Zdhhc1 in mice, markedly reduces the uptake of oxidized low-density lipoprotein (ox-LDL) by macrophages, thereby inhibiting foam cell formation. Moreover, the absence of Zdhhc1 in ApoE-/- mice significantly suppresses atherosclerotic plaque formation. Mass spectrometry coupled with bioinformatic analysis revealed an enrichment of the PI3K-Akt-mTOR signaling pathway. Consistent with this, we observed that knockout of zDHHC1 significantly decreases the palmitoylation levels of p110α, a crucial subunit of PI3K. Notably, the deletion of Zdhhc1 facilitates the nuclear translocation of p110α in macrophages, leading to a significant reduction in the downstream phosphorylation of Akt at Ser473 and mTOR at Ser2448. This cascade results in a decreased number of macrophages within plaques and ultimately mitigates the severity of atherosclerosis. These findings unveil a novel role for zDHHC1 in regulating foam cell formation and the progression of atherosclerosis, suggesting it as a promising target for clinical intervention in atherosclerosis therapy.

Deubiquitinase USP9X controls Wnt signaling for CNS vascular formation and barrier maintenance

Deubiquitinating enzymes play crucial roles in various cellular activities, yet their involvement in central nervous system (CNS) vascularization and barrier function remains elusive. Canonical Wnt signaling is essential for proper CNS vascularization and barrier maintenance. Using a loss-of-function screening for Wnt-signaling activity, we identified ubiquitin-specific peptidase 9 X-linked (USP9X) as a key regulator in brain endothelial cells (BECs). Endothelium-specific Usp9x knockout mice exhibit reduced Wnt-signaling activity, compromising CNS vascularization and barrier function during development. Activation of Wnt signaling rescues these defects. Mechanistically, we identified β-catenin as a direct substrate of USP9X, with USP9X catalyzing K48 polyubiquitin chains to stabilize β-catenin. In pathological mouse models of impaired CNS vascular barrier function, including intracerebral hemorrhage and an oxygen-induced retinopathy, loss of Usp9x intensifies barrier disruption, accentuating defects. This finding implicates USP9X as a critical regulator of CNS vascularization and barrier function through Wnt signaling, offering insights into CNS disease implications.

BRISC-Mediated PPM1B-K63 Deubiquitination and Subsequent TGF-β Pathway Activation Promote High-Fat/High-Sucrose Diet-Induced Arterial Stiffness

BACKGROUND

Metabolic syndrome heightens cardiovascular disease risk primarily through increased arterial stiffness. We previously demonstrated the involvement of YAP (Yes-associated protein) in high-fat/high-sucrose diet (HFHSD)-induced arterial stiffness via modulation of PPM1B (protein phosphatase Mg2+/Mn2+-dependent 1B)-lysine 63(K63) deubiquitination. In this study, we aimed to elucidate the role and mechanisms underlying PPM1B deubiquitination in HFHSD-induced arterial stiffness.

METHODS

Enzymes governing PPM1B deubiquitination were identified through small interfering RNA (siRNA) screening and mass spectrometry. Glutathione S-transferase pull-down, coimmunoprecipitation, protein purification, and immunofluorescence were used to explore the mechanism underlying PPM1B deubiquitination. Doppler ultrasound was used to evaluate HFHSD-induced arterial stiffness in mice, and telemetry was used to record pulsatile (systolic and diastolic) blood pressure.

RESULTS

Smooth muscle cell-specific PPM1B overexpression attenuated HFHSD-induced arterial stiffness in mice in a PPM1B-K326-K63-linked polyubiquitination-dependent manner. Mechanistically, ABRO1 (Abraxas brother 1; a core BRCC36 [BRCA1/BRCA2 (breast cancer type 1/2)-containing complex subunit 36] isopeptidase complex component) directly bound YAP and underwent liquid-liquid phase separation with YAP and PPM1B in a YAP-dependent manner, which in turn promoted PPM1B deubiquitination. Furthermore, smooth muscle cell-specific Abro1-knockout mice and Brcc3-knockout mice showed attenuated HFHSD-induced arterial stiffness and activation of transforming growth factor-β-Smad (mothers against decapentaplegic homolog) signaling.

CONCLUSIONS

We elucidated the PPM1B deubiquitination mechanisms and highlighted a potential therapeutic target for metabolic syndrome-related arterial stiffness.

An intimal-lumen model in a microfluidic device: potential platform for atherosclerosis-related studies

Atherosclerosis is a chronic inflammatory vascular disorder driven by factors such as endothelial dysfunction, hypertension, hyperlipidemia, and arterial calcification, and is considered a leading global cause of death. Existing atherosclerosis models have limitations due to the absence of an appropriate hemodynamic microenvironment in vitro and interspecies differences in vivo. Here, we develop a simple but robust microfluidic intimal-lumen model of early atherosclerosis using interconnected dual channels for studying monocyte transmigration and foam cell formation at an arterial shear rate. To the best of our knowledge, this is the first study that creates a physiologically relevant microenvironment under an arterial shear rate to modulate lipid-laden foam cells on a microfluidic platform. As a proof of concept, we use murine endothelial cells to develop a vascular lumen in one channel and collagen-embedded murine smooth muscle cells to mimic the subendothelial intimal layer in another channel. The model successfully triggers endothelial dysfunction upon TNF-α stimulation, initiating monocyte adhesion to the endothelial monolayer under the arterial shear rate. Unlike existing in vitro models, native low-density lipoprotein (LDL) is added in the culture media instead of ox-LDL to stimulate subendothelial lipid accumulation, thereby mimicking more accurate physiology. The subendothelial transmigration of adherent monocytes and subsequent foam cell formation is also achieved under flow conditions in the model. The model also investigates the inhibitory effect of aspirin in monocyte adhesion and transmigration. The model exhibits a significant dose-dependent reduction in monocyte adhesion and transmigration upon aspirin treatment, making it an excellent tool for drug testing.

Salidroside ameliorates macrophages lipid accumulation and atherosclerotic plaque by inhibiting Hif-1α-induced pyroptosis

BACKGROUND

Hipoxia-inducible factor 1 alpha (Hif-1α) is a significant risk factor for atherosclerotic cardiovascular disease. Salidroside (SAL) has demonstrated anti-oxidative and anti-cardiovascular disease effects. Currently, there are no relevant studies investigating the interaction between SAL and Hif-1α in the progression of atherosclerosis.

METHODS

Hif-1α was either knocked down or upregulated in Ana-1 macrophages-derived foam cells, and atherosclerosis ApoE-/- mice were treated with or without SAL. A Protein-protein network involving Hif-1α and pyroptosis-related genes was identified through bioinformatic analysis and validated in human vascular tissues. The Oil Red O and DiI staining were used to detect the intracellular ox-LDL accumulation. The HE and Oil Red O staining were employed to evaluate atherosclerotic plaque in vivo. The levels of relevant molecules were quantified using WB, qRT-PCR, ELISA, and immunohistochemistry. The target proteins of SAL were identified through Molecular docking and Cell Thermal Shift Assay (CESTA).

RESULTS

Both Hif-1α knockdown and SAL treatment markedly reduced lipid accumulation in macrophages-derived foam cells. Hif-1α was closely associated with Caspase1, Gsdmd, NRLP3, and IL-1β, and co-located in CD86+ macrophages-derived foam cells within atherosclerotic plaque. SAL inhibited Hif-1α-induced Caspase-1-dependent pyroptosis and lipid accumulation by directly bonding to Hif-1α. In vivo, SAL treatment decreased atherosclerotic plaque and improved plasma lipid profiles. Furthermore, SAL reduced M1 macrophages infiltration and the levels of Hif-1α, C-Caspase1, Gsdmd-N, NRLP3, IL-18, and IL-1β in atherosclerotic plaque.

CONCLUSION

SAL alleviated the lipid accumulation in macrophages and atherosclerotic plaques by inhibiting pyroptosis pathway via directly binding to Hif-1α, which may be a promising therapeutic strategy for AS treatment.

USP18 Promotes Cholesterol Efflux and Mitigates Atherosclerosis by Deubiquitinating ABCG1

Deubiquitinating enzymes (DUBs) are integral regulators of protein stability. Among these, Ubiquitin-specific protease 18 (USP18) has emerged as a potential therapeutic target for heart failure. However, its precise role in atherosclerosis remains to be comprehensively understood. This study endeavours to examine the impact of USP18 on atherosclerosis and elucidate its corresponding molecular mechanisms. Our studies indicate an elevated expression of USP18 in human coronary atherosclerotic plaques. Notably, the knockdown of USP18 significantly exacerbated lipid accumulation in macrophages. This knockdown effect impaired cholesterol efflux and influenced the downregulation of ATP-binding cassette transporter G1 (ABCG1) expression, achieved by altering the ubiquitination level of ABCG1. Comprehensive mechanistic studies unveiled that USP18 directly affiliates with ABCG1, reducing its ubiquitination and consequently bolstering ABCG1 stability within macrophages. Furthermore, in vivo studies elucidated that the knockdown of USP18 notably elevated atherosclerotic lesions and diminished ABCG1 levels in the plaques of Apoe-/- mice. In summary, our results suggested that USP18 plays a crucial role in managing the progression of atherosclerosis by strengthening the expression of ABCG1 protein through its deubiquitinating effect on ABCG1.

Glia maturation factor-γ regulates amyloid-β42 phagocytosis through scavenger receptor class A type I in murine macrophages

Dysfunctional phagocytic clearance of β-amyloid (Aβ) in microglia and peripheral macrophages/monocytes has been implicated in Alzheimer's disease, but the mechanisms underlying this dysfunction are not yet well understood. In this study, we examined the role of glia maturation factor-γ (GMFG), an actin-disassembly protein, i.e. highly expressed in immune cells, in macrophage Aβ phagocytosis and in regulating type I class A scavenger receptor, a cell-surface receptor that has previously been implicated in Aβ clearance. GMFG knockdown-increased phagocytosis of Aβ42 in bone marrow-derived macrophages and RAW264.7 murine macrophages, while GMFG overexpression reduced Aβ42 uptake in these cells. Blocking with anti-type I class A scavenger receptor antibodies inhibited Aβ42 uptake in GMFG-knockdown cells, establishing a role for type I class A scavenger receptor in Aβ42 phagocytosis. GMFG knockdown-increased type I class A scavenger receptor protein expression under both basal conditions and in response to Aβ42 treatment via both the transcriptional and posttranscriptional levels in RAW264.7 macrophages. GMFG knockdown modulated Aβ42-induced K48-linked and K63-polyubiquitination of type I class A scavenger receptor, the phosphorylation of type I class A scavenger receptor and c-Jun N-Terminal kinase (JNK), suggesting that GMFG plays a role for intracellular signaling in the type I class A scavenger receptor--mediated uptake of Aβ. Further, GMFG-knockdown cells displayed increased levels of the transcriptional factor MafB, and silencing of MafB in these cells reduced their type I class A scavenger receptor expression. Finally, GMFG was found to interact with the nuclear pore complex component RanBP2, and silencing of RanBP2 in GMFG-knockdown cells reduced their type I class A scavenger receptor expression. Collectively, these data support the role of GMFG as a novel regulator of type I class A scavenger receptor in macrophage Aβ phagocytosis and may provide insight into therapeutic approaches to potentially slow or prevent the progression of Alzheimer's disease.

Histone demethylase JMJD1C advances macrophage foam cell formation and atherosclerosis progression by promoting the transcription of PCSK9

Macrophage is considered as a critical driving factor in the progression of atherosclerosis (AS), and epigenetic heterogeneity contributes important mechanisms in this process. Here, we identified that a histone demethylase jumonji domain-containing protein 1 C (JMJD1C) is a promising biomarker for atherosclerotic cerebral infarction through clinical analysis. Then, AOPE-/- mice fed with a high fat diet and RAW264.7 cells induced by oxidized low-density lipoprotein (ox-LDL) were used as AS models to verify the function of JMJD1C in AS development in vivo and in vitro. JMJD1C knockdown significantly reduced plaque area, inflammation and endothelial damage in AS model mice, and also alleviated foam cell formation, inflammatory cytokines production and cell apoptosis in ox-LDL-treated RAW264.7 cells. Mechanistically, JMJD1C promoted the transcription of proprotein convertase subtilisin/kexin type 9 (PCSK9) through mediating H3 Lysine 9 demethylation. The effects of JMJD1C knockdown on ox-LDL-induced macrophages were blocked by PCSK9 overexpression. Altogether, our study proves that JMJD1C advances macrophage foam cell formation, inflammation and apoptosis to accelerate AS progression through H3 demethylation of PCSK9. The findings underscore the important role of JMJD1C-mediated histone modification in macrophage regulation and AS progression, which brings a new insight into the pathobiology of AS.

Leonurine improves atherosclerosis by activating foam cell autophagy and metabolic remodeling via METTL3-mediated AKT1S1 mRNA stability modulation

BACKGROUND

Atherosclerosis (AS) is the most prevalent cardiovascular disease and remains the major contributor to death and mortality globally. Leonurine (LEO) is a unique alkaloid compound with protective effects on the cardiovascular system. However, the exact mechanisms underlying its cardiovascular-protecting action are still not fully elucidated. The methyltransferase 3 (METTL3), the catalytic core of the N6-methyladenosine modification (m6A) methyltransferase complex, has been shown to inhibit autophagy and exacerbate the process of AS via regulation of m6A modification of mRNA.

PURPOSE

We aimed to determine whether the inhibited effect of LEO on AS is related to METTL3-mediated AKT1S1 stability.

METHODS

The apolipoprotein E (ApoE) knockout mice was subjected to a high-fat diet (HFD), and THP-1 derived macrophages was exposed to oxidized low-density lipoprotein (ox-LDL), to establish the animal and cellular models of AS, respectively.

RESULTS

We found that LEO effectively improved AS and reduced the plaque area and inflammation via diminishing macrophage lipid accumulation and remodeling the lipid metabolism profile. LEO activated ox-LDL-induced macrophage autophagy, enhancing lipid metabolism decrease, according to the lipidomic and molecular biology analyses. Additionally, LEO caused a marked increase in autophagy marker levels in mouse models with advanced AS. Furthermore, we found that LEO reactivated autophagy and reversed lipid accumulation by suppressing METTL3 expression. The m6A-seq from ox-LDL-induced macrophages showed that a total of five autophagy-related mRNA transcripts (AKT1S1, AKT1, RB1CC1, CFLAR, and MTMR4) were altered, and AKT1S1 was significantly upregulated by LEO. Mechanistically, LEO-mediated regulation of METTL3 decreased AKT1S1 expression by attenuating its mRNA stability. Silencing AKT1S1 inhibited LEO-METTL3 axis-mediated autophagy and enhanced lipid accumulation in ox-LDL-induced macrophages.

CONCLUSION

The study first revealed that LEO exerts anti-atherosclerotic effect by activating METTL3-mediated macrophage autophagy in vivo and in vitro. The mechanism of LEO was further found to be the enhancement of METTL3-mediated AKT1S1 stability to activate autophagy thereby reducing lipid accumulation. This study provides a new perspective of natural medicines on the treatment of AS via an epigenetic manner.

Interaction between adipocytes and macrophages participates in chick subcutaneous adipose tissue angiogenesis under cold stress conditions

Previous studies have shown that subcutaneous adipose tissue is an important energy supply organ for chicks before and after birth, except yolk. So far, the significance of large deposits of subcutaneous adipose tissue in chicks is unclear. Therefore, this study takes the information interaction between adipocytes and macrophages as the starting point to explore whether adipocytes and macrophages could participate in adipose tissue fibrosis, angiogenesis, adaptive thermogenesis and other related functions in a specific metabolic environment. Under cold stress, the expression levels of genes related to lipidolysis, lipid transport and fatty acid oxidation in adipose tissue of chicks were significantly increased, but the expression levels of genes related to mitochondrial uncoupling were not significantly changed. Through Masson staining of adipose tissue of chicks under cold stress, it was found that the level of vascularization in adipose tissue of chicks was significantly increased. We found that the interaction between adipocyte and macrophage could participate in the angiogenesis related process of adipocytes in chicks through the HIF1A-VEGFA pathway. The analysis of lipid metabolism in subcutaneous adipose tissue of chicks from the perspective of cell heterogeneity will expand the understanding of lipid metabolism in chicks and provide a theoretical basis for chick rearing.

Reduced circulating CD63+ extracellular vesicle levels associate with atherosclerosis in hypercholesterolaemic mice and humans

AIMS

The association and co-isolation of low-density lipoproteins (LDL) and extracellular vesicles (EVs) have been shown in blood plasma. Here we explore this relationship to better understand the role of EVs in atherogenesis.

METHODS AND RESULTS

Wild type (WT), PCSK9-/-, and LDLR-/- C57BL/6 mice were used in this study. Eleven week-old male mice were fed high-fat diet (HFD) for 12 weeks or kept on normal diet until old age (22-months). Cardiac function was assessed by ultrasound, cholesterol was quantified with a colorimetric kit and circulating EVs were measured using flow cytometry. Plaques were analysed post-mortem using Oil-Red-O staining of the aortic arch. EVs were measured from platelet free blood plasma samples of normal and hypercholesterolaemic clinical patients. Based on annexin V and CD63 staining, we found a significant increase in EV levels in LDLR-/- and PCSK9-/- mice after HFD, but CD81 showed no significant change in either group. There was no significant change in plaque formation after HFD. PCSK9-/- mice show a favourable cardiac function after HFD. Blood cholesterol levels progressively increased during HFD, with LDLR-/- mice showing high levels while PCSK9-/- were significantly lowered compared to WT animals. In mice at old age, similar cholesterol levels were observed as in young mice. In old age, LDLR-/- mice showed significantly increased plaques. At old age, ejection fraction was decreased in all groups of mice, as were CD63+ EVs. Similarly to mice, in patients with hypercholesterolaemia, CD63+ EVs were significantly depleted.

CONCLUSIONS

This research demonstrates an inverse relationship between circulating EVs and cholesterol, making EVs a potential marker for cardiovascular disease (CVD). HFD causes reduced cardiac function, but atherosclerotic development is slowly progressing in hypercholesterolaemic models and only observed with old animals. These results also bring further evidence for the benefit of using of PCSK9 inhibitors as therapeutic agents in CVD.

Novel Metal-Free Nanozyme for Targeted Imaging and Inhibition of Atherosclerosis via Macrophage Autophagy Activation to Prevent Vulnerable Plaque Formation and Rupture

Atherosclerosis is a primary cause of cardiovascular and cerebrovascular diseases, with the unpredictable rupture of vulnerable atherosclerotic plaques enriched with lipid-laden macrophages being able to lead to heart attacks and strokes. Activating macrophage autophagy presents itself as a promising strategy for preventing vulnerable plaque formation and reducing the risk of rupture. In this study, we have developed a novel metal-free nanozyme (HCN@DS) that integrates the functions of multimodal imaging-guided therapy for atherosclerosis. HCN@DS has demonstrated high macrophage-targeting abilities due to its affinity toward scavenger receptor A (SR-A), along with excellent photoacoustic and photothermal imaging capabilities for guiding the precise treatment. It combines mild photothermal effects with moderate reactive oxygen species (ROS) generation to treat atherosclerosis. This controlled approach activates autophagy in atherosclerotic macrophages, inhibiting foam cell formation by reducing the uptake of oxidized low-density lipoproteins (oxLDL) and promoting efferocytosis and cholesterol efflux in macrophages. Additionally, it prevents plaque rupture by inhibiting apoptosis and inflammation within the plaque. Therefore, this metal-free nanozyme holds great potential for reducing the risk of atherosclerosis due to its high biosafety, excellent targeting ability, dual-modality imaging capability, and appropriate modulation of autophagy.

PGC1α enhances macrophage efferocytosis in ox-LDL-stimulated RAW264.7 cells by regulating the NLRP3/PPARα axis

BACKGROUND

Defective clearance of apoptotic and foam cells achieved by arterial macrophage efferocytosis propels the progression of inflammatory atherosclerosis, but related molecular mechanisms in this process remain unclear. Herein, this study is engineered to probe into the mechanism of peroxisome-proliferator-activated receptor-γ coactivator-1α (PGC1α) on atherosclerosis.

METHODS

The PGC1α/NLR family pyrin domain containing 3 (NLRP3)/peroxisome proliferator activated receptor alpha (PPARα) axis in oxidized low-density lipoprotein (ox-LDL)-induced RAW264.7 cells was verified using Western blot. Inflammatory response, NLRP3 activation, efferocytotic efficiency and lipid uptake of the ox-LDL-stimulated cells overexpressing PGC1α or/and silencing PPARα were detected by enzyme-linked immunosorbent assay, immunofluorescence, tracing of apoptotic Jurkat cells and Oil red O staining.

RESULTS

PGC1α and PPARα levels were decreased, but NLRP3 level was increased in ox-LDL-stimulated RAW264.7 cells (P<0.001). PGC1α overexpression repressed the levels of IL-1β, IL-6 and TNF-α, NLRP3 expression or activation and foam cell formation (P<0.05), but enhanced efferocytosis as well as expressions of AXL, MERTK and TYRO3 in ox-LDL-stimulated cells (P<0.001). PGC1α overexpression increased PPARα expression. However, PPARα silencing reversed the effects of PGC1α overexpression on protecting macrophages against ox-LDL-induced inflammation, efferocytotic impairment and foam cell formation (P<0.05).

CONCLUSION

Overexpression PGC1α decreased NLRP3 activation to promoted the expression of PPARα, which alleviated the impairment of macrophage efferocytosis and inhibited the development of atherosclerosis development.

High expression levels of haem oxygenase-1 promote ferroptosis in macrophage-derived foam cells and exacerbate plaque instability

Plaque rupture with consequent thrombosis is the leading cause of acute cardiovascular events, during which macrophage death is a hallmark. Ferroptosis is a pivotal intermediate link between early and advanced atherosclerosis. Existing evidence indicates the involvement of macrophage ferroptosis in plaque vulnerability; however, the exact mechanism remains elusive. The aim of this study was to explore key ferroptosis-related genes (FRGs) involved in plaque progression and the underlying molecular mechanisms involved. The expression landscape of FRGs was obtained from atherosclerosis-related GEO datasets. Molecular mechanism studies of ferroptosis were performed using bone marrow-derived macrophages (BMDMs) and macrophage-derived foam cells (MDFCs). Bioinformatics analysis and immunohistochemistry revealed that macrophage haem oxygenase-1 (HMOX1) is the key FRG involved in plaque destabilization. Hypoxic conditions induced a significant increase in Hmox1 expression in MDFCs but not in macrophages. In addition, the beneficial or deleterious effects of Hmox1 were dependent on the degree of Hmox1 induction. Hmox1 overexpression drove inflammatory responses and ferroptotic oxidative stress in MDFCs and aggravated the plaque burden in atherosclerotic model mice. Further mechanistic investigations demonstrated that hypoxia-mediated degradation of egl-9 family hypoxia-inducible factor 3 (Egln3) stabilized Hif1a, which subsequently promoted Hmox1 transcription. Our findings suggest that high Hmox1 expression under hypoxia is deleterious to MDFC viability and plaque stability, providing a reference for the management of acute cardiovascular events.

Knocking out USP7 attenuates cardiac fibrosis and endothelial-to-mesenchymal transition by destabilizing SMAD3 in mice with heart failure with preserved ejection fraction

Background: Heart failure with preserved ejection fraction (HFpEF) is a predominant type of heart failure. Exploring new pathogenesis and identifying potential novel therapeutic targets for HFpEF is of paramount importance. Methods: HFpEF mouse model was established by the "Multiple-hit" strategy, in that 18- to 22-month-old female C57B6/J mice fed with a high-fat diet were further challenged with chronic infusion of Angiotensin II. RNA sequencing analysis showed that USP7 was significantly increased in the heart of HFpEF mice. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis, in conjunction with co-immunoprecipitation (Co-IP) techniques, identified expression of SMAD3, the key molecule of endothelial-to-mesenchymal transition (EndMT), was also significantly elevated. USP7 endothelium-specific knockout mice was generated to investigate the involvement of USP7 in HFpEF. The biological significance of the interaction between USP7 and SMAD3 was further explored. Results: USP7 promotes EndMT and cardiac fibrosis by binding to SMAD3 directly via its UBL (Ubiquitin-like) domain and cysteine at position 223 of USP7, leading SMAD3 deubiquitination to maintain the stability of SMAD3 by removing the K63 ubiquitin chain and preventing the degradation of SMAD3 by proteasomal process. USP7 also promotes SMAD3 phosphorylation and nuclear translocation, thereby aggravating EndMT and cardiac fibrosis. Endothelium-specific USP7 knockout led to improvement of HFpEF phenotypes and reduction of cardiac fibrosis. Overexpression of SMAD3 in endothelium-specific knockout HFpEF mice reversed the protective effects of USP7 knockout in this HFpEF mouse model. Conclusion: Our results indicated that USP7 is one of the key pathogenic molecules of HFpEF, and knocking out USP7 could attenuate HFpEF injury by promoting the degradation of SMAD3. USP7 and SMAD3 inhibition might be potential therapeutic options for HFpEF.

Circ_0006476 modulates macrophage apoptosis through the miR-3074-5p/DLL4 axis: implications for Notch signalling pathway regulation in cardiovascular disease

As the population ages, the prevalence of atherosclerosis (AS), a significant cause of cardiovascular disease (CVD), continues to increase. Apoptosis is an independent risk factor for atherosclerosis. Macrophages are the primary immune cell group in AS lesions, and their apoptosis plays a crucial role in the occurrence and development of AS. There is a common mechanism of action for circular RNAs (circRNAs) that involves the sponging of microRNAs (miRNAs) by binding to the miRNA response element (MRE), thereby increasing the transcription of their target messenger RNAs (mRNAs). Most diseases are profoundly reliant on circRNAs. However, the underlying mechanism of circRNAs in apoptosis is yet to be elucidated. All differentially expressed genes (DEGs) and their expression levels were analysed by whole-transcriptome sequencing of samples from the control and nicotine groups of THP-1 macrophages. GO and KEGG analyses revealed that nicotine affects macrophage physiological processes and related pathways. GSEA focused on gene sets to better understand the potential pathways and biological functions of all mRNAs. A competitive endogenous RNA (ceRNA) regulatory network was constructed and validated through molecular biology experiments. The Notch signalling pathway was activated in nicotine-treated macrophages, and the expression of DLL4 in this pathway was increased. Circ_0006476 is involved in apoptosis via miR-3074-5p/DLL4, regulating pathogenic processes related to the Notch signalling pathway. The better we understand the pathways involved in macrophage apoptosis, the more likely we are to find other novel therapeutic targets that can help treat, prevent, and reduce the mortality associated with AS.

An integrated bioinformatics analysis reveals IRF8 as a critical biomarker for immune infiltration in atherosclerosis advance

Atherosclerosis, a lipid-driven chronic inflammatory disorder, is a significant global health concern associated with high rates of morbidity and mortality, imposing a substantial societal burden. The purpose of this study is to investigate the possible molecular mechanisms of atherosclerosis and identify potential therapeutic targets. We conducted an integrated bioinformatics analysis using data from peripheral blood mononuclear cell and TISSUE databases obtained from the Gene Expression Omnibus, to identify key genes associated with the progression of atherosclerosis. Here, IRF8 was found to be a key gene in atherosclerosis patients. Silencing IRF8 with small interfering RNA reduced inflammation in endothelial cells. This suggests IRF8 is a crucial biomarker for immune infiltration in atherosclerosis advance.

LncRNA DANCR promotes macrophage lipid accumulation through modulation of membrane cholesterol transporters

The progression of atherosclerosis (AS), the pathological foundation of coronary artery disease (CAD), is featured by massive lipid deposition in the vessel wall. LncRNAs are implicated in lipid disorder and AS, whereas the specific role of lncRNA DANCR in atherogenesis remains unknown. Here, we demonstrated that DANCR promotes macrophage lipid accumulation by regulating the expression of membrane cholesterol transport proteins. qPCR showed that compared to control groups, CAD patients and atherosclerotic mice had higher DANCR levels. Treating human THP-1 macrophages and mouse RAW264.7 macrophages with ox-LDL significantly upregulated the expression levels of DANCR. Oil Red O staining showed that the silence of DANCR robustly reduced, while overexpression of DANCR significantly increased the numbers and size of lipid droplets in ox-LDL-treated THP-1 macrophages. In contrast, the opposite phenomena were observed in DANCR overexpressing cells. The expression of ABCA1, ABCG1, SR-BI, and NBD-cholesterol efflux was increased obviously by DANCR inhibition and decreased by DANCR overexpression, respectively. Furthermore, transfection with DANCR siRNA induced a robust decrease in the levels of CD36, SR-A, and Dil-ox-LDL uptake, while DANCR overexpression amplified the expression of CD36, SR-A and the uptake of Dil-ox-LDL in lipid-laden macrophages. Lastly, we found that the effects of DANCR on macrophage lipid accumulation and the expression of membrane cholesterol transport proteins were not likely related to miR-33a. The present study unraveled the adverse role of DANCR in foam cell formation and its relationship with cholesterol transport proteins. However, the competing endogenous RNA network underlying these phenomena warrants further exploration.

Vitamin D and Atherosclerosis: Unraveling the Impact on Macrophage Function

Vitamin D plays a crucial role in preventing atherosclerosis and in the regulation of macrophage function. This review aims to provide a comprehensive summary of the clinical evidence regarding the impact of vitamin D on atherosclerotic cardiovascular disease, atherosclerotic cerebrovascular disease, peripheral arterial disease, and associated risk factors. Additionally, it explores the mechanistic studies investigating the influence of vitamin D on macrophage function in atherosclerosis. Numerous findings indicate that vitamin D inhibits monocyte or macrophage recruitment, macrophage cholesterol uptake, and esterification. Moreover, it induces autophagy of lipid droplets in macrophages, promotes cholesterol efflux from macrophages, and regulates macrophage polarization. This review particularly focuses on analyzing the molecular mechanisms and signaling pathways through which vitamin D modulates macrophage function in atherosclerosis. It claims that vitamin D has a direct inhibitory effect on the formation, adhesion, and migration of lipid-loaded monocytes, thus exerting anti-atherosclerotic effects. Therefore, this review emphasizes the crucial role of vitamin D in regulating macrophage function and preventing the development of atherosclerosis.

Macrophage polarisation and inflammatory mechanisms in atherosclerosis: Implications for prevention and treatment

Atherosclerosis is a chronic inflammatory disease characterised by plaque accumulation in the arteries. Macrophages are immune cells that are crucial in the development of atherosclerosis. Macrophages can adopt different phenotypes, with the M1 phenotype promoting inflammation while the M2 phenotype counteracting it. This review focuses on the factors that drive the polarisation of M1 macrophages towards a pro-inflammatory phenotype during AS. Additionally, we explored metabolic reprogramming mechanisms and cytokines secretion by M1 macrophages. Hyperlipidaemia is widely recognised as a major risk factor for atherosclerosis. Modified lipoproteins released in the presence of hyperlipidaemia can trigger the release of cytokines and recruit circulating monocytes, which adhere to the damaged endothelium and differentiate into macrophages. Macrophages engulf lipids, leading to the formation of foam cells. As atherosclerosis progresses, foam cells become the necrotic core within the atherosclerotic plaques, destabilising them and triggering ischaemic disease. Furthermore, we discuss recent research focusing on targeting macrophages or inflammatory pathways for preventive or therapeutic purposes. These include statins, PCSK9 inhibitors, and promising nanotargeted drugs. These new developments hold the potential for the prevention and treatment of atherosclerosis and its related complications.

Gualou-Xiebai herb pair and its active ingredients act against atherosclerosis by suppressing VSMC-derived foam cell formation via regulating P2RY12-mediated lipophagy

BACKGROUND

Atherosclerosis (AS) is a chronic disease characterized by lipid accumulation in the aortic wall and the formation of foam cells overloaded with large lipids inclusions. Currently, Western medicine is primarily used to improve lipid metabolism disorders and reduce inflammatory reactions to delay AS progression, but these medicines come with serious side effects and drug resistance. Gualou-Xiebai (GLXB) is a renowned herb pair that has been proven effective against AS. However, the potential molecular mechanism through which GLXB exerts the anti-atherosclerotic effects of increasing lipophagy in vascular smooth muscle cells (VSMCs) remains unknown.

PURPOSE

This study aims to explore the role of lipophagy and the therapeutic mechanism of GLXB in AS.

METHODS

UPLC-Q-TOF-MS for the determination of the main components of GLXB-containing serum. An AS mouse model was established by feeding a high-fat diet (HFD) to ApoE-/- mice for 12 weeks. Ultrasonography monitoring was used to confirm the successful establishment of the AS model. Plaque areas and lipid deposition were evaluated using HE staining and aorta imagingafter GLXB treatment. Immunofluorescence staining and Western blotting were utilized to observe the P2RY12 and lipophagy levels in AS mice. VSMCs were stimulated with oxidized low-density lipoprotein (ox-LDL) to induce foam cell formation. The degree of lipophagy and the related molecular mechanisms were assessed after treating the VSMCs with GLXB-containing serum or si-P2RY12 transfection. The active components of GLXB-containing serum that act on P2RY12 were screened and verified by molecular docking and dual-luciferase reporter assays.

RESULTS

Seventeen components of GLXB were identified in rat serum by UPLC-Q-TOF-MS. GLXB significantly reduced lipid deposition in HFD-fed ApoE-/- mice and ox-LDL-induced VSMCs. GLXB strikingly increased lipophagy levels by downregulating P2RY12, p62, and plin2, upregulating LC3Ⅱ protein expression, and increasing the number of autophagosomes. Notably, the lipophagy inhibitor CQ and the P2RY12 receptor agonist ADPβ abolished the GLXB-induced increase in lipophagy. Last, we confirmed that albiflorin, apigenin, luteolin, kaempferol, 7,8-dihydroxyflavone, and hesperetin from GLXB significantly inhibited P2RY12.

CONCLUSION

GLXB activates lipophagy and inhibits lipid accumulation-associated VSMC-derived foam cell formation through suppressing P2RY12 activation, resulting in anti-atherosclerotic effects. The GLXB components albiflorin, apigenin, luteolin, kaempferol, 7,8-dihydroxyflavone, and hesperetin are the potential active effectors against P2RY12.

Chronotherapy involving rosiglitazone regulates the phenotypic switch of vascular smooth muscle cells by shifting the phase of TNF-α rhythm through triglyceride accumulation in macrophages

Objectives

Vascular diseases are often caused by the interaction between macrophages and vascular smooth muscle cells (VSMCs). This study aims to elucidate whether chronotherapy with rosiglitazone (RSG) can regulate the secretion rhythm of macrophages, thereby controlling the phenotypic switch of VSMCs and clarifying the potential molecular mechanisms, providing a chronotherapeutic approach for the treatment of vascular diseases.

Methods

RAW264.7 cells and A7r5 cells were synchronized via a 50 % FBS treatment. M1-type macrophages were induced through Lipopolysaccharide (LPS) exposure. Additionally, siRNA and plasmids targeting PPARγ were transfected into macrophages. The assessment encompassed cell viability, migration, inflammatory factor levels, lipid metabolites, clock gene expression, and relative protein expression.

Results

We revealed that, in alignment with core clock genes Bmal1 and CLOCK, RSG administration at ZT2 advanced the phase of TNF-α release rhythm, while ZT12 administration shifted it backward. Incubation with TNF-α at ZT2 significantly promoted the phenotype switch of VSMCs. This effect diminished when incubated at ZT12, implicating the involvement of the clock-MAPK pathway in VSMCs. Furthermore, RSG administration at ZT2 advanced the phases of PPARγ and Bmal1 genes, whereas ZT12 administration shifted them backward. Additionally, PPARγ overexpression significantly induced triglyceride (TG) accumulation in macrophages. Exogenous TG upregulated Bmal1 and CLOCK gene expression in macrophages and significantly increased TNF-α release.

Conclusion

Chronotherapy involving RSG induces TG accumulation within macrophages, resulting in alterations in circadian gene rhythms. These changes, in turn, modulate the phase of rhythmic TNF-α release and play a regulatory role in VSMCs phenotype switch. Our study establishes a theoretical foundation for chronotherapy of PPARγ agonists.

Cellular functions, molecular signalings and therapeutic applications: Translational potential of deubiquitylating enzyme USP9X as a drug target in cancer treatment

Protein ubiquitination, one of the most significant post-translational modifications, plays an important role in controlling the proteins activity in diverse cellular processes. The reversible process of protein ubiquitination, known as deubiquitination, has emerged as a critical mechanism for maintaining cellular homeostasis. The deubiquitinases (DUBs), which participate in deubiquitination process are increasingly recognized as potential candidates for drug discovery. Among these DUBs, ubiquitin-specific protease 9× (USP9X), a highly conserved member of the USP family, exhibits versatile functions in various cellular processes, including the regulation of cell cycle, protein endocytosis, apoptosis, cell polarity, immunological microenvironment, and stem cell characteristics. The dysregulation and abnormal activities of USP9X are influenced by intricate cellular signaling pathway crosstalk and upstream non-coding RNAs. The complex expression patterns and controversial clinical significance of USP9X in cancers suggest its potential as a prognostic biomarker. Furthermore, USP9X inhibitors has shown promising antitumor activity and holds the potential to overcome therapeutic resistance in preclinical models. However, a comprehensive summary of the role and molecular functions of USP9X in cancer progression is currently lacking. In this review, we provide a comprehensive delineation of USP9X participation in numerous critical cellular processes, complicated signaling pathways within the tumor microenvironment, and its potential translational applications to combat therapeutic resistance. By systematically summarizing the updated molecular mechanisms of USP9X in cancer biology, this review aims to contribute to the advancement of cancer therapeutics and provide essential insights for specialists and clinicians in the development of improved cancer treatment strategies.

Ubiquitous regulation of cerebrovascular diseases by ubiquitin-modifying enzymes

Cerebrovascular diseases (CVDs) are a major threat to global health. Elucidation of the molecular mechanisms underlying the pathology of CVDs is critical for the development of efficacious preventative and therapeutic approaches. Accumulating studies have highlighted the significance of ubiquitin-modifying enzymes (UMEs) in the regulation of CVDs. UMEs are a group of enzymes that orchestrate ubiquitination, a post-translational modification tightly involved in CVDs. Functionally, UMEs regulate multiple pathological processes in ischemic and hemorrhagic stroke, moyamoya disease, and atherosclerosis. Considering the important roles of UMEs in CVDs, they may become novel druggable targets for these diseases. Besides, techniques applying UMEs, such as proteolysis-targeting chimera and deubiquitinase-targeting chimera, may also revolutionize the therapy of CVDs in the future.

Uptake of ox-LDL by binding to LRP6 mediates oxidative stress-induced BMSCs senescence promoting obesity-related bone loss

Obesity has long been thought to be a main cause of hyperlipidemia. As a systemic disease, the impact of obesity on organs, tissues and cells is almost entirely negative. However, the relationship between obesity and bone loss is highly controversial. On the one hand, obesity has long been thought to have a positive effect on bone due to increased mechanical loading on the skeleton, conducive to increasing bone mass to accommodate the extra weight. On the other hand, obesity-related metabolic oxidative modification of low-density lipoprotein (LDL) in vivo causes a gradual increase of oxidized LDL (ox-LDL) in the bone marrow microenvironment. We have reported that low-density lipoprotein receptor-related protein 6 (LRP6) acts as a receptor of ox-LDL and mediates the bone marrow stromal cells (BMSCs) uptake of ox-LDL. We detected elevated serum ox-LDL in obese mice. We found that ox-LDL uptake by LRP6 led to an increase of intracellular reactive oxygen species (ROS) in BMSCs, and N-acetyl-L-cysteine (NAC) alleviated the cellular senescence and impairment of osteogenesis induced by ox-LDL. Moreover, LRP6 is a co-receptor of Wnt signaling. We found that LRP6 preferentially binds to ox-LDL rather than dickkopf-related protein 1 (DKK1), both inhibiting Wnt signaling and promoting BMSCs senescence. Mesoderm development LRP chaperone (MESD) overexpression inhibits ox-LDL binding to LRP6, attenuating oxidative stress and BMSCs senescence, eventually rescuing bone phenotype.

Biological significance of METTL5 in atherosclerosis: comprehensive analysis of single-cell and bulk RNA sequencing data

BACKGROUND

N6-methyladenosine (m6A) methylation is involved in the pathogenesis of atherosclerosis (AS). Limited studies have examined the role of the m6A methyltransferase METTL5 in AS pathogenesis.

METHODS

This study subjected the AS dataset to differential analysis and weighted gene co-expression network analysis to identify m6A methylation-associated differentially expressed genes (DEGs). Next, the m6A methylation-related DEGs were subjected to consensus clustering to categorize AS samples into distinct m6A subtypes. Single-cell RNA sequencing (scRNA-seq) analysis was performed to investigate the proportions of each cell type in AS and adjacent healthy tissues and the expression levels of key m6A regulators. The mRNA expression levels of METTL5 in AS and healthy tissues were determined using quantitative real-time polymerase chain reaction (qRT-PCR) analysis.

RESULTS

AS samples were classified into two subtypes based on a five-m6A regulator-based model. scRNA-seq analysis revealed that the proportions of T cells, monocytes, and macrophages in AS tissues were significantly higher than those in healthy tissues. Additionally, the levels of m6A methylation were significantly different between AS and healthy tissues. METTL5 expression was upregulated in macrophages, smooth muscle cells (SMCs), and endothelial cells (ECs). qRT-PCR analysis demonstrated that the METTL5 mRNA level in AS tissues was downregulated when compared with that in healthy tissues.

CONCLUSIONS

METTL5 is a potential diagnostic marker for AS subtypes. Macrophages, SMCs, and ECs, which exhibit METTL5 upregulation, may modulate AS progression by regulating m6A methylation levels.

SLAMF7 Promotes Foam Cell Formation of Macrophage by Suppressing NR4A1 Expression During Carotid Atherosclerosis

Macrophage-derived lipid-laden foam cells from the subendothelium play a crucial role in the initiation and progression of atherosclerosis. However, the molecule mechanism that regulates the formation of foam cells is not completely understood. Here, we found that SLAMF7 was upregulated in mice bone marrow-derived macrophages and RAW264.7 cells stimulated with oxidized low-density lipoprotein (ox-LDL). SLAMF7 promoted ox-LDL-mediated macrophage lipid accumulation and M1-type polarization. SLAMF7 deficiency reduced serum lipid levels and improved the lesions area of carotid plaque and aortic arch in high-fat diet-fed ApoE-/- mice. In response to ox-LDL, SLAMF7 downregulated NR4A1 and upregulated RUNX3 through transcriptome sequencing analysis. Overexpression NR4A1 reversed SLAMF7-induced lipid uptake and M1 polarization via inhibiting RUNX3 expression. Furthermore, RUNX3 enhanced foam cell formation and M1-type polarization. Taken together, the study suggested that SLAMF7 play contributing roles in the pro-atherogenic effects by regulating NR4A1-RUNX3.

The effects of glycosylation modifications on monocyte recruitment and foam cell formation in atherosclerosis

The monocyte recruitment and foam cell formation have been intensively investigated in atherosclerosis. Nevertheless, as the study progressed, it was obvious that crucial molecules participated in the monocyte recruitment and the membrane proteins in macrophages exhibited substantial glycosylation modifications. These modifications can exert a significant influence on protein functions and may even impact the overall progression of diseases. This article provides a review of the effects of glycosylation modifications on monocyte recruitment and foam cell formation. By elaborating on these effects, we aim to understand the underlying mechanisms of atherogenesis further and to provide new insights into the future treatment of atherosclerosis.

Photodynamic Therapy for Atherosclerosis

Atherosclerosis, which currently contributes to 31% of deaths globally, is of critical cardiovascular concern. Current diagnostic tools and biomarkers are limited, emphasizing the need for early detection. Lifestyle modifications and medications form the basis of treatment, and emerging therapies such as photodynamic therapy are being developed. Photodynamic therapy involves a photosensitizer selectively targeting components of atherosclerotic plaques. When activated by specific light wavelengths, it induces localized oxidative stress aiming to stabilize plaques and reduce inflammation. The key advantage lies in its selective targeting, sparing healthy tissues. While preclinical studies are encouraging, ongoing research and clinical trials are crucial for optimizing protocols and ensuring long-term safety and efficacy. The potential combination with other therapies makes photodynamic therapy a versatile and promising avenue for addressing atherosclerosis and associated cardiovascular disease. The investigations underscore the possibility of utilizing photodynamic therapy as a valuable treatment choice for atherosclerosis. As advancements in research continue, photodynamic therapy might become more seamlessly incorporated into clinical approaches for managing atherosclerosis, providing a blend of efficacy and limited invasiveness.

Emerging applications of single-cell profiling in precision medicine of atherosclerosis

Atherosclerosis is a chronic, progressive, inflammatory disease that occurs in the arterial wall. Despite recent advancements in treatment aimed at improving efficacy and prolonging survival, atherosclerosis remains largely incurable. In this review, we discuss emerging single-cell sequencing techniques and their novel insights into atherosclerosis. We provide examples of single-cell profiling studies that reveal phenotypic characteristics of atherosclerosis plaques, blood, liver, and the intestinal tract. Additionally, we highlight the potential clinical applications of single-cell analysis and propose that combining this approach with other techniques can facilitate early diagnosis and treatment, leading to more accurate medical interventions.

Roles of ubiquitin-specific proteases in inflammatory diseases

Ubiquitin-specific proteases (USPs), as one of the deubiquitinating enzymes (DUBs) families, regulate the fate of proteins and signaling pathway transduction by removing ubiquitin chains from the target proteins. USPs are essential for the modulation of a variety of physiological processes, such as DNA repair, cell metabolism and differentiation, epigenetic modulations as well as protein stability. Recently, extensive research has demonstrated that USPs exert a significant impact on innate and adaptive immune reactions, metabolic syndromes, inflammatory disorders, and infection via post-translational modification processes. This review summarizes the important roles of the USPs in the onset and progression of inflammatory diseases, including periodontitis, pneumonia, atherosclerosis, inflammatory bowel disease, sepsis, hepatitis, diabetes, and obesity. Moreover, we highlight a comprehensive overview of the pathogenesis of USPs in these inflammatory diseases as well as post-translational modifications in the inflammatory responses and pave the way for future prospect of targeted therapies in these inflammatory diseases.

JOSD2 mediates isoprenaline-induced heart failure by deubiquitinating CaMKIIδ in cardiomyocytes

Prolonged stimulation of β-adrenergic receptor (β-AR) can lead to sympathetic overactivity that causes pathologic cardiac hypertrophy and fibrosis, ultimately resulting in heart failure. Recent studies suggest that abnormal protein ubiquitylation may contribute to the pathogenesis of cardiac hypertrophy and remodeling. In this study, we demonstrated that deficiency of a deubiquitinase, Josephin domain-containing protein 2 (JOSD2), ameliorated isoprenaline (ISO)- and myocardial infarction (MI)-induced cardiac hypertrophy, fibrosis, and dysfunction both in vitro and in vivo. Conversely, JOSD2 overexpression aggravated ISO-induced cardiac pathology. Through comprehensive mass spectrometry analysis, we identified that JOSD2 interacts with Calcium-calmodulin-dependent protein kinase II (CaMKIIδ). JOSD2 directly hydrolyzes the K63-linked polyubiquitin chains on CaMKIIδ, thereby increasing the phosphorylation of CaMKIIδ and resulting in calcium mishandling, hypertrophy, and fibrosis in cardiomyocytes. In vivo experiments showed that the cardiac remodeling induced by JOSD2 overexpression could be reversed by the CaMKIIδ inhibitor KN-93. In conclusion, our study highlights the role of JOSD2 in mediating ISO-induced cardiac remodeling through the regulation of CaMKIIδ ubiquitination, and suggests its potential as a therapeutic target for combating the disease. Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary. All have been checked.

Roles of USP9X in cellular functions and tumorigenesis (Review)

Ubiquitin-specific peptidase 9X (USP9X) is involved in certain human diseases, including malignancies, atherosclerosis and certain diseases of the nervous system. USP9X promotes the deubiquitination and stabilization of diverse substrates, thereby exerting a versatile range of effects on pathological and physiological processes. USP9X serves vital roles in the processes of cell survival, invasion and migration in various types of cancer. The present review aims to highlight the current knowledge of USP9X in terms of its structure and the possible mediatory mechanisms involved in certain types of cancer, providing a thorough introduction to its biological functions in carcinogenesis and further outlining its oncogenic or suppressive properties in a diverse range of cancer types. Finally, several perspectives regarding USP9X-targeted pharmacological therapeutics in cancer development are discussed.

USP9X deubiquitinates and stabilizes CDC123 to promote breast carcinogenesis through regulating cell cycle

Cell division cycle 123 (CDC123) has been implicated in a variety of human diseases. However, it remains unclear whether CDC123 plays a role in tumorigenesis and how its abundance is regulated. In this study, we found that CDC123 was highly expressed in breast cancer cells, and its high expression was positively correlated with a poor prognosis. Knowndown of CDC123 impaired the proliferation of breast cancer cells. Mechanistically, we identified a deubiquitinase, ubiquitin-specific peptidase 9, X-linked (USP9X), that could physically interact with and deubiquitinate K48-linked ubiquitinated CDC123 at the K308 site. Therefore, the expression of CDC123 was positively correlated with USP9X in breast cancer cells. In addition, we found that deletion of either USP9X or CDC123 led to altered expression of cell cycle-related genes and resulted in the accumulation of cells population in the G0/G1 phase, thereby suppressing cell proliferation. Treatment with the deubiquitinase inhibitor of USP9X, WP1130 (Degrasyn, a small molecule compound that USP9X deubiquitinase inhibitor), also led to the accumulation of breast cancer cells in the G0/G1 phase, but this effect could be rescued by overexpression of CDC123. Furthermore, our study revealed that the USP9X/CDC123 axis promotes the occurrence and development of breast cancer through regulating the cell cycle, and suggests that it may be a potential target for breast cancer intervention. In conclusion, our study demonstrates that USP9X is a key regulator of CDC123, providing a novel pathway for the maintenance of CDC123 abundance in cells, and supports USP9X/CDC123 as a potential target for breast cancer intervention through regulating the cell cycle.

Targeting gut microbiota and immune crosstalk: potential mechanisms of natural products in the treatment of atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory reaction that primarily affects large and medium-sized arteries. It is a major cause of cardiovascular disease and peripheral arterial occlusive disease. The pathogenesis of AS involves specific structural and functional alterations in various populations of vascular cells at different stages of the disease. The immune response is involved throughout the entire developmental stage of AS, and targeting immune cells presents a promising avenue for its treatment. Over the past 2 decades, studies have shown that gut microbiota (GM) and its metabolites, such as trimethylamine-N-oxide, have a significant impact on the progression of AS. Interestingly, it has also been reported that there are complex mechanisms of action between GM and their metabolites, immune responses, and natural products that can have an impact on AS. GM and its metabolites regulate the functional expression of immune cells and have potential impacts on AS. Natural products have a wide range of health properties, and researchers are increasingly focusing on their role in AS. Now, there is compelling evidence that natural products provide an alternative approach to improving immune function in the AS microenvironment by modulating the GM. Natural product metabolites such as resveratrol, berberine, curcumin, and quercetin may improve the intestinal microenvironment by modulating the relative abundance of GM, which in turn influences the accumulation of GM metabolites. Natural products can delay the progression of AS by regulating the metabolism of GM, inhibiting the migration of monocytes and macrophages, promoting the polarization of the M2 phenotype of macrophages, down-regulating the level of inflammatory factors, regulating the balance of Treg/Th17, and inhibiting the formation of foam cells. Based on the above, we describe recent advances in the use of natural products that target GM and immune cells crosstalk to treat AS, which may bring some insights to guide the treatment of AS.

Novel Insights into the Molecular Mechanisms of Atherosclerosis

Atherosclerosis is one of the most fatal diseases in the world. The associated thickening of the arterial wall and its background and consequences make it a very composite disease entity with many mechanisms that lead to its creation. It is an active process, and scientists from various branches are engaged in research, including molecular biologists, cardiologists, and immunologists. This review summarizes the available information on the pathophysiological implications of atherosclerosis, focusing on endothelium dysfunction, inflammatory factors, aging, and uric acid, vitamin D, and miRNA expression as recent evidence of interactions of the molecular and cellular elements. Analyzing new discoveries for the underlying causes of this condition assists the general research to improve understanding of the mechanism of pathophysiology and thus prevention of cardiovascular diseases.

lnc-MRGPRF-6:1 Promotes ox-LDL-Induced Macrophage Ferroptosis via Suppressing GPX4

Background

Ferroptosis, a newly discovered mode of cell death, emerges as a new target for atherosclerosis (AS). Long noncoding RNAs (lncRNAs) are involved in the regulation of ferroptosis. In our previous study, lnc-MRGPRF-6:1 was highly expressed in patients with coronary atherosclerotic disease (CAD) and closely associated with macrophage-mediated inflammation in AS. In the present study, we aim to investigate the role of lnc-MRGPRF-6:1 in oxidized-low-density lipoprotein (ox-LDL)-induced macrophage ferroptosis in AS.

Methods

Firstly, ox-LDL-treated macrophages were used to simulate macrophage injury in AS. Then, ferroptosis-related biomarkers and mitochondrial morphology were detected and observed in ox-LDL-treated macrophages. Subsequently, we constructed lnc-MRGPRF-6:1 knockdown and overexpression of THP-1-derived macrophages and investigated the role of lnc-MRGPRF-6:1 in ox-LDL-induced ferroptosis. Then human monocytes were isolated successfully and were used to explore the role of lnc-MRGPRF-6:1 in macrophage ferroptosis. Likely, we constructed lnc-MRGPRF-6:1 knockdown and overexpression of human monocyte-derived macrophages and detected the expression levels of ferroptosis-related biomarkers. Then, transcriptome sequencing, literature searching, and following quantitative real-time polymerase chain reaction and western blot were implemented to explore specific signaling pathway in the process. It was demonstrated that lnc-MRGPRF-6:1 may regulate ox-LDL-induced macrophage ferroptosis through glutathione peroxidase 4 (GPX4). Eventually, the correlation between lnc-MRGPRF-6:1 and GPX4 was measured in monocyte-derived macrophages of CAD patients and controls.

Results

The ox-LDL-induced injury in macrophages was involved in ferroptosis. The knockdown of lnc-MRGPRF-6:1 could alleviate ox-LDL-induced ferroptosis in macrophages. Meanwhile, the overexpression of lnc-MRGPRF-6:1 could intensify ox-LDL-induced ferroptosis. Furthermore, the knockdown of lnc-MRGPRF-6:1 could alleviate the decrease of GPX4 induced by RAS-selective lethal compounds 3 (RSL-3). These indicated that lnc-MRGPRF-6:1 may suppress GPX4 to induce macrophage ferroptosis. Eventually, lnc-MRGPRF-6:1 was highly expressed in the monocyte-derived macrophages of CAD patients and was negatively correlated with the expression of GPX4.

Conclusion

lnc-MRGPRF-6:1 can promote ox-LDL-induced macrophage ferroptosis through inhibiting GPX4.

Transaldolase inhibits CD36 expression by modulating glutathione-p38 signaling, exerting protective effects against macrophage foam cell formation

In atherosclerosis, macrophage-derived foam cell formation is considered to be a hallmark of the pathological process; this occurs via the uptake of modified lipoproteins. In the present study, we aim to determine the role of transaldolase in foam cell formation and atherogenesis and reveal the mechanisms underlying its role. Bone marrow-derived macrophages (BMDMs) isolated from mice successfully form foam cells after treatment with oxidized low-density lipoprotein (80 μg/mL). Elevated transaldolase levels in the foam cell model are assessed by quantitative polymerase chain reaction and western blot analysis. Transaldolase overexpression and knockdown in BMDMs are achieved via plasmid transfection and small interfering RNA technology, respectively. We find that transaldolase overexpression effectively attenuates, whereas transaldolase knockdown accelerates, macrophage-derived foam cell formation through the inhibition or activation of cholesterol uptake mediated by the scavenger receptor cluster of differentiation 36 (CD36) in a p38 mitogen-activated protein kinase (MAPK) signaling-dependent manner. Transaldolase-mediated glutathione (GSH) homeostasis is identified as the upstream regulator of p38 MAPK-mediated CD36-dependent cholesterol uptake in BMDMs. Transaldolase upregulates GSH production, thereby suppressing p38 activity and reducing the CD36 level, ultimately preventing foam cell formation and atherosclerosis. Thus, our findings indicate that the transaldolase-GSH-p38-CD36 axis may represent a promising therapeutic target for atherosclerosis.

Tussilagone attenuates atherosclerosis through inhibiting MAPKs-mediated inflammation in macrophages

Atherosclerosis is a common chronic inflammatory disease. Recent studies have highlighted the key role of macrophages and inflammation in process of atherosclerotic lesion formation. A natural product, tussilagone (TUS), has previously exhibited anti-inflammatory activities in other diseases. In this study, we explored the potential effects and mechanisms of TUS on the inflammatory atherosclerosis. Atherosclerosis was induced in ApoE^-/- mice by feeding them with a high-fat diet (HFD) for 8 weeks, followed by administration of TUS (10, 20 mg ·kg^-1·d^-1, i.g.) for 8 weeks. We demonstrated that TUS alleviated inflammatory response and reduced atherosclerotic plaque areas in HFD-fed ApoE^-/- mice. Pro-inflammatory factor and adhesion factors were inhibited by TUS treatment. In vitro, TUS suppressed foam cell formation and oxLDL-induced inflammatory response in MPMs. RNA-sequencing analysis indicated that MAPK pathway was related to the anti-inflammation and anti-atherosclerosis effects of TUS. We further confirmed that TUS inhibited MAPKs phosphorylation in plaque lesion of aortas and cultured macrophages. MAPK inhibition blocked oxLDL-induced inflammatory response and prevented the innately pharmacological effects of TUS. Our findings present a mechanistic explanation for the pharmacological effect of TUS against atherosclerosis and indicate TUS as a potentially therapeutic candidate for atherosclerosis.

Research progress on the active ingredients of traditional Chinese medicine in the intervention of atherosclerosis: A promising natural immunotherapeutic adjuvant

Atherosclerosis (AS) is a chronic inflammatory disease caused by disorders of lipid metabolism. Abnormal deposition of low-density lipoproteins in the arterial wall stimulates the activation of immune cells, including the adhesion and infiltration of monocytes, the proliferation and differentiation of macrophages and lymphocytes, and the activation of their functions. The complex interplay between immune cells coordinates the balance between pro- and anti-inflammation and plays a key role in the progression of AS. Therefore, targeting immune cell activity may lead to the development of more selective drugs with fewer side effects to treat AS without compromising host defense mechanisms. At present, an increasing number of studies have found that the active ingredients of traditional Chinese medicine (TCM) can regulate the function of immune cells in multiple ways to against AS, showing great potential for the treatment of AS and promising clinical applications. In this paper, we review the mechanisms of immune cell action in AS lesions and the potential targets and/or pathways for immune cell regulation by the active ingredients of TCM to promote the understanding of the immune system interactions of AS and provide a relevant basis for the use of active ingredients of TCM as natural adjuvants for AS immunotherapy.

Effects of Hydroxytyrosol in Endothelial Functioning: A Comprehensive Review

Pharmacologists have been emphasizing and applying plant and herbal-based treatments in vascular diseases for decades now. Olives, for example, are a traditional symbol of the Mediterranean diet. Hydroxytyrosol is an olive-derived compound known for its antioxidant and cardioprotective effects. Acknowledging the merit of antioxidants in maintaining endothelial function warrants the application of hydroxytyrosol in endothelial dysfunction salvage and recovery. Endothelial dysfunction (ED) is an impairment of endothelial cells that adversely affects vascular homeostasis. Disturbance in endothelial functioning is a known precursor for atherosclerosis and, subsequently, coronary and peripheral artery disease. However, the effects of hydroxytyrosol on endothelial functioning were not extensively studied, limiting its value either as a nutraceutical supplement or in clinical trials. The action of hydroxytyrosol in endothelial functioning at a cellular and molecular level is gathered and summarized in this review. The favorable effects of hydroxytyrosol in the improvement of endothelial functioning from in vitro and in vivo studies were scrutinized. We conclude that hydroxytyrosol is capable to counteract oxidative stress, inflammation, vascular aging, and arterial stiffness; thus, it is beneficial to preserve endothelial function both in vitro and in vivo. Although not specifically for endothelial dysfunction, hydroxytyrosol safety and efficacy had been demonstrated via in vivo and clinical trials for cardiovascular-related studies.

Ubiquitin-Specific Proteases (USPs) and Metabolic Disorders

Ubiquitination and deubiquitination are reversible processes that modify the characteristics of target proteins, including stability, intracellular localization, and enzymatic activity. Ubiquitin-specific proteases (USPs) constitute the largest deubiquitinating enzyme family. To date, accumulating evidence indicates that several USPs positively and negatively affect metabolic diseases. USP22 in pancreatic β-cells, USP2 in adipose tissue macrophages, USP9X, 20, and 33 in myocytes, USP4, 7, 10, and 18 in hepatocytes, and USP2 in hypothalamus improve hyperglycemia, whereas USP19 in adipocytes, USP21 in myocytes, and USP2, 14, and 20 in hepatocytes promote hyperglycemia. In contrast, USP1, 5, 9X, 14, 15, 22, 36, and 48 modulate the progression of diabetic nephropathy, neuropathy, and/or retinopathy. USP4, 10, and 18 in hepatocytes ameliorates non-alcoholic fatty liver disease (NAFLD), while hepatic USP2, 11, 14, 19, and 20 exacerbate it. The roles of USP7 and 22 in hepatic disorders are controversial. USP9X, 14, 17, and 20 in vascular cells are postulated to be determinants of atherosclerosis. Moreover, mutations in the Usp8 and Usp48 loci in pituitary tumors cause Cushing syndrome. This review summarizes the current knowledge about the modulatory roles of USPs in energy metabolic disorders.

Single-cell transcriptome sequencing of macrophages in common cardiovascular diseases

Macrophages are strategically located throughout the body at key sites in the immune system. A key feature in atherosclerosis is the uptake and accumulation of lipoproteins by arterial macrophages, leading to the formation of foam cells. After myocardial infarction, macrophages derived from monocytes infiltrate the infarcted heart. Macrophages are also closely related to adverse remodeling after heart failure. An in-depth understanding of the functions and characteristics of macrophages is required to study heart health and pathophysiological processes; however, the heterogeneity and plasticity explained by the classic M1/M2 macrophage paradigm are too limited. Single-cell sequencing is a high-throughput sequencing technique that enables the sequencing of the genome or transcriptome of a single cell. It effectively complements the heterogeneity of gene expression in a single cell that is ignored by conventional sequencing and can give valuable insights into the development of complex diseases. In the present review, we summarize the available research on the application of single-cell transcriptome sequencing to study the changes in macrophages during common cardiovascular diseases, such as atherosclerosis, myocardial infarction, and heart failure. This article also discusses the contribution of this knowledge to understanding the pathogenesis, development, diagnosis, and treatment of heart diseases.

USP9X-mediated NRP1 deubiquitination promotes liver fibrosis by activating hepatic stellate cells

Liver fibrosis is a complex fibrotic process that develops early in the course of cirrhosis and is caused by chronic liver damage. The activation of hepatic stellate cells is primarily responsible for the fibrosis process. Studies show that NRP1 influences HSC motility and migration. However, whether NRP1 regulates HSC activation remains unknown. C57BL/6 male mice (6-8 weeks old) were intraperitoneally injected with 10% CCl₄ in olive oil (5 μl/g body weight) every three days for four weeks to create an animal model of liver fibrosis. Control mice received olive oil (5 μl/g body weight). Different assays such as immunohistochemistry, immunostaining, Western blotting, qRT-PCR, immunoprecipitation, immunoprecipitation, and GST pull-down assays, and in vivo and in vitro ubiquitination assays were conducted. We found that NRP1 expression was significantly elevated both in mouse and human fibrotic livers, mainly in activated HSCs at the fibrotic foci. NRP1 promoted HSC activation via the cytokine TGF-β1, VEGFA, and PDGF-BB. Moreover, USP9X was found to be a critical deubiquitinating enzyme for the stability and high activity of NRP1 and NRP1 deubiquitination mediated by USP9X enhanced HSC activation and liver fibrosis. NRP1 deubiquitination mediated by USP9X enhances HSC activation, implying that targeting NRP1 or USP9X potentiates novel options in the treatment of liver fibrosis.

Assessing the Progression of Early Atherosclerosis Mice Using a Fluorescence Nanosensor for the Simultaneous Detection and Imaging of pH and Phosphorylation

The inflammatory microenvironment involves changes in pH and protein phosphorylation state and is closely related to the occurrence and development of atherosclerosis (AS). Herein, we constructed a dual-detection fluorescence nanosensor PCN-NP-HPZ based on post modification of MOFs, which realized the simultaneous detection and imaging of pH and phosphorylation through the pH-sensitive group piperazine and the Zr^IV node of the MOFs. The sensors were used to monitor changes in blood pH and phosphate levels at different time stages during atherosclerotic plaque formation. Two-photon fluorescence imaging was also performed in the vascular endothelium. Blood tests combined with two-photon fluorescence images indicated that in the early stage of AS, blood and tissue pH levels were lower than that of the normal mice, while phosphate and tissue phosphorylation levels were higher than that of the normal mice. The present study provides a new analysis method for the assessment of early atherosclerotic disease.

Disruption of COMMD1 accelerates diabetic atherosclerosis by promoting glycolysis

AIMS

Diabetes will lead to serious complications, of which atherosclerosis is the most dangerous. This study aimed to explore the mechanisms of diabetic atherosclerosis.

METHODS

ApoE^-/- mice were fed with an high-fat diet diet and injected with streptozotocin to establish an in vivo diabetic atherosclerotic model. RAW 264.7 cells were treated with oxidized low-density lipoprotein particles (ox-LDL) and high glucose to produce an in vitro diabetic atherosclerotic model.

RESULTS

In this study, we showed that diabetes promoted the progression of atherosclerosis in ApoE^-/- mice and that high glucose potentiates macrophage proinflammatory activation and foam cell formation. Mechanistically, Copper metabolism MURR1 domain-containing 1(COMMD1) deficiency increased proinflammatory activation and foam cell formation, characterized by increased glycolysis, and then accelerated the process of atherosclerosis. Furthermore, 2-Deoxy-D-glucose (2-DG) reversed this effect.

CONCLUSION

Taken together, we provided evidence that the lack of COMMD1 accelerates diabetic atherosclerosis via mediating the metabolic reprogramming of macrophages. Our study provides evidence of a protective role for COMMD1 and establishes COMMD1 as a potential therapeutic strategy in patients with diabetic atherosclerosis.