The roles of p62/SQSTM1 on regulation of matrix metalloproteinase-9 gene expression in response to oxLDL in atherosclerosis

CircSKA3 is Associated With the Risk of Extracranial Artery Stenosis and Plaque Instability Among Ischemic Stroke Patients

Circular RNA circSKA3 (spindle and kinetochore-related complex subunit 3) has been identified as a prognostic factor in ischemic stroke. The objective of this study was to investigate the association of circSKA3 with the risk of extracranial artery stenosis (ECAS) and plaque instability in patients with ischemic stroke. We constructed a competing endogenous RNA (ceRNA) network regulated by circSKA3 based on differentially expressed circRNAs and mRNAs between five patients and five controls. Gene Ontology (GO) analysis was performed on the 65 mRNAs within the network, revealing their primary involvement in inflammatory biological processes. A total of 284 ischemic stroke patients who underwent various imaging examinations were included for further analyses. Each 1 standard deviation increase in the log-transformed blood circSKA3 level was associated with a 56.3% increased risk of ECAS (P = 0.005) and a 142.1% increased risk of plaque instability (P = 0.005). Patients in the top tertile of circSKA3 had a 2.418-fold (P < 0.05) risk of ECAS compared to the reference group (P for trend = 0.02). CircSKA3 demonstrated a significant but limited ability to discriminate the presence of ECAS (AUC = 0.594, P = 0.015) and unstable carotid plaques (AUC = 0.647, P = 0.034). CircSKA3 improved the reclassification power for ECAS (NRI: 9.86%, P = 0.012; IDI: 2.97%, P = 0.007) and plaque instability (NRI: 36.73%, P = 0.008; IDI: 7.05%, P = 0.04) beyond conventional risk factors. CircSKA3 played an important role in the pathogenesis of ischemic stroke by influencing inflammatory biological processes. Increased circSKA3 was positively associated with the risk of ECAS and plaque instability among ischemic stroke patients.

Identification of Oxidative Stress-Related Biomarkers in Acute Myocardial Infarction

Purpose

Acute Myocardial Infarction (AMI) is globally prevalent, with oxidative stress as a key contributor to its pathogenesis. This study aimed to explore oxidative stress-related genes as potential AMI biomarkers, elucidating their role in disease progression.

Patients and Methods

Gene expression data from AMI samples in the Gene Expression Omnibus (GEO) database and oxidative stress-related genes (OSRGs) from the GeneCards database were extracted. Weighted Gene Co-expression Network Analysis (WGCNA) identified key module genes associated with AMI. Intersecting OSRGs, key module genes, and differentially expressed genes (DEGs) between AMI and normal samples led to the extraction of differentially expressed ORSGs (DE-ORSGs) related to AMI. Feature genes were mined using the Least Absolute Shrinkage and Selection Operator (LASSO) regression and Support Vector Machine (SVM) algorithm, followed by potential diagnostic value assessment using receiver operating characteristic (ROC) curves. Gene Set Enrichment Analysis (GSEA) was executed on the identified key genes. Immune infiltration levels were explored using the CIBERSORT algorithm, and a Transcription Factor (TF) -mRNA regulatory network of key genes was created. The key genes were validated using qRT-PCR.

Results

We authenticated three key genes (MMP9, TGFBR3, and S100A12) from 6 DE-ORSGs identified in AMI. GSEA revealed that these key genes were enriched in immune-related signaling pathways. Immune infiltration analysis identified three differential immune cell types (resting NK cells, Monocytes, and M0 Macrophages) between AMI and normal groups. Correlation analysis revealed positive associations of MMP9 with M0 Macrophages and S100A12 with Monocytes and M0 Macrophages, whereas TGFBR3 was negatively related to Monocytes. A TF-mRNA regulatory network was generated based on these key genes. qRT-PCR validation confirmed the differential expression of S100A12 and TGFBR3 between AMI and control samples.

Conclusion

TGFBR3, and S100A12 were identified as potential oxidative stress-related biomarkers in AMI, providing new insights for AMI diagnosis and treatment.

Baicalin alleviates Mycoplasma gallisepticum-induced oxidative stress and inflammation via modulating NLRP3 inflammasome-autophagy pathway

Baicalin is a well-known flavonoid compound, possess therapeutic potential against inflammatory diseases. Previous studies reported that Mycoplasma gallisepticum (MG) induced inflammatory response and immune dysregulation inside the host body. However, the underlying molecular mechanisms of baicalin against MG-infected chicken-like macrophages (HD11 cells) are still illusive. Oxidant status and total reactive oxygen species (ROS) were detected by ELISA assays and flow cytometry respectively. Mitochondrial membrane potential (ΔΨ_M) was evaluated by immunofluorescence microscopy. Transmission electron microscopy was used for ultrastructural analysis. The hallmarks of inflammation and autophagy were determined by western blotting. Oxidative stress and reactive oxygen species (ROS) were significantly enhanced in the MG-infected HD11 cells. MG infection caused disruption in the mitochondrial membrane potential (ΔΨ_M) compared to the control conditions. Meanwhile, baicalin treatment reduced MG-induced reactive oxygen species (ROS), oxidative stress and alleviated the disruption in ΔΨ_M. The activities of inflammatory markers were significantly enhanced in the MG-infected HD11 cells. Increased protein expressions of TLR-2-NF-κB pathway, NLRP3-inflammasome and autophagy-related proteins were detected in the MG-infected HD11 cells. Besides, baicalin treatment significantly reduced the protein expressions of TLR-2-NF-κB pathway and NLRP3 inflammasome. While, the autophagy-related proteins were significantly enhanced with baicalin treatment in a dose-dependent manner in the MG-infected HD11 cells. The results showed that baicalin prevented HD11 cells from MG-induced oxidative stress and inflammation via the opposite modulation of TLR-2-NF-κB-mediated NLRP3-inflammasome pathway and autophagy, and baicalin could be a promising candidate for the prevention of inflammatory effects caused by MG-infection in macrophages.

MiRNA-130a promotes inflammation to accelerate atherosclerosis via the regulation of proliferator-activated receptor γ (PPARγ) expression

OBJECTIVE

In this study, we aimed to evaluate the possible function of miR-130a in atherosclerosis (AS), protection against AS, and its molecular biological mechanism.

METHODS

Apoe-/- mice were fed a high-fat diet as the AS mice model. Human umbilical vein endothelial cells (HUVECs) were used as in vitro model. Serum samples or cells were used to measure the expression of inflammation. Serum samples or cells were used to determine MiRNA expression profiles using the edgeR tool from Bioconductor. Western Blot analysis was used to assess protein expressions of proliferator-activated receptor γ (PPARγ) and nuclear factor (NF)-κB.

RESULTS

MiRNA-130a expression was up-regulated in atherosclerotic mice. In addition, over-expression of miRNA-130a promoted inflammation factors [tumor necrosis factor (TNF)-α and interleukin (IL)-1β, IL-6, and IL-8] in the in vitro model of AS. However, down-regulation of miRNA-130a reduced inflammation (suppressed TNF-α, IL-1β, IL-6 and IL-8) in the in vitro model. Furthermore, over-expression of miRNA-130a could also suppress the protein expression of PPARγ and induce NF-κB protein expression in the in vitro model. However, suppression of miRNA-130a induced the protein expression of PPARγ and suppressed NF-κB protein expression in the in vitro model of AS. Activation of PPARγ reduced the pro-inflammatory effects of miRNA-130a on the AS-induced in vitro model.

CONCLUSION

These results strongly support that miRNA-130a suppression can protect against atherosclerosis through inhibiting inflammation by regulating the PPARγ/ NF-κB expression.

GDF-15 Deficiency Reduces Autophagic Activity in Human Macrophages In Vitro and Decreases p62-Accumulation in Atherosclerotic Lesions in Mice

(1) Background: Growth differentiation factor-15 (GDF-15) is associated with cardiovascular diseases and autophagy in human macrophages (MΦ). Thus, we are interested in investigating autophagic mechanisms with special respect to the role of GDF-15. (2) Methods: Recombinant (r)GDF-15 and siRNA GDF-15 were used to investigate the effects of GDF-15 on autophagic and lysosomal activity, as well as autophagosome formation by transmission electron microscopy (TEM) in MΦ. To ascertain the effects of GDF-15-/- on the progression of atherosclerotic lesions, we used GDF-15-/-/ApoE-/- and ApoE-/- mice under a cholesterol-enriched diet (CED). Body weight, body mass index (BMI), blood lipid levels and lumen stenosis in the brachiocephalic trunk (BT) were analyzed. Identification of different cell types and localization of autophagy-relevant proteins in atherosclerotic plaques were performed by immunofluorescence. (3) Results: siGDF-15 reduced and, conversely, rGDF-15 increased the autophagic activity in MΦ, whereas lysosomal activity was unaffected. Autophagic degradation after starvation and rGDF-15 treatment was observed by TEM. GDF-15-/-/ApoE-/- mice, after CED, showed reduced lumen stenosis in the BT, while body weight, BMI and triglycerides were increased compared with ApoE-/- mice. GDF-15-/- decreased p62-accumulation in atherosclerotic lesions, especially in endothelial cells (ECs). (4) Conclusion: GDF-15 seems to be an important factor in the regulation of autophagy, especially in ECs of atherosclerotic lesions, indicating its crucial pathophysiological function during atherosclerosis development.

Effects and Mechanism of Noninvasive Positive-Pressure Ventilation in a Rat Model of Heart Failure Due to Myocardial Infarction

BACKGROUND Impaired heart function induced by myocardial infarction is a leading cause of chronic heart failure (HF). This study aimed to investigate the effects and mechanism of noninvasive positive-pressure ventilation (NIPPV) in a rat model of HF due to myocardial infarction. MATERIAL AND METHODS To explore the therapeutic effect and mechanism of NIPPV on acute myocardial infarction-induced HF, we established a rat model of HF by ligating the anterior descending branch of the left coronary artery and confirmed by ultrasonic cardiography and brain natriuretic peptide 45 detection. RESULTS The levels of heat-shock protein (HSP)-70 increased and matrix metalloproteinase (MMP)-2, MMP-9, and tumor necrosis factor (TNF)-alpha decreased in the group that received NIPPV treatment compared with the control group. In addition, the histopathologic results showed less severe inflammatory infiltration and a smaller area of myocardial fibrosis in the NIPPV treatment group. CONCLUSIONS In a rat model of HF due to myocardial infarction, NIPPV resulted in increased levels of HSP70 and reduced expression of MMP2, MMP9, and TNF-alpha and reduced myocardial neutrophil infiltration and fibrosis. Taken together, we showed that NIPPV is an effective treatment for HF induced by myocardial infarction by inhibiting the release of inflammatory factors and preventing microvascular embolism.

MicroRNA-761 modulates foam cell formation and inflammation through autophagy in the progression of atherosclerosis

Macrophage-derived foam cells formation is the initial stage of atherosclerosis, and lipid-laden macrophage accumulation is also considered as the symbol of unstable plaque. Autophagy is a subcellular process responsible for the degradation of damaged organelles and aggregated proteins in cells (Grootaert in Oxid Med Cell Longev: 7687083, 2018). Macrophage autophagy plays an important role in atherosclerosis under various stress conditions, and microRNAs are involved in this complicated process. The present study was programmed to explore the effects of microRNA-761 on macrophage-derived foam cell formation, focusing on the role of autophagy in this pathological process. The differentiated human THP-1 macrophages were used in the study. THP-1-derived macrophages were treated with miR-761 mimics or inhibitors and cultured with oxidized low-density lipoprotein to mimic the lipid-rich environment in blood vessel. The expression of miR-761 and mRNA levels of IL-1β and IL-18 were analyzed by quantitative real-time PCR. The effect of miR-761 on autophagy was evaluated by the protein levels of Beclin1, p62/SQSTM1, microtubule-associated protein light chain 3, mammalian target of rapamycin (mTOR), and unc-51-like autophagy activating kinase 1 (ULK1), determined by immunoblot and autophagic flux detected by fluorescent staining. The secretion of IL-1β and IL-18 was tested by enzyme-linked immunosorbent reaction kit. Lipid accumulation in foam cells was detected by oil red "O" staining. We demonstrated that miR-761 was able to repress foam cell formation and reduce the production of atherogenic inflammatory cytokines IL-1β and IL-18 in an autophagy-dependent manner in atherosclerosis, possibly via mTOR-ULK1 signaling pathway. In summary, we described an athero-protective function of miR-761 in macrophages incubated with excess ox-LDL and identified an important novel modulator of mTOR signaling and autophagy in macrophage-derived foam cells. This finding may provide a potential target for the prevention and early treatment in high-risk group of atherosclerosis.

TPM2 as a potential predictive biomarker for atherosclerosis

Cardiac-cerebral vascular disease (CCVD), is primarily induced by atherosclerosis, and is a leading cause of mortality. Numerous studies have investigated and attempted to clarify the molecular mechanisms of atherosclerosis; however, its pathogenesis has yet to be completely elucidated. Two expression profiling datasets, GSE43292 and GSE57691, were obtained from the Gene Expression Omnibus (GEO) database. The present study then identified the differentially expressed genes (DEGs), and functional annotation of the DEGs was performed. Finally, an atherosclerosis animal model and neural network prediction model was constructed to verify the relationship between hub gene and atherosclerosis. The results identified a total of 234 DEGs between the normal and atherosclerosis samples. The DEGs were mainly enriched in actin filament, actin binding, smooth muscle cells, and cytokine-cytokine receptor interactions. A total of 13 genes were identified as hub genes. Following verification of animal model, the common DEG, Tropomyosin 2 (TPM2), was found, which were displayed at lower levels in the atherosclerosis models and samples. In summary, DEGs identified in the present study may assist clinicians in understanding the pathogenesis governing the occurrence and development of atherosclerosis, and TPM2 exhibits potential as a promising diagnostic and therapeutic biomarker for atherosclerosis.

p62/mTOR/LXRα pathway inhibits cholesterol efflux mediated by ABCA1 and ABCG1 during autophagy blockage

OBJECTIVE

Atherosclerosis is a disease characterized by abnormal lipid metabolism, and the formation of foam cells is considered an early event of atherosclerosis. Intracellular cholesterol efflux mediated by ABCA1 and ABCG1 helps to reduce lipid accumulation in foam cells. Related studies have shown that autophagy and mTOR are involved in cholesterol efflux, but the role of p62, an autophagy substrate protein, has not been evaluated.

METHODS

THP-1 derived macrophages were incubated with ox-LDL to establish a foam cell model and treated with different autophagy inducers. The effects of p62 on cholesterol efflux were investigated using overexpression vectors, gene silencing and western blotting.

RESULTS

This study showed a blockage of autophagy and decreased expression of ABCA1 and ABCG1 under the stress of excess ox-LDL in a concentration-dependent manner in THP-1 cells. Furthermore, the activation of autophagy led to increased expression of ABCA1 and ABCG1, as well as their upstream transcription factor LXRα, thereby promoting cholesterol efflux from foam cells. We also demonstrated that accumulated p62 played an important role during autophagy blockage, which was achieved by activating mTOR and then inhibited the expression of LXRα and its downstream target proteins ABCA1 and ABCG1.

CONCLUSION

In conclusion, our experiments demonstrated that a p62/mTOR/LXRα signaling pathway was involved in cholesterol efflux mediated by ABCA1 and ABCG1 when autophagy blockage occurred. Our study offers a rationale for the development of autophagy and p62 as a new target for the treatment of atherosclerosis.

Ginkgo Biloba Leaf Extract Attenuates Atherosclerosis in Streptozotocin-Induced Diabetic ApoE-/- Mice by Inhibiting Endoplasmic Reticulum Stress via Restoration of Autophagy through the mTOR Signaling Pathway

Background

There is a crosstalk between endoplasmic reticulum stress (ERS) and autophagy, and autophagy could attenuate endoplasmic reticulum stress-mediated apoptosis. Ginkgo biloba leaf extract (GBE) exerts vascular protection functions. The purpose of the present study is to investigate the role of autophagy in diabetic atherosclerosis (AS) and the effect of GBE on autophagy and ERS.

Methods

Network pharmacology was utilized to predict the targets and pathways of the active chemical compounds of Gingko biloba leaf to attenuate AS. ApoE^−/− mice were rendered diabetic by intraperitoneal ingestion with streptozotocin combined with a high-fat diet. The diabetic mice were divided into five groups: model group, atorvastatin group, rapamycin group, and low- and high-dose GBE groups. Serum and tissue markers of autophagy or ERS markers, including the protein expression, were examined.

Results

The mammalian target of rapamycin (mTOR) and NF-κB signaling pathways were targeted by the active chemical compounds of GBE to attenuate AS predicted by network pharmacology. GBE reduced the plaque area/lumen area and the plaque lipid deposition area/intimal area and inhibited the expressions of CD68, MMP2, and MMP9. Rapamycin and GBE inhibited the expression of mTOR and SQSTM1/p62 which increased in the aorta of diabetic mice. In addition, GBE reduced the expression of ERS markers in diabetic mice. GBE reduced the serum lipid metabolism levels, blood glucose, and inflammatory cytokines.

Conclusion

Impaired autophagy and overactive endoplasmic reticulum stress contributed to diabetic atherosclerosis. mTOR inhibitor rapamycin and GBE attenuated diabetic atherosclerosis by inhibiting ERS via restoration of autophagy through inhibition of mTOR.

Growth differentiation factor-15 regulates oxLDL-induced lipid homeostasis and autophagy in human macrophages

BACKGROUND AND AIMS

Growth differentiation factor-15 (GDF-15)/macrophage inhibitory cytokine-1 (MIC-1/GDF15) is associated with cardiovascular disease, inflammation and development of atherosclerosis and is highly expressed in macrophages (MΦ) of atherosclerotic lesions. Thus, we were interested in investigating the influence of GDF-15 in lipid homeostasis and autophagy in human MΦ during foam cell formation.

METHODS AND RESULTS

Oxidized-low density lipoprotein (50 μg/ml oxLDL), recombinant (r)GDF-15, transiently silenced GDF-15 (siGDF-15 MΦ), as well as with negative siRNA transfected (nsiGDF-15 MΦ) PMA-differentiated human THP-1 MΦ, were used to investigate the effects of GDF-15 on autophagic processes and lipid accumulation. Oil Red O staining revealed that rGDF-15 alone, but also in combination with oxLDL, significantly increased the lipid accumulation in THP-1 MΦ; a reverse effect was detected in siGDF-15 MΦ. Western-blot analyses and confocal laser scanning microscopy showed an increase of Atg5, Atg12/Atg5 protein complex and p62 protein in THP-1 MΦ co-incubated with rGDF-15 and oxLDL, as well as an increase of p62 accumulation compared to rGDF-15-treated MΦ. Vice versa, siGDF-15 MΦ showed a reduced p62 accumulation compared to nsiGDF-15 MΦ. The present study indicates that GDF-15, especially in combination with oxLDL, regulates the expression of autophagy-relevant proteins (p62, Atg5 and Atg12/Atg5 protein complex) and p62 accumulation in human MΦ.

CONCLUSIONS

GDF-15, in combination with oxLDL, impairs autophagic processes with consequences for lipid homeostasis in human MΦ, indicating its novel important pathophysiological role in atherosclerotic plaque development and progression.

Shear Stress in Autophagy and Its Possible Mechanisms in the Process of Atherosclerosis

Autophagy can eliminate harmful components and maintain cellular homeostasis in response to a series of extracellular insults in eukaryotes. More and more studies show that autophagy plays vital roles in the development of atherosclerosis. Atherosclerosis is a multifactorial disease and shear stress acts as a key role in its process. Understanding the role of shear stress in autophagy may offer insight into atherosclerosis therapies, especially emerging targeted therapy. In this article, we retrospect related studies to summarize the present comprehension of the association between autophagy and atherosclerosis onset and progression.

Tetrandrine inhibits migration and invasion of human renal cell carcinoma by regulating Akt/NF-κB/MMP-9 signaling

Renal cell carcinoma (RCC) is known as one of the most lethal malignancies in the urological system because of its high incidence of metastasis. Tetrandrine (Tet), a traditional Chinese herbal medicine, exerts a potent anti-cancer effect in a variety of cancer cells. However, the anti-metastatic effect of Tet and its possible mechanism in RCC is still unclear. The present study revealed that Tet significantly suppressed the migration and invasion of RCC 786-O and 769-P cells in vitro. Mechanistically, the protein levels of matrix metalloproteinases 9 (MMP-9), phosphorylated PI3K, PDK1, Akt and NF-κB were markedly reduced after Tet treatment. Moreover, co-treatment with LY294002 (PI3K inhibitor) could further enhance the Tet-inhibited migration and invasion, and the NF-κB and MMP-9 protein levels were further decreased. Similar results were observed after PDTC (NF-κB inhibitor) co-treatment. Conversely, SC79, an Akt activator, could partially reverse the anti-metastatic effects of Tet, accompanied by the restoration of NF-κB and MMP-9 protein levels. In conclusion, the current results indicated that Tet inhibited migration and invasion of RCC partially by regulating Akt/NF-κB/MMP-9 signaling pathway, suggesting that Tet may be a potential therapeutic candidate against metastatic RCC.