CHOP Increases TRIB3-Dependent miR-208 Expression to Potentiate Vascular Smooth Muscle Cell Proliferation and Migration by Downregulating TIMP3 in Atherosclerosis

Diverse functions of Tribbles homolog 3 in cancers and its potential as a therapeutic target

Currently, cancer is the second leading cause of death worldwide, and potential targeted drugs and molecular pathways for cancer development and progression have been a hot research topic worldwide. In recent years, the importance of the kinase superfamily in diseases has been well demonstrated by studies on various molecular mechanisms of kinases and the successful application of their inhibitors in diseases. Pseudokinases are members of the kinase superfamily, which have been increasingly documented to play a crucial role in cancers year after year. As a member of pseudokinases, tribbles homolog 3 (TRIB3) also exerts diverse functions in different cancers through different interacting proteins and molecular pathways, especially in tumor immunity, stemness, drug resistance, metabolism, and autophagy. In addition, peptide drugs targeting TRIB3 have high specificity in preclinical studies, which shows great promise for TRIB3 application in diseases including cancers. In this review, we dissect diverse functions played by TRIB3 in different cancers, describing the underlying mechanisms in detail. Notably, inhibitors and agonists currently available for TRIB3 are discussed, indicating the potential for TRIB3 as a therapeutic target.

Hawthorn leaf flavonoids alleviate the deterioration of atherosclerosis by inhibiting SCAP-SREBP2-LDLR pathway through sPLA2-ⅡA signaling in macrophages in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Hawthorn leaves are a combination of the dried leaves of the Rosaceae plants, i.e., Crataegus pinnatifida Bge. or Crataegus pinnatifida Bge. var. major N. E. Br., is primarily cultivated in East Asia, North America, and Europe. hawthorn leaf flavonoids (HLF) are the main part of extraction. The HLF have demonstrated potential in preventing hypertension, inflammation, hyperlipidemia, and atherosclerosis. However, the potential pharmacological mechanism behind its anti-atherosclerotic effect has yet to be explored.

AIM OF THE STUDY

The in vivo and in vitro effects of HLF on lipid-mediated foam cell formation were investigated, with a specific focus on the levels of secreted phospholipase A2 type IIA (sPLA2-II A) in macrophage cells.

MATERIALS AND METHODS

The primary constituents of HLF were analyzed using ultra-high performance liquid chromatography and liquid chromatography-tandem mass spectrometry. In vivo, HLF, at concentrations of 5 mg/kg, 20 mg/kg, and 40 mg/kg, were administered to apolipoprotein E knockout mice (ApoE-/-) fed by high-fat diet (HFD) for 16 weeks. Aorta and serum samples were collected to identify lesion areas and lipids through mass spectrometry analysis to dissect the pathological process. RAW264.7 cells were incubated with oxidized low-density lipoprotein (ox-LDL) alone, or ox-LDL combined with different doses of HLF (100, 50, and 25 μg/ml), or ox-LDL plus 24-h sPLA2-IIA inhibitors, for cell biology analysis. Lipids and inflammatory cytokines were detected using biochemical analyzers and ELISA, while plaque size and collagen content of plaque were assessed by HE and the Masson staining of the aorta. The lipid deposition in macrophages was observed by Oil Red O staining. The expression of sPLA2-IIA and SCAP-SREBP2-LDLR was determined by RT-qPCR and Western blot analysis.

RESULTS

The chemical profile of HLF was studied using UPLC-Q-TOF-MS/MS, allowing the tentative identification of 20 compounds, comprising 1 phenolic acid, 9 flavonols and 10 flavones, including isovitexin, vitexin-4″-O-glucoside, quercetin-3-O-robibioside, rutin, vitexin-2″-O-rhamnoside, quercetin, etc. HLF decreased total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein cholesterol (non-HDL-C) levels in ApoE-/- mice (P < 0.05), reduced ox-LDL uptake, inhibited level of inflammatory factors, such as IL-6, IL-8, TNF-α, and IL-1ꞵ (P < 0.001), and alleviated aortic plaques with a thicker fibrous cap. HLF effectively attenuated foam cell formation in ox-LDL-treated RAW264.7 macrophages, and reduced levels of intracellular TC, free cholesterol (FC), cholesteryl ester (CE), IL-6, TNF-α, and IL-1β (P < 0.001). In both in vivo and in vitro experiments, HLF significantly downregulated the expression of sPLA2-IIA, SCAP, SREBP2, LDLR, HMGCR, and LOX-1 (P < 0.05). Furthermore, sPLA2-IIA inhibitor effectively mitigated inflammatory release in RAW264.7 macrophages and regulated SCAP-SREBP2-LDLR signaling pathway by inhibiting sPLA2-IIA secretion (P < 0.05).

CONCLUSION

HLF exerted a protective effect against atherosclerosis through inhibiting sPLA2-IIA to diminish SCAP-SREBP2-LDLR signaling pathway, to reduce LDL uptake caused foam cell formation, and to slow down the progression of atherosclerosis in mice.

β-carotene targets IP3R/GRP75/VDAC1-MCU axis to renovate LPS-induced mitochondrial oxidative damage by regulating STIM1

Endoplasmic reticulum (ER) and mitochondria are the main sites for the storage and regulation of Ca2+ homeostasis. An imbalance of Ca2+ homeostasis can cause ER stress and mitochondrial dysfunction, thereby inducing apoptosis. The store-operated calcium entry (SOCE) is the main channel for extracellular calcium influx. Mitochondria-associated endoplasmic reticulum (MAM) is an important agent for Ca2+ transfer from the ER to the mitochondria. Therefore, regulation of SOCE and MAMs has potential therapeutic value for disease prevention and treatment. In this study, bovine mammary epithelial cells (BMECs) and mice were used as models to explore the mechanisms of β-carotene to relieve ER stress and mitochondrial dysfunction. BAPTA-AM, EGTA (Ca2+ inhibitor), and BTP2 (SOCE channel inhibitor) alleviated ER stress and mitochondrial oxidative damage induced by increased intracellular Ca2+ levels after lipopolysaccharide (LPS) stimulation. Furthermore, inhibition of ER stress by 4-PBA (ER stress inhibitor), 2-APB (IP3R inhibitor), and ruthenium red (mitochondrial calcium uniporter (MCU) inhibitor) restored mitochondrial function by reducing mitochondrial ROS. Our data also confirm that β-carotene targeted STIM1 and IP3R channels to repair LPS-induced ER stress and mitochondrial disorders. Consistent with the in vitro study, in vito experiments in mice further showed that β-carotene attenuated LPS-induced ER stress and mitochondrial oxidative damage by inhibiting the expression of STIM1 and ORAI1, and reducing the level of Ca2+ in mouse mammary glands. Therefore, ER stress-mitochondrial oxidative damage mediated by the STIM1-ER-IP3R/GRP75/VDAC1-MCU axis plays an vital role in the development of mastitis. Our results provided novel ideas and therapeutic targets for the prevention and treatment of mastitis.

Functional polymorphism in miR-208 is associated with increased risk for ischemic stroke

BACKGROUND

The miR-208 gene is one of the microRNAs now under active studies, and has been found to play significant roles in an array of cardiovascular diseases. Nevertheless, until now, no studies have examined the relationship between the susceptibility to ischemic stroke (IS) and genetic variations in miR-208. This study explored the association between the miR-208 polymorphisms (rs178642, rs8022522, and rs12894524) and the risk of IS.

METHODS

A total of 205 cases of IS and 211 control subjects were included. The SNPscans genotyping test was employed to determine the genotypes of the three polymorphisms.

RESULTS

Significant correlation was observed between rs8022522 polymorphism and risk of IS on the basis of analyses of genotypes, models and alleles (GA vs. GG: adjusted OR = 2.159, 95% CI: 1.052-4.430, P = 0. 036; AA vs. GG: adjusted OR = 5.154, 95% CI: 1.123-23.660, P = 0.035; dominant model: adjusted OR = 1.746, 95% CI, 1.075-2.838, P = 0.025; G vs. A: adjusted OR = 2.451, 95% CI: 1.374-4.370, P = 0.002).

CONCLUSIONS

The rs8022522 polymorphism of the miR-208 gene is significantly associated with an elevated risk of ischemic stroke in Chinese.

Xbp1s-Ddit3 promotes MCT-induced pulmonary hypertension

Pulmonary hypertension (PH) is a life-threatening disease characterized by vascular remodeling. Exploring new therapy target is urgent. The purpose of the present study is to investigate whether and how spliced x-box binding protein 1 (xbp1s), a key component of endoplasmic reticulum stress (ERS), contributes to the pathogenesis of PH. Forty male SD rats were randomly assigned to four groups: Control, Monocrotaline (MCT), MCT+AAV-CTL (control), and MCT+AAV-xbp1s. The xbp1s protein levels were found to be elevated in lung tissues of the MCT group. Intratracheal injection of adeno-associated virus serotype 1 carrying xbp1s shRNA (AAV-xbp1s) to knock down the expression of xbp1s effectively ameliorated the MCT-induced elevation of right ventricular systolic pressure (RVSP), total pulmonary resistance (TPR), right ventricular hypertrophy and medial wall thickness of muscularized distal pulmonary arterioles. The abnormally increased positive staining rates of proliferating cell nuclear antigen (PCNA) and Ki67 and decreased positive staining rates of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) in pulmonary arterioles were also reversed in the MCT+AAV-xbp1s group. For mechanistic exploration, bioinformatics prediction of the protein network was performed on the STRING database, and further verification was performed by qRT-PCR, Western blots and co-immunoprecipitation (Co-IP). DNA damage-inducible transcript 3 (Ddit3) was identified as a downstream protein that interacted with xbp1s. Overexpression of Ddit3 restored the decreased proliferation, migration and cell viability caused by silencing of xbp1s. The protein level of Ddit3 was also highly consistent with xbp1s in the animal model. Taken together, our study demonstrated that xbp1s-Ddit3 may be a potential target to interfere with vascular remodeling in PH.

Extracellular matrix: paving the way to the newest trends in atherosclerosis

PURPOSE OF REVIEW

The extracellular matrix (ECM) is critical for all aspects of vascular pathobiology. In vascular disease the balance of its structural components is shifted. In atherosclerotic plaques there is in fact a dynamic battle between stabilizing and proinflammatory responses. This review explores the most recent strides that have been made to detail the active role of the ECM - and its main binding partners - in driving atherosclerotic plaque development and destabilization.

RECENT FINDINGS

Proteoglycans-glycosaminoglycans (PGs-GAGs) synthesis and remodelling, as well as elastin synthesis, cross-linking, degradation and its elastokines potentially affect disease progression, providing multiple steps for potential therapeutic intervention and diagnostic targeted imaging. Of note, GAGs biosynthetic enzymes modulate the phenotype of vascular resident and infiltrating cells. In addition, while plaque collagen structure exerts very palpable effects on its immediate surroundings, a new role for collagen is also emerging on a more systemic level as a biomarker for cardiovascular disease as well as a target for selective drug-delivery.

SUMMARY

The importance of studying the ECM in atherosclerosis is more and more acknowledged and various systems are being developed to visualize, target and mimic it.