Nucleolin regulates the proliferation of vascular smooth muscle cells in atherosclerotic via Aurora B

Myogenic Anti-Nucleolin Aptamer iSN04 Inhibits Proliferation and Promotes Differentiation of Vascular Smooth Muscle Cells

De-differentiation and subsequent increased proliferation and inflammation of vascular smooth muscle cells (VSMCs) is one of the mechanisms of atherogenesis. Maintaining VSMCs in a contractile differentiated state is therefore a promising therapeutic strategy for atherosclerosis. We have reported the 18-base myogenetic oligodeoxynucleotide, iSN04, which serves as an anti-nucleolin aptamer and promotes skeletal and myocardial differentiation. The present study investigated the effect of iSN04 on VSMCs because nucleolin has been reported to contribute to VSMC de-differentiation under pathophysiological conditions. Nucleolin is localized in the nucleoplasm and nucleoli of both rat and human VSMCs. iSN04 without a carrier was spontaneously incorporated into VSMCs, indicating that iSN04 would serve as an anti-nucleolin aptamer. iSN04 treatment decreased the ratio of 5-ethynyl-2'-deoxyuridine (EdU)-positive proliferating VSMCs and increased the expression of α-smooth muscle actin, a contractile marker of VSMCs. iSN04 also suppressed angiogenesis of mouse aortic rings ex vivo, which is a model of pathological angiogenesis involved in plaque formation, growth, and rupture. These results demonstrate that antagonizing nucleolin with iSN04 preserves VSMC differentiation, providing a nucleic acid drug candidate for the treatment of vascular disease.

Targeting Oncostatin M Receptor to Attenuate Carotid Artery Plaque Vulnerability in Hypercholesterolemic Microswine

Atherosclerosis is a chronic inflammatory disease that leads to acute embolism via the formation of atherosclerotic plaques. Plaque formation is first induced by fatty deposition along the arterial intima. Inflammation, bacterial infection, and the released endotoxins can lead to dysfunction and phenotypic changes of vascular smooth muscle cells (VSMCs), advancing the plaque from stable to unstable form and prone to rupture. Stable plaques are characterized by increased VSMCs and less inflammation while vulnerable plaques develop due to chronic inflammation and less VSMCs. Oncostatin M (OSM), an inflammatory cytokine, plays a role in endothelial cells and VSMC proliferation. This effect of OSM could be modulated by p27KIP1, a cyclin-dependent kinase (CDK) inhibitor. However, the role of OSM in plaque vulnerability has not been investigated. To better understand the role of OSM and its downstream signaling including p27KIP1 in plaque vulnerability, we characterized the previously collected carotid arteries from hyperlipidemic Yucatan microswine using hematoxylin and eosin stain, Movat Pentachrome stain, and gene and protein expression of OSM and p27KIP1 using immunostaining and real-time polymerase chain reaction. OSM and p27KIP1 expression in carotid arteries with angioplasty and treatment with either scrambled peptide or LR12, an inhibitor of triggering receptor expressed on myeloid cell (TREM)-1, were compared between the experimental groups and with contralateral carotid artery. The results of this study elucidated the presence of OSM and p27KIP1 in carotid arteries with plaque and their association with arterial plaque and vulnerability. The findings suggest that targeting OSM and p27KIP1 axis regulating VSMC proliferation may have therapeutic significance to stabilize plaque.

Musashi-2 binds with Fbxo6 to induce Rnaset2 ubiquitination and chemokine signaling pathway during vascular smooth muscle cell phenotypic switch in atherosclerosis

OBJECTIVE

The objective of this study is to determine how Musashi-2 (MSI2) affects vascular smooth muscle cell (VSMC) phenotypic switch and contributes to atherosclerosis (AS).

METHODS

Primary mouse VSMCs were transfected with MSI2 specific siRNA and treated with platelet-derived growth factor-BB (PDGF-BB). The proliferation, cell-cycle, and migration of VSMCs were determined by CCK-8, flow cytometry, wound healing, and transwell assays. Western blot and qRT-PCR were conducted to analyze the protein and mRNA expression. Moreover, the correlation between MSI2, Fbxo6, Rnaset2, and chemokine signaling was predicted and verified using RNAct database, KEGG, wiki, RNA-binding protein immunoprecipitation and co-immunoprecipitation. Moreover, H&E and Oil Red O staining were employed for assessing necrotic core and lipid accumulation in AS mouse aorta tissues. The numbers of B lymphocytes and monocytes, and the levels of triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), and low-density lipoprotein cholesterol (LDL-C) in AS mice blood were investigated using flow cytometry and corresponding commercial kits, respectively.

RESULTS

MSI2 was up-regulated in the PDGF-BB-treated VSMCs. Knockdown of MSI2 inhibited VSMC proliferation, cell-cycle, and migration. Moreover, MSI2 regulated VSMC phenotypic switch through binding with Fbxo6 to induce Rnaset2 ubiquitination. MSI2 knockdown inhibited chemokine signaling via regulating Fbxo6/Rnaset2 axis. In AS mice, knockdown of MSI2 inhibited the formation of necrotic core and atherosclerotic plaque, and inhibited chemokine signaling via regulating Fbxo6/Rnaset2 axis.

CONCLUSION

Our findings demonstrated that MSI2 could bind with Fbxo6 to induce Rnaset2 ubiquitination and the activation of chemokine signaling pathway during VSMC phenotypic switch in AS.

NUCLEOLIN PROMOTES AUTOPHAGY THROUGH PGC-1Α IN LPS-INDUCED MYOCARDIAL INJURY

ABSTRACT

As a multifunctional protein, nucleolin can participate in a variety of cellular processes. Nucleolin also has multiple protective effects on heart disease. Previous studies have shown that nucleolin could not only resist oxidative stress damage and inflammatory damage, but also regulate autophagy to play a protective role in cardiac ischemia. However, the specific mechanism has not been fully elucidated in LPS-induced myocardial injury. Therefore, the aim of this study is to explore the underlying mechanism by which nucleolin regulates autophagy to protect against LPS-induced myocardial injury in vivo and in vitro . In our study, we found that nucleolin could bind to PGC-1α, and we predicted that this interaction could promote autophagy and played a role in inhibiting cardiomyocyte apoptosis. Downregulation of nucleolin in H9C2 cells resulted in decreased autophagy and increased cell apoptosis during LPS-induced myocardial injury, while upregulation of PGC-1α had the opposite protective effect. Upregulation of nucleolin expression in cardiomyocytes could increase the level of autophagy during LPS-induced myocardial injury. In contrast, interference with PGC-1α expression resulted in a decrease in the protective effect of nucleolin, leading to reduced autophagy and thus increasing apoptosis. By using tandem fluorescent-tagged LC3 autophagic flux detection system, we observed autophagic flux and determined that PGC-1α interference could block autophagic lysosomal progression. We further tested our hypothesis in the nucleolin cardiac-specific knockout mice. Finally, we also found that inhibition of autophagy can reduce mitochondrial biogenesis as well as increase apoptosis, which demonstrated the importance of autophagy. Therefore, we can speculate that nucleolin can protect LPS-induced myocardial injury by regulating autophagy, and this protective effect may be mediated by the interaction with PGC-1α, which can positively regulate the ULK1, an autophagy-related protein. Our study provides a new clue for the cardioprotective effect of nucleolin, and may provide new evidence for the treatment of LPS-induced myocardial injury through the regulation of autophagy.

Regulation of oxidized LDL-induced proliferation and migration in human vascular smooth muscle cells by a novel circ_0007478/miR-638/ROCK2 ceRNA network

BACKGROUND

Circular RNAs (circRNAs) have been implicated in the pathogenesis of atherosclerosis (AS) and the migration and proliferation of vascular smooth muscle cells (VSMCs) under oxidized low-density lipoprotein (ox-LDL). Here, we defined the exact action of human circ_0007478 in VSMC migration and proliferation induced by ox-LDL.

METHODS

Human VSMCs (HVSMCs) were exposed to ox-LDL. Circ_0007478, microRNA (miR)-638, and rho-associated protein kinase 2 (ROCK2) levels were gauged by quantitative real-time PCR (qRT-PCR) and western blot. Cell viability and proliferation were assessed by MTT and EdU assays, respectively. Transwell assays were used to detect cell migration and invasion. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were used to evaluate the direct relationship between miR-638 and circ_0007478 or ROCK2.

RESULTS

Our data indicated that circ_0007478 expression was augmented in AS serum samples and ox-LDL-treated HVSMCs. Depletion of circ_0007478 attenuated HVSMC proliferation, migration, and invasion induced by ox-LDL. Mechanistically, circ_0007478 targeted miR-638 by directly pairing to miR-638. Reduction of miR-638 reversed the effects of circ_0007478 depletion on ox-LDL-evoked proliferation, migration, and invasion in HVSMCs. ROCK2 was a direct miR-638 target and miR-638-mediated inhibition of ROCK2 relieved ox-LDL-evoked HVSMC proliferation, migration, and invasion. Furthermore, circ_0007478 was identified as a competing endogenous RNA (ceRNA) for miR-638 to modulate ROCK2 expression.

CONCLUSION

Our present study establishes an undescribed ceRNA regulatory network, in which circ_0007478 targets miR-638 to upregulate ROCK2, thereby contributing to ox-LDL-induced proliferation and migration in HVSMCs.

Ribosome biogenesis in disease: new players and therapeutic targets

The ribosome is a multi-unit complex that translates mRNA into protein. Ribosome biogenesis is the process that generates ribosomes and plays an essential role in cell proliferation, differentiation, apoptosis, development, and transformation. The mTORC1, Myc, and noncoding RNA signaling pathways are the primary mediators that work jointly with RNA polymerases and ribosome proteins to control ribosome biogenesis and protein synthesis. Activation of mTORC1 is required for normal fetal growth and development and tissue regeneration after birth. Myc is implicated in cancer development by enhancing RNA Pol II activity, leading to uncontrolled cancer cell growth. The deregulation of noncoding RNAs such as microRNAs, long noncoding RNAs, and circular RNAs is involved in developing blood, neurodegenerative diseases, and atherosclerosis. We review the similarities and differences between eukaryotic and bacterial ribosomes and the molecular mechanism of ribosome-targeting antibiotics and bacterial resistance. We also review the most recent findings of ribosome dysfunction in COVID-19 and other conditions and discuss the consequences of ribosome frameshifting, ribosome-stalling, and ribosome-collision. We summarize the role of ribosome biogenesis in the development of various diseases. Furthermore, we review the current clinical trials, prospective vaccines for COVID-19, and therapies targeting ribosome biogenesis in cancer, cardiovascular disease, aging, and neurodegenerative disease.

Tribulus terrestris L. extract ameliorates atherosclerosis by inhibition of vascular smooth muscle cell proliferation in ApoE-/- mice and A7r5 cells via suppression of Akt/MEK/ERK signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Atherosclerosis (AS) is one of major threatens of death worldwide, and vascular smooth muscle cell (VSMC) proliferation is an important characteristic in the progression of AS. Tribulus terrestris L. is a well-known Chinese Materia Medica for treating skin pruritus, vertigo and cardiovascular diseases in traditional Chinese medicine. However, its anti-AS activity and inhibition effect on VSMC proliferation are not fully elucidated.

AIMS

We hypothesize that the furostanol saponins enriched extract (FSEE) of T. terrestris L. presents anti-AS effect by inhibition of VSMC proliferation. The molecular action mechanism underlying the anti-VSMC proliferation effect of FSEE is also investigated.

MATERIALS AND METHODS

Apolipoprotein-E deficient (ApoE^-/-) mice and rat thoracic smooth muscle cell A7r5 were employed as the in vivo and in vitro models respectively to evaluate the anti- AS and VSMC proliferation effects of FSEE. In ApoE^-/- mice, the amounts of total cholesterol, triglyceride, low density lipoprotein and high density lipoprotein in serum were measured by commercially available kits. The size of atherosclerotic plaque was observed by hematoxylin & eosin staining. The protein expressions of α-smooth muscle actin (α-SMA) and osteopontin (OPN) in the plaque were examined by immunohistochemistry. In A7r5 cells, the cell viability and proliferation were tested by MTT and Real Time Cell Analysis assays. The cell migration was evaluated by wound healing assay. Propidium iodide staining followed by flow cytometry was used to analyze the cell cycle progression. The expression of intracellular total and phosphorylated proteins including protein kinase B (Akt) and mitogen-activated protein kinases (MAPKs), such as mitogen-activated extracellular signal-regulated kinase (MEK), extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), were detected by western blotting analysis.

RESULTS

FSEE significantly reduced the area of atherosclerotic plaque in high-fat diet-fed ApoE^-/- mice. And FSEE increased the protein expression level of α-SMA and decreased the level of OPN in atherosclerotic plaque, which revealed the inhibition of VSMC phenotype switching and proliferation. In A7r5 cells, FSEE suppressed fetal bovine serum (FBS) or oxidized low density lipoprotein (oxLDL)-triggered VSMC proliferation and migration in a concentration dependent manner. FSEE protected against the elevation of cell numbers in S phase induced by FBS or oxLDL and the reduction of cell numbers in G₀/G₁ phase induced by oxLDL. Moreover, the phosphorylation of Akt and MAPKs including MEK, ERK and JNK could be facilitated by FBS or oxLDL, while co-treatment of FSEE attenuated the phosphorylation of Akt induced by oxLDL as well as the phosphorylation of MEK and ERK induced by FBS. In addition, (25R)-terrestrinin B (JL-6), which was the main ingredient of FSEE, and its potential active pharmaceutical ingredients tigogenin (Tigo) and hecogenin (Heco) also significantly attenuated FBS or oxLDL-induced VSMC proliferation in A7r5 cells.

CONCLUSION

FSEE presents potent anti- AS and VSMC proliferation activities and the underlying mechanism is likely to the suppression of Akt/MEK/ERK signaling. The active components of FSEE are JL-6 and its potential active pharmaceutical ingredients Tigo and Heco. So, FSEE and its active compounds may be potential therapeutic drug candidates for AS.

Cancer Stem Cells and Nucleolin as Drivers of Carcinogenesis

Cancer, one of the most mortal diseases worldwide, is characterized by the gain of specific features and cellular heterogeneity. Clonal evolution is an established theory to explain heterogeneity, but the discovery of cancer stem cells expanded the concept to include the hierarchical growth and plasticity of cancer cells. The activation of epithelial-to-mesenchymal transition and its molecular players are widely correlated with the presence of cancer stem cells in tumors. Moreover, the acquisition of certain oncological features may be partially attributed to alterations in the levels, location or function of nucleolin, a multifunctional protein involved in several cellular processes. This review aims at integrating the established hallmarks of cancer with the plasticity of cancer cells as an emerging hallmark; responsible for tumor heterogeneity; therapy resistance and relapse. The discussion will contextualize the involvement of nucleolin in the establishment of cancer hallmarks and its application as a marker protein for targeted anticancer therapies