LC3B, a Protein That Serves as an Autophagic Marker, Modulates Angiotensin II-induced Myocardial Hypertrophy

CUL1-neddylation contributes to K29-linked ubiquitination on p27 for autophagic degradation in sorafenib-resistant liver cancer

Sorafenib has demonstrated great efficacy in liver cancer, however, its application as first-line treatment has been hampered due to the emerging drug resistance. This study is aimed to investigate the mechanism underlying acquired sorafenib resistance in liver cancer. Based on GSE109211 and TCGA datasets, bioinformatics analysis was conducted to find the potential genes implicated in the sorafenib resistance in liver cancer. mCherry-/eGFP-LC3B dual-fluorescent system was used to assess autophagic state. Wild and mutant types of HA-labeled ubiquitin (K27, K29, K33, K48, K63, K29R and K48R) were used to identify the type of polyubiquitin chains added to p27 by CUL1. Herein, we identified that F-box protein (SCF) ubiquitin ligase complexes (CUL1 and SKP2) and NEDD8 were highly expressed in sorafenib-resistant tissues using both the public data and clinical samples. NEDD8-mediated CUL1 neddylation enhanced SCF ubiquitin ligase complex to target p27 and subsequently linked K29-linked polyubiquitin chains to p27. Furthermore, NBR1 facilitated the degradation of ubiquitinated p27 protein by enhancing autophagy flux. Knocking down of CUL1 could prevent ubiquitination- and autophagy-mediated p27 protein degradation. The resistance to sorafenib was suppressed with CUL1 knockdown both in vitro and in vivo. In conclusion, our findings indicated that blocking neddylation or autophagy can restore drug sensitivity, thus providing a potential strategy for overcoming sorafenib resistance in the future.

Evaluation of the Leaves and Seeds of Cucurbitaceae Plants as a New Source of Bioactive Compounds for Colorectal Cancer Prevention and Treatment

BACKGROUND/OBJECTIVES

The Cucurbitaceae family represents an important source of bioactive compounds with antioxidant, antimicrobial, anti-inflammatory and antitumor activities. This study aims to investigate the potential application of Cucurbitaceae leaves and seed extracts to prevent and treat colorectal cancer (CRC).

METHODS

Four extracts (ethanol extracts and protein extracts and hydrolysates) from the leaves and seeds of cucurbits were tested in T-84, HCT-15 and HT-29 CRC cells. The antitumor, antiangiogenic, antioxidant and chemopreventive potentials and bioactive composition of the active extracts were characterized.

RESULTS

Cold ethanolic extracts from the leaves and seeds of two interspecific Cucurbita genera (CLU01002 and COK01001) exhibited potent antiproliferative, specific and non-hepatotoxic activity against CRC cell lines, with a slight synergistic effect in combination with oxaliplatin. This antitumor activity was related to G2/M cell cycle arrest, the extrinsic apoptosis pathway, cytokinesis inhibition and autophagy. The extracts also inhibited tumor clonogenicity and angiogenesis, and modulated cancer stem cell (CSC) gene expression, as well as expressing antioxidant and chemopreventive cellular capabilities. Finally, phenolic and cucurbitane-type triterpenoid compounds (pengxianencins and cucurbitacins) were tentatively identified in the active extracts by UPLC-MS analysis and bioguided fractionation.

CONCLUSIONS

Extracts from leaves the and seeds of two interspecific Cucurbita genera (CLU01002 and COK01001) may contribute to the improvement of prevention and treatment strategies for CRC patients.

Modeling Parkinson's disease pathology in human dopaminergic neurons by sequential exposure to α-synuclein fibrils and proinflammatory cytokines

Lewy bodies (LBs), α-synuclein-enriched intracellular inclusions, are a hallmark of Parkinson's disease (PD) pathology, yet a cellular model for LB formation remains elusive. Recent evidence indicates that immune dysfunction may contribute to the development of PD. In this study, we found that induced pluripotent stem cell (iPSC)-derived human dopaminergic (DA) neurons form LB-like inclusions after treatment with α-synuclein preformed fibrils (PFFs) but only when coupled to a model of immune challenge (interferon-γ or interleukin-1β treatment) or when co-cultured with activated microglia-like cells. Exposure to interferon-γ impairs lysosome function in DA neurons, contributing to LB formation. The knockdown of LAMP2 or the knockout of GBA in conjunction with PFF administration is sufficient for inclusion formation. Finally, we observed that the LB-like inclusions in iPSC-derived DA neurons are membrane bound, suggesting that they are not limited to the cytoplasmic compartment but may be formed due to dysfunctions in autophagy. Together, these data indicate that immune-triggered lysosomal dysfunction may contribute to the development of PD pathology.

Downregulating miR-432-5p exacerbates adriamycin-induced cardiotoxicity via activating the RTN3 signaling pathway

BACKGROUND

Adriamycin (ADR) is a widely used chemotherapy drug in clinical practice and it causes toxicity in the myocardium affecting its clinical use. miR-432-5p is a miRNA primarily expressed in myocardial cells and has a protective effect in the myocardium. We aim to explore the protective effect of miR-432-5p on ADR-caused impaired mitochondrial ATP metabolism and endoplasmic reticulum stress (ERs).

METHOD

The primary cardiomyocytes were obtained from neonatal mice and the ADR was added to cells, meanwhile, a mice model was constructed through intravenous ADR challenge, and expression levels of miR-432-5p were examined. Subsequently, the miR-432-5p was introduced in vitro and in vivo to explore its effect on the activity of mitochondrial ATP synthesis, autophagy, and ER stress. The bioinformatics analysis was performed to explore the target of miR-432-5p.

RESULTS

ADR decreased the expression of miR-432-5p in cardiomyocytes. It also decreases mitochondrial ATP production and activates the ER stress pathway by increasing the expression of LC3B, Beclin 1, cleaved caspase 3, and induces cardiac toxicity. miR-432-5p exogenous supplementation can reduce the cardiotoxicity caused by ADR, and its protective effect on cardiomyocytes depends on the down-regulation of the RTN3 signaling pathway in ER.

CONCLUSION

ADR can induce the low expression of miR-432-5p, and activate the RTN3 pathway in ER, increase the expression of LC3B, Beclin 1, cleaved caspase 3, CHOP, and RTN3, and induce cardiac toxicity.

Sacubitril/valsartan mitigates cardiac remodeling, systolic dysfunction, and preserves mitochondrial quality in a rat model of mitral regurgitation

Sacubitril/valsartan (SAC/VAL), an angiotensin receptor blocker-neprilysin inhibitor, has been widely used to treat several types of heart failure. Nevertheless, the effects of drugs in mitral regurgitation patients, from the molecular level to therapeutic effects, remain unclear. This study investigates the roles of SAC/VAL on cardiac function, mitochondrial quality, autophagy, mitophagy, and natriuretic peptides in a rat model of chronic mitral regurgitation. Male Sprague-Dawley rats underwent MR induction (n = 16) and sham surgeries (n = 8). Four weeks post-surgery confirmed MR rats were randomly divided into MR (n = 8) and SAC/VAL (n = 8) groups. The SAC/VAL group was administered SAC/VAL, whereas the MR and the sham rats received vehicle via oral gavage daily for 8 weeks. Cardiac geometry, function, and myocardial fibrosis were assessed by echocardiography and histopathology. Spectrophotometry and real-time PCR were performed to assess the pharmacological effects on mitochondrial quality, autophagy, mitophagy, and natriuretic peptides. MR rats demonstrated significant left heart dilation and left ventricular systolic dysfunction compared with the sham group, which could be significantly improved by SAC/VAL. In addition, SAC/VAL significantly reduced myocardial cardiac remodeling and fibrosis in MR rats. SAC/VAL improved the mitochondrial quality by attenuating mitochondrial reactive oxygen species production and mitochondrial depolarization compared with the MR group. Also, the upregulation of autophagy-related, mitophagy-related, and natriuretic peptide system gene expression in MR rats was attenuated by SAC/VAL treatment. In conclusion, this study demonstrated that SAC/VAL treatment could provide numerous beneficial effects in MR conditions, suggesting that this drug may be an effective treatment for MR.

AURKA, as a potential prognostic biomarker, regulates autophagy and immune infiltration in nasopharyngeal carcinoma

BACKGROUND

Dysfunction of Aurora A (AURKA) plays crucial role in tumorigenesis and development of many types of cancer. However, the role of AURKA in nasopharyngeal carcinoma (NPC) has not been investigated yet.

MATERIALS AND METHODS

Two independent NPC cohorts (GSE61218 and GSE102349) were enrolled from public database to investigate the expression level of AURKA between NPC and nasopharyngitis samples, the association of AURKA expression level with prognosis in NPC, and the potential mechanism of AURKA in NPC by using bioinformatics analyses. The expression level of AURKA protein in 62 paired NPC and nasopharyngitis tissues was evaluated by immunohistochemistry (IHC). Two NPC cell lines (SUNE-1 and CNE-2) were enrolled and the expression levels of AURKA in the NPC cells were inhibited by RNA interference. The expression levels of mRNAs were tested by qPCR and western-blotting. CCK-8 assay was applied to measure the cell growth. Cell migration was measured by using wound healing assays.

RESULTS

AURKA was highly expressed in NPC samples compared to nasopharyngitis samples in GSE61218, which was confirmed by IHC. High expression of AURKA was associated with worse prognosis in GSE102349. Notably, silencing of AURKA was associated with significantly decreased cell growth and migration in NPC. Moreover, we found that the differentially expressed genes between high and low AURKA expression groups in GSE102349 were majorly enriched in both autophagy-related and immune-related pathways. Additionally, the expression level of AURKA was associated with the expression levels of autophagy-related genes and the infiltration of immune cells.

CONCLUSION

AURKA overexpressed in NPC, which was associated with poor prognosis. Silencing of AURKA inhibited the proliferation and migration of NPC cells. Besides, AURKA might participate in the regulation of both autophagy and immunity in NPC.

Targeting the MicroRNA-490-3p-ATG4B-Autophagy Axis Relieves Myocardial Injury in Ischemia Reperfusion

We investigated the potential role of miR-490-3p in ischemia reperfusion (IR) injury. We first determined the expression of miR-490-3p and autophagy-related 4B cysteine (ATG4B) in IR. Then, to explore whether miR-490-3p would affect autophagy, apoptosis, and IR injury, we evaluated apoptosis, autophagy, and infarct size via gain- and loss-of-function experiments. Furthermore, we used adenovirus to enhance or inhibit the expression of ATG4B, and then measured autophagy, apoptosis, and IR injury. miR-490-3p was downregulated in the hearts during the process of IR, while ATG4B was upregulated. The inhibition of miR-490-3p or overexpression of ATG4B could promote the expression of LC3II, increase the autolysosomes, inhibit the expression of p62, and reduce infarct size. On all accounts, the inhibition of miR-490-3p could promote autophagy to reduce myocardial IR injury by upregulating ATG4B, a finding that provides new insights for the protective mechanism of autophagy in IR. Graphical Abstract.

Downregulation of miR-26b-5p, miR-204-5p, and miR-497-3p Expression Facilitates Exercise-Induced Physiological Cardiac Hypertrophy by Augmenting Autophagy in Rats

Exercise-induced autophagy is associated with physiological left ventricular hypertrophy (LVH), and a growing body of evidence suggests that microRNAs (miRNAs) can regulate autophagy-related genes. However, the precise role of miRNAs in exercise induced autophagy in physiological LVH has not been fully defined. In this study, we investigated the microRNA–autophagy axis in physiological LVH and deciphered the underlying mechanism using a rat swimming exercise model. Rats were assigned to sedentary control (CON) and swimming exercise (EX) groups; those in the latter group completed a 10-week swimming exercise without any load. For in vitro studies, H9C2 cardiomyocyte cell line was stimulated with IGF-1 for hypertrophy. We found a significant increase in autophagy activity in the hearts of rats with exercise-induced physiological hypertrophy, and miRNAs showed a high score in the pathway enriched in autophagy. Moreover, the expression levels of miR-26b-5p, miR-204-5p, and miR-497-3p showed an obvious increase in rat hearts. Adenovirus-mediated overexpression of miR-26b-5p, miR-204-5p, and miR-497-3p markedly attenuated IGF-1-induced hypertrophy in H9C2 cells by suppressing autophagy. Furthermore, miR-26b-5p, miR-204-5p, and miR-497-3p attenuated autophagy in H9C2 cells through targeting ULK1, LC3B, and Beclin 1, respectively. Taken together, our results demonstrate that swimming exercise induced physiological LVH, at least in part, by modulating the microRNA–autophagy axis, and that miR-26b-5p, miR-204-5p, and miR-497-3p may help distinguish physiological and pathological LVH.

Electric charge conversable drug liposomes enable to enhance treatment efficacy of breast cancer

Intrinsic drug resistance has been demonstrated in different types of breast cancer cells, leading to the recurrence of disease after treatment. Here, we report a functional drug liposome that enables electric charge conversion in the weak acidic milieu of cancer to enhance the treatment efficacy of different breast cancers. The functional drug liposomes were developed by encapsulating daunorubicin and rofecoxib, and modified with new functional material, D-alpha tocopherol acid succinate-polyethylene glycol-glutarate (TPGS1000-glutarate). The results demonstrated that the liposomes promoted the effects of cellular uptake and lysosomal escape, followed by targeting the mitochondria. Consequently, the electric charge conversable drug liposomes significantly enhanced the treatment efficacy by initiating a cascade of reactions through inducing autophagy and apoptosis in different breast cancer cells. In conclusion, the electric charge conversable drug liposomes enable to enhance treatment efficacy of different breast cancers, and hence the study could offer a broadly applicable strategy to enhance efficacy against heterogeneous and refractory cancer cells.

Dual-functional fluorescent molecular rotor for endoplasmic reticulum microviscosity imaging during reticulophagy

A dual functional fluorescent molecular rotor was developed to trigger intracellular ER autophagy and quantify the local viscosity variations by FLIM imaging.

New and revisited approaches to preserving the reperfused myocardium

Early coronary artery reperfusion improves outcomes for patients with ST-segment elevation myocardial infarction (STEMI), but morbidity and mortality after STEMI remain unacceptably high. The primary deficits seen in these patients include inadequate pump function, owing to rapid infarction of muscle in the first few hours of treatment, and adverse remodelling of the heart in the months that follow. Given that attempts to further reduce myocardial infarct size beyond early reperfusion in clinical trials have so far been disappointing, effective therapies are still needed to protect the reperfused myocardium. In this Review, we discuss several approaches to preserving the reperfused heart, such as therapies that target the mechanisms involved in mitochondrial bioenergetics, pyroptosis, and autophagy, as well as treatments that harness the cardioprotective properties of inhaled anaesthetic agents. We also discuss potential therapies focused on correcting the no-reflow phenomenon and its effect on healing and adverse left ventricular remodelling.

Current Evidence for a Role of Neuropeptides in the Regulation of Autophagy

Neuropeptides drive a wide diversity of biological actions and mediate multiple regulatory functions involving all organ systems. They modulate intercellular signalling in the central and peripheral nervous systems as well as the cross talk among nervous and endocrine systems. Indeed, neuropeptides can function as peptide hormones regulating physiological homeostasis (e.g., cognition, blood pressure, feeding behaviour, water balance, glucose metabolism, pain, and response to stress), neuroprotection, and immunomodulation. We aim here to describe the recent advances on the role exerted by neuropeptides in the control of autophagy and its molecular mechanisms since increasing evidence indicates that dysregulation of autophagic process is related to different pathological conditions, including neurodegeneration, metabolic disorders, and cancer.

The role of autophagy in angiotensin II-induced pathological cardiac hypertrophy

Pathological cardiac hypertrophy is associated with nearly all forms of heart failure. It develops in response to disorders such as coronary artery disease, hypertension and myocardial infarction. Angiotensin II (Ang II) has direct effects on the myocardium and promotes hypertension. Chronic elevation of Ang II can lead to pathological cardiac hypertrophy and cardiac failure. Autophagy is an important process in the pathogenesis of cardiovascular diseases. Under physiological conditions, autophagy is an essential homeostatic mechanism to maintain the global cardiac structure function by ridding damaged cells or unwanted macromolecules and organelles. Dysregulation of autophagy may play an important role in Ang II-induced cardiac hypertrophy although conflicting reports on the effects of Ang II on autophagy and cardiac hypertrophy exist. Some studies showed that autophagy activation attenuated Ang II-induced cardiac dysfunction. Others suggested that inhibition of the Ang II induced autophagy should be protective. The discrepancies may be due to different model systems and different signaling pathway involved. Ang II-induced cardiac hypertrophy may be alleviated through regulation of autophagy. This review focuses on Ang II to highlight the molecular targets and pathways identified in the prevention and treatment of Ang II-induced pathological cardiac hypertrophy by regulating autophagy.