Showing papers in "Journal of Cellular and Molecular Medicine in 2020"

Mitochondrial biogenesis: An update

Abstract: In response to the energy demand triggered by developmental signals and environmental stressors, the cells launch the mitochondrial biogenesis process. This is a self-renewal route, by which new mitochondria are generated from the ones already existing. Recently, considerable progress has been made in deciphering mitochondrial biogenesis-related proteins and genes that function in health and in pathology-related circumstances. However, an outlook on the intracellular mechanisms shared by the main players that drive mitochondrial biogenesis machinery is still missing. Here, we provide such a view by focusing on the following issues: (a) the role of mitochondrial biogenesis in homeostasis of the mitochondrial mass and function, (b) the signalling pathways beyond the induction/promotion, stimulation and inhibition of mitochondrial biogenesis and (c) the therapeutic applications aiming the repair and regeneration of defective mitochondrial biogenesis (in ageing, metabolic diseases, neurodegeneration and cancer). The review is concluded by the perspectives of mitochondrial medicine and research.

The ACE2 expression in Sertoli cells and germ cells may cause male reproductive disorder after SARS-CoV-2 infection.

Abstract: The serious coronavirus disease-2019 (COVID-19) was first reported in December 2019 in Wuhan, China COVID-19 is an infectious disease caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) Angiotensin converting enzyme 2(ACE2) is the cellular receptor for SARS-CoV-2 Considering the critical roles of testicular cells for the transmission of genetic information between generations, we analyzed single-cell RNA-sequencing (scRNA-seq) data of adult human testis The mRNA expression of ACE2 was expressed in both germ cells and somatic cells Moreover, the positive rate of ACE2 in testes of infertile men was higher than normal, which indicates that SARS-CoV-2 may cause reproductive disorders through pathway activated by ACE2 and the men with reproductive disorder may easily to be infected by SARS-CoV-2 The expression level of ACE2 was related to the age, and the mid-aged with higher positive rate than young men testicular cells Taken together, this research provides a biological background of the potential route for infection of SARS-CoV-2 and may enable rapid deciphering male-related reproductive disorders induced by COVID-19

An EMT-related gene signature for the prognosis of human bladder cancer.

Abstract: The transition from non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive bladder cancer (MIBC) is detrimental to bladder cancer (BLCA) patients. Here, we aimed to study the underlying mechanism of the subtype transition. Gene set variation analysis (GSVA) revealed the epithelial-mesenchymal transition (EMT) signalling pathway with the most positive correlation in this transition. Then, we built a LASSO Cox regression model of an EMT-related gene signature in BLCA. The patients with high risk scores had significantly worse overall survival (OS) and disease-free survival (DFS) than those with low risk scores. The EMT-related gene signature also performed favourably in the accuracy of prognosis and in the subtype survival analysis. Univariate and multivariate Cox regression analyses demonstrated that the EMT-related gene signature, pathological N stage and age were independent prognostic factors for predicting survival in BLCA patients. Furthermore, the predictive nomogram model was able to effectively predict the outcome of BLCA patients by appropriately stratifying the risk score. In conclusion, we developed a novel EMT-related gene signature that has tumour-promoting effects, acts as a negative independent prognostic factor and might facilitate personalized counselling and treatment in BLCA.

Curcumin alleviates oxidative stress and inhibits apoptosis in diabetic cardiomyopathy via Sirt1-Foxo1 and PI3K-Akt signalling pathways

Abstract: Diabetes is a disorder of glucose metabolism, and over 90% are type 2 diabetes. Diabetic cardiomyopathy (DCM) is one of the type 2 diabetes complications, usually accompanied by changes in myocardial structure and function, together with cardiomyocyte apoptosis. Our study investigated the effect of curcumin on regulating oxidative stress (OS) and apoptosis in DCM. In vivo, diabetes was induced in an experimental rat model by streptozoticin (STZ) together with high-glucose and high-fat (HG/HF) diet feeding. In vitro, H9c2 cardiomyocytes were cultured with high-glucose and saturated free fatty acid palmitate. Curcumin was orally or directly administered to rats or cells, respectively. Streptozoticin -induced diabetic rats showed metabolism abnormalities and elevated markers of OS (superoxide dismutase [SOD], malondialdehyde [MDA], gp91phox , Cyt-Cyto C), enhanced cell apoptosis (Bax/Bcl-2, Cleaved caspase-3, TUNEL-positive cells), together with reduced Akt phosphorylation and increased Foxo1 acetylation. Curcumin attenuated the myocardial dysfunction, OS and apoptosis in the heart of diabetic rats. Curcumin treatment also enhanced phosphorylation of Akt and inhibited acetylation of Foxo1. These results strongly suggest that apoptosis was increased in the heart of diabetic rats, and curcumin played a role in diabetic cardiomyopathy treatment by modulating the Sirt1-Foxo1 and PI3K-Akt pathways.

Mitochondrial and mitochondrial-independent pathways of myocardial cell death during ischaemia and reperfusion injury.

Abstract: Acute myocardial infarction causes lethal injury to cardiomyocytes during both ischaemia and reperfusion (IR). It is important to define the precise mechanisms by which they die in order to develop strategies to protect the heart from IR injury. Necrosis is known to play a major role in myocardial IR injury. There is also evidence for significant myocardial death by other pathways such as apoptosis, although this has been challenged. Mitochondria play a central role in both of these pathways of cell death, as either a causal mechanism is the case of mitochondrial permeability transition leading to necrosis, or as part of the signalling pathway in mitochondrial cytochrome c release and apoptosis. Autophagy may impact this process by removing dysfunctional proteins or even entire mitochondria through a process called mitophagy. More recently, roles for other programmed mechanisms of cell death such as necroptosis and pyroptosis have been described, and inhibitors of these pathways have been shown to be cardioprotective. In this review, we discuss both mitochondrial and mitochondrial-independent pathways of the major modes of cell death, their role in IR injury and their potential to be targeted as part of a cardioprotective strategy. This article is part of a special Issue entitled 'Mitochondria as targets of acute cardioprotection' and emerged as part of the discussions of the European Union (EU)-CARDIOPROTECTION Cooperation in Science and Technology (COST) Action, CA16225.

Circular RNA circFOXO3 promotes prostate cancer progression through sponging miR-29a-3p.

Abstract: Circular RNA FOXO3 (CircFOXO3, also termed as Hsa_circ_0006404) is derived from exon 2 of forkhead box O3 (FOXO3) gene, and abnormal expression is shown in different diseases. However, whether circFOXO3 plays important roles in tumorigenesis and progression of prostate cancer (PCa) remains unclear. In this study, we found that circFOXO3 was up-regulated in both PCa tissues and serum samples. Moreover, circFOXO3 was positively correlated with the Gleason score in PCa samples. CircFOXO3 was observed to be up-regulated in Gleason score > 6 PCa samples compared with Gleason score = 6 PCa samples. Knock-down circFOXO3 could remarkably inhibit PCa cell cycle, proliferation and promote cell apoptosis in vitro. Furthermore, we demonstrated circFOXO3 could act as miR-29a-3p sponge to up-regulate SLC25A15 expression by bioinformatics analysis, dual-luciferase reporter assays and biotinylated RNA pull-down assays. SLC25A15 could reverse the tumour suppressing roles of knock-down circFOXO3 in PCa. Of note, we found that miR-29a-3p was down-regulated; however, SLC25A15 was overexpressed in PCa samples compared with normal tissues. In conclusion, circFOXO3 acts as a miR-29a-3p sponge to exhibit oncogenic activity that affects the cell cycle and cell apoptosis in PCa through transcriptional up-regulation of SLC25A15. Our analysis suggests circFOXO3 could act as promising prostate cancer biomarkers.

Scientific research progress of COVID-19/SARS-CoV-2 in the first five months.

Abstract: A cluster of pneumonia (COVID-19) cases have been found in Wuhan China in late December, 2019, and subsequently, a novel coronavirus with a positive stranded RNA was identified to be the aetiological virus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2), which has a phylogenetic similarity to severe acute respiratory syndrome coronavirus (SARS-CoV). SARS-CoV-2 transmits mainly through droplets and close contact and the elder or people with chronic diseases are high-risk population. People affected by SARS-CoV-2 can be asymptomatic, which brings about more difficulties to control the transmission. COVID-19 has become pandemic rapidly after onset, and so far the infected people have been above 2 000 000 and more than 130 000 died worldwide according to COVID-19 situation dashboard of World Health Organization (https://covid19.who.int). Here, we summarized the current known knowledge regarding epidemiological, pathogenesis, pathology, clinical features, comorbidities and treatment of COVID-19/ SARS-CoV-2 as reference for the prevention and control COVID-19.

METTL3/YTHDF2 m 6 A axis promotes tumorigenesis by degrading SETD7 and KLF4 mRNAs in bladder cancer

Abstract: N6-Methyladenosine (m6 A) modification, the most prevalent modification of eukaryotic messenger RNA (mRNA), is involved in the progression of various tumours. However, the specific role of m6 A in bladder cancer (BCa) is still poorly understood. In this study, we demonstrated the tumour-promoting function and specific regulatory mechanism of m6 A axis, consisting of the core 'writer' protein METTL3 and the major reader protein YTHDF2. Depletion of METTL3 impaired cancer proliferation and cancer metastasis in vitro and in vivo. Through transcriptome sequencing, m6 A methylated RNA immunoprecipitation (MeRIP) and RIP, we determined that the METTL3/YTHDF2 m6 A axis directly degraded the mRNAs of the tumour suppressors SETD7 and KLF4, contributing to the progression of BCa. In addition, overexpression of SETD7 and KLF4 revealed a phenotype consistent with that induced by depletion of the m6 A axis. Thus, our findings on the METTL3/YTHDF2/SETD7/KLF4 m6 A axis provide the insight into the underlying mechanism of carcinogenesis and highlight potential therapeutic targets for BCa.

New mechanism of nerve injury in Alzheimer's disease: β-amyloid-induced neuronal pyroptosis.

Abstract: The present study was designed to investigate the role of β-amyloid (Aβ1-42 ) in inducing neuronal pyroptosis and its mechanism. Mice cortical neurons (MCNs) were used in this study, LPS + Nigericin was used to induce pyroptosis in MCNs (positive control group), and Aβ1-42 was used to interfere with MCNs. In addition, propidium iodide (PI) staining was used to examine cell permeability, lactate dehydrogenase (LDH) release assay was employed to detect cytotoxicity, immunofluorescence (IF) staining was used to investigate the expression level of the key protein GSDMD, Western blot was performed to detect the expression levels of key proteins, and enzyme-linked immunosorbent assay (ELISA) was utilized to determine the expression levels of inflammatory factors in culture medium, including IL-1β, IL-18 and TNF-α. Small interfering RNA (siRNA) was used to silence the mRNA expression of caspase-1 and GSDMD, and Aβ1-42 was used to induce pyroptosis, followed by investigation of the role of caspase-1-mediated GSDMD cleavage in pyroptosis. In addition, necrosulfonamide (NSA), an inhibitor of GSDMD oligomerization, was used for pre-treatment, and Aβ1-42 was subsequently used to observe the pyroptosis in MCNs. Finally, AAV9-siRNA-caspase-1 was injected into the tail vein of APP/PS1 double transgenic mice (Alzheimer's disease mice) for caspase-1 mRNA inhibition, followed by observation of behavioural changes in mice and measurement of the expression of inflammatory factors and pyroptosis-related protein. As results, Aβ1-42 could induce pyroptosis in MCNs, increase cell permeability and enhance LDH release, which were similar to the LPS + Nigericin-induced pyroptosis. Meanwhile, the expression levels of cellular GSDMD and p30-GSDMD were up-regulated, the levels of NLRP3 inflammasome and GSDMD-cleaved protein caspase-1 were up-regulated, and the levels of inflammatory factors in the medium were also up-regulated. siRNA intervention in caspase-1 or GSDMD inhibited Aβ1-42 -induced pyroptosis, and NSA pre-treatment also caused the similar inhibitory effects. The behavioural ability of Alzheimer's disease (AD) mice was relieved after the injection of AAV9-siRNA-caspase-1, and the expression of pyroptosis-related protein in the cortex and hippocampus was down-regulated. In conclusion, Aβ1-42 could induce pyroptosis by GSDMD protein, and NLRP3-caspase-1 signalling was an important signal to mediate GSDMD cleavage, which plays an important role in Aβ1-42 -induced pyroptosis in neurons. Therefore, GSDMD is expected to be a novel therapeutic target for AD.

Mechanotransduction pathways in the regulation of cartilage chondrocyte homoeostasis.

Abstract: Mechanical stress plays a critical role in cartilage development and homoeostasis. Chondrocytes are surrounded by a narrow pericellular matrix (PCM), which absorbs dynamic and static forces and transmits them to the chondrocyte surface. Recent studies have demonstrated that molecular components, including perlecan, collagen and hyaluronan, provide distinct physical properties for the PCM and maintain the essential microenvironment of chondrocytes. These physical signals are sensed by receptors and molecules located in the cell membrane, such as Ca2+ channels, the primary cilium and integrins, and a series of downstream molecular pathways are involved in mechanotransduction in cartilage. All mechanoreceptors convert outside signals into chemical and biological signals, which then regulate transcription in chondrocytes in response to mechanical stresses. This review highlights recent progress and focuses on the function of the PCM and cell surface molecules in chondrocyte mechanotransduction. Emerging understanding of the cellular and molecular mechanisms that regulate mechanotransduction will provide new insights into osteoarthritis pathogenesis and precision strategies that could be used in its treatment.

Circular RNA in renal diseases

Abstract: Circular RNA (circRNA) is a newly described type of non-coding RNA. Active research is greatly enriching the current understanding of the expression and role of circRNA, and a large amount of evidence has implicated circRNA in the pathogenesis of certain renal diseases, such as renal cell carcinoma, acute kidney injury, diabetic nephropathy and lupus nephritis. Studies have found evidence that circRNAs regulate programmed cell death, invasion, and metastasis and serve as biomarkers in renal diseases. Recently, circRNAs were identified in exosomes secreted by the kidneys. Nevertheless, the function of circRNA in renal diseases remains ambiguous. Given that circRNAs are regulators of gene expression, they may be involved in the pathology of multiple renal diseases. Additionally, emerging evidence is showing that circulating circRNAs may serve as novel biomarkers for renal disease. In this review, we have summarized the identification, biogenesis, degradation, and functions of circRNA and have evaluated the roles of circRNA in renal diseases.

Endoplasmic reticulum stress‐induced exosomal miR‐27a‐3p promotes immune escape in breast cancer via regulating PD‐L1 expression in macrophages

Abstract: Immune escape of breast cancer cells contributes to breast cancer pathogenesis. Tumour microenvironment stresses that disrupt protein homeostasis can produce endoplasmic reticulum (ER) stress. The miRNA-mediated translational repression of mRNAs has been extensively studied in regulating immune escape and ER stress in human cancers. In this study, we identified a novel microRNA (miR)-27a-3p and investigated its mechanistic role in promoting immune evasion. The binding affinity between miR-27a-3p and MAGI2 was predicted using bioinformatic analysis and verified by dual-luciferase reporter assay. Ectopic expression and inhibition of miR-27a-3p in breast cancer cells were achieved by transduction with mimics and inhibitors. Besides, artificial modulation of MAGI2 and PTEN was done to explore their function in ER stress and immune escape of cancer cells. Of note, exosomes were derived from cancer cells and co-cultured with macrophages for mechanistic studies. The experimental data suggested that ER stress biomarkers including GRP78, PERK, ATF6, IRE1α and PD-L1 were overexpressed in breast cancer tissues relative to paracancerous tissues. Endoplasmic reticulum stress promoted exosome secretion and elevated exosomal miR-27a-3p expression. Elevation of miR-27a-3p and PD-L1 levels in macrophages was observed in response to exosomes-overexpressing miR-27a-3p in vivo and in vitro. miR-27a-3p could target and negatively regulate MAGI2, while MAGI2 down-regulated PD-L1 by up-regulating PTEN to inactivate PI3K/AKT signalling pathway. Less CD4+ , CD8+ T cells and IL-2, and T cells apoptosis were observed in response to co-culture of macrophages and CD3+ T cells. Conjointly, exosomal miR-27a-3p promotes immune evasion by up-regulating PD-L1 via MAGI2/PTEN/PI3K axis in breast cancer.

High expression of WTAP leads to poor prognosis of gastric cancer by influencing tumour-associated T lymphocyte infiltration.

Abstract: Background N6-methyladenosine (m6A) methylation, a well-known modification with new epigenetic functions, has been reported to participate in gastric cancer (GC) tumourigenesis, providing novel insights into the molecular pathogenesis of GC. However, the involvement of Wilms' tumour 1-associated protein (WTAP), a key component of m6A methylation, in GC progression is controversial. Here, we investigated the biological role and underlying mechanism of WTAP in GC. Methods We determined WTAP expression using tissue microarrays and The Cancer Genome Atlas (TCGA) data set, which was used to construct co-expression networks by weighted gene co-expression network analysis (WGCNA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed by Database for Annotation, Visualization and Integrated Discovery (DAVID). CIBERSORT was used to determine WTAP expression in 22 immune cell types. Results Wilms' tumour 1-associated protein was highly expressed in GC, which indicated a poor prognosis, and WTAP expression served as an independent predictor of GC survival. By WGCNA, GO, KEGG and core gene survival analyses, we found that high WTAP expression correlated with RNA methylation and that low expression correlated with a high T cell-related immune response. CIBERSORT was used to correlate low WTAP expression with T lymphocyte infiltration. Conclusion RNA methylation and lymphocyte infiltration are the main causes of high WTAP expression and poor prognosis, respectively.

Down-regulated lncRNA SBF2-AS1 in M2 macrophage-derived exosomes elevates miR-122-5p to restrict XIAP, thereby limiting pancreatic cancer development.

Abstract: Evidence has indicated that M2 macrophages promote the progression of cancers, but few focus on the ability of M2 macrophage-derived exosomes in pancreatic cancer (PC). This study aims to explore how M2 macrophages affect malignant phenotypes of PC through regulating long non-coding RNA SET-binding factor 2 antisense RNA 1 (lncRNA SBF2-AS1)/microRNA-122-5p (miR-122-5p)/X-linked inhibitor of apoptosis protein (XIAP) axis. THP-1 cells were transformed into M1 macrophages by lipopolysaccharide and interferon-γ treatment, and into M2 macrophages after interleukin-4 treatment. The PANC-1 PC cell line with the largest lncRNA SBF2-AS1 expression was selected, and M2 macrophage-derived exosomes were isolated and identified. A number of assays were applied for the examination of lncRNA SBF2-AS1 expression, PC cell biological functions and subcellular localization of lncRNA SBF2-AS1. XIAP expression was detected, along with the interaction among lncRNA SBF2-AS1, miR-122-5p and XIAP. M2 macrophage exosomal lncRNA SBF2-AS1 expression's effects on the tumorigenic ability of PANC-1 cells in nude mice were also investigated. M2 macrophage-derived exosomes promoted progression of PC cells. Overexpressed lncRNA SBF2-AS1 promoted progression of PC cells. LncRNA SBF2-AS1 was found to act as a competing endogenous RNA to repress miR-122-5p and up-regulate XIAP. Constrained lncRNA SBF2-AS1 in M2 macrophage-derived exosomes contributed to restraining tumorigenic ability of PC cells. Collectively, our study reveals that constrained lncRNA SBF2-AS1 in M2 macrophage-derived exosomes increases miR-122-5p expression to restrain XIAP expression, which further inhibits PC progression.

Mesenchymal stem cells-derived exosomes ameliorate intervertebral disc degeneration through inhibiting pyroptosis

Abstract: Mesenchymal stem cell (MSCs)-based therapies have shown a promised result for intervertebral disc degeneration (IVDD) treatment. However, its molecular mechanisms remain unclear. Exosomes involve cell-cell communication via transference of its contents among different cells, and the present potential effect on cell death regulation. This study aimed to investigate the role of MSCs-derived exosomes on IVDD formation. Here, we first found the NLRP3-mediated nucleus pulposus cell (NP cell) pyroptosis was activated in the IVDD mice model and lipopolysaccharide (LPS)-induced model. However, MSCs treatment could inhibit NP cell pyroptosis in vitro. We then isolated MSCs-derived exosomes by differential centrifugation and identified the characteristics. Secondly, we investigated the function of MSCs-derived exosomes on LPS-induced NP cell pyroptosis. Finally, we presented evidence that MSCs-derived exosomal miR-410 was a crucial regulator of pyroptosis. Results showed that MSCs-derived exosomes play an anti-pyroptosis role by suppressing the NLRP3 pathway. Moreover, it suggested that this effect was attributed to miR-410, which was derived from MSCs-exosomes and could directly bind to NLRP3mRNA. In conclusion, for the first time, we demonstrated that MSCs-exosome treatment may inhibit pyroptosis and could be a promising therapeutic strategy for IVDD.

Allopurinol reduces oxidative stress and activates Nrf2/p62 to attenuate diabetic cardiomyopathy in rats.

Abstract: Allopurinol (ALP) attenuates oxidative stress and diabetic cardiomyopathy (DCM), but the mechanism is unclear. Activation of nuclear factor erythroid 2-related factor 2 (Nrf2) following the disassociation with its repressor Keap1 under oxidative stress can maintain inner redox homeostasis and attenuate DCM with concomitant attenuation of autophagy. We postulated that ALP treatment may activate Nrf2 to mitigate autophagy over-activation and consequently attenuate DCM. Streptozotocin-induced type 1 diabetic rats were untreated or treated with ALP (100 mg/kg/d) for 4 weeks and terminated after heart function measurements by echocardiography and pressure-volume conductance system. Cardiomyocyte H9C2 cells infected with Nrf2 siRNA or not were incubated with high glucose (HG, 25 mmol/L) concomitantly with ALP treatment. Cell viability, lactate dehydrogenase, 15-F2t-Isoprostane and superoxide dismutase (SOD) were measured with colorimetric enzyme-linked immunosorbent assays. ROS, apoptosis, was assessed by dihydroethidium staining and TUNEL, respectively. The Western blot and qRT-PCR were used to assess protein and mRNA variations. Diabetic rats showed significant reductions in heart rate (HR), left ventricular eject fraction (LVEF), stroke work (SW) and cardiac output (CO), left ventricular end-systolic volume (LVVs) as compared to non-diabetic control and ALP improved or normalized HR, LVEF, SW, CO and LVVs in diabetic rats (all P < .05). Hearts of diabetic rats displayed excessive oxidative stress manifested as increased levels of 15-F2t-Isoprostane and superoxide anion production, increased apoptotic cell death and cardiomyocytes autophagy that were concomitant with reduced expressions of Nrf2, heme oxygenase-1 (HO-1) and Keap1. ALP reverted all the above-mentioned diabetes-induced biochemical changes except that it did not affect the levels of Keap1. In vitro, ALP increased Nrf2 and reduced the hyperglycaemia-induced increases of H9C2 cardiomyocyte hypertrophy, oxidative stress, apoptosis and autophagy, and enhanced cellular viability. Nrf2 gene silence cancelled these protective effects of ALP in H9C2 cells. Activation of Nrf2 subsequent to the suppression of Keap1 and the mitigation of autophagy over-activation may represent major mechanisms whereby ALP attenuates DCM.

Curcumin reinforces MSC-derived exosomes in attenuating osteoarthritis via modulating the miR-124/NF-kB and miR-143/ROCK1/TLR9 signalling pathways

Abstract: Curcumin treatment was reported to delay the progression of OA, but its underlying mechanism remains unclear. In this study, we aimed to investigate the molecular mechanism underlying the role of curcumin in OA treatment. Accordingly, by conducting MTT and flow cytometry assays, we found that the exosomes derived from curcumin-treated MSCs helped to maintain the viability while inhibiting the apoptosis of model OA cells. Additionally, quantitative real-time PCR and Western blot assays showed that the exosomes derived from curcumin-treated MSCs significantly restored the down-regulated miR-143 and miR-124 expression as well as up-regulated NF-kB and ROCK1 expression in OA cells. Mechanistically, curcumin treatment decreased the DNA methylation of miR-143 and miR-124 promoters. In addition, the 3' UTRs of NF-kB and ROCK1 were proven to contain the binding sites for miR-143 and miR-124, respectively. Therefore, the up-regulation of miR-143 and miR-124 in cellular and mouse OA models treated with exosomes remarkably restored the normal expression of NF-kB and ROCK1. Consequently, the progression of OA was attenuated by the exosomes. Our results clarified the molecular mechanism underlying the therapeutic role of MSC-derived exosomes in OA treatment.

Cardiac metabolism as a driver and therapeutic target of myocardial infarction.

Abstract: Reducing infarct size during a cardiac ischaemic-reperfusion episode is still of paramount importance, because the extension of myocardial necrosis is an important risk factor for developing heart failure. Cardiac ischaemia-reperfusion injury (IRI) is in principle a metabolic pathology as it is caused by abruptly halted metabolism during the ischaemic episode and exacerbated by sudden restart of specific metabolic pathways at reperfusion. It should therefore not come as a surprise that therapy directed at metabolic pathways can modulate IRI. Here, we summarize the current knowledge of important metabolic pathways as therapeutic targets to combat cardiac IRI. Activating metabolic pathways such as glycolysis (eg AMPK activators), glucose oxidation (activating pyruvate dehydrogenase complex), ketone oxidation (increasing ketone plasma levels), hexosamine biosynthesis pathway (O-GlcNAcylation; administration of glucosamine/glutamine) and deacetylation (activating sirtuins 1 or 3; administration of NAD+ -boosting compounds) all seem to hold promise to reduce acute IRI. In contrast, some metabolic pathways may offer protection through diminished activity. These pathways comprise the malate-aspartate shuttle (in need of novel specific reversible inhibitors), mitochondrial oxygen consumption, fatty acid oxidation (CD36 inhibitors, malonyl-CoA decarboxylase inhibitors) and mitochondrial succinate metabolism (malonate). Additionally, protecting the cristae structure of the mitochondria during IR, by maintaining the association of hexokinase II or creatine kinase with mitochondria, or inhibiting destabilization of FO F1 -ATPase dimers, prevents mitochondrial damage and thereby reduces cardiac IRI. Currently, the most promising and druggable metabolic therapy against cardiac IRI seems to be the singular or combined targeting of glycolysis, O-GlcNAcylation and metabolism of ketones, fatty acids and succinate.

Angiotensin II-induced redox-sensitive SGLT1 and 2 expression promotes high glucose-induced endothelial cell senescence

Abstract: High glucose (HG)-induced endothelial senescence and dysfunction contribute to the increased cardiovascular risk in diabetes. Empagliflozin, a selective sodium glucose co-transporter2 (SGLT2) inhibitor, reduced the risk of cardiovascular mortality in type 2 diabetic patients but the protective mechanism remains unclear. This study examines the role of SGLT2 in HG-induced endothelial senescence and dysfunction. Porcine coronary artery cultured endothelial cells (ECs) or segments were exposed to HG (25 mmol/L) before determination of senescence-associated beta-galactosidase activity, protein level by Western blot and immunofluorescence staining, mRNA by RT-PCR, nitric oxide (NO) by electron paramagnetic resonance, oxidative stress using dihydroethidium and glucose uptake using 2-NBD-glucose. HG increased ECs senescence markers and oxidative stress, down-regulated eNOS expression and NO formation, and induced the expression of VCAM-1, tissue factor, and the local angiotensin system, all these effects were prevented by empagliflozin. Empagliflozin and LX-4211 (dual SGLT1/2 inhibitor) reduced glucose uptake stimulated by HG and H2 O2 in ECs. HG increased SGLT1 and 2 protein levels in cultured ECs and native endothelium. Inhibition of the angiotensin system prevented HG-induced ECs senescence and SGLT1 and 2 expression. Thus, HG-induced ECs ageing is driven by the local angiotensin system via the redox-sensitive up-regulation of SGLT1 and 2, and, in turn, enhanced glucotoxicity.

Exosomes from human urine‐derived stem cells enhanced neurogenesis via miR‐26a/HDAC6 axis after ischaemic stroke

Abstract: Endogenous neurogenesis holds promise for brain repair and long-term functional recovery after ischaemic stroke. However, the effects of exosomes from human urine-derived stem cells (USC-Exos) in neurogenesis remain unclear. This study aimed to investigate whether USC-Exos enhanced neurogenesis and promoted functional recovery in brain ischaemia. By using an experimental stroke rat model, we found that intravenous injection of USC-Exos enhanced neurogenesis and alleviated neurological deficits in post-ischaemic stroke rats. We used neural stem cells (NSCs) subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) as an in vitro model of ischaemic stroke. The in vitro results suggested that USC-Exos promoted both proliferation and neuronal differentiation of NSCs after OGD/R. Notably, a further mechanism study revealed that the pro-neurogenesis effects of USC-Exos may be partially attributed to histone deacetylase 6 (HDAC6) inhibition via the transfer of exosomal microRNA-26a (miR-26a). Taken together, this study indicates that USC-Exos can be used as a novel promising strategy for brain ischaemia, which highlights the application of USC-Exos.

Effects of doxorubicin-induced cardiotoxicity on cardiac mitochondrial dynamics and mitochondrial function: Insights for future interventions.

Abstract: Anthracyclines is an effective chemotherapeutic treatment used for many types of cancer. However, high cumulative dosage of anthracyclines leads to cardiac toxicity and heart failure. Dysregulation of mitochondrial dynamics and function are major pathways driving this toxicity. Several pharmacological and non-pharmacological interventions aiming to attenuate cardiac toxicity by targeting mitochondrial dynamics and function have shown beneficial effects in cell and animal models. However, in clinical practice, there is currently no standard therapy for the prevention of anthracycline-induced cardiotoxicity. This review summarizes current reports on the impact of anthracyclines on cardiac mitochondrial dynamics and mitochondrial function and potential interventions targeting these pathways. The roles of mitochondrial dynamics and mitochondrial function in the development of anthracycline-induced cardiotoxicity should provide insights in devising novel strategies to attenuate the cardiac toxicity induced by anthracyclines.

Circular RNA hsa_circRNA_002178 silencing retards breast cancer progression via microRNA-328-3p-mediated inhibition of COL1A1.

Abstract: Circular RNAs (circRNAs) are a group of non-coding RNAs implicated in the pathogenesis of cancer progression, which exert their functions via regulation of microRNAs (miRNAs) and genes. The present study uses gain- and loss-of-function approaches to evaluate the functions of hsa_circRNA_002178 in angiogenesis along with energy metabolism and underlying downstream signals. The expression pattern of hsa_circRNA_002178 in clinical breast cancer tissues and its association with prognosis were characterized at first. Next, the energy metabolism and angiogenesis as well as cell viability were evaluated when the expression of hsa_circRNA_002178 in breast cancer cells was knocked down by siRNA. The interaction between hsa_circRNA_002178 and its downstream miR-328-3p was identified, followed by the analysis of their functions in regulation of breast cancer cellular behaviours. The target gene of miR-328-3p was predicted and verified, followed by identifying its role in the breast cancer progression. Higher expression of hsa_circRNA_002178 shared an association with worse prognosis in breast cancer. The inhibition of hsa_circRNA_002178 resulted in reductions in cell viability, energy metabolism and tube formation ability. Hsa_circRNA_002178 could competitively bind to miR-328-3p and down-regulated its expression. Restoration of miR-328-3p eliminated the tumour-promoting effects of hsa_circRNA_002178. COL1A1, as a target of miR-328-3p, could be up-regulated by overexpression of hsa_circRNA_002178. In vivo experiments further confirmed the inhibition of tumour growth and inflammation by silencing hsa_circRNA_002178 or up-regulating miR-328-3p. Taken together, hsa_circRNA_002178 is highlighted as a promising target for breast cancer due to the anti-tumour effects achieved by silencing hsa_circRNA_002178.

RNA demethylase ALKBH5 promotes ovarian carcinogenesis in a simulated tumour microenvironment through stimulating NF-κB pathway.

Abstract: Methylation is the main form of RNA modification. N6-methyladenine (m6A) regulates the splicing and translation of mRNA. Alk B homologue 5 (ALKBH5) participates in the biological regulation of various cancers. However, its role in ovarian carcinogenesis has not been unveiled. In the present study, ALKBH5 showed higher expression in ovarian cancer tissue than in normal ovarian tissue, but lower expression in ovarian cancer cell lines than in normal ovarian cell lines. Interestingly, Toll-like receptor (TLR4), a molecular functioning in tumour microenvironment (TME), demonstrated the same expression trend. To investigate the effect of abnormal TME on ovarian carcinogenesis, we established an in vitro model in which macrophages and ovarian cancer cells were co-cultured. In the ovarian cancer cells co-cultured with M2 macrophages, the expression of ALKBH5 and TLR4 increased. We also verified that TLR4 up-regulated ALKBH5 expression via activating NF-κB pathway. Depending on transcriptome sequencing, m6A-Seq and m6A MeRIP, we found that NANOG served as a target in ALKBH5-mediated m6A modification. NANOG expression increased after mRNA demethylation, consequently enhancing the aggressiveness of ovarian cancer cells. In conclusion, highly expressed TLR4 activated NF-κB pathway, up-regulated ALKBH5 expression and increased m6A level and NANOG expression, all contributing to ovarian carcinogenesis. Our study revealed the role of m6A in ovarian carcinogenesis, providing a clue for inventing new target therapy.

Diabetes aggravates myocardial ischaemia reperfusion injury via activating Nox2-related programmed cell death in an AMPK-dependent manner.

Abstract: Cardiovascular diseases such as myocardial ischaemia have a high fatality rate in patients with diabetes. This study was designed to expose the crosstalk between oxidative stress and AMPK, a vital molecule that controls biological energy metabolism, in myocardial ischaemia reperfusion injury (I/RI) in diabetic rats. Diabetes was stimulated in rats using streptozotocin injection. Rats were separated on random into control, control + I/R, Diabetes, Diabetes + I/R, Diabetes + I/R + N-acetylcysteine and Diabetes + I/R + Vas2870 groups. Myocardial infarct size was determined, and the predominant Nox family isoforms were analysed. In vitro, the H9C2 cells were administered excess glucose and exposed to hypoxia/reoxygenation to mimic diabetes and I/R. The AMPK siRNA or AICAR was used to inhibit or activate AMPK expression in H9C2 cells, respectively. Then, myocardial oxidative stress and programmed cell death were measured. Diabetes or high glucose levels were found to aggravate myocardial I/RI or hypoxia/reoxygenation in H9C2 cells, as demonstrated by an increase in myocardial infarct size or lactate dehydrogenase levels, oxidative stress generation and induction of programmed cell death. In diabetic rat hearts, cardiac Nox1, Nox2 and Nox4 were all heightened. The suppression of Nox2 expression using Vas2870 or Nox2-siRNA treatment in vivo or in vitro, respectively, protected diabetic rats from myocardial I/RI. AMPK gene knockout increased Nox2 protein expression while AMPK agonist decreased Nox2 expression. Therefore, diabetes aggravates myocardial I/RI by generating of Nox2-associated oxidative stress in an AMPK-dependent manner, which led to the induction of programmed cell death such as apoptosis, pyroptosis and ferroptosis.

LncRNA H19 ameliorates myocardial infarction-induced myocardial injury and maladaptive cardiac remodelling by regulating KDM3A.

Abstract: Myocardial infarction (MI) remains the leading cause of morbidity and mortality worldwide, and novel therapeutic targets still need to be investigated to alleviate myocardial injury and the ensuing maladaptive cardiac remodelling. Accumulating studies have indicated that lncRNA H19 might exert a crucial regulatory effect on cardiovascular disease. In this study, we aimed to explore the biological function and molecular mechanism of H19 in MI. To investigate the biological functions of H19, miRNA-22-3p and KDM3A, gain- and loss-of-function experiments were performed. In addition, bioinformatics analysis, dual-luciferase reporter assays, RNA immunoprecipitation (RIP) assays, RNA pull-down assays, quantitative RT-PCR and Western blot analyses as well as rescue experiments were conducted to reveal an underlying competitive endogenous RNA (ceRNA) mechanism. We found that H19 was significantly down-regulated after MI. Functionally, enforced H19 expression dramatically reduced infarct size, improved cardiac performance and alleviated cardiac fibrosis by mitigating myocardial apoptosis and decreasing inflammation. However, H19 knockdown resulted in the opposite effects. Bioinformatics analysis and dual-luciferase assays revealed that, mechanistically, miR-22-3p was a direct target of H19, which was also confirmed by RIP and RNA pull-down assays in primary cardiomyocytes. In addition, bioinformatics analysis and dual-luciferase reporter assays also demonstrated that miRNA-22-3p directly targeted the KDM3A gene. Moreover, subsequent rescue experiments further verified that H19 regulated the expression of KDM3A to ameliorate MI-induced myocardial injury in a miR-22-3p-dependent manner. The present study revealed the critical role of the lncRNAH19/miR-22-3p/KDM3A pathway in MI. These findings suggest that H19 may act as a potential biomarker and therapeutic target for MI.

Long non‐coding RNA (lncRNA) H19 induces hepatic steatosis through activating MLXIPL and mTORC1 networks in hepatocytes

Abstract: Liver plays an essential role in regulating lipid metabolism, and chronically disturbed hepatic metabolism may cause obesity and metabolic syndrome, which may lead to non-alcoholic fatty liver disease (NAFLD). Increasing evidence indicates long non-coding RNAs (lncRNAs) play an important role in energy metabolism. Here, we investigated the role of lncRNA H19 in hepatic lipid metabolism and its potential association with NAFLD. We found that H19 was up-regulated in oleic acid-induced steatosis and during the development of high-fat diet (HFD)-induced NAFLD. Exogenous overexpression of H19 in hepatocytes induced lipid accumulation and up-regulated the expression of numerous genes involved in lipid synthesis, storage and breakdown, while silencing endogenous H19 led to a decreased lipid accumulation in hepatocytes. Mechanistically, H19 was shown to promote hepatic steatosis by up-regulating lipogenic transcription factor MLXIPL. Silencing Mlxipl diminished H19-induced lipid accumulation in hepatocytes. Furthermore, H19-induced lipid accumulation was effectively inhibited by PI3K/mTOR inhibitor PF-04691502. Accordingly, H19 overexpression in hepatocytes up-regulated most components of the mTORC1 signalling axis, which were inhibited by silencing endogenous H19. In vivo hepatocyte implantation studies further confirm that H19 promoted hepatic steatosis by up-regulating both mTORC1 signalling axis and MLXIPL transcriptional network. Collectively, these findings strongly suggest that H19 may play an important role in regulating hepatic lipid metabolism and may serve as a potential therapeutic target for NAFLD.

Crosstalk between cancer-associated fibroblasts and immune cells in cancer.

Abstract: Multiple studies have shown that cancer-associated fibroblasts (CAFs) play an important role in tumour progression, including carcinogenesis, invasion, metastasis and the chemoresistance of cancer cells. Immune cells, including macrophages, natural killer cells, dendritic cells and T cells, play a dual role in the tumour microenvironment. Although increasing research has focused on studying interactions between distinct cells in the tumour microenvironment, the complex relationships between CAFs and immune cells remain unclear and need further study. Here, we summarize our current understanding of crosstalk between CAFs and immune cells, which may help clarify their diagnostic and therapeutic value in tumour progression.

Activating Nrf2 signalling alleviates osteoarthritis development by inhibiting inflammasome activation

Abstract: Osteoarthritis (OA), which is characterized by proliferation of subchondral bone and the degeneration of articular cartilage, is the most prevalent human arthritis. Nod-like receptor pyrin domain 3 (NLRP3) inflammasome is a hot spot in recent year and has been reported to be associated with OA synovial inflammation. However, there are few studies on NLRP3 inflammasome in chondrocyte. Licochalcone A (Lico A), a compound extracted from Glycyrrhiza species, has various biological effects such as anti-inflammation, anti-apoptotic, anti-cancer and anti-oxidation. In this study, we investigated the protective effect of Lico A on chondrocytes stimulated by lipopolysaccharide (LPS) and surgically induced OA models. In vitro, Lico A could reduce the expression of NLRP3, apoptosis-associated speck-like protein (ASC), Gasdermin D (GSDMD), caspase-1, interleukin-1beta (IL-1β) and IL-18, which indicated that Lico A attenuates LPS-induced chondrocytes pyroptosis. In addition, Lico A ameliorates the degradation of extracellular matrix (ECM) by enhancing the expression of aggrecan and collagen-II. Meanwhile, we found that Lico A inhibits NLRP3 inflammasome via nuclear factor erythroid-2-related factor 2 (Nrf2)/haeme oxygenase-1(HO-1)/nuclear factor kappa-B (NF-κB) axis. And the Nrf2 small interfering RNA (siRNA) could reverse the anti-pyroptosis effects of Lico A in mouse OA chondrocytes. In vivo, Lico A mitigates progression OA in a mouse model and reduces OA Research Society International (OARSI) scores. Thus, Lico A may have therapeutic potential in OA.

Pancreatic cancer cell-derived exosomal microRNA-27a promotes angiogenesis of human microvascular endothelial cells in pancreatic cancer via BTG2.

Abstract: Pancreatic cancer (PC) remains a primary cause of cancer-related deaths worldwide. Existing literature has highlighted the oncogenic role of microRNA-27a (miR-27a) in multiple cancers. Hence, the current study aimed to clarify the potential therapeutic role of PC cell-derived exosomal miR-27a in human microvascular endothelial cell (HMVEC) angiogenesis in PC. Initially, differentially expressed genes (DEGs) and miRs related to PC were identified by microarray analysis. Microarray analysis provided data predicting the interaction between miR-27a and BTG2 in PC, which was further verified by the elevation or depletion of miR-27a. Next, the expression of miR-27a and BTG2 in the PC tissues was quantified. HMVECs were exposed to exosomes derived from PC cell line PANC-1 to investigate the effects associated with PC cell-derived exosomes carrying miR-27a on HMVEC proliferation, invasion and angiogenesis. Finally, the effect of miR-27a on tumorigenesis and microvessel density (MVD) was analysed after xenograft tumour inoculation in nude mice. Our results revealed that miR-27a was highly expressed, while BTG2 was poorly expressed in both PC tissues and cell lines. miR-27a targeted BTG2. Moreover, miR-27a silencing inhibited PC cell proliferation and invasion, and promoted apoptosis through the elevation of BTG2. The in vitro assays revealed that PC cell-derived exosomes carrying miR-27a stimulated HMVEC proliferation, invasion and angiogenesis, while this effect was reversed in the HMVECs cultured with medium containing GW4869-treated PANC-1 cells. Furthermore, in vivo experiment revealed that miR-27a knockdown suppressed tumorigenesis and MVD. Taken together, cell-derived exosomes carrying miR-27a promotes HMVEC angiogenesis via BTG2 in PC.

CircRNA WHSC1 targets the miR-646/NPM1 pathway to promote the development of endometrial cancer.

Abstract: Circular RNAs (circRNAs) play important roles in human cancer progression. Their high stability and tissue specificity make circRNAs important molecular targets for clinical diagnosis, treatment and prognosis. However, the functions and molecular mechanisms of circRNA WHSC1 in endometrial cancer are unknown. CircWHSC1 expression in normal endometrial and endometrial cancer tissues was detected using PCR. Overexpression or knockdown of circWHSC1 in endometrial cancer cell lines HEC-1B or Ishikawa, respectively, cell function experiments were used to detect the impact of circWHSC1 on endometrial cancer cells. A nude mouse xenograft model was used to detect changes in tumorigenesis of HEC-1B cells after circWHSC1 overexpression. Bioinformatics and dual luciferase reporter gene technology were used to predict and validate the sponging ability of circWHSC1 on microRNAs. Gene expression changes were detected by using Western blotting. CircWHSC1 expression was increased in endometrial cancer tissues. CircWHSC1 overexpression promoted the proliferation, migration and invasion of endometrial cancer cells and decreased apoptosis. CircWHSC1 knockdown had the opposite effect. CircWHSC1 overexpressed nude mice showed increased tumorigenicity. Bioinformatics predicted that circWHSC1 binds to miR-646, which was confirmed using luciferase reporter gene assays. High expression of miR-646 could reverse the effect of circWHSC1 on endometrial cancer cells. Western blotting showed increased or decreased levels of nucleophosmin 1 (NPM1), an miR-646 downstream target, after circWHSC1 overexpression or knockdown, respectively. CircWHSC1 promotes endometrial cancer development through sponging miR-646 and targeting NPM1.