Mitofusin2 Induces Cell Autophagy of Pancreatic Cancer through Inhibiting the PI3K/Akt/mTOR Signaling Pathway

Puerarin relives inflammation, bone destruction and facilitates osteogenic differentiation in periodontitis by enhancing mitochondrial autophagy via activating mitochondrial Mitofusin 2

PURPOSE

Puerarin (Pue) has recently been reported to have therapeutic effects on periodontitis (PD). However, there is insufficient evidence, and the mechanism involved has not yet been revealed. This work delved to explore the exact therapeutic effects and molecular mechanism of Pue in treating PD.

METHODS

PD mouse (C57BL/6 N mouse) model constructed by Porphyromonas gingivalis-lipopolysaccharide (Pg-LPS) induction was treated with Pue. Therapeutic efficacy of Pue for PD was examined by a series of experiments. PD cell model was induced by treating human periodontal ligament cells with Pg-LPS. Therapeutic effects of Pue on PD cell model, along with the potential molecular mechanism, were explored by logical experiments. Rescue experiments based on in vitro and in vivo studies were implemented to validate the molecular mechanism of Pue in treating PD.

RESULTS

In PD mice, Pue treatment relieved inflammation and bone destruction, facilitated osteogenic differentiation and autophagy in periapical tissues. In PD cell model, Pue treatment facilitated osteogenic differentiation and mitochondrial autophagy; suppressed inflammation and mitochondrial reactive oxygen species; maintained mitochondrial membrane potential and mitochondrial kinetic homeostasis; and activated mitochondrial Mitofusin 2 (Mfn2). However, these influences of Pue on PD cell model were eliminated by CsA (mitochondrial autophagy inhibitor). The enhanced mitochondrial autophagy induced by Pue was reversed by Mfn2 silencing. Through in vivo data, Mfn2 knockdown counteracted the therapeutic effects of Pue on PD mice.

CONCLUSION

Pue exerted therapeutic effects on PD, possibly by enhancing mitochondrial autophagy via activating mitochondrial Mfn2. This might be a cure for PD.

The Balance of MFN2 and OPA1 in Mitochondrial Dynamics, Cellular Homeostasis, and Disease

Mitochondrial dynamics, governed by fusion and fission, are crucial for maintaining cellular homeostasis, energy production, and stress adaptation. MFN2 and OPA1, key regulators of mitochondrial fusion, play essential roles beyond their structural functions, influencing bioenergetics, intracellular signaling, and quality control mechanisms such as mitophagy. Disruptions in these processes, often caused by MFN2 or OPA1 mutations, are linked to neurodegenerative diseases like Charcot-Marie-Tooth disease type 2A (CMT2A) and autosomal dominant optic atrophy (ADOA). This review explores the molecular mechanisms underlying mitochondrial fusion, the impact of MFN2 and OPA1 dysfunction on oxidative phosphorylation and autophagy, and their role in disease progression. Additionally, we discuss the divergent cellular responses to MFN2 and OPA1 mutations, particularly in terms of proliferation, senescence, and metabolic signaling. Finally, we highlight emerging therapeutic strategies to restore mitochondrial integrity, including mTOR modulation and autophagy-targeted approaches, with potential implications for neurodegenerative disorders.

Metabolic plasticity in pancreatic cancer: The mitochondrial connection

BACKGROUND

Cellular metabolism plays a pivotal role in the development and progression of pancreatic ductal adenocarcinoma (PDAC), with dysregulated metabolic pathways contributing to tumorigenesis and therapeutic resistance. Distinct metabolic heterogeneity in pancreatic cancer significantly impacts patient prognosis, as variations in metabolic profiles influence tumor behavior and treatment responses.

SCOPE OF THE REVIEW

This review explores the intricate interplay between mitochondrial dynamics, mitophagy, and cellular metabolism in PDAC. We discuss the significance of mitophagy dysregulation in PDAC pathogenesis, emphasizing its influence on treatment responses and prognosis. Furthermore, we analyze the impact of mitochondrial dynamics alterations, including fission and fusion processes, on PDAC progression and tumorigenesis.

MAJOR CONCLUSION

Targeting mitochondrial metabolism holds promise for advancing PDAC therapeutics. Ongoing clinical trials underscore the therapeutic potential of modulating key regulators of mitochondrial dynamics and mitophagy. Despite inherent challenges, these approaches offer diverse strategies to enhance treatment efficacy and improve patient outcomes.

Role of Sphingosine-1-Phosphate Signaling Pathway in Pancreatic Diseases

Sphingosine-1-phosphate (S1P) is a sphingolipid metabolic product produced via the phosphorylation of sphingosine by sphingosine kinases (SPHKs), serving as a powerful modulator of various cellular processes through its interaction with S1P receptors (S1PRs). Currently, this incompletely understood mechanism in pancreatic diseases including pancreatitis and pancreatic cancer, largely limits therapeutic options for these disorders. Recent evidence indicates that S1P significantly contributes to pancreatic diseases by modulating inflammation, promoting pyroptosis in pancreatic acinar cells, regulating the activation of pancreatic stellate cells, and affecting organelle functions in pancreatic cancer cells. Nevertheless, no review has encapsulated these advancements. Thus, this review compiles information about the involvement of S1P signaling in exocrine pancreatic disorders, including acute pancreatitis, chronic pancreatitis, and pancreatic cancer, as well as prospective treatment strategies to target S1P signaling for these conditions. The insights presented here possess the potential to offer valuable guidance for the implementation of therapies targeting S1P signaling in various pancreatic diseases.

SPDEF drives pancreatic adenocarcinoma progression via transcriptional upregulation of S100A16 and activation of the PI3K/AKT signaling pathway

Pancreatic adenocarcinoma (PAAD) is a notably aggressive malignancy with limited treatment options and an unfavorable prognosis for patients. We aimed to investigate molecular mechanisms by which Sam's pointed domain-containing ETS transcription factor (SPDEF) exerts effects on PAAD progression. We analyzed differentially expressed genes (DEGs) and their integration with ETS family members using the The Cancer Genome Atlas (TCGA) database, hence identifying SPDEF as a core gene in PAAD. Kaplan-Meier survival analysis confirmed SPDEF's prognostic potential. In vitro experiments validated the association with cell proliferation and apoptosis, affecting pancreatic cancer cell dynamics. We detected increased SPDEF expression in PAAD tumor samples. Our in vitro studies revealed that SPDEF regulates mRNA and protein expression levels, and significantly affects cell proliferation. Moreover, SPDEF was associated with reduced apoptosis and enhanced cell migration and invasion. In-depth analysis of SPDEF-targeted genes revealed four crucial genes for advanced prognostic model, among which S100A16 was significantly correlated with SPDEF. Mechanistic analysis showed that SPDEF enhances the transcription of S100A16, which in turn enhances PAAD cell migration, proliferation, and invasion by activating the PI3K/AKT signaling pathway. Our study revealed the critical role of SPDEF in promoting PAAD by upregulating S100A16 transcription and stimulating the PI3K/AKT signaling pathway. This knowledge deepened our understanding of pancreatic cancer's molecular progression and unveiled potential therapeutic strategies targeting SPDEF-driven pathways.

Mechanism and Therapeutic Prospect of miRNAs in Neurodegenerative Diseases

MicroRNAs (miRNAs) are the smallest class of noncoding RNAs, which widely exist in animals and plants. They can inhibit translation or overexpression by combining with mRNA and participate in posttranscriptional regulation of genes, resulting in reduced expression of target proteins, affecting the development, growth, aging, metabolism, and other physiological and pathological processes of animals and plants. It is a powerful negative regulator of gene expression. It mediates the information exchange between different cellular pathways in cellular homeostasis and stress response and regulates the differentiation, plasticity, and neurotransmission of neurons. In neurodegenerative diseases, in addition to the complex interactions between genetic susceptibility and environmental factors, miRNAs can serve as a promising diagnostic tool for diseases. They can also increase or reduce neuronal damage by regulating the body's signaling pathways, immune system, stem cells, gut microbiota, etc. They can not only affect the occurrence of diseases and exacerbate disease progression but also promote neuronal repair and reduce apoptosis, to prevent and slow down the development of diseases. This article reviews the research progress of miRNAs on the mechanism and treatment of neurodegenerative diseases in the nervous system. This trial is registered with NCT01819545, NCT02129452, NCT04120493, NCT04840823, NCT02253732, NCT02045056, NCT03388242, NCT01992029, NCT04961450, NCT03088839, NCT04137926, NCT02283073, NCT04509271, NCT02859428, and NCT05243017.

The mitochondrial fusion-associated protein MFN2 can be used as a novel prognostic molecule for clear cell renal cell carcinoma

BACKGROUND

Mitofusin 2 (MFN2) plays an important role in many tumors, but how its role in renal clear cell carcinoma needs further research.

METHODS

In this study, we analyzed the expression of MFN2 in renal clear cell carcinoma tissues and normal kidney tissues through the Cancer Genome Atlas (TCGA) database and our clinical samples.Enrichment analysis was performed to determine MFN2-related pathways and biological functions. The correlation of MFN2 expression with immune cells was analyzed.The correlation of the expression of methylation and the methylation sites of MFN2 were analyzed by UALCAN and TCGA databases. Univariate / multivariate COX risk regression and Kaplan-Meier methods were used to determine the prognostic value of MFN2.Nomograms were drawn to predict overall survival (OS) at 1,3, and 5 years. We investigated the role of MFN2 in renal cancer cells using CCK 8, clone formation, wound healing assay, and methylase qPCR experiments.

RESULTS

MFN2 is poorly expressed in renal clear cell carcinoma compared to normal kidney tissue,and is significantly negatively associated with TNM stage, histological grade and pathological stage.MFN2 was directly associated with OS after multivariate Cox regression analysis.MFN2 shows a hypomethylation state and shows a positive correlation with multiple methylation sites.Signaling pathways through functional enrichment to B-cell receptors and oxidative stress-induced senescence.Moreover, the low expression of MFN2 was positively correlated with the degree of immune cell infiltration in a variety of immune cells.In vitro experiments showed that overexpression of MFN2 significantly inhibited the proliferation and migration of renal clear cells and promoted methylation.

CONCLUSIONS

In conclusion, MFN2 can be used as a novel prognostic marker for renal clear cell carcinoma and requires further investigation of its role in tumor development.

Mitofusin 2 mutation drives cell proliferation in Charcot-Marie-Tooth 2A fibroblasts

Dominant mutations in ubiquitously expressed mitofusin 2 gene (MFN2) cause Charcot-Marie-Tooth type 2A (CMT2A; OMIM 609260), an inherited sensory-motor neuropathy that affects peripheral nerve axons. Mitofusin 2 protein has been found to take part in mitochondrial fusion, mitochondria-endoplasmic reticulum tethering, mitochondrial trafficking along axons, mitochondrial quality control and various types of cancer, in which MFN2 has been indicated as a tumor suppressor gene. Discordant data on the mitochondrial altered phenotypes in patient-derived fibroblasts harboring MFN2 mutations and in animal models have been reported. We addressed some of these issues by focusing on mitochondria behavior during autophagy and mitophagy in fibroblasts derived from a CMT2AMFN2 patient with an MFN2650G > T/C217F mutation in the GTPase domain. This study investigated mitochondrial dynamics, respiratory capacity and autophagy/mitophagy, to tackle the multifaceted MFN2 contribution to CMT2A pathogenesis. We found that MFN2 mutated fibroblasts showed impairment of mitochondrial morphology, bioenergetics capacity, and impairment of the early stages of autophagy, but not mitophagy. Unexpectedly, transcriptomic analysis of mutated fibroblasts highlighted marked differentially expressed pathways related to cell population proliferation and extracellular matrix organization. We consistently found the activation of mTORC2/AKT signaling and accelerated proliferation in the CMT2AMFN2 fibroblasts. In conclusion, our evidence indicates that MFN2 mutation can positively drive cell proliferation in CMT2AMFN2 fibroblasts.

Facile and Green Fabrication of Highly Competent Surface-Modified Chlorogenic Acid Silver Nanoparticles: Characterization and Antioxidant and Cancer Chemopreventive Potential

The eco-friendly, cost-effective, and green fabrication of nanoparticles is considered a promising area of nanotechnology. Here, we report on the green synthesis and characterization of bovine serum albumin (BSA)-decorated chlorogenic acid silver nanoparticles (AgNPs-CGA-BSA) and the studies undertaken to verify their plausible antioxidant and antineoplastic effects. High-resolution transmission electron microscopy (HR-TEM), dynamic light scattering, X-ray diffraction, and Fourier transform infrared analyses depict an average mean particle size of ∼96 nm, spherical morphology, and nanocrystalline structure of AgNPs-CGA-BSA. DPPH scavenging and inhibition of lipid peroxidation signify the noticeable in vitro antioxidant potential of the nanoparticles. The in vitro experimental results demonstrate that AgNPs-CGA-BSA shows significant cytotoxicity to Dalton's lymphoma ascites (DLA) cells and generates an enhanced intracellular reactive oxygen species and oxidized glutathione (GSSG) and reduced glutathione (GSH) in DLA cells. Furthermore, mechanism investigation divulges the pivotal role of the downregulated expression of superoxide dismutase (SOD) and catalase (CAT), and these ultimately lead to apoptotic chromatin condensation in AgNPs-CGA-BSA-treated DLA cells. In addition, in vivo experiments reveal an excellent decrease in tumor cell count, an increase in serum GSH and CAT, SOD, and glutathione peroxidase activities, and a decrease in the malondialdehyde (MDA) level in DLA-bearing mice after AgNPs-CGA-BSA treatment. These findings suggest that the newly synthesized biogenic green silver nanoparticles have remarkable in vitro antioxidant and antineoplastic efficacy that triggers cytotoxicity, oxidative stress, and chromatin condensation in DLA cells and in vivo anticancer efficacy that enhances the host antioxidant status, and these might open a new path in T-cell lymphoma therapy.

Mfn2-mediated mitochondrial fusion promotes autophagy and suppresses ovarian cancer progression by reducing ROS through AMPK/mTOR/ERK signaling

Mitochondrial dynamics are balanced fission and fusion events that regulate mitochondrial morphology, and alteration in these events results in mitochondrial dysfunction and contributes to many diseases, including tumorigenesis. Ovarian cancer (OC) cells exhibit fragmented mitochondria, but the mechanism by which mitochondrial dynamics regulators contribute to OC is considerably less clear. Here, we elucidated the potential role of Mfn2-mediated mitochondrial fusion in OC and present evidence that genetic or pharmacological activation of Mfn2 leads to mitochondrial fusion and reduces ROS generation, which correlates with reduced cell proliferation, invasion, migration, and EMT in OC cells. Also, increased mitochondrial fusion promotes the F-actin remodeling, reduces lamellipodia formation, and thus reduces EMT. Increased expression of Mfn2 triggers AMPK, promotes autophagy, reduces ROS, and suppresses OC progression by downregulating  the p-mTOR (2481 and 2448) and p-ERK axis. OC patients with higher Mfn2 expression have better survival than those with lower Mfn2 levels. Our findings demonstrate that restoration of Mfn2-mediated mitochondrial fusion suppressed OC progression and suggest that this process could be a potential strategy in OC treatment.

Prognostic impact of mitofusin 2 expression in colon cancer

BACKGROUND

Mitofusin 2 (MFN2) is involved in several biological processes, including cancer. MFN2 is downregulated in some types of cancer and inhibits cancer cell proliferation, migration, and invasion. However, the relationship between MFN2 and colon cancer remains unknown.

METHODS

In this study, MFN2 expression was investigated using The Cancer Genome Atlas (TCGA) and the Human Protein Atlas (HPA), and the associations between prognostic factors and survival outcomes were assessed via univariate and multivariate analyses. Functional enrichment analyses based on Kyoto Encyclopedia of Genes and Genomes (KEGG) resource and Gene Set Enrichment Analysis (GSEA) were carried out.

RESULTS

MFN2 was downregulated in colon cancer tissues compared with paracancerous colon tissues (P<0.001), and low MFN2 expression was associated with an advanced tumor stage (stage IV vs. stage I, P=0.03; stage I-III vs. stage IV, P=0.003). MFN2 immunohistochemistry (IHC) staining was medium to high in colon normal tissues, but MFN2 IHC staining was faint or not identified in colorectal cancer (CRC) tumor tissues. MFN2 expression was either low or non-existent in colon cancer distinct cell clusters, according to differential gene analysis. Univariate analysis revealed that MFN2 expression in colon cancer patients was significantly associated with the stage [odds ratio (OR) =0.29 for stage IV vs. stage I, P=0.001], T-stage (OR =0.20 for T4 vs. T1, P=0.033), and distant metastasis (OR =0.31 for M1 vs. M0, P=0.000). Furthermore, Kaplan-Meier survival analysis revealed that patients with colon cancer and high MFN2 expression have a better prognosis than those with low MFN2 expression (P=0.002). MFN2 (hazard ratio =0.95, 95% confidence interval: 0.92-0.99, P=0.007) was an independent predictor of colon cancer according to univariate and multivariate Cox models. Finally, GSEA results showed that the KEGG GALACTOSE METABOLISM, APOPTOSIS, and VEGF SIGNALING pathways were activated in the high MFN2 mRNA expression group, whereas the KEGG RIBOSOME pathway was inhibited in the low MFN2 expression group.

CONCLUSIONS

Our research revealed MFN2 to be a promising predictive biomarker and therapeutic target for colon cancer.

Mitofusin-2 in cancer: Friend or foe?

Cancer is a category of disorders characterized by excessive cell proliferation with the ability to infiltrate or disseminate to other organs of the body. Mitochondrial dysfunction, as one of the most prominent hallmarks of cancer cells, has been related to the onset and development of various cancers. Mitofusin 2 (MFN2) is a major mediator of mitochondrial fusion, endoplasmic reticulum (ER)-mitochondria interaction, mitophagy and axonal transport of mitochondria. Available data have shown that MFN2, which its alterations have been associated with mitochondrial dysfunction, could affect cancer initiation and progression. In fact, it showed that MFN2 may have a double-edged sword effect on cancer fate. Precisely, it demonstrated that MFN2, as a tumor suppressor, induces cancer cell apoptosis and inhibits cell proliferation via Ca²⁺ and Bax-mediated apoptosis and increases P21 and p27 levels, respectively. It also could suppress cell survival via inhibiting PI3K/Akt, Ras-ERK1/2-cyclin D1 and mTORC2/Akt signaling pathways. On the other hand, MFN2, as an oncogene, could increase cancer invasion via snail-mediated epithelial-mesenchymal transition (EMT) and in vivo tumorigenesis. While remarkable progress has been achieved in recent decades, further exploration is required to elucidate whether MFN2 could be a friend or it's an enemy. This study aimed to highlight the different functions of MFN2 in various cancers.

Comprehensive analysis of MFN2 as a prognostic biomarker associated with immune cell infiltration in renal clear cell carcinoma

BACKGROUND

Treatment of advanced kidney renal clear cell carcinoma (KIRC) remains challenging in clinic. The functional role and prognostic significance of MFN2 in KIRC are still unclear.

METHODS

In this study, we first performed a bioinformatic analysis to determine the expression level and prognostic value of MFN2 in KIRC using The Cancer Genome Atlas (TCGA) dataset, and then validated the MFN2 mRNA expression in our cohort of clinical tissue samples and cell lines of KIRC via RT-qPCR. Cox regression model was used to identify the independent prognostic factors. A nomogram was constructed to predict the prognosis of KIRC patients. Gene set enrichment analysis (GSEA) was performed to predict the involved functional pathways of MFN2 co-expressed genes. The association between MFN2 expression level and immune cell infiltration was assessed using the TIMER and the TIDISB databases. In addition, cell proliferation and migration abilities of two KIRC cell lines with MFN2 overexpression were evaluated by MTS and wound healing assays, respectively.

RESULTS

Downregulation of MFN2 was observed in KIRC tissues and cell lines compared to the normal controls. Kaplan-Meier curve analysis indicated an inferior survival outcomes in KIRC patients with lower MFN2 expression, uncovering the tumor-suppressive role of MFN2 in KIRC. Cox regression results showed that higher MFN2 expression was one of the independent protective factors in KIRC. Besides, function predictive analysis revealed that MFN2 co-expressed genes were enriched in the biological processes of energy metabolism and autophagy. Moreover, MFN2 expression was observed to be significantly associated with immune cell infiltration and a variety of markers of tumor infiltrating immune cells (TIICs) including multiple immune checkpoints in KIRC tissues. Finally, MFN2 overexpression significantly inhibited cell proliferation and migration abilities of two KIRC cell lines examined.

CONCLUSION

Generally, our data suggested that MFN2 may serve as a potential prognostic biomarker and therapeutic target in KIRC.

Divergent Roles of Mitochondria Dynamics in Pancreatic Ductal Adenocarcinoma

Simple Summary

Pancreatic ductal adenocarcinoma is one of the most lethal neoplasia due to the lack of early diagnostic markers and effective therapies. The study of metabolic alterations of PDAC is of crucial importance since it would open the way to the discovery of new potential therapies. Mitochondria represent key organelles that regulate energy metabolism, and they remodel their structure by undergoing modifications by fusing with other mitochondria or dividing to generate smaller ones. The alterations of mitochondria arrangement may influence the metabolism of PDAC cells, thus supporting the proliferative needs of cancer. Shedding light on this topic regarding cancer and, more specifically, PDAC may help identify new potential strategies that hit cancer cells at their “core,” i.e., mitochondria.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors; it is often diagnosed at an advanced stage and is hardly treatable. These issues are strictly linked to the absence of early diagnostic markers and the low efficacy of treatment approaches. Recently, the study of the metabolic alterations in cancer cells has opened the way to important findings that can be exploited to generate new potential therapies. Within this scenario, mitochondria represent important organelles within which many essential functions are necessary for cell survival, including some key reactions involved in energy metabolism. These organelles remodel their shape by dividing or fusing themselves in response to cellular needs or stimuli. Interestingly, many authors have shown that mitochondrial dynamic equilibrium is altered in many different tumor types. However, up to now, it is not clear whether PDAC cells preferentially take advantage of fusion or fission processes since some studies reported a wide range of different results. This review described the role of both mitochondria arrangement processes, i.e., fusion and fission events, in PDAC, showing that a preference for mitochondria fragmentation could sustain tumor needs. In addition, we also highlight the importance of considering the metabolic arrangement and mitochondria assessment of cancer stem cells, which represent the most aggressive tumor cell type that has been shown to have distinctive metabolic features to that of differentiated tumor cells.

Pimavanserin: A Novel Autophagy Modulator for Pancreatic Cancer Treatment

Pancreatic tumors exhibit high basal autophagy compared to that of other cancers. Several studies including those from our laboratory reported that enhanced autophagy leads to apoptosis in cancer cells. In this study, we evaluated the autophagy and apoptosis inducing effects of Pimavanserin tartrate (PVT). Autophagic effects of PVT were determined by Acridine Orange assay and Transmission Electron Microscopy analysis. Clinical significance of ULK1 in normal and pancreatic cancer patients was evaluated by R2 and GEPIA cancer genomic databases. Modulation of proteins in autophagy signaling was assessed by Western blotting and Immunofluorescence. Apoptotic effects of PVT was evaluated by Annexin-V/APC assay. Subcutaneous xenograft pancreatic tumor model was used to evaluate the autophagy-mediated apoptotic effects of PVT in vivo. Autophagy was induced upon PVT treatment in pancreatic ducal adenocarcinoma (PDAC) cells. Pancreatic cancer patients exhibit reduced levels of autophagy initiator gene, ULK1, which correlated with reduced patient survival. Interestingly, PVT induced the expression of autophagy markers ULK1, FIP200, Atg101, Beclin-1, Atg5, LC3A/B, and cleavage of caspase-3, an indicator of apoptosis in several PDAC cells. ULK1 agonist LYN-1604 enhanced the autophagic and apoptotic effects of PVT. On the other hand, autophagy inhibitors chloroquine and bafilomycin blocked the autophagic and apoptotic effects of PVT in PDAC cells. Notably, chloroquine abrogated the growth suppressive effects of PVT by 25% in BxPC3 tumor xenografts in nude mice. Collectively, our results indicate that PVT mediated pancreatic tumor growth suppression was associated with induction of autophagy mediated apoptosis.

Mitochondrial dynamics regulators: implications for therapeutic intervention in cancer

Regardless of the recent advances in therapeutic developments, cancer is still among the primary causes of death globally, indicating the need for alternative therapeutic strategies. Mitochondria, a dynamic organelle, continuously undergo the fusion and fission processes to meet cell requirements. The balanced fission and fusion processes, referred to as mitochondrial dynamics, coordinate mitochondrial shape, size, number, energy metabolism, cell cycle, mitophagy, and apoptosis. An imbalance between these opposing events alters mitochondWangrial dynamics, affects the overall mitochondrial shape, and deregulates mitochondrial function. Emerging evidence indicates that alteration of mitochondrial dynamics contributes to various aspects of tumorigenesis and cancer progression. Therefore, targeting the mitochondrial dynamics regulator could be a potential therapeutic approach for cancer treatment. This review will address the role of imbalanced mitochondrial dynamics in mitochondrial dysfunction during cancer progression. We will outline the clinical significance of mitochondrial dynamics regulators in various cancer types with recent updates in cancer stemness and chemoresistance and its therapeutic potential and clinical utility as a predictive biomarker.

Autophagy inhibition facilitates wound closure partially dependent on the YAP/IL-33 signaling in a mouse model of skin wound healing

Autophagy is a self-phagocytic and highly evolutionarily conserved intracellular lysosomal catabolic system, which plays a vital role in a variety of trauma models, including skin wound healing (SWH). However, the roles and potential mechanisms of autophagy in SWH are still controversial. We firstly investigated the role of autophagy in SWH-induced wound closure rate, inflammatory response, and histopathology, utilizing an inhibitor of autophagy 3-methyladenine (3-MA) and its agonist rapamycin (RAP). As expected, we found 3-MA treatment remarkably increased the wound closure rate, combated inflammation response, and mitigated histopathological changes, while RAP delivery aggravated SWH-induced pathological damage. To further exploit the underlying mechanism of autophagy regulating inflammation, the specific inhibitors of yes-associated protein (YAP), Verteporfin, and Anti-IL-33 were applied. Herein, treating with 3-MA markedly suppressed the expression of tumor necrosis factor-α (TNF-α), IL-1β, and IL-6, promoted that of IL-10, IL-33, and ST2, while RAP administration reverted SWH-induced the up-regulation of these inflammatory cytokines mentioned above. Importantly, Verteporfin administration not only down-regulated the expression levels of YAP, TNF-α, and IL-6 but also up-regulated that of IL-33 and IL-10. Unexpectedly, 3-MA or RAP retreatment did not have any impact on the changes in IL-33 among these inflammatory indicators. Furthermore, elevated expression of IL-33 promoted wound closure and alleviated the pathological damage, whereas, its antagonist Anti-IL-33 treatment overtly reversed the above-mentioned effects of IL-33. Moreover, 3-MA in combination with anti-IL-33 treatment reversed the role of 3-MA alone in mitigated pathological changes, but they failed to revert the effect of anti-IL-33 alone on worsening pathological damage. In sum, emerging data support the novel contribution of the YAP/IL-33 pathway in autophagy inhibition against SWH-induced pathological damage, and highlight that the autophagy/YAP/IL-33 signal axis is expected to become a new therapeutic target for SWH.

MicroRNA-17-5p Promotes Cardiac Hypertrophy by Targeting Mfn2 to Inhibit Autophagy

Pathological cardiac hypertrophy is the leading cause of heart failure, and miRNAs have been recognized as key factors in cardiac hypertrophy. This study aimed to elucidate whether miR-17-5p affects cardiac hypertrophy by targeting the mitochondrial fusion protein mitofusin 2 (Mfn2)-mediated phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway and regulating autophagy. miR-17-5p expression was shown to be upregulated both in vivo and in vitro. In addition, a miR-17-5p inhibitor significantly reversed AngII-induced cell hypertrophy in neonatal rat left ventricle myocytes (NRVMs). In contrast to miR-17-5p expression, Mfn2 expression was inhibited in rat hearts at 4 weeks after transverse aortic constriction (TAC) and in an Ang II-induced cell hypertrophy model. We examined miR-17-5p targeting of Mfn2 by dual luciferase reporter and Western blot assays. In addition, we also verified the relationship between Mfn2 and the PI3K/AKT/mTOR pathway. Mfn2 overexpression attenuated miR-17-5p-induced cell hypertrophy, and in rat myocardial tissue, miR-17-5p induced autophagy inhibition. In summary, the results of the present study demonstrated that miR-17-5p inhibits Mfn2 expression, activates the PI3K/AKT/mTOR pathway and suppresses autophagy to promote cardiac hypertrophy.

Oridonin induces autophagy-mediated cell death in pancreatic cancer by activating the c-Jun N-terminal kinase pathway and inhibiting phosphoinositide 3-kinase signaling

Background

Oridonin is a diterpenoid isolated from Rabdosia rubescens that has potent anticancer activity. This study set out to investigate the antitumor effects of oridonin in pancreatic carcinoma (PC) and their underlying mechanisms.

Methods

To investigate the antitumor effects of oridonin, we developed an orthotopic C57BL/6 mouse model of PC. After successful establishment of the model, the mice were given a daily intraperitoneal injection of phosphate-buffered saline containing 0.1% dimethyl sulfoxide or oridonin for 2 weeks. In vitro experiments including MTT assay and flow cytometry were performed to examine cell viability and apoptosis. Panc-1 and Panc02 cells were transfected with a green fluorescent protein (GFP)-LC3 plasmid. After the cells had been treated with or without 20 μM oridonin and 10 μM 3-MA, the formation of GFP-LC3 puncta was detected by fluorescence microscopy. The levels of the autophagy-related proteins Beclin-1, LC3, and p62 were measured by western blotting.

Results

Oridonin inhibited the proliferation of PC cells and induced their apoptosis in vitro and in vivo. Treatment with oridonin also led to an increase in the quantity of LC3B II protein and upregulation of the p62 and Beclin-1 levels in PC cells. The effects of oridonin on PC cell proliferation, apoptosis, and autophagy were mediated via the simultaneous inhibition of the phosphoinositide 3-kinase pathway and activation of the c-Jun N-terminal kinase pathway.

Conclusions

Our study is the first to confirm the antitumor and autophagy-activating effects of oridonin on PC cells. In light of these results, oridonin may be a promising therapeutic agent for PC.

Oxygen sensing, mitochondrial biology and experimental therapeutics for pulmonary hypertension and cancer

The homeostatic oxygen sensing system (HOSS) optimizes systemic oxygen delivery. Specialized tissues utilize a conserved mitochondrial sensor, often involving NDUFS2 in complex I of the mitochondrial electron transport chain, as a site of pO₂-responsive production of reactive oxygen species (ROS). These ROS are converted to a diffusible signaling molecule, hydrogen peroxide (H₂O₂), by superoxide dismutase (SOD2). H₂O₂ exits the mitochondria and regulates ion channels and enzymes, altering plasma membrane potential, intracellular Ca²⁺ and Ca²⁺-sensitization and controlling acute, adaptive, responses to hypoxia that involve changes in ventilation, vascular tone and neurotransmitter release. Subversion of this O₂-sensing pathway creates a pseudohypoxic state that promotes disease progression in pulmonary arterial hypertension (PAH) and cancer. Pseudohypoxia is a state in which biochemical changes, normally associated with hypoxia, occur despite normal pO₂. Epigenetic silencing of SOD2 by DNA methylation alters H₂O₂ production, activating hypoxia-inducible factor 1α, thereby disrupting mitochondrial metabolism and dynamics, accelerating cell proliferation and inhibiting apoptosis. Other epigenetic mechanisms, including dysregulation of microRNAs (miR), increase pyruvate dehydrogenase kinase and pyruvate kinase muscle isoform 2 expression in both diseases, favoring uncoupled aerobic glycolysis. This Warburg metabolic shift also accelerates cell proliferation and impairs apoptosis. Disordered mitochondrial dynamics, usually increased mitotic fission and impaired fusion, promotes disease progression in PAH and cancer. Epigenetic upregulation of dynamin-related protein 1 (Drp1) and its binding partners, MiD49 and MiD51, contributes to the pathogenesis of PAH and cancer. Finally, dysregulation of intramitochondrial Ca²⁺, resulting from impaired mitochondrial calcium uniporter complex (MCUC) function, links abnormal mitochondrial metabolism and dynamics. MiR-mediated decreases in MCUC function reduce intramitochondrial Ca²⁺, promoting Warburg metabolism, whilst increasing cytosolic Ca²⁺, promoting fission. Epigenetically disordered mitochondrial O₂-sensing, metabolism, dynamics, and Ca²⁺ homeostasis offer new therapeutic targets for PAH and cancer. Promoting glucose oxidation, restoring the fission/fusion balance, and restoring mitochondrial calcium regulation are promising experimental therapeutic strategies.

Mitofusin-2 is a novel anti-angiogenic factor in pancreatic cancer

Background

Aberrant expression of mitofusin-2 (MFN2) has been found to be associated with vascular endothelial growth factor A (VEGFA)-mediated angiogenesis in human umbilical vein endothelial cells (HUVECs). This study aimed to investigate the expression of MFN2 in pancreatic cancer (PC) and the role of MFN2 in vascular endothelial cell growth and angiogenesis.

Methods

Protein and mRNA expression of MFN2 and VEGFA were measured. The CCK-8 assay, tube formation assay, flow cytometry, and transmission electron microscopy were used to examine the effects of MFN2 overexpression on HUVEC growth, angiogenesis, and apoptosis. Western blot and immunocytochemical staining were conducted to measure alterations in cell cycle and apoptosis regulators and vascular endothelial growth factor receptor 2 (VEGFR2), angiopoietin-1 gene (ANGPT1), and tissue inhibitor of metalloproteinase 1 (TIMP1) expression in HUVECs.

Results

The results showed that MFN2 levels were significantly decreased in tumor tissues. Contrasting results were observed for VEGFA mRNA levels. MFN2 overexpression inhibited cell growth while promoting the formation of apoptotic bodies in HUVECs. Additionally, MFN2 overexpression enhanced the protein expression of p21 and p27 while attenuating the expression of proliferating cell nuclear antigen, VEGFA, VEGFR2, ANGPT1, and TIPM1 in HUVECs.

Conclusions

In conclusion, MFN2 expression negatively correlates with VEGFA expression in PC and inhibits endothelial cell growth and angiogenesis.

Perspectives on Organelle Interaction, Protein Dysregulation, and Cancer Disease

In recent decades, compelling evidence has emerged showing that organelles are not static structures but rather form a highly dynamic cellular network and exchange information through membrane contact sites. Although high-throughput techniques facilitate identification of novel contact sites (e.g., organelle-organelle and organelle-vesicle interactions), little is known about their impact on cellular physiology. Moreover, even less is known about how the dysregulation of these structures impacts on cellular function and therefore, disease. Particularly, cancer cells display altered signaling pathways involving several cell organelles; however, the relevance of interorganelle communication in oncogenesis and/or cancer progression remains largely unknown. This review will focus on organelle contacts relevant to cancer pathogenesis. We will highlight specific proteins and protein families residing in these organelle-interfaces that are known to be involved in cancer-related processes. First, we will review the relevance of endoplasmic reticulum (ER)-mitochondria interactions. This section will focus on mitochondria-associated membranes (MAMs) and particularly the tethering proteins at the ER-mitochondria interphase, as well as their role in cancer disease progression. Subsequently, the role of Ca²⁺ at the ER-mitochondria interphase in cancer disease progression will be discussed. Members of the Bcl-2 protein family, key regulators of cell death, also modulate Ca²⁺ transport pathways at the ER-mitochondria interphase. Furthermore, we will review the role of ER-mitochondria communication in the regulation of proteostasis, focusing on the ER stress sensor PERK (PRKR-like ER kinase), which exerts dual roles in cancer. Second, we will review the relevance of ER and mitochondria interactions with other organelles. This section will focus on peroxisome and lysosome organelle interactions and their impact on cancer disease progression. In this context, the peroxisome biogenesis factor (PEX) gene family has been linked to cancer. Moreover, the autophagy-lysosome system is emerging as a driving force in the progression of numerous human cancers. Thus, we will summarize our current understanding of the role of each of these organelles and their communication, highlighting how alterations in organelle interfaces participate in cancer development and progression. A better understanding of specific organelle communication sites and their relevant proteins may help to identify potential pharmacological targets for novel therapies in cancer control.

The Role of Mitochondria in the Chemoresistance of Pancreatic Cancer Cells

The first-line chemotherapies for patients with unresectable pancreatic cancer (PC) are 5-fluorouracil (5-FU) and gemcitabine therapy. However, due to chemoresistance the prognosis of patients with PC has not been significantly improved. Mitochondria are essential organelles in eukaryotes that evolved from aerobic bacteria. In recent years, many studies have shown that mitochondria play important roles in tumorigenesis and may act as chemotherapeutic targets in PC. In addition, according to recent studies, mitochondria may play important roles in the chemoresistance of PC by affecting apoptosis, metabolism, mtDNA metabolism, and mitochondrial dynamics. Interfering with some of these factors in mitochondria may improve the sensitivity of PC cells to chemotherapeutic agents, such as gemcitabine, making mitochondria promising targets for overcoming chemoresistance in PC.

Effect of photobiomodulation on mitochondrial dynamics in peripheral nervous system in streptozotocin-induced type 1 diabetes in rats

There is no effective treatment to halt peripheral nervous system damage in diabetic peripheral neuropathy. Mitochondria have been at the center of discussions as important factors in the development of neuropathy in diabetes. Photobiomodulation has been gaining clinical acceptance as it shows beneficial effects on a variety of nervous system disorders. In this study, the effects of photobiomodulation (904 nm, 45 mW, 6.23 J/cm², 0.13 cm², 60 ns pulsed time) on mitochondrial dynamics were evaluated in an adult male rat experimental model of streptozotocin-induced type 1 diabetes. Results presented here indicate that photobiomodulation could have an important role in preventing or reversing mitochondrial dynamics dysfunction in the course of peripheral nervous system damage in diabetic peripheral neuropathy. Photobiomodulation showed its effects on modulating the protein expression of mitofusin 2 and dynamin-related protein 1 in the sciatic nerve and in the dorsal root ganglia neurons of streptozotocin-induced type 1 diabetes in rats.

Identification of an Autophagy-Related Pair Signature for Predicting Prognoses and Immune Activity in Pancreatic Adenocarcinoma

BACKGROUND

Pancreatic adenocarcinoma (PAAD) spreads quickly and has a poor prognosis. Autophagy research on PAAD could reveal new biomarkers and targets for diagnosis and treatment.

METHODS

Autophagy-related genes were translated into autophagy-related gene pairs, and univariate Cox regression was performed to obtain overall survival (OS)-related IRGPs (P<0.001). LASSO Cox regression analyses were performed to construct an autophagy-related gene pair (ARGP) model for predicting OS. The Cancer Genome Atlas (TCGA)-PAAD cohort was set as the training group for model construction. The model predictive value was validated in multiple external datasets. Receiver operating characteristic (ROC) curves were used to evaluate model performance. Tumor microenvironments and immune infiltration were compared between low- and high-risk groups with ESTIMATE and CIBERSORT. Differentially expressed genes (DEGs) between the groups were further analyzed by Gene Ontology biological process (GO-BP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses and used to identify potential small-molecule compounds in L1000FWD.

RESULTS

Risk scores were calculated as follows: ATG4B|CHMP4C×(-0.31) + CHMP2B|MAP1LC3B×(0.30) + CHMP6|RIPK2 ×(-0.33) + LRSAM1|TRIM5×(-0.26) + MAP1LC3A|PAFAH1B2×(-0.15) + MAP1LC3A|TRIM21×(-0.08) + MET|MFN2×(0.38) + MET|MTDH×(0.47) + RASIP1|TRIM5×(-0.23) + RB1CC1|TPCN1×(0.22). OS was significantly shorter in the high-risk group than the low-risk group in each PAAD cohort. The ESTIMATE analysis showed no difference in stromal scores but a significant difference in immune scores (p=0.0045) and ESTIMATE scores (p=0.014) between the groups. CIBERSORT analysis showed higher naive B cell, Treg cell, CD8 T cell, and plasma cell levels in the low-risk group and higher M1 and M2 macrophage levels in the high-risk group. In addition, the results showed that naive B cells (r=-0.32, p<0.001), Treg cells (r=-0.31, p<0.001), CD8 T cells (r=-0.24, p=0.0092), and plasma cells (r=-0.2, p<0.026) were statistically correlated with the ARGP risk score. The top 3 enriched GO-BPs were signal release, regulation of transsynaptic signaling, and modulation of chemical synaptic transmission, and the top 3 enriched KEGG pathways were the insulin secretion, dopaminergic synapse, and NF-kappa B signaling pathways. Several potential small-molecule compounds targeting ARGs were also identified.

CONCLUSION

Our results demonstrate that the ARGP-based model may be a promising prognostic indicator for identifying drug targets in patients with PAAD.

Periplocin inhibits the growth of pancreatic cancer by inducing apoptosis via AMPK-mTOR signaling

BACKGROUND

Periplocin is a monomeric compound that exhibits anti-tumor activities. It is extracted from Cortex Periplocae.

OBJECTIVE

This study aimed at determining the effect of periplocin treatment on the apoptosis and proliferation of human pancreatic cancer cells, and to elucidate on its mechanisms of action.

METHODS

PANC1 and cfpac1 cells were treated with periplocin. Cell proliferation was detected by RTCA, Ki67 immunofluorescence, and a clonogenic assay. The transwell assay was used to examine cell migration and invasion functions. The expression of apoptosis-associated proteins was detected by flow cytometry and western blotting. Total RNA was extracted from the treated and untreated group of PANC1 cells for RNA-seq detection and analysis. Differentially expressed genes were screened for GO biological process and KEGG pathway analysis. Finally, CFPAC1 cells were subcutaneously inoculated into BALB / c nude mice to assess tumor growth.

RESULTS

Periplocin inhibited the proliferation of PANC1 and CFPAC1 cells and induced their apoptosis by activating the AMPK/mTOR pathway and inhibiting p70 S6K. It also attenuated the cell migration, invasion, and inhibited the growth of cfpac1 xenografts in nude mice.

CONCLUSIONS

Periplocin inhibits human pancreatic cancer cell proliferation and induces their apoptosis by activating the AMPK / mTOR pathway.

"The Loss of Golden Touch": Mitochondria-Organelle Interactions, Metabolism, and Cancer

Mitochondria represent the energy hub of cells and their function is under the constant influence of their tethering with other subcellular organelles. Mitochondria interact with the endoplasmic reticulum, lysosomes, cytoskeleton, peroxisomes, and nucleus in several ways, ranging from signal transduction, vesicle transport, and membrane contact sites, to regulate energy metabolism, biosynthetic processes, apoptosis, and cell turnover. Tumorigenesis is often associated with mitochondrial dysfunction, which could likely be the result of an altered interaction with different cell organelles or structures. The purpose of the present review is to provide an updated overview of the links between inter-organellar communications and interactions and metabolism in cancer cells, with a focus on mitochondria. The very recent publication of several reviews on these aspects testifies the great interest in the area. Here, we aim at (1) summarizing recent evidence supporting that the metabolic rewiring and adaptation observed in tumors deeply affect organelle dynamics and cellular functions and vice versa; (2) discussing insights on the underlying mechanisms, when available; and (3) critically presenting the gaps in the field that need to be filled, for a comprehensive understanding of tumor cells’ biology. Chemo-resistance and druggable vulnerabilities of cancer cells related to the aspects mentioned above is also outlined.

Mitochondrial scenario: roles of mitochondrial dynamics in acute myocardial ischemia/reperfusion injury

The main therapeutic strategy currently used for acute myocardial infarction (AMI) is to open occluded coronary arteries, a process defined as blood reperfusion. However, blood reperfusion will increase cardiac mortality, tissue damage and cardiac dysfunction in patients with AMI, which is mechanically defined as "ischemia/reperfusion (I/R) injury". It is currently believed that mitochondrial dynamics plays a key role in myocardial I/R, especially excessive mitochondrial fission, which is the main cause of cardiac dysfunction. Therefore, in the process of I/R injury, effective drug intervention and correct treatment strategies can be used to regulate mitochondrial dynamic balance to combat ischemia-reperfusion injury, which can play a huge role in improving the prognosis of patients. This review summarized the effects of mitochondrial fission and mitochondrial fusion balance on myocardial and mitochondrial functional changes during myocardial I/R injury. Finally, combined with the previous injury mechanisms, this review also briefly described some drug intervention that may be beneficial to clinical practice to improve the postoperative quality of life of patients with AMI.

Downregulation of miR-33 Has Protective Effect Against Aβ₂₅₋₃₅-Induced Injury in SH-SH-SY5Y Cells

Background

Alzheimer disease (AD) is a significant health issue for the elderly, and there are at present no clinically effective anti-AD agents. Prevention of Aβ-induced neurotoxicity is proposed as a possible modality for treatment of AD. miR-33 has been proven to promote Aβ secretion and impair Aβ clearance in neural cells. The present study assessed whether miR-33 is involved in AD pathology.

Material/Methods

miR-33 level was detected by qRT-PCR. The Akt/mTOR pathway was analyzed by Western blot analysis. Neuron inflammation and oxidative stress were measured using commercial detection kits. Flow cytometry and Western blot assay were conducted to assess cell apoptosis, and Western blot assay was used to assess synaptic protein levels.

Results

miR-33 expression level was markedly upregulated in SH-SY5Y cells treated with Aβ_25–35. miR-33 knockdown suppressed inflammation, oxidative stress, and cell apoptosis. In addition, miR-33 knockdown improved synaptic plasticity, and the protective effect of miR-33 knockdown was discovered through suppressing activation of the Akt/mTOR signaling pathway.

Conclusions

Taken together, these findings suggest that miR-33 knockdown protects against Aβ_25–35-induced inflammation, oxidative stress, apoptosis, and synaptic damage by suppressing activation of the Akt/mTOR pathway.

Mitofusin2, a rising star in acute-on-chronic liver failure, triggers macroautophagy via the mTOR signalling pathway

Acute-on-chronic liver failure (ACLF) is a life-threatening syndrome with poor prognosis. Several studies have begun to prove that mitochondria play a crucial role in liver failure. Mitofusin2 (Mfn2) plays a key role in maintaining the integrity of mitochondrial morphology and function. However, the role and underlying mechanisms of Mfn2 on cell autophagy of ACLF remain unclear. Our aim was to explore the effect of Mfn2 on several biological functions involving cell autophagy in ACLF. In this study, we constructed an ACLF animal model and a hepatocyte autophagy model, using adenovirus and lentivirus to deliver Mfn2 to liver cells, in order to assess the effect of Mfn2 on autophagy and apoptosis in ACLF. Furthermore, we explored the biological mechanism of Mfn2-induced autophagy of ACLF using Western blotting, RT-PCR and electron microscopy. We found that Mfn2 significantly attenuated ACLF, characterized by ameliorated gross appearance and microscopic histopathology of liver, and reduced serum AST, ALT, and TBIL levels. Mfn2 improved the expressions of LC3-II, Atg5 and Bcl-2 and down-regulated the expression of P62 and Bax in ACLF. Like rapamycin, Mfn2 also significantly inhibited the expressions of p-PI3K, p-Akt and p-mTOR in ACLF. In conclusion, our findings suggest that Mfn2 influences multiple biological functions of ACLF via the PI3K/Akt/mTOR signalling pathway. This study will provide a reliable theoretical basis for the application of Mfn2 as an effective target for ACLF treatment, reversing or delaying the process of ACLF.

CircUBAP2-mediated competing endogenous RNA network modulates tumorigenesis in pancreatic adenocarcinoma

We investigated the role of the competing endogenous RNA (ceRNA) network in the development and progression of pancreatic adenocarcinoma (PAAD). We analyzed the expression profiles of PAAD and normal pancreatic tissues from multiple GEO databases and identified 457 differentially expressed circular RNAs (DEcircRNAs), 19 microRNAs (DEmiRNAs) and 1993 mRNAs (DEmRNAs). We constructed a ceRNA network consisting of 4 DEcircRNAs, 3 DEmiRNAs and 149 DEmRNAs that regulates the NF-kappa B, PI3K-Akt, and Wnt signaling pathways. We then identified and validated five hub genes, CXCR4, HIF1A, ZEB1, SDC1 and TWIST1, which are overexpressed in PAAD tissues. The expression of CXCR4, HIF1A, ZEB1, and SDC1 in PAAD was regulated by circ-UBAP2 and hsa-miR-494. The expression of CXCR4 and ZEB1 correlated with the levels of M2 macrophages, T-regulatory cells (Tregs) and exhausted T cells in the PAAD tissues. The expression of CXCR4 and ZEB1 positively correlated with the expression of CTLA-4 and PD-1. This suggests that CXCR4 and ZEB1 proteins inhibit antigen presentation and promote immune escape mechanisms in PAAD cells. In summary, our data suggest that the circUBAP2-mediated ceRNA network modulates PAAD by regulating the infiltration and function of immune cells.

Mfn2 inhibits proliferation and cell-cycle in Hela cells via Ras-NF-κB signal pathway

BACKGROUND

Mitofusin 2 (Mfn2) is outer membrane protein, as the inhibitor of Ras protein. This study aimed to investigate the effect of Mfn2 on cell proliferation, and cell-cycle in Hela cervical carcinoma cell lines.

METHODS

After treated with Adv-mfn2 or Adv-control for 48 h and 60 h, the RNA and protein of Mfn2 in Hela cells were detected by qRT-PCR and western blot. The immunofluorescence assay was performed to observe the expression and sub-location of Mfn2 in Hela cells. The flow cytometry was performed to detect the cell cycle of Hela cells, while western blots were performed to observe the Ras-NF-κB signal pathway. Then, the xenografted cervix carcinoma mouse model was used to confirm the effect of Mfn2 in Hela cells in vivo and the expression of Ras-NF-κB signaling pathway in vivo.

RESULTS

In immunofluorescence detection, Mfn2 was located in cytoplasmic, not in the nucleus. In addition, Mfn2 inhibited cell proliferation of Hela cells through reducing PCNA protein expression. Mfn2 induced arrest in G0/G1 phase of the cell cycle in Hela cells. Meanwhile, Mfn2 reduced Cyclin D1 protein expression. Moreover, Mfn2 decreased the Ras signal pathway proteins such as Myc, NF-κB p65, STAT3 in a dose-dependent manner. Then, the in vivo experiment also confirmed that Mfn2 could inhibit the tumor growth, and depress the Cyclin D1, Ras, Myc, NF-κB p65, Erk1/2 and mTOR protein expression.

CONCLUSIONS

Mfn2 could significantly inhibit cell proliferation in Hela cells. It might be acted as an potential anti-cancer target through inducing cell cycle arrest in human cervical carcinoma cells.

Vildagliptin inhibits high free fatty acid (FFA)-induced NLRP3 inflammasome activation in endothelial cells

Elevated free fatty acids (FFAs) are a risk factor for type 2 diabetes. Endothelial dysfunction induced by high levels of FFAs is one of the mechanisms related to the progression of diabetes. In clinical diabetes care, DPP-4 inhibitors have been shown to be effective in reducing glucose levels. In this study, we investigated the molecular mechanism of the clinically available DPP-4 inhibitor vildagliptin in the protection of FFA-induced endothelial dysfunction. Treatment of endothelial cells with vildagliptin inhibits FFA-induced cellular LDH release and generation of ROS. Vildagliptin also reverses FFA-induced reduced levels of GSH and elevated expression of the FFA-associated NAPHD oxidase protein NOX-4. Moreover, vildagliptin ameliorates the reduction in mitochondrial potential triggered by FFAs. Mechanistically, we show that vildagliptin suppresses FFA-induced expression of proteins of the NLRP3 inflammasome complex, including NLRP3, ASC, p20 and HMGB-1, and mitigates FFA-induced inactivation of the AMPK pathway. Consequently, vildagliptin inhibits production of two cytokines that are favored by NLRP3 inflammasome machinery: IL-1β and IL-18. Finally, we demonstrate that vildagliptin ameliorates FFA-induced reduced eNOS, indicating its protective role against endothelial dysfunction. Collectively, we conclude that the protective role of vildagliptin in endothelial cells is mediated via suppression of the AMPK-NLRP3 inflammasome-HMGB-1 axis pathway. These findings imply that the anti-diabetic drug vildagliptin possesses dual therapeutic applications in lowering glucose and improving vascular function.

MFN2 silencing promotes neural differentiation of embryonic stem cells via the Akt signaling pathway

Mitofusin 2 (MFN2) is a regulatory protein participating in mitochondria dynamics, cell proliferation, death, differentiation, and so on. This study aims at revealing the functional role of MFN2 in the pluripotency maintenance and primitive differetiation of embryonic stem cell (ESCs). A dox inducible silencing and routine overexpressing approach was used to downregulate and upregulate MFN2 expression, respectively. We have compared the morphology, cell proliferation, and expression level of pluripotent genes in various groups. We also used directed differentiation methods to test the differentiation capacity of various groups. The Akt signaling pathway was explored by the western blot assay. MFN2 upregulation in ESCs exhibited a typical cell morphology and similar cell proliferation, but decreased pluripotent gene markers. In addition, MFN2 overexpression inhibited ESCs differentiation into the mesendoderm, while MFN2 silencing ESCs exhibited a normal cell morphology, slower cell proliferation and elevated pluripotency markers. For differentiation, MFN2 silencing ESCs exhibited enhanced three germs' differentiation ability. Moreover, the protein levels of phosphorylated Akt308 and Akt473 decreased in MFN2 silenced ESCs, and recovered in the neural differentiation process. When treated with the Akt inhibitor, the neural differentiation capacity of the MFN2 silenced ESCs can reverse to a normal level. Taken together, the data indicated that the appropriate level of MFN2 expression is essential for pluripotency and differentiation capacity in ESCs. The increased neural differentiation ability by MFN2 silencing is strongly related to the Akt signaling pathway.

Mitofusin2, as a Protective Target in the Liver, Controls the Balance of Apoptosis and Autophagy in Acute-on-Chronic Liver Failure

Aim: Acute-on-chronic liver failure (ACLF) is closely related to mitochondrial dysfunction. Previous studies showed the vital role of mitofusin2 (Mfn2) in the regulation of mitochondrial function. However, the effect of Mfn2 on ACLF remains unknown. As one of mitochondrial-related pathways, BNIP3-mediated pathway controls the balance between apoptosis and autophagy. However, the relationship between Mfn2 and BNIP3-mediated pathway in ACLF is still obscure. The aim of our study is to clarify the effect of Mfn2 and potential molecular mechanisms in ACLF. Methods: We collected liver tissue from ACLF patients and constructed an ACLF animal model and a hepatocyte autophagy injury model, using adenovirus and lentivirus to deliver Mfn2 and Mfn2-siRNA to liver cells, in order to assess the effect of Mfn2 on autophagy and apoptosis in ACLF. We explored the biological mechanisms of Mfn2-induced autophagy and apoptosis of ACLF through Western blotting, Quantitative Real-Time PCR (RT-PCR), transmission electron microscopy, immunofluorescence, immunohistochemical staining, and hematoxylin-eosin staining. Results: Compared with the normal liver tissue, the expressions of Mfn2, Atg5, Beclin1, and LC3-II/I were significantly decreased and the expression of P62 was much higher in patients with ACLF. Mfn2 significantly attenuated ACLF, characterized via microscopic histopathology and reduced serum AST and ALT levels. Mfn2 promoted the expressions of ATP synthase β, Atg5, Beclin1, LC3-II/I, and Bcl2 and reduced the expressions of P62, Bax, and BNIP3. Conclusions: Mfn2 plays a protective role in the progression of ACLF. BNIP3-mediated signaling pathway is not the only factor associated with Mfn2 controlling the balance of apoptosis and autophagy in ACLF. Mfn2 will provide a promising therapeutic target for patients with ACLF.

Extracellular vesicles degradation pathway based autophagy lysosome pathway

As an ancient intracellular degradation pathway, the autophagy lysosome pathway exists in various cells continuously and stably and maintains cellular homeostasis by degrading damaged organelles and misfolded proteins that are prejudicial to cells. Extracellular vesicles (EVs) including microparticles and exosomes, are derived from varieties of mammalian tissue cells such as platelets, endothelial cells, cardiomyocytes. Through large quantity of active substances carried by EVs, EVs exert momentous biological functions. Recent researches have revealed the molecular mechanism of the interaction between extracellular vesicles and autophagy. In this review, we first elaborate that extracellular vesicles are identified and internalized by target cells by means of receptor-ligand. Since extracellular vesicles contain multiple functional molecules, we subsequently describe the process of intracellular autophagy pathway induced by extracellular vesicles, which activates autophagy-related pathways or delivers autophagy-associated molecules. Finally, we introduced the effects of extracellular vesicle-induced autophagy on extracellular vesicles and target cells respectively. In conclusion, this article integrates relevant theoretical knowledge of autophagy caused by extracellular vesicles and provides a new direction for the study of extracellular vesicles in the future.

Melatonin attenuates myocardial ischemia-reperfusion injury via improving mitochondrial fusion/mitophagy and activating the AMPK-OPA1 signaling pathways

Optic atrophy 1 (OPA1)-related mitochondrial fusion and mitophagy are vital to sustain mitochondrial homeostasis under stress conditions. However, no study has confirmed whether OPA1-related mitochondrial fusion/mitophagy is activated by melatonin and, consequently, attenuates cardiomyocyte death and mitochondrial stress in the setting of cardiac ischemia-reperfusion (I/R) injury. Our results indicated that OPA1, mitochondrial fusion, and mitophagy were significantly repressed by I/R injury, accompanied by infarction area expansion, heart dysfunction, myocardial inflammation, and cardiomyocyte oxidative stress. However, melatonin treatment maintained myocardial function and cardiomyocyte viability, and these effects were highly dependent on OPA1-related mitochondrial fusion/mitophagy. At the molecular level, OPA1-related mitochondrial fusion/mitophagy, which was normalized by melatonin, substantially rectified the excessive mitochondrial fission, promoted mitochondria energy metabolism, sustained mitochondrial function, and blocked cardiomyocyte caspase-9-involved mitochondrial apoptosis. However, genetic approaches with a cardiac-specific knockout of OPA1 abolished the beneficial effects of melatonin on cardiomyocyte survival and mitochondrial homeostasis in vivo and in vitro. Furthermore, we demonstrated that melatonin affected OPA1 stabilization via the AMPK signaling pathway and that blockade of AMPK repressed OPA1 expression and compromised the cardioprotective action of melatonin. Overall, our results confirm that OPA1-related mitochondrial fusion/mitophagy is actually modulated by melatonin in the setting of cardiac I/R injury. Moreover, manipulation of the AMPK-OPA1-mitochondrial fusion/mitophagy axis via melatonin may be a novel therapeutic approach to reduce cardiac I/R injury.

Coenzyme Q10 Ameliorates Pancreatic Fibrosis via the ROS-Triggered mTOR Signaling Pathway

AIM

Pancreatic stellate cells (PSCs) play a pivotal role in pancreatic fibrosis. Any remedies that inhibit the activation of PSCs can be potential candidates for therapeutic strategies in pancreatic fibrosis-related pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis (CP). Our study is aimed at exploring the protective effect of coenzyme Q10 (CoQ10) against pancreatic fibrosis.

METHODS

Pancreatic fibrosis was induced by 20% L-arginine (250 mg/100 g) at 1 h intervals twice per week for 8 weeks in C57BL/6 mice. CoQ10 was administered for 4 weeks. Isolated primary PSCs from C57BL/6 mice were treated with 100 μM CoQ10 for 72 h, as well as Rosup and specific inhibitors. The effects of CoQ10 on the activation of PSCs, autophagy, collagen deposition, histological changes, and oxidative stress were analyzed by western blotting, biochemical estimations, immunofluorescence staining, and hematoxylin-eosin, Masson, and Sirius red staining, as well as with a reactive oxygen species (ROS) assay.

RESULTS

Pretreatment and posttreatment of CoQ10 decreased autophagy, activation of PSCs, oxidative stress, histological changes, and collagen deposition in the CP mouse model. In primary PSCs, expression levels of p-PI3K, p-AKT, and p-mTOR were upregulated with CoQ10. A rescue experiment using specific inhibitors of the PI3K-AKT-mTOR pathway demonstrated that the PI3K-AKT-mTOR signaling pathway was the underlying mechanism by which CoQ10 ameliorated fibrosis. With the addition of Rosup, expression levels of the autophagy biomarkers LC3 and Atg5 were elevated. Meanwhile, the levels of p-PI3K, p-AKT, and p-mTOR were lower.

CONCLUSIONS

Our findings demonstrated that CoQ10 alleviates pancreatic fibrosis by the ROS-triggered PI3K/AKT/mTOR signaling pathway. CoQ10 may be a therapeutic candidate for antifibrotic methods.

Norcantharidin inhibits proliferation and promotes apoptosis via c-Met/Akt/mTOR pathway in human osteosarcoma cells

Osteosarcoma (OS) is the most common malignant bone tumor and frequently affects adolescents. Norcantharidin (NCTD), a demethylated derivative of cantharidin, has been reported to exhibit anticancer activity against various types of tumors but not human OS. The aim of the present study was to evaluate the effects of NCTD on OS cell lines (MG63 and HOS) and to explore the underlying mechanisms. In the present study, the proliferation of OS cells decreased significantly, while the apoptosis was accelerated significantly after exposure to NCTD. Meanwhile, our results also indicated that NCTD could suppress the migration and invasion, decrease the colony‐forming ability and induce S phase cell cycle arrest of OS cells in a dose‐dependent manner. Moreover, our results revealed that the anticancer effects induced by NCTD on OS cells involved autophagy, mitophagy, endoplasmic reticulum stress and c‐Met pathway. Furthermore, the results of animal experiments showed that NCTD inhibited tumor growth in a xenograft model of human OS. These results provide important new insight into the possible molecular mechanisms of NCTD and highlight its potential use as an antitumor drug for human OS.

Dysregulated Mitochondrial Dynamics and Metabolism in Obesity, Diabetes, and Cancer

Metabolism describes the life-sustaining chemical reactions in organisms that provide both energy and building blocks for cellular survival and proliferation. Dysregulated metabolism leads to many life-threatening diseases including obesity, diabetes, and cancer. Mitochondria, subcellular organelles, contain the central energy-producing metabolic pathway, the tricarboxylic acid (TCA) cycle. Also, mitochondria exist in a dynamic network orchestrated by extracellular nutrient levels and intracellular energy needs. Upon stimulation, mitochondria undergo consistent interchange through fusion (small to big) and fission (big to small) processes. Mitochondrial fusion is primarily controlled by three GTPases, mitofusin 1 (Mfn1), Mfn2, and optic atrophy 1 (Opa1), while mitochondrial fission is primarily regulated by GTPase dynamin-related protein 1 (Drp1). Dysregulated activity of these GTPases results in disrupted mitochondrial dynamics and cellular metabolism. This review will update the metabolic roles of these GTPases in obesity, diabetes, and cancer.

Mitofusin-2 acts as biomarker for predicting poor prognosis in hepatitis B virus related hepatocellular carcinoma

OBJECTIVE

To investigate the expression of Mitofusin-2 (MFN2) in HCC tissues and its role in the development of HCC.

METHODS

A total of 107 HCC specimens were collected for tissue microarray analysis and immunohistochemistry (IHC) analysis. The relationship between MFN2 expression and clinical features of patients with HCC was analyzed.

RESULTS

Expression level of MFN2 in HCC tissues was 0.92 ± 0.78, significantly lower than that of matched paracancerous liver tissues (1.25 ± 0.75). Patients with low expression of MFN2 had significantly higher rates of cirrhosis than those with high expression of MFN2 (P = 0.049). Kaplan-Meier survival analysis showed that HCC patients with low expression of MFN2 had a worse prognosis in overall survival than HCC patients with high expression of MFN2 (P = 0.027). Patients with high expression of MFN2 had a better prognosis in disease-free survival compared with HCC patients with low expression of MFN2 (P = 0.047). Vascular invasion and MFN2 expression were shown to be prognostic variables for overall survival in patients with HCC. Multivariate analysis showed that vascular invasion (P < 0.001) and MFN2 expression (P = 0.045) were independent prognostic factors for overall survival. Vascular invasion (P < 0.001) and MFN2 expression (P = 0.042) were independent risk factors associated with disease-free survival.

CONCLUSION

Our data revealed that MFN2 expression was decreased in HCC samples. High MFN2 expression was correlated with longer survival times in patients with HCC and served as an independent factor for better outcomes. Our study therefore provides a promising biomarker for the prognostic prediction of HCC and a potential therapeutic target for the disease.

Neuroprotective Effects of Radix Scrophulariae on Cerebral Ischemia and Reperfusion Injury via MAPK Pathways

Ischemic stroke is a clinically common cerebrovascular disease whose main risks include necrosis, apoptosis and cerebral infarction, all caused by cerebral ischemia and reperfusion (I/R). Ischemia and reperfusion-induced injury or apoptosis inhibition in human brain tissue may exert an irreplaceable protective effect on ischemic nerves. This process has particular significance for the treatment of stroke patients. However, the development of neuroprotective drugs remains challenging. Radix Scrophulariae, traditionally considered a valuable medicine, has been discovered to have neuroprotective effects. To explore the neuroprotective effects of an aqueous extract of Radix Scrophulariae (RSAE) on cerebral ischemia/reperfusion and their underlying mechanisms, oxygen-glucose deprivation and reperfusion (OGD/R)-induced PC12 cells were used, and a middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model was established. In vitro results showed that 12.5 μg/mL RSAE markedly improved cell viability; inhibited LDH leakage; increased SOD, GSH-Px and CAT enzyme activity; stabilized the mitochondrial membrane potential; and reduced OGD-induced cell injury and apoptosis. Additionally, in vivo results preliminarily suggested that in MCAO/R model mice, RSAE treatments attenuated infarct volume; reduced brain water content and nitric oxide (NO) and malondialdehyde (MDA) concentrations; inhibited I/R-induced neurological deficits; reduced the levels of lactate dehydrogenase (LDH) leakage release; improved antioxidant capacity by upregulating SOD, GSH-Px and CAT enzyme activity; and reduced neuronal apoptosis, necrosis and loss of neurons. Moreover, it was found that RSAE upregulated the expression of Bcl-2 and downregulated the expression of Bax. In addition, the phosphorylation levels of MAPK signal pathways were elucidated via western blot analysis and immunohistochemical evaluation. In summary, this study investigated the neuroprotective effects and potential mechanisms of RSAE on focal cerebral I/R injury in mice. Radix Scrophulariae has been previously identified as a potential neuroprotective natural plant. Hence, our results may offer insight into discovering new active compounds or drugs for the treatment of ischemic stroke. Many new natural active chemicals in this extract may be discovered by chemical separation and identification and may provide new insights into therapeutic targets in stroke patients.