Advanced glycation endproducts trigger autophagy in cadiomyocyte via RAGE/PI3K/AKT/mTOR pathway

Availability of Receptors for Advanced Glycation End-Products (RAGE) Influences Differential Transcriptome Expression in Lungs from Mice Exposed to Chronic Secondhand Smoke (SHS)

The receptor for advanced glycation end-products (RAGE) has a central function in orchestrating inflammatory responses in multiple disease states including chronic obstructive pulmonary disease (COPD). RAGE is a transmembrane pattern recognition receptor with particular interest in lung disease due to its naturally abundant pulmonary expression. Our previous research demonstrated an inflammatory role for RAGE following acute exposure to secondhand smoke (SHS). However, chronic inflammatory mechanisms associated with RAGE remain ambiguous. In this study, we assessed transcriptional outcomes in mice exposed to chronic SHS in the context of RAGE expression. RAGE knockout (RKO) and wild-type (WT) mice were delivered nose-only SHS via an exposure system for six months and compared to control mice exposed to room air (RA). We specifically compared WT + RA, WT + SHS, RKO + RA, and RKO + SHS. Analysis of gene expression data from WT + RA vs. WT + SHS showed FEZ1, Slpi, and Msln as significant at the three-month time point; while RKO + SHS vs. WT + SHS identified cytochrome p450 1a1 and Slc26a4 as significant at multiple time points; and the RKO + SHS vs. WT + RA revealed Tmem151A as significant at the three-month time point as well as Gprc5a and Dynlt1b as significant at the three- and six-month time points. Notable gene clusters were functionally analyzed and discovered to be specific to cytoskeletal elements, inflammatory signaling, lipogenesis, and ciliogenesis. We found gene ontologies (GO) demonstrated significant biological pathways differentially impacted by the presence of RAGE. We also observed evidence that the PI3K-Akt and NF-κB signaling pathways were significantly enriched in DEGs across multiple comparisons. These data collectively identify several opportunities to further dissect RAGE signaling in the context of SHS exposure and foreshadow possible therapeutic modalities.

Hirudin inhibit the formation of NLRP3 inflammasome in cardiomyocytes via suppressing oxidative stress and activating mitophagy

Context

Cardiomyocyte hypertrophy due to hemodynamic overload eventually leads to heart failure. Hirudin has been widely used in the treatment of cardiovascular diseases and NLRP3 inflammasome was proven to induce cardiomyocyte pyroptosis. However, the mechanism by which it inhibits cardiomyocyte hypertrophy remains unclear.

Objective

To explore the mechanism of hirudin inhibiting cardiomyocyte hypertrophy based on NLRP3 inflammasome activation and mitophagy.

Materials & methods

1 μM AngII was used for cardiac hypertrophy modeling in H9C2 cells, and cell viability was quantified by CCK-8 assay to screen the appropriate action concentrations of hirudin. After that, we cultured AngII induced-H9C2 cells for 24 h with 0, 0.3, 0.6, and 1.2 mM hirudin, respectively. Next, we marked H9C2 cells with phalloidine and observed them using fluorescence microscope. IL-1β, IL-18, IL-6, TNF-α, ANP, BNP, β-MHC, and mtDNA were analyzed by qRT-PCR; ROS were quantified by Flow cytometry; SOD, MDA, and GSH-Px were detected by ELISA; and proteins including NLRP3, ASC, caspase-1, pro-caspase-1, IL-1β, IL-18, PINK-1, Parkin, beclin-1, LC3-Ⅰ, LC3-Ⅱ, p62, were quantified by western blotting.

Results

It was discovered that hirudin reduced the superficial area of AngII-induced H9C2 cells and inhibited the AngII-induced up-regulation of ANP, BNP, and β-MHC. Besides, hirudin down-regulated the expressions of NLRP3 inflammasome-related cytokines, containing IL-1β, IL-18, IL-6, TNF-α. It also down-regulated the expression of mtDNA and ROS, decreased the expression levels of NLRP3 inflammasome activation related proteins, including NLRP3, ASC, caspase-1, pro-caspase-1, IL-1β, IL-18; and increased the expressions of PINK-1, Parkin, beclin-1, LC3-Ⅱ/LC3-Ⅰ, p62 in AngII-induced H9C2 cells.

Discussion

Hirudin promoted the process of mitophagy, inhibited the development of inflammation and oxidative stress, and inhibited the activation of the NLRP3 inflammasome and the PINK-1/Parkin pathway.

Conclusion

Hirudin has the activity to suppress cardiac hypertrophy may benefit from the inhibition of NLRP3 inflammasome and activating of PINK-1/Parkin related-mitophagy.

The lncRNA Sweetheart regulates compensatory cardiac hypertrophy after myocardial injury in murine males

After myocardial infarction in the adult heart the remaining, non-infarcted tissue adapts to compensate the loss of functional tissue. This adaptation requires changes in gene expression networks, which are mostly controlled by transcription regulating proteins. Long non-coding transcripts (lncRNAs) are taking part in fine-tuning such gene programs. We describe and characterize the cardiomyocyte specific lncRNA Sweetheart RNA (Swhtr), an approximately 10 kb long transcript divergently expressed from the cardiac core transcription factor coding gene Nkx2-5. We show that Swhtr is dispensable for normal heart development and function but becomes essential for the tissue adaptation process after myocardial infarction in murine males. Re-expressing Swhtr from an exogenous locus rescues the Swhtr null phenotype. Genes that depend on Swhtr after cardiac stress are significantly occupied and therefore most likely regulated by NKX2-5. The Swhtr transcript interacts with NKX2-5 and disperses upon hypoxic stress in cardiomyocytes, indicating an auxiliary role of Swhtr for NKX2-5 function in tissue adaptation after myocardial injury.

Non-apoptotic programmed cell deaths in diabetic pulmonary dysfunction: the new side of advanced glycation end products

Diabetes mellitus (DM) is a chronic metabolic disorder that affects multiple organs and systems, including the pulmonary system. Pulmonary dysfunction in DM patients has been observed and studied for years, but the underlying mechanisms have not been fully understood. In addition to traditional mechanisms such as the production and accumulation of advanced glycation end products (AGEs), angiopathy, tissue glycation, oxidative stress, and systemic inflammation, recent studies have focused on programmed cell deaths (PCDs), especially the non-apoptotic ones, in diabetic pulmonary dysfunction. Non-apoptotic PCDs (NAPCDs) including autophagic cell death, necroptosis, pyroptosis, ferroptosis, and copper-induced cell death have been found to have certain correlations with diabetes and relevant complications. The AGE-AGE receptor (RAGE) axis not only plays an important role in the traditional pathogenesis of diabetes lung disease but also plays an important role in non-apoptotic cell death. In this review, we summarize novel studies about the roles of non-apoptotic PCDs in diabetic pulmonary dysfunction and focus on their interactions with the AGE-RAGE axis.

Advanced glycation end products are associated with cardiovascular risk in the Mexican population

BACKGROUND AND AIMS

Chronic exposure to hyperglycemia is a significant risk factor for cardiovascular disease (CVD). Advanced glycation end products (AGES) result from multiple sugar-dependent reactions interacting with proteins and their receptors, generating endothelial dysfunction and CVD. However, there is little epidemiological data about its impact on CVD risk. We aimed to assess the association between circulating AGES and CVD risk in the Mexican population.

METHODS AND RESULTS

We used longitudinal data from waves 2004-2006 and 2010-2012 of 1195 participants from the Health Workers Cohort Study. Circulating AGES were assessed by radioimmunoassay, and cardiovascular risk (CVR) was computed with the Framingham risk score. Linear and logistic fixed-effects regression models were used to assess the interest association, adjusting for confounding factors. An increase in 200 μU/ml of AGES was associated with a 0.18% increased risk of CVD (95% CI 0.05-0.31%). After adjusting for physical activity and smoking status, individuals who increased their AGES category had higher odds of middle-high CVR (low to medium AGES: OR 1.83, 95% CI 1.11-3.20; low to high AGES: OR 2.61, 95% CI 1.51-4.50). The associations remained statistically significant when we further adjusted for insulin resistance, dietary intake of AGES, and total daily calorie intake.

CONCLUSION

Our data show that circulating AGES are associated with the Framingham CVD risk score, independently of other major risk factors for CVD in the Mexican population.

Endothelial Autophagy Dysregulation in Diabetes

Diabetes mellitus is a major public health issue that affected 537 million people worldwide in 2021, a number that is only expected to increase in the upcoming decade. Diabetes is a systemic metabolic disease with devastating macro- and microvascular complications. Endothelial dysfunction is a key determinant in the pathogenesis of diabetes. Dysfunctional endothelium leads to vasoconstriction by decreased nitric oxide bioavailability and increased expression of vasoconstrictor factors, vascular inflammation through the production of pro-inflammatory cytokines, a loss of microvascular density leading to low organ perfusion, procoagulopathy, and/or arterial stiffening. Autophagy, a lysosomal recycling process, appears to play an important role in endothelial cells, ensuring endothelial homeostasis and functions. Previous reports have provided evidence of autophagic flux impairment in patients with type I or type II diabetes. In this review, we report evidence of endothelial autophagy dysfunction during diabetes. We discuss the mechanisms driving endothelial autophagic flux impairment and summarize therapeutic strategies targeting autophagy in diabetes.

Dysfunctional gene splicing in glucose metabolism may contribute to Alzheimer's disease

ABSTRACT

The glucose metabolism is crucial for sustained brain activity as it provides energy and is a carbon source for multiple biomacromolecules; glucose metabolism decreases dramatically in Alzheimer's disease (AD) and may be a fundamental cause for its development. Recent studies reveal that the alternative splicing events of certain genes effectively regulate several processes in glucose metabolism including insulin receptor, insulin-degrading enzyme, pyruvate kinase M, receptor for advanced glycation endproducts, and others, thereby, influencing glucose uptake, glycolysis, and advanced glycation end-products-mediated signaling pathways. Indeed, the discovery of aberrant alternative splicing that changes the proteomic diversity and protein activity in glucose metabolism has been pivotal in our understanding of AD development. In this review, we summarize the alternative splicing events of the glucose metabolism-related genes in AD pathology and highlight the crucial regulatory roles of splicing factors in the alternative splicing process. We also discuss the emerging therapeutic approaches for targeting splicing factors for AD treatment.

The receptor for advanced glycation end products (RAGE) is involved in mitochondrial function and cigarette smoke-induced oxidative stress

The mechanisms underlying muscle dysfunction with Chronic Obstructive Pulmonary Disease (COPD) are poorly understood. Indirect evidence has recently suggested a role of Advanced Glycation End Products (AGEs) and their receptor (RAGE) in the pathophysiology of COPD. Accordingly, this study aimed to examine the redox balance and mitochondrial alterations in the skeletal muscle of a mouse model deficient in the receptor for AGE (RAGE-KO) and wild-type C57BL/6 exposed to cigarette smoke for 8-months using immunoblotting, spectrophotometry, and high-resolution respirometry. Cigarette smoke exposure increased by two-fold 4-HNE levels (P < 0.001), a marker of oxidative stress, and markedly downregulated contractile proteins, mitochondrial respiratory complexes, and uncoupling proteins levels (P < 0.001). Functional alterations with cigarette smoke exposure included a greater reliance on complex-I supported respiration (P < 0.01) and lower relative respiratory capacity for fatty acid (P < 0.05). RAGE knockout resulted in 47% lower 4-HNE protein levels than the corresponding WT control mice exposed to cigarette smoke (P < 0.05), which was partly attributed to increased Complex III protein levels. Independent of cigarette smoke exposure, RAGE KO decreased mitochondrial specific maximal respiration (P < 0.05), resulting in a compensatory increase in mitochondrial content measured by citrate synthase activity (P < 0.001) such that muscle respiratory capacity remained unaltered. Together, these findings suggest that knockout of RAGE protected the skeletal muscle against oxidative damage induced by 8 months of cigarette smoke exposure. In addition, this study supports a role for RAGE in regulating mitochondrial content and function and can thus serve as a potential therapeutic target.

ATF3/SPI1/SLC31A1 Signaling Promotes Cuproptosis Induced by Advanced Glycosylation End Products in Diabetic Myocardial Injury

Cuproptosis resulting from copper (Cu) overload has not yet been investigated in diabetic cardiomyopathy (DCM). Advanced glycosylation end products (AGEs) induced by persistent hyperglycemia play an essential role in cardiotoxicity. To clarify whether cuproptosis was involved in AGEs-induced cardiotoxicity, we analyzed the toxicity of AGEs and copper in AC16 cardiomyocytes and in STZ-induced or db/db-diabetic mouse models. The results showed that copper ionophore elesclomol induced cuproptosis in cardiomyocytes. It was only rescued by copper chelator tetrathiomolybdate rather than by other cell death inhibitors. Intriguingly, AGEs triggered cardiomyocyte death and aggravated it when incubated with CuCl₂ or elesclomol-CuCl2. Moreover, AGEs increased intracellular copper accumulation and exhibited features of cuproptosis, including loss of Fe-S cluster proteins (FDX1, LIAS, NDUFS8 and ACO2) and decreased lipoylation of DLAT and DLST. These effects were accompanied by decreased mitochondrial oxidative respiration, including downregulated mitochondrial respiratory chain complex, decreased ATP production and suppressed mitochondrial complex I and III activity. Additionally, AGEs promoted the upregulation of copper importer SLC31A1. We predicted that ATF3 and/or SPI1 might be transcriptional factors of SLC31A1 by online databases and validated that by ATF3/SPI1 overexpression. In diabetic mice, copper and AGEs increases in the blood and heart were observed and accompanied by cardiac dysfunction. The protein and mRNA profile changes in diabetic hearts were consistent with cuproptosis. Our findings showed, for the first time, that excessive AGEs and copper in diabetes upregulated ATF3/SPI1/SLC31A1 signaling, thereby disturbing copper homeostasis and promoting cuproptosis. Collectively, the novel mechanism might be an alternative potential therapeutic target for DCM.

Spontaneous NETosis in diabetes: A role of hyperglycemia mediated ROS and autophagy

Type 2-diabetes, particularly poorly controlled diabetes, is a risk factor for several infections such as lower respiratory tract and skin infections. Hyperglycemia, a characteristic downstream effect of poorly controlled diabetes, has been shown to impair the function of immune cells, in particular neutrophils. Several studies have demonstrated that hyperglycemia-mediated priming of NADPH oxidase results in subsequent elevated levels of reactive oxygen species (ROS). In healthy neutrophils, ROS plays an important role in pathogen killing by phagocytosis and by induction of Neutrophil Extracellular Traps (NETs). Given the key role of ROS in autophagy, phagocytosis and NETosis, the relationship between these pathways and the role of diabetes in the modulation of these pathways has not been explored previously. Therefore, our study aimed to understand the relationship between autophagy, phagocytosis and NETosis in diabetes. We hypothesized that hyperglycemia-associated oxidative stress alters the balance between phagocytosis and NETosis by modulating autophagy. Using whole blood samples from individuals with and without type 2-diabetes (in the presence and absence of hyperglycemia), we demonstrated that (i) hyperglycemia results in elevated levels of ROS in neutrophils from those with diabetes, (ii) elevated levels of ROS increase LCIII (a marker for autophagy) and downstream NETosis. (iii) Diabetes was also found to be associated with low levels of phagocytosis and phagocytic killing of S. pneumoniae. (iv) Blocking either NADPH oxidase or cellular pathways upstream of autophagy led to a significant reduction in NETosis. This study is the first to demonstrate the role of ROS in altering NETosis and phagocytosis by modulating autophagy in type 2-diabetes. GRAPHICAL ABSTRACT.

Endothelial-to-mesenchymal transition: An underappreciated mediator of diabetic complications

Diabetes and its complications represent a great burden on the global healthcare system. Diabetic complications are fundamentally diseases of the vasculature, with endothelial cells being the centerpiece of early hyperglycemia-induced changes. Endothelial-to-mesenchymal transition is a tightly regulated process that results in endothelial cells losing endothelial characteristics and developing mesenchymal traits. Although endothelial-to-mesenchymal transition has been found to occur within most of the major complications of diabetes, it has not been a major focus of study or a common target in the treatment or prevention of diabetic complications. In this review we summarize the importance of endothelial-to-mesenchymal transition in each major diabetic complication, examine specific mechanisms at play, and highlight potential mechanisms to prevent endothelial-to-mesenchymal transition in each of the major chronic complications of diabetes.

LncRNA MEG3: Potential stock for precision treatment of cardiovascular diseases

The prevalence and mortality rates of cardiovascular diseases are increasing, and new treatment strategies are urgently needed. From the perspective of basic pathogenesis, the occurrence and development of cardiovascular diseases are related to inflammation, apoptosis, fibrosis and autophagy of cardiomyocytes, endothelial cells and other related cells. The involvement of maternally expressed gene 3 (MEG3) in human disease processes has been increasingly reported. P53 and PI3K/Akt are important pathways by which MEG3 participates in regulating cell apoptosis. MEG3 directly or competitively binds with miRNA to participate in apoptosis, inflammation, oxidative stress, endoplasmic reticulum stress, EMT and other processes. LncRNA MEG3 is mainly involved in malignant tumors, metabolic diseases, immune system diseases, cardiovascular and cerebrovascular diseases, etc., LncRNA MEG3 has a variety of pathological effects in cardiomyocytes, fibroblasts and endothelial cells and has great clinical application potential in the prevention and treatment of AS, MIRI, hypertension and HF. This paper will review the research progress of MEG3 in the aspects of mechanism of action, other systemic diseases and cardiovascular diseases, and point out its great potential in the prevention and treatment of cardiovascular diseases. lncRNAs also play a role in endothelial cells. In addition, lncRNA MEG3 has shown biomarker value, prognostic value and therapeutic response measurement in tumor diseases. We boldly speculate that MEG3 will play a role in the emerging discipline of tumor heart disease.

Receptor for Advanced Glycation End Products (RAGE): A Pivotal Hub in Immune Diseases

As a critical molecule in the onset and sustainment of inflammatory response, the receptor for advanced glycation end products (RAGE) has a variety of ligands, such as advanced glycation end products (AGEs), S100/calcium granule protein, and high-mobility group protein 1 (HMGB1). Recently, an increasing number studies have shown that RAGE ligand binding can initiate the intracellular signal cascade, affect intracellular signal transduction, stimulate the release of cytokines, and play a vital role in the occurrence and development of immune-related diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and Alzheimer’s disease. In addition, other RAGE signaling pathways can play crucial roles in life activities, such as inflammation, apoptosis, autophagy, and endoplasmic reticulum stress. Therefore, the strategy of targeted intervention in the RAGE signaling pathway may have significant therapeutic potential, attracting increasing attention. In this paper, through the systematic induction and analysis of RAGE-related signaling pathways and their regulatory mechanisms in immune-related diseases, we provide theoretical clues for the follow-up targeted intervention of RAGE-mediated diseases.

Multi-Omics-Based Autophagy-Related Untypical Subtypes in Patients with Cerebral Amyloid Pathology

Recent multi-omics analyses paved the way for a comprehensive understanding of pathological processes. However, only few studies have explored Alzheimer's disease (AD) despite the possibility of biological subtypes within these patients. For this study, unsupervised classification of four datasets (genetics, miRNA transcriptomics, proteomics, and blood-based biomarkers) using Multi-Omics Factor Analysis+ (MOFA+), along with systems-biological approaches following various downstream analyses are performed. New subgroups within 170 patients with cerebral amyloid pathology (Aβ+) are revealed and the features of them are identified based on the top-rated targets constructing multi-omics factors of both whole (M-TPAD) and immune-focused models (M-IPAD). The authors explored the characteristics of subtypes and possible key-drivers for AD pathogenesis. Further in-depth studies showed that these subtypes are associated with longitudinal brain changes and autophagy pathways are main contributors. The significance of autophagy or clustering tendency is validated in peripheral blood mononuclear cells (PBMCs; n = 120 including 30 Aβ- and 90 Aβ+), induced pluripotent stem cell-derived human brain organoids/microglia (n = 12 including 5 Aβ-, 5 Aβ+, and CRISPR-Cas9 apolipoprotein isogenic lines), and human brain transcriptome (n = 78). Collectively, this study provides a strategy for precision medicine therapy and drug development for AD using integrative multi-omics analysis and network modelling.

Proximal tubular RAGE mediated the renal fibrosis in UUO model mice via upregulation of autophagy

Previous studies reported that RAGE participated in the process of kidney fibrosis, but the function and regulation pathway of RAGE in proximal tubular cells in this process remains unclear. Here, we found that expression of RAGE was increased by TGF-β1 treatment and unilateral ureteral obstruction (UUO). Knock down of RAGE ameliorated renal fibrosis by TGF-β1 treatment, the expression of vimentin, Collagen I&III, and fibronectin are decreased. Mechanistically, RAGE mediated TGF-β1-induced phosphorylation of Stat3 and directly upregulated the Atg7 to increase the level of autophagy, and ultimately resulting in renal fibrosis. Furthermore, PT-RAGE-KO mice reduced kidney fibrosis in UUO model via inhibiting Stat3/Atg7 axis by knocking down RAGE. Furthermore, the above findings were confirmed in kidney of patients with obstructive nephropathy. Collectively, RAGE in proximal tubular cells promotes the autophagy to increase renal fibrosis via upregulation of Stat3/Atg7 axis.

A novel lncRNA lnc-PPRL promotes pterygium development by activating PI3K/PDK1 signaling pathway

A sight threatening, pterygium is a common proliferative and degenerative disease of the ocular surface. LncRNAs have been widely studied in the occurrence and development of various diseases, however, the study of lncRNAs in pterygium has just relatively lacking. In the present study, we performed the high-throughput RNA sequencing (HTS) technology to identify differentially expressed lncRNAs in pterygium. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were carried out to forecast the regulatory and functional role of lncRNAs in pterygium. Notably, we identified a novel lncRNA, LOC102724238, which we named pterygium positively-related lncRNA (lnc-PPRL), was up-regulated in pterygium. Lnc-PPRL showed to be preferentially accumulated in cytoplasm, and it can promote cell proliferation, migration and invasion of human pterygium epithelium cells (hPECs). Further study of underlying mechanisms demonstrated that lnc-PPRL may exert its biological effect by activating canonical PI3K/PDK1 pathway, and subsequently promoting the activation of Akt/mTOR signaling pathway and its downstream effectors. Interestingly, lnc-PPRL was also proved to influence YAP nuclear localization. Taken together, our study firstly suggested that the "big molecule" lnc-PPRL have potential as a novel therapeutic target for the prevention and treatment of pterygium.

Salvia miltiorrhiza prevents methylglyoxal-induced glucotoxicity via the regulation of apoptosis-related pathways and the glyoxalase system in human umbilical vein endothelial cells

Methylglyoxal (MGO), which is produced as a byproduct of glucose metabolism, is the leading to diabetic cardiovascular complications. Salvia miltiorrhiza Bunge (Lamiaceae) has been reported as a potential plant to control diabetes and cardiovascular disease. However, no report exists on the effect of Salvia miltiorrhiza Bunge extract (SME) on MGO-induced glucotoxicity in human umbilical vein endothelial cells (HUVECs).We demonstrated the protective effects of SME (1, 5, and 10 µg/mL) and its components against MGO-induced endothelial dysfunction in HUVECs. Cytotoxicity was evaluated using the several in vitro experiments. Additionally, the protein expression of receptor of advanced glycation end-products (RAGE), mitogen-activated protein kinase (MAPK) pathway and glyoxalase system were measured. Then, the inhibitory effects of SME and its main components on MGO-induced oxidative stress, radical scavenging, formation of MGO-derived advanced glycation end products (AGEs), and MGO-AGEs crosslinking were evaluated.SME (10 µg/mL) strongly prevented expressed levels of RAGE, MGO-induced apoptosis and reduced ROS generation in HUVECs, comparing with 1 mM aminoguanidine. Additionally, SME (5 and 10 µg/mL) reduced the expression of proteins (e.g., p-ERK and p-p38) in the MAPKs pathway and upregulated the glyoxalase system in HUVECs. SME (0.5 - 10 mg/mL), dihydrotanshinone (0.4 mM), and rosmarinic acid (0.4 mM) prevented MGO-AGEs formation and broke the MGO-AGE crosslinking. These results show that S. miltiorrhiza has protective effects against MGO-induced glucotoxicity by regulating the proteins involved in apoptosis, glyoxalase system and antioxidant activity.We expect that S. miltiorrhiza is a potential natural resource for the treatment of MGO-induced vascular endothelial dysfunction.

Nonmonotonic response of type 2 diabetes by low concentration organochlorine pesticide mixture: Findings from multi-omics in zebrafish

Exposure to a single organochlorine pesticide (OCP) at high concentration and over a short period of exposure constrain our understanding of the contribution of chemical exposure to type 2 diabetes (T2D). A total of 450 male and female zebrafish was exposed to mixtures of five OCPs at 0, 0.05, 0.25, 2.5, and 25 μg/L for 12 weeks. T2D-related hematological parameters (i.e., glucose, insulin, free fatty acid, and triglycerides) and mitochondrial complex I to IV activities were assessed. Metabolomics, proteomics, and transcriptomics were analyzed in female livers, and their data-driven integration was performed. High fasting glucose and low insulin levels were observed only at 0.05 μg/L of the OCP mixture in females, indicating a nonlinear and sexually dependent response. We found that exposure to the OCP mixture inhibited the activities of mitochondrial complexes, especially III and IV. Combining individual and integrated omics analysis, T2D-linked metabolic pathways that regulate mitochondrial function, insulin signaling, and energy homeostasis were altered by the OCP mixture, which explains the observed phenotypic hematological effects. We demonstrated the cause-and-effect relationship between exposures to OCP mixture and T2D using zebrafish model. This study gives an insight into mechanistic research of metabolic diseases caused by chemical exposure using zebrafish.

Autophagy upregulates inflammatory cytokines in gingival tissue of patients with periodontitis and lipopolysaccharide-stimulated human gingival fibroblasts

Background

Periodontitis is an inflammatory disease caused by multiple disease‐associated bacterial species in periodontal tissues. Autophagy is known to modulate various inflammation‐driven diseases and inflammatory responses, but the role of autophagy related to the pathogenesis of periodontitis is not fully established. We investigated whether autophagic flux regulated the expression of inflammatory cytokines in the gingiva of periodontitis patients and lipopolysaccharide (LPS)‐stimulated human gingival fibroblasts (HGFs) and the underlying mechanism.

Methods

The mRNA and protein expression of proinflammatory cytokines was assessed in human gingival tissues collected from patients with periodontitis and HGFs treated with LPS. The expression of signaling molecules related to autophagy was evaluated by immunofluorescence and Western blot analyses.

Results

The expression of interleukin (IL)‐6, tumor necrosis factor‐α (TNF‐α), cyclooxygenase‐2 (COX‐2), and intercellular adhesion molecule‐1 (ICAM‐1) was increased in the gingival tissues of patients with periodontitis. LC3B‐positive cells, a typical autophagic marker, were increased in the gingival tissues of periodontitis patients and LPS‐treated HGFs. The conversion ratio of LC3‐I to LC3‐II was higher in the gingival tissues associated with periodontitis and LPS‐treated HGFs compared to the controls. The autophagy inhibitor 3‐methyladenine (3MA) significantly abrogated the LPS‐sustained inflammatory effect by reducing the expression of IL‐6, TNF‐α, COX‐2, and ICAM‐1 in HGFs. The phosphorylation of protein kinase B (AKT) and protein S6K1 (S6), signals involved in the mTOR‐dependent mechanism, was decreased in gingiva derived from periodontitis patients and LPS‐treated HGFs.

Conclusions

Autophagy augmented the production of inflammatory cytokines by mTOR inactivation via the AKT signaling pathway in the gingival tissues of patients with periodontitis and LPS‐stimulated HGFs. These findings would provide a better understanding of the mechanism by which autophagy regulates the inflammatory response associated with periodontal pathogenesis.

Expression of autophagy and apoptosis-related factors in the periodontal tissue of experimental diabetic rats: a histomorphometric, microtomographic and immunohistochemical study

Objective

This study aimed to investigate the expression of autophagy-related factors microtubule-associated protein l light chain 3 (LC3) and the apoptosis-related factors BCL2-associated X protein (Bax) and B cell lymphoma-2 (Bcl-2) in the periodontal tissue of experimental diabetic rats. These data were used to explore the potential mechanism in diabetes-induced periodontal tissue lesions.

Methods

A total of 32 Sprague Dawley (SD) rats were randomly assigned into diabetes (group D, n = 16) and control groups (group N, n = 16). The diabetic group was induced by intraperitoneal injection of 1% streptozotocin (STZ, 60 mg/kg) and the control group was injected with citrate buffer (0.1mol/L). Rats were sacrificed after 4 and 8 weeks of feeding and collected as D1, N1 groups and D2, N2 groups, and the maxilla were retained for analysis. The changes in periodontal tissue structure were observed by hematoxylin-eosin (HE) staining. The expression and distribution of LC3, Bax and Bcl-2 in the periodontium of the rats was detected by immunohistochemical (SP) staining.

Results

Diabetic rats showed several changes compared to control animals including sparse alveolar bone trabecular structure, loss of the lamina dura and absorption of the local alveolar bone. The positive expression level of LC3 in the gingival epithelial, periodontal ligament and alveolar bone of group D1 was significantly higher than in the N1, N2 and D2 groups (P < 0.05). The level of Bax expression in the group D2 rats was significantly higher than those in the N1, N2 and D1 groups (P < 0.05), while the positive degree of Bcl-2 was significantly lower than those of other groups (P < 0.001). LC3 was negatively correlated with Bax and was irrelevant with Bcl-2; Bcl-2 was not correlated with Bax.

Conclusions

The expression of LC3, Bax and Bcl-2 changes in the periodontal tissue of diabetic rats may indicate that autophagy and apoptotic are involved in the process of periodontal tissue damage in diabetic rats. These changes may be one of the mechanisms of periodontal tissue lesions.

Curcumin-mediated photodynamic therapy inhibits the phenotypic transformation, migration, and foaming of oxidized low-density lipoprotein-treated vascular smooth muscle cells by promoting autophagy

Supplemental Digital Content is Available in the Text.

Vascular smooth muscle cells (VSMCs) are becoming a hot spot and target of atherosclerosis research. This study aimed to observe the specific effects of curcumin (CUR)-mediated photodynamic therapy (CUR-PDT) on oxidized low-density lipoprotein (ox-LDL)-treated VSMCs and confirm whether these effects are mediated by autophagy. In this study, the mouse aortic smooth muscle cell line and A7r5 cell lines were used for parallel experiments. VSMC viability was evaluated by Cell Counting Kit-8 assay. VSMCs were treated with ox-LDL to establish a model of atherosclerosis in vitro. The autophagy level and the expression of proteins related to phenotypic transformation were detected by western blotting. The migration ability of the cells was detected by using transwell assay. The presence of intracellular lipid droplets was detected by Oil Red O staining. The results showed that VSMCs transformed from the contraction phenotype to the synthetic phenotype when stimulated by ox-LDL, during which autophagy was inhibited. However, CUR-PDT treatment significantly promoted the level of autophagy and inhibited the process of phenotypic transformation induced by ox-LDL. In addition, ox-LDL significantly promoted VSMC migration and increased the number of lipid droplets, whereas CUR-PDT treatment significantly reduced the ox-LDL-induced increase in the migration ability of, and lipid droplet numbers in, VSMCs. When the VSMCs were pretreated with the autophagy inhibitor 3-methyladenine for 24 hours, the effects of CUR-PDT were reversed. Therefore, our study indicated that CUR-PDT can inhibit the phenotypic transformation, migration, and foaming of ox-LDL–treated VSMCs by inducing autophagy.

Knockout RAGE alleviates cardiac fibrosis through repressing endothelial-to-mesenchymal transition (EndMT) mediated by autophagy

Endothelial-to-mesenchymal transition (EndMT) has been shown to contribute to cardiac fibrosis and heart failure (HF). Recent studies have demonstrated that EndMT is regulated by autophagy, and we previously showed suppression of excessive autophagy and alleviation of cardiac fibrosis in HF mice with inactivated receptor for advanced glycation end products (RAGE). Thus, we investigated whether reduced cardiac fibrosis due to RAGE knockout occurred by inhibiting EndMT mediated by excessive autophagy. We found a decrease in endothelial cells (CD31+/VE-Cadherin+) and an increase in cells co-expressing CD31 and α-smooth muscle actin (α-SMA, myofibroblast marker) at 8 weeks in heart tissue of mice subjected to transverse aortic constriction (TAC), which implied EndMT. Knockout RAGE decreased EndMT accompanied by decreased expression of autophagy-related proteins (LC3BII/I and Beclin 1), and alleviated cardiac fibrosis and improved cardiac function in TAC mice. Moreover, 3-methyladenine (3-MA) and chloroquine (CQ), inhibitors of autophagy, attenuated EndMT, and cardiac fibrosis in TAC mice. Importantly, EndMT induced by AGEs could be blocked by autophagy inhibitor in vivo and in vitro. These results suggested that AGEs/RAGE-autophagy-EndMT axis involved in the development of cardiac fibrosis and knockout RAGE ameliorated cardiac fibrosis through decreasing EndMT regulated by autophagy, which could be a promising therapeutic strategy for HF.

Fluorochloridone induces autophagy in TM4 Sertoli cells: involvement of ROS-mediated AKT-mTOR signaling pathway

BACKGROUND

Fluorochloridone (FLC), a selective pyrrolidone herbicide, has been recognized as a potential endocrine disruptor and reported to induce male reproductive toxicity, but the underlying mechanism is unclear. The aim of this study was to investigate the mechanism of FLC-induced reproductive toxicity on male mice with particular emphasis on the role of autophagy in mice' TM4 Sertoli cells.

METHODS

Adult C57BL/6 mice were divided into one control group (0.5% sodium carboxymethyl cellulose), and four FLC-treated groups (3,15,75,375 mg/kg). The animals (ten mice per group) received gavage for 28 days. After treatment, histological analysis, sperm parameters, the microstructure of autophagy and the expression of autophagy-associated proteins in testis were evaluated. Furthermore, to explore the autophagy mechanism, TM4 Sertoli cells were treated with FLC (0,40,80,160 μM) in vitro for 24 h. Cell activity and cytoskeletal changes were measured by MTT assay and F-actin immunofluorescence staining. The formation of autophagosome, accumulation of reactive oxygen species (ROS), expression of autophagy marker proteins (LC3, Beclin-1 and P62) and AKT-related pathway proteins (AKT, mTOR) were observed. The ROS scavenger N-acetylcysteine (NAC) and AKT agonist (SC79) were used to treat TM4 cells to observe the changes of AKT-mTOR pathway and autophagy.

RESULTS

In vivo, it showed that FLC exposure caused testicular injuries, abnormality in epididymal sperm. Moreover, FLC increased the formation of autophagosomes, the accumulation of LC3II/LC3I, Beclin-1 and P62 protein, which is related to the degradation of autophagy. In vitro, FLC triggered TM4 cell autophagy by increasing the formation of autophagosomes and upregulating of LC3II/LC3I, Beclin-1 and P62 levels. In addition, FLC induced ROS production and inhibited the activities of AKT and mTOR kinases. The Inhibition of AKT/mTOR signaling pathways and the activation of autophagy induced by FLC could be efficiently reversed by pretreatment of NAC. Additionally, decreased autophagy and increased cell viability were observed in TM4 cells treated with SC79 and FLC, compared with FLC alone, indicating that FLC-induced autophagy may be pro-death.

CONCLUSION

Taken together, our study provided the evidence that FLC promoted autophagy in TM4 Sertoli cells and that this process may involve ROS-mediated AKT/mTOR signaling pathways.

Rapamycin alleviates cognitive impairment in murine vascular dementia: The enhancement of mitophagy by PI3K/AKT/mTOR axis

There are no approved symptomatic treatments for vascular dementia (VaD). Rapamycin (RAPA) improves cognitive deficits in Alzheimer's disease rats. To explore whether RAPA improves cognitive impairment after VaD and its possible molecular mechanisms. Thirty Sprague Dawley rats were randomly divided into three groups: sham (received sham-operation), VaD model (received permanent ligation of bilateral carotid arteries) and RAPA (7.5 mg/kg) treatment. Cognitive function was evaluated by Morris water maze test. Neuronal apoptosis was evaluated by TUNEL staining. Mitophagy was assessed by mitochondrial DNA (mtDNA), ATP level, transmission electron microscope and mitophagy-associated proteins. Proteins were quantified by Western blot and immunofluorescence. BV2 cells were exposed to RAPA or/and MHY1485 (mTOR activator) to verify in vivo results. Compared to VaD rats, the escape latency of RAPA-treated rats was significantly decreased, and time spent in target quadrant was longer. Pathologic changes, mitochondrial dysfunction, increase of neuronal apoptosis and related proteins in VaD rats were remarkably alleviated by RAPA. After RAPA treatment, an increase in number of autophagosomes was observed, along with up-regulation of mitophagy-related proteins. Overexpression of PI3K, AKT and mTOR were suppressed by RAPA treatment. In vitro experiments confirmed effects of RAPA, and demonstrated that MHY1485 addition reversed the RAPA-caused apoptosis inhibition and mitophagy enhancement. Overall, RAPA improved the cognitive impairment of VaD rats, alleviated neuronal injury and mitochondrial dysfunction. We proposed a potential mechanism that RAPA may play improving role by inhibiting neuronal apoptosis and enhancing mitophagy through PI3K/AKT/mTOR pathway. Findings provided an exciting possibility for novel treatment strategy of VaD.

RAGE: A potential therapeutic target during FGF1 treatment of diabetes-mediated liver injury

As a serious metabolic disease, diabetes causes series of complications that seriously endanger human health. The liver is a key organ for metabolizing glucose and lipids, which substantially contributes to the development of insulin resistance and type 2 diabetes mellitus (T2DM). Exogenous fibroblast growth factor 1 (FGF1) has a great potential for the treatment of diabetes. Receptor of advanced glycation end products (RAGE) is a receptor for advanced glycation end products that involved in the development of diabetes‐triggered complications. Previous study has demonstrated that FGF1 significantly ameliorates diabetes‐mediated liver damage (DMLD). However, whether RAGE is involved in this process is still unknown. In this study, we intraperitoneally injected db/db mice with 0.5 mg/kg FGF1. We confirmed that FGF1 treatment not only significantly ameliorates diabetes‐induced elevated apoptosis in the liver, but also attenuates diabetes‐induced inflammation, then contributes to ameliorate liver dysfunction. Moreover, we found that diabetes triggers the elevated RAGE in hepatocytes, and FGF1 treatment blocks it, suggesting that RAGE may be a key target during FGF1 treatment of diabetes‐induced liver injury. Thus, we further confirmed the role of RAGE in FGF1 treatment of AML12 cells under high glucose condition. We found that D‐ribose, a RAGE agonist, reverses the protective role of FGF1 in AML12 cells. These findings suggest that FGF1 ameliorates diabetes‐induced hepatocyte apoptosis and elevated inflammation via suppressing RAGE pathway. These results suggest that RAGE may be a potential therapeutic target for the treatment of DMLD.

Role of PI3-Kinase in Angiotensin II-Induced Cardiac Hypertrophy: Class I Versus Class III

Cardiac hypertrophy is an adaptive response to cardiac overload initially but turns into a decompensated condition chronically, leading to heart failure and sudden cardiac death. The molecular mechanisms involved in cardiac hypertrophy and the signaling pathways that contribute to the switch from compensation to decompensation are not fully clear. The aim of the current study was to examine the role of PI3-kinases Class I (PI3KC1) and Class III (PI3KC3) in angiotensin (Ang) II-induced cardiac hypertrophy. The results demonstrate that treatment of cardiomyocytes with Ang II caused dose-dependent increases in autophagy, with an increasing phase followed by a decreasing phase. Ang II-induced autophagic increases were potentiated by inhibition of PI3KC1 with LY294002, but were impaired by inhibition of PI3KC3 with 3-methyladenine (3-MA). In addition, blockade of PI3KC1 significantly attenuated Ang II-induced ROS production and cardiomyocyte hypertrophy. In contrast, blockade of PI3KC3 potentiated Ang II-induced ROS production and cardiac hypertrophy. Moreover, blockade of PI3KC1 by overexpression of dominant negative p85 subunit of PI3KC1 significantly attenuated Ang II-induced cardiac hypertrophy in normotensive rats. Taken together, these results demonstrate that both PI3KC1 and PI3KC3 are involved in Ang II-induced cardiac hypertrophy by different mechanisms. Activation of PI3KC1 impairs autophagy activity, leading to accumulation of mitochondrial ROS, and, hence, cardiac hypertrophy. In contrast, activation of PI3KC3 improves autophagy activity, thereby reducing mitochondrial ROS and leads to a protective effect on Ang II-induced cardiac hypertrophy.

The Therapeutic Potential of Quercetin in Parkinson's Disease: Insights into its Molecular and Cellular Regulation

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder characterized by the progressive death of dopaminergic neurons in the substantia nigra pars compacta (SNc). PD is a multifactorial disorder, with several different factors being suggested to play a synergistic pathophysiological role, including oxidative stress, autophagy, underlying pro-inflammatory events and neurotransmitters abnormalities. Overall, PD can be viewed as the product of a complex interaction of environmental factors acting on a given genetic background. The importance of this subject has gained more attention to discover novel therapies to prevent as well as treat PD. According to previous research, drugs used to treat PD have indicated significant limitations. Therefore, the role of flavonoids has been extensively studied in PD treatment. Quercetin, a plant flavonol from the flavonoid group, has been considered as a supplemental therapy for PD. Quercetin has pharmacological functions in PD by controlling different molecular pathways. Although few studies intended to evaluate the basis for the use of quercetin in the context of PD have been conducted so far, at present, there is very little evidence available addressing the underlying mechanisms of action. Various principal aspects of these treatment procedures remain unknown. Here, currently existing knowledge supporting the use of quercetin for the clinical management of PD has been reviewed.

Advanced glycation end products and their adverse effects: The role of autophagy

The critical roles played by advanced glycation endproducts (AGEs) accumulation in diabetes and diabetic complications have gained intense recognition. AGEs interfere with the normal functioning of almost every organ with multiple actions like apoptosis, inflammation, protein dysfunction, mitochondrial dysfunction, and oxidative stress. However, the development of a potential treatment strategy is yet to be established. Autophagy is an evolutionarily conserved cellular process that maintains cellular homeostasis with the degradation and recycling systems. AGEs can activate autophagy signaling, which could be targeted as a therapeutic strategy against AGEs induced problems. In this review, we have provided an overview of the adverse effects of AGEs, and we put forth the notion that autophagy could be a promising targetable strategy against AGEs.

NRF2-Related Epigenetic Modifications in Cardiac and Vascular Complications of Diabetes Mellitus

Diabetes mellitus (DM) is a highly prevalent chronic disease that is accompanied with serious complications, especially cardiac and vascular complications. Thus, there is an urgent need to identify new strategies to treat diabetic cardiac and vascular complications. Nuclear factor erythroid 2-related factor 2 (NRF2) has been verified as a crucial target for the prevention and treatment of diabetic complications. The function of NRF2 in the treatment of diabetic complications has been widely reported, but the role of NRF2-related epigenetic modifications remains unclear. The purpose of this review is to summarize the recent advances in targeting NRF2-related epigenetic modifications in the treatment of cardiac and vascular complications associated with DM. We also discuss agonists that could potentially regulate NRF2-associated epigenetic mechanisms. This review provides a better understanding of strategies to target NRF2 to protect against DM-related cardiac and vascular complications.

Perspectives on signaling for biological- and processed food-related advanced glycation end-products and its role in cancer progression

Receptor for advanced glycation end-products (RAGE) is a multifunctional receptor binds a broad spectrum of ligands and mediates responses to cell damage and stress conditions. It also activates programs leading to acute and chronic inflammation and implicated in several pathological diseases, including cancer. In this review, we presented the non-enzymatic reaction of reducing sugar with the amino groups of proteins, lipids, and nucleic acids. This reaction initiates a complex series of rearrangements and dehydrations, and then produces a class of irreversibly cross-linked heterogeneous fluorescent moieties, termed advanced glycation end products (AGEs). There is a growing body of evidence that interaction of processes food-related AGEs with a cell surface receptor RAGE brings out the generation of oxidative stress and subsequently evokes proliferative, angiogenic and inflammatory reactions, thereby being involved in the development and progression of various types of cancers. This review is an insightful assessment of molecular mechanisms through which RAGE signaling contributes to the enhancement and survival of the tumorigenic cell. Here we summarize the procurement of individual ligands of RAGE like amphoterin, calcium-binding proteins, and resultant mediation of RAGE signaling pathway, which partially can elucidate the elevated risk of several cancers. Besides, we summarize many factors or conditions including APE1 (apurinic/apyrimidinic endonuclease 1), retinol mutations, retinoblastoma (Rb), proteinase 3 (PR3) hypoxia and so on through which RAGE signaling presents an establishment of cancerous environment. Additionally, we also reviewed some recent findings that give shreds of evidence for presenting the role of RAGE and its ligands in the advanced stage of cancers.

FKBPL is associated with metabolic parameters and is a novel determinant of cardiovascular disease

Type 2 diabetes (T2D) is associated with increased risk of cardiovascular disease (CVD). As disturbed angiogenesis and endothelial dysfunction are strongly implicated in T2D and CVD, we aimed to investigate the association between a novel anti-angiogenic protein, FK506-binding protein like (FKBPL), and these diseases. Plasma FKBPL was quantified by ELISA cross-sectionally in 353 adults, consisting of 234 T2D and 119 non-diabetic subjects with/without CVD, matched for age, BMI and gender. FKBPL levels were higher in T2D (adjusted mean: 2.03 ng/ml ± 0.90 SD) vs. non-diabetic subjects (adjusted mean: 1.79 ng/ml ± 0.89 SD, p = 0.02), but only after adjustment for CVD status. In T2D, FKBPL was negatively correlated with fasting blood glucose, HbA1c and diastolic blood pressure (DBP), and positively correlated with age, known diabetes duration, waist/hip ratio, urinary albumin/creatinine ratio (ACR) and fasting C-peptide. FKBPL plasma concentrations were increased in the presence of CVD, but only in the non-diabetic group (CVD: 2.02 ng/ml ± 0.75 SD vs. no CVD: 1.68 ng/ml ± 0.79 SD, p = 0.02). In non-diabetic subjects, FKBPL was positively correlated with an established biomarker for CVD, B-type Natriuretic Peptide (BNP), and echocardiographic parameters of diastolic dysfunction. FKBPL was a determinant of CVD in the non-diabetic group in addition to age, gender, total-cholesterol and systolic blood pressure (SBP). FKBPL may be a useful anti-angiogenic biomarker in CVD in the absence of diabetes and could represent a novel CVD mechanism.

Autophagy participates in the protection role of 1,25-dihydroxyvitamin D3 in acute myocardial infarction via PI3K/AKT/mTOR pathway

Vitamin D deficiency is associated with acute myocardial infarction (AMI); thus we aimed to explore improvement effects of 1,25-dihydroxyvitamin D3 (VD3) on the AMI and its potential mechanism. AMI models were constructed using male C57/BL6J mice and randomly treated with normal saline or VD3, using sham rats as control. Heart functions, myocardial damage, apoptosis, and inflammation were evaluated. Cardiomyocytes isolated from 3-day-old suckling mice were used for in vitro verification. After VD3 treatment, AMI-induced cardiac dysfunction was reversed with better cardiac function parameters. VD3 treatment reduced inflammatory cell infiltration and myocardial infarction area accompanied by the reduction of inflammatory factors and myocardial infarction markers compared with the AMI group. VD3 treatment obviously alleviated AMI-induced myocardial apoptosis, along with Bcl-2 upregulation and downregulation of caspase-3, caspase-9, and Bax. Both in vivo and in vitro experiments revealed that VD3 enhanced the expression of LC3II and Beclin-1 and decreased soluble p62. Furthermore, VD3 enhanced the AMI-caused inhibition of PI3K, p-AKT, and p-mTOR expression, which was conversely reversed by the addition of 3-methyladenine in vitro. The study highlights the improvement effects of VD3 on cardiac functions. We proposed a potential mechanism that VD3 protects against myocardial damage, inflammation, and apoptosis by promoting autophagy through PI3K/AKT/mTOR pathway.

NO66 overexpression rescues ethanol-induced cell apoptosis in human AC16 cardiomyocytes by suppressing PTEN and activating the PI3K/Akt signaling

Previously, Nucleolar protein 66 (NO66) was reported to be closely associated with alcohol exposure-induced injury. However, the role of NO66 in alcohol-induced cytotoxicity remains unclear. In this study, we explored the potential effect and mechanism of NO66 on ethanol-induced apoptosis in human AC16 cardiomyocytes. The AC16 cell lines with NO66 and phosphatase and tensin homolog (PTEN) overexpression were constructed. Cell counting kit-8 (CCK-8), lactate dehydrogenase (LDH) assay, Annexin V-FITC/PI staining, and flow cytometry were used to evaluate the cell viability, membrane damage, and apoptosis, respectively. Quantitative real-time PCR (qRT-PCR) and western blot analysis were applied to measure mRNA and protein expression. The results showed that acute ethanol exposure markedly augmented cytotoxicity and reduced NO66 level in AC16 cardiomyocytes. Overexpression of NO66 partially reversed ethanol-induced apoptosis. NO66 upregulation reversed the decrease in phosphorylation of protein kinase B (Akt) and B-cell lymphoma-2/Bcl-2-associated x (Bcl-2/Bax) ratio and the increase in PTEN, p53, and caspase-3 activity induced by ethanol treatment. Meanwhile, the application of PI3K inhibitor (LY294002) and PTEN overexpression attenuated the inhibition efficiency of NO66 on cell apoptosis. In addition, PTEN overexpression weakened the effect of NO66 on PI3K/Akt activation, without affecting the level of NO66. Our data suggested that NO66 overexpression might play an anti-apoptotic role in ethanol-induced cell injury via reducing PTEN and upregulating the PI3K/Akt pathway.

S100A8 and S100A9 promote endothelial cell activation through the RAGE‑mediated mammalian target of rapamycin complex 2 pathway

S100 calcium binding protein A8 (S100A8) and A9 (S100A9) belong to the S100 family of calcium-binding proteins and have important roles in inflammation. They increase endothelial cell proliferation, thereby affecting inflammation, angiogenesis and tumorigenesis. However, the mechanism of action of S100A8/9 in endothelial cells needs further study. Therefore, the present study sought to investigate the effects of S100A8/9 on the proliferation and angiogenesis of human umbilical vein endothelial cells (HUVECs) and their mechanism of action. The viability of HUVECs was determined through a Cell Counting Kit-8 assay. The effect of S100A8/9 on the proliferation of HUVECs was detected by flow cytometry. Migration was evaluated by a Transwell migration assay. Apoptosis was evaluated by Annexin V-FITC and PI staining via flow cytometry. Western blot analysis and reverse transcription-quantitative polymerase chain reaction assays were performed to evaluate the activation of the phosphatidylinositol 3-phosphate kinase (PI3K)/Akt/mTOR pathway and mTOR complex 2 (mTORC2). We previously confirmed that S100A8/9 were consistently overexpressed at 1 and 7 days post-surgery in a rabbit vein graft model, which is the period when apoptosis changes to proliferation in neointimal hyperplasia. In the present study, proliferation, viability and migration were increased after treating HUVECs with S100A8/9. S100A8/9 stimulated the PI3K/Akt/mTOR pathway and mTORC2, which was significantly suppressed by a receptor for advanced glycation end products (RAGE)-blocking antibody. Furthermore, depleting expression of RAGE or mTORC2 protein components (rapamycin-insensitive companion of mTOR) by small interfering RNA was found to reduce the cell viability, migration and angiogenesis of S100A8/9-treated HUVECs. The development of neointimal hyperplasia is a complex process initiated by damage to endothelial cells. In conclusion, S100A8/9 has an important role in intimal hyperplasia by promoting cell growth and angiogenesis via RAGE signaling and activation of mTORC2.

AGE-RAGE synergy influences programmed cell death signaling to promote cancer

Advanced glycation end products (AGEs) are formed as a result of non-enzymatic reaction between the free reducing sugars and proteins, lipids, or nucleic acids. AGEs are predominantly synthesized during chronic hyperglycemic conditions or aging. AGEs interact with their receptor RAGE and activate various sets of genes and proteins of the signal transduction pathway. Accumulation of AGEs and upregulated expression of RAGE is associated with various pathological conditions including diabetes, cardiovascular diseases, neurodegenerative disorders, and cancer. The role of AGE-RAGE signaling has been demonstrated in the progression of various types of cancer and other pathological disorders. The expression of RAGE increases manifold during cancer progression. The activation of AGE-RAGE signaling also perturbs the cellular redox balance and modulates various cell death pathways. The programmed cell death signaling often altered during the progression of malignancies. The cellular reprogramming of AGE-RAGE signaling with cell death machinery during tumorigenesis is interesting to understand the complex signaling mechanism of cancer cells. The present review focus on multiple molecular paradigms relevant to cell death particularly Apoptosis, Autophagy, and Necroptosis that are considerably influenced by the AGE-RAGE signaling in the cancer cells. Furthermore, the review also attempts to shed light on the provenience of AGE-RAGE signaling on oxidative stress and consequences of cell survival mechanism of cancer cells.

Fusarium infection alters the m6A-modified transcript landscape in the cornea

N6-methyladenosine (m⁶A) is the most common post-transcriptional modification of RNA in eukaryotes that regulates the post-transcriptional expression level of genes without changing the base sequence. The role of m⁶A in fungal keratitis has not yet been elucidated. Here, we aimed to identify m⁶A modification changes and their potential roles in fungal keratitis. The murine model of fungal keratitis was established by inoculating mice with Fusarium solani (F. solani). The overall m⁶A level was detected via an m⁶A RNA methylation assay kit. The expression levels of key m⁶A modification-related genes were estimated by quantitative real-time polymerase chain reaction (PCR). The expression and localization of METTL (methyltransferase like)3, the key component of the m⁶A methyltransferase complex, was determined by immunostaining and Western blotting (WB). Immunoprecipitation methylation microarray was used to describe the changes in m⁶A modification in F. solani-infected corneal tissue. The overall m⁶A level in corneal tissue on the 5th day in the F. solani-treated group was upregulated compared with that in the control group. The demethylase levels were unaltered, but the level of the methylase METTL3 was increased significantly after fungal infection. Additionally, differences were found in m⁶A modifications in 1137 mRNAs, of which 780 were hypermethylated and 357 were hypomethylated. To the best of our knowledge, the present work is the first investigation on the m⁶A modification profiles in experimental fungal keratitis, and it may provide a potential therapeutic target.

YBX1 mediates autophagy by targeting p110β and decreasing the sensitivity to cisplatin in NSCLC

Y-box binding protein 1 (YBX1) is involved in the development of multiple types of tumors. However, the relationship between YBX1 and autophagy in non-small cell lung cancer (NSCLC) remains unclear. In this study, we analyzed the expression and clinical significance of YBX1 and markers of autophagy (LC3I/II) in NSCLC and examined their roles in regulating sensitivity to cisplatin in NSCLC. The retrospective analysis of patients with NSCLC indicated that YBX1 was positively correlated with autophagy. Increased levels of YBX1 or autophagy also observed in NSCLC cells compared with those in 16HBE cells. Compared to the controls, the knockdown of YBX1 expression suppressed autophagy, increased drug sensitivity and promoted apoptosis in response to cisplatin in NSCLC cells by targeting the p110β promoter and inhibiting p110β/Vps34/beclin1 signaling pathways. We also demonstrated in an in vivo study that the overexpressed YBX1 effectively increased NSCLC growth and progression and decreased the sensitivity to cisplatin by inducing autophagy in a xenograft tumor model, and these effects were concomitant with the increasing of p110β and beclin1 expression. Collectively, these results show that YBX1 plays an essential role in autophagy in NSCLC.

Molecular mechanisms of methylglyoxal-induced aortic endothelial dysfunction in human vascular endothelial cells

Methylglyoxal (MGO)-induced cellular apoptosis, oxidative stress, inflammation, and AGE formation are specific events that induce vascular endothelial cell (EC) toxicity in endothelial dysfunction (ED). MGO accumulates quickly in various tissues and plays a prominent role in the pathogeneses of several diabetic complications. Unbalanced angiogenesis is a gateway to the development of diabetic complications. EC apoptosis and autophagy work together to regulate angiogenesis by interacting with different angiogenic factors. In addition to understanding the deep mechanism regarding MGO-dependent autophagy/apoptosis may provide new therapeutic applications to treat diabetes and diabetic complications. Therefore, the present study aimed to investigate the regulatory effects of MGO-induced autophagy and apoptosis on angiogenesis in HAoEC and to elucidate the molecular mechanisms to discover new target base therapy for diabetes and diabetic complications. In MGO-stimulated HAoEC, protein expression was identified using a western blot, autophagosomes were observed by bio-transmission electron microscopy (TEM), and cell autophagic vacuoles and flux were measured using a confocal microscope. We found that MGO significantly induced autophagy, declined the pro-angiogenic effect, decreased proliferation, migration, and formation of tube-like structures, and increased autophagic vacuoles, flux and autophagosomes in the HAoEC in a dose-dependent manner. We observed that MGO-induced autophagic cell death and inhibited the ROS-mediated Akt/mTOR signaling pathway. MGO also triggered apoptosis by elevating the cleaved caspase-3 to Bax/Bcl-2 ratio and through activation of the ROS-mediated MAPKs (p-JNK, p-p38, and p-ERK) signaling pathway. Collectively, these findings suggest that autophagy and apoptosis inhibit angiogenesis via the ROS-mediated Akt/mTOR and MAPKs signaling pathways, respectively, when HAoEC are treated with MGO.

Beta carotene protects H9c2 cardiomyocytes from advanced glycation end product-induced endoplasmic reticulum stress, apoptosis, and autophagy via the PI3K/Akt/mTOR signaling pathway

Background

Diabetic cardiomyopathy (DCM), which is associated with many pathological processes, commonly occurs when advanced glycation end products (AGEs) are present. β-carotene (BC) is a well-known vitamin A precursor that is found in many fruits and vegetables. BC can reduce the risk of cancer and cardiovascular disease. This study aimed to investigate the effect of BC on AGE-induced myocardial injury in vitro.

Methods

Cell viability test was used to select 40 µM concentrations of BC to treat AGE-induced H2c9 cells. The cell apoptosis was detected by flow cytometry. Western blotting was used to measure the protein expression levels of Bcl-2-associated X protein (Bax), B-cell lymphoma-2 (Bcl-2), cleaved caspase-3, activating transcription factor 4 (ATF4), glucose-regulated protein 78 (GRP78), CCAAT/enhancer-binding protein homologous protein (CHOP), beclin 1, p62,microtubule-associated protein 1 light chain 3 (LC3), phosphorylated PI3K (p-PI3K), phosphorylated Akt (p-AKT), and phosphorylated mTOR (p-mTOR). Enzyme-linked immunosorbent assay (ELISA) was performed to measure the levels of lactate dehydrogenase (LDH) and cardiac troponin-1 (cTn-I). Reactive oxygen species (ROS) was detected by flow cytometry. The levels of malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) were used to determine MDA kits, SOD assay kit and GSH-Px kit, respectively.

Results

BC significantly inhibited AGE-induced cell death and apoptosis in H9c2 cells. BC had a suppressive effect on intracellular ROS production and antioxidative enzyme reduction. Moreover, BC decreased hyperactive endoplasmic reticulum (ER) stress and autophagy in H9c2 cells. Furthermore, BC exerted a cardioprotective effect in AGE-induced H9c2 cells via the activation of the PI3K/Akt/mTOR signaling pathway.

Conclusions

BC exhibited a cardioprotective effect AGE-induced apoptosis. Our study provides a foundation for further study into the potential value of BC for treating DCM or other heart diseases.

Effect of Dipeptidyl-Peptidase 4 Inhibitors on Circulating Oxidative Stress Biomarkers in Patients with Type 2 Diabetes Mellitus

Pre-clinical studies suggested potential cardiovascular benefits of dipeptidyl peptidase-4 inhibitors (DPP4i), however, clinical trials showed neither beneficial nor detrimental effects in patients with type 2 diabetes mellitus (T2DM). We examined the effects of DPP4i on several circulating oxidative stress markers in a cohort of 32 T2DM patients (21 males and 11 post-menopausal females), who were already on routine antidiabetic treatment. Propensity score matching was used to adjust demographic and clinical characteristics between patients who received and who did not receive DPP4i. Whole-blood reactive oxygen species (ROS), plasma advanced glycation end products (AGEs), advanced oxidation protein products (AOPP), carbonyl residues, as well as ferric reducing ability of plasma (FRAP) and leukocyte DNA oxidative damage (Fpg sites), were evaluated. With the exception of Fpg sites, that showed a borderline increase in DPP4i users compared to non-users (p = 0.0507), none of the biomarkers measured was affected by DPP4i treatment. An inverse correlation between estimated glomerular filtration rate and AGEs (p < 0.0001) and Fpg sites (p < 0.05) was also observed. This study does not show any major effect of DPP4i on oxidative stress, assessed by several circulating biomarkers of oxidative damage, in propensity score-matched cohorts of T2DM patients.

Polydatin protects H9c2 cells from hypoxia-induced injury via up-regulating long non-coding RNA DGCR5

Polydatin (PD), a monocrystalline polyphenolic drug mainly found in the roots of Polygonum cuspidatum, has various pharmacological activities. Long non-coding RNAs (lncRNA) DiGeorge syndrome critical region gene 5 (DGCR5) was found to participate in the suppression of multiple cancers. Here, we proposed to study the effect of PD on myocardial infarction (MI) by inducing DGCR5. CCK-8 assay was performed to detect the viability of H9c2 cells. Flow cytometry was utilized to test apoptosis of H9c2 cells. These results determined the optimal concentration and effect time of hypoxia as well as PD. Si-DGCR5 was transfected into cells and the expression level was determined by qRT-PCR. Western blot was utilized to evaluate the expression of apoptosis-related proteins, Bcl-2, Bax, and cleaved-caspase-3, as well as autophagy-associated proteins including Beclin-1, p62, and LC3-II/LC3-I. As a result, PD efficiently attenuated hypoxia-induced apoptosis and autophagy in H9c2 cells. The expression of DGCR5 was down-regulated by hypoxia and up-regulated by PD. Besides, knocking-down the expression of DGCR5 inhibited the protection of PD in H9c2 cells. In addition, PD up-regulated the accumulation of DGCR5, DGCR5 decreased the expression of Bcl-2 and p62, raised the expression of Bax and cleaved-caspase-3, and the proportion of LC3-II/LC3-I. PD stimulated the PI3K/AKT/mTOR and MEK/ERK signaling pathways via up-regulating the expression of DGCR5. Our data demonstrated that PD reduced cell apoptosis and autophagy induced by hypoxia in cardiomyocytes. Moreover, PD activated PI3K/AKT/mTOR and MEK/ERK signaling pathways by up-regulating the expression of DGCR5.

Cigarette smoke triggers inflammation mediated by autophagy in BEAS-2B cells

Cigarette smoking, as an individual consumption habit, is associated with a variety of related diseases. Exposure of cigarette smoke was reported to induce autophagy and inflammation in experimental animals and humans. However, the toxicity mechanism of cigarette smoke in organisms has not been entirely investigated. In this present study, we studied the role of autophagy played in the inflammation caused by cigarette smoke in human bronchial epithelial cells (BEAS-2B), as well as the role of the phosphatidylinositol 3-kinase (PI3K) signaling pathway and the mitogen-activated protein kinase (MAPK) signaling pathways underlying autophagy and inflammation. We found that cigarette smoke induced autophagy and inflammation in BEAS-2B, and the blockage of autophagy significantly reduced the release levels of IL-1β, IL-6 and IL-8 in BEAS-2B exposed to cigarette smoke for 24 h. Cigarette smoke downregulated the activity of PI3K/Akt/mTOR pathway and elevated the activity of MAPK pathways. Pretreatment of autophagic inhibitor could inhibit autophagy and the activity of JNK and p38 pathways. These results suggested that cigarette smoke-induced autophagy triggered inflammation through the activation of JNK and p38 pathways, which might contribute to understanding the adverse outcome pathways induced by cigarette smoke exposure and provide the information about the risk assessment of tobacco products.

Co-enzyme Q10 protects primary chicken myocardial cells from heat stress by upregulating autophagy and suppressing the PI3K/AKT/mTOR pathway

In this study, we investigated the function of co-enzyme Q10 (Q10) in autophagy of primary chicken myocardial cells during heat stress. Cells were treated with Q10 (1 μΜ, 10 μΜ, and 20 μM) before exposure to heat stress. Pretreatment of chicken myocardial cells with Q10 suppressed the decline in cell viability during heat stress and suppressed the increase in apoptosis during heat stress. Treatment with 20 μM Q10 upregulated autophagy-associated genes during heat stress. The expression of LC3-II was highest in cells treated with 20 μM Q10. Pretreatment with Q10 decreased reactive oxygen species (ROS) levels during heat stress. The number of autophagosomes was significantly increased by 20 μM Q10 treatment, as demonstrated by electron microscopy or monodansylcadaverine (MDC) fluorescence. SQSTM1 accumulation was diminished by Q10 treatment during heat stress, and the number of LC3II puncta was increased. Treatment with 20 μM Q10 also decreased the activation of the PI3K/Akt/mTOR pathway. Our results showed that co-enzyme Q10 can protect primary chicken myocardial cells by upregulating autophagy and suppressing the PI3K/Akt/mTOR pathway during heat stress.

Transplantation of Human Urine-Derived Stem Cells Ameliorates Erectile Function and Cavernosal Endothelial Function by Promoting Autophagy of Corpus Cavernosal Endothelial Cells in Diabetic Erectile Dysfunction Rats

Aims

Cavernosal endothelial dysfunction is one of the factors in developing diabetic erectile dysfunction (DED), but the mechanism of cavernosal endothelial dysfunction is unclear. The present study is aimed at determining the contribution of autophagy in cavernosal endothelial dysfunction of DED rats and explaining the therapeutic effect of urine-derived stem cells (USCs).

Methods

After rat corpus cavernosal vascular endothelial cells (CCECs) were isolated and cultured in vitro, CCECs were treated with advanced glycation end products (AGEs) to mimic the diabetic situation. Autophagy flux, proliferation, and apoptosis of CCECs were determined by mRFP-GFP-LC3 adenovirus infection combined with fluorescence observation and western blot analysis. USCs were isolated from the urine of six healthy male donors, and coculture systems of USCs and CCECs were developed to assess the protective effect of USCs for CCECs in vitro. The contribution of autophagy to the cellular damage in CCECs was evaluated by the autophagic inhibitor, 3-methyladenine (3-MA). Then, DED rats were induced by streptozotocin (50 mg/kg) and screened by apomorphine test (100 μg/kg). In DED rats, USCs or PBS as vehicle was administrated by intracavernous injection (n = 15 per group), and another 15 normal rats served as normal controls. Four weeks after injection, erectile function was evaluated by measuring the intracavernosal pressure (ICP) and mean arterial pressure (MAP). Cavernosal endothelial function and autophagic activity were examined by western blot, immunofluorescence, and transmission electron microscopy.

Results

In vitro, AGE-treated CCECs displayed fewer LC3 puncta formation and expressed less LC3-II, Beclin1, and PCNA but expressed more p62 and cleaved-caspase3 than controls (p < 0.05). Coculture of USCs with CCECs demonstrated that USCs were able to protect CCECs from AGE-induced autophagic dysfunction and cellular damage, which could be abolished by 3-MA (p < 0.05). DED rats showed lower ratio of ICP/MAP, reduced expression of endothelial markers, and fewer autophagic vacuoles in the cavernosal endothelium when compared with normal rats (p < 0.05). Intracavernous injection of USCs improved erectile function and cavernosal endothelial function of DED rats (p < 0.05). Most importantly, our data showed that the repaired erectile function and cavernosal endothelial function were the result of restored autophagic activity of the cavernosal endothelium in DED rats (p < 0.05).

Conclusions

Impaired autophagy is involved in the cavernosal endothelial dysfunction and erectile dysfunction of DED rats. Intracavernous injection of USCs upregulates autophagic activity in the cavernosal endothelium, contributing to ameliorating cavernosal endothelial dysfunction and finally improving the erectile dysfunction induced by diabetes.

Hyperglycemia-Induced Aberrant Cell Proliferation; A Metabolic Challenge Mediated by Protein O-GlcNAc Modification

Chronic hyperglycemia has been associated with an increased prevalence of pathological conditions including cardiovascular disease, cancer, or various disorders of the immune system. In some cases, these associations may be traced back to a common underlying cause, but more often, hyperglycemia and the disturbance in metabolic balance directly facilitate pathological changes in the regular cellular functions. One such cellular function crucial for every living organism is cell cycle regulation/mitotic activity. Although metabolic challenges have long been recognized to influence cell proliferation, the direct impact of diabetes on cell cycle regulatory elements is a relatively uncharted territory. Among other "nutrient sensing" mechanisms, protein O-linked β-N-acetylglucosamine (O-GlcNAc) modification emerged in recent years as a major contributor to the deleterious effects of hyperglycemia. An increasing amount of evidence suggest that O-GlcNAc may significantly influence the cell cycle and cellular proliferation. In our present review, we summarize the current data available on the direct impact of metabolic changes caused by hyperglycemia in pathological conditions associated with cell cycle disorders. We also review published experimental evidence supporting the hypothesis that O-GlcNAc modification may be one of the missing links between metabolic regulation and cellular proliferation.

Accumulation of advanced glycation end products potentiate human retinal capillary endothelial cells mediated diabetic retinopathy

The major ophthalmic complication in patients with diabetes is diabetic retinopathy (DR), which is one of the major eye diseases that causes blindness. It is well established that the occurrence and duration of DR is positively correlated with duration of diabetes. Advanced glycation end product (AGE) accumulation in patients with diabetes is one factor that leads to the development of DR. However, the underlying mechanisms remain unclear. In the present study, the role of phosphoinositide 3‑kinase/protein kinase B (Akt) signaling in AGE‑induced DR development was investigated. An in vitro experimental system was used to study the effects of AGEs on human retinal capillary endothelial cells (HRCECs) and Müller cells. Flow cytometry, MTT, western blotting and BrdU incorporation assays were performed. Reverse transcription‑quantitative polymerase chain reaction was used to measure the expression of angiogenesis‑associated genes. Functional assays of angiogenesis, including HRCEC invasion and tube formation assays. It was demonstrated that the expression of receptor for AGEs was upregulated in HRCECs and Müller cells following treatment with AGEs. AGE treatment did not affect Müller cell viability, but enhanced HRCEC viability. Akt inhibition increased cell apoptosis and death in HRCECs. AGE treatment upregulated the expression of pro‑angiogenic genes, which was suppressed by Akt inhibitor treatment. In addition, Akt inhibitor treatment suppressed HRCEC invasion and tube formation ability. The present study suggested that Akt‑mediated signaling may serve critical roles in the development of DR due to the accumulation of AGEs. Akt may be a potential therapeutic target in DR.

IL-17 and CD40 ligand synergistically stimulate the chronicity of diabetic nephropathy

Background

Early stages of diabetic nephropathy (DN) are characterized by an influx of inflammatory cells. Interactions between infiltrating T cells and podocytes may play an important role in the ongoing inflammatory response and remodelling. The aim of this study was to explore the role of IL-17 and CD40 ligand (CD40L) in DN.

Methods

The study design involved a case series. Kidney biopsy samples of 69 patients with type 2 diabetes were assessed for the presence of CD4+ IL-17+ T cells. The number of CD4+ IL-17+ T cells were counted and correlated with clinical and laboratory findings. Additionally, advanced glycation end-products (AGEs) were added to cultured podocytes to imitate diabetic conditions and thus to elucidate the role of CD4+ IL-17+ T cells in renal sclerosis.

Results

CD80 expression was detected in early phases of DN but was absent during diffused glomerurosclerosis in DN kidney specimens. In DN samples, CD40 expression was not only observed in most of the infiltrating cells, but also increased in podocytes and tubular epithelial cells. CD40L is locally expressed on infiltrating cells. CD4+ IL-17+ T cells were found in DN, and the number of CD4+ IL-17+ T cells was positively correlated with the deterioration in glomerular filtration rate (GFR). IL-17A was the key cytokine produced by CD4+ IL-17+ T cells. IL-17A levels were elevated in DN renal tissue and were correlated with declining GFR. IL-17 and CD40L synergistically enhanced IL-6, monocyte chemoattractant protein-1 (MCP-1), regulated on activation, normal T cell expressed and secreted (RANTES), transforming growth factor beta 1 (TGF-β1) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) production in vitro. AGEs induced podocyte activation with increasing expression of IL-17A, CD40 and TGF-β1 in vitro. Blockade with an anti-IL-17 monoclonal antibody reduced the expression of CD40 and TGF-β1, but increased the viability of cultured podocytes.

Conclusions

IL-17 and CD40L synergistically mediate the inflammatory response and remodelling associated with tissue injury and glomerular sclerosis in DN.