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BACKGROUND: Dysfunction of the glymphatic system in the brain in different stages of altered glucose metabolism and its influencing factors are not well characterized. AIM: To investigate the function of the glymphatic system and its clinical correlates in patients with different glucose metabolism states, the present study employed diffusion tensor imaging along the perivascular space (DTI-ALPS) index. METHODS: Sample size was calculated using the pwr package in R software. This cross-sectional study enrolled 22 patients with normal glucose metabolism (NGM), 20 patients with prediabetes, and 22 patients with type 2 diabetes mellitus (T2DM). A 3.0T magnetic resonance imaging was used to evaluate the function of the glymphatic system. The mini-mental state examination (MMSE) was used to assess general cognitive function. The DTI-ALPS index of bilateral basal ganglia and the mean DTI-ALPS index was calculated. Further, the correlation between DTI-ALPS and clinical features was assessed. RESULTS: The left-side, right-side, and mean DTI-ALPS index in the T2DM group were significantly lower than that in the NGM group. The right-side DTI-ALPS and mean DTI-ALPS index in the T2DM group were significantly lower than those in the prediabetes group. DTI-ALPS index lateralization was not observed. The MMSE score in the T2DM group was significantly lower than that in the NGM and prediabetes group. After controlling for sex, the left-side DTI-ALPS and mean DTI-ALPS index in the prediabetes group were positively correlated with 2-hour postprandial blood glucose level; the left-side DTI-ALPS index was negatively correlated with total cholesterol and low-density lipoprotein level. The right-side DTI-ALPS and mean DTI-ALPS index were negatively correlated with the glycosylated hemoglobin level and waist-to-hip ratio in the prediabetes group. The left-side, right-side, and mean DTI-ALPS index in the T2DM group were positively correlated with height. The left-side and mean DTI-ALPS index in the T2DM group were negatively correlated with high-density lipoprotein levels. CONCLUSION: Cerebral glymphatic system dysfunction may mainly occur in the T2DM stage. Various clinical variables were found to affect the DTI-ALPS index in different glucose metabolism states. This study enhances our understanding of the pathophysiology of diabetic brain damage and provides some potential biological evidence for its early diagnosis.
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Increasing evidences implicate vital role of neuronal damage in the development of hepatic encephalopathy (HE). Neurofilament light chain (NfL) is the main frame component of neurons and is closely related to axonal radial growth and neuronal structural stability. We hypothesized that NfL as a biomarker of axonal injury may contribute to early diagnosis of HE. This study recruited 101 patients with liver cirrhosis, 10 healthy individuals, and 7 patients with Parkinson's disease. Minimal hepatic encephalopathy (MHE) was diagnosed using psychometric hepatic encephalopathy score. Serum NfL levels were measured by the electrochemiluminescence immunoassay. Serum NfL levels in cirrhotic patients with MHE were significantly higher than cirrhotic patients without MHE, and increased accordingly with the aggravation of HE. Serum NfL levels were associated with psychometric hepatic encephalopathy score, Child-Pugh score, model for end-stage liver disease score, and days of hospitalization. Additionally, serum NfL was an independent predictor of MHE (odds ratio of 1.020 (95% CI 1.005-1.034); P = 0.007). The discriminative abilities of serum NfL were high for identifying MHE (AUC of 0.8134 (95% CI 0.7130-0.9219); P Ë 0.001) and OHE (AUC of 0.8852 (95% CI 0.8117-0.9587); P Ë 0.001). Elevated serum NfL levels correlated with the presence of MHE and associated with the severity of HE, are expected to be a biomarker in patients with cirrhosis. Our study suggested that neuronal damage may play a critical role in the development of HE.
Subject(s)
Biomarkers , Hepatic Encephalopathy , Liver Cirrhosis , Neurofilament Proteins , Humans , Hepatic Encephalopathy/blood , Hepatic Encephalopathy/diagnosis , Male , Female , Neurofilament Proteins/blood , Middle Aged , Liver Cirrhosis/blood , Liver Cirrhosis/complications , Biomarkers/blood , Aged , AdultABSTRACT
Soil heavy metal contamination has become a global environmental issue, which threaten soil quality, food security and human health. Symphytum officinale L. have exhibited high tolerance and restoration capacity to heavy metals (HMs) stress. However, little is known about the mechanisms of HMs in S. officinale. In this study, transcriptomic and physiological changes of S. officinale response to different HMs (Pb, Cd and Zn) were analyzed and investigated the key genes and pathways involved in HMs uptake patterns. The results showed that phenotypic effects are not significant, and antioxidant enzyme activities were all upregulated. Transcriptome analysis indicated that 1247 differential genes were up-regulated, and 1963 differential genes were down-regulated under Cd stress, while 3752 differential genes were up-regulated, and 7197 differential genes were down-regulated under Pb stress; and 527 differential genes were up-regulated; and 722 differential genes were down-regulated under Zn stress. Based on their expression, we preliminarily speculate that different HMs resistance of S. officinale may be regulated by the differential expression of key genes. These results provide a theoretical basis for determining the exact expression of genes in plants under different heavy metal stress, the processes involved molecular pathways, and how they can be efficiently utilized to improve plant tolerance to toxic metals and improve phytoremediation efficiency.
Subject(s)
Metals, Heavy , Soil Pollutants , Transcriptome , Metals, Heavy/toxicity , Soil Pollutants/toxicity , Transcriptome/drug effects , Stress, Physiological/drug effects , Stress, Physiological/genetics , Lead/toxicity , Gene Expression Regulation, Plant/drug effects , Cadmium/toxicity , Gene Expression Profiling , Biodegradation, Environmental , Zinc/toxicityABSTRACT
Nano scale topography scaffold is more bioactive and biomimetic than smooth fiber topographies. Tendon stem cells (TSCs) play important roles in the tendinogenesis of tendon tissue engineering, but the effects and mechanisms of nano topography on TSC behavior are still unclear. This study determined whether the morphology, proliferation, cytoskeleton, and differentiation of TSCs are affected by topography of scaffold in vitro. The porous PA56 scaffolds were prepared with different concentration ratios of glycerol as the molecular template by electrospinning. Its topological characteristics, hydrophilicity, and degradation properties varied with glycerol proportion and movement rate of the receiving plate. Porous fibers promoted the proliferation of TSCs and the number of TSCs varied with topography. Although there was no significant difference due to the small sample size, the number of pseudopodia and cell polarizability still showed differences among different topographies. The morphology of actin cytoskeleton of TSCs showed difference among cultured on porous fibers, smooth fibers, and in culture media with no fiber, suggesting the orientation growth of cells on porous fiber. Moreover, porous fibers promoted teno-lineage differentiation of TSCs by upregulating tendon-specific gene expression. These findings provide evidence that nano porous topography scaffold promotes TSC proliferation, cytoskeleton orientation, and tenogenic differentiation.
Subject(s)
Glycerol , Nanopores , Tendons , Stem Cells , Tissue Engineering , Cell Differentiation , Cell ProliferationABSTRACT
OBJECTIVE: To investigate the clinical features of transplant-associated thrombotic microangiopathy (TA-TMA) and the prognostic value of different prognostic risk models for TA-TMA. METHODS: The clinical characteristics of 32 TA-TMA patients diagnosed at the First Medical Center of the PLA General Hospital from January 2018 to February 2022 in terms of short-term prognosis and influencing factors were retrospectively analyzed. In addition, the risk population composition ratio, treatment response, and overall survival between the BATAP risk model and the TMA index model were compared, as well as the efficacy of two prognostic risk models for predicting death in patients with TA-TMA. RESULTS: Independent risk factors affecting the short-term prognosis of TA-TMA include III-IV aGVHD prior to TA-TMA diagnosis (P=0.001), renal or neurological dysfunction (P=0.006), and Hb<70 g/L (P=0.043). In the TMA index model, treatment response was worst in the high-risk group (P=0.008), while there was no significant difference in treatment response between different risk groups in the BATAP model (P=0.105). In the BATAP model, there was a statistically significant difference in the OS between the three groups of low risk, intermediate risk, and high risk (87.5% vs 61.1% vs 16.7%, χ2ï¼6.7, P=0.014). In the TMA index model, there was a statistically significant difference in the OS between the three groups of low risk, intermediate risk, and high risk (77.8% vs 45.5% vs 0.0%, χ2ï¼7.3, P=0.017). The area under the ROC curve (AUC) of the TMA index model was 0.745 (95%CI: 0.56-0.88, P<0.05), and the AUC of the BATAP model was 0.743 (95%CI: 0.56-0.88, P<0.05), indicating that both prognostic risk models have good predictive value. CONCLUSION: The short-term prognosis of TA-TMA patients might be accurately determined using both the BATAP model and the TMA index model. When predicting the efficacy of TA-TMA in different risk groups, the TMA index model may perform better than the BATAP model.
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BACKGROUND: Alterations in plasma and intestinal metabolites contribute to the pathogenesis and progression of alcohol-related liver cirrhosis (ALC). AIM: To explore the common and different metabolites in the plasma and feces of patients with ALC and evaluate their clinical implications. METHODS: According to the inclusion and exclusion criteria, 27 patients with ALC and 24 healthy controls (HCs) were selected, and plasma and feces samples were collected. Liver function, blood routine, and other indicators were detected with automatic biochemical and blood routine analyzers. Liquid chromatography-mass spectrometry was used to detect the plasma and feces metabolites of the two groups and the metabolomics of plasma and feces. Also, the correlation between metabolites and clinical features was analyzed. RESULTS: More than 300 common metabolites were identified in the plasma and feces of patients with ALC. Pathway analysis showed that these metabolites are enriched in bile acid and amino acid metabolic pathways. Compared to HCs, patients with ALC had a higher level of glycocholic acid (GCA) and taurocholic acid (TCA) in plasma and a lower level of deoxycholic acid (DCA) in the feces, while L-threonine, L-phenylalanine, and L-tyrosine increased simultaneously in plasma and feces. GCA, TCA, L-methionine, L-phenylalanine, and L-tyrosine in plasma were positively correlated with total bilirubin (TBil), prothrombin time (PT), and maddrey discriminant function score (MDF) and negatively correlated with cholinesterase (CHE) and albumin (ALB). The DCA in feces was negatively correlated with TBil, MDF, and PT and positively correlated with CHE and ALB. Moreover, we established a P/S BA ratio of plasma primary bile acid (GCA and TCA) to fecal secondary bile acid (DCA), which was relevant to TBil, PT, and MDF score. CONCLUSION: The enrichment of GCA, TCA, L-phenylalanine, L-tyrosine, and L-methionine in the plasma of patients with ALC and the reduction of DCA in feces were related to the severity of ALC. These metabolites may be used as indicators to evaluate the progression of alcohol-related liver cirrhosis.
Subject(s)
Bilirubin , Tyrosine , Humans , Albumins , Bile Acids and Salts , Feces , Liver Cirrhosis, Alcoholic/diagnosis , Methionine , PhenylalanineABSTRACT
The mechanical properties of a stem cell culture substrate significantly impact cell adhesion, survival, migration, proliferation, and differentiation in vitro. A major challenge in engineering artificial stem cell substrate is to properly identify the relevant physical features of native stem cell niches, which are likely different for each stem cell type. The behavior of tendon stem cells has potentially significant implications for tendon repair. Here, microfiber scaffolds with various modulus of elasticity are fabricated by near-field electrospinning, and their regulating effects on the in vitro behavior of tendon stem cells (TSCs) are discussed in this study. The number of pseudopodia shows a biphasic relationship with the modulus of scaffold. The proliferation, polarization ratio and alignment degree along the fibers of the TSCs increase with the increase of fiber modulus. TSCs cultured on the scaffold with moderate modulus (1429 MPa) show the upregulation of tendon-specific genes (Col-I, Tnmd, SCX and TNCF). These microfiber scaffolds provide great opportunities to modulate TSCs behavior at the micrometer scales. In conclusion, this study provides an instructive mechanical microenvironment for TSCs behaviors and may lead to the development of desirable engineered artificial stem cell substrate for tendon healing.
Subject(s)
Tissue Engineering , Tissue Scaffolds , Tissue Scaffolds/chemistry , Tendons , Stem Cells , Cell Differentiation/genetics , Gene Expression , Cell Proliferation , Gene Expression RegulationABSTRACT
Background: Laparoendoscopic single-site (LESS) surgery is performed to further narrow the incisions and reduce tissue injury. It has been more than10 years since the surgery was first described. However, there is still no report on the results of 10-year follow-up. This study evaluated the use of long-term oncology and the renal outcomes of LESS radical nephrectomy (LESS-RN) in the treatment of localized renal cancer. Methods: We retrospectively analyzed the clinical data of patients treated with LESS-RN at Changhai Hospital from 2009 to 2012. Patients with localized kidney cancer who were followed-up for at least 10 years were included in the study. The baseline data and major perioperative outcome variables were analyzed. Overall survival (OS) and cancer-specific survival (CSS) were calculated using the Kaplan-Meier method. Results: A total of 48 patients were included in the study, which had a median follow-up of 11 years (interquartile range, 10.7-11.8 years). The 10-year OS and CSS rates were 87.5% [42/48; 95% confidence interval (CI): 0.778-0.972] and 97.9% (47/48; 95% CI: 0.937-1.021), respectively. At the most recent follow-up, there were 5 patients with a chronic kidney disease stage ≥3. Among these 5 patients, 3 developed uremia and required continuous dialysis. Conclusions: For localized renal cancer, LESS-RN is safe and effective with excellent long-term oncology controllability and good functional outcomes. Prospective studies with large sample sizes need to be conducted to validate our results.
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INTRODUCTION: Previous studies have shown that abnormal sleep architectures are the important indicator for diagnosing MDD and predicting the efficacy of antidepressants. However, few studies have focused specifically on adolescents. OBJECTIVE: To explore the relationship between abnormal sleep features, including PSG parameters and scale evaluation, and the onset of adolescent MDD, as well as early SSRIs efficacy. METHODS: 102 adolescent MDD patients (age 12 to 19-year-old) and 41 similarly age-marched controls were recruited. Demographic data, the HAMD24 and the PSQI scale assessment scores were collected at baseline, latter two were also collected at follow-up. Part of the participants underwent a minimum 7-d medication-free period, and two consecutive night polysomnography. In the follow-up study, MDD patients were treated with standardized SSRIs. Treatment response was assessed every two weeks. RESULTS: MDD subjects' parental marital status, REM-sleep latency, N2, N2%, N3, REM-sleep duration, REM % showed significant differences at baseline. REM-sleep latency showed significant prediction of the onset of MDD. The HAMD24 and PSQI scale assessment scores decreased over time in the follow-up study. Specifically, the sleep disorder factor score of HAMD24, the scores of PSQI sleep latency, sleep disorder, sleep efficiency and total score showed significantly differences between responder and non-responder groups. PSQI baseline moderate group showed significant prediction of the early efficacy of SSRIs. CONCLUSION: Abnormal sleep PSG parameters and self-evaluation could be predictors for the adolescent MDD onset and early SSRIs efficacy.
Subject(s)
Selective Serotonin Reuptake Inhibitors , Sleep , Humans , Adolescent , Child , Young Adult , Adult , Follow-Up Studies , Sleep/physiology , Antidepressive Agents , PolysomnographyABSTRACT
During the evolution of angiosperm flowers, some floral traits may undergo certain changes in order to participate in screening. The stamens and pistils of Delphinium caeruleum are covered by two "door-like" staminodes, the evolutionary function of which, however, is quite unknown. In this study, we investigated whether D. caeruleum staminodes acted as visitor filters by assessing the respective strengths of staminodes and visitor insects (six bee species). We measured the operative strength required to open the staminodes and the strength that insects were capable of exerting using a biological tension sensor. Furthermore, we compared the strength required to open staminodes at different phases of the flowering period (male and female phases) and the strength of different visitors (visitors and non-visitors of D. caeruleum). The results showed that the strength needed to open staminodes in the male phase was significantly higher than that in the female phase. There was no significant difference between the strength exerted by visitors and required by staminodes of D. caeruleum in the male phase, but the visitor strength was significantly higher than that required to open staminodes in the female phase flowers. The strength of non-visitors was significantly lower than that required to open staminodes in the male phase. Furthermore, there was a significant positive association between the strength and the body weight of the bees. These results highlighted the observation that only strong visitors could press the two staminodes to access the sex organs and achieve successful pollination. Furthermore, these results revealed the function of pollinator screening by the staminodes of D. caeruleum. The biomechanical approach to the study of flowers allowed us to address relevant ecological and evolutionary questions of the plant-pollinator interaction and explore the functional modules within the flower structure in other plant species.
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microRNAs (miRNA) in extracellular vesicles (EVs) have been investigated as potential biomarkers for pancreatic ductal adenocarcinoma (PDAC). However, a mixed population of EVs is often obtained using conventional exosome isolation methods for biomarker development. EVs are derived from different cellular processes and present in various sizes, therefore miRNA expression among them is undoubtedly different. We developed a simple protocol utilizing sequential filtration and ultracentrifugation to separate PDAC EVs into three groups, one with an average diameter of more than 220 nm, named operational 3 (OP3); one with average diameters between 100-220 nm, named operational 2 (OP2); and another with average diameters around 100 nm, named operational 1 (OP1)). EVs were isolated from conditioned cell culture media and plasma of human PDAC xenograft mice and early stage PDAC patients, and verified by nanoparticle tracking, western blot, and electronic microscopy. We demonstrate that exosome specific markers are only enriched in the OP1 group. qRT-PCR analysis of miRNA expression in EVs from PDAC cells revealed that expression of miR-196a and miR-1246, two previously identified miRNAs highly enriched in PDAC cell-derived exosomes, is significantly elevated in the OP1 group relative to the other EV groups. This was confirmed using plasma EVs from PDAC xenograft mice and patients with localized PDAC. Our results indicate that OP1 can be utilized for the identification of circulating EV miRNA signatures as potential biomarkers for PDAC.
Subject(s)
Adenocarcinoma/metabolism , Exosomes/metabolism , Extracellular Vesicles/metabolism , MicroRNAs/metabolism , Pancreatic Neoplasms/metabolism , Aged , Aged, 80 and over , Animals , Blotting, Western , Cell Line, Tumor , Circulating MicroRNA/metabolism , Female , Humans , Male , Mice , Mice, Nude , Microscopy, Electron , Middle Aged , Pancreatic NeoplasmsABSTRACT
BACKGROUND: Homocysteine, folate, and vitamin B12 involved in 1-carbon metabolism are associated with cognitive disorders. We sought to investigate the relationships between these factors and delayed neurocognitive recovery (dNCR) after non-cardiac surgery. METHODS: This was a prospective observational study of patients (n = 175) who were ≥ 60 years of age undergoing non-cardiac surgery. Patients were evaluated preoperatively and for 1 week postoperatively by using neuropsychological tests and were divided into dNCR or non-dNCR groups according to a Z-score ≤ - 1.96 on at least two of the tests. The relationship between the occurrence of dNCR and preoperative levels of homocysteine, folate, and vitamin B12 was analyzed. Univariate and multivariable logistic regression analyses were conducted to identify factors associated with dNCR. RESULTS: Delayed neurocognitive recovery was observed in 36 of 175 patients (20.6%; 95% confidence interval [CI], 14.5-26.6%) 1 week postoperatively. Patients who developed dNCR had significantly higher median [interquartile range (IQR)] homocysteine concentrations (12.8 [10.9,14.4] µmol/L vs 10.6 [8.6,14.7] µmol/L; P = 0.02) and lower folate concentrations (5.3 [4.2,7.3] ng/mL vs 6.9 [5.3,9.5] ng/mL; P = 0.01) than those without dNCR. Compared to the lowest tertile, the highest homocysteine tertile predicted dNCR onset (odds ratio [OR], 3.9; 95% CI, 1. 3 to 11.6; P = 0.02), even after adjusting for age, sex, education, and baseline Mini Mental State Examination. CONCLUSIONS: Elderly patients with high homocysteine levels who underwent general anesthesia for non-cardiac surgery have an increased risk of dNCR. This knowledge could potentially assist in the development of preventative and/or therapeutic measures. TRIAL REGISTRATION: NCT03084393 ( https://www.clinicaltrials.gov ).
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Nectar robbers, which affect plant fitness (directly or indirectly) in different degrees and in different ways, potentially constitute a significant part of mutualistic relationships. While the negative effects of nectar robbing on plant reproductive success have been widely reported, the positive effects remain unknown. The target of our study was to evaluate the effects of nectar robbers on the reproductive success of Symphytum officinale (Boraginaceae). We observed the behavior, species and times of visitors in the field, and we assessed the effect of nectar robbers on corolla abscission rate and time. To test the fitness of corolla abscission, we detected the changes in stigma receptivity, pollen viability, pollen amount and appendage opening size along with the time of flower blossom. The flowering dynamics and floral structure were observed to reveal the mechanism of self-pollination. Finally, pollen deposition seed set rate and fruit set rate were determined to estimate the effect of nectar robbers on reproduction success. We observed 14 species of visitors and 2539 visits in 50 h of observation; 91.7% of them were nectar robbers. The pressure and nectar removal of nectar robbers significantly promoted corolla abscission during a period when pollen grains are viable and the stigma is receptive. In addition, corolla abscission significantly increased the pollen deposition and seed setting rate. Our results demonstrate that nectar robbing contributes to enhancing seed production and positively and indirectly impacts the reproductive success of S. officinale. This mechanism involved the movement of anthers and indirect participation by nectar robbers, which was rarely investigated. Considering the multiple consequences of nectar robbing, understanding the impact of nectar robbers on plant reproduction is essential to comprehend the evolutionary importance of relationships between plants and their visitors.
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BACKGROUND: Exosomes are extracellular vesicles containing a variety of biological molecules including microRNAs (miRNAs). We have recently demonstrated that certain miRNA species are selectively and highly enriched in pancreatic cancer exosomes with miR-1246 being the most abundant. Exosome miRNAs have been shown to mediate intercellular communication in the tumor microenvironment and promote cancer progression. Therefore, understanding how exosomes selectively enrich specific miRNAs to initiate exosome miRNA signaling in cancer cells is critical to advancing cancer exosome biology. RESULTS: The aim of this study was to identify RNA binding proteins responsible for selective enrichment of exosome miRNAs in cancer cells. A biotin-labeled miR-1246 probe was used to capture RNA binding proteins (RBPs) from PANC-1 cells. Among the RBPs identified through proteomic analysis, SRSF1, EIF3B and TIA1 were highly associated with the miR-1246 probe. RNA immunoprecipitation (RIP) and electrophoretic mobility shift assay (EMSA) confirmed the binding of SRSF1 to miR-1246. Lentivirus shRNA knockdown of SRSF1 in pancreatic cancer cells selectively reduced exosome miRNA enrichment whereas GFP-SRSF1 overexpression enhanced the enrichment as analyzed by next generation small RNA sequencing and qRT-PCR. miRNA sequence motif analysis identified a common motif shared by 36/45 of SRSF1-associated exosome miRNAs. EMSA confirmed that shared motif decoys inhibit the binding of SRSF1 to the miR-1246 sequence. CONCLUSIONS: We conclude that SRSF1 mediates selective exosome miRNA enrichment in pancreatic cancer cells by binding to a commonly shared miRNA sequence motif. Video Abstract.
Subject(s)
Exosomes/genetics , MicroRNAs/metabolism , Neoplasms/genetics , Serine-Arginine Splicing Factors/metabolism , Base Sequence , Cell Line, Tumor , Exosomes/metabolism , Gene Expression Regulation , Humans , MicroRNAs/genetics , Nucleotide Motifs/genetics , Protein Binding , Reproducibility of ResultsABSTRACT
Covering: 2012 to 2019HemN-like radical S-adenosyl-l-methionine (SAM) enzymes have been recently disclosed to catalyze diverse chemically challenging reactions from primary to secondary metabolic pathways. In this highlight, we summarize the reaction examples catalyzed by HemN-like enzymes to date and the enzymatic mechanisms reported. From the recent mechanistic investigations, we reason that there is a shared initiating mechanism wherein a characteristic SAM methylene radical is proposed to abstract a hydrogen atom from an sp3 carbon or add onto an sp2 carbon center although variations occur thereafter from reaction to reaction, as well as providing a brief insight into some future prospects.
Subject(s)
Enzymes/chemistry , Enzymes/metabolism , S-Adenosylmethionine/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Coproporphyrinogen Oxidase/chemistry , Coproporphyrinogen Oxidase/metabolism , Duocarmycins/metabolism , Escherichia coli Proteins/metabolism , Heme/metabolism , Hydrogen , Methylation , Peptides, Cyclic/metabolism , Polyketides/metabolism , Protein Methyltransferases/metabolism , Thiazoles/metabolismABSTRACT
BACKGROUND: Altered expression of microRNAs (miRNAs) is known to contribute to cancer progression. miR-23b and miR-27b, encoded within the same miRNA cluster, are reported to have both tumor suppressive and oncogenic activity across human cancers, including breast cancer. METHODS: To clarify this dichotomous role in breast cancer, miR-23b and miR-27b were knocked out using CRISPR/Cas9 gene knockout technology, and the role of endogenous miR-23b and miR-27b was examined in a breast cancer model system in vitro and in vivo. RESULTS: Characterization of the knockout cells in vitro demonstrated that miR-23b and miR-27b are indeed oncogenic miRNAs in MCF7 breast cancer cells. miR-23b and miR-27b knockout reduced tumor growth in xenograft nude mice fed a standard diet, supporting their oncogenic role in vivo. However, when xenograft mice were provided a fish-oil diet, miR-27b depletion, but not miR-23b depletion, compromised fish-oil-induced suppression of xenograft growth, indicating a context-dependent nature of miR-27b oncogenic activity. CONCLUSIONS: Our results demonstrate that miR-23b and miR-27b are primarily oncogenic in MCF7 breast cancer cells and that miR-27b may have tumor suppressive activity under certain circumstances.
Subject(s)
Breast Neoplasms/genetics , MicroRNAs/genetics , Animals , Breast Neoplasms/diet therapy , Breast Neoplasms/pathology , CRISPR-Cas Systems , Cell Movement , Cell Proliferation , Cell Survival/drug effects , Dietary Supplements , Female , Fish Oils/administration & dosage , Fish Oils/pharmacology , Gene Expression Regulation, Neoplastic , Gene Knockout Techniques , Humans , MCF-7 Cells , Mice, Nude , Xenograft Model Antitumor AssaysABSTRACT
miR-1246 is considered an oncomiR in various cancer types. However, the origin and biogenesis of miR-1246 remain controversial which often leads to misinterpretation of its detection and biological function, and inevitably masking its mechanisms of action. Using next generation small RNA sequencing, CRISPR-Cas9 knockout, siRNA knockdown and the poly-A tailing SYBR qRT-PCR, we examined the biogenesis of exosomal miR-1246 in human cancer cell model systems. We found that miR-1246 is highly enriched in exosomes derived from human cancer cells and that it originates from RNU2-1, a small nuclear RNA and essential component of the U2 complex of the spliceosome. Knockdown of Drosha and Dicer did not reduce exosomal miR-1246 levels, indicating that exosomal miR-1246 is generated in a Drosha- and Dicer-independent manner. Direct digestion of cellular lysate by RNase A and knockdown of the RNU2-1 binding protein SmB/B' demonstrated that exosomal miR-1246 is a RNU2-1 degradation product. Furthermore, the GCAG motif present in the RUN2-1 transcript was shown to mediate miR-1246 enrichment in cancer exosomes. We conclude that exosome miR-1246 is derived from RNU2-1 degradation through a non-canonical microRNA biogenesis process. These findings reveal the origin of an oncomiR in human cancer cells, providing guidance in understanding miR-1246 detection and biological function. Abbreviations: CRISPR, Clustered Regularly Interspaced Short Palindromic Repeats; miRNA, microRNA; PDAC, pancreatic ductal adenocarcinoma; RNU2-1, U2 small nuclear RNA; RT-PCR, Reverse transcription polymerase chain reaction; sgRNA, single-guide RNA.
Subject(s)
Exosomes/genetics , MicroRNAs/metabolism , Neoplasms/genetics , Cell Line , Cell Line, Tumor , Humans , MicroRNAs/chemistry , MicroRNAs/genetics , Neoplasms/metabolism , Nucleotide Motifs , RNA, Nuclear/metabolismABSTRACT
BACKGROUND: Exosomes are small membrane-bound vesicles that contribute to tumor progression and metastasis by mediating cell-to-cell communication and modifying the tumor microenvironment at both local and distant sites. However, little is known about the predominant factors in exosomes that contribute to breast cancer (BC) progression. MTA1 is a transcriptional co-regulator that can act as both a co-activator and co-repressor to regulate pathways that contribute to cancer development. MTA1 is also one of the most up-regulated proteins in cancer, whose expression correlates with cancer progression, poor prognosis and increased metastatic potential. METHODS: We identified MTA1 in BC exosomes by antibody array and confirmed expression of exosome-MTA1 across five breast cancer cells lines. Ectopic expression of tdTomato-tagged MTA1 and exosome transfer were examined by fluorescent microscopy. CRISPR/Cas9 genetic engineering was implemented to knockout MTA1 in MCF7 and MDA-MB-231 breast cancer cells. Reporter assays were used to monitor hypoxia and estrogen receptor signaling regulation by exosome-MTA1 transfer. RESULTS: Ectopic overexpression of tdTomato-MTA1 in BC cell lines demonstrated exosome transfer of MTA1 to BC and vascular endothelial cells. MTA1 knockout in BC cells reduced cell proliferation and attenuated the hypoxic response in these cells, presumably through its co-repressor function, which could be rescued by the addition of exosomes containing MTA1. On the other hand, consistent with its co-activator function, estrogen receptor signaling was enhanced in MTA1 knockout cells and could be reversed by addition of MTA1-exosomes. Importantly, MTA1 knockout sensitized hormone receptor negative cells to 4-hydroxy tamoxifen treatment, which could be reversed by the addition of MTA1-exosomes. CONCLUSIONS: This is the first report showing that BC exosomes contain MTA1 and can transfer it to other cells resulting in changes to hypoxia and estrogen receptor signaling in the tumor microenvironment. These results, collectively, provide evidence suggesting that exosome-mediated transfer of MTA1 contributes to BC progression by modifying cellular responses to important signaling pathways and that exosome-MTA1 may be developed as a biomarker and therapeutic target for BC.