Machine Learning Classifiers for Twitter Surveillance of Vaping: Comparative Machine Learning Study.

BACKGROUND: Twitter presents a valuable and relevant social media platform to study the prevalence of information and sentiment on vaping that may be useful for public health surveillance. Machine learning classifiers that identify vaping-relevant tweets and characterize sentiments in them can underpin a Twitter-based vaping surveillance system. Compared with traditional machine learning classifiers that are reliant on annotations that are expensive to obtain, deep learning classifiers offer the advantage of requiring fewer annotated tweets by leveraging the large numbers of readily available unannotated tweets. OBJECTIVE: This study aims to derive and evaluate traditional and deep learning classifiers that can identify tweets relevant to vaping, tweets of a commercial nature, and tweets with provape sentiments. METHODS: We continuously collected tweets that matched vaping-related keywords over 2 months from August 2018 to October 2018. From this data set of tweets, a set of 4000 tweets was selected, and each tweet was manually annotated for relevance (vape relevant or not), commercial nature (commercial or not), and sentiment (provape or not). Using the annotated data, we derived traditional classifiers that included logistic regression, random forest, linear support vector machine, and multinomial naive Bayes. In addition, using the annotated data set and a larger unannotated data set of tweets, we derived deep learning classifiers that included a convolutional neural network (CNN), long short-term memory (LSTM) network, LSTM-CNN network, and bidirectional LSTM (BiLSTM) network. The unannotated tweet data were used to derive word vectors that deep learning classifiers can leverage to improve performance. RESULTS: LSTM-CNN performed the best with the highest area under the receiver operating characteristic curve (AUC) of 0.96 (95% CI 0.93-0.98) for relevance, all deep learning classifiers including LSTM-CNN performed better than the traditional classifiers with an AUC of 0.99 (95% CI 0.98-0.99) for distinguishing commercial from noncommercial tweets, and BiLSTM performed the best with an AUC of 0.83 (95% CI 0.78-0.89) for provape sentiment. Overall, LSTM-CNN performed the best across all 3 classification tasks. CONCLUSIONS: We derived and evaluated traditional machine learning and deep learning classifiers to identify vaping-related relevant, commercial, and provape tweets. Overall, deep learning classifiers such as LSTM-CNN had superior performance and had the added advantage of requiring no preprocessing. The performance of these classifiers supports the development of a vaping surveillance system.

Identification of integrin heterodimers functioning on the surface of undifferentiated porcine primed embryonic stem cells.

In vitro expansion of undifferentiated porcine primed embryonic stem (ES) cells is facilitated by use of non-cellular niches that mimic three-dimensional (3D) microenvironments enclosing an inner cell mass of porcine blastocysts. Therefore, we investigated the integrin heterodimers on the surface of undifferentiated porcine primed ES cells for the purpose of developing a non-cellular niche to support in vitro maintenance of the self-renewal ability of porcine primed ES cells. Immunocytochemistry and a fluorescence immunoassay were performed to assess integrin α and ß subunit levels, and attachment and antibody inhibition assays were used to evaluate the function of integrin heterodimers. The integrin α3 , α5 , α6 , α9 , αV , and ß1 subunits, but not the α1 , α2 , α4 , α7 , and α8 subunits, were identified on the surface of undifferentiated porcine primed ES cells. Subsequently, significant increase of their adhesion to fibronectin, tenascin C, and vitronectin were observed and functional blocking of integrin heterodimer α5 ß1 , α9 ß1 , or αV ß1 showed significantly inhibited adhesion to fibronectin, tenascin C, or vitronectin. No integrin α6 ß1 heterodimer-mediated adhesion to laminin was detected. These results demonstrate that active α5 ß1 , α9 ß1 , and αV ß1 integrin heterodimers are present on the surface of undifferentiated porcine primed ES cells, together with inactive integrin α3 (presumed) and α6 subunits.

Delivery of episomal vectors into primary cells by means of commercial transfection reagents.

Although episomal vectors are commonly transported into cells by electroporation, a number of electroporation-derived problems have led to the search for alternative transfection protocols, such as the use of transfection reagents, which are inexpensive and easy to handle. Polyplex-mediated transport of episomal vectors into the cytoplasm has been conducted successfully in immortalized cell lines, but no report exists of successful transfection of primary cells using this method. Accordingly, we sought to optimize the conditions for polyplex-mediated transfection for effective delivery of episomal vectors into the cytoplasm of primary mouse embryonic fibroblasts. Episomal vectors were complexed with the commercially available transfection reagents Lipofectamine 2000, FuGEND HD and jetPEI. The ratio of transfection reagent to episomal vectors was varied, and the subsequent transfection efficiency and cytotoxicity of the complexes were analyzed using flow cytometry and trypan blue exclusion assay, respectively. No cytotoxicity and the highest transfection yield were observed when the ratio of transfection reagent to episomal vector was 4 (v/wt) in the cases of Lipofectamine 2000 and FuGENE HD, and 2 in the case of jetPEI. Of the three transfection reagents tested, jetPEI showed the highest transfection efficiency without any cytotoxicity. Thus, we confirmed that the transfection reagent jetPEI could be used to effectively deliver episomal vectors into primary cells without electroporation.

Generation of priming mesenchymal stem cells with enhanced potential to differentiate into specific cell lineages using extracellular matrix proteins.

Poor understanding of the differentiation of mesenchymal stem cells (MSCs) has resulted in a low differentiation yield, and has hindered their application in medicine. As a solution, priming MSCs sensitive to signaling, thus stimulating differentiation into a specific cell lineage, may improve the differentiation yield. To demonstrate this, priming MSCs were produced by using a gelatin matrix for the isolation of primary MSCs from bone-marrow-derived primary cells. Subsequently, cellular characteristics and sensitivity to specific differentiation signals were analyzed at passage five. Compared to non-priming MSCs, priming MSCs showed no significant differences in cellular characteristics, but demonstrated a significant increase in sensitivity to neurogenic differentiation signals. These results demonstrate that generation of priming MSCs by specific extracellular signaling increases the rate of differentiation into a cell-specific lineage.

Development of a High-Yield Isolation Protocol Optimized for the Retrieval of Active Muscle Satellite Cells from Mouse Skeletal Muscle Tissue.

Background and Objectives: Difficulties often encountered in separating and purifying active muscle satellite cells (MSCs) from skeletal muscle tissues have limited the supply of cells for muscle therapy and artificial meat production. Here, we report an effective isolation protocol to economically and conveniently retrieve active MSCs from skeletal muscle tissues in mice. Methods and Results: We optimized an enzyme-based tissue digestion protocol for isolating skeletal muscle-derived primary cell population having a large number of active MSCs and described a method of differential plating (DP) for improving purity of active MSCs from skeletal muscle-derived primary cell population. Then, the age of the mouse appropriate to the isolation of a large number of active MSCs was elucidated. The best isolation yield of active MSCs from mouse skeletal muscle tissues was induced by the application of DP method to the primary cell population harvested from skeletal muscle tissues of 2-week-old mice digested in 0.2% (w/v) collagenase type II for 30 min at 37℃ and then in 0.1% (w/v) pronase for 5 min at 37℃. Conclusions: The protocol we developed not only facilitates the isolation of MSCs but also maximizes the retrieval of active MSCs. Our expectation is that this protocol will contribute to the development of original technologies essential for muscle therapy and artificial meat industrialization in the future.

Additive Effect of CD73 Inhibitor in Colorectal Cancer Treatment With CDK4/6 Inhibitor Through Regulation of PD-L1.

BACKGROUND & AIMS: Although cancer immunotherapies are effective for advanced-stage cancers, there are no clinically approved immunotherapies for colon cancers (CRCs). Therefore, there is a high demand for the development of novel therapies. Extracellular adenosine-mediated signaling is considered a promising target for advanced-stage cancers that are nonresponsive to programmed death 1 (PD-1)-/programmed death-ligand 1 (PD-L1)-targeted immunotherapies. In this study, we aimed to elucidate novel tumorigenic mechanisms of extracellular adenosine. METHODS: To investigate the effects of extracellular adenosine on tumor-associated macrophages, peripheral blood-derived human macrophages were treated with adenosine and analyzed using flow cytometry and Western blot. Changes in adenosine-treated macrophages were further assessed using multi-omics analysis, including total RNA sequencing and proteomics. Colon cancer mouse models were used to measure the therapeutic efficacy of AB680 and palbociclib. We also used tissue microarrays of patients with CRC, to evaluate their clinical relevance. RESULTS: Extracellular adenosine-mediated reduction of cyclin D1 (CCND1) was found to be critical for the regulation of immune checkpoint molecules and PD-L1 levels in human macrophages, indicating that post-translational modification of PD-L1 is affected by adenosine. A potent CD73 selective inhibitor, AB680, reversed the effects of adenosine on CCND1 and PD-L1. This result strongly suggests that AB680 is a combinatory therapeutic option to overcome the undesired side effects of the cyclin-dependent kinase 4/6 inhibitor, palbociclib, which increases PD-L1 expression in tumors. Because palbociclib is undergoing clinical trials for metastatic CRC in combination with cetuximab (clinical trial number: NCT03446157), we validated that the combination of AB680 and palbociclib significantly improved anti-tumor efficacy in CRC animal models, thereby highlighting it as a novel immunotherapeutic strategy. We further assessed whether the level of CCND1 in tumor-associated macrophages was indeed reduced in tumor sections obtained from patients with CRC, for evaluating the clinical relevance of this strategy. CONCLUSIONS: In this study, we demonstrated that a novel combination therapy of AB680 and palbociclib may be advantageous for the treatment of CRC.

Investigation of Age-Related Changes in the Skin Microbiota of Korean Women.

The microbiota of human skin is influenced by host and environmental factors. To determine if chronological age influences the composition of the skin microbiota on the forehead and hands, 73 Korean women were sorted into one of three age groups: (1) 10-29 years (n = 24), (2) 30-49 years (n = 21), and (3) 50-79 years (n = 28). From the 73 women, 146 skin samples (two skin sites per person) were collected. 16S rRNA gene amplicon sequencing was then conducted to analyze the skin microbiota. The overall microbial distribution varied on the forehead but was similar on the hands across the three age groups. In addition, the composition of the skin microbiota differed between the forehead and hands. Commensal microbiota, such as Streptococcus, Staphylococcus, Cutibacterium, and Corynebacterium, which contribute to maintaining skin health via dominant occupation, were affected by increasing age on forehead and hand skin. Alpha diversity indices increased significantly with age on forehead skin. This study indicates that older people may be more susceptible to pathogenic invasions due to an imbalanced skin microbiota resulting from age-related changes. The results of our study may help develop new strategies to rebalance skin microbiota shifted during aging.

Generation of embryonic stem cells derived from the inner cell mass of blastocysts of outbred ICR mice.

Embryonic stem cells (ESCs) derived from outbred mice which share several genetic characteristics similar to humans have been requested for developing stem cell-based bioengineering techniques directly applicable to humans. Here, we report the generation of ESCs derived from the inner cell mass of blastocysts retrieved from 9-week-old female outbred ICR mice mated with 9-week-old male outbred ICR mice (ICRESCs). Similar to those from 129/Ola mouse blastocysts (E14ESCs), the established ICRESCs showed inherent characteristics of ESCs except for partial and weak protein expression and activity of alkaline phosphatase. Moreover, ICRESCs were not originated from embryonic germ cells or pluripotent cells that may co-exist in outbred ICR strain-derived mouse embryonic fibroblasts (ICRMEFs) used for deriving colonies from inner cell mass of outbred ICR mouse blastocysts. Furthermore, instead of outbred ICRMEFs, hybrid B6CBAF1MEFs as feeder cells could sufficiently support in vitro maintenance of ICRESC self-renewal. Additionally, ICRESC-specific characteristics (self-renewal, pluripotency, and chromosomal normality) were observed in ICRESCs cultured for 40th subpassages (164 days) on B6CBAF1MEFs without any alterations. These results confirmed the successful establishment of ESCs derived from outbred ICR mice, and indicated that self-renewal and pluripotency of the established ICRESCs could be maintained on B6CBAF1MEFs in culture.

Effects of Culture Dimensions on Maintenance of Porcine Inner Cell Mass-Derived Cell Self-Renewal.

Despite the fact that porcine embryonic stem cells (ESCs) are a practical study tool, in vitro long-term maintenance of these cells is difficult in a two-dimensional (2D) microenvironment using cellular niche or extracellular matrix proteins. However, a three-dimensional (3D) microenvironment, similar to that enclosing the inner cell mass of the blastocyst, may improve in vitro maintenance of self-renewal. Accordingly, as a first step toward constructing a 3D microenvironment optimized to maintain porcine ESC self-renewal, we investigated different culture dimensions for porcine ICM-derived cells to enhance the maintenance of self-renewal. Porcine ICM-derived cells were cultured in agarose-based 3D hydrogel with self-renewal-friendly mechanics and in 2D culture plates with or without feeder cells. Subsequently, the effects of the 3D microenvironment on maintenance of self-renewal were identified by analyzing colony formation and morphology, alkaline phosphatase (AP) activity, and transcriptional and translational regulation of self-renewal-related genes. The 3D microenvironment using a 1.5% (w/v) agarose-based 3D hydrogel resulted in significantly more colonies with stereoscopic morphology, significantly improved AP activity, and increased protein expression of self-renewal-related genes compared to those in the 2D microenvironment. These results demonstrate that self-renewal of porcine ICM-derived cells can be maintained more effectively in a 3D microenvironment than in a 2D microenvironment. These results will help develop novel culture systems for ICM-derived cells derived from diverse species, which will contribute to stimulating basic and applicable studies related to ESCs.

Gelatin Directly Enhances Neurogenic Differentiation Potential in Bone Marrow-Derived Mesenchymal Stem Cells Without Stimulation of Neural Progenitor Cell Proliferation.

Gelatin has been reported to induce generation of mesenchymal stem cells (MSCs) with enhanced potential of differentiation into neuronal lineage cells. However, the presence of various cell types besides MSCs in bone marrow has raised doubts about the effects of gelatin. In the following report, we determined whether gelatin can directly enhance neurogenic differentiation potential in MSCs without proliferation of neural progenitor cells (NPCs). MSCs comprised a high proportion of bone marrow-derived primary cells (BMPCs) and gelatin induced significant increases in MSC proliferation during primary culture, and the proportion of MSCs was maintained at more than 99% throughout the subculture. However, NPCs comprised a low percentage of BMPCs and a decrease in proliferation was detected despite gelatin treatment during the primary culture, and the proportion of subcultured NPCs gradually decreased. In a similar manner, MSCs exposed to gelatin during primary culture showed more enhanced neurogenic differentiation ability than those not exposed to gelatin. Together, these results demonstrate that gelatin directly enhances neurogenic differentiation in bone marrow-derived MSCs without stimulating NPC proliferation.

Association between Nutrition Label Reading and Nutrient Intake in Korean Adults: Korea National Health and Nutritional Examination Survey, 2007-2009 (KNHANES IV).

BACKGROUND: Nutrition labels provide various information on the nutrient contents of food. However, despite the recent increase in the interest in dietary intake and expansion of related policies, studies on the association between nutrition label reading and dietary intake are lacking in Korea. METHODS: This study analyzed the 2007-2009 KNHANES (Korean National Health and Nutrition Examination Survey) data. To examine macronutrients and micronutrients intake according to nutrition label reading, analysis of covariance was used. Multiple logistic regression analysis was also used to examine the association between adherence to dietary reference intake and nutrition label reading. RESULTS: Nutrition label reading was significantly high among women, youth, and those with high education and high household income. Nutrition label reading was associated with higher intake of calcium and vitamin C in men and the lower intake of calorie, carbohydrates and higher energy ratio of protein in women. Additionally, male nutrition label readers were associated with adherence to dietary reference intake of fiber (odds ratio [OR], 2.00; 95% confidence interval [CI], 1.23 to 3.26) and calcium (OR, 1.26; 95% CI, 1.03 to 1.54). In women, there were no significant differences in the adherence to the dietary reference intake in fat, fiber, sodium, potassium, and calcium according to the nutrition label reading. CONCLUSION: In men, nutrition label reading was associated with healthier intake of several micronutrients, although this was not observed in women. Consideration for clearly reporting vulnerable micronutrients in nutrition labels is necessary.

Mass production of early-stage bone-marrow-derived mesenchymal stem cells of rat using gelatin-coated matrix.

Although preparation of early-stage bone-marrow-derived mesenchymal stem cells (BM-MSCs) is critical for successful cell transplantation therapy, no culture system offers a sufficient number of early-stage BM-MSCs for cell transplantation. Accordingly, we developed a culture system capable of producing a large number of early-stage BM-MSCs by using gelatin-coated matrix. The greatest retrieval and proliferation rates of the earliest-stage rat BM-MSCs were detected in bone-marrow-derived cells cultured on 1% (wt/v) gelatin-coated matrix, which showed significantly greater colony forming unit-fibroblast number, diameter, and total cell number. Moreover, continuous culture of the earliest-stage BM-MSCs on 1% (wt/v) gelatin-coated matrix resulted in a maximum of 21.2 ± 2.7 fold increase in the cumulative total number of early-stage BM-MSCs at passage 5. BM-MSCs generated in large quantities due to a reduced doubling time and an increased yield of cell population in S/G2/M phase showed typical fibroblast-like morphology and no significant differences in BM-MSC-related surface marker expression and differentiation potential, except for an increased ratio of differentiation into a neurogenic lineage. The use of gelatin-coated matrix in the retrieval and culture of BM-MSCs contributes greatly to the effective isolation and mass production of early-stage BM-MSCs.