Loss of Sirt6 in adipocytes impairs the ability of adipose tissue to adapt to intermittent fasting

Wu Dandan,방인혁,박병현,Bae Eun Ju 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

Intermittent fasting (IF) is gaining popularity for its effectiveness in improving overall health, including its effectiveness in achieving weight loss and euglycemia. The molecular mechanisms of IF, however, are not well understood. This study investigated the relationship between adipocyte sirtuin 6 (Sirt6) and the metabolic benefits of IF. Adipocyte-specific Sirt6-knockout (aS6KO) mice and wild-type littermates were fed a high-fat diet (HFD) ad libitum for four weeks and then subjected to 12 weeks on a 2:1 IF regimen consisting of two days of feeding followed by one day of fasting. Compared with wild-type mice, aS6KO mice subjected to HFD + IF exhibited a diminished response, as reflected by their glucose and insulin intolerance, reduced energy expenditure and adipose tissue browning, and increased inflammation of white adipose tissue. Sirt6 deficiency in hepatocytes or in myeloid cells did not impair adaptation to IF. Finally, the results indicated that the impaired adipose tissue browning and reduced expression of UCP1 in aS6KO mice were accompanied by downregulation of p38 MAPK/ATF2 signaling. Our findings indicate that Sirt6 in adipocytes is critical to obtaining the improved glucose metabolism and metabolic profiles conferred by IF and that maintaining high levels of Sirt6 in adipocytes may mimic the health benefits of IF.

CBX7 Rejuvenates Late Passage Dental Pulp Stem Cells by Maintaining Stemness and Pro-angiogenic Ability

Wu Yu,Li Bing,Yu Dandan,Zhou Zhixuan,Shen Ming,Jiang Fei 한국조직공학과 재생의학회 2023 조직공학과 재생의학 Vol.20 No.3

BACKGROUND: Ever-growing tissue regeneration causes pressing need for large population of stem cells. However, extensive cell expansion eventually leads to impaired regenerative potentials. In this study, chromobox protein homolog 7 (CBX7) was overexpressed to rejuvenate late passage dental pulp stem cells (DPSCs-P9). METHODS: The recruitment of copper ions (Cu2?)-activated hypoxia-inducible factor-1a (HIF-1a) to the CBX7 gene promoter was confirmed by chromatin immunoprecipitation assay. Functions subsequent to Cu2?-induced or recombinant overexpression of CBX7 on proliferation, multipotency, odontoblastic differentiation and angiogenesis were investigated in vitro, while murine subcutaneous transplantation model was used to further detect the effects of Cu2?-induced CBX7 overexpression in vivo. RESULTS: Our data displayed that CBX7 overexpression maintain proliferation and multipotency of DPSCs-P9 almost as strong as those of DPSCs-P3. Both gene level of odontoblast-lineage markers and calcium precipitation were nearly the same between CBX7 overexpressed DPSCs-P9 and normal DPSCs-P3. Moreover, we also found upregulated expression of vascular endothelial growth factor in DPSCs-P9 with CBX7 overexpression, which increased the number of capillary-like structures and migrating co-cultured human umbilical vein endothelial cells as well. These findings indicate CBX7 as an effective factor to rejuvenate late passage stem cells insusceptible to cell expansion. Cu2? has been proved to achieve CBX7 overexpression in DPSCs through the initiation of HIF-1a-CBX7 cascade. Under Cu2? stimulation since P3, DPSCs-P9 exhibited ameliorated regenerative potential both in vitro and in vivo. CONCLUSION: Long-term stimulation of Cu2? to overexpress CBX7 could be a new strategy to manufacture large population of self-renewing stem cells.

Service Quality Gap Model for Analysis and Improvement of Plastic Surgery Customer Satisfaction in South Korea

Dandan Yu,Lanmeng Wu,LIUZIYANG 한국무역통상학회 2020 무역통상학회지 Vol.20 No.5

The purpose of this study is to examine the experiences of customers who go to Korea to undergo plastic surgery. This study applies the quality-of-service gap model to understand and analyze customer satisfaction and service demand and to know various measures and suggestions to improve medical services. A questionnaire survey is adopted according to the basic theory of the service quality gap model. Based on actual conditions of hospital work in Korea, the gap model of medical service quality is established. SPSS22.0 statistical package was used to analyze and process data. Results show that plastic surgery customers’ perception of medical services is higher than expected. At the same time, plastic surgery customers indicate the highest evaluation of the quality of medical services. These customers have the highest expectation of assurance in medical service quality and the lowest expectation on empathy. Among the plastic surgery clients in various age groups, the younger ones exhibit greater difference between the expected value and actual perceived value in terms of the reliability of medical service quality. Therefore, we can conclude that the service quality gap model is feasible in analyzing and improving the satisfaction of hospital patients. This model is a reliable theoretical reference that hospital administrators can use to address issues related to medical service quality.

Structural Studies of G Protein-Coupled Receptors

Dandan Zhang,Beili Wu,Qiang Zhao 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.10

G protein-coupled receptors (GPCRs) constitute the largest and the most physiologically important membrane protein family that recognizes a variety of environmental stimuli, and are drug targets in the treatment of numerous diseases. Recent progress on GPCR structural studies shed light on molecular mechanisms of GPCR ligand recognition, activation and allosteric modulation, as well as structural basis of GPCR dimerization. In this review, we will discuss the structural features of GPCRs and structural insights of different aspects of GPCR biological functions.

Study on the Mechanical Characteristics of Urban Sludge Solidified by Industrial Waste

Liuyan Wu,Qiang Wang,Dandan Ge,Huangrui Xu,Guojun Cai 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7

Urban sludge is an extensive volume with a prominent environmental impact. The researchexplored an application technology for converting urban sludge into a usable improved soilresource by using industrial waste, providing a new reference for the reuse of industrial waste. In this study, three industrial wastes, namely ground granulated blast slag, calcium carbideresidue, and desulfurized gypsum, were used as curing agents to solidify the urban sludge. Based on the unconfined compressive strength (UCS) test and chamber analysis, the effects ofcuring agent dosing and maintenance age of sludge-cured soil on the UCS and stress- strainwere studied. The results showed that with the increase of curing agent, the UCS of cured soilfirst increased and then decreased, and the breaking strain showed a decreasing trend. Theoptimum ratio of materials was sludge: calcium carbide residue: ground granulated blast slag:desulfurization gypsum = 100:15:15:5, record this material ratio as C15G15D5. Moreover,trials showed that C15G15D5 cured the sludge soil better than the cement alone, whichachieved the purpose of reusing the three industrial wastes and urban sludge. It was analyzedthat the hydrated calcium silicate (C-S-H), calcium aluminate (C-A-H) and ettringite (AFt) inthe hydration products were produced to make the soil skeleton stronger and enhance thestrength of the sludge-cured soil.

Structural Studies of G Protein-Coupled Receptors

Zhang, Dandan,Zhao, Qiang,Wu, Beili Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.10

G protein-coupled receptors (GPCRs) constitute the largest and the most physiologically important membrane protein family that recognizes a variety of environmental stimuli, and are drug targets in the treatment of numerous diseases. Recent progress on GPCR structural studies shed light on molecular mechanisms of GPCR ligand recognition, activation and allosteric modulation, as well as structural basis of GPCR dimerization. In this review, we will discuss the structural features of GPCRs and structural insights of different aspects of GPCR biological functions.

The Influence of Service Quality of E-Commerce on Consumer Satisfaction Degree and Repurchase Intention : The Case of Leisure Food E-Commerce in China

Lanmeng Wu,Dandan Yu,Ziyang Liu 한국무역통상학회 2020 무역통상학회지 Vol.20 No.6

In recent years, the proportion of leisure food in E-commerce platforms has kept increasing year by year for its attribute characteristics and the rapid development of E-commerce platforms, but some problems have also emerged. This paper aims at studying the influence of service quality on customer satisfaction and repurchase intention by means of specific division of service quality of E-commerce with leisure food E-commerce being an example. In this paper, the collected data is analyzed in terms of reliability and validity, factor analysis and construction of equation models in the form of questionnaires with software SPSS and AMOS. The conclusions obtained from analysis include: 1. Customers’ expectation before purchasing has a significant positive impact on consumer satisfaction. 2. The assumption that E-commerce web design has a significant positive impact on consumer satisfaction is false. 3. E-commerce logistics has a significant positive impact on consumer satisfaction. 4. The quality of e-commerce products has a significant positive impact on consumers. 5. E-commerce after-sales service has a significant positive impact on consumer satisfaction. 6. Consumer satisfaction has a significant positive impact on repurchase intention.

Metallothionein MT1M Suppresses Carcinogenesis of Esophageal Carcinoma Cells through Inhibition of the Epithelial-Mesenchymal Transition and the SOD1/PI3K Axis

Li, Dandan,Peng, Weiyan,Wu, Bin,Liu, Huan,Zhang, Ruizhen,Zhou, Ruiqin,Yao, Lijun,Ye, Lin Korean Society for Molecular and Cellular Biology 2021 Molecules and cells Vol.44 No.4

Metallothionein (MT1M) belongs to a family of cysteinerich cytosolic protein and has been reported to be a tumor suppressor gene in multiple cancers. However, its role in esophageal carcinoma carcinogenesis remains unclear. In this study, MT1M expression was correlated with tumor type, stage, drinking and smoking history, as well as patient survival. We also studied the regulation and biological function of MT1M in esophageal squamous cell carcinoma (ESCC). We have found that MT1M is significantly downregulated in ESCC tissues compared with adjacent non-cancer tissues. Furthermore, restoration of expression by treatment with the demethylation agent A + T showed that MT1M downregulation might be closely related to hypermethylation in its promoter region. Over-expression of MT1M in ESCC cells significantly altered cell morphology, induced apoptosis, and reduced colony formation, cell viability, migration and epithelial-mesenchymal transition. Moreover, based on reactive oxygen species (ROS) levels, a superoxide dismutase 1 (SOD1) activity assay and protein analysis, we verified that the tumor-suppressive function of MT1M was at least partially caused by its upregulation of ROS levels, downregulation of SOD1 activity and phosphorylation of the SOD1 downstream pathway PI3K/AKT. In conclusion, our results demonstrated that MT1M was a novel tumor-suppressor in ESCC and may be disrupted by promoter CpG methylation during esophageal carcinogenesis.

Radon-induced demethylation of Cdk2 CpG island in the rat lung

Cheng Wu,Qiu Chen,Jian Tong,Xin Xie,Fengmei Cui,Yang Jiao,Dandan Qi,Jihua Nie,Tom K. Hei,Qisheng Jiang 한국유전학회 2014 Genes & Genomics Vol.36 No.6

Radon exposure has been linked to lung carcinogenesisin both human and animal studies. The identificationof sequential changes in DNA methylation duringtumour progression and the elucidation of their interplaywith genetic changes will broaden our molecular understandingof this disease. Rats were exposed to 120 or 400working level months (WLM) of radon, lung pathologicalchanges were examined by haematoxylin and eosin staining,lung single cell suspension cell cycles were detected byflow cytometry, lung cell cycle regulated gene (Cdkn2a,P53, Cdk4/2, Mdm4/2 and Rb1 genes) expression wasquantified by real-time PCR and methylation of CpG islandsin the promoters of cell cycle-regulated genes were detectedby bisulfite sequencing PCR. The alveolar walls of rat lungsafter exposured to radon exhibited papillae and the lungbronchial epithelial cells stained positively for proliferatingcell nuclear antigen. The bronchial epithelial cells displayedsome hyperplasia after challenged by 400 WLM of radon. Moreover, G1 arrest decreased; Rb1, Mdm2/4, and Cdk2/4expression decreased and Cdk2 was demethylated at thesecond and sixth CpG loci from base pairs 3092704 to3092953 of chromosome 7. Cdk2 demethylation may beapplicable as a biomarker of early lung damage that wasinduced by radon and other environmental carcinogens.

Mechanical and Microscopic Properties of Copper-contaminated Soil Solidified with Calcium Carbide Residue, Metakaolin, and Desulfurization Gypsum under Freeze-thaw Cycles

Qiang Wang,Dandan Ge,Guojun Cai,Man Li,Liuyan Wu,Huangrui Xu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

The solidification/stabilization effect of heavy metal contaminated soils in frozen soil regions may be weakened. A novel binder comprising calcium carbide residue, metakaolin, and desulfurization gypsum was used to solidify and stabilize copper-contaminated soil subjected to freeze-thaw (F-T) cycles. The unconfined compressive strength (UCS), F-T cycles, scanning electron microscope (SEM), X-ray diffraction (XRD), and pH tests were conducted to investigate the characteristics of UCS, deformation, pH value, and microscopic mechanism of contaminated soils. The results demonstrated that the UCS of contaminated soils decreased with the increasing F-T cycles and Cu2+ concentration; the strength loss rate increased first and then decreased as the F-T cycles increased. The failure strain rose first and then reduced with the increase of F-T cycles, and increased with the rise of Cu2+ concentration. There was a considerable correlation between UCS, failure strain, and deformation modulus E50. The pH value decreased with the increasing F-T cycles and Cu2+ concentration. The microscopic characteristics indicated that the formation of hydrated calcium silicate and ettringite was the fundamental reason for the enhanced UCS. Besides, heavy metals could be solidified and stabilized by chemical precipitation, physical encapsulation, and ion exchange. The effect of F-T cycles could significantly damage the internal structure of contaminated soils, and the frost heaving force could loosen the soil skeleton structure, leading to the deterioration of the mechanical properties.