120 research outputs found

    YAP Inhibition by Verteporfin Causes Downregulation of Desmosomal Genes and Proteins Leading to the Disintegration of Intercellular Junctions

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    The Hippo-YAP pathway serves as a central signalling hub in epithelial tissue generation and homeostasis. Yes-associated protein (YAP) is an essential downstream transcription cofactor of this pathway, with its activity being negatively regulated by Hippo kinase-mediated phosphorylation, leading to its cytoplasmic translocation or degradation. Our recent study showed phospho-YAP complexes with Desmoglein-3 (Dsg3), the desmosomal cadherin known to be required for junction assembly and cell–cell adhesion. In this study, we show that YAP inhibition by Verteporfin (VP) caused a significant downregulation of desmosomal genes and a remarkable reduction in desmosomal proteins, including the Dsg3/phospho-YAP complex, resulting in attenuation of cell cohesion. We also found the desmosomal genes, along with E-cadherin, were the YAP-TEAD transcriptional targets and Dsg3 regulated key Hippo components, including WWTR1/TAZ, LATS2 and the key desmosomal molecules. Furthermore, Dsg3 and phospho-YAP exhibited coordinated regulation in response to varied cell densities and culture durations. Overexpression of Dsg3 could compensate for VP mediated loss of adhesion components and proper architecture of cell junctions. Thus, our findings suggest that Dsg3 plays a crucial role in the Hippo network and regulates junction configuration via complexing with phospho-YAP

    Evidence for the Desmosomal Cadherin Desmoglein-3 in Regulating YAP and Phospho-YAP in Keratinocyte Responses to Mechanical Forces

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    Desmoglein 3 (Dsg3) plays a crucial role in cell-cell adhesion and tissue integrity. Increasing evidence suggests that Dsg3 acts as a regulator of cellular mechanotransduction, but little is known about its direct role in mechanical force transmission. The present study investigated the impact of cyclic strain and substrate stiffness on Dsg3 expression and its role in mechanotransduction in keratinocytes. A direct comparison was made with E-cadherin, a well-characterized mechanosensor. Exposure of oral and skin keratinocytes to equiaxial cyclic strain promoted changes in the expression and localization of junction assembly proteins. The knockdown of Dsg3 by siRNA blocked strain-induced junctional remodeling of E-cadherin and Myosin IIa. Importantly, the study demonstrated that Dsg3 regulates the expression and localization of yes-associated protein (YAP), a mechanosensory, and an effector of the Hippo pathway. Furthermore, we showed that Dsg3 formed a complex with phospho-YAP and sequestered it to the plasma membrane, while Dsg3 depletion had an impact on both YAP and phospho-YAP in their response to mechanical forces, increasing the sensitivity of keratinocytes to the strain or substrate rigidity-induced nuclear relocation of YAP and phospho-YAP. Plakophilin 1 (PKP1) seemed to be crucial in recruiting the complex containing Dsg3/phospho-YAP to the cell surface since its silencing affected Dsg3 junctional assembly with concomitant loss of phospho-YAP at the cell periphery. Finally, we demonstrated that this Dsg3/YAP pathway has an influence on the expression of YAP1 target genes and cell proliferation. Together, these findings provide evidence of a novel role for Dsg3 in keratinocyte mechanotransduction

    Blockchain enabled data security in vehicular networks

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    Recently, researchers have applied blockchain technology in vehicular networks to take benefit of its security features, such as confidentiality, authenticity, immutability, integrity, and non-repudiation. The resource-intensive nature of the blockchain consensus algorithm makes it a challenge to integrate it with vehicular networks due to the time-sensitive message dissemination requirements. Moreover, most of the researchers have used the Proof-of-Work consensus algorithm, or its variant to add a block to a blockchain, which is a highly resource-intensive process with greater latency. In this paper, we propose a consensus algorithm for vehicular networks named as Vehicular network Based Consensus Algorithm (VBCA) to ensure data security across the network using blockchain that maintains a secured pool of confirmed messages exchanged in the network. The proposed scheme, based on a consortium blockchain, reduces average transaction latency, and increases the number of confirmed transactions in a decentralized manner, without compromising the integrity and security of data. The simulation results show improved performance in terms of confirmed transactions, transaction latency, number of blocks, and block creation time

    Surface engineered mesoporous silica carriers for the controlled delivery of anticancer drug 5-fluorouracil: Computational approach for the drug-carrier interactions using density functional theory

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    Introduction: Drug delivery systems are the topmost priority to increase drug safety and efficacy. In this study, hybrid porous silicates SBA-15 and its derivatives SBA@N and SBA@3N were synthesized and loaded with an anticancer drug, 5-fluorouracil. The drug release was studied in a simulated physiological environment.Method: These materials were characterized for their textural and physio-chemical properties by scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), small-angle X-ray diffraction (SAX), and nitrogen adsorption/desorption techniques. The surface electrostatics of the materials was measured by zeta potential.Results: The drug loading efficiency of the prepared hybrid materials was about 10%. In vitro drug release profiles were obtained in simulated fluids. Slow drug release kinetics was observed for SBA@3N, which released 7.5% of the entrapped drug in simulated intestinal fluid (SIF, pH 7.2) and 33% in simulated body fluid (SBF, pH 7.2) for 72 h. The material SBA@N presented an initial burst release of 13% in simulated intestinal fluid and 32.6% in simulated gastric fluid (SGF, pH 1.2), while about 70% of the drug was released within the next 72 h. Density functional theory (DFT) calculations have also supported the slow drug release from the SBA@3N material. The release mechanism of the drug from the prepared carriers was studied by first-order, second-order, Korsmeyer–Peppas, Hixson–Crowell, and Higuchi kinetic models. The drug release from these carriers follows Fickian diffusion and zero-order kinetics in SGF and SBF, whereas first-order, non-Fickian diffusion, and case-II transport were observed in SIF.Discussion: Based on these findings, the proposed synthesized hybrid materials may be suggested as a potential drug delivery system for anti-cancer drugs such as 5-fluorouracil

    "Who am I? Where am I?" Experiences of married young women in a slum in Islamabad, Pakistan

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    Background: According to the cultural tradition in Pakistan, young women belonging to poor families should marry shortly after menarche. However, existing data show that young people, especially women, are not prepared for sexual life and have poor knowledge about sexuality and reproductive health. Many of the difficulties young women experience are related to beliefs and expectations in the society related to their reproductive roles making them more vulnerable to reproductive ill health. Aim: The study explores the preparedness of young women for married life (communicating with spouse, initiation of sexual activity and child bearing) and ability to negotiate in marriage with spouse on number of children to have and on contraceptive use. Methods: In order to obtain an in-depth understanding of young women’s lives qualitative and quantitative approaches were used. Three qualitative studies using narrative and content analysis were carried out in a slum setting in the outskirts of Islamabad city in Pakistan. Married young women (I), unmarried young women (II) and parents (III) were selected with the help of a community worker. Young married women were interviewed three times at different occasions. Narrative structuring was used to explore how the participants represented their situation. In addition twenty qualitative interviews and three focus group discussions were conducted with young unmarried women (II). Twenty-five parents participated in four gender specific focus group discussions (III). Content analysis was used for analysis of study II and III. For the quantitative study (IV), a subset of 1803 married young women aged 15-24 years was drawn from a nationally representative adolescent and youth survey conducted in Pakistan in 2001-2002 by the Population Council. Regression models were used for analysing the following outcomes: reported agreement with spouse on the number of children to have, current use of contraceptives, intention to use contraceptives in the future and the time elapsed between marriage and the first contraceptive use. Key co-variates of interest were variables that measure the involvement of young women in their marriage as having a say in selection of spouse, mobility outside the household, social role and decision making in their homes. Results: The main theme in all the qualitative studies was ‘socialisation of young women into submissiveness’. For the married young women two themes were identified a) submissive-accepting and b) submissive-victims. The married young women who belonged to the accepting group lived under compromised conditions but described themselves as satisfied with their situation. Women belonging to the victimized group experienced physical and verbal abuse for their inability to cope with the duties of a wife, caretaker of the home and bearer of children. Their situation was compounded by the power dynamics within the household (I). For the unmarried young women the main theme identified was security lies in obedience. The two sub-themes contributing to the main theme were socialisation into submissiveness and transition into adulthood in silence (II). The theme and the sub-themes illustrate the situation of young women in a poor setting in Pakistan. The main theme identified in the study with the parents was ‘Good parents’ strive to raise ‘innocent daughters’. The three sub-themes contributing to the main theme were: a daughter - a responsibility and a burden, social and sexual innocence and parents’ roles in the preparation for marriage. The theme and the sub-themes illustrate how the parents saw themselves as responsible for raising ‘innocent daughters’ and arranging good marriages (III). The quantitative study on the married young women showed that having a say in the selection of spouse at the time of marriage was significantly associated with agreeing with spouse over the number of children to have, intention to use contraceptives and the time between marriage and first contraceptive use. These relationships existed after controlling for education, socioeconomic status, mobility outside of house and decision making in the home (IV). Conclusions: In a culture of silence around sexuality, young women’s socialisation into submissiveness lays the foundation for the lack of control over their future reproductive health (I and II). The parents realised, though, that bringing up daughters for marriage requires not only obedience, but also building confidence and knowledge during their childhood (III). Women who had decision making freedom in their parental home carried this ability with them into marriage in their new home and were better able to negotiate about their fertility (IV). Knowledge about reproductive life could prepare young women better for the future life and give them more control of their fertility. Innovative interventions targeting women need to challenge current societal norms of womanhood to promote the upbringing of confident and knowledgeable young women

    Refinement of arsenic attributable health risks in rural Pakistan using population specific dietary intake values

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    Background: Previous risk assessment studies have often utilised generic consumption or intake values when evaluating ingestion exposure pathways. If these values do not accurately reflect the country or scenario in question, the resulting risk assessment will not provide a meaningful representation of cancer risks in that particular country/scenario. Objectives: This study sought to determine water and food intake parameters for one region in South Asia, rural Pakistan, and assess the role population specific intake parameters play in cancer risk assessment. Methods: A questionnaire was developed to collect data on sociodemographic features and 24-hour water and food consumption patterns from a rural community. The impact of dietary differences on cancer susceptibility linked to arsenic exposure was evaluated by calculating cancer risks using the data collected in the current study against standard water and food intake levels for the USA, Europe and Asia. A probabilistic cancer risk was performed for each set of intake values of this study. Results: Average daily total water intake based on drinking direct plain water and indirect water from food and beverages was found to be 3.5 L day-1 (95% CI: 3.38, 3.57) exceeding the US Environmental Protection Agency’s default (2.5 L day-1) and World Health Organization’s recommended intake value (2 L day-1). Average daily rice intake (469 g day-1) was found to be lower than in India and Bangladesh whereas wheat intake (402 g day−1) was higher than intake reported for USA, Europe and Asian sub-regions. Consequently, arsenic-associated cumulative cancer risks determined for daily water intake was found to be 17 in children of 3-6 years (95% CI: 0.0014, 0.0017), 14 in children of age 6-16 years (95% CI: 0.001, 0.0011) and 6 in adults of 16-67 years (95% CI: 0.0006, 0.0006) in a population size of 10000. This is higher than the risks estimated using the US Environmental Protection Agency and World Health Organization’s default recommended water intake levels. Rice intake data showed early life cumulative cancer risks of 15 in 10000 for children of 3-6 years (95% CI: 0.0012, 0.0015), 14 in children of 6-16 years (95% CI: 0.0011, 0.0014) and later life risk of 8 in adults (95% CI: 0.0008, 0.0008) in a population of 10000. This is lower than cancer risks in countries with higher rice intake and elevated arsenic levels (Bangladesh and India). Cumulative cancer risk from arsenic exposure showed the relative risk contribution from total water to be51%, from rice to be44% and wheat intake 5%. Conclusions: The study demonstrates the need to use population specific dietary information for risk assessment and risk management studies. Probabilistic risk assessment concluded the importance of dietary intake in estimating cancer risk, along with arsenic concentrations in water or food and age of exposed rural population
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