Early tension regulation coupled to surface myomerger is necessary for the primary fusion of C2C12 myoblasts

Here, we study the time-dependent regulation of fluctuation–tension during myogenesis and the role of the fusogen, myomerger. We measure nanometric height fluctuations of the basal membrane of C2C12 cells after triggering differentiation. Fusion of cells increases fluctuation–tension but prefers a transient lowering of tension (at ∼2–24 h). Cells fail to fuse if early tension is continuously enhanced by methyl-β-cyclodextrin (MβCD). Perturbing tension regulation also reduces fusion. During this pre-fusion window, cells that finally differentiate usually display lower tension than other non-fusing cells, validating early tension states to be linked to fate decision. Early tension reduction is accompanied by low but gradually increasing level of the surface myomerger. Locally too, regions with higher myomerger intensity display lower tension. However, this negative correlation is lost in the early phase by MβCD-based cholesterol depletion or later as differentiation progresses. We find that with tension and surface-myomerger’s enrichment under these conditions, myomerger clusters become pronouncedly diffused. We, therefore, propose that low tension aided by clustered surface-myomerger at the early phase is crucial for fusion and can be disrupted by cholesterol-reducing molecules, implying the potential to affect muscle health

Probing the Dynamic Organization of Transcription Compartments and Gene Loci within the Nucleus of Living Cells

AbstractThe three-dimensional organization of nuclear compartments within living cells determines genome function and yet their underlying self-organizing principles are unclear. We visualize in real-time transcriptionally active compartments (TCs) by the transient enrichment of fluorescently-labeled uridine 5′-triphosphate molecules within living cells. These TCs partially colocalize with active RNA-Pol II in the cell nucleus. Fluorescence anisotropy maps of chromatin compaction evidences a more open chromatin structure at the TCs. Using live-cell timelapse imaging, heterogeneity in the dynamic behavior of TCs has been revealed which falls into three distinct classes: subdiffusive, super-diffusive, and normal diffusive behavior. In contrast, the mobility of a candidate gene locus, either in the repressed or activated state, undergoes a differential restricted motion that is coupled to TC movement. Further TC dynamics is directly affected by small molecule chromatin structure modulators and adenosine triphosphate depletion. This heterogeneous behavior in TC dynamics within living cells could provide an interesting paradigm to explore the spatiotemporal dimension to gene transcription control

Effect of heterogeneous substrate adhesivity of follower cells on speed and tension profile of leader cells in primary keratocyte collective cell migration

In single keratocyte motility, membrane tension is reported to be high at cell-fronts and believed to establish front coherence. To understand role of membrane mechanics in collective cell migration, we study membrane height fluctuations in cell sheets from fish scales using interference reflection microscopy (IRM). We report the monolayer to have cells lacking substrate adhesion and show that such ‘non-sticky’ cells can form bridges between leader cells and far-away follower cells. Do such interactions alter motility and membrane mechanics in such leaders? We find non-significant, but reduced speed for leaders with ‘non-sticky’ followers in comparison to other leaders. Cells show high phenotypic variability in their membrane fluctuation tension profiles. On average, this tension is found to be lower at cell fronts than the mid-section. However, leaders with non-sticky followers are more prone to display higher tension at their front and have a negative correlation between cell speed and front-mid tension difference. Thus, we conclude that intracellular tension gradients are heterogeneous in cell sheets and substrate adhesivity of followers can control the coupling of the gradient to cell speed

THE ANTIDEPRESSANT DRUG DOXEPIN: A PROMISING ANTIOXIDANT

ABSTRACTObjective: Oxidative stress contributes to the pathophysiology of exposure to environmental pollutants and to different free radical generatingbiochemical reactions in a human system leading to various types of age-related ailments. An antioxidant is a substance capable of preventingor slowing down oxidation of other molecules. Administration of different natural or synthetic antioxidants can ably lead to prevention andattenuation of such stress-induced biochemical alterations. Best examples of natural antioxidants are plant-derived flavonoids. The presentstudy has been designated to determine antioxidant properties in antidepressant compound doxepin which is structurally similar to flavonoidquercetin.Methods: Antioxidant capacity in doxepin was determined with help of several standard conventional procedures such as phosphomolybdenumassay, Ferric ion and cupric ion reducing power assays, ferrous ion chelating activity assay, hydrogen peroxide, and nitric oxide scavenging activityassays.Results: Doxepin showed a stable rise in its antioxidant activity in a dose-dependent manner as determined by ferric as well as cupric ion reducingcapacity and by phosphomolybdenum assay. An almost identical observation was noted while determining ferrous ion chelating activity. Furthermore,doxepin showed a strong nitric oxide scavenging activity in all the concentrations used in the study while its hydrogen peroxide scavenging activitywas only observed at 500 μg/ml of doxepin.Conclusion: Thus, our study opens up a new vista in search for antioxidants not only from plant sources but also from clinically establishedpharmaceutical compounds that are already in practical use among patients.Keywords: Antioxidant, Antidepressant, Doxepin, Quercetin, Flavanol, Flavonoids

The face behind the Covid-19 mask ??? A comprehensive review

The threat of epidemic outbreaks like SARS-CoV-2 is growing owing to the exponential growth of the global population and the continual increase in human mobility. Personal protection against viral infections was enforced using ambient air filters, face masks, and other respiratory protective equipment. Available facemasks feature considerable variation in efficacy, materials usage and characteristic properties. Despite their widespread use and importance, face masks pose major potential threats due to the uncontrolled manufacture and disposal techniques. Improper solid waste management enables viral propagation and increases the volume of associated biomedical waste at an alarming rate. Polymers used in single-use face masks include a spectrum of chemical constituents: plasticisers and flame retardants leading to health-related issues over time. Despite ample research in this field, the efficacy of personal protective equipment and its impact post-disposal is yet to be explored satisfactorily. The following review assimilates information on the different forms of personal protective equipment currently in use. Proper waste management techniques pertaining to such special wastes have also been discussed. The study features a holistic overview of innovations made in face masks and their corresponding impact on human health and environment. Strategies with SDG3 and SDG12, outlining safe and proper disposal of solid waste, have also been discussed. Furthermore, employing the CFD paradigm, a 3D model of a face mask was created based on fluid flow during breathing techniques. Lastly, the review concludes with possible future advancements and promising research avenues in personal protective equipment

Dystrophy-associated caveolin-3 mutations reveal that caveolae couple IL6/STAT3 signaling with mechanosensing in human muscle cells

Caveolin-3 is the major structural protein of caveolae in muscle. Mutations in the CAV3 gene cause different types of myopathies with altered membrane integrity and repair, expression of muscle proteins, and regulation of signaling pathways. We show here that myotubes from patients bearing the CAV3P28L and R26Q mutations present a dramatic decrease of caveolae at the plasma membrane, resulting in abnormal response to mechanical stress. Mutant myotubes are unable to buffer the increase in membrane tension induced by mechanical stress. This results in impaired regulation of the IL6/STAT3 signaling pathway leading to its constitutive hyperactivation and increased expression of muscle genes. These defects are fully reversed by reassembling functional caveolae through expression ofcaveolin-3. Our study reveals that under mechanical stress the regulation of mechan-oprotection by caveolae is directly coupled with the regulation of IL6/STAT3 signaling inmuscle cells and that this regulation is absent in Cav3-associated dystrophic patients

Victims of Child Sex Trafficking: Are U.S. Pediatricians Ready to Identify, Assess, Treat and Protect Them?

The trafficking of children for commercial sexual exploitation is a gross violation of human rights and a global, public health issue that is rapidly growing and prevalent. Due to the clandestine nature of this crime and the general lack of public knowledge about it, identifying and protecting victims of child sex trafficking (CST) is fraught with challenges. Therefore, it is imperative that healthcare professionals - often the only professionals with whom CST victims come in contact while in captivity - are properly educated and trained on this topic. A literature review reveals there is little knowledge about pediatricians\u27 education and training on identifying and caring for trafficked children. The purpose of this quantitative, exploratory study was to understand if and how well pediatricians in the U.S. are educated/trained on the topic of CST; and the relationship between a pediatrician\u27s education/training and their knowledge of, comfort with and self-perceived barriers in identifying, assessing, treating and reporting a victim of child sex trafficking, leading to specific recommendations for educating and training of pediatricians in the U.S. A survey was distributed to pediatricians across the U.S. with the help of the American Academy of Pediatrics. A total of 127 pediatricians responded. The main findings are as follows: (a) 60% of participants did not receive any education or training on the topic of CST, while about 40% reported only having some during medical school and residency; (b) nearly 70% of our respondents felt only slightly or not at all knowledgeable about various aspects of care for a victim of CST and most cited their lack of training as a barrier to identifying and treating CST victims, underscoring the great need to increase physician education in order to help this CST victims. More education was related with more comfort in assessing and caring for trafficking victims. A vast majority (over 70%) of our study\u27s participants desired more education and training on CST

A national collaboration on reducing tobacco use in the behavioral health population in the United States

Background and challenges to implementation One of the greatest disparities is high smoking prevalence in the behavioral health (BH) population - individuals with mental illness and/or substance use disorders. Despite progress in lowering the rate of tobacco use overall, smoking prevalence in the BH population in the US is 34%, more than double the national average. The BH population accounts for 240,000 of the 540,000 annual deaths from smoking. BH sufferers die 10 to 25 years earlier than the general population, mainly from smoking-related diseases. Traditionally, health professionals, governmental agencies and advocacy groups have not identified BH sufferers as a priority population for promoting smoking cessation. Intervention or response The American Cancer Society (ACS) and the Smoking Cessation Leadership Center (SCLC) at the University of California, San Francisco, launched a multisectoral partnership in 2016 at a summit attended by 16 national health professional groups, federal government agencies, civil society groups and individual experts in tobacco control and BH. The participants established a new initiative to promote prevention and cessation in the BH population through networking, education and clinical guidance. ACS and SCLC lead this collaboration and are developing the necessary infrastructure to sustain it. Every participant commits to taking specific actions to enhance collective communications and educate and guide their constituencies of professions and consumers. Results and lessons learnt The alliance of organizations reviewed smoking prevalence and health impact on the BH population, and best practices for reducing tobacco use. It then adopted the ambitious goal to reduce smoking prevalence in the behavioral health population in the US from 34% to 30% by the year 2020. Conclusions and key recommendations 22 million US smokers suffer from BH conditions. Reducing their prevalence to 30%, or 19.5 million smokers, would result in 2.5 million fewer smokers, saving over a million lives. This unique collaboration endeavors to significantly reduce smoking prevalence and has the potential to be replicated globally

Tobacco-free generation campus initiative: a program to increase the number of tobacco-free colleges in the United States

Background and challenges to implementation There are 20 million college and university students in the United States. More than 1 million of these young adults are projected to die from cigarette smoking. Progress has been made in protecting campus populations against tobacco. There are now 1,913 smoke-free college and university campuses, of which 1,611 are fully tobacco-free. Yet, there are 4,500 higher education institutions in the US, and many still lack comprehensive smoke- and/or tobacco-free policies due to inertia, competing needs and opposition from tobacco supporters and those expressing libertarian objections. Intervention or response In response, the American Cancer Society launched the Tobacco-Free Generation Campus Initiative (TFGCI) in 2016, which targets students, faculty, staff and visitors at a variety of academic institutions - from small community colleges to large research universities - across the country. TFGCI provides financial support to colleges and universities to pursue campaigns to adopt and implement comprehensive tobacco-free policies and is supported by the CVS Health Foundation. Grantees also receive technical assistance and materials. TFGCI advises campus leaders and students on advocacy best practices, policy adoption, implementation and enforcement issues, cessation strategies and communications, and includes an evaluation component. Results and lessons learnt Seven of the 20 institutions in Cohort 1 approved tobacco-free policies during the first year, a high level of success. Each institution confronted unique challenges, including opposition from skeptics - sometimes including the institution's leadership - but most effectively advanced knowledge and built support. Cohort 2 commences work in Fall 2017, and includes an additional 42 institutions. TFGCI will eventually support 125 institutions. Conclusions and key recommendations Cohorts 1 and 2 cover 930,000 students, plus many faculty, staff and visitors. TFGCI has demonstrated that, with sufficient resources and application of best practices, these campaigns can succeed. Recommendations include the utilization of evidence-based resources, effective communication and education, and application of best practices in all campus policy campaigns

Estimate of entropy generation rate can spatiotemporally resolve the active nature of cell flickering

We use the short-time inference scheme (Manikandan, Gupta and Krishnamurthy, Phys. Rev. Lett. 124, 120603, 2020), obtained within the framework of stochastic thermodynamics, to infer a lower-bound to entropy generation rate from flickering data generated by Interference Reflection Microscopy of HeLA cells. We can clearly distinguish active cell membranes from their ATP depleted selves and even spatio-temporally resolve activity down to the scale of about one $\mu$m. Our estimate of activity is model--independent.Comment: 11 pages 6 figure