Actin Remodeling in Regulated Exocytosis: Toward a Mesoscopic View

Publication date: Available online 11 May 2018
Source:Trends in Cell Biology
Author(s): Pin Li, Adekunle T. Bademosi, Jincai Luo, Frederic A. Meunier
Cellular communication relies on fusion of secretory vesicles with the plasma membrane, following dynamic events that change the micro- and nanoscale environment of the approaching vesicles in the vicinity of docking sites. Visualization of fine cortical actin network structures and their interactions with vesicle and plasma membrane has recently been facilitated by the development of new imaging technologies. Consequently, a greater understanding is emerging of the role of the cortical actin network on controlling secretory vesicles as they undergo docking, priming, and fusion in exocytic hot spots. In this review, we propose a mechanistic framework underpinning the mesoscopic properties of the cortical actin and discuss how molecular coupling of these pleiotropic effects orchestrate every single step of regulated exocytosis.



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Metabolic Hallmarks of Metastasis Formation

Publication date: Available online 7 May 2018
Source:Trends in Cell Biology
Author(s): Ilaria Elia, Ginevra Doglioni, Sarah-Maria Fendt
Metastasis to distant organs is a predictor of poor prognosis. Therefore, it is of paramount importance to understand the mechanisms that impinge on the different steps of the metastatic cascade. Recent work has revealed that particular metabolic pathways are rewired in cancer cells to support their transition through the metastatic cascade, resulting in the formation of secondary tumors in distant organs. Indeed, metabolic rewiring induces signaling pathways during initial cancer invasion, circulating cancer cells depend on enhanced antioxidant defenses, and cancer cells colonizing a distant organ require increased ATP production. Moreover, the local environment of the metastatic niche dictates the metabolic pathways secondary tumors rely on. Here we describe mechanisms of metabolic rewiring associated with distinct steps of metastasis formation.



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Regulation and Roles of Autophagy at Synapses

Publication date: Available online 3 May 2018
Source:Trends in Cell Biology
Author(s): Vassiliki Nikoletopoulou, Nektarios Tavernarakis
Genetic studies have demonstrated that conditional ablation of core autophagy genes in the neural lineage leads to progressive neurodegeneration, indicating that this catabolic pathway is indispensable for neuronal maintenance. However, accumulating evidence also indicates that autophagy is not merely a housekeeping process. Instead, autophagy may be dynamically regulated in different neuronal compartments and dictate the turnover of selected cargo in a time- and space-dependent manner and thus contribute to specialized neuronal functions. Here, we review the mechanisms regulating autophagy in neurons and discuss recent findings on the role of autophagy in synaptic morphology and function. Moreover, we discuss relevant questions that remain open and highlight forthcoming issues in the field of neuronal autophagy.



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Synergistic Mechano-Chemical Sensing by Vascular Cilia

Publication date: Available online 2 May 2018
Source:Trends in Cell Biology
Author(s): Gautier Follain, Jacky G. Goetz
Endothelial cells can sense and respond to blood flow forces and signals, but the exact mechanisms employed remain poorly understood. A recent study describes how low-flow forces are sensed by primary cilia during development of the retinal vasculature, which sensitizes endothelial cells to BMP signaling.



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Editorial Board and Contents

Publication date: May 2018
Source:Trends in Cell Biology, Volume 28, Issue 5





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Metabolic signature of squamous cell carcinoma of the head and neck: Consequences of TP53 mutation and therapeutic perspectives

Publication date: August 2018
Source:Oral Oncology, Volume 83
Author(s): Mark D. Wilkie, Andrew S. Lau, Nikolina Vlatkovic, Terence M. Jones, Mark T. Boyd
There is a pressing need to identify ways of sensitising squamous cell carcinomas of the head and neck (SCCHN) to the effects of current treatments, both from oncological and functional perspectives. Alteration to cellular metabolism is now widely considered a hallmark of the cancer phenotype; presents a potentially attractive therapeutic target in this regard; and as such has received renewed research interest in recent years. However, whilst metabolic disruption may occur to some degree in all tumours, there is undoubtedly heterogeneity and detailed study of individual tumour types is paramount if effective therapeutic strategies targeting metabolism are to be developed and effectively deployed. In this review we outline current understanding of altered tumour metabolism and how these adaptations promote tumorigenesis generally. We relate this specifically to SCCHN by focusing on several recent key studies specific to SCCHN, and by discussing the role TP53 mutation may play in this metabolic switch, given the fundamental role of this oncogenic event in SCCHN tumorigenesis. Finally, we also offer insight into the potential therapeutic implications this may have in the clinical setting and make recommendations for future study.



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Comparative study of Gram-negative bacteria response to solar photocatalytic inactivation

Abstract

Solar photocatalytic inactivation of Gram-negative bacteria with immobilized TiO₂-P25 in a fixed-bed reactor was modeled with simplified kinetic equations. The kinetic parameters are the following: the photocatalytic inactivation coefficient (k_d,QUV), the initial bacterial reduction rate (A) in the contact with the disinfecting agent, and the threshold level of damage (n) were determined to report the effect of Q_UV/TiO₂-P25 on bacterial cultivability and viability and to compare the response of bacterial strains to photocatalytic treatment. In addition, the integration of the reactivation coefficient (C_r) in the photocatalytic inactivation equation allowed evaluating the ability of bacterial reactivation after photocatalytic stress. Results showed different responses of the bacteria strains to photocatalytic stress and the ability of certain bacterial strains such as Escherichia coli ATCC25922 and Pseudomonas aeruginosa ATCC4114 to resuscitate after photocatalytic treatment.

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