The biology of the heat shock response in parasites

The heat shock response is a general homeostatic mechanism that protects cells and the entire organism from the deleterious effects of environmental stress. It has been shown that heat shock proteins play major roles in many cellular processes and have a unique role in several areas of cell biology, from chronic degenerative diseases to immunology and from cancer research to interactions between host and parasite. In this review, Bruno Maresca and Luisella Carratu deal with some of the unique characteristics of the heat shock response in parasitic organisms.     

Options for imaging cellular therapeutics in vivo: a multi-stakeholder perspective

Cell-based therapies have been making great advances toward clinical reality. Despite the increase in trial activity, few therapies have successfully navigated late-phase clinical trials and received market authorization. One possible explanation for this is that additional tools and technologies to enable their development have only recently become available. To support the safety evaluation of cell therapies, the Health and Environmental Sciences Institute Cell Therapy—Tracking, Circulation and Safety Committee, a multisector collaborative committee, polled the attendees of the 2017 International Society for Cell & Gene Therapy conference in London, UK, to understand the gaps and needs that cell therapy developers have encountered regarding safety evaluations in vivo. The goal of the survey was to collect information to inform stakeholders of areas of interest that can help ensure the safe use of cellular therapeutics in the clinic. This review is a response to the cellular imaging interests of those respondents. The authors offer a brief overview of available technologies and then highlight the areas of interest from the survey by describing how imaging technologies can meet those needs. The areas of interest include imaging of cells over time, sensitivity of imaging modalities, ability to quantify cells, imaging cellular survival and differentiation and safety concerns around adding imaging agents to cellular therapy protocols. The Health and Environmental Sciences Institute Cell Therapy—Tracking, Circulation and Safety Committee believes that the ability to understand therapeutic cell fate is vital for determining and understanding cell therapy efficacy and safety and offers this review to aid in those needs. An aim of this article is to share the available imaging technologies with the cell therapy community to demonstrate how these technologies can accomplish unmet needs throughout the translational process and strengthen the understanding of cellular therapeutics.     

The 1st EMBO workshop on PVC bacteria—Planctomycetes–Verrucomicrobia–Chlamydiae superphylum: Exceptions to the bacterial definition?

The PVC superphylum is a phylogenetically supported collection of various related bacterial phyla that comprise unusual characteristics and traits. The ‘PVC’ abbreviation derives from Planctomycetes, Verrucomicrobia and Chlamydiae as members of this superphylum, while additional bacterial phyla are related. There has recently been increasing and exciting interest in the cell biology, physiology and ecology of members of this superphylum, including evolutionary implications of the complex cell organization of some species. It is timely that international researchers in the PVC superphylum field met to discuss these developments. The first meeting entirely dedicated to those bacteria, the EMBO workshop “PVC superphylum: Exceptions to the bacterial definition” was held at the Heidelberg University to catalyze the formation of a vital scientific community supporting PVC-bacterial research. More than 45 investigators from more than 20 countries (PIs, senior scientists and students) attended the meeting and produced a great starting point for future collaborative research. This Special Issue will focus on the EMBO-PVC meeting. This Perspective briefly summarizes the history of PVC-research, focusing on the key findings and provides a brief summary of the meeting with a focus on the major questions that arose during discussion and that might influence the research in the years to come.     

Protein interactions with surfaces: Computational approaches and repellency

Study of protein adsorption to solid surfaces continues to be substantial because of its role in cellular responses to biomaterials, interest in molecular aspects such as conformation and orientation, new methods for making protein repellent surfaces, and new application areas such as nanoparticles and microfluidics. This brief review is based only on very recent articles of particular interest to the authors, who each have worked in this area for some time. Simulations of protein interactions with surfaces and protein repellent surfaces are the only subtopics reviewed here.     

Current challenges in the manufacture of clinical-grade autologous whole cell vaccines for hematological malignancies

Autologous whole cell vaccines use a patient's own tumor cells as a source of antigen to elicit an anti-tumor immune response in vivo. Recently, the authors conducted a systematic review of clinical trials employing these products in hematological cancers that showed a favorable safety profile and trend toward efficacy. However, it was noted that manufacturing challenges limit both the efficacy and clinical implementation of these vaccine products. In the current literature review, the authors sought to define the issues surrounding the manufacture of autologous whole cell products for hematological cancers. The authors describe key factors, including the acquisition, culture, cryopreservation and transduction of malignant cells, that require optimization for further advancement of the field. Furthermore, the authors provide a summary of pre-clinical work that informs how the identified challenges may be overcome. The authors also highlight areas in which future basic research would be of benefit to the field. The goal of this review is to provide a roadmap for investigators seeking to advance the field of autologous cell vaccines as it applies to hematological malignancies.     

Molecular mechanisms of fluoride toxicity

Halfway through the twentieth century, fluoride piqued the interest of toxicologists due to its deleterious effects at high concentrations in human populations suffering from fluorosis and in in vivo experimental models. Until the 1990s, the toxicity of fluoride was largely ignored due to its “good reputation” for preventing caries via topical application and in dental toothpastes. However, in the last decade, interest in its undesirable effects has resurfaced due to the awareness that this element interacts with cellular systems even at low doses. In recent years, several investigations demonstrated that fluoride can induce oxidative stress and modulate intracellular redox homeostasis, lipid peroxidation and protein carbonyl content, as well as alter gene expression and cause apoptosis. Genes modulated by fluoride include those related to the stress response, metabolic enzymes, the cell cycle, cell–cell communications and signal transduction.The primary purpose of this review is to examine recent findings from our group and others that focus on the molecular mechanisms of the action of inorganic fluoride in several cellular processes with respect to potential physiological and toxicological implications. This review presents an overview of the current research on the molecular aspects of fluoride exposure with emphasis on biological targets and their possible mechanisms of involvement in fluoride cytotoxicity. The goal of this review is to enhance understanding of the mechanisms by which fluoride affects cells, with an emphasis on tissue-specific events in humans.     

Toxicity of Amyloid β Peptide: Tales of Calcium,Mitochondria, and Oxidative Stress

Alzheimer's disease (AD) is characterized by the accumulation of amyloid-beta (Abeta) peptides. Although the disease undoubtedly reflects the interaction of complex multifactorial processes, Abeta itself is toxic to neurons in vitro and the load of Abeta in vivo correlates well with the degree of cognitive impairment. There has therefore been considerable interest in the mechanism(s) of Abeta neurotoxicity. We here review the basic biology of Abeta processing and consider some of the major areas of focus of this research. It is clear that both AD and Abeta toxicity are characterized by oxidative stress, alterations in the activity of enzymes of intermediary metabolism, and mitochondrial dysfunction, especially impaired activity of cytochrome c oxidase. Studies in vitro also show alterations in cellular calcium signaling. We consider the mechanisms proposed to mediate cell injury and explore evidence to indicate which of these many changes in function are primary and which secondary.     

The aryl hydrocarbon receptor, more than a xenobiotic-interacting protein

The aryl hydrocarbon (dioxin) receptor (AhR) has been studied for several decades largely because of its critical role in xenobiotic-induced toxicity and carcinogenesis. Albeit this is a major issue in basic and clinical research, an increasing number of investigators are turning their efforts to try to understand the physiology of the AhR under normal cellular conditions. This is an exciting area that covers cell proliferation and differentiation, endogenous mechanisms of activation, gene regulation, tumor development and cell motility and migration, among others. In this review, we will attempt to summarize the studies supporting the implication of the AhR in those endogenous cellular processes.     

Relationship between cancer and psychology: an updated history

The mechanism and formation of cancer have always been topics of interest for scientists, even for doctors in ancient times. Nowadays a great role for cancer is played by psychological stress which promotes relevant changes in neuronal activity and gene regulations across the different brain areas. It has been reported by many authors that stress can have an important role in the immune system and may be relevant in the formation of cancer. Our observations, in accordance with other research studies, confirm the importance of the influence of depression, linked to neuroendocrine stress, on the enhancement of cancer pathogenesis by inhibiting anti-tumor immune responses. In this article we review the past and present history of the relationship between cancer and psychology.     

The ubiquitin-proteasome system in cardiac physiology and pathology

The ubiquitin-proteasome system (UPS) is the major nonlysosomal pathway for intracellular protein degradation, generally requiring a covalent linkage of one or more chains of polyubiquitins to the protein intended for degradation. It has become clear that the UPS plays major roles in regulating many cellular processes, including the cell cycle, immune responses, apoptosis, cell signaling, and protein turnover under normal and pathological conditions, as well as in protein quality control by removal of damaged, oxidized, and/or misfolded proteins. This review will present an overview of the structure, biochemistry, and physiology of the UPS with emphasis on its role in the heart, if known. In addition, evidence will be presented supporting the role of certain muscle-specific ubiquitin protein ligases, key regulatory components of the UPS, in regulation of sarcomere protein turnover and cardiomyocyte size and how this might play a role in induction of the hypertrophic phenotype. Moreover, this review will present the evidence suggesting that proteasomal dysfunction may play a role in cardiac pathologies such as myocardial ischemia, congestive heart failure, and myofilament-related and idiopathic-dilated cardiomyopathies, as well as cardiomyocyte loss in the aging heart. Finally, certain pitfalls of proteasome studies will be described with the intent of providing investigators with enough information to avoid these problems. This review should provide current investigators in the field with an up-to-date analysis of the literature and at the same time provide an impetus for new investigators to enter this important and rapidly changing area of research.     

Redox regulation of cellular stress response in neurodegenerative disorders

There is increasing evidence that reactive oxygen species (ROS) are not only toxic but play an important role in cellular signaling and in the regulation of gene expression. A number of biochemical and physiologic stimuli, such as perturbation in redox status, expression of misfolded proteins, altered glyc(osyl)ation and glucose deprivation, overloading of products of polyunsaturated fatty acid peroxidation (Hydroxynonenals, HNE) or cholesterol oxidation and decomposition, can disrupt redox homeostasis, impose stress and subsequently lead to accumulation of unfolded or misfolded proteins in brain cells. Alzheimer's (AD), Parkinson's (PD), Huntington's disease (HD), Amyothrophic lateral sclerosis (ALS) and Friedreich ataxia (FRDA) are major neurological disorders associated with production of abnormal proteins and, as such, belong to the so called "protein conformational diseases". The Central Nervous System has evolved highly specific signaling pathways called the unfolded protein response to cope with the accumulation of unfolded or misfolded proteins. Recent discoveries of the mechanisms of cellular stress signaling have led to major new insights into the diverse processes that are regulated by cellular stress response. Thus, the pathogenic dysfunctional aggregation of proteins in non-native conformations is associated with metabolic derangements and excessive production of ROS. The brain response to detect and control metabolic or oxidative stress is accomplished by a complex network of "longevity assurance processes" integrated to the expression of genes termed vitagenes. Heat shock proteins are a highly conserved system responsible for the preservation and repair of correct protein conformation. Heme oxygenase-1, a inducible and redox-regulated enzyme, is currently considered as having an important role in cellular antioxidant defense. A neuroprotective effect, due to its heme degrading activity, and tissue-specific antioxidant effects due to its products CO and biliverdin, this latter being further reduced by biliverdin reductase in bilirubin is an emerging concept. There is a current interest in dietary compounds that can inhibit, retard or reverse the multi-stage pathophysiology of Alzheimer disease, with a chronic inflammatory response, brain injury and beta-amyloid associated pathology. Curcumin and ferulic acid, two powerful antioxidants, the first from the curry spice turmeric and the second a major constituent of fruit and vegetables, have emerged as strong inducers of the heat shock response. Food supplementation with curcumin and ferulic acid is considered a nutritional approach to reduce oxidative damage and amyloid pathology in Alzheimer disease. This review summarizes the complex regulation of cellular stress signaling and its relevance to human physiology and disease.     

Interactions of heat shock protein 47 with collagen and the stress response: an unconventional chaperone model?

Heat shock proteins (HSPs) are upregulated and manifested upon cellular stress and possess chaperoning functions. HSP47 is an endoplasmic reticulum (ER)-resident, collagen-specific chaperone and plays a key role in collagen biosynthesis and its structural assembly. The collagen scaffold is a primary structural target of recent interest due to its applications in tissue engineering and drug delivery and in treatment of clinical disorders. This review highlights the fundamental aspects of HSPs in protein folding and quality control, in the elicitation of a stress response in connective tissue and in the characterization of HSP47 in collagen folding and assembly. The significant features of HSP47 which are distinct in its cellular capabilities are discussed. We propose that targeting the stress response is a key factor in identifying connective tissue biomarkers. We also address the issues and strategies involved in the stress response of connective tissue diseases. In conclusion, we describe the prospects of collagen biochemistry in correlation to the science of HSPs.     

Current knowledge about the functional roles of phosphorylative changes of membrane proteins in normal and diseased red cells

With the advent of proteomic techniques the number of known post-translational modifications (PTMs) affecting red cell membrane proteins is rapidly growing but the understanding of their role under physiological and pathological conditions is incompletely established. The wide range of hereditary diseases affecting different red cell membrane functions and the membrane modifications induced by malaria parasite intracellular growth represent a unique opportunity to study PTMs in response to variable cellular stresses. In the present review, some of the major areas of interest in red cell membrane research have been considered as modifications of erythrocyte deformability and maintenance of the surface area, membrane transport alterations, and removal of diseased and senescent red cells. In all mentioned research areas the functional roles of PTMs are prevalently restricted to the phosphorylative changes of the more abundant membrane proteins. The insufficient information about the PTMs occurring in a large majority of the red membrane proteins and the general lack of mass spectrometry data evidence the need of new comprehensive, proteomic approaches to improve the understanding of the red cell membrane physiology.     

Locating macromolecules and determining structures inside bacterial cells using electron cryotomography

Electron cryotomography (cryo-ET) is an imaging technique uniquely suited to the study of bacterial ultrastructure and cell biology. Recent years have seen a surge in structural and cell biology research on bacteria using cryo-ET. This research has driven major technical developments in the field, with applications emerging to address a wide range of biological questions. In this review, we explore the diversity of cryo-ET approaches used for structural and cellular microbiology, with a focus on in situ localization and structure determination of macromolecules. The first section describes strategies employed to locate target macromolecules within large cellular volumes. Next, we explore methods to study thick specimens by sample thinning. Finally, we review examples of macromolecular structure determination in a cellular context using cryo-ET. The examples outlined serve as powerful demonstrations of how the cellular location, structure, and function of any bacterial macromolecule of interest can be investigated using cryo-ET.     

Fishing for genes influencing vertebrate behavior: zebrafish making headway

The zebrafish (Danio rerio) has been a favorite model of developmental biologists and geneticists, but only recently have investigators begun to appreciate its usefulness in behavior genetics. Papers focusing on the behavior or brain function of this species were once extremely rare, but during the past decade rapid growth has taken place. Despite the increased interest, however, the number of studies devoted to the analysis of the behavior of this species is still orders of magnitude less than those conducted on more traditional laboratory subjects including the rat and the mouse. The authors review selected literature and demonstrate that zebrafish is an excellent subject for behavior genetics research, especially in the area of forward genetics (mutagenesis).     

The major anoxic stress response protein p34 is a distinct lactate dehydrogenase

Anoxic stress is a common physiological stress, but one with unusual and significant consequences. Anoxic stress results in efficient induction of gene amplification and also plays a controlling role in the production of angiogenesis factor by macrophages. Within tumor masses, cancer cells continue to proliferate under oxygen tensions substantially lower than seen in normal tissues. The molecular basis of the anoxic stress response has not been well characterized. The major anoxic stress protein in subconfluent cell cultures is a 34-kilodalton polypeptide which has been variously reported to be either a new isozyme of lactate dehydrogenase (LDH) or the conventional muscle-type lactate dehydrogenase. This protein is of particular interest since it is also found expressed at high levels in many human cancers and has been demonstrated to be an effective serum cancer marker. We have developed an affinity chromatography procedure for purification of the anoxic stress protein p34 which effectively separates this protein from LDH-5 as well as other standard LDH isozymes. Anoxic stress protein p34 was found to specifically interact with flavins and the cellular alarmone guanosine(5')tetraphospho(5')guanosine, and also to interact with certain nucleic acids. The properties of this protein suggest that its overall role in the anoxic stress response may be in the coordination of a number of cellular systems.     

High-throughput screening assays for the identification of chemical probes

High-throughput screening (HTS) assays enable the testing of large numbers of chemical substances for activity in diverse areas of biology. The biological responses measured in HTS assays span isolated biochemical systems containing purified receptors or enzymes to signal transduction pathways and complex networks functioning in cellular environments. This Review addresses factors that need to be considered when implementing assays for HTS and is aimed particularly at investigators new to this field. We discuss assay design strategies, the major detection technologies and examples of HTS assays for common target classes, cellular pathways and simple cellular phenotypes. We conclude with special considerations for configuring sensitive, robust, informative and economically feasible HTS assays.