Current topics in membranes最新文献

Sphingolipids are unique among cellular lipids inasmuch as their biosynthesis is compartmentalized between the endoplasmic reticulum (ER) and the Golgi apparatus. This compartmentalization was first recognized about thirty years ago, and the current review not only updates studies on the compartmentalization of sphingolipid biosynthesis, but also discusses the ramifications of this feature for our understanding of how the pathway could have evolved. Thus, we augment some of our recent studies by inclusion of two further molecular pathways that need to be considered when analyzing the evolutionary requirements for generation of sphingolipids, namely contact sites between the ER and the Golgi apparatus, and the mechanism(s) of vesicular transport between these two organelles. Along with evolution of the individual enzymes of the pathway, their subcellular localization, and the supply of essential metabolites via the anteome, it becomes apparent that current models to describe evolution of the sphingolipid biosynthetic pathway may need substantial refinement.

Lysosomes are more than just cellular recycling bins; they play a crucial role in regulating key cellular functions. Proper lysosomal function is essential for growth pathway regulation, cell proliferation, and metabolic homeostasis. Impaired lysosomal function is associated with lipid storage disorders and neurodegenerative diseases. Lysosomes form extensive and dynamic close contacts with the membranes of other organelles, including the endoplasmic reticulum, mitochondria, peroxisomes, and lipid droplets. These membrane contacts sites (MCSs) are vital for many lysosomal functions. In this chapter, we will explore lysosomal MCSs focusing on the machinery that mediates these contacts, how they are regulated, and their functional implications on physiology and pathology.

This chapter focuses on the interplay between Leishmania parasites and their host, particularly on Leishmania RNA virus (LRVs) and extracellular vesicles (EVs) in modulating host-pathogen interactions. Leishmania EVs have been shown to facilitate gene transfer, including drug-resistance genes, enhancing the parasites' survival and resistance to antileishmanial therapeutics. These EVs also play a significant role in host immune modulation by altering cytokine production in macrophages and promoting an anti-inflammatory environment that favours parasitic persistence. The presence of virulence factors such as GP63 within these EVs further underscores their role in the parasite's immunopathogenesis. Over the last few decades, LRVs have been established as drivers of the severity and persistence of leishmaniasis by exacerbating inflammatory responses and potentially influencing treatment outcomes. This chapter discusses the evolutionary origins and classification of these viruses, and explores their role in parasitic pathogenicity, highlighting their ubiquity across protozoan parasites and their impact on disease progression.

Toxoplasma gondii, the causative agent of toxoplasmosis, is widely distributed. This protozoan parasite is one of the best adapted, being able to infect innumerous species of animals and different types of cells. This chapter reviews current literature on extracellular vesicles secreted by T. gondii and by its hosts. The topics describe the life cycle and transmission (1); toxoplasmosis epidemiology (2); laboratorial diagnosis approach (3); The T. gondii interaction with extracellular vesicles and miRNAs (4); and the perspectives on T. gondii infection. Each topic emphases the host immune responses to the parasite antigens and the interaction with the extracellular vesicles and miRNAs.

The genomic sequences attributed to the coat protein play a pivotal role in the evolutionary trajectory of plant viruses. The coat protein region, particularly scrutinized in the genus of Ilarvirus phylogroups, actively shapes the regional and host-specific dispersion. Within this chapter, assorted insights pertaining to the roles undertaken by coat proteins of frequently encountered Ilarviruses in their evolutionary processes are consolidated. Nonetheless, it is discerned that the availability of genomic data for RNA1 and RNA2 remains markedly limited, impeding the provision of lucid elucidations in this domain. Hence, to comprehensively delineate the evolution of Ilarviruses, a requisite exists for supplementary nucleotide sequence data, with a particular emphasis on taxa that have received lesser attention in research endeavors.

Extracellular vesicles (EVs) are produced, secreted, and targeted by most human cells, including cells that compose nervous system tissues. EVs carry several types of biomolecules, such as lipids, proteins and microRNA, and can function as signaling agents in physiological and pathological processes. In this chapter, we will focus on EVs and their cargo secreted by brain cells, especially neurons and glia, and how these aspects are affected in pathological conditions. The chapter covers neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis, as well as several psychiatric disorders, namely schizophrenia, autism spectrum disorder and major depressive disorder. This chapter also addresses other types of neurological dysfunctions, epilepsy and traumatic brain injury. EVs can cross the blood brain barrier, and thus brain EVs may be detected in more accessible peripheral tissue, such as circulating blood. Alterations in EV composition and contents can therefore impart valuable clues into the molecular etiology of these disorders, and serve biomarkers regarding disease prevalence, progression and treatment. EVs can also be used to carry drugs and biomolecules into brain tissue, considered as a promising drug delivery agent for neurological diseases. Therefore, although this area of research is still in its early development, it offers great potential in further elucidating and in treating neurological disorders.

Sleep is vital in preserving mental and physical well-being by aiding bodily recovery, strengthening the immune system, and regulating hormones. It enhances memory, concentration, and mood regulation, reducing stress and anxiety. Sleep deprivation, a common phenomenon affecting approximately 20% of adults, decreases performance, alertness, and health integrity. Furthermore, it triggers physiological changes, including increased stress hormone levels, leading to various disorders such as hyperglycemia and hypertension. Recent research explores the role of extracellular vesicles (EVs) in sleep-related conditions. EVs, released by cells, play vital roles in intercellular communication and biomarker potential. Studies indicate that sleep deprivation influences EV release, impacting cancer progression, endothelial inflammation, and thrombosis risk. Understanding these mechanisms offers insights into therapeutic interventions. Thus, multidisciplinary approaches are crucial to unraveling the complex interactions between sleep, EVs, and health, providing direction for effective prevention and treatment approaches for sleep disorders and related conditions.

Trypanosomes are protozoan parasites responsible for human diseases such as Chagas disease, African trypanosomiasis, and leishmaniasis. These organisms' growth in various environments and exhibit multiple morphological stages, while adapting their surface components. They acquire and release materials extensively to get nutrients and manage interactions with the extracellular environment. They acquire and utilize proteins, lipids, and carbohydrates for growth via using membrane transport and endocytosis. Endocytosis takes place through distinct membrane areas known as the flagellar pocket and cytostome, depending on the parasite species and its developmental stage. Some forms establish a complex endocytic system to either store or break down the absorbed materials. In contrast, membrane transport facilitates the uptake of small molecules like amino acids, carbohydrates, and iron via particular receptors on the plasma membrane. Concurrently, these parasites secrete various molecules such as proteins, enzymes, nucleic acids, and glycoconjugates either in soluble form or enclosed in extracellular vesicles, which significantly contribute to their parasitic behavior. These activities require exocytosis through a secretory pathway in certain membrane domains such as the flagellum, flagellar pocket, and plasma membrane, which are controlled at various developmental stages. The main features of the endocytic and exocytic mechanisms, as well as the organelles involved, are discussed in this chapter along with their connection to the formation of exosomes and extracellular vesicles in the Tritryp species.

Extracellular vesicles (EVs) are membrane-bound particles released by cells that play a significant role in intercellular communication. They can be obtained from a variety of sources, including conditioned culture medium, blood and urine. In this chapter we detail the methods for EV isolation and characterization. Isolating and characterizing EVs is essential for understanding their functions in physiological and pathological processes. Advances in isolation and characterization techniques provide opportunities for deeper research into EV biology and its potential applications in diagnostics and therapeutics.