ESCRTs are everywhere

From bench to bedside: the research status and application opportunity of extracellular vesicles and their engineering strategies in the treatment of skin defects

Engineered extracellular vesicles (EVs), which are EVs modified to enhance certain biological properties, offer a promising therapeutic strategy for the treatment of skin defects. Conventional nanomaterials often encounter clinical translation challenges due to potential toxicity and limited targeting. Engineered EVs, utilizing inherent biocompatibility and effective physiological barrier traversal, can ameliorate the limitations of conventional EV therapies to some extent, including detection, isolation, purification, and therapeutic validation. Recent advances in EV engineering, such as genetic modification of production cells to control cargo, surface engineering for targeted delivery, and pre-treatment of parental cells to optimize production and bioactivity, have improved therapeutic efficacy in laboratory studies through enhanced targeting, prolonged retention time, and increased yield. Many studies have suggested the potential ability of engineered EVs to treat a variety of skin defects, including diabetic wounds, burns, and hypertrophic scars, providing a promising avenue for their clinical translation in this area. This paper reviews the therapeutic potential of engineered EVs in skin regeneration, highlighting their role in promoting cell migration and angiogenesis, modulating inflammation and reducing scar formation during wound healing. In addition, given the investment in this rapidly evolving field and the growing clinical trial activity, this review also explores recent global advances and provides an outlook on future application opportunities for EVs in the treatment of skin defects.

Extracellular Vesicles in the Crosstalk of Autophagy and Apoptosis: A Role for Lipid Rafts

Autophagy and apoptosis are two essential mechanisms regulating cell fate. Although distinct, their signaling pathways are closely interconnected through various crosstalk mechanisms. Lipid rafts are described to act as both physical and functional platforms during the early stages of autophagic and apoptotic processes. Only recently has a role for lipid raft-associated molecules in regulating EV biogenesis and release begun to emerge. In particular, lipids of EV membranes are essential components in conferring stability to these vesicles in different extracellular environments and/or to facilitate binding or uptake into recipient cells. In this review we highlight these aspects, focusing on the role of lipid molecules during apoptosis and secretory autophagy pathways. We describe the molecular machinery that connects autophagy and apoptosis with vesicular trafficking and lipid metabolism during the release of EVs, and how their alterations contribute to the development of various diseases, including autoimmune disorders and cancer. Overall, these findings emphasize the complexity of autophagy/apoptosis crosstalk and its key role in cellular dynamics, supporting the role of lipid rafts as new therapeutic targets.

Autophagy Dysfunction and Neurodegeneration: Where Does It Go Wrong?

An infamous hallmark of neurodegenerative diseases is the accumulation of misfolded or unfolded proteins forming inclusions in the brain. The accumulation of these abnormal structures is a mysterious one, given that cells devote significant resources to integrate complementary pathways to ensure proteome integrity and proper protein folding. Aberrantly folded protein species are rapidly targeted for disposal by the ubiquitin-proteasome system (UPS), and even if this should fail, and the species accumulates, the cell can also rely on the lysosome-mediated degradation pathways of autophagy. Despite the many safeguards in place, failure to maintain protein homeostasis commonly occurs during, or preceding, the onset of disease. Over the last decade and a half, studies suggest that the failure of autophagy may explain the disruption in protein homeostasis observed in disease. In this review, we will examine how the highly complex cells of the brain can become vulnerable to failure of aggregate clearance at specific points during the processive pathway of autophagy, contributing to aggregate accumulation in brains with neurodegenerative disease.

Extracellular vesicles as vital players in drug delivery: a focus on clinical disease treatment

Extracellular vesicles (EVs), a diverse population of bilayer lipid-membrane vesicles secreted by cells, have emerged as ideal drug carriers due to their efficient cellular uptake and targeted delivery capabilities. Advancements in medical and bioengineering collaborations have enabled EVs to be engineered for specific marker expression or therapeutic cargo transport, positioning them as a promising modality for treating cancer, neurological disorders, cardiovascular diseases, and beyond. EV-based drug delivery strategies offer distinct advantages, including facilitation of intercellular communication and immune modulation, high biocompatibility and stability, the ability to traverse the blood-brain barrier, and potential synergistic interactions with encapsulated therapeutics to enhance efficacy. This review explores EV isolation and scalable production, emphasizing cost-effective and reproducible manufacturing strategies, cargo-loading methodologies, and therapeutic applications. Additionally, the current landscape of EV-based targeted drug delivery, clinical translation prospects, and prevailing challenges are examined to provide a comprehensive perspective on their potential in drug delivery systems.

ESCRT Machinery in HBV Life Cycle: Dual Roles in Autophagy and Membrane Dynamics for Viral Pathogenesis

The endosomal sorting complexes required for transport (ESCRT) comprise a fundamental cellular machinery with remarkable versatility in membrane remodeling. It is multifunctional in the multivesicular body (MVB) biogenesis, exosome formation and secretion, virus budding, cytokinesis, plasma membrane repair, neuron pruning, and autophagy. ESCRT's involvement in cellular mechanisms extends beyond basic membrane trafficking. By directly interacting with autophagy-related (ATG) proteins and facilitating autophagosome-lysosome fusion, ESCRT ensures cellular homeostasis. Dysregulation in ESCRT function has been implicated in cancer, neurodegenerative disorders, and infectious diseases, underscoring its critical role in numerous pathologies. Hepatitis B virus (HBV) is an enveloped virus that exploits ESCRT and autophagy pathways for viral replication, assembly, and secretion. This review synthesizes recent mechanistic insights into ESCRT's multifaceted roles, particularly focusing on its interactions with autophagy formation and the HBV lifecycle.

Extracellular vesicles in cancer progression: mechanisms and significance

Tumor recurrence, metastasis, clinical drug resistance, and immune evasion are critical events in cancer progression, characterized by significant spatiotemporal heterogeneity and plasticity. Intercellular communication between tumor cells and other cells within the tumor microenvironment plays a pivotal role in these processes. Extracellular vesicles (EVs), heterogeneous secretory messengers carrying bioactive molecules, facilitate this cell-to-cell communication, thereby dynamically influencing cancer progression. Deciphering the mechanisms of EV formation and regulatory pathways and identifying key networks and targets in tumor metastasis, drug resistance, and immune response mediated by EVs will provide new insights into the understanding of cancer progression patterns and offer innovative strategies for cancer diagnosis and therapy.

The role and mechanism of CHMP4C in poor prognosis and drug sensitivity of lung adenocarcinoma

BACKGROUND

Chromatin modified protein 4C (CHMP4C) is a charged polyvesicular protein (CHMP) that is involved in the composition of the endosomal sorting complex (ESCRT-III) required for transport III and promotes the necessary separation of daughter cells. CHMP4C involved in a wide variety of tumor progress, such as prostate cancer, cervical cancer and lung squamous cell carcinoma. However, the value of CHMP4C in lung adenocarcinoma has not been explored.

METHODS

RNA-seq data and lung adenocarcinoma clinical information and corresponding pan-cancer were extracted from The Cancer Genome Atlas (TCGA) database to analyze CHMP4C expression and survival prognosis. The differential expression of CHMP4C was analyzed using the Human Protein Atlas (HPA) database. Clinical samples were collected to verify the differential expression of CHMP4C between lung adenocarcinoma and normal lung tissues via immunohistochemical (IHC) staining, qRT‒PCR and Western blotting. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of CHMP4C-related genes were performed. The correlation between CHMP4C and chemosensitivity was analyzed in the TCGA database. Then, qRT‒PCR, western blotting, transwell assays, cell proliferation assays, colony formation assays, wound healing assays, and cell cycle analysis were used to verify the possible regulatory mechanism involved. Molecular docking was used to predict small molecule compounds with potential roles in the treatment of lung adenocarcinoma.

RESULTS

TIMER2.0 database analysis revealed that CHMP4C was differentially expressed in different tumors.Compared with that in healthy lung tissue, CHMP4C was significantly upregulated in lung adenocarcinoma tissue, and subsequent in vitro survival analysis revealed that CHMP4C expression has significant clinical prognostic value in lung adenocarcinoma. Enrichment analysis revealed that CHMP4C was mainly related to cell proliferation, cell migration, and the PI3K-Akt signaling pathway, etc. Overexpression of CHMP4C was associated with sensitivity to chemotherapy. Knocking down CHMP4C can significantly inhibit the proliferation, migration and invasion of lung adenocarcinoma cells and prolong the G0/G1 phase of the cell cycle. Molecular docking predicts 10 key drugs that may be used for the treatment of lung adenocarcinoma.

CONCLUSIONS

CHMP4C is highly expressed in a variety of tumors. We demonstrated that CHMP4C expression may be associated with the occurrence, development, prognosis and chemotherapy sensitivity in patients with lung adenocarcinoma. These findings may open up new research directions and development opportunities for the treatment of lung adenocarcinoma.

The migrasome, an organelle for cell-cell communication

Migrasomes, newly identified extracellular organelles produced by migrating cells, are observed widely across both in vivo and in vitro studies. These organelles, rich in signaling and bioactive molecules, are pivotal in a range of physiological functions. This opinion summarizes current understanding of migrasomes, highlighting their importance as a versatile mechanism for cell-cell communication. Furthermore, it examines their roles in health and disease and potential diagnostic and therapeutic applications, and addresses the emerging challenges and open questions in this developing field.

ESCRTs - a multi-purpose membrane remodeling device encoded in all life forms

The ESCRT (endosomal sorting complexes required for transport) membrane remodeling complex, found across all life forms, exhibits a versatility that transcends evolutionary boundaries. From orchestrating the constriction of micron-wide tubes in cell division to facilitating the budding of 50 nm vesicles in receptor degradation, ESCRTs perform diverse functions in animal cells. However, the basis of this functional diversity remains enigmatic. While extensively studied in eukaryotes, the role of ESCRTs in prokaryotes is only beginning to emerge. This review synthesizes data on ESCRT systems across the tree of life, focusing on microorganisms and drawing parallels to their functions in human cells. This comparative approach highlights the remarkable plasticity of the ESCRT system across functional, structural, and genomic levels in both prokaryotes and eukaryotes. This integrated knowledge supports a model in which the ESCRT system evolved as a multipurpose membrane remodeling tool, adaptable to specific functions within and across organisms. Our review not only underscores the significance of ESCRTs in microorganisms but also paves the way for exciting avenues of research into the intricacies of cellular membrane dynamics, offering valuable insights into the evolution of cellular complexity across diverse organisms and ecosystems.

A relay race of ESCRT-III paralogs drives cell division in a hyperthermophilic archaeon

Cell division is a fundamental process ensuring the perpetuation of all cellular life forms. Archaea of the order Sulfolobales divide using a simpler version of the eukaryotic endosomal sorting complexes required for transport (ESCRT) machinery, composed of three ESCRT-III homologs (ESCRT-III, -III-1, and -III-2), AAA+ ATPase Vps4 and an archaea-specific component CdvA. Here, we clarify how these components act sequentially to drive the division of the hyperthermophilic archaeon Saccharolobus islandicus. Our data suggest that ESCRT-III plays an active role during the early stage of membrane constriction during cytokinesis, whereas ESCRT-III-1 and ESCRT-III-2 are indispensable for the "pre-late" and "late" stages of cytokinesis, respectively. In the escrt-III-1 deletion strain, the division is blocked when the mid-cell constriction reaches ~30% of the initial cell diameter ("pre-late" stage), yielding "chain-like" cellular aggregates. Depletion of ESCRT-III-2 leads to the accumulation of cells connected through narrow membrane bridges ("late" stage), consistent with the key role of this protein in the final membrane abscission. We used 3D-single molecule localization microscopy to image ESCRT-III rings of different diameters and show that the decrease in the ESCRT-III ring diameter and membrane constriction are inconsistent with a mechanism exclusively based on spiraling of the ESCRT-III filaments. By contrast, the cone-shaped assemblies of ESCRT-III-1 and ESCRT-III-2 are consistent with spiral formation, highlighting the distinct roles of the three ESCRT-III proteins during the cytokinesis. We propose the "relay race" model, whereby the cytokinesis is achieved through a sequential and concerted action of different ESCRT machinery components.

IMPORTANCE

Two major cytokinesis mechanisms, rooted in contractile FtsZ and endosomal sorting complexes required for transport (ESCRT) rings, respectively, have emerged in the course of evolution. Whereas bacteria rely on the FtsZ-based mechanism, different lineages of archaea use either of the two systems, and eukaryotes have inherited the ESCRT-based cell division machinery from their archaeal ancestors. The mechanism of ESCRT-based cell division in archaea remains poorly understood and mechanistic studies on different archaeal model systems are essential to unravel the natural history of the ESCRT machinery. Here we investigate the interplay between three major ESCRT-III homologs during the division of a hyperthermophilic archaeon Saccharolobus islandicus and propose the "relay race" model of cytokinesis.

ATG9A facilitates the closure of mammalian autophagosomes

Canonical autophagy captures within specialized double-membrane organelles, termed autophagosomes, an array of cytoplasmic components destined for lysosomal degradation. An autophagosome is completed when the growing phagophore undergoes ESCRT-dependent membrane closure, a prerequisite for its subsequent fusion with endolysosomal organelles and degradation of the sequestered cargo. ATG9A, a key integral membrane protein of the autophagy pathway, is best known for its role in the formation and expansion of phagophores. Here, we report a hitherto unappreciated function of mammalian ATG9A in directing autophagosome closure. ATG9A partners with IQGAP1 and key ESCRT-III component CHMP2A to facilitate this final stage in autophagosome formation. Thus, ATG9A is a central hub governing all major aspects of autophagosome membrane biogenesis, from phagophore formation to its closure, and is a unique ATG factor with progressive functionalities affecting the physiological outputs of autophagy.

The Asgard archaeal ESCRT-III system forms helical filaments and remodels eukaryotic-like membranes

The ESCRT machinery mediates membrane remodeling in numerous processes in cells including cell division and nuclear membrane reformation. The identification of ESCRT homologs in Asgard archaea, currently considered the closest prokaryotic relative of eukaryotes, implies a role for ESCRTs in the membrane remodeling processes that occurred during eukaryogenesis. Yet, the function of these distant ESCRT homologs is mostly unresolved. Here we show that Asgard ESCRT-III proteins of the Lokiarcheota self-assemble into helical filaments, a hallmark of the ESCRT system. We determined the cryo-EM structure of the filaments at 3.6 Å resolution and found that they share features of bacterial and eukaryotic ESCRT-III assemblies. Markedly, Asgard ESCRT-III filaments bound and deformed eukaryotic-like membrane vesicles. Oligonucleotides facilitated the assembly of ESCRT-III filaments and tuned the extent of membrane remodeling. The ability of Asgard archaeal ESCRTs to remodel eukaryotic-like membranes, which are fundamentally different from archaeal membranes, and the structural properties of these proteins places them at the junction between prokaryotes and eukaryotes.

Hypoxia as a critical player in extracellular vesicles-mediated intercellular communication between tumor cells and their surrounding microenvironment

In the past years, increasing attention has been paid to the role of extracellular vesicles (EVs) as mediators of intercellular communication in cancer. These small size particles mediate the intercellular transfer of important bioactive molecules involved in malignant initiation and progression. Hypoxia, or low partial pressure of oxygen, is recognized as a remarkable feature of solid tumors and has been demonstrated to exert a profound impact on tumor prognosis and therapeutic efficacy. Indeed, the high-pitched growth rate and chaotic neovascular architecture that embodies solid tumors results in a profound reduction in oxygen pressure within the tumor microenvironment (TME). In response to oxygen-deprived conditions, tumor cells and their surrounding milieu develop homeostatic adaptation mechanisms that contribute to the establishment of a pro-tumoral phenotype. Latest evidence suggests that the hypoxic microenvironment that surrounds the tumor bulk may be a clincher for the observed elevated levels of circulating EVs in cancer patients. Thus, it is proposed that EVs may play a role in mediating intercellular communication in response to hypoxic conditions. This review focuses on the EVs-mediated crosstalk that is established between tumor cells and their surrounding immune, endothelial, and stromal cell populations, within the hypoxic TME.

Current status, opportunities, and challenges of exosomes in diagnosis and treatment of osteoarthritis

Osteoarthritis (OA) is a progressive joint disease that is a frequent reason for pain and physical dysfunction in adults, with enormous social and economic burden. Although ongoing scientific efforts in recent years have made considerable progress towards understanding of the disease's molecular mechanism, the pathogenesis of OA is still not fully known, and its clinical challenge remains. Thus, elucidating molecular events underlying the initiation and progression of OA is crucial for developing novel diagnostic and therapeutic approaches that could facilitate effective clinical management of the illness. Exosomes, extracellular vesicles containing various cellular components with approximately a diameter of 100 nm, act as essential mediators in physiological and pathological processes by modulating cell-to-cell communications. Exosomes have crucial roles in biological events such as intercellular communication, regulation of gene expression, apoptosis, inflammation, immunity, maturation and differentiation due to their inner composition, which includes nucleic acids, proteins, and lipids. We focus on the roles of exosomes in OA pathogenesis and discuss how they might be used in clinical practice for OA diagnosis and treatment. Our paper not only provides a comprehensive review of exosomes in OA but also contributes to the development efforts of diagnostic and therapeutic tools for OA.

ESCRT elicits vacuolar fission in the absence of Vps4 in budding yeast

In budding yeast, endosomal sorting complex required for transport (ESCRT) mediates microautophagy by vacuolar membrane invagination into the vacuolar lumen, followed by Vps4-assisted membrane constriction and abscission. Here, we show that ESCRT elicits vacuolar fission in the absence of Vps4 after nutrient starvation, although vacuolar fusion is facilitated in wild-type cells in these conditions. ESCRT mediated vacuolar membrane invagination in vps4Δ cells, thereby causing vacuolar fission. It is known that vacuolar fission requires phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) and β-propellers that bind polyphosphoinositides (PROPPINs), PI(3,5)P2-binding proteins. However, PROPPIN, but not PI(3,5)P2, was dispensable for the ESCRT-mediated vacuolar fragmentation. Finally, we showed evidence that microlipophagy triggers vacuolar fission. Thus, disruption of the coordinated sequence of ESCRT-Vps4 operations in microautophagy leads to vacuolar fragmentation. This study provides insight into the ESCRT-Vps4 axis-dependent cellular disfunctions and related diseases.

Extracellular vesicular microRNAs and cardiac hypertrophy

Cardiac hypertrophy is an adaptive response to pressure or volume overload such as hypertension and ischemic heart diseases. Sustained cardiac hypertrophy eventually leads to heart failure. The pathophysiological alterations of hypertrophy are complex, involving both cellular and molecular systems. Understanding the molecular events that inhibit or repress cardiac hypertrophy may help identify novel therapeutic strategies. Increasing evidence has indicated that extracellular vesicle (EV)-derived microRNAs (miRNAs) play a significant role in the development and progression of cardiac hypertrophy. In this review, we briefly review recent advancements in EV research, especially on biogenesis, cargoes and its role in cardiac hypertrophy. We then describe the latest findings regarding EV-derived miRNAs, highlighting their functions and regulatory mechanisms in cardiac hypertrophy. Finally, the potential role of EV-derived miRNAs as targets in the diagnosis and treatment of cardiac hypertrophy will be discussed.

Biological Cargo: Exosomes and their Role in Cancer Progression and Metastasis

Cancer cells are among the many types of cells that release exosomes, which are nanovesicles. Because of their many potential applications, exosomes have recently garnered much attention from cancer researchers. The bioactive substances that exosomes release as cargo have been the subject of several investigations. The substances in question may operate as biomarkers for diagnosis or affect apoptosis, the immune system, the development and spread of cancer, and other processes. Others have begun to look at exosomes in experimental therapeutic trials because they believe they may be useful in the treatment of cancer. This review started with a short description of exosome biogenesis and key features. Next, the potential of tumor-derived exosomes and oncosomes to influence the immune system throughout the development of cancer, as well as alter tumor microenvironments (TMEs) and pre-metastatic niche creation, was investigated. Finally, there was talk of exosomes' possible use in cancer treatment. Furthermore, there is emerging consensus about the potential application of exosomes to be biological reprogrammers of cancer cells, either as carriers of naturally occurring chemicals, including anticancer medications, or as carriers of anticancer vaccines for immunotherapy as well as boron neutron capture therapy (BNCT). We briefly review the key ideas and logic behind this intriguing therapy recommendation.

A review of the roles of exosomes in salivary gland diseases with an emphasis on primary Sjögren's syndrome

Salivary gland diseases encompass a broad range of conditions, including autoimmune, inflammatory, obstructive, and neoplastic disorders, significantly impacting oral health and overall well-being. Recent research has highlighted the crucial role of exosomes, small extracellular vesicles, in these diseases. Exosomes mediate intercellular communication by transferring bioactive molecules such as proteins, microRNAs, and lipids, positioning them as potential diagnostic biomarkers and therapeutic agents. In primary Sjögren's syndrome (pSS), exosomes derived from Epstein-Barr virus-infected B cells and activated T cells transfer key microRNAs that impair calcium signaling, contributing to glandular dysfunction. Exosome-based biomarkers like Ro/SSA and La/SSB, found in saliva, serum, and tears, offer non-invasive diagnostic tools for early disease detection. Furthermore, mesenchymal stem cell-derived exosomes show promise in treating pSS by modulating immune responses and promoting tissue repair. While exosomes hold promise for the diagnosis and treatment of other salivary gland diseases, such as radiation-induced xerostomia and sialolithiasis, their application remains limited, necessitating further research to unlock their full diagnostic and therapeutic potential. This review focuses on the role of exosomes in salivary gland diseases, with an emphasis on pSS, and highlights the need for future clinical applications and large-scale trials.

Exosomes as nature's nano carriers: Promising drug delivery tools and targeted therapy for glioma

Exosomes, minute vesicles originating from diverse cell types, exhibit considerable potential as carriers for drug delivery in glioma therapy. These naturally occurring nanocarriers facilitate the transfer of proteins, RNAs, and lipids between cells, offering advantages such as biocompatibility, efficient cellular absorption, and the capability to traverse the blood-brain barrier (BBB). In the realm of cancer, particularly gliomas, exosomes play pivotal roles in modulating tumor growth, regulating immunity, and combating drug resistance. Moreover, exosomes serve as valuable biomarkers for diagnosing diseases and assessing prognosis. This review aims to elucidate the therapeutic and diagnostic promise of exosomes in glioma treatment, highlighting the innovative advances in exosome engineering that enable precise drug loading and targeting. By circumventing challenges associated with current glioma treatments, exosome-mediated drug delivery strategies can enhance the efficacy of chemotherapy drugs like temozolomide and overcome drug resistance mechanisms. This review underscores the multifaceted roles of exosomes in glioma pathogenesis and therapy, underscoring their potential as natural nanocarriers for targeted therapy and heralding a new era of hope for glioma treatment.

CHMP2B promotes CHMP7 mediated nuclear pore complex injury in sporadic ALS

Alterations to the composition and function of neuronal nuclear pore complexes (NPCs) have been documented in multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis (ALS). Moreover, recent work has suggested that injury to the NPC can at least in part contribute to TDP-43 loss of function and mislocalization, a pathological hallmark of ALS and related neurodegenerative diseases. Collectively, these studies highlight a role for disruptions in NPC homeostasis and surveillance as a significant pathophysiologic event in neurodegeneration. The ESCRT-III nuclear surveillance pathway plays a critical role in the surveillance and maintenance of NPCs and the surrounding nuclear environment. Importantly, pathologic alterations to this pathway and its protein constituents have been implicated in neurodegenerative diseases such as ALS. However, the mechanism by which this pathway contributes to disease associated alterations in the NPC remains unknown. Here we use an induced pluripotent stem cell (iPSC) derived neuron (iPSN) model of sALS to demonstrate that CHMP7/ESCRT-III nuclear maintenance/surveillance is overactivated in sALS neurons. This overactivation is dependent upon the ESCRT-III protein CHMP2B and sustained CHMP2B dependent "activation" is sufficient to contribute to pathologic CHMP7 nuclear accumulation and POM121 reduction. Importantly, partial knockdown of CHMP2B was sufficient to alleviate NPC injury and downstream TDP-43 dysfunction in sALS neurons thereby highlighting CHMP2B as a potential therapeutic target in disease.

Mechanism to disrupt ESCRT-mediated intracellular trafficking through Vps28-small molecules interaction: an in silico approach

The ESCRT (Endosomal Sorting Complex Required for Transport) machinery comprising protein complexes ESCRT-0 to ESCRT-III and Vps4 plays a pivotal role in intracellular trafficking, a process of endocytosing cell surface proteins into the cell for various biological activities. The ESCRT protein complexes are sequentially assembled which interact amongst each other to form a functional ESCRT machinery. Deregulation of these events are shown to be involved in various disease development including tumor formation and viral infections. Recently upregulation of a crucial ESCRT protein, Vps28 has been shown to be implicated in tumor formation. However, Vps28 in ESCRT-I interacts with Vps36 in ESCRT-II to function as a connecting protein during ESCRT machinery formation. Until now biomolecular approaches to inhibit the formation/assembly of ESCRT machinery have not been developed. Hence, we hypothesized that disrupting Vps28/Vps36 interaction would prevent assembly of ESCRT machinery and offer therapeutic potential to restrict disease development and progression. To address this, we utilized a virtual screening approach using a flavonoid-based library to identify potential small molecule inhibitors that can bind to Vps28 active site. Based on the binding affinity, top-hit compounds were identified. Molecular dynamics simulations set over a 500 ns timescale demonstrated the stability of the Vps28-small molecule complexes. Per-residue decomposition analysis using Molecular Mechanics/Poisson-Boltzmann surface area highlighted the significant contributions of active site residues Asn189, Arg190, Arg193 and Asn210 in Vps28 for interaction with small molecules. Absorption, Distribution, Metabolism, Excretion, and Toxicity analysis for toxicity evaluation indicates that molecules Z0131, H0194, Z0199 and DQ00112 exhibited physicochemical properties suitable for drug development.

Nuclear and degradative functions of the ESCRT-III pathway: implications for neurodegenerative disease

The ESCRT machinery plays a pivotal role in membrane-remodeling events across multiple cellular processes including nuclear envelope repair and reformation, nuclear pore complex surveillance, endolysosomal trafficking, and neuronal pruning. Alterations in ESCRT-III functionality have been associated with neurodegenerative diseases including Frontotemporal Dementia (FTD), Amyotrophic Lateral Sclerosis (ALS), and Alzheimer's Disease (AD). In addition, mutations in specific ESCRT-III proteins have been identified in FTD/ALS. Thus, understanding how disruptions in the fundamental functions of this pathway and its individual protein components in the human central nervous system (CNS) may offer valuable insights into mechanisms underlying neurodegenerative disease pathogenesis and identification of potential therapeutic targets. In this review, we discuss ESCRT components, dynamics, and functions, with a focus on the ESCRT-III pathway. In addition, we explore the implications of altered ESCRT-III function for neurodegeneration with a primary emphasis on nuclear surveillance and endolysosomal trafficking within the CNS.

The theragnostic advances of exosomes in managing leukaemia

Leukaemia, a group of haematological malignancies, presents ongoing diagnosis, prognosis, and treatment challenges. A major obstacle in treating this disease is the development of drug resistance. Overcoming drug resistance poses a significant barrier to effective leukaemia treatment. The emergence of exosome research has unveiled new insights into the probable theragnostic implementations in leukaemia. Various research has exhibited the diagnostic possibilities of exosomes in identifying leukaemia-specific biomarkers, including genetic mutations and fusion transcripts. Additionally, exosomes have been implicated in disease progression and treatment response, rendering them appealing targets for therapeutics. Exosomes, originating from diverse cell types, are instrumental in intercellular communication as they participate in the functional transportation of molecules like proteins, nucleic acids and lipids across space. Exosomes have a dual role in immune regulation, mediating immune suppression and modulating anti-leukaemia immune responses. Interestingly, exosomes can even act as drug transport vehicles. This review delves into the intricate process of exosome biogenesis, shedding light on their formation and release from donor cells. The key mechanisms engaged in exosome biogenesis, for instance, the endosomal sorting complexes required for transport (ESCRT) machinery and ESCRT-independent pathways, are thoroughly discussed. Looking ahead, future approaches that leverage innovative technologies hold the promise of revolutionizing disease management and improving patient outcomes.

Extracellular vesicles versus lipid nanoparticles for the delivery of nucleic acids

Extracellular vesicles (EVs) are increasingly investigated for delivering nucleic acid (NA) therapeutics, leveraging their natural role in transporting NA and protein-based cargo in cell-to-cell signaling. Their synthetic counterparts, lipid nanoparticles (LNPs), have been developed over the past decades as NA carriers, culminating in the approval of several marketed formulations such as patisiran/Onpattro® and the mRNA-1273/BNT162 COVID-19 vaccines. The success of LNPs has sparked efforts to develop innovative technologies to target extrahepatic organs, and to deliver novel therapeutic modalities, such as tools for in vivo gene editing. Fueled by the recent advancements in both fields, this review aims to provide a comprehensive overview of the basic characteristics of EV and LNP-based NA delivery systems, from EV biogenesis to structural properties of LNPs. It addresses the primary challenges encountered in utilizing these nanocarriers from a drug formulation and delivery perspective. Additionally, biodistribution profiles, in vitro and in vivo transfection outcomes, as well as their status in clinical trials are compared. Overall, this review provides insights into promising research avenues and potential dead ends for EV and LNP-based NA delivery systems.

Cytoplasmic nucleoporin assemblage: the cellular artwork in physiology and disease

Nucleoporins, essential proteins building the nuclear pore, are pivotal for ensuring nucleocytoplasmic transport. While traditionally confined to the nuclear envelope, emerging evidence indicates their presence in various cytoplasmic structures, suggesting potential non-transport-related roles. This review consolidates findings on cytoplasmic nucleoporin assemblies across different states, including normal physiological conditions, stress, and pathology, exploring their structural organization, formation dynamics, and functional implications. We summarize the current knowledge and the latest concepts on the regulation of nucleoporin homeostasis, aiming to enhance our understanding of their unexpected roles in physiological and pathological processes.

Molecular Targeting of Ischemic Stroke: The Promise of Naïve and Engineered Extracellular Vesicles

Ischemic stroke (IS) remains a leading cause of mortality and long-term disability worldwide, with limited therapeutic options available. Despite the success of early interventions, such as tissue-type plasminogen activator administration and mechanical thrombectomy, many patients continue to experience persistent neurological deficits. The pathophysiology of IS is multifaceted, encompassing excitotoxicity, oxidative and nitrosative stress, inflammation, and blood-brain barrier disruption, all of which contribute to neural cell death, further complicating the treatment of IS. Recently, extracellular vesicles (EVs) secreted naturally by various cell types have emerged as promising therapeutic agents because of their ability to facilitate selective cell-to-cell communication, neuroprotection, and tissue regeneration. Furthermore, engineered EVs, designed to enhance targeted delivery and therapeutic cargo, hold the potential to improve their therapeutic benefits by mitigating neuronal damage and promoting neurogenesis and angiogenesis. This review summarizes the characteristics of EVs, the molecular mechanisms underlying IS pathophysiology, and the emerging role of EVs in IS treatment at the molecular level. This review also explores the recent advancements in EV engineering, including the incorporation of specific proteins, RNAs, or pharmacological agents into EVs to enhance their therapeutic efficacy.

Role of purinoreceptors in the release of extracellular vesicles and consequences on immune response and cancer progression

Cell-to-cell communication is a major process for accommodating cell functioning to changes in the environments and to preserve tissue and organism homeostasis. It is achieved by different mechanisms characterized by the origin of the message, the molecular nature of the messenger, its speed of action and its reach. Purinergic signalling is a powerful mechanism initiated by extracellular nucleotides, such as ATP, acting on plasma membrane purinoreceptors. Purinergic signalling is tightly controlled in time and space by the action of ectonucleotidases. Recent studies have highlighted the critical role of purinergic signalling in controlling the generation, release and fate of extracellular vesicles and, in this way, mediating long-distance responses. Most of these discoveries have been made in immune and cancer cells. This review is aimed at establishing the current knowledge on the way which purinoreceptors control extracellular vesicle-mediated communications and consequences for recipient cells.

SARS-CoV-2 Assembly: Gaining Infectivity and Beyond

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was responsible for causing the COVID-19 pandemic. Intensive research has illuminated the complex biology of SARS-CoV-2 and its continuous evolution during and after the COVID-19 pandemic. While much attention has been paid to the structure and functions of the viral spike protein and the entry step of viral infection, partly because these are targets for neutralizing antibodies and COVID-19 vaccines, the later stages of SARS-CoV-2 replication, including the assembly and egress of viral progenies, remain poorly characterized. This includes insight into how the activities of the viral structural proteins are orchestrated spatially and temporally, which cellular proteins are assimilated by the virus to assist viral assembly, and how SARS-CoV-2 counters and evades the cellular mechanisms antagonizing virus assembly. In addition to becoming infectious, SARS-CoV-2 progenies also need to survive the hostile innate and adaptive immune mechanisms, such as recognition by neutralizing antibodies. This review offers an updated summary of the roles of SARS-CoV-2 structural proteins in viral assembly, the regulation of assembly by viral and cellular factors, and the cellular mechanisms that restrict this process. Knowledge of these key events often reveals the vulnerabilities of SARS-CoV-2 and aids in the development of effective antiviral therapeutics.

QTL Mapping-Based Identification of Visceral White-Nodules Disease Resistance Genes in Larimichthys polyactis

Disease outbreaks in aquaculture have recently intensified. In particular, visceral white-nodules disease, caused by Pseudomonas plecoglossicida, has severely hindered the small yellow croaker (Larimichthys polyactis) aquaculture industry. However, research on this disease is limited. To address this gap, the present study employed a 100K SNP chip to genotype individuals from an F1 full-sib family, identify single nucleotide polymorphisms (SNPs), and construct a genetic linkage map for this species. A high-density genetic linkage map spanning a total length of 1395.72 cM with an average interval of 0.08 cM distributed across 24 linkage groups was obtained. Employing post-infection survival time as an indicator of disease resistance, 13 disease resistance-related quantitative trait loci (QTLs) were detected, and these regions included 169 genes. Functional enrichment analyses pinpointed 11 candidate disease resistance-related genes. RT-qPCR analysis revealed that the genes of chmp1a and arg1 are significantly differentially expressed in response to P. plecoglossicida infection in spleen and liver tissues, indicating their pivotal functions in disease resistance. In summary, in addition to successfully constructing a high-density genetic linkage map, this study reports the first QTL mapping for visceral white-nodules disease resistance. These results provide insight into the intricate molecular mechanisms underlying disease resistance in the small yellow croaker.

Extracellular vesicles of Norway spruce contain precursors and enzymes for lignin formation and salicylic acid

Lignin is a phenolic polymer in plants that rigidifies the cell walls of water-conducting tracheary elements and support-providing fibers and stone cells. Different mechanisms have been suggested for the transport of lignin precursors to the site of lignification in the cell wall. Extracellular vesicle (EV)-enriched samples isolated from a lignin-forming cell suspension culture of Norway spruce (Picea abies L. Karst.) contained both phenolic metabolites and enzymes related to lignin biosynthesis. Metabolomic analysis revealed mono-, di-, and oligolignols in the EV isolates, as well as carbohydrates and amino acids. In addition, salicylic acid (SA) and some proteins involved in SA signaling were detected in the EV-enriched samples. A proteomic analysis detected several laccases, peroxidases, β-glucosidases, putative dirigent proteins, and cell wall-modifying enzymes, such as glycosyl hydrolases, transglucosylase/hydrolases, and expansins in EVs. Our findings suggest that EVs are involved in transporting enzymes required for lignin polymerization in Norway spruce, and radical coupling of monolignols can occur in these vesicles.

Hitting the target: cell signaling pathways modulation by extracellular vesicles

Extracellular vesicles (EVs) are lipid bilayer-enclosed nanoparticles released outside the cell. EVs have drawn attention not only for their role in cell waste disposal, but also as additional tools for cell-to-cell communication. Their complex contents include not only lipids, but also proteins, nucleic acids (RNA, DNA), and metabolites. A large part of these molecules are involved in mediating or influencing signal transduction in target cells. In multicellular organisms, EVs have been suggested to modulate signals in cells localized either in the neighboring tissue or in distant regions of the body by interacting with the cell surface or by entering the cells via endocytosis or membrane fusion. Most of the EV-modulated cell signaling pathways have drawn considerable attention because they affect morphogenetic signaling pathways, as well as pathways activated by cytokines and growth factors. Therefore, they are implicated in relevant biological processes, such as embryonic development, cancer initiation and spreading, tissue differentiation and repair, and immune response. Furthermore, it has recently emerged that multicellular organisms interact with and receive signals through EVs released by their microbiota as well as by edible plants. This review reports studies investigating EV-mediated signaling in target mammalian cells, with a focus on key pathways for organism development, organ homeostasis, cell differentiation and immune response.

Temporal insights into molecular and cellular responses during rAAV production in HEK293T cells

The gene therapy field seeks cost-effective, large-scale production of recombinant adeno-associated virus (rAAV) vectors for high-dosage therapeutic applications. Although strategies like suspension cell culture and transfection optimization have shown moderate success, challenges persist for large-scale applications. To unravel molecular and cellular mechanisms influencing rAAV production, we conducted an SWATH-MS proteomic analysis of HEK293T cells transfected using standard, sub-optimal, and optimal conditions. Gene Ontology and pathway analysis revealed significant protein expression variations, particularly in processes related to cellular homeostasis, metabolic regulation, vesicular transport, ribosomal biogenesis, and cellular proliferation under optimal transfection conditions. This resulted in a 50% increase in rAAV titer compared with the standard protocol. Additionally, we identified modifications in host cell proteins crucial for AAV mRNA stability and gene translation, particularly regarding AAV capsid transcripts under optimal transfection conditions. Our study identified 124 host proteins associated with AAV replication and assembly, each exhibiting distinct expression pattern throughout rAAV production stages in optimal transfection condition. This investigation sheds light on the cellular mechanisms involved in rAAV production in HEK293T cells and proposes promising avenues for further enhancing rAAV titer during production.

Exosomes That Have Different Cellular Origins Followed by the Impact They Have on Prostate Tumor Development in the Tumor Microenvironment

BACKGROUND

Prostate cancer (PCa) is the most common urinary tumor with the highest incidence rate and the second among the leading causes of death worldwide for adult males. In the worldwide cancer incidence rate, PCa is on the increase. The cancerous cells in the prostate and cells in the microenvironment surrounding the tumor communicate through signal transduction, which is crucial for the development and spread of PCa.

RECENT FINDINGS

Exosomes are nanoscale vesicles released into body fluids by various cells that can aid intercellular communication by releasing nucleic acids and proteins. Exosomes published by different types of cells in the tumor microenvironment can have varying impacts on the proliferation and growth of tumor cells via various signaling pathways, modes of action, and secreted cytokines.

CONCLUSION

The main purpose of this review is to describe the effects of different cell-derived exosomes in the tumor microenvironment of PCa on the progression of tumor cells, as well as to summarize and discuss the prospects for the application of exosomes in the treatment and diagnosis of PCa.

Clearing the JUNQ: the molecular machinery for sequestration, localization, and degradation of the JUNQ compartment

Cellular protein homeostasis (proteostasis) plays an essential role in regulating the folding, sequestration, and turnover of misfolded proteins via a network of chaperones and clearance factors. Previous work has shown that misfolded proteins are spatially sequestered into membrane-less compartments in the cell as part of the proteostasis process. Soluble misfolded proteins in the cytoplasm are trafficked into the juxtanuclear quality control compartment (JUNQ), and nuclear proteins are sequestered into the intranuclear quality control compartment (INQ). However, the mechanisms that control the formation, localization, and degradation of these compartments are unknown. Previously, we showed that the JUNQ migrates to the nuclear membrane adjacent to the INQ at nucleus-vacuole junctions (NVJ), and the INQ moves through the NVJ into the vacuole for clearance in an ESCRT-mediated process. Here we have investigated what mechanisms are involved in the formation, migration, and clearance of the JUNQ. We find Hsp70s Ssa1 and Ssa2 are required for JUNQ localization to the NVJ and degradation of cytoplasmic misfolded proteins. We also confirm that sequestrases Btn2 and Hsp42 sort misfolded proteins to the JUNQ or IPOD, respectively. Interestingly, proteins required for piecemeal microautophagy of the nucleus (PMN) (i.e., Nvj1, Vac8, Atg1, and Atg8) drive the formation and clearance of the JUNQ. This suggests that the JUNQ migrates to the NVJ to be cleared via microautophagy.

Physiological functions of ULK1/2

UNC-51-like kinases 1 and 2 (ULK1/2) are serine/threonine kinases that are best known for their evolutionarily conserved role in the autophagy pathway. Upon sensing the nutrient status of a cell, ULK1/2 integrate signals from upstream cellular energy sensors such as mTOR and AMPK and relay them to the downstream components of the autophagy machinery. ULK1/2 also play indispensable roles in the selective autophagy pathway, removing damaged mitochondria, invading pathogens, and toxic protein aggregates. Additional functions of ULK1/2 have emerged beyond autophagy, including roles in protein trafficking, RNP granule dynamics, and signaling events impacting innate immunity, axon guidance, cellular homeostasis, and cell fate. Therefore, it is no surprise that alterations in ULK1/2 expression and activity have been linked with pathophysiological processes, including cancer, neurological disorders, and cardiovascular diseases. Growing evidence suggests that ULK1/2 function as biological rheostats, tuning cellular functions to intra and extra-cellular cues. Given their broad physiological relevance, ULK1/2 are candidate targets for small molecule activators or inhibitors that may pave the way for the development of therapeutics for the treatment of diseases in humans.

Extracellular Vesicle Preparation and Analysis: A State-of-the-Art Review

In recent decades, research on Extracellular Vesicles (EVs) has gained prominence in the life sciences due to their critical roles in both health and disease states, offering promising applications in disease diagnosis, drug delivery, and therapy. However, their inherent heterogeneity and complex origins pose significant challenges to their preparation, analysis, and subsequent clinical application. This review is structured to provide an overview of the biogenesis, composition, and various sources of EVs, thereby laying the groundwork for a detailed discussion of contemporary techniques for their preparation and analysis. Particular focus is given to state-of-the-art technologies that employ both microfluidic and non-microfluidic platforms for EV processing. Furthermore, this discourse extends into innovative approaches that incorporate artificial intelligence and cutting-edge electrochemical sensors, with a particular emphasis on single EV analysis. This review proposes current challenges and outlines prospective avenues for future research. The objective is to motivate researchers to innovate and expand methods for the preparation and analysis of EVs, fully unlocking their biomedical potential.

Infection and intracellular transport of white spot syndrome virus require the ESCRT machinery in shrimp

The cellular endosomal sorting complex required for transport (ESCRT) system comprises five distinct components and is involved in many different physiological processes. Recent studies have shown that different viruses rely upon the host ESCRT system for viral infection. However, whether this system is involved in white spot syndrome virus (WSSV) infection remains unclear. Here, we identified 24 homologs of ESCRT subunits in kuruma shrimp, Marsupenaeus japonicus, and found that some key components were strongly upregulated in shrimp after WSSV infection. Knockdown of key components of the ESCRT system using RNA interference inhibited virus replication, suggesting that the ESCRT system is beneficial for WSSV infection. We further focused on TSG101, a crucial member of the ESCRT-I family that plays a central role in recognizing cargo and activating the ESCRT-II and ESCRT-III complexes. TSG101 colocalized with WSSV in hemocytes. The addition of N16 (a TSG101 inhibitor) markedly decreased WSSV replication. TSG101 and ALIX of the ESCRT system interact with WSSV envelope proteins. The host proteins TSG101, RAB5, and RAB7, the viral protein VP28, and DNA were detected in endosomes isolated from hemocytes of WSSV-infected shrimp. Knockdown of Rab5 and Rab7 expression reduced viral replication. Taken together, these results suggest that the ESCRT system is hijacked by WSSV for transport through the early to late endosome pathway. Our work identified a novel requirement for the intracellular trafficking and infection of WSSV, and provided novel therapeutic targets for the prevention and control of WSSV in shrimp aquaculture.

IMPORTANCE

Viruses utilize the ESCRT machinery in a variety of strategies for their replication and infection. This study revealed that the interaction of ESCRT complexes with WSSV envelope proteins plays a crucial role in WSSV infection in shrimp. The ESCRT system is conserved in the shrimp Marsupenaeus japonicus, and 24 homologs of the ESCRT system were identified in the shrimp. WSSV exploits the ESCRT system for transport and propagation via the interaction of envelope proteins with host TSG101 and ALIX in an endosome pathway-dependent manner. Understanding the underlying mechanisms of WSSV infection is important for disease control and breeding in shrimp aquaculture.

The Conserved YPX3L Motif in the BK Polyomavirus VP1 Protein Is Important for Viral Particle Assembly but Not for Its Secretion into Extracellular Vesicles

The BK polyomavirus (BKPyV) is a small DNA non-enveloped virus whose infection is asymptomatic in most of the world's adult population. However, in cases of immunosuppression, the reactivation of the virus can cause various complications, and in particular, nephropathies in kidney transplant recipients or hemorrhagic cystitis in bone marrow transplant recipients. Recently, it was demonstrated that BKPyV virions can use extracellular vesicles to collectively traffic in and out of cells, thus exiting producing cells without cell lysis and entering target cells by diversified entry routes. By a comparison to other naked viruses, we investigated the possibility that BKPyV virions recruit the Endosomal-Sorting Complexes Required for Transport (ESCRT) machinery through late domains in order to hijack extracellular vesicles. We identified a single potential late domain in the BKPyV structural proteins, a YPX3L motif in the VP1 protein, and used pseudovirions to study the effect of point mutations found in a BKPyV clinical isolate or known to ablate the interaction of such a domain with the ESCRT machinery. Our results suggest that this domain is not involved in BKPyV association with extracellular vesicles but is crucial for capsomere interaction and thus viral particle assembly.

Role of Toll-like receptors in exosome biogenesis and angiogenesis capacity

Adaptive inflammation consists of multiple cellular changes and molecular reactions to protect host cells against several pathological conditions. Along with the activation of varied immune cells, the production and secretion of cytokines arrays can regulate the progression of inflammatory response in a paracrine manner. Among different molecular cascades, Toll-like receptors (TLRs) are activated in response to several pathological conditions and damage signals. It has been indicated that extracellular vesicles, especially exosomes (Exos) are key bioshuttles with specific cargoes and are involved in cell-to-cell communication. The role of Exos in the initiation, progression, and cession of inflammation has been previously addressed in terms of cytokine transmission. Whether and how the activation of TLRs can alter the Exo biogenesis and angiogenesis potential in immune cells and endothelial cells (ECs) remains to be elucidated. Here, the cross-talk between the TLRs, Exo biogenesis, and angiogenesis has been highlighted.

The precise function of alphaherpesvirus tegument proteins and their interactions during the viral life cycle

Alphaherpesvirus is a widespread pathogen that causes diverse diseases in humans and animals and can severely damage host health. Alphaherpesvirus particles comprise a DNA core, capsid, tegument and envelope; the tegument is located between the nuclear capsid and envelope. According to biochemical and proteomic analyses of alphaherpesvirus particles, the tegument contains at least 24 viral proteins and plays an important role in the alphaherpesvirus life cycle. This article reviews the important role of tegument proteins and their interactions during the viral life cycle to provide a reference and inspiration for understanding alphaherpesvirus infection pathogenesis and identifying new antiviral strategies.

CD63 sorts cholesterol into endosomes for storage and distribution via exosomes

Extracellular vesicles such as exosomes are now recognized as key players in intercellular communication. Their role is influenced by the specific repertoires of proteins and lipids, which are enriched when they are generated as intraluminal vesicles (ILVs) in multivesicular endosomes. Here we report that a key component of small extracellular vesicles, the tetraspanin CD63, sorts cholesterol to ILVs, generating a pool that can be mobilized by the NPC1/2 complex, and exported via exosomes to recipient cells. In the absence of CD63, cholesterol is retrieved from the endosomes by actin-dependent vesicular transport, placing CD63 and cholesterol at the centre of a balance between inward and outward budding of endomembranes. These results establish CD63 as a lipid-sorting mechanism within endosomes, and show that ILVs and exosomes are alternative providers of cholesterol.

Extracellular vesicles as modulators of monocyte and macrophage function in tumors

The tumor microenvironment (TME) harbors several cell types, such as tumor cells, immune cells, and non-immune cells. These cells communicate through several mechanisms, such as cell-cell contact, cytokines, chemokines, and extracellular vesicles (EVs). Tumor-derived vesicles are known to have the ability to modulate the immune response. Monocytes are a subset of circulating innate immune cells and play a crucial role in immune surveillance, being recruited to tissues where they differentiate into macrophages. In the context of tumors, it has been observed that tumor cells can attract monocytes to the TME and induce their differentiation into tumor-associated macrophages with a pro-tumor phenotype. Tumor-derived EVs have emerged as essential structures mediating this process. Through the transfer of specific molecules and signaling factors, tumor-derived EVs can shape the phenotype and function of monocytes, inducing the expression of cytokines and molecules by these cells, thus modulating the TME towards an immunosuppressive environment.

Intrinsic Disorder in the Host Proteins Entrapped in Rabies Virus Particles

A proteomics analysis of purified rabies virus (RABV) revealed 47 entrapped host proteins within the viral particles. Out of these, 11 proteins were highly disordered. Our study was particularly focused on five of the RABV-entrapped mouse proteins with the highest levels of disorder: Neuromodulin, Chmp4b, DnaJB6, Vps37B, and Wasl. We extensively utilized bioinformatics tools, such as FuzDrop, D2P2, UniProt, RIDAO, STRING, AlphaFold, and ELM, for a comprehensive analysis of the intrinsic disorder propensity of these proteins. Our analysis suggested that these disordered host proteins might play a significant role in facilitating the rabies virus pathogenicity, immune system evasion, and the development of antiviral drug resistance. Our study highlighted the complex interaction of the virus with its host, with a focus on how the intrinsic disorder can play a crucial role in virus pathogenic processes, and suggested that these intrinsically disordered proteins (IDPs) and disorder-related host interactions can also be a potential target for therapeutic strategies.

Comparative proteomic analysis of three major extracellular vesicle classes secreted from human primary and metastatic colorectal cancer cells: Exosomes, microparticles, and shed midbody remnants

Cell-derived extracellular vesicles (EVs) are evolutionary-conserved secretory organelles that, based on their molecular composition, are important intercellular signaling regulators. At least three classes of circulating EVs are known based on mechanism of biogenesis: exosomes (sEVs/Exos), microparticles (lEVs/MPs), and shed midbody remnants (lEVs/sMB-Rs). sEVs/Exos are of endosomal pathway origin, microparticles (lEVs/MPs) from plasma membrane blebbing and shed midbody remnants (lEVs/sMB-Rs) arise from symmetric cytokinetic abscission. Here, we isolate sEVs/Exos, lEVs/MPs, and lEVs/sMB-Rs secreted from human isogenic primary (SW480) and metastatic (SW620) colorectal cancer (CRC) cell lines in milligram quantities for label-free MS/MS-based proteomic profiling. Purified EVs revealed selective composition packaging of exosomal protein markers in SW480/SW620-sEVs/Exos, metabolic enzymes in SW480/SW620-lEVs/MPs, while centralspindlin complex proteins, nucleoproteins, splicing factors, RNA granule proteins, translation-initiation factors, and mitochondrial proteins selectively traffic to SW480/SW620- lEVs/sMB-Rs. Collectively, we identify 39 human cancer-associated genes in EVs; 17 associated with SW480-EVs, 22 with SW620-EVs. We highlight oncogenic receptors/transporters selectively enriched in sEVs/Exos (EGFR/FAS in SW480-sEVs/Exos and MET, TGFBR2, ABCB1 in SW620-sEVs/Exos). Interestingly, MDK, STAT1, and TGM2 are selectively enriched in SW480-lEVs/sMB-Rs, and ADAM15 to SW620-lEVs/sMB-Rs. Our study reveals sEVs/Exos, lEVs/MPs, and lEVs/sMB-Rs have distinct protein signatures that open potential diagnostic avenues of distinct types of EVs for clinical utility.

Tau fibrils induce nanoscale membrane damage and nucleate cytosolic tau at lysosomes

The prion-like spread of protein aggregates is a leading hypothesis for the propagation of neurofibrillary lesions in the brain, including the spread of tau inclusions associated with Alzheimer's disease. The mechanisms of cellular uptake of tau seeds and subsequent nucleated polymerization of cytosolic tau are major questions in the field, and the potential for coupling between the entry and nucleation mechanisms has been little explored. We found that in primary astrocytes and neurons, endocytosis of tau seeds leads to their accumulation in lysosomes. This in turn leads to lysosomal swelling, deacidification, and recruitment of ESCRT proteins, but not Galectin-3, to the lysosomal membrane. These observations are consistent with nanoscale damage of the lysosomal membrane. Live cell imaging and STORM superresolution microscopy further show that the nucleation of cytosolic tau occurs primarily at the lysosome membrane under these conditions. These data suggest that tau seeds escape from lysosomes via nanoscale damage rather than wholesale rupture and that nucleation of cytosolic tau commences as soon as tau fibril ends emerge from the lysosomal membrane.

Designing molecules: directing stem cell differentiation

Stem cells have been widely applied in regenerative and therapeutic medicine for their unique regenerative properties. Although much research has shown their potential, it remains tricky in directing stem cell differentiation. The advancement of genetic and therapeutic technologies, however, has facilitated this issue through development of design molecules. These molecules are designed to overcome the drawbacks previously faced, such as unexpected differentiation outcomes and insufficient migration of endogenous or exogenous MSCs. Here, we introduced aptamer, bacteriophage, and biological vectors as design molecules and described their characteristics. The methods of designing/developing discussed include various Systematic Evolution of Ligands by Exponential Enrichment (SELEX) procedures, in silico approaches, and non-SELEX methods for aptamers, and genetic engineering methods such as homologous recombination, Bacteriophage Recombineering of Electroporated DNA (BRED), Bacteriophage Recombineering with Infectious Particles (BRIP), and genome rebooting for bacteriophage. For biological vectors, methods such as alternate splicing, multiple promoters, internal ribosomal entry site, CRISPR-Cas9 system and Cre recombinase mediated recombination were used to design viral vectors, while non-viral vectors like exosomes are generated through parental cell-based direct engineering. Besides that, we also discussed the pros and cons, and applications of each design molecule in directing stem cell differentiation to illustrate their great potential in stem cells research. Finally, we highlighted some safety and efficacy concerns to be considered for future studies.

Wheat ESCRT-III protein TaSAL1 regulates male gametophyte transmission and controls tillering and heading date

Charged multivesicular protein 1 (CHMP1) is a member of the endosomal sorting complex required for transport-III (ESCRT-III) complex that targets membrane localized signaling receptors to intralumenal vesicles in the multivesicular body of the endosome and eventually to the lysosome for degradation. Although CHMP1 plays roles in various plant growth and development processes, little is known about its function in wheat. In this study, we systematically analysed the members of the ESCRT-III complex in wheat (Triticum aestivum) and found that their orthologs were highly conserved in eukaryotic evolution. We identified CHMP1 homologous genes, TaSAL1s, and found that they were constitutively expressed in wheat tissues and essential for plant reproduction. Subcellular localization assays showed these proteins aggregated with and closely associated with the endoplasmic reticulum when ectopically expressed in tobacco leaves. We also found these proteins were toxic and caused leaf death. A genetic and reciprocal cross analysis revealed that TaSAL1 leads to defects in male gametophyte biogenesis. Moreover, phenotypic and metabolomic analysis showed that TaSAL1 may regulate tillering and heading date through phytohormone pathways. Overall, our results highlight the role of CHMP1 in wheat, particularly in male gametophyte biogenesis, with implications for improving plant growth and developing new strategies for plant breeding and genetic engineering.

The human AAA-ATPase VPS4A isoform and its co-factor VTA1 have a unique function in regulating mammalian cytokinesis abscission

Mutations in the human AAA-ATPase VPS4 isoform, VPS4A, cause severe neurodevelopmental defects and congenital dyserythropoietic anemia (CDA). VPS4 is a crucial component of the endosomal sorting complex required for transport (ESCRT) system, which drives membrane remodeling in numerous cellular processes, including receptor degradation, cell division, and neural pruning. Notably, while most organisms encode for a single VPS4 gene, human cells have 2 VPS4 paralogs, namely VPS4A and VPS4B, but the functional differences between these paralogs is mostly unknown. Here, we set out to investigate the role of the human VPS4 paralogs in cytokinetic abscission using a series of knockout cell lines. We found that VPS4A and VPS4B hold both overlapping and distinct roles in abscission. VPS4A depletion resulted in a more severe abscission delay than VPS4B and was found to be involved in earlier stages of abscission. Moreover, VPS4A and a monomeric-locked VPS4A mutant bound the abscission checkpoint proteins CHMP4C and ANCHR, while VPS4B did not, indicating a regulatory role for the VPS4A isoform in abscission. Depletion of VTA1, a co-factor of VPS4, disrupted VPS4A-ANCHR interactions and accelerated abscission, suggesting that VTA1 is also involved in the abscission regulation. Our findings reveal a dual role for VPS4A in abscission, one that is canonical and can be compensated by VPS4B, and another that is regulatory and may be delivered by its monomeric form. These observations provide a potential mechanistic explanation for the neurodevelopmental defects and other related disorders reported in VPS4A-mutated patients with a fully functional VPS4B paralog.

A role for Vps13-mediated lipid transfer at the ER-endosome contact site in ESCRT-mediated sorting

Endosomes are specialized organelles that function in the secretory and endocytic protein sorting pathways. Endocytosed cell surface receptors and transporters destined for lysosomal degradation are sorted into intraluminal vesicles (ILVs) at endosomes by endosomal sorting complexes required for transport (ESCRT) proteins. The endosomes (multivesicular bodies, MVBs) then fuse with the lysosome. During endosomal maturation, the number of ILVs increases, but the size of endosomes does not decrease despite the consumption of the limiting membrane during ILV formation. Vesicle-mediated trafficking is thought to provide lipids to support MVB biogenesis. However, we have uncovered an unexpected contribution of a large bridge-like lipid transfer protein, Vps13, in this process. Here, we reveal that Vps13-mediated lipid transfer at ER-endosome contact sites is required for the ESCRT pathway. We propose that Vps13 may play a critical role in supplying lipids to the endosome, ensuring continuous ESCRT-mediated sorting during MVB biogenesis.

Identification of membrane curvature sensing motifs essential for VPS37A phagophore recruitment and autophagosome closure

VPS37A, an ESCRT-I complex component, is required for recruiting a subset of ESCRT proteins to the phagophore for autophagosome closure. However, the mechanism by which VPS37A is targeted to the phagophore remains obscure. Here, we demonstrate that the VPS37A N-terminal domain exhibits selective interactions with highly curved membranes, mediated by two membrane-interacting motifs within the disordered regions surrounding its Ubiquitin E2 variant-like (UEVL) domain. Site-directed mutations of residues in these motifs disrupt ESCRT-I localization to the phagophore and result in defective phagophore closure and compromised autophagic flux in vivo, highlighting their essential role during autophagy. In conjunction with the UEVL domain, we postulate that these motifs guide a functional assembly of the ESCRT machinery at the highly curved tip of the phagophore for autophagosome closure. These results advance the notion that the distinctive membrane architecture of the cup-shaped phagophore spatially regulates autophagosome biogenesis.