Release of extracellular membrane particles carrying the stem cell marker prominin-1 (CD133) from neural progenitors and other epithelial cells

The Impact of Glycosylation on the Functional Activity of CD133 and the Accuracy of Its Immunodetection

The membrane glycoprotein CD133 (prominin-1) is widely regarded as the main molecular marker of cancer stem cells, which are the most malignant cell subpopulation within the tumor, responsible for tumor growth and metastasis. For this reason, CD133 is considered a promising prognostic biomarker and molecular target for antitumor therapy. Under normal conditions, CD133 is present on the cell membrane in glycosylated form. However, in malignancies, altered glycosylation apparently leads to changes in the functional activity of CD133 and the availability of some of its epitopes for antibodies. This review focuses on CD133's glycosylation in human cells and its impact on the function of this glycoprotein. The association of CD133 with proliferation, differentiation, apoptosis, autophagy, epithelial-mesenchymal transition, the organization of plasma membrane protrusions and extracellular trafficking is discussed. In this review, particular attention is paid to the influence of CD133's glycosylation on its immunodetection. A list of commercially available and custom antibodies with their characteristics is provided. The available data indicate that the development of CD133-based biomedical technologies should include an assessment of CD133's glycosylation in each tumor type.

Analysis of small EV proteomes reveals unique functional protein networks regulated by VAP-A

Extracellular vesicles (EVs) influence cell phenotypes and functions via protein, nucleic acid, and lipid cargoes. EVs are heterogeneous, due to diverse biogenesis mechanisms that remain poorly understood. Our previous study revealed that the endoplasmic reticulum (ER) membrane contact site (MCS) linker protein vesicle associated protein associated protein A (VAP-A) drives biogenesis of a subset of RNA-enriched EVs. Here, we examine the protein content of VAP-A-regulated EVs. Using label-free proteomics, we identified down- and upregulated proteins in small EVs (SEVs) purified from VAP-A knockdown (KD) colon cancer cells. Gene set enrichment analysis (GSEA) of the data revealed protein classes that are differentially sorted to SEVs dependent on VAP-A. Search Tool for the Retrieval of Reciprocity Genes (STRING) protein-protein interaction network analysis of the RNA-binding protein (RBP) gene set identified several RNA functional machineries that are downregulated in VAP-A KD SEVs, including ribosome, spliceosome, mRNA surveillance, and RNA transport proteins. We also observed downregulation of other functionally interacting protein networks, including cadherin-binding, unfolded protein binding, and ATP-dependent proteins.

Prominin 1 and Tweety Homology 1 both induce extracellular vesicle formation

Prominin-1 (Prom1) is a five-transmembrane-pass integral membrane protein that associates with curved regions of the plasma membrane. Prom1 interacts with membrane cholesterol and actively remodels the plasma membrane. Membrane bending activity is particularly evident in photoreceptors, where Prom1 loss-of-function mutations cause failure of outer segment homeostasis, leading to cone-rod retinal dystrophy (CRRD). The Tweety Homology (Ttyh) protein family has been proposed to be homologous to Prominin, but it is not known whether Ttyh proteins have an analogous membrane-bending function. Here, we characterize the membrane-bending activity of human Prom1 and Ttyh1 in native bilayer membranes. We find that Prom1 and Ttyh1 both induce formation of extracellular vesicles (EVs) in cultured mammalian cells and that the EVs produced are physically similar. Ttyh1 is more abundant in EV membranes than Prom1 and produces EVs with membranes that are more tubulated than Prom1 EVs. We further show that Prom1 interacts more stably with membrane cholesterol than Ttyh1 and that this may contribute to membrane bending inhibition in Prom1 EVs. Intriguingly, a loss-of-function mutation in Prom1 associated with CRRD induces particularly stable cholesterol binding. These experiments provide mechanistic insight into Prominin function in CRRD and suggest that Prom and Ttyh belong to a single family of functionally related membrane-bending, EV-generating proteins.

Platelet-derived microparticles and their cargos: The past, present and future

All eukaryotic cells can secrete extracellular vesicles, which have a double-membrane structure and are important players in the intercellular communication involved in a variety of important biological processes. Platelets form platelet-derived microparticles (PMPs) in response to activation, injury, or apoptosis. This review introduces the origin, pathway, and biological functions of PMPs and their importance in physiological and pathological processes. In addition, we review the potential applications of PMPs in cancer, vascular homeostasis, thrombosis, inflammation, neural regeneration, biomarkers, and drug carriers to achieve targeted drug delivery. In addition, we comprehensively report on the origin, biological functions, and applications of PMPs. The clinical transformation, high heterogeneity, future development direction, and limitations of the current research on PMPs are also discussed in depth. Evidence has revealed that PMPs play an important role in cell-cell communication, providing clues for the development of PMPs as carriers for relevant cell-targeted drugs. The development history and prospects of PMPs and their cargos are explored in this guidebook.

Emerging roles of prominin-1 (CD133) in the dynamics of plasma membrane architecture and cell signaling pathways in health and disease

Prominin-1 (CD133) is a cholesterol-binding membrane glycoprotein selectively associated with highly curved and prominent membrane structures. It is widely recognized as an antigenic marker of stem cells and cancer stem cells and is frequently used to isolate them from biological and clinical samples. Recent progress in understanding various aspects of CD133 biology in different cell types has revealed the involvement of CD133 in the architecture and dynamics of plasma membrane protrusions, such as microvilli and cilia, including the release of extracellular vesicles, as well as in various signaling pathways, which may be regulated in part by posttranslational modifications of CD133 and its interactions with a variety of proteins and lipids. Hence, CD133 appears to be a master regulator of cell signaling as its engagement in PI3K/Akt, Src-FAK, Wnt/β-catenin, TGF-β/Smad and MAPK/ERK pathways may explain its broad action in many cellular processes, including cell proliferation, differentiation, and migration or intercellular communication. Here, we summarize early studies on CD133, as they are essential to grasp its novel features, and describe recent evidence demonstrating that this unique molecule is involved in membrane dynamics and molecular signaling that affects various facets of tissue homeostasis and cancer development. We hope this review will provide an informative resource for future efforts to elucidate the details of CD133's molecular function in health and disease.

Identification of novel blood-based extracellular vesicles biomarker candidates with potential specificity for traumatic brain injury in polytrauma patients

Objective

The goal of this study was to identify changes in extracellular vesicles (EV) surface proteins specific to traumatic brain injury (TBI), which could be used as a diagnostic and prognostic tool in polytrauma patients.

Summary Background Data

Known serum TBI-specific biomarkers (S100B, NSE, and GFAP), which can predict the severity and outcome of isolated TBI, lose their predictive value in the presence of additional extracranial injuries. Extracellular vesicles (EVs) are released from cells in response to various stimuli and carry specific cargo/surface molecules that could be used for tracking injury-responding cells.

Methods

EVs were isolated using size exclusion chromatography (SEC) from the plasma of two groups of patients (with isolated TBI, ISS≥16, AIShead≥4, n=10; and polytraumatized patients without TBI ISS≥16, AIShead=0, n=10) collected in the emergency room and 48 h after trauma. EVs' surface epitope expression was investigated using a neurospecific multiplex flow cytometry assay and compared with healthy controls (n=10). Three enrichments of EV epitopes found to be specific to TBI were validated by western blot.

Results

The expression of 10 EV epitopes differed significantly among the patient and control groups, and five of these epitopes (CD13, CD196, MOG, CD133, and MBP) were TBI-specific. The increased expression of CD196, CD13, and MOG-positive EVs was validated by western blot.

Conclusion

Our data showed that TBI is characterized by a significant increase of CD13, CD196, MOG, CD133, and MBP-positive EVs in patients' plasma. A high level of MOG-positive EVs negatively correlated with the Glasgow Coma Scale score at admission and could be an indicator of poor neurological status.

Emerging role of mesenchymal stem cells-derived extracellular vesicles in vascular dementia

Vascular dementia (VD) is a prevalent cognitive disorder among the elderly. Its pathological mechanism encompasses neuronal damage, synaptic dysfunction, vascular abnormalities, neuroinflammation, and oxidative stress, among others. In recent years, extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have garnered significant attention as an emerging therapeutic strategy. Current research indicates that MSC-derived extracellular vesicles (MSC-EVs) play a pivotal role in both the diagnosis and treatment of VD. Thus, this article delves into the recent advancements of MSC-EVs in VD, discussing the mechanisms by which EVs influence the pathophysiological processes of VD. These mechanisms form the theoretical foundation for their neuroprotective effect in VD treatment. Additionally, the article highlights the potential applications of EVs in VD diagnosis. In conclusion, MSC-EVs present a promising innovative treatment strategy for VD. With rigorous research and ongoing innovation, this concept can transition into practical clinical treatment, providing more effective options for VD patients.

Combination of blockade of endothelin signalling and compensation of IGF1 expression protects the retina from degeneration

Retinitis pigmentosa (RP) and macular dystrophy (MD) cause severe retinal dysfunction, affecting 1 in 4000 people worldwide. This disease is currently assumed to be intractable, because effective therapeutic methods have not been established, regardless of genetic or sporadic traits. Here, we examined a RP mouse model in which the Prominin-1 (Prom1) gene was deficient and investigated the molecular events occurring at the outset of retinal dysfunction. We extracted the Prom1-deficient retina subjected to light exposure for a short time, conducted single-cell expression profiling, and compared the gene expression with and without stimuli. We identified the cells and genes whose expression levels change directly in response to light stimuli. Among the genes altered by light stimulation, Igf1 was decreased in rod photoreceptor cells and astrocytes under the light-stimulated condition. Consistently, the insulin-like growth factor (IGF) signal was weakened in light-stimulated photoreceptor cells. The recovery of Igf1 expression with the adeno-associated virus (AAV) prevented photoreceptor cell death, and its treatment in combination with the endothelin receptor antagonist led to the blockade of abnormal glial activation and the promotion of glycolysis, thereby resulting in the improvement of retinal functions, as assayed by electroretinography. We additionally demonstrated that the attenuation of mammalian/mechanistic target of rapamycin (mTOR), which mediates IGF signalling, leads to complications in maintaining retinal homeostasis. Together, we propose that combinatorial manipulation of distinct mechanisms is useful for the maintenance of the retinal condition.

Extracellular lipidosomes containing lipid droplets and mitochondria are released during melanoma cell division

BACKGROUND

The incidence of melanoma is increasing worldwide. Since metastatic melanoma is highly aggressive, it is important to decipher all the biological aspects of melanoma cells. In this context, we have previously shown that metastatic FEMX-I melanoma cells release small (< 150 nm) extracellular vesicles (EVs) known as exosomes and ectosomes containing the stem (and cancer stem) cell antigenic marker CD133. EVs play an important role in intercellular communication, which could have a micro-environmental impact on surrounding tissues.

RESULTS

We report here a new type of large CD133+ EVs released by FEMX-I cells. Their sizes range from 2 to 6 µm and they contain lipid droplets and mitochondria. Real-time video microscopy revealed that these EVs originate from the lipid droplet-enriched cell extremities that did not completely retract during the cell division process. Once released, they can be taken up by other cells. Silencing CD133 significantly affected the cellular distribution of lipid droplets, with a re-localization around the nuclear compartment. As a result, the formation of large EVs containing lipid droplets was severely compromised.

CONCLUSION

Given the biochemical effect of lipid droplets and mitochondria and/or their complexes on cell metabolism, the release and uptake of these new large CD133+ EVs from dividing aggressive melanoma cells can influence both donor and recipient cells, and therefore impact melanoma growth and dissemination.

Biomolecules to Biomarkers? U87MG Marker Evaluation on the Path towards Glioblastoma Multiforme Pathogenesis

The heterogeneity of the glioma subtype glioblastoma multiforme (GBM) challenges effective neuropathological treatment. The reliance on in vitro studies and xenografted animal models to simulate human GBM has proven ineffective. Currently, a dearth of knowledge exists regarding the applicability of cell line biomolecules to the realm of GBM pathogenesis. Our study's objectives were to address this preclinical issue and assess prominin-1, ICAM-1, PARTICLE and GAS5 as potential GBM diagnostic targets. The methodologies included haemoxylin and eosin staining, immunofluorescence, in situ hybridization and quantitative PCR. The findings identified that morphology correlates with malignancy in GBM patient pathology. Immunofluorescence confocal microscopy revealed prominin-1 in pseudo-palisades adjacent to necrotic foci in both animal and human GBM. Evidence is presented for an ICAM-1 association with degenerating vasculature. Significantly elevated nuclear PARTICLE expression from in situ hybridization and quantitative PCR reflected its role as a tumor activator. GAS5 identified within necrotic GBM validated this potential prognostic biomolecule with extended survival. Here we present evidence for the stem cell marker prominin-1 and the chemotherapeutic target ICAM-1 in a glioma animal model and GBM pathology sections from patients that elicited alternative responses to adjuvant chemotherapy. This foremost study introduces the long non-coding RNA PARTICLE into the context of human GBM pathogenesis while substantiating the role of GAS5 as a tumor suppressor. The validation of GBM biomarkers from cellular models contributes to the advancement towards superior detection, therapeutic responders and the ultimate attainment of promising prognoses for this currently incurable brain cancer.

Recommendations for reproducibility of cerebrospinal fluid extracellular vesicle studies

Cerebrospinal fluid (CSF) is a clear, transparent fluid derived from blood plasma that protects the brain and spinal cord against mechanical shock, provides buoyancy, clears metabolic waste and transports extracellular components to remote sites in the brain. Given its contact with the brain and the spinal cord, CSF is the most informative biofluid for studies of the central nervous system (CNS). In addition to other components, CSF contains extracellular vesicles (EVs) that carry bioactive cargoes (e.g., lipids, nucleic acids, proteins), and that can have biological functions within and beyond the CNS. Thus, CSF EVs likely serve as both mediators of and contributors to communication in the CNS. Accordingly, their potential as biomarkers for CNS diseases has stimulated much excitement for and attention to CSF EV research. However, studies on CSF EVs present unique challenges relative to EV studies in other biofluids, including the invasive nature of CSF collection, limited CSF volumes and the low numbers of EVs in CSF as compared to plasma. Here, the objectives of the International Society for Extracellular Vesicles CSF Task Force are to promote the reproducibility of CSF EV studies by providing current reporting and best practices, and recommendations and reporting guidelines, for CSF EV studies. To accomplish this, we created and distributed a world-wide survey to ISEV members to assess methods considered 'best practices' for CSF EVs, then performed a detailed literature review for CSF EV publications that was used to curate methods and resources. Based on responses to the survey and curated information from publications, the CSF Task Force herein provides recommendations and reporting guidelines to promote the reproducibility of CSF EV studies in seven domains: (i) CSF Collection, Processing, and Storage; (ii) CSF EV Separation/Concentration; (iii) CSF EV Size and Number Measurements; (iv) CSF EV Protein Studies; (v) CSF EV RNA Studies; (vi) CSF EV Omics Studies and (vii) CSF EV Functional Studies.

Can CD133 Be Regarded as a Prognostic Biomarker in Oncology: Pros and Cons

The CD133 cell membrane glycoprotein, also termed prominin-1, is expressed on some of the tumor cells of both solid and blood malignancies. The CD133-positive tumor cells were shown to exhibit higher proliferative activity, greater chemo- and radioresistance, and enhanced tumorigenicity compared to their CD133-negative counterparts. For this reason, CD133 is regarded as a potential prognostic biomarker in oncology. The CD133-positive cells are related to the cancer stem cell subpopulation in many types of cancer. Recent studies demonstrated the involvement of CD133 in the regulation of proliferation, autophagy, and apoptosis in cancer cells. There is also evidence of its participation in the epithelial-mesenchymal transition associated with tumor progression. For a number of malignant tumor types, high CD133 expression is associated with poor prognosis, and the prognostic significance of CD133 has been confirmed in a number of meta-analyses. However, some published papers suggest that CD133 has no prognostic significance or even demonstrate a certain correlation between high CD133 levels and a positive prognosis. This review summarizes and discusses the existing evidence for and against the prognostic significance of CD133 in cancer. We also consider possible reasons for conflicting findings from the studies of the clinical significance of CD133.

Effect of radiotherapy on the DNA cargo and cellular uptake mechanisms of extracellular vesicles

In the past decades, plenty of evidence has gathered pointing to the role of extracellular vesicles (EVs) secreted by irradiated cells in the development of radiation-induced non-targeted effects. EVs are complex natural structures composed of a phospholipid bilayer which are secreted by virtually all cells and carry bioactive molecules. They can travel certain distances in the body before being taken up by recipient cells. In this review we discuss the role and fate of EVs in tumor cells and highlight the importance of DNA specimens in EVs cargo in the context of radiotherapy. The effect of EVs depends on their cargo, which reflects physiological and pathological conditions of donor cell types, but also depends on the mode of EV uptake and mechanisms involved in the route of EV internalization. While the secretion and cargo of EVs from irradiated cells has been extensively studied in recent years, their uptake is much less understood. In this review, we will focus on recent knowledge regarding the EV uptake of cancer cells and the effect of radiation in this process.

A meta-analysis of neurogenic exosomes in the diagnosis of Alzheimer's disease

Background

Alzheimer's disease (AD) is an irreversible and difficult-to-treat neurodegenerative disease. It is necessary to search for reliable biomarkers for the early diagnosis of AD in a timely and effective manner in high-risk or preclinical AD populations. Studies have shown that neurogenic exosomes in the blood can be effectively used as biomarkers for AD.

Objective

In this meta-analysis, we aimed to find reliable biomarkers (Aβ42, T-tau, and P-tau181 in peripheral blood neurogenic exosomes) for the early diagnosis of AD to provide theoretical support for the early diagnosis of high-risk or preclinical AD populations.

Methods

By searching the literature database, relevant studies on AD diagnostic markers were collected. The study period was from April 1, 2012, to April 1, 2022. The average concentrations of Aβ42, T-tau, and P-tau181 in the exosomes of the AD group and healthy control group were compared using RevMan 5.3 software.

Results

A total of 13 studies were screened, including 842 subjects. Meta-analysis showed that the combined SMD value of neurogenic exosome Aβ42 was 1.70 (95% CI = [1.20,2.20], Z = 6.69, P < 0.05). The combined SMD value of T-tau was 1.02 (95% CI = [0.27,1.77], Z = 2.67, P < 0.05). The combined SMD value of P-tau181 was 1.75 (95% CI = [1.16, 2.35], Z = 5.75, P < 0.05). The levels of neurogenic exosomes Aβ42, T-tau, and P-tau181 in AD patients were significantly higher than those in healthy controls.

Conclusion

Aβ42, T-tau, and P-tau181 in blood neurogenic exosomes can be effectively used as biomarkers for AD and can be applied in the diagnosis, screening, prognosis prediction and disease monitoring of AD.

Analysis of small EV proteomes reveals unique functional protein networks regulated by VAP-A

Extracellular vesicles (EVs) influence cell phenotypes and functions via protein, nucleic acid and lipid cargoes. EVs are heterogeneous, due to diverse biogenesis mechanisms that remain poorly understood. Our previous study revealed that the endoplasmic reticulum (ER) membrane contact site (MCS) linker protein VAP-A drives biogenesis of a subset of RNA-enriched EVs. Here, we examine the protein content of VAP-A-regulated EVs. Using label-free proteomics, we identified down- and up-regulated proteins in sEVs purified from VAP-A knockdown (KD) colon cancer cells. Gene set enrichment analysis (GSEA) of the data revealed protein classes that are differentially sorted to SEVs dependent on VAP-A. STRING protein-protein interaction network analysis of the RNA-binding protein (RBP) gene set identified several RNA functional machineries that are downregulated in VAP-A KD EVs, including ribosome, spliceosome, mRNA surveillance, and RNA transport proteins. We also observed downregulation of other functionally interacting protein networks, including cadherin-binding, unfolded protein binding, and ATP-dependent proteins.

Context-specific regulation of extracellular vesicle biogenesis and cargo selection

To coordinate, adapt and respond to biological signals, cells convey specific messages to other cells. An important aspect of cell-cell communication involves secretion of molecules into the extracellular space. How these molecules are selected for secretion has been a fundamental question in the membrane trafficking field for decades. Recently, extracellular vesicles (EVs) have been recognized as key players in intercellular communication, carrying not only membrane proteins and lipids but also RNAs, cytosolic proteins and other signalling molecules to recipient cells. To communicate the right message, it is essential to sort cargoes into EVs in a regulated and context-specific manner. In recent years, a wealth of lipidomic, proteomic and RNA sequencing studies have revealed that EV cargo composition differs depending upon the donor cell type, metabolic cues and disease states. Analyses of distinct cargo 'fingerprints' have uncovered mechanistic linkages between the activation of specific molecular pathways and cargo sorting. In addition, cell biology studies are beginning to reveal novel biogenesis mechanisms regulated by cellular context. Here, we review context-specific mechanisms of EV biogenesis and cargo sorting, focusing on how cell signalling and cell state influence which cellular components are ultimately targeted to EVs.

The human neurosecretome: extracellular vesicles and particles (EVPs) of the brain for intercellular communication, therapy, and liquid-biopsy applications

Emerging evidence suggests that brain derived extracellular vesicles (EVs) and particles (EPs) can cross blood-brain barrier and mediate communication among neurons, astrocytes, microglial, and other cells of the central nervous system (CNS). Yet, a complete understanding of the molecular landscape and function of circulating EVs & EPs (EVPs) remain a major gap in knowledge. This is mainly due to the lack of technologies to isolate and separate all EVPs of heterogeneous dimensions and low buoyant density. In this review, we aim to provide a comprehensive understanding of the neurosecretome, including the extracellular vesicles that carry the molecular signature of the brain in both its microenvironment and the systemic circulation. We discuss the biogenesis of EVPs, their function, cell-to-cell communication, past and emerging isolation technologies, therapeutics, and liquid-biopsy applications. It is important to highlight that the landscape of EVPs is in a constant state of evolution; hence, we not only discuss the past literature and current landscape of the EVPs, but we also speculate as to how novel EVPs may contribute to the etiology of addiction, depression, psychiatric, neurodegenerative diseases, and aid in the real time monitoring of the "living brain". Overall, the neurosecretome is a concept we introduce here to embody the compendium of circulating particles of the brain for their function and disease pathogenesis. Finally, for the purpose of inclusion of all extracellular particles, we have used the term EVPs as defined by the International Society of Extracellular Vesicles (ISEV).

Involvement of a novel cAMP signaling mediator for beige adipogenesis

BACKGROUND

Exposure to cold temperature stimulates the sympathetic nervous system that activates β-adrenergic receptor signals in brown and beige adipocytes, leading to the induction of adaptive thermogenesis in mammals. Prominin-1 (PROM1) is a pentaspan transmembrane protein that is widely identified as a marker for stem cells, although the role of this protein as a regulator of many intracellular signaling cascades has been recently delineated. The main focus of the current study is to identify the previously unknown role of PROM1 in beige adipogenesis and adaptive thermogenesis.

METHODS

Prom1 whole body knockout (Prom1 KO) mice, Prom1 adipogenic progenitor (AP) cell-specific knockout (Prom1 APKO) mice and Prom1 adipocyte-specific knockout (Prom1 AKO) mice were constructed and were subject for the induction of adaptive thermogenesis. The effect of systemic Prom1 depletion was evaluated by hematoxylin and eosin staining, immunostaining, and biochemical analysis in vivo. Flow cytometric analysis was performed to determine the identity of PROM1-expressing cell types, and the resultant cells were subject to beige adipogenesis in vitro. The potential role of PROM1 and ERM in cAMP signaling was also assessed in undifferentiated AP cells in vitro. Finally, the specific effect of Prom1 depletion on AP cell or mature adipocytes on adaptive thermogenesis was evaluated by hematoxylin and eosin staining, immunostaining, and biochemical analysis in vivo.

RESULTS

Prom1 KO mice displayed an impairment in cold- or β3-adrenergic agonist-induced adaptive thermogenesis in subcutaneous adipose tissues (SAT) but not in brown adipose tissues (BAT). By fluorescence-activated cell sorting (FACS) analysis, we identified that PROM1 positive cells are enriched in PDGFRα⁺Sca1⁺ AP cells from SAT. Interestingly, Prom1 knockout stromal vascular fractions showed reduced PDGFRα expression, suggesting a role of PROM1 in beige adipogenic potential. Indeed, we found that Prom1-deficient AP cells from SAT showed reduced potential for beige adipogenesis. Furthermore, AP cell-specific depletion of Prom1, but not adipocyte-specific depletion of Prom1, displayed defects in adaptive thermogenesis as evidenced by resistance to cold-induced browning of SAT and dampened energy expenditure in mice.

CONCLUSION

We found that PROM1 positive AP cells are essential for the adaptive thermogenesis by ensuing stress-induced beige adipogenesis. Identification of PROM1 ligand might be useful in the activation of thermogenesis that could be potentially beneficial in combating obesity.

PROM1-mediated cell signal transduction in cancer stem cells and hepatocytes

Prominin-1 (PROM1), also called CD133, is a penta-span transmembrane protein that is localized in membrane protrusions, such as microvilli and filopodia. It is known to be expressed in cancer stem cells and various progenitor cells of bone marrow, liver, kidney, and intestine. Accumulating evidence has revealed that PROM1 has multiple functions in various organs, such as eye, tooth, peripheral nerve, and liver, associating with various molecular protein partners. PROM1 regulates PKA-induced gluconeogenesis, TGFβ-induced fibrosis, and IL-6-induced regeneration in the liver, associating with Radixin, SMAD7, and GP130, respectively. In addition, PROM1 is necessary to maintain cancer stem cell properties by activating PI3K and β-Catenin. PROM1-deficienct mice also show distinct phenotypes in eyes, brain, peripheral nerves, and tooth. Here, we discuss recent findings of PROM1-mediated signal transduction. [BMB Reports 2023; 56(2): 65-70].

The choroid plexus: a missing link in our understanding of brain development and function

Studies of the choroid plexus lag behind those of the more widely known blood-brain barrier, despite a much longer history. This review has two overall aims. The first is to outline long-standing areas of research where there are unanswered questions, such as control of cerebrospinal fluid (CSF) secretion and blood flow. The second aim is to review research over the past 10 years where the focus has shifted to the idea that there are choroid plexuses located in each of the brain's ventricles that make specific contributions to brain development and function through molecules they generate for delivery via the CSF. These factors appear to be particularly important for aspects of normal brain growth. Most research carried out during the twentieth century dealt with the choroid plexus, a brain barrier interface making critical contributions to the composition and stability of the brain's internal environment throughout life. More recent research in the twenty-first century has shown the importance of choroid plexus-generated CSF in neurogenesis, influence of sex and other hormones on choroid plexus function, and choroid plexus involvement in circadian rhythms and sleep. The advancement of technologies to facilitate delivery of brain-specific therapies via the CSF to treat neurological disorders is a rapidly growing area of research. Conversely, understanding the basic mechanisms and implications of how maternal drug exposure during pregnancy impacts the developing brain represents another key area of research.

Applications of Extracellular Vesicles in Nervous System Disorders: An Overview of Recent Advances

Diseases affecting the brain and spinal cord fall under the umbrella term "central nervous system disease". Most medications used to treat or prevent chronic diseases of the central nervous system cannot cross the blood-brain barrier (BBB) and hence cannot reach their intended target. Exosomes facilitate cellular material movement and signal transmission. Exosomes can pass the blood-brain barrier because of their tiny size, high delivery efficiency, minimal immunogenicity, and good biocompatibility. They enter brain endothelial cells via normal endocytosis and reverse endocytosis. Exosome bioengineering may be a method to produce consistent and repeatable isolation for clinical usage. Because of their tiny size, stable composition, non-immunogenicity, non-toxicity, and capacity to carry a wide range of substances, exosomes are indispensable transporters for targeted drug administration. Bioengineering has the potential to improve these aspects of exosomes significantly. Future research into exosome vectors must focus on redesigning the membrane to produce vesicles with targeting abilities to increase exosome targeting. To better understand exosomes and their potential as therapeutic vectors for central nervous system diseases, this article explores their basic biological properties, engineering modifications, and promising applications.

Extracellular Vesicles and Membrane Protrusions in Developmental Signaling

During embryonic development, cells communicate with each other to determine cell fate, guide migration, and shape morphogenesis. While the relevant secreted factors and their downstream target genes have been characterized extensively, how these signals travel between embryonic cells is still emerging. Evidence is accumulating that extracellular vesicles (EVs), which are well defined in cell culture and cancer, offer a crucial means of communication in embryos. Moreover, the release and/or reception of EVs is often facilitated by fine cellular protrusions, which have a history of study in development. However, due in part to the complexities of identifying fragile nanometer-scale extracellular structures within the three-dimensional embryonic environment, the nomenclature of developmental EVs and protrusions can be ambiguous, confounding progress. In this review, we provide a robust guide to categorizing these structures in order to enable comparisons between developmental systems and stages. Then, we discuss existing evidence supporting a role for EVs and fine cellular protrusions throughout development.

Removal of cellular protrusions

Cell-cell communications are central to a variety of physiological and pathological processes in multicellular organisms. Cells often rely on cellular protrusions to communicate with one another, which enable highly selective and efficient signaling within complex tissues. Owing to significant improvements in imaging techniques, identification of signaling protrusions has increased in recent years. These protrusions are structurally specialized for signaling and facilitate interactions between cells. Therefore, physical regulation of these structures must be key for the appropriate strength and pattern of signaling outcomes. However, the typical approaches for understanding signaling regulation tend to focus solely on changes in signaling molecules, such as gene expression, protein-protein interaction, and degradation. In this short review, we summarize the studies proposing the removal of different types of signaling protrusions-including cilia, neurites, MT (microtubule based)-nanotubes and microvilli-and discuss their mechanisms and significance in signaling regulation.

Release of VAMP5-positive extracellular vesicles by retinal Müller glia in vivo

Cell-cell interactions in the central nervous system are based on the release of molecules mediating signal exchange and providing structural and trophic support through vesicular exocytosis and the formation of extracellular vesicles. The specific mechanisms employed by each cell type in the brain are incompletely understood. Here, we explored the means of communication used by Müller cells, a type of radial glial cells in the retina, which forms part of the central nervous system. Using immunohistochemical, electron microscopic, and molecular analyses, we provide evidence for the release of distinct extracellular vesicles from endfeet and microvilli of retinal Müller cells in adult mice in vivo. We identify VAMP5 as a Müller cell-specific SNARE component that is part of extracellular vesicles and responsive to ischemia, and we reveal differences between the secretomes of immunoaffinity-purified Müller cells and neurons in vitro. Our findings suggest extracellular vesicle-based communication as an important mediator of cellular interactions in the retina.

Hypoxia-induced GLT8D1 promotes glioma stem cell maintenance by inhibiting CD133 degradation through N-linked glycosylation

Gliomas are the most aggressive primary brain tumors. However, no significant improvement in survival has been achieved with the addition of temozolomide (TMZ) or radiation as initial therapy, although many clinical efforts have been carried out to target various signaling pathways or putative driver mutations. Here, we report that glycosyltransferase 8 domain containing 1 (GLT8D1), induced by HIF-1α under a hypoxic niche, significantly correlates with a higher grade of glioma, and a worse clinical outcome. Depletion of GLT8D1 inhibits self-renewal of glioma stem cell (GSC) in vitro and represses tumor growth in glioma mouse models. GLT8D1 knockdown promotes cell cycle arrest at G2/M phase and cellular apoptosis with or without TMZ treatment. We reveal that GLT8D1 impedes CD133 degradation through the endosomal-lysosomal pathway by N-linked glycosylation and protein-protein interaction. Directly blocking the GLT8D1/CD133 complex formation by CD133N1~108 (referred to as FECD133), or inhibiting GLT8D1 expression by lercanidipine, suppresses Wnt/β-catenin signaling dependent tumorigenesis both in vitro and in patient-derived xenografts mouse model. Collectively, these findings offer mechanistic insights into how hypoxia promotes GLT8D1/CD133/Wnt/β-catenin signaling during glioma progression, and identify GLT8D1 as a potential therapeutic target in the future.

TRIM28 Is a Novel Regulator of CD133 Expression Associated with Cancer Stem Cell Phenotype

CD133 is an extensively studied marker of the most malignant tumor cell population, designated as cancer stem cells (CSCs). However, the function of this glycoprotein and its involvement in cell regulatory cascades are still poorly understood. Here we show a positive correlation between the level of CD133 plasma membrane expression and the proliferative activity of cells of the Caco-2, HT-29, and HUH7 cancer cell lines. Despite a substantial difference in the proliferative activities of cell populations with different levels of CD133 expression, transcriptomic and proteomic profiling revealed only minor distinctions between them. Nonetheless, a further in silico assessment of the differentially expressed transcripts and proteins revealed 16 proteins that could be involved in the regulation of CD133 expression; these were assigned ranks reflecting the apparent extent of their involvement. Among them, the TRIM28 transcription factor had the highest rank. The prominent role of TRIM28 in CD133 expression modulation was confirmed experimentally in the Caco2 cell line clones: the knockout, though not the knockdown, of the TRIM28 gene downregulated CD133. These results for the first time highlight an important role of the TRIM28 transcription factor in the regulation of CD133-associated cancer cell heterogeneity.

EV duty vehicles: Features and functions of ciliary extracellular vesicles

The primary cilium is a microtubule-based organelle that extends from a basal body at the surface of most cells. This antenna is an efficient sensor of the cell micro-environment and is instrumental to the proper development and homeostatic control of organs. Recent compelling studies indicate that, in addition to its role as a sensor, the primary cilium also emits signals through the release of bioactive extracellular vesicles (EVs). While some primary-cilium derived EVs are released through an actin-dependent ectocytosis and are called ectosomes (or large EVs, 350–500 nm), others originate from the exocytosis of multivesicular bodies and are smaller (small EVs, 50–100 nm). Ciliary EVs carry unique signaling factors, including protein markers and microRNAs (miRNAs), and participate in intercellular communication in different organism models. This review discusses the mechanism of release, the molecular features, and functions of EVs deriving from cilia, based on the existing literature.

Cancer Stem Cell Markers in Rhabdomyosarcoma in Children

(1) Background: The aim of the present study was to assess the cancer stem cell (CSC) markers CD24, CD44, CD133, and ALDH1A1 in rhabdomyosarcoma (RMS) in children and to define their prognostic role in this group of patients. (2) Methods: The study material was archival tissue specimens collected from 49 patients under 18 years of age and who had been diagnosed with RMS. Immunohistochemistry (IHC) was used to evaluate the expression of the selected CSC markers in the tumor tissue. Expression was evaluated using a semiquantitative IRS scale based on the one developed by Remmele and Stenger and was correlated with the clinical and pathomorphological parameters of prognostic importance in RMS. (3) Results: Expression of the selected CSC markers CD24, CD44, CD133, and ALDH1A1 was demonstrated in 83.7%, 55.1%, 81.6%, and 100% of the RMS patients, respectively. The expression of all of the assessed CSC markers was statistically significantly higher in the study group versus the control group. No significant correlation was found between the expression of the selected CSC markers and clinical and pathological prognostic factors that were analyzed. The expression of the CSC markers did not have a significant influence on RMS survival rates. (4) Conclusions: The results of the conducted study confirm the expression of selected CSC markers in rhabdomyosarcoma tissue in children. The study did not support the prognostic relevance of the expression of any of the assessed CSC markers. However, further studies are needed to fully understand the relevance of the selected CSC markers in RMS carcinogenesis.

Prominin 1 and Notch regulate ciliary length and dynamics in multiciliated cells of the airway epithelium

Differences in ciliary morphology and dynamics among multiciliated cells of the respiratory tract contribute to efficient mucociliary clearance. Nevertheless, little is known about how these phenotypic differences are established. We show that Prominin 1 (Prom1), a transmembrane protein widely used as stem cell marker, is crucial to this process. During airway differentiation, Prom1 becomes restricted to multiciliated cells, where it is expressed at distinct levels along the proximal-distal axis of the airways. Prom1 is induced by Notch in multiciliated cells, and Notch inactivation abolishes this gradient of expression. Prom1 was not required for multicilia formation, but when inactivated resulted in longer cilia that beat at a lower frequency. Disruption of Notch resulted in opposite effects and suggested that Notch fine-tunes Prom1 levels to regulate the multiciliated cell phenotype and generate diversity among these cells. This mechanism could contribute to the innate defense of the lung and help prevent pulmonary disease.

RBP-J deficiency promoted the proliferation and differentiation of CD133-positive cells in vitro and in vivo studies

Although Notch signaling pathway could control the proliferation and differentiation of neural stem cells (NSCs), it is largely unknown about the effect of Notch signaling pathway on the neurogenesis of CD133-positive cells. By using the primary cultured ependymal cells and the transgenic mouse, we found that CD133 immunoreactivity was exclusively localized in the ependymal layer of ventricles, moreover, most CD133-positive cells were co-labeled with Nestin. In addition, recombination signal binding protein J (RBP-J), a key nuclear effector of Notch signaling pathway, was highly active in CD133-positive cells. CD133-positive cells can differentiate into the immature and mature neurons, in particular, the number of CD133-positive cells differentiating into the immature and mature neurons was significantly increased following the deficiency or interference of RBP-J in vivo or in vitro. By using real-time qPCR and western blot, we found that RBP-J and Hes1 were down-regulated while Notch1 was up-regulated in the expression levels of mRNAs and proteins following the deficiency or interference of RBP-J. These results demonstrated RBP-J deficiency promoted the proliferation and differentiation of CD133-positive cells. Therefore, we speculated that RBP-J could maintain CD133-positive cells in the characteristics of NSCs possibly by regulating Notch1/RBP-J/Hes1 pathway. It will provide a novel molecular insight into the function of RBP-J, as well as facilitate a future investigation of CD133-positive cells with respect to their potential application in neurodegenerative disorder.

Regulation of Cell Delamination During Cortical Neurodevelopment and Implication for Brain Disorders

Cortical development is dependent on key processes that can influence apical progenitor cell division and progeny. Pivotal among such critical cellular processes is the intricate mechanism of cell delamination. This indispensable cell detachment process mainly entails the loss of apical anchorage, and subsequent migration of the mitotic derivatives of the highly polarized apical cortical progenitors. Such apical progenitor derivatives are responsible for the majority of cortical neurogenesis. Many factors, including transcriptional and epigenetic/chromatin regulators, are known to tightly control cell attachment and delamination tendency in the cortical neurepithelium. Activity of these molecular regulators principally coordinate morphogenetic cues to engender remodeling or disassembly of tethering cellular components and external cell adhesion molecules leading to exit of differentiating cells in the ventricular zone. Improper cell delamination is known to frequently impair progenitor cell fate commitment and neuronal migration, which can cause aberrant cortical cell number and organization known to be detrimental to the structure and function of the cerebral cortex. Indeed, some neurodevelopmental abnormalities, including Heterotopia, Schizophrenia, Hydrocephalus, Microcephaly, and Chudley-McCullough syndrome have been associated with cell attachment dysregulation in the developing mammalian cortex. This review sheds light on the concept of cell delamination, mechanistic (transcriptional and epigenetic regulation) nuances involved, and its importance for corticogenesis. Various neurodevelopmental disorders with defective (too much or too little) cell delamination as a notable etiological underpinning are also discussed.

Subgroups of Extracellular Vesicles: Can They Be Defined by "Labels?"

Extracellular vesicles (EVs) are a class of lipid bilayer membranes, containing lipids, nucleic acids (DNA and RNA), proteins, and other substances. They are produced by almost all types of cells and act as signaling intermediaries between cells and/or tissues through different mechanisms involving complex signals. EVs produced by each type of cells are composed of highly heterogeneous and inhomogeneous subgroups with different biological functions. Therefore, in the past few decades, researchers have tried to use different "labels" to define the subgroups of EVs, and explore the differences in them. However, a unified standard for defining the populations of EVs has not yet been established so far. In this study, we review and summarize the use of different "labels" to define subgroups of EVs.

Morphological and ultrastructural characterization of neurospheres spontaneously generated in the culture from sheep ovarian cortical cells

Neurospheres (NS) derived from adult stem cells of non-neural tissues represent a promising source of neural stem cells (NSCs) and neural progenitor cells (NPCs) for autologous cell therapy. Knowing the fine structure of NS cells is essential for characterizing them during differentiation or oncogenic transformation. NS are generated by culturing ovarian cortical cells (OCCs) under specific conditions. To establish whether these OCCs exhibited a similar morphophenotype as those from the central nervous system (CNS) reported in the literature, sheep OCCs were cultured for 21 days to generate NS. Expression levels of pluripotency (Nanog, octamer-binding transcription factor 4 [Oct4], and SRY-box transcription factor 2 [Sox2]) and NSCs/NPCs (nestin, paired box 6 [Pax6], and p75 neurotrophin receptor [P75NTR]) transcripts were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), the NSC/NPC antigens were immunolocalized, and structural and ultrastructural analyses were performed in OCC-NS on Days 10, 15, and 21 in culture. Spheroids expressed transcripts and antigens of pluripotency as well as NSCs/NPCs. Cells were arranged into an inner core, with frequent apoptotic and degenerative events, and a peripheral epithelial-like cover with abundant cytoplasmic organelles, apical microvilli, and filament bundles of cytoskeleton elements. Adherens junctions and apical tight and lateral loose interdigitations were found in peripheral cells that eventually lost apical-basal polarization, which might indicate their disengaging/aggregating from/to the NS. We can conclude that OCC-NS shares the most structural and ultrastructural characteristics with CNS-NS.

Microvilli-derived extracellular vesicles carry Hedgehog morphogenic signals for Drosophila wing imaginal disc development

Morphogens are secreted molecules that regulate and coordinate major developmental processes, such as cell differentiation and tissue morphogenesis. Depending on the mechanisms of secretion and the nature of their carriers, morphogens act at short and long range. We investigated the paradigmatic long-range activity of Hedgehog (Hh), a well-known morphogen, and its contribution to the growth and patterning of the Drosophila wing imaginal disc. Extracellular vesicles (EVs) contribute to Hh long-range activity; however, the nature, the site, and the mechanisms underlying the biogenesis of these vesicular carriers remain unknown. Here, through the analysis of mutants and a series of Drosophila RNAi-depleted wing imaginal discs using fluorescence and live-imaging electron microscopy, including tomography and 3D reconstruction, we demonstrate that microvilli of the wing imaginal disc epithelium are the site of generation of small EVs that transport Hh across the tissue. Further, we show that the Prominin-like (PromL) protein is critical for microvilli integrity. Together with actin cytoskeleton and membrane phospholipids, PromL maintains microvilli architecture that is essential to promote its secretory function. Importantly, the distribution of Hh to microvilli and its release via these EVs contribute to the proper morphogenesis of the wing imaginal disc. Our results demonstrate that microvilli-derived EVs are carriers for Hh long-range signaling in vivo. By establishing that members of the Prominin protein family are key determinants of microvilli formation and integrity, our findings support the view that microvilli-derived EVs conveying Hh may provide a means for exchanging signaling cues of high significance in tissue development and cancer.

The promise of exosome applications in treating central nervous system diseases

Exosomes (EXs), a type of extracellular vesicles, are secreted from virtually all types of cells. EXs serve as cell-to-cell communicators by conveying proteins and nucleic acids with regulatory functions. Increasing evidence shows that EXs are implicated in the pathogenesis of central nervous system (CNS) diseases. Moreover, EXs have recently been highlighted as a new promising therapeutic strategy for in vivo delivery of nucleotides and drugs. Studies have revealed that infusion of EXs elicits beneficial effects on the CNS injury animal models. As compared to cell-based therapy, EXs-based therapy for CNS diseases has unique advantages, opening a new path for neurological medicine. In this review, we summarized the current state of knowledge of EXs, the roles and applications of EXs as a viable pathological biomarker, and EX-based therapy for CNS diseases.

Extracellular vesicles: General features and usefulness in diagnosis and therapeutic management of colorectal cancer

In the world, among all type of cancers, colorectal cancer (CRC) is the third most commonly diagnosed in males and the second in females. In most of cases, (RP1) patients’ prognosis limitation with malignant tumors can be attributed to delayed diagnosis of the disease. Identification of patients with early-stage disease leads to more effective therapeutic interventions. Therefore, new screening methods and further innovative treatment approaches are mandatory as they may lead to an increase in progression-free and overall survival rates. For the last decade, the interest in extracellular vesicles (EVs) research has exponentially increased as EVs generation appears to be a universal feature of every cell that is strongly involved in many mechanisms of cell-cell communication either in physiological or pathological situations. EVs can cargo biomolecules, such as lipids, proteins, nucleic acids and generate transmission signal through the intercellular transfer of their content. By this mechanism, tumor cells can recruit and modify the adjacent and systemic microenvironment to support further invasion and dissemination. This review intends to cover the most recent literature on the role of EVs production in colorectal normal and cancer tissues. Specific attention is paid to the use of EVs for early CRC diagnosis, follow-up, and prognosis as EVs have come into the spotlight of research as a high potential source of ‘liquid biopsies’. The use of EVs as new targets or nanovectors as drug delivery systems for CRC therapy is also summarized.

Exploring the Serum Level of RE1 Silencing Transcription Factor in Alzheimer’s Disease

Objective The aim of this study was to evaluate the serum RE1 silencing transcription factor (REST) level in Alzheimer’s disease (AD), mild cognitive impairment (MCI), and elderly controls by using surface plasmon resonance (SPR) technology.

Materials and Methods In this case–control study of 133 subjects, 49 patients with AD, 49 patients with MCI, and 35 elderly controls were recruited. The REST protein concentrations were evaluated by SPR. The resonance unit for each sample was recorded and the concentration of serum REST of study group was derived from the standard curve. All the experiments were done in triplicates. Statistical analysis was done and p-value of < 0.05 was considered as statistically significant.

Results A significant difference was observed in the Montreal Cognitive Assessment score, Hindi Mental State Examination scale (HMSE) score education, disease duration, and gender among the groups. A significant (p>0.0001) difference in the duration of disease between AD and MCI was observed. It was observed that the mean concentration of serum REST was not significantly (p = 0.266) different among the groups.

Conclusion This study first time evaluated the serum levels of REST in AD, MCI and age-matched elderly controls. The rest levels were similar in all groups; however, it can provide a new direction to future blood-based biomarker studies of REST.

Lactobacillus rhamnosus reduces the cytotoxic effects of group B streptococcus on HeLa cells

Group B Streptococcus (GBS) is an opportunistic pathogen found in the vaginal tract and is a leading cause of preterm birth and neonatal illness. Aside from GBS, the vaginal tract is predominantly colonized by commensal Lactobacillus species that are thought to protect the vaginal tract from pathogens, including GBS. Studies that examined if, and how Lactobacilli modulate GBS pathogenicity remain limited. This study sought to investigate the potential protective role of Lactobacillus rhamnosus against GBS, using an in vitro model system. Immunofluorescence microscopy and Scanning Electron Microscopy (SEM) captured images of infected HeLa cells and were analyzed using the image analysis program ImageJ. Results indicate that GBS causes HeLa cell detachment unless L. rhamnosus is present. SEM images show that GBS reduces length and number of microvilli on HeLa cell surface, as well as size of secreted vesicles. L. rhamnosus partially inhibits GBS-dependent microvilli and vesicle disruption. GBS also disrupts HeLa cell F-actin fibers unless L. rhamnosus is present. These results reveal effects of GBS infection on the host cell cytoskeleton and implies a protective role of L. rhamnosus against GBS colonization.

Diverse plasma membrane protrusions act as platforms for extracellular vesicle shedding

Plasma membrane curvature is an important factor in the regulation of cellular phenotype and is critical for various cellular activities including the shedding of extracellular vesicles (EV). One of the most striking morphological features of cells is different plasma membrane-covered extensions supported by actin core such as filopodia and microvilli. Despite the various functions of these extensions are partially unexplained, they are known to facilitate many crucial cellular functions such as migration, adhesion, absorption, and secretion. Due to the rapid increase in the research activity of EVs, there is raising evidence that one of the general features of cellular plasma membrane protrusions is to act as specialized platforms for the budding of EVs. This review will focus on early observations and recent findings supporting this hypothesis, discuss the putative budding and shedding mechanisms of protrusion-derived EVs and their biological significance.

Microglia extracellular vesicles: focus on molecular composition and biological function

Extracellular vesicles (EVs) are a heterogeneous family of cell-derived lipid bounded vesicles comprising exosomes and microvesicles. They are potentially produced by all types of cells and are used as a cell-to-cell communication method that allows protein, lipid, and genetic material exchange. Microglia cells produce a large number of EVs both in resting and activated conditions, in the latter case changing their production and related biological effects. Several actions of microglia in the central nervous system are ascribed to EVs, but the molecular mechanisms by which each effect occurs are still largely unknown. Conflicting functions have been ascribed to microglia-derived EVs starting from the neuronal support and ending with the propagation of inflammation and neurodegeneration, confirming the crucial role of these organelles in tuning brain homeostasis. Despite the increasing number of studies reported on microglia-EVs, there is also a lot of fragmentation in the knowledge on the mechanism at the basis of their production and modification of their cargo. In this review, a collection of literature data about the surface and cargo proteins and lipids as well as the miRNA content of EVs produced by microglial cells has been reported. A special highlight was given to the works in which the EV molecular composition is linked to a precise biological function.

Non-codon Optimized PiggyBac Transposase Induces Developmental Brain Aberrations: A Call for in vivo Analysis

In this perspective article, we briefly review tools for stable gain-of-function expression to explore key fate determinants in embryonic brain development. As the piggyBac transposon system has the highest insert size, a seamless integration of the transposed sequence into the host genome, and can be delivered by transfection avoiding viral vectors causing an immune response, we explored its use in the murine developing forebrain. The original piggyBac transposase PBase or the mouse codon-optimized version mPB and the construct to insert, contained in the piggyBac transposon, were introduced by in utero electroporation at embryonic day 13 into radial glia, the neural stem cells, in the developing dorsal telencephalon, and analyzed 3 or 5 days later. When using PBase, we observed an increase in basal progenitor cells, often accompanied by folding aberrations. These effects were considerably ameliorated when using the piggyBac plasmid together with mPB. While size and strength of the electroporated region was not correlated to the aberrations, integration was essential and the positive correlation to the insert size implicates the frequency of transposition as a possible mechanism. We discuss this in light of the increase in transposing endogenous viral vectors during mammalian phylogeny and their role in neurogenesis and radial glial cells. Most importantly, we aim to alert the users of this system to the phenotypes caused by non-codon optimized PBase application in vivo.

Trends in the biological functions and medical applications of extracellular vesicles and analogues

Natural extracellular vesicles (EVs) play important roles in many life processes such as in the intermolecular transfer of substances and genetic information exchanges. Investigating the origins and working mechanisms of natural EVs may provide an understanding of life activities, especially regarding the occurrence and development of diseases. Additionally, due to their vesicular structure, EVs (in small molecules, nucleic acids, proteins, etc.) could act as efficient drug-delivery carriers. Herein, we describe the sources and biological functions of various EVs, summarize the roles of EVs in disease diagnosis and treatment, and review the application of EVs as drug-delivery carriers. We also assess the challenges and perspectives of EVs in biomedical applications.

Heat shock proteins and exosomes in cancer theranostics

Heat shock proteins (HSPs) are a superfamily of molecular chaperones that were discovered through their ability to be induced by different stresses including heat shock. Other than their function as chaperones in proteins homeostasis, HSPs have been shown to inhibit different forms of cell death and to participate in cell proliferation and differentiation processes. Because cancer cells have to rewire their metabolism, they require a high amount of these stress-inducible chaperones for their survival. Therefore, HSPs are unusually abundant in cancer cells where they have oncogene-like functions. In cancer, HSPs have been involved in the regulation of apoptosis, immune responses, angiogenesis, metastasis and treatment resistance. Recently, HSPs have been shown to be secreted through exosomes by cancer cells. These tumor-derived exosomes can be used as circulating markers: HSP-exosomes have been reported as biomarkers of cancer dissemination, response to therapy and/or patient outcome. A new range of functions, mostly in modulation of anticancer immune responses, have been described for these extracellular HSPs. In this review, we will describe those recently reported functions of HSP-exosomes that makes them both targets for anticancer therapeutics and biomarkers for the monitoring of the disease. We will also discuss their emerging interest in cancer vaccines.

The ependymal cell cytoskeleton in the normal and injured spinal cord of mice

The cytoskeleton of ependymal cells is fundamental to organize and maintain the normal architecture of the central canal (CC). However, little is known about the plasticity of cytoskeletal components after spinal cord injury. Here, we focus on the structural organization of the cytoskeleton of ependymal cells in the normal and injured spinal cord of mice (both females and males) using immunohistochemical and electron microscopy techniques. We found that in uninjured animals, the actin cytoskeleton (as revealed by phalloidin staining) was arranged following the typical pattern of polarized epithelial cells with conspicuous actin pools located in the apical domain of ependymal cells. Transmission electron microscopy images showed microvilli tufts, long cilia, and characteristic intercellular membrane specializations. After spinal cord injury, F-actin rearrangements paralleled by fine structural modifications of the apical domain of ependymal cells were observed. These changes involved disruptions of the apical actin pools as well as fine structural modifications of the microvilli tufts. When comparing the control and injured spinal cords, we also found modifications in the expression of vimentin and glial fibrillary acidic protein (GFAP). After injury, vimentin expression disappeared from the most apical domains of ependymal cells but the number of GFAP-expressing cells within the CC increased. As in other polarized epithelia, the plastic changes in the cytoskeleton may be critically involved in the reaction of ependymal cells following a traumatic injury of the spinal cord.

Critical Review of the Evolution of Extracellular Vesicles' Knowledge: From 1946 to Today

Extracellular vesicles (EVs) are a family of particles/vesicles present in blood and body fluids, composed of phospholipid bilayers that carry a variety of molecules that can mediate cell communication, modulating crucial cell processes such as homeostasis, induction/dampening of inflammation, and promotion of repair. Their existence, initially suspected in 1946 and confirmed in 1967, spurred a sharp increase in the number of scientific publications. Paradoxically, the increasing interest for EV content and function progressively reduced the relevance for a precise nomenclature in classifying EVs, therefore leading to a confusing scientific production. The aim of this review was to analyze the evolution of the progress in the knowledge and definition of EVs over the years, with an overview of the methodologies used for the identification of the vesicles, their cell of origin, and the detection of their cargo. The MISEV 2018 guidelines for the proper recognition nomenclature and ways to study EVs are summarized. The review finishes with a “more questions than answers” chapter, in which some of the problems we still face to fully understand the EV function and potential as a diagnostic and therapeutic tool are analyzed.

Combined bioscaffold with stem cells and exosomes can improve traumatic brain injury

The intricacy of the brain, along with the existence of blood brain barrier (BBB) does complicate the delivery of effective therapeutics through simple intravascular injection. Hence, an effective delivery mechanism of therapeutics in the event of either traumatic brain injury (TBI) or other brain injuries is needed. Stem cells can promote regeneration and repair injury. The usage of biomaterials and exosomes in transporting stem cells to target lesion sites has been suggested as a potential option. The combination of biomaterials with modified exosomes can help in transporting stem cells to injury sites, whiles also increasing their survival and promoting effective treatment. Herein, we review the current researches pertinent to biological scaffolds and exosomes in repairing TBI and present the current progress and new direction in the clinical setting. We begin with the role of bioscaffold in treating neuronal conditions, the effect of exosomes in injury, and conclude with the improvement of TBI via the employment of combined exosomes, bioscaffold and stem cells.

Hepatic stellate cells: current state and open questions

This review article summarizes 20 years of our research on hepatic stellate cells within the framework of two collaborative research centers CRC575 and CRC974 at the Heinrich Heine University. Over this period, stellate cells were identified for the first time as mesenchymal stem cells of the liver, and important functions of these cells in the context of liver regeneration were discovered. Furthermore, it was determined that the space of Disse - bounded by the sinusoidal endothelium and hepatocytes - functions as a stem cell niche for stellate cells. Essential elements of this niche that control the maintenance of hepatic stellate cells have been identified alongside their impairment with age. This article aims to highlight previous studies on stellate cells and critically examine and identify open questions and future research directions.