Project description:The migrasome is a newly discovered organelle of migrating cells. Migrasomes play diverse physiological roles including mitochondrial quality control, lateral transfer of material between cells, and delivery of signaling molecules to spatially defined locations. The formation of migrasomes is dependent on tetraspanins, a group of membrane proteins containing four transmembrane domains, which form membrane microdomains named tetraspanin-enriched microdomains (TEMs). In this review, we will discuss the mechanisms for migrasome biogenesis, with a focus on the role of TEMs and the organizing principles underlying the formation of TEMs.
Project description:Migrasomes, enriched with signaling molecules such as chemokines, cytokines and angiogenic factors, play a pivotal role in the spatially defined delivery of these molecules, influencing critical physiological processes including organ morphogenesis and angiogenesis. The mechanism governing the accumulation of signaling molecules in migrasomes has been elusive. In this study, we show that secretory proteins, including signaling proteins, are transported into migrasomes by secretory carriers via both the constitutive and regulated secretion pathways. During cell migration, a substantial portion of these carriers is redirected to the rear of the cell and actively transported into migrasomes, driven by the actin-dependent motor protein Myosin-5a. Once at the migrasomes, these carriers fuse with the migrasome membrane through SNARE-mediated mechanisms. Inhibiting migrasome formation significantly reduces secretion, suggesting migrasomes as a principal secretion route in migrating cells. Our findings reveal a specialized, highly localized secretion paradigm in migrating cells, conceptually paralleling the targeted neurotransmitter release observed in neuronal systems.
Project description:Cell migration is a multi-step process that involves the coordinated action of signaling networks, cytoskeletal dynamics and vesicular trafficking, leading to protrusion and adhesion at the leading edge of cells and contraction and detachment at their rear. In a recent paper in Cell Research, Ma et al. describe the biogenesis of a new exosome-like organelle--named migrasomes--that derive from retraction fibers at the rear of migrating cells and their potential roles in inter-cellular signaling.
Project description:In the present study, we have documented a previously unrecognized membrane vesicles called “migrasomes” (M-mig) that originate from the filament-like nanotubes of macrophage.To characterize the signatures of macrophage migrasomes (M-mig) gene expression that might underlie M-mig-associated biological function. M0-mig, M1-mig, M2-mig and HG-mig genome-wide expression profiling was carried out by using SurePrint G3 Mouse GE V2.0 8X60K Microarrays (Design ID:074809, Agilent Technologies, USA). Total RNA was quantified by the NanoDrop ND-2000 (Thermo Scientific) and the RNA integrity was assessed using Agilent Bioanalyzer 2100 (Agilent Technologies). The sample labeling, microarray hybridization and washing were performed based on the manufacturer’s standard protocols. Briefly, total RNA was transcribed to double strand cDNA, then synthesized into cRNA and labeled with Cyanine-3-CTP. The labeled cRNAs were hybridized onto the microarray. After washing, the arrays were scanned by the Agilent Scanner G2505C (Agilent Technologies). For data analysis, Feature Extraction software (version10.7.1.1, Agilent Technologies) was used to analyze array images to get raw data. Genespring (version14.9, Agilent Technologies) were employed to finish the basic analysis with the raw data. To begin with, the raw data was normalized with the quantile algorithm. Differentially expressed genes were then identified through fold change. The threshold set for up- and down-regulated genes was a fold change>=2.0. Afterwards, GO analysis and KEGG analysis were applied to determine the roles of these differentially expressed mRNAs.
Project description:Breast milk is a complex and dynamic biological fluid and considered an essential source of nutrition in early life. In its composition, the proteins have a relevant biological activity and are related to the multiple benefits demonstrated when compared with artificial milks derived from cow's milk. Understanding human milk composition provides an important tool for health care providers toward the management of infant feeding and the establishment of breastfeeding. In this work, a new technique was developed to increase the knowledge of human milk, because many of the components remain unknown. To isolate minor proteins present in breast milk by using WGA lectin, breast milk was centrifuged to remove cells and separate the fat phase from the serum phase. The serum obtained was separated into two groups: control (n = 3; whole serum sample from mature milk) and WGA lectin (n = 3; sample processed with WGA lectin to isolate glycosylated proteins). The samples were analyzed by high-performance liquid chromatography coupled to mass spectrometry (HPLC/MS). A total of 84 different proteins were identified from all of the samples. In the WGA lectin group, 55 different proteins were isolated, 77% of which had biological functions related to the immune response. Of these proteins, there were eight WGA lectin group exclusives, and two had not previously been described in breast milk (polyubiquitin-B and POTE ankyrin domain family member F). Isolation by WGA lectin is a useful technique to detect minor proteins in breast milk and to identify proteins that could not be observed in whole serum.
Project description:In dynamic systems like the circulatory system, establishing localized cytokine gradients is challenging. Upon lipopolysaccharide (LPS) stimulation, we observed that monocytes release numerous migrasomes enriched with inflammatory cytokines, such as TNF-α and IL-6. These cytokines are transported into migrasomes via secretory carriers, leading to their immediate exocytosis or eventual release from detached migrasomes. We successfully isolated TNF-α and IL-6-enriched, monocyte-derived migrasomes from the blood of LPS-treated mice. Total secretion analysis revealed a substantial amount of TNF-α and IL-6 released in a migrasome-packaged form. Thus, detached, monocyte-derived migrasomes represent a type of extracellular vesicle highly enriched with cytokines. Physiologically, these cytokine-laden migrasomes rapidly accumulate at local sites of inflammation, effectively creating a concentrated source of cytokines. Our research uncovers novel mechanisms for cytokine release and delivery, providing new insights into immune response modulation.
Project description:Migrasomes are newly discovered cell organelles forming by local swelling of retraction fibers. The migrasome formation critically depends on tetraspanin proteins present in the retraction fiber membranes and is modulated by the membrane tension and bending rigidity. It remained unknown how and in which time sequence these factors are involved in migrasome nucleation, growth, and stabilization, and what are the possible intermediate stages of migrasome biogenesis. Here using live cell imaging and a biomimetic system for migrasomes and retraction fibers, we reveal that migrasome formation is a two-stage process. At the first stage, which in biomimetic system is mediated by membrane tension, local swellings largely devoid of tetraspanin 4 form on the retraction fibers. At the second stage, tetraspanin 4 molecules migrate toward and onto these swellings, which grow up to several microns in size and transform into migrasomes. This tetraspanin 4 recruitment to the swellings is essential for migrasome growth and stabilization. Based on these findings we propose that the major role of tetraspanin proteins is in stabilizing the migrasome structure, while the migrasome nucleation and initial growth stages can be driven by membrane mechanical stresses.
Project description:Migrasomes are organelles that are generated by migrating cells. Here we report the key role of neutrophil-derived migrasomes in haemostasis. We found that a large number of neutrophil-derived migrasomes exist in the blood of mice and humans. Compared with neutrophil cell bodies and platelets, these migrasomes adsorb and enrich coagulation factors on the surface. Moreover, they are highly enriched with adhesion molecules, which enable them to preferentially accumulate at sites of injury, where they trigger platelet activation and clot formation. Depletion of neutrophils, or genetic reduction of the number of these migrasomes, significantly decreases platelet plug formation and impairs coagulation. These defects can be rescued by intravenous injection of purified neutrophil-derived migrasomes. Our study reveals neutrophil-derived migrasomes as a previously unrecognized essential component of the haemostasis system, which may shed light on the cause of various coagulation disorders and open therapeutic possibilities.
Project description:BackgroundGenotyping assays often require substantial amounts of DNA. To overcome the problem of limiting amounts of available DNA, Whole Genome Amplification (WGA) methods have been developed. The multiple displacement amplification (MDA) method using Φ29 polymerase has become the preferred choice due to its high processivity and low error rate. However, the uniformity and fidelity of the amplification process across the genome has not been extensively characterized.ResultsTo assess amplification uniformity, we used array-based comparative genomic hybridization (aCGH) to evaluate DNA copy number variations (CNVs) in DNAs amplified by two MDA kits: GenomiPhi and REPLI-g. The Agilent Human CGH array containing nearly one million probes was used in this study together with DNAs from a normal subject and 2 cystic fibrosis (CF) patients. Each DNA sample was amplified 4 independent times and compared to its native unamplified DNA. Komogorov distances and Phi correlations showed a high consistency within each sample group. Less than 2% of the probes showed more than 2-fold CNV introduced by the amplification process. The two amplification kits, REPLI-g and GenomiPhi, generate very similar amplified DNA samples despite the differences between the unamplified and amplified DNA samples. The results from aCGH analysis indicated that there were no obvious CNVs in the CFTR gene region due to WGA when compared to unamplified DNA. This was confirmed by quantitative real-time PCR copy number assays at 10 locations within the CFTR gene. DNA sequencing analysis of a 2-kb region within the CFTR gene showed no mutations introduced by WGA.ConclusionThe relatively high uniformity and consistency of the WGA process, coupled with the low replication error rate, suggests that WGA DNA may be suitable for accurate genotyping. Regions of the genome that were consistently under-amplified were found to contain higher than average GC content. Because of the consistent differences between the WGA DNA and the native unamplified DNA, characterization of the genomic region of interest, as described here, will be necessary to ensure the reliability of genotyping results from WGA DNA.