Secretion Of Soluble Molecules Research Articles

Exosomes in Ageing and Motor Neurone Disease: Biogenesis, Uptake Mechanisms, Modifications in Disease and Uses in the Development of Biomarkers and Therapeutics.

Intercellular communication between neurons and their surrounding cells occurs through the secretion of soluble molecules or release of vesicles such as exosomes into the extracellular space, participating in brain homeostasis. Under neuro-degenerative conditions associated with ageing, such as amyotrophic lateral sclerosis (ALS), Alzheimer’s or Parkinson’s disease, exosomes are suspected to propagate toxic proteins. The topic of this review is the role of exosomes in ageing conditions and more specifically in ALS. Our current understanding of exosomes and exosome-related mechanisms is first summarized in a general sense, including their biogenesis and secretion, heterogeneity, cellular interaction and intracellular fate. Their role in the Central Nervous System (CNS) and ageing of the neuromotor system is then considered in the context of exosome-induced signaling. The review then focuses on exosomes in age-associated neurodegenerative disease. The role of exosomes in ALS is highlighted, and their use as potential biomarkers to diagnose and prognose ALS is presented. The therapeutic implications of exosomes for ALS are considered, whether as delivery vehicles, neurotoxic targets or as corrective drugs in and of themselves. A diverse set of mechanisms underpin the functional roles, both confirmed and potential, of exosomes, generally in ageing and specifically in motor neurone disease. Aspects of their contents, biogenesis, uptake and modifications offer many plausible routes towards the development of novel biomarkers and therapeutics.

Proteomic approaches to drive advances in helminth extracellular vesicle research

Helminths can interact with their hosts in many different ways, including through the secretion of soluble molecules (such as lipids, glycans and proteins) and extracellular vesicles (EVs). The field of helminth secreted EVs has significantly advanced in recent years, mainly due to the molecular characterisation of EV proteomes and research highlighting the potential of EVs and their constituent molecules in the diagnosis and control of parasitic infections. Despite these advancements, the lack of appropriate isolation and purification methods is impeding the discovery of suitable biomarkers for the differentiation of helminth EV populations. In the present review we offer our viewpoint on the different proteomic techniques and approaches that have been developed, as well as solutions to common pitfalls and challenges that could be applied to advance the study of helminth EVs.

Chronic peripheral inflammation: a possible contributor to neurodegenerative diseases.

The contribution of chronic peripheral inflammation to the pathogenesis of neurodegenerative diseases is an outstanding question. Sustained activation of the peripheral innate and adaptive immune systems occurs in the context of a broad array of disorders ranging from chronic infectious diseases to autoimmune and metabolic diseases. In addition, progressive systemic inflammation is increasingly recognized during aging. Peripheral immune cells could potentially modulate the cellular brain environment via the secretion of soluble molecules. There is an ongoing debate whether peripheral immune cells have the potential to migrate into the brain under certain permissive circumstances. In this perspective, we discuss the possible contribution of chronic peripheral inflammation to the pathogenesis of age-related neurodegenerative diseases with a focus on microglia, the resident immune cells of the brain parenchyma.

The Janus Face of NKT Cell Function in Autoimmunity and Infectious Diseases.

Natural killer T cells (NKT) are a subset of T lymphocytes bridging innate and adaptive immunity. These cells recognize self and microbial glycolipids bound to non-polymorphic and highly conserved CD1d molecules. Three NKT cell subsets, type I, II, and NKT-like expressing different antigen receptors (TCR) were described and TCR activation promotes intracellular events leading to specific functional activities. NKT can exhibit different functions depending on the secretion of soluble molecules and the interaction with other cell types. NKT cells act as regulatory cells in the defense against infections but, on the other hand, their effector functions can be involved in the pathogenesis of several inflammatory disorders due to their exposure to different microbial or self-antigens, respectively. A deep understanding of the biology and functions of type I, II, and NKT-like cells as well as their interplay with cell types acting in innate (neuthrophils, innate lymphoid cells, machrophages, and dendritic cells) and adaptive immunity (CD4+,CD8+, and double negative T cells) should be important to design potential immunotherapies for infectious and autoimmune diseases.

Mesenchymal Stem Cell-Derived Extracellular Vesicles as Mediators of Anti-Inflammatory Effects: Endorsement of Macrophage Polarization.

Mesenchymal Stem Cells (MSCs) are effective therapeutic agents enhancing the repair of injured tissues mostly through their paracrine activity. Increasing evidences show that besides the secretion of soluble molecules, the release of extracellular vesicles (EVs) represents an alternative mechanism adopted by MSCs. Since macrophages are essential contributors toward the resolution of inflammation, which has emerged as a finely orchestrated process, the aim of the present study was to carry out a detailed characterization of EVs released by human adipose derived‐MSCs to investigate their involvement as modulators of MSC anti‐inflammatory effects inducing macrophage polarization. The EV‐isolation method was based on repeated ultracentrifugations of the medium conditioned by MSC exposed to normoxic or hypoxic conditions (EVNormo and EVHypo). Both types of EVs were efficiently internalized by responding bone marrow‐derived macrophages, eliciting their switch from a M1 to a M2 phenotype. In vivo, following cardiotoxin‐induced skeletal muscle damage, EVNormo and EVHypo interacted with macrophages recruited during the initial inflammatory response. In injured and EV‐treated muscles, a downregulation of IL6 and the early marker of innate and classical activation Nos2 were concurrent to a significant upregulation of Arg1 and Ym1, late markers of alternative activation, as well as an increased percentage of infiltrating CD206pos cells. These effects, accompanied by an accelerated expression of the myogenic markers Pax7, MyoD, and eMyhc, were even greater following EVHypo administration. Collectively, these data indicate that MSC‐EVs possess effective anti‐inflammatory properties, making them potential therapeutic agents more handy and safe than MSCs. stem cells translational medicine 2017 Stem Cells Translational Medicine 2017;6:1018–1028

Abstract 2387: Pre-adipocytes promote myeloma homing to and growth in bone by secretion of soluble molecules

Abstract Multiple myeloma (MM) is a hematologic malignancy of plasma cells that thrives in and metastasizes throughout the bone marrow microenvironment. This microenvironment is host to a variety of cell types, including osteoblasts, osteoclasts and stromal cells, that become altered both at the primary tumor site and distant bone sites to support the growth and spread of MM cells. We recently reported that under certain conditions, such as when MM cells overexpress heparanase, MM cells redirect osteoblast progenitors from osteoblastogenesis towards adipogenesis. In addition, adipocytes naturally accumulate in aging marrow and adipocytes/adipose tissues have endocrine functions, secreting soluble factors such as adiponectin and leptin. Thus, adipocytes have the potential to be influential on MM cell behavior. Here, we hypothesized that adipocytes play an active role in MM progression through the secretion of soluble molecules that promote MM growth and metastasis to bone. To test this we used a co-culture system in which 3T3-L1 mouse pre-adipocytes or mature adipocytes were separated by a porous membrane from 5TGM1 mouse MM cells, allowing cross-talk by secreted molecules but not direct cell-cell contact. We then tested the motility of these “educated” 5TGM1 MM cells by migration assay. Somewhat surprisingly, we found that it was not mature adipocyte but pre-adipocyte education that enhanced the migration ability of MM cells compared to MM cells cultured alone. In a separate experiment, we injected 5TGM1 MM cells cultured alone, with pre-adipocytes, or with mature adipocytes into syngeneic C57BL/KaLwRij mice via tail vein and monitored progression by bioluminescent imaging. Total tumor burden was evaluated by IgG2bκ (a soluble marker of 5TGM1 MM cells) levels in mouse serum. Compared to MM cells cultured alone, those cultured with pre-adipocytes homed to the bone sooner and grew faster whereas those cultured with mature adipocytes showed no difference in homing or growth. To identify factors that may contribute to this apparent difference, pre-adipocyte or mature adipocyte conditioned media (CM) was analyzed using a cytokines/chemokines array. The results showed that pre-adipocytes secrete significantly larger quantities of molecules HGF, MCP-1 and IL-6 than mature adipocytes. Additional migration assays also confirmed that MM cells migrate more towards pre-adipocyte CM than to fresh media alone or mature adipocyte CM. In conclusion, this study demonstrates that pre-adipocytes, through the secretion of a variety of soluble molecules, promote a more aggressive phenotype in MM cells and contribute to MM growth and bone homing. Citation Format: Timothy N. Trotter, Patrick D. Rowan, Qianying Pan, Yang Yang. Pre-adipocytes promote myeloma homing to and growth in bone by secretion of soluble molecules. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2387. doi:10.1158/1538-7445.AM2015-2387

Classical and unconventional pathways of vesicular release in microglia

Emerging evidence indicates that activation of microglia, the immune cells of the brain, is strictly associated to both secretion of soluble molecules and release of extracellular membrane vesicles (EMVs) into the pericellular space. Through these processes, microglia heavily influence brain cell functions, either propagating inflammation and causing damage to neurons or playing a supportive, neuroprotective role. In this review, we highlight the emerging concepts related to vesicular mechanisms of secretion operating in microglial cells, with the aim of dissecting how microglia communicate with other cell types within the brain microenvironment in health and disease.

Advances in Mesenchymal Stromal Cell Properties

Human multipotent mesenchymal stromal cells (hMSCs) represent stem cells for non-hematopoietic tissues. The main interest in hMSCs is correlated with their ability to suppress the proliferation of CD8+ T lymphocytes regulating the transplantation rejection. Moreover, hMSCs are able to inhibit the differentiation of dendritic cells, the proliferation and antibody production of B lymphocytes and they stimulate the formation of regulatory T cells. The mechanisms at the basis of MSCs activity need cell-cell interaction and the secretion of soluble molecules into the microenvironment as hepatocyte growth factor, transforming growth factor-beta (TGF-beta), interleukin-10 and -2 (IL-10, IL-2), tumour necrosis factor-alpha (TNF-alpha), prostaglandin E2 (PGE2), indoleamine 2,3-dioxygenase (IDO) and Human Leukocyte Antigen (HLA)-G. Human multipotent mesenchymal stromal cells (hMSCs), first described by Friedenstein in '70 years (1) as non-hematopoietic cell precursors with osteogenic potential, represent stem cells for non- hematopoietic tissues (2). The International Society for Cellular Therapy (ISCT) reviewed the functional and immunophenotypic characteristics of stromal cells (3): they are plastic adherent cells that retain in vitro clonogenic potential, defined by the presence of the fibroblast-colony forming unit (CFU-F), capable of supporting hematopoiesis and having differentiation ability towards different cell types, as osteoblasts, chondrocytes, adipocytes, myocytes (4). In vitro and in vivo studies showed that hMSCs could differentiate into cells of non-mesodermal origin such as neurons, skin and gut epithelial cells, hepatocytes and pneumocytes (5). They express surface makers CD73, CD90, and CD105, and lack of expression of stem cell antigens CD34 and CD45 (3). hMSC were initially isolated and characterized from the bone marrow, but further researches identified other sources such as amniotic membrane, skin, adipose tissue, cord blood, fetal liver, placenta and synovium (6). Although these hMSC were thought to be the same general cell population regardless of the tissue source, recent data suggested a different hMSC gene expression profile on the basis of their tissue origin, indicating that hMSC tissue heterogeneity is biologically relevant. In the last years several studies demonstrated the peculiar immunological characteristics of hMSCs, as low antigenicity, caused by the decreased expression of classical HLA (human leukocyte antigen) class I molecules and the complete absence of HLA class II antigens and co-stimulatory molecules as CD80 (B7-1), CD86 (B7-2) and CD40, and high immune-modulatory ability. hMSCs suppress the proliferation of T lymphocytes (7), are resistant to the CD8+ T lymphocyte cytotoxicity, inhibit the differentiation of dendritic cells, the proliferation and antibody production of B lymphocytes and stimulate the formation of regulatory T cells. The mechanisms at the basis of hMSCs activity need cell-cell interaction and the secretion of soluble molecules in the micro-environment, as hepatocyte growth factor, transforming growth factor-beta (TGF-beta), interleukin-10 and -2 (IL-10, IL-2), tumour necrosis factor-alpha (TNF-alpha), prostaglandin E2 (PGE2), indoleamine 2,3-dioxygenase (IDO) (8) and HLA-G antigens (9).