Krisztina Buzas

Bio: Krisztina Buzas is an academic researcher from University of Szeged. The author has contributed to research in topics: Cytokine & Immune system. The author has an hindex of 15, co-authored 45 publications receiving 3379 citations. Previous affiliations of Krisztina Buzas include National Institutes of Health & Hungarian Academy of Sciences.

Biological properties of extracellular vesicles and their physiological functions

Abstract: In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.

Painful pathways induced by TLR stimulation of dorsal root ganglion neurons.

Abstract: We hypothesize that innate immune signals from infectious organisms and/or injured tissues may activate peripheral neuronal pain signals. In this study, we demonstrated that TLRs 3, 7, and 9 are expressed by human dorsal root ganglion neurons (DRGNs) and in cultures of primary mouse DRGNs. Stimulation of murine DRGNs with TLR ligands induced expression and production of proinflammatory chemokines and cytokines CCL5 (RANTES), CXCL10 (IP-10), IL-1α, IL-1β, and PGE 2 , which have previously been shown to augment pain. Further, TLR ligands upregulated the expression of a nociceptive receptor, transient receptor potential vanilloid type 1 (TRPV1), and enhanced calcium flux by TRPV1-expressing DRGNs. Using a tumor-induced temperature sensitivity model, we showed that in vivo administration of a TLR9 antagonist, known as a suppressive oligodeoxynucleotide, blocked tumor-induced temperature sensitivity. Taken together, these data indicate that stimulation of peripheral neurons by TLR ligands can induce nerve pain.

Importance of reverse signaling of the TNF superfamily in immune regulation

Abstract: TNF-related ligands (with the exception of lymphotoxin-α) are synthesized as type II transmembrane proteins, though many of them also have soluble forms. An increasing number of publications report that these 'ligands' behave as receptors, activating intracellular signaling pathways when interacting with cognate 'receptors' or agonistic antibodies. Most members of the TNF family and their receptors influence survival, proliferation, differentiation or activation of immune cells. The elicited 'reverse signals' also have significant importance. They proved to be involved in the activation of APCs, T and B cells, differentiation of osteoclasts and apoptosis of activated macrophages. They influence the balance between destructive immune response and tolerance. Several examples show that therapeutic manipulation of the reverse signal can help to treat malignancies as well as autoimmune disorders.

Comparison of circulating levels of interleukin-6 and tumor necrosis factor-alpha in hypertrophic cardiomyopathy and in idiopathic dilated cardiomyopathy.

Abstract: It is known from the literature that the circulating levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) are elevated in heart failure and idiopathic dilated cardiomyopathy (IDC). Few convincing data are available on the production of cytokines in hypertrophic cardiomyopathy (HC). The levels of circulating IL-6, the soluble form of the IL-6 receptor (sIL-6R), and TNF-alpha in 19 patients with HC, 31 patients with IDC, and 20 healthy subjects (control group) were examined and compared with their clinical parameters. The levels of TNF-alpha and circulating IL-6 proved to be elevated in the sera of patients with IDC. In contrast, the level of TNF-alpha was not elevated in HC, although the levels of IL-6 and sIL-6R were significantly higher than those in the sera of patients with IDC. Although elevated levels of IL-6 may correlate with the extent of left ventricular dysfunction in IDC, the markedly elevated IL-6 levels did not correlate with left ventricular function in HC. The markedly elevated TNF-alpha levels in IDC were associated with the elevated IL-6 levels, probably because of an inflammatory process and/or heart failure. In contrast, in HC, in which the New York Heart Association functional class was actually good, the even higher IL-6 and sIL-6R levels were not associated with a TNF-alpha elevation. In HC, the IL-6 and sIL-6R elevations were due to another mechanism, probably by way of the cardiotrophin-associated gp130 receptor. The sources of IL-6 production in HC are not clear yet.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Shedding light on the cell biology of extracellular vesicles.

Abstract: Extracellular vesicles are a heterogeneous group of cell-derived membranous structures comprising exosomes and microvesicles, which originate from the endosomal system or which are shed from the plasma membrane, respectively They are present in biological fluids and are involved in multiple physiological and pathological processes Extracellular vesicles are now considered as an additional mechanism for intercellular communication, allowing cells to exchange proteins, lipids and genetic material Knowledge of the cellular processes that govern extracellular vesicle biology is essential to shed light on the physiological and pathological functions of these vesicles as well as on clinical applications involving their use and/or analysis However, in this expanding field, much remains unknown regarding the origin, biogenesis, secretion, targeting and fate of these vesicles

Biological properties of extracellular vesicles and their physiological functions

Abstract: In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.

Proteomic comparison defines novel markers to characterize heterogeneous populations of extracellular vesicle subtypes.

Abstract: Extracellular vesicles (EVs) have become the focus of rising interest because of their numerous functions in physiology and pathology. Cells release heterogeneous vesicles of different sizes and intracellular origins, including small EVs formed inside endosomal compartments (i.e., exosomes) and EVs of various sizes budding from the plasma membrane. Specific markers for the analysis and isolation of different EV populations are missing, imposing important limitations to understanding EV functions. Here, EVs from human dendritic cells were first separated by their sedimentation speed, and then either by their behavior upon upward floatation into iodixanol gradients or by immuno-isolation. Extensive quantitative proteomic analysis allowing comparison of the isolated populations showed that several classically used exosome markers, like major histocompatibility complex, flotillin, and heat-shock 70-kDa proteins, are similarly present in all EVs. We identified proteins specifically enriched in small EVs, and define a set of five protein categories displaying different relative abundance in distinct EV populations. We demonstrate the presence of exosomal and nonexosomal subpopulations within small EVs, and propose their differential separation by immuno-isolation using either CD63, CD81, or CD9. Our work thus provides guidelines to define subtypes of EVs for future functional studies.

Specificities of secretion and uptake of exosomes and other extracellular vesicles for cell-to-cell communication.

Abstract: The ability of exosomes to transfer cargo from donor to acceptor cells, thereby triggering phenotypic changes in the latter, has generated substantial interest in the scientific community. However, the extent to which exosomes differ from other extracellular vesicles in terms of their biogenesis and functions remains ill-defined. Here, we discuss the current knowledge on the specificities of exosomes and other types of extracellular vesicles, and their roles as important agents of cell-to-cell communication.