SciCombinator

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Concept: TGF beta 1

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Dengue is the most prevalent human arbovirus disease in the world. Dengue infection has a large spectrum of clinical manifestations, from self-limited febrile illness to severe syndromes accompanied by bleeding and shock. Thrombocytopenia and vascular leak with altered cytokine profiles in plasma are features of severe dengue. Although monocytes have been recognized as important sources of cytokines in dengue, the contributions of platelet-monocyte interactions to inflammatory responses in dengue have not been addressed. Patients with dengue were investigated for platelet-monocyte aggregate formation. Platelet-induced cytokine responses by monocytes and underlying mechanisms were also investigated in vitro. We observed increased levels of platelet-monocyte aggregates in blood samples from patients with dengue, especially patients with thrombocytopenia and increased vascular permeability. Moreover, the exposure of monocytes from healthy volunteers to platelets from patients with dengue induced the secretion of the cytokines IL-1β, IL-8, IL-10 and MCP-1, whereas exposure to platelets from healthy volunteers only induced the secretion of MCP-1. In addition to the well-established modulation of monocyte cytokine responses by activated platelets through P-selectin binding, we found that interaction of monocytes with apoptotic platelets mediate IL-10 secretion through phosphatidylserine recognition in platelet-monocyte aggregates. Moreover, IL-10 secretion required platelet-monocyte contact but not phagocytosis. Together, our results demonstrate that activated and apoptotic platelets aggregate with monocytes during dengue infection and signal specific cytokine responses that may contribute to the pathogenesis of dengue.

Concepts: Immune system, Inflammation, Blood, Apoptosis, Platelet, Spleen, Thrombocytopenia, TGF beta 1

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Dysregulated inflammation is implicated in the pathobiology of aging, yet platelet-leukocyte interactions and downstream cytokine synthesis in aging remains poorly understood. Platelets and monocytes were isolated from healthy younger (age <45, n = 37) and older (age ≥65, n = 30) adults and incubated together under autologous and nonautologous conditions. Synthesis of inflammatory cytokines by monocytes, alone or in the presence of platelets, was examined. Next-generation RNA-sequencing allowed for unbiased profiling of the platelet transcriptome in aging. Basal IL-8 and MCP-1 synthesis by monocytes alone did not differ between older and younger adults. However, in the presence of autologous platelets, monocytes from older adults synthesized greater IL-8 (41 ± 5 versus 9 ± 2 ng/ml, p < 0.0001) and MCP-1 (867 ± 150 versus 216 ± 36 ng/ml, p < 0.0001) than younger adults. Platelets from older adults were sufficient for upregulating the synthesis of inflammatory cytokines by monocytes. Using RNA-sequencing of platelets followed by validation via RT-PCR and immunoblot, we discovered that granzyme A (GrmA), a serine protease not previously identified in human platelets, increases with aging (∼9-fold versus younger adults, p < 0.05) and governs increased IL-8 and MCP-1 synthesis through TLR4 and caspase-1. Inhibiting GrmA reduced excessive IL-8 and MCP-1 synthesis in aging to levels similar to younger adults. In summary, human aging is associated with changes in the platelet transcriptome and proteome. GrmA is present and bioactive in human platelets, is higher in older adults, and controls the synthesis of inflammatory cytokines by monocytes. Alterations in the platelet molecular signature and signaling to monocytes may contribute to dysregulated inflammatory syndromes in older adults.

Concepts: Inflammation, Cytokine, Atherosclerosis, Coagulation, Platelet, Ageing, Aging, TGF beta 1

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Camurati-Engelmann disease (CED) is a rare genetic skeletal disorder characterized by limb pain, muscle emaciation and weakness, and cortical thickening of the diaphysis of long bones. It is caused by mutations in the transforming growth factor beta 1 (TGFB1) (type I) or other unknown gene(s) (type II). We present 8 consecutive patients with type I CED.

Concepts: Immune system, Bone, Genetic disorder, Skeletal system, Type I and type II errors, TGF beta 1, Transforming growth factor, Diaphysis

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To evaluate the diagnostic and prognostic values of survivin and transforming growth factor beta-1 (TGF-B1) expression in aqueous humor and serum of retinoblastoma (RB) in comparison to the conventional RB marker lactate dehydrogenase (LDH) and to elucidate a possible correlation between them and the clinicopathological features of the disease.

Concepts: Cancer, Signal transduction, Medical terms, Hormone, Lactate dehydrogenase, Aqueous humour, TGF beta 1, Transforming growth factor

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Leucoreduction of blood components, including platelet components, is strongly encouraged but not yet universal, especially outside high income countries. As both leucocytes and platelets secrete copious amounts of pro-inflammatory cytokines/chemokines under various conditions and during storage, we investigated the potential of the respective secretory programmes of these cells in order to evaluate their subsequent pathophysiological effects.

Concepts: Blood, Bone marrow, Cell biology, Coagulation, Platelet, Spleen, TGF beta 1, Plateletpheresis

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Tumours constitute unique microenvironments where various blood cells and factors are exposed as a result of leaky vasculature. In the present study, we report that thrombin enrichment in B16F10 melanoma led to platelet aggregation, and this property was exploited to administer an anticancer cytokine, interferon-gamma induced protein 10 (IP10), through the formation of a platelet-IP10 complex. When intravenously infused, the complex reached platelet microaggregates in the tumour. The responses induced by the complex were solely immune-mediated, and tumour cytotoxicity was not observed. The complex suppressed the growth of mouse melanoma in vivo, while both platelets and the complex suppressed the accumulation of FoxP3(+) regulatory T cells in the tumour. These results demonstrated that thrombin-dependent platelet aggregation in B16F10 tumours defines platelets as a vector to deliver anticancer cytokines and provide specific treatment benefits.

Concepts: Gene, Oncology, Blood, Chemotherapy, Cytokines, Platelet, Interferon, TGF beta 1

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To elucidate whether platelets differentiate cytokine release following trauma, we prospectively measured three major platelet-derived cytokines in 213 trauma patients on hospital arrival.

Concepts: Hospital, Bone marrow, TGF beta 1, TGN1412

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Platelet-rich plasma (PRP) preparations are a common treatment in osteoarthritis (OA) and inflammatory synovitis. However, there is ambiguity regarding the ideal concentration of leukocytes and platelets in these preparations necessary to induce an adequate anti-inflammatory and anabolic response in joint tissues, such as the synovial membrane. This research aimed to study, in normal synovial membrane explants (SME) challenged with lipopolysaccharide (LPS), the temporal effects (at 48 and 96h) of leukocyte- and platelet-rich gel (L-PRG) and pure platelet-rich gel (P-PRG) supernatants on the production and degradation of platelet associated growth factors (GF) (platelet derived GF isoform BB (PDGF-BB) and transforming growth factor beta-1 (TGF-β1)), pro-inflammatory (tumour necrosis factor alpha (TNF-α)) and anti-inflammatory cytokines (interleukin 4 (IL-4) and IL-1 receptor antagonists (IL-1ra)) and hyaluronan (HA).

Concepts: Immune system, Inflammation, Cytokine, Signal transduction, Blood, Hormone, Apoptosis, TGF beta 1

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Intestinal epithelia regulate barrier integrity when challenged by inflammation, oxidative stress and microbes. Transforming growth factor (TGF)β1 is a cytokine with known beneficial effects on intestinal epithelia, including barrier enhancement, following exposure to pro-inflammatory cytokines and infectious agents. The aim of this study was to determine whether TGFβ1 directly protects intestinal epithelia during hypoxia-reoxygenation.

Concepts: Immune system, Cytokine, Signal transduction, Infection, Apoptosis, Interleukin, TGF beta 1

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Platelets in therapeutic platelet concentrates are commonly acknowledged to release biologically active constituents during storage. This study examined the influence of photochemical pathogen reduction treatment (PRT) using amotosalen-HCl and UVA light vs. untreated control platelet components, on three factors recently reported to be associated with serious adverse events associated with platelet component (PC) transfusions: sCD40L, IL-27 and sOX40 ligand. Levels of such cytokine-like factors increased significantly during storage, but no significant difference was detected between PRT- and control PCs. This suggests that occurrences of AEs are not directly influenced by PRT but rather may depend on alternate determinants.

Concepts: Blood, Chemotherapy, Platelet, TGF beta 1, Plateletpheresis, Clusters of differentiation