scholarly journals Serum Amyloid A Proteins Induce Pathogenic TH17 Cells and Promote Inflammatory Disease

2019 ◽  
Author(s):  
June-Yong Lee ◽  
Jason A. Hall ◽  
Lina Kroehling ◽  
Lin Wu ◽  
Tariq Najar ◽  
...  
Keyword(s):  
T Cells ◽  
Serum Amyloid A ◽  
Inflammatory Diseases ◽  
Lymphoid Cells ◽  
Serum Amyloid ◽  
Intestinal Epithelial ◽  
T Cell Signaling ◽  
Cell Behaviors ◽  
Amyloid A ◽  
Barrier Tissues

SummaryLymphoid cells that produce IL-17 cytokines protect barrier tissues from pathogenic microbes, but are also prominent effectors of inflammation and autoimmune disease. T-helper (TH17) cells, defined by RORγt-dependent production of IL-17A and IL-17F, exert homeostatic functions in the gut upon microbiota-directed differentiation from naïve CD4+ T cells. In the non-pathogenic setting, their cytokine production is regulated by serum amyloid A proteins (SAA1 and SAA2) secreted by adjacent intestinal epithelial cells. However, TH17 cell behaviors vary markedly according to their environment. Here we show that SAAs additionally direct a pathogenic pro-inflammatory TH17 cell differentiation program, acting directly on T cells in collaboration with STAT3-activating cytokines. Using loss- and gain-of-function mouse models, we show that SAA1, SAA2, and SAA3 have distinct systemic and local functions in promoting TH17-mediated inflammatory diseases. These studies suggest that T cell signaling pathways modulated by the SAAs may be attractive targets for anti-inflammatory therapies.

scholarly journals Role of Serum Amyloid A Protein in Various Diseases with Special Reference to Periodontal and Periapical Inflammation- A Review

2020 ◽  
Author(s):  
Syed Wali Peeran ◽  
Ahmed Elhassan ◽  
Mohammed Zameer ◽  
Syed Nahid Basheer ◽  
Mohammed Mustafa ◽  
...  
Keyword(s):  
Chronic Periodontitis ◽  
Serum Amyloid A ◽  
Inflammatory Diseases ◽  
Apical Periodontitis ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Serum Amyloid A Protein ◽  
Health And Disease ◽  
Periapical Inflammation

Serum Amyloid A (SAA) is an Acute-Phase Protein (APP) produced as an innate nonspecific response to any tissue damage. Hence, it plays a significant role in chronic inflammatory diseases. In particular, SAA levels increase dramatically in chronic periodontitis and chronic apical periodontitis. Recent studies suggest this role of SAA in the pathogenesis of various diseases, including chronic periodontitis and chronic apical periodontitis. Thus, the focus of this review is to sum up the current understanding of the role of SAA in health and disease and to elaborate on possible mechanisms by which SAA could play a role in the pathogenesis of chronic periodontitis and chronic apical periodontitis.

scholarly journals Serum amyloid A induces G-CSF expression and neutrophilia via Toll-like receptor 2

Blood ◽  
2009 ◽  
Vol 113 (2) ◽  
pp. 429-437 ◽  
Author(s):  
Rong L. He ◽  
Jian Zhou ◽  
Crystal Z. Hanson ◽  
Jia Chen ◽  
Ni Cheng ◽  
...  
Keyword(s):  
Serum Amyloid A ◽  
Inflammatory Diseases ◽  
Serum Amyloid ◽  
Proteinase K ◽  
In Vivo Studies ◽  
Toll Like Receptor ◽  
Amyloid A ◽  
Toll Like Receptor 2

Abstract The acute-phase protein serum amyloid A (SAA) is commonly considered a marker for inflammatory diseases; however, its precise role in inflammation and infection, which often result in neutrophilia, remains ambiguous. In this study, we demonstrate that SAA is a potent endogenous stimulator of granulocyte colony-stimulated factor (G-CSF), a principal cytokine-regulating granulocytosis. This effect of SAA is dependent on Toll-like receptor 2 (TLR2). Our data demonstrate that, in mouse macrophages, both G-CSF mRNA and protein were significantly increased after SAA stimulation. The induction of G-CSF was blocked by an anti-TLR2 antibody and markedly decreased in the TLR2-deficient macrophages. SAA stimulation results in the activation of nuclear factor–κB and binding activity to the CK-1 element of the G-CSF promoter region. In vitro reconstitution experiments also support that TLR2 mediates SAA-induced G-CSF expression. In addition, SAA-induced secretion of G-CSF was sensitive to heat and proteinase K treatment, yet insensitive to polymyxin B treatment, indicating that the induction is a direct effect of SAA. Finally, our in vivo studies confirmed that SAA treatment results in a significant increase in plasma G-CSF and neutrophilia, whereas these responses are ablated in G-CSF– or TLR2-deficient mice.

scholarly journals Serum Amyloid A Promotes Lung Neutrophilia by Increasing IL-17A Levels in the Mucosa and γδ T Cells

2013 ◽  
Vol 188 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Desiree Anthony ◽  
Huei Jiunn Seow ◽  
Mohib Uddin ◽  
Michelle Thompson ◽  
Lovisa Dousha ◽  
...  
Keyword(s):  
T Cells ◽  
Serum Amyloid A ◽  
Γδ T Cells ◽  
Serum Amyloid ◽  
Amyloid A

scholarly journals Elevated Serum Amyloid a Levels Are not Specific for Sarcoidosis but Associate with a Fibrotic Pulmonary Phenotype

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 585
Author(s):  
Els Beijer ◽  
Claudia Roodenburg-Benschop ◽  
Milou C. Schimmelpennink ◽  
Jan C. Grutters ◽  
Bob Meek ◽  
...  
Keyword(s):  
Serum Amyloid A ◽  
Inflammatory Diseases ◽  
Elevated Serum ◽  
Serum Levels ◽  
Serum Amyloid ◽  
Eosinophilic Granulomatosis With Polyangiitis ◽  
Amyloid A ◽  
Underlying Mechanisms ◽  
Granulomatous Diseases

Elevated Serum Amyloid A (SAA) levels have been found in several inflammatory diseases, including sarcoidosis. SAA is suggested to be involved in sarcoidosis pathogenesis by involvement in granuloma formation and maintenance. We hypothesized that SAA serum levels would be higher in sarcoidosis compared to other non-infectious granulomatous and non-granulomatous diseases. SAA levels were measured in serum from sarcoidosis, Hypersensitivity pneumonitis (HP), and (eosinophilic) granulomatosis with polyangiitis ((E)GPA) patients. Idiopathic pulmonary fibrosis (IPF) patients were included as non-granulomatous disease group. SAA levels of patients with sarcoidosis (31.0 µg/mL), HP (23.4 µg/mL), (E)GPA (36.9 µg/mL), and IPF (22.1 µg/mL) were all higher than SAA levels of healthy controls (10.1 µg/mL). SAA levels did not differ between the diagnostic groups. When SAA serum levels were analyzed in sarcoidosis subgroups, fibrotic sarcoidosis patients showed higher SAA levels than sarcoidosis patients without fibrosis (47.8 µg/mL vs. 29.4 µg/mL, p = 0.005). To conclude, the observation that fibrotic sarcoidosis patients have higher SAA levels, together with our finding that SAA levels were also increased in IPF patients, suggests that SAA may next to granulomatous processes also reflect the process of fibrogenesis. Further studies should clarify the exact role of SAA in fibrosis and the underlying mechanisms involved.

scholarly journals High-Density Lipoproteins and Serum Amyloid A (SAA)

2021 ◽  
Vol 23 (2) ◽  
Author(s):  
Nancy R. Webb
Keyword(s):  
Serum Amyloid A ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Density Lipoprotein ◽  
High Density ◽  
Serum Amyloid ◽  
High Density Lipoproteins ◽  
Amyloid A

Abstract Purpose of Review Serum amyloid A (SAA) is a highly sensitive acute phase reactant that has been linked to a number of chronic inflammatory diseases. During a systemic inflammatory response, liver-derived SAA is primarily found on high-density lipoprotein (HDL). The purpose of this review is to discuss recent literature addressing the pathophysiological functions of SAA and the significance of its association with HDL. Recent Findings Studies in gene-targeted mice establish that SAA contributes to atherosclerosis and some metastatic cancers. Accumulating evidence indicates that the lipidation state of SAA profoundly affects its bioactivities, with lipid-poor, but not HDL-associated, SAA capable of inducing inflammatory responses in vitro and in vivo. Factors that modulate the equilibrium between lipid-free and HDL-associated SAA have been identified. Summary HDL may serve to limit SAA’s bioactivities in vivo. Understanding the factors leading to the release of systemic SAA from HDL may provide insights into chronic disease mechanisms.

scholarly journals Serum amyloid A induces mitogenic signals in regulatory T cells via monocyte activation

2014 ◽  
Vol 59 (2) ◽  
pp. 172-179 ◽  
Author(s):  
Khoa D. Nguyen ◽  
Claudia Macaubas ◽  
Phi Truong ◽  
Nan Wang ◽  
Tieying Hou ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Serum Amyloid A ◽  
Serum Amyloid ◽  
Monocyte Activation ◽  
Amyloid A ◽  
Mitogenic Signals

scholarly journals Analytical Validation of Two Point-of-Care Assays for Serum Amyloid A Measurements in Cats

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2518
Author(s):  
Damián Escribano ◽  
Alba Ortín Bustillo ◽  
Luis Pardo Marín ◽  
Andrea Navarro Rabasco ◽  
Pablo Ruiz Herrera ◽  
...  
Keyword(s):  
Gold Standard ◽  
Serum Amyloid A ◽  
Performance Test ◽  
Limit Of Detection ◽  
Inflammatory Diseases ◽  
Point Of Care ◽  
Serum Amyloid ◽  
Analytical Validation ◽  
Serum Samples ◽  
Amyloid A

Serum Amyloid A (SAA) is one of the most sensitive tests to detect inflammation in cats. In this study, two point-of-care assays for SAA measurements in cats (FUJI DRI-CHEM IMMUNO AU CARTRIDGE vf-SAA (method A), and CUBE-VET analyser (Method B), were analytically evaluated. Regarding the imprecision precision only the method A showed intra-assay and inter-assay CV < 10% at all concentrations. Both assays showed linearity with r close to 1 and the recovery were in the range of 81–112% for assay A and 85–125% for assay B and the limit of detection were 3.75 and 0.5 mg/dL for method A and B, respectively. A previously validated method for SAA quantification SAATIA; LZ-SAA (method C) was used as gold-standard to evaluate the accuracy of the assays. Significant correlations (p < 0.0001) were found between assays A and C (r = 0.94) and B and C (r = 0.91). In addition, an overlap performance test was made using serum samples from cats with non-inflammatory and cats with inflammatory. Both assays showed higher median SAA concentrations in cats with inflammatory diseases than in cats without inflammatory diseases (p < 0.0001). In conclusion, this manuscript provides data about the possible application of two point-of-care assays for the measurement of SAA concentration in cats.

scholarly journals Influence of Serum Amyloid A Protein on HDL Metabolism in Inflammatory Diseases

1992 ◽  
Vol 20 (2-3) ◽  
pp. 101-109 ◽  
Author(s):  
Yukio IKEDA ◽  
Yoshitaka KUMON ◽  
Kenzo YOSHIDA ◽  
Tadashi SUEHIRO ◽  
Fumitoshi OHNO
Keyword(s):  
Serum Amyloid A ◽  
Inflammatory Diseases ◽  
Serum Amyloid ◽  
Amyloid A ◽  
Serum Amyloid A Protein ◽  
Hdl Metabolism
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