scholarly journals A sand fly salivary protein acts as a neutrophil chemoattractant

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anderson B. Guimaraes-Costa ◽  
John P. Shannon ◽  
Ingrid Waclawiak ◽  
Jullyanna Oliveira ◽  
Claudio Meneses ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Calcium Influx ◽  
Parasite Burden ◽  
Salivary Protein ◽  
Sand Fly ◽  
Human Neutrophils ◽  
Chemotactic Protein ◽  
The Impact

AbstractApart from bacterial formyl peptides or viral chemokine mimicry, a non-vertebrate or insect protein that directly attracts mammalian innate cells such as neutrophils has not been molecularly characterized. Here, we show that members of sand fly yellow salivary proteins induce in vitro chemotaxis of mouse, canine and human neutrophils in transwell migration or EZ-TAXIScan assays. We demonstrate murine neutrophil recruitment in vivo using flow cytometry and two-photon intravital microscopy in Lysozyme-M-eGFP transgenic mice. We establish that the structure of this ~ 45 kDa neutrophil chemotactic protein does not resemble that of known chemokines. This chemoattractant acts through a G-protein-coupled receptor and is dependent on calcium influx. Of significance, this chemoattractant protein enhances lesion pathology (P < 0.0001) and increases parasite burden (P < 0.001) in mice upon co-injection with Leishmania parasites, underlining the impact of the sand fly salivary yellow proteins on disease outcome. These findings show that some arthropod vector-derived factors, such as this chemotactic salivary protein, activate rather than inhibit the host innate immune response, and that pathogens take advantage of these inflammatory responses to establish in the host.

scholarly journals Targeting redox regulatory site of protein kinase B impedes neutrophilic inflammation in lung injury

2018 ◽  
Author(s):  
Po-Jen Chen ◽  
I-Ling Ko ◽  
Chia-Lin Lee ◽  
Hao-Chun Hu ◽  
Fang-Rong Chang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Lung Injury ◽  
Inflammatory Responses ◽  
Protein Kinase B ◽  
Reduced Form ◽  
Human Neutrophils ◽  
Akt Inhibitor ◽  
Neutrophilic Inflammation

AbstractNeutrophil activation has a pathogenic effect in inflammatory diseases. Protein kinase B (PKB)/AKT regulates diverse cellular responses. However, the significance of AKT in neutrophilic inflammation is still not well understood. Here, we identified CLLV-1 as a novel AKT inhibitor. CLLV-1 inhibited respiratory burst, degranulation, chemotaxis, and AKT phosphorylation in activated human neutrophils and dHL-60 cells. Significantly, CLLV-1 blocked AKT activity and covalently reacted with AKT Cys310 in vitro. The AKT309-313 peptide-CLLV-1 adducts were determined by NMR or mass spectrometry assay. The alkylation agent-conjugated AKT (reduced form) level was also inhibited by CLLV-1. Additionally, CLLV-1 ameliorated lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. CLLV-1 acts as a covalent allosteric AKT inhibitor by targeting AKT Cys310 to restrain inflammatory responses in human neutrophils and LPS-induced ALI in vivo. Our findings provide a mechanistic framework for redox modification of AKT that may serve as a novel pharmacological target to alleviate neutrophilic inflammation.

scholarly journals Modulation of inflammatory responses by Sutherlandia frutescens

2015 ◽  
Author(s):  
◽  
Wei Lei
Keyword(s):  
Aqueous Extract ◽  
Inflammatory Responses ◽  
Ethanolic Extract ◽  
Microbial Activities ◽  
Murine Macrophages ◽  
Oral Consumption ◽  
Anti Inflammatory ◽  
The Impact

Sutherlandia frutescens (L.) R. Br (Lessertia frutescens) is a medicinal plant traditionally used in southern Africa. It has been used for patients suffering from numerous types of cancer, infectious diseases, and various inflammatory conditions. This study was designed to determine the impact of S. frutescens on the inflammatory response and anti-microbial activities on cell and/or animal models. Aqueous and ethanolic extracts of S. frutescens were made and verified using HPLC. These extracts were used to treat murine macrophages (e.g., RAW 264.7 cells and primary macrophages isolated from mice) to evaluate the impact of S. frutescens on in vitro inflammatory responses. This study found that the aqueous extract and a polysaccharide-enriched fraction from the aqueous extract exhibited an immuno-stimulatory activity on murine macrophages. Treatment with aqueous extract or polysaccharides increased the production of reactive oxygen species (ROS), nitric oxide (NO), and inflammatory cytokines/chemokines via activating the toll-like receptor 4 signaling pathway. On the other hand, the ethanolic extract of S. frutescens dose-dependently decreased the production of ROS, NO, inducible nitric oxide synthase (iNOS), and various inflammatory cytokines and chemokines in murine macrophages co-stimulated with lipopolysaccharide (LPS) and interferon gamma (IFNy). Follow up experiments demonstrated that the anti-inflammatory activity of the ethanolic extract was mediated via reductions in the activation of NF-kB, extracellular-signal-regulated kinase 1/2 (ERK1/2), and signal transducers and activators of transcription 1 (STAT1). RNA sequencing provided more evidences to support the anti-inflammatory activity of the ethanolic extract of S. frutescens. To our surprise, chlorophylls isolated from S. frutescens had a greater effect on the anti-inflammatory of S. frutescens than that of unique compounds (i.e., sutherlandiosides and sutherlandins). To investigate the impact of oral consumption of S. frutescens on in vivo inflammatory responses and anti-microbial activities, mice were fed with AIN-93G based diet with/without containing ground S. frutescens powder or were gavaged with S. frutescens extracts followed by challenge with E. coli or LPS. These experiments found that oral consumption of S. frutescens had limited or no impact on the in vivo inflammatory responses and anti-microbial activities. Overall, this study provide a better understanding on the beneficial therapeutic properties of S. frutescens using in vitro models, however these studies in a laboratory mouse model suggest that consumption of S. frutescens had only a modest impact on host anti-microbial and inflammatory responses to a gram-negative microbial challenge whether intact microbes or bacterial endotoxin (i.e., LPS) was used.

scholarly journals Klotho Alleviates Lung Injury Caused by Paraquat via Suppressing ROS/P38 MAPK-Regulated Inflammatory Responses and Apoptosis

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhiqiang Zhang ◽  
Qing Nian ◽  
Gang Chen ◽  
Shuqing Cui ◽  
Yuzhen Han ◽  
...  
Keyword(s):  
Lung Injury ◽  
Cell Viability ◽  
P38 Mapk ◽  
Inflammatory Responses ◽  
A549 Cells ◽  
Control Group ◽  
Ros Production ◽  
The Impact

Acute lung injury (ALI) induced by paraquat (PQ) progresses rapidly with high mortality; however, there is no effective treatment, and the specific mechanism is not well understood. The antiaging protein klotho (KL) has multiple functions and exerts significant influences on various pathophysiological processes. This work evaluated the impact of KL on PQ-induced ALI and investigated its underlying mechanisms. As for in vivo research, C57BL/6 mice were treated with PQ (30 mg/kg) intraperitoneal (IP) injection to create a toxicity model of ALI (PQ group). The mice were divided into control group, KL group, PQ group, and PQ+KL group. For in vitro experiment, A549 cells were incubated with or without KL and then treated in the presence or absence of PQ for 24 h. In vivo result indicated that KL reduced the mortality, reduced IL-1β and IL-6 in the bronchoalveolar lavage fluid (BALF), attenuated ALI, and decreased apoptosis in situ. In vitro result revealed that KL significantly improved cell viability, reduced the levels of IL-1β and IL-6 in culture supernatants, suppressed cell apoptosis, inhibited caspase-3 activation, and enhanced mitochondrial membrane potential (ΔΨm) after PQ treatment. Besides, KL effectively abated reactive oxygen species (ROS) production, improved GSH content, and lowered lipid peroxidation in PQ-exposed A549 cells. Further experiments indicated that phosphorylated JNK and P38 MAPK was increased after PQ treatment; however, KL pretreatment could significantly lower the phosphorylation of P38 MAPK. Suppression of P38 MAPK improved cell viability, alleviated inflammatory response, and reduced apoptosis-related signals; however, it had no obvious effect on the production of ROS. Treatment with N-acetylcysteine (NAC), a classic ROS scavenger, could suppress ROS production and P38 MAPK activation. These findings suggested that KL could alleviate PQ-caused ALI via inhibiting ROS/P38 MAPK signaling-regulated inflammatory responses and mitochondria-dependent apoptosis.

scholarly journals The Impact of Acute or Chronic Alcohol Intake on the NF-κB Signaling Pathway in Alcohol-Related Liver Disease

2020 ◽  
Vol 21 (24) ◽  
pp. 9407
Author(s):  
Aleksander J. Nowak ◽  
Borna Relja
Keyword(s):  
Liver Disease ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Inflammatory Responses ◽  
Current Knowledge ◽  
In Vivo Studies ◽  
Related Liver Disease ◽  
The Impact

Ethanol misuse is frequently associated with a multitude of profound medical conditions, contributing to health-, individual- and social-related damage. A particularly dangerous threat from this classification is coined as alcoholic liver disease (ALD), a liver condition caused by prolonged alcohol overconsumption, involving several pathological stages induced by alcohol metabolic byproducts and sustained cellular intoxication. Molecular, pathological mechanisms of ALD principally root in the innate immunity system and are especially associated with enhanced functionality of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. NF-κB is an interesting and convoluted DNA transcription regulator, promoting both anti-inflammatory and pro-inflammatory gene expression. Thus, the abundancy of studies in recent years underlines the importance of NF-κB in inflammatory responses and the mechanistic stimulation of inner molecular motifs within the factor components. Hereby, in the following review, we would like to put emphasis on the correlation between the NF-κB inflammation signaling pathway and ALD progression. We will provide the reader with the current knowledge regarding the chronic and acute alcohol consumption patterns, the molecular mechanisms of ALD development, the involvement of the NF-κB pathway and its enzymatic regulators. Therefore, we review various experimental in vitro and in vivo studies regarding the research on ALD, including the recent active compound treatments and the genetic modification approach. Furthermore, our investigation covers a few human studies.

scholarly journals Role of RAGE and Its Ligands on Inflammatory Responses to Brain Tumors

2021 ◽  
Vol 15 ◽  
Author(s):  
Griffith Kyle Otazu ◽  
Mojtaba Dayyani ◽  
Behnam Badie
Keyword(s):  
Cancer Progression ◽  
Inflammatory Responses ◽  
Checkpoint Inhibitors ◽  
Malignant Gliomas ◽  
Low Grade ◽  
Molecular Pattern ◽  
The Impact

Gliomas, the most common form of brain cancer, can range from relatively slow-growing low-grade to highly aggressive glioblastoma that has a median overall survival of only 15 months despite multimodal standard therapy. Although immunotherapy with checkpoint inhibitors has significantly improved patient survival for some cancers, to date, these agents have not shown consistent efficacy against malignant gliomas. Therefore, there is a pressing need to better understand the impact of host inflammatory responses on the efficacy of emerging immunotherapy approaches for these resistant tumors. RAGE is a multi-ligand pattern recognition receptor that is activated in various inflammatory states such as diabetes, Alzheimer’s disease, cystic fibrosis, and cancer. Low levels of RAGE can be found under normal physiological conditions in neurons, immune cells, activated endothelial, and vascular smooth muscle cells, but it is over-expressed under chronic inflammation due to the accumulation of its ligands. RAGE binds to a range of damage-associated molecular pattern molecules (DAMPs) including AGEs, HMGB1, S100s, and DNA which mediate downstream cellular responses that promote tumor growth, angiogenesis, and invasion. Both in vitro and in vivo studies have shown that inhibition of RAGE signaling can disrupt inflammation and cancer progression and metastasis. Here, we will review our current understanding of the role of RAGE pathway on glioma progression and how it could be exploited to improve the efficacy of immunotherapy approaches.

scholarly journals Generation and Characterization of B7-H4/B7S1/B7x-Deficient Mice

2006 ◽  
Vol 26 (17) ◽  
pp. 6403-6411 ◽  
Author(s):  
Woong-Kyung Suh ◽  
Seng Wang ◽  
Gordon S. Duncan ◽  
Yoshiyuki Miyazaki ◽  
Elizabeth Cates ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Leishmania Major ◽  
Inflammatory Responses ◽  
Fine Tuning ◽  
Th2 Cells ◽  
The Impact ◽  
Deficient Mice

ABSTRACT Members of the B7 family of cosignaling molecules regulate T-cell proliferation and effector functions by engaging cognate receptors on T cells. In vitro and in vivo blockade experiments indicated that B7-H4 (also known as B7S1 or B7x) inhibits proliferation, cytokine production, and cytotoxicity of T cells. B7-H4 binds to an unknown receptor(s) that is expressed on activated T cells. However, whether B7-H4 plays nonredundant immune regulatory roles in vivo has not been tested. We generated B7-H4-deficient mice to investigate the roles of B7-H4 during various immune reactions. Consistent with its inhibitory function in vitro, B7-H4-deficient mice mounted mildly augmented T-helper 1 (Th1) responses and displayed slightly lowered parasite burdens upon Leishmania major infection compared to the wild-type mice. However, the lack of B7-H4 did not affect hypersensitive inflammatory responses in the airway or skin that are induced by either Th1 or Th2 cells. Likewise, B7-H4-deficient mice developed normal cytotoxic T-lymphocyte reactions against viral infection. Thus, B7-H4 plays a negative regulatory role in vivo but the impact of B7-H4 deficiency is minimal. These results suggest that B7-H4 is one of multiple negative cosignaling molecules that collectively provide a fine-tuning mechanism for T-cell-mediated immune responses.

scholarly journals The histamine H4 receptor mediates inflammation and Th17 responses in preclinical models of arthritis

2013 ◽  
Vol 73 (3) ◽  
pp. 600-608 ◽  
Author(s):  
Jeffery M Cowden ◽  
Fuqu Yu ◽  
Homayon Banie ◽  
Mandana Farahani ◽  
Ping Ling ◽  
...  
Keyword(s):  
Th17 Cells ◽  
Inflammatory Responses ◽  
Total Production ◽  
Histamine H4 Receptor ◽  
Model Treatment ◽  
H4 Receptor ◽  
The Impact ◽  
Deficient Mice

ObjectiveThe histamine H4 receptor (H4R) has been shown to drive inflammatory responses in models of asthma, colitis and dermatitis, and in these models it appears to affect both innate and adaptive immune responses. In this study, we used both H4R-deficient mice and a specific H4R antagonist, JNJ 28307474, to investigate the involvement of the H4R in mouse arthritis models.MethodsH4R-deficient mice and wild-type mice administered the H4R antagonist were studied in models of collagen antibody-induced arthritis (CAIA) and collagen-induced arthritis (CIA). The impact on Th17 cells was assessed by restimulation of inguinal lymphocytes in the disease or immunisation models and with in vitro stimulation of whole blood.ResultsBoth H4R-deficient mice and mice treated with the H4R antagonist exhibited reduced arthritis disease severity in both CAIA and CIA models. This was evident from the reduction in disease score and in joint histology. In the CIA model, treatment with the H4R antagonist reduced the number of interleukin (IL)-17 positive cells in the lymph node and the total production of IL-17. Th17 cell development in vivo was reduced in H4R-deficient mice or in mice treated with an H4R antagonist. Finally, treatment of both mouse and human blood with an H4R antagonist reduced the production of IL-17 when cells were stimulated in vitro.ConclusionsThese results implicate the H4R in disease progression in arthritis and in the production of IL-17 from Th17 cells. This work supports future clinical exploration of H4R antagonists for the treatment of rheumatoid arthritis.

scholarly journals Gain-of-Function Mutation of Tristetraprolin Impairs Negative Feedback Control of Macrophages In Vitro yet Has Overwhelmingly Anti-Inflammatory Consequences In Vivo

2017 ◽  
Vol 37 (11) ◽  
Author(s):  
John D. O'Neil ◽  
Ewan A. Ross ◽  
Michael L. Ridley ◽  
Qize Ding ◽  
Tina Tang ◽  
...  
Keyword(s):  
Feedback Control ◽  
Negative Feedback ◽  
Inflammatory Responses ◽  
Interleukin 10 ◽  
Gain Of Function ◽  
Negative Feedback Control ◽  
Anti Inflammatory ◽  
The Impact

ABSTRACT The mRNA-destabilizing factor tristetraprolin (TTP) binds in a sequence-specific manner to the 3′ untranslated regions of many proinflammatory mRNAs and recruits complexes of nucleases to promote rapid mRNA turnover. Mice lacking TTP develop a severe, spontaneous inflammatory syndrome characterized by the overexpression of tumor necrosis factor and other inflammatory mediators. However, TTP also employs the same mechanism to inhibit the expression of the potent anti-inflammatory cytokine interleukin 10 (IL-10). Perturbation of TTP function may therefore have mixed effects on inflammatory responses, either increasing or decreasing the expression of proinflammatory factors via direct or indirect mechanisms. We recently described a knock-in mouse strain in which the substitution of 2 amino acids of the endogenous TTP protein renders it constitutively active as an mRNA-destabilizing factor. Here we investigate the impact on the IL-10-mediated anti-inflammatory response. It is shown that the gain-of-function mutation of TTP impairs IL-10-mediated negative feedback control of macrophage function in vitro. However, the in vivo effects of TTP mutation are uniformly anti-inflammatory despite the decreased expression of IL-10.

An ACE inhibitor reduces bactericidal activity of human neutrophils in vitro and impairs mouse neutrophil activity in vivo

2021 ◽  
Vol 13 (604) ◽  
pp. eabj2138
Author(s):  
Duo-Yao Cao ◽  
Jorge F. Giani ◽  
Luciana C. Veiras ◽  
Ellen A. Bernstein ◽  
Derick Okwan-Duodu ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Angiotensin Converting Enzyme Inhibitors ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
Converting Enzyme Inhibitors ◽  
Bacterial Killing ◽  
Increased Risk ◽  
The Impact

Angiotensin-converting enzyme inhibitors (ACEIs) are used by millions of patients to treat hypertension, diabetic kidney disease, and heart failure. However, these patients are often at increased risk of infection. To evaluate the impact of ACEIs on immune responses to infection, we compared the effect of an ACEI versus an angiotensin receptor blocker (ARB) on neutrophil antibacterial activity. ACEI exposure reduced the ability of murine neutrophils to kill methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae in vitro. In vivo, ACEI-treated mice infected with MRSA had increased bacteremia and tissue bacteria counts compared to mice treated with an ARB or with no drug. Similarly, ACEIs, but not ARBs, increased the incidence of MRSA-induced infective endocarditis in mice with aortic valve injury. Neutrophils from ACE knockout (KO) mice or mice treated with an ACEI produced less leukotriene B4 (LTB4) upon stimulation with MRSA or lipopolysaccharide, whereas neutrophils overexpressing ACE produced more LTB4 compared to wild-type neutrophils. As a result of reduced LTB4 production, ACE KO neutrophils showed decreased survival signaling and increased apoptosis. In contrast, neutrophils overexpressing ACE had an enhanced survival phenotype. Last, in a cohort of human volunteers receiving the ACEI ramipril for 1 week, ACEI administration reduced neutrophil superoxide and reactive oxygen species production and neutrophils isolated from volunteers during ramipril treatment had reduced bactericidal activity. Together, these data demonstrate that ACEI treatment, but not ARB treatment, can reduce the bacterial killing ability of neutrophils.

scholarly journals PI3Kδ Sustains Keratinocyte Hyperproliferation and Epithelial Inflammation: Implications for a Topically Druggable Target in Psoriasis

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2636
Author(s):  
Laura Mercurio ◽  
Martina Morelli ◽  
Claudia Scarponi ◽  
Giovanni Luca Scaglione ◽  
Sabatino Pallotta ◽  
...  
Keyword(s):  
Skin Diseases ◽  
Inflammatory Responses ◽  
Basal Layer ◽  
Regulatory Subunit ◽  
Psoriatic Skin ◽  
Epidermal Keratinocytes ◽  
Epithelial Inflammation ◽  
The Impact

The phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathway is aberrantly activated in psoriatic lesions and contributes to disease pathogenesis. Among PI3Ks enzymes, PI3Kα, β, and δ isoforms are known to bind the p85 regulatory subunit and mediate activation of AKT and other downstream effectors. In this study, we deepened our understanding of the expression and function of PI3Kδ in skin lesions of patients affected by psoriasis. For the first time, we found that PI3Kδ is overexpressed in psoriatic plaques, and its expression is not only confined to infiltrating immune cells but also accumulates in proliferating keratinocytes of the epidermal basal layer. We investigated the function of PI3Kδ in psoriatic skin by evaluating the impact of seletalisib, a newly developed selective PI3Kδ inhibitor, in both in vitro and in vivo experimental models of psoriasis. Of note, we found that PI3Kδ sustains keratinocyte hyperproliferation and impaired terminal differentiation induced by IL-22, as well as induces epithelial inflammation and resistance to apoptosis mediated by TNF-α in human keratinocytes. Mechanistically, PI3Kδ promotes PDK1 phosphorylation and signals through AKT-dependent or -independent pathways. It is worth mentioning that PI3Kδ inhibition by seletalisib attenuates the severity of psoriasiform phenotype induced in the Imiquimod-induced mouse model of psoriasis by restoring the physiological proliferation and differentiation programs in epidermal keratinocytes and contrasting the cutaneous inflammatory responses. Therefore, we suggest PI3Kδ as a potential topically druggable target in psoriasis and skin diseases characterized by epidermal hyperproliferation and skin inflammation.

Sign in / Sign up

Export Citation Format

Share Document