CXCL12 ameliorates neutrophilia and disease severity in SARS-CoV-2 infection.

Neutrophils, particularly low-density neutrophils (LDNs), are believed to contribute to acute COVID-19 severity. Here, we showed that neutrophilia can be detected acutely and even months after SARS-CoV-2 infection in patients and mice, while neutrophil depletion reduced disease severity in mice. A key factor in neutrophilia and severe disease in infected mice was traced to the chemokine CXCL12 secreted by bone marrow cells and unexpectedly, endothelial cells.

The prostaglandin D2 antagonist asapiprant ameliorates clinical severity in young hosts infected with invasive .

(pneumococcus) remains a serious cause of pulmonary and systemic infections globally, and host-directed therapies are lacking. The aim of this study was to test the therapeutic efficacy of asapiprant, an inhibitor of prostaglandin D2 signaling, against pneumococcal infection. Treatment of young mice with asapiprant after pulmonary infection with invasive pneumococci significantly reduced systemic spread, disease severity, and host death.

The discovery of novel and potent indazole NLRP3 inhibitors enabled by DNA-encoded library screening.

NLRP3 is an intracellular sensor protein that detects a broad range of danger signals and environmental insults. Its activation results in a protective pro-inflammatory response designed to impair pathogens and repair tissue damage via the formation of the NLRP3 inflammasome. Assembly of the NLRP3 inflammasome leads to caspase 1-dependent secretory release of the pro-inflammatory cytokines IL-1β and IL-18 as well as to gasdermin d-mediated pyroptotic cell death.

N-Oleoyl dopamine induces IL-10 via central nervous system TRPV1 and improves endotoxemia and sepsis outcomes.

Background: The transient receptor potential vanilloid 1 (TRPV1) participates in thermosensation and inflammatory pain, but its immunomodulatory mechanisms remain enigmatic. N-Oleoyl dopamine (OLDA), an endovanilloid and endocannabinoid, is a TRPV1 agonist that is produced in the central nervous system and the peripheral nervous system. We studied the anti-inflammatory effects and TRPV1-dependent mechanisms of OLDA in models of inflammation and sepsis.

Eicosanoid signalling blockade protects middle-aged mice from severe COVID-19.

Coronavirus disease 2019 (COVID-19) is especially severe in aged populations. Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are highly effective, but vaccine efficacy is partly compromised by the emergence of SARS-CoV-2 variants with enhanced transmissibility. The emergence of these variants emphasizes the need for further development of anti-SARS-CoV-2 therapies, especially for aged populations.

Eicosanoid signaling as a therapeutic target in middle-aged mice with severe COVID-19.

Coronavirus disease 2019 (COVID-19) is especially severe in aged populations. Resolution of the COVID-19 pandemic has been advanced by the recent development of SARS-CoV-2 vaccines, but vaccine efficacy is partly compromised by the recent emergence of SARS-CoV-2 variants with enhanced transmissibility. The emergence of these variants emphasizes the need for further development of anti-SARS-CoV-2 therapies, especially in aged populations.

EGFR-dependent tyrosine phosphorylation of integrin β4 is not required for downstream signaling events in cancer cell lines.

In epithelial cancers, the epidermal growth factor receptor (EGFR) and integrin α6β4 are frequently overexpressed and found to synergistically activate intracellular signaling pathways that promote cell proliferation and migration. In cancer cells, the β4 subunit is phosphorylated at tyrosine residues not normally recognized as kinase substrates; however, the function of these phosphotyrosine residues in cancer cells is a subject of much debate. In EGFR-overexpressing carcinoma cells, we found that the Src family kinase (SFK) inhibitor PP2 reduces β4 tyrosine phosphorylation following the activation of EGFR.

ERK1/2 Has Divergent Roles in LPS-Induced Microvascular Endothelial Cell Cytokine Production and Permeability.

Endothelial cells play a major role in inflammatory responses to infection and sterile injury. Endothelial cells express Toll-like receptor 4 (TLR4) and are activated by LPS to express inflammatory cytokines/chemokines, and to undergo functional changes, including increased permeability. The extracellular signal-regulated kinase 1/2 (ERK1/2) mediates pro-inflammatory signaling in monocytes and macrophages, but the role of ERK1/2 in LPS-induced activation of microvascular endothelial cells has not been defined.

-Arachidonoyl Dopamine Modulates Acute Systemic Inflammation via Nonhematopoietic TRPV1.

-Arachidonoyl dopamine (NADA) is an endogenous lipid that potently activates the transient receptor potential vanilloid 1 (TRPV1), which mediates pain and thermosensation. NADA is also an agonist of cannabinoid receptors 1 and 2. We have reported that NADA reduces the activation of cultured human endothelial cells by LPS and TNF-α.

Vascular endothelial cell Toll-like receptor pathways in sepsis.

The endothelium forms a vast network that dynamically regulates vascular barrier function, coagulation pathways and vasomotor tone. Microvascular endothelial cells are uniquely situated to play key roles during infection and injury, owing to their widespread distribution throughout the body and their constant interaction with circulating blood. While not viewed as classical immune cells, endothelial cells express innate immune receptors, including the Toll-like receptors (TLRs), which activate intracellular inflammatory pathways mediated through NF-κB and the MAP kinases.

Extracellular signal-regulated kinase 5 promotes acute cellular and systemic inflammation.

Inflammatory critical illness is a syndrome that is characterized by acute inflammation and organ injury, and it is triggered by infections and noninfectious tissue injury, both of which activate innate immune receptors and pathways. Although reports suggest an anti-inflammatory role for the mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase 5 (ERK5), we previously found that ERK5 mediates proinflammatory responses in primary human cells in response to stimulation of Toll-like receptor 2 (TLR2). We inhibited the kinase activities and reduced the abundances of ERK5 and MEK5, a MAPK kinase directly upstream of ERK5, in primary human vascular endothelial cells and monocytes, and found that ERK5 promoted inflammation induced by a broad range of microbial TLR agonists and by the proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α).

Intravenous immunoglobulin skews macrophages to an anti-inflammatory, IL-10-producing activation state.

Intravenous Ig is used to treat autoimmune or autoinflammatory disorders, but the mechanism by which it exerts its immunosuppressive activity is not understood completely. To examine the impact of intravenous Ig on macrophages, we compared cytokine production by LPS-activated macrophages in the presence and absence of intravenous Ig. Intravenous Ig treatment induced robust production of IL-10 in response to LPS, relative to LPS stimulation alone, and reduced production of proinflammatory cytokines.

The endocannabinoid/endovanilloid N-arachidonoyl dopamine (NADA) and synthetic cannabinoid WIN55,212-2 abate the inflammatory activation of human endothelial cells.

Although cannabinoids, such as Δ(9)-tetrahydrocannabinol, have been studied extensively for their psychoactive effects, it has become apparent that certain cannabinoids possess immunomodulatory activity. Endothelial cells (ECs) are centrally involved in the pathogenesis of organ injury in acute inflammatory disorders, such as sepsis, because they express cytokines and chemokines, which facilitate the trafficking of leukocytes to organs, and they modulate vascular barrier function. In this study, we find that primary human ECs from multiple organs express the cannabinoid receptors CB1R, GPR18, and GPR55, as well as the ion channel transient receptor potential cation channel vanilloid type 1.

Sevoflurane induced amnesia inhibits hippocampal Arc expression partially through 5-hydroxytryptamine-7 receptors in the bilateral basolateral amygdala in rats.

This study aimed to investigate whether the regulation of 5-hydroxytryptamine-7 (5-HT7) receptors in the bilateral basolateral amygdala (BLA) could alter the amnesic effects of sevoflurane and change the hippocampal expression of Arc and neural apoptosis. Male Sprague-Dawley rats were randomized into ten groups. First, the animals received bilateral injection of SB269970 (20, 50, or 100 pmol/0.

Quantitative in vitro assay to measure neutrophil adhesion to activated primary human microvascular endothelial cells under static conditions.

The vascular endothelium plays an integral part in the inflammatory response. During the acute phase of inflammation, endothelial cells (ECs) are activated by host mediators or directly by conserved microbial components or host-derived danger molecules. Activated ECs express cytokines, chemokines and adhesion molecules that mobilize, activate and retain leukocytes at the site of infection or injury.

Alveolar macrophages and Toll-like receptor 4 mediate ventilated lung ischemia reperfusion injury in mice.

Background: Ischemia-reperfusion (I-R) injury is a sterile inflammatory process that is commonly associated with diverse clinical situations such as hemorrhage followed by resuscitation, transient embolic events, and organ transplantation. I-R injury can induce lung dysfunction whether the I-R occurs in the lung or in a remote organ. Recently, evidence has emerged that receptors and pathways of the innate immune system are involved in recognizing sterile inflammation and overlap considerably with those involved in the recognition of and response to pathogens.

ERK5 protein promotes, whereas MEK1 protein differentially regulates, the Toll-like receptor 2 protein-dependent activation of human endothelial cells and monocytes.

Endothelial cell (EC) Toll-like receptor 2 (TLR2) activation up-regulates the expression of inflammatory mediators and of TLR2 itself and modulates important endothelial functions, including coagulation and permeability. We defined TLR2 signaling pathways in EC and tested the hypothesis that TLR2 signaling differs in EC and monocytes. We found that ERK5, heretofore unrecognized as mediating TLR2 activation in any cell type, is a central mediator of TLR2-dependent inflammatory signaling in human umbilical vein endothelial cells, primary human lung microvascular EC, and human monocytes.

Effects of ghrelin on pulmonary NOD2 mRNA expression and NF-κB activation when protects against acute lung injury in rats challenged with cecal ligation and puncture.

Background: Many studies have shown that ghrelin can down-regulate inflammatory cytokine expression via the inhibition of NF-κB activity and therefore, its administration to septic patients is considered beneficial. However, our knowledge of ghrelin's effects on the upstream activators of the NF-κB pathway, such as NOD2, is still limited. This study aimed to investigate the possible involvement of the NOD2 signaling pathway in the anti-inflammatory effects of ghrelin.

Phosphorylation of threonine 1736 in the C-terminal tail of integrin β4 contributes to hemidesmosome disassembly.

During wound healing, hemidesmome disassembly enables keratinocyte migration and proliferation. Hemidesmosome dynamics are altered downstream of epidermal growth factor (EGF) receptor activation, following the phosphorylation of integrin β4 residues S1356 and S1364, which reduces the interaction with plectin; however, this event is insufficient to drive complete hemidesmome disassembly. In the studies reported here, we used a fluorescence resonance energy transfer-based assay to demonstrate that the connecting segment and carboxy-terminal tail of the β4 cytoplasmic domain interact, which facilitates the formation of a binding platform for plectin.

Activation of endothelial TLR2 by bacterial lipoprotein upregulates proteins specific for the neutrophil response.

The vascular endothelium is integrally involved in the host response to infection and in organ failure during acute inflammatory disorders such as sepsis. Gram-negative and Gram-positive bacterial lipoproteins circulate in sepsis and can directly activate the endothelium by binding to endothelial cell (EC) TLR2. In this report, we perform the most comprehensive analysis to date of the immune-related genes regulated after activation of endothelial TLR2 by bacterial di- and triacylated lipopeptides.

Bacterial lipoprotein TLR2 agonists broadly modulate endothelial function and coagulation pathways in vitro and in vivo.

TLR2 activation induces cellular and organ inflammation and affects lung function. Because deranged endothelial function and coagulation pathways contribute to sepsis-induced organ failure, we studied the effects of bacterial lipoprotein TLR2 agonists, including peptidoglycan-associated lipoprotein, Pam3Cys, and murein lipoprotein, on endothelial function and coagulation pathways in vitro and in vivo. TLR2 agonist treatment induced diverse human endothelial cells to produce IL-6 and IL-8 and to express E-selectin on their surface, including HUVEC, human lung microvascular endothelial cells, and human coronary artery endothelial cells.

EGF-induced MAPK signaling inhibits hemidesmosome formation through phosphorylation of the integrin {beta}4.

Migration of keratinocytes requires a regulated and dynamic turnover of hemidesmosomes (HDs). We and others have previously identified three serine residues on the integrin β4 cytoplasmic domain that play a critical role in the regulation of HD disassembly. In this study we show that only two of these residues (Ser-1356 and Ser-1364) are phosphorylated in keratinocytes after stimulation with either PMA or EGF.

Regulation of hemidesmosome disassembly by growth factor receptors.

Hemidesmosomes (HDs) promote the stable adhesion of basal epithelial cells to the underlying basement membrane (BM). Critical for the mechanical stability of the HD is the interaction between integrin alpha6beta4 and plectin, which is destabilized when HD disassembly is required, for instance, to allow keratinocyte migration during wound healing. Growth factors such as epidermal growth factor (EGF) can trigger HD disassembly and induce phosphorylation of the beta4 intracellular domain.

A RNA interference screen identifies the protein phosphatase 2A subunit PR55gamma as a stress-sensitive inhibitor of c-SRC.

Protein Phosphatase type 2A (PP2A) represents a family of holoenzyme complexes with diverse biological activities. Specific holoenzyme complexes are thought to be deregulated during oncogenic transformation and oncogene-induced signaling. Since most studies on the role of this phosphatase family have relied on the use of generic PP2A inhibitors, the contribution of individual PP2A holoenzyme complexes in PP2A-controlled signaling pathways is largely unclear.

Investigation into the mechanism regulating MRP localization.

The major PKC substrates MARCKS and MacMARCKS (MRP) are membrane-binding proteins implicated in cell spreading, integrin activation and exocytosis. According to the myristoyl-electrostatic switch model the co-operation between the myristoyl moiety and the positively charged effector domain (ED) is an essential mechanism by which proteins bind to membranes. Loss of the electrostatic interaction between the ED and phospholipids, such as Ptdins(4,5)P2, results in the translocation of such proteins to the cytoplasm.