Browsing by Subject "Toll-Like Receptors"
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Item Open Access DAMPs/PAMPs induce monocytic TLR activation and tolerance in COVID-19 patients; nucleic acid binding scavengers can counteract such TLR agonists.(Biomaterials, 2022-04) Naqvi, Ibtehaj; Giroux, Nicholas; Olson, Lyra; Morrison, Sarah Ahn; Llanga, Telmo; Akinade, Tolu O; Zhu, Yuefei; Zhong, Yiling; Bose, Shree; Arvai, Stephanie; Abramson, Karen; Chen, Lingye; Que, Loretta; Kraft, Bryan; Shen, Xiling; Lee, Jaewoo; Leong, Kam W; Nair, Smita K; Sullenger, BruceMillions of COVID-19 patients have succumbed to respiratory and systemic inflammation. Hyperstimulation of toll-like receptor (TLR) signaling is a key driver of immunopathology following infection by viruses. We found that severely ill COVID-19 patients in the Intensive Care Unit (ICU) display hallmarks of such hyper-stimulation with abundant agonists of nucleic acid-sensing TLRs present in their blood and lungs. These nucleic acid-containing Damage and Pathogen Associated Molecular Patterns (DAMPs/PAMPs) can be depleted using nucleic acid-binding microfibers to limit the patient samples' ability to hyperactivate such innate immune receptors. Single-cell RNA-sequencing revealed that CD16+ monocytes from deceased but not recovered ICU patients exhibit a TLR-tolerant phenotype and a deficient anti-viral response after ex vivo TLR stimulation. Plasma proteomics confirmed such myeloid hyperactivation and revealed DAMP/PAMP carrier consumption in deceased patients. Treatment of these COVID-19 patient samples with MnO nanoparticles effectively neutralizes TLR activation by the abundant nucleic acid-containing DAMPs/PAMPs present in their lungs and blood. Finally, MnO nanoscavenger treatment limits the ability of DAMPs/PAMPs to induce TLR tolerance in monocytes. Thus, treatment with microfiber- or nanoparticle-based DAMP/PAMP scavengers may prove useful for limiting SARS-CoV-2 induced hyperinflammation, preventing monocytic TLR tolerance, and improving outcomes in severely ill COVID-19 patients.Item Open Access Genetic variant of IRAK2 in the toll-like receptor signaling pathway and survival of non-small cell lung cancer.(International journal of cancer, 2018-11) Xu, Yinghui; Liu, Hongliang; Liu, Shun; Wang, Yanru; Xie, Jichun; Stinchcombe, Thomas E; Su, Li; Zhang, Ruyang; Christiani, David C; Li, Wei; Wei, QingyiThe toll-like receptor (TLR) signaling pathway plays an important role in the innate immune responses and antigen-specific acquired immunity. Aberrant activation of the TLR pathway has a significant impact on carcinogenesis or tumor progression. Therefore, we hypothesize that genetic variants in the TLR signaling pathway genes are associated with overall survival (OS) of patients with non-small cell lung cancer (NSCLC). To test this hypothesis, we first performed Cox proportional hazards regression analysis to evaluate associations between genetic variants of 165 TLR signaling pathway genes and NSCLC OS using the genome-wide association study (GWAS) dataset from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO). The results were further validated by the Harvard Lung Cancer Susceptibility GWAS dataset. Specifically, we identified IRAK2 rs779901 C > T as a predictor of NSCLC OS, with a variant-allele (T) attributed hazards ratio (HR) of 0.78 [95% confidence interval (CI) = 0.67-0.91, P = 0.001] in the PLCO dataset, 0.84 (0.72-0.98, 0.031) in the Harvard dataset, and 0.81 (0.73-0.90, 1.08x10-4 ) in the meta-analysis of these two GWAS datasets. In addition, the T allele was significantly associated with an increased mRNA expression level of IRAK2. Our findings suggest that IRAK2 rs779901 C > T may be a promising prognostic biomarker for NSCLC OS.Item Open Access PAMPs and DAMPs: signal 0s that spur autophagy and immunity.(Immunological reviews, 2012-09) Tang, Daolin; Kang, Rui; Coyne, Carolyn B; Zeh, Herbert J; Lotze, Michael TPathogen-associated molecular pattern molecules (PAMPs) are derived from microorganisms and recognized by pattern recognition receptor (PRR)-bearing cells of the innate immune system as well as many epithelial cells. In contrast, damage-associated molecular pattern molecules (DAMPs) are cell-derived and initiate and perpetuate immunity in response to trauma, ischemia, and tissue damage, either in the absence or presence of pathogenic infection. Most PAMPs and DAMPs serve as so-called 'Signal 0s' that bind specific receptors [Toll-like receptors, NOD-like receptors, RIG-I-like receptors, AIM2-like receptors, and the receptor for advanced glycation end products (RAGE)] to promote autophagy. Autophagy, a conserved lysosomal degradation pathway, is a cell survival mechanism invoked in response to environmental and cellular stress. Autophagy is inferred to have been present in the last common eukaryotic ancestor and only to have been lost by some obligatory intracellular parasites. As such, autophagy represents a unifying biology, subserving survival and the earliest host defense strategies, predating apoptosis, within eukaryotes. Here, we review recent advances in our understanding of autophagic molecular mechanisms and functions in emergent immunity.Item Open Access Sex-Specific Effects of Progesterone on Early Outcome of Intracerebral Hemorrhage.(Neuroendocrinology, 2016-01) Hsieh, Justin T; Lei, Beilei; Sheng, Huaxin; Venkatraman, Talagnair; Lascola, Christopher D; Warner, David S; James, Michael LBackground
Preclinical evidence suggests that progesterone improves recovery after intracerebral hemorrhage (ICH); however, gonadal hormones have sex-specific effects. Therefore, an experimental model of ICH was used to assess recovery after progesterone administration in male and female rats.Methods
ICH was induced in male and female Wistar rats via stereotactic intrastriatal injection of clostridial collagenase (0.5 U). Animals were randomized to receive vehicle or 8 mg/kg progesterone intraperitoneally at 2 h, then subcutaneously at 5, 24, 48, and 72 h after injury. Outcomes included relevant physiology during the first 3 h, hemorrhage and edema evolution over the first 24 h, proinflammatory transcription factor and cytokine regulation at 24 h, rotarod latency and neuroseverity score over the first 7 days, and microglial activation/macrophage recruitment at 7 days after injury.Results
Rotarod latency (p = 0.001) and neuroseverity score (p = 0.01) were improved in progesterone-treated males, but worsened in progesterone-treated females (p = 0.028 and p = 0.008, respectively). Progesterone decreased cerebral edema (p = 0.04), microglial activation/macrophage recruitment (p < 0.001), and proinflammatory transcription factor phosphorylated nuclear factor-x03BA;B p65 expression (p = 0.0038) in males but not females, independent of tumor necrosis factor-α, interleukin-6, and toll-like receptor-4 expression. Cerebral perfusion was increased in progesterone-treated males at 4 h (p = 0.043) but not 24 h after injury. Hemorrhage volume, arterial blood gases, glucose, and systolic blood pressure were not affected.Conclusions
Progesterone administration improved early neurobehavioral recovery and decreased secondary neuroinflammation after ICH in male rats. Paradoxically, progesterone worsened neurobehavioral recovery and did not modify neuroinflammation in female rats. Future work should isolate mechanisms of sex-specific progesterone effects after ICH.Item Open Access The Immunology of Syncytialized Trophoblast.(International journal of molecular sciences, 2021-02) Schust, Danny J; Bonney, Elizabeth A; Sugimoto, Jun; Ezashi, Toshi; Roberts, R Michael; Choi, Sehee; Zhou, JieMultinucleate syncytialized trophoblast is found in three forms in the human placenta. In the earliest stages of pregnancy, it is seen at the invasive leading edge of the implanting embryo and has been called primitive trophoblast. In later pregnancy, it is represented by the immense, multinucleated layer covering the surface of placental villi and by the trophoblast giant cells found deep within the uterine decidua and myometrium. These syncytia interact with local and/or systemic maternal immune effector cells in a fine balance that allows for invasion and persistence of allogeneic cells in a mother who must retain immunocompetence for 40 weeks of pregnancy. Maternal immune interactions with syncytialized trophoblast require tightly regulated mechanisms that may differ depending on the location of fetal cells and their invasiveness, the nature of the surrounding immune effector cells and the gestational age of the pregnancy. Some specifically reflect the unique mechanisms involved in trophoblast cell-cell fusion (aka syncytialization). Here we will review and summarize several of the mechanisms that support healthy maternal-fetal immune interactions specifically at syncytiotrophoblast interfaces.Item Open Access The transcriptomic response of rat hepatic stellate cells to endotoxin: implications for hepatic inflammation and immune regulation.(PloS one, 2013-01) Harvey, Stephen AK; Dangi, Anil; Tandon, Ashish; Gandhi, Chandrashekhar RWith their location in the perisinusoidal space of Disse, hepatic stellate cells (HSCs) communicate with all of the liver cell types both by physical association (cell body as well as cytosolic processes penetrating into sinusoids through the endothelial fenestrations) and by producing several cytokines and chemokines. Bacterial lipopolysaccharide (LPS), circulating levels of which are elevated in liver diseases and transplantation, stimulates HSCs to produce increased amounts of cytokines and chemokines. Although recent research provides strong evidence for the role of HSCs in hepatic inflammation and immune regulation, the number of HSC-elaborated inflammatory and immune regulatory molecules may be much greater then known at the present time. Here we report time-dependent changes in the gene expression profile of inflammatory and immune-regulatory molecules in LPS-stimulated rat HSCs, and their validation by biochemical analyses. LPS strongly up-regulated LPS-response elements (TLR2 and TLR7) but did not affect TLR4 and down-regulated TLR9. LPS also up-regulated genes in the MAPK, NFκB, STAT, SOCS, IRAK and interferon signaling pathways, numerous CC and CXC chemokines and IL17F. Interestingly, LPS modulated genes related to TGFβ and HSC activation in a manner that would limit their activation and fibrogenic activity. The data indicate that LPS-stimulated HSCs become a major cell type in regulating hepatic inflammatory and immunological responses by altering expression of numerous relevant genes, and thus play a prominent role in hepatic pathophysiology including liver diseases and transplantation.Item Open Access Unc93b Induces Apoptotic Cell Death and Is Cleaved by Host and Enteroviral Proteases.(PloS one, 2015-01) Harris, Katharine G; Coyne, Carolyn BUnc93b is an endoplasmic reticulum (ER)-resident transmembrane protein that serves to bind and traffic toll-like receptors (TLRs) from the ER to their appropriate subcellular locations for ligand sensing. Because of its role in TLR trafficking, Unc93b is necessary for an effective innate immune response to coxsackievirus B3 (CVB), a positive-sense single stranded RNA virus belonging to the enterovirus family. Here, we show that Unc93b is cleaved by a CVB-encoded cysteine protease (3Cpro) during viral replication. Further, we define a role for Unc93b in the induction of apoptotic cell death and show that expression of wild-type Unc93b, but not a mutant incapable of binding TLRs or exiting the ER (H412R), induces apoptosis. Furthermore, we show that cellular caspases activated during apoptosis directly cleave Unc93b. Interestingly, we show that the 3Cpro- and caspase-mediated cleavage of Unc93b both occur within ten amino acids in the distal N-terminus of Unc93b. Mechanistically, neither caspase-mediated nor 3Cpro-mediated cleavage of Unc93b altered its trafficking function, inhibited its role in facilitating TLR3 or TLR8 signaling, or altered its apoptosis-inducing effects. Taken together, our studies show that Unc93b is targeted by both viral- and host cell-specific proteases and identify a function of Unc93b in the induction of apoptotic cell death.