Investigating the correlation of delirium after cardiac surgery with memories and posttraumatic stress disorder consequences of intensive care unit: A prospective cohort study.

OBJECTIVES: To explore the differences in post-intensive care unit memory and posttraumatic stress disorder symptoms between patients with and without delirium, and assess the correlations between the two. DESIGN: Prospective cohort observation study. SETTING: A cardiac intensive care unit of a tertiary hospital in China. We enrolled 318 consecutive patients after cardiac surgery between December 2017 and March 2019. MAIN OUTCOME MEASURES: Delirium was assessed using the Confusion Assessment Method for the ICU from intensive care unit admission to discharge. Intensive care unit memory was assessed using the ICU-Memory Tool through face-to-face interviews one week after discharge. Posttraumatic stress disorder was measured telephonically using the Impact of Events Scale-revised questionnaire at three months post-discharge. RESULTS: Eighty patients each in the delirium and non-delirium groups were enrolled for follow-up interviews. Patients with delirium had vaguer memories of pre-intensive care unit admission and of their stay, and recollected more memories of feelings (vs. without delirium). Posttraumatic stress disorder was diagnosed in 14 patients with and in seven without delirium, with non-significant differences between groups. Delirium did not influence post-intensive care unit factual, feeling, and delusional memories, nor posttraumatic stress disorder and hyperarousal, intrusion, and avoidance. The memories of feelings were positively correlated with the last three (r = 0.285, r = 0.390 and r = 0.373, respectively). CONCLUSION: Patients with delirium had vague intensive care unit memories. Memories of feelings were positively correlated with symptoms of hyperarousal, intrusion, and avoidance. Delirium did not influence factual, feeling, or delusional memories nor posttraumatic stress disorder incidence and symptoms. IMPLICATIONS FOR CLINICAL PRACTICE: Interventions are needed to reduce the impact of vague memory in patients with post-intensive care unit delirium. Memories of feelings should be focused on because of their correlation with hyperarousal, intrusion, and avoidance. Delirium prevention and early recognition measures are suggested.

A multifunctional switching bidirectional optical absorber based on a titanium nitride metamaterial.

In this paper, a novel type of tunable ultra-wide band and double-narrow band artificial electromagnetic absorption device is studied. This work uses a titanium nitride-titanium-tungsten (TiN-Ti-W) composite ring array, a TiN reflector layer, and a silver-titanium dioxide-silver (Ag-TiO2-Ag) three layer composite structure to prepare the absorption layer. The simulation results illustrate that the absorption rate can reach 96.6% when the absorption wavelength is 300-2800 nm. When the light source is backward incidence, ultra-narrow band absorption can occur at specific wavelengths of 465 nm and 932 nm. This proves that the absorber is in good agreement with the impedance matching theory. The research results of this work will provide a theoretical basis for the design and application of solar thermal energy conversion.

Metamaterial ultra-wideband solar absorbers based on a multi-layer structure with cross etching.

In this paper, we design a solar absorber based on the Si3N4-W-Ti-SiO2 insulator-metal-insulator structure and demonstrate it using the finite difference time domain (FDTD) method. The absorption rate of the absorber consisting of a multi-layer structure with cross etching is over 90% in the bandwidth of 500 nm to 2995 nm with an average absorption rate of 98.3%. There are three peaks at 620 nm, 1002 nm and 1761 nm with peak heights of 99.8%, 99.8% and 99.0%, respectively. By analyzing the distribution of electric and magnetic fields in different sections of the absorber, it is found that the physical mechanism of the structure with high absorptivity is due to the interaction of propagating surface plasmon resonance and local surface plasma resonance. The effects of different structural parameters and the angle of incidence of a light source on the absorber absorption are discussed. The absorber can be used in solar thermal systems, thermal photovoltaics and thermoelectronic devices.

Plasma biomarkers and delirium in critically ill patients after cardiac surgery: A prospective observational cohort study.

BACKGROUND: Delirium is common in postoperative critically ill patients and may affect by intraoperative events. Biomarkers are vital indicators in the development and prediction of delirium. OBJECTIVES: This study aimed to investigate the associations between various plasma biomarkers and delirium. METHODS: We performed a prospective cohort study on cardiac surgery patients. Delirium assessment was performed twice daily using the confusion assessment method for the intensive care unit (ICU), and the Richmond Agitation Sedation Scale was used to assess the depth of sedation and agitation. Blood samples were collected on the day after ICU admission, and the concentrations of cortisol, interleukin (IL)-1ß, IL-6, tumor necrosis factor α, soluble tumor necrosis factor receptor-1 (sTNFR-1), and sTNFR-2 were measured. RESULTS: Delirium in the ICU was noted in 93 (29.2%, 95% CI 24.2-34.3) out of 318 patients (mean age 52 years, SD 12.0). The longer duration of cardiopulmonary bypass, aortic clamping and surgery, and higher plasma, erythrocytes, and platelet transfusion requirements were among the significant differences in intraoperative events between patients with and without delirium. Median levels of IL-6 (p = 0.017), TNF-α (p = 0.048), sTNFR-1 (p < 0.001), and sTNFR-2 (p = 0.001) were significantly higher in patients with delirium than in those without it. After adjusting for demographic variables and intraoperative events, only sTNFR-1 (odds ratio 6.83, 95% CI: 1.14-40.90) was associated with delirium. CONCLUSIONS: Plasma IL-6, TNF-α, sTNFR-1, and sTNFR-2 levels were higher in ICU-acquired delirium patients after cardiac surgery. sTNFR-1 was a potential indicator of the disorder.

Obesity caused by an OVOL2 mutation reveals dual roles of OVOL2 in promoting thermogenesis and limiting white adipogenesis.

Using random germline mutagenesis in mice, we identified a viable hypomorphic allele (boh) of the transcription-factor-encoding gene Ovol2 that resulted in obesity, which initially developed with normal food intake and physical activity but decreased energy expenditure. Fat weight was dramatically increased, while lean weight was reduced in 12-week-old boh homozygous mice, culminating by 24 weeks in massive obesity, hepatosteatosis, insulin resistance, and diabetes. The Ovol2boh/boh genotype augmented obesity in Lepob/ob mice, and pair-feeding failed to normalize obesity in Ovol2boh/boh mice. OVOL2-deficient mice were extremely cold intolerant. OVOL2 is essential for brown/beige adipose tissue-mediated thermogenesis. In white adipose tissues, OVOL2 limited adipogenesis by blocking C/EBPα engagement of its transcriptional targets. Overexpression of OVOL2 in adipocytes of mice fed with a high-fat diet reduced total body and liver fat and improved insulin sensitivity. Our data reveal that OVOL2 plays dual functions in thermogenesis and adipogenesis to maintain energy balance.

Improving emulsifying properties of carboxylated microcrystalline cellulose by calcium bridging to hydrophobic peptides.

This study aimed to improve the emulsifying properties of microcrystalline cellulose by carboxylating (CC) and bridging to hydrophobic oat globule peptides (HP) via Ca2+ (CC-Ca-HP). FTIR and XRD spectra analysis proved the successful attachment of HP to CC through a salt bridge. The Ca2+-bridging significantly changed the particle characteristics of CC-Ca-HP, including particle size, ζ-potential, and wettability. The Ca2+-bridged composite CC-Ca-HP demonstrated remarkable emulsifying stability compared with the nonbridged blend (CC-HP). Further analysis of the steady flow characteristics and dynamic viscoelastic properties revealed a network structure formed in the CC-Ca-HP emulsion. Moreover, the CC-Ca-HP emulsion showed a marked release of free fatty acids, increased bioaccessibility of zeaxanthin in the simulated gastrointestinal digestion, and less oil oxidation under the accelerated oxidation condition, indicating that the stable structure of CC-Ca-HP imparted by Ca2+-bridging prevented the aggregation of oil droplets as collision occurred under the harsh gastric conditions.

Risk factors for inadvertent intraoperative hypothermia in patients undergoing laparoscopic surgery: A prospective cohort study.

BACKGROUND: Inadvertent intraoperative hypothermia is frequent during open surgeries; however, few studies on hypothermia during laparoscopic abdominal surgery have been reported. We aimed to investigate the incidence and risk factors for hypothermia in patients undergoing laparoscopic abdominal surgery. METHODS: This single-center prospective cohort observational study involved patients undergoing laparoscopic surgery between October 2018 and June 2019. Data on core body temperature and potential variables were collected. A multivariate logistic regression analysis was performed to identify the risk factors associated with hypothermia. A Cox regression analysis was used to verify the sensitivity of the results. RESULTS: In total, 690 patients were included in the analysis, of whom 200 (29.0%, 95% CI: 26%-32%) had a core temperature < 36°C. The core temperature decreased over time, and the incident hypothermia increased gradually. In the multivariate logistic regression analysis, age (OR = 1.017, 95% CI: 1.000-1.034, P = 0.050), BMI (OR = 0.938, 95% CI: 0.880-1.000; P = 0.049), baseline body temperature (OR = 0.025, 95% CI: 0.010-0.060; P < 0.001), volume of irrigation fluids (OR = 1.001, 95% CI: 1.000-1.001, P = 0.001), volume of urine (OR = 1.001, 95% CI: 1.000-1.003, P = 0.070), and duration of surgery (OR = 1.010, 95% CI: 1.006-1.015, P < 0.001) were significantly associated with hypothermia. In the Cox analysis, variables in the final model were age, BMI, baseline body temperature, volume of irrigation fluids, blood loss, and duration of surgery. CONCLUSIONS: Inadvertent intraoperative hypothermia is evident in patients undergoing laparoscopic surgeries. Age, BMI, baseline body temperature, volume of irrigation fluids, and duration of surgery are significantly associated with intraoperative hypothermia.

Thousands of induced germline mutations affecting immune cells identified by automated meiotic mapping coupled with machine learning.

Forward genetic studies use meiotic mapping to adduce evidence that a particular mutation, normally induced by a germline mutagen, is causative of a particular phenotype. Particularly in small pedigrees, cosegregation of multiple mutations, occasional unawareness of mutations, and paucity of homozygotes may lead to erroneous declarations of cause and effect. We sought to improve the identification of mutations causing immune phenotypes in mice by creating Candidate Explorer (CE), a machine-learning software program that integrates 67 features of genetic mapping data into a single numeric score, mathematically convertible to the probability of verification of any putative mutation-phenotype association. At this time, CE has evaluated putative mutation-phenotype associations arising from screening damaging mutations in ∼55% of mouse genes for effects on flow cytometry measurements of immune cells in the blood. CE has therefore identified more than half of genes within which mutations can be causative of flow cytometric phenovariation in Mus musculus The majority of these genes were not previously known to support immune function or homeostasis. Mouse geneticists will find CE data informative in identifying causative mutations within quantitative trait loci, while clinical geneticists may use CE to help connect causative variants with rare heritable diseases of immunity, even in the absence of linkage information. CE displays integrated mutation, phenotype, and linkage data, and is freely available for query online.

Sulfatides are endogenous ligands for the TLR4-MD-2 complex.

Many endogenous molecules, mostly proteins, purportedly activate the Toll-like receptor 4 (TLR4)-myeloid differentiation factor-2 (MD-2) complex, the innate immune receptor for lipopolysaccharide (LPS) derived from gram-negative bacteria. However, there is no structural evidence supporting direct TLR4-MD-2 activation by endogenous ligands. Sulfatides (3-O-sulfogalactosylceramides) are natural, abundant sulfated glycolipids that have variously been shown to initiate or suppress inflammatory responses. We show here that short fatty acid (FA) chain sulfatides directly activate mouse TLR4-MD-2 independent of CD14, trigger MyD88- and TRIF-dependent signaling, and stimulate tumor necrosis factor α (TNFα) and type I interferon (IFN) production in mouse macrophages. In contrast to the agonist activity toward the mouse receptor, the tested sulfatides antagonize TLR4-MD-2 activation by LPS in human macrophage-like cells. The agonistic and antagonistic activities of sulfatides require the presence of the sulfate group and are inversely related to the FA chain length. The crystal structure of mouse TLR4-MD-2 in complex with C16-sulfatide revealed that three C16-sulfatide molecules bound to the MD-2 hydrophobic pocket and induced an active dimer conformation of the receptor complex similar to that induced by LPS or lipid A. The three C16-sulfatide molecules partially mimicked the detailed interactions of lipid A to achieve receptor activation. Our results suggest that sulfatides may mediate sterile inflammation or suppress LPS-stimulated inflammation, and that additional endogenous negatively charged lipids with up to six lipid chains of limited length might also bind to TLR4-MD-2 and activate or inhibit this complex.

SLFN2 protection of tRNAs from stress-induced cleavage is essential for T cell-mediated immunity.

Reactive oxygen species (ROS) increase in activated T cells because of metabolic activity induced to support T cell proliferation and differentiation. We show that these ROS trigger an oxidative stress response that leads to translation repression. This response is countered by Schlafen 2 (SLFN2), which directly binds transfer RNAs (tRNAs) to protect them from cleavage by the ribonuclease angiogenin. T cell-specific SLFN2 deficiency results in the accumulation of tRNA fragments, which inhibit translation and promote stress-granule formation. Interleukin-2 receptor ß (IL-2Rß) and IL-2Rγ fail to be translationally up-regulated after T cell receptor stimulation, rendering SLFN2-deficient T cells insensitive to interleukin-2's mitogenic effects. SLFN2 confers resistance against the ROS-mediated translation-inhibitory effects of oxidative stress normally induced by T cell activation, permitting the robust protein synthesis necessary for T cell expansion and immunity.

Adenosine monophosphate deaminase 3 null mutation causes reduction of naive T cells in mouse peripheral blood.

Adenosine monophosphate deaminase 3 (Ampd3) encodes the erythrocyte isoform of the adenosine monophosphate (AMP) deaminase gene family. Mutations in this gene have been reported in humans, leading to autosomal-recessive erythrocyte AMP deaminase deficiency. However, the mutation is considered clinically asymptomatic. Using N-ethyl-N-nitrosourea mutagenesis to find mutations that affect peripheral lymphocyte populations, we identified 5 Ampd3 mutations (Ampd3guangdong, Ampd3carson, Ampd3penasco, Ampd3taos, and Ampd3commanche) that strongly correlated with a reduction in naive CD4+ T and naive CD8+ T-cell populations. Causation was confirmed by targeted ablation of Ampd3. Knockout mice had reduced frequencies of CD62LhiCD44lo CD4+ naive and CD8+ naive T cells. Interestingly, these phenotypes were restricted to T cells circulating in peripheral blood and were not seen in T cells from secondary lymphoid organs (lymph nodes and spleen). We found that reduction of naive T cells in the peripheral blood of Ampd3-/- mice was caused by T-cell-extrinsic factor(s), which we hypothesize to be elevated levels of adenosine triphosphate released by Ampd3-deficient erythrocytes. These findings provide an example in which disruption of an erythrocyte-specific protein can affect the physiological status of lymphocytes in peripheral blood.

Efficacy of nanoparticle encapsulation on suppressing oxidation and enhancing antifungal activity of cyclic lipopeptides produced by Bacillus subtilis.

This study examined the storage instability of cyclic lipopeptides (CLs) extracted from Bacillus subtilis culture; CLs were easily oxidized and therefore quickly lost antifungal activity during storage. Solid lipid nanoparticle (SLN) encapsulation effectively suppressed the oxidation and prolonged and enhanced the antifungal efficacy of CLs through controlled release. Thermal gravimetric analysis, X-ray diffraction, and Fourier transform infrared spectroscopy revealed that hydrophobic interactions between the fatty acid moieties of CLs and SLNs fortified the crystal structure of the CL-SLN complex, thereby improving the storage stability of the encapsulated CLs. Furthermore, the encapsulated CLs also demonstrated more potent antifungal activity than free CLs in damaging fungal cellular membranes, affecting the growth of hyphae and spores, and decreasing ochratoxin A levels. SLN encapsulation is an effective method to protect and improve the function of CLs.

Genetic and structural studies of RABL3 reveal an essential role in lymphoid development and function.

The small GTPase RABL3 is an oncogene of unknown physiological function. Homozygous knockout alleles of mouse Rabl3 were embryonic lethal, but a viable hypomorphic allele (xiamen [xm]) causing in-frame deletion of four amino acids from the interswitch region resulted in profound defects in lymphopoiesis. Impaired lymphoid progenitor development led to deficiencies of B cells, T cells, and natural killer (NK) cells in Rabl3xm/xm mice. T cells and NK cells exhibited impaired cytolytic activity, and mice infected with mouse cytomegalovirus (MCMV) displayed elevated titers in the spleen. Myeloid cells were normal in number and function. Biophysical and crystallographic studies demonstrated that RABL3 formed a homodimer in solution via interactions between the effector binding surfaces on each subunit; monomers adopted a typical small G protein fold. RABL3xm displayed a large compensatory alteration in switch I, which adopted a ß-strand configuration normally provided by the deleted interswitch residues, thereby permitting homodimer formation. Dysregulated effector binding due to conformational changes in the switch I-interswitch-switch II module likely underlies the xm phenotype. One such effector may be GPR89, putatively an ion channel or G protein-coupled receptor (GPCR). RABL3, but not RABL3xm, strongly associated with and stabilized GPR89, and an N-ethyl-N-nitrosourea (ENU)-induced mutation (explorer) in Gpr89 phenocopied Rabl3xm.

Mutual inhibition between Prkd2 and Bcl6 controls T follicular helper cell differentiation.

T follicular helper cells (TFH) participate in germinal center (GC) development and are necessary for B cell production of high-affinity, isotype-switched antibodies. In a forward genetic screen, we identified a missense mutation in Prkd2, encoding the serine/threonine kinase protein kinase D2, which caused elevated titers of immunoglobulin E (IgE) in the serum. Subsequent analysis of serum antibodies in mice with a targeted null mutation of Prkd2 demonstrated polyclonal hypergammaglobulinemia of IgE, IgG1, and IgA isotypes, which was exacerbated by the T cell-dependent humoral response to immunization. GC formation and GC B cells were increased in Prkd2-/- spleens. These effects were the result of excessive cell-autonomous TFH development caused by unrestricted Bcl6 nuclear translocation in Prkd2-/- CD4+ T cells. Prkd2 directly binds to Bcl6, and Prkd2-dependent phosphorylation of Bcl6 is necessary to constrain Bcl6 to the cytoplasm, thereby limiting TFH development. In response to immunization, Bcl6 repressed Prkd2 expression in CD4+ T cells, thereby committing them to TFH development. Thus, Prkd2 and Bcl6 form a mutually inhibitory positive feedback loop that controls the stable transition from naïve CD4+ T cells to TFH during the adaptive immune response.

Essential cell-extrinsic requirement for PDIA6 in lymphoid and myeloid development.

In a forward genetic screen of N-ethyl-N-nitrosourea (ENU)-induced mutant mice for aberrant immune function, we identified mice with a syndromic disorder marked by growth retardation, diabetes, premature death, and severe lymphoid and myeloid hypoplasia together with diminished T cell-independent (TI) antibody responses. The causative mutation was in Pdia6, an essential gene encoding protein disulfide isomerase A6 (PDIA6), an oxidoreductase that functions in nascent protein folding in the endoplasmic reticulum. The immune deficiency caused by the Pdia6 mutation was, with the exception of a residual T cell developmental defect, completely rescued in irradiated wild-type recipients of PDIA6-deficient bone marrow cells, both in the absence or presence of competition. The viable hypomorphic allele uncovered in these studies reveals an essential role for PDIA6 in hematopoiesis, but one extrinsic to cells of the hematopoietic lineage. We show evidence that this role is in the proper folding of Wnt3a, BAFF, IL-7, and perhaps other factors produced by the extra-hematopoietic compartment that contribute to the development and lineage commitment of hematopoietic cells.

Short peptides secreted by Bacillus subtilis inhibit the growth of mold on fresh-cut pumpkin (Cucurbita pepo).

BACKGROUND: This study investigates the efficacy of short peptides secreted by Bacillus subtilis for fungal inhibition in fresh-cut pumpkin and for maintaining its shelf life. RESULTS: Low-molecular-weight filtrate (LC < 1000 Da) of B. subtilis culture (BC) significantly lowered the total number of molds on fresh-cut pumpkin compared with the untreated control and a BC group after storage. Low-molecular-weight filtrate prevented the deterioration of sensory quality in a pumpkin incision, and reduced pectinase activity. It also inhibited the growth of Phytophthora capsici and Penicillium chrysogenum, and the activity of ß-1,3-glucan synthase (GS) secreted by both molds. Fifty-seven GS-inhibiting peptides were screened from 95 LC peptides with two to five amino acid residues. The two most potent peptides, AWYW and HWWY, had strongly suppressive effects on the growth of P. capsici and P. chrysogenum. CONCLUSION: Our study demonstrated that short peptides present in B. subtilis culture can play an important role in the maintenance of fresh-cut pumpkin by suppressing fungal growth. © 2019 Society of Chemical Industry.

[Risk factors for intensive care unit delirium after cardiac operation].

OBJECTIVE: To analyze the risk factors of delirium in patients in cardiac surgery intensive care unit (CSICU). METHODS: A prospective observational study was performed. Patients admitted to CSICU of Fujian Medical University Union Hospital from March to August in 2017 were enrolled. The combination of the Richmond agitation sedation scale (RASS) and the ICU-confusion assessment method (CAM-ICU) were used to evaluate delirium. The patient was assessed on the second day after CSICU admission, twice a day, the evaluation was stopped, and the follow-up observation was terminated after the patient was discharged from CSICU. The patients were divided into two groups according to whether delirium occurred in CSICU. The general and clinical treatment data (including condition, operation, anesthesia and CSICU treatment) of the two groups were compared. The related factors of delirium were identified by univariate analysis and multifactor Logistic regression analysis. RESULTS: A total of 318 cases were included in this study. Among them, 93 cases had delirium and the incidence of delirium was 29.2%. It was shown by univariate analysis that age, history of hypertension, type of surgery, surgical procedure, American Society of Anesthesiologists (ASA) anesthesia classification, usage of propofol, plasma transfusion, red blood cells, platelet transfusion, blood loss, operative time, cardiopulmonary bypass (CPB) time, myocardial block time, acute physiology and chronic health evaluation II (APACHE II), duration of mechanical ventilation, the length of intensive care unit (ICU) stay, postoperative usage of diazepam, midazolam, fentanyl, morphine, chlorpromazine, etc. which were related to delirium, and occupation (on-the-job or self-employed), medical insurance (city or provincial medical insurance), education (primary to junior high school, high school or above) could reduce the risk of delirium. Colinearity diagnosis was performed on variables with statistically significant differences, and variables with variance expansion factor (VIF) < 3 were included in multivariate Logistic regression analysis. The results showed that age, education level, type of surgery, ASA classification, CPB time, APACHE II, ICU mechanical ventilation time, and post operation usage of midazolam were independently related to delirium [age: odds ratio (OR) = 1.625, 95% confidence interval (95%CI) = 1.303-2.026; education level: OR = 0.293, 95%CI = 0.171-0.504; type of surgery: OR = 2.194, 95%CI = 1.052-4.576; ASA classification: OR = 1.916, 95%CI = 1.032-3.559; CPB time: OR = 2.125, 95%CI = 1.105-4.088; APACHE II: OR = 2.091, 95%CI = 1.005-4.349; ICU mechanical ventilation time: OR = 1.943, 95%CI = 1.269-2.975; midazolam: OR = 2.653, 95%CI = 1.328-5.299; all P < 0.05], among which, high education level has a good protective effect on delirium. CONCLUSIONS: Age, type of surgery, ASA classification, CPB time, APACHE II, ICU mechanical ventilation time, post operation usage of midazolam were independent risk factors for delirium, and high education level had a good protective effect. Among them, the educational level, CPB time, duration of mechanical ventilation, and midazolam are intervention factors. In clinical treatment, not only the risk factors should be identified, but also intervention should be taken to prevent the occurrence of delirium.

Structural Basis of TLR2/TLR1 Activation by the Synthetic Agonist Diprovocim.

Diprovocim is a recently discovered exceptionally potent, synthetic small molecule agonist of TLR2/TLR1 and has shown significant adjuvant activity in anticancer vaccination against murine melanoma. Since Diprovocim bears no structural similarity to the canonical lipopeptide ligands of TLR2/TLR1, we investigated how Diprovocim interacts with TLR2/TLR1 through in vitro biophysical, structural, and computational approaches. We found that Diprovocim induced the formation of TLR2/TLR1 heterodimers as well as TLR2 homodimers in vitro. We determined the crystal structure of Diprovocim in a complex with a TLR2 ectodomain, which revealed, unexpectedly, two Diprovocim molecules bound to the ligand binding pocket formed between two TLR2 ectodomains. Extensive hydrophobic interactions and a hydrogen-bonding network between the protein and Diprovocim molecules are observed within the defined ligand binding pocket and likely underlie the high potency of Diprovocim. Our work shed first light into the activation mechanism of TLR2/TLR1 by a noncanonical agonist. The structural information obtained here may be exploited to manipulate TLR2/TLR1-dependent signaling.

Diprovocims: A New and Exceptionally Potent Class of Toll-like Receptor Agonists.

A screen conducted with nearly 100000 compounds and a surrogate functional assay for stimulation of an immune response that measured the release of TNF-α from treated human THP-1 myeloid cells differentiated along the macrophage line led to the discovery of the diprovocims. Unique to these efforts and of special interest, the screening leads for this new class of activators of an immune response came from a compound library designed to promote cell-surface receptor dimerization. Subsequent comprehensive structure-activity relationship studies improved the potency 800-fold over that of the screening leads, providing diprovocim-1 and diprovocim-2. The diprovocims act by inducing cell-surface toll-like receptor (TLR)-2 dimerization and activation with TLR1 (TLR1/TLR2 agonist), bear no structural similarity to any known natural or synthetic TLR agonist, and are easy to prepare and synthetically modify, and selected members are active in both human and murine systems. The most potent diprovocim (3, diprovocim-1) elicits full agonist activity at extraordinarily low concentrations (EC50 = 110 pM) in human THP-1 cells, being more potent than the naturally derived TLR1/TLR2 agonist Pam3CSK4 or any other known small molecule TLR agonist.