TLR3 Ligand PolyI:C Prevents Acute Pancreatitis Through the Interferon-β/Interferon-α/β Receptor Signaling Pathway in a Caerulein-Induced Pancreatitis Mouse Model

Acute pancreatitis (AP) is a common and devastating inflammatory disorder of the pancreas. However, there are still no effective treatments available for the disease. Therefore, it is important to discover new therapeutic targets and strategies for better treatment and prognosis of AP patients. Toll-like receptor 3 (TLR3) ligand polyI:C is a double-stranded RNA mimic that can be used as an immune stimulant. Our current study indicates that polyI:C exerted excellent anti-inflammatory effects in a caerulein-induced AP mouse model and taurocholate-induced pancreatic acinar cell line injury model. We found that polyI:C triggers type I interferon (IFN) production and downstream IFN-α/β receptor (IFNAR)-dependent signaling, which play key roles in protecting the pancreas from inflammatory injury. Knockout of IFN-β and IFNAR in mice abolished the preventive effects of polyI:C on caerulein-induced AP symptoms, which include pancreatic edema, neutrophil infiltration, the accumulation of reactive oxygen species (ROS), and inflammatory gene expression. Treating pancreatic acinar 266-6 cells with an IFNAR inhibitor, which blocks the interaction between type I IFN and IFNAR, diminishes the downregulation of oxidative stress by polyI:C. Additionally, a subsequent transcriptome analysis on the role of polyI:C in treating pancreatitis suggested that chemotaxis of neutrophils and the production of ROS were inhibited by polyI:C in the pancreases damaged by caerulein injection. Thus, polyI:C may act as a type I IFN inducer to alleviate AP, and it has the potential to be a promising therapeutic agent used at the early stages of AP

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Can p,p ‘-Dimercaptoazobisbenzene Be Produced from p-Aminothiophenol by Surface Photochemistry Reaction in the Junctions of a Ag Nanoparticle-Molecule-Ag (or Au) Film?

In this study, we attempt to experimentally address the question of whether p,p'-dimercaptoazobisbenzene (DMAB) can be produced from p-aminothiophenol (PATP) by surface photochemistry reaction in the junctions of a Ag nanoparticle-molecule-Ag (or Au) film. First, utilizing surface-enhanced Raman scattering (SERS) spectra, we provide experimental and theoretical evidence that DMAB can be produced from PATP by surface photochemistry reaction in the junctions of a Ag nanoparticle-molecule-Ag film. Second, we investigate the SERS spectra utilizing both experimental and theoretical approaches, ultimately revealing that DMAB cannot be produced from PATP in the junctions of a Ag nanoparticle-molecule-Au film. The electromagnetic enhancements are estimated with three-dimensional finite-difference time domain methods, which are about 9 x 10(5) times in the junctions of Ag nanoparticle-PATP-Ag/Au films

HIV-1 Reactivation Induced by the Periodontal Pathogens Fusobacterium nucleatum and Porphyromonas gingivalis Involves Toll-Like Receptor 4 and 9 Activation in Monocytes/Macrophages▿

Although oral coinfections (e.g., periodontal disease) are highly prevalent in human immunodeficiency virus type 1-positive (HIV-1+) patients and appear to positively correlate with viral load levels, the potential for oral bacteria to induce HIV-1 reactivation in latently infected cells has received little attention. We showed that HIV-1 long terminal repeat (LTR) promoter activation can be induced by periodontopathogens in monocytes/macrophages; nevertheless, the mechanisms involved in this response remain undetermined. Since Toll-like receptor 2 (TLR2), TLR4, and TLR9 activation have been involved in HIV-1 recrudescence, we sought to determine the role of these TLRs in HIV-1 reactivation induced by the periodontal pathogens Fusobacterium nucleatum and Porphyromonas gingivalis using BF24 monocytes/macrophages stably transfected with the HIV-1 promoter driving chloramphenicol acetyltransferase (CAT) expression and THP89GFP cells, a model of HIV-1 latency. We demonstrated that TLR9 activation by F. nucleatum and TLR2 activation by both bacteria appear to be involved in HIV-1 reactivation; however, TLR4 activation had no effect. Moreover, the autocrine activity of tumor necrosis factor alpha (TNF-α) but not interleukin-1β (IL-1β) produced in response to bacteria could impact viral reactivation. The transcription factors NF-κB and Sp1 appear to be positively regulating HIV-1 reactivation induced by these oral pathogens. These results suggest that oral Gram-negative bacteria (F. nucleatum and P. gingivalis) associated with oral and systemic chronic inflammatory disorders enhance HIV-1 reactivation in monocytes/macrophages through TLR2 and TLR9 activation in a mechanism that appears to be transcriptionally regulated. Increased bacterial growth and emergence of these bacteria or their products accompanying chronic oral inflammatory diseases could be risk modifiers for viral replication, systemic immune activation, and AIDS progression in HIV-1+ patients

HIV-1 Reactivation Induced by the Periodontal Pathogens Fusobacterium nucleatum and Porphyromonas gingivalis Involves Toll-Like Receptor 2 and 9 Activation in Monocytes/Macrophages

Although oral coinfections (e.g., periodontal disease) are highly prevalent in human immunodeficiency virus type 1-positive (HIV-1+) patients and appear to positively correlate with viral load levels, the potential for oral bacteria to induce HIV-1 reactivation in latently infected cells has received little attention. We showed that HIV-1 long terminal repeat (LTR) promoter activation can be induced by periodontopathogens in monocytes/macrophages; nevertheless, the mechanisms involved in this response remain undetermined. Since Toll-like receptor 2 (TLR2), TLR4, and TLR9 activation have been involved in HIV-1 recrudescence, we sought to determine the role of these TLRs in HIV-1 reactivation induced by the periodontal pathogens Fusobacterium nucleatum and Porphyromonas gingivalis using BF24 monocytes/macrophages stably transfected with the HIV-1 promoter driving chloramphenicol acetyltransferase (CAT) expression and THP89GFP cells, a model of HIV-1 latency. We demonstrated that TLR9 activation by F. nucleatum and TLR2 activation by both bacteria appear to be involved in HIV-1 reactivation; however, TLR4 activation had no effect. Moreover, the autocrine activity of tumor necrosis factor alpha (TNF-alpha) but not interleukin-1β (IL-1β) produced in response to bacteria could impact viral reactivation. The transcription factors NF-κB and Sp1 appear to be positively regulating HIV-1 reactivation induced by these oral pathogens. These results suggest that oral Gram-negative bacteria (F. nucleatum and P. gingivalis) associated with oral and systemic chronic inflammatory disorders enhance HIV-1 reactivation in monocytes/macrophages through TLR2 and TLR9 activation in a mechanism that appears to be transcriptionally regulated. Increased bacterial growth and emergence of these bacteria or their products accompanying chronic oral inflammatory diseases could be risk modifiers for viral replication, systemic immune activation, and AIDS progression in HIV-1+ patients