Host Tissue Damage Research Articles

Intravenous Injection of Muse Cells as a Potential Therapeutic Approach for Epidermolysis Bullosa

Intravenous Injection of Muse Cells as a Potential Therapeutic Approach for Epidermolysis Bullosa

Additional characterization of the adult worm Mammomonogamus laryngeus (Railliet, 1899) and the tissue lesions caused by the infection in buffaloes

Mammomonogamus spp. are parasites with curious characteristics, such as the “Y” shape that results from male and female maintaining the permanent copulation position and the controversial presence or absence of spicules. These nematodes are hematophagous and cause damage to the upper respiratory tracts of cattle, sheep, goats, deer, wild yaks, and orangutans. Human infection is rare and most cases until now have been in the Caribbean Islands or in Brazil, and mainly in farmworkers but recently there have been reports affecting tourists. In the present work, the parasites were recovered from the laryngopharynx and larynx region of Bubalus bubalis on the island of Marajó, Pará, Brazil. Different microscopy methodologies were applied (bright field, fluorescence, and scanning electron microscopy) to explore the ultrastructural details of the anterior end, genital structures and the host tissue damage caused by the nematodes. The well-developed mouth is an important structure in the identification of these nematodes and used by the parasite to adhere to the host’s tissue. Different methodologies in microscopy and molecular biology contributed to a detailed morphological description and showed the phenotypic position of Mammomonogamus laryngeus. Light and scanning electron microscopy (SEM) showed details of the papillae, amphids, festoons, ribs, and teeth. Fluorescence microscopy enabled a detailed characterization of different structures, such as the bursal rays and SEM enabled the visualization of the specialized features of the cuticle surface in the male and female. Histopathological analyses, cryofracture and environmental SEM experiments of the infected tissues were carried out in order to investigate the lesions resultant from the parasitism. In addition, the parasite couples were submitted to cryofracture and these results revealed details of the reproductive structures of both sexes, including the male spicule.

Discovery of a novel indole pharmacophore for the irreversible inhibition of myeloperoxidase (MPO)

Myeloperoxidase (MPO) activity and subsequent generation of hypochlorous acid has been associated with the killing of host-invading microorganisms (e.g. bacteria, viruses, and fungi). However, during oxidative stress, high MPO activity can damage host tissue and is linked to several chronic inflammatory conditions. Herein, we describe the development of a novel biaryl, indole-pyrazole series of irreversible mechanism-based inhibitors of MPO. Derived from an indole-containing high-throughput screen hit, optimization efforts resulted in potent and selective 6-substituted indoles with good oral bioavailability and in vivo activity.

The role of TCF-1 in graft-versus-host disease and antitumor effects

Abstract Allogeneic hematopoietic stem cell transplants (HSCT) are used as a curative therapy for malignancies such as cancer. Residual tumor cells and recurrence are controlled by the graft-versus-tumor (GVT) effect, mediated by alloreactive T cells. However, these same cells also cause graft-versus-host disease (GVHD), a serious side effect. Naïve mature T cells in the graft recognize foreign HLA molecules on the host’s cells, and are alloactivated. The T cells then proliferate, produce cytokines, and migrate to the GVHD target organs (liver, skin, and small intestine), damaging host tissues. Separation of detrimental GVHD from beneficial GVT remains a serious unaddressed problem. Thus, the goal of this project is to achieve this separation through T cell signaling modulation. The transcription factors T-bet and Eomes impact GVHD and GVT. They are downstream of T Cell Factor-1 (TCF-1), which is important in thymocytes and T cell activation. To determine the role of TCF-1 in alloactivation, mice with T cell-specific deletion of TCF-1 were phenotyped. These mice had increased expression of Eomes, Tbet, CD8+ central memory T cells, and polarization of CD44 expression. They also showed reduced activating T cells, and reduced expression of CXCR5 (a major chemokine receptor) when alloactivated. Finally, GVHD severity was reduced in mice transplanted with TCF-1-deficient T cells, and survival was improved in these mice. These data suggest that loss of TCF-1 results in a more activated state, yet GVHD is still reduced. Therefore, these cells may still be capable of antitumor immunity, separating GVHD from GVT. This work will help to improve outcomes for HSCT patients and enhance understanding of how mature alloactivated T cells are regulated.

Supramolecular Assemblies of Heterogeneous Mesoporous Silica Nanoparticles to Co-deliver Antimicrobial Peptides and Antibiotics for Synergistic Eradication of Pathogenic Biofilms.

Pathogenic biofilms protected by extracellular polymeric substances frequently compromise the efficiency of antibacterial drugs and severely threaten human health. In this study, we designed a multi-stimuli-responsive magnetic supramolecular nanoplatform to co-deliver large and low molecular weight drugs for synergistic eradication of pathogenic biofilms. This co-delivery platform was composed of mesoporous silica nanoparticles (MSNs) with large pores (MSNLP) capped by β-cyclodextrin (β-CD)-modified polyethylenimine (PEICD) and adamantane (ADA)-decorated MSNs containing a magnetic core (MagNP@MSNA) capped by cucurbit[6]uril (CB[6]). The host MSNs (H, MSNLP@PEICD) and the guest MSNs (G, MagNP@MSNA-CB[6]) spontaneously form coassemblies (H+G), based on the host-guest interactions between β-CD and ADA. Under the stimulus of pathogen cells together with heating by an alternating magnetic field (AMF), the supramolecular coassemblies released both the large molecular weight antimicrobial peptide melittin (MEL) and the low molecular weight antibiotic ofloxacin (OFL) with high efficiency. As compared to free drugs (MEL and OFL) or unattached MSNs (H or G), the drug-loading H+G coassemblies (H-MEL+G-OFL) exhibited much higher capacity for biofilm eradication, thoroughly removing biofilm biomass and killing the pathogenic cells, and displaying no obvious toxicity to mammalian cells. This strong antibiofilm capacity was severely decreased when the host and guest components were prevented from coassembling but administered simultaneously, revealing the critical role of the supramolecular assembly in biofilm removal. Moreover, an in vivo implantation model showed that the coassemblies eradicated the pathogenic biofilms from the implants, preventing host tissue damage and inflammation. Therefore, the co-delivering and multi-stimuli-responsive nanocarriers could overcome the anti-infection difficulties during treatment of infections because of protective biofilms.

OmpA Porin of Salmonella enterica serovar Enteritidis Possesses Aamyloid‐Forming Properties

The major focus of Salmonella enterica studies is the molecular determinants of the virulence and host‐specificity. Important virulence factors shared by the majority of pathogenic gram‐negative bacteria are the outer membrane proteins (OMP), many of which belong to the porins – beta barrel proteins serving as passive membrane pores. One of the most studied in terms of pathogenesis is the OmpA porin family. The proteins of the OmpA family are involved in the important virulence‐ and pathogenesis‐related processes including adhesion, penetration and damage of host tissues, as well as avoiding the immune response. Proteins of this family are highly conserved. For instance, the amino acid sequence similarity of OmpA proteins of Escherichia coli and S. enterica serovar Enteritidis is 94%. Considering ability of the E. coli OmpA porin to form amyloid‐like aggregates, we have produced recombinant OmpA protein from S. enterica serovar Enteritidis in vitro and have analyzed its amyloid properties. We have determined the typical fibrillary morphology of the obtained OmpA aggregates using transmission electron microscopy and have demonstrated that these aggregates exhibit yellow‐green birefringence being stained with amyloid‐specific dye Congo Red. We have also found that OmpA protein fused with YFP aggregates in yeast Saccharomyces cerevisiae while OmpA fibrils secreted in vivo at the surface of bacterial cells in the Curli‐Dependent Amyloid Generator system demonstrate properties typical for amyloids including unbranched morphology and birefringence upon binding with Congo Red. Taken together, these results suggest that the S. enterica serovar Enteritidis OmpA porin has amyloid‐forming properties.Support or Funding InformationThis work was supported by the Russian Science Foundation (Grant No 19‐76‐00026).

Analysis of influenza virus-induced perturbation in autophagic flux and its modulation during Vitamin D3 mediated anti-apoptotic signaling

Vitamin D3/Calcitriol supplementation in humans is associated with reduced incidence and severity during influenza A virus (IAV) infection. Apoptosis in response to IAV infection is a major contributor to host cell death and tissue damage; however, its modulation by Vitamin D3 remains unclear. In this study, we demonstrate the efficacy of Vitamin D3 in preventing apoptosis induction by pandemic influenza A (H1N1)pdm09 virus in human alveolar cells (A549). Human alveolar epithelial cell line A549 was used to assess the cytotoxic effects of IAV infection. Immunoblotting and fluorescence microscopy were used to study apoptosis and autophagy. The results of the present study demonstrate that IAV induces apoptosis by subversion of host autophagy via down-regulating components of autophagic machinery involved in autophagosome-lysosome fusion and lysosomal activity. Vitamin D3 restores the autophagic flux inhibited by IAV by upregulating the expression of Syntaxin-17 (STX17) and V-type proton ATPase subunit (ATP6V0A2) thereby causing a concomitant decrease in cellular apoptosis via a Vitamin D3 receptor (VDR) dependent mechanism. The present study suggests that Vitamin D3 is a potentially useful agent for limiting IAV-induced cellular injury via its pro-autophagic action.

Infections With Extracellular Trypanosomes Require Control by Efficient Innate Immune Mechanisms and Can Result in the Destruction of the Mammalian Humoral Immune System.

Salivarian trypanosomes are extracellular parasites that affect humans, livestock, and game animals around the world. Through co-evolution with the mammalian immune system, trypanosomes have developed defense mechanisms that allow them to thrive in blood, lymphoid vessels, and tissue environments such as the brain, the fat tissue, and testes. Trypanosomes have developed ways to circumvent antibody-mediated killing and block the activation of the lytic arm of the complement pathway. Hence, this makes the innate immune control of the infection a crucial part of the host-parasite interaction, determining infection susceptibility, and parasitemia control. Indeed, trypanosomes use a combination of several independent mechanisms to avoid clearance by the humoral immune system. First, perpetuated antigenic variation of the surface coat allows to escape antibody-mediated elimination. Secondly, when antibodies bind to the coat, they are efficiently transported toward the endocytosis pathway, where they are removed from the coat proteins. Finally, trypanosomes engage in the active destruction of the mammalian humoral immune response. This provides them with a rescue solution in case antigenic variation does not confer total immunological invisibility. Both antigenic variation and B cell destruction pose significant hurdles for the development of anti-trypanosome vaccine strategies. However, developing total immune escape capacity and unlimited growth capabilities within a mammalian host is not beneficial for any parasite, as it will result in the accelerated death of the host itself. Hence, trypanosomes have acquired a system of quorum sensing that results in density-dependent population growth arrest in order to prevent overpopulating the host. The same system could possibly sense the infection-associated host tissue damage resulting from inflammatory innate immune responses, in which case the quorum sensing serves to prevent excessive immunopathology and as such also promotes host survival. In order to put these concepts together, this review summarizes current knowledge on the interaction between trypanosomes and the mammalian innate immune system, the mechanisms involved in population growth regulation, antigenic variation and the immuno-destructive effect of trypanosomes on the humoral immune system. Vaccine trials and a discussion on the role of innate immune modulation in these trials are discussed at the end.

The Role of Myeloperoxidase in Biomolecule Modification, Chronic Inflammation, and Disease.

Significance: The release of myeloperoxidase (MPO) by activated leukocytes is critical in innate immune responses. MPO produces hypochlorous acid (HOCl) and other strong oxidants, which kill bacteria and other invading pathogens. However, MPO also drives the development of numerous chronic inflammatory pathologies, including atherosclerosis, neurodegenerative disease, lung disease, arthritis, cancer, and kidney disease, which are globally responsible for significant patient mortality and morbidity. Recent Advances: The development of imaging approaches to precisely identify the localization of MPO and the molecular targets of HOCl in vivo is an important advance, as typically the involvement of MPO in inflammatory disease has been inferred by its presence, together with the detection of biomarkers of HOCl, in biological fluids or diseased tissues. This will provide valuable information in regard to the cell types responsible for releasing MPO in vivo, together with new insight into potential therapeutic opportunities. Critical Issues: Although there is little doubt as to the value of MPO inhibition as a protective strategy to mitigate tissue damage during chronic inflammation in experimental models, the impact of long-term inhibition of MPO as a therapeutic strategy for human disease remains uncertain, in light of the potential effects on innate immunity. Future Directions: The development of more targeted MPO inhibitors or a treatment regimen designed to reduce MPO-associated host tissue damage without compromising pathogen killing by the innate immune system is therefore an important future direction. Similarly, a partial MPO inhibition strategy may be sufficient to maintain adequate bacterial activity while decreasing the propagation of inflammatory pathologies.

Fc-modified HIT-like monoclonal antibody as a novel treatment for sepsis

AbstractSepsis is characterized by multiorgan system dysfunction that occurs because of infection. It is associated with high morbidity and mortality and is in need of improved therapeutic interventions. Neutrophils play a crucial role in sepsis, releasing neutrophil extracellular traps (NETs) composed of DNA complexed with histones and toxic antimicrobial proteins that ensnare pathogens, but also damage host tissues. At presentation, patients often have a significant NET burden contributing to the multiorgan damage. Therefore, interventions that inhibit NET release would likely be ineffective at preventing NET-based injury. Treatments that enhance NET degradation may liberate captured bacteria and toxic NET degradation products (NDPs) and likely be of limited therapeutic benefit as well. We propose that interventions that stabilize NETs and sequester NDPs may be protective in sepsis. We showed that platelet factor 4 (PF4), a platelet-associated chemokine, binds and compacts NETs, increasing their resistance to DNase I. We now show that PF4 increases NET-mediated bacterial capture, reduces the release of NDPs, and improves outcome in murine models of sepsis. A monoclonal antibody KKO which binds to PF4-NET complexes, further enhances DNase resistance. However, the Fc portion of this antibody activates the immune response and increases thrombotic risk, negating any protective effects in sepsis. Therefore, we developed an Fc-modified KKO that does not induce these negative outcomes. Treatment with this antibody augmented the effects of PF4, decreasing NDP release and bacterial dissemination and increasing survival in murine sepsis models, supporting a novel NET-targeting approach to improve outcomes in sepsis.

Volatile Anesthetic Sevoflurane Attenuates Toll-Like Receptor 1/2 Activation.

Although immunomodulatory effects of anesthetics have been increasingly recognized, their underlying molecular mechanisms are not completely understood. Toll-like receptors (TLRs) are one of the major receptors to recognize invading pathogens and danger signals from damaged host tissues to initiate immune responses. Among the TLR family, TLR2 and TLR4 recognize a wide range of ligands and are considered to be important players in perioperative pathophysiology. Based on our recent finding that volatile anesthetics modulate TLR4 function, we tested our hypothesis that they would also modulate TLR2 function. The effect of anesthetics isoflurane, sevoflurane, propofol, and dexmedetomidine on TLR2 activation was examined by reporter assays. An anesthetic that affected the activation was subjected to in silico rigid docking simulation on TLR2. To test our prediction that sevoflurane and a TLR1/TLR2 ligand Pam3CSK4 would compete for the same pocket of TLR2, we performed Pam3CSK4 competitive binding assay to TLR2 using HEK cells stably transfected with TLR2 (HEK-TLR2) with or without sevoflurane. We examined the effect of different anesthetics on the functions of human neutrophils stimulated with TLR2 ligands. Kruskal-Wallis test and Mann-Whitney U test were used for statistical analysis. We observed that the attenuation of TLR1/TLR2 activation was seen on sevoflurane exposure but not on isoflurane, propofol, or dexmedetomidine exposure. The attenuation of TLR2/TLR6 activation was not seen in any of the anesthetics tested. The rigid docking simulation predicted that sevoflurane and Pam3CSK4 bound to the same pocket of TLR1/TLR2 complex. The binding of Pam3CSK4 to HEK-TLR2 cells was impaired in the presence of sevoflurane, indicating that sevoflurane and Pam3CSK4 competed for the pocket, as predicted in silico. The stimulation of neutrophils with Pam3CSK4 induced L-selection shedding but did not affect phagocytosis and reactive oxygen species production. L-selectin shedding from neutrophils was attenuated only by sevoflurane, consistent with the result of our reporter assays. We found that TLR1/TLR2 activation was attenuated by sevoflurane, but we found no evidence for attenuation by isoflurane, propofol, or dexmedetomidine at clinically relevant concentrations. Our structural analysis and competition assay supported that sevoflurane directly bound to TLR2 at the interphase of the TLR1/TLR2 complex. Sevoflurane attenuated neutrophil L-selectin shedding, an important step for neutrophil migration.

The Inflammasome and Type-2 Immunity in Clostridium difficile Infection.

Clostridium difficile (reclassified as " Clostridioides ") is the leading cause of hospital-acquired infections in the United States, and is associated with high-patient mortality and high rates of recurrence. Inflammasome priming and activation by the bacterial toxins, TcdA , TcdB , and C. difficile transferase (CDT), initiates a potent immune response that is characterized by interleukin- (IL) 8, IL-1β, and neutrophil recruitment, and is required for pathogen killing. However, it is becoming clearer that a strong inflammatory response during C. difficile infection can result in host tissue damage, and is associated with worse patient outcome. Recent work has begun to show that a type-2 immune response, most often associated with helminth infections, allergy, and asthma, may be protective during C. difficile infection. While the mechanisms through how this response protect are still unclear, there is evidence that it is mediated through eosinophil activity. This chapter will review the immune response to C. difficile, how the inflammasome signaling during infection can deleterious to the host, as well as the current understanding of a protective type-2 immunity. Understanding the host immune response may help to provide insight into novel approaches to prognosis markers, as well as how treat patient C. difficile infection without, or in addition to, antibiotics.

Glutathione catabolism by Treponema denticola impacts its pathogenic potential

Treponema denticola is a spirochete that is etiologic for periodontal diseases. This bacterium is one of two periodontal pathogens that have been shown to have a complete three step enzymatic pathway (GTSP) that catabolizes glutathione to H2S. This pathway may contribute to the tissue pathology seen in periodontitis since diseased periodontal pockets have lower glutathione levels than healthy sites with a concomitant increase in H2S concentration. In order to be able to demonstrate that glutathione catabolism by the GTSP is critical for the pathogenic potential of T. denticola, allelic replacement mutagenesis was used to make a deletion mutant (Δggt) in the gene encoding the first enzyme in the GTSP. The mutant cannot produce H2S from glutathione since it lacks gamma-glutamyltransferase (GGT) activity. The hemolytic and hemoxidation activities of wild type T. denticola plus glutathione are reduced to background levels with the Δggt mutant and the mutant has lost the ability to grow aerobically when incubated with glutathione. The Δggt bacteria with glutathione cause less cell death in human gingival fibroblasts (hGFs) in vitro than do wild type T. denticola and the levels of hGF death correlate with the amounts of H2S produced. Importantly, the mutant spirochetes plus glutathione make significantly smaller lesions than wild type bacteria plus glutathione in a mouse back lesion model that assesses soft tissue destruction, a major symptom of periodontal diseases. Our results are the first to prove that T. denticola thiol-compound catabolism by its gamma-glutamyltransferase can play a significant role in the in the types of host tissue damage seen in periodontitis.

Therapeutic Myeloperoxidase Inhibition Attenuates Neutrophil Activation, ANCA-Mediated Endothelial Damage, and Crescentic GN.

Myeloperoxidase released after neutrophil and monocyte activation can generate reactive oxygen species, leading to host tissue damage. Extracellular glomerular myeloperoxidase deposition, seen in ANCA-associated vasculitis, may enhance crescentic GN through antigen-specific T and B cell activation. Myeloperoxidase-deficient animals have attenuated GN early on, but augmented T cell responses. We investigated the effect of myeloperoxidase inhibition, using the myeloperoxidase inhibitor AZM198, to understand its potential role in treating crescentic GN. We evaluated renal biopsy samples from patients with various forms of crescentic GN for myeloperoxidase and neutrophils, measured serum myeloperoxidase concentration in patients with ANCA-associated vasculitis and controls, and assessed neutrophil extracellular trap formation, reactive oxygen species production, and neutrophil degranulation in ANCA-stimulated neutrophils in the absence and presence of AZM198. We also tested the effect of AZM198 on ANCA-stimulated neutrophil-mediated endothelial cell damage in vitro, as well as on crescentic GN severity and antigen-specific T cell reactivity in the murine model of nephrotoxic nephritis. All biopsy specimens with crescentic GN had extracellular glomerular myeloperoxidase deposition that correlated significantly with eGFR and crescent formation. In vitro, AZM198 led to a significant reduction in neutrophil extracellular trap formation, reactive oxygen species production, and released human neutrophil peptide levels, and attenuated neutrophil-mediated endothelial cell damage. In vivo, delayed AZM198 treatment significantly reduced proteinuria, glomerular thrombosis, serum creatinine, and glomerular macrophage infiltration, without increasing adaptive T cell responses. Myeloperoxidase inhibition reduced neutrophil degranulation and neutrophil-mediated endothelial cell damage in patients with ANCA-associated vasculitis. In preclinical crescentic GN, delayed myeloperoxidase inhibition suppressed kidney damage without augmenting adaptive immune responses, suggesting it might offer a novel adjunctive therapeutic approach in crescentic GN.

A nanoparticle-functionalized wound dressing device for toxin neutralization

Pore-forming toxins (PFTs) that attack host cells have shown to perform an essential role in bacterial infections. Neutralization of these toxins has become an attractive approach to promote the recovery of damaged host tissues. In this study, we propose an interconnected macroporous hydrogel containing polydiacetylene (PDA) nanoparticles to efficiently sense and bind PFTs. The PDA nanoparticles are fabricated through a self-assembly process and then mixed into the gelatin monomer solution for polymerization. Using cryogelation technology, we can obtain the nanoparticle-functionalized hydrogels with controlled interconnected pores and well-defined properties. Meanwhile, the obtained hydrogels with favorable biocompatibility show the capability of retaining the nanoparticles over a long time and efficiently binding the PFTs. In addition, the functional hydrogels with different pores present distinctive detoxification abilities. Overall, this work introduces a promising detoxification device that incorporates functional nanoparticles into the macroporous hydrogel and could be used as a wound dressing for local treatment of bacterial infections in the future.

EKSPRESI Interleukin-1 (IL-1) PADA PERIAPIKAL AKIBAT INDUKSI BAKTERI Enterococcus faecalis

Background. Root canal treatment is a main role in decreasing infection from root canal and pulp. The main cause of periapical damage mostly are bacteries. E.faecalis is a bactery that is found as an etiology of endodontic treatment failure. Cell wall of this bacteria is containing Lipoteichoic acid (LTA). LTA can penetrate into the periradicular tissue, act as endotoxin in host and cause periradicular inflammation and destruction. It occurs due to the capability of IL-1. IL-1 is the proinflammation cytokine that is the key of host response bacteria invation and tissue damage. Also IL-1 could cause some indirectly tissue damage through the activation of MMPS. MMPs to stop the collagen formation. Purpose. The aim of this study is to know about the expression of IL- 1 during the periapical tissue damage due to induction of E.faecalis. Method. This study used laboratory experimental with the post test only control group design. A total of 54 male rats were randomly divided into 2 main groups, which each main group had 3 subgroups. Group A (control) : every tooth was induced only by sterile BHIb. Group A had 3 subgroups (A Control day 3, 10, and 21), group B : every tooth was induced by 10 μl BHI-b E.faecalis ATCC212(106 CFU), it was contained 3 sub groups (B day 3,10, and 21). The animals were sacrificed based on their days scheduled group and prepared for histological examination of tissue damage, then we did the immunohistochemistry followed by calculation on the light microscope. Result. The analysis revealed that the expression of IL-1 increased significantly in group B when E.faecalis was induced. Conclusion. From this study we know that the expression of IL-1 is increasing during the periapical tissue damage that induced by E.faecalis.

Human ectoenzyme-expressing ILC3: immunosuppressive innate cells that are depleted in graft-versus-host disease

AbstractAllogeneic hematopoietic stem cell transplantation (allo-HSCT) is often associated with chemotherapy- and radiotherapy-induced host tissue damage, leading to graft-versus-host disease (GVHD). Innate lymphoid cells (ILC) have an essential role in tissue homeostasis and tissue repair via their production of interleukin (IL)-22, which acts on intestinal stem cells. The tissue healing capacities of ILC via IL-22 in the context of allo-HSCT and GVHD has previously been demonstrated in a mouse model for acute GVHD. We investigated potential other ways of ILC-mediated tissue protection against GVHD. Tissue injury leads to the release of danger-associated molecular patterns (DAMPs). DAMPs interact with purinergic receptors and ectoenzymes on immune cells and induce pleiotropic effects, including activation of proinflammatory antigen-presenting cells and immunosuppressive effects via the generation of adenosine. Here, we report a novel subset of human ILC3 that coexpress the ectoenzymes CD39 and CD73 (ecto+ ILC3). Ecto+ ILC3 express RORγt and were present in the oral-gastrointestinal tract and bone marrow. ILC3 ectoenzyme expression is modulated by the proinflammatory cytokine IL-1β. Extracellular adenosine triphosphate (eATP) stimulated ecto+ ILC3 to produce IL-22 and adenosine. Activated ecto+ ILC3 suppressed autologous T-cell proliferation in coculture experiments via the production of adenosine. In allo-HSCT recipients, intestinal GVHD was associated with reduced proportions of ecto+ ILC3 and decreased levels of adenosine and its metabolite inosine. Taken together, ecto+ ILC3 have immunosuppressive properties, but in patients with GVHD, ecto+ ILC3 are depleted. A lack of ecto+ ILC3 and subsequent reduced capacity to neutralize DAMPs may contribute to the development of GVHD.

Neutrophils in community-acquired pneumonia: parallels in dysfunction at the extremes of age

"Science means constantly walking a tight rope" Heinrich Rohrer, physicist, 1933. Community-acquired pneumonia (CAP) is the leading cause of death from infectious disease worldwide and disproportionately affects older adults and...

Targeting Parasite-Produced Macrophage Migration Inhibitory Factor as an Antivirulence Strategy With Antibiotic-Antibody Combination to Reduce Tissue Damage.

Targeting virulence factors represents a promising alternative approach to antimicrobial therapy, through the inhibition of pathogenic pathways that result in host tissue damage. Yet, virulence inhibition remains an understudied area in parasitology. Several medically important protozoan parasites such as Plasmodium, Entamoeba, Toxoplasma, and Leishmania secrete an inflammatory macrophage migration inhibitory factor (MIF) cytokine homolog, a virulence factor linked to severe disease. The aim of this study was to investigate the effectiveness of targeting parasite-produced MIF as combination therapy with standard antibiotics to reduce disease severity. Here, we used Entamoeba histolytica as the model MIF-secreting protozoan, and a mouse model that mirrors severe human infection. We found that intestinal inflammation and tissue damage were significantly reduced in mice treated with metronidazole when combined with anti–E. histolytica MIF antibodies, compared to metronidazole alone. Thus, this preclinical study provides proof-of-concept that combining antiparasite MIF-blocking antibodies with current standard-of-care antibiotics might improve outcomes in severe protozoan infections.

Screening of FDA approved drugs for finding potential inhibitors against Granzyme B as a potent drug-repurposing target

Granzyme B is one of the best-characterized and extensively studied member of cytotoxic lymphocytes (CL) proteases. Initially, it is thought to be involved in eliminating virally infected or cancerous cells by using a specialized mechanism through which they are internalized into target cells. In the last decade, however this dimension has changed as there are several reports show that not only CL but also other immune cells can also synthesize Granzyme B. This leads to the possibility of the presence of these proteases in extracellular environment. Being active protease, it then raises the possibility of damaging host tissues as evident from the available reported literature. In many instances, Granzyme B is directly involved in pathogenicity, however in others, it contributes to the disease severity as their over expression makes the clinical situation quite worse which ultimately leads to the chronic state of the disease. Serine protease inhibitor-9 is a natural known intracellular inhibitor of Granzyme B, however there is less data available about the potential inhibitors that can regulate its activity in an extracellular environment. Current study is an effort to identify potential novel inhibitors of Granzyme B. For this aim, drug repurposing study was performed. Around 7900 FDA approved drugs were screened using both ligand- and target-driven approaches. Initially, all molecules were docked using induced fit docking (IFD) approach and selected 318 high-docking scored molecules were used in short (1-ns) molecular dynamics (MD) simulations. Based on MM/GBSA binding free energy calculations, 6 compounds were selected and used in long (100-ns) MD simulations. These compounds were then used in binary QSAR analysis. Therapeutic activity potentials of studied compounds were investigated by Clarivate Analytics’s MetaCore/MetaDrug platform which uses binary QSAR models. It is developed based on manually curated database of molecular interactions, molecular pathways, gene-disease associations, chemical metabolism and toxicity information. Results of selected compounds were compared with a positive control molecule. Current drug repurposing study is a step ahead in finding potential lead compounds by screening database of FDA approved molecules. We have identified novel inhibitors (Tannic acid, Mupirocin, Phytonadiol sodium diphosphate, Cefpiramide, Xenazoic acid) that have potential to decrease the activity of Granzyme B.