A Novel Encochleated Formulation Improves Atovaquone Activity in a Murine Model of Pneumocystis Pneumonia.
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ABSTRACT:
SUBMITTER: Cushion MT
PROVIDER: S-EPMC8280485 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Apoptosis of lymphocytes is important in the termination of an immune response to infection but has also been shown to have detrimental effects in animal models of systemic infection and sepsis. We sought to characterize lymphocyte apoptosis in an animal model of pneumonia due to Pneumocystis murina, an infection localized to the lungs.Control mice and mice depleted of CD4+ lymphocytes were inoculated with Pneumocystis. Apoptosis of lung and spleen lymphocytes was assayed by flow cytometry and PCR assay of apoptotic proteins.In control mice, apoptosis of lung lymphocytes was maximal just after the infection was cleared from lung tissue and then declined. However, in CD4-depleted mice, apoptosis was also upregulated in recruited lymphocytes in spite of progressive infection. In splenic lymphocytes, apoptosis was observed early at 1 week after inoculation and then declined. Apoptosis of lung lymphocytes in control mice was associated with a decrease in mRNA for Bcl-2 and an increase in mRNA for Bim. In CD4-depleted mice, lavaged CD8+ cells did change intracellular Bcl-2 but showed increased mRNA for Bim.Apoptosis of both pulmonary and extrapulmonary lymphocytes is part of the normal host response to Pneumocystis but is also triggered in CD4-deficient animals with progressive infection. In normal mice apoptosis of pulmonary lymphocytes may serve to terminate the immune response in lung tissue. Apoptosis of lung lymphocytes takes place via both the intrinsic and extrinsic apoptotic pathways and is associated with changes in both pro- and anti-apoptotic proteins.
| S-EPMC2714500 | biostudies-literature
Project description:Little is known about the role of the cytokine interleukin-12 (IL-12) in Pneumocystis pneumonia or its potential use as immunotherapy. We asked whether release of IL-12 is part of the normal host response to this infection and whether local treatment with IL-12 or gene transfer of IL-12 could accelerate clearance of infection. IL-12 was assayed by enzyme-linked immunosorbent assay in normal mice and in mice deficient in IL-12 after inoculation of Pneumocystis carinii. P. carinii-infected mice were treated with local instillation of IL-12 and gene transfer of the IL-12 gene. Inoculation of P. carinii into normal mice evoked a brisk release of IL-12 into lung tissue, and IL-12 P35-deficient mice showed delayed clearance of infection measured by PCR for P. carinii rRNA. In control mice, intranasal recombinant IL-12 accelerated clearance of infection, and this was associated with increased recruitment of inflammatory cells into lavage fluid and increased release of tumor necrosis factor alpha, IL-12, and gamma interferon. Similar results were observed in infected mice depleted of CD4+ lymphocytes by using in vivo transfer of the IL-12 gene in a replication-deficient adenoviral vector. IL-12 is part of the normal host response to infection with P. carinii. IL-12 therapy can enhance host resistance to infection in both normal mice and mice depleted of CD4+ T lymphocytes. A treatment effect of IL-12 is mediated through enhanced inflammatory cell recruitment into lung tissue and increased tissue concentrations of proinflammatory cytokines.
| S-EPMC2346719 | biostudies-literature
Project description:CD4(+) T cells play a key role in host defense against Pneumocystis infection. To define the role of naïve CD4(+) T cell production through the thymopoietic response in host defense against Pneumocystis infection, Pneumocystis murina infection in the lung was induced in adult male C57BL/6 mice with and without prior thymectomy. Pneumocystis infection caused a significant increase in the number of CCR9(+) multipotent progenitor (MPP) cells in the bone marrow and peripheral circulation, an increase in populations of earliest thymic progenitors (ETPs) and double negative (DN) thymocytes in the thymus, and recruitment of naïve and total CD4(+) T cells into the alveolar space. The level of murine signal joint T cell receptor excision circles (msjTRECs) in spleen CD4(+) cells was increased at 5 weeks post-Pneumocystis infection. In thymectomized mice, the numbers of naïve, central memory, and total CD4(+) T cells in all tissues examined were markedly reduced following Pneumocystis infection. This deficiency of naïve and central memory CD4(+) T cells was associated with delayed pulmonary clearance of Pneumocystis. Extracts of Pneumocystis resulted in an increase in the number of CCR9(+) MPPs in the cultured bone marrow cells. Stimulation of cultured bone marrow cells with ligands to Toll-like receptor 2 ([TLR-2] zymosan) and TLR-9 (ODN M362) each caused a similar increase in CCR9(+) MPP cells via activation of the Jun N-terminal protein kinase (JNK) pathway. These results demonstrate that enhanced production of naïve CD4(+) T lymphocytes through the thymopoietic response and enhanced delivery of lymphopoietic precursors from the bone marrow play an important role in host defense against Pneumocystis infection.
| S-EPMC3088129 | biostudies-literature
Project description:Humanized NOG-EXL (huNOG-EXL) mice control P. murina infection significantly better than control NOG-EXL mice, as evidenced by markedly decrased lung fungal burdens at both 3 and 6 weeks post-infection. Human cytokine-generating CD4+ and CD8+ T cells in the lung and serum IgM antibody, which were specifically in responses to pneumocystis antigen, were detected in huNOG-EXL mice only. For humanized NOG-EXL mouse group at 6 weeks post-infection, the whole lung RNAseq analyses were performed and the data indicated that the lower lung fungal burden is associated with higher CD209 gene expression.
2020-12-24 | GSE159562 | GEO
Project description:Pneumocystis is an important opportunistic fungus that causes pneumonia in children and immunocompromised individuals. Recent genomic data show that divergence of major surface glycoproteins may confer speciation and host range selectivity. On the other hand, immune clearance between mice and humans is well correlated. Thus, we hypothesized that humanize mice may provide information about human immune responses involved in controlling Pneumocystis infection. CD34-engrafted huNOG-EXL mice controlled fungal burdens to a greater extent than nonengrafted mice. Moreover, engrafted mice generated fungal-specific IgM. Fungal control was associated with a transcriptional signature that was enriched for genes associated with nonopsonic recognition of trophs (CD209) and asci (CLEC7A). These same genes were downregulated in CD4-deficient mice as well as twins with bare lymphocyte syndrome with Pneumocystis pneumonia.
| S-EPMC7934868 | biostudies-literature
Project description:Pneumocystis pneumonia (PcP) is a significant cause of morbidity and mortality in immunocompromised patients. In humans, PcP is caused by the opportunistic fungal species Pneumocystis jirovecii. Progress in Pneumocystis research has been hampered by a lack of viable in vitro culture methods, which limits laboratory access to human-derived organisms for drug testing. Consequently, most basic drug discovery research for P. jirovecii is performed using related surrogate organisms such as Pneumocystis carinii, which is derived from immunosuppressed rodents. While these studies provide useful insights, important questions arise about interspecies variations and the relative utility of identified anti-Pneumocystis agents against human P. jirovecii. Our recent work has identified the histone acetyltransferase (HAT) Rtt109 in P. carinii (i.e., PcRtt109) as a potential therapeutic target for PcP, since Rtt109 HATs are widely conserved in fungi but are absent in humans. To further address the potential utility of this target in human disease, we now demonstrate the presence of a functional Rtt109 orthologue in the clinically relevant fungal pathogen P. jirovecii (i.e., PjRtt109). In a fashion similar to that of Pcrtt109, Pjrtt109 restores H3K56 acetylation and genotoxic resistance in rtt109-null yeast. Recombinant PjRtt109 is an active HAT in vitro, with activity comparable to that of PcRtt109 and yeast Rtt109. PjRtt109 HAT activity is also enhanced by the histone chaperone Asf1 in vitro. PjRtt109 and PcRtt109 showed similar low micromolar sensitivities to two reported small-molecule HAT inhibitors in vitro. Together, these results demonstrate that PjRtt109 is a functional Rtt109 HAT, and they support the development of anti-Pneumocystis agents directed at Rtt109-catalyzed histone acetylation as a novel therapeutic target for human PcP.
| S-EPMC4068529 | biostudies-literature
Project description:PurposeNegative surgical margins (NSMs) have favorable prognostic implications in breast tumor resection surgery. Fluorescence image-guided surgery (FIGS) has the ability to delineate surgical margins in real time, potentially improving the completeness of tumor resection. We have recently developed indocyanine green (ICG)-loaded self-assembled hyaluronic acid (HA) nanoparticles (NanoICG) for solid tumor imaging, which were shown to enhance intraoperative contrast.ProceduresThis study sought to assess the efficacy of NanoICG on completeness of breast tumor resection and post-surgical survival. BALB/c mice bearing iRFP+/luciferase+ 4T1 syngeneic breast tumors were administered NanoICG or ICG, underwent FIGS, and were compared to bright light surgery (BLS) and sham controls.ResultsNanoICG increased the number of complete resections and improved tumor-free survival. This was a product of improved intraoperative contrast enhancement and the identification of a greater number of small, occult lesions than ICG and BLS. Additionally, NanoICG identified chest wall invasion and predicted recurrence in a model of late-stage breast cancer.ConclusionsNanoICG is an efficacious intraoperative contrast agent and could potentially improve surgical outcomes in breast cancer.
| S-EPMC7280079 | biostudies-literature
Project description:Rezafungin is a novel echinocandin in Phase 3 development for prevention of invasive fungal disease caused by Candida spp., Aspergillus spp. and Pneumocystis jirovecii in blood and marrow transplantation patients. For such patients, standard antifungal prophylaxis currently comprises an azole for Candida and Aspergillus plus trimethoprim-sulfamethoxazole (TMP-SMX) for Pneumocystis pneumonia (PCP) despite drug-drug-interactions and intolerability that may limit their use, thus, alternatives are desirable. Rezafungin demonstrates a favorable safety profile and pharmacokinetic properties that allow for once-weekly dosing in addition, to antifungal activity against these predominant pathogens. Herein, the in vivo effects of rezafungin against Pneumocystis murina pneumonia were evaluated in immunosuppressed mouse models of prophylaxis and treatment using microscopy and qPCR assessments. In the prophylaxis model, immunosuppressed mice inoculated with P. murina were administered TMP-SMX (50/250 mg/kg 1×/week or 3×/week), caspofungin (5 mg/kg 3×/week), rezafungin (20 mg/kg, 1×/week or 3×/week; 5 mg/kg, 3×/week) intraperitoneally for 2, 4, 6 and 8 weeks, then immunosuppressed for an additional 6 weeks. Rezafungin administered for 4 weeks prevented P. murina from developing infection after rezafungin was discontinued. In the treatment model, immunosuppressed mice with P. murina pneumonia were treated with rezafungin 20 mg/kg 3×/week intraperitoneally for 2, 4, 6 and 8 weeks. Treatment with rezafungin for 8 weeks resulted in elimination of P. murina. Collectively, these studies showed that rezafungin could both prevent infection and eliminate P. murina from the lungs of mice. These findings support the obligate role of sexual reproduction for survival and growth of Pneumocystis spp. and warrant further investigation for treatment of P. jirovecii pneumonia in humans.
| S-EPMC8468546 | biostudies-literature
Project description:Although the role of adaptive immunity in fighting Pneumocystis infection is well known, the role of the innate, airway epithelium, responses remains largely unexplored. The concerted interaction of innate and adaptive responses is essential to successfully eradicate infection. Increased expression of goblet-cell-derived CLCA1 protein plus excess mucus in infant autopsy lungs and in murine models of primary Pneumocystis infection alert of innate immune system immunopathology associated to Pneumocystis infection. Nonetheless, whether blocking mucus-associated innate immune pathways decreases Pneumocystis-related immunopathology is unknown. Furthermore, current treatment of Pneumocystis pneumonia (PcP) relying on anti-Pneumocystis drugs plus steroids is not ideal because removes cellular immune responses against the fungal pathogen. In this study, we used the steroid-induced rat model of PcP to evaluate inflammation and mucus progression, and tested the effect of niflumic acid (NFA), a fenamate-type drug with potent CLCA1 blocker activity, in decreasing Pneumocystis-associated immunopathology. In this model, animals acquire Pneumocystis spontaneously and pneumonia develops owing to the steroids-induced immunodeficiency. Steroids led to decreased animal weight evidencing severe immunosuppression and to significant Pneumocystis-associated pulmonary edema as evidenced by wet-to-dry lung ratios that doubled those of uninfected animals. Inflammatory cuffing infiltrates were noticed first around lung blood vessels followed by bronchi, and both increased progressively. Similarly, airway epithelial and lumen mucus progressively increased. This occurred in parallel to increasing levels of MUC5AC and mCLCA3, the murine homolog of hCLCA1. Administration of NFA caused a significant decrease in total mucus, MUC5AC and mCLCA3 and also, in Pneumocystis-associated inflammation. Most relevant, NFA treatment improved survival at 8 weeks of steroids. Results suggest an important role of innate immune responses in immunopathology of steroid-induced PcP. They warrant evaluation of CLCA1 blockers as adjunctive therapy in this condition and describe a simple model to evaluate therapeutic interventions for steroid resistant mucus, a common condition in patients with chronic lung disease like asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis.
| S-EPMC6624676 | biostudies-literature
Project description:RationaleInfection with Pneumocystis, an opportunistic fungal pathogen, can result in fulminant pneumonia in the clinical setting of patients with immunosuppression. In murine models, Pneumocystis has previously been shown to induce a CD4+ T cell-dependent eosinophilic response in the lung capable of providing protection.ObjectivesWe sought to explore the role of Pneumocystis in generating asthma-like lung pathology, given the natural eosinophilic response to infection.MethodsPneumocystis infection or antigen treatment was used to induce asthma-like pathology in wild-type mice. The roles of CD4+ T cells and eosinophils were examined using antibody depletion and knockout mice, respectively. The presence of anti-Pneumocystis antibodies in human serum samples was detected by ELISA and Western blotting.Measurements and main resultsPneumocystis infection generates a strong type II response in the lung that requires CD4+ T cells. Pneumocystis infection was capable of priming a Th2 response similar to that of a commonly studied airway allergen, the house dust mite. Pneumocystis antigen treatment was also capable of inducing allergic inflammation in the lung, resulting in anti-Pneumocystis IgE production, goblet cell hyperplasia, and increased airway resistance. In the human population, patients with severe asthma had increased levels of anti-Pneumocystis IgG and IgE compared with healthy control subjects. Patients with severe asthma with elevated anti-Pneumocystis IgG levels had worsened symptom scores and lung parameters such as decreased forced expiratory volume and increased residual volume compared with patients with severe asthma who had low anti-Pneumocystis IgG.ConclusionsThe present study demonstrates for the first time, to our knowledge, that Pneumocystis is an airway allergen capable of inducing asthma-like lung pathology.
| S-EPMC5074654 | biostudies-literature