In silico predicted epitopes from the COOH-terminal extension of cysteine proteinase B inducing distinct immune responses during Leishmania (Leishmania) amazonensis experimental murine infection

<p>Abstract</p> <p>Background</p> <p><it>Leishmania </it>parasites have been reported to interfere and even subvert their host immune responses to enhance their chances of survival and proliferation. Experimental <it>Leishmania </it>infection in mice has been widely used in the identification of specific parasite virulence factors involved in the interaction with the host immune system. Cysteine-proteinase B (CPB) is an important virulence factor in parasites from the <it>Leishmania (Leishmania) mexicana </it>complex: it inhibits lymphocytes Th1 and/or promotes Th2 responses either through proteolytic activity or through epitopes derived from its COOH-terminal extension. In the present study we analyzed the effects of <it>Leishmania (Leishmania) amazonensis </it>CPB COOH-terminal extension-derived peptides on cell cultures from murine strains with distinct levels of susceptibility to infection: BALB/c, highly susceptible, and CBA, mildly resistant.</p> <p>Results</p> <p>Predicted epitopes, obtained by <it>in silico </it>mapping, displayed the ability to induce cell proliferation and expression of cytokines related to Th1 and Th2 responses. Furthermore, we applied <it>in silico </it>simulations to investigate how the MHC/epitopes interactions could be related to the immunomodulatory effects on cytokines, finding evidence that specific interaction patterns can be related to <it>in vitro </it>activities.</p> <p>Conclusions</p> <p>Based on our results, we consider that some peptides from the CPB COOH-terminal extension may influence host immune responses in the murine infection, thus helping <it>Leishmania </it>survival.</p

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Cysteine proteases as digestive enzymes in parasitic helminths.

We briefly review cysteine proteases (orthologs of mammalian cathepsins B, L, F, and C) that are expressed in flatworm and nematode parasites. Emphasis is placed on enzyme activities that have been functionally characterized, are associated with the parasite gut, and putatively contribute to degrading host proteins to absorbable nutrients [1-4]. Often, gut proteases are expressed as multigene families, as is the case with Fasciola [5] and Haemonchus [6], presumably expanding the range of substrates that can be degraded, not least during parasite migration through host tissues [5]. The application of the free-living planarian and Caenorhabditis elegans as investigative models for parasite cysteine proteases is discussed. Finally, because of their central nutritive contribution, targeting the component gut proteases with small-molecule chemical inhibitors and understanding their utility as vaccine candidates are active areas of research [7]

Cysteine proteases during larval migration and development of helminths in their final host

Submitted by Sandra Infurna ([email protected]) on 2019-02-18T16:18:13Z No. of bitstreams: 1 karinam_rebello_etal_IOC_2018.pdf: 885473 bytes, checksum: 0e7721ab8f0e94552a23fb53ce2c02c4 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2019-02-18T16:31:15Z (GMT) No. of bitstreams: 1 karinam_rebello_etal_IOC_2018.pdf: 885473 bytes, checksum: 0e7721ab8f0e94552a23fb53ce2c02c4 (MD5)Made available in DSpace on 2019-02-18T16:31:15Z (GMT). No. of bitstreams: 1 karinam_rebello_etal_IOC_2018.pdf: 885473 bytes, checksum: 0e7721ab8f0e94552a23fb53ce2c02c4 (MD5) Previous issue date: 2018New York University. Center for Genomics and Systems Biology. Department of Biology. New York, NY, USA.University of California San Diego. Skaggs School of Pharmacy and Pharmaceutical Sciences. Center for Discovery and Innovation in Parasitic Diseases. La Jolla, CA, USA.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Toxinologia. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Estudos Integrados em Protozoologia. Rio de Janeiro, RJ, Brasil.Queen’s University Belfast. Medical Biology Centre. School of Biological Sciences. Belfast, Northern Ireland, United Kingdom / University of Michigan. School of Medicine. Department of Microbiology and Immunology. Ann Arbor, Michigan, USA.Queen’s University Belfast. Medical Biology Centre. School of Biological Sciences. Belfast, Northern Ireland, United Kingdom.Lindsley F. Kimball Research Institute. New York Blood Center, New York, NY, USA.Neglected tropical diseases caused by metazoan parasites are major public health concerns, and therefore, new methods for their control and elimination are needed. Research over the last 25 years has revealed the vital contribution of cysteine proteases to invasion of and migration by (larval) helminth parasites through host tissues, in addition to their roles in embryogenesis, molting, egg hatching, and yolk degradation. Their central function to maintaining parasite survival in the host has made them prime intervention targets for novel drugs and vaccines. This review focuses on those helminth cysteine proteases that have been functionally characterized during the varied early stages of development in the human host and embryogenesis

Activity profiling of peptidases in Angiostrongylus costaricensis first-stage larvae and adult worms.

BACKGROUND:Angiostrongylus costaricensis is a relatively uncharacterized nematode that causes abdominal angiostrongyliasis in Latin America, a human parasitic disease. Currently, no effective pharmacological treatment for angiostrongyliasis exists. Peptidases are known to be druggable targets for a variety of diseases and are essential for several biological processes in parasites. Therefore, this study aimed to systematically characterize the peptidase activity of A. costaricensis in different developmental stages of this parasitic nematode. METHODOLOGY/PRINCIPAL FINDINGS:A library of diverse tetradecapeptides was incubated with cellular lysates from adult worms and from first-stage larvae (L1) and cleaved peptide products were identified by mass spectrometry. Lysates were also treated with class specific peptidase inhibitors to determine which enzyme class was responsible for the proteolytic activity. Peptidase activity from the four major mechanistic classes (aspartic, metallo, serine and cysteine) were detected in adult worm lysate, whereas aspartic, metallo and serine-peptidases were found in the larval lysates. In addition, the substrate specificity profile was found to vary at different pH values. CONCLUSIONS/SIGNIFICANCE:The proteolytic activities in adult worm and L1 lysates were characterized using a highly diversified library of peptide substrates and the activity was validated using a selection of fluorescent substrates. Taken together, peptidase signatures for different developmental stages of this parasite has improved our understanding of the disease pathogenesis and may be useful as potential drug targets or vaccine candidates

Morphological aspects of Angiostrongylus costaricensis by light andscanning electron microscopy

Made available in DSpace on 2015-08-19T13:49:41Z (GMT). No. of bitstreams: 2 license.txt: 1914 bytes, checksum: 7d48279ffeed55da8dfe2f8e81f3b81f (MD5) rubens_mennabarreto_etal_IOC-2013.pdf: 4646384 bytes, checksum: 617f107c5dda58f2e8ba2a43f40b8268 (MD5) Previous issue date: 2013Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Toxinologia. Laboratório de Patologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biologia Celular. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Biofísica Carlos Chagas Filho. Laboratório de Biologia de Helmintos Otto Wucherer. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Patologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Toxinologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Toxinologia. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro - Campus Macaé. Grupo de Sistemática e Biologia Evolutiva (GSE). Macaé, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Patologia. Rio de Janeiro, RJ, Brasil.tAngiostrongylus costaricensis is a parasitic nematode that can cause severe gastrointestinal disease,known as abdominal angiostrongiliasis, in humans. This paper presents the characterization of first-and third-stage larvae and male and female adult worms of A. costaricensis by scanning electron andlight microscopy. Several novel anatomical structures were identified by scanning electron microscopy,including details of the cuticular striations of the spicules in male worms and a protective flap of the cuti-cle covering the vulvar aperture in female worms. Other taxonomic features revealed by light microscopyinclude the gubernaculum and the esophageal–intestinal valve. The use of two microscopy techniquesallowed a detailed characterization of the morphology of this nematode. A number of previously identi-fied taxonomic features, such as the striated nature of the spicules and the lateral alae were confirmed;however, the use of scanning electron microscopy resulted in a reassessment of the correct number ofpapillae distributed around the oral opening and behind the cloacal opening. These observations, in com-bination with light microscopy-based characterization of the gubernaculum and esophageal valves, haveallowed a more detailed description of this nematode taxonomy

Miltefosine-Lopinavir Combination Therapy Against Leishmania infantum Infection: In vitro and in vivo Approaches

Submitted by Sandra Infurna ([email protected]) on 2019-09-05T13:19:01Z No. of bitstreams: 1 KarinaRebello_ClaudiaMLevy_etal_IOC_2019.pdf: 1447207 bytes, checksum: 953ae8b6393c6500175c5aca485c5210 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2019-09-05T13:29:54Z (GMT) No. of bitstreams: 1 KarinaRebello_ClaudiaMLevy_etal_IOC_2019.pdf: 1447207 bytes, checksum: 953ae8b6393c6500175c5aca485c5210 (MD5)Made available in DSpace on 2019-09-05T13:29:54Z (GMT). No. of bitstreams: 1 KarinaRebello_ClaudiaMLevy_etal_IOC_2019.pdf: 1447207 bytes, checksum: 953ae8b6393c6500175c5aca485c5210 (MD5) Previous issue date: 2019Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Estudos Integrados em Protozoologia. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Bioquímica de Tripanosomatídeos. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Síntese de Substâncias no Combate a Doenças Tropicais. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Farmanguinhos. Laboratório de Síntese de Substâncias no Combate a Doenças Tropicais. Rio de Janeiro, RJ. Brasil.Universidade Federal do Rio de Janeiro. Instituto de Microbiologia Paulo de Góes. Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Microbiologia Paulo de Góes. Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Bioquímica de Tripanosomatídeos. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Estudos Integrados em Protozoologia. Rio de Janeiro, RJ. Brasil.Concurrently, leishmaniasis and AIDS are global public health issues and the overlap between these diseases adds additional treats to the management of co-infected patients. Lopinavir (LPV) has a well characterized anti-HIV and leishmanicidal action, and to analyze its combined action with miltefosine (MFS) could help to envisage strategies to the management of co-infected patients. Here, we evaluate the interaction between LPV and MFS against Leishmania infantum infection by in vitro and in vivo approaches. The effect of the compounds alone or in association was assessed for 72 h in mouse peritoneal macrophages infected with L. infantum by the determination of the IC50s and FICIs. Subsequently, mice were orally treated twice daily during 5 days with the compounds alone or in association and evaluated after 30 days. The in vitro assays revealed an IC50 of 0.24 μM and 9.89 μM of MFS and LPV, respectively, and an additive effect of the compounds (FICI 1.28). The in vivo assays revealed that LPV alone reduced the parasite load in the spleen and liver by 52 and 40%, respectively. The combined treatment of infected BALB/c mice revealed that the compounds alone required at least two times higher doses than when administered in association to virtually eliminate the parasite. Mice plasma biochemical parameters assessed revealed that the combined therapy did not present any relevant hepatotoxicity. In conclusion, the association of MFS with LPV allowed a reduction in each compound concentration to achieve the same outcome in the treatment of visceral leishmaniasis. Although a pronounced synergistic effect was not evidenced, it does not discard that such combination could be useful in humans co-infected with HIV and Leishmania parasites