Two new thiocarboxylic acids, p-bromothiobenzoic BTA and thionaphthoic acid TNA, and five new hom... more Two new thiocarboxylic acids, p-bromothiobenzoic BTA and thionaphthoic acid TNA, and five new homo- and heteroleptic bismuth(iii) compounds derived from thiocarboxylic acids: [Bi{S(C=O)C6H4Br}3] 1, [PhBi{S(C=O)C6H4Br}2] 2, [Bi{S(C=O)C10H7}3] 3, [PhBi{S(C=O)C10H7}2] 4, and [Ph2Bi{S(C=O)C10H7}] 5 were synthesised and fully characterised. The solid-state structure of complex [PhBi{S(C=O)C6H4Br}2] 2 was confirmed by X-ray crystallography. In complex 2, the two thiocarboxylate ligands are coordinated to the bismuth(iii) centre in a didentate fashion, forming a distorted octahedral geometry in which the phenyl group and the lone pair are oriented axial to the plane formed by the two thiocarboxylate ligands. Long-range Bi–S interactions (3.54 Å) link these monomeric units to form a one-dimensional polymer. These compounds, in addition to six previously synthesised complexes: [Bi{SC(=O)C6H5}3] 6, [PhBi{SC(=O)C6H5}2] 7, [Ph2Bi{SC(=O)C6H5}] 8, [Bi{SC(=O)C6H4NO2}3] 9, [PhBi{SC(=O)C6H4NO2}2] 10, and [PhBi{SC(=O)C6H4SO3}] 11, and the thiocarboxylic acids themselves, were assessed for their in vitro activity against Leishmania major promastigotes, and for general toxicity against human fibroblast cells. The thiocarboxylic acids, with the exception of thiobenzoic acid and sulfothiobenzoic acid, were toxic to both L. major parasites and the mammalian cells at high concentrations of 50–100 μM. The bismuth(iii) thiocarboxylate derivatives proved to be more active than the corresponding acids. Among these, the heteroleptic phenyl-substituted bismuth(iii) complexes 2, 4, 5, and 7 were highly active, showing IC50 (half maximal inhibitory concentration) values ranging from 0.39 to 4.69 μM, and a clear ligand dependence on activity.
Novel influenza viruses often cause differential infection patterns across different age groups, ... more Novel influenza viruses often cause differential infection patterns across different age groups, an effect that is defined as heterogeneous demographic susceptibility. This occurred during the A/H2N2 pandemic, when children experienced higher influenza attack rates than adults. Since the recognition of conserved epitopes across influenza subtypes by CD8 ؉ cytotoxic T lymphocytes (CTLs) limit influenza disease, we hypothesized that conservation of CTL antigenic peptides (Ag-p) in viruses circulating before the pH2N2-1957 may have resulted in differential CTL immunity. We compared viruses isolated in the years preceding the pandemic (1941 to 1957) to which children and adults were exposed to viruses circulating decades earlier (1918 to 1940), which could infect adults only. Consistent with phylogenetic models, influenza viruses circulating from 1941 to 1957, which infected children, shared with pH2N2 the majority (ϳ89%) of the CTL peptides within the most immunogenic nucleoprotein, matrix 1, and polymerase basic 1, thus providing evidence for minimal pH2N2 CTL escape in children. Our study, however, identified potential CTL immune evasion from pH2N2 irrespective of age, within HLA-A*03:01 ؉ individuals for PB1 471-L473V/N476I variants and HLA-B*15:01 ؉ population for NP 404-414-V408I mutant. Further experiments using the murine model of B-cell-deficient mice showed that multiple influenza infections resulted in superior protection from influenza-induced morbidity, coinciding with accumulation of tissue-resident memory CD8 ؉ T cells in the lung. Our study suggests that protection against H2N2-1957 pandemic influenza was most likely linked to the number of influenza virus infections prior to the pandemic challenge rather than differential preexisting CTL immunity. Thus, the regimen of a CTL-based vaccine/vaccine-component may benefit from periodic boosting to achieve fully protective, asymptomatic influenza infection. IMPORTANCE Due to a lack of cross-reactive neutralizing antibodies, children are particularly susceptible to influenza infections caused by novel viral strains. Preexisting T cell immunity directed at conserved viral regions, however, can provide protection against influenza viruses, promote rapid recovery and better clinical outcomes. When we asked whether high susceptibility of children (compared to adults) to the pandemic H2N2 influenza strain was associated with immune evasion from T-cell immunity, we found high conservation within T-cell antigenic regions in pandemic H2N2. However, the number of influenza infections prior to the challenge was linked to protective, asymptomatic infections and establishment of tissue-resident memory T cells. Our study supports development of vaccines that prime and boost T cells to elicit cross-strain protective T cells, especially tissueresident memory T cells, for lifelong immunity against distinct influenza viruses.
Related Article: Yih Ching Ong, Victoria L. Blair, Lukasz Kedzierski, Philip C. Andrews|2014|Dalt... more Related Article: Yih Ching Ong, Victoria L. Blair, Lukasz Kedzierski, Philip C. Andrews|2014|Dalton Trans.|43|12904|doi:10.1039/C4DT00957F
FluMist has been used in children and adults for more than 10 years. As pre-existing CD8 + T cell... more FluMist has been used in children and adults for more than 10 years. As pre-existing CD8 + T cell memory pools can provide heterologous immunity against distinct influenza viruses, it is important to understand influenza-specific CD8 + T cell responses elicited by different live attenuated influenza virus (LAIV) regimens. In this study, we immunized mice intranasally with two different doses of live-attenuated PR8 virus (PR8 ts, H1N1), low and high, and then assessed protective efficacy by challenging animals with heterosubtypic X31-H3N2 virus at 6 weeks postvaccination. Different LAIV doses elicited influenza-specific CD8 + T cell responses in lungs and spleen, but unexpectedly not in bronchoalveolar lavage. Interestingly, the immunodominance hierarchy at the acute phase after immunization varied depending on the LAIV dose; however, these differences disappeared at 6 weeks post-vaccination, resulting in generation of comparable CD8 + T cell memory pools. After vaccination with either dose, sufficient numbers of specific CD8 + T cells were generated for recall and protection of mice against heterosubtypic H1N1fiH3N2 challenge. As a result, immunized mice displayed reduced weight loss, diminished inflammatory responses and lower viral titres in lungs, when compared to unvaccinated animals. Interestingly, the higher dose led to enhanced viral clearance on day 5 post-challenge, though this was not associated with increased CD8 + T cell responses, but with higher levels of nonneutralizing antibodies against the priming virus. Our study suggests that, while different LAIV doses result in distinct immune profiles, even a low dose produces sufficient protective CD8 + T cell memory against challenge infection, though the high dose results in more rapid viral clearance and reduced inflammation.
Virus infections of the central nervous system (CNS) cause important diseases of humans and anima... more Virus infections of the central nervous system (CNS) cause important diseases of humans and animals. As in other tissues, innate antiviral responses mediated by type I interferons (IFNs) are crucially important in controlling CNS virus infections. The maturity of neuronal populations is an established critical factor determining the outcome of CNS virus infection. Using primary cultures of mouse cortical neurons, we investigated the relationships between neuronal maturation, type I IFN responses, and the outcome of Semliki Forest virus infection. The virus replicated better, infected more cells, and produced higher titres of infectious viruses in immature neurons. Complete transcriptome analysis demonstrated that resting immature neurons have low transcriptional competence to mount antiviral responses. They had no detectable transcription of the genes Ddx58 and Ifih1, which encode key RNA virus cytoplasmic sensors RIG-I and MDA5, and very low expression of genes encoding key regulators of associated signalling pathways. Upon infection, immature neurons failed to mount an antiviral response as ev-idenced by their failure to produce chemokines, IFNs, and other cytokines. Treatment of immature neurons with exogenous IFNβ prior to infection resulted in antiviral responses and lower levels of virus replication and infectious virus production. In contrast, resting mature neurons generated a robust antiviral response. This was augmented by pretreatment with IFNβ. Infection of mature neurons derived from IFNAR −/− mice did not make an antiviral response and replicated virus to high levels.
Conclusion: Our study demonstrates the potential of using scRNAseq of intestinal biopsies not onl... more Conclusion: Our study demonstrates the potential of using scRNAseq of intestinal biopsies not only to characterize the mechanism of action of tofacitinib, but also to describe the cellular events associated with response to this therapeutic intervention. Moreover, we show the potential of scR-NAseq to identify predictors of response to tofacitinib in patients with UC.
Influenza and Other Respiratory Viruses, Jun 25, 2020
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Comparative stability, cytotoxicity and anti-leishmanial activity of analogous organometallic Sb(... more Comparative stability, cytotoxicity and anti-leishmanial activity of analogous organometallic Sb(V) and Bi(V) acetato complexes: Sb confirms potential while Bi fails the test
A series of eight alkyl gallium complexes of general formulae [GaMe 2 (L)] and [Ga(Me) 2 L] have ... more A series of eight alkyl gallium complexes of general formulae [GaMe 2 (L)] and [Ga(Me) 2 L] have been synthesised, characterised and their antimicrobial activity against bacteria, cancer cells and Leishmania assessed. All eight complexes are novel, with the solid-state structures of all complexes successfully authenticated by single crystal X-ray diffraction. The dimethyl complexes all adopt a four-coordinate tetrahedral confirmation, while the monomethyl complexes are five-coordinate trigonal bipyramidal. All complexes were screened for their anti-bacterial activity either by solution state diffusion, or a solidstate stab test. The five soluble complexes underwent testing against two differing mammalian cell controls, with excellent selectivity observed against COS-7 cells, with an IC 50 range of 88.5 mM to !100 mM. Each soluble complex was also tested for their anti-cancer capabilities, with no significant activity observed. Excellent activity was exhibited against the protozoan parasite Leishmania major (strain: V121) in both the promastigote and amastigote forms, with IC 50 values ranging from 1.11 mM e13.4 mM for their anti-promastigote activity and % infection values of 3.5% ± 0.65e11.5% ± 0.65 for the more clinically relevant amastigote. Selectivity indices for each were found to be in the ranges of 6.61 e64.7, with significant selectivity noted for two of the complexes. At minimum, the gallium complexes show a 3-fold enhancement in activity towards the Leishmaniaamastigotes over the parent quinolinols alone.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Structural influences on the activity of bismuth(III) indole-carboxylato complexes towards Helicobacter pylori and Leishmania
Plasmodium yoelii merozoite surface protein 4/5 (PyMSP4/5), expressed as a recombinant protein, w... more Plasmodium yoelii merozoite surface protein 4/5 (PyMSP4/5), expressed as a recombinant protein, was highly effective at protecting mice against lethal challenge with P. yoelii. There was a significant correlation between prechallenge antibody levels and peak parasitemia, suggesting that the homologues of PyMSP4/5 in Plasmodium falciparum are promising components of a subunit vaccine against malaria.
Bismuth(III) complexes of NSAIDs (Non-Steroidal Anti Inflammatory Drugs) and substituted benzoic ... more Bismuth(III) complexes of NSAIDs (Non-Steroidal Anti Inflammatory Drugs) and substituted benzoic acids (omethoxybenzoic acid, m-methoxybenzoic acid, o-nitrobenzoic acid, 3,5-diacetamidobenzoic acid, and 5-[(R/S)-2,3-dihydroxypropyl carbamoyl]-2-pyridine carboxylic acid) have been synthesised and fully characterised. Two new bis-carboxylato bismuth complexes have been characterised by single crystal X-ray diffraction, namely [PhBi (o-MeOC 6 H 4 CO 2) 2 (bipy)]•0.5EtOH (bipy = 2,2'-bipyridine) and [PhBi(C 9 H 11 N 2 O 3 CO 2) 2 (H 2 O)]•6H 2 O. All compounds were tested against the parasite Leishmania major promastigotes for their anti-Leishmanial activity and were further assessed for their toxicity to mammalian cells. The NSAID free acids and their bismuth derivatives show negligible anti-Leishmanial activity at concentrations 1.95 to 250 μg/mL against the promastigotes of L. major whereas in the case of mammalian cells only bismuth complexes of naproxen and mefenamic acid have significant effect at concentration ≥ 250 μg/mL. The bismuth(III) complexes of substituted benzoic acids show significant anti-Leishmanial activity against the promastigotes of L. major V121 at very low concentrations while their respective free carboxylic acids show no effective activity. However, the bismuth compounds inhibit the growth of the mammalian cells at all concentrations studied (1.95 to 500 μg/mL) following 48 h incubation. The comparatively low toxicity of BiCl 3 and Bi(NO 3) 3 , suggests that overall toxicity of bismuth complexes towards the parasite is both ligand and metal dependent.
Even after 70 years, pentavalent antimonials sodium stibogluconate and meglumine antimoniate rema... more Even after 70 years, pentavalent antimonials sodium stibogluconate and meglumine antimoniate remain the most important and cost-effective antileishmanial drugs. However, the drugs cannot be delivered orally and treatment involves intravascular or intramuscular injections for 28 days under strict medical monitoring due to the toxicity of Sb(III). The main alternatives, amphotericin B, pentamidine and miltefosine, are expensive and not without their own problems. Bismuth sits below antimony in the periodic table and is considered to be relatively nontoxic to humans while being capable of providing powerful antimicrobial activity. This review describes recent efforts into developing antileishmanial Bi(III) and Bi(V) drugs, which may resemble Sb analogs in effect and mode-of-action while providing lower mammalian cell toxicity and opportunities of oral delivery. Within the last 10 years, various studies concerning bismuth-based compounds as potential antileishmanial agents have been published. This review seeks to summarize the relevant studies and draw a conclusion as to whether bismuth complexes have the potential to be effective drugs.
Immune responses induced to DNA vaccination vary considerably and depend on a variety of factors,... more Immune responses induced to DNA vaccination vary considerably and depend on a variety of factors, including the physical form in which the antigen is expressed by target cells and presented to the immune system. Data on the effect of these factors will aid improved design of DNA vaccines and facilitate their further development. We examined the effect of different forms of surface anchoring on the immunogenicity of a DNA vaccine. A number of constructs were generated encoding Plasmodium yoelii merozoite surface protein 4/5 (PyMSP4/5) with or without its C-terminal glycosylphosphatidylinositol (GPI) attachment signal, replacing the endogenous GPI signal of PyMSP4/5 with that of mouse decay-accelerating factor (DAF), a well-established model for GPI-anchoring in mammalian cells, or the transmembrane anchor and cytoplasmic tail of mouse tissue factor (TF). All constructs were demonstrated to express the full-length PyMSP4/5 in transfected COS cells and induce PyMSP4/5-specific antibodies in mice. The GPI attachment signal of PyMSP4/5 was found to function poorly in mammalian cells and result in a much lower level of PyMSP4/5 expression in vitro than its mammalian counterpart. The DNA vaccine containing the mammalian GPI attachment signal induced the highest levels of antibodies and impacted Ig isotype distribution, consistent with the presence of a CD1-restricted pathway of Ig formation to GPI-anchored membrane proteins. Despite the induction of specific antibodies, none of these DNA vaccines induced sufficient levels of antibodies to protect mice against a lethal challenge with P. yoelii.
Leishmania are protozoan parasites responsible for a spectrum of diseases collectively known as l... more Leishmania are protozoan parasites responsible for a spectrum of diseases collectively known as leishmaniasis. The disease is a significant health problem in many regions of the world and emerges as a serious co-infection in HIV-positive individuals. Current treatment of the disease is based on a limited number of chemotherapeutic agents which are rapidly becoming ineffective, and are characterized by high toxicity and cost. This review focuses on recent advances in antileishmanial drug development and improvements to current treatment options. Novel approaches currently used to identify leishmanicidal compounds as diverse as antimicrobial peptides and natural plant extracts are described in this review.
Leishmania are protozoan parasites spread by a sandfly insect vector and causing a spectrum of di... more Leishmania are protozoan parasites spread by a sandfly insect vector and causing a spectrum of diseases collectively known as leishmaniasis. The disease is a significant health problem in many parts of the world, resulting in an estimated 1•3 million new cases and 30 000 deaths annually. Current treatment is based on chemotherapy, which is difficult to administer, expensive and becoming ineffective in several endemic regions. To date there is no vaccine against leishmaniasis, although extensive evidence from studies in animal models indicates that solid protection can be achieved upon immunization. This review focuses on immune responses to Leishmania in both cutaneous and visceral forms of the disease, pointing to the complexity of the immune response and to a range of evasive mechanisms utilized by the parasite to bypass those responses. The amalgam of innate and acquired immunity combined with the paucity of data on the human immune response is one of the major problems currently hampering vaccine development and implementation.
All reactions were conducted using 5.0 mmol of antimony(V) dibromide precursor and 10.0 mmol of p... more All reactions were conducted using 5.0 mmol of antimony(V) dibromide precursor and 10.0 mmol of potassium or sodium salt of carboxylic acid. Aryl substituted antimony(V) dibromide was ground together with the chosen carboxylic acid salt and dried in vacuo prior to use. The mixture of reagents were placed in a Schlenk flask with dried toluene (ca 100 mL) and stirred for 12 hours. The salt(s) formed were filtered off and the resulting clear solution was removed under reduced pressure to yield a solid residue. Synthesis of bis-(2-thiophenecarboxylato)triphenylantimony(V), [SbPh 3 (C 4 H 3 SCO 2) 2 ], 12 Reaction of triphenylantimony(V) dibromide (2.56 g, 5 mmol) with the potassium salt of 2-thiophenecarboxylic acid (1.66 g, 10 mmol) was performed and purified according to GP, producing a colourless solid. This was identified as 12.
Two new thiocarboxylic acids, p-bromothiobenzoic BTA and thionaphthoic acid TNA, and five new hom... more Two new thiocarboxylic acids, p-bromothiobenzoic BTA and thionaphthoic acid TNA, and five new homo- and heteroleptic bismuth(iii) compounds derived from thiocarboxylic acids: [Bi{S(C=O)C6H4Br}3] 1, [PhBi{S(C=O)C6H4Br}2] 2, [Bi{S(C=O)C10H7}3] 3, [PhBi{S(C=O)C10H7}2] 4, and [Ph2Bi{S(C=O)C10H7}] 5 were synthesised and fully characterised. The solid-state structure of complex [PhBi{S(C=O)C6H4Br}2] 2 was confirmed by X-ray crystallography. In complex 2, the two thiocarboxylate ligands are coordinated to the bismuth(iii) centre in a didentate fashion, forming a distorted octahedral geometry in which the phenyl group and the lone pair are oriented axial to the plane formed by the two thiocarboxylate ligands. Long-range Bi–S interactions (3.54 Å) link these monomeric units to form a one-dimensional polymer. These compounds, in addition to six previously synthesised complexes: [Bi{SC(=O)C6H5}3] 6, [PhBi{SC(=O)C6H5}2] 7, [Ph2Bi{SC(=O)C6H5}] 8, [Bi{SC(=O)C6H4NO2}3] 9, [PhBi{SC(=O)C6H4NO2}2] 10, and [PhBi{SC(=O)C6H4SO3}] 11, and the thiocarboxylic acids themselves, were assessed for their in vitro activity against Leishmania major promastigotes, and for general toxicity against human fibroblast cells. The thiocarboxylic acids, with the exception of thiobenzoic acid and sulfothiobenzoic acid, were toxic to both L. major parasites and the mammalian cells at high concentrations of 50–100 μM. The bismuth(iii) thiocarboxylate derivatives proved to be more active than the corresponding acids. Among these, the heteroleptic phenyl-substituted bismuth(iii) complexes 2, 4, 5, and 7 were highly active, showing IC50 (half maximal inhibitory concentration) values ranging from 0.39 to 4.69 μM, and a clear ligand dependence on activity.
Novel influenza viruses often cause differential infection patterns across different age groups, ... more Novel influenza viruses often cause differential infection patterns across different age groups, an effect that is defined as heterogeneous demographic susceptibility. This occurred during the A/H2N2 pandemic, when children experienced higher influenza attack rates than adults. Since the recognition of conserved epitopes across influenza subtypes by CD8 ؉ cytotoxic T lymphocytes (CTLs) limit influenza disease, we hypothesized that conservation of CTL antigenic peptides (Ag-p) in viruses circulating before the pH2N2-1957 may have resulted in differential CTL immunity. We compared viruses isolated in the years preceding the pandemic (1941 to 1957) to which children and adults were exposed to viruses circulating decades earlier (1918 to 1940), which could infect adults only. Consistent with phylogenetic models, influenza viruses circulating from 1941 to 1957, which infected children, shared with pH2N2 the majority (ϳ89%) of the CTL peptides within the most immunogenic nucleoprotein, matrix 1, and polymerase basic 1, thus providing evidence for minimal pH2N2 CTL escape in children. Our study, however, identified potential CTL immune evasion from pH2N2 irrespective of age, within HLA-A*03:01 ؉ individuals for PB1 471-L473V/N476I variants and HLA-B*15:01 ؉ population for NP 404-414-V408I mutant. Further experiments using the murine model of B-cell-deficient mice showed that multiple influenza infections resulted in superior protection from influenza-induced morbidity, coinciding with accumulation of tissue-resident memory CD8 ؉ T cells in the lung. Our study suggests that protection against H2N2-1957 pandemic influenza was most likely linked to the number of influenza virus infections prior to the pandemic challenge rather than differential preexisting CTL immunity. Thus, the regimen of a CTL-based vaccine/vaccine-component may benefit from periodic boosting to achieve fully protective, asymptomatic influenza infection. IMPORTANCE Due to a lack of cross-reactive neutralizing antibodies, children are particularly susceptible to influenza infections caused by novel viral strains. Preexisting T cell immunity directed at conserved viral regions, however, can provide protection against influenza viruses, promote rapid recovery and better clinical outcomes. When we asked whether high susceptibility of children (compared to adults) to the pandemic H2N2 influenza strain was associated with immune evasion from T-cell immunity, we found high conservation within T-cell antigenic regions in pandemic H2N2. However, the number of influenza infections prior to the challenge was linked to protective, asymptomatic infections and establishment of tissue-resident memory T cells. Our study supports development of vaccines that prime and boost T cells to elicit cross-strain protective T cells, especially tissueresident memory T cells, for lifelong immunity against distinct influenza viruses.
Related Article: Yih Ching Ong, Victoria L. Blair, Lukasz Kedzierski, Philip C. Andrews|2014|Dalt... more Related Article: Yih Ching Ong, Victoria L. Blair, Lukasz Kedzierski, Philip C. Andrews|2014|Dalton Trans.|43|12904|doi:10.1039/C4DT00957F
FluMist has been used in children and adults for more than 10 years. As pre-existing CD8 + T cell... more FluMist has been used in children and adults for more than 10 years. As pre-existing CD8 + T cell memory pools can provide heterologous immunity against distinct influenza viruses, it is important to understand influenza-specific CD8 + T cell responses elicited by different live attenuated influenza virus (LAIV) regimens. In this study, we immunized mice intranasally with two different doses of live-attenuated PR8 virus (PR8 ts, H1N1), low and high, and then assessed protective efficacy by challenging animals with heterosubtypic X31-H3N2 virus at 6 weeks postvaccination. Different LAIV doses elicited influenza-specific CD8 + T cell responses in lungs and spleen, but unexpectedly not in bronchoalveolar lavage. Interestingly, the immunodominance hierarchy at the acute phase after immunization varied depending on the LAIV dose; however, these differences disappeared at 6 weeks post-vaccination, resulting in generation of comparable CD8 + T cell memory pools. After vaccination with either dose, sufficient numbers of specific CD8 + T cells were generated for recall and protection of mice against heterosubtypic H1N1fiH3N2 challenge. As a result, immunized mice displayed reduced weight loss, diminished inflammatory responses and lower viral titres in lungs, when compared to unvaccinated animals. Interestingly, the higher dose led to enhanced viral clearance on day 5 post-challenge, though this was not associated with increased CD8 + T cell responses, but with higher levels of nonneutralizing antibodies against the priming virus. Our study suggests that, while different LAIV doses result in distinct immune profiles, even a low dose produces sufficient protective CD8 + T cell memory against challenge infection, though the high dose results in more rapid viral clearance and reduced inflammation.
Virus infections of the central nervous system (CNS) cause important diseases of humans and anima... more Virus infections of the central nervous system (CNS) cause important diseases of humans and animals. As in other tissues, innate antiviral responses mediated by type I interferons (IFNs) are crucially important in controlling CNS virus infections. The maturity of neuronal populations is an established critical factor determining the outcome of CNS virus infection. Using primary cultures of mouse cortical neurons, we investigated the relationships between neuronal maturation, type I IFN responses, and the outcome of Semliki Forest virus infection. The virus replicated better, infected more cells, and produced higher titres of infectious viruses in immature neurons. Complete transcriptome analysis demonstrated that resting immature neurons have low transcriptional competence to mount antiviral responses. They had no detectable transcription of the genes Ddx58 and Ifih1, which encode key RNA virus cytoplasmic sensors RIG-I and MDA5, and very low expression of genes encoding key regulators of associated signalling pathways. Upon infection, immature neurons failed to mount an antiviral response as ev-idenced by their failure to produce chemokines, IFNs, and other cytokines. Treatment of immature neurons with exogenous IFNβ prior to infection resulted in antiviral responses and lower levels of virus replication and infectious virus production. In contrast, resting mature neurons generated a robust antiviral response. This was augmented by pretreatment with IFNβ. Infection of mature neurons derived from IFNAR −/− mice did not make an antiviral response and replicated virus to high levels.
Conclusion: Our study demonstrates the potential of using scRNAseq of intestinal biopsies not onl... more Conclusion: Our study demonstrates the potential of using scRNAseq of intestinal biopsies not only to characterize the mechanism of action of tofacitinib, but also to describe the cellular events associated with response to this therapeutic intervention. Moreover, we show the potential of scR-NAseq to identify predictors of response to tofacitinib in patients with UC.
Influenza and Other Respiratory Viruses, Jun 25, 2020
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Comparative stability, cytotoxicity and anti-leishmanial activity of analogous organometallic Sb(... more Comparative stability, cytotoxicity and anti-leishmanial activity of analogous organometallic Sb(V) and Bi(V) acetato complexes: Sb confirms potential while Bi fails the test
A series of eight alkyl gallium complexes of general formulae [GaMe 2 (L)] and [Ga(Me) 2 L] have ... more A series of eight alkyl gallium complexes of general formulae [GaMe 2 (L)] and [Ga(Me) 2 L] have been synthesised, characterised and their antimicrobial activity against bacteria, cancer cells and Leishmania assessed. All eight complexes are novel, with the solid-state structures of all complexes successfully authenticated by single crystal X-ray diffraction. The dimethyl complexes all adopt a four-coordinate tetrahedral confirmation, while the monomethyl complexes are five-coordinate trigonal bipyramidal. All complexes were screened for their anti-bacterial activity either by solution state diffusion, or a solidstate stab test. The five soluble complexes underwent testing against two differing mammalian cell controls, with excellent selectivity observed against COS-7 cells, with an IC 50 range of 88.5 mM to !100 mM. Each soluble complex was also tested for their anti-cancer capabilities, with no significant activity observed. Excellent activity was exhibited against the protozoan parasite Leishmania major (strain: V121) in both the promastigote and amastigote forms, with IC 50 values ranging from 1.11 mM e13.4 mM for their anti-promastigote activity and % infection values of 3.5% ± 0.65e11.5% ± 0.65 for the more clinically relevant amastigote. Selectivity indices for each were found to be in the ranges of 6.61 e64.7, with significant selectivity noted for two of the complexes. At minimum, the gallium complexes show a 3-fold enhancement in activity towards the Leishmaniaamastigotes over the parent quinolinols alone.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Structural influences on the activity of bismuth(III) indole-carboxylato complexes towards Helicobacter pylori and Leishmania
Plasmodium yoelii merozoite surface protein 4/5 (PyMSP4/5), expressed as a recombinant protein, w... more Plasmodium yoelii merozoite surface protein 4/5 (PyMSP4/5), expressed as a recombinant protein, was highly effective at protecting mice against lethal challenge with P. yoelii. There was a significant correlation between prechallenge antibody levels and peak parasitemia, suggesting that the homologues of PyMSP4/5 in Plasmodium falciparum are promising components of a subunit vaccine against malaria.
Bismuth(III) complexes of NSAIDs (Non-Steroidal Anti Inflammatory Drugs) and substituted benzoic ... more Bismuth(III) complexes of NSAIDs (Non-Steroidal Anti Inflammatory Drugs) and substituted benzoic acids (omethoxybenzoic acid, m-methoxybenzoic acid, o-nitrobenzoic acid, 3,5-diacetamidobenzoic acid, and 5-[(R/S)-2,3-dihydroxypropyl carbamoyl]-2-pyridine carboxylic acid) have been synthesised and fully characterised. Two new bis-carboxylato bismuth complexes have been characterised by single crystal X-ray diffraction, namely [PhBi (o-MeOC 6 H 4 CO 2) 2 (bipy)]•0.5EtOH (bipy = 2,2'-bipyridine) and [PhBi(C 9 H 11 N 2 O 3 CO 2) 2 (H 2 O)]•6H 2 O. All compounds were tested against the parasite Leishmania major promastigotes for their anti-Leishmanial activity and were further assessed for their toxicity to mammalian cells. The NSAID free acids and their bismuth derivatives show negligible anti-Leishmanial activity at concentrations 1.95 to 250 μg/mL against the promastigotes of L. major whereas in the case of mammalian cells only bismuth complexes of naproxen and mefenamic acid have significant effect at concentration ≥ 250 μg/mL. The bismuth(III) complexes of substituted benzoic acids show significant anti-Leishmanial activity against the promastigotes of L. major V121 at very low concentrations while their respective free carboxylic acids show no effective activity. However, the bismuth compounds inhibit the growth of the mammalian cells at all concentrations studied (1.95 to 500 μg/mL) following 48 h incubation. The comparatively low toxicity of BiCl 3 and Bi(NO 3) 3 , suggests that overall toxicity of bismuth complexes towards the parasite is both ligand and metal dependent.
Even after 70 years, pentavalent antimonials sodium stibogluconate and meglumine antimoniate rema... more Even after 70 years, pentavalent antimonials sodium stibogluconate and meglumine antimoniate remain the most important and cost-effective antileishmanial drugs. However, the drugs cannot be delivered orally and treatment involves intravascular or intramuscular injections for 28 days under strict medical monitoring due to the toxicity of Sb(III). The main alternatives, amphotericin B, pentamidine and miltefosine, are expensive and not without their own problems. Bismuth sits below antimony in the periodic table and is considered to be relatively nontoxic to humans while being capable of providing powerful antimicrobial activity. This review describes recent efforts into developing antileishmanial Bi(III) and Bi(V) drugs, which may resemble Sb analogs in effect and mode-of-action while providing lower mammalian cell toxicity and opportunities of oral delivery. Within the last 10 years, various studies concerning bismuth-based compounds as potential antileishmanial agents have been published. This review seeks to summarize the relevant studies and draw a conclusion as to whether bismuth complexes have the potential to be effective drugs.
Immune responses induced to DNA vaccination vary considerably and depend on a variety of factors,... more Immune responses induced to DNA vaccination vary considerably and depend on a variety of factors, including the physical form in which the antigen is expressed by target cells and presented to the immune system. Data on the effect of these factors will aid improved design of DNA vaccines and facilitate their further development. We examined the effect of different forms of surface anchoring on the immunogenicity of a DNA vaccine. A number of constructs were generated encoding Plasmodium yoelii merozoite surface protein 4/5 (PyMSP4/5) with or without its C-terminal glycosylphosphatidylinositol (GPI) attachment signal, replacing the endogenous GPI signal of PyMSP4/5 with that of mouse decay-accelerating factor (DAF), a well-established model for GPI-anchoring in mammalian cells, or the transmembrane anchor and cytoplasmic tail of mouse tissue factor (TF). All constructs were demonstrated to express the full-length PyMSP4/5 in transfected COS cells and induce PyMSP4/5-specific antibodies in mice. The GPI attachment signal of PyMSP4/5 was found to function poorly in mammalian cells and result in a much lower level of PyMSP4/5 expression in vitro than its mammalian counterpart. The DNA vaccine containing the mammalian GPI attachment signal induced the highest levels of antibodies and impacted Ig isotype distribution, consistent with the presence of a CD1-restricted pathway of Ig formation to GPI-anchored membrane proteins. Despite the induction of specific antibodies, none of these DNA vaccines induced sufficient levels of antibodies to protect mice against a lethal challenge with P. yoelii.
Leishmania are protozoan parasites responsible for a spectrum of diseases collectively known as l... more Leishmania are protozoan parasites responsible for a spectrum of diseases collectively known as leishmaniasis. The disease is a significant health problem in many regions of the world and emerges as a serious co-infection in HIV-positive individuals. Current treatment of the disease is based on a limited number of chemotherapeutic agents which are rapidly becoming ineffective, and are characterized by high toxicity and cost. This review focuses on recent advances in antileishmanial drug development and improvements to current treatment options. Novel approaches currently used to identify leishmanicidal compounds as diverse as antimicrobial peptides and natural plant extracts are described in this review.
Leishmania are protozoan parasites spread by a sandfly insect vector and causing a spectrum of di... more Leishmania are protozoan parasites spread by a sandfly insect vector and causing a spectrum of diseases collectively known as leishmaniasis. The disease is a significant health problem in many parts of the world, resulting in an estimated 1•3 million new cases and 30 000 deaths annually. Current treatment is based on chemotherapy, which is difficult to administer, expensive and becoming ineffective in several endemic regions. To date there is no vaccine against leishmaniasis, although extensive evidence from studies in animal models indicates that solid protection can be achieved upon immunization. This review focuses on immune responses to Leishmania in both cutaneous and visceral forms of the disease, pointing to the complexity of the immune response and to a range of evasive mechanisms utilized by the parasite to bypass those responses. The amalgam of innate and acquired immunity combined with the paucity of data on the human immune response is one of the major problems currently hampering vaccine development and implementation.
All reactions were conducted using 5.0 mmol of antimony(V) dibromide precursor and 10.0 mmol of p... more All reactions were conducted using 5.0 mmol of antimony(V) dibromide precursor and 10.0 mmol of potassium or sodium salt of carboxylic acid. Aryl substituted antimony(V) dibromide was ground together with the chosen carboxylic acid salt and dried in vacuo prior to use. The mixture of reagents were placed in a Schlenk flask with dried toluene (ca 100 mL) and stirred for 12 hours. The salt(s) formed were filtered off and the resulting clear solution was removed under reduced pressure to yield a solid residue. Synthesis of bis-(2-thiophenecarboxylato)triphenylantimony(V), [SbPh 3 (C 4 H 3 SCO 2) 2 ], 12 Reaction of triphenylantimony(V) dibromide (2.56 g, 5 mmol) with the potassium salt of 2-thiophenecarboxylic acid (1.66 g, 10 mmol) was performed and purified according to GP, producing a colourless solid. This was identified as 12.
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Papers by Lukasz Kedzierski