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"Tonge, Ashley"
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Tether mutations that restore function and suppress pleiotropic phenotypes of the C. elegans isp-1(qm150) Rieske iron–sulfur protein
2015
SignificanceMitochondrial function is critical for health and longevity. Mutation of the highly conserved Rieske iron–sulfur subunit (ISP-1) of complex III in the respiratory chain results in pleiotropic phenotypes in Caenorhabditis elegans, including delayed development and increased lifespan. We identified intragenic mutations within a conserved 6-aa tether region of ISP-1. These suppressors are capable of suppressing all of the phenotypes associated with the isp-1(qm150) mutation. We further demonstrated that this mutation/suppressor relationship is conserved in the Rieske iron–sulfur protein (Rip1) of yeast complex III. These findings provide insights into conserved features of the structure and function of this protein, and allow us to propose a unique “spring-loaded” mechanism to account for these effects, supported by empirical physicochemical data.
Mitochondria play an important role in numerous diseases as well as normative aging. Severe reduction in mitochondrial function contributes to childhood disorders such as Leigh Syndrome, whereas mild disruption can extend the lifespan of model organisms. The Caenorhabditis elegans isp-1 gene encodes the Rieske iron–sulfur protein subunit of cytochrome c oxidoreductase (complex III of the electron transport chain). The partial loss of function allele, isp-1(qm150), leads to several pleiotropic phenotypes. To better understand the molecular mechanisms of ISP-1 function, we sought to identify genetic suppressors of the delayed development of isp-1(qm150) animals. Here we report a series of intragenic suppressors, all located within a highly conserved six amino acid tether region of ISP-1. These intragenic mutations suppress all of the evaluated isp-1(qm150) phenotypes, including developmental rate, pharyngeal pumping rate, brood size, body movement, activation of the mitochondrial unfolded protein response reporter, CO2 production, mitochondrial oxidative phosphorylation, and lifespan extension. Furthermore, analogous mutations show a similar effect when engineered into the budding yeast Rieske iron–sulfur protein Rip1, revealing remarkable conservation of the structure–function relationship of these residues across highly divergent species. The focus on a single subunit as causal both in generation and in suppression of diverse pleiotropic phenotypes points to a common underlying molecular mechanism, for which we propose a “spring-loaded” model. These observations provide insights into how gating and control processes influence the function of ISP-1 in mediating pleiotropic phenotypes including developmental rate, movement, sensitivity to stress, and longevity.
Journal Article
Tether mutations that restore function and suppress pleiotropic phenotypes of theC. elegans isp-1(qm150)Rieske iron–sulfur protein
2015
Mitochondria play an important role in numerous diseases as well as normative aging. Severe reduction in mitochondrial function contributes to childhood disorders such as Leigh Syndrome, whereas mild disruption can extend the lifespan of model organisms. TheCaenorhabditis elegans isp-1gene encodes the Rieske iron–sulfur protein subunit ofcytochrome coxidoreductase (complex III of the electron transport chain). The partial loss of function allele,isp-1(qm150),leads to several pleiotropic phenotypes. To better understand the molecular mechanisms of ISP-1 function, we sought to identify genetic suppressors of the delayed development ofisp-1(qm150)animals. Here we report a series of intragenic suppressors, all located within a highly conserved six amino acid tether region of ISP-1. These intragenic mutations suppress all of the evaluatedisp-1(qm150)phenotypes, including developmental rate, pharyngeal pumping rate, brood size, body movement, activation of the mitochondrial unfolded protein response reporter, CO₂ production, mitochondrial oxidative phosphorylation, and lifespan extension. Furthermore, analogous mutations show a similar effect when engineered into the budding yeast Rieske iron–sulfur protein Rip1, revealing remarkable conservation of the structure–function relationship of these residues across highly divergent species. The focus on a single subunit as causal both in generation and in suppression of diverse pleiotropic phenotypes points to a common underlying molecular mechanism, for which we propose a “spring-loaded” model. These observations provide insights into how gating and control processes influence the function of ISP-1 in mediating pleiotropic phenotypes including developmental rate, movement, sensitivity to stress, and longevity.
Journal Article
Monkeypox virus-infected individuals mount comparable humoral immune responses as Smallpox-vaccinated individuals
by
Rowe, Cathy
,
Mehta, Ravi
,
Otter, Ashley D.
in
631/250/255/2514
,
631/326/2521
,
631/326/590/1867
2023
In early 2022, a cluster of monkeypox virus (MPXV) infection (mpox) cases were identified within the UK with no prior travel history to MPXV-endemic regions. Subsequently, case numbers exceeding 80,000 were reported worldwide, primarily affecting gay, bisexual, and other men who have sex with men (GBMSM). Public health agencies worldwide have offered the IMVANEX Smallpox vaccination to these individuals at high-risk to provide protection and limit the spread of MPXV. We have developed a comprehensive array of ELISAs to study poxvirus-induced antibodies, utilising 24 MPXV and 3 Vaccinia virus (VACV) recombinant antigens. Panels of serum samples from individuals with differing Smallpox-vaccine doses and those with prior MPXV infection were tested on these assays, where we observed that one dose of Smallpox vaccination induces a low number of antibodies to a limited number of MPXV antigens but increasing with further vaccination doses. MPXV infection induced similar antibody responses to diverse poxvirus antigens observed in Smallpox-vaccinated individuals. We identify MPXV A27 as a serological marker of MPXV-infection, whilst MPXV M1 (VACV L1) is likely IMVANEX-specific. Here, we demonstrate analogous humoral antigen recognition between both MPXV-infected or Smallpox-vaccinated individuals, with binding to diverse yet core set of poxvirus antigens, providing opportunities for future vaccine (e.g., mRNA) and therapeutic (e.g., mAbs) design.
In this work, Otter et al. compared the humoral immune responses induced by MPXV infection and Smallpox vaccination. Although comparable responses were observed, infection- or vaccination specific serological markers were identified enabling discrimination between vaccinated and infected individuals.
Journal Article
Ready-to-use iPSC-derived microglia progenitors for the treatment of CNS disease in mouse models of neuropathic mucopolysaccharidoses
2024
Mucopolysaccharidoses are inherited metabolic disorders caused by the deficiency in lysosomal enzymes required to break down glycosaminoglycans. Accumulation of glycosaminoglycans leads to progressive, systemic degenerative disease. The central nervous system is particularly affected, resulting in developmental delays, neurological regression, and early mortality. Current treatments fail to adequately address neurological defects. Here we explore the potential of human induced pluripotent stem cell (hiPSC)-derived microglia progenitors as a one-time, allogeneic off-the-shelf cell therapy for several mucopolysaccharidoses (MPS). We show that hiPSC-derived microglia progenitors, possessing normal levels of lysosomal enzymes, can deliver functional enzymes into four subtypes of MPS knockout cell lines through mannose-6-phosphate receptor-mediated endocytosis in vitro. Additionally, our findings indicate that a single administration of hiPSC-derived microglia progenitors can reduce toxic glycosaminoglycan accumulation and prevent behavioral deficits in two different animal models of MPS. Durable efficacy is observed for eight months after transplantation. These results suggest a potential avenue for treating MPS with hiPSC-derived microglia progenitors.
Mucopolysaccharidoses (MPS) are inherited metabolic disorders caused by enzyme deficiencies leading to glycosaminoglycan accumulation and systemic degenerative disease. Here, the authors show that iPSC-derived microglia progenitors can reduce glycosaminoglycan accumulation and prevent behavioral deficits in MPS mouse models.
Journal Article
Evaluation of a multiplexed immunoassay for assessing long-term humoral immunity Orthopoxviruses
by
Hicks, Bethany
,
Gordon, Claire
,
Jones, Rachael
in
Adolescent
,
Allergy and Immunology
,
Antibodies
2024
The 2022 Monkeypox virus (MPXV) global outbreak boosted development of multiple serological assays to aid understanding of Mpox immunology.
The study aimed to assess a multiplexed solid-phase electrochemiluminescence immunoassay (Meso Scale Discovery (MSD)) for simultaneous detection of antibodies against MPXV, including A35, E8 and M1 antigens, along with corresponding Vaccina Virus (VACV) homologues and demonstrate its accuracy in assessing antibody titres post-vaccination and infection.
Assay performance was assessed for simultaneous detection of antibodies against MPXV and corresponding VACV antigens. Sensitivity and specificity were evaluated with paediatric negatives (n = 215), pre- and post-IMVANEX vaccinated (n = 80), and MPXV (Clade IIb, n = 39) infected serum samples.
The assay demonstrated high specificity (75.68 % (CI: 69.01–81.29) - 95.98 % (CI:92.54–97.87)) and sensitivity (62.11 % (CI:52.06–71.21) - 98.59 % (CI:92.44 %–99.93 %)) depending on the Orthopoxvirus antigen. Preferential binding was observed between MPXV-infected individuals and MPXV antigens, while vaccinated individuals exhibited increased binding to VACV antigens. These results highlight differential binding patterns between antigen homologues in related viruses.
Overall, this assay demonstrates high sensitivities in detecting antibodies for multiple relevant MPXV and VACV antigens post-infection and post-vaccination, indicating its utility in understanding immune responses to Orthopoxviruses in current and future outbreaks and evaluating the immunogenicity of new-generation Mpox-specific vaccinations.
•Simultaneous measurement of IgG to multiple MPXV and VACV homologous proteins•Sensitive and specific assay for detecting Orthopoxvirus antibodies•Detects Orthopoxvirus IgG antibodies in vaccinated sera 220 days after two doses•Mpox-infected individuals show preferential binding to MPXV over VACV antigens•Higher anti-MPXV A29 and anti-VACV A27 IgG titres post infection versus vaccination
Journal Article