Biology subjects

Jeffrey, K.

Publications and source records attributed to Jeffrey, K..

4 recordsLinked to original sources

bioRxiv2024

An NADH-controlled gatekeeper of ATP synthase

ATP fuels crucial cellular processes and is obtained mostly by oxidative phosphorylation (OXPHOS) at the inner mitochondrial membrane. While significant progress has been made in mechanistic understanding of ATP production, critical aspects surrounding its substrate supply logistics are poorly understood. We identify an interaction between mitochondrial apoptosis-inducing factor 1 (AIFM1) and adenylate kinase 2 (AK2) as gatekeeper of ATP synthase. This interaction is NADH-dependent and influenced by glycolysis, linking it to the cells metabolic state. Genetic interference with AIFM1/AK2 association impedes the ability of Caenorhabditis elegans animals to handle altered metabolic rates and nutrient availability. Together, the results imply AIFM1 as a cellular NADH sensor, placing AK2 next to the OXPHOS complexes for local ADP regeneration as the substrate for ATP synthesis. This metabolic signal relay balances ATP synthase substrate supply against ATP conservation, enabling cells to adapt to fluctuating energy availability, with possible implications for AIFM1-related mitochondrial diseases. HighlightsO_LIDiscovery of AIFM1/AK2 interaction as a gatekeeper of mitochondrial ATP synthase C_LIO_LIAIFM1/AK2 interaction is NADH-dependent and linked to the cells metabolic state C_LIO_LIDisrupting AIFM1/AK2 impairs metabolic adaptation in Caenorhabditis elegans C_LIO_LIAIFM1 as NADH sensor, influencing ATP synthesis with mitochondrial disease implications C_LI

biochemistry↗

bioRxiv2024

SID-2 localises to extracellular vesicles in parasitic nematodes and does not function in environmental RNAi

In the free-living nematode Caenorhabditis elegans the transmembrane protein SID-2 imports double-stranded RNA into intestinal cells to trigger systemic RNA interference (RNAi), allowing organisms to sense and respond to environmental cues such as the presence of pathogens. This process, known as environmental RNAi, has not been observed in the most closely related parasites that are also within clade V. Previous sequence-based searches failed to identify sid-2 orthologs in available clade V parasite genomes. In this study we identified sid-2 orthologues in these parasites using genome synteny and protein structure-based comparison, following identification of a SID-2 orthologue in extracellular vesicles from the murine intestinal parasitic nematode Heligmosomoides bakeri. Expression of GFP-tagged H. bakeri SID-2 in C. elegans showed comparable localisation to the intestinal apical membrane as seen for GFP-tagged C. elegans SID-2 and further showed mobility in intestinal cells in vesicle-like structures. We tested the capacity of H. bakeri SID-2 to functionally complement environmental RNAi in a C. elegans SID-2 null mutant and show that H. bakeri SID-2 does not rescue the phenotype in this context. Therefore, our work identifies SID-2 as a highly abundant nematode EV protein whose ancestral function may be unrelated to environmental RNA and rather highlights an association with extracellular vesicle-mediated communication in free-living and parasitic nematodes.

evolutionary biology↗

bioRxiv2022

Immune chromatin reader SP140 regulates microbiota and risk for inflammatory bowel disease

Inflammatory bowel disease (IBD) is driven by host genetics and environmental factors, including commensal microorganisms. Epigenetics facilitate integration of environmental cues for transcriptional output. However, evidence of epigenetic dysregulation directly causing host-commensal dysbiosis and IBD is lacking. Speckled Protein 140 (SP140) is an immune-restricted chromatin reader with homology to Autoimmune Regulator (AIRE). SP140 mutations associate with three immune diseases: Crohns disease (CD), multiple sclerosis (MS) and chronic lymphocytic leukemia (CLL), but disease-causing mechanisms remain undefined. Here we identify a critical immune-intrinsic role for SP140 in preventing expansion of inflammatory Proteobacteria, including Helicobacter in mice and Enterobacteriaceae in humans. Mice harboring altered microbiota due to hematopoietic Sp140 deficiency exhibited severe colitis which was transmissible upon co-housing and ameliorated with antibiotics. SP140 was critical for calibration of macrophage microbicidal responses required for normal host-commensal crosstalk and elimination of invasive pathogens. Mutations within this epigenetic reader may constitute a predisposing event in human diseases provoked by the microbiome, such as IBD and MS.

immunology↗

bioRxiv2018

Whole genome sequencing for predicting Mycobacterium abscessus drug susceptibility

Mycobacterium abscessus is emerging as an important pathogen in chronic lung diseases with concern regarding patient to patient transmission. The recent introduction of routine whole genome sequencing (WGS) as a replacement for existing reference techniques in England provides an opportunity to characterise the genetic determinants of resistance. We conducted a systematic review to catalogue all known resistance determining mutations. This knowledge was used to construct a predictive algorithm based on mutations in the erm(41) and rrl genes which was tested on a collection of 203 sequentially acquired clinical isolates for which there was paired genotype/phenotype data. A search for novel resistance determining mutations was conducted using an heuristic algorithm.\n\nThe sensitivity of existing knowledge for predicting resistance in clarithromycin was 95% (95% CI 89 - 98%) and the specificity was 66% (95% CI 54 - 76%). Subspecies alone was a poor predictor of resistance to clarithromycin. Eight potential new resistance conferring SNPs were identified. WGS demonstrates probable resistance determining SNPs in regions the NTM-DR line probe cannot detect. These mutations are potentially clinically important as they all occurred in samples predicted to be inducibly resistant, and for which a macrolide would therefore currently be indicated. We were unable to explain all resistance, raising the possibility of the involvement of other as yet unidentified genes.

microbiology↗