Biology subjects

Lloyd, T. E.

Publications and source records attributed to Lloyd, T. E..

3 recordsLinked to original sources

bioRxiv2021

Prevalence, persistence, and genetics of antibody responses to protein toxins and virulence factors

Microbial exposures are crucial environmental factors that impact healthspan by sculpting the immune system and microbiota. Antibody profiling via programmable Phage ImmunoPrecipitation Sequencing (PhIP-Seq) provides a high-throughput, costeffective approach for multiplexed detection of exposure and response to thousands of microbial protein products. Here we designed and constructed a library of 95,601 56 amino acid peptide tiles spanning a subset of environmental proteins more likely to be associated with immune responses: those with "toxin" or "virulence factor" keyword annotations. PhIP-Seq was used to profile the circulating antibodies of ~1,000 individuals against this "ToxScan" library of 14,430 toxins and virulence factors from 1,312 genera of organisms. In addition to a detailed analysis of six commonly encountered human commensals and pathogens, we study the age-dependent stability of the ToxScan profile and use a genome-wide association study (GWAS) to find that the MHC-II locus modulates the selection of bacterial epitopes. We detect previously described anti-flagellin antibody responses in a Crohns disease cohort and identify a novel association between anti-flagellin antibodies and juvenile dermatomyositis (JDM). PhIP-Seq with the ToxScan library provides a new window into exposure and immune responses to environmental protein toxins and virulence factors, which can be used to study human health and disease at cohort scale.

immunology↗

bioRxiv2021

Loss of TDP-43 function and rimmed vacuoles persist after T cell depletion in a xenograft model of sporadic inclusion body myositis

Sporadic inclusion body myositis (IBM) is the most common acquired muscle disease in adults over age 50, yet it remains unclear whether the disease is primarily driven by T cell-mediated autoimmunity. IBM muscle biopsies exhibit nuclear clearance and cytoplasmic aggregation of TDP-43 in muscle cells, a pathologic finding observed initially in neurodegenerative disease, and nuclear loss of TDP-43 in neurons causes aberrant RNA splicing. Here, we show that loss of TDP-43 splicing repression, as determined by inclusion of cryptic exons, occurs in skeletal muscle of IBM patients. Out of 119 muscle biopsies tested, RT-PCR-mediated detection of cryptic exon expression is 84% sensitive and 99% specific for diagnosing IBM, indicating utility as a functional and diagnostic biomarker. To determine the role of T cells in pathogenesis, we generated a novel xenograft model by transplanting human IBM muscle into the hindlimb of immunodeficient mice. Xenografts from IBM patients display robust regeneration of human myofibers and recapitulate both inflammatory and degenerative features of the disease. Myofibers in IBM xenografts are invaded by human, oligoclonal CD8+ T cells and exhibit MHC-I upregulation, rimmed vacuoles, mitochondrial pathology, p62-positive inclusions, and nuclear clearance and cytoplasmic aggregation of TDP-43, resulting in expression of cryptic exons. Depletion of human T cells within IBM xenografts by treating mice intraperitoneally with anti-CD3 (OKT3) suppresses MHC-I upregulation, but rimmed vacuoles and loss of TDP-43 function persist. These data suggest that myofiber degeneration occurs independent of T cells, and muscle cell-intrinsic mechanisms, such as loss of TDP-43 splicing repression, drive IBM pathogenesis. One Sentence SummaryDepletion of T cells in a xenograft model of sporadic inclusion body myositis suppresses inflammation but not TDP-43 pathology or muscle degeneration.

pathology↗

bioRxiv2020

An integrated multi-omic analysis of iPSC-derived motor neurons from C9ORF72 ALS patients

Neurodegenerative diseases present a challenge for systems biology, due to the lack of reliable animal models and the difficulties in obtaining samples from patients at early stages of disease, when interventions might be most effective. Studying induced pluripotent stem cell (iPSC)-derived neurons could overcome these challenges and dramatically accelerate and broaden therapeutic strategies. Here we undertook a network-based multi-omic characterization of iPSC-derived motor neurons from ALS patients carrying genetically dominant hexanucleotide expansions in C9orf72 to gain a deeper understanding of the relationship between DNA, RNA, epigenetics and protein in the same pool of tissue. ALS motor neurons showed the expected C9orf72-related alterations to specific nucleoporins and production of dipeptide repeats. RNA-seq, ATAC-seq and data-independent acquisition mass-spectrometry (DIA-MS) proteomics were then performed on the same motor neuron cultures. Using integrative computational methods that combined all of the omics, we discovered a number of novel dysregulated pathways including biological adhesion and extracellular matrix organization and disruption in other expected pathways such as RNA splicing and nuclear transport. We tested the relevance of these pathways in vivo in a C9orf72 Drosophila model, analyzing the data to determine which pathways were causing disease phenotypes and which were compensatory. We also confirmed that some pathways are altered in late-stage neurodegeneration by analyzing human postmortem C9 cervical spine data. To validate that these key pathways were integral to the C9 signature, we prepared a separate set of C9orf72 and control motor neuron cultures using a different differentiation protocol and applied the same methods. As expected, there were major overall differences between the differentiation protocols, especially at the level of in individual omics data. However, a number of the core dysregulated pathways remained significant using the integrated multiomic analysis. This new method of analyzing patient specific neural cultures allows the generation of disease-related hypotheses with a small number of patient lines which can be tested in larger cohorts of patients.

neuroscience↗